AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Enhancement of Nanoparticle Removal for HVAC and Indoor Air Cleaner Filters by Adding Nanofibers
SHENG-CHIEH CHEN, Min Tang, David Y. H. Pui, University of Minnesota
Abstract Number: 450 Working Group: Control and Mitigation Technology
Abstract Pleated electret HVAC filters are often used in residence to mitigate the particles that originate both indoors and outdoors. However, there are two concerns about the performance of electret media: 1. low efficiency at particle diameter of 10-30 nm at initial filtration condition, which represent the MPPS (most penetrating particle size) and 2. significant efficiency reduction during the loading process. In this study, a filter media prototype composed of commercial HVAC electret media and nanofiber layer was proposed and tested. For the initial efficiency, it was found that the nanofiber layer of the composite media can increase the efficiency at the MPPS (20-30 nm) significantly. Besides, the new media made a fully use of both the mechanical force and electrostatic charge as it has good performance over the loading process as shown in the following. The loading performance of the new media was evaluated by polydisperse NaCl particles which mimicked the size distribution of typical atmospheric PM2.5. It was found that the efficiency only decreased 5.1, 11.0, 14.4, 11.6, 5.7 and 5.3% compared with the initial efficiency for particles with sizes of 50, 80, 100, 200, 300 and 500 nm respectively. This reduction due to the shielding of fiber charge was less than 1/3 in comparison with the solely electret layer without adding nanofibers. Surprisingly, the overall loading FOM (figure of merit) of the composite media was close to that of electret media, indicating there was a negligible trade off pressure increase by adding the nanofiber layer. In conclusion, this type of combination provided a unique structure to take advantage of electret media and nanofiber layer.