Thermodynamics: An Engineering Approach
8th Edition
ISBN: 9780073398174
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 4.5, Problem 149FEP
A room contains 75 kg of air at 100 kPa and 15°C. The room has a 250-W refrigerator (the refrigerator consumes 250 W of electricity when running), a 120-W TV, a 1.8-kW electric resistance heater, and a 50-W fan. During a cold winter day, it is observed that the refrigerator, the TV, the fan, and the electric resistance heater are running continuously but the air temperature in the room remains constant. The rate of heat loss from the room that day is
- (a) 5832 kJ/h
- (b) 6192 kJ/h
- (c) 7560 kJ/h
- (d) 7632 kJ/h
- (e) 7992 kJ/h
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A room contains 60 kg of air at 100 kPa and 15°C. The room has a 250-W refrigerator (the refrigerator consumes 250 W of electricity when running), a 120-W TV, a 1-kW electric resistance heater, and a 50-W fan. During a cold winter day, it is observed that the refrigerator, the TV, the fan, and the electric resistance heater are running continuously but the air temperature in the room remains constant. The rate of heat loss from the room that day is
Consider a sealed, rigid container of 10 kg of water vapor at 25°C and 80 kPa. A paddle wheel
with a power rating of 1 kW is operated within the tank for 30 minutes. During that time 7 kJ of
heat are lost to the surroundings.
1.
Define the system.
2.
What types of energy transfer occur?
3.
What is the net energy change of the system?
Taking water as an ideal gas (R = 0.4615 kJ /kg · K and cp = 1.8723 kJ/kg ·
K), determine the final temperature and pressure of the water vapor.
4.
A well-sealed room contains 60 kg of air at 200 kPa and 25°C. Now solar energy enters the room at an average rate of 0.8 kJ/s while a 120-W fan is turned on to circulate the air in the room. If heat transfer through the walls is negligible, the air temperature in the room in 30 min will be (a) 25.6°C (b) 49.8°C (c) 53.4°C (d) 52.5°C (e) 63.4°C
Chapter 4 Solutions
Thermodynamics: An Engineering Approach
Ch. 4.5 - An ideal gas at a given state expands to a fixed...Ch. 4.5 - Nitrogen at an initial state of 300 K, 150 kPa,...Ch. 4.5 - 4–3 The volume of 1 kg of helium in a...Ch. 4.5 - 4–4E Calculate the total work, in Btu, for process...Ch. 4.5 - 4–5 A piston–cylinder device initially contains...Ch. 4.5 - A pistoncylinder device with a set of stops...Ch. 4.5 - 4–7 A piston–cylinder device initially contains...Ch. 4.5 - 4–8 A mass of 5 kg of saturated water vapor at 300...Ch. 4.5 - 1 m3 of saturated liquid water at 200C is expanded...Ch. 4.5 - A gas is compressed from an initial volume of 0.42...
Ch. 4.5 - A mass of 1.5 kg of air at 120 kPa and 24C is...Ch. 4.5 - During some actual expansion and compression...Ch. 4.5 - 4–14 A frictionless piston–cylinder device...Ch. 4.5 - Prob. 15PCh. 4.5 - During an expansion process, the pressure of a gas...Ch. 4.5 - A pistoncylinder device initially contains 0.4 kg...Ch. 4.5 - 4–19E Hydrogen is contained in a piston–cylinder...Ch. 4.5 - A pistoncylinder device contains 0.15 kg of air...Ch. 4.5 - 1 kg of water that is initially at 90C with a...Ch. 4.5 - Prob. 22PCh. 4.5 - An ideal gas undergoes two processes in a...Ch. 4.5 - A pistoncylinder device contains 50 kg of water at...Ch. 4.5 - Prob. 26PCh. 4.5 - 4–27E A closed system undergoes a process in which...Ch. 4.5 - A rigid container equipped with a stirring device...Ch. 4.5 - A 0.5-m3rigid tank contains refrigerant-134a...Ch. 4.5 - A 20-ft3 rigid tank initially contains saturated...Ch. 4.5 - Prob. 31PCh. 4.5 - Prob. 32PCh. 4.5 - Prob. 33PCh. 4.5 - An insulated pistoncylinder device contains 5 L of...Ch. 4.5 -
