Radiant Cooling with Liquid Nitrogen

[GreenXenon]

Hi:

I thinking of a radiant cooling device for houses and buildings in which the cooling -- in the direct sense -- involves only radiation. Sort of like a glass-ceramic radiant-stove-top in reverse. Indirectly, however, some amount of convection and conduction will be needed [liquid nitrogen, cold metals]. The cooling panel is the ceiling and cools objects below it.

Quote from

:

"A glass-ceramic stove uses radiant heating coils as the heating elements. The surface of the glass-ceramic cooktop above the burner heats up, but the adjacent surface remains cool because of the low heat conduction coefficient of the material."

Here is an example of a radiant stovetop switched on:

My theoretical glass-ceramic radiant cooler is similar to the infrared radiant stovetop described in the wikipedia link, except:

1. It faces downward
2. The coils are hollow [as opposed to being solid all the way through], this hollow within the coils allows liquid nitrogen to flow through them can cool them down to near absolute zero
3. Liquid nitrogen -- not electricity -- flows through the coils.
4. Obviously, the coils get cold instead of hot.

The radiant cooling panel is on the ceiling of the room it is supposed to cool. Those standing under it will feel cold.

Yes, heat absorbed into the radiant cooling panels is carried off using convection and conduction -- but this is not what the subject inside the room feels. The direct cooling effect on anything/anyone inside the room is radiant.

By direct radiant cooling, I mean that if you place your body at a noticeable distance from panel, you'll feel cold because the extreme cold of the coil will draw IR radiation away from your body.

I=92m thinking of more intense versions of this hypothetical glass ceramic radiant infrared cooler to be used in refrigerators and freezers.

This radiant cooling is something that I am deeply interested in. I don't know why.

Radiant cooling will feel to the object like "cold rays" just like radiant heating feels like "heat rays".

I know there is no such thing as "cold rays", it's simply heat radiating from my body to a colder object. My body is giving of heat rays causing it's temperature to lower, thereby giving me a perception of coldness.

Thanks a bunch,

Green Xenon

[Steve]

I thinking of a radiant cooling device for houses and buildings in which the cooling -- in the direct sense -- involves only radiation. Sort of like a glass-ceramic radiant-stove-top in reverse. Indirectly, however, some amount of convection and conduction will be needed [liquid nitrogen, cold metals]. The cooling panel is the ceiling and cools objects below it.

Quote from

:

"A glass-ceramic stove uses radiant heating coils as the heating elements. The surface of the glass-ceramic cooktop above the burner heats up, but the adjacent surface remains cool because of the low heat conduction coefficient of the material."

Here is an example of a radiant stovetop switched on:

My theoretical glass-ceramic radiant cooler is similar to the infrared radiant stovetop described in the wikipedia link, except:

1. It faces downward
2. The coils are hollow [as opposed to being solid all the way through], this hollow within the coils allows liquid nitrogen to flow through them can cool them down to near absolute zero
3. Liquid nitrogen -- not electricity -- flows through the coils.
4. Obviously, the coils get cold instead of hot.

The radiant cooling panel is on the ceiling of the room it is supposed to cool. Those standing under it will feel cold.

Yes, heat absorbed into the radiant cooling panels is carried off using convection and conduction -- but this is not what the subject inside the room feels. The direct cooling effect on anything/anyone inside the room is radiant.

By direct radiant cooling, I mean that if you place your body at a noticeable distance from panel, you'll feel cold because the extreme cold of the coil will draw IR radiation away from your body.

I?m thinking of more intense versions of this hypothetical glass ceramic radiant infrared cooler to be used in refrigerators and freezers.

This radiant cooling is something that I am deeply interested in. I don't know why.

Radiant cooling will feel to the object like "cold rays" just like radiant heating feels like "heat rays".

I know there is no such thing as "cold rays", it's simply heat radiating from my body to a colder object. My body is giving of heat rays causing it's temperature to lower, thereby giving me a perception of coldness.

Thanks a bunch,

Green Xenon

--------------------------------------------

Questions.........

How much energy is expended to produce the liquid N2??

How are you going to deal with the condensate?? Remember that 90% of air conditioning is humidity control.

[GreenXenon]

To prevent water from condensing on the panel, a separate air- dehumidifier is used.

[John Larkin]

Because it won't work!

John

[linnix]

I guess you never plan on selling those houses.

Buyer: You have a liquid nitrogen what? How much would it costs to tear it down. I need $10,000 credits just in case.

[tm]

Thanks a bunch,

Green Xenon

________________________________

Please don't feed the trolls.

[Tim Wescott]

We live our lives in an ambient temperature of around 330K. A heating coil that's glowing orange is at about 930K -- that's a 600K difference. A cooling coil can go no lower than 0K -- that's only a 330K difference, or half of what you can easily attain with a hunk of wire and some electrical power (or a burning piece of a tree).

