The impact of electric heating cape on local thermal sensation and thermal comfort of officers

This study focuses on evaluating the thermoregulatory performance of a graphene-based electric heating cape and determining its optimal temperature for use in cool indoor environments during winter. Through controlled experiments with 30 participants in a climate chamber maintained at 15.5 °C, five heating conditions (no heating, 35 °C, 40 °C, 45 °C, and 50 °C) were systematically tested. Skin temperature and heart rate were continuously monitored, and subjective thermal sensation and comfort votes were collected using 7-point scales. Results demonstrated that the electric heating cape significantly improved thermal comfort, with 40 °C identified as the optimal temperature setpoint: overall thermal sensation shifted from slightly cool to slightly warm, and overall thermal comfort state attained 'slightly comfortable' level on the adaptive comfort scale. Repeated-measures ANOVA revealed that heating temperature had a highly significant effect on both overall thermal sensation and overall thermal comfort. Post-hoc tests identified 40 °C as the optimal temperature setpoint under these environmental conditions (15.5 °C). At this temperature, the overall thermal sensation vote improved significantly from - 1.23 (no heating) to -0.13 (p < 0.01), approaching a neutral sensation, while overall thermal comfort increased significantly from - 1.08 to 0.35, reaching a "slightly comfortable" level. The most significant improvements were observed in the abdomen and lumbar regions. While skin temperature showed a positive correlation with thermal perception, heart rate remained stable (± 5 bpm), indicating a low physiological burden. Marked individual differences in temperature preference underscore the importance of personalized thermal regulation. This study provides empirical evidence to guide the application and control of localized heating devices in cool indoor office settings during winter.