Abstract
This study experimentally evaluates the performance of a two-stage indoor air filtration system with the focus on main-stage filter media selection. The impact of the main-stage filter media properties on the effectiveness of adding a pre-stage filter media is compared among three main-stage filter media types commonly used in heating, ventilation, and air conditioning (HVAC) filtration system: cellulose, melt-blown, and expanded PTFE membrane. The pre-stage filter media effectiveness was found to be significantly affected by the incoming aerosol size distribution. Although counter-intuitive, having an additional pre-stage filter was found to cause a service lifetime drop for cellulose-type main-stage filters depending on incoming aerosol size distribution, while universally enhanced life spans were found for melt-blown and PTFE membrane-coated main-stage filters. The mechanism that causes a shortened service life of cellulose main-stage filter with the presence of a pre-stage filter was explored in detail and was found to be associated with the special particle loading behavior of conventional cellulose media. The rapid pressure drop increase of cellulose media in depth and transitional filtration regimes was strongly affected by the incoming aerosol size distribution, with a steeper slope (faster pressure drop increase) associated with finer particles penetrating more deeply into the inhomogeneous pores of cellulose media. The pre-stage filter alters the particle size distribution of the main-stage faces, with an increased fraction of fine particles that negatively impacts the main-stage filter loading behavior. This observation and mechanism analysis are the first time being reported, which suggests a careful selection of the combination of pre-stage and main-stage filter types with the consideration of incoming contaminant properties. It is essential for researchers and engineers in designing energy-efficient two-stage filtration systems.
| Original language | English (US) |
|---|---|
| Article number | 107745 |
| Journal | Building and Environment |
| Volume | 195 |
| DOIs | |
| State | Published - May 15 2021 |
Bibliographical note
Funding Information:The authors thank the support of the National Science and Technology Major Project of China (Award ID: 2017YFC0211801 ). And thank to the National Science and Technology Major Project of Liaoning Province (Award ID: 2019JH2/10100004 ).
Funding Information:
The authors thank the support of members of the Center for Filtration Research: 3 M Corporation, A.O. Smith Company, Applied Materials, Inc. BASF Corporation, Boeing Company, Corning Co. China Yancheng Environmental Protection Science and Technology City, Cummins Filtration Inc. Donaldson Company, Inc. Entegris, Inc. Ford Motor Company, Guangxi WatYuan Filtration System Co. Ltd, LG Electronics Inc. Mott Corporation, MSP Corporation; Parker Hannifin, SamsungElectronics Co. Ltd. Xinxiang Shengda Filtration Technology Co. Ltd. TSI Inc. W. L. Gore & Associates, Inc. Shigematsu Works Co. Ltd. and the affiliate member National Institute for Occupational Safety and Health (NIOSH). The authors thank the support of the National Science and Technology Major Project of China (Award ID: 2017YFC0211801). And thank to the National Science and Technology Major Project of Liaoning Province (Award ID: 2019JH2/10100004). The author also received financial aid from the project of China Scholarship Council. Parts of this work were carried out in the Characterization Facility, the University of Minnesota, a member of the NSF-funded Materials Research Facilities Network (www.mrfn.org) via the MRSEC program.
Funding Information:
The author also received financial aid from the project of China Scholarship Council.
Publisher Copyright:
© 2021
Keywords
- Depth filtration
- Dust holding capacity
- Main-stage filter
- Pre-stage filter
- Surface filtration
