Solar water heaters are often used to provide hot camp showers. A typical design consists of a bag about 0.5 m 0.5 m x 0.1 m in size, that is filled with water. The top surface of the bag is transparent, while the bottom surface is black to absorb the solar radiation. On a particular day, the bag is placed on a horizontal surface to heat. The solar radiation produces a heat flux of 700 W m, which all passes through the water and is absorbed by the bottom black panel. No heat is lost through the base or sides of the bag. No radiation from the sun is absorbed by the water directly. a) What mechanism governs the heat transfer from the hot black surface of the bag to the water? b) Consider an energy balance on the hot black surface. If the system is at a pseudo steady state, what is the heat flux from the hot surface to the water? c) Estimate the temperature difference between the base of the bag and the water. d) Why is it better to have a transparent top panel and black bottom panel, as opposed to a black top panel? Solar camp shower bag sun asun (radiation) black 0.5 m water 0.1 m base qwater solid surface 9=0 Heat fluxes to and from the surface of the bag are indicated by red arrows. Drawing is not to scale