Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470501979
Author: Frank P. Incropera, David P. DeWitt, Theodore L. Bergman, Adrienne S. Lavine
Publisher: Wiley, John & Sons, Incorporated
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 13, Problem 13.48P
Consider the attic of a home located in a hot climate. The floor of the attic is characterized by a width of
(a) Consider installation on (lie bottom of the attic roof only. Determine the ratio of (lie radiation heat transfer after to before the installation of the foil.
(b) Determine the ratio of the radiation heat transfer after to before installation if the foil is installed only on the top of the attic floor.
(c) Determine the ratio of the radiation heat transfer if the foil is installed on both the roof bottom and the floor top.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
An electronic box that consumes 200 W of power is cooled by a fan blowing air into the box enclosure. The dimensions of the electronic box are 15 cm * 50 cm * 50 cm, and all surfaces of the box are exposed to the ambient except the base surface. Temperature measurements indicate that the box is at an average temperature of 32°C when the ambient temperature and the temperature of the surrounding walls are 25°C. If the emissivity of the outer surface of the box is 0.75, determine the fraction of the heat lost from the outer surfaces of the electronic box.
In a new residential project, you strongly believe that double-paned windows are ‘better’ than single-paned windows. Compare the rate of heat loss between single and double-paned windows(1.5 m x 1 m) if the thickness of each pane is (th = 0.4 cm) and (k = 0.9 W/m.K). The indoor and outdoor temperatures are 18 °C and 2 °C, respectively. Thickness of the air gap between the double-paned windows is (th = 1 cm), and (k = 0.022 W/m.K). Image credit: Windowwhirl.
In a new residential project, you strongly believe that double-paned windows are ‘better’ than single-paned windows. Compare the rate of heat loss between single and double-paned windows (1.5 m x 1 m) if the thickness of each pane is (th = 0.4 cm) and (k = 0.9 W/m.K). The indoor and outdoor temperatures are 18 °C and 2 °C, respectively. Thickness of the air gap between the double-paned windows is (th = 1 cm), and (k = 0.022 W/m.K).
Chapter 13 Solutions
Fundamentals of Heat and Mass Transfer
Ch. 13 - Determine F12 and F21 for the following...Ch. 13 - Drive expressions for the view factor F12...Ch. 13 - A right-circular cone and a right-circular...Ch. 13 - Consider the two parallel, coaxial, ringshaped...Ch. 13 - The “crossed-strings” method of Hottel [13]...Ch. 13 - Consider the rightcircular cylinder of diameter D,...Ch. 13 - Consider the parallel rectangles shown...Ch. 13 - Consider the perpendicular rectangles shown...Ch. 13 - The reciprocity relation, the summation rule, and...Ch. 13 - Determine the shape factor, F12, for the...
Ch. 13 - Consider parallel planes of infinite extent normal...Ch. 13 - Consider the parallel planes of infinite extent...Ch. 13 - Consider two diffuse surfaces A1 and A2 on the...Ch. 13 - As shown in the sketch, consider the disk A1...Ch. 13 - A heat flux gage of 4mm diameter is positioned...Ch. 13 - A circular ice rink 25 m in diameter is enclosed...Ch. 13 - A drying oven consists of a long semicircular duct...Ch. 13 - Consider the arrangement of the three black...Ch. 13 - A long, Vshaped pan is heat treated by suspending...Ch. 13 - Consider coaxial, parallel, black disks separated...Ch. 13 - A tubular healer with a black inner surface of...Ch. 13 - A circular plate of 500-mm diameter is maintained...Ch. 13 - To enhance heat rejection from a spacecraft, an...Ch. 13 - Determine the temperatures of surfaces 1 through 4...Ch. 13 - A cylindrical cavity of diameter D and depth L is...Ch. 13 - In the arrangement shown, the tower disk has a...Ch. 13 - Two plane coaxial disks are separated by a...Ch. 13 - A radiometer views a small target (1) that is...Ch. 13 - A meter to measure the power of a laser beam is...Ch. 13 - The arrangement shown is to be used to calibrate a...Ch. 13 - A long, cylindrical heating element of 20-mm...Ch. 13 - Water flowing through a large number of long,...Ch. 13 - A row of regularly spaced, cylindrical heating...Ch. 13 - A manufacturing process calls for heating long...Ch. 13 - Consider the very long, inclined black surfaces...Ch. 13 - Many products are processed in a manner that...Ch. 13 - Consider two very large parallel plates with...Ch. 13 - A flat-bottomed hole 6 mm in diameter is bored to...Ch. 13 - In Problems 12.20 and 12.25, we estimated the...Ch. 13 - Consider the cavities formed by a cone, cylinder,...Ch. 13 - Consider the attic of a home located in a hot...Ch. 13 - A long, thin-walled horizontal tube 100 mm in...Ch. 13 - A t=5-mm -thick