title: Selective permeation of moisture and VOCs through polymer membranes used in total heat exchangers for indoor air ventilation.
abstract: Fresh air ventilation is central to indoor environmental control. Total heat exchangers can be key equipment for energy conservation in ventilation. Membranes have been used for total heat exchangers for more than a decade. Much effort has been spent to achieve water vapor permeability of various membranes; however, relatively little attention has been paid to the selectivity of moisture compared with volatile organic compounds (VOCs) through such membranes. In this investigation, the most commonly used membranes, both hydrophilic and hydrophobic ones, are tested for their permeability for moisture and five VOCs (acetic acid, formaldehyde, acetaldehyde, toluene, and ethane). The selectivity of moisture vs. VOCs in these membranes is then evaluated. With a solution-diffusion model, the solubility and diffusivity of moisture and VOCs in these membranes are calculated. The resulting data could provide some reference for future material selection.
  
  
  CONCLUSIONS
  Total heat exchangers are important equipment for fresh air ventilation with energy conservation. However, their implications for indoor air quality in terms of volatile organic compound permeation have not been known. The data in this article help us to clarify the impacts on indoor VOC levels of membrane-based heat exchangers. Guidelines for material selection can be obtained for future use total heat exchangers for building ventilation.
authors.affiliation: Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Education Ministry, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, China. lzzhang@scut.edu.cn
authors.forename: L-Z
authors.initials: LZ
authors.lastname: Zhang
authors.forename: X-R
authors.initials: XR
authors.lastname: Zhang
authors.forename: Q-Z
authors.initials: QZ
authors.lastname: Miao
authors.forename: L-X
authors.initials: LX
authors.lastname: Pei
mesh_terms: D061808:Air Filters; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis; D006801:Humans; D006813:Humidity; D011108:Polymers; D013227:Steam / Q000032:analysis; D014691:Ventilation; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D011108:Polymers; D013227:Steam; D055549:Volatile Organic Compounds