Efficacy of greenhouse natural ventilation: Environmental monitoring and CFD simulations of a study case

Benni, Stefano; Tassinari, Patrizia; Bonora, Filippo; Barbaresi, Alberto; Torreggiani, Daniele

doi:10.1016/j.enbuild.2016.05.014

Cited by 121 publications

(58 citation statements)

References 26 publications

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“…Regarding the results obtained in the previous works, many studies have focused on the effect of the air flow variation on the temperature distribution inside the greenhouse . The distribution of air velocity inside the greenhouse was not thoroughly investigated . The effect of the direct and diffuse solar irradiation on the air temperature and velocity distribution inside the GHSD, which can be easily simulated using CFD discrete ordinate (DO) model, has not been taken into account in several previous studies.…”

Section: Introductionmentioning

confidence: 99%

“…14,15,[24][25][26] There are several studies conducted on the greenhouse solar in which programming software such as MATLAB, C/C ++, Fortran, and TRNSYS has been used to simulate the behavior of air flow inside GHDs, 16,[27][28][29][30][31][32][33] but very few studies have been done using the CFD software. Among the studies in which CFD was used, several of them were based on the twodimensional (2D) GHD geometric model, 14,17,18,24,[34][35][36] which cannot provide detailed information on the behavior of moist air in the entire GHD volume. Few studies have been carried out based on GHD's 3D geometric model.…”

Section: Introductionmentioning

confidence: 99%

“…17,34,38,39 The distribution of air velocity inside the greenhouse was not thoroughly investigated. 18,24,26,[35][36][37] The effect of the direct and diffuse solar irradiation on the air temperature and velocity distribution inside the GHSD, which can be easily simulated using CFD discrete ordinate (DO) model, 14 has not been taken into account in several previous studies. Another important aspect that is not wisely investigated is the air turbulent flow behavior in the GHD and its effect on the temperature distribution.…”

Section: Introductionmentioning

confidence: 99%

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Computational fluid dynamics analysis of heat transfer in a greenhouse solar dryer “chapel‐type” coupled to an air solar heating system

Román-Roldán

López‐Ortiz

Ituna-Yudonago

et al. 2019

Energy Science & Engineering

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The distribution of turbulent kinetic energy (TKE), temperature, and velocity of humid air inside the greenhouse solar dryer (GHSD) was numerically investigated using 3D CFD ANSYS FLUENT code. The effect of solar radiation was coupled with the energy equations using the discrete ordinate model. Numerical simulations were based on two geometric models: Real model and model with reduced height, the solution was in good agreement with experimental data of temperature. The results of the real model showed that the TKE is ranged between 1.27 m2/s2 and 6 m2/s2 with an average of about 1.6 m2/s2 for the entire greenhouse dryer (GHD) volume. The greatest TKE magnitude is in the paths of the diffusers, which caused a temperature drop of about 2 K in the areas near the walls. Consequently, almost homogeneous temperature distribution was obtained in the entire volume of the GHD, although the average temperature was 315 K, and a gradient with respect to ambient temperature was of 14 K, that is, suitable for drying. Also, the average air velocity at 1 m height was 0.71 m/s, which is a value near the lowest limit (0.6 m/s) of forced convection drying. The improvement in the GHD by 36.5% volume reduction allowed an increase in the average TKE of 3.8 m2/s2 (2.4 times more than the previous one) located in the middle of the greenhouse; the average temperature reached 316.5 K with a gradient of 15.5 K, which represents an increase of 1.5 K (11%) compared to the real geometric model. The air velocity at 1 m height increased to 0.9 m/s in the improved geometric model (a growth of 35.7% compared with the previous geometry). More than 95% of the improved GHD volume has a uniform temperature, which is very suitable for a good quality drying process with higher speed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Computational fluid dynamics analysis of heat transfer in a greenhouse solar dryer “chapel‐type” coupled to an air solar heating system

Román-Roldán

López‐Ortiz

Ituna-Yudonago

et al. 2019

Energy Science & Engineering

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“…This numerical simulation tool allows the development of 2D and 3D studies, where different study variables or environmental scenarios can be incorporated for evaluation, with the great methodological advantage of carrying out the different experiments without the need to build prototypes or real scenarios (Bouhoun Ali et al, 2017), obtaining results that have proven to be reliable (He et al, 2017). The use of CFD for the study of natural ventilation in different types of greenhouses has been extensive and significant as summarized in the work developed by (Bournet and Boulard, 2010) and currently the two-dimensional approaches continue to prove to be a simplification that generates precise results in research focused on the study of the configuration of ventilation in greenhouses and its effect on the microclimate (Benni et al, 2016).…”

Section: Introductionmentioning

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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“…Natural ventilation has a crucial role in the environmental sustainability of greenhouses (Bartzanas et al, 2004;He et al, 2015), it is deeply affected by the external conditions and it is dependent on vent sizes and dispositions (Katsoulas et al, 2006;Benni et al, 2016). The first experiments on air circulation in a greenhouse were performed in the mid-1950s, to evaluate the influence of the openings on the ventilation efficiency as it was reported in literature (Mistriotis et al, 1997b).…”

Section: Introductionmentioning

confidence: 99%

Calibration and comparison of different CFD approaches for airflow analysis in a glass greenhouse

Benni

Santolini

Barbaresi

et al. 2017

J Agricult Engineer

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CFD has been increasingly applied to greenhouses to optimise indoor environmental conditions for cultivation and management. Numerical simulations have proved fundamental for the enhancement of energy-efficient design criteria and management procedures. The objective of the study is the comparison between different computational approaches for the study of airflow patterns in a representative study case of a glass greenhouse, also through the calibration of the models and the validation of simulation results against experimental data. A three-span greenhouse of about 300 m 2 located in Emilia-Romagna (Italy) has been considered as study case. Several analyses with the same boundary and initial conditions were performed using two codes, broadly used for research and design purposes. With both programs, 2D or 3D models have been used and, for every case, the grid convergence was verified by performing multiple steady state analyses with increasingly finer meshes. The results led to define the most suitable solutions to set up computational models for the simulation of airflow patterns inside a greenhouse. The study provided a preliminary outline of the differences due to the adoption of various computational approaches characterised by different levels of accuracy and complexity. The results indicate the advisability of further developing the research by carrying out deeper experimental insights necessary to quantify more in detail the validity and the reliability of the adopted analytical methodologies.

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Efficacy of greenhouse natural ventilation: Environmental monitoring and CFD simulations of a study case

Cited by 121 publications

References 26 publications

Computational fluid dynamics analysis of heat transfer in a greenhouse solar dryer “chapel‐type” coupled to an air solar heating system

Computational fluid dynamics analysis of heat transfer in a greenhouse solar dryer “chapel‐type” coupled to an air solar heating system

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

Calibration and comparison of different CFD approaches for airflow analysis in a glass greenhouse

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