Assessment of COVID-19 infection Risk, thermal Comfort, and energy efficiency in negative pressure isolation wards with varied ventilation modes

Abstract

Negative pressure isolation wards (NPIWs) play a crucial role in providing care to COVID-19 patients during a pandemic. However, the exhalation of patients releases aerosols containing pathogens, posing a potential infection risk for healthcare workers (HCWs). While robust ventilation systems within NPIWs can help mitigate this risk, they may also lead to increased energy consumption and reduced thermal comfort for patients. Therefore, it is imperative to strike a delicate balance between HCW safety, patient comfort, and energy efficiency when optimizing airflow within NPIWs. This study introduces TARGETING, a novel index designed to assess the efficiency of aerosols removal of ventilation systems in NPIWs. The primary goal of TARGETING is to enhance the precision of ventilation systems, consequently reducing the required air changes per hour (ACH) and minimizing energy consumption. The research delves into the impact of various supply air parameters, including ACH and temperature, as well as different ventilation modes. Through a comprehensive evaluation utilizing an array of metrics such as the Air Diffusion Performance Index (ADPI), Predicted Mean Vote (PMV), TARGETING, infection risk assessment, and energy consumption estimation measured by cooling load (Lcool), this study employs an Analytic Hierarchy Process to assess the aforementioned indices. The findings highlight that air curtain ventilation (ACV) emerges as the most favorable choice, delivering comprehensive benefits, including an infection risk of less than 0.03%, an ADPI score of 90.2%, a PMV close to zero, TARGETING at 1.3, and energy savings ranging from 35.1% to 57.3%.