A two-stage compression refrigeration system operates between the pressure limits of 0.10 MPa and 1.0 MPa. Refrigerant134-a is used as the working fluid in the refrigeration system. The refrigerant leaves the condenser at 38°C and is throttled to a flash chamber operating at 0.60 MPa. The refrigerant leaves the low-pressure compressor at 0.60 MPa and flows to a mixing chamber, then mixed with the saturated vapour separated from the flash chamber. The vapour from the mixing chamber is then compressed to the condenser pressure by the high-pressure compressor. The saturated liquid from the flash chamber is throttled to the evaporator pressure. The mass flow rate through the condenser is 0.3 kg/s. The refrigerant leaves the evaporator at -10°C. Assume that both compression processes are isentropic. ii) iii) iv) Sketch and label the cycle on a P-h diagram. Calculate the mass flow rate of the saturated vapour leaves the flash chamber, kg/s. Determine the rate of heat removed from the refrigerated space, kW. Calculate the coefficient of performance (COP) of the refrigeration system.

A two-stage compression refrigeration system operates between the pressure limits of 0.10 MPa and 1.0 MPa. Refrigerant134-a is used as the working fluid in the refrigeration system. The refrigerant leaves the condenser at 38°C and is throttled to a flash chamber operating at 0.60 MPa. The refrigerant leaves the low-pressure compressor at 0.60 MPa and flows to a mixing chamber, then mixed with the saturated vapour separated from the flash chamber. The vapour from the mixing chamber is then compressed to the condenser pressure by the high-pressure compressor. The saturated liquid from the flash chamber is throttled to the evaporator pressure. The mass flow rate through the condenser is 0.3 kg/s. The refrigerant leaves the evaporator at -10°C. Assume that both compression processes are isentropic. ii) iii) iv) Sketch and label the cycle on a P-h diagram. Calculate the mass flow rate of the saturated vapour leaves the flash chamber, kg/s. Determine the rate of heat removed from the refrigerated space, kW. Calculate the coefficient of performance (COP) of the refrigeration system.

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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