Heat and Mass Transfer: Fundamentals and Applications
5th Edition
ISBN: 9780073398181
Author: Yunus A. Cengel Dr., Afshin J. Ghajar
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 3, Problem 69P
A 12-m-long and 5-m-high wall is constructed of two layers of 1 -cm-thick sheetrock
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A 4-m-high and 6-m-wide wall consists of a long 18-cm x 30-cm cross section of horizontal bricks (k = 0.72 W/mK) separated by 3-cm-thick plaster layers (k=0.22 W/mK). There are also 2-cm-thick plaster layers on each side of the wall, and a 2-cm-thick rigid foam (k=0.026 W/mK) on the inner side of the wall. The indoor and outdoor temperatures are 22°C and -4°C, and the convection heat transfer coefficients on the inner and the outer sides are h1= 10 W/m2K and h2= 20 W/m2K, respectively.Assuming one-dimensional heat transfer and disregarding radiation, determine the rate of heat transfer through the wall.
A spherical tank with internal diameter of 2 m made of 2.0-cm-thick stainless steel
(k=15 W/m.K) is used for storing a fluid at a temperature of 1 °C. The tank is covered
with a 4-cm-thick layer of an insulation (k=0.25 W/m.K). The surrounding air is at 15
°C. The inside and outside heat transfer coefficients are 35 and 10 W/m2.K,
respectively.
Required: Draw the thermal resistance network (thermal circuit) and label the associated
resistance and determine the following:
The individual thermal resistance associated with the thermal circuit.
a)
b)
c)
d)
The total thermal resistance value
The rate of heat transfer
The temperature difference across the tank shell and the insulation layer.
A 10 cm thick wall is to be constructed with 2.5 m long wood studs (k = 0.11 W/m.K), that has a cross section of 10 cm × 10 cm. At some point the builder has run out of those stud and started using pairs of 2.5 m long wood stud with cross section of 5 cm × 10 cm nailed to each other instead. The manganese steel nails (k = 50 W/m.K) are 10 cm long and have dia of 0.4 cm. A total 50 nails are used to connect the two studs. The temperature difference between inner and outer wall is 15°C. Assuming negligible thermal contact resistance between two layers. Calculate heat transfer rate (i) through a solid stud, (ii) through stud pair with equal length and width nailed to each other, (iii) also, determine the effective thermal conductivity of the nailed stud pair.
Chapter 3 Solutions
Heat and Mass Transfer: Fundamentals and Applications
Ch. 3 - Consider heat conduction through a wall of...Ch. 3 - Consider heat conduction through a plane wall....Ch. 3 - What does the thermal resistance of a medium...Ch. 3 - Can we defme the convection resistance for a unit...Ch. 3 - Consider steady heat transfer through the wall of...Ch. 3 - How is the combined heat transfer coefficient...Ch. 3 - Why are the convection and the radiation...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Someone comments that a microwave oven can be...Ch. 3 - Consider two cold canned drinks, one wrapped in a...
Ch. 3 - The bottom of a pan is made of a 4-mm-thick...Ch. 3 - Consider a surface of area A at which the...Ch. 3 - How does the thermal resistance network associated...