Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 11.10, Problem 44P
The liquid leaving the condenser of a 100,000 Btu/h heat pump using refrigerant-134a as the working fluid is subcooled by 9.5°F. The condenser operates at 160 psia and the evaporator at 50 psia. How does this subcooling change the power required to drive the compressor as compared to an ideal vapor-compression refrigeration cycle?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
A heat pump operates on the ideal vapor-compression refrigeration cycle and uses refrigerant-134a as the working fluid. The
condenser operates at 1400 kPa and the evaporator at 140 kPa. Determine this system's COP and the rate of heat supplied to the
evaporator when the compressor consumes 7 kW.
(Take the required values from saturated refrigerant-134a tables.)
The COP of the system is
and the rate of heat supplied to the evaporator is
KM
4
A Carnot refrigeration cycle uses refrigerant-134a as the working fluid. The refrigerant evaporates at 120 kPa and condenses at 30ᵒC. The refrigerant changes from saturated vapor to saturated liquid in the condenser as it rejects heat. Determine the heat removal (kJ/kg) from the refrigerated space.
An air conditioner using refrigerant-134a as the working fluid and
operating on the ideal vapor-compression refrigeration cycle is to
maintain a space at 26°C while operating its condenser at 1400 kPa.
Determine the COP of the system when a temperature difference of
2°C is allowed for the transfer of heat in the evaporator. (Take the
required values from saturated refrigerant-134a tables.)
The COP of the system is
Chapter 11 Solutions
Thermodynamics: An Engineering Approach
Ch. 11.10 - Why do we study the reversed Carnot cycle even...Ch. 11.10 - Why is the reversed Carnot cycle executed within...Ch. 11.10 - A steady-flow Carnot refrigeration cycle uses...Ch. 11.10 - Refrigerant-134a enters the condenser of a...Ch. 11.10 - Does the ideal vapor-compression refrigeration...Ch. 11.10 - Why is the throttling valve not replaced by an...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 - It is proposed to use water instead of...
Ch. 11.10 - The COP of vapor-compression refrigeration cycles...Ch. 11.10 - A 10-kW cooling load is to be served by operating...Ch. 11.10 - An ice-making machine operates on the ideal...Ch. 11.10 - An air conditioner using refrigerant-134a as the...Ch. 11.10 - An ideal vapor-compression refrigeration cycle...Ch. 11.10 - A refrigerator operates on the ideal...Ch. 11.10 - A refrigerator uses refrigerant-134a as the...Ch. 11.10 - An ideal vapor-compression refrigeration cycle...Ch. 11.10 - A refrigerator uses refrigerant-134a as its...Ch. 11.10 - A refrigerator uses refrigerant-134a as the...Ch. 11.10 - A commercial refrigerator with refrigerant-134a as...Ch. 11.10 - The manufacturer of an air conditioner claims a...Ch. 11.10 - Prob. 24PCh. 11.10 - How is the second-law efficiency of a refrigerator...Ch. 11.10 - Prob. 26PCh. 11.10 - Prob. 27PCh. 11.10 - Prob. 28PCh. 11.10 - Bananas are to be cooled from 28C to 12C at a rate...Ch. 11.10 - A vapor-compression refrigeration system absorbs...Ch. 11.10 - A room is kept at 5C by a vapor-compression...Ch. 11.10 - Prob. 32PCh. 11.10 - A refrigerator operating on the vapor-compression...Ch. 11.10 - When selecting a refrigerant for a certain...Ch. 11.10 - A refrigerant-134a refrigerator is to maintain the...Ch. 11.10 - Consider a refrigeration system using...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 - A heat pump operates on the ideal...Ch. 11.10 - Refrigerant-134a enters the condenser of a...Ch. 11.10 - A heat pump that operates on the ideal...Ch. 11.10 - The liquid leaving the condenser of a 100,000...Ch. 11.10 - Reconsider Prob. 1144E. What is the effect on the...Ch. 11.10 - A heat pump using refrigerant-134a heats a house...Ch. 11.10 - A heat pump using refrigerant-134a as a...Ch. 11.10 - Reconsider Prob. 1148. What is the effect on the...Ch. 11.10 - Prob. 50PCh. 11.10 - How does the COP of a cascade refrigeration system...Ch. 11.10 - Consider a two-stage cascade refrigeration cycle...Ch. 11.10 - Can a vapor-compression refrigeration system with...Ch. 11.10 - Prob. 54PCh. 11.10 - A certain application requires maintaining the...Ch. 11.10 - Prob. 56PCh. 11.10 - Repeat Prob. 1156 for a flash chamber pressure of...Ch. 11.10 - Prob. 59PCh. 11.10 - A two-stage compression refrigeration system with...Ch. 11.10 - A two-stage compression refrigeration system with...Ch. 