On May 28, 11:01*am, (Alan Braggins)
wrote:
In article ,www.GymRatZ.co.ukwrote:
On 25/05/2012 06:42, harry wrote:

Such a device is pointless. *You don't need any house heating when the
sun is shining. Heat collected in Winter is minimal in the UK climate.

But if the cooling of the PV increases their output and can provide a
20+ (?) degree temperature rise to pre-heat mains cold water before it
goes through the combi. that could in it's self could make quite a
reduction on gas consumption during summer months for DHW would it not?

You can buy hybrid thermal-PV systems, but "does it work" and "does it
make economic sense" are different questions.

http://www.renewableenergyworld.com/...olar_collector

(For even more efficiency, and even higher capital cost, use the electricity
to run a heat pump so the working fluid in the collectors is chilled below
ambient going in, and you get water output at full DHW temperature.
I'm not aware of anyone doing this, nor suggesting you can cover the additional
cost of the heat pump by doing so :-) )

I was told it can be achieved by runiing two heat pumps "in series"
Dunno anyone who has done it though.

As per previous post, the way forward seems to be CO2 refrigerant air
source heat pumps for the future.
http://uk.sanyo.com/aircon/Products/.../Introduction/