Complete the following sentences (showing your calculation):   The R- value for a 50 mm wood fiber insulation board (k= 0.044 W/m.K)= ……….................................................................................................... The U- value for a 120 mm clay roofing tile (k= 0.75 W/m.K)= ..................  The light solar gain ratio for a window with the following characteristics (U= 1.11 W/m2.K, SHGC = 86%, VT= 90%)…………………………………………………………. In a room (8*6*3.5) if the total heat losses is 1000 Watt and the percentage of ceiling losses from total was 20% , if we treat just the ceiling such that we reduce her losses by the half what will be the new total losses for the room …………………………………………………….........................................................…..

Calculate the heat loss from a double-pane glass window consisting of two pieces of glass, each having a thickness of 10 mm with a thermal conductivity of k = 1.3 W/m.K . The two glass panes are separated by an air gap of 7 mm. Assume thermal conductivity of air to be k = 0.022 W/m.K .

On a hot summer day, the flat roof of a tall building reaches 50° C in temperature. The area of the roof is 400m2. Estimate the heat radiated from this roof to the sky in the evening when the temperature of the surrounding air or sky is at 20° C. The temperature of the roof decreases as it cools down. Estimate the rate of energy radiated from the roof, assuming roof temperatures of 50, 40, 30, and 25° C. Assume ε = 0 9 . for the roof.