Picking up where we left off...

It looks like they want me to put something like 400 feet of plastic pipe in the lake. This is for a 5-6 ton unit. I want to try something different.

I can build a radiator out of hard copper pipe. I picture a 2" manifold branching into multiple 3/4 or 1/2 inch rods. I can find the thermal transfer characteristics of copper on the net, and then build it twice as big. Can't loose too much heat, right? I can silver solder it up tight so it won't leak.

Now the good part...I bet the fish would love it!

Wadda ya think?

Hot in the Summer, Cold in the Winter - sounds like the rental house we lived in when we were first married.

Jersey- You would need more than 400ft, mine is at 4 ton and at 900ft. I posted these before, it should give you a idea of the area covered
- Brian

The company that installed my system used poly pipe similar to Mr. Willy's. They formed a "mat" about 50'x50' out of plastic snow fence by zip tying it together. Coils of the poly pipe were spread neatly across the mat, layed flat, and zip tied to the mat along with concrete blocks for weight. The whole contraption was drug into the pond. The installers said they prefered to do it in when ponds were frozen so they could built it in place and just let it sink. The installers also said they were putting in a 100 ton system to heat the new horse arena and stables at the Fairgrounds. This system would use 20 of these "mats" sunk in the nearby quarry. Just thought it was interesting.

900 FEET !!!

I'm starting to like this radiator idea more and more!

"I can build a radiator out of hard copper pipe. I picture a 2" manifold branching into multiple 3/4 or 1/2 inch rods."

Jersey, I hate to break up a good brainstorm but
from this description I am imagining something that resembles a TV antenna with either A:the copper pipes ending and capped off or B: routing back to the manifold. If this is what you are invisioning I think there may be a problem with your design. If your idea is method A: the fluid will pass from the inlet straight through the manifold and directly to the outlet with little heat loss/gain (depending if you are in Heat/cool mode). If method B: the fluid running through the rods will cross/mix with the fluid traveling through the manifold resulting in fluid exiting not at it's full exchange potential lessening the systems efficiency.

Copper makes sense because of it's conduction properties and longevity. It seems that a long (how long?) continuous coil would be simpler, more effective, and not require a manifold. Aluminum has even better properties than copper but the costs of both are very high.

So far everyone is telling me not to aerate unless my pond is over 20' deep or very large since my system was designed without the consideration of aeration. I expect a communication from my manufactures engineer(s) on Monday hopefully with some definite answers.

Another thought to ponder for those putting in new systems would be to go with an open loop system. A well would have to be drilled or some other water source, and the water would be pumped through the system and discharge into the pond. Keeping it full. Could possibly support trout if properly designed. The discharge water could be sprayed adding a little aeration too.

Actually, I was envisioning two 2" copper pipes spaced about 10' apart and connected together with maybe twenty 1/2" copper tubes. One 2" pipe would be the intake manifold, the other the exhaust manifold. The water would have to flow through the 1/2" tubes.

The geothermal heat pump is for my house, not the pond. The pond serves as a source of heat in the winter, and as a place to dump heat in the summer. The one I am looking at claims to be 350% efficient.

Remember I am in Georgia and will have a 7 acre pond with a spring fed creek in it. Stagnation won't be an issue.

Jersey, you have inspired me to research and compare prices (please tell my boss how you did it).

Prices per Graingers

400 feet 1.25" plastic pipe - $300

"radiator" total $900+
Qty 20 10'joints 1" copper - $300
Qty 1 10' joint 2" copper - $75
Qty 40 2"x2"x3/4" copper tees - $520
(sorry, couldn't find them 2"x2"x1/2")
Qty 40 3/4"x1/2" reducers - $40

Now we know why commercial installers use great lengths of plastic pipe.

Mr Freeze...
....so darn glad that you decided to jump in on the forum. I am in the midst of a 5a pond in the midwest that will have a retirement home built next to it in about 4 years or so. I am twistin' my brain and relying heavily on this forum to prepare and execute all the smart stuff before the hole fills up. We cut in a driveway and cleared an opening in the forest this year for the project and plan to bottomscape and build the dam next summer/fall.
I am very hands-on and have always been intrigued by geothermal heat pumps. I have a buncha questions, but my focus is mostly on the preparation related to the near term. I love the idea of the snow fence and cinderblock idea. Considering my project and knowing that the building site will be about 100 ft p/m from the waterline, what would you do to prepare? I envision laying a mat of pipes in the bottom and running the supply and return ends back up thru the soil below the frost line to the approx area of the home. Then, maybe cap the ends and bury them with a marker? Will the field be a floating problem? How do the pros run the supply/return? Are there multiple supply/returns for different zones in case one fails?

Theo,
Now that's the part I hadn't figured out yet. Hmmm...I may have to do some more research.

If you figured out all the heat transfer coefficients (an ME could do it; I probably could have done it 25 years ago right after taking a required ME heat transfer class) you could know what size copper radiator would be equivalent to what length of plastic pipe (probably have to figure relative flow restrictions due to friction as well), but there's a sizable material cost difference and I think the labor would be the real killer (unless you really enjoy soldering). There might be some circumstances (very small backyard pond) where it might be prohibitive to fit in a great big length of pipe where the radiator approach might make more sense.

Different thought, same thread: I was thinking about sediment and muck covering the pipe (or radiator) on the bottom of a pond and I don't think it would hurt the heat transfer any/much. You'd still be thermally tied into the Earth's mass, by wet mud/muck.

following Theo's comment regarding bottom muck....
When the line is buried in normal soil at the correct depth, the temp is nearly constant throughout the year at approx 57 degrees, p/m. When it is in a pond at 8' min depth, what are the temp swings? Is it possible that it is advantageous to bury the lines below the pond bottom surface to achieve the temp consistency that cools best in the summer and heats best in the winter? I guess the bottom line is: what are the ambient temps at 8 - 10 feet deep in a pond in the midwest during hottest summer and coldest winter temps?

Brettski, I am by far an expert on Geo systems and can only speak from my limited experience on my own. I recommend getting as much info as you can from an insaller and or manufacturer. For planning purposes I can give you a few tidbits I picked up that may benifit you. Putting the loop in before the pond fills is a good idea because a trench had to be dug to mine after it was filled resulting in a spot that has been difficult to smooth out and a steep hole where they didn't fill it back in enough just below the water surface. My installer said that the inlet/outlet pipes need to be a certain distance apart and not cross water lines if possible because the ground will freeze deeper where the geo is sucking heat out of the ground. Will the mat float? I'm not sure. I would contact installers and leave it up to the pros. I'm a big doityourselfer, but I believe repairs/replacement later would be expensive if not done correctly.

As far as the muck goes, the manufacturer did say that it wouldn't be a problem for basically the same reason as Brettski theorized.

Ryan,
your note about the trench is pretty much the first thing that popped into my little brain when I started considering possible advantages of doing this before water retention. So, there is a trench that is below frost line (perhaps well below) that the lines run in from the pond to the home foundation...? Are there basically 2 lines (supply & return), or are there multiple loops. I read somewhere in the near past that it is normal to set up multiple loops in case one fails. In fact, I believe it related to a soil burial project and the extra loops were not even employed....cheap insurance in case one fails. Regarding the loop grid, can you paint a picture of the layout and spacing of the 900 linear feet? I have to imagine that alot of the piping was very close to a neighboring line. Was any of it left in a "factory coil", or was it all stretched out? Oh yeah, just a little more....how big is the temp controlled area and how many ton unit? What brand?
thx

Brettski, go back to my original post that this spun off of 1st pond 1st post, my story some of your questions can be answered there. I will find out exactly how many feet of poly pipe was used and try to get a picture of a mat. 5ton system, 3500sq ft. plus 2000 sq ft basement.

done, duh, thanks

Here's the bad news about geothermal. According to information I just received from Climate Master Engineers via a rep. from my HVAC installers "Absolutely under no circumstances aerate your pond. You want an ice layer to form in winter and the pond to be stratisfied in summer in order for the system to operate properly." This is just in the case of my 1/2acre pond and my system. Others may have different scenarios. If a person is planning to aerate and use a closed pond loop Geothermal system, they should consult their manufacturer or qualified installer prior to installation to see if it is possible or pursue other Geo or traditional alternatives.

I've posted on geo-thermal before. Why is everyone sinking piping in their ponds? If you have a strong ground water source, just pump from your well through the geo units and dump to the pond. Ground water has a consistent temperture year round, and you save a bundle on all the piping and pumps needed for a close loop system. I hope no one fishes these ponds? One sharp hook in a pipe and all your anti-freeze goes into the pond. I'm sure the piping is tough to penitrate, but you have to careful. I'm been using a "pump and dump" set up for 5 years now in cold michigan, and my home is cool in the summer and toasty in the winter. I did have to spend more on an upgraded well, but the additional cost isn't nearly what these close loop installers charge, and open loop systems are way more efficient than close loop. Check out the manufacturers efficiency specs of the machinery with each style of loop. Open loop is much more efficient, an lower cost to install. The only catch is you need a realible source of ground water to pump. Just my thoughts.

Country....
soakin' up the input....many thanks. Is the well source the same that you use for drinking water? If yes, I assume that you just tap off of the pressure tank and go directly to the heat pump? What about mineral build up in the heat pump unit due to un-softened water?

Good thread. After reading these posts and researching further I think the open loop route is the way we'll go. I think the flow rate of our well is sufficient but I'll have to check it out.I'd certainly like to hear more about the mineral deposits and if any type of filtration is needed for the iron.
Chip

In my case my well for the house would not have produced enough water for both the Geo and normal water useage. The cost for an additional well exceeded the cost of the loop. Only by about $300+additional electric lines. The rep also said it was cheaper to circulate water as opposed to pumping water 1 way. Keeping the pond fuller and the ability to add aeration are definitely attractive benefits of an open loop system. I'd be interested in finding out if the efficiency increase outweighs the cost of pumping. If my loop were to fail I will seriously reconsider the open loop system.

Sounds like Chip has the same rusty water up in Lima as we do. I'm interested in answers about mineral build up but I never heard of anyone in my area's pipes clogging due to mineral build up before it gets to the softener. I let my softener in a house I lived in up the road run out of salt once and it turned my shower bright orange in just a couple of days. Took some nasty chemicals to remove the stains.

Seems like we're raising more questions than answers. I'm surpised their isn't an HVAC expert that is also a PB member.

I have been considering and reading about systems for a while now, and it seems like the perfect type of system if you have a place to loose the heat like a pond or abundant well. I have learned a lot about them, but have not yet seen a spec on the output water temp, or the heat rise of the system.

Now, I know that plastic isn't a very good conductor of heat, so it makes sense that it would take a lot of submerged plastic pipe to loose 3 or 4 tons of heat. I'm just surprised to hear 900 feet!

That's still why I like my copper radiator idea. I guess I need to do some reasearch into the heat transfer characteristics of PVC and copper. Pretty exciting, huh?

Does the geo system include a heat exchanger for your domestic water?
That would be free hot water in the summer.

Ric, yes my system does "preheat" the water entering into my water heater. It does so in both winter and summer. I'm not sure how much of a difference it makes but a recent flyer sent from our power company said about 20% of an all electric home's power consumption is due to heating water. All the Geo systems I looked at had this feature built in ready for plumbing to the water heater.

If you have a radiant floor system, they recommend running all of your water through the slab before it gets heated. This cools the slab, which is "free" air conditioning.

Sorry I haven't gotten back sooner. I've been traveling for work. There is no issue with mineral deposits in the geo unit using as open loop. The entire system is pressurized just like your well pressure tanks. Mineral doesn't deposit in your well pressure tanks, the geo unit is no different. Minerals can only deposit when there is no pressure and the presents of air or oxygen. The valve that allows the water to flow through the geo unit is on the water output side of the plumbing. That way the heat exchanger and coils are always under pressure originating at pressurized well tanks. I use my homes normal well tanks for the house water as the geo water source. I tap is off the tanks before the water softener. As far as the well goes, I had to go deeper to get the quantity of water I needed for the geo units, and I has to add a couple of extra pressure tanks to make sure the well pump doesn't cycle too often. As an extra bonus, check out your local power company. Most of them have preferred electrical rates for geo customers, usually less than half what you normally pay. You will have to have a separate meter and electrical panel, but that cost is minor to the huge savings you get by using electricity to power the geo units. Because the well is now needed to run the geo units, the well pump can be tied into the separate geo electrical panel too, so whenever you use the well pump, even if it’s for the normal house water, you pay the reduced electrical rates. As an example, in Michigan the normal electrical rates are around $0.11 per Kilowatt hour, my geo rates vary by time of day anywhere from $0.07 / KWH to as low as $0.029 / KWH. As you can see, the savings is huge.

I also use the geo units to preheat my hot water for the house. I preheat up to 90F, and yes, your electrical usage is all at that reduced rate!

Great post, Country....it really opens up alot of considerations. Can you describe the "dumping" procedure of the waste water? How does the exit maintain the pressure...a check valve or sorts? and...how do you channel the water back to the pond; a below frost-line pipe?
Also, really curious about the water supply system setup. Specifics on the pressure tank sizes? The HP of the well pump?
Thx
Brettski

Since Country Boy brought up pressure tanks, this is off the geo subject but loosly related. The system we used has a tiny pressure tank. Only about 1 1/2 gal. It has a control unit that by the push of a button you can change your water pressure. You can crank it up until the pressure valve blows, believe me I know, and it comes with lock to prevent you from cranking it up too high, if you set it, don't ask. We can turn on every faucet in the house with no noticeable drop and the pressure is excellent. We have been plagued with poor pressure in other houses and this was a priority for us. Just something else to consider. Like there isn't already enough decisions to make.

Thanks for the posts guys, this has really got my squirrel cage a turnin'. I haven't had a chance to check on the flow requirements for our particular situation but one GT unit I was browsing claimed they ONLY used 2 cfm of water for operation or about 15 gallons per minute. I expect ours would be quite a bit more than that because the house is bigger than most of the case studies I've looked at. We have a separate pond water pump and pressure tank system and pickup already installed. I may have to draw off the pond for household water and just use the well for drinking water and the heat pump.Is anyone else set up for pond water household supply? Does the hot water side of the unit care where the water comes from or is limited to just the well source?
Chip

Here is a link to more information than I know what to do with:

Water Furnace Specs

I have 5 well tanks, one for each geo unit. Yes, this is a big house! Once the water exits the pressure valve on the output side of the geo unit, the pressure drops to zero, and it is a gravity feed out the wall of the house and flows by gravity in a 4 in" PVC pipe to the pond. It dumps above the surface of the water (important) at the edge of the pond. It doesn't have to be below the frost line because the water is always moving. It won't freeze in the pipe. I see on some of the posts that someone is using 15 gallons/ min. WOW! I think they must be quoting close loop anti-freeze flows. The nice thing about open loop is, because the water is both warmer in the winter and cooler in the summer than closed loop, you don't need nearly as much flow to get the desired effects. My basement unit is a 5.5 ton unit, and it has a flow regulator pegged at no more than 7 gallons/ min. A closed loop would probably be in that 15 gallon /min range to get the heat or cooling effects needed.

Think about some of the posts hear. Some are talking about the coils freezing into huge blocks of ice at the bottom of the pond in the winter. Well ice is 32F and your geo unit is trying to extract heat from it! Not that efficient. In the summer, assuming you aerate the pond, once it de-stratifies, will be in that 70F range (Michigan weather) and that’s your source of cooling! Sure, the geo unit uses a compressor cycle, but you need a lot of flow too achieve good cooling. Frankly for heating, I'd rather bury the coils 4-5 ft in the ground. At least there, in cooling mode, you can use the cool earth as your heat sink.

Of course, I'm a big open loop advocate, in the winter; my input water is 50F, in the summer, its 50F. For me it's the only way to go.

OK Country, your pitch is strong and definitely has my attention. My proposed home project is gonna be quite the opposite of your's. I anticipate a much smaller structure; a tight, efficient chalet looking over the pond. Size? Probably a 28' x 44'full basement footprint and 1.5 stories. With your exposure and background on the "pump and dump", can you dare a guess on possible equipment needs?...3 or 4 tons? I gotta guess that one sizeable dedicated pressure tank will git it...? I think my biggest fear of open loop is the water supply end. I keep thinking of a 1 HP 220v pump cycling every 5 minutes and the related energy costs and wear/tear on the pump. I am in a county that offers a co-op division of Touchstone Energy. I am going to reach out to ask about installation rebate programs and usage discounts, but I fear a midwest farmer community co-op will have little to offer.
Also, I wholely agree (or at least question, as noted in a previous post) that the consistent temp of a grade burial closed-loop is likely more efficient than temp swings of pond water; well water would naturally follow the same.
I like your thinking and appreciate your participation...thanks.

Your radiator type heat exchanger in your pond sounds like the same style as the slim jim which is metal and takes up very little space. I am trying to scan in all information but do not have it mastered yet.
The slim jim comes in different sizes for the various tons.
try http://www.awebgeo.com/SlimJim_Specs.asp

If I use an open system in my lake (I know I won't heat up 7 acres) how would I filter the water?

deaner,
That's exactly what I was looking for! Any idea what they cost?

Jersey
I went thru my file on geo thermal as I thought I had the prices, I am unable to locate prices. Telephone 1 888 277 2932 for prices. I discussed this with a lady in Louisiana that installed hers in a half acre pond but her house was well designed for effiency and the pond handled her unit very good.

Brettski, I'd go as big as you can afford. At least 4 ton unit. Much depends on how well the building is insulated as well as exposure, air infiltration, etc. The difference in cost between a 3 and 4 ton unit use to be only $300. As far as the well goes, I strongly suggest you consider 2 well tanks in parallel. Your well pump will cycle less often. Most all the wear and tear on the well pump is in the start up. Well pumps will typically draw three to four times the amps at start up. Put an amp meter on the power lines going to the pump, and you'll see. Any well installer will tell you that it's better to run the pump continuously with longer fill times, than constant cycling every 5 minutes. This cycling will eventually burn up the pump. The only way to accomplish that is to add pressure tanks.

Country,
3 - 4 tons of thanks! I have just spoken with the power company guru regarding geothermal. His immediate response was "if you can afford the upfront price, it is the only way to go". He went on to add: the only programs available is a $500 rebate on the system...nothing on the power rates. In fact, the current rate of .08 per kwh is about to top out at .09 in 2006 due to an increase. His only reservation about an open loop was the possiblility of the well drying up (thanks, but kinda obvious to me). Past that, tho, there are geo heat systems in the county and he pointed me to HIS guru at the power company...I have yet to call him, but it's on my list. btw, regarding the well, during my search for this property, I pulled the state well records. The 3 closest wells are all within 2000 ft and reported tests of 15, 15, and 35 gpm for one hour. This is a good sign?

Cut and paste doesn't work too good, but here is the spec sheet with prices. The model number shows how many tons it can handle in still water.

DESCRIPTION DIMENSIONS PRESSURE DROP VOLUME

SJ-02T 2’ x 6’ x 3/8” 6 GPM, Approx 5 psi 1.2 gal 55 lbs $ 1,486.00 28 lbs.

SJ-03T 4’ x 5’ x 3/8” 9 GPM, Approx 2 psi 2.0 gal 92 lbs. $ 1,991.00 46 lbs.

SJ-04T 4’ x 6’ x 3/8” 12 GPM, Approx 4 psi 2.4 gal 110 lbs. $ 2,195.00 55 lbs.

SJ-05T 4’ x 8’ x 3/8” 15 GPM, Approx 6 psi 3.2 gal 147 lbs. $ 2,736.00 74 lbs.

*SJ-08T 4’ x 12’ x 3/8” 24 GPM, Approx 8 psi 4.8 gal 220 lbs. $ 3,490.00 110 lbs.

a 3/3/06 dialogue, cut & pasted from another thread; transferred for continuity....
Brettski asks:
Ryan Freeze responds:

I noted (a couple of posts up) that I was gonna contact the local power company geo-guru. I did the end of Jan; some of the notes to follow.
Most geothermal (GT) in the area is closed loop, a few are open (pump & dump; P&D). The county will provide a $500 rebate for installation of GT unit. Also, the federal govt will provide an income tax rebate, based on a Bush bill signed in Aug '05. The state will also provide a property tax deduction. You fill out the forms once in the beginning and the deduction will be perennial. If I use a super-heater for the (electric) WH, they will provide the first WH tank at n/c and a 2nd (some folks do) at their cost. (They are a Touchstone Coop)...no breaks on electric rates regardless of loop design; first block is .08 kw/hr (smaller, usually consumed by lights, refrig, etc) and second block is .065 kw/hr. They feel this second block is reasonable and provides rate relief for the additional cost to run a 220v well pump to power a P&D sys. He noted that there is plenty of water in our area; an open loop should be no prob. He noted that an avg home sys requires 6 gpm min for GT on P&D (personally, I think this is kinda slight but I think he considers avg home as smaller).
I have already pulled the well records for 4 v recent wells, all within 2000 ft of our project. It should be a non-issue. I continue to lean toward P&D.

