Evaluating the potential of airflow patterns to maintain a non-uniform indoor environment

Individual parameters are often required in shared indoor areas simultaneously. Therefore, a ventilation design should consider multi-location individual requirements. To aid in the design of an energy-efficient ventilation system that is oriented toward individual requirements, an evaluation index—difference potential by supply air (DPSA) is defined based on an analytical expression for a transient parameter under a fixed flow field. The reliability of the DPSA index is subsequently verified by personalized ventilation. The DPSA index is then applied to evaluate the potentials of seven airflow patterns and a variable air volume (VAV) system in zonal control in a subway control center. It is concluded: (1) The DPSA index quantifies the realizable parameter difference between two arbitrary locations or zones for an airflow pattern. It is reliable to evaluate the potential of airflow patterns to maintain a parameter difference. (2) Different potentials for maintaining parameter difference are found for different airflow patterns. Even for one specific airflow pattern, the potentials among different zones are different. (3) It is difficult to maintain a parameter difference between two neighboring zones. However, a certain parameter difference may be maintained between two zones that are far away from each other. This research may elucidate the potential of airflow patterns to maintain a parameter difference and may provide guidelines for a non-uniform indoor environment.