Thermodynamics: An Engineering Approach
8th Edition
ISBN: 9780073398174
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 11.10, Problem 49P
A certain application requires maintaining the refrigerated space at −32°C. Would you recommend a simple refrigeration cycle with refrigerant-134a or a two-stage cascade refrigeration cycle with a different refrigerant at the bottoming cycle? Why?
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I want to design an air-conditioning system that operates on the ideal vapor-compression refrigeration cycle with min temperature of the evaporator of 20°C. To increase the COPR of the cycle, I am considering replacing the refrigerant R134a as the working fluid with pure water. Do you think such a system is possible? If yes, explain why you would or would not recommend such a system.
Can I please get a in depth answer for this question. Thanks.
Required information
NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part.
Consider a two-stage cascade refrigeration cycle with a flash chamber as shown in the figure with refrigerant-134a as the
working fluid. The evaporator temperature is -10°C and the condenser pressure is 1600 kPa. The refrigerant leaves the
condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. Part of the refrigerant
evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor.
The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash
chamber is throttled to the evaporator pressure and cools the refrigerated space as it vaporizes in the evaporator. The
mass flow rate of the refrigerant through the low-pressure compressor is 0.11 kg/s. Assume that the refrigerant leaves the
evaporator as a saturated vapor and…
Required information
NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part.
Consider a two-stage cascade refrigeration cycle with a flash chamber as shown in the figure with refrigerant-134a as the
working fluid. The evaporator temperature is -10°C and the condenser pressure is 1600 kPa. The refrigerant leaves the
condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. Part of the refrigerant
evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor.
The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash
chamber is throttled to the evaporator pressure and cools the refrigerated space as it vaporizes in the evaporator. The
mass flow rate of the refrigerant through the low-pressure compressor is 0.11 kg/s. Assume that the refrigerant leaves the
evaporator as a saturated vapor and…
Chapter 11 Solutions
Thermodynamics: An Engineering Approach
Ch. 11.10 - Why is the reversed Carnot cycle executed within...Ch. 11.10 - Why do we study the reversed Carnot cycle even...Ch. 11.10 - 11–3 A steady-flow Carnot refrigeration cycle uses...Ch. 11.10 - Does the ideal vapor-compression refrigeration...Ch. 11.10 - Why is the throttling valve not replaced by an...Ch. 11.10 - It is proposed to use water instead of...Ch. 11.10 - In a refrigeration system, would you recommend...Ch. 11.10 - Does the area enclosed by the cycle on a T-s...Ch. 11.10 - Consider two vapor-compression refrigeration...Ch. 11.10 - The COP of vapor-compression refrigeration cycles...
Ch. 11.10 - An ice-making machine operates on the ideal...Ch. 11.10 - A 10-kW cooling load is to be served by operating...Ch. 11.10 - 11–13 An ideal vapor-compression refrigeration...Ch. 11.10 - 11–14 Consider a 300 kJ/min refrigeration system...Ch. 11.10 - 11–16 Repeat Prob. 11–14 assuming an isentropic...Ch. 11.10 - 11–17 Refrigerant-134a enters the compressor of a...Ch. 11.10 - A commercial refrigerator with refrigerant-134a as...Ch. 11.10 - 11–19 Refrigcrant-134a enters the compressor of a...Ch. 11.10 - A refrigerator uses refrigerant-134a as the...Ch. 11.10 - The manufacturer of an air conditioner claims a...Ch. 11.10 - Prob. 23PCh. 11.10 - How is the second-law efficiency of a refrigerator...Ch. 11.10 - Prob. 25PCh. 11.10 - Prob. 26PCh. 11.10 - Prob. 27PCh. 11.10 - 11–28 Bananas are to be cooled from 28°C to 12°C...Ch. 11.10 - A vapor-compression refrigeration system absorbs...Ch. 11.10 - A refrigerator operating on the vapor-compression...Ch. 11.10 - A room is kept at 5C by a vapor-compression...Ch. 11.10 - Prob. 32PCh. 11.10 - 11–33 A refrigeration system operates on the ideal...Ch. 11.10 - When selecting a refrigerant for a certain...Ch. 11.10 - Consider a refrigeration system using...Ch. 11.10 - A refrigerant-134a refrigerator is to maintain the...Ch. 11.10 - A refrigerator that operates on the ideal...Ch. 11.10 - A heat pump that operates on the ideal...Ch. 11.10 - Do you think a heat pump system will be more...Ch. 11.10 - What is a water-source heat pump? How does the COP...Ch. 11.10 - Prob. 42PCh. 11.10 - Refrigerant-134a enters the condenser of a...Ch. 11.10 - Prob. 45PCh. 11.10 - A heat pump using refrigerant-134a heats a house...Ch. 11.10 - How does the COP of a cascade refrigeration