Energy is a basic unit for which the electricity utility (Eskom) charges. In the case of a lighting system:
Energy consumed (kilowatt-hour) = power (Watts) x time (hours)…
By using occupancy sensors and daylight harvesting, energy consumption can be reduced by the steady reduction of both power (Watts) and time (hours).
Owing to the availability of natural light, a light-dimming installation system can drastically reduce energy wastage, and depending on the application characteristics, daylight harvesting can save up to 70% on energy waste.
Light fixtures equipped with a dimming system have sensors that detect the amount of daylight in a room and, with their dimmable control gear; they automatically dim the luminaries up or down to maintain the prescribed lux levels. Two ways in which this is done, is by an “open loop” system, in which the sensor measures only the incoming daylight and calculates accordingly; or by a “closed loop” system, in which both daylight and artificial light are measured and calculated to maintain and set the appropriate lux level. The advantages of continuous dimming include the highest level of flexibility and user satisfaction due to consistent and accurate light levels. It also offers high energy savings.
Daylight harvesting controls can be effective in virtually any type of facility in which the lights operate much of the time and a significant quantity of daylight is provided by windows or skylights. With the increasing cost of electricity, environmental concerns and abundance of sunshine in South Africa, there should be a growing trend to move to daylight harvesting as a primary source of illumination. Daylight harvesting is an effective way to save energy without sacrificing the comfort of having sufficient lighting.
Voltex Lighting, together with their partner, Hubbell Automation, has a range of occupancy, daylight harvesting controls and devices to suit most applications.