Influence of mechanical ventilation system on indoor carbon dioxide and particulate matter concentration

Conson K H Yu; Min Li; Vincent Chan; Alvin C K Lai

doi:10.1016/j.buildenv.2014.03.004

Influence of mechanical ventilation system on indoor carbon dioxide and particulate matter concentration

Build Environ. 2014 Jun:76:73-80. doi: 10.1016/j.buildenv.2014.03.004. Epub 2014 Mar 13.

Authors

Conson K H Yu¹, Min Li², Vincent Chan³, Alvin C K Lai¹

Affiliations

¹ Department of Civil and Architectural Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
² School of Energy Science and Engineering, Central South University, Changsha 410083, China.
³ School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 639798, Singapore.

Abstract

Common ventilation strategies may fail to maintain indoor air quality when atmosphere is heavily polluted by particulate matter. This paper evaluates the performances of common constant air volume (CAV) system and variable air volume (VAV) system when carbon dioxide and particles are significantly present in outdoor environment. Major system parameters including filter efficiency, occupancy number, ventilation air rate, and outdoor particle concentration are thoroughly examined. Firstly, a full-scale chamber experiment is performed to investigate the dynamics of CO₂ and airborne particles under steady and non-steady scenarios. The result is further validated with a previously-developed state-space model. Secondly, an exhaustive case study is conducted using an established mathematical model. In order to reduce CO₂ concentration, both CAV and CO₂-based demand-controlled VAV may cause an undesirable increase in particle concentration when outdoor air is heavily polluted by particles. This dilemma requires further studies on the optimization of ventilation schemes.

Keywords: CO2-based demand-controlled; IAQ; Particulate matter; State-space model; Ventilation.