Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
ENERGY AND EXERGO-ECOLOGICAL ANALYSIS OF A REFRIGERATION SYSTEM USING R290 AND R1234YF AS A REPLACEMENT FOR R134A
Submission Author:
Cleison Henrique de Paula , MG
Co-Authors:
Cleison Henrique de Paula, Willian Moreira Duarte, THIAGO TORRES MARTINS ROCHA, Raphael Nunes Nunes de Oliveira, Antônio Maia
Presenter: Cleison Henrique de Paula
doi://10.26678/ABCM.COBEM2021.COB2021-0191
Abstract
Since the 1990s, vapor compression refrigeration systems operating with HFCs have been widely used in domestic and commercial refrigeration, mainly the R134a. Over the years, it was observed that these systems have high energy consumption and produce a relevant environmental impact due to high GWP of the refrigerant used. Thus, in recent years, the international community has been establishing protocols and amendments to accelerate the elimination of these non-ecological refrigerants (high GWP). In view of this need, several researches have carried out works oriented to develop energy-efficient refrigeration systems that operate with ecological refrigerants (low GWP), such as R290 and R1234yf. In most of these works, mathematical models were used to improve the performance of the new systems and to evaluate which is the most appropriate ecological refrigerant to replace the old systems. The main goal of this paper is to propose a steady-state model to design a vapor compression refrigeration system that simultaneously produces chilled water (5°C) for an indirect expansion air-conditioning system and hot water (50°C) for a restaurant to clean the cutlery, plates and pans. The proposed model uses volumetric and global efficiency curve obtained from commercial compressors available in the market to describe the compression process more realistically and an optimization method (Nelder-Mead Simplex) to design a system with a compact geometric structure and determine the thermodynamic condition in which it operates with the best performance. The ecological analysis was performed based on TEWI (total equivalent warming impact) and ECOP (ecological coefficient), while the energy and exergy analysis were performed based on COP and Exergy Efficiency. According to the optimization procedure, all systems achieved higher performance for an evaporation temperature of -3°C and condensation temperature of 50 °C. In addition, the refrigerant diameter obtained was 6 mm while the water diameter obtained was 12 mm in both evaporator and condenser in all evaluated systems. The energy and exergo-ecological analysis indicates that the system with R290 is the only system with higher energy, exergy and ecological performance than the system operating with R134a. Therefore, among the evaluated systems, the system with R290 is the only one suitable to replace the system with R134a.
Keywords
COP, ECOP, TEWI, Exergy efficiency, Vapor Compression refrigeration System
