The Chilly personal water cooler is an evaporative cooler for use with personal hydration systems. Originally intended for military use it is also perfect at enhancing the performance of outdoor athletes. Access to cool drinking water encourages the user to stay hydrated and delays potentially harmful heat injuries in high ambient temperatures.

The Chilly cooler unit is mounted on the outside of a personal hydration system, midway along the drinking tube. Water enters at one end and passes through 12 cooling fins, each fin houses a wick that transports a small amount of drinking water, by capillary action, to the outer covering fabric from where it evaporates to atmosphere cooling the water within. The water is cooled progressively as it passes through the unit emerging at about 10% above the wet bulb temperature.

The key inventive step was the use of wicks that allow water to flow through from the inside to the outside but prevent air entering the system. A semi-permeable membrane does not serve the same function as when a drink is taken the pressure within the unit can drop below ambient and air will enter the unit making it impossible to drink.

The whole unit has a robust perforated outer cover for protection and is constructed from high grade engineering polymers that offer light weight, robustness and no risk of Bisphenol A contamination. All plastic components are injection moulded to high tolerances and ultrasonically welded together.

A fully adjustable harness allows the Chilly water cooling unit to be mounted onto most major brands of personal hydration pack.

The wicks and fabric covering contain silver threads that act as anti-microbial and anti-fungal agents.

The Chilly water cooler uses no power and no consumables (other than a small amount of the drinking water).