During a winter day, the window of a patio door with a height of 1.8 m and width of 1.0 m shows a frost line near its base. The room wall and air temperatures are 15°C.

(a) Explain why the window would show a frost layer at the base rather than at the top.

(b) Estimate the heat loss through the window due to free convection and radiation. Assume the window has a uniform temperature of O°C and the emissivity of the glass surface is 0.94. If the room has electric baseboard heating estimate the corresponding daily cost of the window heat loss for a utility rate of 0.08 $/kW ∙ h.

Transcribed Image Text:

L Window, 1.8 mx 1.0 m