EBK THERMODYNAMICS: AN ENGINEERING APPR
8th Edition
ISBN: 8220100257056
Author: CENGEL
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 7.13, Problem 170RP
A refrigerator with a coefficient of performance of 4 transfers heat from a cold region at −20°C to a hot region at 30°C. Calculate the total entropy change of the regions when 1 kJ of heat is transferred from the cold region. Is the second law satisfied? Will this refrigerator still satisfy the second law if its coefficient of performance is 6?
FIGURE P7–168
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
An inventor claims that a new fridge can operate between -15 degree Celsius and 150 degree C while removing 2200 W of heat rate from the sink and using 2000 W of power. Use the concept of entropy generation to determine if this device violates the 2nd law of thermo or not
A rigid container with 6 m × 9 m × 3 m can be considered a closed system in which the container's initial
air pressure and temperature are 110 kPa and 32°C, respectively. A cooling coil is installed outside one of
the container walls (Figure Q1) to reduce the container's air temperature at a specified value. The cooling
coil removes 4500 J/s of heat from the container, and a 1000 W fan is supplied with electrical power to
distribute the cold air in the container. The container absorbs 1500 W heat from warmer outdoor due to heat
transfer through the walls. For air, take c, = 0.718 kJ/kg.K and R= 0.287 kJ/kg.K.
a) Find the mass of the air in the container (kg).
b) Determine the time required to reduce the container's air temperature to 24°C (minutes) and the
corresponding electrical power to operate the fan (kWh).
c) If the container's air is reduced to 26°C instead, determine the time required to accomplish
this (minutes) and the corresponding electrical power to operate the fan (kWh).…
A rigid tank contains air at 50°C that is being stirred by a paddle wheel. The paddle wheel does 350 kJ of work on the air (R=0.287 kJ/kgK, cv=0.718 kJ/kgK, and cp=1.005 kJ/kgK). It is observed that the temperature of air remains constant during this process as a result of heat transfer between the system and the surroundings at 22°C. The entropy generation for this process is
Chapter 7 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
Ch. 7.13 - Prob. 1PCh. 7.13 - Does the cyclic integral of heat have to be zero...Ch. 7.13 - Is a quantity whose cyclic integral is zero...Ch. 7.13 - Prob. 4PCh. 7.13 - Prob. 5PCh. 7.13 - How do the values of the integral 12Q/T compare...Ch. 7.13 - The entropy of a hot baked potato decreases as it...Ch. 7.13 - When a system is adiabatic, what can be said about...Ch. 7.13 - Prob. 9PCh. 7.13 - A pistoncylinder device contains helium gas....
