Still interested in purely-radiant cooling.

[Green Xenon [Radium]]

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.

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

[Noon-Air]

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.

[Stormin Mormon]

Give it up, you fool. Cold doesn't radiate.

[What a maroon]

Hi being the opertive word. You must be high to even want to try that. What an asshat.

[Green Xenon [Radium]]

It is to keep a room comfortably cold during the summer.

Call me weird but I prefer my cooling to be directly-radiant and heating to directly involved natural convection of dry air. Just something about radiant cooling that gets my interests going.

[Green Xenon [Radium]]

It doesn't but it can cool you by causing you to radiate heat towards it. The radiant cooler is cold, the subject in the room under the cooler is hot. Physics will attempt to equalize the temperature of the two objects. If there is no conduction or convection between the two objects, then the attempt will be facilitated by making the hotter object emit thermal radiation toward the colder object. This is will cool the hotter object. If you are the hotter object, you will feel cold under the radiant cooler.

[Noon-Air]

Maybe you should be looking at a system that will cost less than the house its going into.

[What a maroon]

Well well, an idiot arguing with a dumbass. Someone pass the popcorn please.

[over a barrel]

Not to mention such a system would instantly cause severe frostburn should any body parts come into contact with it.

[Green Xenon [Radium]]

Why would frostbite occur? The lowest layer [the one a body part would most likely contact] is an extremely poor conductor of heat, so it wouldn't feel that cold. It's the radiant cooling, that would feel cold.

[over a barrel]

Okay I see now what your proposing is using an insulating barier over a radiant heat reciever why Im surprised that I hadnt thought of this idea before--I say go for it dude definately an open market for this type of thing !!!

[Noon-Air]

Sounds like a winner to me... now *prove* to me that it works, and can be sold and installed at a competitive price, retrofit without major construction, with a reasonable profit margin, and can be used in most any cooling application, then I'll run with it.

[geothermaljones]

How big is the liquid Helium pressure vessel? How much energy will be needed to maintain it in a liquid form? How much pressure will there be in the circuit when the Helium vaporizes while absorbing the heat?

If we're to put multiple air handlers around the space to dehumidify, how would said dehumidification take place. Your suggesting some sort of fresh air introduction while exhausting bad indoor air. -Google HRV/ERV- When dehumidifying, what's going to "dry" the air? You'll need some sort of cold coil to accomplish this. Since 70dF 50% RH conditions are what most seek, it's not coincidental that

55dF 100% air is what's needed to accomplish this. as 55dF 100%RH air warms to 70dF the RH levels out at about 50%. -Google Psychrometric Chart- If we're to cool these air handlers with liquid helium as well, refer to the first 3 Questions.

If rather, you use, say, a DX coil for this, wouldn't you be able to find these parts & pieces (& UL Listed) at much more reasonable rates? Further, wouldn't using a single air handling unit with some sort of distribution system, say ductwork, provide a much more cost effective & serviceable system? The sucking & blowing folks would "never" feel can easily be covered with proper placement & balance of said distribution system. Since the building does not have to be structurally re-enforced to carry the weight of the helium containment vessel & panel system, the costs up front could be reduced. Since the electrical system doesn't have to support the power requirements of maintaining liquid helium, the cost of operation would also be lowered. Since many homes require heating during some portions of the year, wouldn't it make sense to provide a simple, sensible (& UL Listed) system for delivering this as well?

Since Heat seeks cold, in any case, the radiant source would be the people rather than the (INSULATED?) ceiling panels. Since Radiant heat is directly proportional to the square of the distance from the heat source. -Google Dulong & Petit, Boyles Law, Newton, etc...- This would mean the fat bald 6' guy (Hey, I resemble that remark) would have a terribly cold head while his feet were still hot.

I could be wrong, but I'm skeptical...

goodluck geothermaljones

[Green Xenon [Radium]]

Ok. Thanks for this info. I just thought that liquid helium gets the coldest of all gases at absolute zero.

Yes.

Exactly.

