As I understand it, there are 5 key factors that determine the performance potential of a refrigerant gas:

  1. Vapor density
  2. Enthalpy of vaporization
  3. Thermal Conductivity
  4. Critical temperature
  5. Specific heat

What are the relevant equations or calculations to weigh these factors? In other words, if we consider the following performance metrics:

  1. amount of energy required to perform a specific amount of cooling
  2. speed at which cooling take place
  3. pressure required

How can I relate these 3 metrics to the 5 molecular characteristics above? Note that the answer is complex because, for example, item #1 above is a curve. For example, in other words the amount of energy required may not be constant for different rates of cooling (#2).

(Note that in this analysis I am ignoring safety issues, long-term maintenance issues like corrosion and leak tendency, and secondary performance issues, like dielectric strength; I am only considering primary performance.)

  • $\begingroup$ Surely refrigerants are chosen that match the required working temperatures? $\endgroup$
    – Solar Mike
    Jul 21, 2017 at 7:19

1 Answer 1


To calculate the performance use this calculator , easy and fast to use , its free https://www.irc.wisc.edu/properties/

  • $\begingroup$ Does this calculator give the 3 answers required? $\endgroup$
    – Solar Mike
    Jul 22, 2017 at 9:23
  • $\begingroup$ it gives you all these except the two you used for input: Molar Weight: Triple Point Temperature: Normal Boiling Point: Gas Phase Dipole at NBP: Acentric Factor: Critical Temperature: Critical Pressure: Critical Density: Gas Constant: Temperature: Pressure: Density: Volume: Quality: Internal Energy: Enthalpy: Entropy: Isochoric Heat Capacity: Isobaric Heat Capacity: Surface Tension: Thermal Expansion: Sound Speed: Fugacity: Viscosity: Thermal Conductivity: Prandtl Number: Helmholtz Energy: Gibbs Free Energy: $\endgroup$
    – J.oe
    Jul 22, 2017 at 9:35
  • $\begingroup$ But not the amount of energy (as asked), speed of cooling (as asked) or the pressure required, again as asked, so does not answer the question. $\endgroup$
    – Solar Mike
    Jul 22, 2017 at 10:03

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