Ch. 7.13 - A pistoncylinder device contains nitrogen gas....Ch. 7.13 - A pistoncylinder device contains superheated...Ch. 7.13 - The entropy of steam will (increase, decrease,...Ch. 7.13 - Prob. 14PCh. 7.13 - Prob. 15PCh. 7.13 - Prob. 16PCh. 7.13 - Steam is accelerated as it flows through an actual...Ch. 7.13 - Prob. 18PCh. 7.13 - Prob. 19PCh. 7.13 - Prob. 20PCh. 7.13 - Heat in the amount of 100 kJ is transferred...Ch. 7.13 - In Prob. 719, assume that the heat is transferred...Ch. 7.13 - 7–23 A completely reversible heat pump produces...Ch. 7.13 - During the isothermal heat addition process of a...Ch. 7.13 - Prob. 25PCh. 7.13 - During the isothermal heat rejection process of a...Ch. 7.13 - Prob. 27PCh. 7.13 - Prob. 28PCh. 7.13 - Two lbm of water at 300 psia fill a weighted...Ch. 7.13 - A well-insulated rigid tank contains 3 kg of a...Ch. 7.13 - The radiator of a steam heating system has a...Ch. 7.13 - A rigid tank is divided into two equal parts by a...Ch. 7.13 - 7–33 An insulated piston–cylinder device contains...Ch. 7.13 - Prob. 34PCh. 7.13 - Prob. 35PCh. 7.13 - Onekg of R-134a initially at 600 kPa and 25C...Ch. 7.13 - Refrigerant-134a is expanded isentropically from...Ch. 7.13 - Prob. 38PCh. 7.13 - Refrigerant-134a at 320 kPa and 40C undergoes an...Ch. 7.13 - A rigid tank contains 5 kg of saturated vapor...Ch. 7.13 - A 0.5-m3 rigid tank contains refrigerant-134a...Ch. 7.13 - Prob. 44PCh. 7.13 - Prob. 45PCh. 7.13 - Steam enters an adiabatic diffuser at 150 kPa and...Ch. 7.13 - Prob. 47PCh. 7.13 - An isentropic steam turbine processes 2 kg/s of...Ch. 7.13 - Prob. 50PCh. 7.13 -
7–51 0.7-kg of R-134a is expanded isentropically...Ch. 7.13 - Twokg of saturated water vapor at 600 kPa are...Ch. 7.13 - Steam enters a steady-flow adiabatic nozzle with a...Ch. 7.13 - Prob. 54PCh. 7.13 - In Prob. 755, the water is stirred at the same...Ch. 7.13 - A pistoncylinder device contains 5 kg of steam at...Ch. 7.13 - Prob. 57PCh. 7.13 - Prob. 59PCh. 7.13 - A 50-kg copper block initially at 140C is dropped...Ch. 7.13 - Prob. 61PCh. 7.13 - Prob. 62PCh. 7.13 - A 30-kg aluminum block initially at 140C is...Ch. 7.13 - A 30-kg iron block and a 40-kg copper block, both...Ch. 7.13 - An adiabatic pump is to be used to compress...Ch. 7.13 - Prob. 67PCh. 7.13 - Can the entropy of an ideal gas change during an...Ch. 7.13 - An ideal gas undergoes a process between two...Ch. 7.13 - Prob. 72PCh. 7.13 - Prob. 73PCh. 7.13 - Prob. 74PCh. 7.13 - Prob. 75PCh. 7.13 - A 1.5-m3 insulated rigid tank contains 2.7 kg of...Ch. 7.13 - An insulated pistoncylinder device initially...Ch. 7.13 - A pistoncylinder device contains 0.75 kg of...Ch. 7.13 - Prob. 80PCh. 7.13 - 7–81 Air enters a nozzle steadily at 280 kPa and...Ch. 7.13 - A mass of 25 lbm of helium undergoes a process...Ch. 7.13 - One kg of air at 200 kPa and 127C is contained in...Ch. 7.13 - Prob. 85PCh. 7.13 - Air at 3.5 MPa and 500C is expanded in an...Ch. 7.13 -
