text: what material/membrane do i use for these pipes? see, basically i'm working on this project where i use these pipes that run subsurface in fields and cool the ground during the hot tropical summer. these pipes carry cool water at a temperature of about 21 degrees c. the pipes should be able to take the heat from the soil and transfer it to the water but at the same time be leak proof and should be able to withstand mechanical vibrations. i need to know a specific material/membrane that will suit my needs. this technology exists and is usually called geothermal heating/cooling.  if you do a search on that, you should be able to see what kind of piping they use.