Using solar PV to heat water in an immersion heater.

pinnks

I too think solar thermal would be good for hot water at those latitudes, with or without PV for electricity depending on available space for panels.  Adding a diverter to any PV you install may or may not be worth the investment if you have solar thermal as those panels should give you hot water on any days on which the sun is strong enough to generate PV, meaning little or nothing would be diverted from the PV system. And on days with no sun, neither PV nor thermal will produce anything worth talking about...

I have a typical 3-bed house immersion tank (200 litres I think) and with 2 of us showering and doing other normal hot water stuff in the house (dishwasher and washing machine are cold feed) we need to feed the immersion with about 2.5 to 3kWh per day to keep the tank topped up.  If you go PV, whether low voltage (how does that work when you get 600V DC or whatever from the panels?) or 230V AC via an inverter and diverter, you need enough wattage on the roof to feed enough into the tank...   

Solarchaser

The panels individually create around 20-40v as standard, its by linking them in series to form strings that you get high voltage dc 😀 

Reed_Richards

Pile_o_stone said:

This site has information about linking a 200w 12v immersion heater that;s connected to a wind turbine. I think you have to have a load on a wind turbine or they spin to bits in stormy weather, so they often attach a heating element for backup. I assume the basic information can be applied to solar rather than just a turbine.

http://www.reuk.co.uk/wordpress/heating/200w-12v-immersion-heater/

But a 200 W immersion heater would take 15 times longer to heat water that a standard 3000 W immersion.  That might just about work with a wind turbine running day and night but I cannot believe it is compatible with solar.  The thing about solar is that you get a lot of power for a relatively small fraction of the day.  You need to use all that power whilst it's there.    

Pile_o_stone

Reed_Richards said:

Pile_o_stone said:

This site has information about linking a 200w 12v immersion heater that;s connected to a wind turbine. I think you have to have a load on a wind turbine or they spin to bits in stormy weather, so they often attach a heating element for backup. I assume the basic information can be applied to solar rather than just a turbine.

http://www.reuk.co.uk/wordpress/heating/200w-12v-immersion-heater/

But a 200 W immersion heater would take 15 times longer to heat water that a standard 3000 W immersion.  That might just about work with a wind turbine running day and night but I cannot believe it is compatible with solar.  The thing about solar is that you get a lot of power for a relatively small fraction of the day.  You need to use all that power whilst it's there.    

Yep, much better to either install PV with an iBoost type diverter (preferred) or install solar thermal. I supplied the link so the OP had all of the options.