Evaluation of an extremum seeking control based optimization and sequencing strategy for multiple-chiller chilled-water plant.

The ventilation and air conditioning systems of large commercial buildings are typically driven by chilled-water plants with multiple chillers. Real-time optimization and sequencing of such plants is thus critical for building efficiency (AHRI 2011). Due to the complexity and cost for calibrating chiller plant in field operation, model-free control has become an attractive solution. In an earlier study, Mu et al. (2015) develop an Extremum Seeking Control (ESC) based real-time optimization and sequencing strategy for a chiller-water plant with parallel chillers. Two schemes were proposed. For Scheme A, a chiller is turned on based on the measurement of chilled water valve position and is turned off when a chiller compressor is running at its nominal minimum speed. For Scheme B, a chiller is turned on and off based on the measurement of operating cooling load. Mu (2015) conducts a comprehensive simulation study on Scheme A. In this study, a comprehensive study is conducted for Scheme B under various scenarios and testing conditions, and the simulation results are compared with those from Scheme A.