A horizontal section of a vertical wall, made of three-core blocks of concrete, is shown in Fig. P8.3.1. The length, breadth and height of a block are 44 cm, 22 cm and 24 cm respectively. The two...

A horizontal section of a vertical wall, made of three-core blocks of concrete, is shown in Fig. P8.3.1. The length, breadth and height of a block are 44 cm, 22 cm and 24 cm respectively. The two faces of a block are 40 mm thick and the thickness of a web is 30 mm. The cores are filled with perlite insulation of thermal conductivity, 0.06 Wmí1 Kí1 . The thermal conductivity of concrete is 1.8 Wmí1 Kí1 . The outside and inside heat transfer coefficients are 26 Wmí2 Kí1 and 10 Wmí2 Kí1 respectively. Using the isothermal plane method, calculate (i) the average thermal resistance of the wall, and (ii) the average heat transfer coefficient.