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
Glass, k = 0.9620 mm21 °C7 °CQ̇ = ?

A wall of glass is 20 mm thick and has an area of 6 m². Its faces are held at 21 °C and 7 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.96 W/(m·K)L = 20 mmA = 6 m²T1 = 21 °CT2 = 7 °C
Q̇ = W
2.Easy
Brick, k = 0.72250 mm17 °C-15 °CQ̇ = ?

A wall of brick is 250 mm thick and has an area of 20 m². Its faces are held at 17 °C and -15 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 250 mmA = 20 m²T1 = 17 °CT2 = -15 °C
Q̇ = W
3.Medium
Glass, k = 0.96200 mmConcrete, k = 1.4100 mm24 °C3 °CQ̇ = ?

A wall is made of 200 mm of glass and 100 mm of concrete, with an area of 20 m². The outer faces are at 24 °C and 3 °C. Find the heat flow Q̇ through the wall.

L1 = 200 mm, k1 = 0.96 W/(m·K)L2 = 100 mm, k2 = 1.4 W/(m·K)A = 20 m²T1 = 24 °CT3 = 3 °C
Q̇ = W
4.Medium
Gypsum board, k = 0.17100 mmWood, k = 0.1750 mm15 °C-11 °CTi​ = ?Q̇

A wall is made of 100 mm of gypsum board and 50 mm of wood, with an area of 10 m². The outer faces are at 15 °C and -11 °C. Find the temperature Ti at the interface between the two layers.

L1 = 100 mm, k1 = 0.17 W/(m·K)L2 = 50 mm, k2 = 0.17 W/(m·K)A = 10 m²T1 = 15 °CT3 = -11 °C
Ti = °C
5.Hard
Brick, k = 0.7250 mmGlass, k = 0.96100 mmroom 22 °Coutside 1 °CTs​ = ?Q̇

A wall of 50 mm brick and 100 mm glass separates a room at 22 °C from outside air at 1 °C. The convection coefficients are 6 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 12 m². Find the temperature Ts of the inside surface of the wall.

L1 = 50 mm, k1 = 0.72 W/(m·K)L2 = 100 mm, k2 = 0.96 W/(m·K)A = 12 m²hi = 6 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = 1 °C
Ts = °C
6.Hard
Wood, k = 0.17200 mmExpanded polystyrene, k = 0.035150 mmroom 21 °Coutside -14 °CQ̇

A wall of 200 mm wood and 150 mm expanded polystyrene separates a room at 21 °C from outside air at -14 °C. The convection coefficients are 8 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 10 m². Find the overall heat transfer coefficient U of the wall.

L1 = 200 mm, k1 = 0.17 W/(m·K)L2 = 150 mm, k2 = 0.035 W/(m·K)A = 10 m²hi = 8 W/(m²·K)ho = 30 W/(m²·K)Troom = 21 °CTout = -14 °C
U = W/(m²·K)

Answer key

  1. 1. Q̇ = 4032 W
  2. 2. Q̇ = 1843 W
  3. 3. Q̇ = 1501 W
  4. 4. Ti = −2.333 °C
  5. 5. Ts = 12.8 °C
  6. 6. U = 0.1779 W/(m²·K)

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