Storage Heaters - Would charging them from a Solar System make sense?

blankscreen

Much appreciated again Neil,

Sales reps assured me of 4kw for 4 hours of daylight as being a minimum, even if covered with snow (which istill doubt), but there is no way i could independently varify this with pratical experience before buying, by which time it woukd be to late.

Powering Storage heaters tbh for me are not a big deal, i try to maximise what i can get out of any item i buy and it firms oart if the pro's and Cons of decissions.

We have gas heating via a condensing boiler, with all electric cooking. one  bright rep suggested fitting a tank for hot water using the tube type panels to heat it in addition to the 4kw . He was doing so well until i pointed out the washing machine and dish washer were cold fill only, and we had removed our bath some years ago to make a utility room, as we both prefer showering via a power shower. which is instant while saves on water charges so the only use for solar hot water was at the kitchen and 2 hand sinks.

i sell equipment for a living, but still felt gloriously evil watching the obvious deflation spread across his face .

Alan

neilball

Panels that generate when covered in snow! Next he'll be telling you that they work at night too

blankscreen

lol! i suggested illuminating them at night from 12 v flood leds using car batts that are charged durung the day,

caused yje longest scratched chin moment in history .

neilball

I'm not sure if there are many people still following this, but I thought I'd add some more results from some real systems. I upload my data to a monitoring site with many others from the UK and around the world. Over the last week or two is has been mostly cloudy over most of the UK, and I've been looking at the output from the 465 members across the UK who are regularly uploading their info. On many overcast days there are less than 10 sites that achieve over 2kWh of generation, and more than half of these of have 8kW-10kW arrays, so significantly larger than most residential arrays. Around another 35 managed somewhere between 1-2kWh, and all rest (over 400 sites) generated under 1kWh. The figures also provide the peak instantaneous output for each day, and none achieved higher than 1.8kW, even with 8kW of panels in this case

So this reinforces the point that in winter you cannot rely on any really useful output to run heating-type loads regardless of where you are in the UK. Any sales person telling you otherwise is at best uninformed, and at worst just outright lying to try and close a sale.

blankscreen

I'm still watching the thread if just out of curiosity, even after i came close, i'm personally not going to install a system in the forseable future prefering to keep my capitol in my wallet.

20 years time i'll be oaying through the nose fir enegy, but then i'll flog the house abd get me an electric scooter, a flat in Spains Costa Del Sol - and a hot Danish house keeper .

Alan

Solarphil

Hi Neil, Yep PV is not really best designed for supplying heat full stop, however there is one case where it works and thats if you pair a very large system with a small load. So say putting a 50kW or even bigger say upto 250kW onto a farm house. We've got a couple of sites where we are doing just this and the forecasts are that we will reduce the site loads by 80% or so. However you will need a 3 phase supply and a large transformer to go with systems of that size. One thing that will change over time is that systems will get larger and excess production will be dumped into batteries , this should become a reality in the next 2 to 3 years once the new Tesla Gigafactory battery plant comes online around 2017.

Solarphil

@blankscreen rather than trying to dump the power into the heaters which you will be able to do a bit if they are charging through the day you would be better placed to dump the power into the water tank as hot water (its a pretty good way to store power). The heat for water is required pretty much through all the year where as heat for warmth is pretty much only really required in months where solar isn't producing much.

A good way of doing this is to use a diverter such as PV Water Heating, Solar Hot Water Switch and Controller Supplier in Lincolnshire, UK  | immerSUN this has a CT clamp on the incoming supply and watches for when export is occurring and switches on the immersion heater in your water tank. This can soak up a lot of excess generation as it can be paired to a 3kW heater which will pretty much use all the power in the centre of the day. This sort of device has a very short payback period as your utilising power that you would have been given away for free and saving power to heat the water at 14p/kWh on electric or about 5p/kWhth for gas.

I note from your other posts that wondered about payback times a 4kW system at £6k which is a mid range price should deliver a return of about £750/yr if you don't use the power or upto £1050 if you do so payback is 6 to 8 years dependent on your location and use patterns. Thats a 12 to 17% return, better than money in the bank!

Solarphil

It is possible to get a little bit of output if you've got a very clear day and a thin layer of snow but in general they're talking out the posterior!

Solarphil

A
Actually that will work! Have a friend thats done this but... 1kw of energy into the flood light then panel is 15% efficient so only 150w comes out the back end... its a good way to burn 850w of electric!

Solarphil

@blankscreen @neilball best advice for heat is pair solar PV system for electric and a biomass boiler for heat that way you can benefit from Renewable Heat Incentive (feed in tariff for heat) if your on LPG or Oil its a no brainer the payback is better than PV