Self-filling water bottle turns air into water as you ride your bike What do long bike rides; hot, humid days; and thermoelectric cooling have in common? Together, they're part of a innovative new device that may help solve water shortage problems in parts of the world where drinking water is in short supply - or at the very least, make your next bike ride a lot more comfortable. Meet Fontus, a self-filling water bottle that turns air into water as you ride your bike. Created by Austrian Kristof Retezár, an industrial design student at the University of Applied Arts in Vienna, Fontus is attached to a bike frame, where it collects and condenses moisture from the air to produce about two cups of drinkable water per hour. Besides the cool factor, Retezar's solar-powered self-filling water bottle, which is competing for a James Dyson award, an international design competition, has real-world applications. "Fontus can be applied in two different areas," Retezar said. Firstly, it may be interpreted as a sporty bicycle accessory [that's] useful on long bike tours. Secondly, it might be a clever way of acquiring freshwater in regions of the world where groundwater is scarce but humidity is high. Here's how it works: Solar cells on the Fontus power a device that cools the upper chamber of an attached water bottle, leaving the bottom chamber of the bottle to heat up in the sun. As a rider cycles and air is pulled in, it slows, cools, and condenses as it passes through the upper chamber. The moisture from the now-cool air condenses into water and drips through a tube into the bottle. Fontus works best in hot and humid weather - at least 68 degrees Fahrenheit and 50 percent humidity, according to Retezar. Those conditions weren't easy to find in Vienna, where Retezar is a student, so, as the Huffington Post reported, he tested the system in a place that replicated ideal conditions: his bathroom. However, the device does have its limitations. Even under ideal conditions, Fontus produces only about a drop of water per minute - hard work for a cyclist biking on a hot and humid day. It's also not much use in cities, where air pollution would render the condensed water dirty and undrinkable. Nonetheless, the materials for Fontus are cheap - the prototype cost between $25 and $40 to make - and if it wins the Dyson award, Retezar could receive $45,000 to further refine and develop the device and possibly mass produce it. Because a gizmo that makes drinkable water out of nothing but air, at no cost, is too brilliant not to pursue.