<\/span><\/h2>\nAir conditioners produce cool wind, and refrigerators store food safely. This is all made possible by a special medium, the refrigerant.<\/strong> Refrigerants absorb heat from their surroundings or high-temperature substances, reducing the temperature. They are often used in cooling devices to make air cool and fresh. <\/span><\/p>\nThe principle of refrigerants can be found easily in our daily lives. For example, on a hot summer day, when you spray water on the ground or road, the water absorbs heat as it evaporates, creating a cooling effect. Similarly, the ice packs used in delivering meat or seafood use the same principle. The engine coolant used as a heat source for the heater in internal combustion engine (ICE) vehicles is also a type of refrigerant that takes away engine heat and discharges it outside. In essence, a refrigerant is a substance for transferring heat<\/strong>.<\/span><\/p>\nWhat is interesting is, as mentioned earlier, the refrigerants used in EVs<\/strong> are not only used for cooling but also for heating<\/strong>. So how is this possible? <\/span><\/p>\n<\/span>\u2744\ufe0f <\/span> The evolution of refrigerants for environment and efficiency <\/span><\/span><\/strong><\/span><\/h2>\nRefrigerants are categorized into natural refrigerants<\/strong> and synthetic refrigerants<\/strong>. Ammonia (NH3), hydrocarbons (HCs), and carbon dioxide (CO\u2082) are common examples of natural refrigerants. Natural refrigerants are substances that exist in their natural state, thus having a minimal impact on the environment. However, they are characterized by low efficiency, and most have issues with toxicity and flammability, which can pose potential harm in case of leakage <\/span><\/p>\n![\"\"](\"https:\/\/askinno.com\/global\/wp-content\/uploads\/sites\/2\/2024\/02\/SKI_\uc774\ubbf8\uc9c0\uc81c\uc791\uc694\uccad\uac74_R1_\uc601\ubb38_02_Rev1-1.png\")
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Synthetic refrigerants<\/strong> were developed to overcome those issues the natural ones. In the 1930s, the first generation of synthetic refrigerants was developed. Chlorofluorocarbon (CFCs) series organic compounds<\/strong> were harmless to humans and not easily flammable. These refrigerants were widely used for a long time due to their high stability. However, by the late 1980s, it became known that CFCs were severely depleting the ozone layer in the atmosphere. As a result, the United Nations (UN) banned and regulated substances through the Montreal Protocol*.<\/span>
\n(*) Montreal Protocol: Officially known as the \u201cMontreal Protocol on Substances that Deplete the Ozone Layer\u201d It aims to minimize the damage to humans, animals, and plants caused by ozone layer depletion through the prohibition and regulation of substances that destroy the ozone layer, such as chlorofluorocarbons or Freon gas, and halons. It was adopted in September 1987 and came into effect in 1989. South Korea joined the protocol in February 1992, and it was enacted in May.<\/span><\/em><\/p>\nIn a continuous global effort to reduce the environmental destruction caused by refrigerants, the fourth-generation Hydrofluoroolefins (HFOs)<\/strong> are currently replacing previous-generation refrigerants. The representative fourth-generation refrigerant R-1234yf, developed by global chemical giants, has an ozone depletion potential of 0 and a global warming potential of 4. This is widely utilized as it has the least impact on climate change among the synthetic refrigerants that have been developed so far. However, HFOs are more expensive and flammable compared to previous refrigerants. <\/span><\/p>\nThe major substance of fourth-generation refrigerants is hydrofluoroolefin (HFO). HFO is made of perfluoroalkyl and polyfluoroalkyl substances (PFAS). PFAS possess exceptional properties, such as water resistance, heat resistance, and corrosion resistance. They have been used for decades as raw materials or coating agents for automotive refrigerants, vehicle batteries, and electronic components. Especially they played a role in preventing corrosion in automotive refrigerants and enhancing durability for long-term use. <\/span><\/p>\nHowever, as the negative impact of PFAS on the environment and human body was disclosed, the European Union (EU) announced a policy to broadly restrict PFAS. From 2026, restriction on the use of PFAS is expected. The US is also classifying PFAS as a toxic substance and is currently strengthening regulations. Therefore, the development of new-generation refrigerants<\/strong> that can surpass the fourth-generation synthetic refrigerants in terms of safety is required. <\/span><\/p>\n
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