Brettski, Mid American currently cuts our Electric rates 50% from Oct- Mar,then holds at normal rates for the second six months of the year when using all electric in my home. I believe you will be very happy with the results of either the P&D or the closed loop. Sounds like some great incentives Good luck!

I just did a figure on the pump and dump and I believe my pond would hold this since I have good evaporation. The pond gets very hot in the summer so a closed loop would require a much longer run time. I find each of your thoughts very interesting ---thanks. I have a high capacity pump so 2 more tanks would decrease the run time sufficiently.

Is your pond spring fed or does it have a lining. If it's spring fed, the pond can take any amount of water you dump to it. The hydrostatic pressure of the pond equalizes with the pressure of the aquafer. In my case, I put in a winter heating season, over one million gallons of water, and my water level went up 3-4 inches, then stayed there. If the pond is lined, it's like a bath tub, so all the water you dump to it will raise the level, unless you have an overflow somewhere.

My pond is clay lined and I have a pump rated at 60 gallon per minute. I loose about 2 inches per day more or less because of evaporation. My pond held on fillup approximately 2 1/2 million gallons of water and we had a very big rain at that time also. I have a dip in the berm where it could over flow if needed. on a refil the other day I pumped for about 26 hours or 9360 gallons unless I figured incorrectly.

This is a really long post - sorry. Don't get me started.

I do Geothermal. In response to Brettski's request I am posting re:geothermal heating and cooling. I have been an HVAC contractor for over 25 years and we put our first geothermal system in about 22 years ago.

Some of the prior information is good, some not. A geothermal system first of all is not really geothermal - technically. A true geothermal system would be one that uses heat from deep in the earth, like the hot springs in Wyoming. A more accurate description is Ground Source Heat Pump. Not as sexy, but more accurate.

As Country Boy pointed out there are 2 types commonly installed - open loop and closed loop. Open loop is also known as "pump and dump". Open loop extracts water from the ground - then either absorbs heat from it or rejects heat into it - then dumps it. Closed loop systems circulate water (with antifreeze in it) in a closed loop in the ground. The water leaves the house and the fluid either absorbs heat or rejects heat depending on if you are heating or cooling.

All of my experience is with closed loop systems. Around my part of Ohio, it is not unusual to have problems with water quantity and/or water quality. If the water has iron and other stuff it it, maintenance of the water pumping apparatus is an issue. If you do not have enough water in gpm year-round, the system will not perform properly. We like closed loop because we avoid those issues. Not saying they won't work - I am guessing maybe 10 or 20% of installed systems are pump and dump - I just do not have any experience with them.

Closed loop systems can use a ground loop that is either horizontal, vertical or in a pond. (magic word - give that man a cigar). We have installed maybe 150 systems. Most have been horizontal as it is the least expensive to install. We use veritcal when there is not enough room for horizontal or the owner doesn't want us to mess up his yard too much. Ponds work great if they are big enough and not too far from the house. 200' from pond to house is a good number but it is always possible to go with bigger pipes and pumps if the pond is farther away - just doesn't always make sense economically. All 3 methods - horizontal, veritcal and pond if installed correctly will work just as efficiently.

Regarding the sizing of the unit - how many tons - that is not a casual consideration. We always use an industry approved method to size the equipment - ACCA Manual J - to see how much heating and cooling is needed. A smaller well insulated house in Illinois would not necessarily need a 4 ton system. More on this if you want it but I think you need an HVAC contractor who will calculate what you need and stand behind it (that is what we do). Let me know if you need more info on correct sizing.

We install WaterFurnace brand systems. We always install polyethelyne pipe for the ground loops. We have a special "iron" that melts the plastic and welds it at the joints - stronger than the pipe (burst). We test our installations as we put them in. Never had a leak. I would never use copper due to potential for leaks and future corrosion. Polyethlyne is the same stuff as garbage bags. Dig it up 40 years later no deterioration. As long as Polyethylene does not see UV rays it is the way to go. Priced copper lately? - they are stealing it as fast as we put it in.

As far as is it the way to go the short answer is yes. This is what I do for a living. I can give you the algebra formulas to compare all the different options you might consider for your home. Geo wins every time. Some examples"

Natural gas w/90% efficint appliance and $10/1000 cu ft = $11 per million btus into the house.(Nat gas wes 50% higher than that last winter in most markets).

Propane gas w/90% efficient appliance and $1,75 per gallon = $21.25/million btu into the house. (they are at about $1.99 per gallon locally here).

Fuel oil - 80% efficient - $2.50 per gallon = $22.32 per million btu into the house.

Electric reistance heating (elec baseboard, elec fan forced heaters, electric water heater, toaster, hair dryer) - if wither electric costs $.06 per kWh (local rates) = $17.58 per million btu into the home.

Geothermal (Ground source heat pumps) deliver 4 times the heat for one kWh vs. elec. baseboard, or a per million btu into the house cost of less than $5!.

As you can see, local costs for the electricity and the various fuels plays into it, but no matter how you slice it ground source heat pumps heat for less. Oh yeah, they also cool for a lot less - very important to our southern friends. Oh yeah, they also typically produce about 50% of the energy needed to heat water (at 25% the regular cost).

There are of course a lot of other things to consider. What is the "upfront" installed cost of the various choices? What local fuels are available? (nat gas not available in all areas). What is the energy load of the building ( a small load that does not use much energy reduces the effect of more efficient choices). Does the homeowner want air conditioning (believe it or not we have customers who do not want A/C. This reduces the value of geo as it is a heat/cool system and it uses rejected heat in the summer to heat domestic hot water). Do you want a tank (LP or oil)? Do you want combusition and the possibility of CO (Carbon Monoxide)?

And now the really serious stuff. What is the maintenance cost? Oil is an annual affair to keep it running efficiently. LP and Nat gas burn cleaner but still require regular maintenance to keep efficiency up and avoid repairs. Geo units are pretty much "plug and play" if designed and applied correctly. Kinda like a refrigerator. Or driving your car at 55 all the time. When we do "annual maintenance" on our geothermal installations, it is like going to the doctor when you are not sick. Check - ok, check - ok, check - ok ,etc. etc. Other than keeping the air filter clean, there is nothing to lubricate or adjust. So "life cycle costs" are much lower with geo.

Lastly - what is the outlook for energy costs? We have seen big run-ups in cost for fuel oil, LP gas and natural gas. Electricity, which used to be considered "expensive" to heat with is now suddenly an option worth considering. What does the future hold? Well electricity is generated mostly from coal which has nearly doubled in cost in the last 2 years (wholesale market). Most electricity generators and resellers are tied into long-term agreements that slow down their ability to raise prices quickly. But increased electric costs are coming. The electric utilities have a product that costs them more to produce, and the customer's other options have increased dramatically. They will be raising prices as soon as the regulators allow it.

So there you have it. Geo 101. Feel free to ask other Geo or HVAC related questions. I will help if I can.

Bravo Asleep...Bravo!
Very educational. I believe that you will find a very interested following within the PB forum. Many thanks for the dissertation.

Thank You AaTW. I am very interested. Is the system less efficient in a HOT part of the country like Texas? What are the up front cost caparisons? Do you drill a well? How deep? How could a horizontal loop help when the ground is 90 degrees at 10' around here? (may be an exaggeration but it is hot).

PFF - geo is very popular in Texas and very efficient. Geo will cool your home in Texas using a lot less electricity than a typical air-source unit. If Bruce ever sends you 12" Bluegill I want some too.

The up front costs to install geo are higher. The systems we put in are usually 3-5 tons for homes 1500-3000SF. Usually about $15K to $25K total for HVAC system installation but there are a lot of variables. - we sometimes do zoning, air cleaning, swimming pool heat, radiant floors, etc.


Air source heat pumps are very competitive with other choices ( I prefer them over gas and oil and I own one - yes they work great north of the mason-dixon line). A geothermal system costs probably about $5,000 to $10,000 more than air source (or gas or oil). If you are building with a 30 year mortgage the upgrade will cost you maybe $40 per month on your loan payment. It will save maybe $60-70 per month on utilities. Black ink from day one. You can make this analysis as complicated as you want. Black ink from day one is a reality.


If you are considering retrofitting with geo we charge more for that - it just take more work. A geo retrofit for a 2500 SF house might cost $15-20K. Often the electric service needs upgraded to 200 amps at additional cost ($2K).

I have found people get all hung up on the upfront cost and can't see the operating cost pays for it.
If you pay $500 for a refrigerator and a more efficient model is $800, and the lower cost model uses $1500 more electricity over its lifetime (about 20 years) which one is cheaper?

PFF - you can find out what the average ground temp is at 5' depth by asking your local HVAC contractor. You will have to ask someone else about drilling a well - my experience is with closed loops - no well required. If you are serious you need to find a local HVAC contractor with experience in geo. One way is to go to waterfurnace.com and select "dealer locator" or something like that.

Original quote "this really got my squirrel cage a turnin'. I second that! I just read this thread completely thru and I am still not sure what to go with. I am going to post some questions tommorrow about this, for now I've run out of time. Too many options. I hope Asleep at the Wheel is still around to advise & inform.

I have been living with my WaterFurnace for 2 months now. The meter reader couldn't get in my gate last month, so I will be able to give you some utility costs in a couple of weeks. Here is what I do know...I am cooling about 4500 sq.ft. with lots of windows and doors with a 6 ton unit. It has been 100+ degrees here for the last two weeks, and I can make it as cool as I want inside.

My house is about 220' from the 6 acre pond, and I am running a closed loop. There is 3000' of 1 1/2" plastic pipe coiled up on the bottom of the pond. The coils are tied up on a "sled" about 8'x14' that the guy floated out and sunk. I have two tiny little pumps, no bigger than your fist, that circulate the water through the loop. The system cost, including ductwork and everything was a shade over $20k. I'll let you know if it was worth it when I get the bill, but so far I am very happy with the system.

Jersey why did you decide on the closed loop system verses the pump and dump? I saw in an earlier post you ask about pump and dump using the pond itself was this an option? I don't currently have a well I'm on rural water coop so that is why I started considering the closed loop pond system to begin with and my pond is only about 15 ft from my door step. Your input would be greatly appreciated sense you've been there and done it already. Also tech questions. How big is the inside unit, will it fit in the same foot print as a conventional vertical airmover unit? What routes indoors to the unit itself? The poly pipe? I do not have a basement it will have to go up stairs on the second floor.

Rockytopper,
I went with the closed loop for several reasons.
1) I don't want to pump silt or fish into the system.
2) I don't want to take care of a filter
3) It uses a much smaller pump than an open loop would require
4) My HVAC man told me to.

The unit is no bigger than a standard furnace, and there is no outside unit at all. The supply and return tubes are about 1 1/4" and run from the indoor unit to the pond. Again, there is a 3000' loop on a 8'x14' frame in the pond. The 3000' loop is actually six 500' loops in parallel. My tubes go from the unit, up and across the basement ceiling to the other end of the house, out the wall and down the side of the house, and underground to the pond.

The red tubes carry domestic water through the "superdeheater". Yep, that's right. A superdeheater. It catches the heat that would otherwise be wasted, and circulates it through my water heater. It makes enough hot water for my whole family of four. I have my two 80 gallon water heater circuit breakers turned off, and we have plenty of hot water. 160 gallons of it to be exact. The heat is taken from the hot side of the compressor. I have radiant heat in my kitchen and master bath floors. This winter, I am counting on this superdeheater to warm these floors.

Sorry for the quality of the pictures. The two white things are the loop pumps. One pushes and one pulls. They are about the size of your fist.

Since I don't know what my power bill will be yet, I have to say the thing that impresses me the most about it so far is that it can cool this 4100 sq.ft., half of which has 20' ceilings, so well. It acts like it is bigger than 6 tons. The blower in it uses a DC motor with 12 speeds. It ramps the speed up and down depending on how many and which zones are calling for cool. Pretty neat.

I would tell anyone that asks, if you are going to stay in your house for a while, and you can spring for the initial cost, then get a WaterFurnace. I figured to break even on it in 5 years, but I didn't even count the free hot water. It is a very well built machine.

Very nice report, Jersey.

Jersey,

Thanks for the details on your Geo system, that's next on our "major improvements" list. How deep do the pond loops need to be?

Thanks,
Chip

I think that depends on a lot of things. How big is your pond, how much flow goes through the pond, how big is the geo system, stuff like that. My loop is about 5 feet to the top, 7 feet to the bottom.

Thanks Jersey you've sold me and answered a lot of questions. Sorry for the late thank you but the system has been to slow lately.

My neighbor has the same 6 ton unit I have, plus a 3 ton unit. His loop is buried horizontally in the yard, not in the pond. His house is about the size of mine, but I think he cools more of it. He told me yesterday that the highest electric bill he has had this summer is $215. He keeps the t'stat at 77 all the time.

My pond water temperature is 97 degrees. I do not know if this is too warm for the cooling cycle? I have thought of dumping into another shallow water if the pond is too full to handle the geothermal discharge. I would rather use the Slim Jim and the wmall water pump. I have not read any thing on this. I did talk to another person in the hot south that used the slim jim and made out very good, but I think the little pump would need to run for a very long time. Any thoughts on this topic? My house is 2000 sq. ft.

I wish to change my previous statement that I wish I had put in an open loop system. No maintenance of the closed loop is a better deal IMO. Against the GT mfg. recommendations I have installed bottom diffuser aeration and my bill has only increased about $30 running the aerator 24/7. This is about what I expected to run the compressor. If I want to fill the pond I could always put in a well and fill it, no reason to spend the money to pump groundwater in years when it's not needed. My system on a new build only cost about $1100 more than a conventional heatpump/electric system.

Ryan - Are able to measure the bottom water temperature near the loop in your pond?.

Deaner,
The way I figure it, it is still easier to dump heat into 97 degree water than it is 97 degree air as a conventional system does. My installer said he had seen problems with the Slim Jim not transferring heat as well as it should. And they certainly are expensive.

Bill, my thermometer only has a 4' lead and I'll need to get the boat out to get out that far but I'll see what I can come up with. Maybe I'll be able to get some underwater video at the same time. I've been curious about the bottom temp as well but the Vertex with two lift stations is probably turning quite a bit of water in my now <half acre pond.

Hi all...
Wondering what advice I need to hear about my geothermal project.
Our home is aprx 3400 sq.ft (livable space). The geothermal rep. talks about an 8 ton unit. He says a 4 ton unit will work but it will need to draw more emergency (electric) heat than the 8 ton unit and so recommended the larger size. He says it will be about 400% efficient. Sound right?

- The original portion of the house is an older two story farm house with an addition of 15'X30' and an addtion of 30'X40' [there is also a 16'X14' 4-season room which is currently coooled/heated when needed by a 'hotel' type unit].
- Planning an open pump and dump system into a farm pond 1/4-1/2 acre)
- The existing water pump is 1/2 horse -- they talk about upgrading to a 1 1/2 horse variable speed pump with a small water tank bladder... Is it useful to also have a seperate water tank? to reduce wear and tear on pump? to save money?

Thanks for any input!

Other points of concern:
I understand I need to aerate the water before it dumps into the pond... but how to do this? Since the pipe carrying the water will need to be above ground before it exits into the pond (so it aerates) how does this keep from freezing?

Is it possible to have the pipe bend upward through a pile of dirt and rocks so it then runs down the rock into the pond?... thus making a waterfall. Or will this cause a freezing risk during times the geo unit may not be running? In IA water CAN freeze very quickly.
If I'm not being clear let me know!
Thanks!

Chris4:

Perhaps two different outlet methods, depending on the season, could be used. Aeration is not nearly as critical in the Winter - cold fish use less O2, while cold water holds more of it in solution. So in the Winter use a straight dump that is 100% freeze-proof.

When the weather is warm enough, aerate the water before releasing it into the pond. Yes, dropping it over/through a pile of rocks would help aerate it. Check out Cecil Baird's "Packed Column" well water aerator here. Dropping it like a waterfall through a rock pile might not be quite as efficient, but would be more aesthetically pleasing if you are not as keen on 5 gallon buckets as I am.

Ejecting the water through a "sweeper nozzle" juts below water level could also be used, perhaps in colder weather than a rockpile drop. These would produce Bruce Condello-style "horizontal aeration" - somebody (maybe me later) can link to that thread for an explanation.

Condello's Horizontal Aeration Thread

You're looking at a lot of potential maintenance down the road with a pump and dump system. I think the closed loop system with the exchanger coils sunk in the pond is by far the better and less expensive choice.

Sure there may be a filter to clean (my geo guy says that this is not too often). The closed loop is not as efficient, has its own concern that it could get buried in the pond, and has more up front cost involved (not as much as burying the loops but still more cost). Plus... I don't know whether a pond is feasible without a pump/dump from the geo unit.

What maintenance are you speaking of?

Just installed a split zone WaterFurnace last Fall, one 6 ton and one 4 ton for almost 5000 sq ft. Open loop saved me $9000 over closed loop option (earth bury). I can replace alot of pumps and filters for that, plus open loop is more efficient. Ruled out sinking exchangers into pond because there is a chance of supercooling. Heard all the arguments for and against. I chose not to gamble with my fish.

Geothermal was the best decision that I made while building this house, hands down. I'm total electric, it's one of those houses when you turn one light on... You've just turned on 20! Aerators 24/7, home theatre 10/7 (unfortunately), but I haven't seen a bill for over $200 yet. I take that back, when it was first installed they installed the dump line below the water surface and it froze. The heating bill on a month of emergency electric default was $1000! Quickly rectified.

Pond has been at full pool all Summer. I could go on but I am sure you get the picture. Good luck Chris4, Geo's the way to go!

I also went thru all the whys of geothermo and after much research both here and elsewhere, meeting with several installers, I went with the closed loop in the pond. No regrets.
5 ton unit for 2500 sf living area. Works great. Still newish and watching my electric (which like all else has gone up with the economy the way it is). Looks like I'm running about $30-$40 more a month electric but compared to the LP costs--this is a HUGE savings for me. Payback is 5 years. After research you will learn that components between top notch brand and competitors are not much different, you really need to look at the overall warranty and choose an installer that will be there when you do require maintenance. Our installer was SO knowledgeable and not a hard-sell salesman top--he impressed us tremendously and was a BIG factor in our choice along with the fact that they had done a lot of geo installation to begin with. Closed loop vs open loop, there are a lot of pros and cons for both, the problem with open loop are the filters, silt etc--one lady in town has that and has nothing but problems. Why did I choose closed loop?? I had a pond, it is more efficient than your other choices, I didn't want to burden my existing well or dig a second well, and I didn't want my yard torn up. But here are some pictures to share for those who are looking into it. You will learn that it won't hurt the fish, that it can be brought to surface really easy (they just withdraw some of the liquid from the lines and it floats back up. The ideas of hooks in such a thick pipe has never happened by our installer in 20 years; if it did, no problem to fix. You need to research, researh, compare, compare, price, price, ask, ask--negotiate. There were incentives by the State here of $400 per ton that I took advantage of, most utility companies have some rebates--mine didn't. Ryan on this thread was of much help to me.

8 tons? Sounds way too big to me. I have over 4000 sq ft of space and my 6 ton unit is plenty big enough. But I don't have the heating requirements you do. Why not go with a closed loop system and not worry about freezing?

I have a 5 ton in a 3500 sq. ft. with 32 windows, 5 exterior doors, 2000 sqft basement, on top of a hill in flat country. My electric bill has hovered around $160 the past six months. I installed the bottom diffuser aerator against the my Mfg. recommendations and have seen no unexpected bill increases except for the $30/mo for my aerator that runs 24/7. All I have to worry about is blowing out the reusable air filter every month or so. My geo system only cost $1100 more than a standard Electric furnace and heat pump. A well based pump and dump would have cost more in my case because they would have had to drill larger and deeper well.

