SAGA: Tracking and Visualization of Building Energy

In this paper, we present SAGA, a system for building energy management that provides robust multi-hop wireless sensing, actuation, device management, plotting of historical data and a server backend API to support remote access. Information collected from sensor nodes is stored locally for quick retrieval even if outside network connectivity is lost or unavailable. When network connectivity is available, data is pushed using the extensible Message Passing Protocol (XMPP). This enables external server-side archiving of historical events and additional processing as well as secure bi-directional communication from gateways behind firewalls or with dynamic IP address like those found in broadband connected homes. SAGA provides a web interface that allows devices to be easily configured with aliases and grouped together based on sensor type. Individual and groups of sensors can be plotted to show relative comparisons of different sensor values. For example, selecting to plot a group of energy metering devices shows the overall distribution of energy consumption per-device. A local multi-resolution storage system provides optimized access to recent high-resolution data along with quick retrieval of pre-computed long-term averages. SAGA has been deployed in three homes around the Pittsburgh area, collecting data for more than two years.