Plug loads as devices plugged into an electrical outlet, are becoming more widespread and consume an increasing share of commercial-building energy use. While other technologies like lighting have become more energy efficient, the diverse natures of plug-load devices have made it difficult to manage them for energy and demand savings. Plug-load devices range from specialized laboratory equipment to common-area appliances and individually assigned equipment like mobile devices.
Researchers designed plug load technology innovations for energy and demand savings. These were tested with commercially available plug-load energy-management systems using smart outlet automation in two pilot sites: an architectural office building and a university biologyresearch laboratory. These systems monitored electricity use by minute and managed the automation of smart-outlet technology with different strategies.
Energy and demand savings depended upon device type and user setting. In the office building, the team tested 54 smart strips at workstations and in common areas for energy savings; energy use was reduced by 10.7 percent. In the biology lab, 76 plug loads were monitored with 21 devices, which were put on time schedules so their energy savings could be evaluated and 18 were analyzed for energy savings; energy consumption by the 18 devices was reduced by 18 percent. The project team also developed and tested a demand-response notification system, which demonstrated the potential for laboratories to effectively contribute to 22 percent demand load reduction from one specific demand response event.
The project identified promising potential for energy efficiency and demand reductions with commercial plug loads. The high cost of plug-load energy-management systems and their long payback period range from the coffee maker which is 1 year to a charger which is 98 years. Market acceptance requires value-added benefits greater than the cost and effort required of building owners and facility managers to implement them. Some recommended pathways for wider market adoption are also included in this report.
