Direction: An unplastered brickwork has a resistivity of 0.83 m degC/W. For a 230 mm thick brick wall, the inside and outside surface resistances are 0.123 and 0.1 m² degC/W respectively.
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The brick wall has an over all dimension of 6m × 3m with a 1m × 2m window assembly (U-value = 2.5 W/m² degC) and a 1m × 2.1m door assembly (U-value = 1.25 W/m² degC). The overall U-value of the wall (UO) (in W/m² degC) is ____
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- 0.5
- 0..25
- 5.25
- 2.3
Correct Option: D
Door area = 2 sq m
Window area = 2 sq m
Uvalue = [14 × (1/0.41) + (2 × 2.25) × (2 × 1.25)]/ 14 + 2 + 2 = 2.3
