On Fri, 24 Sep 2004 23:46:46 +0100,
wrote:



Back to the conservatory, is the aluminium structure a sound place to
dissipate any heat from the fittings? I believe -although they havent
actually said so yet - that this is what the conservatory supplier
may claim.

Brian



I don't think so.

The normal fitting position is in a plasterboard ceiling or similar
with space above and to the sides by some way - at least 150mm, if not
more. Cooling is going to therefore mainly be by air circulation
and convection. Since board is a reasonably good insulator, there
is no assumption of it conducting much heat.


If you consider and aluminium beam extrusion in the ridge, it probably
doesn't have any of those properties - probably much less depth and
much smaller space around the fitting. OK, it's aluminium and a
reasonable conductor, but the fitting will not normally have any
substantial amount of area in contact with it.
Perhaps the surface mount types would be a bit better from the heat
point of view, but 4 x 20W ones are not going to do much for you at
all.


..andy

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