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 = 0.1720 mm23 °C-4 °Cq″ = ?

A wall of wood is 20 mm thick and has an area of 15 m². Its faces are held at 23 °C and -4 °C. Find the heat flux q″ through the wall.

k = 0.17 W/(m·K)L = 20 mmA = 15 m²T1 = 23 °CT2 = -4 °C
q″ = W/m²
2.Easy
Brick, k = 0.72150 mm19 °C-11 °Cq″ = ?

A wall of brick is 150 mm thick and has an area of 10 m². Its faces are held at 19 °C and -11 °C. Find the heat flux q″ through the wall.

k = 0.72 W/(m·K)L = 150 mmA = 10 m²T1 = 19 °CT2 = -11 °C
q″ = W/m²
3.Medium
Brick, k = 0.72250 mmGlass, k = 0.96150 mm20 °C8 °CQ̇ = ?

A wall is made of 250 mm of brick and 150 mm of glass, with an area of 6 m². The outer faces are at 20 °C and 8 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 0.72 W/(m·K)L2 = 150 mm, k2 = 0.96 W/(m·K)A = 6 m²T1 = 20 °CT3 = 8 °C
Q̇ = W
4.Medium
Brick, k = 0.72100 mmWood, k = 0.1725 mm24 °C-15 °CQ̇ = ?

A wall is made of 100 mm of brick and 25 mm of wood, with an area of 4 m². The outer faces are at 24 °C and -15 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 0.17 W/(m·K)A = 4 m²T1 = 24 °CT3 = -15 °C
Q̇ = W
5.Hard
Brick, k = 0.72150 mmWood, k = 0.17100 mmroom 22 °Coutside 0 °CQ̇

A wall of 150 mm brick and 100 mm wood separates a room at 22 °C from outside air at 0 °C. The convection coefficients are 6 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 4 m². Find the overall heat transfer coefficient U of the wall.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 100 mm, k2 = 0.17 W/(m·K)A = 4 m²hi = 6 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = 0 °C
U = W/(m²·K)
6.Hard
Brick, k = 0.72200 mmGypsum board, k = 0.1775 mmroom 20 °Coutside -1 °CQ̇ = ?

A wall of 200 mm brick and 75 mm gypsum board separates a room at 20 °C from outside air at -1 °C. The convection coefficients are 7.7 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 20 m². Find the heat loss Q̇ through the wall.

L1 = 200 mm, k1 = 0.72 W/(m·K)L2 = 75 mm, k2 = 0.17 W/(m·K)A = 20 m²hi = 7.7 W/(m²·K)ho = 30 W/(m²·K)Troom = 20 °CTout = -1 °C
Q̇ = W

Answer key

  1. 1. q″ = 229.5 W/m²
  2. 2. q″ = 144 W/m²
  3. 3. Q̇ = 143 W
  4. 4. Q̇ = 545.6 W
  5. 5. U = 0.9968 W/(m²·K)
  6. 6. Q̇ = 476.1 W

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