Numerical Investigation of an Absorption-Diffusion Cooling Machine Using C 3

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

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 grâce 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 conçue 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 grâce 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 transferts thermiques et massiques dans les différents composants de l’appareil (absorbeur, condenseur, évaporateur, générateur et échangeurs de chaleur). Les résultats des simulations permettent de déterminer les valeurs des différentes grandeurs caractérisant le fonctionnement de la machine telles que les débits, les compositions et les températures. Une analyse paramétrique a été menée pour évaluer les performances de la machine pour un large éventail des conditions de fonctionnement

Numerical Investigation of an Absorption-Diffusion Cooling Machine Using C

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

Multi-objective optimization of sub-assemblies design towards static mechanical equilibrium of sodium-cooled fast reactor core

International audienceIn the framework of Sodium-cooled Fast Reactors, core design studies are performed at CEA. A new methodology based on core multi-objective optimization is proposed taking into account the geometrical uncertainties on sub-assemblies regarding manufacturing tolerances for core static mechanical equilibrium analysis. This methodology relies on feedback from past reactors, especially PHENIX and SUPERPHENIX. As an example, the optimization is performed on a reduced number of parameters (distance across flats of pads, natural core restraint by reflectors sub-assemblies, pads axial position and stiffness).The thermal-mechanics core HARMONIE V2 code and the uncertainties URANIE platform are applied to define a first set of optimal features of the sub-assemblies. The core behaviour is analysed during nominal conditions, fuel handling operations and unprotected transients (i.e. with complete failure of all automatic shutdown systems).First results tend towards to give priority to high pads flexibility in order to minimise friction between sub-assemblies during handling operations. Pads on the whole of sub-assemblies, including reflectors, should be preferred for core restraint requirements. The effect of pads axial position over the core static mechanical equilibrium is limited, but pads located close to the top of fuel pins favour the pads effect during an unprotected transient