Propylene (R1270) as an alternative to propane

For some time there has been increasing interest in using propylene (propene) as a substitute for R22 or HFC. Due to its higher volumetric refrigerating capacity and lower boiling temperature (compared to R290), applications in medium and low temperature systems are of particular interest, e.g. liquid chillers. On the other hand, higher pressure levels (> 20%) and discharge gas temperatures have to be taken into consideration, restricting the possible application range.

Material compatibility is comparable to propane, as is the choice of lubricants.
Propylene is also easily inflammable and belongs to the safety group A3. The same safety regulations are therefore to be observed as with propane (R290 as alternative refrigerant).

Due to the chemical double bond, propylene reacts quite easily, risking polymerization at high pressure and temperature levels. However, tests by hydrocarbon manufacturers and stability tests in real applications show practically no reactivity in refrigeration systems. Doubts have occasionally been voiced in literature regarding possible carcinogenic effects of propylene. These assumptions have been disproved by appropriate studies.