by Prem Kumar, LC, MIES
In commercial lighting, the source of illumination is mostly light-emitting diode (LED) technology. Electrical and general contractors and consulting engineers for new construction and renovation are now faced with opportunities and challenges, as a luminaire may no longer be a ‘mere’ light fixture.
Smart lighting brings to a project a variety of sensors and technologies that enable a lighting infrastructure to become home minders, part of an entertainment assembly, security and fire-safety devices, and tools that help a business save money by optimizing luminaire use and providing information to HVAC and other building systems.
The smart lighting infrastructure creates a backbone, enabling the integration of many traditional, standalone building systems. The integration of smart lighting fixtures, sensing technologies, and communication capabilities has created the new paradigm of connected lighting systems (CLS). Through wired, wireless, and hybrid networks, the various lighting fixtures and sensors integrated into today’s facilities exchange information with each other and building management systems (BMS) to create seemingly endless possibilities.
Advantages and benefits
CLS comprises a class of lighting infrastructure that goes beyond illuminating spaces. By incorporating network interfaces, sensors, and distributed intelligence, CLS becomes a data collection platform, enabling a range of new capabilities as well as greater energy savings in buildings. Readers may recognize this concept by its other name—the Internet of Things (IoT). IoT merely expresses the idea that previously standalone smart devices are now internet-enabled and live on wired or wireless networks. Telephones, smart thermostats, kitchen appliances, security and home entertainment systems, door locks, televisions, and automobiles are now connected to the internet and are a part of the IoT. When devices are present on the internet or a private intranet (a network with limited or zero connectivity to the internet), the opportunity for them to interact and share information is enabled. CLS is becoming an important building block of the IoT.
This connectivity enables building professionals to add technologies and assets providing additional control of the living environment and gather data to help a BMS make better decisions. According to the research organization Gartner, IoT devices (or endpoints) associated with building automation and physical security will grow to 1.53 billion devices in 2020—up 20 percent from 2019, and 44 percent from 2018. One can only assume this rate of growth will continue to accelerate.
Another benefit of a CLS is doing away with running line voltage power to light fixtures by harnessing Power over Ethernet (PoE) technology. Reduced voltage and low amperage operating power—providing 13 to 100 W (depending on the specific PoE installation)—is supplied over the Ethernet cable itself, simplifying installation and conduit needs.
By evaluating data collected from CLS, a BMS can control HVAC and lighting loads and increase occupant comfort levels. Sensors can determine if a room is currently occupied, and the BMS can turn the lights on to a preset level and have the HVAC bring the room temperature to a set degree. Conversely, the lights can be dimmed or turned off and the temperature setting changed to reduce HVAC use when the space is vacant. Sensors have the ability to monitor the amount of daylight coming into a space and adjust the lighting on a per-fixture basis to decrease the output of luminaires near the window while adjusting the ones away from openings to maintain an even illumination level across the room.
Through sensor use and proper configuration, CLS can be a critical part of an automation system that can reduce energy costs. According to a 2017 report from energy.gov, energy use can be reduced by an average of 29 percent in commercial buildings when properly applied.
Occupant comfort and well-being
There are evidence light plays an important role in the well-being of occupants. It affects mood and alertness. The circadian rhythm (i.e. the human body clock controlling biological processes) is in tune with daylight changes—the color and intensity of daylight is constantly changing through the day and is a reminder for the body clock to follow these time-of-day cues. The color is measured in units called the correlated color temperature (CCT), with a warmer ‘white,’ such as sunrise or sunset, having a CCT value of 2700 to 3200 K. Daylight is considered a ‘cool’ CCT with a value of 5200 to 6000 K. Studies show cooler CCTs in the middle of the day keeps people alert and aware, improving productivity. Warmer CCTs at night create a sense of comfort and relaxation to help people unwind and get ready to sleep.