Solar Power-is it worth it?

radcon

moonrakerz wrote: »

Those that "swear by it" usually have a vested interest - ie: they're selling them ! OR, they realise they have been conned and are too proud/embarrassed to admit it.

You seem to be forgetting the people that like to talk about them at dinner parties with their friends:p

Cardew - Thanks for the information. Although I would always have thought that the AGA feeds into a DHW tank through it's own coil, or into a thermal store if doing CH, again own coil - I've never come across the situation that you've described. On the look out now though - doesn't seem the best way of dealing with a problem, a towel rail maybe - but not two rads and two fin tube convectors.

Cardew

radcon wrote: »

You seem to be forgetting the people that like to talk about them at dinner parties with their friends:p

Cardew - Thanks for the information. Although I would always have thought that the AGA feeds into a DHW tank through it's own coil, or into a thermal store if doing CH, again own coil - I've never come across the situation that you've described. On the look out now though - doesn't seem the best way of dealing with a problem, a towel rail maybe - but not two rads and two fin tube convectors.

I have Gas CH and a Baxi open fire. Simple 'conventional' HW tank with the one coil.

The Baxi will feed to HW or CH in the same way as the boiler and a sensor will turn on the pump as required. The downside is that there is a gravity feed back to the baxi water jacket.

I could isolate Baxi with a valve, but of course I would then have the potential bomb as described earlier.

I did quite a bit of research on this.

To go the separate coil way and separate thermal store would create it's own problems I would have thought, also a tank with 3 coils, from boiler, solar, and Aga?

However you are quite correct that it is silly to have the set up as described by our friend with the amazing solar system. There is a 'work around' on this but with a solar system that produces such huge amounts of HW it wouldn't be needed.

Incidentally moonrakerz is absolutely correct about people being too embarrassed to admit that they have wasted their money**. Man's capacity for self delusion never ceases to amaze me; there are lots of people who post on here that are absolutely convinced that strapping a magnet(£29.99 a www.theresoneborneveryminute.com) to the fuel lines of a car or oil CH will reduce fuel consumption by 53.87%. The proof being they used 2 tanks of petrol last month and only one this month!

** I speak as someone who after a lot of research bought 2 Betamax VCRs and determined not to make the same mistake recently spent a lot of money on a HD DVD player!!

moonrakerz

Cardew wrote: »

** I speak as someone who after a lot of research bought 2 Betamax VCRs

Technically, you were spot on ! much better than VHS.

moo2moo

Against all the advice out there we DIY installed a 30 tube solar panel which supplies our extension with underfloor heating and a bathroom (adjacent to the tank) with hot water via a purpose built triple insulated thermal storage tank. From March to October all our showers are taken in the solar powered bathroom. The underfloor heating also warms the extension and also increases the background temperature of the adjacent rooms whilst disipating the surplus heat from the thermal store.

As a result our conventional LPG boiler (a completely separate system) heats hot water on demand for the kitchen during the summer for a stingy 30 minutes twice a day. During the winter this boiler runs for 30 minutes in a morning and evening for hot water and 1 hour in the evening for heat. We also fitted 3 multi fuel stoves but have sufficient free logs to run for the majority of the winter without needing to purchase fuel.

This works for us but it is a combination of all of the above which has reduced our fuel expenditure rather than a single thing. I have noticed a leap in the electricity bill of £20 per month as a result of running the pumps for the solar system.

Dedicated Pressure Systems have an online design your own thermal store thingie which allows you to concoct all sorts of combinations and get exactly what you need and then some. They weren't cheap but then again they weren't any where near as expensive as the major installers had lead us to believe. The service they provided was also superb. As for components and solar panels Navitron are extremely well priced (more so if you collect in person) and have a great forum for renewable energy sources.

The bit which surprises most people is the emergency heat dump. In case of the thermal store reaching too high a temperature (which has happened twice in 2 years) the surplus heat is dumped by means of the biggest radiator we could find which is attached to the outside of the house, painted with Hammerite paint to prolong its life.

We haven't added any additional insulation to the house as we doubled the recommended loft insulation 10 years back when we bought the place. It was built in the 1890s and has solid brick walls but they are 10" thick in places. It has 3 bedrooms, 1 with a multi-fuel burner and a very sprawly but semi-open plan layout where the downstairs is 50% bigger than the upstairs.

moonrakerz

I don't wish to be negative here, but I am not really sure if you are praising your system or criticising it.
The only hard "evidence" that you have provided about your system is that your electricity bill has risen by £20 a month.

When I read: "design your own thermal store thingie which allows you to concoct all sorts of combinations and get exactly what you need and then some." my credibility tends to switch off.

