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

legoman62

Just read this on another board re- the post "Intelligent solar immersion switch"

As the device measures grid export only what happens when the load is turned on? Say export was 3500W and set threshold is 3500W, so when load turns on export becomes only 500W. To stop it immediately turning the load off again it needs to know that the load consumes 3000W. Is there a control to set the load power?

To provide reasonably complete consumption of the spare power the switching needs to be frequent which must play havoc with the reliability of the element and relay. Never gets close to consumption of a proportional controller so their £100 pa claimed savings, especially on the Mark 1, is very unrealistic.

Not sure how accurate it is but at £600 it's gonna take a long time to get your money back.
I'm still using energsavingexp's idea (this site) and it's working a treat. Cheap to buy and put together(thanks to Phill). Gas usage for the last 3 months is virtual nil. Winter months will not be so good but, neither will the £600 one!

sly_dog_jonah

zeupater wrote: »

... I'd go even further ... your max £240/year on gas would equate to around 18.8kWh/day (240/0.035/365), so it does look a little high ....

I was basing that on the most 'expensive' summer month (when central heating is off). It also factoring in the standing charge. If I look at purely the kWh, then our usage is 13-14kWh/day in the summer months, which I extrapolate as being the constant cost of heating our water over the course of the year.

Haven't got time to digest the rest of your post right now...

zeupater

sly_dog_jonah wrote: »

I was basing that on the most 'expensive' summer month (when central heating is off). It also factoring in the standing charge. If I look at purely the kWh, then our usage is 13-14kWh/day in the summer months, which I extrapolate as being the constant cost of heating our water over the course of the year.

Haven't got time to digest the rest of your post right now...

Hi

Understood ... I was just confirming that the figures used to say that the gadget claims were high were relatively high in themselves ...

A couple of teenage girls in the household ? ...

Z

Cavemanu

SiEd wrote: »

I had 4KW PV system installed last November - just wondering what is the highest daily output anyones had this year - Mine is 25kwh although my system is split east/west so i don't expect to make the same as someone south facing array - but it would be nice to have an idea what others are generating - Thanks:)

hi there SiEd,

My highest figures (since Nov 2011 install on a 3.84 KW ESE 45 pitch roof with some shading in late afternoon) were:

• 26 KW on 27th and 22nd May
• 25 KW on 25th and 26th May
• 23 KW on 25th, 26th and 28th March

HTH

John_Pierpoint

Martyn1981 wrote: »

, What will happen if the govt and REC's finally decide on what a smart meter is, and begin to roll them out. I can't believe that the opportunity to measure export won't be included, given the countries decision to encourage many forms of household micro-generation.

There is certainly a swings and roundabouts element given that export is deemed at 50% but I believe on average is closer to 70%. I'm approaching 1yr anniversary and will have reduced demand by approx 1,000 units, from generation of approx 2,800. So export is around 65%, but only paid for 50%.

Also, I've said previously that I don't feel 3.2p is fair and that it should be 4.5p to match wholesale prices. I'd even go one step further and suggest the 'lack of' distribution losses (approx 10%) should bump the value of those units up to 5p. But, the FITs scheme is very generous, so as a package it all balances out and seems fair.

Mart.

My friend with the rotating backwards import meter is trying to reach a settlement with his electricity provider - The meter has gone so far backwards that he is feeling about 4 years younger. (*)
Needless to say his approach that they have paid him for 50% of his production and so he obviously ought not to be paid twice for this electricity is proving contentious.

What is source for the goose is source for the gander??

(*) ie time has more than stood still for nearly 3 years!

sly_dog_jonah

zeupater wrote: »

Hi

Understood ... I was just confirming that the figures used to say that the gadget claims were high were relatively high in themselves ...

A couple of teenage girls in the household ? ...

Z

Ah yes I misread your previous post. No teenagers yet, but a toddler who loves bathtime as part of her bedtime routine. Oh and we've another bun in the oven so give it a few years and I may be in the position you speculated, and I would be outnumbered in the house by girls...

Johuggs

Hi Gents,

Very interested to look through your discussions with regards to heating water from your PV systems and as you can image there are so many variables, from system size to orientation and water heating demands, you have made lots of points that I would like to respond to.

Please give me a call or visit our website at your earliest.

Fruit_and_Nut_Case

Johuggs :spam:

Hobbo2006

digitaltoast wrote: »

My mind is boggling here - our household of 3 manages just fine on one hour of 3kW immersion heating per day. At 6.5p/unit you'd get 2564 hours of heating for your £500; that's 7 years. Given that most new A rated washing machines and dishwashers are cold-fill to save wasted energy, it's not even like it'll be contributing to those appliances.

Immersun site says "We estimate a payback period of 3 years using immerSUN". The site is sadly lacking on any sort of helpful detail, so if anyone can fill in the gaps here, that'd be great. How does avoiding grid export help? What calculations are involved?

Given that you're least likely to be using or needing electricity when the sun is shining, what happens when you're into the 6th hour of heating? How big a tank would you need to hold all that? Has the 6 months of the year when the sun hardly shines been taken into account? It says "If the load from the house increases, eg. the washing machine is turned on, the immerSUN will reduce the amount sent to heat water to help you maintain independence from the grid."

Are immersion heaters even effective when used like that?

And £500 is a bit steep given that there are other products which do the same thing for about £30. http://www.reuk.co.uk/Water-Heating-with-Surplus-Solar-PV.htm

What's that funny smell? Is it snake oil? We need cardew or grahamc2003 to come and help with the numbers!

I think the numbers will be different for everyone. We have warm air central heating so our only method of heating hot water is via the immersion. I connected a monitor to it and it says that it uses 6-7 kWh's per day. So that's around £250 per year. With the cheaper version I showed in my original post I think I could have a payback period of under 2 years, which I think is worth it.

With a young family at home in the day the home made style versions don't cut the mustard as they don't take into consideration the electricity already being used.

Also, do I really want to start swapping immersion heaters or buying building site transformers to scale down the power? Probably not....

It's not going to be for everyone though I admit.

zeupater

Hobbo2006 wrote: »

I think the numbers will be different for everyone .....

... too right ...... by the time you've factored in a qualified electrician's hourly rate you could really count on doubling the base cost of the units ... reading instructions, cabling from the inverter and/or consumer unit, installation, testing, provision of relevant paperwork, drinking half a dozen mugs of tea, etc ....

Z