energy saving controls 100
Percentage Illumination Required
To illustrate the potential for energy saving using daylight linked dimming, we can model a typical 60m² classroom and consider the penetration of natural light as a percentage of the required illuminance across the space. If we assume 3 rows of lighting, each row comprising of 3 zones typically window row, centre row and inner row, we can assess the benefit from investing in dimming capability in each zone.
Inner Row
90
Centre Row
80 70
Window Row
60 50 40 30 20 10 0 J
F
M
A
M
J
J
A
S
O
N
D
Months
The graph opposite illustrates the amount of illumination required at each row of luminaires on a monthly basis. The table below details the energy use and savings that can be made by investing in this technology.
Installed load (KW)
running hours
annual energy use (KWh)
Annual energy saving (KWh)
No Controls
0.558
1800
1004
0
Detection
0.558
1200
670
334
Detection/Window Dimming
0.558
1200
486
518
Detection/All Dimming
0.558
1200
323
681
based on a classroom with 9, 4 X 14W (62 circuit watts recessed luminaires)