Earth Tubes Get a Winning Review...
 

Earth Tubes sound like a great idea, and they are. But there have been a lot of stories about their shortcomings.

Here's a winning story, with the reasons why:

My Earth Tube Story | GreenBuildingAdvisor.com


-AC

I buried 3 110' runs of 6" pipe in the same trench I dug to gravity daylight drain my footings out thru our hillside. I plan to use them to pre temper incoming fresh air into DIY HRV at night time. Daytime I preheat fresh air in a DIY solar air collector(soda can).

Earth Tubes for your existing ASHP????
 

Reading AC's earth tube success story makes me wonder if the basic earth tube idea would work for the outside unit of an existing air supply heat pump?? Or A/C unit. Please excuse the attached drawing!
One would simply need to trench in a wagonwheel pattern (or whatever would fit around your existing heat pump or A/C) of buried 4" or 6" earth tubes leading to the bottom of an annular jacket fitted completely around the outside of your then encircled heat pump condenser/evap fins. Most outside units are round or rounded squares so not too hard. Seal the annular top of the jacket, slope the earth pipes for condensate drains and your existing outside unit fan would pull its air only thru the heat tubes, into the bottom of the annular jacket and up thru it, thru the existing fins and out its existing center exit both winter and summer.
Nothing new inside your house, no mold/mildew worries, no hvac lines to break & move, a days trencher rent (or a teenager you need to keep busy!), $200 of maybe 4" Schedule 20 pvc pipe and a day to make the jacket - assuming no rocks! Would have to be better than exchanging with 20 degree outside air in winter and 90 degree in summer?????

My next project, I think.

In theory if you can keep the demand of building less than supply of earth tube it should be feasible. Certainly would perform better than air to air heat pump not using pre tempered air. Not confident the multi tube layout would draw air fully balanced without some monitoring and flow control. Might draw most of its air thru least resistance tube(greatly lowering ground heat potential. One or two concentric square tube layout would lessen this greatly, IMO. Great way to isolate mold trouble.

Simple solar air collector/s at the intake of tube could supply even more heat when sun makes it available. I plan an 6x8' one for the intake of my earth tube(simple soda can design) which will also hold the intake filter.

Sounds intriguing.

But if you're going to the trouble of trenching and burying stuff, you would be better served by burying plastic water pipe, and pumping water through the pipe. Water is a more efficient conveyor of heat than air.

The air tubes to temper air temp prior to an HRV, have a fairly undemanding job to do and a few degrees lift is essentially free, after installation.

But the magnitude of heat required to heat a house is much greater. Your ASHP must get it's heat from someplace.

The technology of Ground Source Heat Pumps has been tested and refined, and is available, no guessing required.

There is an organization called th International Ground Source Heat Pump Association. It is located in Tulsa Oklahoma, USA.

The general website is here: http://igshpa.org/

And the Manuals with all the info can be found here: https://igshpa.org/manuals

Best part of all is that you can DIY.

Check out this thread:

http://ecorenovator.org/forum/geothe...manifesto.html

Best

-AC_Hacker