A 3-m² black surface at 140?C is losing heat to the surrounding air at 35°C by convection with a heat transfer coefficient of 16 W/m²•C, and by radiation to the surrounding surfaces at 15°C. The total rate of heat loss from the surface is
(a) 5105 W
(b) 2940 W
(c) 3779 W
(d) 8819 W
(e) 5040 W
(d) 8819 W
Solutions can be verified by copying-and-pasting the following lines on a blank EES screen.
sigma=5.67E-8 [W/m^2-K^4]
eps=1
A=3 [m^2]
h_conv=16 [W/m^2-C]
Ts=140 [C]
Tf=35 [C]
Tsurr=15 [C]
Q_conv=h_conv*A*(Ts-Tf)
Q_rad=eps*sigma*A*((Ts+273)^4-(Tsurr+273)^4)
Q_total=Q_conv+Q_rad
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