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 nitrogen/helium, cold metals]. The cooling panels are on the ceiling and walls.
My visualization is that the radiant cooling panel contain extremely cold metallic coils [cooled by liquid nitrogen and/or helium], this would probably be deepest part of the panel.
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 nitrogen/helium would be flowing through]
Sorry is my visualization is vague, I myself am getting confused by it.
Can anyone think of a more efficient way for direct radiant cooling?
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.
> 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 nitrogen/helium, cold metals]. The cooling panels are > on the ceiling and walls.
> My visualization is that the radiant cooling panel contain extremely > cold metallic coils [cooled by liquid nitrogen and/or helium], this > would probably be deepest part of the panel.
> 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 nitrogen/helium would be > flowing through]
> Sorry is my visualization is vague, I myself am getting confused by > it.
> Can anyone think of a more efficient way for direct radiant cooling?
> 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.
> Thanks a bunch,
> Radium
How are you going to deal with the condensation and the resultant water runoff??
>> 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 nitrogen/helium, cold metals]. The cooling panels are >> on the ceiling and walls.
>> My visualization is that the radiant cooling panel contain extremely >> cold metallic coils [cooled by liquid nitrogen and/or helium], this >> would probably be deepest part of the panel.
>> 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 nitrogen/helium would be >> flowing through]
>> Sorry is my visualization is vague, I myself am getting confused by >> it.
>> Can anyone think of a more efficient way for direct radiant cooling?
>> 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.
>> Thanks a bunch,
>> Radium
> How are you going to deal with the condensation and the resultant water > runoff??
and what if the kids are already pole lickers? you'd need tongue defrosters.
> On Jul 12, 1:12 pm, "Noon-Air" <Noon-...@comcast.net> wrote:
>> How are you going to deal with the condensation and the resultant water >> runoff??
> I don't know, that's why I'm asking about this theoretical cooling > device in these NGs.
Thats fine, but please consider that if your theoritical cooling device worked without having humidity and condensations problems, then everybody would already have one. Think radient floor heat, and then what is gonna happen if you try reverse it and cool the floor.....its gonna get real wet.
On Jul 12, 8:51 pm, "Noon-Air" <Noon-...@comcast.net> wrote:
> Thats fine, but please consider that if your theoritical cooling device > worked without having humidity and condensations problems, then everybody > would already have one. Think radient floor heat, and then what is gonna > happen if you try reverse it and cool the floor.....its gonna get real wet.
So would this cooling device world best in low humidity -- so that there is little condensation?
>>> How are you going to deal with the condensation and the resultant water >>> runoff??
>> I don't know, that's why I'm asking about this theoretical cooling >> device in these NGs.
>Thats fine, but please consider that if your theoritical cooling device >worked without having humidity and condensations problems, then everybody >would already have one.
Exactly. And, more so ( the others could be dealt with ) if the cost of the expendables ( LN ) was cost effective.
IOW ( and this is very common in certain applications, not space comfort cooling ), a simple coil and fan setup ( it could even be the one you already have ), with liquid nitrogen metered through it, and exhaused outside, as the cooling medium. Poof, all the other issues go away, and the only remaining one is cost effectiveness. But it's not done. Tells you something.
> Think radient floor heat, and then what is gonna >happen if you try reverse it and cool the floor.....its gonna get real wet.
Paul ( pjm @ pobox . com ) - remove spaces to email me 'Some days, it's just not worth chewing through the restraints.' 'With sufficient thrust, pigs fly just fine.' HVAC/R program for Palm PDA's Free demo online at www.pmilligan.net/palm/ Free 'People finder' program now at www.pmilligan.net/finder.htm
>> Thats fine, but please consider that if your theoritical cooling device >> worked without having humidity and condensations problems, then everybody >> would already have one. Think radient floor heat, and then what is gonna >> happen if you try reverse it and cool the floor.....its gonna get real wet.
>So would this cooling device world best in low humidity -- so that >there is little condensation?
