Following a qualification program, compressor specialist Bitzer has approved R1234yf and R1234ze(E) HFO refrigerants for use in its CSH and CSW screw compressors. The two alternatives to R134a have a global warming potential (GWP) of less than 10. The HFO/HFC blends R513A and R450A also are approved for the CSH and CSW Series.

The requirements stipulated by the European Union’s F-gas Regulation No. 517/2014 challenged refrigeration compressors as well as system owners and operators, says Bitzer. To meet the phase-down objectives, alternative refrigerants such as hydrofluoroolefins (HFOs) will have to be used in the future. The volumetric refrigerating capacity and pressure levels of R1234yf are comparable with those of R134a; the capacity figures and pressure levels of R1234ze(E) are around 20 to 25 percent lower.

Bitzer subjected the R1234yf and R1234ze(E) refrigerants in this group to intensive testing, and the compressors performed well with both in all of the tests and laboratory experiments. The tested compressors achieved nearly identical isentropic efficiency values with R1234yf and R1234ze(E) as with R134a. Due to differences in the thermodynamic properties, the COP measurement results are, in some cases, slightly lower.

The compressor maker’s CSH and CSW compact screw compressors can be used with the economizer circuit to increase refrigerating capacity and efficiency. They are fitted with dual-capacity control and can be adjusted infinitely or according to scale.

Series CSW is suitable for use in liquid chillers operated at low condensing temperatures in systems with water-cooled condensers, process cooling, and systems with air cooled condensers operating under moderate climatic conditions. Series CSH compressors can be used in air-cooled liquid chillers as well as comfort air conditioning and heat pumps. Learn more at