device to use unused soler pv export power to run heater or hot water

Kernel_Sanders

EricMears wrote: »

You could of course supply a 1kw immersion heater via a 230/115 stepdown transformer when it would only draw 250w (plus transformer losses).

Or any other power heater will drop to a quarter of its 'normal' rating.

Do these transformers come in 'piggy-back' plug-in form and if so, would they reduce a 2.2kW kettle's draw to 550W (+ transformer's demands)?

EricMears

Kernel_Sanders wrote: »

Do these transformers come in 'piggy-back' plug-in form and if so, would they reduce a 2.2kW kettle's draw to 550W (+ transformer's demands)?

It's not something I've actually done - just a vague inkling of what I might do one day.

I was thinking of the sort of transformer you'd buy (hire ?) so that you can use 'professional' building site equipment at home. They of course come in different sizes but I'm sure there would be one to suit a 110v 750w power drill / angle grinder etc. Probably better to gt one rated for even higher wattage just in case they're only designed for short bursts of use whereas a derated immersion heater would need to be on for several hours.

Bucorvus

Please send details - thanks!

energysavingexp

Bucorvus wrote: »

Please send details - thanks!

sent you it via pm

rotate

Hi
Thanks for the information.I am in the process of making a unit at the moment.
However I am simplifying it,in that I only want the device to switch on the immersion heater when the sunlight is strong enough to generate 2kw or greater.
As the house will usually be unoccupied during the day,there will be no other high load items running.
Also if the immersion pulls 2.5 kw and I am generating 2 kw then I take 500w from the grid.This is still cheaper than running the gas heating to heat the water.
I can then turn the gas boiler off in the Spring/Summer.

energysavingexp

rotate wrote: »

Hi
Thanks for the information.I am in the process of making a unit at the moment.
However I am simplifying it,in that I only want the device to switch on the immersion heater when the sunlight is strong enough to generate 2kw or greater.
As the house will usually be unoccupied during the day,there will be no other high load items running.
Also if the immersion pulls 2.5 kw and I am generating 2 kw then I take 500w from the grid.This is still cheaper than running the gas heating to heat the water.
I can then turn the gas boiler off in the Spring/Summer.

you'll find this a very cheap way to control your immersion heater. total cost around £10 for 1 board and ssr.
good luck with it

greyteam1959

Would be interested in your device.
Please could you pm me the details.
Many thanks in advance for sharing your knowledge.

energysavingexp

mervyn11 wrote: »

Would be interested in your device.
Please could you pm me the details.
Many thanks in advance for sharing your knowledge.

yep on its way to you now

mymerrywidow

sounds interesting.

Kernel_Sanders

rotate wrote: »

Hi
As the house will usually be unoccupied during the day,there will be no other high load items running.
Also if the immersion pulls 2.5 kw and I am generating 2 kw then I take 500w from the grid.This is still cheaper than running the gas heating to heat the water.

Surely you could have eliminated even that small expense by fitting a 1 kW element instead. If you're out during the day, then I'd have thought the system would produce 1 kW for at least double the time that it produces 2 kW.