The overall heat transfer coefficient (the U–value) of a wall under winter design conditio...

The overall heat transfer coefficient (the U–value) of a wall under winter design conditions is U = 2.25 W/m2·K. Now a laver of lO0-mm face brick is added to the outside. leaving a 20-mm air space between the wall and the bricks. Determine the new [7-value of the wall. Also, determine the rate of heat transfer through a 3-m-high, 7-m·long section of the wall after modification when the indoor and outdoor temperatures are 22°C and −25°C, respectively.

FIGURE P3–154