EBK THERMODYNAMICS: AN ENGINEERING APPR
8th Edition
ISBN: 8220102809444
Author: CENGEL
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 8.8, Problem 129RP
Water enters a pump at 100 kPa and 30°C at a rate of 1.35 kg/s and leaves at 4 MPa. If the pump has an isentropic efficiency of 70 percent, determine (a) the actual power input, (b) the rate of frictional heating, (c) the exergy destruction, and (d) the second-law efficiency for an environment temperature of 20°C.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
Consider a family of four, with each person taking a 6-min shower every morning. The average flow rate through the shower head is 10 L/min. City water at 15°C is heated to 55°C in an electric water heater and tempered to 42°C by cold water at the T-elbow of the shower before being routed to the shower head. Determine the amount of exergy destroyed by this family per year as a result of taking daily showers. Take T0 = 25°C.
A heat pump unit operates between two heat reservoirs with temperatures of 270
and 330 K. The heat pump itself has a temperature of 255 K during heat addition
from the 270 K reservoir and a temperature of 350K during heat rejection to the
330 K reservoir. The COP of the actual unit is 3.40, and the heat-transfer rate
from the 270 K reservoir is 2000 kJ/min. Determine the entropy production rate, in
kJ/min · K, for
a. the heat pump unit itself
b. the low-temperature heat-transfer process
c. the high-temperature heat-transfer process
d. Which process has the largest irreversibility?
Now, for the same temperatures and a heat-transfer rate of 2000 kJ/min, reduce the
actual COP to 3.10. Again, determine the entropy production rate for
e. the refrigeration unit itself
f. the low-temperature heat-transfer process
g. the high-temperature heat-transfer process
h. Which process now has the largest irreversibility?
Refrigerant-134a is condensed in a refrigeration system by rejecting heat to ambient air at 25°C. R-134a enters the condenser at 700 kPa and 50°C at a rate of 0.05 kg/s and leaves at the same pressure as a saturated liquid. Determine the rate of exergy destruction in the condenser.
Chapter 8 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
Ch. 8.8 - What final state will maximize the work output of...Ch. 8.8 - Is the exergy of a system different in different...Ch. 8.8 - How does useful work differ from actual work? For...Ch. 8.8 - Prob. 4PCh. 8.8 - Consider two geothermal wells whose energy...Ch. 8.8 - Consider two systems that are at the same pressure...Ch. 8.8 - Prob. 7PCh. 8.8 - Does a power plant that has a higher thermal...Ch. 8.8 - Prob. 9PCh. 8.8 - 8–10C Can a process for which the reversible work...
Ch. 8.8 - 8–11C Consider a process during which no entropy...Ch. 8.8 - Prob. 12PCh. 8.8 - 8–13E Saturated stem is generated in a boiler by...Ch. 8.8 - One method of meeting the extra electric power...Ch. 8.8 - Prob. 15PCh. 8.8 - A heat engine that receives heat from a furnace at...Ch. 8.8 - Consider a thermal energy reservoir at 1500 K that...Ch. 8.8 - A heat engine receives heat from a source at 1100...Ch. 8.8 - A heat engine that rejects waste heat to a sink at...Ch. 8.8 - Prob. 21PCh. 8.8 - A freezer is maintained at 20F by removing heat...Ch. 8.8 - Prob. 23PCh. 8.8 - Can a system have a higher second-law efficiency...Ch. 8.8 - A mass of 8 kg of helium undergoes a process from...Ch. 8.8 - Prob. 26PCh. 8.8 - Which is a more valuable resource for work...Ch. 8.8 - Which has the capability to produce the most work...Ch. 8.8 - A pistoncylinder device contains 8 kg of...Ch. 8.8 - The radiator of a steam heating system has a...Ch. 8.8 - A well-insulated rigid tank contains 6 lbm of a...Ch. 8.8 - Prob. 33PCh. 8.8 - Prob. 35PCh. 8.8 - Prob. 36PCh. 8.8 - A pistoncylinder device initially contains 2 L of...Ch. 8.8 - A 0.8-m3 insulated rigid tank contains 1.54 kg of...Ch. 8.8 - An insulated pistoncylinder device initially...Ch. 8.8 - An insulated rigid tank is divided into two equal...Ch. 8.8 - Prob. 41PCh. 8.8 - Prob. 42PCh. 8.8 - Prob. 43PCh. 8.8 - Prob. 