Dryer hose and geothermal greenhouse

I've been thinking a lot about the Russ Finch geothermally heated/cooled greenhouse design, where he's buried a long plastic pipe which he circulates air through.

But I'm thinking, "plastic isn't a very good heat conductor"... but aluminum sure is!

So I was wondering, do you think there would be a way to bury aluminum clothes dryer tubing in such a way that it wouldn't crush under the weight of the soil?

Dryer hose is pretty fragile. I use four inch convoluted French drain hose, you can almost stand on it. The effort of having to unbury a collapsed hose or the added effort/cost of some kind of cover like  perhaps septic infiltrator t-pees would influence me.

I accidentally tear dryer hose installing it sometimes.  I don't think there is a way to have both ground contact, and have it be able to support the weight of the soil.  Drain tube seems to transfer heat/cold well enough, given the success people have had doing it, and as Robert said, it's very strong relative to dryer house.

The biggest transfer of heat in an air to earth heat storage system occurs when the water condenses on the wall of the tubing.
This creates a fair amount of moisture, which drips into the earth via the perforations in the pipe.
Mold and mildew is controlled by the organisms in the soil surrounding the pipe.
Dryer hose is impermeable, so it it is likely to develop mold and mildew, much like the earthtubes that have been tried in the past.

If I were concerned about heat transfer, I would use something like blue barrels, split in half, or brick lined passages with tile roofs.

You make it up on surface area.  While heat transfer is low the pipes have a huge surface area.  Think of it this way if you have a 4 inch pipe it is basically 1 foot in circumference.  So if it is a long run of pipe you still have huge surface area.  A 100 foot run of pipe will be 100 square feet of surface area.

[quote=William Bronson] The biggest transfer of heat in an air to earth heat storage system occurs when the water condenses on the wall of the tubing.
This creates a fair amount of moisture, which drips into the earth via the perforations in the pipe.
Mold and mildew is controlled by the organisms in the soil surrounding the pipe.
Dryer hose is impermeable, so it it is likely to develop mold and mildew, much like the earthtubes that have been tried in the past.

If I were concerned about heat transfer, I would use something like blue barrels, split in half, or brick lined passages with tile roofs. [/quote]

Perforated vs non-perforated seems to be very much a point of contention among people building these system.  The "citrus in the snow" guy uses non-perforated pipe and says he has no mold or mildew issues.  Other people use perforated pipe and swear you will have terrible problems if you don't.  I don't know the real answer, or how I am going to build mine when I do it.  I'm leaning toward non-perforated because I'm concerned that perforated pipe may fill with water.



As an aside, anyone know why that quote didn't work correctly?

I don't think we are looking for an immediate dump of temperature transference. I think that transference isn't dependent on the material of the duct work so much as it is the ambient temperature of the surrounding fill. The reason the runs are long in some of these systems is to take advantage of the thermal mass along that run. Condensation within the duct work being addressed with perforated pipe makes sense. Longevity of the dryer hose being buried would also be a consideration.