Use of Modelica to predict risk of Covid-19 infection in indoor environments

In the light of the Sars-CoV-2 pandemic, the dispersion process of respiratory droplets released by potentially infected persons has been investigated in many studies using highly reliable but time consuming CFD methods. With such simulations social distancing, wearing masks and shifts in ventilation systems could be justified. This work focuses on the same topic but uses the validated Velocity Propagating Zonal Model (VEPZO) instead of CFD simulations. It is implemented in Modelica and allows fast simulation of the indoor environment on a coarse grid which in many cases is a superior alternative to complex CFD simulations in the trade-off between effort and detail of the result. Based on the temperature and airflow distribution, this model can be used to predict the dispersion of aerosols in enclosed spaces and thus the relative risk of Covid-19 infection. For model verification, a documented outbreak in a restaurant in Guangzhou is being investigated. An improved ventilation pattern to contain viral load more locally is developed.