Wearable coolers for drivers of racing cars

Thermal stress of drivers

The high temperature exposure inside cars strongly affects the health and performances of drivers. The measurement of thermal stress is related to the physical strain index (PSI), a parameter ranging from 0 to 10. The thermal stress has deep influence on some vital parameters such as heart rate, respiratory rate, oxygen saturation and, of course, body temperature.

High values of the PSI could be mitigated with cooling systems able to provide the driver's body thermoregulation. Unfortunately, many applicative constraints and normative restrictions make the design rather challenging.

Design requirements

To conceive the cooling system we had to consider quite stringent requirements. The FIA (Federation Internationale de l'Automobile) imposes flame retardancy and fireproofing homologation tests. The system must be wearable, then mobility comfort and lightness are mandatory. The driver must feel diffused and smooth refrigeration, and not uncomfortable localized coolings. The system supply is pretty challenging because coolers notoriously demand high energy but the on-board storage is limited. Finally, the physical principle for heat extraction must be selected and the cooler design must be optimized under all the mentioned requirements.

Compact, flexible and reliable

The last version of the wearable cooler is born after many simulations and long experiments on intermediate prototypes. The cooling performances satisfy the needing, with large margins of increment. The energetic efficiency is high enough to use the system for several hours beyond the duration of the typical races. The device is integrated directly into the driver's suite, is flexible and fireproof thanks to the special polymer that constitutes the case. The endurance tests in washing machines provide the necessary evaluation of the system reliability.

Multi-physical simulations

The cooler couples together structural parts, electrical components and fluid flows. This complex nature generates strong interactions to be calculated and optimized. The cooling system performance depends on the accurate simulation of each part behaviour.

Thermal regulation and body monitoring

The real effectiveness of the system relies on the distributed structure of the cooling system. The body parts most sensitive to the refrigeration confort are targeted. A temperature sensor network covering the body provides the cooling system activation and deactivation (the triggering threshold), in order to keep the thermoregulation within the desired range.