How to temporary chill a car with non-working AC.

~^Johnny^~ wrote:
> On Sun, 26 Sep 2004 14:58:07 -0400, Threeducks > wrote:
>
>
>>Nope. There is no heat loss when you pass a fluid through a throttling
>>expansion, but there is a significant temperature drop. Now it's
>>becoming clear that you don't really understand how a refrigeration
>>cycle works.
>
>
>
> You mean expansion valves, orifices, tubes, and the like don't cause a
> negligible friction loss? :-)
>
> Shame on you! :-)
>
>
> All joking aside, throttling (metering) does indirectly cause a heat loss of
> fluid to air, as it forces condensation of the working fluid (latent heat),
> and there is resultant desuperheating and subcooling (sensible heat) involved
> as well.
>

You seem to be confused. The system of interest is a working fluid
passing from upstream of the orfice to downstream, not the rest of the
cycle. The change in enthalpy of a fluid as it passes through a valve
is zero and you can look that up in any thermodynamics textbook. The
energy contained within the fluid does not change as it passes through
the valve! Where would it go? How do you explain your concept of
"heat" in this context where we have a large temperature drop, but no
change in the amount of energy contained by the fluid?

The valve does not cause condensation, that is done in the condenser,
which is before you get to the valve. When you drop pressure with a
valve (or orfice), you vaporize part of the working fluid. How do you
expect to condense a fluid by reducing its pressure?

>
> [Now I'm gonna sound ridiculous, to prove a point:]

You've already sounded quite ridiculous. The only thing you've proven
is you know nothing about refrigeration.