Consider a double-paned window consisting of two panes of glass, each with a thi

Question

Consider a double-paned window consisting of two panes of glass, each with a thickness of 0.500cmand an area of 0.760m2 , separated by a layer of air with a thickness of 1.55cm . The temperature on one side of the window is 0.00 ?C; the temperature on the other side is 25.0?C. In addition, note that the thermal conductivity of glass is roughly 36 times greater than that of air.

A. Approximate the heat transfer through this window by ignoring the glass. That is, calculate the heat flow per second through 1.55cm of air with a temperature difference of 25.0?C . (The exact result for the complete window is 28.2J/s .)

B. Use the approximate heat flow found in part A to find an approximate temperature difference across each pane of glass. (The exact result is 0.221?C .)

Explanation / Answer

Qdot = kappa * A *delta(T)/D
For air, kappa = 0.025 W / m C, so

Qdot = 0.025 J/s / (m C) * 0.760m^2 * 25.0C/(0.0155m) = 30.645 J/s


(b) That same heat flow is through a pane, so

30.645 J/s = 36*0.025W/(m C) * 0.760m^2 * Delta(T) / (0.005 m) =>

Delta(T) = 0.2240 C

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.