, Peter Kesselman
Pete, your spelling is good. Ideal compression is actually an 'isentropic'
process (a process at constant entropy), which happens to be a type of
adiabatic process. An adiabatic process is basically a concept for people
who like studying thermodynamic processes. It's a process in which heat is
not gained or lost across the system being defined. 'Real' thermodynamic
processes can only approach 'adiabatic' processes. In the case of compressors,
actual discharge temperatures will generally exceed the temperatures
predicted by the isentropic process.
Another adiabatic process is the throttling process, which occurs at constant
entropy. The TEV throttling process is a good example of this.
>I understand that R23 has a higher adiabatic heat than R13 or R503. We are
currently doing a retrofit on a cascade system with dual 2 HP hermetics
(with POE), R23 in low side, HP80 in high side. The system works great,
with plenty of capacity, except the R23 discharge line is running up to
300 deg C. I think this has something to do with the heat of
compression. We are going to install a CPR valve to try to limit the
load. Any suggestions?
The high discharge temperatures of R-23 (and R-22 and R-717--ammonia) is the
nature of these refrigerants. The use of a desuperheating valve (and
an appropriately sized condenser coil) will go a long way to resolving
high discharge temperatures.
Andy Schoen
>What exactly is heat of compression or adiabatic (sp?) heat.
aschoen@mo.net
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