Gizmos & Gadgets: Evaptainers Keep Food Cool Without Electricity

August 26, 2016 – A Massachusetts-based company that owes its origin to a class project at the Massachusetts Institute of Technology, has created a refrigerator that works without electricity. It is a solution to improve the lives of 1 billion on this planet.

Evaptainers use evaporative cooling, something you experience on a hot day when you splash water on your skin and experience a cooling effect as it evaporates.

How do you apply this phenomenon to preserving food?

It is really quite simple. You create a cooler-sized tub (see illustration below) that consists of an inner waterproof storage chamber and surround it with an outer chamber filled with a water-permeable substance. You then create a means to feed water to the outer chamber just enough so that the water can be absorbed and then evaporate. As it evaporates the cooling effect to the interior chamber produces a  temperature drop of about 20 Celsius (36 Fahrenheit) compared to the outside temperature.

The Evaptainers prototype holds 60 liters of food and uses one liter (a little more than a U.S. quart) of water every two days. Recently 25 Evaptainers were tested in Morocco successfully and the company has plans for a second field test involving 500 units this year. Half of these test units will be given away while the remainder will be sold at $25 US each. Commercial launch is yet to be announced.

What’s the immediate problem Evaptainers solves?

The United Nations Food and Agriculture Organization estimates $310 billion worth of food is wasted through spoilage annually in Developing World countries. Spoilage rates can be as high as 45% for fruit and vegetables. Lack of refrigeration is one reason. But poor post-harvest storage infrastructure, and inadequate transportation to bring food to local consumer markets contribute as well. For Developing World nations this problem of spoilage produces a significant drain on their economies and makes many of them food dependent on imports even for crops that they are already growing.

One of the key features that makes Evaptainer such an appropriate solution for its target market is its size. The picture above doesn’t give you a sense of its actual dimensions. But I found a picture online that shows this very well while demonstrating just how much produce a single Evaptainer can hold. It is surprisingly a lot. Everything displayed in the foreground of this picture was brought to market in the single Evaptainer being held up by the man in the picture.

Typical capacity, enough room to hold up to 150 apples and oranges and keeping them fresh for 12 hours, a long enough time to get the produce to market whether strapped to the back of a motorbike, or riding on the back of a mule. Seems Evaptainers are ideal for small farm holders who can daily harvest and deliver produce to local markets without spoilage.