Heat conduction worksheet with answers

Free printable Heat conduction worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
Gypsum board, k = 0.17100 mm17 °C6 °CQ̇ = ?

A wall of gypsum board is 100 mm thick and has an area of 15 m². Its faces are held at 17 °C and 6 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.17 W/(m·K)L = 100 mmA = 15 m²T1 = 17 °CT2 = 6 °C
Q̇ = W
2.Easy
Glass, k = 0.96200 mm25 °C-8 °Cq″ = ?

A wall of glass is 200 mm thick and has an area of 8 m². Its faces are held at 25 °C and -8 °C. Find the heat flux q″ through the wall.

k = 0.96 W/(m·K)L = 200 mmA = 8 m²T1 = 25 °CT2 = -8 °C
q″ = W/m²
3.Medium
Mineral wool, k = 0.04150 mmGypsum board, k = 0.1725 mm22 °C-9 °CQ̇ = ?

A wall is made of 150 mm of mineral wool and 25 mm of gypsum board, with an area of 15 m². The outer faces are at 22 °C and -9 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.04 W/(m·K)L2 = 25 mm, k2 = 0.17 W/(m·K)A = 15 m²T1 = 22 °CT3 = -9 °C
Q̇ = W
4.Medium
Brick, k = 0.72100 mmMineral wool, k = 0.0425 mm25 °C-6 °CTi​ = ?Q̇

A wall is made of 100 mm of brick and 25 mm of mineral wool, with an area of 8 m². The outer faces are at 25 °C and -6 °C. Find the temperature Ti at the interface between the two layers.

L1 = 100 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 0.04 W/(m·K)A = 8 m²T1 = 25 °CT3 = -6 °C
Ti = °C
5.Hard
Brick, k = 0.72200 mmExpanded polystyrene, k = 0.035150 mmroom 20 °Coutside -3 °CQ̇

A wall of 200 mm brick and 150 mm expanded polystyrene separates a room at 20 °C from outside air at -3 °C. The convection coefficients are 6 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 12 m². Find the overall heat transfer coefficient U of the wall.

L1 = 200 mm, k1 = 0.72 W/(m·K)L2 = 150 mm, k2 = 0.035 W/(m·K)A = 12 m²hi = 6 W/(m²·K)ho = 20 W/(m²·K)Troom = 20 °CTout = -3 °C
U = W/(m²·K)
6.Hard
Glass, k = 0.96200 mmGypsum board, k = 0.1775 mmroom 21 °Coutside -5 °CQ̇

A wall of 200 mm glass and 75 mm gypsum board separates a room at 21 °C from outside air at -5 °C. The convection coefficients are 10 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 15 m². Find the overall heat transfer coefficient U of the wall.

L1 = 200 mm, k1 = 0.96 W/(m·K)L2 = 75 mm, k2 = 0.17 W/(m·K)A = 15 m²hi = 10 W/(m²·K)ho = 30 W/(m²·K)Troom = 21 °CTout = -5 °C
U = W/(m²·K)

Answer key

  1. 1. Q̇ = 280.5 W
  2. 2. q″ = 158.4 W/m²
  3. 3. Q̇ = 119.3 W
  4. 4. Ti = 19.36 °C
  5. 5. U = 0.2092 W/(m²·K)
  6. 6. U = 1.277 W/(m²·K)

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