Sistema de refrigeração integrado aplicado a um supermercado utilizando CO2

Abstract

It has been known in recent years that synthetic refrigerants (CFCs, HCFCs and HFCs), widely used and diffused around the world, are one of the main causes of worsening global warming and the increase of ozone layer depletion. Faced with this, with a growing concern about the damage and environmental impacts caused by humans, the present work evaluated the feasibility of using a refrigeration system in a supermarket using CO2 as refrigerant, comparing in terms of efficiency three different forms of refrigeration cycle construction. A general analysis on the theme was performed, addressing the motivations, the foundations and building a theoretical basis for the elaboration of the cycles and results. In addition, the subject was approached in an applied way, using the theory for the actual design of different cycles: one using HFC fluid R134a, another applying CO2 in the subcritical condition (cascade, with R717), and another with CO2 in the transcritical condition, all of them facing the reality of a medium-large supermarket in the city of Uberlândia, Minas Gerais. In this, it was developed the layout of a supermarket, the calculation of its thermal load, the designs of the steam compression refrigeration cycles in different conditions meeting the requirements and a subsequent comparative analysis between the cycles, exposing the appropriate conclusions. Finally, a selection of the main equipment that makes up a cooling system for the cycle that was most efficient was outlined.