Cohousing-L Mailing List: Cooling/Heating

[porcupin (porcupin]

Robin D. Ellison wrote:
> 
> --- You wrote:
> > Joyce, & group: I'd heard years ago about nataural air conditioning by
> > running ducting/tunnels/whatever underground (depth below 2 ft? length
> > 200 lf? 4" duct? 8"+?)- something I think the Mayans were into.
> > Cool, eh? Anybody out there know any specifics?
> > Jeffrey Leitch
> > Cohousing Northwest, Seattle WA
> 
> At a permaculture class, I heard about using such underground tunnels
> both for cooling in the summer and heating in the winter--particularly
> in reference to greenhouses.  I will see if I can find out more.
> --
> 
> Sanda and Brian Everette
> --- end of quote ---
> Eliot Coleman, of "Organic Gardener" fame, is experimenting with growing cold
> hardy veggies in unheated greenhouses in Maine.  He is trying a system he
> picked up from some Canadian research.
> 
> U shaped PVC tubes buried beneath the frost line with a 200ft run  with one 
> end
> in the greenhouse and one end above ground outside.    Cold air sinks in to 
> the
> end outside and comes out the other end at 40 degrees F.
> 
> This would work for a cool room anywhere.
> 
> Robin Ellison

Be carefull, air circulated through pipes in the ground is not fit for
working or food storage spaces due to the inevitability of mold spores. 
If you want to use the ground for cooling you are better off using water
run through buried pipes and then past a radiator of some sort. 
Remember that you will have to do something with the inevitable
condesation on the radiator.  
I did some reasearch and found a few web sites that explain various
systems. Here they are:

http://doegeothermal.inel.gov
http://www.eren.doe.gov
http://www.oit.osshe.edu/~geoheat/ghp/ghptable.htm
http://www.sandia.gov/eesector/gs/gt/heatpump.htm

I think that you will find these interesting reading.
John Poteet
Valley Oaks Village
Chico CA.