Medidas da radiação solar difusa em superfície vertical pelo método do anel de sombreamento MEO
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Data
2023-02-03
Autores
Piacitelli Tieghi, Camila
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Universidade Estadual Paulista (Unesp)
Resumo
A energia proveniente do Sol pode ser aproveitada para diversos fins, como conversão energética, térmica e conforto térmico. Seu uso térmico e para conforto já é difundido em diversas áreas, como Arquitetura, Engenharia civil, Agronomia e Zootecnia. O uso da energia solar como fonte geradora de eletricidade está ganhando espaço nos últimos anos, junto com a preocupação do uso de combustíveis fósseis como fonte de energia, pois além de serem limitados, são grandes causadores de emissões de CO2 na atmosfera. A radiação solar é uma das fontes renováveis e limpas de energia. A radiação solar difusa é uma fração da radiação solar global, que incide sobre à superfície terrestre após interagir com moléculas, poeira e água dispersos na atmosfera. A fotossíntese das plantas está intimamente relacionada à radiação solar difusa. Além disso, o conhecimento da radiação difusa é essencial para projetar e monitorar coletores solares passivos e ativos, Iluminação natural, na Agricultura, promovendo o crescimento de produção de culturas, Fotografia (iluminação) e na climatização de ambientes internos. Este trabalho teve como objetivo avaliar os dados da irradiação solar difusa em superfície vertical orientada ao Norte medidos durante os anos de 2019, 2020 e 2021, na estação de radiometria do Departamento de Engenharia de Biopocessos e Biotecnologia da Faculdade de Ciências Agronômicas da UNESP de Botucatu. No capítulo 1, foi proposto um fator de correção geométrico para o anel de sombreamento da radiação solar difusa medida em superfície vertical ao Norte. No capítulo 2, foi criada uma evolução das medidas da radiação solar difusa em superfície vertical, medida através de um anel de sombreamento do tipo MEO inclinado na vertical ao Norte, comparadas com medidas realizadas pelo mesmo método em superfície horizontal, a fim de se adquirir níveis quantitativos de irradiação solar difusa em superfície vertical ao Norte no decorrer dos anos para Botucatu–SP. Para as medidas da radiação difusa em superfície horizontal, foram obtidos os valores médios de 5 MJ/m² em 2019, 4,3 MJ/m² em 2020, 6 MJ/m² em 2021. Para a radiação difusa em superfície vertical, em 2019, os valores médios e medianos foram iguais, de 4,2 MJ/m². Em 2020, as médias e medianas aumentaram para 5 MJ/m². Em 2021, o valor médio anual foi de 4,61 MJ/m². No capítulo 3, foram testados seis modelos clássicos de estimativa da fração difusa da radiação solar em superfícies inclinadas comparados com medidas da radiação difusa em superfície vertical ao Norte. Devido ao alto ângulo de inclinação (90°), os resultados obtidos na aplicação dos modelos clássicos para estimativa da porção solar difusa não mostraram boa precisão comparando com dados medidos. Os dados medidos podem ser utilizados para fins de aproveitamento energético, térmico ou iluminação passiva.