As far as effeciency of dump vs. recirc., from what I've read it can go either way by 10% or so depending on air temp, groundwater temp, and how many ft of head you have to pump the water. In a closed loop you're probably looking at running a 1/3 hp recirculator vs. the 1.5 hp well pump, smaller is cheaper to replace if needed. In the past, recirculating components have outlived pump and dump components because of iron and other minerals causing parts to wear out.

A pump and dump system opens you up for more excuses, such as component wear due to water quality issues, for a manufacturer not to warranty their product compared to a sealed system. If you need the water to keep your pond filled then the pump and dump may be your only option obviously because a closed loop in the bottom of a dry pond isn't going to help much.

I've read about people switching from pump and dump to closed loop due to problems but never the other way around.

Supercooling? I have never heard of this actually happening with any residential system.

Dumped heat heats my water. You may have to request that be hooked up.

Is it me or is this thread whacked? It's very, uh, w i d e.

too bad, too
it's a keeper
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...moderators...???

I think it's a great thread. I like reading about geothermal systems. What are you guys talking about???

It's a good thread for those who have a pond and want to do geo-thing with it. Keep it going; it helped me with my research and decision to go geo.

Please allow me to re-phrase what (I believe) Jersey and I were trying to say.
Theo answered my request for a moderator. He went back and re-configured a set of posted pics (on the previous page) to narrow the very wide view so that a horizontal scroll bar wasn't required to read it.
You're right MarkECIN...it's a fabulous thread and well worth keeping and growing. Jersey and I couldn't agree more.

Since there's talk of giving geothermal it's own zone. Should we be calling it a ground source heat pump?

It seems the term geothermal is becoming more closely associated with deep well steam power generation than residential HVAC.

Geothermal is easier to say, sounds cooler and will be a hard habit for me to break.

I say we stick with "geothermal" . Let the multi-megawatt power plant guys change their terminology if they have a problem.

Whew! I'm glad that's taken care of...

Of all the things I did when I built my house, the Water Furnace was by far the best. I will get payback in three years.

Oh Ok now I get it. I have a 24 inch monitor so I didn't see the w i d e.

And the post didn't seem wacked and I know wacked.

Ok, y'all...need your opinions again. First full winter with the geothermal (closed pond loops). We had the maintenance man come out and check the settings (he has to make some calls and get back to us, been two weeks). One thing I'm still not sure of, when should 'heat strips' come on? Any of you know? This last week it's bee minuses and low one digit and even though we have the thermostat at 72; it shows 63 and we do believe the heat strips are kicking in a lot (as we notice the lights dim). Any of you with geothermal have gone thru this??? I know its pretty complicated settings etc. Bottomline, the house is warm and my electric bill is only running about $30 more a month because of the geothermal unit.

I'm still learning how these things work. I didn't even know about the defrost cycle until a month ago when I contacted a geo-contractor to talk about their power draw. I was hoping to some way, some how, have the option of a geo system on a decent solar power system. When he told me about the power draw when the coils are defrosted, my plans also defrosted.

I also wondered if geothermal could be run off solar....what I see now, I doubt it. Our biggest complaint is we notice the power draw...the lights get dim (I haven't checked with the electric company as far as what their thoughts might be). I know it's real complicated with the settings, stages etc. on the thermostat and on the geothermal units but we just think the heat strips should not be coming on as often (so we feel it's in the settings). We're waiting on the installer's pro to get back but in the interim we are puzzled. We put the strips in as 'backup' but this geothermal stuff is pretty complicated.

It probably depends on region you are in. I was thinking about solar source heat pump also but the cost and expected technical difficulties pretty much killed the project before it started. At the end we decided on classic GT instead unproven, exotic and unnecessarily system.
We are in south central Iowa and have Waterfurnace geothermal in operation fourth year. Our "fluffed coil" heat exchanger contains about 2500 ft of pipe and is in our pond about 300 ft from the house. We have 5 ton unit (5 kW) and heat about 4000 sq ft by floor heating. Our last month heating bill was 97 dollars for 2150 kWh.

We didn't have enough water in the pond first year so about half of the heat exchanger was above ice. Inlet temperature dropped to about 24F and return to 21 F but the house was still reliably heated. I think that floor heating is primary reason for low heating cost. We have set temperature entering the floor to 100F so the required temperature differential is much less than for forced air.

Ladia,
Did you set pex tubing into a slab, or are you running pex under a wooden subfloor?
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(edit)
Welcome, Ladia! Are you also a pondmeister?

I think Blaine has a geothermal system in his house. Hopefully he can jump in here and discuss this.

My hubby believes that any time you have that much power pulling where it keeps lights in house dim--it isn't good. (He says that isn't good on motors and things). We really believe it happens because of the heat strips or maybe it's because the geo runs harder in the winter to keep up vs summer. I just thought that it runs all the time and there would be no difference. I'm hoping someone has noticed same with their geo.

Yes,the PEX with oxygen barrier is in the slab.

Is this the aircraft hanger house?

When the heat pump starts there could be noticeable voltage drop for few seconds. If the lights remain dim during the HP operation you should investigate why. It might be bad connection between the breaker panel and the transformer or the cable isn't sized properly. Either case is potentially dangerous in the sense that the bad connection or the undersized cable can overheat and start fire. The heat pump shouldn't take more power than a stove. Heat strips, on the other hand, can take significantly more.
We have geothermal unit that draws about 5 kW when running. We don't have heat strips. Our lights dim for a fraction of a second when the unit starts only. Our transformer is about 35 ft from the breaker box.

Thanks. Will call the geo man again, tired waiting for him to come back with answer. We, too, feell it is dangerous.

Make sure he is an electrician. The geo people are usually plumbers. Your problem might be located out of your house. The heating just made it apparent. They need to measure voltage drop when the heat is on and find what and where causes that. It might be potential fire hazard.

Thanks, will advise what we find out.

I have a 6 ton WaterFurnace heating almost 5000 sq ft. This past week, it has been in the teens at night, and the unit runs a lot more than normal, as expected. I disconnected the heat strips because I don't want them to come on. On my system, the heat strips will come on anytime the thermostat is set more than 3 degrees warmer than the room temperature. I don't want this to happen. My electric bills stay under $100/mo.

Mark, we had a similar problem when our system was first installed. It was August, and I turned on the heat just to see if it worked. It didn't. It turned out that the company that installed the system used the wrong type of thermostat. Actually, they were aware of the problem an had just installed one temporarily so that we would at least have A/C while waiting on the right one to come in.

A light activates on my thermostat when the electric element comes on. It has been on often the past couple of weeks with temps consistantly below zero but I have never noticed lights dimming for any reason.

IME lights will dim when ANY electric load is marginal for the electric service.

Jeff, thanks for the intro a couple of days ago. Sorry, just got around to checking this out. I do have a split zone Waterfurnace system. If I remember correctly, one unit is four ton and the other is two. I decided to go with the open loop system because I was fearful of my fishies getting a little too chilly in the winter and was supposed to be more efficient than closed.

$97 electric bill sounds pretty good though, mine was $200 last month for about 4000 sq. ft. I haven't noticed prolonged light dimming and have not seen the heat strip indicator light on over the past 10 days. I have been paying attention.

One thing that I can tell any of you that suspect emergency heat strip activation... You will definitely know it when the bill comes! Mine was installed just before last winter. Unfortunately, they installed the dump pipes below the surface of the pond. Pond froze, then shut down water circulation. System ran all winter on emergency heaters. Bill averaged $800 to $1100 every month! Yes I ended up getting reimbursed every dime.

How else can I help?

Has anybody attempted and/or succeeded in installing a geothermal HVAC system as DIY?
If not, has anybody witnessed the installation and willing to offer personal thoughts regarding the difficulty level for a DIY project?
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For the smaller, tight, well insulated pond home we are dreaming of, I would love to try something like this.

Brettski,

If you have a sustainable watertable, look into the open loop system. My opinion is that there are more advantages than disadvantages compared to closed loop. This starts with a fraction of the install labor & material costs.

Another consideration might be an air-to-air heat pump for less labor and costs. I have a carrier heat pump for my 3 car garage and bonus room above. Can't tell you how good it is or isn't. I have only started the system a couple of times since it was installed 15 months ago.

Blaine, if I get an electric bill like you're getting--you better know they will pay! Ryan, we don't see an indicator light for letting us know when the heat strips kick in; however, if we turn them on manually, the whole backdrop turns red on the thermostat. Geo people coming back on the 27th; hope to get this issue resolved (don't want the house to burn down). My other option if they don't get it fixed is get another electrician to look at it. It just isn't right that the house lights stay dim like that.

MarkECIN,

My thermostats are Honeywell touchscreen style VisionPRO's model TH8000 Series. When emergency heaters kick on a five petal daisy shaped symbol illuminates in the upper right corner of the plastic frame around the touch screen. It can only be seen when illuminated.

Another way to know when emegency heater comes on is to look at the zone control circuit board mounted on the front of the air handler itself. There should be 5-6 red LED lights on the right. If the one under "AUX HEAT" is illuminated, Well...

Do you really only have $100 monthly electric bills? How many sq. ft are you heating? Makes me wonder if I have a problem at $200 per month.

Blaine, my last electric bill was from 11/20/08-12/30/08; 40 days; and 1,450 kw. We are heating 2500 sf living area, (cathedral ceiling in two rooms) and we have the temperature set at 72 degrees. Our kw avg usage is up 38% roughly so I'm going to say geo cost us an addl $40-$50 a month to run vs what our electric bill used to be.

Our thermostat is a ClimateMaster brand; Mark is more familiar with it than me (I won't touch it ). It would be nice to be able to tell from the thermosat when Aux Heaters kick in and not have to go down to the basement. We just want to make sure the Aux Heaters aren't causing the dimming problem...not to mention, I had concerns about the electric bill until I got the recent one...will be interesting to see the next one is though as we have had minus 18 and single digits a lot the last couple of weeks here. The geo people are coming out on the 27th and want to check their settings etc before sending out the electrician.

Other than that, we do like what we are experiencing with the geo overall...the house is a lot more comfortable, we keep the termpature higher than we did with LP (68 degrees); definite $$$s savings and it will pay for itself in 5 years. We thought maybe I would find it uncomfortable with the fan running constant with air flow, but honestly, it's not noticeable and I must say, my sinuses seem to like it. I'd recommend geo.

ClimateMaster huh? Funny you mention.. I happen to be having lunch in Fort Wayne tomorrow with ClimateMasters VP of National Sales. Kind of a networking meeting. Anything you want me to ask him for you? Need to know by 9:30 AM, that is when I get on the road.

Yes, please...his thoughts....
1. How do you know when the heat strips are on?
2. Should the heat strips be dimming the lights in the house whereas they stay dimmed?
3. Should the heat strips not run if it's 20 degress outside (shouldn't the geo be keeping up)? We think they're coming on.

Thanks. d

I'll ask him. Can you PM your telephone number in case he needs more info? I'll PM you my cell #. I'll be on the road between 9:30 and 11:30.

I have a Climate Master heating over 4K sq. ft. if you're counting the basement. All electric, my bill has hovered between $100 and $150 every month year round (including the pond aerator for three seasons) except December's bill.My better half and daughter where home all day and the thermostat was set at a sweltering 74 deg. Bill for December was a little over almost $250! Still a lot better than the farmhouse that was running $5K/yr in propane alone.

I sure like the idea of these geothermal systems. Keep the info coming!

Ryan, that's awesome savings! I should get the electric bill that covers most of Dec and first of January pretty soon here. I was running over $3,200 a year (and keeping the house at a cold 68). I didn't see it getting better. I figure my savings will run $2,700 to $3,000 a year -- of course, things always go up it seems.

MarkECIN,

Sorry for the delay. Unfortunately, there were way too many unknown technical factors for him to be able to diagnose at the lunch table. Things like calculated BTU loss for house, size and model of geo. unit, electrical service capacity, house wiring, etc. etc. Also, I didn't realize that my guy was in the industrial division, not residential.

Sorry that I couldn't be of more help but it sounds like you are on the right path by scheduling the service call for next week. I would be interested in knowing how it turns out.

By the way... My electric bill more than doubled to $480 for the last billing cycle. Ouch! I didn't notice the emergency power being activated at any time. Granted, it has been cold in the midwest over the past 4-5 weeks but has anyone else seen dramatic spikes in their energy bills for the previous billing cycle? Especially interested in responses from geothermal owners.

I'll know soon enough...electric bill should be forthcoming and the geo guy Tuesday. Thank you for asking though, I'm always listening to what others have problems with.

As I reported before, we heat about 3600 sqft, single floor no basement and our heating bill is usually less than $100 even in December and January. Total house electric bill is usually around $250. Typical HP has about 400% efficiency while heating strips have 100%. Therefore heating strips of the same heating power as the HP will quadruple electric power consumption for the time they are on. Our utility in Iowa charges 4.1 cent/kWh for the HP and 11 cent/kWh for the other power consumption. If your heating strips are connected to the "other than HP" meter you will get charged the higher rate.

Well it is an aircraft hanger in the sense that the garage door is 36 ft wide and the garage can accomodate pretty much any 4 seater or smaller aircraft. To have an airplane and own landing strip was my dream since my childhood and it is my retirement project. Therefore we decided to build an aircraft hanger and live in it.

http://www2.snapfish.com/thumbnailshare/...QHglfmUzSRtpw--

Very cool retirement project.

Ah! Blaine, we got answer! Thanks everyone, now here is what we found out about the problem we were having with the goethermal system.

The geo technician came today and checked everything out again. We found out we couldn't hold 220 volts with everything on in the house. So, the electric company, was called by the geo tech who talked to them and the electric company came out and put a larger transformer by the road. That should take care of it.

Heat strips we found out come on two at a time and/or four at a time--we didn't know they work that way (I think someone in a much earlier post noted same). Now don't ask me anything about the Phase I, II etc--over my head!

I really, really think POND BOSS needs to add a section for Geothermal (for all us pondmeisters to share our wealth of knowledge (or lack thereof). Others asked and I'm asking too.

Were the heat strips coming on because of a voltage drop, or because the compressors were unable to keep up or maintain efficiency due to the insufficient current? How many AMPs of service are you set up for? 200? 400?

I like the idea of a dedicated forum for geothermal discussion.

200 amp service. My hubby said the geo wasn't keeping the house warm enough so the strips would kick on (thus what they are designed for). Guess, we'll just have to monitor it some more (see what the next couple of electric bills are). Really nothing in our thermostat for letting us know if heat strips on. The lights aren't dimming anymore (it was really noticeable before today and we were highly concerned about that).

In forced air system the heating strips come on when room temperature is several degrees less than SP. In example it might happen when the program increases the SP in the morning. The strips can heat the air to much higher temperature than the Heat pump so that way the system is able to increase the room temperature rapidly (take the chill out). Other possibility is to size the heat pump for about 80% of maximum (it is cheaper) and cover the deficit by the heat strips. The reasoning is that the extreme heating demand is relatively short and it is more cost effective to use cheaper heat pump and pay little for direct heat.

To answer your question: The heat strips use a lot of power and therefore the combined load of heat strips and the heat pump overloaded the transformer causing voltage drop.

Purposely undersizing the heat pump doesn't make much sense to me. Geothermal systems are most efficient when they are allowed to maintain a constant temperature. Programing a thermostat to cycle temps up and down around home activity actually will increase your electric bill. If the geothermal is sized right then the heat strips should rarely if ever activate.

Theoretically, an upgrade to the transformer only succeeded in treating the symptoms. It didn't fix the root cause being simultaneous heat source demand caused by an undersized heat pump. The electric co. just made it easier to draw more power. I thought that the whole idea of geothermal was to utilize the constant heat of the earth and cutting the energy consumption by reducing or eliminating electrical resistance heat generation.

I just don't agree with the techs diagnosis as I understand it. That would be like a recommendation to increase the throttle for a ship slowed by dropped anchor. Just my two cents for what it's worth. I was just looking for a little more clarification of the techs' diagnosis.

Please explain to me what an undersized heat pump would be. The only thing we ever heard size-wise was we have a 5 ton unit. We talked to a couple of geo people before we did this and all they ever talked was tonnage.

Much of this equation is determined by the how well the house is insulated and how tight it is.

Heat pumps come in various sizes from small units for home to large units for apartment buildings.
The reasoning is that smaller heat pump is cheaper, requires smaller less expensive heat exchanger and cycles less at warmer temperatures. Supplemental heaters operate only limited time during temperature extremes. This is European customary set up.
We have 100% sized unit that cycles during warmer weather and runs almost constantly during very low ambient temperatures. We also have supplemental heaters in the heat accumulator but the breaker is turned off already for several years and the heaters will be used only during malfunction of the HP.

Undersizing HVAC doesn't make long term sense for the consumer, but is common enough as some contractors (IME, YMMV) propose a system smaller than what should be used in order to submit a low bid.


I agree, but then that IS their business. All they can fix is their electric supply - not correct any sizing problems with the geothermal HVAC.

I agree with what you said Theo. However, the diagnosis was coming from the geothermal tech. MarkECIN said that the geo tech called the electric co. to arrange transformer upgrade that will handle the excessive draw caused by simultaneous heat source demand. I would think that a proper diagnosis would be to find out why the system is regularly demanding emergency heat (heat strips). The fix would be reducing or even eliminating that demand.

The math doesn't add up for purposely under sizing the geo unit allowing the emergency heat strips to take over in extremes. It takes four times the energy to run them. I guess that I could agree if the emergency heaters were activated only a few hours a season but I don't think that that is even close to MarkECIN's demand. The only other factor would be the additional cost of a properly sized system at the time of installation but I would be shocked if that cost is even close to what running heat strips on a regular basis year after year would be.

Once again, Brettski is right. Proper sizing goes way beyond sq. ft. of the house. Other things to consider but not limited to are house floor plan, multi-level, average outside temperature, average wind speed, insulation integrity, temp preference of the owner, shaded or full sun etc. etc. Unfortunately, many contractors don't take many of these factors into consideration when sizing and designing a system. It's the consumer who loses in the end.

One more thing my hubby was wondering about...the geo tech stated that the temperature coming into the unit was in the 20s whereas ground loops are much warmer coming in. The unit cannot build as much heat with 20 degree water. In essence this would make one think that ground loops are much more efficient contrary to all what I've read and heard that pond loops were. Thoughts? d

Ahhh. Now we are talking about potential root causes. First of all 20 degree water is frozen solid. If the fluid really is 20 coming in then I would question the length of the of the loop. Regardless, that has to be the major contributing factor to your issues. My non-expert understanding is that an open loop is more efficient than a pond loop and a pond loop is more efficient than a ground loop.

I'm starting to worry a bit about your geothermal tech. Like Blain said, the water is definitely not in the 20's. If you have a closed loop, it is on the bottom of the pond, so it is at least in the mid 30's or better. I disagree about the efficiency of an open vs closed loop though. In a closed loop you only have to circulate water, but in an open loop you have to lift water. Then there is the filtering problem.

I understand slightly undersizing the system. An undersized system is more efficient and costs less. That is up to the point where you cannot maintain comfort on all but the most extreme days. It sounds like you may be slightly undersized on cooling, but way undersized on heating. Why don't you unplug your heat strips (like I did) and see if the geo system can keep up on its own? Don't turn the thermostat down while you are away.

The company has done many ground loops and we're only their second pond loop, but they are a reputable company. However, I agree with you and believe there is some 'learning' happening here with the winter side of things (the unit was fine during the summer as far as I cold tell). Mark keeps throwing me questions to ask y'all. IMO the unit size etc and other than the problem with dimming we had, it is operating pretty close to correct. Like you said, without disconnecting the heat strips, I'm not convinced. I will dig up the literature on size etc; this may give you a better understanding of the unit itself (and that staging etc is SO over my head). Our house is well constructed with high R ratings in the walls and ceilings. It's been SO darn cold here this past month. I know it is 5 ton and we have 500' (5 loops) sunk in the pond for sure. I'll get back with more info.

It's possible the transformer was undersized. Need to measure amps and voltage drop to diagnose properly. The electric company would probaly do this before swapping the transformer.

