Estudo experimental e modelo de simulação para avaliação do retrofit do R-22 em unidades de climatização do tipo split

• Ano de defesa: 2024
• Autor(a) principal: Leonardo Victor Silva Martins
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ENG - DEPARTAMENTO DE ENGENHARIA MECÂNICA; Programa de Pós-Graduação em Engenharia Mecanica; UFMG
• Palavras-chave em Português: Sistema de refrigeração; Modelo matemático; R-22; R-444b; R-454c; Sustentabilidade; Energia - Consumo; Meio ambiente; Refrigeração; Modelos matemáticos; Impacto ambiental
• Link de acesso: http://hdl.handle.net/1843/75911

Since the adoption of the Montreal Protocol in 1987, several amendments have occurred to strengthen (such as Kyoto in 1997) and even expedite goals, encouraging industries to develop refrigeration systems with lower environmental impacts by using refrigerants with low GWP (Global Warming Potential), for example. In parallel to this, there is a large fleet of refrigeration units in developing countries like Brazil, which operate with high GWP fluids like R-22, and discarding such equipment due to the obsolete refrigerant would entail significant losses not only for the owners but also for the environment. With the aim of repurposing these units, this study aimed to evaluate alternative fluids that replace current ones with as few modifications to the system as possible and without significantly compromising the performance of these sets. To achieve this, a mathematical model of a refrigeration system was developed, which was later experimentally validated for R-22. Subsequently, this model was incorporated into a thermal zone based on the environmental conditions of Belo Horizonte from December 2022 to November 2023 (one year), and the fluids R-407C, R-444B, and R-454C were compared to R- 22 through COP (Coefficient of Performance), cooling capacity, and TEWI (Total Equivalent Warming Impact), in addition to the analysis of climatic seasonality. After the analyses, it was possible to observe that R-407C has a COP and cooling capacity 6% and 3% lower than R-22, respectively, with TEWI being 5% lower than the reference. On the other hand, R-454C has a COP and cooling capacity 16% and 11% lower than R-22, respectively, but it has a total TEWI 55% lower than the reference due to its low GWP. Finally, R-444B was identified in this study as the best alternative to replace R-22 at mild temperatures, as it has a COP and cooling capacity 15% and 9% higher, respectively, and also has a TEWI 55% lower than the reference.