Question

Refrigerant-134a enters an adiabatic compressor as saturated vapor at 160 kPa at a rate of 2.4 m3/min and is compressed to a pressure of 900 kPa. Determine the minimum power that must be supplied to the compressor. Use the tables for R-134a

Answer 1

11.65kW

Step-by-step explanation:

Step one:

given data

from the table for R-134a

For the given pressure state the following data were extracted.

s=0.94202kJ/kg.K

h1=241.14kJ/kg

∝1=0.12355m^3/kg

By interpolation, the final enthalpy and pressure with data from the table of R-134a

h2=277.12kJ/kg

The minimum power output is then determined from the energy balance

W=m(h2-h1)

W=V1/∝1(h2-h1)

W=2.4/60/0.12355(277.12-241.14)

W=0.04/0.12355(35.98)

W=0.3237(35.98)

W=11.65kW Approx.

The minimum power output of the compressor is 11.65kW