Low-temperature-level mixed refrigerant suitable for two-stage multiplex refrigerating system

Abstract

The invention relates to mixing refrigerant used in the low temperature stage of the two stage cascade system refrigeration system. The mixing refrigerant includes ethane, full fluorine ethane or / and fluoroform. It can be made up of ethane whose molar concentration is 25%-95% and full fluorine ethane whose is the rest. And it also can be made up of ethane whose is 45%-75% and fluoroform whose is the rest. It also can include all three of them whose respectively is 25%-90%, 5%-60%, and the rest. Its advantages are that it has high efficiency and evaporating pressure; its ODP is zero; the GWP is greatly reduced compared with the R503 and R5088; and it has good inter-solubility with lubricating oil.

Description

technical field [0001] The invention relates to a mixed refrigerant, in particular to a mixed refrigerant suitable for a low-temperature stage in a two-stage cascade refrigeration system. Background technique [0002] With the development of society and science and technology, there is an increasing demand for cooling temperatures around -80°C. The refrigeration in this temperature zone is mainly used for active storage of biological materials, low-temperature preservation of deep-sea fish, etc. The minimum effective refrigeration temperature of a single-stage vapor compression refrigeration cycle can generally only reach about -40°C, but when it actually reaches -35°C, the refrigeration efficiency will deteriorate due to low evaporation pressure. To achieve lower refrigeration temperatures, a two-stage cascade refrigeration cycle becomes an option. The basic principle of cascade refrigeration is to use a high-temperature stage refrigeration system to cool a low-temperatur...

AI Technical Summary

Problems solved by technology

However, R290 or R600a and lubricating oil have very good solubility characteristics, so a large amount of R290 and R600a will dissolve in the lubricating oil, which may lead to a decrease in the lubricating properties of the compressor

In addition, due to the increase of high-boiling-point components in the circulating working fluid, the low-temperature refrigeration performance of the refrigerant will decrease.

[0004] Therefore, the existing low-temperature working fluids used in cascade refrigeration systems either have the problem of ozone layer destruction, or have problems such as large greenhouse effect and poor miscibility with lubricating oil.

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