Question

Consider a 1.5 m high and 2 m wide triple pane window. The thickness of each glass layer (k = 0.80 W/m-K) is 0.5 cm, and the thickness of each air space (k = 0.025 W/m-K) between is 1 cm. If the inner and outer surface temperatures of the window are ${10}^{\circ }C$ and $0^{\circ }C$, respectively, the rate of heat loss through the window is

• A. 37 W
• B. 75 W
• C. 12 W
• D. 46 W

Answer 1

The correct option is A 37 W



Thermal Circuit




$Heattransferrate\left(Q\right)=\frac{(10-0)}{3\times \frac{0.005}{0.8A}+2\times \frac{0.01}{0.025A}}$

$=\frac{10\times A}{0.81875}$

$=12.21A$

$=12.21\times 2\times 1.5$

$Q=36.64W$