JAUE2024-078: A Study on Short-term Thermal Adaptation Based on Occupancy Duration of Occupants

Abstract

In indoor environments, thermal comfort refers to a state of being thermally comfortable for occupants. The thermal comfort of occupants varies according to their thermal adaptation and adaptive behaviors. The approach that considers occupants' thermal comfort when determining thermal conditions is known as "adaptive thermal comfort". The time scale related to thermal adaptation can be categorized into short-term and long-term. This study focuses on short-term adaptation at an hourly scale, aiming to analyze the differences in thermal comfort due to variations in occupancy duration within a day. During the summer of 2024, a survey was conducted on occupants in a large indoor space to assess their occupancy duration and thermal comfort. The participants were dressed in attire similar to the ASHRAE summer standard and had metabolic rates equivalent to stting or standing. The analysis revealed that short-term thermal adaptation leads to differences in thermal sensation at the same indoor temperature depending on the occupancy duration. Additionally, the impact of occupancy duration varied with indoor temperatures (e.g., 25°C and 29°C). The findings of this study could be considered in designing air conditioning and ventilation strategies in large, unpartitioned indoor spaces, such as museums and exhibition halls, to ensure individual thermal comfort.