The primary characteristic of a chemical used as a refrigerant is its ability to absorb heat from the surroundings at a low temperature and pressure and release that heat at a higher temperature and pressure. In other words, the chemical should have a low boiling point and a high latent heat of vaporization.
Additionally, the chemical should have good thermodynamic properties, such as high energy efficiency, low toxicity, non-flammability or low flammability, and compatibility with the materials used in refrigeration systems. Environmental considerations are also important, and modern refrigerants are expected to have low ozone depletion potential (ODP) and low global warming potential (GWP) to minimize their impact on the ozone layer and climate change.
In recent years, there has been a shift away from chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants due to their harmful effects on the ozone layer. Hydrofluorocarbons (HFCs) were widely adopted as alternatives, but they have a high GWP and contribute to global warming. As a result, there has been an increasing emphasis on the development and use of environmentally friendly refrigerants, such as hydrofluoroolefins (HFOs), natural refrigerants (such as carbon dioxide, ammonia, and hydrocarbons), and other low-GWP options.