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
Brick, k = 0.72150 mm18 °C-8 °CQ̇ = ?

A wall of brick is 150 mm thick and has an area of 4 m². Its faces are held at 18 °C and -8 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 150 mmA = 4 m²T1 = 18 °CT2 = -8 °C
Q̇ = W
2.Easy
Concrete, k = 1.4200 mm24 °C-2 °CQ̇ = ?

A wall of concrete is 200 mm thick and has an area of 8 m². Its faces are held at 24 °C and -2 °C. Find the rate of heat conduction Q̇ through the wall.

k = 1.4 W/(m·K)L = 200 mmA = 8 m²T1 = 24 °CT2 = -2 °C
Q̇ = W
3.Medium
Expanded polystyrene, k = 0.035150 mmGypsum board, k = 0.17150 mm17 °C-8 °CTi​ = ?Q̇

A wall is made of 150 mm of expanded polystyrene and 150 mm of gypsum board, with an area of 15 m². The outer faces are at 17 °C and -8 °C. Find the temperature Ti at the interface between the two layers.

L1 = 150 mm, k1 = 0.035 W/(m·K)L2 = 150 mm, k2 = 0.17 W/(m·K)A = 15 m²T1 = 17 °CT3 = -8 °C
Ti = °C
4.Medium
Glass, k = 0.9650 mmWood, k = 0.1775 mm16 °C9 °CQ̇ = ?

A wall is made of 50 mm of glass and 75 mm of wood, with an area of 10 m². The outer faces are at 16 °C and 9 °C. Find the heat flow Q̇ through the wall.

L1 = 50 mm, k1 = 0.96 W/(m·K)L2 = 75 mm, k2 = 0.17 W/(m·K)A = 10 m²T1 = 16 °CT3 = 9 °C
Q̇ = W
5.Hard
Brick, k = 0.72150 mmConcrete, k = 1.475 mmroom 21 °Coutside -10 °CQ̇ = ?

A wall of 150 mm brick and 75 mm concrete separates a room at 21 °C from outside air at -10 °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 heat loss Q̇ through the wall.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 75 mm, k2 = 1.4 W/(m·K)A = 12 m²hi = 6 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = -10 °C
Q̇ = W
6.Hard
Wood, k = 0.17100 mmConcrete, k = 1.425 mmroom 22 °Coutside -1 °CQ̇ = ?

A wall of 100 mm wood and 25 mm concrete separates a room at 22 °C from outside air at -1 °C. The convection coefficients are 6 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 4 m². Find the heat loss Q̇ through the wall.

L1 = 100 mm, k1 = 0.17 W/(m·K)L2 = 25 mm, k2 = 1.4 W/(m·K)A = 4 m²hi = 6 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -1 °C
Q̇ = W

Answer key

  1. 1. Q̇ = 499.2 W
  2. 2. Q̇ = 1456 W
  3. 3. Ti = −3.732 °C
  4. 4. Q̇ = 141.9 W
  5. 5. Q̇ = 777.3 W
  6. 6. Q̇ = 111.8 W

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