Environmental Comfort On The Square Based On Combined Thermal-acoustic Effects

As an important public space in the city,the square is the primary place for urban residents to perform leisure activities.Its environmental quality is of great significance to enhance the vitality of urban space.However,due to the lack of consideration for environmental quality,especially the physical environment,most city squares have specific environmental problems.Due to the influence of climatic conditions and design concepts,the issues of the thermal-acoustic environment on the square in the severe cold cities are relatively serious and have seasonal variation.At the same time,although the researches on the quality of the thermal-acoustic environment or environmental perceptions on the square are extensive,there are few studies on the correlation between the objective environmental quality and the subjective perception evaluation of users in the squares.Although the researches on the influence of a single factor and its different levels on environmental perception are in-depth,the investigations on the combined effects of multiple factors,especially their interactions,are still scarce.Therefore,based on the demands for improvement of the thermal-acoustic environment on the squares in severe cold cities and the limitations of related researches,taking the small and medium-sized leisure squares in Harbin as an example,this study adopts the method which is the combination of subjective and objective as well as multidisciplinary integration,in order to comprehensively evaluate the objective environmental quality on the squares from the perspective of users' subjective perception.The results can provide references for the design,environmental construction and improvement of urban square space.This study adopts comprehensive research methods including field measurement,environmental chamber experiment,questionnaire survey,statistical analysis,numerical simulation to evaluate the environmental comfort level on the square.The spatial morphological characteristics and the thermal-acoustic environment of leisure squares,small and medium-sized,are systematically analysed in Harbin in different seasons(winter,transition seasons and summer).The influences of combined thermal-acoustic effects on the subjective perception of the square in different seasons are profoundly distinguished.The equivalent intervals and evaluation models of comfort level based on combined thermal-acoustic effects are constructed.Through the comprehensive evaluations of the environmental comfort on the squares,the square space form with better adaptability to year around thermal-acoustic environment is explored.First of all,the influence of square spatial form on the thermal-acoustic environment is revealed.Based on the statistical data of the morphological control elements,the main spatial morphological elements such as block orientation,surrounding road conditions,surrounding building heights,plane scales are extracted through satellite imagery and field survey.Square models with different spatial forms are constructed through orthogonal experiment design.Current conditions and differences in the thermal-acoustic environment of the squares in different seasons are explored through field measurement.The thermal-acoustic environment quality of square models throughout the year is simulated and calculated,and the differences in the thermal-acoustic environment of the square with different spatial forms are explored.The results provide objective environmental data to evaluate the environmental comfort level on the squares.Secondly,the study on the influence mechanism of combined thermal-acoustic effects on environmental perception is carried out.Actual outdoor temperature conditions in different seasons are simulated in the controllable environment chamber,and questionnaire surveys are conducted.The influences of various square sound sources and typical seasonal temperatures on the acoustic environmental perception,thermal environmental perception and overall perception evaluations are analysed under the combined thermal-acoustic effects.It provides essential data and screens suitable sound source for field study in the square.Furthermore,universal thermal climate index and A-weighted equivalent continuous sound level are selected as environmental parameter indicators.The influences of different levels of temperature and traffic sound on the dynamic environmental perception in the square are explored under combined thermal-acoustic effects in different seasons.The results provide subjective evaluation data basis to the construction of the evaluation models of comfort level.Finally,the environmental comfort level on the square is comprehensively evaluated based on the combined thermal-acoustic effects.The overall comfort is selected as the evaluation index.And the quantified relationship between the parameters of the objective thermal-acoustic environment and the subjective comfort level is analysed.Based on the combined thermal-acoustic effects,equivalent interval and evaluation models of comfort level are respectively calculated and established.The simulation data of the thermal-acoustic environment is used to calculate the environmental comfort level of the square models.Visual distribution map and statistical indicators such as mean value,extreme value,range,area ratio are used to evaluate the environmental comfort on the square comprehensively.The innovative result of this study is revealing the influence mechanism of combined thermal-acoustic effects on the subjective environmental perception of the square,including the influence of sound sources and typical seasonal temperatures,levels of temperatures and traffic sound in different seasons.This study also explores the quantitative relationship between objective thermal-acoustic environmental parameters and subjective perceptions.Evaluation models of comfort level based on the combined thermal-acoustic effects are constructed and applied to evaluate the environmental quality on the square comprehensively.This study establishes linkages between the objective environmental quality on the square and the user's subjective perception evaluation,which aligns with the development needs of urban construction in China.It has significant value and scientific significance for improving the urban environment and spatial vitality and the development of urbanization focusing on spatial quality.