Energy consumption of intermittent ventilation strategies of different air distribution modes for indoor pollutant removal

Efficient ventilation methods and ventilation strategies are required to improve the energy savings of the ventilation systems of industrial plants. This study investigated the energy-saving effect of intermittent ventilation strategies in industrial exhaust ventilation systems. First, the intermittent ventilation strategy under the ideal well-mixed ventilation model was studied. Next, the energy-saving effects of (vortex ventilation (VV) and downward-supply/upward-exhaust (DU) modes) on the intermittent ventilation strategy were compared. We used a genetic algorithm to accurately optimize the intermittent ventilation strategy, and a prediction model of indoor pollutants was established by combining computational fluid dynamics simulation results with an artificial neural network model. The results show that for an ideal well-mixed ventilation model, the main factors affecting the energy-saving effect of the intermittent ventilation strategy include the upper limit of the indoor pollutant concentration, durability of the fan, and operating air volume. With the upper limit of the indoor pollutant concentration and durability of the fan, the ventilation system may increase the operating air volume, often resulting in an increase in energy consumption for the intermittent ventilation strategy, possibly even higher than that of the continuous ventilation strategy. Moreover, when considering the ventilation air distribution mode, the time to reach stable airflow state also significantly affects the energy consumption of the intermittent ventilation strategy. When satisfying the time required to reach a steady airflow state, the ventilation system with the intermittent ventilation strategy can significantly reduce energy consumption, in which the energy consumption of the DU and VV modes is reduced by 44.17-62.25% and 51.69-60.68%, respectively.