Question

The front wall of an old jewellery store has an area of 20 m2 and is...

The front wall of an old jewellery store has an area of 20 m2 and is constructed of 200 mm of concrete and 250 mm of polystyrene. The wall contains a large window of 5 m x 2 m of 50 mm thick glass. The inside temperature is 21°C and the outside temperature is 3°C. Calculate: (i) the rate of flow of heat through the glass, and (ii) the total rate of heat transfer through the wall and window. Note: Average thermal conductivities are: • Concrete 0.600 W m-1 K-1 • Polystyrene 0.030 W m-1 K-1 • Glass 0.800 W m-1 K

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