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Posted by Noon-Air on August 7, 2008, 7:28 pm
> Hi:
>
> Please don't get upset at me. I posted something similar recently but
> it didn't describe it properly.
>
> I thinking of a cooling mechanism for houses and building in which the
> cooling -- in the direct sense -- involves only radiation and no
> convection at all. Sorta like a radiant-stove-top in reverse.
> Indirectly, however, some amount of convection and conduction will be
> needed [liquid helium, cold metals]. The cooling panel is the ceiling
> and cools objects below it.
>
> My visualization is that the radiant cooling panel contain extremely
> cold metallic coils [cooled by liquid helium to almost absolute zero],
> this would probably be deepest part of the panel.
>
> http://en.wikipedia.org/wiki/Liquid_helium
>
> Here, another question arises. Which is better to use -- Helium-3 or
> Helium-4? Which one would have a stronger cooling effect if both were
> at the same temperature?
>
> The radiant cooling panel is the ceiling. It has 3 layers.
>
> Layer 1: a material that allows heat radiation to pass through but is
> a very poor conductor of heat
> Layer 2: the same material found on the very top of radiant stove
> tops
> Layer 3: this is the deepest part containing the cool metallic coils.
> Inside these coils are where the liquid helium would be flowing
> through]
>
> Layers 2 & 3 don't have any air molecules around them. The cold metal
> coils are in a vacuum so they are not exposed to any air that would
> solidify/liquefy. This means the space between layer 1 & 2 is also a
> vacuum free of air.
>
> There is dehumidification which is separate from the cooling.
>
> Dehumidification is done by air processing devices on walls -- left,
> right, back, front. These walls give out and take in air. There is
> both re-circulation and fresh air. For fresh air, all vapors molecules
> are let into the room -- excluding H20, CO2, gases with odors, toxic
> vapors [such as CO], dust, irritating vapors, smoke or allergens. For
> re-circulation, air in the room is sucked, cleaned [i.e. H20, CO2,
> toxic vapors [such as CO], dust, irritating vapors, smoke and
> allergens are removed] and then blown back into the room. In either
> case, the amount of air-molecules-per-second-per-square-meter that is
> sucked out of the room is the same is the amount of air-molecules-per-
> second-per-square-meter the is blown into the room -- and visa versa.
> Hence, the subject in the room doesn't feel any sucking or blowing.
>
> The result is that the room now contains only N2 and O2 -- if you
> exclude the CO2 and H2O-vapor emitted from the living subject[s]. The
> N2 and O2 are kept at no less than least 70 degress Fahrenheit -- via
> convection heating if the ambient temperature is less than 70 F -- to
> prevent them from liquefying or solidifying. I know it's ironic that
> the air would have to be heated in order to assist in preventing the
> radiant cooler from failing. Still interesting, though.
>
> Yes, heat absorbed into the radiant cooling panels is carried off
> using convection -- but this is not what the subject inside the room
> feels. The direct cooling effect on anything/anyone inside the room is
> radiant.
>
> Can anyone suggest a better manner for direct radiant cooling? If so,
> please explain
>
> By direct radiant cooling, I mean that if you place your body at a
> noticeable distance from from panel, you'll feel cold because the
> extreme cold of the coil will draw IR radiation away from your body.
> OTOH, if you touch the panel, you won't feel as cold because the 1st
> layer of the panel is a very poor conductor of heat.
>
> On the ceiling, layer 1 is the lower than layer 2. Layer 3 is the
> highest.
>
>
> Thanks a bunch,
>
> Radium
Maybe if you told us what the intended application is.....
I can't even visualize any application where it would be cost effective to
use a system like that. Just the liquid helium would make it cost
prohibitive.
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