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 = 0.035100 mm22 °C-9 °CQ̇ = ?

A wall of expanded polystyrene is 100 mm thick and has an area of 10 m². Its faces are held at 22 °C and -9 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.035 W/(m·K)L = 100 mmA = 10 m²T1 = 22 °CT2 = -9 °C
Q̇ = W
2.Easy
Expanded polystyrene, k = 0.03520 mm24 °C-10 °CQ̇ = ?

A wall of expanded polystyrene is 20 mm thick and has an area of 4 m². Its faces are held at 24 °C and -10 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.035 W/(m·K)L = 20 mmA = 4 m²T1 = 24 °CT2 = -10 °C
Q̇ = W
3.Medium
Brick, k = 0.72150 mmMineral wool, k = 0.04100 mm15 °C2 °CQ̇ = ?

A wall is made of 150 mm of brick and 100 mm of mineral wool, with an area of 12 m². The outer faces are at 15 °C and 2 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 100 mm, k2 = 0.04 W/(m·K)A = 12 m²T1 = 15 °CT3 = 2 °C
Q̇ = W
4.Medium
Mineral wool, k = 0.04250 mmBrick, k = 0.7275 mm22 °C-1 °CQ̇ = ?

A wall is made of 250 mm of mineral wool and 75 mm of brick, with an area of 20 m². The outer faces are at 22 °C and -1 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 0.04 W/(m·K)L2 = 75 mm, k2 = 0.72 W/(m·K)A = 20 m²T1 = 22 °CT3 = -1 °C
Q̇ = W
5.Hard
Wood, k = 0.17200 mmGypsum board, k = 0.17100 mmroom 22 °Coutside -2 °CQ̇

A wall of 200 mm wood and 100 mm gypsum board separates a room at 22 °C from outside air at -2 °C. The convection coefficients are 7.7 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 8 m². Find the overall heat transfer coefficient U of the wall.

L1 = 200 mm, k1 = 0.17 W/(m·K)L2 = 100 mm, k2 = 0.17 W/(m·K)A = 8 m²hi = 7.7 W/(m²·K)ho = 30 W/(m²·K)Troom = 22 °CTout = -2 °C
U = W/(m²·K)
6.Hard
Wood, k = 0.1750 mmConcrete, k = 1.4150 mmroom 22 °Coutside -9 °CQ̇

A wall of 50 mm wood and 150 mm concrete separates a room at 22 °C from outside air at -9 °C. The convection coefficients are 10 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 10 m². Find the overall heat transfer coefficient U of the wall.

L1 = 50 mm, k1 = 0.17 W/(m·K)L2 = 150 mm, k2 = 1.4 W/(m·K)A = 10 m²hi = 10 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -9 °C
U = W/(m²·K)

Answer key

  1. 1. Q̇ = 108.5 W
  2. 2. Q̇ = 238 W
  3. 3. Q̇ = 57.6 W
  4. 4. Q̇ = 72.39 W
  5. 5. U = 0.5187 W/(m²·K)
  6. 6. U = 1.814 W/(m²·K)

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