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 = 0.0450 mm25 °C7 °CQ̇ = ?

A wall of mineral wool is 50 mm thick and has an area of 8 m². Its faces are held at 25 °C and 7 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.04 W/(m·K)L = 50 mmA = 8 m²T1 = 25 °CT2 = 7 °C
Q̇ = W
2.Easy
Wood, k = 0.17100 mm23 °C-1 °CQ̇ = ?

A wall of wood is 100 mm thick and has an area of 6 m². Its faces are held at 23 °C and -1 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.17 W/(m·K)L = 100 mmA = 6 m²T1 = 23 °CT2 = -1 °C
Q̇ = W
3.Medium
Concrete, k = 1.4250 mmBrick, k = 0.72150 mm19 °C1 °CQ̇ = ?

A wall is made of 250 mm of concrete and 150 mm of brick, with an area of 15 m². The outer faces are at 19 °C and 1 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 1.4 W/(m·K)L2 = 150 mm, k2 = 0.72 W/(m·K)A = 15 m²T1 = 19 °CT3 = 1 °C
Q̇ = W
4.Medium
Wood, k = 0.17250 mmMineral wool, k = 0.04100 mm18 °C-8 °CTi​ = ?Q̇

A wall is made of 250 mm of wood and 100 mm of mineral wool, with an area of 12 m². The outer faces are at 18 °C and -8 °C. Find the temperature Ti at the interface between the two layers.

L1 = 250 mm, k1 = 0.17 W/(m·K)L2 = 100 mm, k2 = 0.04 W/(m·K)A = 12 m²T1 = 18 °CT3 = -8 °C
Ti = °C
5.Hard
Concrete, k = 1.450 mmGlass, k = 0.9625 mmroom 22 °Coutside -11 °CQ̇ = ?

A wall of 50 mm concrete and 25 mm glass separates a room at 22 °C from outside air at -11 °C. The convection coefficients are 10 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 15 m². Find the heat loss Q̇ through the wall.

L1 = 50 mm, k1 = 1.4 W/(m·K)L2 = 25 mm, k2 = 0.96 W/(m·K)A = 15 m²hi = 10 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = -11 °C
Q̇ = W
6.Hard
Glass, k = 0.96100 mmBrick, k = 0.72150 mmroom 20 °Coutside -9 °CTs​ = ?Q̇

A wall of 100 mm glass and 150 mm brick separates a room at 20 °C from outside air at -9 °C. The convection coefficients are 6 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 = 0.96 W/(m·K)L2 = 150 mm, k2 = 0.72 W/(m·K)A = 6 m²hi = 6 W/(m²·K)ho = 20 W/(m²·K)Troom = 20 °CTout = -9 °C
Ts = °C

Answer key

  1. 1. Q̇ = 115.2 W
  2. 2. Q̇ = 244.8 W
  3. 3. Q̇ = 697.8 W
  4. 4. Ti = 8.37 °C
  5. 5. Q̇ = 2453 W
  6. 6. Ts = 10.87 °C

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