Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781260048766
Author: CENGEL
Publisher: MCG
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 11.10, Problem 60P
A two-stage compression refrigeration system with an adiabatic liquid-vapor separation unit as shown in Fig. P11–60 uses refrigerant-134a as the working fluid. The system operates the evaporator at −40°C, the condenser at 800 kPa, and the separator at −10.1°C. This system is to serve a 30-kW cooling load. Determine the mass flow rate through each of the two compressors, the power used by the compressors, and the system’s COP. The refrigerant is saturated liquid at the inlet of each expansion valve and saturated vapor at the inlet of each compressor, and the compressors are isentropic.
FIGURE P11–60
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
An ideal vapor-compression refrigeration cycle using refrigerant-134a as the working fluid is used to cool a brine solution to
-5°C. This solution is pumped to various buildings for the purpose of air-conditioning. The refrigerant evaporates at -18°C with a
total mass flow rate of 5 kg/s and condenses at 600 kPa. Determine the COP of the cycle and the total cooling load. (Take the
required values from saturated refrigerant-134a tables.)
The COP of the cycle is
, and the total cooling load is
kW.
An ideal vapor-compression refrigeration cycle using refrigerant-134a as the working fluid is used to cool a brine solution to -5°C. This
solution is pumped to various buildings for the purpose of air-conditioning. The refrigerant evaporates at -12.00°C with a total mass
flow rate of 8.000 kg/s and condenses at 600 kPa. Determine the COP of the cycle and the total cooling load. (Take the required
values from saturated refrigerant-134a tables.)
The COP of the cycle is
(Round the final answer to three decimal places.) and the total cooling load is
kW.
A 12 kW cooling load is to be served by operating an ideal vapor-compression refrigeration cycle with its evaporator at 240 kPa and its
condenser at 800 kPa. Calculate the refrigerant mass flow rate and the compressor power requirement when refrigerant-134a is used.
(Take the required values from the saturated refrigerant-134a tables.)
The refrigerant mass flow rate is
The compressor power requirement is
kg/s.
KW.
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
- Condensers in these refrigerators are all_______cooled.arrow_forwardA two-evaporator compression refrigeration system as shown in Fig. P11–120E uses refrigerant-134a as theworking fluid. The system operates evaporator 1 at 30°F, evaporator 2 at −29.5°F, and the condenser at 160 psia. The cooling load of evaporator 1 is double that of evaporator 2. Determine the cooling load of both evaporators per unit of flow through the compressor, as well as the COP of this 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.Reconsider Prob. 11–120E. The refrigeration system of that problem cools one reservoir at −15°F and one at40°F while rejecting heat to a reservoir at 80°F. Which processhas the highest exergy destruction?arrow_forward2. A cascade refrigeration system using R - 22 in the low - temperature circuit and ammonia (R-717) in the high - temperature circuit has a load of 150 kW. The low - temperature circuit operates at an evaporating temperature of -50°C and a condensing pressure of 500 kPa. Refrigerant leaves the low temperature evaporator as saturated vapor and enters the suction of the low - temperature compressor at - 45°C. Liquid refrigerant exits the condenser at 02°C. The high temperature circuit - operates at an evaporating temperature of -10°C and a condensing pressure of 1200 kPa. The refrigerant exits both evaporator and condenser at saturated conditions. Calculate the power input to the high temperature circuit - compressor, kW.arrow_forward
- Thermodynamicsarrow_forwardA two-evaporator compression refrigeration system as shown in the figure 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 800 kPa. The refrigerant is circulated through the compressor at a rate of 0.1 kg/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 a saturated liquid at the exit of the condenser and a saturated vapor at the exit of each evaporator, and the compressor is isentropic. The pressure reducing valve drops the pressure of the evaporator 1 discharge to evaporator 2 discharge pressure. (Take the required values from saturated refrigerant-134a tables.) 1 ↑ 7 Pressure reducing valve m₁ + m₂ Condenser m₁ Evaporator 1 Evaporator 2 m₂ S The cooling rate of the high-temperature evaporator is of the system is 3 kW, the power required by…arrow_forwardA two-evaporatoor compression refrigeration system like that in the Figure below uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 30 psia, evaporator 2 at 10 psia, and the condeser at 180 psia. The cooling load for evaporator 1 is 9000 Btu/h and that for evaporator 2 is 24,000 Btu/h. Determine the power required to operate the compressor and the COP of this system. The regrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.arrow_forward
- A vapor-compression system produces 20 tons of refrigeration using R12 as a refrigerant while operating between a condenser temperature of 41.6°c and an evaporator temperature of – 25°c. The superheat at the compression suction and the sub-cooling at the condenser outlet are 10°K. The pressure drop are 10kPa across the evaporator and the condenser. Determine the refrigerating effect in kJ per kilogram, the circulating rate of R12 in kilograms per second, the power required, the COP, the heat rejected in kW and the volume flow rate of refrigerant at compressor inlet conditions. 10° K subcooling 4 Tm= 41.6° C h= C s =C Tevap =-25° C 10° K superheatarrow_forwardDetermine the cooling capacity and the coefficient of performance of the air conditioning system?arrow_forwardA food storage locker requires a refrigeration system of 2,400 kJ/min capacity at an evaporator temperature of -10OC and a condenser temperature of 30OC. The refrigerant used is freon-12 and sub-cooled by 6OC before entering the expansion valve and vapor is superheated by 7OC before leaving the evaporator coil. The compression of refrigerant is isentropic. The refrigeration compressor is two-cylinder, single-acting with stroke equal to 1.25 times the bore diameter and operates at 1000 rpm. Determine: (a) refrigerating effect, (b) mass of refrigerant to be circulated, (c) theoretical piston displacement per minute, (d) theoretical power to run the compressor in kW, (e) heat removed from the condenser per min. (f) theoretical bore and stroke of compressor.arrow_forward
- 1. An ideal vapor-compression refrigeration cycle that uses refrigerant-134a as its working fluid maintains a condenser at 800 kPa and the evaporator at -12°C. Determine this system's COP and the amount of power required to service a 150 kW cooling load. Answers: 4.87, 30.8 kWarrow_forwardA two-stage compression refrigeration system operates with refrigerant-134a between the pressure limits of 1.4 MPa and 0.10 MPa. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.6 MPa. he flash chamber is maintained at the same pressure as the low pressure discharge which is 0.6 Mpa. The vapor in the flash chamber is then compressed to the condenser pressure by the high-pressure compressor, and the liquid is throttled to the evaporator pressure. Assume the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic. Consider a mass flow rate of 0.19 kg/s through the condenser. (Take the required values from saturated refrigerant-134a tables.) Determine the fraction of the refrigerant that evaporates as it is throttled to the flash chamber. (You must provide an answer before moving to the next part.) The fraction of the refrigerant that evaporates as it is throttled to the flash chamber is…arrow_forwardA two-stage compression refrigeration system operates with refrigerant-134a between the pressure limits of 1.4 MPa and 0.10 MPa. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.6 MPa. he flash chamber is maintained at the same pressure as the low pressure discharge which is 0.6 Mpa. The vapor in the flash chamber is then compressed to the condenser pressure by the high-pressure compressor, and the liquid is throttled to the evaporator pressure. Assume the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic. Consider a mass flow rate of 0.19 kg/s through the condenser. (Take the required values from saturated refrigerant-134a tables.) Determine the coefficient of performance. The coefficient of performance is ______.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