Computational fluid dynamics assisted exergy analysis of a mini refrigerator with absorption cooling

In these days when the importance of energy is increasing, it is of great importance to improve the performance of cooling systems. As of 2021, within the scope of the new energy regulation published by the European Union (EU), manufacturers are encouraged to make improvements in terms of energy efficiency. Although the energy consumption values of absorption cooling systems are not very good, they are seen as one of the priority cooling systems, especially in the tourism sector, due to their quiet operation and the use of environmentally friendly fluids compared to compressor products. In this context, thermodynamic analysis of a single-stage diffusion-absorption minibar refrigerator was carried out. Ammonia was used as the refrigerant fluid, water as the absorbent fluid, helium gas as the pressure balancer and electrical resistance as the power source in the minibar refrigerator considered. In the study, the minibar refrigerator was arranged as an experimental setup for thermodynamic analysis and temperature and pressure measurements were made from different points of the minibar refrigerator. Experimental measurements were carried out both in the minibar cooling cabinet and in the absorption cooling cycle. The exergy analysis of the considered minibar was supported by the Computational Fluid Dynamics (CFD) analysis. In addition to the energy and exergy analysis performed with experimental measurements, the entropy production of the cooled cabin was calculated by CFD analysis. CFD methods applied in this thesis study were verified by temperature measurements. The mean absolute percent error (MAE) between the experimental temperature measurements of the cooled cabinet and the CFD simulation temperatures was found to be 3.4%. According to the results of the analysis, it was determined that the highest heat transfer rate occurred in the separator with 27.2 W. In this thesis study, it was concluded that the highest exergy destruction in the absorbed minibar was in the heat exchanger with 9.02 W. The exergy efficiency of the absorb minibar is 0.719; The Efficiency Effect Coefficient (COP) was found to be 0.13.