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Consider a window glass consisting of two...Ch. 3 - Prob. 16PCh. 3 - Consider a person standing in a room at 20C with...Ch. 3 - Consider an electrically heated brick house...Ch. 3 - A12-cm18-cm circuit board houses on its surface...Ch. 3 - Water is boiling in a 25-cm-diameter aluminum pan...Ch. 3 - A cylindrical resistor element on a circuit board...Ch. 3 - Prob. 22PCh. 3 - A1.0m1.5m double-pane window consists of two...Ch. 3 - Prob. 24PCh. 3 - Prob. 25PCh. 3 - Prob. 26PCh. 3 - Prob. 27PCh. 3 - Prob. 28EPCh. 3 - To defog the rear window of an automobile, a very...Ch. 3 - A transparent film is to be bonded onto the top...Ch. 3 - To defrost ice accumulated on the outer surface of...Ch. 3 - Prob. 32PCh. 3 - Prob. 33PCh. 3 - Prob. 34PCh. 3 - Prob. 35PCh. 3 - Prob. 36PCh. 3 - Heat is to be conducted along a circuit board that...Ch. 3 - Prob. 38EPCh. 3 - Consider a house that has a 10m20-m base and a...Ch. 3 - Prob. 40EPCh. 3 - Prob. 41PCh. 3 - Prob. 42PCh. 3 - What is thermal contact resistance? How is it...Ch. 3 - Will the thermal contact resistance be greater for...Ch. 3 - Explain how the thermal contact resistance can be...Ch. 3 - A waII consists of two layers of insulation...Ch. 3 - Prob. 47CPCh. 3 - Consider two surfaces pressed against each other....Ch. 3 - Prob. 49PCh. 3 - Two 5-cm-diameter, 15-cm-long aluminum bars...Ch. 3 - Prob. 51PCh. 3 - Two identical aluminum plates with thickness of 30...Ch. 3 - A tvolayer wall is made of two metal plates, with...Ch. 3 - An aluminum plate and a stainless steel plate are...Ch. 3 - Prob. 55PCh. 3 - Prob. 56PCh. 3 - Prob. 57PCh. 3 - What are the two approaches used in the...Ch. 3 - The thermal resistance networks can also be used...Ch. 3 - When plotting the thermal resistance network...Ch. 3 - A 10-cm-thick vall is to be constructed with...Ch. 3 - Prob. 62EPCh. 3 - Prob. 63PCh. 3 - Prob. 64PCh. 3 - Prob. 65PCh. 3 - Prob. 66PCh. 3 - Prob. 67PCh. 3 - Prob. 68PCh. 3 - A 12-m-long and 5-m-high wall is constructed of...Ch. 3 - Prob. 70EPCh. 3 - Prob. 71PCh. 3 - Prob. 72PCh. 3 - What is an infinitely long cylinder? When is it...Ch. 3 - Can the thermal resistance concept be used for a...Ch. 3 - Consider a short cylinder whose top and bottom...Ch. 3 - Prob. 76PCh. 3 - Prob. 77PCh. 3 - Prob. 78PCh. 3 - Superheated steam at an average temperature 20C is...Ch. 3 - Prob. 80EPCh. 3 - Prob. 81EPCh. 3 - Prob. 82PCh. 3 - Prob. 83PCh. 3 - Prob. 84PCh. 3 - Prob. 85PCh. 3 - Prob. 86EPCh. 3 - Prob. 87PCh. 3 - Prob. 88PCh. 3 - Liquid hydrogen is flowing through an insulated...Ch. 3 - Exposure to high concentrations of gaseous ammonia...Ch. 3 - A mixture of chemicals is flowing in a pipe...Ch. 3 - Ice slurry is being transported in a pipe...Ch. 3 - Prob. 93PCh. 3 - Prob. 94PCh. 3 - Prob. 95PCh. 3 - What is the critical radius of insulation? How is...Ch. 3 - Prob. 97CPCh. 3 - Prob. 98CPCh. 3 - Prob. 99CPCh. 3 - A pipe is insulated such that the outer radius of...Ch. 3 - A 0.083-in-diameter electrical wire at 90F is...Ch. 3 - Repeat Prob. 3-109E, assuming a thermal contact...Ch. 3 - Prob. 103PCh. 3 - Prob. 104PCh. 3 - Hot air is to be cooled as it is forced to flow...Ch. 3 - Prob. 106CPCh. 3 - Prob. 107CPCh. 3 - The fins attached to a surface are determined to...Ch. 3 - Explain how the fins enhance heat transfer from a...Ch. 3 - How does the overall effectiveness of a finned...Ch. 3 - Hot water is to be cooled as it flows through the...Ch. 3 - Consider two finned surfaces that are identical...Ch. 3 - The heat transfer surface area of a fin is equal...Ch. 3 - Does the (a) efficiency and (b) effectiveness of a...Ch. 3 - Two pin fins are identical, except that the...Ch. 3 - Two plate fins of constant rectangular cross...Ch. 3 - Two finned surfaces are identical, except that the...Ch. 3 - Obtain a relation for the fin efficiency for a fin...Ch. 3 - Prob. 119PCh. 3 - Consider a very long rectangular fin attached to a...Ch. 3 - Prob. 121PCh. 3 - Prob. 122EPCh. 3 - Prob. 123EPCh. 3 - Prob. 124PCh. 3 - Prob. 125PCh. 3 - Prob. 126PCh. 3 - Prob. 127PCh. 3 - Prob. 128PCh. 3 - Prob. 129PCh. 