A VR-treadmill-EEG laboratory method for studying effects of human activity states on thermal comfort in different types of large-scale public buildings

Thermal comfort is essential to the operational quality of large-scale public buildings. It is necessary to investigate how occupant activities affect thermal comfort in different types of large-scale public buildings. This study utilized a VR–treadmill experimental method to reproduce four representative large-scale public building scenarios (gymnasium, exhibition hall, terminal, and shopping mall scenarios), and two activity states (sitting and walking) in a climate laboratory. Corresponding environmental sound stimuli recorded from the above four types of buildings were played to recreate acoustic environment. Subjective responses and physiological indicators, including electroencephalography (EEG), heart rate variability (HRV), and skin temperature (ST), were also measured. Both the scenario and activity state significantly affected thermal responses and physiological indicators (p ' 0.05). Besides, significant correlations between thermal comfort vote and physiological indicators, and among physiological indicators themselves, indicated that thermal perceptions were influenced by the coordinated processes of central nervous system, autonomic nervous system, and peripheral thermoregulation. The highest thermal comfort occurred in the exhibition hall scenario, with higher Alpha power, lower Beta power, and the ratio of low-frequency to high-frequency (LF/HF) closer to 1, while the shopping mall elicited the strongest discomfort. Compared with sitting state, walking reduced Alpha power, increased Beta power, LF/HF, and ST, and amplified differences among scenarios in thermal perceptions and ST (from 0.32 °C when sitting to 0.49 °C when walking) and in LF/HF at high temperature conditions. These results provided theoretical and practical support for differentiated thermal comfort standards and zoned temperature operation control strategies in large-scale public buildings.