It will be useful to remind ourselves of the requirements for a fluid used as a refrigerant.
• A high density of suction gas
• Non-corrosive, non-toxic and non-flammable
• Critical temperature and triple point outside the working range
• Compatibility with component materials and lubricating oil
• Reasonable working pressures (not too high, or below atmospheric pressure)
• High dielectric strength (for compressors with integral motors)
• Low cost
• Ease of leak detection
• Environmentally friendly
No single fluid has all these properties, and meets the new environmental requirements, but this chapter will show the developments that are taking place in influencing the selection and choice of a refrigerant.