sheet of anodized aluminum is used...Ch. 13 - Consider the spacecraft heat rejection scheme of...Ch. 13 - A very long electrical conductor 10 mm in diameter...Ch. 13 - Liquid oxygen is stored in a thin-walled,...Ch. 13 - Two concentric spheres of diameter D1=0.8m and...Ch. 13 - Determine the steady-stale temperatures of two...Ch. 13 - Consider two large (infinite) parallel planes that...Ch. 13 - Consider two large, diffuse, gray, parallel...Ch. 13 - Heat transfer by radiation occurs between two...Ch. 13 - The end of a cylindrical liquid cryogenic...Ch. 13 - At the bottom of a very large vacuum chamber whose...Ch. 13 - A furnace is located next to a dense array of...Ch. 13 - A cryogenic fluid flows through a tube 20 mm in...Ch. 13 - A diffuse, gray radiation shield of 60mm diameter...Ch. 13 - Consider the three-surface enclosure shown. The...Ch. 13 - Two parallel, aligned disks, 0.4 m in diameter and...Ch. 13 - Coatings applied to long metallic strips are cured...Ch. 13 - A molten aluminum alloy at 900 K is poured into a...Ch. 13 - A long, hemicylindrical (1-m radius) shaped...Ch. 13 - The bottom of a steam-producing still of 200-mm...Ch. 13 - A long cylindrical healer element of diameter...Ch. 13 - A radiative heater consists of a bank of ceramic...Ch. 13 - Consider a long duct constructed with diffuse,...Ch. 13 - A solar collector consists of a long duct through...Ch. 13 - The cylindrical peephole in a furnace wall of...Ch. 13 - A composite wall is comprised of two large plates...Ch. 13 - A small disk of diameter D1=50mm and emissivity...Ch. 13 - Consider a cylindrical cavity of diameter D=100mm...Ch. 13 - Consider a circular furnace that is 0.3 m long and...Ch. 13 - Consider two very large metal parallel plates. The...Ch. 13 - Two convex objects are inside a large vacuum...Ch. 13 - the diffuse, gray, four-surface enclosure with all...Ch. 13 - A cylindrical furnace for heal-treating materials...Ch. 13 - A laboratory oven bas a cubical interior chamber 1...Ch. 13 - A small oven consists of a cubical box of...Ch. 13 - An opaque, diffuse, gray (200mm200mm) plate with...Ch. 13 - A tool for processing silicon waters is housed...Ch. 13 - Consider Problem 6.17. The stationary plate,...Ch. 13 - Most architects know that the ailing of an...Ch. 13 - Boiler tubes exposed to the products of coal...Ch. 13 - Consider two very large parallel plates. The...Ch. 13 - Coated metallic disks are cured by placing them at...Ch. 13 - A double-glazed window consists of two panes of...Ch. 13 - Electrical conductors, in the form of parallel...Ch. 13 - The spectral absorptivity of a large diffuse...Ch. 13 - The cross section of a long circular tube, which...Ch. 13 - Cylindrical pillars similar to those of Problem...Ch. 13 - A row of regularly spaced, cylindrical healing...Ch. 13 - The composite insulation shown, which was...Ch. 13 - Hot coffee is contained in a cylindrical thermos...Ch. 13 - Consider a vertical, double-pane window for the...Ch. 13 - Consider the double-pane window of Problem 9.95,...Ch. 13 - A flat-plate solar collector, consisting of an...Ch. 13 - Consider the tube and radiation shield of Problem...Ch. 13 - Consider the tube and radiation shield of Problem...Ch. 13 - Consider the flatplate solar collector of Problem...Ch. 13 - The lower side of a 400-mm-diameter disk is heated...Ch. 13 - The surface of a radiation shield facing a black...Ch. 13 - The fire tube of a hot water heater consists of a...Ch. 13 - Consider the conditions of Problem 9.107....Ch. 13 - A special surface coating on a square panel that...Ch. 13 - A long rod heater of diameter D1=10mm and...Ch. 13 - A radiant heater, which is used for surface...Ch. 13 - A steam generator consists of an in-line array of...Ch. 13 - A furnace having a spherical cavity of 0.5-m...Ch. 13 - A gas turbine combustion chamber may be...Ch. 13 - A flue gas at 1-atm total pressure and a...Ch. 13 - A furnace consists of two large parallel plates...Ch. 13 - In an industrial process, products of combustion...Ch. 13 - A grain dryer consists of a long semicircular duct...Ch. 13 - A novel infrared recycler has been proposed for...
Additional Engineering Textbook Solutions
Find more solutions based on key concepts
The spring of k and unstretched length 1.5R is attached to the disk at a radial distance of 0.75R from the cent...
Engineering Mechanics: Statics
What parts are included in the vehicle chassis?
Automotive Technology: Principles, Diagnosis, And Service (6th Edition) (halderman Automotive Series)
What types of polymers are most commonly blow molded?
DeGarmo's Materials and Processes in Manufacturing
19.8 Calculate the allowable tensile load for the connection shown. The plates are ASTM A36 steel and the weld ...
Applied Statics and Strength of Materials (6th Edition)
List several uses of the arbor press.
