A novel CO2-based demand-controlled ventilation strategy to limit the spread of COVID-19 in the indoor environment. (1st July 2022)

• Record Type: Journal Article
• Authors: Li, Bingxu; Cai, Wenjian
• Is Part Of: Building and environment. Volume 219(2022)
• Publication Date: 2022-07-01
• Subjects: Demand-controlled ventilation -- COVID-19 -- CO2 concentration -- Event reproduction number -- Ventilation control scheme; Buildings -- Environmental engineering -- Periodicals; Building -- Research -- Periodicals; Constructions -- Technique de l'environnement -- Périodiques; Electronic journals; 696
• DOI: 10.1016/j.buildenv.2022.109232
• Languages: English
• ISSNs: 0360-1323

Abstract

Abstract: Ventilation is of critical importance to containing COVID-19 contagion in indoor environments. Keeping the ventilation rate at high level is recommended by many guidelines to dilute virus-laden respiratory particles and mitigate airborne transmission risk. However, high ventilation rate will cause high energy use. Demand-controlled ventilation is a promising technology option for controlling indoor air quality in an energy-efficient manner. This paper proposes a novel CO2 -based demand-controlled ventilation strategy to limit the spread of COVID-19 in indoor environments. First, the quantitative relationship is established between COVID-19 infection risk and average CO2 level. Then, a sufficient condition is proposed to ensure COVID-19 event reproduction number is less than 1 under a conservative consideration of the number of infectors. Finally, a ventilation control scheme is designed to make sure the above condition can be satisfied. Case studies of different indoor environments have been conducted on a testbed of a real ventilation system to validate the effectiveness of the proposed strategy. Results show that the proposed strategy can efficiently maintain the reproduction number less than 1 to limit COVID-19 contagion while saving about 30%–50% of energy compared with the fixed ventilation scheme. The proposed strategy offers more practical values compared with existing studies: it is applicable to scenarios where there are multiple infectors, and the number of infectors varies with time; it only requires CO2 sensors and does not require occupancy detection sensors. Since CO2 sensors are very mature and low-cost, the proposed strategy is suitable for mass deployment in most existing ventilation systems. Highlights : A CO2 -based DCV strategy is proposed to limit the spread of COVID-19. Quantitative relationship is established between infection risk and CO2 level. A sufficient condition is proposed to ensure the reproduction number less than 1. This strategy can achieve safe and energy-efficient control of infection risk.