[Shop-talk] solar pool heater

[Wayne]

old dirtbeard wrote:
> I have a ~20K gallon swimming pool here in the Los Angeles area and would like
> to build a solar pool heater.
> ....
> .... I was wondering if I could fabricate a
> "solar collector" out of PVC pipe painted black or use ABS pipe either in a
> parallel or "serpentine" array with a small, efficient, separate pump (I have
> two inlets to the pool and could just create one "loop" for the solar heater).

PVC pipe starts to melt or "go plastic" around 190 or 200 dF, which 
could be a problem.  It's also not UV resistant and will get very 
brittle and fall apart in direct sunlight.  The gray PVC sold for 
electrical conduit is supposedly UV resistant.  CPVC (the yellowish 
stuff) is normally used for hot water home plumbing.  Not sure of its UV 
suceptibility.  Paint might block enough of the UV to help that problem, 
but it would raise the operating temp.

I don't know much about the ABS stuff, but that might be your best bet.

The superior heat conductivity of copper, and wider operating temp range 
  would make it a better choice;  but that stuff is still real expensive.

-Wayne