Problem 6.6 - Adiabatic
Evaluation of a R134a Compressor
A young engineer was assigned to evaluate the
compressor of a proposed R-134a refrigeration system shown below,
and assumed it to be adiabatic.
- a. Under this assumption, and ignoring kinetic
and potential energy effects, determine the specific work input
to the compressor [48.3
kJ/kg].
- b. His supervisor checked the results and
told him that his assumption was incorrect and not physically
feasible. On the h-s diagram below draw the actual compression
process (as assumed) as well as the equivalent isentropic compression
process. Using this diagram, as well as relevant data evaluated
at the inlet and outlet of the compressor, explain how she arrived
at that conclusion.
Derive all equations used starting from the
basic energy equation and the equation for entropy generated.
