I was thinking about a diy geothermal heating and cooling but would like it ultra cheap. Like rent ditch witch and just using pex pipe and a some pvc and truck radiator and a box fan and just a 110volt pump. But wondering if would work and if any one has done it before.
Cheap DIY Geothermal Heating and Cooling
- Thread starter chevyc10
- Start date
inphx
Well-known member
interested in the calculations as well. Doing some new build and can put pex under 5000sqft slab - but dont need it to heat the floor, instead wondering how it may be used to cool with a radiator or http://www.pexuniverse.com/brazetek-24x24-water-to-air-finned-coil-heat-exchanger. I guess if i knew estimated temp at pex buried level x #feet plus some capacity of the exchange radiator there may be some prediction of feasability.
snorky18
Well-known member
Someone, somewhere, has probably done it, but there's a lot more that can go wrong than right, and it would probably not be ultra cheap. You'd want to use PE pipe, not PEX. Design has several rules of thumb, but there's a lot more than two thumbs there. Oversize the pump, your electrictiy consumption skyrockets. Undersize it, and you won't be effective. Same goes for loop sizing. Also, groundwater table plays a huge part in thermal conductivity, and seasonal variations can be considerable.
I'm an engineer, who does pretty much everything myself (concept>design>build), and I considered DIY geothermal for our HVAC unit. I designed it, priced it, would have done all of the installation myself, and had a engineer/contractor bid it to check my work and price, but in the end it was too expensive and too many variables.
Ymmv.
If Farmer John pops in and says yes, he had a spare radiator and did it for super cheap, and it works great, I'll say great for him, and I'll be curious as to what he did specifically.
But IMHO, I wouldn't recommend it, you may end up wasting some pex, pvc, a truck radiator, ditch witch rental, and time.
I'm an engineer, who does pretty much everything myself (concept>design>build), and I considered DIY geothermal for our HVAC unit. I designed it, priced it, would have done all of the installation myself, and had a engineer/contractor bid it to check my work and price, but in the end it was too expensive and too many variables.
Ymmv.
If Farmer John pops in and says yes, he had a spare radiator and did it for super cheap, and it works great, I'll say great for him, and I'll be curious as to what he did specifically.
But IMHO, I wouldn't recommend it, you may end up wasting some pex, pvc, a truck radiator, ditch witch rental, and time.
Ground temp at about eight feet down stays about 65 all year, without the heatpump portion of the setup you likely won't get any dehumidification and if it is able to cool the room down it would be clammy. It takes a lot of pipe in the ground too, most that I've seen are deeper then 10 ft, I don't know how deep a ditch witch can go but it would probably have to be a really big one to go that deep.
HoosierBuddy
Well-known member
Had a guy up the road from me try that. He cut a gas line making his first loop. I think that cost him enough he could have cooled the house a few years for the same money.
I guess my take on it, as an engineer like snorkey, but NOT someone who has tried to design this would be: If it would work, that's what we'd all be using. I mean, I'm a good engineer, but there's better ones out there. If this was viable, someone would hold the patent, someone else would have already offshored the production to China, the Chinese would have stolen the idea from that person, reverse engineered it, built a plant to make them by the millions, and you'd be able to buy them from Walmart, probably after being greeted at the door by the poor SOB that originally invented it and went bankrupt for his trouble!
If you want to do cooling for free, my advice is to try sweating. It's the original, all natural, alternative to high electricity bills.
Oh...and I have plans for a solar clothes dryer that you can build at home for less than 5-dollars and it will save you $50/month on your power bills, if you're interested in that too. It's kind of like a rope tied between 2 trees.
Sorry...I'm getting pretty snarky this afternoon. May need to cut back on my caffeine.
Phil
I guess my take on it, as an engineer like snorkey, but NOT someone who has tried to design this would be: If it would work, that's what we'd all be using. I mean, I'm a good engineer, but there's better ones out there. If this was viable, someone would hold the patent, someone else would have already offshored the production to China, the Chinese would have stolen the idea from that person, reverse engineered it, built a plant to make them by the millions, and you'd be able to buy them from Walmart, probably after being greeted at the door by the poor SOB that originally invented it and went bankrupt for his trouble!
If you want to do cooling for free, my advice is to try sweating. It's the original, all natural, alternative to high electricity bills.
Oh...and I have plans for a solar clothes dryer that you can build at home for less than 5-dollars and it will save you $50/month on your power bills, if you're interested in that too. It's kind of like a rope tied between 2 trees.
Sorry...I'm getting pretty snarky this afternoon. May need to cut back on my caffeine.
Phil
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koditten
Well-known member
I like this. Reminds me of those Snickers ads that show the ugly side of people when they're hungry. Hoosier, do you need a snickers?
Anyways, you made your point. If it was that easy, we would all be doing it.
Later
KO
Teken
Well-known member
Pretty much sums it up . . . But, you can't give the guy a hard time for considering the idea. You never know the next guy might be *Just that guy*
Teken . . .
rlitman
Well-known member
Depending on your water table, I have heard of this done with a pair of wells, that circulate ground water (one pulls water, the other injects it back).
But you'd still need a heat pump, and without the closed loop, you need a more corrosion resistant heat exchanger.
Trey T
Well-known member
I think it's really expensive or time consuming to lay it horizontally 10ft below ground surface. I believe it's best to do it vertically and drill couple holes respect to the required heating demand/capacity. Even then, that's still expensive.
Sources say that it will take about 10yrs to see the saving due to high initial cost of the ground-loop and heat pump system.
On an episode of This Old House of the Essex home, IIRC, they have 3 wells @200ft each for the 1700 sqft home. They used mud rotary drilling method, and around my area, it cost about $30-40/ft to drill a typical water well (2-4") and completion. That's at least $24K already, and that's just too much for initial cost. And that's not counting the material, labor, equipments, and maintenance.
With natural gas getting cheaper and oil is still at bearable price, I don't see geothermal is a viable technology for residential homes at this time.
Sources say that it will take about 10yrs to see the saving due to high initial cost of the ground-loop and heat pump system.
On an episode of This Old House of the Essex home, IIRC, they have 3 wells @200ft each for the 1700 sqft home. They used mud rotary drilling method, and around my area, it cost about $30-40/ft to drill a typical water well (2-4") and completion. That's at least $24K already, and that's just too much for initial cost. And that's not counting the material, labor, equipments, and maintenance.
With natural gas getting cheaper and oil is still at bearable price, I don't see geothermal is a viable technology for residential homes at this time.