Yearly numerical evaluation of greenhouse cover materials

Baxevanou, Catherine; Fidaros, D.; Bartzanas, Thomas; Kittas, C.

doi:10.1016/j.compag.2017.12.006

Cited by 43 publications

(32 citation statements)

References 30 publications

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“…The selection of greenhouse materials is also formed by seasons; this is because seasons determine the variations in energy and heat quirements in summer (in the south) and winter (in the north) [16]. In particular, materials with a gh transmittance coefficient are suitable for constructing greenhouse materials during winter cause they do not filter out photosynthetically active radiation (PAR) [17]. In contrast, materials ssessing high PAR coefficients are unsuitable during summer due to the risk of overheating and e need for alternative cooling such as evaporation cooling.…”

Section: Type Of Materials τPar ρPar αPar τNir ρNir αNir Qmentioning

confidence: 99%

“…However, universal adoption has been curtailed by cost, as illustrated in Table 2 [37]. The bio-plastics are slightly expensive compared to petroleum-based plastics; it costs between €0.77-0.81 to manufacture petroleum-based plastics such as PVC, PP, PET, thermal polyethylene film (TPE), ethylene-vinyl acetate film (EVA), and three-layer co-extruded film (3L) [17]. In contrast, it costs up to €12.00/kg to manufacture polyhydroxyalkanoates (PHA).…”

Section: Glass Plastic Sheets and Filmsmentioning

confidence: 99%

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Environmental Sustainability of Greenhouse Covering Materials

Maraveas

2019

Sustainability

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The fundamental objective of the review article was to explore the ecological sustainability of greenhouse covering material based on the following themes; considerations for greenhouse materials, properties of polymers and glass, additives, fillers, stabilizers and reinforcements, performance, Ultraviolet (UV) transmittance, phase change materials (PCMs), and environmental sustainability. A comparison of various polymers (polyvinyl chloride (PVC), acrylic, D-polymer, Linear low-density polyethylene (LLDPE), polyolefins), and silica glasses illustrated that each type of greenhouse cladding material has its unique merits and limitations. The performance of silica glasses, PVC, polyolefins was influenced by weather, greenhouse design, plant under cultivation, percentage UV transmittance, incorporation of additives and stabilizers, reinforcements, and integration of photovoltaic panels into the greenhouse roof among other factors. Polymers can be customized to achieve 0%UV transmittance, slow-insecticide release, and anti-microbial properties. In contrast, glass materials are preferred based on suitable photosynthetically active radiation (PAR) transmittance and near-infrared (NIR) reflection and less risk of photo-oxidation. From an ecological perspective, polymers can be recycled via mechanical and chemical recycling, closed-loop cycling, and polymerization of bio-based feedstock. However, post-consumer plastic films do not possess the same optical and energy properties as virgin polymers. The combined benefits of different polymers suggest that these materials could be adopted on a large scale over the long-term.

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Section: Type Of Materials τPar ρPar αPar τNir ρNir αNir Qmentioning

confidence: 99%

Section: Glass Plastic Sheets and Filmsmentioning

confidence: 99%

Environmental Sustainability of Greenhouse Covering Materials

Maraveas

2019

Sustainability

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“…El método de solución semi implícito para la ecuación de presión (SIMPLE) y el algoritmo de resolución de partición de presión implícita con la división de operadores (PISO) fue aplicado para resolver el campo de flujo del fluido simulado. Los criterios de convergencia del modelo fueron establecidos en 10 -8 para la ecuación de energía y en 10 -6 para las ecuaciones de continuidad, momento y turbulencia (Baxevanou et al, 2017).…”

Section: Dominio Computacional Y Generación De La Mallaunclassified

Simulacion Del Microclima en Un Invernadero Usado Para La Producción De Rosas Bajo Condiciones De Clima Intertropical

Villagrán

Bojacá

2019

Chil. j. agric. anim. sci.

