Definition of the Acclimatation Time in Test Room Experiments Through Objective Physiological Indicators

Personalized comfort systems are a promising solution to reduce energy use in building operation. The implementation of personalized environmental management approaches requires understanding how environmental surroundings impact human responses. A common experimental methodology to deepen the knowledge on the topic consists in exposing volunteers to specific combination of stimuli within environmentally controlled and properly instrumented test rooms: laboratory facilities devoted to human-centric comfort studies. A fundamental step in test room experiments is the acclimatation phase which guarantees that retrieved subjects' responses are representative of the actual conditions, not being affected by previous exposures or activities. Nevertheless, there is no consensus on the optimal duration of the acclimatation phase and this study aims to address this gap thanks to physiological signals analysis. Data from two experimental campaigns taking place in the NEXT.ROOM (Perugia, Italy) and targeting different thermal conditions were used to determine the time range for skin temperature stabilization once entering the test room environment – the time of acclimatation. Results showed that 25 minutes can guarantee the stabilization of the skin temperature signals, for at least 75% of the occupants, considering males and females in three different environmental conditions (hot, neutral and cold). In future studies, other physiological signals should be included and confronted with these ones, presenting more thorough analysis of the human physiology.