Study On Comfort Control Strategy Of Landing Fan In Heat Environment

In a heat environment,the cooling effect of the airflow can be exerted to meet the thermal comfort of the human body,thereby saving energy consumption of the air conditioning system.Appropriate air flow can effectively improve the thermal comfort of the human body from both psychological and physiological aspects,and the dynamic airflow can effectively alleviate the fatigue of the hair dryer.With the deep research on the influence of airflow on human thermal comfort,it is found that in addition to the airflow,the average velocity has a significant influence on the human body's thermal sensation.Other characteristic parameters of the airflow(such as the turbulence intensity of the airflow Tu,the airflow fluctuation frequency f,etc.)are on the human body.Thermal comfort also has an important impact.In this paper,the flow field of indoor natural wind,three-leaf fan,five-leaf fan and nine-leaf fan is sampled,and the characteristic parameters of typical indoor natural wind and mechanical wind are compared and analyzed(Skewness,Kurtosis,Turbulence,Power Spectrum Index ?).The typical manual laborers in Chongqing were selected as the representative population using the fan to conduct the human thermal comfort response experiment,and the comfort wind speed range of the subjects in the partial heat environment was obtained.The sine wave,pulse wave and random wave are selected to control the motor frequency.At the same time,the upper and lower limits of the three waveforms are controlled by the comfort interval,and the control strategy of the spectral eigenvalue ? greater than 1.1 is obtained by changing the fluctuation period.Firstly,the flow field characteristics of indoor natural wind are studied,and it is found that the variation of wind speed with time is irregular.The skewness value of indoor natural wind is greater than zero,showing a right skewness distribution,and the peak value oscillates around 3.The turbulence of indoor natural wind is concentrated between 0.3 and 0.4.The spectral characteristic beta values of natural wind are mainly between 1.2 and 1.6,which fully reflects the 1/f turbulence characteristics of natural wind.Secondly,the mechanical wind characteristics of three commonly used electric fans are studied.The mechanical wind has a skewness value less than zero,that is,a left skewed distribution.The turbulence Tu is related to the blowing distance.The farther the distance is,the larger the Tu value is.The energy distribution of the power spectrum function is not much different,and its ? value is less than 1.1.Then taking the typical hot and humid environment in summer in Chongqing as the background,taking the sitting level of typical manual workers in Chongqing as the research object,this paper explores the improvement efficiency of people's thermal comfort with different wind speeds when using common fans in hot and humid environment.Determined acceptable wind speeds for different temperature levels(28/30/32 ° C)and different relative humidity levels(50%,70%,90%)to determine acceptable temperatures for improved blow comfort at comfortable levels Humidity intervalFinally,the electric fan is modified to make the motor speed change according to the sine,pulse and random law,and the flow field characteristic parameters of different periods are obtained,and the cycle of the comfort electric fan closest to the natural wind is obtained.Cluster analysis of the flow field parameters of the three control strategies shows that the flow field parameters of the sinusoidal wind and the natural wind are the closest.