Consider a two-stage cascade refrigeration system operating between the pressure limits of 0 8 and 0.14 MPa Each stage operates on the ideal vapour compression refrigeration cycle with refrigerant-134a as the working fluid Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counter flow heat exchanger where both streams enter at about 0.4 MPa. If the mass flow rate of the refrigerant through the upper cycle is 024 kgls, detemine the coefficient of performance of this cascade refrigerator.

Consider a two-stage cascade refrigeration system operating between the pressure limits of 0 8 and 0.14 MPa Each stage operates on the ideal vapour compression refrigeration cycle with refrigerant-134a as the working fluid Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counter flow heat exchanger where both streams enter at about 0.4 MPa. If the mass flow rate of the refrigerant through the upper cycle is 024 kgls, detemine the coefficient of performance of this cascade refrigerator.

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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1. Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.2 MPa and 200 kPa with refrigerant-134a as the working fluid.Heat rejection from the lower to the upper cycle takes place in a countercurrent adiabatic heat exchanger where the pressures in the upper and lower cycles are 0.4 and 0.5 MPa, respectively. In both cycles the refrigerant is a saturated liquid at the condenser outlet and a saturated vapor at the compressor inlet, and the isentropic efficiency of the compressor is 80 percent.The mass flow rate of the refrigerant in the lower cycle is 0.15 kg/s.Determine the following:a) the mass flow of the refrigerant through the upper cycle,b) the rate of removal from the refrigerated space andc) the COP of this refrigerator.d) Draw the T-s graph of the complete system and the diagram with all the components and processes of both cycles, indicate all the states in both cases (1, 2, 3….)
Consider a two-stage cascade refrigeration system operating between the pressure limits of 0.8 and 0.14 MPa. Each stage operates on the ideal vapor-compression refrigeration cycle with refrigerant-134a as the working fluid. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where both streams enter at about 0.4 MPa. If the mass flow rate of the Refrigerant through the upper circle is 0.24 kg/s, determine (a)the mass flow rate of the refrigerant through the lower cycle, (b)the rate of heat removal from the refrigerated space and the power input to the compressor, and (c)the coefficient of performance of this cascade refrigerator. Answers: (a) 0.195 kg/s, (b) 34.2 kW, 7.63 kW, (c) 4.49
Consider a two-stage cascade refrigeration system operating between the pressure limits of 0.8 and 0.14 MPa. Each stage operates on the ideal vapor-compression refrigeration cycle with refrigerant-134a as the working fluid. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counter-flow heat exchanger where both streams enter at about 0.4 MPa. If the mass flow rate of the refrigerant through the upper cycle is 0.24 kg/s, determine (a) the mass flow rate of the refrigerant through the lower cycle, (b) the rate of heat removal from the refrigerated space and the power input to the compressor, (c) the coefficient of performance of this cascade refrigerator, and (d) the intermediate pressure of the cascade cycle. For full credit, accurately, neatly draw the cascade system on an electronic PDF p-h diagram. Please only solve part d. If possible, show the ph diagram
Consider a two-stage cascade refrigeration system operating between the pressure limits of 2 MPa and 0.05 MPa. Each stage operates on an ideal vapor-compression refrigeration cycle with R-134a as the working fluid. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where both streams enter at 0.5 MPa. If the mass flow rate of the refrigerant through the upper cycle is 0.25 kg/s, What would the COP be if the heat exchanger pressure were 0.7 MPa. Group of answer choices 2.50 1.50 1.48 1.51
Consider a two-stage cascade refrigeration system operating between -80 o C and 80 o C. Each stage operates on an ideal vapor-compression refrigeration cycle. Upper cycle use R-12 as working fluid, lower cycle use R-13. In the lower cycle refrigerant condenses at 0 o C, in the upper cycle refrigerant evaporates at -5 o C. If the mass flow rate in the lower cycle is 1 kg/s, determine the mass flow rate through the upper cycle. Group of answer choices 1.56 kg/s 2.46 kg/s 1.78 kg/s 2.30 kg/s
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