This article originally appeared in The Telegraph. Below is an excerpt.
Vaccines are often temperature sensitive, with inoculations for diseases including hepatitis, typhoid and polio sensitive to both high and low temperatures.
This presents a major challenge for health workers dispensing vaccines across the world, particularly in areas with limited or unreliable electricity supplies.
But Sure Chill, a British technology and energy company based in Cardiff, has developed a fridge which “harnesses the power of nature” to protect sensitive medical supplies from power cuts.
The fridge, which has almost 20 models and is used in 49 countries, is based on the principle that water is heaviest at 4°C. A cold compartment in the fridge is surrounded by water, which cools when connected to power and forms a layer of ice above the chamber.
When electricity is switched off, the warm water rises while the ice begins to melt, keeping the water at a constant temperature. It can keep the contents chilled for up to four weeks without power.