Numerical Investigation of an Absorption-Diffusion Cooling Machine Using C3H8/C9H20 as Binary Working Fluid étude numérique d’une machine frigorifique à absorption-diffusion utilisant le couple C3H8/C9H20

This paper is concerned with the analysis and the simulation of a heat-driven absorption-diffusion cooling machine which can operate with low-grade heat sources. The simplified configuration of the heat-powered absorption-diffusion refrigerating machine considered in this study is based on the Platen-Munters single pressure refrigerators principle [Platen B.C.V. and Munters C.G. (1928) Refrigerator, US Patent 1, 685-764J. Three working fluids are used, nonane as an absorbent, propane as a refrigerant and hydrogen as the inert auxiliary gas. The designed cooling capacity of the machine is 1 kW which is suitable for a domestic use for refrigeration purposes. We restricted the maximum temperature of the driving heat supplied to the generator to 130 °C, a temperature achievable with evacuated-tube solar collectors. The simulations are carried out using a commercially available flow sheeting software with the PengRobinson equation of state as property prediction method. In this paper, we analyze the heat and mass transfer characteristics in all relevant machine components (absorber, condenser, generator and solution heat exchangers). The simulations results allow determining the values of different parameters of the systems such as the refrigerant and the solvent temperatures in various points of the machine, the liquid and the vapor flow rates and compositions. The system performances were parametrically analyzed using the flow sheeting software. Performance characteristics were determined for a wide range of operating conditions allowing investigating and evaluating the effect of various design parameters. Ce papier est consacré à l’étude et l’analyse d’une machine frigorifique à absorption-diffusion. La machine est actionnée grace à une source de chaleur de température modérée. La configuration et le principe de fonctionnement de l’appareil obéissent au modèle de Platen Munters [Platen B.C.V. and Munters C.G. (1928) Refrigerator, US Patent 1, 685-764]. Le fluide de travail utilisé est le binaire propane/n-nonane, le propane étant le réfrigérant et le n-nonane, l’absorbant. L’hydrogène est utilisé comme gaz inerte, égaliseur de pression. La machine est con ue pour une production frigorifique de 1 kW. La température maximale de la source de chaleur est fixée à 130 °C, une température qu’on pourrait atteindre aisément grace à des capteurs solaires à tubes sous vide. Les simulations sont effectuées en utilisant un logiciel commercial de fiowsheeting. L’équation d’état de Peng-Robinson est le modèle thermodynamique utilisé. Nous analysons dans cet article les