How can humans gradually solve the problem of "fluorine" that destroys the ozone layer?

When it comes to refrigerants, everyone is familiar with them. Isn't it Freon? However, there are more than one kind of refrigerants. It's just that Freon is more common in our daily life, so everyone is more familiar with it. However, because Freon is very harmful to the environment, refrigerants have been constantly updated in recent years to reduce the harm to the environment.

How does fluorine affect the Earth's atmosphere?

Freon can be roughly divided into three categories, including chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons. Among them, the Freon containing chlorine is the one that damages the ozone layer. When this type of molecule rises to the stratosphere 20 kilometers above the ground, the carbon-chlorine bond (C-Cl) will be cut by strong ultraviolet rays, releasing highly active free chlorine atoms. This altitude area is exactly where ozone (O 3) is concentrated, so it is also called the ozone layer. Free chlorine atoms can convert ozone molecules into oxygen (O 2). During the reaction, the chlorine atoms are not consumed, but can repeatedly catalyze this reaction, so one chlorine atom can destroy thousands of ozone molecules. The near-ground ozone layer is the umbrella of our earth, so these Freons are equivalent to destroying our umbrella, exposing the earth to this strong ultraviolet light, just like we don’t have an umbrella on a rainy day, our bodies will inevitably suffer some damage, and the diseases caused later are even more unpredictable.

For this reason, we need to continuously improve refrigerants to reduce harm to the environment. Currently, the third generation of refrigerants are mainly used, including R32, R125, R134a, R410a, etc.

Studies have shown that the third-generation refrigerants have a significant reduction in GWP (GWP represents the degree of damage to the ozone layer), while the fourth-generation refrigerants have further reduced it on this basis and are approaching infinitesimal.

Therefore, the fourth-generation refrigerant must be the direction of our efforts. At the 2022 China Refrigeration Exhibition, Honeywell will present a series of more environmentally friendly, efficient and safer low global warming potential (GWP) refrigerants. In fact, Europe, the United States, Japan and other countries have been researching the fourth-generation refrigerants as early as 15 years ago, and various patents have long been monopolized by developed countries. Only by taking a different approach can we make our own fourth-generation refrigerants.

China's solution to fluoride

A team from the Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, broke through the traditional thinking in the research of "solid-solid" phase change refrigeration materials, and proposed the innovative idea of ​​"achieving refrigeration effect by driving liquid-solid phase change through hydrostatic pressure" (liquid-solid). They obtained the room temperature Ponzig-Zag effect in the n-alkane system, opening up new ideas for the development of new green and environmentally friendly refrigeration technologies.

This idea uses the fact that a large amount of heat difference will be generated when the material changes phase. During the refrigeration process, the phase change of the material will generate a large amount of cold, thereby improving the refrigeration efficiency, and the material itself has almost no harm to the environment. Using this technology, we can greatly reduce the harm of refrigerants to the environment without reducing the refrigeration effect.

At present, China is carrying out the elimination and replacement of the last type of ODS, hydrochlorofluorocarbons (HCFCs), and has achieved the goals of freezing in 2013, reducing by 10% in 2015 and reducing by 35% in 2020, and is accelerating towards the goal of reducing by 67.5% in 2025. It is believed that with the application of the fourth-generation refrigerants, it will be possible to achieve the goal of improving the overall energy efficiency of refrigeration by more than 20% by 2030, actively respond to the dual carbon goals, and contribute to the international environment.