Home Forums General Discussion Using PV systems to heat hot water Reply To: Using PV systems to heat hot water

Richard Popenhagen

Hi Norman

Thanks for the response; I posted that article a few hours before I disappeared away on holiday, hence my delay in replying.

This certainly could be relevant; I guess I am trying to get my head around the practical details of how to make it work. Questions I have are:

·         Are DC elements available that would screw into a standard HWC element port?

·         I assume that this DC element would need to be controlled by a thermostat to prevent cylinder overheating during periods of low hot water demand (when people are away on holiday!!!)

·         You would still need a backup element connected to the 230 volt AC supply to provide heat during times of inclement weather. This would also need to have thermostat control, so you would need a hot water cylinder with dual element housings and dual thermostat pockets.

·         Obviously prioritising the PV supplied element to work first would be essential to maximise the gain, controlling the secondary boost element with timers as has been suggested in other posts as one way of achieving this (see below), but from my experience with solar hot water systems this is fraught with problems, especially if hot water demand profiles change, as they often do, even between week days and weekends.

There has been some chatter on this subject on ecobob, link attached for anyone that is interested: