Thursday, March 18, 2010

LEEDing to Better Building Control and Efficiency via Wireless Mesh Networks

LEED v3 has expanded the emphasis on measurement and verification (M&V) in order to offset concerns that green buildings don't maintain designed performance over time.

The rating system where this is most evident is in the LEED 2009 Existing Buildings: Operations & Maintenance (EB:O&M) If you dig through the credits with an eye towards the ones that:
  • Require or could benefit from some sort of real time or on-going monitoring
  • Could use a portable monitoring system comprised of sensors and small data network.
  • Address the toxicity and recycle-ability of the sensor & networking systems
You find that something on the order of half of the credits (around 46 of 92 when I last checked) could be affected by having a good sensor system available.

Sensors, of course, need a communication network to feed their data back to a building automation system, (BAS) or building management system (BMS). If you are forward thinking and lucky enough to be engaged in new construction, then you can build many of these networks into the plan. Then when you meet the USGBC requirement for ongoing performance monitoring by following the EB:O&M certification route, you will be ready. For new construction, this is probably a good way to go.

However, if you're in the position of having an already complete building and you want to obtain EB:O&M, getting such a network in place could cost a considerable sum due to the wire routing involved. In such cases, using a low power wireless network would be preferable. Given the large area to be covered by a wireless sensor network and the large number of discrete sensors needed, this kind of application lends itself to a wireless mesh network (ala IEEE 802.15). Basically a network that uses the nodes to communicate with each other rather than requiring all units to communicate with a central access point. The more nodes (sensors) in place, the better the network becomes... and it's low power enough to run on batteries for months at a time... important if you need to pay someone to replace all those batteries.

UC Berkeley has pioneered work on this topic, coining the phrase "smart dust," and spun off at least one company (Archrock) that aims to address this kind of market space.