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I don’t think a good solar electric hot water system would ever work if it was running only when the sun was shining. It takes _so much energy_ to get water up
by dclowd9901 7y ago
I don’t think a good solar electric hot water system would ever work if it was running only when the sun was shining. It takes _so much energy_ to get water up around the requisite 110+ degrees, that even a very efficient storage system wouldn’t benefit it all that much. Honestly, the best solar powered hot water system is a black plastic bag full of water in the sun. Anything else will require a battery bank at minimum.
- abraae 7y agoDepends on the size, but if you have even a modest size solar system you should be good. On a sunny day, a 2kw solar system can drive a 1kw hot water cylinder to full temperature easily. And to avoid legionnaires disease - a risk of inadequately heated water - you only need to drive the temperature up high from time to time, not continuously. Once a day is plenty.
- jdmichal 7y agoDon't use solar PVCs to heat water! Solar water heaters are much more efficient than PVCs. Even the lowest-efficiency system listed is 46%, compared to 19% for standard solar cells. https://en.wikipedia.org/wiki/Solar_water_heating#Energy_production https://en.wikipedia.org/wiki/Solar_water_heating#Energy_pro...
- nullc 7y agoIgnoring equipment cost, in many climates PV + a heat pump would outperform a plain solar water heater. :) [Silly to ignore equipment costs, sure, but if you have other uses for PV power ... using PV for heating water isn't necessarily nuts.]