Thermodynamic screening of alternative refrigerants for R290 and R600a

Due to Regulation EU 517/2014 (F-Gas), the use of refrigerants with GWP higher than 150 was limited from 2015 on in small capacity refrigeration systems in Europe. Although refrigerants that dominate are R600a and R290 nowadays, which are classified as A3 by ASHRAE 34, literature points out that some refrigerant mixtures exist that could offer benefits from the point of view of COP and VCC, especially mixtures of hydrocarbons.This study tries to identify possible mixtures which could be used as alternatives to pure hydrocarbons, with the aim to increase the energetic behaviour of the systems and, if possible, to reduce the flammability characteristics. A thermodynamic screening of refrigerant mixtures (with the base refrigerants R290, R600a, R600, R1270, R152a, R32, R1234yf, R1234ze(E), R1233zd, R744 and R134a) is presented and detailed for two typologies of systems: single-stage systems with adiabatic capillary tube and single-stage systems with non-adiabatic capillary tube. The screening identifies the most promising refrigerant mixtures that will be tested later in experimental systems. Keywords: Hydrocarbons, Refrigerant, Stand-alone systems, Energy efficiency