A vapor-compression heat pump has a heating capacity of 500kJ/min and uses Refrigerant 134a as the working fluid. Theisentropic compressor efficiency is 80%. The heat pump is drivenby a power cycle with a thermal efficiency of 25%. For the powercycle, 80% of the heat rejected is transferred to the heatedspace. Data for the cycle are provided in the table below. Theprincipal states are numbered in the Fig. 10.3.State p (bar)2.012212s2341010T (°C)-1045.1752.47349.62.0122 -10h (kJ/kg) s (kJ/kg-K)241.340.9253274.630.92530.95120.35840.3779282.9597.3197.31CoutwwwCondenserExpansionvalveCompressorEvaporatorwwwSaturated orsuperheated vaporFIG. 10.3 Components of a vapor-compressionrefrigeration system.a. Determine the power input to the heat pump compressor, in kW.b. Evaluate the ratio of the total rate that heat is delivered to the heated space to the rate of heat input tothe power cycle. Discuss.

Heating capacity of the heat pump.QH=500 kJ/min. The enthalpy at state 1,h1=241.34 kJ/kg. The…

A vapor-compression heat pump has a heating capacity of 500 kJ/min and uses Refrigerant 134a as the working fluid. The isentropic compressor efficiency is 80%. The heat pump is driven by a power cycle with a thermal efficiency of 25%. For the power cycle, 80% of the heat rejected is transferred to the heated space. Data for the cycle are provided in the table below. The principal states are numbered in the Fig. 10.3. State p (bar) T (°C) 1 2.0122 -10 2s 2 3 45.17 52.47 9.6 34 2.0122 -10 10 10 h (kJ/kg) s (kJ/kg-K) 241.34 0.9253 0.9253 0.9512 0.3584 0.3779 274.63 282.95 97.31 97.31 www Condenser Expansion valve Compressor Evaporator www Saturated or superheated vapor FIG. 10.3 Components of a vapor-compression refrigeration system. a. Determine the power input to the heat pump compressor, in kW. b. Evaluate the ratio of the total rate that heat is delivered to the heated space to the rate of heat input to the power cycle. Discuss.

A vapor-compression heat pump has a heating capacity of 500 kJ/min and uses Refrigerant 134a as the working fluid. The isentropic compressor efficiency is 80%. The heat pump is driven by a power cycle with a thermal efficiency of 25%. For the power cycle, 80% of the heat rejected is transferred to the heated space. Data for the cycle are provided in the table below. The principal states are numbered in the Fig. 10.3. State p (bar) T (°C) 1 2.0122 -10 2s 2 3 45.17 52.47 9.6 34 2.0122 -10 10 10 h (kJ/kg) s (kJ/kg-K) 241.34 0.9253 0.9253 0.9512 0.3584 0.3779 274.63 282.95 97.31 97.31 www Condenser Expansion valve Compressor Evaporator www Saturated or superheated vapor FIG. 10.3 Components of a vapor-compression refrigeration system. a. Determine the power input to the heat pump compressor, in kW. b. Evaluate the ratio of the total rate that heat is delivered to the heated space to the rate of heat input to the power cycle. Discuss.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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6
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Modify the cycle in Problem 10.9 to have an isentropic compressor efficiency of 83% and let the temperature of the liquid leaving the condenser be 100 F. Sketch the T-s diagram for the modified cycle and determine, for the modified cycle, (a) the compressor power, in horsepower. (b) the rate of heat transfer from the working fluid passing through the condenser, in Btu/min. (c) the coefficient of performance. Note: Problem 10-9 is a vapor-compression system of R134a with a mass flow rate of 30.59 lb/min.
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4
A vapor compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated vapor enters the compressor at 2 bar, and saturated liquid exist the condenser at 8 bar. The isentropic compresser efficiency is 80%. The mass flow rate of refrigerant is 7 kg/min. Sketch the process on a T-s diagram and determine; i. the compressor power, in kW ii. the refrigeration capacity, in tons iii. the coefficient of performance