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
Expanded polystyrene, k = 0.03510 mm15 °C1 °CQ̇ = ?

A wall of expanded polystyrene is 10 mm thick and has an area of 20 m². Its faces are held at 15 °C and 1 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.035 W/(m·K)L = 10 mmA = 20 m²T1 = 15 °CT2 = 1 °C
Q̇ = W
2.Easy
Wood, k = 0.17200 mm25 °C4 °CQ̇ = ?

A wall of wood is 200 mm thick and has an area of 8 m². Its faces are held at 25 °C and 4 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.17 W/(m·K)L = 200 mmA = 8 m²T1 = 25 °CT2 = 4 °C
Q̇ = W
3.Medium
Glass, k = 0.96100 mmBrick, k = 0.7275 mm23 °C10 °CQ̇ = ?

A wall is made of 100 mm of glass and 75 mm of brick, with an area of 8 m². The outer faces are at 23 °C and 10 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 0.96 W/(m·K)L2 = 75 mm, k2 = 0.72 W/(m·K)A = 8 m²T1 = 23 °CT3 = 10 °C
Q̇ = W
4.Medium
Concrete, k = 1.4200 mmExpanded polystyrene, k = 0.03550 mm20 °C-14 °CQ̇ = ?

A wall is made of 200 mm of concrete and 50 mm of expanded polystyrene, with an area of 12 m². The outer faces are at 20 °C and -14 °C. Find the heat flow Q̇ through the wall.

L1 = 200 mm, k1 = 1.4 W/(m·K)L2 = 50 mm, k2 = 0.035 W/(m·K)A = 12 m²T1 = 20 °CT3 = -14 °C
Q̇ = W
5.Hard
Expanded polystyrene, k = 0.035150 mmWood, k = 0.1725 mmroom 21 °Coutside 1 °CQ̇ = ?

A wall of 150 mm expanded polystyrene and 25 mm wood separates a room at 21 °C from outside air at 1 °C. The convection coefficients are 10 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 8 m². Find the heat loss Q̇ through the wall.

L1 = 150 mm, k1 = 0.035 W/(m·K)L2 = 25 mm, k2 = 0.17 W/(m·K)A = 8 m²hi = 10 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = 1 °C
Q̇ = W
6.Hard
Brick, k = 0.72250 mmMineral wool, k = 0.04100 mmroom 22 °Coutside 0 °CTs​ = ?Q̇

A wall of 250 mm brick and 100 mm mineral wool separates a room at 22 °C from outside air at 0 °C. The convection coefficients are 6 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 10 m². Find the temperature Ts of the inside surface of the wall.

L1 = 250 mm, k1 = 0.72 W/(m·K)L2 = 100 mm, k2 = 0.04 W/(m·K)A = 10 m²hi = 6 W/(m²·K)ho = 30 W/(m²·K)Troom = 22 °CTout = 0 °C
Ts = °C

Answer key

  1. 1. Q̇ = 980 W
  2. 2. Q̇ = 142.8 W
  3. 3. Q̇ = 499.2 W
  4. 4. Q̇ = 259.6 W
  5. 5. Q̇ = 34.91 W
  6. 6. Ts = 20.8 °C

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