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christopherludw
16-07-2012, 07:55 PM
I have an important NCG question I was hoping one of you engineers could maybe help me with? We all know that the air concentration in the vapor space above a cylinder of R-22 goes up as temperature goes down, due to the condensation of the refrigerant. My question is, what happens to the concentration on the air in the liquid phase in that same tank as the temperature goes down? Does is act like CO2 in water and become more soluble? Or does air act differently in refrigerant and actually decrease in the liquid, with decreased temperature, as it increases in the vapor?

Thanks.

Rob White
17-07-2012, 08:30 AM
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As far as I'm aware air does not react with refrigerant.
Air is Not solubal and will always remain as air and it
will always find the highest part of the cylinder (or fridge system).

Air is a non condensable gas because the pressure inside most systems
is not high enough for air (N2 & O2) to saturate. Its volume can change
but it will never saturate at normal refrigeration pressures.
The result is air just sits there and takes up space. If air takes up space
the refrigerant can't do its job, which in most cases is condense.

Regards

Rob

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D.D.KORANNE
31-07-2012, 12:57 PM
besides, it can contribute to oil contamination/carbonization , sludge formation due to heat since condensing pressure & temp would go up ..................

RANGER1
31-07-2012, 09:08 PM
The way I understand it If air is in top part of full or partly full refrigerant bottle, the pressure will be higher than its saturated temp.
Same as if mixed gases the pressure won't match saturated temp of that refrigerant.

PaulZ
03-08-2012, 02:47 AM
Hi Ranger
You are right, when there are non-condensables in a system yous Dalton's Law - The total pressure of a mixture of gases is equal to the sum of the partial pressures that each gas would exert if they occupied the space alone. PT = P1 + P2.
This is how you determine if a system has non-condensables.
Regards
Paul