Effects of cover diffusive properties on the components of greenhouse solar radiation

Cabrera, Fernanda; Baille, Alain; López, J.C.; González-Real, M.M.; Pérez-Parra, J.J.

doi:10.1016/j.biosystemseng.2009.03.008

Cited by 42 publications

(30 citation statements)

References 40 publications

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“…The indicated values of the ratio (D i /G i ) for non-coloured screens, especially in the lower porosity types (up to ≈ 90%) (Fig. 3), were higher than those of light-diffusing polyethylene covering films reported by Cabrera et al (2009). Möller et al (2010) found that diffuse radiation below a non-black screen was much larger than that above the screens because of the contribution of scattered direct radiation in comparison to the diffuse radiation below the screens.…”

Section: Diffuse Component Of Solar Radiation Transmitted By Screens mentioning

confidence: 73%

“…Knowledge of the coefficient of diffuse radiation enrichment (D i /D o ) is of prime importance in crop models studies (Spitters, 1986), especially in those aimed at assessing the advantages and efficiency of a determined greenhouse cladding material. As mentioned by Cabrera et al (2009), the principle challenge in the future will be that of maximizing the beneficial effects of diffuse radiation upon the homogeneity of interception of radiation by the plant canopy and upon factors affecting crop yield.…”

Section: Introductionmentioning

confidence: 99%

“…For this reason, as stated by Cabrera et al (2009), since the pioneering work of Deltour & Nisen (1970), laboratory studies aimed at characterizing the diffusive properties of greenhouse cladding materials have become of paramount interest (Pearson et al, 1995;Wang & Deltour, 1999;Montero et al, 2001;Pollet et al, 2005). Diffuse radiation represents a significant fraction of the total solar radiation that enters a greenhouse (Baille & Tchamitchian, 1993), although few detailed studies have been undertaken to colours, thread diameters and porosities to: i) document the global and PAR transmittance values, ii) evaluate the screen transmission for diffuse solar radiation as well as the alterations of the radiation diffuse component when passing through the screens.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of global, photosynthetically active radiation and diffuse radiation transmission of agricultural screens

Romero-Gámez

Suárez-Rey

Castilla

et al. 2012

Span. j. agric. res.

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Transmittance of a material depends on the type of radiation impinging on the material (direct or diffuse), the angle of incidence of the sun's rays (in direct radiation conditions) and the structure and characteristics of the material itself. The aim of this study was to evaluate the performance of nine agricultural screens of different densities, colours, thread diameters and porosities. A simple metal frame was used to quantify global, diffuse and photosynthetically active radiation (PAR) transmission to determine their transmittance values (as a function of the incidence angle of solar rays in direct radiation conditions) for global radiation and PAR, as well as the diffuse radiation transmitted characteristics of the screens (ratio of diffuse radiation to global radiation transmitted by screens). Non-coloured (translucent) screens contributed to a higher and more efficient proportion of diffuse radiation (D i /G i ≈ 90%). The green screen behaved similarly to the non-coloured 20 × 10 type as far as global radiation was concerned, although the PAR transmittance values were lower (up to 12.4% at 15°). Variation in transmission according to diameter and density of the threads was greatest in the black screens. The non-coloured-thread screens may be the best option for maximising the transmission of diffuse radiation and the 6 × 6 green screen for vegetables cultivation during the summer in inland areas with latitudes close to 36° N.Additional key words: covering materials; incidence angle; porosity; screenhouse; transmittance. Resumen Evaluación de la transmisividad a radiación global, fotosintéticamente activa y difusa en mallas de uso agrícolaLa transmisividad de un material depende del tipo de radiación (directa o difusa) incidente en el material, del ángulo de incidencia de los rayos solares (en condiciones de radiación directa) y de la estructura y características del material. El objetivo de este estudio fue evaluar el comportamiento de nueve mallas de uso agrícola de diferente densidad, color, diámetro del hilo y porosidad. Para ello, se determinaron los valores de transmisividad a radiación solar global y PAR y la radiación solar difusa transmitida bajo malla para ángulos de incidencia diferentes, empleando un bastidor diseñado para tal efecto. Las mallas no coloreadas (translúcidas) consiguieron un enriquecimiento de la radiación difusa bajo ellas (D i /G i ≈ 90%). La malla verde tuvo un comportamiento transmisivo similar al de la malla no coloreada 20 × 10 para la radiación global mientras que en el caso de la radiación PAR sus valores de transmisividad fueron menores (hasta 12,4% para 15°). La variación de transmisividad con el grosor y la densidad de los hilos fue mayor en las mallas negras. Las mallas no coloreadas podrían ser la mejor opción para maximizar la transmisividad a radiación difusa y la malla verde 6 × 6 para el cultivo de hortícolas durante la época estival en zonas de interior de latitudes cercanas a 36° N.

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Section: Diffuse Component Of Solar Radiation Transmitted By Screens mentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of global, photosynthetically active radiation and diffuse radiation transmission of agricultural screens

Romero-Gámez

Suárez-Rey

Castilla

et al. 2012

Span. j. agric. res.

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“…The solar position and outside weather conditions also contribute to the τ gh . A variety of studies on the τ gh have considered the incidence angle of solar radiation (Bowman, 1970), weather conditions (Leonidopoulos, 2000;Cabrera et al, 2009), greenhouse orientation (Papadakis et al, 1998;Li et al, 2000), structural members (Critten, 1987), and dust and dirt on the covering (Geoola et al, 1998). Because the results on τ gh vary from 25% to 59%, according to experimental conditions, applying a specific τ gh for the energy input equation was difficult.…”

Section: Al 2009mentioning

confidence: 99%

Surplus thermal energy model of greenhouses and coefficient analysis for effective utilization

Yang

Son

Lee

et al. 2016

Span. j. agric. res.