3 - Prob. 130PCh. 3 - Prob. 131PCh. 3 - Prob. 132PCh. 3 - Prob. 133PCh. 3 - Prob. 134PCh. 3 - The human body is adaptable to extreme climatic...Ch. 3 - Consider the conditions of Example 3-14 in the...Ch. 3 - Consider the conditions of Example 3-14 in the...Ch. 3 - Prob. 138PCh. 3 - What is a conduction shape factor? How is it...Ch. 3 - What is the value of conduction shape factors in...Ch. 3 - Prob. 141PCh. 3 - A thin-walled cylindrical container is placed...Ch. 3 - Prob. 143PCh. 3 - Prob. 144PCh. 3 - Prob. 145PCh. 3 - Prob. 146EPCh. 3 - Prob. 147PCh. 3 - Prob. 148PCh. 3 - Prob. 149PCh. 3 - Prob. 150PCh. 3 - Prob. 151PCh. 3 - Prob. 152PCh. 3 - Consider a house with a flat roof whose outer...Ch. 3 - Prob. 154PCh. 3 - Radioactive material, stored in a spherical vessel...Ch. 3 - What is the R-value of a wall? How does it differ...Ch. 3 - What is effective emissivity for a plane-parallel...Ch. 3 - Prob. 158CPCh. 3 - What is a radiant barrier? What kinds of materials...Ch. 3 - Consider a house whose attic space is ventilated...Ch. 3 - Prob. 161PCh. 3 - Prob. 162PCh. 3 - Prob. 163PCh. 3 - Prob. 164PCh. 3 - Prob. 165PCh. 3 - Prob. 166PCh. 3 - Determine the winter R-value and the U-factor of a...Ch. 3 - The overall heat transfer coefficient (the...Ch. 3 - Prob. 169EPCh. 3 - Determine the summer and winter R-values. in m2 ....Ch. 3 - The overall heat transfer coefficient of a wall is...Ch. 3 - Two homes are identical, except that the walls of...Ch. 3 - Prob. 173PCh. 3 - Consider two identical people each generating 60 V...Ch. 3 - Cold conditioned air at 12C is flowing inside a...Ch. 3 - Hot water is flowing at an average velocity of 1.5...Ch. 3 - Prob. 177PCh. 3 - Prob. 178PCh. 3 - Prob. 179PCh. 3 - Prob. 180PCh. 3 - Prob. 181PCh. 3 - Prob. 182PCh. 3 - Prob. 183PCh. 3 - Prob. 184PCh. 3 - Prob. 185PCh. 3 - A total of 10 rectangular aluminum fins...Ch. 3 - Prob. 187PCh. 3 - A plane wall surface at 200C is to be cooled with...Ch. 3 - Prob. 189PCh. 3 - Prob. 190PCh. 3 - Prob. 191PCh. 3 - Prob. 192PCh. 3 - A 0.6-rn-diameter, 1.9-rn-long cylindrical tank...Ch. 3 - Prob. 194PCh. 3 - Prob. 195PCh. 3 - A thin-walled spherical tank is buried in the...Ch. 3 - Heat is lost at a rate of 275 W per m2 area of a 1...Ch. 3 - Prob. 198PCh. 3 - Heat is generated steadily in a 3-cm-diameter...Ch. 3 - Prob. 200PCh. 3 - Prob. 201PCh. 3 - Prob. 202PCh. 3 - Prob. 203PCh. 3 - Prob. 204PCh. 3 - Consider two walls. A and B, with the same surface...Ch. 3 - Prob. 206PCh. 3 - A room at 20C air temperature is losing heat to...Ch. 3 - Prob. 208PCh. 3 - A 1-cm-diameter, 30cm-long fin made of aluminum...Ch. 3 - A hot surface at 80C in air at 20C is to be cooled...Ch. 3 - A cylindrical pin fin of diameter 0.6 cm and...Ch. 3 - A 3-cm-long. 2-nuti x 2-mm rectangular...Ch. 3 - Two finned surfaces with long fins are identical,...Ch. 3 - A 20-cm-diameter hot sphere at 120C is buried in...Ch. 3 - A 25-cm-diameter, 2.4-rn-long vertical cylinder...Ch. 3 - Prob. 216PCh. 3 - The walls of a food storage facility are made of a...Ch. 3 - The equivalent thermal resistance for the thermal...Ch. 3 - Prob. 219PCh. 3 - Prob. 220PCh. 3 - Prob. 221PCh. 3 - The fin efficiency is defined as the ratio of the...Ch. 3 - Prob. 223PCh. 3 - In the United States, building insulation is...Ch. 3 - Prob. 225PCh. 3 - A plane brick wall (k=0.7W/m.K) and is 10 cm...Ch. 3 - The temperature in deep space is close to absolute...Ch. 3 - In the design of electronic components, it is...Ch. 3 - Using cylindrical samples of the same material,...Ch. 3 - Find out about the wall construction of the cabins...Ch. 3 - Prob. 231PCh. 3 - A house with 200-m2 floor space is to be heated...
