One of the most anticipated home energy management and monitoring systems didn’t come from one of the big home control companies at the recent CEDIA Expo in Indianapolis. It’s from power control company Eaton, whose smart circuit breakers captured the imaginations of many when it was first seen last year.
Now the Eaton Smart Energy Management System (ESEM) will be launched in two months, for both homes that have access to electric utility-based smart grid offerings and as a standalone system for homes without smart grid access. With it you can get some pretty good energy management and monitoring in your house for about $1,000. It should also be easy to retrofit—and can control and monitor Eaton’s electric vehicle (EV) charger (another $1,000). This could be the mid-market energy management solution that many are looking for.
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Why? The system can monitor the home’s overall electricity consumption, as well as that of some individual circuits and devices plugged into wirelessly communicating modules. It can also turn on and off circuits and the devices plugged into the modules at preprogrammed times or in response to utility pricing if smart grid services are offered.
The system uses wireless RF-based ZigBee technology to communicate to and from a 5-inch touchscreen, wireless thermostat, Smart Energy Receptacle plug-in modules, and a Smart Loadcenter Module that is wired to the electrical panel.
Eaton chose the ZigBee wireless technology because it is likely to be used to communicate pricing and other signals from smart grid-based two-way smart meters to home systems. This way, it can be used both by homes that have access to smart grid services and by those homes that don’t yet have these services.
Innovative Smart Breaker
A big part of the system are the Smart Breakers that can be used to turn off individual circuits in an electrical panel. A ZigBee wireless signal is sent from the controller to the Loadcenter, which is wired to the breaker. A solenoid on the breaker turns it off without “tripping” the circuit, says Eaton product manager Dave Richards. This is useful for operating big appliances like air conditioners, water heaters or pool pumps.
Circuits also can be shut off automatically via programmed schedules or in response to pricing signals from the utility. (Utilities offering smart grid services typically implement Time of Use rates that price electricity higher during peak load periods, such as dinnertime. So many will opt to delay or “load shift” the energy used by their appliances and EV chargers to other, less expensive times.)
In addition, current transformers (CTs) measure the amount of electrical current from the two mains (for whole-house) and individual circuits. The CTs are also wired to the Smart Loadcenter near the electrical panel, which sends and receives wireless ZigBee signals to the touchscreen controller.
Smart Receptacle plug-in modules can be placed around the house to measure the usage of individual devices and turn those devices on or off.
Sticking to Basics
The dashboard on the 5-inch touchscreen shows a speedometer-like readout of how much energy is being used in the house, then breaks it out to those devices and appliances that are being monitored. There can be individual pages showing bar graphs for the usage of the water heater, pool pump and vehicle charger, for example. An Away mode can turn devices off and set back the thermostat.
“We only going to look and maybe capture the big loads through the house. We see 8 to 10 you might monitor,” says Richards.
A Smart Loadcenter with three CTs plus two for the mains is $500, with the necessary touchscreen controller adding another $500—so there’s the $1,000 basic system. Smart Breakers will run $30 to $70 and Smart Receptacles $75. Each Loadcenter can handle four circuit monitoring CTs and the two main CTs, in addition to four single-pole breakers (for standard 120-volt usage) or three double-pole breakers (for 240-volt appliances such as ovens, EV chargers, etc.). If you want to add more, the Smart Loadcenters can be ganged.
Eaton’s system appears to be well thought-out and positioned for both smart grid and non-smart grid homes. It can monitor and control a home’s big energy hogs and individual devices plugged in around the house. It offers wireless thermostat control and programming as well. It’s not a full-fledged automation system, but provides about as much energy management as a house needs—all in what appears to be a fairly flexible package.