Development of methods for determining demand-limiting setpoint trajectories in buildings using short-term measurements

This paper presents simple approaches for estimating building zone temperature setpoint variations that minimize peak cooling demand during critical demand periods. Three different methods were developed that are termed the semi-analytical (SA), exponential setpoint equation-based semi-analytical (ESA), and load weighted-averaging (WA) methods. The three methods are different in terms of requirements for input data. The SA and ESA methods employ simple inverse building models trained with short-term data and use analytical solutions from the models to determine setpoint trajectories. The WA method is a data-based method in which an optimal weighing factor is found that minimizes a weighted-average of two loads and then used for weighted averaging of two initial bound setpoint trajectories. The weighted-averaged setpoint trajectory is adjusted to improve the load shape and can be updated on a daily basis. A companion paper [Lee K-H, Braun JE. Evaluation of methods for determining demand-limiting setpoint trajectories in commercial buildings using short-term measurements. Building and Environment 2007, in press, doi:10.1016/j.buildenv.2007.11.003] presents evaluations of the peak load reduction potential associated with implementation of these methods.