Blaine has touched on this but I don't think it's been answered, do you leave the thermostat on one setpoint or is it programed?
Do you manually adjust the thermostat up and down based on activity or comfort level?

I have an air source heat pump that I installed a few years ago and had a very hard time convincing the wife to leave the settings alone.

They (HVAC Company) should have conducted a "Manual J" to determine the required heating and cooling load for your house. I bought some software and did this myself when I installed our system. It's a pretty good experience especially for an older home as you can change paramiters (like increased insulation) and see the effect imeadiatly.

Again, how could the electric company undersize a transformer for a house when the installed systems are designed to be more energy efficient than the norm. I doubt that they gather all of the energy efficient data for each house before they choose transformer capacity. If they did it wouldn't be an issue. MarkECIN, you don't have any out of the ordinary high energy draws outside of HVAC that would strain normal residential service do you?

TJ, Leave the thermostat in one set position. If you must adjust up or down, do so in no more than 2, maximum 3 degree increments. This will keep the heat strips or AC from kicking in for faster recovery.

Don't know Blaine, we built the house new 10 years ago, pond 3 years ago and put geo March08. We keep the thermostat at 72 constant. 2500 living area, two people, nothing connected to the house electrically that is out of the normal (washer/dryer/fridge, the like). Not unless the neighbor has a line coming to the house and stealing electricity (just kidding). Seriously, all the calculations for determining heating and cooling capacity were done beforehand; quite a lot of work (i believe this even had to be submitted back to the State for the geo rebate money)...I may have a copy of it.

Yesterday, when the tech spoke with the electric company, the electric company was out within an hour to put in the larger transformer. What I don't understand is why this wasn't part of the front end test to "force a failure" (i.e. dimming of lights) and the transformer issue would have been caught back in March.
You know that is bad on motors etc.

Fairly easy to undersize it I would think if the house had gas heat originally. Those heat strips are inductive so a fair bit of inrush comes with the package.

I know this may be comparing apples to coconuts, but I have a 5 ton WaterFurnace and over 5000 sq ft. The installer said the pond loops need to be 600' per ton, so I got 3000' of loop. If you really have 500' of pond loop, this may be your problem. You may want to make a call to your system manufacturer and see what they recommend.

My last furnace ran on natural gas, so the first thing I noticed about my geo system is that the air coming out of the registers is not nearly as warm, and the system runs a lot more. My installer told me to expect this from any heat-pump, not just a geo system. That's one reason why you want to leave the thermostat alone. I would still suggest that you disconnect your heat strips, set the thermostat, and see if this works for you. Of course, in single-digit weather, you may want to wait a few days to try this.

Jersey, I got the footage screwed up; your number more inline (cannot find the exact footage in my paperwork yet). But this picture gives you an idea how much was sunk. I have a Carrier GT-PX Geothermal Heating & Cooling System (Two-Stage Puron Series)/ AG Series Electric Heaters and ClimateMater Programmable Thermostat. I found all that other data (the analysis stuff, etc but that is SO out of my league). I think we are OK for now other than the heat strips. I may do as you say and call the manufacturer direct. Thanks. d

Inlet fluid temps in the 20s may point to inadequate insulation/burial depth of the lines from the pond to the house. How far is the pond?

30 ft most, pretty deep except for a small valley section by the house. In pic you see guy on left going downward, that would be the low area at the bottom of like the levee.

The temperature should be above 34F even in the winter. Return should be about 2 degrees less. Check the pressure in the loop. Pressure in my loop is about 60 psig in the winter and 80 psig in the summer. The pumps are designed for pressurized loop and if the pressure is low they might cavitate. Another possibility is that the loop wasn't properly purged of air. The guy who installed my loop brought different pump when they were filling the loop and explained to me that the circulation pump will not purge air out of the coils. I had small amount of air coming out of the loop for about six months after it was installed. I could hear the circulation pumps chatter every few minutes as the air bubble passed trough them. Therefore I decided to install air trap to bleed the air out. I replaced one of the elbows with a T and sweat in about 3ft of 1" vertical pipe with a small ball valve on the top. Then I kept venting the air until coolant came out. I repeated the process until the pumps got consistently quiet. I also used the new pipe for a pressure gauge installation.

Would you say the depth is below the frost line? Did you notice if they isulated the pipes?

I looked up the equipment you have and this is a very nice setup!
According to one source I found the heat pump is actually made by ClimateMaster. If that is correct, here's a link to the installation manual.
http://www.climatemaster.com/downloads/97B0045N01.pdf
And a programable heat pump thermostat
http://www.climatemaster.com/downloads/ATP32U03.04.pdf
If this is your t-stat you have a fair amount of control over the heat strips through this interface.

There are two possible modes (algorithims) for the control loop, "Proportional Integral" or "Differential". Proportional Integral is the default mode. The installer would have set this option.
If the control loop is very "tight" there will be very little deviation from the set point but the system may need to use third stage to keep it in the loop in the time alloted by the algorithim. This may be what you're seeing since your electricity use seems very resonable. I'm thinking the heat stips may be energized for a vey short amount of time to keep it in the loop.

You have a two speed compressor so low speed is stage one, high speed is stage two and high speed with the heat strips energized is stage three.

You can control the amount of time the system has to meet the heeting demand with the heat pump cycle through the "Smart Heat Staging" option. I would try increasing the time interval to see if the system can meet the demand with stage two of the heat pump cycle.

"SMART HEAT STAGING
This will control how the thermostat to engages 3rd stage or auxiliary heating when needed. Options are ON or OFF. Default is OFF. When the option is set to ON, the time range for this option is 5-120 minutes in 5 minute increments, if set to ON. 5 minutes is the default time. This is the minimum amount of time after temperature conditions for activating auxiliary heat are met, before the electric heat is engaged."

Hi everyone. Nice discussion! I'm in N. Central Indiana, about 30 miles SW of South Bend. I had a company last Fall come out and quote a Geo system for the house, and I'm not 100% confident in their service. It took them a bit over 2 months for them to come back with a quote, and I'm wondering who else in N. Central Indiana I could call. My biggest concern is the electrical rates and the actual payback time. I have Nipsco as a supplier, and just got a notice from them about an upcoming 16% jump in rates.

While the savings seem substantial over the Natural Gas heat/standard air conditioning syltem that I have now, I'm still not 100% convinced because they didn't ask to see my electric/natural gas usage, they used their standard formula.

1700 sq. ft. 100+ yr. old farmhouse, no basement (crawlspace), counterflow furnace (all ductwork is in crawlspace, and is not insulated). There is a 6 yr. old 90% effeciency furnace in the house now, and I installed a fireplace insert built by QuadraFire
this Fall. I just got the utility bills last week and it said:
Natural Gas:
1-21-2009 Average temp 21.6, # of days 34, Units used 97.7
vs. last year
1-22-2008 Average temp 29.8, # of days 33, Units used 195.2
$138 for the 1-21-2009 usage
Electric:
1-21-2009 572 kwh used, average daily usage 16.8
1-22-2008 767 kwh used, average daily usage 22.6
$86 for the 1-21-2009 usage

Looking back at last years electric usage during the summer, in July I used 1114 kwh, at a cost of $167 strictly for A/C.

I installed a Bosch whole house tankless hot water heater in the Spring of 2008, which replaced the 30 yr. old Rheem 40 gallon water heater.

I was quoted between $9500 and $12,800 for an open system using a Bosch FHP. This quote did NOT include the Well and the water drainage systems, humidfier, or hot water option. From the house to the pond is approx. 200 feet, and the soil sand down to 12'. My well is new as of Spring 2007, and with the current pump it pumps 28 gpm. The well driller said that with a by changing the well pump I could pump in excess of 100 gpm.

They estimated a payback in 4 to 5 years, but I don't see it.
So, I'm wondering if switching to Geo will be worth it.

Thoughts, comments??? Any suggestions on someone esle to contact for a quote? This quote was from Geothermal Specialist, Inc. in LaPorte, IN.

Thanks!

My 2c worth:

I would start with insulating the ductwork in the crawl space. This should be done whether you change to a geo system or not. You have a huge heat loss there.

Next, look into any tax rebates on installing a geo system.

Last, I question why you would use a well and the electricity to run a well pump when you have a pond.

Don't let anyone try to sell you a "passive" water heater for your geo system. They cost 5 times as much as a standard electric water heater, which will work just as well. You can just not wire it up, or wire it for emergencies and cut the breaker off.

I agree 100% about insulating the duct work in the crawlspace. I hesitated to do that this Fall because of the water supply pipes running in there as well. (old galvanized pipe) I bought the tools and most of the supplies to change all the supply plumbing to PEX, I just have to get 2 manifolds and the PEX tubing itself.

I really noticed the difference in heating the house when I ran the blower on the furnace to suck the hot air from the living/dining room that was accumulating there from the insert to circulate it thru the rest of the house. The Master bedroom is the furthest room away from the living room, and it's 20*F cooler than the living room without running the blower on the furnace. With the fan running, the temp only climbs 4*F, but the temp in the living/dining room will drop 10 to 12*F.

The floors are cold as well, and after I switch to PEX I want to get the bottom side of the floors covered with foam insulation. If the PEX pipes do freeze, at least they won't break. I'm planning the piping so that there won't be any fittings in the crawlspace, with the exception of where the well supply line transitions to PEX from beneath the ground. (the bladder tanks are in an old underground milk room that is insulated and heated). I'll make sure that I have heat tape on the copper pipe.

I upgraded the windows in the house 3 years ago, and before last Winter I blew 18" of cellulose insulation in the ceiling. This Summer/Fall I ripped two layers of siding off of the house and covered the outside with OSB, calking all of the seams. Old Man Winter caught me before I could get the Tyvek vapor barrier up.
Every wall cavity that I checked had fiberglass insulation in it, and I couldn't get hardly any more cellulose insulation in the walls. There was the origional shiplap siding, a layer of clapboard siding over that, a layer of fiberboard/asphalt granular siding with the exposed siding being aluminum. I ripped all the siding off down to the clapboard. When I replaced the roof 2 years ago I added a temp/humidity controlled power vent.

The duct work is the older galvanized tin. What insulation works better, the bubble/foil wrap or the fiberglass/plastic faced?

It is below the frost line and the pipe was insulated. Once we get out of these terribly cold weather I would like to maybe disconnect the strips or such.

The company that did the actual sinking in the pond to house are considered the best in Indianapolis area--highly reputable. Thanks for the links, I'll be sure to go see what the thermostat one says that is different from the papers that came with it. I think all of you are giving me a wealth of information (that I'm trying to absorb). We knew when we put this geo in that it is a complex system to learn about and understand (and we are trying to). The HVAC company is reputable, our unit was an updated model. I read some notes they put on receipts and there was a note about the 'stat maybe not staging properly'. Mark did not ask him about that when he was here this past week to check why the lights were dimming (the tech was to get a hold of ClimateMaster). Huummmn? I think I will do some checking at the links you noted and makes some calls.

WOULD I RECOMMEND GEOTHERMAL? - You bet! It's nice to be warm, not worry about what the thermostat is on, and not have those $1,000 LP bills coming at me. No regrets, worth the up front costs--payback 5 years--well worth it and an investment in our home. I do appreciate all the info sharing; great site--this Pond Boss for my geo and pond information.

The foil/bubble paper R-values aren't great when contacting what it's insulating. Fiberglass is likely better if you're just plannng to wrap the ductwork. Keep in mind that the vapor barrier belongs on the HEATED side. About 90% of the DIY crawlspace insulation jobs I've seen have been installed wrong.

I think I saw an Owens Corning pamphlet one time that said you lose like 40% of your heat through the floor.

Esshup: $160 for gas doesn't sound all that bad....I guess it depends on how much wood you're going to burn and the cost of wood. If you could save $100/mo on heating and cooling...that's still only $1200/yr and would take quite a while to recoup you're costs...possibly as long as the life of the system. Burning wood in addition to using gas is kinda a wild card that is hard to put a value on.

Blaine, I got my electric bill covering the coldest temperatures here in 30 years. It was $267.34 for 24 days. Honestly, I don't think that is bad at all, about $100 more than what I had last year (before geo). We're going to wait until next week and try to turn off the strips and see if we can see any difference.

Mark, I'm trying to follow the cost savings of Geothermal here, so your electric bill went up about $100 for 24 days, and you mentioned not having a large propane bill. Any idea how much money you are saving per month or is it too early to know yet?

Myself and I suspect Brettski are following this thread.

...with interest

Thanks for the update Markecin. My huge bill may have been caused by a faulty water sensor scheduled to be fixed Monday morning. I may never know but $480 for one month was more than double the amount that I expected. I will definitely be keeping my eye on it though.

Yet another VERY interested reader. I'm in SE Iowa, building a large shop/garage this spring.

I'm trying to decide among several options...

1. Install GEO (using pond or otherwise) for the house only and tie it in the note for the shed. Heat shed with in-slab radiant using propane water heater.

2. Install GEO for house and shop...is this even possible using one unit?

3. Forego GEO altogether...not likely, as I spent $2000 on propane this past fall, and while it's down a bit now, LP will probably climb back eventually.

Pond is about 150' from the house, so it's definitely doable. Just not sure how much experience local installers have with that type system...gotta talk to 'em about it, I guess.

My house is probably not too far from your location as we are south of Indianola. We heat and AC our house and garage (about 4000 sqft) with GEO. It was installed 2004 by LesMes based in Truro. They sized the unit and specified all the components such as pumps, thermostats, tubing, fittings etc. and installed it. My observation is that those guys understand the plumbing part pretty well but have only enough knowledge about the controls to make it work. After talking to other contactors I think that they are all like that.
At the end, after about one year of operation, I made several small changes to the "plumbing part", fixed few leaks and replaced the controls altogether.
Our heating electric bill in January was about $100.

Ladia,

Please share these changes and tweaks with the group, maybe we could all learn from your findings.

What was your average monthly heating bill before the changes were made? After?

First I measured temperature exiting from all ports of the heat accumulator in both heating and cooling mode. There was significant temperature difference between top and bottom discharge pipe in cooling mode. The cooling loop was originally connected to the same pipe as heating headers getting higher than desired temperature. After relocating the Toff to the bottom port (return to the HP) performance of the AC improved significantly.
The original control system provided only temperature control in 5 zones while the HP operation was controlled by temperature in the accumulator. Therefore the HP was needlesly running for about an hour or more/day even when there was not demand for heating or cooling.
Switching between heating, cooling or standby had to be done manually. It didn't provide temperature control of hot water that often overheated and popped overheat protection in water heater. When the weather got cooler and AC stopped operating there wasn't hot water until the protection was reset.
Therefore I bought small PLC (LG because it comes with programming software), 24V transformer, 10 relays, two dual temperature controllers, 1 60A contactor, terminal blocks etc and small cabinet. All together for about $500. The PLC has 24 discrete inputs and 16 discrete outputs.
All thermostats are connected to PLC inputs, all zone pumps and zone actuators, desuperheater pump, water heater, HP start request and reversing relay are connected to PLC output. One of the two loop temperature regulators controls heating and cooling temperature, one loop in the second controls HW heater temperature (desuperheater pump). The thermostats in the HW heater are set to lower temperature than the desuperheater loop therefore the electric heat is always turned off as long as the HP keeps the water hot or anytime when the HP is running. HP starts only when there is a demand for heating or cooling. Switching between cooling and heating mode is automatic. The PLC also controls recirculator of the hot water and turns all pumps on for 1 minute/day to prevent sticking. It also keeps track of number of starts and time running in each operating mode but I didn't analyze that part yet.
Beside relocation of chilled coolant for AC I added ports for possible future heat exchanger to heat HW solely by the HP and use electric heat just in the case HP fails.
Added ports and valves in the HW (desuperheater) loop used for descaling of the desuperheater heat exchanger. Added air trap consisting of 3 feet of vertical pipe Teed to suction of the outside loop pumps. The pipe has a valve in the top to let the trapped air out. It was needed only first few months of operation.

I also installed thermometers on every manifold and pressure gauges to outside and inside loops.

I would make just a guess that the total house electric bill decreased by 20 to 25 USD/motnh (about 10%). 10 USD comes from the heating and 15 USD from HW.

Wow. My brain hurts. What is a PLC?

Programmable Logic Controller. Think computerized super version of the old 24-hour on-off 110vac switch grandma used to fake being home while she was on vacation.

There is not a simple solution to complex problem. Geothermal heating is complex thus the control system is also, not necessary complicated, but complex. Leaking pond is not complex but the solution is complicated. Ask me about that one.

I don't know what I'm missing, but on my geo system I turn the thermostat up if I'm cold and down if I'm warm. Not really too complex.

Sounds like what I used to say Jersey... Until I got that first $700 heating bill. I have found that it pays to know the intricate workings of the system.

It is like modern cars. You start the engine and drive. That is not complex. Look under the hood. That is complex.

I believe that to get peak efficiency from a geo system, it must be understood, monitored, adjusted on an as needed basis. Many changing factors continually determine the adjustment frequency. Any of you who have paid an electric bill where the emergency heat strips were on more than they should have been will agree.

Since the heat pump can do more than heat/cool your house the control system should allow you to take advantage of it. Example:
The heat pump can heat HW four times cheaper than direct electric heat and heat it for free when AC is running. Therefore the control system should be smart enough to turn the direct heat ON only when the HP is not available due to failure, being turned off etc.
The main challenge is to match the HP and the controls to particular house. Ideally the HP should run continuously at extreme condition while still maintaining sufficient temperature inside the house. That is the American way designing it.
In the Europe they design it for about 70-80% load and then cover the deficit by direct heat. The thinking is that the peak load is required less than 10% of heating/cooling time while the HP, ground loop and total cost of installation is significantly less. Additionally the smaller HP cycles less.

When the system is new it should be mandatory to check not only if it meets expectation but if there is room for improvement in efficiency and/or comfort.
Example: Typical setting for floor heating temperature is 110 F. But I found that it works as well at 90F. While ago the HP run almost continuously for few days during very low temperatures and high wind. It was able to maintain only about 90F of liquid entering the floor because almost all loops were ON. But the temperature in the house was still maintained at the desired SP. Therefore I set the HP set point to 90F. Since efficiency of the HP is proportional to inverse of the temperature differential I expect that the lower temperaure rise will save some energy.

Wow Ladia...you are really up on this subject like a pro's pro!
-
...you better not turn out to be another one of Dwight's cats

Well my pond is leaking and the HP heat exchanger is in it. Will exchange geo advice for pond advice. I NEEEED POND HEEEELP.

Looks to be about $2,800+/- a year vs propane (so my 5 year payback should be close to target). This year has been cold, moreso last month, payback could be sooner as I'm sure I would have had larger LP bills than previous years. It will be intersting to do an overall analysis once I get the 5 years behind me.

Wow, if mine would have been that much more I would have been regretting putting geo in but of course we both know that meant something was wrong. It will be interesting to see once your sensor is repaired what you average down the road. d

Thank you, that was exactly the type of information that I was looking for. I'm following this thread closely, this is a facinating subject.

Propane, NG, heating oil etc are subject of swing in the price due to demand, speculation etc. Because the electricity generation and distribution is highly regulated (and is generated mostly from coal) it doesn't suffer unpredictable price swings.
Considering the cost of hydrocarbon fuels in the past several years my geo already paid for the difference in installation cost geo versus propane furnace. My cost was significantly higher due to installation of floor heating and air-conditioning.
We paid in average (and that is very rough estimate) about $70/ month for heating between December and January. Since the utility charges .041/kWh for the heating we have used about 1700 kWh/month. That is equivalent of about 58 therms, or about 41 gal/propane or about 5.8 million BTU. Heating the house by direct heat it would require about four times as much energy. We heat about 3700 sqft and the system was installed in fall of 2004.
I don’t do such calculations for living so, please, check the numbers before you take them as face value.

Now I don't have practical experience with a ground source heat pump, so with that disclaimer out of the way....
These systems should be less complex than a comparable air source system.
The driving force with these systems is using the heat stored in the ground vs air so there is less variation to deal with.
Right off the bat that means you don't need the energy robbing defrost cycle when the air temps are low. You are running an antifreeze solution through a closed circuit so you don't have to worry about the neighbor's cottonwood tree clogging up the outside heat exchanger.

