Thermodynamic analysis of an absorption refrigeration cycle operating with the working fluid pair (CO₂-propylene carbonate).

With the increasing energy demand for cooling and in the search for alternatives to compression refrigeration machines, vapor absorption refrigeration technology is emerging as a promising solution. However, the traditional working fluids used in these machines (based on H2O and NH3 as refrigerants) present some disadvantages such as corrosion, low compactness, toxicity, and crystallization risks. To overcome these disadvantages, this study considers using carbon dioxide (CO₂) as refrigerant combined with a bio-based solvent, namely propylene carbonate. Indeed, based on new experimental vapor-liquid equilibria VLE data and taking into account the available literature data, propylene carbonate (PC) was identified as an interesting absorbent for CO₂. The experimental data obtained for the CO₂-PC mixture, combined with those from the literature, were used to develop an appropriate thermodynamic model to finally assess the performance of a single-stage absorption chiller with this working fluid pair.