“…Therefore, the chiller's operation strategies of HVAC systems are highly effective in energy-saving based on their configuration, single or multi-chiller, and whether the multi-chiller is equal in size (symmetric) or different sizes (sequential) [9]. In general, the capacities of chillers in multiple-chiller systems are identical due to the convenience of control, installation, and maintenance [10]. The sequential or different sizes of multi-chillers are the best energy-efficient system due to allowing more alternative scenarios of choosing the appropriate chiller size to meet the current cooling load [11,12].…”