Minimizing Primary Energy Consumption in District Cooling System: A Showcase of the Impact of Online Optimization Control (ST-16-C019)

District cooling system (DCS) consists of chillers, cooling towers and pumps, and is widely used owing to high energy efficiency. However, due to higher energy costs and greenhouse gas emission issues, more energy-efficient total plant operation, not only the chiller system but also the cooling water system, is required to reduce the energy consumption and CO2 emission. In this report, we will present real-time online optimization control, to minimize the energy consumption, in district cooling plants.  As well as the theoretical background for real-time online optimization control methodology, the report contains examples of successful application including the reduction in primary energy consumption rates. Herein, the objective function of the optimization is to minimize the primary energy consumption rate whilst satisfying chilled water demand, and the optimization controls are constructed and realized by:  Optimum Chiller control, Optimum cooling tower control, Optimum cooling water pump control, Optimum primary pump control and Optimum secondary pump control. The effectiveness of the real-time online optimization control methodology and the actual reduction of the primary energy consumption by applying the optimization are shown based on the result of operation data.