Steve Firth wrote:
Ian Stirling wrote:
Steve Firth wrote:
Ian Stirling wrote:
snip
Also wondering what the possible ratio of a fan assisted panels
radiator/panel size is.
Hmm sounds overkill to me. A one metre square panel that I made myself
works well enough to give 200 litres plus of water at 80C from around
five hours in the sun. Traditional construction of a single panel steel
radiator with an aluminium frame, polyurethane insulation, single glazed
in 4mm glass.

That does seem rather unlikely, unless you're starting from something
quite warm.

5 hours * 1.3Kw/m^2 (sunlight falling on top of atmosphere) = 23.4MJ

200l of water has 4400J/K/Kg * 200Kg = 880KJ/K.
23.4/0.88 = 26.6K temperature rise.

I'd be astonished if you got a real 20C rise out of it.

Your numbers do however work out perfectly for a panel of reasonable
construction on mercury

Gee thanks. I'd suggest that the water in the cylinder is stratified.
Your figure of 23.4 MJ on the atmosphere is higher than the actual
insolation with is about 24MJ/8H according to the local Uni.

snip

Yeah - I was mainly doing the numbers as they seemed surprisingly good,
and diddn't accord with what I remembered.


I presume it's possible that the cylinder remains hot over night, it's
difficult to eyeball a cylinder and know how much heat is in it.

But, if in practice it gives you enough hot water