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[skorpyd]

I have had an idea kicking around in my head about using the pumps and heat exchanger I will be putting in my furnace plenum from my in process homemade owb.

The idea is to bury separate from my insulated pex lines for heating, some uninsulated pex about 48" or more down in the ground, allowing the ground to cool the piping.   Then during summer, hook up to the lines running to the heat exchanger in the furnace and running the fan to force the cooler air into the house.

Looking for ideas on what's right or wrong with this idea.

[Drivebymashing]

Ive actually thought about that too.I think it would work .But i decied to leave my boiler on all year to heat my water and hottub.

[netwerx-r-us]

Im looking at doing this for my greenhouse , not using my boiler but my pump and lines , I have a spring about 75 ft from my boiler , water stays at about 55 , going to use it in my greenhouse for cooling using my heat exchanger fan and thermostat,

I also thought about using it on the house but everyone Ive talked to with hvac experience says I will have a huge moisture issue dumping all that moisture in the house , here's his exact words , engineer on HVAC

"You can cool your house some with the spring water but a typical AC unit has to have the evaporator coil reach approximately 37 degrees to pull the humidity out of your house. That’s why when you see your AC unit dispersing water, that’s humidity in the house. I was an engineer in OKC and we made geothermal units. To achieve the desired temperature you will need a chiller to pull the water temps. on down".

[Scott7m]

Won't work....   This was interesting to me, I've answered it on the forum many times, but can't remember what the killer really was according to my research. 

It had something to do with humidity  in the home, sweating,  and two different forms of air in the home. 

I wasn't thinking about using the boiler, I was simply talking burying 500 ft of line in the yard and circulating water through it, but your house would be soaked inside

[RSI]

If done right it should work. 55 degrees might not be cold enough to condense water on a finned heat exchanger but it is on a pipe. If I were to ever do it I would put a fairly large coil of copper pipe in the return side of the furnace with a drain pan for the water and then run from there to the heat exchanger in the plenum. If enough pipe is used in the return it will raise the temperature of the water going into the heat exchanger enough so there is no condensation to deal with there.

[Scott7m]

If done right it should work. 55 degrees might not be cold enough to condense water on a finned heat exchanger but it is on a pipe. If I were to ever do it I would put a fairly large coil of copper pipe in the return side of the furnace with a drain pan for the water and then run from there to the heat exchanger in the plenum. If enough pipe is used in the return it will raise the temperature of the water going into the heat exchanger enough so there is no condensation to deal with there.

There are some articles online of someone who tried it, can't find them one tho.  With doing what your saying how would you get the humidity out of the air?

[RSI]

The coil in the return would take it out. I am thinking of a coil similar to what is in a dehumidifier but much larger.

Many years ago my brother put a coil of pipe in the furnace in the house he was in and just hooked it to the well water and then ran it outside onto the ground. He had water running off the pipe in the furnace like crazy and it cooled the house fairly well. It was a small house though and probably wasn't too cheap running the well pump.

[Scott7m]

I'm just not sure how you could get it to condense that much.  The article I read said the whole house felt damp all the time.  I don't know hmm

[RSI]

I don't know either but at least it would condense. The fins on the heat exchanger would never get cold enough to condense properly unless it was colder but a pipe should be better.

If it doesn't work, what about using the A/C to dry the house and then just the water to keep the temp down? I would think it would be able to at least cut down on A/C cost.

[Scott7m]

Maybe so.....  It would be a big help

That's shy I'm looking into solar, I have the winter bills under control but $300/mo for ac is crazy.....

[skorpyd]

Thanks for the replys,

I've been away for a few days actually working on the boiler build.   

I figured it probably wouldn't work or it would be being done as a fairly common practice.  As it is the humidity that causes the most discomfort in hot weather it now makes more sense to me.   I need to learn more about how cooling actually works.

[gandrimp]

It can be done, but Im not sure how. Heres a company that sells waste oil furnaces, they also sell waste oil a/c units.  http://www.econoheat.com/waste-oil-equipment/air-conditioners/  .I have one of their heaters and I dont recommend the company, but just showing that there is a unit using fire to make a/c.