On one of my regular walking routes I pass a large 1950s detached house which is being comprehensively gutted and modernised.
It's close to completion and I recently noticed with surprise that since I last passed that way it has acquired an array of those black tubular solar water heating tubes on the south facing pitch of the main roof.
I was initially surprised as this is clearly a high end modernisation and I associate those black painted tubes as a basic obsolete technology from 20 odd years ago. But then on reflection I wondered if they could be experiencing a revival as a roof mounted solar source heat pump.
Was wondering if anyone knows if this is a thing? I suppose it would come down to a cost/benefit analysis comparing occupying that space with solar water tubes serving a heat pump with solar panels generating elec instead.
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Solar water heating
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- 2 Lemon pips
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Re: Solar water heating
There is a realisation that for domestic water heating, collecting solar heat can be more efficient than using solar PV panels (which are only about 21% efficient). Heating domestic hot water tends to benefit from higher temperatures than space heating, especially if space heating is being done with a heat pump, so solar heating can make make a very good complement to a heat pump as it can produce high temperatures even in winter.
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- Lemon Half
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Re: Solar water heating
IIRC solar is far better at heating water than generating leccy. But the leccy attracts a FIT which the water heating doesn't, and in addition it is maintenance-free, which a water-filled system isn't. And finally the water system is desperately season-dependant. Even more so than the PE cells.
Solar water is probably far 'better' for the environment than PE, the benefits of which are distorted by guvvermint subsidies.
Solar water is probably far 'better' for the environment than PE, the benefits of which are distorted by guvvermint subsidies.
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- Lemon Quarter
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Re: Solar water heating
Mike4 wrote:IIRC solar is far better at heating water than generating leccy. But the leccy attracts a FIT which the water heating doesn't, and in addition it is maintenance-free, which a water-filled system isn't. And finally the water system is desperately season-dependant. Even more so than the PE cells.
Solar water is probably far 'better' for the environment than PE, the benefits of which are distorted by guvvermint subsidies.
I know people with both who rave about the solar water heating, even in winter it does a good job of providing a baseline of hot water. I'm pretty sure you need a 'special' type of cylinder though - most gas boiler cyls have one heating coil and AIUI these need a twin coil system, so installing during a refurb makes sense. Actually that reminds me, the plumber is coming today to talk about a new cyl, and the roofer hasn't tiled that end yet.......
With solar, at the 15p/kWh we get for export it is borderline in cost beween using gas or electric to heat the water.
The FIT and subsidies went several years ago
Paul
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Re: Solar water heating
DrFfybes wrote:The FIT and subsidies went several years ago
Paul
For new installations, yes, but I carry on getting the FIT until 2036, RPI indexed. Crazy scheme. They now pay me about 71p per kWh, and I get to use the electricity. I almost feel guilty.
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- Lemon Half
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Re: Solar water heating
Surely even with new installations they still pay you for energy supplied into the grid? That's what I meant by the feed-in tariff.
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Re: Solar water heating
Mike4 wrote:Surely even with new installations they still pay you for energy supplied into the grid? That's what I meant by the feed-in tariff.
Yes, however that is down to your energy supplier and there are no govt subsidies.
AIUI the FIT is/was a payment for what you generated, not what surplus energy you exported. So if you used it all in the house to heat water or charge a BEV you still got paid for generating it.
Baskerville Hall in Clyro has a pellet burning heating system on a FIT. It is stiflingly hot there as apparently they make money for every kg of pellet they burn, AND get free heating.
Paul
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Re: Solar water heating
Mike4 wrote:Surely even with new installations they still pay you for energy supplied into the grid? That's what I meant by the feed-in tariff.
Yes, it is called SEG - Smart Export Guarantee. The best rates vary quite a bit. Octopus currently offer 15p per kWh for exported solar.
Note, your SEG account does not have to be with your electricity supplier, so you can shop around.
FD
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