The big variable with ground source is that the engineering and installation of the loop is critical as that is not pre-sized and tested by the manufacturer. However the tools and test equipment to evaluate the loop are common and inexpensive.

In a ducted system they are both equal in their complexity and unfortunately designers and installers have a pretty poor track record in executing this part of the system. The most efficient, magical box of engineering in the world can't overcome shoddy or poorly designed duct work. Again the tools for evaulating this part of the system "should" be standard kit with with a qualified contractor.

The accepted standard for sizing both air and ground source systems is called "Manual J". It works, but requires carefull and accurate input. Garbage in garbage will win in the end everytime.
Down here, in Texas, systems are usually sized for AC load. An oversized system can be worse than undersized as failure to control humidity has led to more than a few houses being dozed due to mold infestation. Variable speed and dual stage heat pumps can be a good way to deal with the extremes.

In the end there are fairly simple and objective methods to measure the systems perfomance and there should be a set of inputs the contractor used to size the system. It's a simple matter of comparing A to B.

The subjective areas are the inputs to the "Manual J". A certain margin of error is endimic here as the HVAC Co. can't be responsible for the building envelope.

I have tracked all my utility usage for the past years meticuously and know how much it changed year to year, what my averages were, etc. etc. Ladia is so correct about the swing and demand factors. Over 10 years I've watched swings in my own usage and utility prices. I have watched my LP prices go up over the years $1.10 in 2003 to $2.48 in 2007; thus, you can understand my decision to forego geo once we put the pond in; it wasn't if--it was when. I watched electric go from .0897 per kwa to .10/.11 2008. I would suggest anyone thinking of going geo to do their math based on their own situations.

The geo system can be simple or complex. Generally the forced air is about as complex as furnace.

Floor heating is another story altogether. Since there are many floor loops it is easy, if structured properly, to zone each room with own temperature control. The HP also heats HW so that loop also has to have a temperature control loop and has logic that disables direct heat when heat from HP is available. The heat/cool accumulator also has to have own temperature control. Then there is AC with its own temperature control and there is logic switching between heating/cooling. Because of large time constant of the floor heating (0.5 deg/hour) the mode of operation can't be changed forth and back like in forced air. My system uses high pressure AC that works very well but it makes whole house filter integration difficult. So there is logic in the system associated with that etc.



If you put the loop in the pond the biggest expense it the underground line from the house to the pond. So if in doubt add more coils in the water. It will increase the cost only marginally. Ground loop is another story. Over killing it will not improve or hurt the function but hurt you pocket.

My point which, I probably made poorly, is that the closed loop, ground source system setup properly should require less adjustment and maintenence that a comparable air source system.

Clearly any system can benifit from enhanced control and monitoring. No telling how many megawatts are wasted in this country because of dirty air filters or clogged evaporators on forced air systems. Variable speed blowers provide a means for a dehumidification cycle but few systems are being installed with the humidistat required to utilise this feature.

I could go on but the point being that there is nothing specific to the geothermal cycle that requires the consumer to be conversive in ladder logic to enjoy the benifits of these type systems. They are little different in their maintenence demands than the refrigerator purring away in the kitchen.

Multi-zoned, multi-staged or mixed systems are by their nature more complex be it geothermal, air source or a boiler system. The system designer and installing contractor are the keys.

I have to respectfully disagree about the complexity of the geo system. As a forcd-air system, it is really no different than a typical heat pump. It just exchanges heat in water instead of air, a much more efficient process.

One benefit of a geo system, as mentioned before, is it uses its waste heat to heat water. I do this process in a standard 80 gallon electric water heater, with the breaker turned off. This tank feeds another 80 gallon tank that takes over if needed, but at least it always receives water significantly warmer than it would directly from the well.

Now if you have radiant heat in your floor, especially in a concrete slab, you do need some fancier controls because of the thermal mass. This is a whole different topic.

Assuming geo with floor heating and AC.
Since each room has at least one but usually several floor loops it is easy to control temperature in every room (zone) separatelly. As opposed to natural gas, oil or propane furnace the heat pump can heat HW cheaper than direct heat. In fact it will heat HW for free by waste heat when AC is running. All this require temperature control for each loop.
So typical three bedroom house will have:
1.) Eight zones (kitchen, living room, bedrooms 1,2 and 3, garage, bathroom 1 and 2.
2.) AC temperature control (one for whole house or also zoned).
The zone thermostats for floor heating use different temperature algorithm than thermostats for forced air. The issue is a lag time between introducing the heat in the room and the temperature response. For forced air it is measured in minutes. For floor heating it is measured in hours. The thermostats are actually simpler because they are not programmable.
3.) HW temperature control with a logic that would enable direct heat when heat pump is not available.
4.) Heating/cooling accumulator with two heat and cool temperature control loops. The control loops control the temperature in the same vessel but have their respective sensors on different outlets.
5.) Logic switching between heating/cooling mode.
6.) Recirculation pump "excersise" function to spin all pumps for short time every day to prevent stiction. That is especially important for variable speed pumps set to low speed because they might not start after one season of inactivity.
I see the difference in the fact that for furnace forced air all the controls are more or less standard and built in the system. Just add a thermostat and you are ready to go. Geothermal with floor heating is designed according to specifics of particular house. I believe that purposely made programmable system for such application are already on the market making application of the geo and its efficient use easier.
When I built my house I was quite naive and thought that the guys installing it will install all the necessary equipment and proper controls. Only later on I learned that it wasn't necessarily the case. They made it work reasonably well and it was about it. So I built my own system. It was fun project but after the experience I would buy off the shelf controller and use it. Therefore I would strongly advise to avoid custom made systems based on a PLC and similar for most homeowners. The issue is maintenance and repair when something goes wrong. Most homeowners will be better off with off the shelf product that can be troubleshot by average HWAC tech. I built my own control system so I can fix but I doubt that average heat pump or HWAC tech could come to my house and deal with possible problems. Heck I have problems to fix program bugs etc sometimes.

Integrated of the shelf control systems are available from
http://www.tekmarcontrols.com/literature/a.html

Wow, Ladia. I missed your responses (several, along with others) over the past several days.

Now, I'm wondering if this is even something that I should attempt here (small town) with local vendors. When I first thought about this in '01, the ONLY outfit doing it within 35 miles didn't instill lots of confidence. The sold the HP and would install it...but (pre-pond) argued amongst themselves for a couple weeks as to how much tubing (digging & $$$) would even be required. I walked away...

I'm only 40 mins from Iowa City, so maybe there are others there I can talk to about this.

My shop will not be attached, but sit perhaps 50 feet from the house. It will have in slab radiant, I've installed it before, and will this time. Home has LP fired forced air...not sure how these 2 systems will (or even could) be tied together. Shop radiant can easily be supplied by 60 gal HWH, AC, perhaps just a window unit - I won't live in the thing!

...probably simpler to keep the systems separated.

This is one reason I wanted to let you know that it is not complicated, unless you want it to be. Radiant floor heat is it's own system, whether it is heated by geo or otherwise. Using geo for forced air heat / AC is not any more difficult than a conventional system. Let the geo system heat the tank of water and let the radiant system do it's own thing. Personally, I let the geo system heat my domestic hot water, and keep the radiant floor system seperate.

I have been told 500' of pond loop is required per ton, and that is what I have. It might be different in other areas.

I bet a geo manufacturer could answer your questions and recommend a good dealer in your area.

I would hate to see the description of Ladia's gee-whiz system discourage anyone.

Geothermal is supposedly very popular now. Especially for new construction. The guy who sold the system to me told me (he installs the ground loops) that he was booked up for several years in advance. Now they have new drill that can pull the tubes underground without major digging. I also think that the installers got much more skilled, since I installed my system, (well there is a software) in calculating all the required specs. If you don't need AC (you can always add it later) the floor heating with geo is not much more expensive than forced air especially if you can lay the tubes by yourself.
By the way most of the utilities also sell the geo system.
Obviously the best and cheapest heating is insulation. Combined with HP it might also be the least costly to operate. If you use geo for heating only it is about as complicated as forced air.
The two system could coexist several ways. I would use two separate heat accumulators each with its own temperature control and circulation pump. One could be set to floor heating temp 90 - 110 F and the other to forced air temperature 160 F with house heating demand priority. Then you would have to replace the furnace with an air handler or add the air handler in series with the furnace so you will have a back up heating.

I agree. I think the controllers that would do the job without exotic solutions are on the market. Since the geo is more or less mainstream now the installers are better trained and more adept to do it right.
Geo is hard to beat in cost of operation even if the utility starts charging the retail rate (most utilities charge the wholesale rate now).

Ladia,
You mean you have one meter for HVAC and another for the rest of the house?

When you said above "using geo for heating only" you lost me. My system is a forced-air heating and cooling system, just like most conventional heat pumps. This is it's only function, the domestic hot water is just icing on the cake.

I know they make geo units that only do one thing...heat water. Some people use them to heat swimming pools and radiant floor systems. Is this what you were referring to?

Is your radiant floor in concrete or under a wood floor?

Yes we have two meters. The utility charges the wholesale rate just in the heating season.

There are three basic Heat pump arrangements: Heating only, cooling only and reversible heating/cooling. To achieve maximum efficiency it is important to use the heat pump optimized for your particular climate and type of the heating system such as floor, hydronic (with radiators) or forced air.

We have floor heating with PEX embedded in concrete slab. Since the efficiency of the heat pump is inversely dependent on the temperature differential the floor heating is probably the most efficient because it has the smallest temperature differential.

Needless to stress the obvious: The best heating is insulation, insulation and insulation.

Anyone here take advantage of the $2000 tax credit for geo installed after Dec 07 ?

Ladia,
That explains why your system is more complicated than mine. Again, mine is strictly forced air heat & cool, with the super deheater heating the hot water. I have pex tubing in the entire basement floor, in 6" of suspended concrete in the kitchen, and 3" suspended concrete in the master bath, but none of it is hooked up yet. I have not figured an easy way to use the geo system to warm these floors, since I am pretty much using all of the hot water the system produces for domestic. In fact, my electric bill stayed the same last fall when we quit using the A/C. The electric water heater had to take over. I might as well keep running the A/C.

I am thinking of just using a small water heater and pump to circulate 90 - 100 degree water through these floors. It won't be so much to heat the house, just enough to take the chill off the tile floors.

As you mentioned earlier, with radiant heat, especially in concrete, you can't just decide to raise the temperature because you are chilly. It takes several hours to make an adjustment, both up and down. Does your system look at the temperature and trend outside to decide that it's time to start (or stop) warming the floors? I don't know if I will need this or not, but it is something I would like to learn more about.

Seems to me that I got myself deep in the discussion about geothermal heating cooling so I should make one thing clear. I am not an expert on geothermal heating but I learned a lot while implementing geo in my own house. My intention is to share my own experience with my own geo system to help other people to avoid mistakes I made and/or help them to be better informed about the issues associated with the geothermal systems. My background is in control systems. I install and set up control systems for industrial processes (such as oil refineries and chemical plants) for living. Therefore I decided to design and make my own control box because of the shelf product was not available at that time. It was also fun project but if you ask me if I would do it again the answer is NO. I would do it again only if there isn’t an alternative.

My system is complex (not necessarily complicated) due to the fact that I have several zones each with individual temperature control. I have integrated whole house filter with the AC. The filter uses the same ducts but otherwise it is separate unit with its own fan and heat recovery etc.
Both the heat accumulator as well as HW heater have individual temperature control. I might add AC with all associated temperature and occupancy control for the garage/shop later on.
Switching from heating to AC is automatic. We have one "smart" thermostat (located in the kitchen) that has built in an algorithm to select heating and cooling mode but I found that it could get “fooled” in example by baking Christmas cookies that generates a lot of heat or when we used a fireplace etc. Therefore I added a logic that checks if the demand for heating or cooling is sustained and then switch. The heat accumulator is "charged" (kept hot or cold) only if there is a demand for heating or cooling. The original control system kept the accumulator charged even when there wasn't demand for heating or cooling for several weeks at spring or fall. All pumps are cycled every day for one minute to prevent sticking due to long inactivity etc. The control box also controls the cycle for HW recirculator so there virtually instant hot water from the faucets but the recirculator doesn’t need to run continuously.
The temperature in the heat accumulator is fixed so the system doesn't look at ambient temperature but I might add the sensor just for information.

I wouldn’t use direct heat for floor unless you can’t justify the cost of adding the floor heating to the HP. The HP will heat the floor four times cheaper at retail electricity cost and about 8 times cheaper at wholesale cost. The cost and complication will depend on your system. I don’t know if your system has separate fan coil or if it is all in single unit similar to furnace. It might or might not have heat accumulator and/or even provision for floor heating hookup (in ex: built in heat exchanger and circulation pump). One thing you need to know about floor heating is that the floor is cold to touch. It feels warm only if you have socks or shoes.

Ladia,
Mine is a self-contained unit (Waterfurnace)
It has a circulator pump built-in for the super-deheater, which can be switched off it you don't use it. (Why would anyone not use it?) It could be used for radiant floor heat, but I really think I use most all of the hot water it can make. At least in the winter. In the summer, I have both the passive and active 80 gallon tanks full of free hot water. But no need to heat the floors in summer.

Interesting conversation and observations.

MarkECIN, I don't know if you're still having trouble with your electric heating strips coming on too often, but if you are you might check that your water lines to the geothermal unit aren't freezing. Our unit is in an uninsulated attic area and we had some really cold days right after getting it installed. When the lines froze, the geothermal heat stopped working, when they thawed, it started working again. This can make it difficult to diagnose! If this is the cause the solution is wrapping the pipes or possibly building an insulated closet around your unit.

We're using a Climatemaster and we had our HVAC guy set us up so that the heat strips never come on automatically. Our thermostats (honeywell touch screens) still shift between indicating "heat" and "aux heat" as if they're using the auxiliary heat strips when needed, but it's really always using only the geothermal. If we ever decide we need the electric heat for some reason we can manually switch to "emergency heat" on our thermostat. I think this is a much better set up since if the geothermal isn't working or keeping up for some reason I'd rather find out by getting too cold than by a huge electric bill a month later. Of course, this might not be a good idea if you're leaving a house unattended during cold weather, but for us it works great.

Jersey,
Any conventional AC or Heat Pump unit can have a desuperheter installed for heating water. It's not restricted to geothermal. However, with geothermal units it's typically much more convienient as many have the desup built in or as an easily installed option.
In cooling mode the desuperheater acts as additional condensing capacity utillising some of the heat wich would be rejected (to the air or pond loop for example) to heat water. There is no reduction in system capacity.
With a heat pump in heating mode the opposite is true. There is a reduction in system capacity (10-15%) if the desuperheater is used.
So this is definatly one area where seasonal adjustments or an extended control set might make sense. For example, one wouldn't want to be paying to run the heat stips on high demand nights because 10% of their system capacity is diverted to heating water while they sleep.

Hot water demand tends to be transient and there is typically very little relation to demand and outside temperature. It's certainly important that the controls for HW heat be setup properly. Ladia and I had a discussion offline about this. Thier system was initially installed with no temperature control for the desuperheater. The desuperheater ran all the time the system was on regardless of the HW temperature. Other than being inefficient, there is a danger of scalding in a situation like that.

This is certainly one area I would quiz the installers about if I had one of these systems. It's important to know the temperature settings on the hot water heater and desuperheater settings and make sure they are set properly. It's information that you need to know anyway so when the HW heater is replaced it can be setup properly. The desup settings should be less than or equal to the HW settings. Some systems have additional controls for the desup circuit and can turn it off based on staging for example. I'd ask if this is being utilised and how its setup. It may be an option you have paid for and the installer never bothered to turn it on.

I agree with most statements of tejasrojas with one exception. If the building has large thermal mass such as floor heating embedded in concrete floor I would set the desuperheater temperature higher than the hot water heater thermostats to give it a preference. Loss of the heating capacity caused by heating hot water is usually only temporary (It will not cause noticeable discomfort) while it is significantly cheaper way to heat the hot water.

The logic that turns the heat strip on in forced air system should have reasonable time delay so the direct heat will turn on only when it is certain that the heat pump can't supply sufficient heat. It shouldn't turn on instantly when the temperature drops too low below the set point. In example when door is or window is opened for short time. I personally would disable the heat strips and re-enable them only in emergency. The short loss of comfort is not worth the money it costs.

I just learned the hard way why not use custom-built control systems.
I am currently on a business assignment overseas and will not make it home for at least one more month. My wife reported there isn't hot water in the house. The logic in my PLC disables hot water heater anytime the geo is running and re-enables it when it stops. That way the geo keeps the water heater charged preferably by the heat pump. The problem started when PLC requested start of the heat pump but it didn't start for at this point unknown reason and thus kept the water heater disabled. Then I spent few hours of figuring out how to override the PLC and instructing my wife how to reprogram the HP to stand alone mode, latch primary pump relay to always on, set heat accumulator SP in PLC cabinet to low temp so the logic would think that it is hot and didn’t try to start the heat pump thus disabling the hot water heater etc.
So now the house is warm and hot water is available.
Lesson learned:
The emergency PLC bypass should be built in the system, tested and detailed override procedures written. In other words I have to redesign the whole thing. It will be fun project. Well, until something unexpected happens again.

Actually did get the problem resolved. Electric transformer wasn't big enough to keep everything going, electric company replaced.

I'm reading everything y'all are writing as I have to learn now that we have this geothermal pond loop. But I cannot say it enough-- I don't miss those high LP bills we used to get!

Ladia, I just have to say this--you are a "wealth of information" and if gained by experience, I hope to someday be as smart as you about this geo stuff to where I can trouble shoot some problems myself too. Thanks for your input. I'm catching up on my reading on the forum. d

I have reading this forum with interest and it is VERY informative! I like to read about people who have 'been there, done that' before deciding on something. We live in south Alabama where the main concern is hot, humid summers. We are building about a 3 acre pond and a 'retirement' cabin (more like a house...2500 sq ft)using mostly all reclaimed wood and beams from old houses(will be timber frame.) We are very interested in geo thremal for the pond. It almost doesn't make sense not to go geo!I have read through these post and have a few questions. When you mention the power bill being MORE, is that just for running the system? I guess since we don't use propane gas at all,(we have an all electric heat pump) our power bill should be LESS, right? Right now our power bill runs around 250.00-300.00 a month, whole house. About what kind of savings should we expect from the geo? Also, looked at the Slim Jims. Has anyone used these and how does the price compare to the coils? ONE more question....does anyone that lives in the south feel like the air inside in the summer is comforable, in other words, not humid? I think I read somewhere this system is also a dehumidifier. We are also looking into siting the cabin to take advantage of passive heating/cooling. The south side will have quit alot of glass and am worried about overheating. Thanks for all your help! This is an awesome forum!

Southernbelle, welcome to Pond Boss. We're glad you found us.

Thanks JHAP! You'll probably see me around here alot. Going to need some advice on the pond too! Hoping to start in a few weeks. It's stream feed, so don't think it will be in danger of going dry with the geothermal. Also going to install a dry hydrant. Any forums here on that?? The cabin will be a good way from the road and the hydrant will also be a plus for insurance. Sounds like this is going to be a working pond!It will heat/cool, supply hot water, put out a fire, provide fish and hours of enjoyment. Anything I'm missing?

SB, I'd advise you to start a separate thread. I believe that several folks here have dry hydrants but I'm not positive.

You came to the right place for advice, some of might even be correct advice.

I found the dry hydrant thread-sorry!! Didn't think to do a search-duh!

Southernbelle, on our geo system we have the fan that runs constant for filtering the air (they just recommended to run it that way and we have been, you don't have to)so it costs a little more to run it that way. We do have a dehumdifier that we had on our previous system that we had the installer hook up to our geo system. Works fine that way. (PS...I'm originally from Louisiana so I know all about those hot humid summers).

Ladia, what's your take on running the fans constant? I'm still learning here. d

Southernbelle,
Check out
http://www.tractorbynet.com/forums/
IIRC there were several dry hydrant threads there.

Matt

thanks Matt--who would have thought to look there. You guys know all the secrets!

Hi Sbelle...welcome.
Your project sounds like a wonderful undertaking. Please, be so kind as to allow us to tag along as it progresses. Start a thread for your pond...and...please start a thread for your home construction. Get a photo hosting acct established and bring us pics and descriptions. We love it. The inspiration that you provide is the fee we charge to play.
-
Is this the dry hydrant thread that you found?

