Ian Stirling wrote:
Steve Firth wrote:
Ian Stirling wrote:
snip

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

it does seem optimistic, I wonder if Steve meant the panel was only
1m^2 but had a large external concentrator of some sort?


NT