It’s easy to take that hulking great white beast of a machine in our kitchens for granted, but for the 1.3 billion people in the world who are living without electricity, a working refrigerator is not an option. So a team of students in Canada has invented a cooling device that not only works without any electricity whatsoever, it’s also cheap and portable, making it ideal for those in remote and rural areas who struggle to keep their produce fresh.
"We thought it would be good to decrease the amount of food waste in the world, and we came up with this design because it's easy to build and the materials are relatively cheap," one of the students, Michelle Zhou from the University of Calgary, told CBC News.
Dubbed the WindChill Food Preservation Unit, the device connects an air tube to an evaporation chamber, which connects to a sealed refrigeration chamber that looks a lot like an esky, the contents of which are cooled through the process of evaporative cooling.
It works by passively drawing in warm ambient air through the funnel, which is fed into a pipe that’s been buried underground. This already starts to cool down the air before it's fed into coiled cooper pipe that’s been immersed in water in the evaporation chamber. The evaporation process is helped along by a small, solar-powered fan.
The water evaporating around pipe chills the air inside, and this is then fed back underground before entering the refrigeration chamber.
The invention won first place in the student category of the 2015 Biomimicry Global Design Challenge, which asks researchers and students to come up with improvements to the global food system inspired by nature. The University of Calgary team says its invention was inspired by everything from coral and kangaroos to bees and elephants - think siphoning air in via elephant ears and keeping things cool underground like termite tunnels.
The next step will be to improve the design to achieve a consistent 4.5 degrees Celsius temperature in the refrigeration chamber, which is what’s needed to keep food from spoiling.
"Anywhere from a quarter to half of the world's food goes to waste every year, and in rural populations - about 70 percent of the people in rural Africa don't have access to electricity," team member Jorge Zapote told CBC News. "So this at the moment uses a tiny bit of electricity from a solar panel, but the end design is to use zero electricity. So this could really help people in those areas."