Q2/ A thermopane window consists of two pieces of glass 7 mm thick that enclose an air space 7mm thick. The window separates room air at 20°C from outside ambient air at -10°C. Theconvection coefficient associated with the inner (room-side) surface is 10 W/m2 K.If the convection coefficient associated with the outer (ambient) air is 80 W/m? K, what isthe heat loss through a window that is 0.8 m long by 0.5 m wide? Neglect radiation,[ kglass 1.4W/m-K: kair -0.024S W/m-K)- Window, 0,8 m x 0.5 mIII L0.007 mGlass LLAir ||!T- 20 °Ch= 10 W/m2 KAirTo-10 °Cho = 80 W/m2.KAir

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Q2/ A thermopane window consists of two pieces of glass 7 mm thick that enclose an air space 7 mm thick. The window separates room air at 20°C from outside ambient air at -10°C. The convection coefficient associated with the inner (room-side) surface is 10 W/m K. Ifthe convection coefficient associated with the outer (ambient) air is 80 W/m? K, what is the heat loss through a window that is 0.8 m long by 0,5 m wide? Neglect radiation,[ kglass 1.4 W/m-K: kair -0.0245 W/m-K] - Window, 0.8 m x 0.5 m Glass Air !! Tmi 20 °C hi= 10 Wim2 K Air1I L=0.007 m To-10 °C ho 80 W/m2-K Air

Q2/ A thermopane window consists of two pieces of glass 7 mm thick that enclose an air space 7 mm thick. The window separates room air at 20°C from outside ambient air at -10°C. The convection coefficient associated with the inner (room-side) surface is 10 W/m K. Ifthe convection coefficient associated with the outer (ambient) air is 80 W/m? K, what is the heat loss through a window that is 0.8 m long by 0,5 m wide? Neglect radiation,[ kglass 1.4 W/m-K: kair -0.0245 W/m-K] - Window, 0.8 m x 0.5 m Glass Air !! Tmi 20 °C hi= 10 Wim2 K Air1I L=0.007 m To-10 °C ho 80 W/m2-K Air

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.68P

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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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Question 1: A glass window of width W = 1 m and height H = 2 m 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 oC and -20 oC, 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 20 oC and -15 oC, what is the rate of heat loss from a 1 m x 2 m window? The thermal conductivity of air is ka = 0.024 W/m.K.
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