-80°C Evaporating Temperature
There are several applications where the evaporating temperature needs to reach extremely low value, like pharmaceutical applications, climatic chambers, etc…
Due to the extremely high pressure ratio between condensing temperature and evaporating temperature, a cascade system is needed to divide the compression in two refrigeration systems where the gas in the LT cycle condensates in the evaporator of the MT cycle.
Main refrigerants used for this kind of application are R23 (GWP 14800) and R508B (GWP 13396), which compared to R23 offers a lower discharge temperature. Applications with these refrigerants are exclusively used below -50° and are exempted from the EU F-GAS.
Nevertheless, other low GWP options are under study to achieve eco-friendly solutions. R170 (GWP 6) is a promising gas with the constraint of the flammability since it is a hydrocarbon with A3 safety class. R469A (GWP 1357) is a mixture of R410A and R744, A1 safety class, compatible with POE lubricants and with similar pressure levels of R23 but with the significant drawback of 17 K temperature glide at 1 bar.
Dorin compressors have been used since decades with R23 allowing excellent performance and long-term reliability with countless systems installed worldwide in several applications, from the 2 cylinders H11 range for small systems to the Tandem H7, giving up to 90 kW @-80°C.
Source : https://dorin100.blogspot.com/2020/11/80c-evaporating-temperature.html