The impact of global warming on personal health is a growing concern, as high temperatures can cause heat stress disorders. Personal cooling systems are a promising solution in environments where air conditioning is not available or infeasible such as the outdoor working environment of utility workers, and treatment of hyperthermia for athletes. However, current untethered personal cooling systems are expensive, heavy, or have a limited cooling duration due to high power consumption. Here, we have designed and prototyped a lightweight and low-power active personal cooling system that uses the non-toxic gallium-based liquid-metal, Galinstan, as the coolant. The Galinstan absorbs body heat as it is pumped through tubing attached to a cooling vest by a low-power DC pump. After absorbing the body heat, the warm Galinstan is cooled by passing it through a network of tubing embedded in cold phase-change material in a cold pack. The cold pack is insulated from the external environment, allowing heat absorption from only the warm liquid metal. To the best of the author’s knowledge, the liquid metal active personal cooling system is 1/3rd of the weight, 1/8th of the price, and cools for 4 times longer compared to the current state-of-art commercial active personal cooling systems.