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 4-m-high and 6-m-wide wall consists of a long 15-cm × 25-cm cross section of horizontal bricks (k= 0.72 W/m K) separated by 3-cm- thick plaster layers (k= 0.22 W/m·K). There are also 2-cm-thick plaster layers on each side of the wall and a 2-cm-thick rigid foam (k= 0.026 W/m-K) on the inner side of the wall. The indoor and the outdoor temperatures are 23°C and -4°C, and the convection heat transfer coefficients on the inner and the outer sides are hy = 10 W/m2 .K and hz = 20 W/m2 .K, respectively. Assuming one- dimensional heat transfer and disregarding radiation, determine the rate of heat transfer through the wall. Foam -Plaster $1.5 cm Brick 25 cm $1.5 cm le15 cm - The rate of heat transfer through the wall is W.arrow_forwardA 12-m-long and 5-m-high wall is constructed of two layers of 1-cm-thick sheetrock (k = 0.17 W/m·K) spaced 16 cm by wood studs (k = 0.11 W/m·K) whose cross section is 16 cm * 5 cm. The studs are placed vertically 60 cm apart, and the space between them is filled with fiberglass insulation (k = 0.034 W/m·K). The house is maintained at 20°C and the ambient temperature outside is 29°C. Taking the heat transfer coefficients at the inner and outer surfaces of the house to be 8.3 and 34 W/m2·K, respectively, determine (a) the thermal resistance of the wall considering a representative section of it and (b) the rate of heat transfer through the wall.arrow_forwardA cylindrical cold storage facility with an inner diameter of 4m and height of 2m is constructed. For the wall, the first layer is 6 cm of glass wool (0.1 W/m-C), followed by 30 cm of concrete. The temperature inside is maintained at -10C (hin = 55 W/m^2-C) while the outside temperature is 10°C (hout = 22 w/m^2-C). If the steady rate of heat transfer is at 60W, (a) what is the thermal conductivity of concrete? (b) At what radius is the temperature at 0°C? To prevent water condensation inside the concrete wall (which damages the structure), A 5 cm layer of insulation (k = 0.15 W/m-C) is added to the exterior of the facility. (c) What is the new rate of heat transfer?arrow_forward
- A cylindrical cold storage facility with an inner diameter of 4m and height of 2m is constructed. For the wall, the first layer is 6 cm of glass wool (0.1 W/m-C), followed by 30 cm of concrete. The temperature inside is maintained at -10C (hin = 55 W/m^2-C) while the outside temperature is 10°C (hout = 22 w/m^2-C). If the steady rate of heat transfer is at 60W, (a) what is the thermal conductivity of concrete? (b) At what radius is the temperature at 0°C? To prevent water condensation inside the concrete wall (which damages the structure), A 5 cm layer of insulation (k = 0.15 W/m-C) is added to the exterior of the facility. (c) What is the new rate of heat transfer? (d) What is the temperature at the interface of the concrete wall and new insulation? (e) is condensation within the core of the wall prevented?arrow_forwardInsert Space 61 Exercise 6 A 3-194 A 4-m-high and 6-m-long wall is constructed of two large 0.8-cm-thick steel plates (k= 15 W/m-K) separated by 1-cm-thick and 22-cm-wide steel bars placed 99 cm apart. The remaining space between the steel plates is filled with fiberglass insulation (k=0.035 W/m-K). If the temperature difference between the inner and the outer surfaces of the walls is 22°C. determine the rate of heat transfer through the wall. Can we ignore the steel bars between the plates in heat transfer analysis since they occupy only 1 percent of the heat transfer surface area? Steel plates 0.8 cm 22 cm Fiberglass insulation 99 cm 1 cm 0.8 cm Pencil + >arrow_forwardA 10-in-thick, 26-ft-long, and 10-ft-high wall is to be constructed using 9-in-long solid bricks (k = 0.40 Btu/h⋅ft⋅°F) of cross section 7 in × 7 in, or identical-size bricks with nine square air holes (k = 0.015 Btu/h⋅ft⋅°F) that are 9 in long and have a cross section of 1.5 in × 1.5 in. There is a 0.5-in-thick plaster layer (k = 0.10 Btu/h⋅ft⋅°F) between two adjacent bricks on all four sides and on both sides of the wall. The house is maintained at 80°F and the ambient temperature outside is 35°F. Take the heat transfer coefficients at the inner and outer surfaces of the wall to be 1.5 and 6 Btu/h⋅ft2⋅°F, respectively.arrow_forward
