EcoRenovator - View Single Post - Idea: DIY Ground Source add on to Air Source Heat Pumps

Ron342 · 03-06-15, 03:47 PM

A few yrs ago (20) I had much the same idea while living in a town house with a heat pump with a roughly rectangular outside unit with somewhat rounded sides on the case - I concluded that the tube sizes in a larger wrap around condenser/evap coil wouldn't flow enough given the small drop/rise in geo water loop temp you had to work with - but I had a friend that had a bunch of large truck radiators (not the oddest of things he saved!) I borrowed 4 of them that would fit in a square outside the outside heat pump unit, connected them at the sides and blocked off the space between the top and bottoms of the radiators and the heat pump housing so no air leaks and, since I only wanted to try this and had no geo field, ran city water thru the radiators ,- I think I wound up with them hooked up with a pair in series and the incoming city water divided in two to feed those 2 series pairs. The heated water simply ran out in a restricted drain to make a mess in the yard. It was easy to hook up a solenoid valve so the water ran whenever the fan came on. It took a lot of water!
The effect in summer was dramatic - I didn't have a clamp meter but did have a run timer (read bedroom clock) - the run time on roughly the same hot 90 degree days was about roughly 1/2 to 2/3 of the unassisted unit and I think the current draw was down too. I was going to try it in winter but freezing temps would have been a big problem. I took it down when the friend had sale for the radiators.
I was going to make a neater try at the same idea when I had a house and geo bore by forming a circular annular fiberglass envelope around the existing air coil, killing the fan and pumping the geo loop water with antifreeze into the envelope directly over the enclosed air coil. Sealing the refrigerant in and out lines in the fiberglas case seemed the only problem. Kids happened to me as well though and I've enjoyed them more than fiberglass!

Nokiasixteth - I'm dying to know how you drilled to 250 feet - we are mostly clay and sand here but that would still be a homemade feat!

03-06-15, 03:47 PM	#8
Ron342 Apprentice EcoRenovator Join Date: Feb 2010 Location: Maryland Posts: 120 Thanks: 26 Thanked 12 Times in 8 Posts	A few yrs ago (20) I had much the same idea while living in a town house with a heat pump with a roughly rectangular outside unit with somewhat rounded sides on the case - I concluded that the tube sizes in a larger wrap around condenser/evap coil wouldn't flow enough given the small drop/rise in geo water loop temp you had to work with - but I had a friend that had a bunch of large truck radiators (not the oddest of things he saved!) I borrowed 4 of them that would fit in a square outside the outside heat pump unit, connected them at the sides and blocked off the space between the top and bottoms of the radiators and the heat pump housing so no air leaks and, since I only wanted to try this and had no geo field, ran city water thru the radiators ,- I think I wound up with them hooked up with a pair in series and the incoming city water divided in two to feed those 2 series pairs. The heated water simply ran out in a restricted drain to make a mess in the yard. It was easy to hook up a solenoid valve so the water ran whenever the fan came on. It took a lot of water! The effect in summer was dramatic - I didn't have a clamp meter but did have a run timer (read bedroom clock) - the run time on roughly the same hot 90 degree days was about roughly 1/2 to 2/3 of the unassisted unit and I think the current draw was down too. I was going to try it in winter but freezing temps would have been a big problem. I took it down when the friend had sale for the radiators. I was going to make a neater try at the same idea when I had a house and geo bore by forming a circular annular fiberglass envelope around the existing air coil, killing the fan and pumping the geo loop water with antifreeze into the envelope directly over the enclosed air coil. Sealing the refrigerant in and out lines in the fiberglas case seemed the only problem. Kids happened to me as well though and I've enjoyed them more than fiberglass! Nokiasixteth - I'm dying to know how you drilled to 250 feet - we are mostly clay and sand here but that would still be a homemade feat!