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 - Consider a two-stage cascade refrigeration cycle...Ch. 11.10 - How does the ideal gas refrigeration cycle differ...Ch. 11.10 - Prob. 67PCh. 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. 70PCh. 11.10 - How do we achieve very low temperatures with gas...Ch. 11.10 - An ideal gas refrigeration system operates with...Ch. 11.10 - Air enters the compressor of an ideal gas...Ch. 11.10 - Repeat Prob. 1173 for a compressor isentropic...Ch. 11.10 - An ideal gas refrigeration cycle uses air as the...Ch. 11.10 - Rework Prob. 1176E when the compressor isentropic...Ch. 11.10 - A gas refrigeration cycle with a pressure ratio of...Ch. 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. 81PCh. 11.10 - Prob. 82PCh. 11.10 - What are the advantages and disadvantages of...Ch. 11.10 - Prob. 84PCh. 11.10 - Prob. 85PCh. 11.10 - Prob. 86PCh. 11.10 - Prob. 87PCh. 11.10 - Heat is supplied to an absorption refrigeration...Ch. 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. 92PCh. 11.10 - Prob. 93PCh. 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. 96PCh. 11.10 - Prob. 97PCh. 11.10 - Prob. 98PCh. 11.10 - Prob. 99PCh. 11.10 - Prob. 100PCh. 11.10 - Prob. 101PCh. 11.10 - Prob. 102PCh. 11.10 - A thermoelectric cooler has a COP of 0.18, and the...Ch. 11.10 - Prob. 104PCh. 11.10 - Prob. 105PCh. 11.10 - Prob. 106PCh. 11.10 - Rooms with floor areas of up to 15 m2 are cooled...Ch. 11.10 - Consider a steady-flow Carnot refrigeration cycle...Ch. 11.10 - Consider an ice-producing plant that operates on...Ch. 11.10 - A heat pump that operates on the ideal...Ch. 11.10 - A heat pump 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 - An air conditioner with refrigerant-134a as the...Ch. 11.10 - A refrigerator using refrigerant-134a as the...Ch. 11.10 - Prob. 117RPCh. 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 - The refrigeration system of Fig. P11122 is another...Ch. 11.10 - Repeat Prob. 11122 if the heat exchanger provides...Ch. 11.10 - An aircraft on the ground is to be cooled by a gas...Ch. 11.10 - Consider a regenerative gas refrigeration cycle...Ch. 11.10 - An ideal gas refrigeration system with three...Ch. 11.10 - Prob. 130RPCh. 11.10 - Derive a relation for the COP of the two-stage...Ch. 11.10 - Prob. 133FEPCh. 11.10 - Prob. 134FEPCh. 11.10 - Prob. 135FEPCh. 11.10 - Prob. 136FEPCh. 11.10 - Prob. 137FEPCh. 11.10 - An ideal vapor-compression refrigeration cycle...Ch. 11.10 - Prob. 139FEPCh. 11.10 - An ideal gas refrigeration cycle using air as the...Ch. 11.10 - Prob. 141FEPCh. 11.10 - Prob. 142FEP
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Why is two-stage compression popular for extra-low-temperature refrigeration systems?arrow_forwardWhen a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be higher in temperature than the entering air temperature.arrow_forwardConsider a two-stage compression refrigeration system operating between the pressure limits of 0.8 and 0.14 MPa. The working fluid is refrigerant-134a. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.4 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 it cools the refrigerated space as it vaporizes in the evaporator. Assuming the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic, determine (a)the fraction of the refrigerant that evaporates as it is throttled to the flash chamber, (b)the amount of heat removed from the refrigerated space and the compressor work per unit mass of refrigerant flowing through the condenser,…arrow_forward