system...Ch. 11.10 - A certain application requires maintaining the...Ch. 11.10 - Consider a two-stage cascade refrigeration cycle...Ch. 11.10 - Can a vapor-compression refrigeration system with...Ch. 11.10 - Prob. 52PCh. 11.10 - Prob. 53PCh. 11.10 - Repeat Prob. 1156 for a flash chamber pressure of...Ch. 11.10 - Prob. 56PCh. 11.10 - Prob. 57PCh. 11.10 - 11–58 Consider a two-stage cascade refrigeration...Ch. 11.10 - Prob. 59PCh. 11.10 - A two-evaporator compression refrigeration system...Ch. 11.10 - A two-evaporator compression refrigeration system...Ch. 11.10 - Repeat Prob. 1163E if the 30 psia evaporator is to...Ch. 11.10 - How does the ideal gas refrigeration cycle differ...Ch. 11.10 - Devise a refrigeration cycle that works on the...Ch. 11.10 - How is the ideal gas refrigeration cycle modified...Ch. 11.10 - Prob. 66PCh. 11.10 - How do we achieve very low temperatures with gas...Ch. 11.10 - 11–68E Air enters the compressor of an ideal gas...Ch. 11.10 - Prob. 69PCh. 11.10 - Air enters the compressor of an ideal gas...Ch. 11.10 - Repeat Prob. 1173 for a compressor isentropic...Ch. 11.10 - Prob. 73PCh. 11.10 - Prob. 74PCh. 11.10 - Prob. 75PCh. 11.10 - A gas refrigeration system using air as the...Ch. 11.10 - An ideal gas refrigeration system with two stages...Ch. 11.10 - Prob. 78PCh. 11.10 - Prob. 79PCh. 11.10 - What are the advantages and disadvantages of...Ch. 11.10 - Prob. 81PCh. 11.10 - Prob. 82PCh. 11.10 - An absorption refrigeration system that receives...Ch. 11.10 - An absorption refrigeration system receives heat...Ch. 11.10 - Heat is supplied to an absorption refrigeration...Ch. 11.10 - Prob. 86PCh. 11.10 - Prob. 87PCh. 11.10 - Prob. 88PCh. 11.10 - Prob. 89PCh. 11.10 - Consider a circular copper wire formed by...Ch. 11.10 - An iron wire and a constantan wire are formed into...Ch. 11.10 - Prob. 92PCh. 11.10 - Prob. 93PCh. 11.10 - Prob. 94PCh. 11.10 - Prob. 95PCh. 11.10 - Prob. 96PCh. 11.10 - Prob. 97PCh. 11.10 - Prob. 98PCh. 11.10 - A thermoelectric cooler has a COP of 0.18, and the...Ch. 11.10 - Prob. 100PCh. 11.10 - Prob. 101PCh. 11.10 - Prob. 102PCh. 11.10 - Prob. 103RPCh. 11.10 - Prob. 104RPCh. 11.10 - Prob. 105RPCh. 11.10 - A heat pump that operates on the ideal...Ch. 11.10 - A large refrigeration plant is to be maintained at...Ch. 11.10 - Repeat Prob. 11112 assuming the compressor has an...Ch. 11.10 - A heat pump operates on the ideal...Ch. 11.10 - An air conditioner with refrigerant-134a as the...Ch. 11.10 - An air conditioner operates on the...Ch. 11.10 - Consider a two-stage compression refrigeration...Ch. 11.10 - A two-evaporator compression refrigeration system...Ch. 11.10 - Prob. 116RPCh. 11.10 - Prob. 117RPCh. 11.10 - Prob. 118RPCh. 11.10 - Consider a regenerative gas refrigeration cycle...Ch. 11.10 - Prob. 120RPCh. 11.10 - The refrigeration system of Fig. P11122 is another...Ch. 11.10 - Repeat Prob. 11122 if the heat exchanger provides...Ch. 11.10 - An ideal gas refrigeration system with three...Ch. 11.10 - Derive a relation for the COP of the two-stage...Ch. 11.10 - Prob. 129FEPCh. 11.10 - Prob. 130FEPCh. 11.10 - Prob. 131FEPCh. 11.10 - Prob. 132FEPCh. 11.10 - An ideal vapor-compression refrigeration cycle...Ch. 11.10 - Prob. 134FEPCh. 11.10 - An ideal gas refrigeration cycle using air as the...Ch. 11.10 - Prob. 136FEPCh. 11.10 - Prob. 137FEPCh. 11.10 - Prob. 138FEP
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- Required information NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Consider a two-stage cascade refrigeration cycle with a flash chamber as shown in the figure with refrigerant-134a as the working fluid. The evaporator temperature is -10°C and the condenser pressure is 1600 kPa. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. Part of the refrigerant evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor. The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash chamber is throttled to the evaporator pressure and cools the refrigerated space as it vaporizes in the evaporator. The mass flow rate of the refrigerant through the low-pressure compressor is 0.11 kg/s. Assume that the refrigerant leaves the evaporator as a saturated vapor and…arrow_forwardThe required refrigeration capacity of a vapor compression refrigeration system (with R-22 as refrigerant) is 100 kW at –30oC evaporator temperature. Initially the system was single-stage with a single compressor compressing the refrigerant vapor from evaporator to a condenser operating at 1500 kPa pressure. Later the system was modified to a two- stage system operating on the cycle shown below. At the intermediate pressure of 600 kPa there is intercooling but no removal of flash gas. Find: a) Power requirement of the original single-stage system; b) Total power requirement of the two compressors in the revised two-stage system.arrow_forwardplease soonarrow_forward
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