A 60,000 BTU/hr compressor is used to compress air. The air temperature is maintained at a constant 80 °F with this process as a result of heat being rejected to the surrounding which is at 72°F. What is the rate of entropy change of the air?

! Required information NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Five kilograms of air at 427°C and 600 kPa are contained in a piston-cylinder device. The air expands adiabatically until the pressure is 100 kPa and produces 450 kJ of work output. Assume air has constant specific heats evaluated at 300 K. Determine the entropy change of the air in kJ/kg-K. Use the table containing the ideal gas specific heats of various common gases. (You must provide an answer before moving on to the next part.) The entropy change of the air is kJ/kg-K.

A- Air at 15°C and 1bar occupies 0.02 m³. The air is heated at constant volume until the pressure is 5bar, and then cooled at constant pressure back to the original temperature. Calculate the net heat flow to or from the air and the net entropy change. Sketch the process on a T-s diagram. (8.5marks)

A refrigerator transfers 1kJ of heat from a cold region at -20°c to hot region at 30°c. If COP of refrigerator is 4, total entropy change of region's will be:- A. 1.72 X 10-4 KJ/K B. 0.173 KJ/K Ос. 1.7 X 102 кЈ/К D. 0.9263 KJ/K