Long-term perceptions of outdoor thermal environments in an elementary school in a hot-humid climate.

Previous studies on thermal comfort in school environments have focused more on indoor thermal environments than outdoor ones, thus providing a limited understanding of occupants' long-term thermal perceptions. Taiwan is located in a subtropical region, where it can be stiflingly hot outside in summer. This highlights the need to ensure proper thermal comfort on campus. In the present study, thermal environment parameters were measured and collected in several outdoor spaces of an elementary school in southern Taiwan. In addition, a questionnaire was used to explore occupants' long-term thermal perceptions of these spaces. During summer months, the physiological equivalent temperature (PET) of these outdoor spaces in over 60% of the daytime in summer between 10 a.m. and 4 p.m. was higher than 38 °C PET, indicating high heat stress. The results of occupants' long-term perceptions of the thermal comfort of these spaces suggested that dissatisfaction with thermal comfort was associated more with solar radiation than with wind speed. Finally, this study simulated a campus environment where more trees are planted and compared the thermal comfort indices before and after the simulation. The results indicated that this solution contributed to a decrease in the PET of these environments, thereby alleviating high heat stress. This study can inform the improvement of microclimates and thermal comfort during campus layout planning. Planting trees judiciously across a campus increases outdoor shades and creates outdoor spaces that are more comfortable and adaptable to hot weather conditions, thereby ensuring frequent use of these spaces.

Effect of fee-for-service air-conditioning management in balancing thermal comfort and energy usage.

Balancing thermal comfort with the requirement of energy conservation presents a challenge in hot and humid areas where air-conditioning (AC) is frequently used in cooling indoor air. A field survey was conducted in Taiwan to demonstrate the adaptive behaviors of occupants in relation to the use of fans and AC in a school building employing mixed-mode ventilation where AC use was managed under a fee-for-service mechanism. The patterns of using windows, fans, and AC as well as the perceptions of students toward the thermal environment were examined. The results of thermal perception evaluation in relation to the indoor thermal conditions were compared to the levels of thermal comfort predicted by the adaptive models described in the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard 55 and EN 15251 and to that of a local model for evaluating thermal adaption in naturally ventilated buildings. A thermal comfort-driven adaptive behavior model was established to illustrate the probability of fans/AC use at specific temperature and compared to the temperature threshold approach to illustrate the potential energy saving the fee-for-service mechanism provided. The findings of this study may be applied as a reference for regulating the operation of AC in school buildings of subtropical regions.