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
Brick, k = 0.7210 mm22 °C-5 °CQ̇ = ?

A wall of brick is 10 mm thick and has an area of 10 m². Its faces are held at 22 °C and -5 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.72 W/(m·K)L = 10 mmA = 10 m²T1 = 22 °CT2 = -5 °C
Q̇ = W
2.Easy
Expanded polystyrene, k = 0.035100 mm16 °C-4 °Cq″ = ?

A wall of expanded polystyrene is 100 mm thick and has an area of 12 m². Its faces are held at 16 °C and -4 °C. Find the heat flux q″ through the wall.

k = 0.035 W/(m·K)L = 100 mmA = 12 m²T1 = 16 °CT2 = -4 °C
q″ = W/m²
3.Medium
Glass, k = 0.96150 mmExpanded polystyrene, k = 0.03525 mm19 °C2 °CQ̇ = ?

A wall is made of 150 mm of glass and 25 mm of expanded polystyrene, with an area of 8 m². The outer faces are at 19 °C and 2 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.96 W/(m·K)L2 = 25 mm, k2 = 0.035 W/(m·K)A = 8 m²T1 = 19 °CT3 = 2 °C
Q̇ = W
4.Medium
Glass, k = 0.96150 mmBrick, k = 0.72100 mm20 °C-4 °CQ̇ = ?

A wall is made of 150 mm of glass and 100 mm of brick, with an area of 10 m². The outer faces are at 20 °C and -4 °C. Find the heat flow Q̇ through the wall.

L1 = 150 mm, k1 = 0.96 W/(m·K)L2 = 100 mm, k2 = 0.72 W/(m·K)A = 10 m²T1 = 20 °CT3 = -4 °C
Q̇ = W
5.Hard
Expanded polystyrene, k = 0.035200 mmMineral wool, k = 0.0450 mmroom 20 °Coutside 1 °CQ̇ = ?

A wall of 200 mm expanded polystyrene and 50 mm mineral wool separates a room at 20 °C from outside air at 1 °C. The convection coefficients are 6 W/(m²·K) inside and 30 W/(m²·K) outside, and the wall area is 20 m². Find the heat loss Q̇ through the wall.

L1 = 200 mm, k1 = 0.035 W/(m·K)L2 = 50 mm, k2 = 0.04 W/(m·K)A = 20 m²hi = 6 W/(m²·K)ho = 30 W/(m²·K)Troom = 20 °CTout = 1 °C
Q̇ = W
6.Hard
Glass, k = 0.96150 mmExpanded polystyrene, k = 0.035150 mmroom 20 °Coutside -1 °CTs​ = ?Q̇

A wall of 150 mm glass and 150 mm expanded polystyrene separates a room at 20 °C from outside air at -1 °C. The convection coefficients are 8 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 10 m². Find the temperature Ts of the inside surface of the wall.

L1 = 150 mm, k1 = 0.96 W/(m·K)L2 = 150 mm, k2 = 0.035 W/(m·K)A = 10 m²hi = 8 W/(m²·K)ho = 25 W/(m²·K)Troom = 20 °CTout = -1 °C
Ts = °C

Answer key

  1. 1. Q̇ = 19440 W
  2. 2. q″ = 7 W/m²
  3. 3. Q̇ = 156.2 W
  4. 4. Q̇ = 813.2 W
  5. 5. Q̇ = 53.04 W
  6. 6. Ts = 19.43 °C

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