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

agentk

could i have details too many thanks

energysavingexp

solar58 wrote: »

I would be interested too

Thanks
Dave

Sent you them

noncom_2

I'd be interested in seeing this too please! PM me if possible, thanks.

raider

Me to please ESE :beer:

energysavingexp

raider wrote: »

Me to please ESE :beer:

ive sent you all a pm with it

thenudeone

Thanks:beer:

Very interesting idea. A circuit diagram would help;)

But rather than having to put one of the sensors outdoors in the sunlight as the trigger (with the inherent problems of weatherproofing and cable runs), can anyone think of a way to use the higher flash rate of the LED on the generation meter to activate the system?

Effectively I need a circuit which will trigger a relay if the flashes are above a certain (variable and chooseable) frequency.

Kernel_Sanders

thenudeone wrote: »

But rather than having to put one of the sensors outdoors in the sunlight as the trigger (with the inherent problems of weatherproofing and cable runs), can anyone think of a way to use the higher flash rate of the LED on the generation meter to activate the system?

That would be an accurate measurement, but wouldn't that require a program (on a cheap mobile phone maybe) to do the calculation? I'm thinking here about a rolling 36 second period. Failing that, I'm going to mount mine on a window sill parallel to the array, and also pitched to match the roof slope.

Dave_Fowler

thenudeone wrote: »

Thanks:beer:

Very interesting idea. A circuit diagram would help;)

But rather than having to put one of the sensors outdoors in the sunlight as the trigger (with the inherent problems of weatherproofing and cable runs), can anyone think of a way to use the higher flash rate of the LED on the generation meter to activate the system?

Effectively I need a circuit which will trigger a relay if the flashes are above a certain (variable and chooseable) frequency.

There's no great problem in achieving this using a combination of analogue and digital circuits. I'm working on a very simple design at the moment, but family commitments mean I won't be able to put much time in before mid April. A simple pulse-rate detector with variable threshold can be made with off-the-shelf components for very little cost.

However using the wonderfully simple circuit suggested by ESE I can't quite work out what will happen under the following circumstance:-

I've chosen to turn a 2.5kW heater on when the panels are generating 3kW. (This allows a base-load of 500W). Let's say a 1kW toaster is now turned on. The import meter LED starts to flash so the logic device turns off the 2.5kW heater. Import LED stops flashing (only 1.5kW in use, 3kW generated) - therefore 2.5kW load turns on again. Import LED starts to flash again, heater load turns off .....

What is needed is a method of varying the 2.5kW load to match the surplus energy. The use of a phase-angle controlled triac - as used in some variable electric heating systems - can cause a great deal of electrical interference if the design is not closely controlled and screened and possibly would not appear as a reduced load to a modern meter because of the 50Hz pulsed load. (Can anyone help with this knowledge?)

A phase-angle controlled system would probably cost around £50 if you built it yourself, but you'd have to be quite adept at electronics building and also understand the dangers of 240V circuitry.

Dave F

raider

energysavingexp wrote: »

ive sent you all a pm with it

Hi energysavingexp. I've not received a pm with it yet, could you re-send?

Thanks

Kernel_Sanders

Dave_Fowler wrote: »

However using the wonderfully simple circuit suggested by ESE I can't quite work out what will happen under the following circumstance:-

I've chosen to turn a 2.5kW heater on when the panels are generating 3kW. (This allows a base-load of 500W). Let's say a 1kW toaster is now turned on. The import meter LED starts to flash so the logic device turns off the 2.5kW heater. Import LED stops flashing (only 1.5kW in use, 3kW generated) - therefore 2.5kW load turns on again. Import LED starts to flash again, heater load turns off .....

What is needed is a method of varying the 2.5kW load to match the surplus energy.

But he isn't attempting to vary the draw of any one appliance. All he is doing is making sure that no expensive daytime power is imported, so if that only requires a simple circuit then that is an advantage.