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This study concentrates on the utilization of surplus thermal energy (STE) in greenhouses. Even in the cold season, the thermal energy input from solar radiation easily exceeds the required amount for heating on a clear day in the temperate or subtropical regions. This excessive solar energy is regarded as STE. There are several studies related to the STE energy (Pavlou, 1991; Suh et RESEARCH ARTICLE OPEN ACCESS AbstractIf a greenhouse in the temperate and subtropical regions is maintained in a closed condition, the indoor temperature commonly exceeds that required for optimal plant growth, even in the cold season. This study considered this excess energy as surplus thermal energy (STE), which can be recovered, stored and used when heating is necessary. To use the STE economically and effectively, the amount of STE must be estimated before designing a utilization system. Therefore, this study proposed an STE model using energy balance equations for the three steps of the STE generation process. The coefficients in the model were determined by the results of previous research and experiments using the test greenhouse. The proposed STE model produced monthly errors of 17.9%, 10.4% and 7.4% for December, January and February, respectively. Furthermore, the effects of the coefficients on the model accuracy were revealed by the estimation error assessment and linear regression analysis through fixing dynamic coefficients. A sensitivity analysis of the model coefficients indicated that the coefficients have to be determined carefully. This study also provides effective ways to increase the amount of STE.Additional key words: energy balance; energy conservation; environmental control; heat pump; heat storage Abbreviations used: FCU (fan coil unit); HST (high temperature heat storage tank); LST (low temperature heat storage tank); mPLAI (modified PLAI, ratio of total projected leaf area to the floor area); PLAI (projected leaf area index, projected area of horizontal leaves per unit of horizontal land below); SHEF (sensible heat emission factor); STE (surplus thermal energy) Citation: Yang, S. H.; Son, J. E.; Lee, S. D.; Cho, S. I.; Ashtiani-Araghi, A.; Rhee, J. Y. (2016). Surplus thermal energy model of greenhouses and coefficient analysis for effective utilization.

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“…Portanto, o telhado e as laterais da casa de vegetação e/ou telados devem estar sempre limpos, sem poeira impregnada, a qual reduz substancialmente a luminosidade no interior da casa, causando problemas sérios no crescimento e no desenvolvimento vegetal, reduzindo a fotossíntese e promovendo estiolamento das plantas (BELTRÃO et al, 2002). O fluxo de radiação transmitido em uma casa de vegetação também é afetado por fatores extrínsecos, além da poeira, tais como: condensação da umidade atmosférica, envelhecimento do material plástico e o design da estufa (estruturas de sustentação) (CABRERA et al, 2009).…”

Section: Influência Da Cobertura Plástica Na Incidência De Radiação Sunclassified

Radiação solar e temperatura do ar em ambiente protegido.

Rebouças

Dias

Alves

et al. 2014

AGGA

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ResumoO cultivo realizado em casa de vegetação é uma das tecnologias que têm contribuído para a modernização da agricultura, atenuando os danos causados pelas adversidades climáticas e, consequentemente, vem colaborando com o aumento da produção de alimentos no Brasil e no mundo. Diante disso, esta revisão tem o objetivo de descrever o comportamento das variáveis ambientais, radiação solar e temperatura do ar em um ambiente protegido com cobertura plástica, com enfoque nos aspectos climáticos envolvidos, sob as culturas agrícolas. Palavras-chave: Cultivo protegido. Agricultura. Variáveis climáticas. IntroduçãoO uso do plástico na cobertura de casas de vegetação surgiu como alternativa na proteção de hortaliças e flores, diante das adversidades climáticas. Vida et al. (2004) sintetizaram algumas vantagens do cultivo em estufas ou ambientes protegidos, como: o aumento de produtividade, colheita na entressafra, precocidade da colheita, maior qualidade dos produtos, melhor controle das condições ambientais, controle mais eficiente de pragas e doenças, melhor aproveitamento no uso dos recursos, minimização do risco e maximização da competitividade mercadológica do produtor. De acordo com Beltrão et al. (2002), o cultivo em estufa possibilita determinado controle das condições edafoclimáticas, tais como: temperatura, umidade do ar, radiação luminosa, solo, vento e composição atmosférica, e implica a utilização de instrumentação e dispositivos de controle apropriados .No mundo, parte significativa da pesquisa agrícola e da produção de algumas plantas ornamentais e hortaliças é realizada em casas de vegetação ou teladas (casas de plástico não climatizadas), na maioria dos casos, sem controle do ambiente (luz, irradiação solar global, irradiação infravermelha e calórica, umidade relativa e temperatura do ar).Estima-se que, nas últimas décadas, o cultivo em ambiente protegido no Brasil apresentou crescimento significativo, principalmente para a produção de hortaliças e flores que possuem elevado REBOUÇAS, P. M.; DIAS, I. F.; ALVES, M. A.; BARBOSA FILHO, J. A. D. Radiação solar e temperatura do ar em ambiente protegido. Revista Agrogeoambiental, Pouso Alegre, v. 7, n. 2, p. 115-125, jun. 2015.

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Effects of cover diffusive properties on the components of greenhouse solar radiation

Cited by 42 publications

References 40 publications

Evaluation of global, photosynthetically active radiation and diffuse radiation transmission of agricultural screens

Evaluation of global, photosynthetically active radiation and diffuse radiation transmission of agricultural screens

Surplus thermal energy model of greenhouses and coefficient analysis for effective utilization

Radiação solar e temperatura do ar em ambiente protegido.

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