Geothermal on the cheap

I have a very well insulated shop, 36' x 48' x 18'.

I am wondering about trenching in a loop of cheap black plastic water line, adding a small circulating pump and a salvage truck radiator rigged with a fan.

How deep do you have to go for the constant 50&deg temperature ?

Located near St. Loius, MO.

Would it work, or is this idea craziness ?

You will find that you can not get enough BTU exchange with just a single loop of pipe. Actually several loops will usually not do it. Also 50 degree air will not feel warm when a fan blows it around. I would bet that you could not even keep it above freezing.

The depth to get to 50 degrees is around 5-6 feet most of the time. Soil type and water tables can make that vari a little. Sandy soils will be deeper and high water table may be shallower.

I agree with JD, A heat pump works by shifting the temperature points. You will need water much colder than 50 degrees to get air down near there.

The bigger the temperature difference the faster the heat exchanges. So trying to pull heat or cool out with a fan won't work very well. You need a heat pump to extract the energy.

We put geothermal in our house 4 years ago and it works great.It cost 9000 and we got a 2000 dollar tax deduction.I don't know what makes geo so expensive.I bet there isn't a 1000 dollars worth of stuff there wholesale.The company that makes the scroll pumps is near me.The 3.5 ton until sells wholesale for around 300 bucks.

I figured it may not work too well.

I was mainly looking to cool in the summer.

I have a large (2' dia. by 3' wide) squirrel cage blower that would really move some air through that radiator.

But I guess moving 85&deg shop air through a 50&deg radiator still wouldn't remove that much heat from the air.

I suspect the reason they sell them for 9000 is because "they can".

I agree it is sad they prefer to raise prices just because they can, instead of selling them for what they are actually worth.

I have some soybeans that I'd take a hundred bucks a bushel for-anybody interested ?

You might get the chance this fall to sell the beans for that.

Depending on your water table you may find it easier to hammer two wells. Use one well to supply the cool water to the radiator inside your shop and the other well to the return warm water to the ground. If you have another use for the water, make up water for a pond etc. the second well would not be required.

Assuming the water enters your radiator At 50 degrees F and exits at 60 degrees F, each gallon of water can supply 83 Btu of cooling. Also, lets assume the shop air enters the radiator at 90 degrees F and exits at 70 degrees F. The 83 Btu from the water can cool 227 cubic feet of air the 20 degrees (90 to 70). NOTE, this is for dry air, humidity will reduce the performance same as for an air conditioner.

A 36' x 48' x 18' shop encloses 31,104 cubic feet of air. Using a 1 GPM pump will supply 227 cubic feet of cool air per minute and require 137 minutes for one air exchange. A 10 GPM pump could supply enough cooling for one air exchange each 13.7 minutes.

Yes it is possible....it can make a significant difference if sized corrrectly.

In Missouri the best you can hope for is about 55 degrees and that is about 8-10 feet deep. Reason for that deep is so as to insulate for the 18-24 inches of frost line so as to keep a constant temp. Spent more then one night in a cave and took temp readings when there and if you where in deep enough you had a constant 55. Other thing to think about is having to have a low GPM pump or you do not get a good exchange of cool to hot air/water

I have thought of using the well but the water would just get hot in 30 min. You have to have all of the tubing for hot and cold dispensation.

If you want it for cooling then dog down to 5 to 7 ft. And put in a pipe that will carry enough air to cool the room, no fan just let it rise on its own.
There are lots of good book on this subject get a couple and the desire what you want to do.for cooling only you will need a 1 to 2 ft. Dia. Pipe. The water system is for heating cooling.
My system is easy and cheap and works great.
Walt

(quoted from post at 19:24:12 07/13/12)
Depending on your water table you may find it easier to hammer two wells. Use one well to supply the cool water to the radiator inside your shop and the other well to the return warm water to the ground. If you have another use for the water, make up water for a pond etc. the second well would not be required.

Assuming the water enters your radiator At 50 degrees F and exits at 60 degrees F, each gallon of water can supply 83 Btu of cooling. Also, lets assume the shop air enters the radiator at 90 degrees F and exits at 70 degrees F. The 83 Btu from the water can cool 227 cubic feet of air the 20 degrees (90 to 70). NOTE, this is for dry air, humidity will reduce the performance same as for an air conditioner.

A 36' x 48' x 18' shop encloses 31,104 cubic feet of air. Using a 1 GPM pump will supply 227 cubic feet of cool air per minute and require 137 minutes for one air exchange. A 10 GPM pump could supply enough cooling for one air exchange each 13.7 minutes.

Yes it is possible....it can make a significant difference if sized corrrectly.

Click to expand...

gotta luv it!!! good job Ken! We need people like you!

