Enabling Residential Demand Response Applications with a ZigBee-Based Load Controller System

Home energy management (HEM) systems are getting increasingly popular in both academic and commercial communities. Most HEM solutions rely on either smart appliances or plugging traditional appliances into smart outlet/smart plugs which can communicate with the central HEM server. Conventional non-communicating power-intensive loads that are directly hard-wired to the supply panel of the house in the U.S., e.g., water heaters and clothes dryers, therefore are difficult to be made part of an HEM system. This paper describes the design and implementation of a microcontroller and ZigBee based load controller system that allows these loads to be controlled by an HEM system. The proposed system consists of four load controllers (LCs) that monitor and control four power-intensive household loads, and one communication controller (CC) that acts as a communication medium between LCs and a central HEM unit. The CC and all the LCs are packaged into one load controller box that can be placed beside the main circuit panel of the house and the wirings to the power-intensive loads are routed through the LCs. Within the box, the LCs and the CC communicate via hard-wired serial peripheral interface. The CC then communicates with the HEM system via ZigBee. The proposed system is expected to offer a cost-effective method to enable traditional hard-wired power intensive loads to participate in an HEM system.