A wall of gypsum board is 200 mm thick and has an area of 20 m². Its faces are held at 25 °C and -10 °C. Find the heat flux q″ through the wall.
Heat conduction worksheet with answers
A wall of glass is 50 mm thick and has an area of 20 m². Its faces are held at 19 °C and -2 °C. Find the rate of heat conduction Q̇ through the wall.
A wall is made of 150 mm of mineral wool and 75 mm of gypsum board, with an area of 8 m². The outer faces are at 25 °C and -10 °C. Find the temperature Ti at the interface between the two layers.
A wall is made of 200 mm of expanded polystyrene and 100 mm of brick, with an area of 20 m². The outer faces are at 23 °C and 9 °C. Find the temperature Ti at the interface between the two layers.
A wall of 50 mm wood and 50 mm brick separates a room at 21 °C from outside air at 3 °C. The convection coefficients are 10 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 4 m². Find the temperature Ts of the inside surface of the wall.
A wall of 50 mm concrete and 150 mm gypsum board separates a room at 22 °C from outside air at -14 °C. The convection coefficients are 6 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 8 m². Find the temperature Ts of the inside surface of the wall.
Answer key
- 1. q″ = 29.75 W/m²
- 2. Q̇ = 8064 W
- 3. Ti = −6.316 °C
- 4. Ti = 9.332 °C
- 5. Ts = 17.43 °C
- 6. Ts = 16.67 °C
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