Earthtube shop heater/cooler

The stainless steel pipe runs underground for about 35' and comes up in my greenhouse where I can decide whether I want it to connect to the fan for cooling or leave the fan open for pulling heat from the greenhouse into my shop.

I would be interested in knowing if a concept like this could work to cool a "greenhouse" enough in a hot climate (like Phoenix) to make it reasonable growing conditions during some of the hottest summer months. I know Zach Weiss has a lot of experience with this technology and using it for the heating aspects. I am curious of yours and his thoughts on the possibility of cooling a structure (with the suppliment of shade cloth) to a temperature in which plants would actually survive during the summer. I think if you could get that side of things figured out, with a low or not input cost, in a harsh enviroment like the desert, then it could be used to extend food production year round there too.

Hi Jen,
I mostly use this to cool my shop in the summer, but we have cold winters here that make the ground cooler than a place like Tucson. I think they could work anywhere, but I would put the tubes deeper in warmer climates.

I like the control of a variable speed fan instead of relying on natural circulation.

What kind of tempature changes do you see when cooling your shop?

Jen,

I agree -- it depends a lot on your earth temperatures in Phoenix. A good resource is this: http://www.wcc.nrcs.usda.gov/scan/
And, depends on what seasons you want the cooling. The summer soil temperatures will be warmer, but you will still likely get a small cooling effect.
We generally find drops of 5 to 40 degrees in cooling in our Colorado applications, but we now have some in Alaska and some to be going in warmer places too.
Lindsey
Ceres Greenhouses
ceresgs.com