4–35 A piston–cylinder device initially...Ch. 4.5 - Prob. 37PCh. 4.5 - A 40-L electrical radiator containing heating oil...Ch. 4.5 - Steam at 75 kPa and 8 percent quality is contained...Ch. 4.5 - Prob. 40PCh. 4.5 - An insulated tank is divided into two parts by a...Ch. 4.5 - Is the relation u = mcv,avgT restricted to...Ch. 4.5 - Is the relation h = mcp,avgT restricted to...Ch. 4.5 - Is the energy required to heat air from 295 to 305...Ch. 4.5 - A fixed mass of an ideal gas is heated from 50 to...Ch. 4.5 - A fixed mass of an ideal gas is heated from 50 to...Ch. 4.5 - A fixed mass of an ideal gas is heated from 50 to...Ch. 4.5 - Prob. 49PCh. 4.5 - What is the change in the enthalpy, in kJ/kg, of...Ch. 4.5 - Prob. 51PCh. 4.5 - Prob. 52PCh. 4.5 - Prob. 53PCh. 4.5 - Determine the internal energy change u of...Ch. 4.5 - Prob. 55PCh. 4.5 - Prob. 56PCh. 4.5 - Is it possible to compress an ideal gas...Ch. 4.5 - A 3-m3 rigid tank contains hydrogen at 250 kPa and...Ch. 4.5 - A 10-ft3 tank contains oxygen initially at 14.7...Ch. 4.5 - 4–60E A rigid tank contains 10 Ibm of air at 30...Ch. 4.5 - 4–61E Nitrogen gas to 20 psia and 100°F initially...Ch. 4.5 - An insulated rigid tank is divided into two equal...Ch. 4.5 - 4–63 A 4-m × 5-m × 6-m room is to be heated by a...Ch. 4.5 - 4-64 A student living in a 3-m × 4-m × 4-m...Ch. 4.5 - A 4-m 5-m 7-m room is heated by the radiator of...Ch. 4.5 - 4–66 Argon is compressed in a polytropic process...Ch. 4.5 - An insulated pistoncylinder device contains 100 L...Ch. 4.5 - 4–68 A spring-loaded piston-cylinder device...Ch. 4.5 - An ideal gas contained in a pistoncylinder device...Ch. 4.5 - Air is contained in a variable-load pistoncylinder...Ch. 4.5 - Prob. 71PCh. 4.5 - Prob. 72PCh. 4.5 - Prob. 74PCh. 4.5 - Prob. 75PCh. 4.5 - Prob. 76PCh. 4.5 - 4–77 Air is contained in a piston-cylinder device...Ch. 4.5 - A pistoncylinder device contains 4 kg of argon at...Ch. 4.5 - The state of liquid water is changed from 50 psia...Ch. 4.5 - During a picnic on a hot summer day, all the cold...Ch. 4.5 - Consider a 1000-W iron whose base plate is made of...Ch. 4.5 - Stainless steel ball bearings ( = 8085 kg/m3 and...Ch. 4.5 - In a production facility, 1.6-in-thick 2-ft 2-ft...Ch. 4.5 - Prob. 84PCh. 4.5 - An electronic device dissipating 25 W has a mass...Ch. 4.5 - Prob. 87PCh. 4.5 - 4–88 In a manufacturing facility, 5-cm-diameter...Ch. 4.5 - Prob. 89PCh. 4.5 - Is the metabolizable energy content of a food the...Ch. 4.5 - Is the number of prospective occupants an...Ch. 4.5 - Prob. 92PCh. 4.5 - Prob. 93PCh. 4.5 - Consider two identical 80-kg men who are eating...Ch. 4.5 - A 68-kg woman is planning to bicycle for an hour....Ch. 4.5 - A 90-kg man gives in to temptation and eats an...Ch. 4.5 - A 60-kg man used to have an apple every day after...Ch. 4.5 - Consider a man who has 20 kg of body fat when he...Ch. 4.5 - Consider two identical 50-kg women, Candy and...Ch. 4.5 - Prob. 100PCh. 4.5 - Prob. 101PCh. 4.5 - Prob. 102PCh. 4.5 - Prob. 103PCh. 4.5 - Prob. 104PCh. 4.5 - Prob. 105PCh. 4.5 - Prob. 106PCh. 4.5 - Prob. 107RPCh. 4.5 - Consider a pistoncylinder device that contains 0.5...Ch. 4.5 - Air in the amount of 2 lbm is contained in a...Ch. 4.5 - Air is expanded in a polytropic process with n =...Ch. 4.5 - Nitrogen at 100 kPa and 25C in a rigid vessel is...Ch. 4.5 - Prob. 112RPCh. 4.5 - Prob. 113RPCh. 4.5 - Prob. 