A thin sheet of glass is used on the roof of a greenhouse

Chapter , Problem 12.12

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A thin sheet of glass is used on the roof of a greenhouse and is irradiated as shown. The irradiation comprises the total solar flux GS, the flux Gatm due to atmospheric emission (sky radiation), and the flux Gi due to emission from interior surfaces. The fluxes Gatm and Gi are concentrated in the far IR region ( 8 m). The glass may also exchange energy by convection with the outside and inside atmospheres. The glass may be assumed to be totally transparent for 1 m ( 1.0 for 1 m) and opaque, with 1.0 for 1 m. (a) Assuming steady-state conditions, with all radiative fluxes uniformly distributed over the surfaces and the glass characterized by a uniform temperature Tg, write an appropriate energy balance for a unit area of the glass. (b) For Tg 27 C, hi 10 W/m2 K, GS 1100 W/m2 , T,o 24 C, ho 55 W/m2 K, Gatm 250 W/m2 , and Gi 440 W/m2 , calculate the temperature of the greenhouse ambient air, T,i . 12.121 A sola