Lower GWP blends in Bitzer compressors
GERMANY: Bitzer has produced an information sheet for those considering using some of the new lower GWP refrigerants and blends with its compressors.
Many of the new lower GWP refrigerants are mostly mixtures of common HFCs, HFOs and hydrocarbons. Bitzer lists blends with the components R32, R125, R134a, R143a, R152a, R1234yf, R1234ze(E),R290, R600 and R600a as being tested for compatibility. For several refrigerants Bitzer can deliver predicted performance data upon request.
Provided the blends use only the components listed in table 1 and the vapour pressure curves are not below those of R134a and not above those of R404A or R407F the following Bitzer compressors are said to be suitable for use in field test installations:
Ecoline semi-hermetic reciprocating compressors/ POE oil
HS semi-hermetic screw compressors/ POE oil
CSH semi-hermetic compact screw compressors/ POE oil
CSW semi-hermetic compact screw compressors /POE oil
The paper warns that as many of the new R404A or R22 replacement refrigerant blends have a significant temperature glide of 4 to 7K, this can, depending on the system and heat exchanger design, lead to different evaporating and condensation temperatures compared to the refrigerants they are designed to replace. As a result, the operating conditions of the compressor can move, resulting in need for additional cooling
The full document is available for download here.