<<Jim Franklin wrote:
> How does the ground temperature not eventually reach equilibrium with
> the shop? I can't see the transfer of heat in dirt being fast enough
> to absorb a summer's worth of 85+ temps.
It's not a straight heat exchanger. It's a heat pump, with compressor,
refrigerant, and all the same stuff as a regular air-source hat pump. >>
for the record, the above is the "normal" system.
I was trying to state that I made a simpler version in the shop where I did
NOT use a refrig system...just used a 12VDC ($39) pump to slowly circulate
(I wanted to vary speed/ flow; easiest way was 12 V DC with variable supply
voltage) directly through water-coils in the air handler (this was a special
order). We all know that the R22 pump is the energy user...this system was
under $22/ mo to run (with air handler fan) continuously.
Heat gain from windows upstairs made that space gradually warm up over the
summer.
Downstairs (no windows) stayed 8 deg cooler on avg. Space is 40 x 30 x 12
ft first floor; x 9 ft second flr.
I hope to play with this system over the winter. I want to make a heat
exchanger to allow me to circulate the ground loop water against an R-22
based coil, and likewise the water loop to the air handler on the other coil
of an R-22 system. I've found a small R-22 unit that is self contained,
but designed to exhaust the "dump" side of the system through a 6 inch hose,
sim to a dryer vent.
The idea is that this will add greater "concentration" of the heat gradient
between ground loop and interior...same as a commercial set up, just home
built, smaller...?more fun?
The inside air envelope in my shop is so tight (0.2 air exchanges per hour)
and insulated (R-60 ceiling and R-49 walls) with the ICF (Insulated Concrete
Forms) construction, that commercial systems are all about 3 times bigger
(BTU) than I need. The direct ground-loop to air-handler experiment was
designed to test that theory.
Results of this "playing" will be applied when I build the retirement house
in a few years. I really want minimal monthly HVAC cost/ energy use, since
it seems that it can only go up or become more scarce as I get older...
Whatever system you might use to do the cooling, you can't do better than
starting with ICF construction....IMO.
Paul
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