tion, as well as a wireless or cellular connection. Each option has pros and cons, depending on the needs of the facility, and facilities must examine each option when working with an energy service provider. For example, a hardwired connection is typically more reliable, while a cellular connection could be more costly because it would require a cellular data plan for the system. Facility managers are often advised to adopt systems that communicate through an open protocol that integrates utility OpenADR signals with onsite BACnet controls. The BACnet open protocol also offers the flexibility to make future upgrades or switch building controllers, helping to better future-proof the entire system. BACnetenabled devices, like other ADR client devices, can manage the connected control system’s energy usage and report back real-time consumption rates for facility managers to more accurately monitor and gain insight into a facility’s overall energy consumption trends. Another significant advantage to BACnet is that it allows facility managers to predefine the command priority level, with up to 16 levels support- Figure 2: The OpenADR specification enables utilities to use demand response automation software to send price and reliability signals over the Internet to existing customers using a set OpenADR message. (courtesy: Demand Response Research Center/Lawrence Berkeley National Laboratory) www.info.hotims.com/37992-57 November 2011 B A C n e t ® To d a y & t h e S m a r t G r i d | A S u p p l e m e n t t o A S H R A E J o u r n a l B31