Bridging energy harvesting wireless sensor networks to TCP/IP

Technology eliminates traditional installation barriers, opening new opportunities for building automation

Introduction
Buildings account for 40 percent of all energy consumed in the United States  and according to the AIA, approximately 50 percent of greenhouse gas emissions. Building Automation Systems (BAS) are proven to reduce energy consumption on average 40 percent. Unfortunately, most buildings still do not benefit from the energy savings of BAS nor do they contain the cabling necessary for wiring the essential sensors and controls. Adoption of building automation has been hindered by many factors, primarily the following:

-    Existing buildings have been expensive to retrofit (installation costs, slow payback)
-    Retrofitting existing buildings with BAS is invasive, often complicated and potentially risky (e.g., building closures, unknown variables behind walls/ceilings, exposure to asbestos)

These classic barriers have been overcome by an ecosystem of wireless controls that power themselves using energy infinitely available in office building spaces – indoor light, motion and temperature differences. It is now possible, with low investment and minimal disruption, to outfit buildings with self-powered, “peel & stick” sensors and switches that seamlessly connect into TCP/IP communications. The newfound simplicity and low cost are important catalysts to make buildings more energy efficient.

“This trend to centralize and converge building energy management is key, given the fact that only five percent of small and medium-sized buildings (100,000 square feet or less) are equipped with a building management system,” said Kirsten West, principal analyst at West Technology Research. “Small and medium-sized facilities account for 98 percent of all buildings and 65 percent of floor space, making this segment the largest under-served market in the industry by far. That is why the ability to populate a facility with sensors that can communicate over TCP/IP to a centralized building automation system is key to this Greenfield market segment.”

Limitless supplies of energy
Before energy harvesting sensors and switches were invented, integrators were limited to line-powered or battery-powered devices. Wires pose difficultly in reaching all corners of buildings, and batteries introduce intolerable maintenance issues into the mix. In the early 2000s, EnOcean introduced an energy harvesting wireless standard that transcended the limits of wires and batteries. The wireless standard and technology stemmed from a simple observation – in the same spaces where building sensor information resides, sufficient energy exists to power sensors and radio communications. Since its inception, applications for self-powering wireless sensors and controls for use in building automation have steadily increased. Lighting and HVAC energy management systems provide a rich habitat for the development of sensor-driven solutions that regulate energy flow in buildings. Now, more 850 EnOcean-based devices are available and the controls have collectively been installed into 200,000 buildings worldwide.