The steady state temperature distribution in a 0.3 m thick plane wall is T-600 + 2500x - 12,000x² where T'is in °C and x is in metre measured from one surface of the wall. One-dimensional steady state heat conduction occurs in the wall along the x-direction. The thermal conductivity of the material of the wall is 23.5 W/m "C. (a) What are the surface temperatures and the average temperature of the wall? (b) Calculate the maximum temperature in the wall and its location. (c) Calculate the heat fluxes at the surfaces.

An industrial cold room has four 200 mm thick walls made of concrete. The walls are insulated on the outside with a layer of foam 60 mm thick. Cladding with a thickness of 15 mm protects the foam on the outside from the elements. The composite wall surface temperatures are –3 °C on the inside and 18 °C on the outside of the room respectively. The thermal conductivities of concrete, foam and cladding are 0.75, 0.35 and 0.5 W/m K respectively. a) Assuming perfect thermal contact between the layers of the composite walls, draw the typical temperature distribution across the layers and determine the heat energy gained per hour through all 4 walls of the room with a total surface area of 20 m2 . What does this heat energy represent in terms of the refrigeration system of the cold room?

If the thickness of a plane wall is doubled from x to 2x while maintaining the same temperatures on each side of the wall, the conductive heat transfer rate (q) 2x increases decreases stays the same none of the above