In article , Don Foreman says...

Something can get colder and gain heat at the same
time.

I've always thought of temperature as proportional to heat content in
joules or calories times specific heat of the material holding it.

For this discussion about ideal gasses, the temperature of the
gas is proportional to the internal energy of the atoms, by
a simple proportionality.

E = 3/2 x K x T

The K is the boltzman constant (guy who figured this out),
T is the temperature in degrees kelvin (so-called absolute)
and the 3/2 is there because each degree of mechanical
freedom of an individual gas atom has 1/2 kT of energy.
Because it can move in X, Y, and Z, the total is 3/2.

I think what you were saying was, that there could be
*two* things going on in the regulator at one time.
The first being expansion of the gas, which causes
it to cool. The second being the friction or turbulence
inside the regulator, which causes the gas to heat.

The *net* effect might still be an overall cooling
of the regulator, even though there is some heating
going on from the friction losses. The cooling is
just larger than the heating.

Jim

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