Cool using sunlight: this idea seems paradoxical if it turns out to be a concept the original energy: Researchers at the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg are investigating the use of the Solar energy – already used for air conditioning of buildings – to keep it cool perishable foods such as milk, wine or fruit. They demonstrate the viability of this process in the Mediterranean on a business of viticulture in Tunisia and a dairy company in Morocco. Under the project MEDISCO (MEDiterranean food and agro Industry applications of Solar Cooling Technologies), solar installations for refrigeration of milk and wine have been installed in cooperation with universities, energy agencies and European companies. The project, supported by the European Commission, is coordinated by the Milan Polytechnic.
“Our method applies in particular in countries benefiting from sunshine or in remote areas with no possibility of any conventional refrigeration, lack of water or energy resources. It is environmentally friendly, and minimizes the use of electricity needed to operate conventional refrigeration equipment, announces Dr. Thomas Núñez, a scientist at ISE, outlining the benefits of technology. “The cold, always available when the sun shines, and is produced mostly in times of high need.”
Scientists have built solar collectors concentration, direct sunlight with a mirror on an absorber. Thus solar radiation is converted into water leaves at 200 ° C. “This extreme temperature is required to operate the machine absorption refrigeration by the high ambient temperatures outside. Unlike a refrigerator, we do not use electricity to produce cooling, but heat. The result is the same in both cases: the cold as cold water or – in our case – the brine, “says Núñez. Since the machine produces absorption refrigeration temperatures of zero degrees Celsius, the experts want to prevent freezing of water through the mixture used. The brine solution is then stored in tanks of cold and then pumped through a heat exchanger, responsible for cooling the milk. “Cooling the wine is going a bit differently: the refrigerant flows through coils attached to tanks of wine.”
“MEDISCO is a demonstration project. The technique is not applicable in the market,” adds the researcher. “But chances are that the solar cooling can be applied in future in agriculture and chemicals and cosmetics.”