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
Mineral wool, k = 0.04250 mm18 °C8 °Cq″ = ?

A wall of mineral wool is 250 mm thick and has an area of 20 m². Its faces are held at 18 °C and 8 °C. Find the heat flux q″ through the wall.

k = 0.04 W/(m·K)L = 250 mmA = 20 m²T1 = 18 °CT2 = 8 °C
q″ = W/m²
2.Easy
Gypsum board, k = 0.17200 mm15 °C-11 °Cq″ = ?

A wall of gypsum board is 200 mm thick and has an area of 15 m². Its faces are held at 15 °C and -11 °C. Find the heat flux q″ through the wall.

k = 0.17 W/(m·K)L = 200 mmA = 15 m²T1 = 15 °CT2 = -11 °C
q″ = W/m²
3.Medium
Glass, k = 0.96200 mmBrick, k = 0.7250 mm17 °C3 °CTi​ = ?Q̇

A wall is made of 200 mm of glass and 50 mm of brick, with an area of 12 m². The outer faces are at 17 °C and 3 °C. Find the temperature Ti at the interface between the two layers.

L1 = 200 mm, k1 = 0.96 W/(m·K)L2 = 50 mm, k2 = 0.72 W/(m·K)A = 12 m²T1 = 17 °CT3 = 3 °C
Ti = °C
4.Medium
Brick, k = 0.72150 mmExpanded polystyrene, k = 0.03525 mm17 °C-12 °CTi​ = ?Q̇

A wall is made of 150 mm of brick and 25 mm of expanded polystyrene, with an area of 20 m². The outer faces are at 17 °C and -12 °C. Find the temperature Ti at the interface between the two layers.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 0.035 W/(m·K)A = 20 m²T1 = 17 °CT3 = -12 °C
Ti = °C
5.Hard
Concrete, k = 1.4250 mmBrick, k = 0.7250 mmroom 22 °Coutside -15 °CQ̇

A wall of 250 mm concrete and 50 mm brick separates a room at 22 °C from outside air at -15 °C. The convection coefficients are 8 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 20 m². Find the overall heat transfer coefficient U of the wall.

L1 = 250 mm, k1 = 1.4 W/(m·K)L2 = 50 mm, k2 = 0.72 W/(m·K)A = 20 m²hi = 8 W/(m²·K)ho = 30 W/(m²·K)Troom = 22 °CTout = -15 °C
U = W/(m²·K)
6.Hard
Brick, k = 0.72250 mmGypsum board, k = 0.1775 mmroom 21 °Coutside 3 °CQ̇ = ?

A wall of 250 mm brick and 75 mm gypsum board separates a room at 21 °C from outside air at 3 °C. The convection coefficients are 6 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 8 m². Find the heat loss Q̇ through the wall.

L1 = 250 mm, k1 = 0.72 W/(m·K)L2 = 75 mm, k2 = 0.17 W/(m·K)A = 8 m²hi = 6 W/(m²·K)ho = 30 W/(m²·K)Troom = 21 °CTout = 3 °C
Q̇ = W

Answer key

  1. 1. q″ = 1.6 W/m²
  2. 2. q″ = 22.1 W/m²
  3. 3. Ti = 6.5 °C
  4. 4. Ti = 10.45 °C
  5. 5. U = 2.461 W/(m²·K)
  6. 6. Q̇ = 145.7 W

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