Assessing occupants’ energy-load variation in commercial and educational buildings: Occupancy detecting approach based on existing wireless network infrastructure

ABSTRACT Providing energy-consumption feedback has the potential to change people's behavior, a reality that has led to significant energy-usage reductions in residential buildings. However, it is challenging to provide feedback in commercial and educational buildings because it is difficult to track occupants' behaviors and their corresponding energy usage-especially for temporary occupants. In order to make providing such feedback possible in commercial and educational buildings, this paper presents a coupled system that monitors the energy load for occupants who have WiFi-enabled devices. The system benchmarks energy loads using an energy monitoring system that simultaneously detects occupancy and roughly estimates the residents' location through Wi-Fi access points. A preliminary experiment was conducted in an educational building to illustrate the data processing procedure and to test the validity of the system. The experiment results suggest the event of wireless connection is a valid indication of energy load variation. The proposed system is the prototype of a coupled system that, in the future, will be able to estimate individual's energy load through an indoor positioning system and, in turn, provide corresponding energyconsumption feedback. INTRODUCTION Buildings account for 40% of all energy consumed every year, making them the largest consumer of energy in the U.S. (U.S. Department of Energy 2011). Residents in commercial and educational buildings significantly contribute to and exercise a great control over a significant amount of the energy end-uses, such as lighting, space heating, space cooling, electronics and appliances (U.S. Department of Energy 2011). Conventional approaches toward enhancing building energy efficiency focus on building envelope retrofitting and system update. However, such approaches require large capital investments and sometimes are infeasible. Recently, researchers propose that changing people's behavior by providing high resolution feedback has a great potential to contribute to the reduction of energy consumption. Feedback, in the context of energy-related research, means all levels of information related to energy consumption that may be provided to energy end-users. By providing real-time energy feedback to occupants, researchers observed up to a 46% reduction in consumption in residential building