offgridQLD wrote:This brings up another topic that was discussed before . Is it better value to just add more PV and a well insulated electric element hot water system (tank) or a solar hot water vac tube. As once the solar hot water heater has heated the water it's gong to wast. Once PV - electricity has heated the water its perhaps easier to find other uses for the extra electricity potential.
That's what I'm looking at, using water that has already been heated by the sun in a ET system, rather than using what I'd call a inefficient form of heating by the washing machine or dishwasher.
Yes, on a offgrid system you aren't really paying for it (ignoring the long term costs), but I feel that using your PV power to heat up water in these devices is a waste of effort and can be better used, i.e. discharging your batteries unnecessarily.
Even on a grid powered house, there would have to be more tangible savings over the lifetime of living there if you were able to supply already heated water to those two devices. Particulary when these smarter devices sense when the temperature has been reached before continuing the wash cycles, and therefore shorter overall washing cycles.
I was talking to someone the other day about outdoor spas, and was discussing the heating options, and the thought came to mind about using SHW through a closed system that has some form of 'radiator' immersed somewhere in the spa (in the pump/filter system), that was set on a timer to only operate during normal daylight hours.
60+ degrees from a SHW system with a small pump, like the pump used to move the water from the tank to the ET's , with a thermostat to turn off the pump when temperature has been reached whilst the timer is turned on.
I would love to have a spa, but that ain't going to happen for several years after building the new house.