Alternative methods to identify the solar absorptance of opaque surfaces

Alternative methods to identify the solar absorptance of opaque surfaces

In this paper, two alternative methods to identify the solar absorptance of opaque surfaces are presented. In the first method, samples painted with different paint colours were classified according to the RGB and HSL digital chromatic systems. In the second method, the reflectances of the samples w...

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Main Authors: Dornelles, Kelen Almeida, Roriz, Maurício
Format: Online
Language:por
Published: ANTAC - Associação Nacional de Tecnologia do Ambiente Construído 2008
Online Access:https://seer.ufrgs.br/ambienteconstruido/article/view/3745
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spelling ojs-article-37452008-04-28T17:10:49Z Alternative methods to identify the solar absorptance of opaque surfaces Métodos alternativos para identificar a absortância solar de superfícies opacas Dornelles, Kelen Almeida Roriz, Maurício Absortância solar; Refletância solar; Cores; Superfícies opacas; Espectro solar padrão In this paper, two alternative methods to identify the solar absorptance of opaque surfaces are presented. In the first method, samples painted with different paint colours were classified according to the RGB and HSL digital chromatic systems. In the second method, the reflectances of the samples were measured with a low cost spectrometer for radiations in eleven different wavelengths, from 470 nm to 940 nm. Based on reflectance data obtained in laboratory, equations were developed to estimate reflectances for the visible and the total range of the solar spectrum, according to the spectrometer and the RGB and HSL data. The reflectances obtained in laboratory were adjusted to the standard solar spectrum in order to indicate the amount of relative energy that is reflected for the surfaces when exposed to solar radiation. The results show that the alternative methods presented in this paper are reliable and accessible for specialists and designers, which will be useful for obtaining reflectance and absorptance data more realistic than those presented in existing published tables. Neste artigo, são apresentados dois métodos alternativos para identificar a absortância solar de superfícies opacas. No primeiro método, amostras de superfícies pintadas com diferentes cores e tipos de tintas foram digitalizadas em scanner, e cada amostra foi classificada segundo os sistemas cromáticos digitais RGB e HSL. No segundo método, as refletâncias das amostras foram medidas com um espectrômetro de baixo custo, para radiações em onze diferentes comprimentos de onda, entre 470 nm e 940 nm. Com base em dados de refletância obtidos em laboratório, foram desenvolvidas equações que permitem estimar, a partir dos dados dos sistemas cromáticos digitais e do espectrômetro, as refletâncias para a região visível e para o espectro solar total. As refletâncias obtidas em espectrofotômetro também foram ajustadas ao espectro solar padrão, para indicar a quantidade de energia relativa que é refletida pelas superfícies, quando expostas à radiação solar. Os resultados obtidos indicam que os métodos alternativos apresentados neste trabalho são confiáveis e acessíveis a especialistas e projetistas, contribuindo para a obtenção de valores de refletâncias e absortâncias mais realistas do que os apresentados em tabelas publicadas até o momento. ANTAC - Associação Nacional de Tecnologia do Ambiente Construído 2008-04-28 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf https://seer.ufrgs.br/ambienteconstruido/article/view/3745 Ambiente Construído; v. 7, n. 3 (2007); 109-127 Ambiente Construído; v. 7, n. 3 (2007); 109-127 Ambiente Construído; v. 7, n. 3 (2007); 109-127 1678-8621 1415-8876 por https://seer.ufrgs.br/ambienteconstruido/article/view/3745/2098 Direitos autorais 2016 Ambiente Construído https://creativecommons.org/licenses/by/4.0
institution Universidade Federal do Rio Grande do Sul
collection OJS
language por
format Online
author Dornelles, Kelen Almeida
Roriz, Maurício
spellingShingle Dornelles, Kelen Almeida
Roriz, Maurício
Alternative methods to identify the solar absorptance of opaque surfaces
author_facet Dornelles, Kelen Almeida
Roriz, Maurício
author_sort Dornelles, Kelen Almeida
title Alternative methods to identify the solar absorptance of opaque surfaces
title_short Alternative methods to identify the solar absorptance of opaque surfaces
title_full Alternative methods to identify the solar absorptance of opaque surfaces
title_fullStr Alternative methods to identify the solar absorptance of opaque surfaces
title_full_unstemmed Alternative methods to identify the solar absorptance of opaque surfaces
title_sort alternative methods to identify the solar absorptance of opaque surfaces
description In this paper, two alternative methods to identify the solar absorptance of opaque surfaces are presented. In the first method, samples painted with different paint colours were classified according to the RGB and HSL digital chromatic systems. In the second method, the reflectances of the samples were measured with a low cost spectrometer for radiations in eleven different wavelengths, from 470 nm to 940 nm. Based on reflectance data obtained in laboratory, equations were developed to estimate reflectances for the visible and the total range of the solar spectrum, according to the spectrometer and the RGB and HSL data. The reflectances obtained in laboratory were adjusted to the standard solar spectrum in order to indicate the amount of relative energy that is reflected for the surfaces when exposed to solar radiation. The results show that the alternative methods presented in this paper are reliable and accessible for specialists and designers, which will be useful for obtaining reflectance and absorptance data more realistic than those presented in existing published tables.
publisher ANTAC - Associação Nacional de Tecnologia do Ambiente Construído
publishDate 2008
url https://seer.ufrgs.br/ambienteconstruido/article/view/3745
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AT rorizmauricio alternativemethodstoidentifythesolarabsorptanceofopaquesurfaces
AT dornelleskelenalmeida metodosalternativosparaidentificaraabsortanciasolardesuperficiesopacas
AT rorizmauricio metodosalternativosparaidentificaraabsortanciasolardesuperficiesopacas
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