Ok.

Yes.

This helium thing was mostly a theoretical system I was interested in. I'm interested in a lot of things that are either impossible or barely in the realm of possibility.

Absolutely.

Yes. My theoretical system would involve the floor emitting hot dry air. This convective floor heating is designed in such as way that those on the floor will feel the heat but will not fell any sucking or blowing of air.

The design also ensures that the hot air has absolutely no water vapor or CO2 at all. In addition, this design keeps the air on the lowest part of the house [the air on the ground of the lowest floor] the hottest [using dry convective heat], while things just below the ceiling of the highest floor get the coldest [because of radiant cooling].

Lot of these theoretical things I talk about are way too hypothetical to be true today but they interest me and stir my imagination.

It's my nature to want the opposite of what exists. I think there is too much radiant heating and convective cooling. Hence, I want radiant cooling and convective heating.

Yes. That's what I've been trying to tell everyone. The humans in the room are the thermal radiators and the ceilings absorb that radiant heat.

The ceiling is a thermal non-conductive so that if you touch it, the ceiling won't really feel cold but if you are just below the ceiling w/ out touching it, you will feel cold. The ceiling is made of a material that is extremely poor at conducting heat but clearly allows IR [heat] radiation to pass through.

At the maximum cold setting, if you put your hand just below the ceiling of the highest room of the house [usually the 2nd/3rd floor], your hand will get as cold as it can get w/out causing injury.

As for the convection heating in winter, when set on maximum, the air just above the ground of the lowest room of the house [usually the first floor but sometimes the basement -- if the house has a basement] gets as hot as it can without causing injury.

Even at max, the solid part of the floor itself, doesn't get so hot, but the air right above it does. In the winter, what feels better than some hot dry air under your feet!

I'd just love that cold feeling on top and hot on bottom. I enjoy the rarities.

[geothermaljones]

WTF??? Everything is at it's coldest at absolute zero... Helium, Oxygen, Bananas, Snot, what ever. in fact, everything stops moving at absolute zero. -Google Absolute Zero- When you get to Absolute zero, there are throngs of people that will laud your name... Mankind has never been there, albeit a few hundredths of a degree away... but a man's gotta dream. For the time being, find a NG that deals with intriguing mind benders, this isn't it. I see I've wasted my time. I'll have to defer to the rest of those that said get lost. You've proven yourself to be The Absolute Zero!

eabof geothermaljones

[Green Xenon [Radium]]

Sorry, I meant to say "I just thought that helium has the lowest boiling point." Of all gases it requires the lowest temperature to liquefy. To make helium liquid, one requires temperatures at or near 0 K.

[Green Xenon [Radium]]

As with the ceiling, the material that makes up the floor is also extremely poor at conducting heat. In addition, though, the floor is completely opaque to IR light [i.e. radiant heat]. Hence that only way the floor's heat can be felt is through convection.

Dry convective heat only.

More interesting facts:

The lowest part of the house [ground of the basement or 1st floor] has the lowest air pressure, while the ceiling of the higher part of the house [usually 2nd or 3rd floor] has the highest air pressure. This makes life more intriguing. Higher pressure with less heat. Lower pressure with more heat. Thats how it should be.

[Bob Shuman]

Sounds like you are describing something that is in every kitchen: a residential freezer. It too is very cold inside, but has "an extremely poor conductor of heat" (an insulator) on the outside "where it is most likely to come into contact" with any heat source.

How well does the outside wall of that freezer collect the heat radiated from your body when you are a few feet or even a few inches away?

While I think that innovation starts with "outside the box" thinking, I believe that it still must be based on the laws of THIS universe.

Bob

[Andy Energy]

This sounds sooo complicated.

Why do we humans seem to think we need a complicated solution to a simple problem.

We cannot even get the whole building industry to what is right.

I=92d put my money on great insulation, proper shading, controlled ventilation, proper sized and correctly installed HVAC.

Look into the Austrian Passive house.

Andy Think and do "Whole House Performance"