Analysis Of Thermal Environment And Optimization Of Airflow Organization Strategy In College Classrooms In Northwest Sichuan

The health,comfort and energy saving of indoor thermal environment have always been the focus of attention of scholars.The evaluation of indoor thermal environment can be divided into objective evaluation and subjective evaluation,in which the objective evaluation are quantified by instrument,while the subjective evaluation focuses more on the physical and psychological feelings of human body,while there are often individual or group differences in the subjective feelings.Therefore,it is necessary to carry out in-depth investigation and Research on the thermal environment under certain conditions.In recent years,the number of undergraduate groups of China has increased rapidly,and their environmental health and comfort have been paid more and more attention by the state.This paper takes a classroom in a university in Northwest Sichuan as the research object,analyses the current situation of classroom thermal environment by means of questionnaires and field measurements,obtains the thermal comfort zones and attention concentration zone of undergraduate groups of this area,takes this as constraints,and compares and analyses the air distribution and energy-saving effects of three air distribution schemes: split air conditioning,upward and backward air distribution and wall-mounted jet by means of numerical simulation.The main research contents are as follows:1、Preliminary data collection.To find the breakthrough point of this subject,the research status of thermal environment in university classroom by domestic and foreign scholars is analyzed.According to the climatic characteristics of Northwest Sichuan,the universities with the largest number of students are selected as the preferred conditions,and the classroom with the highest frequency of use is selected as the research object.Typical days mainly consider the most unfavorable weather in summer,as well as sunny,cloudy and rainy days.2、Collection,sorting and analysis of survey and measured data.The basic data of classroom thermal environment and weather are acquired by means of on-site measurement and questionnaire survey.After sorting out the data,partial correlation analysis is carried out on thermal feeling,attention and mental state with SPSS software,and the range of air parameters of comfort zone and attention concentration zone of college students in Northwest Sichuan is determined.3 、 Numerical simulation,air flow optimization and energy saving.Taking comfort zone and concentration zone of undergraduates as constraints,three air distribution modes,i.e.split air conditioning,up-and-down air supply and wall-attached air jet,are simulated by Airpak software.The influence laws and energy-saving effects of different air-conditioning air supply on indoor air flow field are compared and analyzed,and a reasonable air-conditioning air supply scheme for classroom in this area is obtained.The results show that the temperature range of thermal comfort for undergraduates is slightly lower than the recommended value of ASHRAE,with23.07 ～25.40℃ and 45%-65% relative humidity.The temperature range of the focus area is 22.56 ～25.9℃ and the relative humidity is 45%-55%.It is suggested that the design parameters of university classroom should be taken as the intersection of the two values,i.e.the design values of temperature range from 23.07℃ to 25.40℃ and the design values of relative humidity range from 45% to 55%.The distribution of indoor air with jet air conditioning attached to the wall is better than that of split air conditioning and upward and backward centralized air conditioning currently used.The average air age is about 284 s,the coefficient of temperature non-uniformity is about 0.014,the coefficient of speed non-uniformity is about 0.377,the ADPI value is about 100%,and energy saving is 29.15% compared with upward and backward centralized air conditioning.