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
Gypsum board, k = 0.17250 mm24 °C-5 °Cq″ = ?

A wall of gypsum board is 250 mm thick and has an area of 20 m². Its faces are held at 24 °C and -5 °C. Find the heat flux q″ through the wall.

k = 0.17 W/(m·K)L = 250 mmA = 20 m²T1 = 24 °CT2 = -5 °C
q″ = W/m²
2.Easy
Concrete, k = 1.420 mm18 °C5 °CQ̇ = ?

A wall of concrete is 20 mm thick and has an area of 20 m². Its faces are held at 18 °C and 5 °C. Find the rate of heat conduction Q̇ through the wall.

k = 1.4 W/(m·K)L = 20 mmA = 20 m²T1 = 18 °CT2 = 5 °C
Q̇ = W
3.Medium
Brick, k = 0.72100 mmConcrete, k = 1.425 mm15 °C10 °CQ̇ = ?

A wall is made of 100 mm of brick and 25 mm of concrete, with an area of 6 m². The outer faces are at 15 °C and 10 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 1.4 W/(m·K)A = 6 m²T1 = 15 °CT3 = 10 °C
Q̇ = W
4.Medium
Mineral wool, k = 0.04200 mmGlass, k = 0.9625 mm19 °C-11 °CTi​ = ?Q̇

A wall is made of 200 mm of mineral wool and 25 mm of glass, with an area of 12 m². The outer faces are at 19 °C and -11 °C. Find the temperature Ti at the interface between the two layers.

L1 = 200 mm, k1 = 0.04 W/(m·K)L2 = 25 mm, k2 = 0.96 W/(m·K)A = 12 m²T1 = 19 °CT3 = -11 °C
Ti = °C
5.Hard
Glass, k = 0.96100 mmConcrete, k = 1.4150 mmroom 21 °Coutside 3 °CQ̇

A wall of 100 mm glass and 150 mm concrete separates a room at 21 °C from outside air at 3 °C. The convection coefficients are 7.7 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 8 m². Find the overall heat transfer coefficient U of the wall.

L1 = 100 mm, k1 = 0.96 W/(m·K)L2 = 150 mm, k2 = 1.4 W/(m·K)A = 8 m²hi = 7.7 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = 3 °C
U = W/(m²·K)
6.Hard
Mineral wool, k = 0.04100 mmWood, k = 0.1775 mmroom 21 °Coutside -13 °CTs​ = ?Q̇

A wall of 100 mm mineral wool and 75 mm wood separates a room at 21 °C from outside air at -13 °C. The convection coefficients are 8 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 6 m². Find the temperature Ts of the inside surface of the wall.

L1 = 100 mm, k1 = 0.04 W/(m·K)L2 = 75 mm, k2 = 0.17 W/(m·K)A = 6 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = -13 °C
Ts = °C

Answer key

  1. 1. q″ = 19.72 W/m²
  2. 2. Q̇ = 18200 W
  3. 3. Q̇ = 191.4 W
  4. 4. Ti = −10.84 °C
  5. 5. U = 2.556 W/(m²·K)
  6. 6. Ts = 19.64 °C

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