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 mm21 °C-9 °Cq″ = ?

A wall of brick is 20 mm thick and has an area of 4 m². Its faces are held at 21 °C and -9 °C. Find the heat flux q″ through the wall.

k = 0.72 W/(m·K)L = 20 mmA = 4 m²T1 = 21 °CT2 = -9 °C
q″ = W/m²
2.Easy
Concrete, k = 1.450 mm20 °C3 °CQ̇ = ?

A wall of concrete is 50 mm thick and has an area of 4 m². Its faces are held at 20 °C and 3 °C. Find the rate of heat conduction Q̇ through the wall.

k = 1.4 W/(m·K)L = 50 mmA = 4 m²T1 = 20 °CT2 = 3 °C
Q̇ = W
3.Medium
Wood, k = 0.17100 mmBrick, k = 0.7275 mm19 °C-1 °CQ̇ = ?

A wall is made of 100 mm of wood and 75 mm of brick, with an area of 6 m². The outer faces are at 19 °C and -1 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 0.17 W/(m·K)L2 = 75 mm, k2 = 0.72 W/(m·K)A = 6 m²T1 = 19 °CT3 = -1 °C
Q̇ = W
4.Medium
Glass, k = 0.96200 mmMineral wool, k = 0.04100 mm23 °C-6 °CQ̇ = ?

A wall is made of 200 mm of glass and 100 mm of mineral wool, with an area of 6 m². The outer faces are at 23 °C and -6 °C. Find the heat flow Q̇ through the wall.

L1 = 200 mm, k1 = 0.96 W/(m·K)L2 = 100 mm, k2 = 0.04 W/(m·K)A = 6 m²T1 = 23 °CT3 = -6 °C
Q̇ = W
5.Hard
Concrete, k = 1.4200 mmMineral wool, k = 0.04100 mmroom 22 °Coutside -2 °CQ̇

A wall of 200 mm concrete and 100 mm mineral wool separates a room at 22 °C from outside air at -2 °C. The convection coefficients are 8 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 4 m². Find the overall heat transfer coefficient U of the wall.

L1 = 200 mm, k1 = 1.4 W/(m·K)L2 = 100 mm, k2 = 0.04 W/(m·K)A = 4 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -2 °C
U = W/(m²·K)
6.Hard
Mineral wool, k = 0.04100 mmBrick, k = 0.7250 mmroom 20 °Coutside -14 °CQ̇

A wall of 100 mm mineral wool and 50 mm brick separates a room at 20 °C from outside air at -14 °C. The convection coefficients are 6 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 12 m². Find the overall heat transfer coefficient U of the wall.

L1 = 100 mm, k1 = 0.04 W/(m·K)L2 = 50 mm, k2 = 0.72 W/(m·K)A = 12 m²hi = 6 W/(m²·K)ho = 20 W/(m²·K)Troom = 20 °CTout = -14 °C
U = W/(m²·K)

Answer key

  1. 1. q″ = 1080 W/m²
  2. 2. Q̇ = 1904 W
  3. 3. Q̇ = 173.3 W
  4. 4. Q̇ = 64.25 W
  5. 5. U = 0.3549 W/(m²·K)
  6. 6. U = 0.3589 W/(m²·K)

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