7–87E Air is compressed in an isentropic...Ch. 7.13 - An insulated rigid tank is divided into two equal...Ch. 7.13 - An insulated rigid tank contains 4 kg of argon gas...Ch. 7.13 - Prob. 90PCh. 7.13 - Prob. 91PCh. 7.13 - Prob. 92PCh. 7.13 - Air at 27C and 100 kPa is contained in a...Ch. 7.13 - Prob. 94PCh. 7.13 - Helium gas is compressed from 90 kPa and 30C to...Ch. 7.13 - Five kg of air at 427C and 600 kPa are contained...Ch. 7.13 - Prob. 97PCh. 7.13 - The well-insulated container shown in Fig. P 795E...Ch. 7.13 - Prob. 99PCh. 7.13 - Prob. 100PCh. 7.13 - It is well known that the power consumed by a...Ch. 7.13 - Prob. 102PCh. 7.13 - Prob. 103PCh. 7.13 - Saturated water vapor at 150C is compressed in a...Ch. 7.13 - Liquid water at 120 kPa enters a 7-kW pump where...Ch. 7.13 - Prob. 106PCh. 7.13 - Consider a steam power plant that operates between...Ch. 7.13 - Helium gas is compressed from 16 psia and 85F to...Ch. 7.13 - Nitrogen gas is compressed from 80 kPa and 27C to...Ch. 7.13 - Saturated refrigerant-134a vapor at 15 psia is...Ch. 7.13 - Describe the ideal process for an (a) adiabatic...Ch. 7.13 - Is the isentropic process a suitable model for...Ch. 7.13 - On a T-s diagram, does the actual exit state...Ch. 7.13 - Steam at 100 psia and 650F is expanded...Ch. 7.13 - Prob. 117PCh. 7.13 - Combustion gases enter an adiabatic gas turbine at...Ch. 7.13 - Steam at 4 MPa and 350C is expanded in an...Ch. 7.13 - Prob. 120PCh. 7.13 - Prob. 122PCh. 7.13 - Prob. 123PCh. 7.13 - Refrigerant-134a enters an adiabatic compressor as...Ch. 7.13 - Prob. 126PCh. 7.13 - Argon gas enters an adiabatic compressor at 14...Ch. 7.13 - Air enters an adiabatic nozzle at 45 psia and 940F...Ch. 7.13 - Prob. 130PCh. 7.13 - An adiabatic diffuser at the inlet of a jet engine...Ch. 7.13 - Hot combustion gases enter the nozzle of a...Ch. 7.13 - Refrigerant-134a is expanded adiabatically from...Ch. 7.13 - Oxygen enters an insulated 12-cm-diameter pipe...Ch. 7.13 - Prob. 135PCh. 7.13 - Prob. 136PCh. 7.13 - Steam enters an adiabatic turbine steadily at 7...Ch. 7.13 - 7–138 In an ice-making plant, water at 0°C is...Ch. 7.13 - Water at 20 psia and 50F enters a mixing chamber...Ch. 7.13 - Prob. 140PCh. 7.13 - Prob. 141PCh. 7.13 - Prob. 142PCh. 7.13 - Prob. 143PCh. 7.13 - In a dairy plant, milk at 4C is pasteurized...Ch. 7.13 - An ordinary egg can be approximated as a...Ch. 7.13 - Prob. 146PCh. 7.13 - Prob. 147PCh. 7.13 - In a production facility, 1.2-in-thick, 2-ft 2-ft...Ch. 7.13 - Prob. 149PCh. 7.13 - Prob. 150PCh. 7.13 - A frictionless pistoncylinder device contains...Ch. 7.13 - Prob. 152PCh. 7.13 - Prob. 153PCh. 7.13 - Prob. 154PCh. 7.13 - Prob. 155PCh. 7.13 - Liquid water at 200 kPa and 15C is heated in a...Ch. 7.13 - Prob. 157PCh. 7.13 - Prob. 158PCh. 7.13 - Prob. 159PCh. 7.13 - Prob. 160PCh. 7.13 - Prob. 161PCh. 7.13 - Prob. 162PCh. 7.13 - Prob. 163PCh. 7.13 - Prob. 164PCh. 7.13 - Prob. 165PCh. 7.13 - The space heating of a facility is accomplished by...Ch. 7.13 - Prob. 