jacko
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| posted on 22/2/10 at 09:11 PM |
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Solar collectors / panels
Hi all anyone using them to heat water ?
We are having a new roof fitted this year. After that solar panels but i would like to know how good they are with living in this county, are they
worth fitting for the cost?
Also does it matter which direction they face ? my roof faces one side east the other side west
Jacko
[Edited on 22/2/10 by jacko]
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liam.mccaffrey
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| posted on 22/2/10 at 09:33 PM |
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if you want to heat water you need solar collectors which are different to photo voltaic (electric solar panels)
They will work in this country, I am building locost ones facing south.
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iank
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| posted on 22/2/10 at 09:38 PM |
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quote:
Originally posted by jacko
Also does it matter which direction they face ? my roof faces one side east the other side west
Jacko
I'd be putting them on the west side as then you'll have the warm water in the evening rather than lunchtime. South would obviously be
better, but you knew that already 
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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jacko
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| posted on 22/2/10 at 09:38 PM |
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Thats what i meant 
Thanks
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jacko
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| posted on 22/2/10 at 09:51 PM |
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quote:
Originally posted by liam.mccaffrey
if you want to heat water you need solar collectors which are different to photo voltaic (electric solar panels)
They will work in this country, I am building locost ones facing south.
If you are making locost ones have you any planes photos to look at please
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twybrow
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| posted on 22/2/10 at 10:42 PM |
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Locost version is a load of radiators, painted black, and stuck on your roof with (or even without) a pump. They made a 'locost' version
on "It's not easy being green" shown on BBC2 a while back. They soldered together a lattice of copper pipe/fittings, and painted it
black. They then put that in a white box with a perspex front. It seemed to do the job!
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smart51
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| posted on 22/2/10 at 10:51 PM |
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They certainly work but not every day of the year. As an assistant to a conventional system, they'll reduce the energy you use. Installation
when having a roof fitted is the best time. I had a couple of quotes a few years ago for a retrofit and they were having a laugh with the price. A
DIY install will pay for itself, even if you buy good kit.
As for angle, they have to point at the sun. They pretty much have to be south facing and at a good angle of inclination. East or West and
you're only going to get a small fraction of the energy.
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NigeEss
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| posted on 22/2/10 at 10:56 PM |
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Modern tubes are like "thermos" flasks with the black heating tube inside a vacuum.
Heating is by radiation and the outside temp is largely irrelevant. Thus they work in the winter.
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spewing
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| posted on 22/2/10 at 11:02 PM |
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Theres a program available that is used by a lot of the companies selling panels that you select your location, Panell make and orientation and other
variables and based on weather statistics tells you what sort of performance you will get (sorry i dont have a copy)
Best case senario for the UK despite what some people will try and tell you is saving 55 to 60% of the energy used to heat hot water (not central
heating) unless you can afford to plaster your roof in panells, feed them into an acumulator and the run a low temperature heating system such as
underfloor heating but that will cost big money to retro fit.
If your re roofing and you decide to go with them its worth looking at built in panels as they look a lot better.
Kev
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SeaBass
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| posted on 23/2/10 at 08:36 AM |
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We have four panels on the south facing roof of our house. They were installed by the previous owners of the property who paid a fair bit for them.
From about the end of March until about September we do not use any other energy than running the circulation pump to create hot water. A controller
determines when the pump should run etc. The panels will fill a tank full of water at about 70 degrees. Hotter than provided by the central heating.
I had no idea what they'd be like but they have saved us a lot of money. We've recently had the system serviced, cleaned and refilled by
the installer which was surprisingly cheap and has restored efficiency.
Cheers
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JeffHs
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| posted on 23/2/10 at 09:24 AM |
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Look at CAT the Centre for Alternative Technology site. They have loads of plans and info some cheap and downloadable.
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coozer
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| posted on 23/2/10 at 09:48 AM |
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They will work down there marra, they work here in Co. Durham, theres a house a few miles from me got them on the front and side (south and west ish)
with a sign up telling everyone what they are and the benefits.
1972 V8 Jago
1980 Z750
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craig1410
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| posted on 23/2/10 at 01:03 PM |
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I would expect that the type surrounded by vacuum would be essential otherwise you would need to pump warm water around them in the evening to avoid
them freezing up and bursting!
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smart51
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| posted on 23/2/10 at 02:38 PM |
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quote:
Originally posted by craig1410
I would expect that the type surrounded by vacuum would be essential otherwise you would need to pump warm water around them in the evening to avoid
them freezing up and bursting!
Not really. You don't pump pure water through them, but a mixture of water and antifreeze, just like your car. The mixture circulates through
the panels and through a second coil in your hot water tank.
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craig1410
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| posted on 23/2/10 at 05:21 PM |
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quote:
Originally posted by smart51
quote:
Originally posted by craig1410
I would expect that the type surrounded by vacuum would be essential otherwise you would need to pump warm water around them in the evening to avoid
them freezing up and bursting!
Not really. You don't pump pure water through them, but a mixture of water and antifreeze, just like your car. The mixture circulates through
the panels and through a second coil in your hot water tank.
Fair enough but surely you would also want to benefit from the radiated heat without losing out to conducted heat. It could easily be below freezing
air temp but still with considerable radiated heat. That's why it often feels "nice in the sun" but cold in the shade.
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smart51
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| posted on 24/2/10 at 04:06 PM |
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I'm not sure what you're saying but yes, you do want to get something on a sunny but cold day.
Evacuated tube collectors are better at this but flat plate collectors can do something.
Your flat plate should be a matt black colour to best absorb the incoming light. It will be fitted in an airtight box that is insulated underneath
and to the sides. It will also have a transparent cover over the top.
Incoming sun light hits the black surface, heating it up. Some of the heat will be lost to the air next to the panel but the glazing will stop that
warm air escaping. The glass will conduct some of that heat away but you've contained a lot of it.
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