An ammonia refrigerating system has a load of 250 kW and operates at a condensing pressure of 1400 kPa and an evaporating temperature of -20°C. The refrigerant exits at the evaporator with a 5- degree superheat. The vapor enters the compressor suction at 10-degree superheat. The compressed vapor is discharged from the compressor at the condensing pressure and 150°C. The refrigerant exits the condenser as saturated liquid. a. State the enthalpies at each point: Point enthalpy kJ/kg kJ/kg kJ/kg h2 h3 kJ/kg h4 kJ/kg Answer: kg/sec b. Calculate the mass flow of refrigerant kW Determine the size of the motor drive if the mechanical efficiency of the motor- compressor is 77%. Answer: C. *.. kW Calculate the total heat rejected in the condenser. Answer: d. % Determine the refrigerating efficiency of the system. Answer: е.

An ammonia refrigerating system has a load of 250 kW and operates at a condensing pressure of 1400 kPa and an evaporating temperature of -20°C. The refrigerant exits at the evaporator with a 5- degree superheat. The vapor enters the compressor suction at 10-degree superheat. The compressed vapor is discharged from the compressor at the condensing pressure and 150°C. The refrigerant exits the condenser as saturated liquid. a. State the enthalpies at each point: Point enthalpy kJ/kg kJ/kg kJ/kg h2 h3 kJ/kg h4 kJ/kg Answer: kg/sec b. Calculate the mass flow of refrigerant kW Determine the size of the motor drive if the mechanical efficiency of the motor- compressor is 77%. Answer: C. *.. kW Calculate the total heat rejected in the condenser. Answer: d. % Determine the refrigerating efficiency of the system. Answer: е.

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

Chapter22: Condensers

Section: Chapter Questions

Problem 7RQ: When a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be...

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