Effective management of plug loads in commercial buildings with occupant engagement and centralized controls

Abstract

Plug loads, or devices plugged into wall outlets, comprise a growing proportion of commercial building electricity consumption. This study presents the results of a hybrid approach for plug load management, which includes a combination of occupant engagement and centralized controls. Electricity consumption was monitored for 249 plug load devices in the XFINITY Center at the University of Maryland. After a baseline monitoring period, 1) on-off schedules were set for 78 devices in the concession stands, and 2) 31 office occupants in the facility took part in an energy competition and were given access to a mobile energy app (Keewi, Inc.) to control their 115 devices. Centralized controls resulted in a reduction of 58% in consumption in the concessions during the days when the concessions were not in use. Occupant engagement led to a reduction of 32% in plug load electricity consumption in the offices. Savings were largest in high-consumption categories such as merchandisers and food preparation chillers in the concessions, and IT equipment, refrigerators, desktop computers, and space heaters in the offices. The study indicates the benefits of hybrid approaches to plug load management given unique facility characteristics.