Many years ago I heard that there was a refrigerator system based on Maxwell’s demon. The demon was an imaginary spirit that could separate out the high speed molecules of a gas and those moving more slowly. The problem is to devise a mechanism to separate the high speed hot molecules of gas and those moving more slowly which is the cold component of the gas. Since high speed molecules, by their movement, occupy more space, a hot gas of a certain volume weighs less than that same volume of that gas cold. Therefore, theoretically, spinning the gas would create a centrifugal force which would force the heavier cold portion of the gas to migrate to the outer portion of the vessel and the hot molecules would move towards the center. I doubt that one spinning vessel could create a useful temperature difference but if a series of spinning containers mounted on the same axle arranged so that either the hot gas or the cold gas would cascade through the vessel series a useful heating or refrigeration effect might be attained.This is the principle used to separate uranium 235 from uranium 238 but the weight difference there is so slight it requires a huge number of centrifuges to be effective. Perhaps refrigeration or heating might be useful at a smaller number of cascades.
I agree
No opinion
I disagree
Add your comment
I suspect "Maxwell's demon" breaks Heissenbergs uncertainty principle (if I remember my physics).
The molecules are in constant motion and constantly hitting each other, and exchanging energy (momentum and speed). They all have different speeds (probably in a normal distribution curve), but the speed of any individual molecule is constantly changing as it impacts with others.
Cold gasses are only heavier "en masse" because there are more in a given volume, individual molecules all have the same mass (ignoring Einsteinian effects).Uranium 235 and Uranium 238 are different molecules with different molecular weights (235 and 238). You probably can separate the Nitrogen and the Oxygen in the atmosphere this way, but you cannot seperate "hot" and "cold" molecules of the same gas.
By spinning a gas you are speeding it up (on average), and hence heating it. This speeding up occurs because some molecules impact the moving container wall and gain momentum, which they pass on to other molecules which they in turn impact.
Net result, a warmer gas which will have a slightly higher pressure at the edges because it is being pressurised by the centripetal force.