Fair enough, but this scenerio is correct only if the aux heat is disabled. Otherwise, when outdoor temps fall to 85-100% design temps, aux heat is going to kick in to maintain the hydronic loop. It's really more of a question of capacity and how often the system demand is near or at full capacity.

I mention this because, as you know, some of the desuperheater controls are quite primitive. The default mode for one paticular unit consists of nothing more than a high limit set at 140F attached to the desup inlet line. The desup runs anytime the return water is under 140F even if aux heat is on. Adjustment consists of moveing the high limit to the desup output to lower the temerature. One has to pull the fuse to disable it.

Other systems have adjustable desup controls that one can match to the WH control and have additional control logic to shut down desup when aux heat is called for.

Some systems extend this control set with multiple stages so desup can be shut down before aux heat to allow the system time to meet the demand while running at full heat pump capacity. If the system still cannot meet demand additional stages of aux heat are turned on.

The better control for hydronic systems monitor outdoor temperature and use this information as part of the control loop. I think this is clearly the best way as the floor loop temp can then be matched to demand. The desup can be shut down as system reaches max capacity.


I have never disabled ours as I have to travel too much to see it as worth the risk. Because ours is an air source heat pump, we make an attempt to provide suplementle heat (wood stove fireplace insert) whenever the outside temps fall below ~35F for an extendend period. This is not because of aux heat, but we try to minimise system usage when defrost cycles are required.

So glad you brought this up.
During my minimal research into geo HVAC, I wanted to know if there was even a prayer for it's use with an off-grid solar power system. I contacted a geo contractor to discuss power draws. Besides the normal amperage, he noted that the defrosters would be killers. Huh? Defrosters? As I understood his explanation, just like a window air conditioner that runs too cold for too long, the coils can eventually freeze up with frost on their exterior. OK, I know that occurrence. He said that a HP is exactly the same, operating in reverse. The same thing will occur and some killer amperage defrosters can/will kick in for about 5 minutes to melt it off.
Correct?

Sounds like he was describing an air source system. Geo does not require defrost. Antifreeze is circulated in the ground loop and the system simply shuts down if it gets too cold. It souldn't shut down if the loop is sized properly and the flow across the heat exchanger is correct.

You might want to consider using a Solar collector to heat water to supliment this system.

Oh, goody, so I can play?? LOL I'll do that, and start a thread soon as we get started on the pond. We are lucky in that my husband works for a roadway contractor(project engineer) so they are going to come with all the equipment and do some digging. (trackhoe?)Since they are doing this instead of us having it hired, we can make it larger than originally intended. We both love to fish and I can't wait to see this pond take shape! Been in the planning stage for years and years. We cut the timber last fall and now we have the funds to proceed. We are going to build a nice pier, and even a pavillion on the other side for tables, etc. I have friends that did this and decided I HAD to have one too! They have a little kitchen and bathroom (with used appliances). I even thought maybe to include a set of bunkbeds for hunters and fishers. Of course,plenty of hammocks outside, grills, fish cleaning station, fish fryer....oh, I can just see it now :~)Ya'll come!

Our heat pump runs nonstop only at very low ambient temperatures and windy nights. I am guessing only for few days in each heating season. Also our house cools down very slowly it takes about 8 hours without heating to feel noticeable discomfort even at very low ambient temperatures. So in our installation we hardly notice loss of heating due to heating of hot water.

We have installed 9 kW electric heaters in the heat accumulator but the breaker was never turned ON. We might use it only in emergency when the heat pump fails completely or we might never use it because we also have two propane fireplaces located strategically in the house.

We know people who have floating bedroom on their pond. How romantic and original. We are going to build one too but only after we find and fix the leak in our pond.

It all depends on how much money you want pay for increased comfort. If money isn't object I would add whole house filter integrated to the AC ducting. The difference between recirculation and separate filter is that the filter draws certain percentage of air from outside trough a heat exchanger (to increase the economy) and keeps the house under small positive pressure to prevent dust from outside entering the house. It also have hypoallergenic filter that is not always easy to incorporate in the AC. The reason is relatively large pressure drop at the flow rates used to cool or heat the house. The filter flow rates are much smaller.

Fan coils for geo are usually two speed. High speed is used for AC and the low speed is used for circulation.

The efficiency of heat pump in general depends on the temperature differential between outside and inside of the house. The smaller is the differential the better is the efficiency and vice versa. In other words the greater are the temperature extremes and longer is their duration the more advantages is geothermal system. So in some climate such as NC, SC, VA or OR air heat pump would work quite efficiently but further south or north geo is the winner.

Here is a sneak peek of the cabin -to- be by the pond-to-be..

http://ourdreamgreenhouse.blogspot.com/

oh, do tell all! A floating bedroom....never heard of that. Good place to put the hubby when he snores. I'll even tuck a fishing pole under the sheets so he doesn't wake up complaining.

Well, I have to correct my statement. I thought that those people were my wife's clients but I just talked to her while ago and she said that I am confusing it with a show in TV she told me about many years back. In any case I think it is great idea regardless of the source. We definitely plan to build one and use it.

I love your project. But it is a lot of work. More than building from scratch.
We have the shell of our barn built by a contractor and finished it all inside by ourselves so we can apperciate it.

Well, we have a picture frame business, using only old distressed wood siding, so once we tear off the siding, we just keep going. We just get what we can use...alot of the inside tongue and groove we can use too. The rest we knock off walls with chain saws. The hard part is getting the nails out. UGH! Those old square head nails are so soft. Since we are after the beams underneath mostly, that's the prize once we get through. It is hard work, but usually free wood. Wood that can't be bought. I priced an old beam the other day, 1000.00 per beam! So I guess if we get really bad off, we can sell all the beams. How are you going to build that floating bedroom?? Like a raft?? I could see taking an afternoon nap while hubby fishes for dinner.

southernbelle,
Alot of questions here I will try to cover what I can.
I would start by trying to optimise the building envelope. There are software programs availible that you can model your building in and they will output the thermal performance. They use historical weather data to calculate the heating and cooling demand. It will calculate solar gain. Once you have the model you can optimise it by changing glass type, adding overhang, reorienting the direction, adding insulation, ect... You can see the effect of changes imeadiatly and decide what's cost effective. The one I used is called HVAC-Calc and it's ~50.00 for home-owners. HVAC-calc

The Slim Jims you refered to appear to be pretty good units. These things are installed all over place in Asia and Europe. They're duct less units so they are pretty cost effective fo retrofits. Their top of the line units use a variable speed compressor so you can try to match the output to the load. Your floorplan and lifstyle will dictate how effective a zoned system can be.
Generally speaking the geo system should cost you about .60 to the dollar, btu for btu of what a good air source HP system would cost. It depends on how mild the climate is. Up north the difference is greater and if you're on the coast it may be less. You really have to do the calculations for your specific area.


There are two types of cooling loads, sensible and latent. Sensible is dry bulb. Latent is wet bulb. The higher the humidity the higher the latent load will be. In a forced air AC system humidity is removed by passing the air across a cold heat exchanger. The water condenses on the cold surface of the heat exchanger and falls into a catch pan via gravity. It's very important that the AC system is sized correctly to deal with both type of loads.
If the system is too large it will cool the space without removing the latent load.

I don't have specific plan at this time just the idea. Our pond is leaking about 1"/day when half full. The watershed is somewhat marginal for our area so our priority is to increase the watershed by digging a draing diches cross horizontal line in the walley downstream of the pond. And obviously we have to fix the leak first.
For the floats I was considering plastic 50 gallons drums (sometimes for sale $10 each) or the floats they make boating docks from. I am thinking about 10X10 to 12X12 size.

what will be on it? Just a mattress? Hope you get your pond fixed!

Southernbelle,
My house is mostly glass facing south, and I have seen no problem with this design. There is a minimum of roof overhang, but the sun being low in the sky in winter and high in the summer is what makes all the difference.

tejasrojas is referring (I think) to a wall-pak A/C, not the Slim Jim you mean. That is, I think yu mean the radiator thing that goes in the pond rather than a few thousand feet of plastic tubing. I found that a Slim Jim casts about as much as having the tubing installed. It has to be kept clean or it doesn't work, and I just couldn't justify not going the conventional route. It might be worth doing in a small pond, but you say you will have 3 acres.

I'm heating / cooling over 7000 sq ft with a 6 ton geo system. Humidity is not a problem here in Georgia. Neither are the electric bills which are under $100/mo.

Brettski, a geo installer told you about the defrost cycle? Find a new geo installer.

Blaine, I got my shocker today, my second electric bill has come in (this is after not being able to determine if electric strips were on and also finding out that the transformer outside wasn't big enough). My previous bill was $267.00. Maybe someone can point me in the right direction. This one is or 01/23/08-02/20/08 (28 days) and says I used 5,045 KWH and my bill is $505.78. This makes me think the heat strips were kicking in full force and heating the house and geo wasn't. The geo tech never came back with an answer from the manufacturer(and yes, he's getting a call tomorrow). If the heat strips have to maintain where the geo fails, I'm in deep trouble with geo. I just need some direction in what can cause this problem, if any of you have experienced this.

Does anyone know what the termperature of the incoming fluid should be coming in from the pond as we know the tech commented on how cold it was. And the second time, he talked about how cold it was again.

What are your thoughts on this one, did any of you experience any problems in the first year of your geo (especially with the heat strips? At this rate my geo is costing $100 extra electric a month and not the $40.

thanks for the good info. I'll certainly look into that calulator software. Sounds interesting.
Are you referring to the Slim Jim Lake plate that goes into the pond? http://www.awebgeo.com/ Didn't know there was another type Slim Jim...... 'cept for maybe the beef jerky

Jersey, where in Ga do you live? I'm originally from South Atlanta/East Point. You mean to tell me there's no humidity where you live in Ga? You must be in the mts. Or that you don't have a problem using the geothermal in high humidity? We will probably have a 2 ft overhang over the glass. Glad to hear somebody local say '100.00 power bill'!! That's my game plan. I have a dumb question ...when the geo people come and install everything, does that include the unit that goes inside too? I assume you have to have all the ductwork already installed. What exactly do you have to provide and what do they provide?

Oh no.....will the Geo company reimburse you? I've read several of you mention a refund if the unit doesn't work correctly. Am I right? I sure hope it's just a glitch Mark. Let us know what they say.

I would turn the heat strips off to test if it really affects the comfort level and electric bill. If you can't tell the difference in comfort leave them off. I would also look closely at the program in the controller. In my opinion there should be a delay in the algorithm turning the heat strips on. In example the temperature would have to be below the set point for more than xx minutes or dropping despite HP running or something similar. To turn the heat strips on anytime somebody opens the door makes no sense.
I would also check the temperature of coolant entering the house. Spray some black matt paint on the suction pipe and shoot it with the infrared thermometer when HP starts and then again after it runs for certain time. The first measurement is the temperature in the pond. The difference between measurements is the temperature differential. Hopefully somebody who does geo for living will read this and tell you what is the reasonable temperature differential for properly functioning pond loop. I measured 34F several years back while estimated temperature of the water in the pond was about 36 F.
I looked at the pictures of your coils you published many pages back. The coils are so called "fluffed coils" meaning that there should be spacers between each layer of the piping and the piping shouldn't be tightly wound. Your coils don't look too fluffed to me. If the fluid is way too cold they should refloat the coils and fluff them properly. There still might be air in them. I learned from my installer that the flow center migh not be able to purge it. They used quite large portable pump to get the air out. But my house is about 50 ft above pond level.

Infrared thermometer is available here:
http://www.omega.com/ppt/pptsc.asp?ref=OSXL450&Nav=temj04

http://www.omega.com/Temperature/pdf/OSXL450.pdf

Amazon also sells them.

Ladia, Will do some checking tomorrow. Pretty frustating, things were going pretty good--so I thought--had the transformer changed, last electric bill didn't look too bad so thought maybe we 'thought' the strips were on but obviously they WERE on. We're trying to look at the book now and figure how to turn the strips off. Thanks for all your sound advice.

The strips should have its own breaker.

Ladia, my hubby just turned off the heat strips (they were on a separate breaker). We shall see.

MarkECIN, Some weeks ago I thought you might have a setting problem but as I read back through the thread I noticed on 1/17 you posted "This last week it's bee minuses and low one digit and even though we have the thermostat at 72; it shows 63 and we do believe the heat strips are kicking in a lot".
I think you need to get your contractor out and go over their calculations. Does the system perfom as per design intent and if not, why not. For example, the entering water temp had to be known in order to size the unit. Does it meet the design specifications, if not, why not? Ladia made some good points about the loop and they may be spot on, but I think you really need to have your contractor take ownership of this issue. They shoud know at approxamatly what outside air temp the heat strips kick in if they did an appropriate load calc. If the numbers don't match there is a reason.

Southernbelle,
My geo installer, who is now out of business, hired a subcontractor to install the pond loops. My system was installed in new construction, so the ductwork, pond loop, and system were all part of a package deal. All I provided was the bucket of money.

I was saying that the system takes care of the humidity, not that there isn't any.

I would definitely check the performance of the pond loop. Here are few more hints:
If the inlet temperature is low after the HP runs for a while the loop performance is poor either due to too dense winding of the pipe or air trapped inside. If the inlet temperature is OK but return from the HP is low the flow is not adequate. It might be caused by pump cavitations due to low pressure in the pond loop, one pump in dual pump system not working or some restriction in pond loop. There is a pump curve and expected pressure rise (head) in the HP installation manual. If suction and discharge pressure are measured the chart could be used to read the flow rate etc. Low head means high flow rate and vice versa. Listen to the pond loop pump while it is running. It should emit monotonous hardly audible sound. If the sound is "whooshing" or varies in intensity the pump cavitates or there are air bubbles passing trough. If I recall anything else I will post it.


If you have digital steak thermometer use it to check on on the temperatures. It is imperfect but it will give you at least some idea if you need to invest in or borrow the infrared one. The heating season is almost over and you will run out of warranty. You need to find the problems soon. Refloating and fluffing the pond loop isn't that difficult. Based on the pics you should have enough pipe there.

ok, I see. That's not too bad then. Since this will be new construction, wasn't sure to have the duct system already in place. How did you find your geo installer?? Glad to know the humidity is taken care of and we don't need yet another thing for that. We have a heat pump now. Is it alot like that? Except for of course the absence of the ugly noisy outside unit by my bedroom window.

Ladia, thanks I believe you have us on the right track. Install is coming out on Tuesday morning (yes, warranty getting close to running out). The heat strips ran all night, they never shut off...when we got up at 6 a.m. it was 7 degrees outside and 67 in the house (thermastat set on 70). By 6:30 a.m. the temperature had dropped to 66. Hubby went down after I told him what you said and shut the heat strips off. When he came back from his route at 8:30 a.m. it had warmed to 12 degrees outdoors and dropped to 63 degrees in the house. He had stuck a meat thermometer in the vent and the air coming out was 59 degrees so he turned the heat strips back on. And the vent temperature went back up to 100 degrees. Hubby put heat strips back on. Sometime shortly thereafter (est 9:00 a.m.)I called him after speaking with geo people and they said to have him turn off the thermostat and wait a few minutes and restart it (i forgot what they said, but it would do something to the compressor???). He turned it off and then back on at 9:30 a.m. it was 14 degrees outside and 63 in the house. At 10:00 a.m. it was 16 degrees outdoors, 64 degrees in the house and the air coming out of the vent was 125 degrees. By 10:45 a.m. it was 17 degrees outdoors and the house had warmed back up to 70 degrees and it's been running either on fan (or Phase 1) only the rest of the day the temperature has been 69 or 70 in the house and the temperature coming out of the vent is 85 degrees. So, my hubby's thought is theat the geo wasn't geo'ing at all until we turned the thermastat on and off. Thoughts?

On Tuesday the geo installer will be here with equipment and do a lot of testing and checking (not to mention I requested a thermostate that will tell me when the heat strips are on). Depending what they find, they may call the sub that did the actual pond loops.

I suspect with the heat strips off, the combination of the low return air temp an low entering water temp caused the unit to fault. Probably on low water temp. If you're currious you may be able to see the last fault from the service menu on your thermostat. You can definatly see it on the control board in the heat pump unit. You might quiz the contractor when they come out.

Will do. Hubby is writing down things to ask the geo installer when they are here on Tuesday. Thanks.

Definitely ask questions about the pond loop.
What is expected flow rate (it is in the installation manual) versus actual. They should measure head of the pump(s) and read the flow rate from the pump chart.
Is the pump sized correctly?
What is the temperature in the pond?
What is the temperature of inlet coolant from pond loop after the heat pump starts running? It shouldn't drop by much. Large drop of the temperature is a sign of poorly performing pond loop.
What is the return temperature of the coolant downstream of the HP. Too large differential between inlet and return is a sign of low flow rate.
What is the pressure in the pond loop?
Is it large enough to prevent pump cavitations?
Was all air reliably purged?
Assuming that the loop is filled with propyleneglycol based coolant what is the freeze protection in the HP set to? If it is set incorrectly (in example for open loop) the protection might lock up the heat pump.
Call another geo installer or technical support of the manufacturer of your system and ask about expected temperature differentials, pond loop pressure, flow rates etc.
Knowledge is power. Don't let them BS you.

One option you might consider instead of having the thermostat replaced is to install an outdoor temperature sensor. This will lockout the heat strips unless the outdoor temp falls below the setpoint. Minimim setting is 5F in five degree increments.

If you look at page 49 of the installation insructions I linked to there is a troubleshooting form that will gather the information to answer many of the questions Ladia refered to.
It would be good to have this information anyway for future reference in case the geo contractor decides to retire and the system needs service by someone else.

I would give the contractor an opportunity to step through this. There are several possible reasons the system is not performing to expectations. THey are all objective.

The geo system may have a problem or not be setup properly. The form I refered to will direct them to that.

The air side of the system may have a problem. Checking the static pressure and the fan speed settings will detect a too restrictive system. Further checks of static pressure and temps can dectect leaking returns or supplies.

The pond loop may have a problem. Ladia covered alot there.

The system may not be sized properly. You said they did a load calc. You can compare.

The building envelope may not be performing per the load calc. This gets a little subjective because they have to do a best guess baring a full energy audit, but were their assumptions reasonable.

MarkECIN, I'd hate to see your power bill for this month. Sounds like you did what you had to do, though. I unplugged my heat strips inside the unit to be sure they never come on. The brain surgeons at WaterFurnace put the compressor on one circuit, and the heat strips and blower motor on another, so I can't just cut off the breaker.

southernbelle, I found my installer at a home show. I am sure any geo manufacturer can give you a list of local installers. I can send you the name & number of my pond loop guy if you want.
Yes, it is just like a heat pump without the big ugly outside thing.

Look HERE

Jersey, I'm sure glad they did put ours on a separate breaker. In all honestly we are confident with our geo installer and their knowledge. I truly believe these systems are quite complicated and as Ladia has displayed over and over again with his knowledge things can and do go wrong. And, boy, are we learning here. Yes, I sure wish I would have disconnected those strips sooner (or been more persistent on the geo person that there still lay a problem besides the transformer replacement by the electric company) and not waiting for their staging question to be answered. Our system was a newer line so I'm sure there is some learning for the tech too. I sure hope I don't get another surprise next month like I did this month (I have even been reading the electric meters and right now my hubby has had to reset the compressor by turning the thermostat off then back on a few minutes later and that seems to reset and the geo then works fine--hardly hear it running. BUT, by far this is a temporary fix until next Monday by the geo people. I will note their findings (so future homeowners who are looking at geo have light of problems many of us have had and learn from our misfortunes.

Question....when things go wrong with the geo system, even if it's not still under warranty, do they help pay on the power bill? If it's something they did or didnt' do? Doesn't seem right for you to have to pay it all if the unit is defective or not installed right. Can't wait to hear what they have to say. Guess the one thing I've learned from this is put the strips on a separate breaker and be sure they are turned OFF!! We have AUX heat on our heat pump and when I see that light come on--I turn the heat down and put on another sweater :~(

Typical geo heat pump has about 400% efficiency (It doesn't make heat it transforms high volume of low intensity heat to lower volume of higher intensity heat.). So if it would work correctly your electric bill should be about four times less.

