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 °C7 °CQ̇ = ?

A wall of gypsum board is 250 mm thick and has an area of 10 m². Its faces are held at 24 °C and 7 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.17 W/(m·K)L = 250 mmA = 10 m²T1 = 24 °CT2 = 7 °C
Q̇ = W
2.Easy
Mineral wool, k = 0.0420 mm22 °C-6 °CQ̇ = ?

A wall of mineral wool is 20 mm thick and has an area of 20 m². Its faces are held at 22 °C and -6 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.04 W/(m·K)L = 20 mmA = 20 m²T1 = 22 °CT2 = -6 °C
Q̇ = W
3.Medium
Glass, k = 0.9650 mmExpanded polystyrene, k = 0.03525 mm22 °C7 °CQ̇ = ?

A wall is made of 50 mm of glass and 25 mm of expanded polystyrene, with an area of 4 m². The outer faces are at 22 °C and 7 °C. Find the heat flow Q̇ through the wall.

L1 = 50 mm, k1 = 0.96 W/(m·K)L2 = 25 mm, k2 = 0.035 W/(m·K)A = 4 m²T1 = 22 °CT3 = 7 °C
Q̇ = W
4.Medium
Mineral wool, k = 0.04100 mmWood, k = 0.1750 mm19 °C5 °CQ̇ = ?

A wall is made of 100 mm of mineral wool and 50 mm of wood, with an area of 15 m². The outer faces are at 19 °C and 5 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 0.04 W/(m·K)L2 = 50 mm, k2 = 0.17 W/(m·K)A = 15 m²T1 = 19 °CT3 = 5 °C
Q̇ = W
5.Hard
Glass, k = 0.96100 mmMineral wool, k = 0.0425 mmroom 21 °Coutside -4 °CQ̇

A wall of 100 mm glass and 25 mm mineral wool separates a room at 21 °C from outside air at -4 °C. The convection coefficients are 6 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 = 100 mm, k1 = 0.96 W/(m·K)L2 = 25 mm, k2 = 0.04 W/(m·K)A = 20 m²hi = 6 W/(m²·K)ho = 30 W/(m²·K)Troom = 21 °CTout = -4 °C
U = W/(m²·K)
6.Hard
Concrete, k = 1.4200 mmBrick, k = 0.7250 mmroom 20 °Coutside -2 °CTs​ = ?Q̇

A wall of 200 mm concrete and 50 mm brick separates a room at 20 °C from outside air at -2 °C. The convection coefficients are 10 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 20 m². Find the temperature Ts of the inside surface of the wall.

L1 = 200 mm, k1 = 1.4 W/(m·K)L2 = 50 mm, k2 = 0.72 W/(m·K)A = 20 m²hi = 10 W/(m²·K)ho = 30 W/(m²·K)Troom = 20 °CTout = -2 °C
Ts = °C

Answer key

  1. 1. Q̇ = 115.6 W
  2. 2. Q̇ = 1120 W
  3. 3. Q̇ = 78.29 W
  4. 4. Q̇ = 75.16 W
  5. 5. U = 1.076 W/(m²·K)
  6. 6. Ts = 13.63 °C

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