I see it with medical service providers. They look at insurance as your "discount" and set prices accordingly. I was told when negotiating with a famous cancer hospital in Houston, TX about my remaining balance after all insurance payments that they cannot give more discount, not even cash discounts, especially since I already got one when my insurance paid there share. I almost flipped a dipper...!!!! Sooooooo, they probably used to sell it for 7000, but decided to up it to 9000 because of the tax credit...!!?

Why would the well water get warm?
What is there for a well or wells on the property?
I almost went with a well water 20X20 Hx in the furnace return air duct this year. And dump the used warm water either out to the orchard irrigation or to the swan pond. The birds are getting hissy about the dropping water level in the pond area.
There are places in the creek bed where it's as cracked and dried as my lawn.

The big expense is the wells. Most systems when properly designed will require 3 to 4 wells drilled and then they have to be backfilled with bentonite ($$$). If DNR finds out with out permits then big fines. best is a ground source heat pump with built in a/c. no outside compressor, all heat is returned to the well and the side effect is you can get free hot water. Friend has a 2500 sf house and his electric bill runs $80. per month all year long. He has had this since 1992 so the system has paid for itself after 10 years.
2" pipe with return down each well about 200' each.

Eric, Here is the theory behind BTU's. One BTU is the energy to change the temperature of one pound of water 1 degree. So let's say you have 50 degree water and you lower it's temp to 40 degrees, that's 10 BTU's / pound of water. On the other hand if you have 50 degree water and you warm it up to 60 degrees, then you have 10 BTU's of cooling. So it's really a simple math problem, how much heat exchange do you get in both your pipe and radiator and the volume of water you are pumping. 8.34 pounds/ gallon/ Your major problem will be freezing up in the winter.

In 2000 my A/C compressor went bad. System was 30 years old. I needed cooling and it was in the middle of August and I had to go back to work. It took about 10 days before a new A/C could be installed. I pulled the old A coil out, and installed a used 3 ton A coil. Rigged up garden hoses and passed the water through the cap tubes like it was freon and ran the fan constantly. It kept the house comfortable enough for my wife, who at the time was on oxygen 24/7. The down side to using 55 degree well water is it's not cold enough to remove moisture like an A/C.

This idea isn't a new one, Carrier did it in about 1905. I think Jefferson or Jackson had a house by Nashville, Tn, that was cooled with spring water running through pipes and slaves operated the bellows to move the air.

I've always wanted to do this again, using large condensor and evaporator coils from commercial units, however the price of scrap is too much.

You are going to needs tons of water to heat or cool your building. Plan big. Let us know how it works. It may be better to use a well and dump the water on your lawn, field or garden.

A ton of water per hour, 2000 pounds, change the temp 10 degrees, and you have 20,000 BTU's/hour. That's not much for the size of building you have. Depending on your heat exchange rate, you may need 2 or 3 ton per hour.

George

Eric,
In theory your idea is right, but I don't think you'll get enough cooling for the volume of your shop.

Another poster mentioned digging long tubes underground and piping those into the shop. Again, you'er gonna need a whole lot of 1 or 2 foot drain pipe buried. In the UP of Michigan, its not uncommon to see air being drawn out of some of the old mine shafts. Again a whole lot more volume in those mine shafts than a couple hundred feet of pipe 6 foot deep in your yard.

I have a 6 ton geo in my house and slowly planning a 3 or 4 ton for my shop. I have the benefit of an 18 foot deep pond that will be used for the shop geo.

In Michigan, now I think it is illegal to return the water to the ground if you run vertical wells, they have to be closed loop.

Rick

THANKS to all who replied.

You have really got me thinking now.

" have a large (2' dia. by 3' wide) squirrel cage blower that would really move some air through that radiator"


rig up a fine mist sprayer to your fan, feed it well water and let it blow into your shop. works better the lower the humidity. local garage does that here in Central Ohio

good luck

After thought. My well produces 12 gallons/minute and uses 1200 watts. A fan would use 800-1000 watts. So say you are using 2000 w. A new high efficiency A/C having a SEER of 20 and uses 2000 watts and produce 40,000 BTU's.

If you have to buy all your Geo parts, pay for backhoe work, cost to operate, it may be cheaper in the long run to buy an A/C.

That is a closed loop well system. We were thinking open loop water wells.

Heat pumps have been promoted via gov't grants around here until recently. Until politicians learned there were cheaper ways to purchase more votes.
For even the urban folk with postage stamp sized lots were going geothermal. Problem is along the north shore of Lake Erie and north e Lake Ontario. The drillers hit natural gas deposits without warning.........almost a huge poof.
Deep drilling is difficult of impossible in some areas now. Too many recent memories of Sunrise Propane blowing up a subdivision.