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RESUMENEn Colombia, la producción de rosa (Rosa sp.) se desarrolla en un alto porcentaje en invernaderos ventilados en forma natural. El objetivo de este trabajo consistió en desarrollar una caracterización del microclima generado en el interior de un invernadero a través de la modelación numérica de los flujos de aire mediante un software CFD (Computational Fluids Dynamics) de volúmenes finitos. El modelo CFD-3D utilizado fue validado mediante recopilación de datos experimentales, y se compararon datos experimentales y simulados, los que mostraron un grado de ajuste adecuado y una misma tendencia para las variables de temperatura y humedad relativa. Los resultados obtenidos muestran que para condiciones de clima diurno el microclima generado se encuentra en rangos óptimos para la producción de rosa. Para condiciones de clima nocturno, se observó una presencia constante del fenómeno de inversión térmica del aire interior del invernadero, lo cual genera condiciones subóptimas para el crecimiento y desarrollo de las plantas.Palabras clave: invernadero, simulación CFD, temperatura, humedad relativa, periodo diurno, periodo nocturno. ABSTRACTIn Colombia, roses (Rosa sp.) are mostly cultivated in naturally ventilated greenhouses. The objective of this work was to develop a characterization of the microclimate generated inside a greenhouse through the numerical modelling of air flows by using the CFD (Computational Fluids Dynamics) software of finite volumes. The CFD-3D model used was validated through experimental data collection and the results obtained from the comparison of experimental and simulated data, which showed a suitable degree of adjustment and the same tendency for the variables of temperature and relative humidity. The results obtained show that, for daytime conditions, the microclimate generated is in optimal ranges for the production of rose. For night-time climate conditions, presence of thermal inversion phenomenon in the indoor air of the greenhouse was observed, which generates suboptimal conditions for the growth and development of plants.

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“…A semi-implicit method for pressure equations was adopted to solve the pressuremoment coupled equations using the SIMPLE algorithm. The convergence criterion was 10 -6 for the equations of energy, continuity, momentum and turbulence (Baxevanou et al, 2017).…”

Section: Computational Domain and Boundary Conditionsmentioning

confidence: 99%

Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic

Villagrán

Bojacá

2019

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In tropical regions the production of ornamentals is developed exclusively in naturally ventilated plastic greenhouses, which sometimes leads to inappropriate microclimates with high temperatures and humidity that limit the productive development of plants. The aim of this work was to study air flows, temperature distribution and relative humidity inside an alternative greenhouse designed to produce rose (Rosa spp.). Three configurations of ventilation, side ventilation (SV), roof ventilation (RC) and combined roof and side ventilation (RSV) were analyzed. The methodological development was based on the use of a previously validated CFD-2D numerical simulation model, which showed an adequate fit between the measured and simulated data, obtaining MAE and RMSE values for temperature and relative humidity of 0.44 and 0.47 °C, 3.99% and 4.04% respectively. The results obtained for the predominant climatic conditions of the study region showed that the highest ventilation rates were obtained for RSV, with values of 0.044 and 0.182 m 3 m -2 s -1 , this ventilation efficiency propitiated the generation of a homogeneous microclimate, with temperature and relative humidity values adequate to produce rose (Rosa spp). ResumoEstudo da ventilação natural em uma estufa gótica multi-túnel projetada para produzir rosa (Rosa spp.) no trópico alto-andino. Nas regiões tropicais, a produção de plantas ornamentais é desenvolvida exclusivamente em estufas plásticas ventiladas de forma natural, o que significa que em algumas ocasiões microclimas inadequados são gerados com altas temperaturas e umidade que limitam o desenvolvimento produtivo das plantas. O objetivo deste trabalho foi estudar os fluxos de ar, a distribuição de temperatura e umidade relativa do ar dentro de uma estufa alternativa projetada para a produção de rosa (Rosa spp.). Três configurações de ventilação, ventilação lateral (SV), ventilação de telhado (RC) e telhado combinado e ventilação lateral (RSV) foram analisadas. O desenvolvimento metodológico baseou-se na utilização de um modelo de simulação numérica CFD-2D previamente validado, que mostrou um ajuste adequado entre os dados medidos e simulados, obtenção de valores de MAE e RMSE para temperatura e umidade relativa de 0,44 e 0,47 ° C, 3,99 e 4,04% respectivamente. Os resultados obtidos para as condições climáticas predominantes da região de estudo mostraram que as maiores taxas de ventilação foram obtidas para o RSV, com valores de 0,044 e 0,182 m 3 m -2 s -1 , essa eficiência de ventilação propiciou a geração de um microclima homogêneo, com valores de temperatura e umidade relativa adequados para a produção de rosa (Rosa spp.). Palavras-chave: Microclima, taxa de ventilação, simulação de CFD, temperatura, umidade relativa, volumes finitos.

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Yearly numerical evaluation of greenhouse cover materials

Cited by 43 publications

References 30 publications

Environmental Sustainability of Greenhouse Covering Materials

Environmental Sustainability of Greenhouse Covering Materials

Simulacion Del Microclima en Un Invernadero Usado Para La Producción De Rosas Bajo Condiciones De Clima Intertropical

Study of natural ventilation in a Gothic multi-tunnel greenhouse designed to produce rose (Rosa spp.) in the high-Andean tropic

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