Experimental study on the flow field and economic characteristics of parallel push-pull ventilation system

Push-pull ventilation systems provide excellent control of contaminants and harmful gases. However, since both a push inlet and a pull outlet are used in the push-pull ventilation system, the flow rate required by the system is large. In that case, the energy consumption of the system is large. The purpose of this paper is to study the flow field and economic characteristics of a parallel push-pull ventilation system by reducing the flow rate of the exhaust outlet, which will be achieved by reducing the size of the exhaust hood. The three commonly used push-pull ventilation systems were analyzed: a high velocity push-pull system with high air supply velocity, a low velocity push-pull system with wide airflow and small velocity, and a parallel push-pull system with wide airflow and uniform air supply velocity. Results showed that the parallel push-pull ventilation system was the only one in which the flow rate of the exhaust outlet could be reduced, reducing the overall energy consumption. Under conditions of the parallel air supply jet, the diffusion range of contaminants in the push-pull flow field was the smallest and reducing the exhaust air flow rate did not affect the capture efficiency of pollutants. These results may be useful in guiding the design of push-pull ventilation system and optimize economic constraints. © 2020