wrote
Rod Speed wrote
wrote
Dennis@home wrote
wrote
Interesting feedback thanks. Obviously
not a good idea is the general consensus.
Just as a matter if interest I thought Id run these figures
by and see if I can get a clearer picture... My electric
storage heater uses 12kwh a night on cheap rate night
tariff. (Thats 85 p/night) That gets it nice and hot.
Im trying to calculate how many panels would give
me the equivelent of 12kwh mains a day...so...
In winter a 2kW array will give you less than 1 kWhr
if its cloudy and about 1.5 kWhr if its sunny.
In summer its about 2kWhr and 10kWhr for the same array.
The same area of thermal panels will
give you about four/five times as much.
With solar thermal you get a lower grade heat from flat panels
than from evacuated tubes. The same amount of energy if the
store is cold enough to make use of the lower grade.
From a cot point of view you should have solar PV fitted as
the fits will pay fo it and return a profit. Then fit an immersun
or similar to heat during the day when power is available.
Flat panel solarthermal yield much more than tubes per area and per
pound when heating cold water (and only when heating cold water).
Not sure that last bit in brackets is true.
I guess I should be more precise and say below the temp
where the yield of both technologies become equal,
which is between cold & the wanted hot water temp.
Why isnt it just as true with a solar air heater ?
they dont heat hot air, plus they generally use dfferent designs.
Regardless of that, tubes just don't work as well with solar air heaters.