The burning question of energy saving and environmental protection from harmful substances used in refrigerators has received an unexpected solution. Engineers from Germany have designed the original cooling system, based on the unique properties of the alloy of nickel and titanium.
The alloy called nitinol has a “shape memory”. The material absorbs heat from the environment when stretched and radiates it when compressed. According to the information provided by the developers, the minimum temperature difference reaches a significant 20°C, which allows creating cooling devices or refrigerators.
The prototype of German engineers is a cylinder, wrapped with bundles of nitinol wire. When the cylinder rotates, the wire gets stretched and absorbs heat. Next, the wire uses the “memory effect”, returns to the original shape and produces heat.
The main task of the engineers is to ventilate the wire properly to remove cold or warm air. It is important to make an accurate calculation of the diameter of the wire, the cylinder, the number of bundles and the fan parameters. When testing the maximum energy extraction in the laboratory, the developers received a power 30 times greater than the effort needed to stretch the wire.
The device, developed in Germany, has shown the results that are 2 times higher than the efficiency of a heat pump and 3 times better than a traditional refrigerator. In this case, the system does not use any toxic refrigerant, and there is no need to create a system of heat exchangers. Nitinol is highly resistant to cyclic loads, which allows the invention to be used for a long time. The cost of such environmental-friendly fridges is not specified.
