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Wind-chill again! How about air conditioning?.............
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Posted 12/7/2018 00:01 (#7154582 - in reply to #7154132)
Subject: RE: Here we go ...

Alton, Ia
You are close, but the theory of air conditioning involves both the compressing and decompressing process, and it has very little to do with the speed of the compressed liquid. It has to do with something called the "Ideal Gas Law" which is PV=nRT. The quick version is when you increase the pressure (P), you also increase the temp (T), since volume (V), gas amount (n) and a gas constant (R) remain constant. So, when you compress the AC gas, be it the old R 12 or R 22 or the new R -32 or R 134, it gets hot. Just like how the pipe from the air compressor pump to the tank gets hot. Then it is passed thru the condenser, which transfers heat from the refrigerant to the surrounding air, lowering the refrigerant energy level, usually low enough the refrigerant is now a liquid. Then, it goes thru the expansion valve, P drops and so does T, and it then absorbs heat from your house, car interior, fridge space, etc. Back thru the compressor and around it goes.

Pretty much any gas could be used as a refrigerant, air could be. NH3 is used very extensively in food processing, and cold storage. It all depends on efficiencies of compression, boiling points, etc.

So it's not the speed of the refrigerant, it's the pressure that counts. When you bleed off an Oxygen or LP tank the gas is dropping in pressure, thus the temp drops and you'll get frost. You can feel the same effect holding a compressed air blow gun.
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