Question

A heat flux meter attached to the inner surface of a 3-cm-thick refrigerator door indicates a heat flux of 25 W/m² through the door. Also, the temperatures of the inner and the outer surfaces of the door are measured to be 7°C and 15°C, respectively. Determine the average thermal conductivity of the refrigerator door. Answer: 0.0938 W/m. C

Answer 1

0.0938 W/m.°C

Step-by-step explanation:

The heat is flowing by the refrigerator door by conduction, and can be calculated by the equation:

q = k*ΔT/L

Where q is the heat flux (25 W/m²), k is the thermal conductivity of the refrigerator, ΔT is the variation of the temperature (inner - outer), and L is the thickness of the door (0.03 m).

25 = k*(15-7)/0.03

8k = 0.75

k = 0.0938 W/m.°C