MarkECIN,
If I understand correctly what you are describing I would caution you about continuous or repeated resets. Unless your contractor has told you otherwise and you are sure they will assume any liability. It's not a good idea unless you understand exactly why the system is shutting down. I would turn the strips back on. Talk to your contractor and get them out sooner if possible.

If the issue of not working is related to the thermostat reseting will not hurt anything. There is a display on the heat pump showing the staus and/or error codes. I woulld suggest to look at the display when it stops working.
In example of Waterfurnace:
The light MASTER MODE and HEATING should be lit while the display shows the temperature.
If the LOCKOUT is lit then the display will show the error code.

It's important that the contractor sizes the unit properly and will warranty that aspect of their services. I would see to it that this is put in writing.



It goes against the conventional wisdom here, but I would urge caution in regard to disableing the strips. It's not a good thing to come back from a weekend trip to a flooded home because the pipes froze and burst.

we rarely have that happen here. We are really in the Deep South! About 2 hrs from the gulf coast. But we do cover the faucets outside in the winter. Can't remember if we ever had any pipes burst except for in an old house we lived in when we first married.....uninstillated. brrrrr

The temperature will not drop to freezing while the house is inhabited. Even if you leave for a day. Going on vacation is another story altogether. So I will rephrase my statement I would virtually disable the heat strips. In other words they should come on only at quite low and uncomfortable temperature.

I'm with you, Ladia. If the geo system was working correctly, the heat strips should have come on only in extreme instances. I know the geo installer had problems with phase settings and called the manufacturer (and we never heard back so we didn't think it was that urgent). Obviously something went bad wrong to have such an electric bill...they should offer to pay back part OR they can give me my next year service agreement no charge. I would have expected an electric bill of maybe $250ish total for the house. We shall see what they come back with.

I hope others, especially those looking to go geo, are reading these posting and learning as I certainly have learned a lot. dot

Service agreement? How much is that a year?? At the cost of these things, they ought to service them forever!! If it's a fault of theirs, sure they will work something out. I'm reading and learning-thanks for your post! Sorry this had to happen to you. I'm hoping we won't have this heat strip problem since it rarely gets very cold here. I'm positive the pond will never freeze!! I've always dreamed of a frozen pond growing up to ice skate on!

I've got to jump back in here and say that I think it is a misconception that a geo system is some kind of complicated, mysterious, or delicate system. It is no different than a run-of-the-mill every day conventional heat pump, except that it exchanges heat in water rather than in air. It is because this exchange is so much easier that geo systems are incredibly efficient. So instead of having a noisy fan blowing cold air through a coil under your bedroom window, you have a coil of plactic pipe soaking up heat at the relatively warm bottom of your pond.

Conventional heat pumps have heat strips too. If there is a system malfunction or circumstances cause the heat strips to come on, the high electric bills will result just the same.

Now if you build your own control system or use a heat pump (geo or conventional) to heat radiant concrete floors, we have a whole different thing going on. Nothing wrong with either of these things, it's just that they would add complication to any kind of system. I intend to use my system to heat 2200 sq.ft. of radiant concrete, and when I do, I'll probably look into building a Rube Goldberg control system for it myself.

When I was shopping for my geo system, I looked at several manufacturers. What I found is that there are no low-end geo systems. They all are high quality units, and this is reflected in their price tags. I went with the WaterFurnace because my neighbor was happy with his, and I got what I thought was a reasonable price from the installer. With the exception of a few start-up bugs with the zone system, my geo system has been out of sight and out of mind. Except when the electric bill comes. That's when I know I made the right decision to pay-up for it.

I would hate to see anyone with the opportunity to put in a geo system, which is almost everyone on this web site, not do so because of a fear that it is complicated or unreliable.

SO glad you posted this Jersey! I had the same impression you just gave.... at first.... that Geo systems are pretty simple, especially the pond loops. I'll admit the more I read here, the more confused I get. I'm not really worried about all the technical stuff-my husband is an engineer and I suppose he'll figure it all out in due time if needed. I sure don't want to spend this much money and have all these problems! I'm sure like everything else there will be a few minor problems. We will probably go with WaterFurnace also, mainly because you use it and don't seem to have many problems (and also that we are in the same zone). I wondered too if there were any 'bargains', but I see they are all going to be basically the same. I'm content with the fact that we are able to use the pond and will save a bundle there. We are going to put off building the cabin a while until the economy picks up a bit, in case we need to help the kids out. The pond is still on, soon as they can get out here. I've learned SO much here and sure I'll be around when we start this pond. I get more excited every day about the Geothermal, which we have pretty much decided we are doing. Jersey-at what point do we need to contact the company? I was wondering since we will have a basement, should we have tubes or anything else under the slab?? I'm wanting to leave the concrete and stain it, using throw rugs. I know it will be cold down there. The main floor will be all wood floors.

southernbelle,
I put pipes under my basement slab for the geo system, then the loop guy told me they were the wrong size, so he ran new pipes overhead. I wish I had contacted him earlier. So the answer is YES, invite the loop installer over before you pour the basement floor. You also might want to look into putting PEX in the basement floor for radiant heat. It doesn't cost much, and you only get one chance.

Thanks! I'll look into that. It's possible we may go ahead and start on the foundation ahead of time, so glad you told me that. I guess when they come they can look at our plans and give us an idea on what to do next. Tell me this, does radiant heat make just the floor warmer or help warm up the room? I think I remember you mentioned this was a whole different set up from the geo. How does this work? Is this a do it yourself project? Do you think we will have enough hot water in the winter to run this? I found this site on the PEX diy http://www.pexheat.com/

The geo systems are somewhat more prone to initial problems due to the fact that the ground or pond loop has to be correctly calculated, has to be made in the installer's shop and has to be correctly isntalled etc. In other words the experience and skill level of the installer is important. Also geo might have several more heat exchangers with associated pumps and temperature control that are all based on the particular house. In other words there are more components of the system that are custome built or at least custom configured.
Air based HP are factory made and therefore all the componets should be well matched and asembled correctly.

I would recommend PEX with oxygen barrier. It isn't needed for geo but you might add in example wood boiler later on. Oxygen barrier is important for corrosion protection at higher temperatures that boiler can produce.

Heating the slab will warm the whole room. The best part is that the room will be warmer at the floor (where your feet are) than at the ceiling. I would not expect to get enough hot water from the geo system for this, but I could be wrong. The geo only makes hot water when it is heating or cooling air for the ductwork. There are geo systems that only make hot water, but this is a different animal. In the winter, I use all the hot water it can make for showers and domestic use.

I would not recommend installing the pond loop pipes yourself. Not because it is difficult, but because they use a specific type and size of pipe. The installer will probably go ahead and run the pipe all the way to the pond while he is there anyway. Installing the PEX tubing took me the best part of a day to put down 1800 sq ft in my basement floor.

By the way, I know this might be different around the country, but my system has 3000' of 1 1/2" pond loop. The rule of thumb for our climate is 500' per ton.

magic heat Pumps

don't rememeber if this has been posted here

http://www.motherearthnews.com/Renewable-Energy/2005-04-01/Geothermal-Heat-Pumps.aspx

I love this magazine--been reading it for years

We have the same rule in Iowa. Out system has 2500 ft of tubing in the pond and about 800 ft in the ground. We had only puddle of water in the pond our first winter in the house. Top third of the coils was sticking above the ice but the house was still warm. Inlet temperature to the HP was around 26F for about a week during a cold spell. The coils were apparently covered in ice to the bottom.

On a note, here in mid central Indiana our pond did freeze over for about a week--we had some pretty extreme single digit temperatures for awhile. We think we are going to put two aerator stones out this year vs the one off of our windmill--may or may not help. The cost of a service agreement is only a couple hundred a year. Now your loops are usually 10 years (you have all your regular manfacturer warranty on your system etc). On the problem we were having with the heat strips on, sizeable electric bill this past month and probably one more--the geo installer came today and spent a couple of hours doing analysis readings and the like checking everything out. The unit seems to be doing what it should at this time. As Ladia noted there is a lot of adjusting that has to happen based on each persons individual circumstance. One thing he brought up that will be looked at is the 'fluff' of the coils in the pond along with an analysis of all the readings. I have faith it will all come out fine in the end. We are installing a newer Carrier thermostat that will tell us exactly when it is stage 1, stage 2 and stage 3 along with when the Heat Strips kick in - Yippie! One must remember when you live in extreme climates in the north, there will be occasion that the heat strips may engage so you don't want to turn them off (you're just hiding some other unforeseen problem you probably have with your geo). I will let y'all know what the end results are so others who are going geo can be conizant of things that can and do go wrong while tweaking your particular system. Honestly, the price I paid for geo is a bargain compared to what it will give me when it pays for itself in 4 more years. dot

I would still turn the heat strip breaker off but watch when and for how long the thermostat would turn them on and what is the effect on comfort while they are disabled. If they wouldn't come on at all or very seldom only then I would turn the breaker back on. Provided that the heat pump is working properly disabling the heat strips shouldn't have noticeable effect on comfort.

We know the solution coming in from the pond (temperature-wise was too cold) caused the geo to not geo. Hope to get a fix on that. Should have that thermostat in in a week or so and be able to visualize changes.

The moral of the story is that it doesn't matter how much tube you put in the pond if it isn't installed (fluffed and/or purged) properly.
I have never seen aerator stones in a pond in action but, if placed under or in close vicinity to the coils, they might promote water circulation trough the coils. It is just an idea. Maybe somebody can tell us if it is worth considering.

I'm thinking you're on to something, Ladia.

http://www.mercomarine.com/gallery/floating%20house.html
Here is a link to a floating house for inspiration

I've got a guy coming out tomorrow morning to discuss the viability of going geo, using the north pond as the heat sink. I already understand that one of his first steps would be to measure/evaluate my home in order to properly size the system.

What else should I expect on this first meeting? Any suggestions would help, as I've no real idea how this all works...shooting blind here.

On the bright side, I found him on the Iowa IGSHPA (Ia Ground Source Heat Pump Association) database. Hopefully, that means he's good...don't know, though.

Me thinks so too!!

Matt, please do post what all he does and says. I think we may need to get them out before we ever start building.

Ask for references, then call those people and if possible go and see their system.
Some of the local utilities also sell and install geo and/or might know an installer with good reputation and track record.

Well, that's interesting! Guess you don't need a septic tank?

By the way the house has most likely geo with floor heating.

Hey you guys....
Tell me about putting pex into a slab. I wanna do it with the shop area of our upcoming garage/apartment project. The entire garage and shop area is 28' x 44'. The shop portion is at one end: 28' x 27'. From what I'm reading, the correct procedure is to compact the gravel base and lay out the vapor barrier. Then, cover the entire slab area with 2" foam insulation (the pink stuff). Set the wire mesh on bar chairs to keep it centered in the slab and tie the pex to the wire mesh. Set the pex run to start and stop as close as possible to the hot fluid source and form out a small area in the slab to install the manifold. Pour a slab. I'm thinking 4" thick.
Thoughts? Tips?

Brettski,
I was looking for some more pictures, but I couldn't find the ones I wanted. This is one corner of my basement slab where I stubbed in for a future bathroom. Where there is no PEX is under the utility room. To the right side of the picture, you can see the pattern I used throughout the 30x60 basement floor. To cover entire area I used six loops, each about 200' long if I recall correctly. The wire mesh is 6x6, so the tubes are spaced about 12" apart. The blue vapor barrier has insulation in it.

What diameter pex is it? From what I've read, if I use 3/4" i.d. I can space it about 16". That would work great since a 500 ft coil would do the entire area in one run.

I don't think it is a good idea. You will have large temperature gradient between the tubes (the middle will be much colder. Also 1/2" is easier to handle. It is also good to have some built in a redudndancy for the case one of the loops gets damaged. Beside that you will save, in scope of things, negligible amount of money. There is also a plastifier (additive) to the concrete to make it better contact the tubes without bubbles and gaps. Didn't hear about it in the USA but we always used it in Europe.

Thanks Jersey
-
Ladia,
That's the kinda input I seek. Thank you. Considering we are talking about a slab area of 28' x 27', what would you call a good idea for amount of runs of 1/2" id?

The general rule is to have all loops associated with particular manifold of similar lenght. I think about maximum 200-300 ft long. Some of the manifold (in ex. Rehau) have built in rotameters (flow meters) for each loop so adjusting the flow and balancing the loops is very easy. It is better to err on the short side I suppose. You can always limit the flow of short loop but not necessarily the other way around. As I said before I am just informed amateur so ask the proffessionals for second opinion.

Brettski:

Did exactly this for a 30x40 pole shed workshop for my best buddies ol' man. WORKS GREAT! Used 4 runs of about 300' each, 1/2" ID Pex, spaced at 12" OC...about 1 foot of tube per square foot. 300' per run is about max, otherwise you can't use the cheap (readily available) TACO brand, $100 pumps...not enough head to overcome flow resistance. Much longer and you have to step up to 3/4" tube and "High Flow" pumps.

We started 6" from ext. walls, and alternated flow (first run CW, second CCW, etc.) but you can do that with how you hook up PEX to manifolds. Just start wherever and make loops leaving enough tube to reach back to the start point. For us, it's all one "zone".

Not sure why folks want the manifold in a box on the floor...I mounted manifolds on the wall and ran tubing up to it, but it's a shop so we didn't care about "hiding" all that stuff.

Make sure your insulation is rated for below grade work, and High Density...AND make sure you insulate the heck out of the edge of the slab. We messed up a bit...snow melts away from the slab outside, so we know we're losing heat, but it still only takes $50-75/month to keep the place at 70F+.

We also used these plastic clips (google PEX screw clips) that twist into the insulation to attach the tubing. Laid out rebar on top of that...never have to worry about puncturing that tubing later as it's in the bottom inch or so of 5" of concrete.

All was bought locally at Menards...maybe a grand for everything, including the 50 gal gas HWH. I'm doing this in my shop this summer, too.

Had the first guy out to bid on this...may not need to have anybody else out...

He did all the right stuff...measured every window and door, square footage of house, took pics of existing HVAC equip, asked about fuel/elect usage, types/quantities of insulation, "any cold/hot spots?"...and was taking ALL THAT back to his (get this!) engineer to actually calculate what I'd need. They will work directly with local Elec coop to ensure I get an acceptable install to qualify for rebates and install separate meter to get lower rates.

We talked about arial pics (he says they usually have them, but they got left out of his "directions" pack) and I just emailed a link to 09/08 set so he can share them with his "dirt guys" to work out best package (which pond or use trenches).

Later, I was talking to the Elec coop guy and turns out they know these folks well...they recommend this installer to customers when they need troubleshooting done or just a third party opinion when there are performance issues. This guy was also expounding on the cost savings HE gets with his system.

Gaining confidence all the time...wife says this and the shop have to wait til after the daughter's wedding in May. Dang it...now I'm excited.

Thanks Matt,
Yeah, I did pick up on insulating the edge. I have a good link to a site that describes most everything you guys have pointed out, right down to the plastic clips that stick into the insulation.
I'm having a hard time believing that the slab (with the 2" hi density insul supporting it) would have the nuts to adequately support the weight of vehicles, trucks, and implements. It just don't seem right. I'm sure that upgrading to rebar would provide improved lateral distribution of the point loads, but is that the reason...or...is the foam really strong enough. Sorry, but I just can't buy it.

If you just make sure that your subgrade (stone, sand, whatever) is properly compacted and level, it has no problem supporting anything. My concrete guy suggested I add a couple inches to the floor in case I wanna pull the tractor in the shop. 7000 lb Farmall 560...

Type V XPS has a compressive strength of 100 psi. I'll probably go with Type VII, at 60 psi which is plenty strong. Tractor with concrete would only be about 30 psi or less...

no way! I might have to have one of these. You going to build one? Might be fun to build a one room guest cabin like this. Just a bedroom and bathroom, maybe little frig. Guest would be talking about that for years!

If we took your 7000# tractor and divided the weight into the 4 point loads (bearing points at the tire contact patch) we would get 1750# per tire (this is not an accurate distribution of the weight, but good enough for discussion).
OK, a 1750# load onto a 100 psi max support would require a minimun of 17.5 sq inches of even distribution...or...a contact patch of 3.5" x 5" minimum. This all assumes that you are pulling the tractor right on top of the insulation and the point load is evenly distributed across the contact patch. I don't know what the contact patch size is for your tires, but I bet it exceeds the 17.5" min at all 4 corners. This is good, but it illustrates just how close you are to exceeding the support capacity. Now...let's add the concrete and reinforcing. Yes, it adds some weight to the foam support, but it is relatively negligible. It all comes back to the lateral distribution of the point load by the reinforced concrete; just how far it pushes the load out radially. I don't know what that calc is, but it illustrates how vital it is in the big picture of load support for this application.
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...did I get that right?

Bski, buy a sheet of the foam and drive the truck onto it. See what happens with a (near) point load. Then distribute with a sheet of 3/4" plywood or a large board. Extrapolate.

I would also recommend putting manifolds on the wall. My manifolds are in the utility room and one in the closet. I would also suggest usage of manifolds with flow meters built in. They are very nice for setting up and especially for troubleshooting. I have three zones (on the far end of the house) controlled by servo-valves. One of the valves developed a short in the limit switch while ago and overheated one zone. Checking the flow meters revealed the bad one just by looking at the manifold.

http://na.rehau.com/files/Brochure_about_manifold_components.pdf

Brettski:

I am planning on doing the same thing (radiant heat in a shop floor) but I'm going about it a bit differently. Here's my plan and why I'm doing it this way.

My radiant heat company suggested 5/8" tube. They also suggested that because it'll be in a shop, that it should be installed directly on the foam. There is a gun that staples the tubing directly to the foam, and that is what they recommended. On advice of my concrete guy, he recommended a 5" thick slab. From what I've read, and what the radiant people preferr, is NOT to use wire mesh, use rebar instead and put it on chairs to get it in the middle of the slab and up off the tubing. My concrete guy agrees. He said #4 rebar on 2' centers, if I want to make it stronger, put them on 1' centers. They (radiant people) prefer rebar because 1)it won't be smashed into the tubing by the workers walking on it when the concrete is poured and leveled, therefore minimizing any potential punctures, 2) the tubes will stay on the bottom of the slab where they belong.

The concrete guy liked the idea because his guys wouldn't have to pull up the mesh to try and get it centered in the slab like it's supposed to, and he said that the rebar spaced that far apart would let his guys step between the bars. The radient people said that stepping on the tubes wouldn't damage them providing the workers didn't "jump up and down on them". From working with concrete out in california, in addition to the rebar or mesh, we had the fiberglass "hairs" mixed in the concrete as well. My boss said "the fibers will stop any surface cracks, but it's the steel that gives the concrete it's structural strength." I know of 2 different buildings here in Indiana that were poured that way, one with radiant heat in the floor and one without and neither of them show any signs of cracking where it wasn't supposed to crack.

So, I'm going with 5/8" O2 barrier Pex attached to the foam, #4 rebar on 2" tall chairs, 5" slab with fiber reinforced concrete.

Manifolds on the wall too. BUT, from what I've read, there aren't any UV sabilizers in the PEX tubing, so any that would be exposed to sunlight need some sort of UV protection, whether paint, inside a closet or some sort of sleeve. You know that the PEX should be in a plastic sleeve when it transitions from horizontal to vertical, right?

Thanks esshup; good input.
The issues with mesh being "pulled up" in a slab is one of the oldest in the book. The only time you can feel somewhat assured that it was done correctly is when you pour the slab yourself. Even then, it's not as accurate as rebar on chairs. If you saw my threads on the boat launch and our shed, you'd know that I'm a rebar guy. I oughta be; my first job out of high school was making shop drawings for placing and sizing rebar for architectural drawings. Working in a steel warehouse that fabricates rebar helps, too.
OK, so it's rebar in the slab. Believe me, 2' o.c. is unheard of. It's 12" O.C E/W.
I agree about the 12" o.c to aid in navigating the pour zone; been there, dun that.
5" slab; no biggie. Fibreglas additive; jury's still out, but I'm not opposed to it.
Yeah, familiar with the staples. I know squat about the thermodynamics, but assumed having the tubing centered in the slab would make more sense. I can see the "radiant" wisdom in sandwiching it between the slab and the foam insulator layer. 5/8" ID, eh?...