The condensation is easily dealt with, every AC and refrigeration unit unit in existence today does it already, it's not the major issue. Cost of operation is.
FWIW - LN is typically used when a very fast flash freeze is required. It's a simple system - one solenoid, feeds a metering device and an evaporator ( coil, plate, whatever ). It's applicable when a very fast high-capacity drop is required. Also in cryo work, of course, but that's a different application entirely, where the subject is likely to exposed directly to the LN.
Paul ( pjm @ pobox . com ) - remove spaces to email me 'Some days, it's just not worth chewing through the restraints.' 'With sufficient thrust, pigs fly just fine.' HVAC/R program for Palm PDA's Free demo online at www.pmilligan.net/palm/ Free 'People finder' program now at www.pmilligan.net/finder.htm
On Jul 12, 9:16 pm, .p.jm@see_my_sig_for_address.com wrote:
> IOW ( and this is very common in certain applications, not > space comfort cooling ), a simple coil and fan setup ( it could even > be the one you already have ), with liquid nitrogen metered through > it, and exhaused outside, as the cooling medium. Poof, all the other > issues go away, and the only remaining one is cost effectiveness. But > it's not done. Tells you something.
If a fan setup is used, then would be convective -- not radiant -- cooling.
In my hypothetical radiant cooling system, the only 'convection', is the supercooled nitrogen/helium being pumped in and out of metal coils which are big enough and have enough space inside them for the supercooled liquid to be pumped in and out of them.
The air temperature inside the room being cooled by this devices does not change much. OTOH, the solids and liquids very easily cooled.
> >> Thats fine, but please consider that if your theoritical cooling device > >> worked without having humidity and condensations problems, then everybody > >> would already have one. Think radient floor heat, and then what is gonna > >> happen if you try reverse it and cool the floor.....its gonna get real wet.
> >So would this cooling device world best in low humidity -- so that > >there is little condensation?
> The condensation is easily dealt with, every AC and refrigeration unit > unit in existence today does it already, it's not the major issue. > Cost of operation is.
Okay
> FWIW - LN is typically used when a very fast flash freeze is required. > It's a simple system - one solenoid, feeds a metering device and an > evaporator ( coil, plate, whatever ). It's applicable when a very > fast high-capacity drop is required. Also in cryo work, of course, > but that's a different application entirely, where the subject is > likely to exposed directly to the LN.
>> IOW ( and this is very common in certain applications, not >> space comfort cooling ), a simple coil and fan setup ( it could even >> be the one you already have ), with liquid nitrogen metered through >> it, and exhaused outside, as the cooling medium. Poof, all the other >> issues go away, and the only remaining one is cost effectiveness. But >> it's not done. Tells you something.
>If a fan setup is used, then would be convective -- not radiant -- >cooling.
OK, turn the freaking fan off :-)
Put your panel somewhere, with a drain pan under it. My point stands.
>In my hypothetical radiant cooling system, the only 'convection', is >the supercooled nitrogen/helium being pumped in and out of metal coils >which are big enough and have enough space inside them for the >supercooled liquid to be pumped in and out of them.
Why not simplify the question, and posit a panel cooled by ' standard' refrigeration ? Because really the working fluid doesn't affect your question.
And no, panels woudl not be effective, because radiant heat moves from high to low, 'pushed' from the high. To 'pull' it, your motive force, instead of coming from the high energy point at a direct one to one 'push', would fall off at the inverse square of the distance to the 'pulling' force, IOW it would be ineffective.
>The air temperature inside the room being cooled by this devices does >not change much. OTOH, the solids and liquids very easily cooled.
Paul ( pjm @ pobox . com ) - remove spaces to email me 'Some days, it's just not worth chewing through the restraints.' 'With sufficient thrust, pigs fly just fine.' HVAC/R program for Palm PDA's Free demo online at www.pmilligan.net/palm/ Free 'People finder' program now at www.pmilligan.net/finder.htm
