Saturday, July 28, 2012

Comparing the Performance of Two DIY Solar Water Heating Collectors -- CPVC vs Copper

Scott Davis has come up with an innovative and simple design for a solar water heating collector that uses CPVC pipes for the risers -- its easy to build and performs well.

Scott and his prototype CPVC collector.
The collector uses closely spaced CPVC riser pipes which are silicone bonded to a flat aluminum absorber sheet.    This makes for and easy and fast build.

I did a side by side performance test of Scott's design compared to the established DIY collector design that uses copper riser tubes spaced about 6 inches apart with thicker grooved aluminum fins to transfer heat into the riser tubes.  In this test, the CPVC design performed within 5% of the copper/alum collector, which I think is very good.

The side by side test of the two collectors.
There are a number of pluses and minus associated with the CPVC design compared to the copper/alum design -- things like cost, ease of build, performance, durability, and tolerance for stagnation temperatures are all important.  Which design works out best will depend on your situation -- I've tried to provide a little data on how the collectors compare in all these areas.  

I would be most interested in hearing your thoughts on the comparison and which collector you think would work out for your situation.

Full details on the performance and stagnation tests, construction, IR pictures, etc. for the two collectors...

Closer view of the test CPVC Collector.

IR image of the CPVC collector in operation
If you go ahead and build a CPVC collector, please let me know how it works out for you.


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