Development of a Cooling Garment With Encapsulated PCM

Abstract

Abstract Under SBIR (Small Business Innovation Research) programs from the U.S. Marine Corps, investigators at Triangle Research and Development Corporation (TRDC) have conducted research toward the development of a unique passive cooling garment to provide significant microclimate cooling to Marines dressed in NBC (Nuclear/Biological/Chemical) protective clothing. The patented PECS (Protective Environmental Control System) garment utilizes 3–4 mm diameter macroencapsulated phase change material (macroPCM) particles distributed throughout a lightweight and highly breathable vest garment to provide 1–3 hours of cooling in high heat stress environments. With polymer walls encapsulating the paraffin PCM, the macroPCMs provide a wearable, packed bed heat exchanger that is flexible, highly breathable, and undergoes its solid/liquid phase change from 25–28°C, where its high latent heat storage can reach 60 calories/gram. This cooling range is at elevated and more comfortable temperatures than gel media used in other passive microclimate garments, which store their cold near 0°C and can cause shivering and discomfort. Although other microclimate garments require refrigeration or freezers to thermally recharge the cooling media, the passive 5-lb PECS cooling garment can be thermally recharged in the field at room temperatures (15–20°C) without refrigeration. Although earlier publications described the principles for such a cooling garment, this publication is the first to describe the garment’s construction, development and testing. Extensive laboratory testing has included Marine volunteers on a treadmill in a heated environmental chamber while dressed in Level IV MOPP and Level A protective clothing and a gas mask. PECS has also been used by costumed characters at Walt Disney World to provide extended cooling within an extended heat stress environment. Besides military uses, passive macroPCM garments should find other applications; including: protective clothing for firefighters, industrial workers, costumed characters and persons with heat stress disabilities.