Analysis of Condenser Loop Flow Rates and Effect on Overall Cooling Station Power Consumption: A Case Study

In the past, researchers have investigated the usefulness of reducing condenser loop flow in chiller systems. Some have reported significant energy savings when reducing flow from constant condenser loop flows of 3.0 GPM/t (kg/s/kW), while others found minimal benefits. In this study, a model of a real chiller-cooling tower station was built in Modelica and validated for various operation conditions. Test simulations were performed to calculate optimal constant condenser flow rates and quantify savings from varying optimal condenser loop flow rates. Full-year simulations were conducted using operating conditions from two district cooling systems in different climates. The results indicate that the benefit from variable condenser water flow depends primarily on the load variation and then on the ambient dew point temperature. The study shows that for cooling loads with significant seasonal variation and climates with low yearly wet bulb temperatures, varying optimal condenser flow can reduce energy consumption up to 2.3%.