under ground hot water pipe material

geo_29

What is the best pipe material to use for under ground hot water pipe material? The pipe will be used for dumping waste heat from a combi solar water heating system in the summer. The ME specified polyethylene compound material in accordance with ASTM D-2513 but the builder is worried about gophers or rats being attracted to the warmth & then chewing through the pipe so is proposing type K copper. I understand that copper can corrode in some soils. Any suggestions from experience, please?

Jean-David Beyer

This was a super big problem for the company I used to work for.

I used to work for an outfit that was part of AT&T. Another part of it was called Long Lines and had many thousands of miles of buried underground cables. Prarie dogs, gophers, etc., kept chewing up the cables. They need to do this because their front teeth grow rapidly and they need to wear them down. The company tried wrapping the cables with armor steel tape, but this did not help. They tried poison, but that did not help either. They tried different kinds of plastic. This went on for decades. Then some engineer got a bright idea. He had them make the cables very large diameter. The critters could not get a good enough grip on the cables to harm them.

meplumber

This is what we use.

We use Uponor Ecoflex when we need to run underground heat lines. It is pre-insulated and made for underground installation.



Maybe this helps.



http://www.uponor.com/solutions/indoor-climate-solutions/local-heat-distribution/pre-insulated-pipe-system.aspx

hot_rod

does it need to be underground?

there are a few brands of wall mounted convectors for dumping heat. Apricus has an HD-25 dump convector. Other evac tube manufacturers offer them.



I remember seing an interesting dump radiator recently that piped directly into the return back to the collector. A snap switch would kick on a fan once the return reached 190F and cool down the system.



With flat plate style collectors you can pump back through them in the evening and dump excessive heat. Most of the new solar controllers have that function built in called re-cool or system cooling for that purpose.



The first and best choice would be to use or store that energy instead of running a pump to dump away "free" energy. Depending on how much excess you have an additional tank could provide enough extra space.



Or at some point consider a drainback system and never worry about dumping, just shut 'er down.



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