Mysite Group

A refrigerant is a specialized working fluid central to the operation of refrigeration, air conditioning, and heat pump systems. Its primary function is to absorb heat from a low-temperature environment and release it to a higher-temperature area through a continuous cycle of phase changes between liquid and vapor states. This process, governed by the principles of thermodynamics, begins in the evaporator, where the cold, low-pressure liquid refrigerant absorbs ambient heat, causing it to boil and turn into a gas. This gas is then compressed, which dramatically increases its temperature and pressure. The hot, high-pressure gas then travels to the condenser, where it releases its absorbed heat to the outside environment, cooling down and condensing back into a liquid. Finally, an expansion valve reduces its pressure and temperature, returning it to the evaporator to repeat the cycle.

The evolution of refrigerants has been marked by significant environmental and safety concerns. Early refrigerants like ammonia and sulfur dioxide were effective but toxic or flammable. The mid-20th century saw the rise of chlorofluorocarbons (CFCs), which were stable and non-toxic but were later discovered to be catastrophic for the ozone layer. Their phase-out led to hydrochlorofluorocarbons (HCFCs) and then hydrofluorocarbons (HFCs), which solved the ozone depletion problem but were found to be potent greenhouse gases with a high Global Warming Potential (GWP). The current frontier is the development of fourth-generation refrigerants, including hydrofluoroolefins (HFOs) and "natural" refrigerants like carbon dioxide (CO₂), propane (R290), and ammonia, which aim to balance efficiency with minimal environmental impact, featuring zero ozone depletion potential and a significantly lower GWP to combat climate change.