On Wed, 20 Aug 2008 11:46:46 GMT
[email protected] (Robert Scott) wrote:

On Tue, 19 Aug 2008 21:16:54 +0100, Steve O'Hara-Smith
wrote:

It does strike me that it may well be reasonable to use the loft
as
a solar collector here.

Where is "here" exactly?

Western Ireland.

OK, so if ice dams and air conditioning costs are not an issue with you,
then look at the cost/benefit ratio. You can't run potable water
directly through an automotive radiator, so you are probably stuck with a
large number of home heating-type fin tubes.

Or a heat exchanger between water running through a car radiator
and potable water, perhaps a second coil in the tank.

On the other hand, if you installed a real solar collector outside the
roof, a much smaller unit could deliver more heat, and it could deliver
that heat year-round, instead of just in the summer, as with your
in-attic collector.

I was wondering about cheaply glazing the roof.

Most of the heat the falls on your roof gets
conducted away by the wind. What remains has to travel through the
insulating properties of the wood sheathing.

What wood sheathing ? Roofs round here are tiles on felt on wood
frame.

Then it has to transfer to
air without the benefit of active circulation, then it has to transfer
again into your "collector". A collector on the roof prevents much of
the wind-conducted losses and avoids two air-to-solid heat transfers.
About the only benefit to the inside collector, as was pointed out by
earlier posters in this thread, would be to disguise the collector for
appearance sake.

It may well not work out as feasible - but it's an interesting
possibility to explore a bit.

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