44PCh. 8.8 - Prob. 45PCh. 8.8 - Prob. 46PCh. 8.8 - A pistoncylinder device initially contains 1.4 kg...Ch. 8.8 - Prob. 48PCh. 8.8 - Prob. 50PCh. 8.8 - Prob. 51PCh. 8.8 - Air enters a nozzle steadily at 200 kPa and 65C...Ch. 8.8 - Prob. 55PCh. 8.8 - Prob. 56PCh. 8.8 - Argon gas enters an adiabatic compressor at 120...Ch. 8.8 - Prob. 58PCh. 8.8 - Prob. 59PCh. 8.8 - Prob. 60PCh. 8.8 - Combustion gases enter a gas turbine at 900C, 800...Ch. 8.8 - Prob. 62PCh. 8.8 - Refrigerant-134a is condensed in a refrigeration...Ch. 8.8 - Prob. 64PCh. 8.8 - Refrigerant-22 absorbs heat from a cooled space at...Ch. 8.8 - Prob. 66PCh. 8.8 - Prob. 67PCh. 8.8 - Prob. 68PCh. 8.8 - Prob. 69PCh. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Hot combustion gases enter the nozzle of a...Ch. 8.8 - Prob. 72PCh. 8.8 - Prob. 73PCh. 8.8 - Prob. 74PCh. 8.8 - Prob. 75PCh. 8.8 - Prob. 76PCh. 8.8 - Prob. 77PCh. 8.8 - An insulated vertical pistoncylinder device...Ch. 8.8 - Prob. 79PCh. 8.8 - Prob. 80PCh. 8.8 - Prob. 81PCh. 8.8 - Steam is to be condensed on the shell side of a...Ch. 8.8 - 8–83 Air enters a compressor at ambient conditions...Ch. 8.8 - Prob. 84PCh. 8.8 - Prob. 85PCh. 8.8 - Prob. 86RPCh. 8.8 - Prob. 87RPCh. 8.8 - Steam enters an adiabatic nozzle at 3.5 MPa and...Ch. 8.8 - Prob. 89RPCh. 8.8 - Prob. 91RPCh. 8.8 - A well-insulated, thin-walled, counterflow heat...Ch. 8.8 - Prob. 93RPCh. 8.8 - Prob. 94RPCh. 8.8 - Prob. 95RPCh. 8.8 - Prob. 96RPCh. 8.8 - Prob. 97RPCh. 8.8 - Prob. 98RPCh. 8.8 - Prob. 99RPCh. 8.8 - Prob. 100RPCh. 8.8 - Prob. 101RPCh. 8.8 - A pistoncylinder device initially contains 8 ft3...Ch. 8.8 - Steam at 7 MPa and 400C enters a two-stage...Ch. 8.8 - Steam enters a two-stage adiabatic turbine at 8...Ch. 8.8 - Prob. 105RPCh. 8.8 - Prob. 106RPCh. 8.8 - Prob. 107RPCh. 8.8 - Prob. 108RPCh. 8.8 - Prob. 109RPCh. 8.8 - Prob. 111RPCh. 8.8 - Prob. 112RPCh. 8.8 - A passive solar house that was losing heat to the...Ch. 8.8 - Prob. 114RPCh. 8.8 - Prob. 115RPCh. 8.8 - Prob. 116RPCh. 8.8 - Prob. 117RPCh. 8.8 - Prob. 118RPCh. 8.8 - A 4-L pressure cooker has an operating pressure of...Ch. 8.8 - Repeat Prob. 8114 if heat were supplied to the...Ch. 8.8 - Prob. 121RPCh. 8.8 - Prob. 122RPCh. 8.8 - Reconsider Prob. 8-120. The air stored in the tank...Ch. 8.8 - Prob. 124RPCh. 8.8 - Prob. 125RPCh. 8.8 - Prob. 126RPCh. 8.8 - Prob. 127RPCh. 8.8 - Prob. 128RPCh. 8.8 - Water enters a pump at 100 kPa and 30C at a rate...Ch. 8.8 - Prob. 130RPCh. 8.8 - Nitrogen gas enters a diffuser at 100 kPa and 110C...Ch. 8.8 - Obtain a relation for the second-law efficiency of...Ch. 8.8 - Writing the first- and second-law relations and...Ch. 8.8 - Prob. 134RPCh. 8.8 - Prob. 136FEPCh. 8.8 - Prob. 137FEPCh. 8.8 - A heat engine receives heat from a source at 1500...Ch. 8.8 - Prob. 139FEPCh. 8.8 - Prob. 140FEPCh. 8.8 - A 12-kg solid whose specific heat is 2.8 kJ/kgC is...Ch. 8.8 - Keeping the limitations imposed by the second law...Ch. 8.8 - A furnace can supply heat steadily at 1300 K at a...Ch. 8.8 - Air is throttled from 50C and 800 kPa to a...Ch. 8.8 - Prob. 145FEP
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
- Water enters a pump at environmental conditions, 100 kPa and 20°C at a rate of 1.5kg/s and leaves at 5 MPa. The pump has an isentropic efficiency of 80 percent,determine(a) Show the system sketch (10 pts)(b) the actual power input (10 pts)(c) the exergy destruction (15pts)arrow_forwardHot combustion gases enter the nozzle of a turbojet engine at 250 kPa, 650°C, and 70 m/s and exit at 80 kPa and 420°C. The mass flow rate is 1.2 kg/s. Assume the heat losses to the surroundings is 90kW and the surroundings is at 27°C. Determine (a) the exit velocity and (b) the decrease in the exergy of the gases. Take k = 1.3 and c, = 1.15 kJkg-°C for the combustion gases. Qtoss = 90kW 250 kPa Combustion gases 80 kPa 650°C 420°C 70 m/s m = 1.2 kg/s m = 1.2 kg/sarrow_forwardA geothermal power plant uses geothermal liquid water at 150°C at a rate of 210 kg/s as the heat source, and it produces 5.1 MW of net power in an environment at 25°C. If 7.5 MW of exergy entering the plant with the geothermal water is destroyed within the plant, determine the second-law efficiency.arrow_forward
