Liquid Nitrogen or Freon Cooling System

[kappage]

Phase? what is that.

I dont thing sub zero would be needed freon would work just fine and can acheive temps of 18F which i got out of a volkswagen passat vent one time after i rebuilt the ac system.

Indignity's first link seems a pretty good explanation (though I didn't read all of it). Here's the short of it as far as phase change goes...

Think of an air compressor, when the compressor is turned on, it compresses more gas into a smaller space, thus increasing pressure. According to PV~T (Ideal Gas Law), as the Pressure (P) raises and the Volume (V) is constant, the T must rise. Now let that sit in a reservoir a minute so T equals the surrounding temp and uncompress it. As the P drops, so must the T and thats a basic look at how it works (This is how your fridge works and I believe how most A/c units work)

*The size of tubes represents pressure, not volume*

To get a clear idea of the first part, pump up a bike tire with a hand pump really fast...the tire will be slightly warm from the rapid increase in pressure.

A clear idea of the second part, next time you clean you keys with compressed air, pay attn to the temp as you spray, as the pressure in the can drops, so does the temp.

Going back to this, it was in an Exam but mine was done properly with all the different lines and ****, and it also ahd to do with teh question "If you open your fridge in summer will it cool the room?" (answer is no unless you ahng half of the fridge out the door)