167PCh. 7.13 - Prob. 168PCh. 7.13 - Prob. 169RPCh. 7.13 - A refrigerator with a coefficient of performance...Ch. 7.13 - Prob. 171RPCh. 7.13 - Prob. 172RPCh. 7.13 - Prob. 173RPCh. 7.13 - A 100-lbm block of a solid material whose specific...Ch. 7.13 - Prob. 175RPCh. 7.13 - Prob. 176RPCh. 7.13 - A pistoncylinder device initially contains 15 ft3...Ch. 7.13 - Prob. 178RPCh. 7.13 - A 0.8-m3 rigid tank contains carbon dioxide (CO2)...Ch. 7.13 - Helium gas is throttled steadily from 400 kPa and...Ch. 7.13 - Air enters the evaporator section of a window air...Ch. 7.13 - Refrigerant-134a enters a compressor as a...Ch. 7.13 - Prob. 183RPCh. 7.13 - Three kg of helium gas at 100 kPa and 27C are...Ch. 7.13 - Prob. 185RPCh. 7.13 -
7–186 You are to expand a gas adiabatically from...Ch. 7.13 - Prob. 187RPCh. 7.13 - Determine the work input and entropy generation...Ch. 7.13 - Prob. 189RPCh. 7.13 - Prob. 190RPCh. 7.13 - Air enters a two-stage compressor at 100 kPa and...Ch. 7.13 - Steam at 6 MPa and 500C enters a two-stage...Ch. 7.13 - Prob. 193RPCh. 7.13 - Prob. 194RPCh. 7.13 - Prob. 196RPCh. 7.13 - Prob. 197RPCh. 7.13 - 7–198 To control the power output of an isentropic...Ch. 7.13 - Prob. 199RPCh. 7.13 - Prob. 200RPCh. 7.13 - A 5-ft3 rigid tank initially contains...Ch. 7.13 - Prob. 202RPCh. 7.13 - Prob. 203RPCh. 7.13 - Prob. 204RPCh. 7.13 - Prob. 205RPCh. 7.13 - Prob. 206RPCh. 7.13 - Prob. 207RPCh. 7.13 - Prob. 208RPCh. 7.13 - (a) Water flows through a shower head steadily at...Ch. 7.13 - Prob. 211RPCh. 7.13 - Prob. 212RPCh. 7.13 - Prob. 213RPCh. 7.13 - Consider the turbocharger of an internal...Ch. 7.13 - Prob. 215RPCh. 7.13 - Prob. 216RPCh. 7.13 - Prob. 217RPCh. 7.13 - Consider two bodies of identical mass m and...Ch. 7.13 - Prob. 220RPCh. 7.13 - Prob. 222RPCh. 7.13 - Prob. 224RPCh. 7.13 - The polytropic or small stage efficiency of a...Ch. 7.13 - Steam is compressed from 6 MPa and 300C to 10 MPa...Ch. 7.13 - An apple with a mass of 0.12 kg and average...Ch. 7.13 - A pistoncylinder device contains 5 kg of saturated...Ch. 7.13 - Prob. 229FEPCh. 7.13 - Prob. 230FEPCh. 7.13 - A unit mass of a substance undergoes an...Ch. 7.13 - A unit mass of an ideal gas at temperature T...Ch. 7.13 - Prob. 233FEPCh. 7.13 - Prob. 234FEPCh. 7.13 - Air is compressed steadily and adiabatically from...Ch. 7.13 - Argon gas expands in an adiabatic turbine steadily...Ch. 7.13 - Water enters a pump steadily at 100 kPa at a rate...Ch. 7.13 - Air is to be compressed steadily and...Ch. 7.13 - Helium gas enters an adiabatic nozzle steadily at...Ch. 7.13 - Combustion gases with a specific heat ratio of 1.3...Ch. 7.13 - Steam enters an adiabatic turbine steadily at 400C...Ch. 7.13 - Liquid water enters an adiabatic piping system at...Ch. 7.13 - Prob. 243FEPCh. 7.13 - Steam enters an adiabatic turbine at 8 MPa and...Ch. 7.13 - Helium gas is compressed steadily from 90 kPa and...