- Refrigerant-22 absorbs heat from a cooled space at 50°F as it flows through an evaporator of a refrigeration system. R-22 enters the evaporator at 10°F at a rate of 0.08 lbm/s with a quality of 0.3 and leaves as a saturated vapor at the same pressure. Determine the rate of exergy destruction in the evaporato.arrow_forwardAir enters the evaporator section of a window air conditioner at 100 kPa and 27°C with a volume flow rate of 6 m3 /min. Refrigerant-134a at 120 kPa with a quality of 0.3 enters the evaporator at a rate of 2 kg/min and leaves as saturated vapor at the same pressure. Determine the exit temperature of the air and the exergy destruction for this process, assuming the outer surfaces of the air conditioner are insulated.arrow_forward4. Air is compressed steadily in an adiabatic compressor from 100 kPa and 25°c to 500 kPa and 167°C at a rate of 0.025 kg/s. If the power input to this compressor is 8 kW, and assuming the surrounding air to be at 25°C, determine the rate of exergy destroyed in this process, in kW. (Apply cold-air-standard assumptions)arrow_forward
- Steam enters an adiabatic nozzle at 3.5 MPa and 300°C with a low velocity and leaves at 1.6 MPa and 250°C at a rate of 0.4 kg/s. If the ambient state is 100 kPa and 18°C, determine the rate of exergy destruction.arrow_forwardAir enters the evaporator section of a window air conditioner at 100 kPa and 27°C with a volume flow rate of 6 m3 /min. Refrigerant-134a at 120 kPa with a quality of 0.3 enters the evaporator at a rate of 2 kg/min and leaves as saturated vapor at the same pressure. Determine the exit temperature of the air and the exergy destruction for this process, assuming heat is transferred to the evaporator of the air conditioner from the surrounding medium at 32°C at a rate of 30 kJ/min.arrow_forwardA refrigeration unit operates between two heat reservoirs with temperatures of 240 and 320 K. The refrigeration unit itself has a temperature of 230 K during heat addition from the 240 K reservoir and a temperature of 340 K during heat rejection to the 320 K reservoir. The COP of the actual unit is 2.00, and the heat-transfer rate from the 240 K reservoir is 1000 kJ/min. Determine the entropy production rate, in kJ/min · K, for a. the refrigeration unit itself b. the low-temperature heat-transfer process c. the high-temperature heat-transfer process d. Which process has the largest irreversibility?arrow_forward
- A heat engine operated as a reversible Carnot cycle using 1 kg of air as a working fluid between 500 degrees of a high heat source and 27 degrees of a low heat source is operated at 60 cycles per minute. If both the pressure P2 after isothermal expansion and the pressure P4 after isothermal compression are 30Pa, calculate how many kWh of the output power is generated during an hour by this cycle. Air gas constant : 0.287 J/kgK, specific ratio : 1.4 answer : 449.7 kWharrow_forwardA commercial refrigerator is to cool eggplants from 26 to 5 °C at a rate of 380 kg/h. The power input to the refrigerator is 4.5 kW. Determine (a) the rate of cooling, (b) the COP, (c) the exergy of the heat transferred from the low-temperature medium, and (d) the second-law efficiency and the exergy destruction for the cycle. The specific heat of eggplant above freezing is 3.92 kJ/kg.°C.arrow_forwardConsider the compressor of a gas turbine engine which compresses air from 300 K and 100 kPa to 700 kPa and 580 K. Determine the thermal efficiency, in %, if 975 kJ/kg of heat is transferred to the air, assuming a isentropic turbine efficiency of 85%, and constant specific heats at room temperature.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 PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering 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
Thermodynamic Availability, What is?; Author: MechanicaLEi;https://www.youtube.com/watch?v=-04oxjgS99w;License: Standard Youtube License