EBK THERMODYNAMICS: AN ENGINEERING APPR
9th Edition
ISBN: 8220106796979
Author: CENGEL
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 11.10, Problem 122RP
The refrigeration system of Fig. P11–122 is another variation of the basic vapor-compression refrigeration system which attempts to reduce the compression work. In this system, a heat exchanger is used to superheat the vapor entering the compressor while subcooling the liquid exiting from the condenser. Consider a system of this type that uses refrigerant-134a as its refrigerant and operates the evaporator at −10.09°C and the condenser at 900 kPa. Determine the system COP when the heat exchanger provides 5.51°C of subcooling at the throttle valve entrance. Assume the refrigerant leaves the evaporator as a saturated vapor and the compressor is isentropic.
FIGURE P11–122
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
A 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.
A two stage cascade refrigeration system uses R-12 in the high pressure loop with a condenser temperature of 300C and -100C in the cascade condenser, and R-22 in the low pressure loop with a temperature in the cascade condenser of 00C and an evaporator temperature of -30 0C. Given that, h6 = 366 kJ/kg; h2= 421 kJ/kg. Determine the amount of ice (kg)for a 10 hrs operation if the initial temp of water is 31 0C to ice at --80C. ANSWER: 7358.9169 kg
A two stage cascade refrigeration system uses R-11 as the working substance. The evaporator is at -30 0C and the high pressure condenser is at 300C. The cascade condenser is a direct contact type. The refrigeration load is 24 tons. Given that, h2 = 393 kJ/kg; h6 = 408 kJ/kg. Determine the ff:
a.) amount ofwater for a 10 hrs operation if the initial temp of water is 34 0C to 20C.
ANSWER: 22656.8019kg
b.) amount of cooling water needed for a temp rise of 130C.
ANSWER: 1.9446
c.) heat…
2. 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.
Chapter 11 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
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_forwardWhen a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be higher in temperature than the entering air temperature.arrow_forwardRefrigerators currently being manufactured in the United States are using______as their refrigerant.arrow_forward
- What are the approximate temperature ranges tor low-, medium-, and high-temperature refrigeration applications?arrow_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 Single Stage Vapor Compression (SSVC) refrigeration system has a cooling capacity of 7.5 tons. The following are the actual conditions: discharge of the evaporator is at -30°C & 0.2 MPa, discharge of the condenser is at 30°C & 2.0 MPa, discharge of the compressor is at 130°C & 2.5 MPa. Determine the Energy Efficiency Ratio in kJ/hr/Warrow_forward
- Determine the degrees of subcooling at the exit of the condenser of a 2-ton air-conditioner system. The system operates on the ideal, vapor-compression refrigerationcycle with the following design parameters: R-134a flow rate 0.05 kg/s Evaporator Pressure 200 kPa Condenser Pressure 1200 kPaarrow_forwardAn R-12 refrigeration system using a single compressor serves three evaporators of 50, 30 and 20 tons capacity in parallel to each other with an evaporating temperatures of 0 C(hg = 351.447 KJ/kg), -5 C(hg = 349.321 KJ/kg) and -10 C(hg = 347.134 KJ/kg), respectively. If the condenser is maintained at 40 C(hf = 238.535 KJ/kg), compute the COP of the system. Enthalpy at the end of compression is at 378 KJ/kg.arrow_forward1. 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_forward
- 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.arrow_forwardA simple saturated refrigeration cycle for R-12 system operates at an evaporating temperature of-5C and a condensing temperature of 40℃.For refrigerating capacity of 30 kw, determine the work of the compressor. At 40°℃,hf=238.5 kJ/kg;at-5C,hg =349.3 kJ/kg,.Enthalpy entrance to the condenser is 372 kJ/kg.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
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