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
Wood, k = 0.17200 mm21 °C-2 °Cq″ = ?

A wall of wood is 200 mm thick and has an area of 15 m². Its faces are held at 21 °C and -2 °C. Find the heat flux q″ through the wall.

k = 0.17 W/(m·K)L = 200 mmA = 15 m²T1 = 21 °CT2 = -2 °C
q″ = W/m²
2.Easy
Expanded polystyrene, k = 0.035150 mm24 °C-14 °Cq″ = ?

A wall of expanded polystyrene is 150 mm thick and has an area of 10 m². Its faces are held at 24 °C and -14 °C. Find the heat flux q″ through the wall.

k = 0.035 W/(m·K)L = 150 mmA = 10 m²T1 = 24 °CT2 = -14 °C
q″ = W/m²
3.Medium
Wood, k = 0.17200 mmConcrete, k = 1.4100 mm16 °C-7 °CQ̇ = ?

A wall is made of 200 mm of wood and 100 mm of concrete, with an area of 8 m². The outer faces are at 16 °C and -7 °C. Find the heat flow Q̇ through the wall.

L1 = 200 mm, k1 = 0.17 W/(m·K)L2 = 100 mm, k2 = 1.4 W/(m·K)A = 8 m²T1 = 16 °CT3 = -7 °C
Q̇ = W
4.Medium
Wood, k = 0.17250 mmExpanded polystyrene, k = 0.03525 mm19 °C-3 °CQ̇ = ?

A wall is made of 250 mm of wood and 25 mm of expanded polystyrene, with an area of 12 m². The outer faces are at 19 °C and -3 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 0.17 W/(m·K)L2 = 25 mm, k2 = 0.035 W/(m·K)A = 12 m²T1 = 19 °CT3 = -3 °C
Q̇ = W
5.Hard
Brick, k = 0.7250 mmGlass, k = 0.9650 mmroom 22 °Coutside -12 °CQ̇

A wall of 50 mm brick and 50 mm glass separates a room at 22 °C from outside air at -12 °C. The convection coefficients are 10 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 8 m². Find the overall heat transfer coefficient U of the wall.

L1 = 50 mm, k1 = 0.72 W/(m·K)L2 = 50 mm, k2 = 0.96 W/(m·K)A = 8 m²hi = 10 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -12 °C
U = W/(m²·K)
6.Hard
Gypsum board, k = 0.17250 mmExpanded polystyrene, k = 0.035150 mmroom 20 °Coutside -13 °CQ̇ = ?

A wall of 250 mm gypsum board and 150 mm expanded polystyrene separates a room at 20 °C from outside air at -13 °C. The convection coefficients are 6 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 15 m². Find the heat loss Q̇ through the wall.

L1 = 250 mm, k1 = 0.17 W/(m·K)L2 = 150 mm, k2 = 0.035 W/(m·K)A = 15 m²hi = 6 W/(m²·K)ho = 30 W/(m²·K)Troom = 20 °CTout = -13 °C
Q̇ = W

Answer key

  1. 1. q″ = 19.55 W/m²
  2. 2. q″ = 8.867 W/m²
  3. 3. Q̇ = 147.4 W
  4. 4. Q̇ = 120.8 W
  5. 5. U = 3.683 W/(m²·K)
  6. 6. Q̇ = 83.11 W

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