Avaliação do comportamento energético e exergético de um sistema de refrigeração por compressão de vapor.

Abstract

This research presents energetic and exergetic analysis of a water refrigeration unit, called Chiller. The Chiller under study performs the thermodynamic cycle of the refrigeration with the assistance of a mechanical compressor, usually triggered by an electric motor, in order to increase the pressure in a certain stage on the thermodynamic cycle of the system, which generates high energy consumption. However, with the advance of the technology, every day emergs new types of compressors that have lowest energy consumption and improves the performance of the unit as a whole. The purpose of this work is to evaluate both e nergetic and exergetic behavior, of a chiller that provides cold water and works with a screw type compressor, based on the first and second laws of thermodynamics . This study was based on the actual behavior of a steam compression chiller from a mall in the city of João Pessoa-PB. Through numerical simulation, it was possible to evaluate the behavior of the equipment with the change of some of the normal parameters of work, as condensation and evaporation pressures, condensation and evaporation temperature and refrigerant fluid. In this study, the performance of the equipment data is presented as a function of the evaporator and compressor pressures, the evaporation temperature and other parameters. The results of the simulations, that were realized with support of software EES, showed that the unit performance was improved by decreasing the pressure variation between condenser and the evaporator and also has proved that the energetic and exergetic efficiences are increased by raising the evaporation temperature and a reduction happens by increasing the condensation temperature.