Circool

What it does

Circool is a wearable wrap that continuously cools a heatstroke patient during transport. Unlike traditional ice packs that only cool small areas and must be replaced, Circool encircles the abdomen, arms, and legs with ice-water contact over a large surface.

Your inspiration

The idea for Circool came from real military cases where soldiers died from heatstroke due to heavy gear and limited cooling time. Existing methods like cooling immersion and TACO are effective but interfere with transport. We aimed to replicate the wide-area cooling of immersion by using water and maintaining contact with the body through ice packs. To solve the challenge of cooling during movement, we developed the concept of a wrap that keeps the patient cool without interrupting transport—leading to the creation of Circool.

How it works

Circool is a wearable cooling device engineered to rapidly lower the core temperature of heatstroke patients and sustain cooling throughout transport. The system comprises a water layer in direct contact with the skin and an overlying ice‑pack layer that keeps the water cold. As the chilled water spreads evenly across the skin’s surface, heat is conducted away from the body more efficiently. This design achieves the critical emergency cooling rate of 0.1 °C per minute.

Design process

In the military, heatstroke first aid typically involves placing ice packs on specific body parts and spraying water. However, this method often interferes with transport and is not effective in lowering core temperature. Since survival rates increase significantly when treatment is given within 30 minutes, continuous cooling during transport is essential. To achieve a higher cooling rate, we focused on delivering cold water directly to a broad area of the skin. Studies show that localized ice pack cooling achieves only about 0.025°C/min, while partial-body immersion in ice water achieves around 0.20°C/min, proving wider contact improves effectiveness. Our initial concept—a pump-based stretcher system—was too bulky and impractical in emergencies. We then redesigned it into a wrap format usable on the torso, arms, and legs. For portability and body conformity, we selected semi-cylindrical ice packs that can be rolled when not in use. The rounded side faces the skin to minimize direct ice contact and allow cooled water to spread broadly, maximizing heat transfer. The result is a portable, reusable solution that enables efficient cooling during patient transport.

How it is different

Circool is a wearable cooling system that enables patient transport while providing effective, continuous cooling for heatstroke first aid. Unlike traditional methods that place ice packs on small areas like the armpits or groin—requiring constant caregiver attention—Circool uses a belt-like wrap secured around the upper body to maintain stable contact during movement. Water touching the skin stays cold thanks to built-in ice packs, delivering broader, more efficient cooling. While cold-water immersion and the TACO technique work well, they need large amounts of resources and are impractical during transport. Circool solves this by offering a portable solution that deploys quickly without bulky equipment. It uses more coolant across a larger area than standard ice packs, ensuring hands-free cooling while evacuating patients.

Future plans

We will first simulate stretcher-based evacuation scenarios in a controlled environment, measuring cooling performance across various body positions and movements while continuously tracking core and skin temperatures. Next, we’ll conduct usability testing with military medics and EMTs under simulated high-stress conditions, recording donning/doffing times, ease of use, and comfort feedback. A diverse sample of body types will be included to ensure full range of motion. Finally, we’ll test field re-cooling and cleaning procedures to confirm rapid redeployment without specialized tools.

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