5. Air enters the compressor of an actual Brayton refrigeration cycle at 100 kPa, 270 K. the compressor and turbine have isentropic efficiencies of 80 and 88%, respectively. The compressor pressure ratio is 3, and the temperature at the turbine inlet is 310 K. Determine (a) The net work input, per unit mass of air flow, in kJ/kg. (b) The refrigeration capacity, per unit mass of air flow, in kJ/kg. (c) The coefficient of performance.

5. Air enters the compressor of an actual Brayton refrigeration cycle at 100 kPa, 270 K. the compressor and turbine have isentropic efficiencies of 80 and 88%, respectively. The compressor pressure ratio is 3, and the temperature at the turbine inlet is 310 K. Determine (a) The net work input, per unit mass of air flow, in kJ/kg. (b) The refrigeration capacity, per unit mass of air flow, in kJ/kg. (c) The coefficient of performance.

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter28: Special Refrigeration Applications

Section: Chapter Questions

Problem 15RQ: Why is two-stage compression popular for extra-low-temperature refrigeration systems?

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Air enters the compressor of an ideal Brayton refrigeration cycle at 100 kPa, 300 K. The compressor pressure ratio is 3.75, and the temperature at the turbine inlet is 350 K. Determine: (a) net work input, per unit mass of air flow, in kJ/kg. (b) refrigeration capacity, per unit mass of air flow, in kJ/kg. (c) coefficient of performance. (d) coefficient of performance of a Carnot refrigeration cycle operating between thermal reservoirs at T_C 5 300 K and T_H 5 350 K, respectively
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A vapor-compression refrigeration system circulates Refrigerant 134a at a rate of 0.15 kg/s. The refrigerant enters the compressor at -10 degees Celcius, 1 bar, and exits at 8 bar. The isentropic compressor efficiency is 76%. There are appreciable pressure drops as the refrigerant flows through the condenser and evaporator. The refrigerant leaves the condenser at 8 bar and 30 degrees Celcius. Ignoring the heat transfer between the compressor and its surroundings, determine: a) The rate at which energy is removed from the refrigerated space in kW b) The coefficient of performance
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