Requirements For Refrigerant Properties

(1) Having excellent thermodynamic properties to achieve high cycle efficiency when operating within a given temperature range. The specific requirements are: the critical temperature is higher than the condensation temperature, the saturation pressure corresponding to the condensation temperature should not be too high, the standard boiling point is low, the fluid specific heat capacity is small, the adiabatic index is low, and the unit volume heating capacity is large. [2]
(2) The specific requirements for excellent thermophysical properties are: higher heat transfer coefficient, lower viscosity, and lower density.
(3) Having good chemical stability requires the working fluid to have good chemical stability at high temperatures, ensuring that the working fluid does not decompose at the highest working temperature.
(4) Good solubility with lubricating oil
(5) The safety working fluid should be non-toxic, non irritating, non flammable, and explosive.
(6) Good electrical insulation
(7) Economic requirements require low working fluid and easy access.
(8) Environmental friendliness requires the ozone depletion potential (ODP) and global warming potential (GWP) of working fluids to be as small as possible to reduce damage to the atmospheric ozone layer and cause global climate change. [3]
Organic compounds
(1) Nomenclature of halogenated alkanes:
Molecular formula: CmHnFxCly (n+x+y=2m+2)
Number: R (m-1) (n+1) x (a, b...)
Example:
Difluorochloromethane (CHClF2) - R22
Tetrafluoroethane (CF3 CH2F) - R134a
(2) Alkanes:
Number: Same as halogenated hydrocarbon numbering method
Example: Ethane (C2H6) - R170
Propane (C3H8) - R290
N-butane (C4H10) - R600, isobutane - R600a
(3) Alkenes
Number: R1+halogenated hydrocarbon numbering method
Example:
Ethylene (C2H4) - R1150
Propylene (C3H6) - R1270
(4) Suffix
① Add a letter code based on the difference in the sum of atomic weights of substituents on carbon atoms. For those with the smallest difference in the sum of atomic weights of substituents, do not need to add a letter code. For those with the second smallest difference, add "a", followed by "b", and so on.
② Chemical composition
A - CCl2-, b - CCLF -, c - CF2-, d - CHCl -, e - CHF -, f - CH2--
X - CCl -, y - CF -, z - CH-