| As the development of industry, air pollution is becoming more and more serious. The particulate suspends in the air not only affects the visibility, but also will cause harm to human body health. Therefore, the fine particulate matter(PM2.5) has acquired wide concern since 2011, the year which hazy weather occurred frequently in mid-east region of China. Because of the small particulate size, PM2.5 can suspend in the atmosphere for a long time. And it always carries a lot of toxic substances which bring adverse influence on ambient air and human health.For buildings equipped with central air conditioning ventilation system, the fresh air must be handled by the HVAC systems before sent into indoor environment. To control PM2.5 from the resource and decrease indoor PM2.5 concentration, the filtration performance of different filters were studied. On the foundation of this, the suitable filter combination plan was put forward according to the various PM2.5 pollution situation in different areas. Comprehensive assessment of filter combination was investigation. The study results can provide a reference for the design and selection of fresh air handling units.In this research, the mechanism and characteristics of air filters are elaborated firstly, and the influencing factors are analyzed. Then based on the requirement of relevant standards, fresh air handling unit filter performance test platform is designed and established. The single filter filtration efficiency and pressure are tested, and air flow-resistance curves are drawn. The results show that the counting efficiency is slightly bigger than the weight efficiency on the condition of this experiment. Using weight efficiency is advised when doing selection calculation.Then according to the results of single filter experiment, combination schemes are designed and tested. Three stage filtration can be considered when two stage filtration cannot meet the control requirement. On the foundation of this, the relative lifetime of different filters in the units are calculated.At last, considering various PM2.5 pollution situation in different, a specific example is given. Different schemes should be assessed considering efficiency, resistance, lifetime and cost in practical applications, and the best option is determined ultimately.This study elaborates air filters characteristic indexes and influence factors based on the filtration mechanism. Experiment research about filters filtration for PM2.5 has been done with the test platform. The counting and weight efficiency of different filters are tested which provide essential data for analyzing the relationship between them. Then assessment indexes of different schemes are investigated. And the results can provide reference for the design of fresh air handling unit, which have practical value. |
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