Low-cost appliance state sensing for energy disaggregation

Abstract

Reliable detection of appliance state change is a barrier to the scalability of Non Intrusive Load Monitoring (NILM) beyond a small number of sufficiently distinct and large loads. We advocate a hybrid approach where a NILM algorithm is assisted by ultra-low-cost outlet-level sensors optimized for detecting appliance state change and communicating the event on a best-effort basis to a central entity for opportunistic fusion with the state change detection mechanism within NILM. In support of such an approach we present the implementation of an appliance power state sensor which achieves low cost via design choices such as a transmit-only radio. We also present results from a study where the sensors tracked power states of tens of appliances with high accuracy.