Consider the central receiver of Problem 12.117 to be a cylindrical shell of outer diameter D =

Question:

Consider the central receiver of Problem 12.117 to be a cylindrical shell of outer diameter D = 7 m and length L = 12 m. The outer surface is opaque and diffuse, with a spectral absorptivity of ?? = 0.9 for ? 3?m. The surface is exposed to quiescent ambient air for which T? = 300 K.

(a) Consider representative operating conditions for which solar irradiation at G s = 80,000 W/m2 is uniformly distributed over the receiver surface and the surface temperature is Ts = 800 K. Determine the rate at which energy is collected by the receiver and the corresponding collector efficiency.

(b) The surface temperature is affected by conditions internal to the receiver. For GS = 80.000 W/m2, compute and plot the rate of energy collection and the collector efficiency for 600