A Field Study Of Thermal Comfort In A Centrally Air-conditioned Office In Changsha,china

The Compressor cooling and heating become a major contributor to total energy consumption in southern China,where summer is long and humid and winter is cold.Majority thermal comfort studies in south China have been in naturally ventilated buildings,relatively less were in air conditioned buildings.In this study we aimed to investigate thermal comfort and adaptive behaviour in a centrally air conditioned office in Changsha,a typical city in hot-humid area in China.Longitudinal surveys were conducted in a centrally conditioned office from June 2016 to November 2017.Eighty-nine occupants participated in the study,they were instructed to answer comfort survey three times a day via a web-based survey system.Thermal environment(air temperature,globe temperature,relative humidity,air speed)and were measured continuously by data loggers.Overall a total of 3235 individual responses were collected.Occupancy was recorded via pressure sensor,actions on windows were recorded via magnetic switch recorder and actions on personal fans were recorded via power monitoring socket.Firstly,the voting of comfort survey in different seasons were analyzed.Results show that the predicted neutral temperature was close to the measured neutral temperature,but the slope to the TSV with the operating temperature was less than that of PMV,which indicates that the occupants of air-conditioned office in Changsha had a certain adaptability to the local environment.The 80 % upper acceptable temperature limit were 26.9 ?,and the 90 % acceptable temperature range was 20.1 ? to 24.8 ?,and the expected temperature was 23.8 ?.Secondly,analysis of the adaptive behavior of occupants show that the adjustment of personal clothing in air-conditioned office was restrained,the actions on windows and individual fans show the similarity to the rules of staff commuting.And the mathematical relations between the adaptive behavior and temperature was obtained.Finally,the findings of this study were compared with the relevant standareds and results found in the field studys on other similar climate,and the gender differences were analyzed.The results show that ASHRAE 55 standared has a deviation in evaluating the indoor environment of centrally air-conditioned offices,which 94.7 % of occupants were outside the 0.5 clo comfort zone in summer and 31.8 % of occupants were outside the 1.0 clo comfort zone.And the neutral temperature and adaotive behavior were different from the findings of natural ventilation buildings in this area.There was a certain difference of expectation of temperature and air speed between male and female,and the usage of personal fans was greater than that of female.The data collected in the field study of the centrally air-conditioned office in Changsha and conclusions can be used to guide future indoor thermal environmental design in south China.