Thermophysical Properties of Refrigerant Systems

Thermophysical properties of refrigerant systems encompass a broad set of measurable physical and thermodynamic parameters that dictate the performance and environmental impact of cooling cycles. These include precise characterisations of density, vapour pressure, heat capacity, thermal conductivity, viscosity, speed of sound and critical parameters across temperature and pressure ranges relevant to vapour–compression and other refrigeration technologies. Accurate data underpin the design and optimisation of heat exchangers and compressors, inform cycle simulations and ensure safety and efficiency. The transition to low global warming potential fluids—such as hydrofluoroolefins and natural refrigerants—has driven renewed research into both pure compounds and binary or ternary blends. Experimental methods, molecular simulation and advanced equations of state converge to refine predictive models and support regulatory compliance under the Kigali Amendment and F-gas regulations. Together, these efforts aim to balance energy efficiency, flammability limits, material compatibility and environmental stewardship in global refrigeration and air-conditioning applications.

Research from Nature Portfolio

Recent studies have demonstrated that only a limited number of pure fluids satisfy the combined criteria of chemical stability, thermodynamic performance, environmental compatibility and safety, with slight flammability emerging as a common trait among viable low-GWP candidates. Through database screening and system-level simulations of small-scale air-conditioning units, researchers have shown that real-world hardware constraints alter the classical efficiency-capacity trade-off, with peak performance achieved at relatively high volumetric refrigeration capacities. This work establishes foundational guidelines for the selection of replacement refrigerants that optimise both energy efficiency and environmental impact.

Thermophysical Properties of Refrigerant Systems publication trend

The graph below shows the total number of articles in thermophysical properties of refrigerant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Thermophysical properties: Physical and thermodynamic characteristics of fluids, including density, viscosity, thermal conductivity and heat capacity.

Global warming potential (GWP): A relative measure of how much heat a greenhouse gas traps in the atmosphere over a specified time frame compared to CO₂.

Vapour–liquid equilibrium (VLE): The condition in which a liquid and its vapour phase are in thermodynamic equilibrium at a given temperature and pressure.

Equation of state (EoS): A mathematical model relating pressure, volume and temperature of a fluid, often used to predict phase behaviour.

Critical point: The temperature and pressure at which the liquid and vapour phases of a substance become indistinguishable.

References

1. Limited options for low-global-warming-potential refrigerants. Nature Communications (2017).
2. Assessment of Low Global Warming Potential Refrigerants for Drop-In Replacement by Connecting their Molecular Features to Their Performance. ACS Sustainable Chemistry & Engineering (2021).
3. Thermophysical Properties of Low GWP Refrigerants: An Update. International Journal of Thermophysics (2023).
4. Isothermal (Vapour + Liquid) Equilibrium Measurements and Correlation of the Binary Mixture {3,3,3-Trifluoropropene (HFO-1243zf) + 2,3,3,3-tetrafluoropropene (HFO-1234yf)} at Temperatures from 283.15 K to 323.15 K. International Journal of Thermophysics (2023).
5. Predictive Molecular Simulation Studies on the Vapor–Liquid Equilibria of 10 Binary Mixtures Containing Different Hydrofluoroolefins. Journal of Chemical & Engineering Data (2024).