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"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 ther

"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?

edent 3y ago
You can, but the problem is that warm water isn't that useful. 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.
- hutzlibu 3y ago
  "You can, but the problem is that warm water isn't that useful." 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.
robertlagrant 3y ago
I'm not sure where you could use it. At least in the UK: - 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
- Maakuth 3y ago
  There are solutions in the market for this. The heat recovery system is filled with glycol solution, which means it doesn't freeze over even if left unpowered during sub-zero outside temperature. Then there's a temperature sensor and a control unit that only runs the pump when the fluid in the panels is warmer than the warm water accumulator of the home heating system. 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.
  - robertlagrant 3y ago
    > the warm water accumulator of the home heating system I'm not sure how this would work in a modern UK heating system - there is no warm water accumulator to my knowledge.
    - Maakuth 3y ago
      I suppose a modern gas or oil burner doesn't need one. But this sort of solar based heater as well as ground-source heat pumps typically would need it. They are not very expensive however, as they are just heat-insulated tanks of water. Of course space requirements and such might rule out adding one in many cases.
      - robertlagrant 3y ago
        I think it's more - how do you hook it up with the rest of your water?
        Maakuth 3y ago
        The gas boiler has a small tank where the radiator circuit's water is heated. Warm water accumulator is analogous to making this tank larger. The radiator connections would be moved to the big tank and the boiler would be made to warm that tank. Perhaps typical combination boiler isn't optimal for this setup, so incorporating other heat sources might be best timed when the boiler is due for replacement anyway.
senectus1 3y ago
its not the running of them thats uneconomical, is the added infrastructure and component cost.
adql 3y ago
There are but you just won't be able to use all that water if you have more than a few panels. 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.

"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?

edent 3y ago

You can, but the problem is that warm water isn't that useful. 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.

hutzlibu 3y ago
"You can, but the problem is that warm water isn't that useful." 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.

robertlagrant 3y ago

I'm not sure where you could use it. At least in the UK: - 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

Maakuth 3y ago
There are solutions in the market for this. The heat recovery system is filled with glycol solution, which means it doesn't freeze over even if left unpowered during sub-zero outside temperature. Then there's a temperature sensor and a control unit that only runs the pump when the fluid in the panels is warmer than the warm water accumulator of the home heating system. 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.
- robertlagrant 3y ago
  > the warm water accumulator of the home heating system I'm not sure how this would work in a modern UK heating system - there is no warm water accumulator to my knowledge.
  - Maakuth 3y ago
    I suppose a modern gas or oil burner doesn't need one. But this sort of solar based heater as well as ground-source heat pumps typically would need it. They are not very expensive however, as they are just heat-insulated tanks of water. Of course space requirements and such might rule out adding one in many cases.
    - robertlagrant 3y ago
      I think it's more - how do you hook it up with the rest of your water?
      - Maakuth 3y ago
        The gas boiler has a small tank where the radiator circuit's water is heated. Warm water accumulator is analogous to making this tank larger. The radiator connections would be moved to the big tank and the boiler would be made to warm that tank. Perhaps typical combination boiler isn't optimal for this setup, so incorporating other heat sources might be best timed when the boiler is due for replacement anyway.

senectus1 3y ago

its not the running of them thats uneconomical, is the added infrastructure and component cost.

adql 3y ago

There are but you just won't be able to use all that water if you have more than a few panels. 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.