The use of CO2 as a refrigerant
In recent years, the prospects of CO2 as a refrigerant, has increased markedly. Carbon dioxide is among the fewest refrigerants for refrigeration systems that is relevant from the perspective of effective application and secure environment. The use of conventional refrigerants is limited by various regulations, and there is a tendency worldwide to tighten them. In this regard, natural refrigerants are increasingly used.
The initiative to return to the use of CO2 in refrigeration belongs to the Scandinavian countries, where laws severely limit the use of HFC and HCFC refrigerants. Ammonia has been traditionally used as the refrigerant for industrial systems, but its amount in the system is limited. This is not a problem for the plants operating at high and medium temperatures (up to -15 / -25 °C), since the amount of ammonia is reduced using a secondary coolant. For lower temperatures the use of secondary coolants is inefficient given the huge losses due to the temperature difference, in this case CO2 is being used