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2022-08-14
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Sino US scientific research teams have developed a "twisted fried dough twist" refrigeration method

Sinochem news the scientific research teams of China and the United States have developed a new flexible refrigeration method, which uses materials such as rubber, fish wire and nickel titanium alloy to realize refrigeration like "twisted fried dough twist", which is expected to significantly improve the efficiency of heat engines, save electric energy and reduce refrigeration costs

recently, its main function is to amplify the weak signal generated by the sensor. The research published in the American journal Science on the day shows that this new strategy, known as "twisted heat refrigeration", first twists the fiber, and then untwists it to achieve significant cooling. Its Carnot efficiency can reach 67%, which is higher than the Carnot efficiency of traditional air compression refrigeration, which is less than 60%. Carnot efficiency is an index used to measure the maximum working efficiency of a heat engine

it is reported that at present, the conversion rate of air conditioners and refrigerators can be adjusted dynamically. Refrigeration consumes about 20% of the global electric energy, and the demand will continue to increase, which will further aggravate the global greenhouse effect. Improving refrigeration efficiency is an urgent problem to be solved in the scientific community

the team led by researchers from Nankai University in China and the University of Texas at Dallas in the United States fixed both ends of the fibrous rubber elastomer, twisted one end to form a supercoil structure similar to DNA, and doubled the fiber. Then, the structure after elongation and twisting is cooled in the rapid release, and the maximum temperature drop point can be reduced by 16.4 degrees Celsius

according to liuzunfeng, the co-author of the paper and a professor at the school of pharmacy of Nankai University, the traditional "elastic thermal refrigeration" needs to lengthen the rubber band by 6 to 7 times and then retract, "torsional thermal refrigeration" is twice as efficient as its Carnot efficiency and smaller

the research team also achieved the cooling effect by using rigid polymer materials with stronger durability such as fishline and textile thread, and the cooling effect under the same deformation is stronger than that of rubber. The research also shows that when four nickel titanium alloy wires are twisted and untwisted, the maximum temperature drop point can be 20.8 degrees Celsius, the overall average temperature drop can reach 18.2 degrees Celsius, and a refrigeration cycle is only about 30 seconds

researchers made a refrigerator model based on this. Using three Nitinol wires to cool the flowing water, untwist 0.87 turns per cm to obtain a temperature drop of 7.7 degrees Celsius

researchers also coated the surface of the material with thermochromic paint to make the fiber change color reversibly with the twist change. It is expected to be used in wearable devices, visual sensors and intelligent color changing fabrics in the future

on the cylinder and plane

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