Physiological comfort evaluation under different airflow directions in a heating environment

Area of Science:

• Environmental Science
• Human Physiology
• Building Science

Background:

• Subjective assessments of indoor airflow and thermal comfort are limited by individual variability.
• Objective physiological measurements are needed to complement subjective evaluations for accurate comfort assessment.

Purpose of the Study:

• To evaluate indoor airflow and thermal comfort using physiological measurements.
• To compare the effects of indirect versus direct airflow on physiological responses and mental stress.

Main Methods:

• Twenty participants were exposed to indirect and direct airflow at different speeds (0.123 m/s and 0.225 m/s) in a 30°C room.
• Physiological data, including electroencephalography (EEG), respiration, and skin temperature, were collected during various tasks.
• Participants underwent subjective evaluations alongside objective physiological monitoring.

Main Results:

• Lower amplitudes in gamma and beta EEG bands were observed under indirect airflow conditions at specific brain sites (T3, P7).
• Respiration variability was significantly lower with indirect airflow (p < 0.010).
• EEG gamma and beta wave amplitudes correlated with anxiousness levels (e.g., gamma at T3: r = 0.41).

Conclusions:

• Indirect airflow appears to induce less mental stress and fatigue, correlating with enhanced thermal comfort.
• Physiological measurements provide a valuable tool for assessing unconscious indoor comfort, complementing subjective feedback.