Pretty Cheap House Cooling?

[Coyote X]

So a year or two ago I tried something simple to see if it worked, I put a sump pump out in the creek in my back yard. Hooked a water hose to it and ran it through a window in my house that attached to an old car radiator. Then ran the other end of the radiator back out to the creek. With a normal box fan on the radiator it could cool my house down almost as good as the window a/c I have. I used it for a week or two but ran over the hose with a lawnmower and never bothered to fix it.

So I am thinking now that I acquired a new toy

I am wanting to redo this system but make it a bit more permanent and better working. The plan is to dig a really big hole in the yard at least 6ft deep so it is below the water table in my yard and put a large tank of some sort in the ground. I am thinking of a 500 gallon tank. I can fill the tank with water and it will pretty much stay at ground temp of 55 degrees F. From there I can pump the water through a car radiator/fan setup in the house somewhere and cool the house with very little electric required.

a 3/4" pipe should be more than big enough for the amount of flow I figure and a small pump is all that will be needed since there will be no lifting of the water, just pumping it closed loop. All of that is just a wild guess but it seems like it should work. If it does work it would be really cheap to keep the house nice and cool all summer. The house is 25'x40' with 7ft high ceilings and no insulation at all, just some blow in insulation added to the attic. If anyone has any experience with something like this and would know of what size tank and flow I actually need let me know.

I could insulate the house but it costs me like $300 a winter to heat it so it really isn't worth the trouble. If this works I have some strange ideas to try for solar heating

[extragoode]

Sounds like basically a DIY ground source heat pump on the cheap. Sounds reasonable enough. Is your tank going to have an open bottom to basically use like a well? Otherwise, I would worry that it might actually insulate the return from the ground too much.

[Coyote X]

I was thinking of instead of using it like a well just put a sealed tank below the water line so it was always wet on the outside. It seems like it should be able to conduct enough heat through it to keep cool. I could be wrong though

The way the temperatures are here normally if I want to run a/c I normally turn it on at 12-1 and run it till about 5 or 6. There are enough trees around the house to keep it tolerable without a/c and just open windows with fans in them. I haven't turned on the a/c this year actually. Mainly because I haven't been in the house during the day so the fans keep it good enough. I figure 4 20" box fans are probably taking the same amount of power as one box fan and a small water pump but the house would be much cooler with the ground based setup.

[extragoode]

If you're talking about a metal tank, you're probably right, but I assumed you were planning on a plastic tank. It might be a good idea to do some testing before you go to all the trouble of installing this big tank in the ground. I'm just afraid the amount of heat removed from the house is going to be more the the ground can remove from your water and then your efficiency goes down the tubes. In commercial systems they use the compressor to increase the temperature differential between the medium (water in your case, but they usually us some sort of antifreeze) and the ground, but that's so they don't have to use a reservoir like you're doing.

Good luck.

[MazdaMatt]

Ha... i have a car rad in the back of my car right now that I was going to run cold water through to cool my living room. It seems like a good plan. You say the creek was feeding your system well? What if you just buried an open-topped box in the creek with 3-4 parallel car rads and make it a closed system?? If it works well, add some antifreeze or "Water Wetter" to the system to improve its heat transfer ability. This is brilliant, by the way, kudos.

[rjacob]

We have a Sanyo Tri-Zone A/C unit. Does a very good job. Our cooling costs are cheap. It's our heating costs that are up there. Our winter power bills are usually about 4-6 times our summer power bills.

But I do like your creek water cooling system.

[jamesqf]

I'd re-think the insulation. Since I got the attic insulated, I can open windows at night and cool the place down, then close them in the morning, and even on a 100 degree day it will stay below 70 until 5 or so. Of course this is in northern Nevada, where it usually drops below 60 at night even on the hottest days. May not do as well in more humid areas. But even so, your ground-source A/C wouldn't have to work nearly as hard.

[Coyote X]

The creek is not very consistent. Right now it is at best an inch deep and a foot or two wide. Sometimes after a heavy rain it is 5ft deep and a lot of silt and mud in it. So anything I put in the creek will either get washed away over time or be buried in silt from the strip mines. The system I put together before was I think a 1/4hp sump pump running to a good size garden hose and the exit from the radiator('75 dodge polara) was also the same size garden hose running back down to the creek to keep the pump from having to lift the water as high. I figure the pump was putting out a lot more flow than it needed but it was just stuff I already had so it got put to use. If someone had a more consistent stream near their house a coil of copper pipe or old radiator put in the stream could probably be used to transfer the heat using a closed system and be pretty reliable. I did it mainly just to see if it would actually work, I was bored and had nothing better to do than mess around and build things. This summer I am just looking for excuses to play with the tractor

I asked a few people today and one guy says he could get me a used 10,000 gallon tank for free if I come get it. No idea how I would haul it in a Metro and the little Kubota tractor I have would take 6 months to dig a hole that size. But I did manage to find a potentially endless supply of 55 gallon barrels for free So now the plan is dig a ditch wide enough for the barrels and keep them about 3ft apart and run the water through them in series. I have no idea how many barrels I need but I might get a few of them and bury them to run an experiment. I could probably dig a hole and put 2 barrels in the ground and hook up a working system in a day without a lot of effort. The two barrels would give me a better idea of how much heat each one could handle so I know how many actually need to be used. Then I could get that many plus a few extras and hook up a more permanent system.

I don't actually think this would save me much money in the short term though. My electric bills are pretty much always $35 a month since I haven't used a/c this year, ~$100 with heavy a/c use. I am just not in the house during the day to care how hot it is in here. Winter my gas bills max out at around $90 so really it doesn't cost much to just keep doing what I am doing now.

[dremd]

Originally Posted by Coyote X

But I did manage to find a potentially endless supply of 55 gallon barrels for free So now the plan is dig

NOW there is a good heat transfer.

If you got a heat pump window unit and encased the condenser (outside cooling fins) in water pumped through these barrels then you would have an excellent heater as well as a very cool/ efficient A/C. Just wire the pump on a contact or with the compressor. if the system is closed you can get away with a very small pump.

[Arminius]

Pretty impressive, CoyoteX. I've always wondered if I could do that with my well.

Are you having any issues with condensed water?