Numerical analysis and experimental studies of vapour compression refrigerating systems: special emphasis on different cycle configurations

Abstract

The aim of this work is to study the thermal behavior and fluid-dynamic systems, vapor compression refrigeration and its components (heat exchangers, expansion devices, compressors, connecting pipes, pumps and pressure vessels). Topics discussed throughout this thesis arise from the growing interest in refrigerants friendly environment as well as different types of cooling systems for vapor compression has motivated the research group of the CTTC (Centre for Heat Transfer Technology ) to carry out major research efforts as well as participate in several projects with national and European institutions. The information contained in this thesis represents a summary of work performed by the author in recent years but also includes many of the contributions made by other members of CTTC. This thesis has led to the publication of several articles in international conferences. The main achievement of this thesis was the development of a numerical tool based on several subroutines flexibility to study different cooling Systemas vapor compression. The entire digital infrastructure has been the result of attaching specific numerical resolutions of each element of the cycle with the overall resolution algorithm. The simulations have been oriented to the study of thermodynamic cycle as well as to study some relevant aspects of the elements. In addition to the numerical results has been carried out important experimental work in the CTTC facilities in order to validate numerical models. The author has been fully involved in the process of data acquisition and has collaborated in the development of the units. The thesis is structured into five chapters plus a final conclusions and future actions. The first chapter, the introduction puts the reader in regard to the problematic situation, the history of cooling and objectives. The second presents the mathematical formulation and numerical methodology used in the simulation of the different elements and all cooling systems. The third study presents the numerical code verification. The fourth focuses on the validation of models with experimental results. And finally the fifth presents a suite of parametric studies and analysis. The numerical simulation code implemented has proven to be a flexible tool as various aspects of the steam compression systems have been successfully simulated and studied. It has also proven a reliable and good level of accuracy as the numerical results have been simulated properly the various experimental data compared.