Machine Tool Practices (10th Edition)
Locate the centroid of the area. Prob. 9-17
Engineering Mechanics: Statics
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 horizontal, 3-mm-thick flat-copper plate, 1-m long and 0.5-m wide, is exposed in air at 27C to radiation from the sun. If the total rate of solar radiation absorbed is 300 W and the combined radiation and convection heat transfer coefficients on the upper and lower surfaces are 20 and 15W/m2K, respectively, determine the equilibrium temperature of the plate.arrow_forward1.11 Calculate the heat loss through a glass window 7-mm thick if the inner surface temperature is 20°C and the outer surface temperature is 17°C. Comment on the possible effect of radiation on your answer.arrow_forwardTwo very large walls are at constant temperature of 658oF and 856oF. Assuming that the walls behave like black bodies, how much heat in Btu/hr-ft2 must be removed from the colder wall in order to maintain a constant pressure (σ=0.1714x10-8 Btu/hr-ft2-R)arrow_forward
- Consider a thin 16-cm-long and 20-cm-wide horizontal plate suspended in air at 20°C. The plate is equipped with electric resistance heating elements with a rating of 20 W. Now the heater is turned on and the plate temperature rises. Determine the temperature of the plate when steady operating conditions are reached. The plate has an emissivity of 0.90 and the surrounding surfaces are at 17°C. As an initial guess, assume a surface temperature of 50°C. Is this a good assumption?arrow_forwardA hot liquid is filled in a spherical tank with an inner diameter of 3 m and a wall thickness of 3 cm. The tank wall is made of a material with a thermal conductivity of 0.15 W/m∙K.The hot liquid in the tank causes the inner surface temperature to be 100°C, while the tank outer surface is exposed to air at 20°C and has an emissivity of 0.35. Determine the outer surface temperature of the tank. Assume that the properties of air can be evaluated at 40°C and 1 atm pressure. Is this a good assumption?arrow_forwardThe temperature of a tank in the form of liquid nitrogen is -10 ° C. Tank diameter is 16 cm. The amount of heat lost by convection and radiation from the tank to the environment is 65.5 W / m. Calculate the temperature of the environment where the tank is located .h = 4.35 W / m2K, e= 1.arrow_forward
- An average person generates heat at a rate of 240 Btu/h while resting in a room at 70°F. Assuming onequarter of this heat is lost from the head and taking the emissivity of the skin to be 0.9, determine the average surface temperature of the head when it is not covered. The head can be approximated as a 12-in-diameter sphere, and the interior surfaces of the room can be assumed to be at the room temperature.arrow_forward1. (a) Consider a room with a 1.8-m-high and 2.0-m-wide double-pane window consisting of two 4-mm-thick layers of glass separated by a 10-mm-wide stagnant air space. The convection heat transfer coefficients on the inner and outer surfaces of the window are 12 W/m2 K and 25 W/m2 K, respectively, while the average thermal conductivity of glass is 0.78 W/m K; and the air, 0.026 W/m K. If the room is maintained at 22 oC, the outside temperature is -4 oC and heat transfer due to radiation can be neglected, determine: (i) Draw the sketch and thermal resistance network; (ii) the total thermal resistance; (iii) the steady rate of heat transfer through this double-pane window; (iv) the temperature of the inner surface of the window.…arrow_forwardBecause you forgot to let the pipes drip during a freezing night, a section of an outdoor pipe is now frozen. The frozen section is L = 1 m long and the inner pipe diameter is D = 1.8 cm. During the day, the pipe is exposed to the cold air, the Sun, and the radiating surroundings. The cold air temperature is T∞ = -10°C, and has convection heat transfer coefficient h = 20 W/m2·K. The Sun provides solar irradiance of Gsun = 1350 W/m2. The steel pipe surface has absorptivity α = 0.6 and emissivity ε= 0.1. The surroundings, such as vegetation, houses, ground, etc. can be assumed to be blackbody held at Tsur = 280 K. A) Using the energy conservation system illustrated below, establish an equation that describes the stored energy in the section of frozen water (Est). B) Determine the amount of time needed to melt the ice in the pipe. Ice has density ρ= 920 kg/m3, and latent heat of fusion hsf = 334 kJ/kg. The ice is Tw = 0°C. Ignore conduction through the pipe walls – assume the pipe…arrow_forward
- Determine the heat flow between the roof and floor of 4 x 3 m size of a furnace of 4 m x 4 m x 3 m size when the roof is at 1200 K and the floor is maintained at 600 K, with the other surfaces non absorbing and reradiating. The surface emissivity of the hotter surface is 0.8 and that of the cooler surface 0.6arrow_forwardThe temperature of a cylindrical tank containing liquid nitrogen is -10 ° C. Tank diameter is 16 cm. The amount of heat lost by convection and radiation from the tank to the environment is 65.5 W / m. Calculate the temperature of the environment where the tank is located: h = 4.35 W / m2K, ∈ = 1.arrow_forwardHow does a fin enhance heat transfer at a surface?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license