Improvement of particle clean air delivery rate of an ion spray electrostatic air cleaner with zero-ozone based on diffusion charging

Abstract

A novel electrostatic precipitation type air cleaner with ion spray to indoor for diffusion charging was developed. To minimize unexpected collection of charged particles on wall or residents and to apply the ESP for real environment, the clean air delivery rate of the novel air cleaner was enhanced by increasing flow rate, collection area at the applied high voltages of -5 kV while its noise and ozone emission were evaluated. For practical usage, the CADR in real environment with 83.5 m3 was evaluated, and recovery tests after contamination of dusts and cleaning were performed. The experimental results show that with the flow rate increase to 10 m3/min and collection area increase to 4 m2, the particle CADR of 0.3-μm particles by the advanced ESP air cleaner increased to 7.32 m3/min which meant the air cleaning rate became faster approximate 8.5 times than that in our previous study, and 90% of the charged submicron particles were collected in the ESP within 16 min while emitting negligible ozone of 1.3 ppb for 12 h. In the real environment (83.50 m2), the particle CADRs were maintained within 15% of decrease, compared to those for the chamber test. Finally, particle collection performance was reduced over long-term operation, but almost recovered through cleaning processes. It is concluded that the ion spray ESP can be a proto indoor and electrostatic collection with frequent air circulation through it could be a promising air cleaning method without ozone emission for indoor air quality against fine particles.