| Because nowadays p.v. is cheap enough to heat enough water with far less maintenance costs and potential issues, at least that's my choice: I was undecided for a bit of time if going p.v. only or p.v. + thermal and in the end: - with p.v. I'm formally less efficient BUT in winter/cold but still sunny days my p.v. peak at a certain time for a certain time and my water heater start full power when there is enough energy, a solar thermal system take time to reach a sufficient temperature to make water (glicole) flow; - almost no external maintenance, just panels and wires, no leaks or freeze risks, no pipes etc; - no extra energy to make heat transfer fluid flow, witch means no pump, actually my heater is just an isolated "bowl" with a heat pump + classic electrical resistance and a big spiral pipe inside, so I have even no pressurized tank issues (water expansion) nor legionella problems etc; - for my needs 300l of waters heat also in the winter enough 100% on p.v. except if more than two days without Sun, overall cost is very limited, potentially I can use the optional thermal solar integration with a classic wood burning stove to heat water in emergency conditions. Why bother for thermal solar? With a big pool I understand but except for such case in witch solar anyway can't suffice for more or less large part of the year... |