Immunisation is one of humankind's greatest health success stories. It averts two to three million deaths a year. In 2015, about 86 percent of kids worldwide received three doses of the diphtheria-tetanus-pertussis vaccine, protecting them from disability or an untimely death.
But we could be doing more. The World Health Organisation estimates that an additional 1.5 million deaths could be avoided every year if global vaccination coverage was improved. That's tricky, because many vaccines require a constant temperature to stay effective.
In many developing countries, ice is used to keep vaccines cool, mainly because it's cheap. But ice is unreliable and doesn't last very long. So William Broadway, an industrial design student at Loughborough university, has developed an alternative. It's called the Isobar, and has just won the UK James Dyson Award 2016.
How it works
The Isobar uses a chemical process to create a cooling effect. First, a propane burner is used to heat a mixture of ammonia and water in a chamber at the bottom of the device. That causes the ammonia to boil off and float through a valve into an upper chamber, where it cools and condenses back into a liquid again.
When cooling is needed, the device is upended and the ammonia slowly evaporates, passing back through the valve and into the water. The evaporation process creates a cooling effect - enough, Broadway says, to keep vaccines at a safe temperature.
The principle is based on an early refrigerator design, created in the 1920s but shelved after the spread of more-efficient electric refrigeration. With the rapid spread of renewable electricity and off-grid energy sources across the developing world, the same fate may come of the Isobar in time. The other factor working against it is its cost - while the device is relatively simple and cheap to produce, it's hard to see it ever becoming cost-competitive with ice.
Broadway entered his invention for the James Dyson Award - the Isobar won the British competition, and Broadway will be given £2,000 to develop the idea further.
He plans to use that money to build more prototypes and file for patents. The product will also now be entered into the running for the international James Dyson Award, which comes with a further £30,000 prize.
Jack Lang, co-founder and chair of Raspberry Pi, helped judge the award. He told TechRadar: "Isobar is a brilliant invention. It solves a real problem and is a complete, well-thought-through system."
Full disclosure: the editor of this story was also part of the judging panel for the UK James Dyson Award 2016.