A vapor-compression heat pump uses R 12 and provides 30000 Btu/hr of heating. The evaporator pressure is 33 psia, and the refrigerant enters the compressor at 25 F. The compressor's isentropic efficiency is 84%, and the condenser pressure is 130 psia. The electricity to drive the compressor comes from a power plant with an efficiency of 40%. Determine (a) the compressor power; (b) (b) the ratio of heat used in the power plant to produce the electricity to the heat output of the heat pump.

A vapor-compression heat pump uses R 12 and provides 30000 Btu/hr of heating. The evaporator pressure is 33 psia, and the refrigerant enters the compressor at 25 F. The compressor's isentropic efficiency is 84%, and the condenser pressure is 130 psia. The electricity to drive the compressor comes from a power plant with an efficiency of 40%. Determine (a) the compressor power; (b) (b) the ratio of heat used in the power plant to produce the electricity to the heat output of the heat pump.

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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