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 = 0.7210 mm18 °C2 °CQ̇ = ?

A wall of brick is 10 mm thick and has an area of 12 m². Its faces are held at 18 °C and 2 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 10 mmA = 12 m²T1 = 18 °CT2 = 2 °C
Q̇ = W
2.Easy
Wood, k = 0.1720 mm24 °C5 °CQ̇ = ?

A wall of wood is 20 mm thick and has an area of 20 m². Its faces are held at 24 °C and 5 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.17 W/(m·K)L = 20 mmA = 20 m²T1 = 24 °CT2 = 5 °C
Q̇ = W
3.Medium
Brick, k = 0.72250 mmWood, k = 0.1725 mm19 °C-14 °CQ̇ = ?

A wall is made of 250 mm of brick and 25 mm of wood, with an area of 12 m². The outer faces are at 19 °C and -14 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 0.17 W/(m·K)A = 12 m²T1 = 19 °CT3 = -14 °C
Q̇ = W
4.Medium
Mineral wool, k = 0.04150 mmExpanded polystyrene, k = 0.035150 mm15 °C4 °CQ̇ = ?

A wall is made of 150 mm of mineral wool and 150 mm of expanded polystyrene, with an area of 6 m². The outer faces are at 15 °C and 4 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.04 W/(m·K)L2 = 150 mm, k2 = 0.035 W/(m·K)A = 6 m²T1 = 15 °CT3 = 4 °C
Q̇ = W
5.Hard
Brick, k = 0.7250 mmGlass, k = 0.96100 mmroom 22 °Coutside 1 °CQ̇

A wall of 50 mm brick and 100 mm glass separates a room at 22 °C from outside air at 1 °C. The convection coefficients are 7.7 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 6 m². Find the overall heat transfer coefficient U of the wall.

L1 = 50 mm, k1 = 0.72 W/(m·K)L2 = 100 mm, k2 = 0.96 W/(m·K)A = 6 m²hi = 7.7 W/(m²·K)ho = 30 W/(m²·K)Troom = 22 °CTout = 1 °C
U = W/(m²·K)
6.Hard
Brick, k = 0.7250 mmExpanded polystyrene, k = 0.035100 mmroom 21 °Coutside 0 °CQ̇

A wall of 50 mm brick and 100 mm expanded polystyrene separates a room at 21 °C from outside air at 0 °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 overall heat transfer coefficient U of the wall.

L1 = 50 mm, k1 = 0.72 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 = 21 °CTout = 0 °C
U = W/(m²·K)

Answer key

  1. 1. Q̇ = 13824 W
  2. 2. Q̇ = 3230 W
  3. 3. Q̇ = 801.2 W
  4. 4. Q̇ = 8.213 W
  5. 5. U = 2.969 W/(m²·K)
  6. 6. U = 0.3229 W/(m²·K)

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