1. (1) WattDepot: A software ecosystem for energy data collection, storage, analysis, and visualization Robert S. Brewer, Philip M. Johnson Collaborative Software Development Laboratory Information and Computer Sciences Dept University of Hawaii at Manoa http://csdl.ics.hawaii.edu/

2. (2) Motivation Research on changing energy use behaviors Need to collect & analyze energy data Requirements Collect data from many meters Sub-minute data collection Easy to simulate sensor data Internet-accessible repository Visualization variety & flexibility Open source Could not find an existing solution Developed WattDepot

3. (3) Architecture Devices Meters WattDepot Sensors WattDepot Server WattDepot Clients HTTP

4. (4) Sensors Software to collect data Interface to specific meters Store data in server via HTTP Designed for flexibility Encapsulates vendor-specific code Any platform or language Just needs to output XML over HTTP Current implementations TED 5000 home energy meter Veris power meters Modbus/TCP meters Sensors Server Clients

5. (5) Servers Central data repository RESTful HTTP API Pluggable back-end database Data represented as XML or JSON Devices represented as Sources Server-side capabilities Aggregation of sources (virtual sources) Data interpolation Sensors Server Clients

6. (6) Servers: Virtual Sources Virtual sources combine sub-sources Maps real-world entities to system Hierarchy can be multi-level But meter clocks may not be synchronized Saunders Hall Floor 2 North Saunders Hall Floor 2 South Saunders Hall Floor 2 Saunders Hall

7. (7) Servers: Timestamp Problem Unsynchronized clocks cause problems Naïve data comparison difficult

8. (8) Servers: Data Interpolation Data resampling at arbitrary times Linearly interpolate between data points Solves timestamp problem for virtual sources

9. (9) Clients Data extraction & visualization Any platform or language Using REST or Google Visualization APIs Current implementations Real-time monitors Charts Geographic visualizations Android mobile application All independent of data input source Sensors Server Clients

10. (10) Clients: Heatmap and Gauge

11. (11) Clients: GeoMap

12. (12) Related Systems Pachube Commercial hosted data storage YouTube for sensor data Limits on rate of data storage Arbitrary data means no energy “smarts” Google PowerMeter Smart meter data storage & visualization Data limited to 15 min intervals Focus on single-family homes

13. (13) Our Application Dorm energy competition 30 floor-level meters Real-time data Extensive competition web app Customized goal-based visualizations Google Spreadsheet intermediary High performance “cloud cache” Build higher-level data abstractions Easy to prototype visualizations Simulated energy data critical Allows progress while meters are installed

14. (14) Dorm Energy Visualizations

15. (15) Future Directions Privacy Sources currently public or private Limited authentication support All current applications use public data Data aggregation Needed when comparing private data Sensors Additional meter support

16. (16) System Availability Hosted on Google Code http://code.google.com/p/wattdepot/ Open source under New BSD license Discussion list http://groups.google.com/group/wattdepot- users

17. (17) Q&A Ask away! Contact: rbrewer@lava.net, johnson@hawaii.edu