Physiological-feedback-driven localized heating: Coordinating energy efficiency and thermal comfort

Balancing occupant comfort and building energy use is a global challenge. Localized heating offers comfort with lower energy consumption. However, it lacks systematic evaluation of physiological and subjective effects, and lacks guidance on strategy selection across activity types. An experiment was conducted in a 16 °C cold environment. A localized heating system was used, with the surface temperature of the heaters maintained at 50 ± 3 °C. The study involved 16 university students, including 8 males (age: 23 ± 2 years; BMI: 26.2 ± 5.6 kg/m²) and 8 females (age: 23 ± 2 years; BMI: 23.4 ± 2.5 kg/m²), wearing standardized clothing (approx. 1.25 Clo.). A database containing 3026 sets of electrocardiogram (ECG) and electroencephalogram (EEG) physiological signals (measured via three-electrode wearable sensors, for prefrontal brainwave capture) and subjective feedback data was developed under different heating modes and two seated activity conditions: resting and working. Findings: (1) Localized heating significantly affected physiological signals and questionnaire responses (p < 0.05). Thermal discomfort dropped from 75 % to 0–27 %, and cold votes decreased from 63 % to 0–22 %. (2) For resting, single-zone core heating was the most effective, with the root mean square of the difference between adjacent RR-intervals (RMSSD) and beta brainwave as reliable thermal comfort predictors. For working, multi-zone core heating was the most effective, with alpha brainwave being a suitable predictor. (3) Compared to air conditioning, localized heating saved 35.0 %–75.6 % energy. This study identifies activity-dependent strategies and key physiological indicators for development of personalized thermal comfort systems.