Li Bingxu, Cai Wenjian
School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
Energy Research Institute @ NTU (ERI@N), Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore.
Build Environ. 2022 Jul 1;219:109232. doi: 10.1016/j.buildenv.2022.109232. Epub 2022 May 26.
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 CO-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 CO 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 CO sensors and does not require occupancy detection sensors. Since CO sensors are very mature and low-cost, the proposed strategy is suitable for mass deployment in most existing ventilation systems.
通风对于在室内环境中控制新冠病毒传播至关重要。许多指南都建议将通风率保持在较高水平，以稀释携带病毒的呼吸道颗粒并降低空气传播风险。然而，高通风率会导致高能耗。需求控制通风是一种很有前景的技术选择，可实现以节能方式控制室内空气质量。本文提出一种基于一氧化碳的新型需求控制通风策略，以限制新冠病毒在室内环境中的传播。首先，建立了新冠病毒感染风险与一氧化碳平均水平之间的定量关系。然后，在对感染者数量进行保守考虑的情况下，提出了一个充分条件，以确保新冠病毒事件繁殖数小于1。最后，设计了一种通风控制方案，以确保上述条件能够得到满足。在一个实际通风系统的试验台上对不同室内环境进行了案例研究，以验证所提策略的有效性。结果表明，与固定通风方案相比，所提策略能够有效地将繁殖数维持在小于1的水平，以限制新冠病毒传播，同时节省约30%-50%的能源。与现有研究相比，所提策略具有更多实用价值：它适用于存在多个感染者且感染者数量随时间变化的场景；它只需要一氧化碳传感器，不需要占用检测传感器。由于一氧化碳传感器非常成熟且成本低廉，所提策略适合在大多数现有通风系统中大规模部署。
