| With the rapid development of economic and medical level,the urban aging has become more serious.The expanding populations of elderly people has led to insufficient outdoor environmental resources per capita.The contradiction between the quality of outdoor environmental and demand for the livable environment of the elderly has deepened.This phenomenon is even more pronounced in the severe cold northeast region of China.The residential environment and outdoor thermal comfort have significant impact on the quality of life and health of the elderly because of the severe climate,urban environmental problems,lower economic level and higher urban vulnerability.This paper aims to quantitatively analyze the outdoor thermal comfort of the elderly in residential areas in severe cold regions of China.According to the literature review,the evaluation index would be confirmed and an new evaluation framework would be created.By using the field research,questionnaire surveys,numerical simulations and machine learning methods,the thermal environment of urban residential areas and the subjective evaluation characteristics of outdoor thermal comfort of the elderly would be analyzed.Furthermore,the threshold range of the evaluation index of the elderly outdoor thermal comfort has revised and the outdoor thermal comfort model of the elderly in different seasons has established,which provide the guidance for urban high-quality residential environment areas and outdoor thermal comfort of the elderly in severe cold cities.Firstly,through a systematic review of outdoor thermal comfort evaluation indicators and the current research status of outdoor thermal comfort of the elderly,the suitable evaluation indicators for evaluating outdoor thermal comfort of elderly people in residential areas in severe cold areas has presented.Create the function and combined with deep learning algorithms,the framework of "on-site measurement--numerical simulation--coupling program--parameterized calculation" has built.And the various seasonal evaluation models to analyze the outdoor thermal comfort state of the elderly in residential areas in severe cold cities has constructed.Secondly,by analyzing the data of thermal environment,distribution characteristics and the subjective thermal sensation of the elderly in residential areas in different seasons,it is found that the measured points in the residential areas are different due to the various environmental composition and spatial feature.Even in the same season,there are also significant differences in thermal parameters.Besides,the air temperature is the most important factor closely related to outdoor thermal comfort that is generally considered by the elderly,followed by wind speed,and relative humidity is the lowest.It is found that the subjective outdoor thermal comfort of the elderly is highly correlated with wind speed and radiation temperature in winter and spring,and it is highly correlated with air temperature and radiation temperature in summer and autumn according to the regression analysis of subjective thermal sensation vote and different thermal environment parameters.Thirdly,this study revises the threshold range of the outdoor thermal comfort evaluation index for the elderly in residential areas in severe cold cities.Based on the measured data on site,the site model and numerical model with different inlet orientations in different seasons has established and modified.By using the mathematical software to write functions and call the Fluent model with the correct orientation to obtain the simulation values of air temperature and wind speed,establish the empirical regression equation to obtain the value of relative humidity at the questionnaire location;the value of evaluation index UTCI(Universal Thermal Climate Index)is calculated by Rhino-Grasshopper,and the correlation analysis with the subjective outdoor thermal sensation vote(TSV)of the elderly in the same location is calculated,it serves as a basis of threshold range of UTCI adaptation.The results showed that the UTCI value of neutral of the elderly is 3.4-21.4℃,which is lower than the basic reference value of UTCI(9-26℃)and the cold region of China(12-25℃).In addition,the range of the neutral value of the elderly is lower than the middle-young people in the same climate zone.Moreover,the cold sensation threshold of the elderly is slightly lower than that of the middle-young people due to the influence of factors such as the thermal resistance of clothing,thermal experience and thermal adaptation,but the hot sensation is relatively similar,with a difference of only 2.6°C.Finally,the outdoor thermal comfort model of the elderly in different seasons was built based on the artificial neural network.The annual air temperature,radiation temperature,wind speed and relative humidity would be obtained by using the meteorological model.Furthermore,the annual UTCI value would be calculated by Rhino-Grasshopper platform,which was the target data of the thermal comfort model.Besides,after regression analysis with the UTCI value and different meteorological index,the significance of factors were p<0.05 would be selected as the input data of the thermal comfort model.Hence,the outdoor thermal comfort model of the elderly in severe cold areas in each season were built separately after constructing,adjusting and training.The results found that the wind radian and cloud coverage have a low impact on UTCI in summer,all meteorological categories have a significant impact on UTCI in winter,and for the transition season,the relative humidity has low significance on UTCI.Furthermore,the study found that the accuracy of the summer model was the highest,while the winter was the lowest through the empirical analysis of thermal comfort model.The accuracy of the transitional season model for autumn is slightly higher than that of spring.This research provides significant research foundation and evaluation method for the healthy urban planning,design of residential environment and the improvement in outdoor thermal comfort of the elderly in severe cold regions. |
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