# Effect of Exposure Time on Thermal Behaviour: A Psychophysiological Approach
###### Abstract  
This paper presents the findings of a 6-week long, five-participant experiment in a controlled climate chamber. The experiment was designed to understand the effect of time on thermal behaviour, electrodermal activity (EDA) and the adaptive behavior of occupants in response to a thermal non-uniform indoor environment were continuously logged. The results of the 150 h-long longitudinal study suggested a significant difference in tonic EDA levels between \"morning\" and \"afternoon\" clusters although the environmental parameters were the same, suggesting a change in the human body's thermal reception over time. The correlation of the EDA and temperature was greater for the afternoon cluster (r = 0.449, \(p<0.001\)) in relation to the morning cluster (r = 0.332, \(p<0.001\)). These findings showed a strong temporal dependency of the skin conductance level of the EDA to the operative temperature, following the person's circadian rhythm. Even further, based on the person's chronotype, the beginning of the \"afternoon\" cluster was observed to have shifted according to the person's circadian rhythm. Furthermore, the study is able to show how the body reacts differently under the same PMV values, both within and between subjects; pointing to the lack of temporal parameter in the PMV model.  
Thermal comfort; thermal health; biosignals; electrodermal activity; thermal behaviour 2021202  
costs [9], not to mention unforeseen expenditure on carbon budgets (energy efficiency gaps) [10].  
New approaches to all these established methods have been arising recently that can be categorized in a \"dynamic comfort\" theory, in which the thermal perception is defined by a profile of the spatio-temporal dynamics of the human body, rather than the homogeneous single optimum condition of an environment [6].  
Studies investigating the acceptance [11, 12] and endurance [13] of thermal stress in environments with larger temperature variations showcase that there is, in fact, no necessity for homogeneous conditioning as long as the participants were given adaptive opportunities.  
While the idea of strict thermal indoor environments seems outdated, the new work culture of recent years has also proven itself to be more flexible than previously known. Even before the rise of remote-working in the past 1.5 years, companies were already experimenting with the idea of shared and mobile workstations, where the occupant was free to choose their preferred space in the building. Now that the possibility of partial or fully remote work is added to the discussion, schedules are considerably different--the latest ICT technologies have made the 8 to 5 work day in front of the same static screen redundant, added the flexibility of time and the flexibility of space.  
Considering these points, the authors propose to exploit this spatio-temporal flexibility in favour of free-running and/or less conditioned spaces, with potentially higher cooling set point temperatures. The hypothesis is that, as an alternative to homogenously conditioned spaces throughout the day, it might be possible to reduce both the conditioning period and amount of the conditioned spaces while avoiding thermal stress.  
In order to investigate this, a 6-week long experiment is designed to replicate such a flexible scenario, and the stress and relief are quantified through the constant measuring of physiological data.