- An air conditioner using refrigant-134a as the working fluid and operating on the ideal vapor-compression refrigeration cycle is to maintain the cold space at 20degC while operating its condenser at 1.2 MPa. Determine the a. COP of the system when the evaporator's temperature is set at 18degC b. If the refrigerant leaves the compressor at 73degC at a rate of 4.85 kg/min, determine the rate of heat rejection to the environment (kW) c. isentropic efficiency of the compressor (%) and compressor power requirement (kW) Disregard any heat loss in the expansion valve and compressor as well as the change in potential and kinetic energy of the refrigerant in any part of the cycle.arrow_forwardA steady-flow Carnot refrigeration cycle uses R-134a as the working fluid. The refrigerant changes from saturated vapor to saturated liquid at 36°C in the condenser as it rejects heat. The evaporator pressure is 200 kPa. For every kg of refrigerant, calculate the amount of heat removed from the refrigerated spacearrow_forwardAn air conditioner using refrigerant-134a as the working fluid and operating on the ideal vapor-compression refrigeration cycle is to maintain a space at 36.00°C while operating its condenser at 1600 kPa. Determine the COP of the system when a temperature difference of 4.000°C is allowed for the transfer of heat in the evaporator. (Take the required values from saturated refrigerant-134a tables.) (Round the final answer to three decimal places.) The COP of the system isarrow_forward
- ai 10roh 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. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.32 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. Assuming the refrigerant leaves the evaporator as a saturated vapor and the isentropic efficiency is 85 percent for both compressors, determine (a) the mass flow rate of the refrigerant through the high-pressure compressor, (b) the rate of heat removal…arrow_forwardConsider a two-stage compression refrigeration system operating between the pressure limits of 0.8 and 0.14 MPa. The working fluid is refrigerant-134a. The refrigerant leaves the condenser as a saturated liquid and is throttled a flash chamber operating at 0.32 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. Assuming the refrigerant leaves the evaporator as a saturated vapor and both compressors are isentropic, determine (a) the fraction of the refrigerant that evaporates as it is throttled to the flash chamber, (b) the amount of heat removed from the refrigerated space and the compressor work per unit mass of refrigerant flowing through the condenser.arrow_forwardConsider 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. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.32 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. Assuming the refrigerant leaves the evaporator as a saturated vapor and the isentropic efficiency is 85 percent for both compressors, determine (a) the mass flow rate of the refrigerant through the high-pressure compressor, (b) the rate of heat removal from the…arrow_forward
- A two-evaporator, multiple EV,and single compression refrigeration system uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 0°C, evaporator 2 at -26.4°C, and the condenser at 800kPa. The refrigerant is circulated through the compressor at a rate of 0.1kg/s and the low temperature evaporator serves a cooling load of 8 kW.Determine the cooling rate of the high-temperature evaporator, the power required by the compressor, and the COP of the system. The refrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.arrow_forwardA vapor compression cycle with R-134a is being used as its refrigerant. The refrigerant leaves the evaporator at -10 C and 120 kPa and it enters the condenser 1.0 MPa. Assuming there is a heat loss due to compression which is equal to 20 kJ/kg, and it has a cooling capacity of 75 tons of refrigeration, Determine the following: (a)heat rejected (b)cooling effect (c)work of compression (d) coefficient of performance (e)volume flow rate of refrigerant (f)compressor discharge temperaturearrow_forwardI 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.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning
Refrigeration and Air Conditioning Technology (Mi...
Mechanical Engineering
ISBN:9781305578296
Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher:Cengage Learning
The Refrigeration Cycle Explained - The Four Major Components; Author: HVAC Know It All;https://www.youtube.com/watch?v=zfciSvOZDUY;License: Standard YouTube License, CC-BY