An air-conditioner operates on the vapor-compression

Chapter 11, Problem 112P

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Problem 112P

An air-conditioner operates on the vapor-compression refrigeration cycle with refrigerant-134a as the refrigerant. The air conditioner is used to keep a space at 21°C while rejecting the waste heat to the ambient air at 37°C. The refrigerant enters the compressor at 180 kPa superheated by 2.7°C at a rate of 0.06 kg/s and leaves the compressor at 1200 kPa and 60°C. R-134a is sub- cooled by 6.3°C at the exit of the condenser. Determine (a) the rate of cooling provided to the space, in Btu/h, and the COP, (b) the isentropic efficiency and the exergy efficiency of the compressor, (c) the exergy destruction in each component of the cycle and the total exergy destruction in the cycle, and (d) the minimum power input and the second-law efficiency of the cycle.