Optimal Pump Speed Control in a Chilled Water System

Traditionally, chilled water pump speed is modulated to maintain the water loop differential pressure set point and the control valve at the air handling unit (AHU) is modulated to maintain the supply air temperature. This paper introduces a new VFD pump speed control algorithm, optimal pump head control strategy. The algorithm focuses on minimizing the water loop differential pressure in order to reduce the overall pump energy consumption. The new algorithm is implemented in a real chilled water system. The pump power consumption is compared between the traditional algorithm and new algorithm. The implementing result demonstrates that the new algorithm results in improved pump efficiency, reduced pump head and pump speed and remarkable energy savings.