"The bit which surprises most people is the emergency heat dump" - it certainly does ! Please explain - have you discovered "cold nuclear fusion ?"

moo2moo

I don't wish to be negative here, but I am not really sure if you are praising your system or criticising it.The only hard "evidence" that you have provided about your system is that your electricity bill has risen by £20 a month.

I suppose its both. Its great in the summer useless in the winter. 2 years ago LPG was 23p per litre, now its just short of 50p per litre. If we hadn't made the changes that we have then based on the litreage delivered 2 years ago we would have been paying in the region of £4000 for LPG whereas last year we paid £650. How much of that is down to the solar? How much is down to the stoves and having a free local supply of logs? How much is due to the change in hours we work and the DDs both being at school full time?

When I read: "design your own thermal store thingie which allows you to concoct all sorts of combinations and get exactly what you need and then some." my credibility tends to switch off.

OK so your credibility switches off. It allowed me to purchase a 300l thermal store with 3 coils (in case I opt to hook in my back boiler or purchase a boiler which will accept pre-heated water), an immersion heater (in case water isn't hot enough or the boiler packs up) which was exactly what I wanted. I couldn't purchase this off the shelf. It enabled me to add on extras like the immersion heater and remove features I didn't need whilst knowing what the cost per component was.

"The bit which surprises most people is the emergency heat dump" - it certainly does ! Please explain - have you discovered "cold nuclear fusion ?"

No I haven't discovered cold nuclear fusion but I did discover that forgetting to increase the temperature of the underfloor heating after the winter allows the temperature within the thermal store to reach in excess of 95 degrees celcius after a few sunny days meaning either the water exits the taps via the very efficient heat exchanger within the tank at a temperature high enough to scald or that the tank temperature is rapidly reduced by disipating this excessive heat via the external radiator.

moonrakerz

moo2moo wrote: »

No I haven't discovered cold nuclear fusion but I did discover that forgetting to increase the temperature of the underfloor heating after the winter allows the temperature within the thermal store to reach in excess of 95 degrees celcius after a few sunny days meaning either the water exits the taps via the very efficient heat exchanger within the tank at a temperature high enough to scald or that the tank temperature is rapidly reduced by disipating this excessive heat via the external radiator.

Are you seriously telling me that you have to increase the underfloor heating temperature after the winter to prevent your "thermal store thingie" overheating and self destructing ?

If this is the case and you can prove it I'll go into business with you to sell this idea - I'll put my house on the market now to raise the funds

Now prove it - with facts and figures !

Cardew

Moo2Moo.
You have an interesting set up for heating, particularly with those of us with an interest in such matters.

However, having "3 multi fuel stoves but have sufficient free logs to run for the majority of the winter without needing to purchase fuel" must make the major contribution to reducing your running costs.

What is not clear from your posts is if any other source than solar is heating that thermal store ??? I assume there must be? I can't believe you are suggesting that in winter solar would heat water to above 95C even with underfloor heating dissapating heat.

The reason I ask is you are talking about the emergency heat dump(the purpose of which I understand) in winter? Yet you also say that the system(obviously the solar system??) is useless in winter. Those 2 statements seem to be at odds with each other.

moonrakerz, who also understands these things, has read your posts and understandably believes that you are suggesting solar alone is responsible, in winter, for 95c and a heat dump.

The problem with this sort of thread is it quickly gets away from the question the OP asked - is Solar cost effective; and basically it ain't!!

By solar most people mean either solar water for domestic hot water(NOT heating) or solar generation of electricity and I suggest most people's eyes 'glaze over' when it gets this complicated!!

The bottom line is that for most people with gas CH, you will be lucky to save £50 a year with solar water, and double that with oil. However if I had oil I would start to look very closely at Economy 7 electricity.

zarazara

i think installing a wood burning stove and putting pans of water on top to heat up for washing up and so on is the cheapest way forward. we hace just done this. now i wash up and do drinks with "free" hot water. by this i mean when its cold enough to light the fire for heat i place pans of cold water on top. they soon come to the boil. i trandsfer to washing up bowl or very large pan for storage to use later.

Foodjunkie_2

I work for a consultancy who designs M&E for new builds. Solar heating for hot water is a great idea and is catching on in this Country. (Check out the houses in and around the Med). The main drawback in this Country is that in the winter period, The water is just not hot enough, its tepid and requires a "boost" from the boiler or immersion heater.
Most systems come with a 10 year warranty, but the main hurdle is the cost of installation, you are talking up to 10K for an average house.
Interest from local Authoritys is high, as they are starting to install the solar water heating panels on school roofs and some prisons.

Perhaps over time as manufacturing costs reduce, and installation grants are made available form the government, it might catch on big time in the UK.
Untill then, just insulate the house the best you can, using what ever grants you can get your hands on.