Lighting and Cooling Systems Controlled via the Internet
California utilities must cut peak load demand for electricity by 4 percent this year and by 5 percent during 2007. As a result, Edison researchers are constantly evaluating new technologies to provide better opportunities to reduce the peak electric system load.
Peak load refers to the stress on the electric grid which occurs when demand for electricity nears the capacity of the available power generation. Hot summer afternoons are historically the time for the most stress to the grid. Weather forecasts are used to predict when demand reduction tactics will need to be used and provide a degree of planning for electric load curtailment. Power generation or electric grid malfunctions result in an immediate need to reduce electricity consumption.
Southern California Edison (SCE) will benefit from technologies that allow the utility to reduce loads upon command. Fast responding systems provide the flexibility to be the most useful. The larger the load that can be controlled the more useful. Large load reduction can be achieved by a few major facilities or by smaller load reductions at many facilities. Technology is providing ways to coordinate larger groups of customers to participate in organized demand response programs.
SCE tested the implementation of a new wireless energy management system to control lighting and a chiller at a pilot test facility. The system controls the level of dimming in dimmable ballasts in fluorescent ceiling lighting. The control system also cycles the chiller by turning it on or off.
The project had four main objectives:
- To determine if SCE could control external load from our facilities.
- To determine if this approach would work for lighting and chiller loads.
- To determine how long it takes from the time the command is given until the load responds.
- To determine how much load is shed.
A Los Angeles County medium-sized office building with 2-lamp, T8 fluorescent recessed ceiling fixtures was selected for the series of tests. Twenty-nine dimmable ballasts were controlled by a wireless energy management system which allowed lighting to be dimmed to 30 percent, 50 percent, 60 percent and 70 percent levels. Response times ranged from 6 to 12 seconds. Lighting level measurements were made to quantify the dimming settings. The reduction in load recorded per fixture was 22.7 W when lighting was dimmed from 70 percent to 30 percent.
The energy-management system was also used to control the chiller. Response times were between 50 and 80 seconds. The chiller shed 37.5 KW.
The project is important because it verified that load could be controlled from multiple remote locations with an acceptable response time.
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