An object that's hotter than ambient will enjoy a local humidity that's lower than the surrounding air, driving any water and other materials

-out- of the coil. An object that's much cooler than ambient will enjoy a local humidity that's much higher than surrounding air. If you actually managed to get a coil down to LN2 temperatures, and exposed it to the air, it would become coated with water ice. If it weren't coated with water ice, it'd get dry ice on it. If it didn't get dry ice on it, oxygen would condense on the surface.

We haven't even started on the basic thermodynamic inefficiencies involved in trying to cool an area by making heat flow across such huge gradients -- but they're there, and they're big, and unlike heating, where all such heat flow just generates more heat and helps you, here all such heat flow just generates more heat and hurts you.

So sure -- expensive to build, low performance, inconvenient to operate, hugely wasteful to run. Other than that, it should be a snap.

[Grumpy]

Thinking of radiant cooling would do better by having couple glasses of good Bourbon!!!

I thinking of a radiant cooling device for houses and buildings in which the cooling -- in the direct sense -- involves only radiation. Sort of like a glass-ceramic radiant-stove-top in reverse. Indirectly, however, some amount of convection and conduction will be needed [liquid nitrogen, cold metals]. The cooling panel is the ceiling and cools objects below it.

Quote from

:

"A glass-ceramic stove uses radiant heating coils as the heating elements. The surface of the glass-ceramic cooktop above the burner heats up, but the adjacent surface remains cool because of the low heat conduction coefficient of the material."

Here is an example of a radiant stovetop switched on:

My theoretical glass-ceramic radiant cooler is similar to the infrared radiant stovetop described in the wikipedia link, except:

1. It faces downward
2. The coils are hollow [as opposed to being solid all the way through], this hollow within the coils allows liquid nitrogen to flow through them can cool them down to near absolute zero
3. Liquid nitrogen -- not electricity -- flows through the coils.
4. Obviously, the coils get cold instead of hot.

The radiant cooling panel is on the ceiling of the room it is supposed to cool. Those standing under it will feel cold.

Yes, heat absorbed into the radiant cooling panels is carried off using convection and conduction -- but this is not what the subject inside the room feels. The direct cooling effect on anything/anyone inside the room is radiant.

By direct radiant cooling, I mean that if you place your body at a noticeable distance from panel, you'll feel cold because the extreme cold of the coil will draw IR radiation away from your body.

I?m thinking of more intense versions of this hypothetical glass ceramic radiant infrared cooler to be used in refrigerators and freezers.

This radiant cooling is something that I am deeply interested in. I don't know why.

Radiant cooling will feel to the object like "cold rays" just like radiant heating feels like "heat rays".

I know there is no such thing as "cold rays", it's simply heat radiating from my body to a colder object. My body is giving of heat rays causing it's temperature to lower, thereby giving me a perception of coldness.

Thanks a bunch,

Green Xenon

[.p.jm.]

And then the panel becomes immediately frosted over, and then quickly iced over. Said ice being a good insulator ( ask any Eskimo ). Oops.

'Flows' under what impetus ? Pressure ? Pressure created how, where, at what power cost ? And the nitrogen goes where ? Atmospheric release ? So, you get new Nitrogen where ? At what power cost ?

No, it will be well insulated with ice after a very few minutes, and those standing under it will feel mainly the drip-drip-drip of the surface of that ice melting on them.

Also, any little kids who jump up and put their tongues on it will hang there in the middle of the room, stuck to your 'near absolute zero' plate :-)

[.p.jm.]

But ...but ... besides that ??? :-)

[linnix]

May be millions to insure that, if even possible. Raining liquid nitrogen (pipe burse) is no joke.

[jbriggs444]

ood Bourbon!!!

If you must top-post, do so elsewhere. Why do you think they came up with /dev/null?

[GreenXenon]

In this theoretical device, the coil is in a vacuum and not exposed to any air. Just like the coils here:

[Steve]

In this theoretical device, the coil is in a vacuum and not exposed to any air. Just like the coils here:

---------------------------------------------------

You will still have the problem of the coil envelope being below dew point.... What are you going to do with the ice/condensate??.... unless you

*want* it to rain in the space.

[Tim Wescott]

If you put an IR-clear window between the coil and the rest of the room, and if the window gets heated faster than it gets cooled (ya, sure), and if it never gets stuck in thermal runaway because of condensation that both insulates and radiates IR, then it would work -- for even more $$.

[.p.jm.]

And as the heat leaves that outer layer, via radiation across your vacumn, bringing your 'protective layer' to some point between room temperature and absolute zero ( and FAR FAR BELOW freezing ) .. then what ?

Really, try to think at least a LITTLE bit before posting.

[.p.jm.]

>

This is starting to sound like it needs a Congressional Appropriation for further study.

Under TARP and other stimuli funds, I'm sure it can be arranged, too.

[Grumpy]

Mr. Briggs you don't like my wise remark hmmm I will cry all night long.

Stupidity is not my coup of tea and maybe you should stop cross posting!

If you must top-post, do so elsewhere. Why do you think they came up with /dev/null?

[Michael A. Terrell]

That's why no one survives winters in Alaska!

[Daniel who wants to know]

Mmmmmm... Yummy Soylent Green lol.