114RPCh. 4.5 - 4–115 A mass of 12 kg of saturated...Ch. 4.5 - Prob. 116RPCh. 4.5 - Prob. 117RPCh. 4.5 - Prob. 118RPCh. 4.5 - Prob. 119RPCh. 4.5 - Prob. 120RPCh. 4.5 - Prob. 121RPCh. 4.5 - Prob. 122RPCh. 4.5 - Prob. 123RPCh. 4.5 - Prob. 124RPCh. 4.5 - Prob. 125RPCh. 4.5 - Prob. 126RPCh. 4.5 - Prob. 127RPCh. 4.5 - Prob. 128RPCh. 4.5 - A well-insulated 3-m 4m 6-m room initially at 7C...Ch. 4.5 - Prob. 131RPCh. 4.5 - Prob. 133RPCh. 4.5 - Prob. 134RPCh. 4.5 - An insulated pistoncylinder device initially...Ch. 4.5 - Prob. 137RPCh. 4.5 - Prob. 138RPCh. 4.5 - A pistoncylinder device initially contains 0.35 kg...Ch. 4.5 - Prob. 140RPCh. 4.5 - 4–141 One kilogram of carbon dioxide is compressed...Ch. 4.5 - Prob. 142RPCh. 4.5 - Prob. 143RPCh. 4.5 - Prob. 144FEPCh. 4.5 - A 3-m3 rigid tank contains nitrogen gas at 500 kPa...Ch. 4.5 - Prob. 146FEPCh. 4.5 - A well-sealed room contains 60 kg of air at 200...Ch. 4.5 - Prob. 148FEPCh. 4.5 - A room contains 75 kg of air at 100 kPa and 15C....Ch. 4.5 - A pistoncylinder device contains 5 kg of air at...Ch. 4.5 - Prob. 151FEPCh. 4.5 - Prob. 152FEPCh. 4.5 - A 2-kW electric resistance heater submerged in 5...Ch. 4.5 - 1.5 kg of liquid water initially at 12C is to be...Ch. 4.5 - An ordinary egg with a mass of 0.1 kg and a...Ch. 4.5 - 4–156 An apple with an average mass of 0.18 kg and...Ch. 4.5 - A 6-pack of canned drinks is to be cooled from 18C...Ch. 4.5 - An ideal gas has a gas constant R = 0.3 kJ/kgK and...Ch. 4.5 - Prob. 159FEPCh. 4.5 - Prob. 161FEP
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 50-L electrical radiator containing heating oil is placed in a 50-m³ room. Both the room and the oil in the radiator are initially at 5°C. The radiator with a rating of 3 kW is now turned on. At the same time, heat is lost from the room at an average rate of 0.3 kJ/s. After some time, the average temperature is measured to be 20°C for the air in the room, and 60°C for the oil in the radiator. Taking the density and the specific heat of the oil to be 950 kg/m³ and 2.2kJ/(kg °C), respectively, determine how long the heater is kept on. Assume the room is well-sealed so that there are no air leaks.arrow_forward8. A room contains 60 kg of air at 100 kPa and 15°C. The room has a 250-W refrigerator (the refrigerator consumes 250 W of electricity when running), a 120-W TV, a 1- kW electric resistance heater, and a 50-W fan. During a cold winter day, it is observed that the refrigerator, the TV, the fan, and the electric resistance heater are running continuously but the air temperature in the room remains constant. Solve for the rate of heat loss from the room that day. (3 DECIMAL IN FINAL ANSWER PLS)arrow_forwardA piston-cylinder device contains 4 kg of argon at 250 kPa and 35°C. During a quasi- equilibrium, isothermal expansion process, 15 kJ of boundary work is done by the system, and 3 kJ of paddle-wheel work is done on the system. Determine the heat transfer for this process.arrow_forward
- A 50-L electrical radiator containing heating oil is placed in a well-sealed 75-m3 room. Both the air in the room and the oil in the radiator are initially at the environment temperature of 6°C. Electricity with a rating of 2.4 kW is now turned on. Heat is also lost from the room at an average rate of 0.75 kW. The heater is turned off after some time when the temperatures of the room air and oil are measured to be 20°C and 60°C, respectively. Taking the density and the specific heat of oil to be 950 kg/m3 and 2.2 kJ/kg⋅°C, determine how long the heater is kept