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Abstract(s)
Os fluidos frigorigéneos naturais têm adquirido crescente destaque, impulsionados pela preocupação global com as mudanças climáticas e a necessidade de mitigar o impacto ambiental das atividades humanas. A consciência dos danos causados pelo setor da refrigeração e frigorigéneos sintéticos, aliado às regulamentações ambientais, têm sublinhado a importância de adotar alternativas mais sustentáveis. Entre essas alternativas destacam-se, assim, os frigorigéneos naturais, como o amoníaco e o dióxido de carbono. Cada um dos quais possui não só características vantajosas, como também inconvenientes próprios, tornando crucial avaliar comparativamente as duas opções. A avaliação baseia-se em parâmetros como as temperaturas de funcionamento, coeficiente de desempenho e custo, proporcionando uma compreensão mais detalhada do comportamento de ambos os frigorigéneos nos sistemas frigoríficos em que são aplicados. O objetivo central deste trabalho é, então, realizar uma análise comparativa, caracterizando o desempenho e funcionamento de bombas de calor de pequena escala e de sistemas de armazenamento refrigerado utilizando frigorigéneos naturais, nomeadamente, NH3 e CO2 e, a partir dessa análise, determinar o sistema de refrigeração e
frigorigéneo mais apropriados para essas aplicações. Foi concluído que o frigorigéneo mais adequado para o sistema de refrigeração de uma bomba de calor de pequena escala consiste no CO2 transcrítico, enquanto o armazenamento refrigerado depreende os sistemas de compressão de amoníaco como mais adequados.
Natural refrigerants have gained increasing recognition, driven by global concern about climate change and the need to mitigate the environmental impact of human activities. Awareness of the damage caused by the refrigeration sector and synthetic refrigerants, coupled with environmental regulations, has emphasised the importance of adopting more sustainable alternatives. These alternatives include natural refrigerants such as ammonia and carbon dioxide. Each of these has its own advantages and disadvantages, making it crucial to evaluate the two options comparatively. The evaluation is based on parameters such as operating temperatures, coefficient of performance and cost, providing a more detailed understanding of the behaviour of both refrigerants in the refrigeration systems in which they are applied. The main aim of this work is therefore to carry out a comparative analysis, characterising the performance and operation of small-scale heat pumps and refrigerated storage systems using natural refrigerants, namely NH3 and CO2, and from this analysis to determine the most appropriate refrigeration system and refrigerant for such applications. It was concluded that the most suitable refrigerant for the refrigeration system of a small-scale heat pump is transcritical CO2, while ammonia compression systems are more appropriate for refrigerated storage.
Natural refrigerants have gained increasing recognition, driven by global concern about climate change and the need to mitigate the environmental impact of human activities. Awareness of the damage caused by the refrigeration sector and synthetic refrigerants, coupled with environmental regulations, has emphasised the importance of adopting more sustainable alternatives. These alternatives include natural refrigerants such as ammonia and carbon dioxide. Each of these has its own advantages and disadvantages, making it crucial to evaluate the two options comparatively. The evaluation is based on parameters such as operating temperatures, coefficient of performance and cost, providing a more detailed understanding of the behaviour of both refrigerants in the refrigeration systems in which they are applied. The main aim of this work is therefore to carry out a comparative analysis, characterising the performance and operation of small-scale heat pumps and refrigerated storage systems using natural refrigerants, namely NH3 and CO2, and from this analysis to determine the most appropriate refrigeration system and refrigerant for such applications. It was concluded that the most suitable refrigerant for the refrigeration system of a small-scale heat pump is transcritical CO2, while ammonia compression systems are more appropriate for refrigerated storage.
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Keywords
Refrigeration Natural refrigerants Ammonia CO2 Refrigeration system Refrigeração Fluidos frigorigéneos naturais Amoníaco Sistema frigorífico Refrigeration Natural refrigerants Refrigeration system