> How much of the heat energy supplied to the hot water reservoir > > is direct solar heat? None? Any? As I describe it in basic form =3D none. If you use the panel as a thermal heater as well you can get both. And cooling a PV panel gives up to 10% more power out. R --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .