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 °C-8 °Cq″ = ?

A wall of brick is 10 mm thick and has an area of 10 m². Its faces are held at 18 °C and -8 °C. Find the heat flux q″ through the wall.

k = 0.72 W/(m·K)L = 10 mmA = 10 m²T1 = 18 °CT2 = -8 °C
q″ = W/m²
2.Easy
Concrete, k = 1.4100 mm25 °C0 °Cq″ = ?

A wall of concrete is 100 mm thick and has an area of 20 m². Its faces are held at 25 °C and 0 °C. Find the heat flux q″ through the wall.

k = 1.4 W/(m·K)L = 100 mmA = 20 m²T1 = 25 °CT2 = 0 °C
q″ = W/m²
3.Medium
Mineral wool, k = 0.0450 mmConcrete, k = 1.450 mm20 °C0 °CQ̇ = ?

A wall is made of 50 mm of mineral wool and 50 mm of concrete, with an area of 12 m². The outer faces are at 20 °C and 0 °C. Find the heat flow Q̇ through the wall.

L1 = 50 mm, k1 = 0.04 W/(m·K)L2 = 50 mm, k2 = 1.4 W/(m·K)A = 12 m²T1 = 20 °CT3 = 0 °C
Q̇ = W
4.Medium
Wood, k = 0.17150 mmGlass, k = 0.96100 mm24 °C-13 °CQ̇ = ?

A wall is made of 150 mm of wood and 100 mm of glass, with an area of 8 m². The outer faces are at 24 °C and -13 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.17 W/(m·K)L2 = 100 mm, k2 = 0.96 W/(m·K)A = 8 m²T1 = 24 °CT3 = -13 °C
Q̇ = W
5.Hard
Mineral wool, k = 0.04100 mmExpanded polystyrene, k = 0.035100 mmroom 21 °Coutside -10 °CQ̇

A wall of 100 mm mineral wool and 100 mm expanded polystyrene separates a room at 21 °C from outside air at -10 °C. The convection coefficients are 7.7 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 4 m². Find the overall heat transfer coefficient U of the wall.

L1 = 100 mm, k1 = 0.04 W/(m·K)L2 = 100 mm, k2 = 0.035 W/(m·K)A = 4 m²hi = 7.7 W/(m²·K)ho = 30 W/(m²·K)Troom = 21 °CTout = -10 °C
U = W/(m²·K)
6.Hard
Wood, k = 0.1750 mmGypsum board, k = 0.1775 mmroom 21 °Coutside 1 °CQ̇ = ?

A wall of 50 mm wood and 75 mm gypsum board separates a room at 21 °C from outside air at 1 °C. The convection coefficients are 8 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 20 m². Find the heat loss Q̇ through the wall.

L1 = 50 mm, k1 = 0.17 W/(m·K)L2 = 75 mm, k2 = 0.17 W/(m·K)A = 20 m²hi = 8 W/(m²·K)ho = 25 W/(m²·K)Troom = 21 °CTout = 1 °C
Q̇ = W

Answer key

  1. 1. q″ = 1872 W/m²
  2. 2. q″ = 350 W/m²
  3. 3. Q̇ = 186.7 W
  4. 4. Q̇ = 300 W
  5. 5. U = 0.1811 W/(m²·K)
  6. 6. Q̇ = 444.3 W

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