A Thin layer of water is placed in a pan 1 m in diameter in the desert. The upper surface is exposed to 300 K air and the convection heat transfer coefficient between the upper surface of the water and the air is estimated to be 10 W/(m2 K). The effective sky temperature depends on atmospheric conditions and is often assumed to be 0 K for a clear night and 200 K for a cloudy night. Calculate the equilibrium temperature of the water on a clear night and a cloudy night.GIVENA thin layer of water in a circular pan in the desertPan diameter (D) = 1 mAir temperature (T??) = 300 KConvective heat transfer coefficient (hc) = 10 W/(m2 K)Effective sky temperature (T2) = 0 K for a clear night, 200 K for a cloudy nightASSUMPTIONSSteady state conditionsThe effect of the sides of the pan is negligibleHeat transfer to the ground is negligibleEdge losses are negligibleNeglect losses due toevaporation

Transcribed Image Text:

Sky:T2 =0Kor 200 K Alr: T- 300 K Water, T1 =? D= 1m