(III) Suppose the insulating qualities of the wall of a housecome mainly from a 4.0-in.layer of brick and an R-19layer of insulation, as shownin Fig. 14–19. What is the totalrate of heat loss through T,such a wall, if its total area is195 ft? and the temperatureBrick Insulation(R¡)(R2)T1Heatflowdifference across it is 35 F°?FIGURE 14–19Problem 45. Two layersinsulating a wall.

R value of the brick is Thermal conductivity of brick is 0.84 J/m·s°C R=lk=4 in0.84…

Answered: (III) Suppose the insulating qualities…

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.33P

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Question 1: A glass window of width W = 1 m and height H = 2m is 5 mm thick and has a thermal conductivity of kg =1.4 W/m.K. If the inner and outer surface temperatures of the glass are 15 °C and -20 C, respectively, on a cold winter day, what is the rate of heat loss through the glass? To reduce heat loss through windows, it is customary to use a double pane construction in which adjoining panes are separated by an air space. If the spacing is 10 mm and the glass surfaces in contact with the air have temperatures of (last two digit of your Registration number) °C and -15 °C, what is the rate of heat loss from a 1 mx2mwindow? The thermal conductivity of air is ka = 0.024 W/m.K.

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