Sensing Savings

Automatic sensor controls are a very effective means for saving lighting energy. They let you use only as much lighting as you require. And you simply cannot save more lighting energy than by turning off unnecessary lights. Lighting regulated by a well-designed program of sensor controls is an efficient, cost-effective component of your building operating systems.

02/01/2004


Automatic sensor controls are a very effective means for saving lighting energy. They let you use only as much lighting as you require. And you simply cannot save more lighting energy than by turning off unnecessary lights. Lighting regulated by a well-designed program of sensor controls is an efficient, cost-effective component of your building operating systems.

The best time to make decisions about lighting controls in your facility is right now. First, ask who will be using the area. What will they be doing there? When will they be there, and for how long? The activities and lighting requirements vary in each area, and the lighting should operate according to the individual program of each room.

Sensor controls come in three types: infrared, ultrasonic and an ultrasonic/infrared hybrid usually called "dual technology." Upon detection of movement, the sensor energizes the lighting. When no movement is detected for a preset period of time, the sensor de-energizes the lighting. The sensor looks for motion in the space within a field that it creates out of ultrasonic sound or infrared light. Sensor types are made with a variety of field shapes and orientations for use within various shapes and sizes of rooms. Within the range of its field, an ultrasonic sensor will detect fine movements and even "see" over partitions. Ultrasonic sensors work very well in restrooms, conference rooms and open-plan workstations. An infrared sensor detects movement across the bands of light that it emits. Consequently, it only detects large movements within its line of sight. Subtle movements, such as typing at your desk, may not be detected by an infrared sensor. Infrared sensors work very well in corridors and large circulation spaces. Dual technology sensors combine the benefits of both types.

Automatic lighting controls are mandated in many parts of the country. Western states such as California and Washington provide specific requirements for the type and operation of lighting controls within their energy codes. Other states will soon pass such regulations. Problems arise when they are applied without considering the impact on the people working in the space. Avoiding these problems is the duty of the system designer and the installer.

"False offs" produced by sensors that are mismatched to the application, or improperly adjusted, create problems for users and ill will for any application of sensor controls. Office workers who cannot get through their day without waving their hands in the air to keep their lights lit will complain loudly and influence future decisions about sensors. The system designer and the installing contractor must deliver a proper system. Control function and sensitivity patterns much be correctly matched to the spaces. After installation, the control systems must be "tuned." This should happen after about 60 days of use. Problems and complaints should be addressed by changing out mismatched sensor technologies and adjusting sensor sensitivity and auto-off time delays. Tuning activities should be written into the project close-out responsibilities of the installing contractor.

Automatic sensor controls, when correctly applied and adjusted, can produce tremendous savings for the building owner without leaving the building's occupants "in the dark."



Sensor control tips

Select the best sensor control type for the environment

Consider the impact the control has on the people working in the space

Designate a tuning period



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