"IMM" wrote in message
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"RichardS" noaccess@invalid wrote in message
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"IMM" wrote in message
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I could use 400 squ foot of flat plate collector on the roof,
twice
the
area, and produce the same volume of solar hot water as the
Thermomax
solar
collectors which takes up half as much square footage.

The area is "very" important in this instant. Is that clear?

Yes, but efficiency is independent of that IMM.

Thats tantamount to saying a 5oKw boiler is twice as efficient as a
25Jw
one.

It is not. Solar collectors produce hot water. Some produce more
than
others for the same area, hence more efficient for a given area.

No.

Efficiency is the ratio of converted power out to power in .

The area doesn't come into it.

In this case it does. Area is the most important factor as it is limited
on
a roof. Solar panel X can be more efficient (ratio of converted power
out
to power in) than panel Y. But panel X may take up four times the area of
panel Y. It means eff all if the area is not taken into account. For a
given area which is the most efficient? Area, area, area.

If the efficiency of a panel is 60% per square ft then, on the assumption
that you understand what physical dimensions and units are, the efficiency
of 1 sq.ft is 60%, the efficiency of 2 sq.ft is 120% and so on. I
suppose you realise now that you have hit on a method of producing perpetual
motion.

Let me ask a final question:

Given that, as you say, the efficiency is 60% per sq foot, what will the
efficiency of a set of panels covering 200 sq. ft be?
Note, I am asking for the efficiency of the whole set, not the "efficiency
per sq.ft", as you put it.

I take it that we agree that the efficiency is the ratio between the power
in the insolation and the power delivered to the heating system

Franz.