Cool without electricity: MIT find to better keep food or optimize air conditioning

How keep food in the fridge When we have neither fridge nor current? MIT researchers in the United States think they have found a solution. They developed a device capable of lowering the temperature by several degrees, without consuming electricity. The objective is twofold: to keep fruits, vegetables or drugs longer in places where electricity is rare, or during power cuts, but also optimizing the energy consumption of air conditioning systems.

A triple layer “magic panel” without connection

The device, tested on the roofs of the MIT campus, associates three physical principles: radiative cooling (which returns heat by radiation), evaporative cooling (by evaporation of water) and effective thermal insulation. Result: a lowered temperature of 9.3 ° C compared to ambient air, even in warm and humid weather. According to the researchers, this would extend the storage time of food in the wet environments by 40%, and up to three times more in dry areas.

The system consists of three main layers. On the surface, an aerogel placed in a polyethylene structure, ultralight and very insulating material, lets the water vapor and infrared radiation pass, while reflecting sunlight. Below, a layer of hydrogel stores the water which evaporates slowly to produce cold. Finally, a mirror layer reflects residual solar heat, limiting the warming of the whole.

This unprecedented combination allows the device to operate without power supply, with moderate water consumption: a simple addition of water every four days in dry climates, or monthly in wet areas.

Various uses in many countries

In rural areas or badly connected to the electrical network, especially in Africa or Asia, this invention could make the difference. She could also support Air conditioning systems classic, by reducing their energy consumption.

There remains a major challenge: for the moment, one of the materials used, a very light insulation called aerogel, is still expensive to produce. Researchers are looking for cheaper alternatives to be able to make this system on a large scale.

But the idea already appeals to experts. According to a Purdue University engineer, this mixture of simple techniques in the same device could change things: “These works could have important practical applications, especially for food conservation, if the system can be made at a reasonable cost.”