The compressed vapor then passes through a heat exchanger called the condenser where it releases heat thereby lowering its temperature and condensing to the liquid phase. After passing through the restrictor, the fluid in liquid phase then encounters very low pressure and subsequently evaporates inside a second heat exchanger called the evaporator. The fluid in gas phase in the evaporator then flows to the compressor to complete a cycle. The working fluid or refrigerant accepts heat while in the evaporator and rejects heat while in the condenser. Because of their relatively low density, hydrocarbons put less load on the compressor and makes the system more energy efficient and last longer.
Hydrocarbons are drop-in substitutes for chemical refrigerants.
No changing of components like lubricating oil and filter-drier is necessary. The flammability risk can be managed. Their use have resurged because of the two global environmental problems of Ozone Layer Depletion and Climate Change.