Thermal sensation and percentage of dissatisfied in thermal environments with positive and negative vertical air temperature differences

作     者：Yuxin Wu Sheng Zhang Hong Liu Yong Cheng 

作者机构：School of Civil Engineering and ArchitectureZhejiang Sci-Tech UniversityHangzhouZhejiang 310018China Joint International Research Laboratory of Green Buildings and Built Environments(Ministry of Education)Chongqing UniversityChongqing 400045China School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’an 710049China School of Civil EngineeringChongqing UniversityChongqing 400045China 

出 版 物：《Energy and Built Environment》 (能源与人工环境(英文))

年 卷 期：2023年第4卷第6期

页      面：629-638页

核心收录：

学科分类：080701[工学-工程热物理] 08[工学] 0807[工学-动力工程及工程热物理] 0814[工学-土木工程] 

基　　金：The work presented in this paper is financially supported by the Fundamental Research Funds for the Central Universities(Grant No.2019CDYGYB026)。 

主　　题：Vertical air temperature difference Thermal sensation Thermal comfort Percentage of dissatisfied Air distribution 

摘      要：Considering the percentage of dissatisfied due to local thermal sensation(PD LTSV),a vertical air temperature difference(ΔT_(d))threshold of about 3°C was recommended in standards.However,some novel air distribution methods might create large positive(which means the head warmer than the feet,vice versa)or negativeΔT_(d),with no suitable proved criteria to be used.In this study,sixteen subjects were seated in a climatic box placed in a climate chamber to evaluate thermal sensation and percentage of dissatisfied with negative and positiveΔT_(d) in different whole-body thermal conditions.Air temperatures were controlled independently at the upper and lower body parts,with 13 different air temperature sets combined with 22°C,25°C,28°C,and 31°C(i.e.-9°C≤ΔT_(d)≤9°C).Results showed that subjects were more thermally sensitive at the upper body and with positiveΔT_(d) than at the lower body or with negativeΔT_(d).The 80%acceptableΔT_(d) range is about-8 to 7°C in overall neutral(TSV=0),-7°C to 6°C in slightly cool(TSV=-0.5)conditions,which is wider than-3 to 3°C in slightly warm conditions(TSV=+0.5).By considering the factors of both TSV andΔT_(d),a new overall percentage of dissatisfied index(OPD P)was proposed.Case studies show that the new OPD P index is more precise and suitable for the evaluations of different air distributions to predict overall percentage of dissatisfied in thermal environments with vertical air temperature difference.