Thermodynamic properties of R290 and R1270

R290 has favourable thermodynamic properties and a low energy requirement during compression. The pressure levels and volumetric refrigerating capacity are similar to values of R22 (Vapour pressure curves of R290 and R1270 compared with R22 and HFC refrigerants und Volumetric refrigerating capacity of various refrigerants compared with R290 at identical suction gas volume flows), but there are larger deviations for enthalpy, density, mass flow and isentropic exponent (allowable temperatures). There are even larger differences with respect to R404A/R507A, R134a and R410A.

R1270 also has favourable thermodynamic properties and a low energy requirement during compression. However, the pressure levels and volumetric refrigerating capacity are higher than for R290 and R22, Vapour pressure curves of R290 and R1270 compared with R22 and HFC refrigerants und Volumetric refrigerating capacity of various refrigerants compared with R290 at identical suction gas volume flows.

• High enthalpy of evaporation:
  At -10/40°C about 1.7 times R22 and 2.5 times R404A/R507A.
• Low refrigerant mass flow:
  At identical refrigerating capacities approx. 55-60% compared with R22 and approx. 40% compared with R404A/R507A (Mass flow of various refrigerants compared with R290 at identical refrigerating capacities).
• Low vapour density (approx. 50% compared with R22 at 20°C and 1013 mbar) and liquid density (approx. 40% at 45°C compared with R22), resulting in low pressure losses in pipelines and heat exchangers.
• Good heat transfer values, among other things, due to intense boiling and good oil solubility.
• Extremely low discharge gas and oil temperatures for R290 (isentropic exponent R290 = 1.13 / R22 = 1.18).
• Lower discharge gas and oil temperatures of R1270 than R22 (isentropic exponent R1270 = 1.15 / R22 = 1.18), but higher than R404A/R507A.
• At low suction gas superheat and/or operation at small pressure ratios, there is a risk of increased refrigerant solution in the oil.

• High superheat enthalpy, relative to the change in volume. With increasing useful superheat, increasing volumetric refrigerating capacity
• High critical temperature (R290: 96.7°C, R1270: 91.1°C), but for R1270 slightly below R22.