A wall of gypsum board is 100 mm thick and has an area of 8 m². Its faces are held at 17 °C and -8 °C. Find the heat flux q″ through the wall.
Heat conduction worksheet with answers
A wall of mineral wool is 50 mm thick and has an area of 4 m². Its faces are held at 25 °C and 1 °C. Find the rate of heat conduction Q̇ through the wall.
A wall is made of 100 mm of concrete and 150 mm of wood, with an area of 8 m². The outer faces are at 25 °C and 7 °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 wood, with an area of 12 m². The outer faces are at 18 °C and -9 °C. Find the heat flow Q̇ through the wall.
A wall of 50 mm glass and 50 mm gypsum board separates a room at 20 °C from outside air at 0 °C. The convection coefficients are 7.7 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 6 m². Find the overall heat transfer coefficient U of the wall.
A wall of 250 mm glass and 25 mm mineral wool separates a room at 21 °C from outside air at -1 °C. The convection coefficients are 8 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 4 m². Find the overall heat transfer coefficient U of the wall.
Answer key
- 1. q″ = 42.5 W/m²
- 2. Q̇ = 76.8 W
- 3. Ti = 23.65 °C
- 4. Q̇ = 51.41 W
- 5. U = 1.901 W/(m²·K)
- 6. U = 0.952 W/(m²·K)
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