# 02.15 Closed and Steady-State Open Systems

### Ideal gas compression

Adiabatic Compression of an Ideal Gas (LearnChemE.com, 6min) calculate adiabatic temperature for compression of an ideal gas, both reversibly and irreversibly.

Comprehension Questions:
1. 10 mol/s of air is compressed adiabatically and reversibly from 298K and 1bar to 5 bar.
(a) Compute the exit temperature (K). (Hint: check out Eqn. 2.51.)
(b) Compute the power requirement (kW) for this compressor.
(c) Suppose the compressor was only 75% efficient, where efficiency≡Wrev/Wact for compression. Is the temperature of the irreversible compressor higher or lower than that of the reversible compressor? Explain.
(d) Calculate the temperature exiting a 75% efficient compressor.
2. Air is expanded adiabatically and reversibly (through a turbine) from 298K and 5 bar to 1 bar.
(a) Is the outlet temperature higher or lower than 298K?
(b) Suppose the air was expanded through a 50% efficient turbine. Would the temperature be higher or lower than the reversible turbine? Explain.