Study On The Purification Of PM2.5Based On Air Conditioning Device Of Fan Coil In Office Environment

Indoor air quality imposes great influence on people’ health.The experiments conducted by theforeign experts in1990s showed that indoor particulate matter is a significant contributor to sickbuliding syndrome(SBS).Nowadays,indoor air pollution and its effect on peoples’ health havearoused universal attention.The conventional design of comfort HVAC system gives priority to theconditioning treatment,air-flow origination and building energy conservation rather than the dustconcentration.Out of consideration for the expense and convenience,compared with the strategy ofreplacing the existing HVAC system,install appropriate air filters in the return air inlet to improve thepartial indoor air quality appears to be an economical and reasonable solution.Therefore, PM2.5purification technology and air filtration device used in office building with common airconditioning system (fan coil system) is studied in this paper.In order to understand the use environment of filters,through the data of official and fieldmeasurement, variation of outdoor and indoor particle concentration was researched.Theresults show that, the air quality of Shanghai tends to improve since2008.Also concentration ofindoor particulate is susceptible influenced by cleaning, smoking, air-conditioning and other factors,and basically has nothing to do with printers and computers.The filtration properties and dust holding capacity of common air filter material and electret airfiltration material were contrasted and analysised.With low resistance, high efficiency as the mainindicators of the preliminary screening filteris which suitable for the airconditioning filter system.The results show that, electret air filtration performance is far superior tothe common air filtration materials,when take the quality factor and the dust containing capacity inconsidering.Study on the air filter mainly concentrated on the filter resistance which is closely related withthe air conditioning energy consumption.Establishing the mathematical model, and dividing the airfilter resistance into filter resistance, resistance to the import and export of local resistance and frictional resistance.Verified by theoretical analysis and experimental data, calculation formulaof filter resistance is derived for the pre-selection and design of filters.Based on the study of main filtration characteristics of the filter material and air filter, filtrationefficiency of fan coil of PM2.5and PM2.5concentration with time attenuation was measured underthe different indoor and outdoor particle concentration and different air speed conditions throughfield test method in a typical office as a case.Results show that, with decreasing air volume,theinfluence of measuring point position to PM2.5purification effect is gradually weakened, while theinfluence of outdoor ambient concentrations to measured PM2.5purification effect is graduallyincreased.With a test point, PM2.5purification effect increases with the amount of the wind and thefilter area increases, and almostly does not matter with the original indoor concentration.