Reconsider Prob. 3–25. Using EES (or other) software, plot the rate of heat transfer through the window as a function of the width of air space in the range of 2 mm to 20 mm, assuming pure conduction through the air. Discuss the results.

Data from Problem 25

Consider a 1.2-m-high and 2-m-wide double-pane window consisting of two 3-mm-thick layers of glass (k = 0.78 W/m·K) separated by a 12-mm-wide stagnant air space (k = 0.026 W/m·K). Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner surface for a day during which the room is maintained at 24°C while the temperature of the outdoors is 25°C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be h₁ = 10 W/m²·K and h₂ = 25 W/m²·K, and disregard any heat transfer by radiation.

Transcribed Image Text:

Glass 3 12 3 mm Frame