(a) (b) (c) What is daylight factor? Explain how daylight factor can be used to determine the daylight illuminance at a point in an interior space? Can we evaluate the daylight quality of a space based on daylight factor only? Why? (5 marks) The CIBSE Lighting Guide and British Standards recommend the following formula to calculate the average daylight factor for a side-lit room under a standard overcast sky with a lean glazing as follows: TAWO A(1 - R) DFav = % Please explain each of the parameters used in the formula. Which of these parameters are related to the amount of daylight available at the window? (5 marks) Consider two small rooms in a same building, one on the 40th floor and the other on the ground floor. This building is facing a group of other buildings with the same height in a row at a distance 30 m apart (see Figure Q3). The window plane can be assumed to be at the outer wall surface of the building. Room dimensions: width (along window wall) = 2.5 m; depth (perpendicular to window wall) = 3 m; floor to ceiling height = 3 m; floor to floor height = 3.2 m. Window in one wall only: window width = 2 m; window height = 1.3 m; Sill height = 1.2 m; glazing transmittance = 0.7 Room surface reflectance: ceiling = 0.8; walls = 0.5; floor = 0.2; window = 0.1 Please calculate the average daylight factor for these two rooms. (d) In recent years, we use climate-based daylight modeling (CBDM) for characterizing the quality and quantity of daylight in a space. Please list and define the various metrics derived from CBDM. (5 marks) 40th floor 1st floor (10 marks) Opposite row of residential 30 m Figure Q3 Sketch of building and obstruction (not to scale)