Under scorching summer conditions, even light activity induces profuse sweating. Heat stress in high-temperature work environments has emerged as a growing societal concern in recent years, driving researchers to seek effective solutions for mitigating thermal strain and safeguarding worker health.
Integrating cooling systems into protective garments represents a key strategy. Common systems include gas-based, liquid-based, and phase-change material (PCM) cooling. PCMs, as novel thermoregulatory materials, possess heat storage and release capabilities, enabling them to establish a relatively stable microclimate around the wearer by dynamically responding to ambient temperature fluctuations. By embedding PCM cores into vests, users essentially "carry portable air conditioning." These vests modulate heat exchange to maintain body temperature within a cool, comfortable range.
PCM cooling packs (PCM Packs), fabricated from solid-liquid phase-change materials, are inserted into vest pockets and worn beneath protective gear to alleviate heat stress. Comparative studies of subjects wearing PCM vests under firefighting gear versus those without demonstrated that PCM vests significantly reduce skin and core temperatures during high-heat exposure.
To activate the vest, users simply pre-cool the PCM inserts in a refrigerator for half an hour. Once deployed in outdoor environments above 30°C, the vest provides up to two hours of continuous cooling. PCM-based cooling offers distinct advantages: it eliminates condensation issues and is environmentally benign, gently regulating body temperature without abrupt thermal shocks.
The "air-conditioning vest" combines innovative design and functionality to enhance comfort for workers in extreme heat. Recognizing that many users engage in physically demanding tasks requiring shoulder mobility (e.g., carrying heavy loads), developers strategically placed cooling agents on the vest's front and back panels, leaving shoulders unencumbered.
Research confirms that partial-body cooling effectively lowers body temperature to prevent heatstroke. Compared to whole-body cooling, this approach enhances comfort and efficacy while promoting heat dissipation in hot environments. In summary, targeted cooling serves as a practical intervention against heat stress. Future efforts should focus on optimizing application methods and expanding use cases to advance occupational health protection.
