A multifaceted analysis of COVID-19 propagation in confined spaces: a techno-economic assessment of ventilation, heating, and renewables integration
The outbreak of novel coronavirus disease 2019 (COVID19) has spread rapidly, affecting nearly all countries and territories around the globe, impacting every aspect of human life. Governments and various organizations worldwide have issued mitigation measures to counteract COVID-19 virus propagations, whether in indoor spaces or outdoors. Although the underlying uncertainty concerning COVID-19 transmission details, most international organizations such as WHO, ECDC, ASHRAE, REHVA, and CIBSE agree on the important role of ventilation to minimize the causes and reduce the viability of SARS-CoV-2 in confined spaces. Given that natural ventilation is variable, which depends on the intermittent wind source, mechanical ventilation systems provide stable airflow rates that ensure reliability and adequacy to meet the minimum ventilation rates for building users in a controlled environment. Thus, a paradigm shift in the mechanical ventilation system is needed to steer the focus from the predominant energy efficient space-based design to occupant-based design. This study will discuss the cost-related effects to ensure stable and adequate ventilation by setting up ventilation scenarios with parameters derived from the recommendations published in recent guidelines focusing on HVAC operations. A working methodology is applied to a case study on two zones, an office, and a nursery. The results show that maintaining a minimum of five and seven air changes per hour for office and nursery, respectively, with proper indoor air distribution can reduce the risk of infection by more than half while ensuring an economic balance between ventilation costs and infection risk. Additionally, the study suggests using photovoltaics installations to power ventilation rates higher than five air changes per hour which can save at least forty-five tons of CO2 while reaching a payback period in thirteen years. Based on the achieved results, the paper presents recommendations to operate the two zones’ ventilation, space heating, and photovoltaics cost-effectively while ensuring COVID-19 probability of infection reduction.