QUESTION 4 (PLO2 / CLO3 / C4) (20 marks) A commercial refrigerator uses refrigerant-134a as the working fluid and enters

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Question 4 Plo2 Clo3 C4 20 Marks A Commercial Refrigerator Uses Refrigerant 134a As The Working Fluid And Enters 1 (61.3 KiB) Viewed 24 times

QUESTION 4 (PLO2 / CLO3 / C4) (20 marks) A commercial refrigerator uses refrigerant-134a as the working fluid and enters the compressor at 100 kPa and -20°C at a rate of 0.75 m³/min and leaves at 0.8 MPa. The isentropic efficiency of the compressor is 76%. The refrigerant-134a enters the throttling valve at 0.8 MPa and 26°C and leaves the evaporator as saturated vapor at -26°C. (a) Illustrate the cycle on a T-s diagram with respect to saturation lines. (b) Explain the principle of this commercial refrigerator. (c) Determine the coefficient of performance of the refrigerator. (d) Determine the minimum power requirement to the compressor for the same rate of heat absorbed (in kW). (2 marks) (5 marks) (5 marks) (8 marks)