Thermodynamic study of working fluid pairs for an absorption refrigeration process

Vapor-absorption refrigeration technology has received growing attention in the past years for its numerous advantages especially in connection with energy efficiency. In this technology the pressure variations are related to absorption/desorption cycles of the refrigerant in the absorbing solution. Our goal is to explore a radically different path regarding the search of new natural refrigerant/absorbent pairs. To limit the environmental impact of the working fluid pairs, the natural refrigerant investigated is carbon dioxide (CO2) and the absorbent is a bio-based solvent (BBS). In order to improve and modify the vapor absorption process, one must know the thermodynamic and volumetric properties of the working fluids since they highly influence the performance of the absorption cycle. In the absorber and generator, enthalpy of solution and vapor equilibrium data are the major process variables. The knowledge of density is also important. This work presents the energetic and volumetric properties determined experimentally of {CO2 + BBS} system using four different absorbents namely propylene carbonate, anisole, γ-valerolactone, and cyrene. Comparisons between our experimental data and literature data confirm the accuracy of our measurements and its capacity to fit thermodynamic models