Building Energy Management as Continuous Quality Control Process

This paper describes a macroanalytic approach to energy management in buildings. Conventionally, energy improvement measures are designed and deployed in buildings, expecting and typically achieving energy savings from changes to the building envelope or energy systems such as lighting system retrofits. However, additional savings opportunities can be identified by analyzing the interaction between building systems and the influence of building occupants. An energy accounting system can provide the required wealth of data and information and facilitate the analysis on which to design and refine further retrofit measures. The problem of energy management is cast in the framework of a classical feedback control loop: A "sensor" (energy accounting system) monitors the utility consumption of the building in question, compares it with predefined "setpoints" (energy consumption targets) and analyzes the deviations within a comprehensive reporting system (the "controller"). In response to the analysis, adequate measures including occupant motivation are defined by the controller and applied by the "actuator" to the "system," embracing the building and its occupant under the prevailing weather conditions. The system output is the actual energy and utility consumption that is compared with the target values, and the loop is closed. The paper discusses an implementation of an energy management system that has been applied successfully to the measurement and verification of utility cost savings in an energy savings performance contract in Germany. Building occupant motivation—a category of energy retrofit measures that is often overlooked—is presented. A set of tabular and graphical data illustration and analysis techniques is presented along with recommendations for building occupant motivation measures and associated implementation guidelines.