Problem # 5 (10 marks) No need to solve (b). Please solve only (a) and (c). V,T The roof of a refrigerated truck compartment is of com- posite construction, consisting of a layer of foamed urethane insulation (250 mm, k₁ = 0.025 W/m-K) sandwiched between aluminum alloy panels (t₁ = 5 mm, k=280 W/m K). The length and width of the roof are L=10 m and W = 3.5 m, respectively, and the temper- ature of the inner surface is T, = -10°C. Consider con- ditions for which the truck is moving at a speed of V = 105 km/h, the air temperature is T = 23°C, and the solar irradiation is Gs = 650 W/m². Turbulent flow may be assumed over the entire length of the roof. Frank & Dave s à Desserts for Those Who Front Count Calories 12 (a) For equivalent values of the solar absorptivity and the emissivity of the outer surface (as = &= 0.5), estimate the average temperature To of the outer surface. What is the corresponding heat load imposed on the refrigeration system? (b) A special finish (as = 0.15, & = 0.8) may be applied to the outer surface. What effect would such an application have on the surface temperature and the heat load? (c) If, with as 8 = 0.5, the roof is not insulated (t₂ = 0), what are the corresponding values of the surface temperature and the heat load?