Non-fluorinated refrigerants, commonly known as natural refrigerants, are substances that have been used as refrigerants since the 1950s. They cause no damage to the ozone layer and their global warming potential is zero, or practically zero. The most commonly used substances used for commercial and industrial refrigeration are ammonia (R-717), carbon dioxide (R-744) and hydrocarbons (HC), such as isobutane (R-600a), propane (R-290), ethane (R-170) and propylene (R-1270).
In some cases, their application and refrigerant charge may be more limited than fluorinated gases classed as A1, for safety reasons. This is due to their increased risk to humans as flammable and toxic substances, such as ammonia (B2L), or highly flammable substances, such as hydrocarbons (A3). However, the thermodynamic properties of hydrocarbons and ammonia are good, and they also have a low environmental impact.
The use of carbon dioxide for commercial and supermarket refrigeration began to be commonplace mostly within the Nordic countries in the EU, but thanks to advances in the technology of the related equipment, we are now also seeing it being used in Southern Europe, in much hotter countries like Spain and Portugal, where it was initially believed that it would not be viable. The main problem with carbon dioxide (CO2) is its high operating pressure, meaning it requires a greater initial investment than other solutions currently available.
The use of these substances has experienced a resurgence in recent years due to their low environmental impact, making them clear solutions for the future for many applications.