Applicability of ASHRAE Standard 55 and EN 15251 Adaptive Thermal Comfort Models in Hot-and-Humid Climate

摘要

Background: The inclusion of adaptive thermal comfort model in the ASHRAE Standard 55 and EN 15251 exemplifies the increasing effort of improving indoor environmental quality in naturally ventilated buildings. However the applicability of these models in areas of hot-and-humid climate such as Taiwan has been only insufficiently validated. Aims: This study examined the boundaries of thermal comfort zones as predicted by the ASHRAE and EN models to those established by a field study conducted in Taiwan to examine the discrepancies between these models as well as between the model projection and field observation so to evaluate the models' local applicability. Methods: A field study was conducted to investigate the adaptive thermal comfort in 113 naturally ventilated classrooms of 14 schools in central Taiwan. For a.total period of five months consisting of summer, autumn and winter conditions, questionnaire survey were performed to observe the actual thermal sensation of the students in relation to the thermal status in the ambient environment when the school was in session. The observed thermal acceptability was analyzed against those projected by the ASHRAE and EN models using local meteorological data. Results: Both the ASHRAE and EN models significantly underestimated the thermal acceptability of Taiwanese when the ambient temperature fell outside the range of approximately 20 to 30oC. When the upper limit of the comfort zones projected by these models was compared, the predictability of the ASHRAE model appeared to be less than that of the EN model in the warm condition. The EN comfort zones Category Ⅰ and Ⅱ were more consistent to field observations than the ASHRAE comfort zones 90 and 80%. Conclusions: When applied to specific regions the ASHRAE and EN adaptive comfort models should be first assessed for applicability and calibrated to accommodate regional differences in climate and in patterns of thermal adaptation.