Estudo de ciclos de refrigeração utilizando R-744 como fluido refrigerante

Abstract

HCFCs’ fluids are the most commonly used in refrigeration cycles. However, new guidelines foresee the abandonment of such fluids for environmental reasons and the industry has again turned its attention to natural fluids, and among them, to carbon dioxide or R-744. The present work performs an energy and exergetic analysis of five transcritical refrigerant cycles using R-744 as refrigerant fluid. A code in the Engineering Equation Solver (EES) software was prepared for each cycle, simulating and optimizing them. The irreversibilities of each cycle are also calculated, in order to analyze the largest entropy generators. In addition, the optimum pressure points for fluid at the cooler inlet are determined in each cycle, thereby maximizing COP, and consequently optimizing each cycle.