flcruising wrote:Not to be critical, but your design has 1 huge flaw - most of the piping is not exposed to the sun's rays!
You would gain ALOT more efficiency by going larger with your box and coiling the pipe up in it so every coil has sun exposure.
http://rimstar.org/renewnrg/solar_pool_ ... diy_fp.htm
Lot's of useful information here - http://builditsolar.com/
No offense taken...I learn by critical constructive info. Im sure that i could extract more heat from the suns rays if the Pex was more exposed directly to the sun ; however Im already getting higher water temps than what i require . If I needed a greater Collector reseviour and/or higher output temps. then id certainly consider exposing the Pex to the sun more in addition to adding another 300' Coil or more. My aim here was to build something compact , inexpensive , simple, and to just satisfy my individual hot water needs , and not beyond.
I like the site you attached of the Italian Solar installation, but they should have installed those Coils in a long Wooden Box with window so they could take advantage of radiation plus convection heat gain .