Any time there’s a prolonged power outage in warm weather, chances are that one of your first thoughts is “What’ll happen to all the food in my fridge?”. Well, imagine if instead of a week’s worth of groceries, your unpowered refrigerator was full of vaccines, vital to the well-being of an entire African village. In rural third world countries, power failures are common, as are high temperatures – not a great combination for things that need to be kept cold. Fortunately, some aid agencies have the option of using a True Energy Vaccine Refrigerator. It can store US$30,000 worth of medicine below 10C (50F) in 43C (109F) ambient temperatures, for over ten days at a time, without power.

The refrigerator runs off mains power, solar power, or a combination of sources. It incorporates True Energy's Sure Chill technology, which utilizes high-density polyurethane foam insulation and an undisclosed “innovative phase change material” to store energy until it’s needed, allowing for consistently cool temperatures regardless of interruptions in the power supply. It can run indefinitely on less than five hours of mains power per day. Once fully charged, as already mentioned, the phase change material can keep the fridge going for ten days without any power input at all. As a side benefit, this non-battery power-storing capability is also said to make it twice as energy-efficient as similar products.

Utilizing an intelligent monitoring system, it detects warm objects within its cabinet and reacts to extract heat, keeping all of its contents at a temperature of between 4 and 6C (39 and 43F). According to the company, other systems can inadvertently freeze some objects as they try to maintain the correct temperature for others.

True Energy Vaccine Refrigerators are currently in use by agencies such as the World Health Organization and Unicef. The company is also looking into using its Sure Chill technology in products such as commercial refrigerators, drinks coolers, air conditioners and telecommunications infrastructure cooling.