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
Mineral wool, k = 0.04150 mm21 °C6 °CQ̇ = ?

A wall of mineral wool is 150 mm thick and has an area of 15 m². Its faces are held at 21 °C and 6 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.04 W/(m·K)L = 150 mmA = 15 m²T1 = 21 °CT2 = 6 °C
Q̇ = W
2.Easy
Wood, k = 0.17200 mm16 °C-12 °Cq″ = ?

A wall of wood is 200 mm thick and has an area of 10 m². Its faces are held at 16 °C and -12 °C. Find the heat flux q″ through the wall.

k = 0.17 W/(m·K)L = 200 mmA = 10 m²T1 = 16 °CT2 = -12 °C
q″ = W/m²
3.Medium
Concrete, k = 1.4100 mmGlass, k = 0.9675 mm22 °C2 °CQ̇ = ?

A wall is made of 100 mm of concrete and 75 mm of glass, with an area of 15 m². The outer faces are at 22 °C and 2 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 1.4 W/(m·K)L2 = 75 mm, k2 = 0.96 W/(m·K)A = 15 m²T1 = 22 °CT3 = 2 °C
Q̇ = W
4.Medium
Glass, k = 0.96250 mmBrick, k = 0.7225 mm15 °C-4 °CTi​ = ?Q̇

A wall is made of 250 mm of glass and 25 mm of brick, with an area of 10 m². The outer faces are at 15 °C and -4 °C. Find the temperature Ti at the interface between the two layers.

L1 = 250 mm, k1 = 0.96 W/(m·K)L2 = 25 mm, k2 = 0.72 W/(m·K)A = 10 m²T1 = 15 °CT3 = -4 °C
Ti = °C
5.Hard
Brick, k = 0.72250 mmExpanded polystyrene, k = 0.03525 mmroom 21 °Coutside -5 °CTs​ = ?Q̇

A wall of 250 mm brick and 25 mm expanded polystyrene separates a room at 21 °C from outside air at -5 °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 = 250 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 0.035 W/(m·K)A = 20 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = -5 °C
Ts = °C
6.Hard
Mineral wool, k = 0.0450 mmBrick, k = 0.7275 mmroom 20 °Coutside -4 °CQ̇ = ?

A wall of 50 mm mineral wool and 75 mm brick separates a room at 20 °C from outside air at -4 °C. The convection coefficients are 8 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 12 m². Find the heat loss Q̇ through the wall.

L1 = 50 mm, k1 = 0.04 W/(m·K)L2 = 75 mm, k2 = 0.72 W/(m·K)A = 12 m²hi = 8 W/(m²·K)ho = 30 W/(m²·K)Troom = 20 °CTout = -4 °C
Q̇ = W

Answer key

  1. 1. Q̇ = 60 W
  2. 2. q″ = 23.8 W/m²
  3. 3. Q̇ = 2006 W
  4. 4. Ti = −1.765 °C
  5. 5. Ts = 18.37 °C
  6. 6. Q̇ = 190.4 W

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