on.arrow_forwardA 50-L electrical radiator containing heating oil is placed in a well-sealed 75-m3 room. Both the air in the room and the oil in the radiator are initially at the environment temperature of 6°C. Electricity with a rating of 2.4 kW is now turned on. Heat is also lost from the room at an average rate of 0.75 kW. The heater is turned off after some time when the temperatures of the room air and oil are measured to be 20°C and 60°C, respectively. Taking the density and the specific heat of oil to be 950 kg/m3 and 2.2 kJ/kg⋅°C, determine the exergy destruction.arrow_forwardA 50-L electrical radiator containing heating oil is placed in a well-sealed 75-m3 room. Both the air in the room and the oil in the radiator are initially at the environment temperature of 6°C. Electricity with a rating of 2.4 kW is now turned on. Heat is also lost from the room at an average rate of 0.75 kW. The heater is turned off after some time when the temperatures of the room air and oil are measured to be 20°C and 60°C, respectively. Taking the density and the specific heat of oil to be 950 kg/m3 and 2.2 kJ/kg⋅°C, determine the second-law efficiency for this process.arrow_forward
- A piston–cylinder device containing carbon-dioxide gas undergoes an isobaric process from 15 psia and 80°F to 200°F. Determine the work and the heat transfer associated with this process, in Btu/lbm.arrow_forwardA 1.2 kg of liquid water initially at 15°C is to be heated to 95°C in a teapot equipped with a 1400-W electric heating element inside. The teapot is 0.5 kg and has an average specific heat of 0.7 kJ/kg· °C. Taking the specific heat of water to be 4.18 kJ/kg · °C and disregarding any heat loss from the teapot, determine how long it will take (minutes) for the water to be heated.arrow_forwardA piston-cylinder device contains 0.850 kg of refrigerant-134a at –10.0°C. The piston that is free to move and has a mass of 12.0 kg and a diameter of 25.0 cm. The local atmospheric pressure is 88.0 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 15.0°C. Determine (a) the final pressure, (b) the change in the volume of the cylinder, and (c) the change in the enthalpy of the refrigerant- 134a. Assume the following: va-10°C = 0.2302 m³/kg, va-15°C = 0.2544 m³/kg, ha-10°C = 247.22 kJ/kg, h@15°C = 268.18 kJ/kgarrow_forward
- A rigid tank is divided into two equal parts by a partition. Initially, one side of the tank contains 5 kg of water at 200 kPa and 25°C, and the other side is evacuated. The partition is then removed, and the water expands into the entire tank. The water is allowed to exchange heat with its surroundings until the temperature in the tank returns to the initial value of 25°C. Determine (a) the volume of the tank, (b) the final pressure, and (c) the heat transfer for this processarrow_forwardConsider two identical rooms, one with a 2-kW electric resistance heater and the other with three couples fast dancing. In which room will the air temperature rise more quickly?arrow_forwardNOTE: 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 1 kg saturated liquid water at 200°C. Now heat is transferred to the water until the volume quadruples and the cylinder contains saturated vapor only. The saturated liquid properties of water at 200°C 3 are vf= 0.001157 m³/kg and uf= 850.46 kJ/kg (Table A-4). Water 71 kg 200°C Q Determine the internal energy change of the water. The change in internal energy is kJ.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
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