Ventilation design of tour buses for suppressing airborne transmission and highly efficient virus elimination in post COVID-19 period

Abstract

Measures to prevent the spread of COVID-19 are critical across the globe. A tour bus can carry passengers; however, the small, closed space becomes congested owing to their presence for long periods. Therefore, there is an increased risk of infection on tour buses. The air outlet of the air conditioner in a tour bus was designed to prioritize heating and cooling over ventilation. This study aims to improve the ventilation performance of tour buses. Therefore, a large-scale ventilation simulation was performed using a supercomputer. The results are as follows: (1) when the overall air flow rate of the ventilation is fixed, new outlets must be installed in the upper rear part of the tour bus for rapid ventilation; and (2) the ventilation efficiency was higher when a few highoutput outlets were installed instead of several low-output outlets. The reason for the more effective ventilation was to create a large airflow in the tour bus. We proposed the design of a highly efficient ventilation system in an existing bus space and elucidated the appropriate layout of ventilation outlets and the optimal protocol for opening windows.