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01-05-09, 07:40 PM | #1 |
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Has anyone ever done a DIY geothermal A/C?
My Bio-Diesel Garage is going to be in need of A/C soon. I have a dehumidifier in there now; but when things warm up I'd rather just cool and dry it than just dry it.
I would like to do everything I can to keep the project as green as posable; but the budget is slim (especially with fuel prices low). So here's the Idea Take an old window unit build a water tight box around the condenser, put a submersible pump at the bottom on one side and the return on the other. I could also silicone a series of walls to both sides of the condenser forcing the water to flow in an S shape many times . . . I'm thinking about using typical horizontal in ground loop using coils of tubing. My garage is in a 3.5 acre field so space is absolutely no issue. Looking at 5,000 btu Window unit $ Free (already have) Fountain pump $30 water tight box $30 Tubing $200 ?? EDIT: Just found 100' of 3/4" Polyethylene tube for $17 at lowes so 500' is $50http://www.lowes.com/lowes/lkn?action=productDetail&productId=24166-000000150-24166&lpage=none Excavator rental $200 ?? So under $400 for a Geothermal cooler. Payback would still be pretty long but at that price point I'm willing to absorb it. Any Ideas? Comments? Modifications? Reasons it won't work? Please no "Just buy a commercially produced system and pay someone to install it" that is way out of the price range I'm looking at for this project. Last edited by dremd; 01-05-09 at 08:32 PM.. |
01-11-09, 07:21 PM | #2 |
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Damn; I was hoping for some discussion.
I did have a good Idea for testing; 55 gallon barrels of water to replace the ground loop (just for testing/ short term). |
01-12-09, 01:20 AM | #3 |
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If you have a stream flowing past, or a beach, or the aquifer has flow through it, you might not need a pump, as the water comes to you courtesy of Mother Nature.
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01-12-09, 07:44 AM | #4 | |
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Going by the post on the other thread I think I'm going to give it a go with barrel testing. I just acquired another free window unit of questionable quality going to try that one out first. |
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01-12-09, 09:59 AM | #5 | |
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Then you're in excellent shape: Rent one of those 2-stroke augers to drill down to the ground water, to a depth ~10' below the water table, making a couple of holes laterally separated by ~50' to ~100'. Or, Google for "driven well point," available at home improvement centers and hardware stores for ~$50. Pump water up out of one hole, pass it through the heat exchanger, then drain back down the second hole. If your'e in Lousisana, soil is probably pretty sandy and wet, with ground temp ~60ish, which is perfect. This will provide all the heat and cooling you'll ever need, assuming your place has decent insulation. For the barrel test, I suggest immersing the heat exchanger at the bottom of the barrel, making sure that there is adequate space around it for the water to circulate by convective heat transfer (Google for it), as works with an old fashioned room radiator. Once the barrel test works out, you could simply bury the barrel in the yard, below frost line, then route the tubes to/from the wells into/out of the barrel. The barrel itself with also radiate or absorb heat through its skin into/out of the surrounding soil, effectively increasing the size of the heat exchanger. Since water is ~800 times denser than air, and since the ground water at your place is probably just about perfect temp, you oughta have lots of free heat and cooling. |
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01-12-09, 09:45 PM | #6 | |||||||
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Where my camp is (15 miles east) is blackjack. My well water temp is 63~68 depending on season. Quote:
Garage is 200 square feet, asphalt roof, metal walls concrete slab floor. I don't want to get ahead of myself but the house with the same setup would be killer. Quote:
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I'm getting excited |
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01-13-09, 01:28 AM | #7 | |
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The underground container should be metal (preferably aluminum), which conducts heat vastly better than wood or plastic. Concrete is pretty good, too. The container and pipes are, in effect, extensions of the heat exchanger, so you'd want to insulate that portion carrying the heated or cooled product to the house. Your 68 degree ground water temp is excellent for heating, could be better for cooling. Plant deciduous trees to provide shade in summer, yet allow sunlight to the house in winter. In addition to shade, a tree is a wonderful air conditioner, as it draws hundreds of gallons of water from the soil, then evaporates it into the surrounding micro-climate, dissipating heat via latent heat of evaporation, just as your skin does with perspiration. That's the principle behind those atrium fountains the ancient Romans and Moors used--fountain sprinkle evaporates and cools the surrounding air. The Chinese have a tree that makes small berries which are excellent fuel, being mostly oil, that could be burned in winter in a wood pellet stove. Your county ag extension agent could help with particulars. Paint the building white, as white reflects sunlight and infared/ultraviolet energy much better than dark colors. A light-colored roof is a major advantage in the Sun Belt. Home improvement stores also sell perforated reflective foil to put in attics or under shingles, which reflects energy away from the interior (or back into it). Cheap to install during original construction, but a pita after. Best to keep the building from getting too hot in the first place, rather than then trying to expel heat from the building after the heat gets in. Indigenous or "cracker" architecture in the South was developed from keen insight and experience long before the days of the air conditioner, with lots of good passive methods to keep cooler, such as higher ceilings, attic fans, white paint, etc.. In colonial Williamsburg VA, they ate ice cream in August, a century before electricity or air conditioning existed, by preserving winter ice in an ice house, buried below ground and insulated with straw. Seems to me, such ancient technology could be applied today. Last edited by Otto; 01-13-09 at 01:34 AM.. |
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01-13-09, 09:18 AM | #8 |
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If your primary purpose is to dry out water, why not run a dehumidifier instead of cooling down the entire area? I'm sure the dehumidifier could be augmented with a heat pump as well.
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01-13-09, 09:25 AM | #9 | |
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Now that I'm thinking about it I realy don't need heat but for 5-10 nights per year just to prevent freezing. |
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01-19-09, 03:08 PM | #10 |
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sounds like I may be able to get in on a fraction of a 1 week trencher rental in the future; not perfect; but I may go for it instead of the excavator.
Edit: Looks like a few window units are available with heat pumps; but most are just resistive heat. Smallest Heat pump I saw was 11,800 btu. Which is about double what I want. Looks like I'll just do resistive heat (space heater) for the few nights that I need it. If I needed 10,000 + BTU I'd jump on it though. Last edited by dremd; 01-19-09 at 03:18 PM.. |
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