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Abstract(s)
A indústria da refrigeração apresenta um papel fulcral em diversos setores, tais como alimentar, químico e dos transportes. A grande utilização dos sistemas de refrigeração leva à sua evolução com o intuito de introduzir novas tecnologias e de as aprimorar numa vertente de menor impacto ambiental. Na atualidade as centrais frigoríficas com CO2 como fluido de trabalho no regime transcrítico são uma excelente resposta para a legislação em vigor atualmente. Como tal, a RACE (empresa de acolhimento) confrontou-se com os novos desafios do setor da refrigeração e tomou a decisão de desenvolver a sua própria linha de produtos. Inicialmente foi desenvolvida uma estrutura para uma central frigorífica a funcionar com CO2, com o objetivo de oferecer as melhores soluções de produtos aos seus clientes. Posto isto, a empresa sentiu a necessidade de otimizar a estrutura metálica da sua central frigorífica. A presente dissertação consistiu no estudo desta estrutura, através da realização de estudos estruturais implementando o Método de Elementos Finitos (MEF) ao modelo inicial da estrutura, com o objetivo de apresentar um plano de melhorias a esta central e assim desenvolver, em conjunto com a empresa, uma solução que melhor se adequasse aos seus requisitos do projeto. A estrutura foi submetida a estudos estáticos e modais nas diferentes condições a que está sujeita. Estes estudos foram realizados com o intuito de otimizar a estrutura de modo a obter uma redução da massa, implementar soluções práticas a nível técnico da instalação e benéficas para um melhor desempenho estrutural. A estrutura a desenvolver tem de validar os coeficientes de segurança impostos e oferecer uma solução economicamente apelativa. A estrutura desenvolvida mostrou ser uma solução vantajosa e funcional para a empresa e será aplicada nas próximas centrais frigoríficas desenvolvidas. O produto final validou os requisitos de projeto, incluindo o coeficiente de segurança estabelecido, permitiu obter uma redução significativa da massa da estrutura, e constitui uma proposta economicamente viável.
The refrigeration industry has a primary role in a variety of sectors, such as transportation, food and chemicals. The wide use of refrigeration systems leads to its evolution with the aim of introducing new technologies and improving them in terms of less environmental impact. Nowadays the refrigeration plants that utilize CO2 as a working fluid in the transcritical regime provide an excellent response to the currently applicable legislations. Companies like RACE (host company) faced the new challenges of the refrigeration sector and made the decision to develop its own product line. Initially, a structure was developed for a refrigeration plant operating with CO2, with the objective of offering the best product solutions to its customers. That said, the company felt the need to optimize the metal structure of its refrigeration plant. This dissertation consisted of the study of this structure, through structural studies implementing the Finite Element Method (FEM) to the initial model of the structure, in order to present an improvement plan to this plant and thus develop, together with the company, a solution that best suits its project requirements. The structure has undergone static and modal studies under the different conditions to which it is subjected to throughout the entire process. These studies were carried out in order to optimize the structure and achieve a reduction in its mass, implement practical solutions at the technical level of the installation and benefits for better structural performance. The structure to be developed must validate the imposed safety coefficients and offer an economically appealing solution. The developed structure proved to be an advantageous and functional solution for the company and will be applied in refrigeration plants developed in the future. The final product validated the design requirements, including the established safety coefficient, allowed a significant reduction in the mass of the structure, and is seen as an economically viable option.
The refrigeration industry has a primary role in a variety of sectors, such as transportation, food and chemicals. The wide use of refrigeration systems leads to its evolution with the aim of introducing new technologies and improving them in terms of less environmental impact. Nowadays the refrigeration plants that utilize CO2 as a working fluid in the transcritical regime provide an excellent response to the currently applicable legislations. Companies like RACE (host company) faced the new challenges of the refrigeration sector and made the decision to develop its own product line. Initially, a structure was developed for a refrigeration plant operating with CO2, with the objective of offering the best product solutions to its customers. That said, the company felt the need to optimize the metal structure of its refrigeration plant. This dissertation consisted of the study of this structure, through structural studies implementing the Finite Element Method (FEM) to the initial model of the structure, in order to present an improvement plan to this plant and thus develop, together with the company, a solution that best suits its project requirements. The structure has undergone static and modal studies under the different conditions to which it is subjected to throughout the entire process. These studies were carried out in order to optimize the structure and achieve a reduction in its mass, implement practical solutions at the technical level of the installation and benefits for better structural performance. The structure to be developed must validate the imposed safety coefficients and offer an economically appealing solution. The developed structure proved to be an advantageous and functional solution for the company and will be applied in refrigeration plants developed in the future. The final product validated the design requirements, including the established safety coefficient, allowed a significant reduction in the mass of the structure, and is seen as an economically viable option.
Description
Keywords
Estruturas metálicas Projeto mecânico Métodos de Elementos Finitos (MEF) Análise estática Análise modal Centrais frigoríficas Metallic structures Mechanical design Finite Element Method (FEM) Static analysis Modal analysis Refrigeration plants