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A double-plane window consists of two ...

A double-plane window consists of two glass sheets each of area `1 m^(2)` and thickness `.01 m` separated by a `0.05 m` thick stagnant air space. In the steady state, the room glass interface and the glass outdoor interface are at constant temperature of `27^(@)C` and `0^(@)C` respectively. The rate of heat flow through the window pane is (Given , ` K_("glass") = 0.8 W m^(-1) K^(-1)`, `K_("air") = 0.08 W m^(-1) K^(-1)`)

Text Solution

Verified by Experts

The correct Answer is:
`41.6 W , 26.48^(@)C, 0.52^(@)C`
Heat flow for three sections will be same.
`therefore (27-theta)/(((L)/(KA))_(1st"pane")) = (theta_(1)-theta_(2))/(((L)/(KA))_(A.S.))= (theta_(2) - 0)/(((L)/(KA))_(2nd"pane"))`
`implies Q_(1) = 26.48^(@)C , Q_(2) = 0.52^(@)C`
Heat flow rate `(d theta)/(dt) = (27-theta)/(((L)/(KA))_(1st "pane")) = (27-26.48)/((0.01)/(0.8xx1)) = 41.6 "watt"`
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