"Davey" wrote in message
...
It's been very hot here in the UK this past weekend and while lying awake
in
the sweltering heat, trying and failing to get to sleep, I was wondering
if
there was anything I could do to cool the house down. I started on how we
kept the house warm, and worked backwards. The obvious thing was the
central
heating: could I pump cold water around that? Well the rads. were already
cold, so that wasn't doing much. So why does the heating work? Because the
rads get a lot hotter than the surroundings. Could I pump very cold water
around the system? I couldn't see water even at 0 deg. having much effect,
so it would have to be well below 0 deg. to have any effect. The obvious
problem - you can't cool water below 0 deg. C! How could I stop it
freezing
up? Does the anti-corrosion additive have any anti-freeze properties?

The opposite to a radiator in this form would be a similar device mounted
close to the ceiling with something substantially colder pumped through it
(say a liquid with a low freezing point kept at -20C). Then convection
would do the opposite of what the radiator does in that the cool would
"fall" as opposed to the heat "rising". Problem is, the moisture in the air
would just ice up the metal and make a mess!! If you had a low (1C for
example) water based system, it would just condensate all over the place so
that's not a goer either!

Some old "air conditioning" systems do just use cold water pipes and a fan
to blow air over them, thus slightly cooling the air which is accelerated
around the room by the fan. A bit too subtle for my liking though! The
fact is, hot objects near floor level put high energy into the cold air
around them and send it with gusto up to the roof - this heats a room very
effectively if the volume of air is not too great. A cold system would be
too subtle without pumping the hot air past a refrigerant and blowing it out
aggressively through the room.

Trust me, the forced convection of an air conditioner will serve you better
;o)



a