Pond Boss Forums INTRO Questions & Observations Geo Project

Our geothermal project has begun. Phase one was completed on Thursday in about 8 hours.

While the backhoe operator dug the trench for the 2 inch ID 200 foot long feeder pipes, the HVAC contractor’s guys were working the pipes.















The 1600 feet of ¾ inch geothermal pipe for the pond loops is laid out.



Loop segments are tied together and fusion fitting of the loops, manifold and 2 inch feeders are completed



The sealed (hopefully) system is pressurized and after lunch checked to be sure.







The pond loop assembly is moved out on to the water and 6 weights are added around the periphery.



The Barge (run by me) tows the pond loop assembly out to the predetermined 10 feet deep area. The system is filled with water and the loop assembly settles to the bottom.



Back filling is completed.







The feeder line openings are sealed.



Phase 2 follows in about ten days. In the mean time I need to run the two 220 volt circuits required for the heat pump and the auxiliary heating unit.

Good photos. I have a few questions:
- how deep was the trench leading up to the pond?
- is anything done to keep the coils in the pond from moving around?
- I assume you are replacing an existing system. If so, did you compare costs for replacing the old system with a conventional one? (I'm curious about upfront cost comparisons)

Thanks. I'll be interested to see more as the install is finished.

The trench is at minimum 6 feet deep.

The coils are held in place by their own weight filled with fluid and with 6 large concrete weights around the outside of the loop assembly.

Compared to our old system (a high efficiency LP furnace and an older AC unit) the annual savings in energy costs averages over $3000 per year. This includes the savings accrued from moving the house HE furnace to the shop. The shop currently has an old LP furnace with a chimney.

The cost for the system is $17500. Including the 30% federal tax credit the system is paid off with 4 years energy savings.

Any pictures of the manifold system?

I guess that I didn't get one, sorry.....

Great stuff Dwight. Yet another benefit of having a pond. Four year payback - that is fantastic!

If you get that Death Star Geo Transfer Unit built, you could suck heat and cool from peoples ponds without them even knowing!

It's a good system, except for the external thermal exhaust port, about 2 meters across (just smaller than a wamp rat).

It's on the list. Right now the GSA budget is stretched a little thin. We're trying to design a system to remotely implant tracking devices in "persons of interest." Long distance accuracy of the of the implant device is not great right now. On the upside though we know where TomG's next door neighbor is all times though.

Wamp rat? Naaa, never mind. I'm thinking that what ever that is I don't want to know.

Looks great Dwight!

One question I have. Is'nt that trench going to settle without a small mound over the dug area to allow for recompaction??


BTW, now that you'll have a warm winter haven, tilapia will make Darlene (x at least 6) pop that 10 pound hurdle quicker so you can collect from Cecil!

Wamp rats LOVE GSF and pantyhose!

Methinks Theo left off an "S" in front of Wamps.

No, but I did mispell it: Womp Rat

And there were swamp womp rats!

It is mounded to compensate for settling. My photography just doesn't show it.

I'm an idiot, perhaps Dwight you can break it down for me as to how the Geo project works as compared to a standard heating and cooling system? It seems so interesting to me...

I asked that same question and got told to look it up on the internet. Here is a brief simple explanation:

http://www.stantonhomes.com/Docs/Geothermal_Systems_Information_Raleigh_Custom_Homes_Builder.pdf

In simple terms the geothermal system works like a window air conditioner. If the air conditioner is installed normally it pumps cold air into the house. If it is installed backwards it pumps heat into the house.

The geo unit pumps heat from the earth rather than from the air. In ac mode the geo unit pumps heat into the earth and in heat mode the geo unit pumps heat out of the earth.

May I ask approx cost of a project like this?

Our heating system is radiant and it is terrible, and our AC system is on its last leg, so we are fixing to upgrade in a couple of years anyways. We are about 100 ft from the pond.

Dwight, your system is very similiar with what we did (see other geo threads). Costs on target. I finally got a yearly anaylsis done and my savings (even with some initial problems that ocured) is running $3,800 a year so I still hope to recoup costs in 5 years.

Things that may help you along the way, is I ended up having them come back and put more 'spacers' between coils, my coils were more compact whereas yours are spaced maybe twice the length. They also added an extra coil, no costs, which is just a bonus for me. I am going with a new thermostat that tells me when my 'heat strips' do kick in. After much learning and watching my electric bills, which I did have an extremely high month (but come to find out so did everyone else in the area with geo). I have worked thru the issue and bottomline, is my total year came in below target so I am quite pleased. My geo continues to outperform my expectations. It is comfortable, barely notice it, I don't have the nose bleeds like bofore. I don't miss the high propane bills. Worthy investment. Keep us posted on your progress.

Our Geothermal system has now been in operation for about 24 hours. I have included some photos with a brief explanation.

The new thermostat controls three heating stages and the two cooling stages. The two stage compressor provides heating and cooling stages one and two and the electric heat module provides the third heat stage in extremely cold weather. The Geo unit blower runs at low rpm (740) when no heat or cooling is required. This provides continuous circulation through out the house. The results are clean air and stable room to room climate control.


This is the entry point for the pond loop.


There is a significant amount of work involved to plumb from the entry point to the Geo unit.






I added two 220v circuits, a 50 amp for the Geo unit and a 60 amp for the auxiliary electric heat. Wire for both is 6 gauge copper.


The installed Geo unit.


Plenum air temperature monitor. At the time the photo was taken the unit was in circulation only mode.


Water pumps.


View of the back of the pumps, the fill tube and level indicator, and the flow meter.


Close up of the level gauge.


Close up of the fill opening/plug and the flow meter. The water/antifreeze solution is circulating at 11 GPM.


Now it follows that the high efficiency condensing furnace removed from the house needs to be installed in the shop. Again proving the adage that a man’s work is never done.

The electric company is coming out tomorrow to install the submetering so we get the cheapest rate for heating and cooling. 4.5 cents per KW.

The old house furnance is now installed as the new shop furnace. It is never too early to be prepared when you live in Minnesota!

I sense the ductwork was somewhat simpler with this installation.

Yes, it was a lot easier. It was recycled from the old shop furnace. It is ugly, but it works.

We had a problem with our Geo Unit not putting out enough heat to keep the house at 70 degrees last night (Low outside temp in the vicinity of -0 F with 35-45 mph winds). The inside temperature went down to 67 F and then hovered there with the unit running all night.

It is a three stage unit (2 compressor stages and the 3rd stage is auxiliary electric resistance). It appeared to me that only the first stage was running so I took some plenum and loop in-out temperature readings and called the heating company about it. Since the loop in and out temperatures were only 3.4 degrees apart and the heat plenum temperature was 82.4 degrees they too thought only the first stage was running.

Their tech came out and determined that the thermostat was setup for a 2 stage system not 3 stage. So, we have been running on the first stage through the cooling season and (until today) the heating season with no apparent problems.

It was an easy programming change and we are now loaded for whatever nature hangs on us.

I turned the circuit breaker off on the 3rd stage since I really prefer to pay the electric company as little as possible.

Tonight we are headed to -15 F with some wind so the 2nd stage will get to finally do its job. The Tech and I concur that we may never need the third stage unless something extreme occurs, like -30 F and 50mph winds. I am fine with that. Service call charge $0.00. I am fine with that too.

Thermostats just keep getting more complicated.