Application of wearable EEG sensors for indoor thermal comfort measurements

Silvia Angela Mansi,Ilaria Pigliautile,Marco Arnesano,Anna Laura Pisello,Camillo Porcaro

doi:10.21014/acta_imeko.v10i4.1180

Abstract

Multidomain comfort theories have been demonstrated to interpret human thermal comfort in buildings by employing human-centered physiological measurements coupled with environmental sensing techniques. Thermal comfort has been correlated with brain activity through electroencephalographic (EEG) measurements. However, the application of low-cost wearable EEG sensors for measuring thermal comfort has not been thoroughly investigated. Wearable EEG devices provide several advantages in terms of reduced intrusiveness and application in real-life contexts. However, they are prone to measurement uncertainties. This study presents results from the application of an EEG wearable device to investigate changes in the EEG frequency domain at different indoor temperatures. Twenty-three participants were enrolled, and the EEG signals were recorded at three ambient temperatures: cold (16 °C), neutral (24 °C), and warm (31 °C). Then, the analysis of brain Power Spectral Densities (PSDs) was performed, to investigate features correlated with thermal sensations. Statistically significant differences of several EEG features, measured on both frontal and temporal electrodes, were found between the three thermal conditions. Results bring to the conclusion that wearable sensors could be used for EEG acquisition applied to thermal comfort measurement, but only after a dedicated signal processing to remove the uncertainty due to artifacts.

Highlights

Human-building interaction is an essential subject studied in the last decades, aimed at ensuring the occupants’ wellbeing and the correlated influence on buildings’ energy consumption
EEG features were divided into three groups according to the thermal sensation scores expressed by the participants in the questionnaire
Some studies revealed that EEG theta waves increased while beta waves decreased with a comfortable thermal state, others showed that high values of theta band correspond to a high state of arousal level and vice versa

Summary

Introduction

Human-building interaction is an essential subject studied in the last decades, aimed at ensuring the occupants’ wellbeing and the correlated influence on buildings’ energy consumption. In the last 3 decades, the adaptive model was widely used [3] It is based on findings from the simultaneous collection of data on the thermal environment and thermal response of subjects, to determine the indoor thermal states, and the influencing parameters, that satisfy occupants’ sensations. The resulting adaptive models provide experimental relationships between the thermal comfort temperature and the outdoor air temperature. Neither of those models encompass the personal physiological and psychophysics influence on the individual thermal perception. The concept of the personal comfort model has been introduced as a novel approach to predict individual-specific thermal comfort based on the measurements of environmental quantities, occupants’ behaviour, and physiological responses

Methods

Results

Conclusion