Simulation study on ventilation design for controlling gaseous pollutants in urban sentry boxes with opening window

Abstract

In cities, sentry boxes with various service functions can be seen everywhere, such as mobile security booths, toll booths, etc., which play an important role in public social services of their compactness and convenience. To realize the office function, the sentry boxes located by the road often need to open the work window continuously or frequently. With the flow of natural wind, various pollutants easily intrude into the sentry box from the open window, resulting in the deterioration of the indoor air quality and a threat to employees' health. In this paper, two attached ventilation modes are used as the carrier, and NO2 is selected as the outdoor gaseous pollutant to discuss the ventilation scheme design to improve air quality in the sentry box with an opening. The barrier performance of the air curtain formed at the window to outdoor pollutants was studied in the vertical wall-attached ventilation (VAV) mode. The conclusion is that although there is an entrainment phenomenon, as long as the supply air velocity is sufficient to generate a covering air curtain (Us > 1 m/s) at the window, the intrusion of pollutants can be effectively blocked. The horizontal wall-attached ventilation (HAV) mode represents the scheme that the supply air jet's mainstream area is far from the opening. The analysis shows that the reasons for improving indoor air quality are the dilution of fresh supply air and the suppression of positive pressure. This paper's conclusions can guide the ventilation design of sentry boxes with openings.