Modern cooling and air conditioning systems depend heavily on refrigerants to keep us safe and comfortable every day. These compounds are in charge of absorbing heat from the environment and moving it to another area, which enables us to produce a cooling effect. However, because of their negative effects on the environment, refrigerants have undergone a major change over time.Various toxic compounds, like ammonia and sulfur dioxide, were frequently employed in the early days of refrigeration. These refrigerants were harmful to the environment and posed serious health hazards. Researchers started looking for safer substitutes as a result. Chlorofluorocarbons (CFCs) became widely used in the 20th century due to their non-toxic and flammability. The Montreal Protocol was established in 1987 to gradually phase down the usage of CFCs as it was later determined that these substances reduce the thickness of the ozone layer.As temporary alternatives for CFCs, hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) were introduced. Although HFCs had a lesser propensity to deplete the ozone layer, it was quickly discovered that they had a high global warming potential (GWP), which significantly influenced climate change. As a result, the Kigali Amendment, passed in 2016, sought to limit the use of HFCs. Hydrofluoroolefins (HFOs) are a new family of refrigerants that were developed to solve these environmental problems. Environmentally friendly alternatives, HFOs have substantially lower GWPs and less effect on the ozone layer. The most well-known HFO is R-1234yf, which is frequently utilized in auto air conditioning systems.Natural refrigerants like ammonia, carbon dioxide (CO2), and hydrocarbons (HCs) have become more common in addition to HFOs. These compounds are exceptionally eco-friendly options because they have very low or no GWPs and no ozone depletion potential. While CO2 (R-744) is used in commercial applications, particularly in supermarkets, ammonia (R-717) is frequently used in industrial refrigeration. Finally, refrigerants have changed dramatically to satisfy environmental standards, moving from hazardous materials like CFCs to more environmentally friendly alternatives like HFOs and natural refrigerants. These developments are essential for reducing climate change and guaranteeing the viability of cooling and air conditioning technology in the future.
