A house has a composite wall of wood, fiberglass insulation, and plaster board, as indicated in the sketch. On a cold winter day, the convection heat transfer coefficients are ho = 60 W/m².K and h; = 20 W/m2.K. The total wall surface area is 500 m². The plaster board thickness is Lp = 10 mm, the glass fiber thickness is L = 100 mm, and the plywood siding thickness is Ls = 20 mm. The temperature inside is T; = 20°C and the temperature outside is T, = -15°C. Determine the total heat loss through the wall. Plaster board, k Inside h;, Too, i 111 Glass fiber blanket (28 kg/m³), kb Lp -Plywood siding, k Outside hos Too, o 111

A house has a composite wall of wood, fiberglass insulation, and plaster board, as indicated in the sketch. On a cold winter day, the convection heat transfer coefficients are ho = 60 W/m².K and h; = 20 W/m2.K. The total wall surface area is 500 m². The plaster board thickness is Lp = 10 mm, the glass fiber thickness is L = 100 mm, and the plywood siding thickness is Ls = 20 mm. The temperature inside is T; = 20°C and the temperature outside is T, = -15°C. Determine the total heat loss through the wall. Plaster board, k Inside h;, Too, i 111 Glass fiber blanket (28 kg/m³), kb Lp -Plywood siding, k Outside hos Too, o 111

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 1.40P: As a designer working for a major electric appliance manufacturer, you are required to estimate the...

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Concept explainers

Conduction and Convection

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a burner, heats up because of the flame underneath it.

Question

a.) Determine the thermal conductivity of the plasterboard (k_p), in W/m*K

b) Determine the value of the inside convection resistance (R_i), in degrees C/W.

c) Determine the value of the fiberglass blanket resistance (R_b), in degrees C/W.

d) Determine the value of total heat transfer resistance (R_total), in degrees C/W.

e) Determine the value of heat loss (q), in kW.

A house has a composite wall of wood, fiberglass insulation, and plaster board, as indicated in the sketch. On a cold winter day, the
convection heat transfer coefficients are ho = 60 W/m².K and h₁ = 20 W/m².K. The total wall surface area is 500 m². The plaster
board thickness is Lp = 10 mm, the glass fiber thickness is L = 100 mm, and the plywood siding thickness is Ls = 20 mm. The
temperature inside is T; = 20°C and the temperature outside is To = -15°C. Determine the total heat loss through the wall.
Plaster board, k
Inside
h;, Too, i
111
Glass fiber blanket
(28 kg/m³), kb
Lp
L₂
Ls
-Plywood siding, k
Outside
ho, Too, o
111

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