| In recent years, air-conditioning has been widely used in our daily life in order to improve our living condition. With the changing of people's lifeway and working style, people pay more attention to the problem of indoor air quality. So the nation has come on a series of related standard to ensure the air quality in public places. The national code for design of heating, ventilation and air conditioning (GB50019-2003) and the first Indoor Environment Quality Standard in china, which has been constituted by National quality surveillance examine and quarantining Bureau, National Environment Bureau and Department of Public Health, set a request for the value of particles in the indoor air, that is, the average value per day should be equal to or less than 0.15mg/m3. It suggests that the air conditioning system is switching from comfort-oriented to comfort and purification-oriented, which brings new challenges and opportunities to the control of particles in civil air conditioning system.A direct and feasible way to remove the particle contaminants is to use filtration devices to filter indoor and outdoor air. However in China at present, filtration of the air conditioning systems in commercial buildings is generally at low efficiency or there is no filter at all. In order to meet the demands of paniculate matter in the comfort and purification-oriented air conditioning systems, much work , the testing and evaluation, the design and choosing of the filtration devices, needs to be done. This paper will provide a research concerning this subject.Our research begins with a testing of IAQ in ten department stores and a survey of the working staff in the stores, the survey confirmed that the IAQ can't meet the standard in ASHARE. The result suggests that IAQ can hardly reach the request set in Indoor Environment Quality Standard. For diluting the concentration of CO2, we introduce more flash air which will bring more particulate matter at the same time. And this will put forward higher demand to the filter devices.In order to study the performance of the commonly used bag-type filter, the author designed a testing set according to the National Standard (GB 12218-89), which can test the efficiency,resistance, dust holding capacity of the filter. In the formula Δp = Cvm, which is used tocalculate the resistance, the coefficient C is 0.000020.0035 and coefficient m is 1.12327 1.78358. The efficiency of the filter made by ordinary material goes up with the increase of the dimension of particulate matter and accumulating dust quantity on the material. The more dust amount that the filter can hold is, the longer service life is.For analyzing the stability of performance, the filter was washed by electrostatic discharge. After washing, The efficiency of the filter C has reduced to 87.6% with the ventilation amount of 3400m3/h and reduced to 90.5% with the ventilation amount of 1800m3/h. But resistance has not obviously changed.In order to know about the relation between the indoor particle's concentration and time, the author educed a formula that shows the indoor particle's instantaneous concentration based onindoor purifying model., analyzed the relations between the indoor particle's concentration changing and some factors including the indoor particle's initialization concentration, outdoor particle's concentration, the amount of flash air, the efficiency of the filter in the air conditioning systems.This research makes systematic analysis on the property of filtration devices in AC systems from both experimental and theoretical aspects. There is applied meaning and social value in solving the existing problem of construction environmental air quality and the protection of public health.Yu Xia (Heating, Ventilation, and Air Conditioning Engineering)Supervised by Prof. Shen Henggen... |
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