The roof of a refrigerated truck compartment is of composite construction, consisting of a layer of foamed urethane insulation (t2 = 50 mm, ki = 0.026 W/m · K) sandwiched between aluminum alloy panels (tz = 5 mm, kp = 180 W/m · K). The length and width of the roof are L = 12 m and W = 3.5 m, respectively, and the temperature of the inner surface is Ts, i = -10°C. Consider conditions for which the truck is moving at a speed of V = 110 km/h, the air temperature is To = 30°C, and the solar irradiation is Gs = 900 W/m². Turbulent flow may be assumed over the entire length of the roof. TO -E, as Frank & Dave's Frozen Desserts for Those Who Don't Count Calories VT (a) For equivalent values of the solar absorptivity and the emissivity of the outer surface (ag = e = 0.6), estimate the average temperature Ts, o of the outer surface. What is the corresponding heat load imposed on the refrigeration system? (b) A special finish (as = 0.2, 8 = 0.8) may be applied to the outer surface. What effect would such an application have on the surface temperature and the heat load?