- A 10-in-thick, 26-ft-long, and 10-ft-high wall is to be constructed using 9-in-long solid bricks (k = 0.40 Btu/h⋅ft⋅°F) of cross section 7 in × 7 in, or identical-size bricks with nine square air holes (k = 0.015 Btu/h⋅ft⋅°F) that are 9 in long and have a cross section of 1.5 in × 1.5 in. There is a 0.5-in-thick plaster layer (k = 0.10 Btu/h⋅ft⋅°F) between two adjacent bricks on all four sides and on both sides of the wall. The house is maintained at 80°F and the ambient temperature outside is 35°F. Take the heat transfer coefficients at the inner and outer surfaces of the wall to be 1.5 and 6 Btu/h⋅ft2⋅°F, respectively. Determine the rate of heat transfer through the wall constructed of solid bricks.arrow_forwardRadioactive material is stored in a spherical vessel with a diameter of 3.7 m, and the center of the vessel is 11 m below the ground. The vessel is surrounded by a 10.2 cm thick layer of rigid foam insulation (k = 0.026 W/m-K). The radioactive material releases heat at a rate of 1000 W/m³. The surface of the soil it's buried in (k = 2 W/m- K) is exposed to wind with a temperature of 20°C and a convection coefficient of 17 W/m²-K. What is the temperature of the surface of the tank?arrow_forwardThere are 3 windows in a room with a width of 100 cm and a height of 150 cm.There is a single glass (k=0. 9 W/mK) of 5 mm thickness in the windows initially. Instead of these glasses to save heatYou are considering replacing it with double glazing consisting of 5 mm glass and 12 mm air (k=0.022 W/mK). Indoor and outdoor environmenttemperatures are 20 0C and -10 0C, respectively, and the heat transfer coefficients are 7 W/m2 K and 25 W/m2 K. The total heat loss in the room is 3.5 kW.when switching to double glazing;a) Find the decrease in heat transfer. b) Considering that the heat given by the heaters remains 3.5 kW, what would the room temperature be?arrow_forward
- A hot steam pipe having an inside surface temperature of 250°C has an inside diameter of 8 cm and a wall thickness of 5.5 mm. It is covered with a 9-cm layer of insulation having k =0.5 W/m-°C, followed by a 4-cm layer of insulation having k =0.25W/m-°C. The outside temperature of the insulation is 20°C. Calculate the heat lost per meter of length. Assume k =47 W/m-°C for the pipe.arrow_forwardA 12 m long and 5 m high wall is constructed of two layers of 1 cm thick sheetrock (& = 0.17 W/m. °C) spaced 16 cm by wood studs & = 0.11 W/m °C) whose cross section is 16 cm x 5 cm. The studs are placed vertically 60 cm apart, and the space between them is filled with fiberglass insulation (* = 0.034 W/m. °C). The house is maintained at 20°C and the ambient temperature outside is -9°C. Taking the heat transfer coefficients at the inner and outer surfaces of the house to be 8.3 and 34 W/m?. °C respectively, determine (a) The thermal resistance of the wall considering a representative section of it (b) The rate of heat transfer through the wallarrow_forwardA 4-m-high and 6-m-wide wall consists of a long18-cm * 30-cm cross section of horizontal bricks (k =0.72 W/m·K) separated by 3-cm-thick plaster layers (k =0.22 W/m·K). There are also 2-cm-thick plaster layers on eachside of the wall, and a 2-cm-thick rigid foam (k = 0.026 W/m·K)on the inner side of the wall. The indoor and the outdoor temperaturesare 22°C and 24°C, and the convection heat transfercoefficients on the inner and the outer sides are h1 = 10 W/m2·Kand h2 = 20 W/m2·K, respectively. Assuming one-dimensionalheat transfer and disregarding radiation, determine the rate ofheat transfer through the wall.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
Understanding Conduction and the Heat Equation; Author: The Efficient Engineer;https://www.youtube.com/watch?v=6jQsLAqrZGQ;License: Standard youtube license