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
Expanded polystyrene, k = 0.035250 mm21 °C-2 °CQ̇ = ?

A wall of expanded polystyrene is 250 mm thick and has an area of 10 m². Its faces are held at 21 °C and -2 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.035 W/(m·K)L = 250 mmA = 10 m²T1 = 21 °CT2 = -2 °C
Q̇ = W
2.Easy
Expanded polystyrene, k = 0.035200 mm20 °C0 °CQ̇ = ?

A wall of expanded polystyrene is 200 mm thick and has an area of 12 m². Its faces are held at 20 °C and 0 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.035 W/(m·K)L = 200 mmA = 12 m²T1 = 20 °CT2 = 0 °C
Q̇ = W
3.Medium
Glass, k = 0.96150 mmExpanded polystyrene, k = 0.03525 mm19 °C10 °CQ̇ = ?

A wall is made of 150 mm of glass and 25 mm of expanded polystyrene, with an area of 12 m². The outer faces are at 19 °C and 10 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.96 W/(m·K)L2 = 25 mm, k2 = 0.035 W/(m·K)A = 12 m²T1 = 19 °CT3 = 10 °C
Q̇ = W
4.Medium
Brick, k = 0.72250 mmExpanded polystyrene, k = 0.03550 mm18 °C5 °CQ̇ = ?

A wall is made of 250 mm of brick and 50 mm of expanded polystyrene, with an area of 4 m². The outer faces are at 18 °C and 5 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 0.72 W/(m·K)L2 = 50 mm, k2 = 0.035 W/(m·K)A = 4 m²T1 = 18 °CT3 = 5 °C
Q̇ = W
5.Hard
Wood, k = 0.17250 mmMineral wool, k = 0.04100 mmroom 22 °Coutside -9 °CTs​ = ?Q̇

A wall of 250 mm wood and 100 mm mineral wool separates a room at 22 °C from outside air at -9 °C. The convection coefficients are 7.7 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 20 m². Find the temperature Ts of the inside surface of the wall.

L1 = 250 mm, k1 = 0.17 W/(m·K)L2 = 100 mm, k2 = 0.04 W/(m·K)A = 20 m²hi = 7.7 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -9 °C
Ts = °C
6.Hard
Concrete, k = 1.4150 mmExpanded polystyrene, k = 0.035100 mmroom 22 °Coutside -15 °CTs​ = ?Q̇

A wall of 150 mm concrete and 100 mm expanded polystyrene separates a room at 22 °C from outside air at -15 °C. The convection coefficients are 7.7 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 20 m². Find the temperature Ts of the inside surface of the wall.

L1 = 150 mm, k1 = 1.4 W/(m·K)L2 = 100 mm, k2 = 0.035 W/(m·K)A = 20 m²hi = 7.7 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = -15 °C
Ts = °C

Answer key

  1. 1. Q̇ = 32.2 W
  2. 2. Q̇ = 42 W
  3. 3. Q̇ = 124.1 W
  4. 4. Q̇ = 29.28 W
  5. 5. Ts = 21.03 °C
  6. 6. Ts = 20.47 °C

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