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Author: Subject: Solar Hot Water
onzarob

posted on 23/2/08 at 08:02 PM Reply With Quote
Can't you build a locost version using black alcathyne pipe and a central heating pump!!!

IIRC They can't put a sign up for longer than 8 weeks past the completion date as it then requires planning consent

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JoelP

posted on 23/2/08 at 08:52 PM Reply With Quote
The one on my mind at the min is preheating your water before it enters the shower, either from a heat exchanger in the waste pipe or maybe solar to add a few degrees to it. Wouldnt save money but would make the shower flow a bit better!

Im sure there is some merit to simple log fires, you can find free fuel and with a bit of bodging get warm water too.

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zilspeed

posted on 23/2/08 at 09:04 PM Reply With Quote
And if you use damp logs with a bit of moss on them , it smells fantastic as well.






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paulf

posted on 23/2/08 at 09:14 PM Reply With Quote
There was a programme on Tv last year , I think it was rogue traders that looked into solar heating and found lots of companys with exagerated claims.
To heat your tank that quickly would requrire a few kws of heat and its not likely to come from a solar panel.
I have a south facing end wall to my house and a flat garage roof and looked into it but it didnt seem worth all the effort, although having seen my last gas and electric bill may think about it again, or better still look into a simple combined heat and power unit if i can find a suitable generator cheap.
Paul.
quote:
Originally posted by smart51
The evacuated tubes don't need direct sunlight, just light. so they provide most of your hot water in the winter and all of it in the summer. Work out how much you spend of Gas and work out your payback period.

I'm told that a solar system adds 9 - 10% to your house value, not that we're planning to move, but if you're a light gas user payback may be quicker if you move house.

I know that salesmen are full of it but one thing that he said was all bull. He reckoned that a full tank of 95° hot water took 1 hour on a cloudy winter day and 20 minutes on a sunny summer day. From his literature and common sense, his solar panel will heat the tank by 10°C per hour in full sun and maybe 7° when cloudy.

[Edited on 23-2-2008 by smart51]

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jono_misfit

posted on 23/2/08 at 09:20 PM Reply With Quote
The systems ive seen have a separate circuit for the heated water with a heat exchanger to transfer to the boiler feed. Im guessing legionnaire's disease is less of an issue in these cases.

If your interested in a system, read up on how they work. Look at available systems and install it yourself. Makes the payback more attractive.

I had a lecture at uni a couple of weeks back about the systems from the UK's foremost authority (alegedly) on them. He was saying some interesting things and how its quite beneficial even with homemade systems. Apparently Scotlands one of the most optimal places to have solar heating in Europe.

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SeaBass

posted on 23/2/08 at 09:24 PM Reply With Quote
We have a solar water heating system intalled in our house. It was installed by the previous owners. There are four panels on the roof (the technology of which I have not explored). There is a controller which switches on a small electric pump when the panel temperature is higher than the temperature in the tank by a certain amount. We have a much larger than normal dual coil tank installed.

We do not get any gains during winter conditions because of our location and daylight hours therefore revert to gas. From mid March onwards all of our water heating is provided from the solar panels. From May to August heated Water temperatures are from 65-80 degrees.

We had little or no idea about the system when we purchase the property but with increasing energy prices it has been a godsend.

Cheers
James






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wicket

posted on 23/2/08 at 11:36 PM Reply With Quote
Here's a DIY system

http://www.builditsolar.com/Projects/WaterHeating/MSClosedLoop.pdf

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turbodisplay

posted on 23/2/08 at 11:56 PM Reply With Quote
I was looking at making my own system for a holiday home, as the choice is freezing cold water all the time or solar.
It is mainly pipes painted black, glass to insulate/let ir energy in and a black back panel to convert the ir to a longer wavelength so the heat does not radiate back through the glass.

Darren

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Bob C

posted on 24/2/08 at 01:07 AM Reply With Quote
Solar energy arriving at earth is about 1kW/sq m so yes, a few kilowatts IS available. Complete DIY systems are often something like a black painted radiator in an insulated box with a glass lid. These are a bit inconvenient to plumb & losses are high so they don't work so well in winter. The vacuum flask ones are less lossy & use heat pipes to carry the heat to a manifold at a single end, so basically you have to buy 'em. They're the "few hundred quid" option I talked about above. You can expect such a system to raise the water temp in the cylinder by 10K in winter - not enough to use directly but still it's 10K you DON'T have to find by burning gas.
I agree the "green bandwagon" firms are disgraceful in the way they make preposterous claims to dupe well meaning folk. I've heard heat pumps described as "free heating" - when best case it's 1/3 cost electric heating AFTER a massive installation cost.
The most disgraceful thing I'd heard for a while was on the news this morning - some old guy had trouble with his boiler last week when it was freezing, & he was on the maintenance deal with british gas. Because of a small leak they condemned his boiler, locked it off & made him stump up 7grand to fix it. I was outraged, they might as well have put a gun to his head. He's since got competitive quotes averaging 2 grand..

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zilspeed

posted on 24/2/08 at 09:33 AM Reply With Quote
The gas companies are famous for their prices being outrageous.

In my line of work we have to ask people to get two quotes for their works. For heating, most used to get Scottish gas out to quote but they (Scottish Gas) are refusing to do it now as they know that they will be between two and three times the cost of everyone else.






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froggy

posted on 24/2/08 at 11:06 AM Reply With Quote
another alternative is dig a hole where your gas comes in ( a lot are plastic pipes now) put a tee piece in and run that into your house past the meter for instant half price or even free gas,going rate is about £500 .electric is more expensive as you need a switch either in the meter box or inside before the consumer board.i have NOT done this for the last five years with no problems
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SeaBass

posted on 25/2/08 at 07:32 PM Reply With Quote
^^^^

Eh?






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