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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
Concrete, k = 1.4100 mm23 °C-8 °Cq″ = ?

A wall of concrete is 100 mm thick and has an area of 6 m². Its faces are held at 23 °C and -8 °C. Find the heat flux q″ through the wall.

k = 1.4 W/(m·K)L = 100 mmA = 6 m²T1 = 23 °CT2 = -8 °C
q″ = W/m²
2.Easy
Mineral wool, k = 0.04100 mm24 °C-7 °CQ̇ = ?

A wall of mineral wool is 100 mm thick and has an area of 6 m². Its faces are held at 24 °C and -7 °C. Find the rate of heat conduction Q̇ through the wall.

k = 0.04 W/(m·K)L = 100 mmA = 6 m²T1 = 24 °CT2 = -7 °C
Q̇ = W
3.Medium
Expanded polystyrene, k = 0.035250 mmGlass, k = 0.9625 mm25 °C-5 °CQ̇ = ?

A wall is made of 250 mm of expanded polystyrene and 25 mm of glass, with an area of 6 m². The outer faces are at 25 °C and -5 °C. Find the heat flow Q̇ through the wall.

L1 = 250 mm, k1 = 0.035 W/(m·K)L2 = 25 mm, k2 = 0.96 W/(m·K)A = 6 m²T1 = 25 °CT3 = -5 °C
Q̇ = W
4.Medium
Brick, k = 0.72150 mmWood, k = 0.17150 mm17 °C-14 °CTi​ = ?Q̇

A wall is made of 150 mm of brick and 150 mm of wood, with an area of 20 m². The outer faces are at 17 °C and -14 °C. Find the temperature Ti at the interface between the two layers.

L1 = 150 mm, k1 = 0.72 W/(m·K)L2 = 150 mm, k2 = 0.17 W/(m·K)A = 20 m²T1 = 17 °CT3 = -14 °C
Ti = °C
5.Hard
Concrete, k = 1.450 mmMineral wool, k = 0.04150 mmroom 20 °Coutside 2 °CQ̇

A wall of 50 mm concrete and 150 mm mineral wool separates a room at 20 °C from outside air at 2 °C. The convection coefficients are 8 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 8 m². Find the overall heat transfer coefficient U of the wall.

L1 = 50 mm, k1 = 1.4 W/(m·K)L2 = 150 mm, k2 = 0.04 W/(m·K)A = 8 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 20 °CTout = 2 °C
U = W/(m²·K)
6.Hard
Mineral wool, k = 0.0450 mmGlass, k = 0.96100 mmroom 20 °Coutside 1 °CTs​ = ?Q̇

A wall of 50 mm mineral wool and 100 mm glass separates a room at 20 °C from outside air at 1 °C. The convection coefficients are 10 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 20 m². Find the temperature Ts of the inside surface of the wall.

L1 = 50 mm, k1 = 0.04 W/(m·K)L2 = 100 mm, k2 = 0.96 W/(m·K)A = 20 m²hi = 10 W/(m²·K)ho = 25 W/(m²·K)Troom = 20 °CTout = 1 °C
Ts = °C

Answer key

  1. 1. q″ = 434 W/m²
  2. 2. Q̇ = 74.4 W
  3. 3. Q̇ = 25.11 W
  4. 4. Ti = 11.08 °C
  5. 5. U = 0.2525 W/(m²·K)
  6. 6. Ts = 18.73 °C

Full step-by-step solutions: practise this topic on examproblems.com.