Figure 41 Daylight levels for 2nd floor

Figure 40 Daylight levels for 2nd floor

Thorn Line XS luminaires were chosen which contain two T16 fluorescent lamps each

producing 2600 lumens. Total power consumption for each luminaire is 63W. The surface

reflectivity for floor, walls, and ceiling are 0.5, 0.2 and 0.5 respectively. The mounting height was calculated to be 2m. Using RI = for the room index gives RI = 5.57, 6.18 and 6.62 for ground 1st and 2nd floor respectively. W was different for each floor as the area in need of lighting was different. The utilization factor (UF) value was taken from the Line XS luminaire table UF = 0.74. A surplus of 55 lux for the ground floor, 230 lux for the first floor and 290 lux for the second floor were required to cover the lighting needs not satisfied by daylight alone. Using the formula n = and the appropriate area for A (as shown in the figures below) the lamps number was found to be 28 for ground floor, 130 for first floor and 180 for second floor. Total electrical consumption = (14+65+90) 63 = 10647W. Annual consumption (working hours) = 10647 11 365 = 42748kWh. The total annual electricity consumption was then summed up to give 42748 + 25175 = 67923kWh