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 = 0.96250 mm16 °C-4 °CQ̇ = ?

A wall of glass is 250 mm thick and has an area of 6 m². Its faces are held at 16 °C and -4 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.96 W/(m·K)L = 250 mmA = 6 m²T1 = 16 °CT2 = -4 °C
Q̇ = W
2.Easy
Glass, k = 0.9650 mm15 °C4 °CQ̇ = ?

A wall of glass is 50 mm thick and has an area of 15 m². Its faces are held at 15 °C and 4 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.96 W/(m·K)L = 50 mmA = 15 m²T1 = 15 °CT2 = 4 °C
Q̇ = W
3.Medium
Brick, k = 0.72150 mmGlass, k = 0.9675 mm24 °C8 °CQ̇ = ?

A wall is made of 150 mm of brick and 75 mm of glass, with an area of 15 m². The outer faces are at 24 °C and 8 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 75 mm, k2 = 0.96 W/(m·K)A = 15 m²T1 = 24 °CT3 = 8 °C
Q̇ = W
4.Medium
Expanded polystyrene, k = 0.035200 mmConcrete, k = 1.4100 mm19 °C-12 °CTi​ = ?Q̇

A wall is made of 200 mm of expanded polystyrene and 100 mm of concrete, with an area of 12 m². The outer faces are at 19 °C and -12 °C. Find the temperature Ti at the interface between the two layers.

L1 = 200 mm, k1 = 0.035 W/(m·K)L2 = 100 mm, k2 = 1.4 W/(m·K)A = 12 m²T1 = 19 °CT3 = -12 °C
Ti = °C
5.Hard
Brick, k = 0.72200 mmExpanded polystyrene, k = 0.03575 mmroom 22 °Coutside -11 °CTs​ = ?Q̇

A wall of 200 mm brick and 75 mm expanded polystyrene separates a room at 22 °C from outside air at -11 °C. The convection coefficients are 8 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 15 m². Find the temperature Ts of the inside surface of the wall.

L1 = 200 mm, k1 = 0.72 W/(m·K)L2 = 75 mm, k2 = 0.035 W/(m·K)A = 15 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -11 °C
Ts = °C
6.Hard
Expanded polystyrene, k = 0.035100 mmMineral wool, k = 0.0475 mmroom 21 °Coutside -6 °CQ̇ = ?

A wall of 100 mm expanded polystyrene and 75 mm mineral wool separates a room at 21 °C from outside air at -6 °C. The convection coefficients are 10 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 12 m². Find the heat loss Q̇ through the wall.

L1 = 100 mm, k1 = 0.035 W/(m·K)L2 = 75 mm, k2 = 0.04 W/(m·K)A = 12 m²hi = 10 W/(m²·K)ho = 25 W/(m²·K)Troom = 21 °CTout = -6 °C
Q̇ = W

Answer key

  1. 1. Q̇ = 460.8 W
  2. 2. Q̇ = 3168 W
  3. 3. Q̇ = 837.8 W
  4. 4. Ti = −11.62 °C
  5. 5. Ts = 20.41 °C
  6. 6. Q̇ = 66.5 W

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