Wireless Infrastructure for Performing Monitoring, Diagnostics, and Control HVAC and Other Energy-Using Systems in Small Commercial Buildings

This project focused on developing a low-cost wireless infrastructure for monitoring, diagnosing, and controlling building systems and equipment. End users receive information via the Internet and need only a web browser and Internet connection. The system used wireless communications for: (1) collecting data centrally on site from many wireless sensors installed on building equipment, (2) transmitting control signals to actuators and (3) transmitting data to an offsite network operations center where it is processed and made available to clients on the Web (see Figure 1). Although this wireless infrastructure can be applied to any building system, it was tested on two representative applications: (1) monitoring and diagnostics for packaged rooftop HVAC units used widely on small commercial buildings and (2) continuous diagnosis and control of scheduling errors such as lights and equipment left on during unoccupied hours. This project developed a generic infrastructure for performance monitoring, diagnostics, and control, applicable to a broad range of building systems and equipment, but targeted specifically to small to medium commercial buildings (an underserved market segment). The proposed solution is based on two wireless technologies. The first, wireless telemetry, is used for cell phones and paging and is reliable and widely available. This risk proved to be easily managed during the project. The second technology is on-site wireless communication for acquiring data from sensors and transmitting control signals. The technology must enable communication with many nodes, overcome physical obstructions, operate in environments with other electrical equipment, support operation with on-board power (instead of line power) for some applications, operate at low transmission power in license-free radio bands, and be low cost. We proposed wireless mesh networking to meet these needs. This technology is relatively new and has been applied only in research and tests. This proved to be a major challenge for the project and was ultimately abandoned in favor of a directly wired solution for collecting sensor data at the building. The primary reason for this was the relatively short ranges at which we were able to effectively place the sensor nodes from the central receiving unit. Several different mesh technologies were attempted with similar results. Two hardware devices were created during the original performance period of the project. The first device, the WEB-MC, is a master control unit that has two radios, a CPU, memory, and serves as the central communications device for the WEB-MC System (Currently called the 'BEST Wireless HVAC Maintenance System' as a tentative commercial product name). The WEB-MC communicates with the local mesh network system via one of its antennas. Communication with the mesh network enables the WEB-MC to configure the network, send/receive data from individual motes, and serves as the primary mechanism for collecting sensor data at remote locations. The second antenna enables the WEB-MC to connect to a cellular network ('Long-Haul Communications') to transfer data to and from the NorthWrite Network Operations Center (NOC). A third 'all-in-one' hardware solution was created after the project was extended (Phase 2) and additional resources were provided. The project team leveraged a project funded by the State of Washington to develop a hardware solution that integrated the functionality of the original two devices. The primary reason for this approach was to eliminate the mesh network technical difficulties that severely limited the functionality of the original hardware approach. There were five separate software developments required to deliver the functionality needed for this project. These include the Data Server (or Network Operations Center), Web Application, Diagnostic Software, WEB-MC Embedded Software, Mote Embedded Software. Each of these developments was necessarily dependent on the others. This resulted in a challenging management task - requiring high bandwidth communications among all the team members. Fortunately, the project team performed exceptionally well together and was able to work through the various challenges that this presented - for example, when one software tool required a detailed description of the output of a second tool, before that tool had been fully designed