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Engineering Commons

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Materials Science and Engineering

Portland State University

Series

Air conditioning

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Engineering

Ozone Removal Efficiency And Surface Analysis Of Green And White Roof Hvac Filters, Omed A. Abbass, David Sailor, Elliott T. Gall May 2018

Ozone Removal Efficiency And Surface Analysis Of Green And White Roof Hvac Filters, Omed A. Abbass, David Sailor, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Heating, ventilation, and air-conditioning ( HVAC ) system filters from a commercial building were tested for their ability to remove ozone from intake air. Filters were taken from rooftop HVAC systems installed for two months: one located on a white membrane roof and the other on a vegetated green roof. One new, unused filter sample was tested as a reference. Samples from these filters were exposed to ozonated air streams at 40 and 120 ppb and relative humidity levels of 30% and 70%. Filter surfaces were analyzed with a scanning electron microscope to observe the structure and composition of the …


Bioaerosol Deposition On An Air-Conditioning Cooling Coil, Yan Wu, Ailu Chen, Irvan Luhung, Elliott T. Gall, Qingliang Cao, Victor Wei-Chung Chang, William W. Nazaroff Nov 2016

Bioaerosol Deposition On An Air-Conditioning Cooling Coil, Yan Wu, Ailu Chen, Irvan Luhung, Elliott T. Gall, Qingliang Cao, Victor Wei-Chung Chang, William W. Nazaroff

Mechanical and Materials Engineering Faculty Publications and Presentations

This study is concerned with the role of a fin-and-tube heat exchanger in modifying microbial indoor air quality. Specifically, depositional losses of ambient bioaerosols and particles onto dry (not cooled) and wet (cool) coil surfaces were measured for different airspeeds passing through the test coil. Total, bacterial and fungal DNA concentrations in condensate water produced by a wet coil were also quantified by means of fluorescent dsDNA-binding dye and qPCR assays. Results revealed that the deposition of bioaerosols and total particles is substantial on coil surfaces, especially when wet and cool. The average deposition fraction was 0.14 for total DNA, …