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Old 12-26-18, 06:28 PM   #4
AC_Hacker
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Default Your PVC Scheme...

Your tube-in-tube idea is curious.

I have read your post, and in trying to be the best devil's advocate possible, I came up with this:

* PVC is not usually used for GSHP systems because earth can move and shift and PVC is brittle in comparison to HDPE. HDPE is extremely tough, and it has an added benefit in that can be heat welded. The official heat-welding equipment is expensive, but you can rent it, or you can do what I did, and make your own out of parts from junk stores.

* If you're looking for someone to tell you what the efficiency would be of a tube-in-tube such as you have suggested, existing information would be very difficult to find. There does exist a very large body of information on the characteristics of buried HDPE. It may very well be a good idea that you have there, but I suspect that you would need to develop the data yourself. Construct one full size tube-in-tube unit, and dig and bury it in a hole such as you have mentioned. Then do some testing and look at your measured results. That way you can proceed with knowledge regarding if you need to put in more units than you estimated, or less or try another idea.

* Digging holes can vary from being very easy, to being your worst nightmare. You need to know what the hole-digging conditions are in your specific area. By area, i mean within a few hundred feet. Contact well diggers, they know all about this stuff.

Good luck on your project. Keep us posted. We love to see photos.

Best,

-AC_Hacker
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