Study On Operation Behavior And Performance Of Portable Air Cleaner In Residential Buildings Study On Operation Behavior And Performance Of Portable Air Cleaner In Residential Buildings

At present,the characteristics of indoor air pollution in China are the coexistence of PM2.5 pollution caused by outdoor sources and VOCs pollution caused by indoor sources.In response to the current situation of indoor pollution,more and more Chinese households are using portable air cleaner as a means of indoor air quality control.Numerous air cleaning technologies have been applied to air cleaners,but their effectiveness has not been fully verified.The existing research on the cleaning effect of air cleaner is mostly concentrated in the environment cabin,and its application at realistic indoor conditions is rarely published.In view of the above problems and shortcomings,this article has carried out a series of studies.The main conclusions are as follows:(1)The commonly used cleaning technologies in air cleaners are HEPA filtration and activated carbon adsorption,ionic,catalytic oxidation and electrostatic.The CADR of air cleaner for particulate matter ranged from 0 to 800 m3/h,and for formaldehyde ranged from 0 to 400 m3/h.The CADR ratio was mainly 2 to 4.The price of air cleaner is exponentially related to the CADR and the power and the noise is quadratically related to the CADR.(2)The popularity of air cleaners in China is about 5%,which is much lower than that in other developed countries.The operation rate of air cleaners is only about 20%.The average operating time was only about 1-4 h on the days they used the device,and usually ran at low and medium airflow mode.The operation mode of air cleaner is low frequency,intermittent and low air flow.With such operation behaviors,the air cleaner could not significantly improve the indoor air quality indicating by the PM2.5 concentration level,although the efficiency of the air cleaner is high enough to reduce the pollutant level if it is turned on.The I/O ratio was 0.36?1.31 when the air cleaning device was turned off,and was 0.23?0.77 when the device was turned on.In most cases,the effectiveness of air cleaner can reach the recommended value of 0.8,but when CADR is small,the effectiveness can be as low as 0.4(3)The operation probability of air cleaners of two households in Beijing obeys Gamma(0.46,0.102),the operation probability is about 0.37?0.59.The operation probability of air cleaners of two househ olds in Tianjin obeys LN(0.46,0.102),the operation probability is about 0.42?0.61.(4)For a single room,when the CADR per unit area is 5(m3/h)/m2,the difference between different measure points is 26%and the location of air cleaner is an important factor affecting the cleaning effect.When the CADR per unit area is 15(m3/h)/m2,the difference between different measure points is about 6%.It can almost ignore the effect of location on the cleaning effect.When the CADR per unit area is 30(m3/h)/m2,the difference between different measure points is less than 1%.The influence of different measure points on cleaning effect can be completely neglected.For multi-zone rooms,although air cleaner is often recommended to be used in closed rooms,the CADR value will decrease significantly,but it also has a certain cleaning effect on the whole room.