A new pump speed control method for the primary-secondary system is developed and presented in this paper. The distribution (secondary) pump speed is controlled to maintain the optimized system resistance to make the coil valves open. The system resistance can be obtained by the pump head and the water flow rate, which is calculated by the recently developed pump water flow station (PWS). The PWS measures the water flow rate using the pump head, pump speed, and pump performance curve. This method was proved experimentally in real HVAC systems. A case study is presented in this paper for application of this new method in a continuous commissioning practice. The case study shows that the PWS can control the pump speed to maintain optimized system resistance. It can also measure the water flow rate and monitor energy consumption continuously with minimal installation and maintenance expense. The results show that the new technology can save a significant amount of pump power and increase pump efficiency.

Units: I-P