Tubes located deeper in the concrete will result in more even surface temperature and are less vulnerable to screws drilled to the floor.
To locate the tubes in the concrete you need a friend in the fire department. They have infrared imaging camera. It works very well. You can also use infrared thermometer, push the trigger and pass it over the floor and watch the display. The tube is just below the maximum temp measured. This works best when the floor is turned on after few days of being off.

Here are some pics of my radiant install in 2000 sq foot walk out basement in house I am building. Keys points for me when installing radiant:
- try to insulate the slab (bottom and edges) and install tubing closer together on perimter edges.
- worry less about about tube spacing but DO get all the tubing in the slab that the specs call for.
- pressurize the tubing with air before concrete pour. If you see bubbles, scoup out the concrete from around the damaged area ... you can do the tubing repair and patch the concrete spot after the rest of the pour.

1st picture shows tubing stapled to foam and rebar on chairs ready for pour:


Remember to steer clear of toilet wax rings or you might melt them!



Manifold Picture:



I hope this helps. I am setting up a driveway snow melt next week and will try to post some pics of that set up as well.

Thanks Nick; well done, sir. Those pics really tell a story. I assume the areas with the spray foam insulation are the rough plumbing where the top/pipe is slightly higher than the sheets of foam. ???
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(edit) What ID of pex did you install?

Brettski,

You are correct on the spray foam. We use a seperate 6 mil vapor barrier so we spray foam any irregularities caused by plumbing rough in or structural components. The tubing is 1/2". While I do not discourage folks from have tubing projects engineered, we have found that 99.5% of the time 1/2" pex on 12" o.c. and 6" o.c. on exterior perimeter walls in a properly insulated slab will meet normal heat load requirements in west central MO. When we do exterior snow melt, we use the same above rules and step up to 5/8" pex (3/4" works better but is hard to justify the expense).

I found a couple more pics:

Vapor barrier install before foam (blue pipes are geothermal header pipes stubbed up at future mechanical room):



2" foam insulation install on floor (1" @ perimeter where floor slab meets foundation wall):




Hope this helps.

Nick

Brettski,
Sorry for the delayed reply...

It is 1/2" PEX. I used ty-wraps to secure it to the wire mesh. I think everything else has been covered. Try to plan ahead on whether you might want to zone off any areas, and run one of your loops into that area. Say for instance, an office area in your workshop. You may never zone it off, but the option will be there. I wouldn't worry too much about damage to one of the loops. That PEX is really tough.

Also, Google "Grundfos UPS15-58". This is a 3 speed circulator pump that is perfect for this kind of application. I got one for $35 + shipping.

Nick added a very important point. Pressurize the PEX before the pour. I put 40PSI in and watched it hold for 2 weeks before the pour.

Next week the loops in the pond will be floated up and more 'fluff' as Ladia called it--added. They will also for sureness as they have to float it up anyway to the surface--they will add another loop.

My techs will come out again when the loop installer is here and make sure everything is in sync again (and of course, add my new thermostat that will enable me to know when heat strips kick on ).
Thru the trials and tribulations, I still would highly recommend my geo installer. I'm learned so much since installing geo.

The tax savings for the geo we installed last year is an added bonus.

Pictures, pictures, pictures!!!

Sure will. I plan to leave work to watch it myself as I missed it all when initially done.

Unfortunately I am out of home and don't have pictures of properly "fluffed" coils on my puter. They should put several spacers (About three pieces of 1" plastic pipe somewhat longer than diameter of the coil laid across the diameter of the coil. Like spokes fashion.) between every layer. In other words each layer has to be separated by spacers at least on six points. Turns of each layer should be also separated so the water could flow freely through them. It is a lot of work and might require cutting off one end of the coils from the main pipe to allow for unwinding of the turns. They should place the coils somewhat higher than the deepest point of the pond. Every pond gets silted and you don't want the silt restricting flow through the coils. If your pond is deep enough the coils could be placed few feet above the deepest point. The water is also somewhat warmer at that location.

why are they having to do all this? Was it not installed right the first time? How long have you had the geo system? Glad you are finally getting it fixed! maybe next winter will show a big difference in power bills. We still plan to do this....IF we ever get this pond built!!

I am just guessing that it is "the lowest bidder syndrom". The geo installer subcontacts the loops to the lowest bidder and they, in order to make money, hire inexperinced people and cut corners. But at the end it is a responsibility of the geo installer to make it right. The moral of the story is that the lowest bidder isn't always the cheapest one. In the better case they are just new in the bussines and hopefully learn from the experience. There is more to it than throw five coiled bunches in the the pond.

Make sure the pond holds water before you put the coils in. In opposite case you might be better off installing ground loops.
To limit digging find a contractor that does horizontal drilling.
http://a-onegeothermal.com/horizontal.html
I think it is also cheaper than digging

The coils were similiar to those we'd seen pictures of(I have a feeling I'm far from the only one whose loops could use more 'fluff'). Actually, two bidders were the same and it came down to the one we chose; pretty much all geo pond loop work itself goes to a couple of installers out of Indy (maybe he wasn't watching them close enough and maybe we weren't smart enough). Our geo techs use the same loop persons and has a good work relationship with them. You know how that goes--live and learn. In the end, it will be fine.

The correctly "fluffed" coil should allow for free flow of water between the turns of the coil. The flow is generated by thermosyphoning. Since the temperature differential is just few degrees the flow is quite slow. Because of slow velocity of the water effective heat exchange requires large contact surface. Therefore the correct fluff affects overall efficiency of the geo system especially during high load operation. I understood that you are going to use aerator(s). Placing them under the coils should definitely improve the velocity of water in the coils. As I said before fluffing coils correctly takes quite an effort and time (lot of cable ties and spacers). In general the individual turns shouldn't touch each other and be at least 1/2" apart. You should be able to see trough the coil looking down as well as horizontally. Later on the coils gets "polluted" by algae and other stuff living in the water. If the turns touch or are too close the stuff will plug the passages and the efficiency of the coil will decrease. It always happens few years after warranty expires. Do not take "This is how we always do it for an answer." They might be doing it all wrong all the time. By the way the more I think about that I should refluff my coils too. Warranty is expired so I am on my own.

i would like to refluff my coils too

Interesting, Ladia. So how often you think a 're-fluff' should occur? We did have our aerator in the vicinity but it has since moved so we will be putting two aerators out this summer. The initial one we had in a bucket of rocks but it probably tipped over or the current moved it as the bouy is close to the bank now. This winter was extremely harsh with winds and we've had some erosion along the edges of the pond and dock that I need to take care of this summer. I didn't want to put rip-rap (cosmetic) but I think I best do so.

It is important to fluff the coils properly first time and they will perform for many years very likely for life of the system. My coils are fluffed but not perfect. I think they might possibly plug. I need to drain my pond for leakage repair so I will get a chance to see how they look after about four years of operation and fix them if necessary.

will be interesting to see how they look once you drain the pond. Take pictures!

For ours, when they drain some of the solution out of the loops, the loops will actually float to the surface and they will pull them to shore. It was pretty interesting to see it sink (says my hubby). He will be watching tomorrow again and taking lots of pics.

Well, got my first quote last week and the second vendor is supposed to deliver this Friday.

First guy says "we do many pond loops...maybe 10% total". However, I don't see that in the quote, specifically, especially the digging part to get to the pond. ($15500 before REC rebate and tax credit.)

Second guy says "we specialize in horizontal boring" but they'll quote it both ways. He says they do one 200' round-trip bore per ton capacity. Before calcs, his experience leans to 3-4 tons...and EACH bore is $1300, plus $1200 to get into the house. That's $6400...I can't believe pond wouldn't be cheaper and more efficient.


More confused than ever...

When I got my quotes, I thought the same thing...but the pond loops didn't come in cheaper. I even considered ground loops (but didn't want to tear up the yard again). When they give you the quotes ask them for the details --the unit make, model, capacity etc. etc.----you know all the good stuff that they don't want to share with you as they know you're 'shopping'. Mostly, they sub out the pond looop work so I wouldn't be surprised if digging ground they didn't sub that out too). They shouldn't have any 'hidden' costs from you. I was lucky enough to have a sizeable rebate in Indiana that I was able to take advantage of too. Good luck, no regrets going geo here...mine were reputable and stand by their warranty, good people to deal with.

I think it is standard procedure that the loops are put in by someone other than the HVAC guy. My pond loop (3000') is about 200' from the house. The guy installed it for $7000.

Well...it sounds like the hor. boring is at least comparable to the pond loops, price-wize (already know both org's contract out the loop portion). I like the boring thing from the standpoint that it's WAY less area torn up...only about a 8 foot cube near the house, and we can "point" them anywhere I want. Plenty of room here.

The "contract" I received as a first bid isn't very specific...I'll ask for more details if I go with them. I want make/model, as I've been looking at on-line reviews of many. I realize it's not perfect, but at least I can see some weak areas for some units...

...and my REC offers $1650 rebate off the top, plus $300 for the HWH. With Fed tax credit (as long as it meets the criteria...a CONTRACT mandate) that's 30% of the total project cost. About $4800 total, so that gets it down to around $9500. Steep, but I spent $2000 on LP alone this year and Electric avgs $160/month.

Make sure that the HP is optimized for your climate and heating system in ex. forced air or floor heating. In example if there are more AC than heating days the HP should be optimized for such operation and vice versa.

Ladia:

I'm about where you are...maybe 2 hours east. Not sure, but I think heating degree days are more critical that cooling. Am I wrong?

I don't know exactly the design issues but there is a difference in the geothermal HP depending on the purpose such as a pool heating in Florida or heating a house in Canada and anything in between. In other words it is the best to buy it locally.

Ladia,

What is an approximate cost per ton for a system?
I have the room for horizontal loops and excavation tends to be pretty reasonable.
I'm located in SW Pennsylvania.
Did a load calculation on a geo-site. Came up with 200,000 BTU heat load, 112,000 cooling load. It's a big house, built in the 1930's.
This is a potential purchase and I'm figuring I need to do something like this instead of having a huge gas heat bill....

The cheapest heating is insulation. Geothermal heating is currently the second best. You might need two or three large units for such a house and that could add to the expense. Improved insulation could lower required heating capacity for less money not speaking about lower future energy consumption.
I don't remember how much we spent for our system and partial installation cost. We did a lot of work such as AC installation by ourselves and still spent in my estimation 25 to 30000. The 5 kW (about 4 ton) heat pump itself was 5000. We have both floor heating and forced air-cooling and that adds to the expense.
200 000 BTUs that is about $350 in energy cost (with geothermal) at coldest month at rate 0.041/kWh. Direct electric heat would be about 8 times as much.

The H/C contractor was just out here in preparation for a quoting a geothermal system for our home.

We are talking pond loops rather than ground loops. Our soil below the frost line isn’t soil, it is sand and gravel. The contractor said that sand and gravel isn’t very efficient for ground loops and that pond loops would be the way to go for our location.

There a several reasons that we are a considering a geothermal system at this point in time.

* Tax credits
* Electric Coop credits
* Current H/C system is near the age of replacement.
* The cost of LPG is outrageous when you heat at least some of 7 months of year.
* Gail likes backhoe trenches in the back yard.

I think it will be a no-brainer for us with payback in 3-4 years. The quote will tell the story.

You're lucky man, Dwight!

How big is your pond? You need enough water so the geo would have only small effect on the pond environment. I read somewhere you need at least 1ac 6ft deep or equivalent volume for about 4 ton unit.

5 acres, 10 feet average depth,16,300,000 gallons.

Fantastic.

I have a 5 ton Geo. Pond loop installed in 1/2 acre pond max depth about 9-10'. No significant changes in pond temp. compared to similar ponds nearby. Bottom diffuser aeration isn't significantly affecting efficiency but I don't aerate between November and February. Whole house electric bill last month was $100.43. Worst bill was this winter and a little over $300 but the thermostat was set at 74 degrees most of that month 24/7 and temps outside were often below 0. Going off memory, I think the pond loop install was around $1300, about a third the cost of a ground loop in 2003 but I don't think trenchless was available then. I looked at my loop this past winter with my Aquavu while ice fishing and it is still surpisingly clean and the blocks it's sitting on only appear to have sank about an inch. This might have something to do with aeration.

First contractor said "No problem...we can use the pond."

Second contractor (and a third that I've not talked to, but just randomly mentioned to wife) says my pond (1 acre +/-) is "...too small to be efficient..."

Course, the last guy is just an idiot kid I've known for years, and he's just a gopher for one of the main dirt contractors around here.

Whaddaya think? Is 1 acre in SE Iowa too small? Not from what research I've done...but I don't claim to know much about this stuff.

I don't think it has anything to do with efficiency. We heated our house just from a puddle our first season and it wasn't more expensive than when there was more water in the pond. I am just guessing if the pond (volume of water) is too small then the geo might increase/decrease water temperature by few degrees and it could possibly affect the environment in the pond.
See the quote:

In my opinion your pond is big enough.
Assuming theoretical 1ac 6ft deep pond perfectly insulated with no heat loss.
1ac
sguare ft 43560
depth 6
cubic ft 261360
lb of water 16260349
BTU/degR 16260349
48000 BTU unit will increase the temperature by one degree in
339 hours.
Hope it is right.

Matt,
I'm not an expert on HVAC, but I cannot imagine that your one acre pond would be too small to handle 48,000 BTU of heat. I think the heat load would be completely insignificant. Think about it this way, what if you were trying to heat your pond like you would a swimming pool. Do you think this 4 ton system would make a difference?

Why don't you call the equipment manufacturer?

Matt,

WaterFurnace corp. headquarters in Ft. Wayne, IN. has a one acre pond with loops sunk. They heat their entire building with those loops and that building has got to be 100,000 sq ft.

You say my pond's too small??! Them's fightin words!

Today I placed buoys in the area where the pond loops go. The contractor says 6 feet is deep enough. I say 10 feet is where I want them. We are going with the 2 stage variable speed GEO unit.

Great pond.

Thank you.

Sounds like the one contractor would just rather NOT deal with a pond loop. For that, he gets a thumbs down. The first vendor was happy to do pond loops or trenching...made no difference to him, as he contracted it either way.

Wonder how the contracting out affects any performance warranty?

Either way, I'm getting closer...daughter's wedding is 5/9...wife says this (AND my new shop) have to wait til after that, but I did send out for bids on the shop to a contractor this AM...

My system is a GT-PX Two Stage Puron Serioes (pond loops). It has been inplace 14 months. This happened Friday, a HVAC person came, but with the Holidays they won't be back until later to spend about 2-3 hours looking over system. The geo stopped cooling and it was like 83 outside and 78 inside. The HVAC changed the filter (which they were to do sooner but had to order some); the tech wasn't the regular geo tech (that one is off for Holiday) and he tried to say the filter was problem. Now that I think about it he turned system off and then on later and maybe that is why it worked for about 30 minutes. Of course Sat. morning I called them again as I had to shut the unit down and restart about an hour later and it would work again for a couple of hours. It's the weekend continuing and I'm still turning the unit off and on about an hour and restart if house gets hot. Hopefully, the real geo tech will be out Tuesday. Any thoughts as to what might stop the geo from cooling??? Is there some type of valve that would cause this problem...has anyone experienced this problem? Thanks. Dot

I installed a 3.5 ton unit in a pond that is less than 1/4 acre and 12 feet deep. I installed the entire thing myself and my highest bill so far has been $160 on a very cold month.

http://www.geothermaldiy.com/

Wow...I'm impressed. Probably not something I'm willing to tackle on my own, and shudder just even WRITING that down, because I do EVERYTHING on my own.

I simply travel from home way too much to put something like this in and not have a local vendor familiar with the system to take care of it if something goes wrong.

That being said...got any pics? Love to hear more about your experience.

I don't have any pictures, but the one thing this kit offers that a lot of the professionals don't have available is the loop kits pre-made with fittings on the ends already. They are precharged with anti freeze and have quick connects that plug right on the manifold assembly. I built pvc framework out of plumbing and tie wrapped the loops to the frames. There is one loop per ton so I had 3 loops.(I must only have a 3 ton unit) Anchored the entire framework with concrete blocks, floated them out in the pond and let them sink. The rest of the installation was pretty easy, a little wiring and plumbing. My HVAC contractor came out and ducted the house down to the unit and that was all she wrote. I know what you mean about not having the local support like an expensive name brand. So far, not a single problem and my HVAC guy is pretty sharp and I have faith that he can work on this if there are any problems. Either way you look at it, a year is about all the warranty you get with any of these systems. I figured I saved at least $7000 with this DIY kit.

How big house do you heat? Do you have separate meter for the geo? What is your heating electric rate?

I have been to that website more times than I can remember! Wow, now I have somebody to use for a barometer. Can you provide a short summary of the entire excursion, including some installation details and how you got there?
Thanks, wazzle. I am seriously interested in your project and results.
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(edit) Better still, if you have the pics and the time, I encourage you to open a new thread of your own and take us along for a ride on your installation. Pleeeeease???

Geothermal makes perfect sense. However data trumps theory every time (sorry I am a scientist). The fact is that geothermal will on average cost you more money than conventional heating and cooling. It should not be the case, but on average it will cost you more. Each piece of hardware should be relaible but it is not. You will, on average, outspend any savings on the well-designed use of geothermal energy on maintainance costs for the units. As I said, this should not be the case, but it simply is the case.

So, you are a scientist for some LPG company?

Just a lowly biologist. I would love to install a geothermal unit if they were reliable. Had a friend that swore by his until the last couple years when repair costs ate up all his savings, not to mention being without heating or cooling while the techs kept replacing things. The finally replaced a $80 part at the cost of $1000 because the labor to disassemble the unit to get to the part, and then reassemble was horrific. I may assemble my own open system sometime just for cooling using a 30-foot well near the house with an increadibly high flow capacity. Should be free cooling except for the pump and fan.

I will try to get some pictures of the unit and plumbing and post them, but for some reason I didn't take any of the loop installation. I am heating and cooling a 3400 sq ft house with 3.5 ton unit. I do not have a separate meter for the geo. Now, before you say whoa, that is way too small, my house is built with ICF's(insulated concrete forms). The basement has 2.5 inches of foam inside and out with 8 inches of concrete, the first floor has 2.5 inches of foam inside and out with 6 inches of concrete and the two bedrooms on second floor are basically in attic space with insulation packed everywhere. My average monthly bill ranges from $80-110 with the high of $160. Now while I will agree with one of the posters that the extra cost of geothermal outweighs the cost savings in electricity, the installed cost of this unit make a big difference in that savings. The major cost difference in geothermal of course is the loop installation. I have been told that loops are good for approx. 50 years. Therefore, if I have to replace my entire unit inside the house, my loops will still be there for that unit. Installing loops in a pond are by far the most inexpensive method as opposed to the underground loops. One thing to consider is the distance from the unit in the house to the pond. This company offers different length loops but there is a limit to the distance. One option that is available is to have the loops converge in another outside location and plumb two lines, supply and return, from the manifold to the house.

Since they are essentially the same in principle the geothermal heat pump is about as reliable (or unreliable) as standard air conditioning unit. The extra expense for ground/pond loop is paid by energy saving.
We used to have standard forced air furnace in my former house. I was changing the igniter about every other year, fan motor once, refrigerant leak once, thermostat once and few more issues I don't remember. All in about 9 years.
We have geothermal in our new house for past 5 years and so far didn't have to replace anything except one pump that was too small for the load. I spent about 500 USD on new control system but it was more or less optional. I just liked the project.
We heat almost 4000 sqft and our electric bill in the coldest month was about 100 USD. Colleague of mine has a house of the same age but half the size and his NG bill was 350 USD in the same period. My estimation is that we save minimum 600 USD/year on energy.

NOT COOLING - FIX: Got my geothermal unit looked at today, all is well again. It was a small defective sensor gone bad--under warranty.

Good.

Anybody know of any good, reputable Geo contractors in Arkansas?

Chad

Love the old post from "Asleep at the Wheel" but he does not come around PB any more it appears.

Gathered lots of good info here but am looking for a competent North Texas installer & curious if anyone has any knowledge of Hydro-Tech?

http://www.firstco.com/firstcoimages/pdf/wsvx.pdf

You can find a local HVAC Contractor in your area at http://www.airconditionerfeatures.com/location.html. Some HVAC Contractors do not handle Geo-Thermal systems so make sure you ask any contractors you speak with how familiar they are with working on Geo-Thermal systems.