About 15 years ago, LED light sources were mainly cost-effective for exterior lighting and specialty lights, such as traffic lights. As LED brightness and color balance have improved, costs also have come down. As a result, LEDs are now practical for automotive lighting, interior building lights, and even residential lighting. Over this same 15-year span, PoE technologies also have advanced with the development of software control features and lower costs. And the specific features of LED lighting are well suited for use with the power levels and energy management features of PoE systems.
LED lights operate with low-voltage dc power. Mains power is ac, and depending on the country, delivered at 110 V to 230 V. Thus, most LED lights used with mains power in residential and commercial buildings must incorporate a converter. This is inefficient, and an extra cost. PoE systems, on the other hand typically provide 15 to 90 W of dc power at voltages typically below 60 V. The amount of money saved by avoiding the inefficient conversion can be substantial even for small buildings – thousands of euros per year. What’s more, the PoE power supply equipment can sense the power level needed and adjust accordingly.
When used with photodetectors, motion sensors, and other controls, the LED light and PoE delivery system form smart-lighting hub. The Ethernet switch can turn lights up or down if rooms are unoccupied. Further, it can reduce artificial lighting to take advantage of sunlight, and it can balance the use of daylight with the need for air conditioning or heating as parts of the building become warmer than others.
Although LED lighting and PoE systems seem particularly well suited to work together, there are many other systems that can take advantage of PoE to reduce installation costs as well as power and other operating expenses.
Examples of PoE powered devices (PDs) include: