Hi,
I did a small test collector using CPVC tubing and extruded aluminum radiant floor heat spreaders for fins.
Some construction pictures and performance test results here:
http://www.builditsolar.com/Experimental/CPVCCollector/cpvccollector.htm
Thought the group might be interested.
The collector is very easy to make and fairly inexpensive. In spite of the lower thermal conductivity of the CPVC compared to copper it still works pretty well thermally. I am somewhat doubtful about how well it will hold up over time.
Any thoughts on how to get better thermal coupling from the fins to the CPVC would be welcome.
Gary
