Just curious if anyone tried or know of some one that has tried to run pex pipe underground in a loop like a geo thermal system to cool the house in the summer? Instead of heating the water in the boiler we would be trying to cool it. This may not be enough to cool the house completely by itself, but I would think it would at least supplement the AC.
OWB Cooling?
- Thread starter hoyt38
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Kingsley
ArboristSite Guru
This has been brought up before, but the condensation would be a BIG problem.
Good point, Never thought of that.
Davej_07
ArboristSite Operative
It could be used if you use hot water coils in a forced air system, but you would have wet floors from the condensation if you have baseboards. The other problem you would have is that with the forced air system you wouldnt be removing the moisture from the air as readily as the AC system.
Dave
Dave
AIM
Addicted to ArboristSite
I tried it once back when my lines were in the ground. Didn't do anything.
90' probably wasn't enough though. Plus I don't think geothermal lines are insulated.
90' probably wasn't enough though. Plus I don't think geothermal lines are insulated.
I was thinking about using a plate exchanger to cool the water with, until Kinsley brought up the good point about condensation. The cool water would cause condensation in the air handler as well. It was just something I have been thinking about for a while and did not understand why it would't work and I knew you guy's would have the answers.
bluestem
ArboristSite Operative
What if you were using glycol in your system instead of water?
Kingsley
ArboristSite Guru
Glycol
It is the humidity in the air that is collecting on the lines making them wet, not the liquid escaping the line. Glycol would make no difference.
It is the humidity in the air that is collecting on the lines making them wet, not the liquid escaping the line. Glycol would make no difference.
midwest_170
ArboristSite Operative
I know this is an old thread, but why couldn't you just design a catch system in you duct and plumb it to a drain? I understand it wouldn't work if you have baseboard or floor heating, but if you are using a forced air system in a basement I would think that you could have enough verticle run of non-insulated duct to gather most of the moisture before entering a insulated duct. Maybe i'm way off.
taskswap
ArboristSite Operative
Yes, you could do that. But forced-air systems are only a subset - lots of boilers are plumbed into hydronic systems, and even more new installations because they can do radiant sub-floor installations.
For the forcer-air heat exchanger inserts you still have to deal with the efficiency issue. You need a very long, large loop buried quite a bit underground - 6' is ideal according to many of the sites I've read (I had planned to do this myself). Otherwise the water doesn't really get cold enough - 55-60 is "cool", but not "cold" - a modern A/C chiller will get down to 45 or less, cooling much more quickly. That doesn't have to be a blocker, but it's worth thinking about. (It's like heating - you can run your baseboards at 145, but they're MEANT to be run at 175+, so they take a lot longer to heat if you don't do that.)
Maintenance is also a pain if you get a leak. Most of the people I saw who posted about this online ended up putting in supply/return manifolds with individual valves, and 3-6 (4 seemed most common) isolated loops in the buried portion. That way if there was a leak they planned to just shut off that one line and leave it.
I ended up skipping the whole thing. A local veteran's benefit store was selling window units in pretty decent shape for $50-$75 apiece. When I added those up and included the cost of electricity for running them for 3 years (and these are really low EER units), and compared that to the cost of renting digging equipment, buying the piping and manifolds plus the extra pump, the electricity to run the PUMP, the heat exchangers, etc., the math just didn't work. Maybe it would if you happen to have that stuff lying around?
Interesting idea: one guy didn't bury his - he sank the loops into a pond. Plenty of thermal mass and no digging. There's an idea.
midwest_170
ArboristSite Operative
Thanks for your reply. I have a central air unit, but it's the same age as the house, 17 years. I struggled to keep up last year with our heat. I have a 3 ac yard so getting line length is not a problem and a friend of mine has a trencher. I'm trying to justify it, but sounds like a big headache. Im mechanically inclined and I'm a design engineer, but I'd feel more comfortable taking on this project knowing there is an advantage over a central unit once its finished.
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I really don't think there'd be a benefit at all over central AC by the time you are all done.
I've been in buildings with geothermal cooling and it's pretty humid still. If you run it too much the floors get wet.
You will be better off just replacing your central AC unit with a newer more efficient model.
I've been in buildings with geothermal cooling and it's pretty humid still. If you run it too much the floors get wet.
You will be better off just replacing your central AC unit with a newer more efficient model.
mtfallsmikey
Addicted to ArboristSite
Just dig in and do a nice geothermal system and be done...
