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 = 0.7220 mm24 °C4 °CQ̇ = ?

A wall of brick is 20 mm thick and has an area of 15 m². Its faces are held at 24 °C and 4 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 20 mmA = 15 m²T1 = 24 °CT2 = 4 °C
Q̇ = W
2.Easy
Brick, k = 0.72150 mm15 °C4 °CQ̇ = ?

A wall of brick is 150 mm thick and has an area of 6 m². Its faces are held at 15 °C and 4 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 150 mmA = 6 m²T1 = 15 °CT2 = 4 °C
Q̇ = W
3.Medium
Gypsum board, k = 0.17200 mmGlass, k = 0.9650 mm25 °C7 °CTi​ = ?Q̇

A wall is made of 200 mm of gypsum board and 50 mm of glass, with an area of 15 m². The outer faces are at 25 °C and 7 °C. Find the temperature Ti at the interface between the two layers.

L1 = 200 mm, k1 = 0.17 W/(m·K)L2 = 50 mm, k2 = 0.96 W/(m·K)A = 15 m²T1 = 25 °CT3 = 7 °C
Ti = °C
4.Medium
Wood, k = 0.17150 mmMineral wool, k = 0.0475 mm23 °C3 °CQ̇ = ?

A wall is made of 150 mm of wood and 75 mm of mineral wool, with an area of 15 m². The outer faces are at 23 °C and 3 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.17 W/(m·K)L2 = 75 mm, k2 = 0.04 W/(m·K)A = 15 m²T1 = 23 °CT3 = 3 °C
Q̇ = W
5.Hard
Glass, k = 0.9650 mmConcrete, k = 1.475 mmroom 20 °Coutside -13 °CQ̇

A wall of 50 mm glass and 75 mm concrete separates a room at 20 °C from outside air at -13 °C. The convection coefficients are 10 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 20 m². Find the overall heat transfer coefficient U of the wall.

L1 = 50 mm, k1 = 0.96 W/(m·K)L2 = 75 mm, k2 = 1.4 W/(m·K)A = 20 m²hi = 10 W/(m²·K)ho = 25 W/(m²·K)Troom = 20 °CTout = -13 °C
U = W/(m²·K)
6.Hard
Wood, k = 0.17100 mmGypsum board, k = 0.1750 mmroom 22 °Coutside -9 °CQ̇ = ?

A wall of 100 mm wood and 50 mm gypsum board separates a room at 22 °C from outside air at -9 °C. The convection coefficients are 8 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 8 m². Find the heat loss Q̇ through the wall.

L1 = 100 mm, k1 = 0.17 W/(m·K)L2 = 50 mm, k2 = 0.17 W/(m·K)A = 8 m²hi = 8 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = -9 °C
Q̇ = W

Answer key

  1. 1. Q̇ = 10800 W
  2. 2. Q̇ = 316.8 W
  3. 3. Ti = 7.763 °C
  4. 4. Q̇ = 108.8 W
  5. 5. U = 4.071 W/(m²·K)
  6. 6. Q̇ = 236.8 W

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