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
- A rigid tank contains air at 40°C that is being stirred by a paddle wheel. The paddle wheel does 400 kJ of work on the air (R=0.287 kJ/kgK, cv=0.718 kJ/kgK, and cp=1.005 kJ/kgK). It is observed that the temperature of the air remains constant during this process as a result of heat transfer between the system and the surroundings at 30°C. The entropy generation for this process isarrow_forwardAn inventor proposes to make a heat engine using water/ice as the working substance, taking advantage of the fact that water expands as it freezes. A weight to be lifted is placed on top of a piston over a cylinder of water at 1°C. The system is then placed in thermal contact with a low-temperature reservoir at -1°C until the water freezes into ice, lifting the weight. The weight is then removed and the ice is melted by putting it in contact with a high-temperature reservoir at 1°C. The inventor is pleased with this device because it can seemingly perform an unlimited amount of work while absorbing only a finite amount of heat. Explain the flaw in the inventor's reasoning, and use the Clausius-Clapeyron relation to prove that the maximum efficiency of this engine is still given by the Carnot formula, 1 -Tc/Th.arrow_forwardHeat flows through a wall at a rate of 3x 10° kJ/hr. The temperatures of two faces of the wall are 327° C and 207°C. If the surroundings are at 27°C. What is the loss in available energy?arrow_forward
- The power required to drive the compressor in a Carnot refrigerator is 48 hp. It operates between -6°C and 39°C. Determine the coefficient of performance.arrow_forwardA heat pump can use a maximum of 2 kW power for maintaining a house at 20°C during winter. The rate of heat transfer from the roof and walls is 3000 kJ/h per degree temperature difference between inside and outside. The coefficient of performance is 25% of a reversible heat pump. Determine the minimum outside temperature for which the heat pump can meet the heating requirements of the house.arrow_forwardTHERMOFLUID A 4-in X 5-m X 7-m room is heated by the radiator of a steam-heating system. The steam radiator transfers heat at a rate of 10.000 kJ/h, and a 100-W fan is used to distribute the warm air in the room. The rate of heat loss from the room is estimated to be about 5000 kJ/h. If the initial temperature of the room air is 10°C, determine how long it will take for the air temperature to rise to 20°C, Assume constant specific heats at room temperature.arrow_forward
- 3- A 5-m x 6-m x 8-m room is to be heated by an electrical resistance heater placed in a short duct in the room. Initially, the room is at 15°C, and the local atmospheric pressure is 98 kPa. The room is losing heat steadily to the outside at a rate of 200 kJ/min. A 200-W fan circulates the air steadily through the duct and the electric heater at an average mass flow rate of 50 kg/min. The duct can be assumed to be adiabatic, and there is no air leaking in or out of the room. If it takes 15 minutes for the room air to reach an average temperature of 25°C, find (a) the power rating of the electric heater and (b) the temperature rise that the air experiences each time it passes through the heater.arrow_forwardA house loses heat through its exterior at a rate of 5 kW when the inside temperature is 22◦C and the outside temperature is −5◦C. Determine the electrical power required to maintain the interior temperature at 22◦C for the following two cases: (a) The electrical power is used in resistance heaters that convert all the power to heat. (b) The electrical power is used to drive the motor of a heat pump that has a coefficient of performance equal to 30% of the Carnot cycle value.arrow_forwardA heat engine receives heat from a source at 1100 K at a rate of 400 kJ/s, and it rejects the waste heat to a medium at 320 K. The measured power output of the heat engine is 120 kW, and the environment temperature is 25°C.Determine the reversible power.arrow_forward
- A refrigerator is removing heat from a cold medium at 3°C at a rate of 7200 kJ/h and rejecting the waste heat to a medium at 30°C. If the coefficient of performance of the refrigerator is 2, the power consumed by the refrigerator amounts to kW (round off to 2 decimal places). The maximum COP of the refrigerator is (round off to 2 decimal places), if the processes that occurred were reversible.arrow_forwardA steady flow thermodynamic system receives 100 lb/min of a fluid at 30 psia and 200°F and discharges it from a point 80 ft above the entrance section at 150 psia and 600°F. The fluid enters with a velocity of 7200 fpm and leaves with a velocity of 2400 fpm. During this process, there are supplied 25,000 Btu/hr of heat from an external source, and the increase in enthalpy is 2.0 Btu/lb. Determine the work done.A. 5.48 HpB. 6.20 HpC. 7.15 HpD. 8.08 Hparrow_forwardConsider steady heat transfer through a 5-m × 7-m brick wall of a house of thickness 30 cm. On a day when the temperature of the outdoors is 0°C, the house is maintained at 27°C. The temperatures of the inner and outer surfaces of the brick wall are measured to be 20°C and 5°C, respectively, and the rate of heat transfer through the wall is 1035 W. Determine the rate of entropy generation in the wall and the rate of total entropy generation associated with this heat transfer process.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
What is entropy? - Jeff Phillips; Author: TED-Ed;https://www.youtube.com/watch?v=YM-uykVfq_E;License: Standard youtube license