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
Wood, k = 0.17150 mm17 °C3 °CQ̇ = ?

A wall of wood is 150 mm thick and has an area of 15 m². Its faces are held at 17 °C and 3 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.17 W/(m·K)L = 150 mmA = 15 m²T1 = 17 °CT2 = 3 °C
Q̇ = W
2.Easy
Brick, k = 0.72150 mm15 °C3 °CQ̇ = ?

A wall of brick is 150 mm thick and has an area of 4 m². Its faces are held at 15 °C and 3 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 150 mmA = 4 m²T1 = 15 °CT2 = 3 °C
Q̇ = W
3.Medium
Glass, k = 0.96200 mmMineral wool, k = 0.04150 mm22 °C-9 °CTi​ = ?Q̇

A wall is made of 200 mm of glass and 150 mm of mineral wool, with an area of 6 m². The outer faces are at 22 °C and -9 °C. Find the temperature Ti at the interface between the two layers.

L1 = 200 mm, k1 = 0.96 W/(m·K)L2 = 150 mm, k2 = 0.04 W/(m·K)A = 6 m²T1 = 22 °CT3 = -9 °C
Ti = °C
4.Medium
Gypsum board, k = 0.17200 mmBrick, k = 0.7250 mm24 °C-8 °CTi​ = ?Q̇

A wall is made of 200 mm of gypsum board and 50 mm of brick, with an area of 15 m². The outer faces are at 24 °C and -8 °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 = 0.72 W/(m·K)A = 15 m²T1 = 24 °CT3 = -8 °C
Ti = °C
5.Hard
Gypsum board, k = 0.17250 mmWood, k = 0.17100 mmroom 22 °Coutside -6 °CQ̇

A wall of 250 mm gypsum board and 100 mm wood separates a room at 22 °C from outside air at -6 °C. The convection coefficients are 10 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 15 m². Find the overall heat transfer coefficient U of the wall.

L1 = 250 mm, k1 = 0.17 W/(m·K)L2 = 100 mm, k2 = 0.17 W/(m·K)A = 15 m²hi = 10 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -6 °C
U = W/(m²·K)
6.Hard
Brick, k = 0.72150 mmWood, k = 0.1750 mmroom 21 °Coutside 1 °CTs​ = ?Q̇

A wall of 150 mm brick and 50 mm wood separates a room at 21 °C from outside air at 1 °C. The convection coefficients are 8 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 20 m². Find the temperature Ts of the inside surface of the wall.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 50 mm, k2 = 0.17 W/(m·K)A = 20 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = 1 °C
Ts = °C

Answer key

  1. 1. Q̇ = 238 W
  2. 2. Q̇ = 230.4 W
  3. 3. Ti = 20.37 °C
  4. 4. Ti = −6.216 °C
  5. 5. U = 0.4527 W/(m²·K)
  6. 6. Ts = 17.31 °C

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