The energy from the Sun can be used for various purposes, such as energy conversion, thermal and thermal comfort. Its thermal and comfort use is already widespread in several areas, such as Architecture, Civil Engineering, Agronomy and Animal Science. The use of solar energy as a source of electricity has been gaining ground in recent years, along with the concern for the use of fossil fuels as a source of energy, as in addition to being limited, they are major causes of CO2 emissions into the atmosphere. Solar radiation is one of the renewable and clean sources of energy. Diffuse solar radiation is a fraction of global solar radiation, which falls on the Earth's surface after interacting with molecules, dust and water dispersed in the atmosphere. Plant photosynthesis is closely related to diffuse solar radiation. In addition, knowledge of diffuse radiation is essential for designing and monitoring passive and active solar collectors, Natural lighting, in Agriculture, promoting the growth of crop production, Photography (lighting) and indoor air conditioning. This work aimed to evaluate the data of diffuse solar irradiation on a vertical surface oriented to the North measured during the years 2019, 2020 and 2021, at the radiometry station of the Department of Bioprocess Engineering and Biotechnology of the Faculty of Agricultural Sciences of UNESP in Botucatu . In Chapter 1, a geometric correction factor was proposed for the shading ring of diffuse solar radiation measured on a vertical surface to the North. In chapter 2, an evolution of the measurements of diffuse solar radiation on a vertical surface was created, measured through a shading ring of the MEO type tilted vertically to the North, compared with measurements carried out by the same method on a horizontal surface, in order to acquire quantitative levels of diffuse solar irradiation on a vertical surface to the North over the years for Botucatu-SP. For measurements of diffuse radiation on a horizontal surface, average values of 5 MJ/m² were obtained in 2019, 4.3 MJ/m² in 2020, 6 MJ/m² in 2021. For diffuse radiation on a vertical surface, in 2019, mean and median values were equal, 4.2 MJ/m². In 2020, the averages and medians increased to 5 MJ/m². In 2021, the average annual value was 4.61 MJ/m². In Chapter 3, six classic models for estimating the diffuse fraction of solar radiation on inclined surfaces were tested, compared with measurements of diffuse radiation on a vertical surface to the North. Due to the high angle of inclination (90°), the results obtained in the application of classical models for estimating the diffuse solar portion did not show good accuracy when compared with measured data. The measured data can be used for energy, thermal or passive lighting purposes.
The energy from the Sun can be used for various purposes, such as energy conversion, thermal and thermal comfort. Its thermal and comfort use is already widespread in several areas, such as Architecture, Civil Engineering, Agronomy and Animal Science. The use of solar energy as a source of electricity has been gaining ground in recent years, along with the concern for the use of fossil fuels as a source of energy, as in addition to being limited, they are major causes of CO2 emissions into the atmosphere. Solar radiation is one of the renewable and clean sources of energy. Diffuse solar radiation is a fraction of global solar radiation, which falls on the Earth's surface after interacting with molecules, dust and water dispersed in the atmosphere. Plant photosynthesis is closely related to diffuse solar radiation. In addition, knowledge of diffuse radiation is essential for designing and monitoring passive and active solar collectors, Natural lighting, in Agriculture, promoting the growth of crop production, Photography (lighting) and indoor air conditioning. This work aimed to evaluate the data of diffuse solar irradiation on a vertical surface oriented to the North measured during the years 2019, 2020 and 2021, at the radiometry station of the Department of Bioprocess Engineering and Biotechnology of the Faculty of Agricultural Sciences of UNESP in Botucatu . In Chapter 1, a geometric correction factor was proposed for the shading ring of diffuse solar radiation measured on a vertical surface to the North. In chapter 2, an evolution of the measurements of diffuse solar radiation on a vertical surface was created, measured through a shading ring of the MEO type tilted vertically to the North, compared with measurements carried out by the same method on a horizontal surface, in order to acquire quantitative levels of diffuse solar irradiation on a vertical surface to the North over the years for Botucatu-SP. For measurements of diffuse radiation on a horizontal surface, average values of 5 MJ/m² were obtained in 2019, 4.3 MJ/m² in 2020, 6 MJ/m² in 2021. For diffuse radiation on a vertical surface, in 2019, mean and median values were equal, 4.2 MJ/m². In 2020, the averages and medians increased to 5 MJ/m². In 2021, the average annual value was 4.61 MJ/m². In Chapter 3, six classic models for estimating the diffuse fraction of solar radiation on inclined surfaces were tested, compared with measurements of diffuse radiation on a vertical surface to the North. Due to the high angle of inclination (90°), the results obtained in the application of classical models for estimating the diffuse solar portion did not show good accuracy when compared with measured data. The measured data can be used for energy, thermal or passive lighting purposes.
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Palavras-chave
energia solar, difusa, fonte renovável de energia, modelos de estimativa, vertical, solar energy, diffuse, renewable source of energy, estimation models