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 mm18 °C-11 °Cq″ = ?

A wall of wood is 20 mm thick and has an area of 4 m². Its faces are held at 18 °C and -11 °C. Find the heat flux q″ through the wall.

k = 0.17 W/(m·K)L = 20 mmA = 4 m²T1 = 18 °CT2 = -11 °C
q″ = W/m²
2.Easy
Brick, k = 0.72250 mm15 °C-7 °Cq″ = ?

A wall of brick is 250 mm thick and has an area of 4 m². Its faces are held at 15 °C and -7 °C. Find the heat flux q″ through the wall.

k = 0.72 W/(m·K)L = 250 mmA = 4 m²T1 = 15 °CT2 = -7 °C
q″ = W/m²
3.Medium
Mineral wool, k = 0.04200 mmBrick, k = 0.7275 mm17 °C2 °CQ̇ = ?

A wall is made of 200 mm of mineral wool and 75 mm of brick, with an area of 4 m². The outer faces are at 17 °C and 2 °C. Find the heat flow Q̇ through the wall.

L1 = 200 mm, k1 = 0.04 W/(m·K)L2 = 75 mm, k2 = 0.72 W/(m·K)A = 4 m²T1 = 17 °CT3 = 2 °C
Q̇ = W
4.Medium
Gypsum board, k = 0.17200 mmConcrete, k = 1.425 mm20 °C-4 °CTi​ = ?Q̇

A wall is made of 200 mm of gypsum board and 25 mm of concrete, with an area of 10 m². The outer faces are at 20 °C and -4 °C. Find the temperature Ti at the interface between the two layers.

L1 = 200 mm, k1 = 0.17 W/(m·K)L2 = 25 mm, k2 = 1.4 W/(m·K)A = 10 m²T1 = 20 °CT3 = -4 °C
Ti = °C
5.Hard
Mineral wool, k = 0.04100 mmGypsum board, k = 0.17150 mmroom 22 °Coutside -14 °CQ̇ = ?

A wall of 100 mm mineral wool and 150 mm gypsum board separates a room at 22 °C from outside air at -14 °C. The convection coefficients are 6 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 6 m². Find the heat loss Q̇ through the wall.

L1 = 100 mm, k1 = 0.04 W/(m·K)L2 = 150 mm, k2 = 0.17 W/(m·K)A = 6 m²hi = 6 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = -14 °C
Q̇ = W
6.Hard
Mineral wool, k = 0.04250 mmExpanded polystyrene, k = 0.035150 mmroom 22 °Coutside -13 °CQ̇ = ?

A wall of 250 mm mineral wool and 150 mm expanded polystyrene separates a room at 22 °C from outside air at -13 °C. The convection coefficients are 7.7 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 20 m². Find the heat loss Q̇ through the wall.

L1 = 250 mm, k1 = 0.04 W/(m·K)L2 = 150 mm, k2 = 0.035 W/(m·K)A = 20 m²hi = 7.7 W/(m²·K)ho = 20 W/(m²·K)Troom = 22 °CTout = -13 °C
Q̇ = W

Answer key

  1. 1. q″ = 246.5 W/m²
  2. 2. q″ = 63.36 W/m²
  3. 3. Q̇ = 11.76 W
  4. 4. Ti = −3.641 °C
  5. 5. Q̇ = 60.18 W
  6. 6. Q̇ = 65.33 W

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