Reconciling airborne disease transmission concerns with energy saving requirements: the potential of UV-C pathogen deactivation and air distribution optimization

TL;DR

This study explores low-energy HVAC modifications, including UV-C disinfection and optimized air vent placement, to reduce airborne disease transmission risk while maintaining energy efficiency in buildings.

Contribution

It demonstrates the effectiveness of UV-C modules and strategic vent placement in improving indoor air quality and reducing energy consumption.

Findings

UV-C modules effectively inactivate airborne pathogens.

Optimized vent placement enhances ventilation efficiency.

Indoor air quality maintained with reduced energy use.

Abstract

The COVID-19 pandemic caused a paradigm shift in our way of using heating, ventilation, and air-conditioning (HVAC) systems in buildings. In the early stages of the pandemic, it was indeed advised to reduce the reuse and thus the recirculation of indoor air to minimize the risk of contamination through inhalation of virus-laden aerosol particles emitted by humans when coughing, sneezing, speaking or breathing. However, such recommendations are not compatible with energy saving requirements stemming from climate change and energy price increase concerns, especially in winter and summer when the fraction of outdoor air supplied to the building needs to be significantly heated or cooled down. In this experimental study, we aim at providing low-cost and low-energy solutions to modify the ventilation strategies currently used in many buildings to reduce the risk of respiratory disease transmission. We find that ultraviolet germicidal irradiation (UVGI) modules added to the HVAC system are very efficient at inactivating pathogens present in aerosols, leading to good indoor air quality even with significant indoor air recirculation. Moreover, we show that an optimal placement of the air exhaust vents relative to air supply vents can improve the ventilation efficiency, with significant consequences in terms of energy savings.