Entering a dark room, a dark parking lot, or a dark corridor makes many people anxious. Similarly, wasting energy when it is not in use is a pet peeve for many and annoys them. So what is the solution that ensures that both the parties are satisfied? Lighting control panels now come with an occupancy sensor to solve this problem. Let us learn more about them.
What Is An Occupancy Sensor?
Occupancy sensors are also known as motion or personnel sensors. These sensors automatically turn the lights on when someone enters the room and switches it off when they leave. Occupancy sensors are the simplest way to save energy when it comes to industrial applications.
A sensor reacts to variables like motion or heat to monitor the on and off mechanism. According to the Energy Department, the electricity consumption of an industrial building is around 38 per cent. Thus, ensuring a better system of managing electricity is a step towards a greener environment.
What Are The Benefits Of Sensors:
A sensor provides various benefits when it comes to commercial use. Some of the most common advantages of using sensors are:-
· Sensors ensure the fulfilment of mandatory requirements for renovation and building construction.
· They contribute to scores in several LEED credit categories.
· Sensors increase convenience as manual switching of the lights is not a requirement anymore.
· They enhance the security of isolated areas by automation of the light system.
· Sensors can reduce the consumption rate by 35-45 per cent if brought into correct use.
The Various Types Of Occupancy Sensors
There are generally three types of sensors and one combination sensor.
· Microwave Motion Sensor: these sensors detect motion through the principle of Doppler radar, and are similar to a radar speed gun. A continuous wave of microwave radiation is emitted, and phase shifts in the reflected microwaves due to motion of an object toward (or away from) the receiver result in a heterodyne signal at a low audio frequency.
· Passive infrared (PIR) sensors:- The PIR sensor is an innovation that detects the warmth of an individual. In these sensors, a change in levels of infrared is the trigger point. The mechanism of the PIR sensor uses a multi-faceted lens that defines the coverage area like a fan shape of discrete zones. The sensor lens is also responsible for determining the size of the motion that it will detect. The lens of the sensor detects movement when an individual passes these zones. This movement pattern makes the lens more sensitive to lateral motion. The gap between the zones increases with distance and, the sensitivity of the sensor decreases. PIR sensors work efficiently up to 40 feet in case of the full-body moment while works up to 15 feet for discrete hand movements.
· Ultrasonic sensors(US): Unlike the PIR sensors that detect temperature, an ultrasonic sensor emits inaudible sound waves to continue to check for a change in the frequency of the reflected waves. Ultrasonic sensors set up a sound wave to observe changes in both frequency and amplitude due to movements. The frequency of the ultrasonic waves sent by the sensor is above the hearing frequency that the ear can detect. This difference in frequencies also helps avoid problems that hearing aids might face due to the same frequency. An ultrasonic sensor does not depend on the direct line of sight to sense someone. Thus, making it the perfect fit for environments with stalls and cubicles. It is capable of detecting any minor movement up to a distance of 25 feet. US sensors are sensitive and efficient.
· Dual Technology: Sensors that use dual technology utilize two methods for detection. These two method use increases reliability where better efficiency detection is desirable. Example: Individuals in a classroom who remain seated in the same place for a longer time. Generally, manufacturers combine both US and PIR technologies. In such cases, the lights trigger only when a presence detection happens by both technologies. Though lights turn on only when both technologies detect a presence, only one technology is needed to keep the lights on. There is another sensor combination it combines acoustic detection and PIR technology. This combined technology is known as passive DT. In this, there is no waves emission into space. In this, the microphone filters out the characteristics of noise that resembles occupant activity.
Mounting configurations for occupancy sensors:
There are two basic configurations when it comes to mounting the sensors. They are:-
· Ceiling installed sensors:- These sensors have an autonomous controller and energy supply. Their installation takes place on high walls and corners.
· Wallbox sensors:- These sensors are designed as retrofit replacements for wall switches.
Both types of mounting styles are available in ultrasonic sensors and PIR sensors.
How This Technology Saves Energy
Sensors are devices that respond to the absence and presence of people in their field. They are also known as switching devices due to the role they play in an industrial building. But what is the mechanism behind it, and how it saves energy is the next big question?
A sensor system comprises a motion detector a, controllable switch and, an automated control unit. The motion detector detects the movement and triggers a signal( either on or off). The transfer of the sign to the control unit takes place. It handles the power supply to the lights. The control units gather data from the sensors and evaluate the occupancy state of the space.
The control unit has the option to calibrate the sensitivity of motion sensors. One also has the authority to input a timing after which the sensor turns off the light when not been used.
In occupancy sensor arrangements, the movement detector and controller are in a single package. The power supply and relay are integral unit systems, seldom known as a switch pack. In a wall box sensor, elements are all in one condensed unit, meant to fit into a current switch box.
What Type of Light Source Should We Use With Sensors?
Occupancy sensors’ integral role is to switch on instantly on detecting a presence so, they need energy sources that have short restrike time and are quick to start. Restrike time is the time the light source takes to deliver the complete output after it turns on.
Therefore, occupancy sensors work excellently with quick-starting LED, incandescent, and fluorescent sources. However, the sensors do not operate well with metal halide and other discharge lamps because of their longer restrike times.
Recent NewsWhere are Occupancy Sensors Required03th September 2021What is the Difference Between Occupancy and Vacancy Sensor27th August 2021How to Program Occupancy Sensor? 14th August 2021