Robustness enhancement for chiller sequencing control under uncertainty

Chiller sequencing control is an important technique for achieving energy efficiency of multi-chiller plants while not sacrificing indoor thermal comfort. Available typical controls, such as bypass flow-based control and direct power-based (P-based) control, uses individual indicator to switch chillers on or off. However, these controls suffer from various uncertainties in operation and may lead to insufficient cooling supply, unstable operation, or energy waste. A simple but practical way to enhance the robustness of chiller sequencing control is to explore and make use of the complementarity of different load indicators. Hence, this paper presents three methods to enhance the robustness of chiller sequencing control by hybridizing the use of different load indicators. Numerical studies are used to analyze the robustness of the enhanced controls under different levels of uncertainty.