Question

The total area of the glass window pane is 0.5 m^2. Calculate how much heat is conducted per hour through the glass window pane if the thickness of the glass is 6mm, the temperature of the inside is 23°C end of the outside surface is 2°C. Thermal conductivity of glass is 1 W/m/K.

Answer 1

Explanation:

Given The total area of the glass window pane is 0.5 m^2. Calculate how much heat is conducted per hour through the glass window pane if the thickness of the glass is 6mm, the temperature of the inside is 23°C end of the outside surface is 2°C. Thermal conductivity of glass is 1 W/m/K.

• The quantity of heat Q passing through a slab of thickness a in t sec is
• Q = K A ( θ2 – θ1) t / a
• So total area of cross section A = 0.5 m^2
• Thickness of glass window pane a = 6 mm = 6 x 10^-3 m
• Temperature difference θ1 – θ2 = 23 -2 = 21 degree Celsius.
• Thermal conductivity K = 1 W/m/K
• Time t = 1 hr = 60 x 60 = 3600 secs
• Substituting we get
• Q = 1 x 0.5 x 21 x 3600 / 6 x 10^-3
• Q = 37800 / 6 x 10^-3
• Q = 6300 x 10^3
• Q = 63 x 10^5 Joules