Best Hot Water Tank for use with Solar Panels

thefizz

I'm looking for advice on the best type of hot water tank for a hot press which will be heated by solar panels.

thefizz

I should add it will be heated by oil during the winter when the solar panels are not creating much electricity.

Lenar3556

PV panels heat the cylinder by means of an immersion, so there is no particularly special technology required. But you are correct to give this careful consideration.

On the one hand you have households who don’t ordinarily have their cylinder heated and are delighted to have often have ‘free’ hot water from excess PV.

But you will also have households who maintain their cylinder hot all the time to facilitate showers for example and for these customers, the cylinder is already hot and there is no space to add excess PV. To tell these customers to turn off their cylinder heating zone in the hope that it might be heated by PV (some days) will be very much a backward step, as there is no guarantee of hot water when they want it.

The solution to the above may be to use a much larger cylinder, that has an element for PV mounted low down and a coil from your gas boiler higher up.

Alternatively, and it would be my preference if you have the space is a second ‘preheat’ cylinder. This can be a basic cylinder with an immersion which feeds you primary cylinder. Excess PV Energry is dumped into the preheat cylinder. This will then be topped off by the oil boiler in your primary cylinder. (Or heated from scratch if there has been no sun).

Lenar3556

A separate consideration is if it is actually a good idea to use excess PV to heat your water at all?

At present the feed in tariffs when you export back to the grid may be higher than what it costs to heat your cylinder with oil.