Life in northern Nigeria is particularly hard, here the communities live in a semi-deserted rural area and most of the population makes ends meet through assisted agriculture. Due to the lack of refrigerators, food spoilage is a major problem in remote locations like this one.
In 1990, Mohammed Bah Abba, to improve the living conditions of his people in Nigeria, built and distributed at his expense, more than 10,000 vases, real green refrigerators which do not need any kind of electricity to work. Abba's work was awarded by Rolex, the watch manufacturing company, so Mohammed Bah Abba was one of the few recipients of the Rolex award.
THE vases of Abba they consist of two terracotta containers, one inside the other, separated by a layer of sand. Pots covered with a wet patch are placed in a well-ventilated area. The water filters towards the surface of the outer vessel and quickly evaporates in the dry desert air, thus, the water present in the vessel and the food it contains, cool.
Following a similar thermodynamic principle, Caterina Falleni, an Italian researcher, designed a green refrigerator baptized Freeijis. The green refrigerator by Caterina Falleni, has the characteristics of a perfect refrigeration apparatus for storing fruit and vegetables.
Freeijis, the modern version of the Abba vase
Like the Abba vase, the green refrigerator by Caterina Falleni consists of two containers; We see an external container in terracotta and an internal one in aluminum. Between the two containers there is a cavity that contains the water intended to evaporate.
The Abba vase served as inspiration in many areas. Exist drip coolers that successfully exploit the same principle, these are cheap air conditioners that see a continuous dripping of water that wets a roof of thatch or other porous material. When the air passes through the moist material it cools and that's it.