külmaagenti

Külmaagenti, often translated as "cold agent" or "refrigerant," refers to a substance that is used in a refrigeration cycle to absorb heat from a low-temperature reservoir and transfer it to a high-temperature reservoir. These substances are the working fluids in refrigeration and air conditioning systems. They undergo phase changes, typically from liquid to gas and back again, to facilitate the transfer of thermal energy.

The process begins with the liquid refrigerant being expanded through a throttling valve, causing a significant drop in pressure and temperature. This cold, low-pressure liquid then flows through an evaporator, where it absorbs heat from the space or substance being cooled. As it absorbs heat, the refrigerant boils and turns into a low-pressure gas. This gas then enters a compressor, which increases its pressure and temperature. The hot, high-pressure gas then flows into a condenser, where it releases heat to the surrounding environment, typically air or water, and condenses back into a high-pressure liquid. This liquid then returns to the expansion valve, completing the cycle.

Common types of külmaagenti have included chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). However, due to environmental concerns, particularly their impact on ozone depletion and global warming, many of these have been phased out or are being phased out under international agreements like the Montreal Protocol and Kigali Amendment. Newer refrigerants, such as hydrofluoroolefins (HFOs) and natural refrigerants like ammonia, carbon dioxide, and hydrocarbons, are being developed and adopted for their lower environmental impact. The choice of külmaagenti depends on the specific application, required operating temperatures, safety considerations, and environmental regulations.