Pond Boss Forums INTRO Questions & Observations Geothermal Heat Pump

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.