Development and applications of fan airflow station and pump water flow station in heating, ventilating and air -conditioning (HVAC) systems

This dissertation describes the development and implementation of a new flow measurement method: the fan airflow station (FAS) and pump water flow station (PWS). This new technology provides reliable & accurate flow measurement, implementation of volumetric control in AHUs and pump, and monitoring the building energy consumption. It is very important to find an accurate and cost effective way to measure airflow or water flow in the HVAC industry. The FAS includes the fan head based (pressure-based) FAS and power-based FAS. The fan head based FAS measures airflow using the fan speed, fan head and in-situ fan curve. And the power based FAS measures airflow using the fan speed, fan power and in-situ power curve. The PWS can measure the water flow using similar algorithms. The theoretical background, models and instrumentation are presented in this dissertation. The accuracy of the FAS and PWS primarily depends on the accuracy of the fan/pump curve, because the fan/pump speed and fan/pump head can be measured accurately. An in-situ measurement method has been developed in this dissertation to generate the fan curve without interrupting normal system operations using the manufacturer's fan curve. The in-situ method only requires one direct airflow measurement if the manufacturer's fan curve is available. This dissertation introduces the theoretical model, measurement procedure and case study results to provide the general guideline for the in-situ curve measurement. The dissertation also describes and demonstrates FAS to the building pressure control (return fan speed control) and optimized supply fan speed control in real building HVAC systems. The application of PWS to the building energy monitoring, and optimized pump speed control are also introduced and demonstrated. The theoretical model was experimentally tested, and the excellent agreement between the model and the experimental values was found. The results show that the FAS/PWS can measure the airflow or water flow rate accurately with very low cost. It can improve comfort and save building energy consumption significantly to apply the FAS/PWS to HVAC systems. The in-situ curve measurement method has been also experimentally proven in full-scale AHU systems and can be adopted by the HVAC industry.