So now I have a solar PV system how do I make the most of it???

tinkytonkytank

We are getting a widget that diverts unused electricity to heating water, so that we'll export no energy. But because they don't meter the exports, we'll still get paid for exporting it ... very unfair on those that are paying, but I'll leave the questionable morals out of the discussion!

orrery

tinkytonkytank wrote: »

We are getting a widget that diverts unused electricity to heating water, so that we'll export no energy.

Not entirely true. It will depend on how big the immersion heater is and where it is fitted in the tank.

I have a top-fitted immersion which is only 21" long so only heats the top of the tank - not enough for both a bath and a shower. Once it has heated the water, it shuts down and we start exporting again.

We need a longer immersion, but the longest that could be fitted is 30" and that still wouldn't reach to the bottom of the tank. So, I've had a de-stratification pump fitted (which pumps the hot water from the top of the tank back into the bottom to mix it all up) but that doesn't work - it seems impossible to get the air out of it.

Of course, if you have an immersion fitted at the bottom of the tank, then you should be OK.

Dave_Fowler

orrery wrote: »

Not entirely true. It will depend on how big the immersion heater is and where it is fitted in the tank.

I have a top-fitted immersion which is only 21" long so only heats the top of the tank - not enough for both a bath and a shower. Once it has heated the water, it shuts down and we start exporting again.

We need a longer immersion, but the longest that could be fitted is 30" and that still wouldn't reach to the bottom of the tank. So, I've had a de-stratification pump fitted (which pumps the hot water from the top of the tank back into the bottom to mix it all up) but that doesn't work - it seems impossible to get the air out of it.

Of course, if you have an immersion fitted at the bottom of the tank, then you should be OK.

I've fitted a destratification pump. As soon as the immersion thermostat switches off the pump starts. The entire tank is heated virtually every day.

It was very easy to fit and should pay for itself quite quickly - component parts purchased from eBay and local plumbing store.

Dave F

orrery

Dave_Fowler wrote: »

I've fitted a destratification pump. It was very easy to fit ...

Ah ... that's where we start to disagree. I have thus far failed to get it going - I just can't get the air out. The controls are no problem, the electrics are fine: the SolarImmersion provides the control to turn the pump on and I'm going to add a stat at the top of the tank (so it runs when the solar is heating the water AND the water is above a minimum temperature).

Have you fitted non-return valves in both the de-strat loop and the cold feed (to stop it pushing back into the cold tank and pulling air from the overflow vent)?

Dave_Fowler

orrery wrote: »

Ah ... that's where we start to disagree. I have thus far failed to get it going - I just can't get the air out. The controls are no problem, the electrics are fine: the SolarImmersion provides the control to turn the pump on and I'm going to add a stat at the top of the tank (so it runs when the solar is heating the water AND the water is above a minimum temperature).

Have you fitted non-return valves in both the de-strat loop and the cold feed (to stop it pushing back into the cold tank and pulling air from the overflow vent)?

Hi Orrery,

I've fitted a non - return valve in the de-strat loop, but not in the cold or expansion feed. I run the pump at minimum speed and have had no problem with it drawing air down the expansion pipe. The water head is about 2 metres.

I was worried about putting a non return valve in the expansion pipe as it would restrict the flow should the thermostat in the immersion heater or GCH fail and the water boil.

Dave F

allan474

Hi there

I have 2 heaters one is 5 kw and the other one is 4 kw. Would one SolarImmersion be enough to handle this load?

Thanks
Allan

orrery

allan474 wrote: »

I have 2 heaters one is 5 kw and the other one is 4 kw. Would one SolarImmersion be enough to handle this load?

The manual says 4kW maximum. If you plan to use it as it is meant to be used (supplying varying power as is surplus to requirements) then you will be connecting to its modulated output and therefore the 'heater' must not have any electronics in it - although an old fashioned thermostat is fine (the knob variety that clicks on and off as you turn it up and down).

allan474

Hi,
Thanks orrery for that, my electrician customized it for my heaters with a few tweaks and of course with the thermostat. Its working fine.

orrery

I've bought an electric car and now realised that there isn't a cat in hells chance of charging from my solar PV (the usual problem of trying the get free units and ending up importing when the sun goes in). So, I've spreadsheeted the consumption and generation profile over the year and I can see a considerable saving by going Economy7.

So, I spoke to my supplier this morning and it will cost me £57 to get a meter swap (no problem with that). I enquired whether this was a Smart Meter and was told, "No, but there is a Smart Meter replacement programme - do you want to be added to the list?" To cut a long story short, the Smart Meter will be free and can be sorted in a few weeks!

Does anyone know of any reason I should be wary of a Smart Meter with Solar PV?

groovyf

Out of interest, how much juice does the car suck when charging?