Power over Ethernet brings a wealth of efficiencies to smart building initiatives.
by Giovanni Frezza, Group Product Manager, Molex
Power over Ethernet (PoE) lighting and automation systems help make highly innovative building concepts possible. These distributed networks deliver electrical power and transmit communications signals over standard low-voltage category cabling to various endpoints, including LED lighting, HVAC controls, cameras, and other networked devices in a new or existing commercial building, and are designed to promote energy efficiency and boost productivity. Currently, operational technology (OT) is rapidly adopting the PoE infrastructure that has been widely used by information technology (IT) infrastructure for commercial buildings. Pilot installations and significant retrofit projects are bringing PoE to commercial spaces around the world.
Commercial builders, developers, architects, and engineering firms are crucial collaborators and important proponents leading the charge to bring powerful PoE networks into widespread use. PoE infrastructure can also be seen as a synergistic asset for enabling Internet of Things (IoT) and smart building initiatives — and one that can add significant value for building developers, owners, and occupants.
In recent years, advanced technologies have propelled the adoption of network-connected lighting systems and led to the development of more efficient standards for building automation. Unlike traditional networks that require a dual-layer infrastructure, PoE platforms transport both power and data on the same low-voltage cable infrastructure. Although most installed control systems are based on proprietary solutions, leading technology suppliers and the commercial building industry are trending toward use of open standards to simplify the installation, configuration, and commissioning of new networks.
The technologies used in PoE networks are well defined by IEEE802.3 standards, which specify the physical and data link layers for wired Ethernet networks, power sourcing equipment, and devices using two-pair or four-pair connections to transmit power. The original PoE standard (IEEE802.3af-2003) was based on 15.4W per switch port of power, but has since increased to 30W for PoE+ (IEEE802.3at), which uses a two-pair power transfer format. More recent standards use a four-pair power transfer format. Cisco’s Universal Power Over Internet (UPOE) can support 60W per switch port and the HDBaseT Alliance’s Power over HDBaseT (POH) can support more than 95W per switch port.
Utilizing all four twisted pairs, UPOE technology can deliver more power with improved efficiency and reduced channel losses than PoE+. Using UPOE, a PoE node can receive up to 51W of power, enabling the optimization of low-voltage cable infrastructure by daisy chaining multiple devices on a single UPOE port. This reduces the number of ports and the amount of cabling required by a system. The new IEEE standards improve efficiency and allow a wider range of device functions and support, and can also be performed on low-voltage Class D (Cat5e) cable using the same infrastructure that the IT industry has deployed for over a decade. A distributed network enables building or enterprise-wide precision control, integration with other building automation systems, and improved data that can be used to inform workforce and building usage decisions.
Standards and specifications establish protocols for power delivery and communications links for exchanging data, but they don’t tell the entire story about the value of PoE networks in building control systems. The proliferation of smart technologies set the stage, with architects, electricians, and installers on the frontline using PoE LED fixtures to transform buildings.
Legacy lighting fixtures can readily be retrofitted with LEDs and sensors capable of local smart control. In older buildings, these lighting systems utilize AC power that has been converted to low-voltage power. Retrofitting existing fluorescent and compact fluorescent lighting fixtures with LEDs was a first step for many and the resulting penetration in commercial building markets has made LEDs surprisingly cost-competitive with other lighting technologies. Outstanding lighting output per watt of power is the primary driver of LED adoption in commercial buildings, which greatly improves on older lighting technologies.
Advanced LED technologies are becoming increasingly versatile, efficient, secure, and capable of supporting available wattages in PoE lighting systems. The ability to migrate lighting controls to IP-based infrastructure makes lighting a service and an IoT building asset that can be controlled synergistically along with other building functions. Greater integration results in better control, and has led to drastic energy savings, increased occupant comfort, and improved productivity performance. It also allows more meaningful data to be collected by the distributed sensor system as part of the lighting network infrastructure.
Optimized to deliver low-voltage power and reliable communication, a PoE gateway distributes power and connects luminaires, sensor nodes, wall dimmers, and other local devices and controls to the IP network and control manager, and each gateway is connected to a switch port with a Cat5e cable. The IP nodes are responsible for power and data distribution to local devices. Lights, sensors, motorized shades, dispensers, motors, and other devices become digital objects that can be configured, grouped together, and controlled via software. Smart horizontal cable design is critical to optimizing the low-voltage power distribution required for efficient and cost-effective implementation.
A well-implemented PoE control system delivers uninterrupted power service, greater network resiliency, and reduced operating expenses. New networks and devices are also faster to deploy because PoE networks don’t require power outlets at each device endpoint. Commercial buildings are prime candidates for PoE lighting and automation systems, which can be designed as part of a building’s infrastructure or retrofitted into an existing structure. These designs need to optimize power and data distribution in order to minimize the number of PoE ports required. If the power requirement for a group of devices is below 50W, for example, a single PoE gateway can power and control multiple drivers in a daisy-chain configuration. System software tools should provide support during the complete lifecycle of a networked control system, from design and installation to live operation and building maintenance.
PoE Network Advantages
- Power and data over a single-layer infrastructure using category cable
- DC power ideal for low-voltage LED and sensor applications
- Low-voltage and safe-to-install RJ-45 connections don’t require a certified electrician
- Ethernet standards are proven, future-proof, and scalable
- Enables advanced control of tunable LED luminaries and dynamic/bio-adaptive controls
- Enhances commercial building connectivity and data analytics
- Digital zoning and re-zoning make the building flexible to be optimized for the specific use and repurposed if future needs arise
- Easy convergence and integration with existing building automation systems (BAS) and infrastructure
- Granular sensor array for superior automation and data reporting
- Increases productivity and operational efficiency
PoE technology takes LED lighting in commercial spaces to the next level by further reducing energy consumption, improving the quality of light, enabling smoother intensity and dimming functions, and dynamically adjusting color temperature to create more comfortable and productive work environments. These systems also provide owners and operators with ready access to light status, real-time energy consumption, sensor-based occupancy reporting, air quality, temperature, and other environmental monitoring. Aggregate data like this can translate into tangible business insights in terms of flow patterns and space utilization, conditions within those spaces, and how different spaces, floors, or buildings rank or compare in terms of utilization, energy usage, and productivity.
The elimination of a dual-layer infrastructure to distribute power (e.g., AC main) and another to provide communication, data, and control either wirelessly or on low-voltage cables makes new construction simpler and faster than traditional hard-wired AC/DC distributed lighting and automation systems. Powered with an RJ-45 connector, each LED light or element in the building receives an IP address. Changes in space utilization reduce both installation time and cost and eliminate wiring rework. A network-connected system allows rapid changes in device parameter settings and zone programming simply by reassigning sensors depending on space utilization needs.
PoE is one of the most promising technologies in the move towards IP convergence for lighting and other building automation networks. With the help of experienced partners, building owners can take advantage of this powerful technology.
by Giovanni Frezza, Group Product Manager, Molex. Molex is a leading provider of global electronics components and solutions.