Today, the traditional gas compression refrigeration is still widely used in household refrigeration equipment, with Freon as the heat exchange medium. However, due to strong ultraviolet radiation, chlorine atoms released by Freon will destroy ozone molecules in the atmosphere for hundreds of years, leading to global greenhouse effect, so this refrigeration medium is being eliminated. Its alternative working medium, hydrofluorocarbons, will also be completely banned in 2028 according to the Montreal Protocol.
In the short time left, who will be the substitute for the next generation of household refrigeration equipment with environmental protection characteristics?
Shen Jun, a researcher at the Institute of Physical and Chemical Technology, Chinese Academy of Sciences, gave the answer: The best solution may be a new generation of solid medium refrigeration technology-magnetic refrigeration.
Shen Jun is in the lab.
Magnetic refrigeration is realized by using the magnetization exotherm and demagnetization endothermic of solid magnetic materials. This new refrigeration method using magnetocaloric effect does not need additional refrigerant, which is a revolutionary technological innovation and is considered as a new generation of green refrigeration method. 20 14 The U.S. Department of Energy has listed magnetic refrigeration as one of the preferred technologies to replace compression refrigeration technology in the future.
Future technology? Yes, although magnetic refrigeration has obvious advantages, it still faces many challenges in materials, devices and systems, and it is very difficult to realize. "My job is to realize the wide application of magnetic refrigeration," Shen Jun said.
In the eyes of many people, Shen Jun is destined to have an indissoluble bond with magnetic refrigeration. Shen Jun, who only came into contact with cryogenic refrigeration when he was a graduate student, soon discovered the ferromagnetic magnetic refrigeration material with the lowest temperature and the largest magnetic entropy change in the world, which filled the international gap in this temperature range and was regarded as "the best magnetocaloric effect system" by international peers. Subsequently, she discovered the hysteresis loss of magnetic materials and its adjustment mechanism, which greatly improved the refrigeration performance of magnetic materials. After discovering potential magnetic refrigeration materials, she also innovatively proposed a new method of composite magnetic refrigeration, and successfully developed a small room temperature magnetic refrigerator with international leading level.
"Every magnetic refrigeration prototype here is made by ourselves." Walking in the corridor of the laboratory, Shen Jun proudly displayed one research and development achievement after another of her team. Seven laboratories are filled with cold instruments and equipment that are difficult for outsiders to see. In Shen Jun's eyes, these "old buddies" who have been with her for many years are her best partners in her work.
Innovation promotes the role of this laboratory of Institute of Physical and Chemical Technology of Chinese Academy of Sciences from a follower, a runner and even a leader of magnetic refrigeration. The magnetic refrigeration prototype developed by Shen Jun's team not only applied for international patent, but also was adopted by American space company. The achievements of cooperation with domestic enterprises have also been applied to scientific research and industrial products, and the output value has reached hundreds of millions of yuan in just a few years.
Shen Jun seems to be more of a researcher, doctoral supervisor, business manager and mother of two children. But you can hardly feel the sense of urgency from her.
"In life, I am a thick line," said Shen Jun, with her long hair hanging over her shoulders and her face slightly tilted. In front of the glass window of Shen Jun's office, a row of succulents are luxuriantly growing. On the far left side of the medal showcase, there are three different styles of coffee machines and coffee capsules, and the opposite side of the sofa is occupied by two irregular Chinese round-backed chairs ... These details in work and life are the true portrayal of her inner calm and composure.
For a girl who chose an engineering major, Shen Jun smiled and said bluntly that her parents "forced her". At the turn of the conversation, she went on to add that now she has really fallen in love with the field of low-temperature refrigeration, especially her achievements are constantly affirmed, more achievements are practical, and even when she is pregnant, she will enjoy doing experiments. Shen Jun picked up a cup of coffee and said with a smile, "Doing scientific research is like drinking a cup of bitter coffee. When you start drinking, you will feel bitter, and then you will feel the sweetness of the result.
As a postdoctoral professor at the College of Future Technology of the University of Chinese Academy of Sciences, Shen Jun opened a course on cryogenic refrigeration in his spare time in Beijing Yanqi Lake Campus to train future talents. As for my motivation and goal, "there is only one," she said, "to be the first practical magnetic refrigerator in the world."
The beauty who comes into the lab to make up is really beautiful.