Evaluation of Test Method of Indoor Air Cleaners
Date Issued
2006
Date
2006
Author(s)
Hou, Kuan-Ting
DOI
zh-TW
Abstract
Indoor air cleaners are commonly used as an adjunct to source control and ventilation. In ANSI/AHAM AC-1-2006 (Method for Measuring Performance of Portable Household Electric Room Air Cleaners), Clean Air Delivery Rate (CADR) is a measure of the appliance’s ability to reduce aerosol particles in the 0.10 to 11 μm size range. In the present study, the effects of test chamber size, aerosol size (distribution), aerosol number concentration, position and flow rate of aerosol spectrometer, and leak rate of the test chamber on the CADR measurements were investigated. Two types (ESP and filter) of commercially available indoor air cleaners were tested in a standard certification chamber, and a chamber only 1/8 of the volume. Polydisperse aerosol particles were generated using a constant output aerosol generator and an ultrasonic atomizer. Aerosol outputs from both generators were then neutralized by using a radioactive source (Kr-85) to neutralize the aerosol particle to the Boltzmann charge equilibrium. The main aerosol size-spectrometers were a Scanning Mobility Particle Sizer and an Aerodynamic Particle. The background decay rates were measured by using real time aerosol instruments and a Mini Infra-Red Analyzer (MIRAN) was used when SF6 was the test agent.
The results showed that CADR value is a function of aerosol size. The ESP- and filter-type air cleaners had significantly different characteristic CADR curves. In general, ESP air cleaner performed better in aerosol collection, air resistance, and power usage. The relative location and orientation of the air cleaner and aerosol spectrometer in the test chamber had almost no effect on the CADR measurements. The measured CADR values decreased with increasing aerosol number concentration apparently due to coagulation effect during the natural decay measurement. The coagulation effect became less significant if aerosol number concentration was lower than 1.0×105 #/cm3. Use of smaller test chamber is possible. However, only the data collected before infiltrated aerosols became significant should be used for calculating the CADR value. Room air cleaners with multi-level performance fan settings normally delivered higher CADR when operated under higher air cleaning mode setting, but not necessary the CADR/watt value, probably due to the difference in fan performance curve.
Subjects
空氣清淨機
室內空氣品質
CADR
Air cleaners
Indoor air quality
Type
thesis
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