The wall of a building measures 8 m horizontally by 3 m vertically, and consists of 250- mm-thick concrete. on the inside it is covered with 140-mm-thick extruded polystyrene insulation. the wall has a 1.4 m × 1.0 m door of 12-mm-thick plywood with no insulation. outside and inside air temperatures are -5°c and 18°c, respectively. the corresponding convection heat transfer coefficients are 38 w m2 k-1 and 7 m-2k-1. calculate the rate of 1151 (a) heat transfer through the wall