title: Effectiveness of photocatalytic filter for removing volatile organic compounds in the heating, ventilation, and air conditioning system.
abstract: Nowadays, the heating, ventilation, and air conditioning (HVAC) system has been an important facility for maintaining indoor air quality. However, the primary function of typical HVAC systems is to control the temperature and humidity of the supply air. Most indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical HVAC systems. Thus, some air handling units for removing VOCs should be added in typical HVAC systems. Among all of the air cleaning techniques used to remove indoor VOCs, photocatalytic oxidation is an attractive alternative technique for indoor air purification and deodorization. The objective of this research is to investigate the VOC removal efficiency of the photocatalytic filter in a HVAC system. Toluene and formaldehyde were chosen as the target pollutants. The experiments were conducted in a stainless steel chamber equipped with a simplified HVAC system. A mechanical filter coated with Degussa P25 titania photocatalyst and two commercial photocatalytic filters were used as the photocatalytic filters in this simplified HVAC system. The total air change rates were controlled at 0.5, 0.75, 1, 1.25, and 1.5 hr(-1), and the relative humidity (RH) was controlled at 30%, 50%, and 70%. The ultraviolet lamp used was a 4-W, ultraviolet-C (central wavelength at 254 nm) strip light bulb. The first-order decay constant of toluene and formaldehyde found in this study ranged from 0.381 to 1.01 hr(-1) under different total air change rates, from 0.34 to 0.433 hr(-1) under different RH, and from 0.381 to 0.433 hr(-1) for different photocatalytic filters.
authors.affiliation: Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Republic of China. f89541105@ntu.edu.tw
authors.forename: Kuo-Pin
authors.initials: KP
authors.lastname: Yu
authors.forename: Grace Whei-May
authors.initials: GW
authors.lastname: Lee
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Huang
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Wu
authors.forename: Chia-ling
authors.initials: CL
authors.lastname: Lou
authors.forename: Shinhao
authors.initials: S
authors.lastname: Yang
mesh_terms: D000389:Air Conditioning; D000393:Air Pollutants / Q000737:chemistry / Q000302:isolation & purification / Q000528:radiation effects; D016902:Air Pollution, Indoor / Q000032:analysis / Q000517:prevention & control*; D002384:Catalysis; D004784:Environmental Monitoring; D005374:Filtration / Q000379:methods; D005557:Formaldehyde / Q000737:chemistry / Q000302:isolation & purification* / Q000528:radiation effects; D006361:Heating; D006813:Humidity; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry; D014050:Toluene / Q000737:chemistry / Q000302:isolation & purification* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014691:Ventilation; D014835:Volatilization
chemical_list: D000393:Air Pollutants; C009495:titanium dioxide; D005557:Formaldehyde; D014050:Toluene; D014025:Titanium