EBK THERMODYNAMICS: AN ENGINEERING APPR
8th Edition
ISBN: 8220102809444
Author: CENGEL
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 8.8, Problem 113RP
A passive solar house that was losing heat to the outdoors at 5°C at an average rate of 50,000 kJ/h was maintained at 22°C at all times during a winter night for 10 h. The house was heated by 50 glass containers, each containing 20 L of water that was heated to 80°C during the day by absorbing solar energy. A thermostat-controlled 15-kW backup electric resistance heater turned on whenever necessary to keep the house at 22°C. Determine (a) how long the electric heating system was on that night, (b) the exergy destruction, and (c) the minimum work input required for that night, in kJ.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
A room is maintained at 20°C by removing
heat at a rate of 3 kW. The required power
input to the air conditioning unit is 1.5 kW.
Determine the COP.
A passive solar house that was losing heat to the outdoors at 5°C at an average rate of 50,000 kJ/h was maintained at 22°C at all times during a winter night for 10 h. The house was heated by 50 glass containers, each containing 20 L of water that was heated to 80°C during the day by absorbing solar energy. A thermostat-controlled 15-kW backup electric resistance heater turned on whenever necessary to keep the house at 22°C. Determine the minimum work input required for that night, in kJ.
Putting hot foods into the refrigerator without cooling them first not only wastes energy but also could spoil the foods nearby. Is it true?
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
- An air conditioner with refrigerant-134a as the refrigerant is used to keep a large space at 20°C by rejecting the waste heat to the outside air at 37 °C. The room is gaining heat through the walls and the windows at a rate of 125 kJ/min while the heat generated by the computer, TV, and lights amounts to 0.7 kW. Unknown amount of heat is also generated by the people in the room. The condenser and evaporator pressures are 1200 and 500 kPa, respectively. The refrigerant is saturated liguid at the condenser exit and saturated vapor at the compressor inlet. If the refrigerant enters the compressor at a rate of 65 L/min and the isentropic efficiency of the compressor is 70%, determine (a) the temperature of the refrigerant at the compressor exit, (b) the rate of heat generated by the people in the room, (c) the COP of the air conditioner, and (d) the minimum volume flow rate of the refrigerant at the compressor inlet for the same compressor inlet and exit conditions.arrow_forwardA passive solar house that is losing heat to the outdoors at 3C at an average rate of 50,000 kJ/h is maintained at 22C at all times during a winter night for 10 h. The house is to be heated by 50 glass containers, each containing 20 L of water that is heated to 80C during the day by absorbing solar energy. A thermostat-controlled 15 kW backup electric resistance heater turns on whenever necessary to keep the house at 22C. Determine how long the electric heating system was on that night and the amount of entropy generated during the night.arrow_forwardA firm in Manila operates a Diesel Electric Plant to supply its electric energy requirements. During a 2 hour period, the plant consumed 250 gallons of fuel at 80°F and produced 2900 kW-hrs. Industrial fuel is used at 30°API and was purchased at P30/li at 60°F. Determine the overall thermal efficiency of the plant in percent?.arrow_forward
- The maximum efficiency of a heat engine works between 660 K and 323 K isarrow_forwardA heat pump is used to extract heat from the outside atmosphere to heat the inside of a building. On a day when the outside air temperature is Tc°C, the heat pump is operating to a COP of 2.7, maintaining the inside temperature of the building at Th°C. If the building is losing heat at the rate of 62,893 kJ/hour in these conditions, determine how much power (kW) must be supplied to a heat pump.arrow_forwardRequired information Problem 08.048 - DEPENDENT MULTI-PART PROBLEM - ASSIGN ALL PARTS - Piston Device with Refrigerant NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. A piston-cylinder device initially contains 2 kg of refrigerant-134a at 100 kPa and 20°C. Heat is now transferred to the refrigerant from a source at 150°C, and the piston, which is resting on a set of stops, starts moving when the pressure inside reaches 120 kPa. Heat transfer continues until the temperature reaches 80°C. Assume the surroundings to be at 25°C and 100 kPa. R-134a 100 kPa 20°C Q 150°C Problem 08.048.b - Heat Added in a Piston Device with Refrigerant Determine the heat transfer. (You must provide an answer before moving on to the next part.) The heat transfer is kJ.arrow_forward
- please include all stepsarrow_forwardA room measures 4mx7mx5m and the air in it has to be always kept 20 C lower than that of the incoming air. The air inside has to be renewed every 30 minutes. Assuming 75% efficiency, calculate the HP rating of an air-conditioning unit suitable for this purpose. Take specific heat of air as 0.24 and its density as 1.27 kg/m3.arrow_forwardIn a commercial water heater, 80 L/min of water is heated from 20° C to 60° C . Calculate the amount of energy required per hour.arrow_forward
- a) A basement refrigerator is used to store cool beverages during the long hot summer. The refrigerator is maintained at 2°C and the ambient basement temperature is 20°C. Glass bottles filled with cola at 25°C are placed in the refrigerator. Each bottle weighs 0.20 kg and there is 0.25 kg of cola in each bottle. Assume the glass bottles are in thermal equilibrium with the cola at all times (i.e. the temperature of the bottles and cola are equal). The available energy (work) to cool the bottles of cola in the refrigerator space is 110 kJ. The coefficient of performance of the refrigerator is 0.20 % of that of a Carnot refrigerator. Assume the bottle has the properties of plate glass, and the cola has the properties of saturated liquid water. How many bottles containing cola can be placed in the refrigerator and cooled to 2°C? b) Define the reversible (Q /Q.)rev ratio in terms of TH and T. Prove that the coefficient of performance of a reversible heat pump () TH TH-TL" revarrow_forwardA piston-cylinder assembly contains R-134a refrigerant in a volume of 0.15 m3, 0.28 MPa and 40 ° C. Initially the piston is fixed with a pin. The piston-cylinder assembly is heated from a heat source at 150 ° C and the pressure rises to 0.32 MPa. Then the pin is pulled and heat is transferred to an environment at 25 ° C, allowing the R-134a refrigerant to reach 50 ° C at constant pressure. a) Calculate the amount of heat and work transfer in processes. b) Calculate the entropy generation in processes. Comment on the conformity of the processes to the second law of thermodynamics.arrow_forwardAir at 70°F and 1 atm is cooled at the rate of 100,000 to 20°F by refrigeration. ft³ hr If the heat is rejected to the surroundings at a temperature of 70°F, what is the minimum power requirement in hp? Air at 25°C and 1 atm is cooled at the rate of 3000 to -8°C by refrigeration. m³ hr For a surroundings temperature of 25°C, what is the minimum power requirement in kW?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
First Law of Thermodynamics, Basic Introduction - Internal Energy, Heat and Work - Chemistry; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=NyOYW07-L5g;License: Standard youtube license