"There are some water cooled panels available, but costs make them uneconomic for now."
Couldn't you just use that warm water and so make it economic? Are there any combined systems that try this?
Couldn't you just use that warm water and so make it economic? Are there any combined systems that try this?
Unless your system can regularly heat up to >60C to kill legionella then it will need external heating.
Secondly, when the external temperatures are high there's very little need for warm water. Perhaps a few dozen litres for washing. No one is taking a hot bath on a summer's day!
If you have the space, you can store the hot water underground and then pump it back up in winter for heating. But that's expensive.
Depends on your other systems. Dishwater wants hot water(but usually has no input for hot water), washing machine(some do). And if you have a house with 4+ people who like to shower a lot .. it adds up very quickly. And yes, heating. Now are already the days (in europe), with cold nights and mild but sunny days.
So .. it makes sense in theory, but not so easy to economically make use of as of now.
Like if you need enough water for shower you might just need heat of like... one or two solar panel sized heaters, anything extra means water will be permanently hot and so any benefits from cooling would be minimal unless you had some heat dump to pump the excess heat out. So more cost
There is probably some use for heating house in the spring/autumn, but system that can put the heat from panels either to heat the water or heat the house is additional extra complexity and cost.
- water for heating your home is in a closed loop, and you wouldn't want to add this cooling to that closed loop as it would heat up your solar panels on cold days
- water for drinking/washing comes from the same cold feed, and you don't want to heat that up as you can't get cold water then
- bisecting the water supply into hot taps and cold taps, and running the hot one under the PV cells could work, but it would only flow the water when something is pulling water, e.g. running a tap, which might be a hindrance to cooling
The heat collectors are vacuum insulated, so provided with enough solar radiation, they will work even when it's very cold outside. These systems work okay for example here in Finland. Of course it's a limiting factor that you normally need the heating most when the solar radiation is at the minimum. If you've got a swimming pool or some other use for the hot water during the summer, it's a good deal.
I'm not sure how this would work in a modern UK heating system - there is no warm water accumulator to my knowledge.
> 59% of dwellings in 2019 used their central heating system to provide hot water without a separate cylinder. Around a third (32%) used their central heating system to provide hot water through a separate hot water cylinder, 7% had a hot water cylinder and immersion heater as the primary means of water heating and less than two percent had an instantaneous water heater or dedicated boiler (1% and 0.2%, respectively)
So about 40% have hot water tanks, though I guess the number is falling.