We live in a solar home that we built last year. One of the ideas we have is to circulate water from a spring-fed pond (very cold) into a couple of old window air conditioners (sans compressors) and let this be our air conditioning. It is, I believe, a form of Geothermal cooling. Has anyone had any experience with this sort of thing? I plan on using a hydronic heating pump to circulate the liquid (antifreeze?) and just running a closed loop of buried plastic pipe. any ideas or information would be greatly appreciated.

-- Wayne in Kentucky (wallen328@aol.com), February 09, 2001

Answers

Well you lost me. At first i thought you were just going to make a water cooler. just running water over a fiber mat that has air being drawn throught it. Mom used one when i was a kid, its sitting out on the farm rotting now. Not sure what you are doing with the with the plastic pipe. are you running the line in the water then to your house to cool your house? just wondering, Mike

-- MikeinKS (mhonk@oz-online.net), February 10, 2001.

This has me thinking.... How about a series of small diameter metal pipes. That should conduct the cold into the room. Condensation could be a problem.

What about those heater systems where you have a wood burning system outside and a water system to carry the heat into the house? It ssems that that could be modified to take in the cold spring water....

-- Paul Wheaton (paul@javaranch.com), February 10, 2001.

Wayne in Tucky! My $2. worth of advice! About the easiest and most cost effective [cheapo gizmo] would be to make a pickup in the pond above the bottom, draw the water through a filter ]different ways to do that] and pump it into the house. Using an old radiator or A-coil, circulate the water thorugh it with a fan/blower behind. You'll need to have a drain tray under the coil because condensation will runn off the coils and will need to be drained off. Simplified way of say'n it but it's feasable, pratical and it works. By buring pipes deep into the soil the same thing can be accomplished without using the pond water. Drawback to that is you'll need lots more feet of buried pipe without the cool of the pond water. With more info on what you have I'll help you design a system that will work and not cost an arm and leg to build or operate. Matt.24:44

-- hoot, tightwad gibson (hoot@pcinetwork.com), February 10, 2001.

Wayne This should work, you will need bigger cooling coils then when using freon. I would not use antifreeze because it is toxic and a leak in the system could contaminate the pond..........JAY

-- JAY (JAY@townsqr.com), February 10, 2001.

Thanks for the inputs. I was gonna use the finned heat exchange areas of the old air conditioners with fan behind to transfer the cold of the water into the house. I even toyed with using a couple of old auto radiators with fans behind, or some modern fin-type radiators at floor level without fans. I believe there is an RV-type antifreeze that is used for water systems that is nontoxic, and intend to use a continuous run of high-pressure plastic pipe to form a grid on the bottom of the pond to lessen the chance of a leak. As my electricity is solar, I need to devise a system that is as energy-efficient as possible, so any further comments or ideas are most welcome. Wayne in Kentucky

-- Wayne in Kentucky (wallen328@aol.com), February 11, 2001.

I think Hoot has the right idea about having an open loop. The suction side of the pipe is screened at the inlet to keep the junk out then a circulation pump is used. You'd need some kinda drain-back in place tho so the system would automatically drain when the pumps not running.

As to the fin tubing/coils in the house I tend to agree with Jay. Coils that are specifically designed for refrigerant are substantially smaller than those that are designed for water. I don't KNOW if that would create a problem or not but it would create a flow restriction if you're pumping alot of water.

-- john leake (natlivent@pcpros.net), February 16, 2001.

This system will work,but there is a little more to it than meet the eye.1)All line from the water source to the home has to be at least 4 foot under ground.The temperature at that level will be in the 55 degree level.2)antifreeze solution will conduct and transfer more ambient heat than straight water.Now comes the trickey part.3)You have to determine heat(cooling) load you are working with.Once you know this you can either guess the rest or do like i am trying to do ,is finding figures on 4)how much heat (cool) can be tranfered thru the conductor (pipe) per foot,diameter and gallon of waterflow.If you can find this figure out this will give you the amount of feet of pipe for the pond or water source.I have been trying to get mfg. to give me some ideas on this figure but have had no luck. I believe a plastic tubing such as Wasbro glass fiber tubing would work well because it is tough,non deteriating and flexible.I have used it as an expirement system an it seems to fit the bill.Now comes the good part, 5)how big of condensor (heat transfer unit) do i need? These figures to me have been quite hard to find if not impossible to come up with by the webb.Any help would appreciated. Now we have to match air flow over the cooling coils to put the lower tempture air into the duct system. I would recommend to use the same blower c.f.m. as your heating system. DO NOT try to force the new system air thu your current h.v.a.c. system.You want to run a parallel system an isolate the present system(block off so air flow will not recirculate thru the heat exchanger and the present condensate coils).You will have to have a condensate drip pan under the new coil assembly which are available at your h.v.a.c. supplier. It will work but if it is not sized correctly it will be lots of work for nothing.I use a outside furnace in this matter an it does a find job an really cut my fuel bill to nothing. You don't have to use water for the heat transfer medium,the soil will work just as good.

-- Martin in mo. (4statehomepro@tiadon.com), April 28, 2001.