Bastiaan Hemmes found inspiration for this low-tech water cooler in the Zeer Pot, the ‘pot-in-pot fridge’ commonly used in Africa. This consists of a terracotta pot placed inside a bigger one, with wet sand filling the space between the two. The porous earthenware absorbs the water and sweats, so to speak. As the water evaporates the pot, along with its contents, is cooled. Hemmes took this principle and created the Evaporation Cooler, a water container suitable for offices, waiting rooms and public spaces. It not only offers an alternative to the common plastic coolers but also requires no electricity. The only thing you need to do to keep the water cool is water the sand every couple of weeks.