A refrigerant is simply a substance used in an HVAC system to transfer heat from one location to another. It is the required component for the refrigeration cycle.

Refrigerants are often a hot button issue because they have a history of damaging the ozone, contributing to climate change, as well as potential toxicity.

A license is typically required to supply a refrigerant or to recover it.

Refrigerants are generally used in the plant side of an energy model. Interestingly, a modeler does not always have to define the refrigerant, as the impact of a refrigerant will be reflected an a plants efficiency and default design operating temperatures.