Avaliação experimental da eficiência térmica de coletor solar plano com barreiras internas
Carregando...
Data
2019-03-01
Autores
Garcia, Rafael Paiva
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A mudança na geração de energia através de fontes não renováveis para fontes renováveis é uma grande preocupação mundial e nacional, que tem impulsionado pesquisas e desenvolvimentos de tecnologias na área de energia renovável. Neste cenário, a energia solar é uma excelente alternativa, por ter um grande potencial e diversas aplicações. Com isso, este trabalho tem o objetivo de analisar melhorias na eficiência de coletor solar plano, equipamento utilizado no aquecimento de água através da energia solar, ao adicionar barreiras na cavidade de ar confinado entre a sua placa absorvedora e a sua cobertura de vidro. As barreiras bloqueiam o fluxo de ar, provocado pela convecção interna, diminuindo as perdas de calor. A análise foi realizada em quatro coletores, nos quais foram adicionados de uma a quatro barreiras e comparados com um coletor sem barreira como referência. Para isso, foi construída uma bancada de teste com todos equipamentos necessários para obter a eficiência em coletor solar plano. Os resultados dos ensaios mostraram que não houve uma variação significativa da absorção de radiação solar, já que a eficiência máxima manteve-se inalterada. Porém, houve uma diminuição da perda de calor ao adicionar as barreiras, sendo esse resultado diretamente relacionado a inclinação da curva de eficiência usada na análise de coletor solar plano. Os resultados mostram que a inclinação varia em -2,05%, -5,12% e 2,94%, para duas a quatro barreiras, respectivamente. Portanto, as barreiras diminuem a perda de calor para o meio, havendo um número ótimo de barreiras para cada projeto de coletor solar plano.
The shift in power generation from non-renewable sources to renewable sources is a major global and national concern that has driven research and development of renewable energy technologies. In this scenario, the solar energy is an excellent alternative, for having great potential and diverse applications. With this, the objective of this work is to analyze improvements in the efficiency of solar collector flat, equipment used in heating water through solar energy, by adding barriers in the confined air cavity between its absorber plate and its glass cover. The barriers block the flow of air, caused by internal convection, reducing heat losses. The analysis was performed on four collectors, in which one to four barriers were added and compared with a barrierless collector as a reference. For this, a test bench was built with all the necessary equipment to obtain the efficiency in the flat solar collector. The results of the tests showed that there was no significant variation in the absorption of solar radiation since the maximum efficiency remained unchanged. However, there was a decrease of the heat loss when adding the barriers, being this result directly related to the slope of the curve of efficiency used in the analysis of flat solar collector. The results show that the slope varies by -2.05%, -5.12% and 2.94% for two to four barriers, respectively. Therefore, the barriers reduce the heat loss to the medium, with an optimal number of barriers for each flat solar collector project.
The shift in power generation from non-renewable sources to renewable sources is a major global and national concern that has driven research and development of renewable energy technologies. In this scenario, the solar energy is an excellent alternative, for having great potential and diverse applications. With this, the objective of this work is to analyze improvements in the efficiency of solar collector flat, equipment used in heating water through solar energy, by adding barriers in the confined air cavity between its absorber plate and its glass cover. The barriers block the flow of air, caused by internal convection, reducing heat losses. The analysis was performed on four collectors, in which one to four barriers were added and compared with a barrierless collector as a reference. For this, a test bench was built with all the necessary equipment to obtain the efficiency in the flat solar collector. The results of the tests showed that there was no significant variation in the absorption of solar radiation since the maximum efficiency remained unchanged. However, there was a decrease of the heat loss when adding the barriers, being this result directly related to the slope of the curve of efficiency used in the analysis of flat solar collector. The results show that the slope varies by -2.05%, -5.12% and 2.94% for two to four barriers, respectively. Therefore, the barriers reduce the heat loss to the medium, with an optimal number of barriers for each flat solar collector project.
Descrição
Palavras-chave
Coletor solar plano, Convecção natural, Eficiência térmica, Flat solar collector, Natural convection, Thermal efficiency