A 1.8 m x 1.5 m composite wall separates a furnace from the rest of the room in which it is located. The wall is made of 3 layers of different materials. Facing the furnace is a 10-cm thick layer of stone mix concrete. The side of the wall facing the room (cooler side) is made of 8-cm thick common brick. In between the concrete and brick layers is a 2.5-cm thick cellular glass insulation (use 420 K as the reference temperature for material properties of insulation). The gas inside the furnace (hot side) is at a temperature of 275 oC with a corresponding convection heat transfer coefficient of 100 W/m2.K. The room air is at a uniform temperature of 22 oC with a corresponding convection heat transfer coefficient of 35 W/m2.K. Neglect all radiative heat transfer effects.
Draw a thermal circuit and calculate all the surface and interface temperatures along with the heat transfer rate from the furnace into the room.