A south facing wall of a building is 5 m high and 7 m wide. The wall absorbs the incident solar energy at a rate of 500 W/m^2. It is assumed that about 200 W/m^2 of the absorbed energy in conducted through the wall into the interior of the wall, and the remaining energy is dissipated by free convection into the surrounding quiescent atmospheric air at 25 ºC. Calculate the temperature of the outside surface of the wall.