Solar PV with 2 immersion tanks

[juloa]

Hi,

Recently moved in with my wife and 3 kids to a house with 5 kw solar panels on the roof and there are 2 immersion tanks. The PV system is grid-tied and am not sure what power comes from and goes to the grid. I want to know if I can splice the two tanks to heat from the pv power and how?

Thanks

[AW10]

There's no manual switching to be done - the energy you import equals what you're consuming less any being generated by the PV system. For example if you're using 3300 watts (3000 for the immersion heater and 300 as the overall background load for the house) and your PV system is generating 2500 watts you will only import 800 watts.

There are proportional controllers for resistive loads such as immersion heaters that only give them as much power as is being exported - look for boxes like the immersun and solar iboost to name 2. They let you harness the surplus PV. In the scenario above they would only supply 2200 watts to the immersion heater (the 2500 being generated minus the 300 watt background load) meaning the import value would be zero. But the payback period will depend upon how your hot water is normally heated and what time of day you need to heat the water.

[VEX]

We have an immersun here and over the summer the oil boiler doesn't come on at all.

We do have a super dropper lagged hot water tank and the immersion is set higher than the boiler stat.

V.

[The Restorer]

I think the Solarcache will be able to control multiple heaters.

Just check though, on a 5kw system you may also have an export meter connected. If this is the case you may want to see if the export tariff will give you more money than say using gas/oil to heat your water.

[frair]

There are many threads going on about solarimmersion in http://forums.moneysavingexpert.com also checked with a couple of my electrical supplier friends. They say it does a pretty good job with multiple loads.

[Oakey]

Look, it's the invasion of the shills.