JAILCD2026-013: Study on Summer Thermal Preference of Temperate Region in Air-Conditioned Rooms

Abstract

In recent years, there has been a strong demand for indoor environmental planning that enables optimal energy use while maintaining occupants’ thermal comfort. To achieve this, it is necessary to use objective evaluation indices that can accurately assess occupants’ thermal sensations. However, there are discrepancies between conventional objective indices and subjective results. Therefore, it is essential to quantitatively clarify the relationship between the two to evaluate occupants’ thermal comfort as a design target in environmental planning. Based on the background, this study aims to assess the relationship between PMV (predicted mean vote) and TSV (thermal sensation votes) in air-conditioned settings in temperate climate zones. In the summer of 2025, at Mie University, Tsu City, Japan, we conducted experiments in an air-conditioned laboratory. Respondents gave a total of 264 answers. This study showed that, for adults staying under air-conditioned conditions without adaptive behaviors, their thermal sensations can be predicted using the conventional evaluation index PMV. According to respondents' Thermal Sensation Votes, the operative temperature range for comfort was 24.5°C to 27.2°C. All participants preferred 24.8°C, indicating a small preference for cooler conditions within the defined range. meanwhile at a 10% dissatisfaction level, PD (percentage dissatisfied) is comfortable at 25.1°C to 26.3°C, and at 20%, 23.4°C to 28.0°C. These findings provide new insights into thermal comfort evaluation in temperate regions. This study was limited to summer season and further study is needed in other seasons.