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
Mineral wool, k = 0.04200 mm21 °C2 °Cq″ = ?

A wall of mineral wool is 200 mm thick and has an area of 4 m². Its faces are held at 21 °C and 2 °C. Find the heat flux q″ through the wall.

k = 0.04 W/(m·K)L = 200 mmA = 4 m²T1 = 21 °CT2 = 2 °C
q″ = W/m²
2.Easy
Concrete, k = 1.410 mm19 °C10 °CQ̇ = ?

A wall of concrete is 10 mm thick and has an area of 8 m². Its faces are held at 19 °C and 10 °C. Find the rate of heat conduction Q̇ through the wall.

k = 1.4 W/(m·K)L = 10 mmA = 8 m²T1 = 19 °CT2 = 10 °C
Q̇ = W
3.Medium
Concrete, k = 1.450 mmExpanded polystyrene, k = 0.03550 mm24 °C-14 °CTi​ = ?Q̇

A wall is made of 50 mm of concrete and 50 mm of expanded polystyrene, with an area of 20 m². The outer faces are at 24 °C and -14 °C. Find the temperature Ti at the interface between the two layers.

L1 = 50 mm, k1 = 1.4 W/(m·K)L2 = 50 mm, k2 = 0.035 W/(m·K)A = 20 m²T1 = 24 °CT3 = -14 °C
Ti = °C
4.Medium
Glass, k = 0.96100 mmConcrete, k = 1.475 mm20 °C-14 °CQ̇ = ?

A wall is made of 100 mm of glass and 75 mm of concrete, with an area of 8 m². The outer faces are at 20 °C and -14 °C. Find the heat flow Q̇ through the wall.

L1 = 100 mm, k1 = 0.96 W/(m·K)L2 = 75 mm, k2 = 1.4 W/(m·K)A = 8 m²T1 = 20 °CT3 = -14 °C
Q̇ = W
5.Hard
Brick, k = 0.7250 mmWood, k = 0.1725 mmroom 22 °Coutside -7 °CQ̇ = ?

A wall of 50 mm brick and 25 mm wood separates a room at 22 °C from outside air at -7 °C. The convection coefficients are 6 W/(m²·K) inside and 25 W/(m²·K) outside, and the wall area is 10 m². Find the heat loss Q̇ through the wall.

L1 = 50 mm, k1 = 0.72 W/(m·K)L2 = 25 mm, k2 = 0.17 W/(m·K)A = 10 m²hi = 6 W/(m²·K)ho = 25 W/(m²·K)Troom = 22 °CTout = -7 °C
Q̇ = W
6.Hard
Expanded polystyrene, k = 0.035250 mmBrick, k = 0.72150 mmroom 21 °Coutside 5 °CTs​ = ?Q̇

A wall of 250 mm expanded polystyrene and 150 mm brick separates a room at 21 °C from outside air at 5 °C. The convection coefficients are 8 W/(m²·K) inside and 20 W/(m²·K) outside, and the wall area is 12 m². Find the temperature Ts of the inside surface of the wall.

L1 = 250 mm, k1 = 0.035 W/(m·K)L2 = 150 mm, k2 = 0.72 W/(m·K)A = 12 m²hi = 8 W/(m²·K)ho = 20 W/(m²·K)Troom = 21 °CTout = 5 °C
Ts = °C

Answer key

  1. 1. q″ = 3.8 W/m²
  2. 2. Q̇ = 10080 W
  3. 3. Ti = 23.07 °C
  4. 4. Q̇ = 1724 W
  5. 5. Q̇ = 685.3 W
  6. 6. Ts = 20.73 °C

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