Chapter 12, Problem 12.141P

A solar panel mounted on a spacecraft has an area of 1 m2 and a solar-to-electrical power conversion efficiency of 12%. The side of the panel with the photo- voltaic array has an emissivity of 0.8 and a solar absorptivity of 0.8. The back side of the panel has an emissivity of 0.7. The array is oriented normal to solar irradiation of ${\text{1500 W/m}}^2$ .

(a) Determine the steady-state temperature of the panel and the electrical power (W) produced for the prescribed conditions.

(b) If the panel were a thin plate without the solar cells, but with the same radiative properties, determine the temperature of the plate for the prescribed conditions. Compare this result with that from part (a). Are they the same or different? Explain why.

(c) Determine the temperature of the solar panel 1500 s after the spacecraft is eclipsed by a planet. The thermal capacity of the panel per unit area is ${\text{000 j/m}}^2\cdot K$ .