[QUOTE=IndyIan;28580]diesel_john,
Do you heat with your pond system as well in the winter? How's the efficiency then?
The COP (heat) is about 4. You get 4 kw of heat for every 1 kw the pumps use. Plus the household water heating is off the desuperheater which is much more efficient than an electric water heater. A bigger hot water tank for storage is helpful.
Mine is in the ordering parts stage. I won't be complete till end of summer.
I just went to a meeting last week.
General rules of thumb (but your mileage could vary greatly) on the loops. I only considered close loops because of scaling problems in open loop. (water quality?)
vertical wells: 200'-300' per ton, 150' deep. 10' apart. $1000-3000 per well.
horizontal trench: 300'-600' per ton, 8' deep. up to $4000 per ton
pond minimum 1/2 acre, 8' deep. 300'+ per ton. If your going to let the tubes get covered with silt then more tubing is required. Slinky lay out more tubing. Wholesale on the tubing is about a $1/ft. for 3/4". Fittings are special heat fuseable plastic. No metal parts in the ground.
300' generally max. loop length.
What i am curious about is how much heat will the pond store into Fall and how much cooler will the pond be next spring into the AC season?
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