Determinación de las tasas de ventilación natural en un invernadero mediante modelos teóricos y gases trazadores

Trujano, Daniel Espejel; Cruz, Irineo Lorenzo López

doi:10.29312/remexca.v4i2.1231

Cited by 4 publications

(4 citation statements)

References 17 publications

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“…These results reaffirm some conclusions already determined in previous works related to the natural ventilation of greenhouses, where it was identified that the renewal indexes are dependent on the ventilation configuration used [68][69][70][71]. It was also identified that there is a linear relationship between the renewal index and wind speed [38,56,72,73], the ventilation configuration that allows to obtain the highest renewal index values is the combined configuration of roof and side vents [10,16,74,75].…”

Section: Renewal Index (Ri)supporting

confidence: 89%

Influence of the Height in a Colombian Multi-Tunnel Greenhouse on Natural Ventilation and Thermal Behavior: Modeling Approach

Villagrán

Flores²,

Akrami

et al. 2021

Sustainability

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The dimensions of a passive greenhouse are one of the decisions made by producers or builders based on characteristics of the available land and the economic cost of building the structure per unit of covered area. In few cases, the design criteria are reviewed and the dimensions are established based on the type of crop and local climate conditions. One of the dimensions that is generally exposed to greater manipulation is the height above the gutter and the general height of the structure, since a greenhouse with a lower height has a lower economic cost. This has led some countries in the tropical region to build greenhouses that, due to their architectural characteristics, have inadequate microclimatic conditions for agricultural production. The objective of this study was to analyze the effect on air flows and thermal distribution generated by the increase of the height over gutter of a Colombian multi-tunnel greenhouse using a successfully two-dimensional computational fluid dynamics (CFD) model. The simulated numerical results showed that increasing the height of the greenhouse allows obtaining temperature reductions from 0.1 to 11.7 °C depending on the ventilation configuration used and the external wind speed. Likewise, it was identified that the combined side and roof ventilation configuration (RS) allows obtaining higher renovation indexes (RI) in values between 144 and 449% with respect to the side ventilation (S) and roof ventilation (R) configurations. Finally, the numerical results were successfully fitted within the surface regression models responses.

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Section: Renewal Index (Ri)supporting

confidence: 89%

Influence of the Height in a Colombian Multi-Tunnel Greenhouse on Natural Ventilation and Thermal Behavior: Modeling Approach

Villagrán

Flores²,

Akrami

et al. 2021

Sustainability

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“…It is also observed that the fixed vents in the roof region for this case function as air inlet areas over a region approximately in the lower 3/4 of the longitudinal section and an air outlet area approximately over the upper 1/4 of the longitudinal section in all the spans. This may indicate that the longitudinal slope generates on the fixed windows of the greenhouse roof regions positive pressure for the air inlet zones and negative pressure for the window section where there is an air outlet flow [52,53].…”

Section: Qualitative and Quantitative Characteristics Of Airflow Patternsmentioning

confidence: 99%

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

2021

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The use of covered structures is an alternative increasingly used by farmers to increase crop yields per unit area compared to open field production. In Latin American countries such as Colombia, productive areas are located in with predominantly hillside soil conditions. In the last two decades, farmers have introduced cover structures adapted to these soil conditions, structures for which the behavior of factors that directly affect plant growth and development, such as microclimate, are still unknown. Therefore, in this research work, a CFD-3D model successfully validated with experimental data of temperature and air velocity was implemented. The numerical model was used to determine the behavior of air flow patterns and temperature distribution inside a Colombian passive greenhouse during daytime hours. The results showed that the slope of the terrain affects the behavior of the air flow patterns, generating thermal gradients inside the greenhouse with values between 1.26 and 16.93 °C for the hours evaluated. It was also found that the highest indoor temperature values at the same time were located in the highest region of the terrain. Based on the results of this study, future researches on how to optimize the microclimatic conditions of this type of sustainable productive system can be carried out.

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“…Natural ventilation is the most important phenomenon to be controlled inside a protected agricultural structure, since it facilitates the exchange of mass and energy between the crop plants, the surrounding air inside the structure, and the external environment [15]. Therefore, in a structure that relies on natural ventilation as a method of climate control, it is necessary to ensure an adequate and uniform movement of air flow, which will guarantee that the microclimatic variables will remain within optimal levels for plant growth and development [16].…”

Section: Introductionmentioning

confidence: 99%

“…Four decades later, some researchers have proposed the use of Bernoulli's equation as a calculation method to estimate the amount of air that can circulate through a ventilation area, thus generating the basic theory of natural ventilation in greenhouses [26][27][28]. Similar methodologies were also proposed for other types of structures such, as screenhouses [16]. Currently, there are already calculation techniques that help to understand the behavior of natural ventilation, among these are: (i) mass balance with a tracer gas, (ii) indirect energy and mass balance methods, (iii) direct measurements of velocities and pressures at windows, (iv) visual methods on scale models, and (v) wind tunnel studies [17,29].…”

Section: Introductionmentioning

confidence: 99%

Research on the Microclimate of Protected Agriculture Structures Using Numerical Simulation Tools: A Technical and Bibliometric Analysis as a Contribution to the Sustainability of Under-Cover Cropping in Tropical and Subtropical Countries

2021

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The use of protected agriculture structures in tropical and subtropical countries is the main alternative for intensification of agricultural production selected by producers. In general, in these regions, passive and plastic-covered structures predominate, with natural ventilation as the only method of climate control. This phenomenon has been widely studied in different types of structures using computational fluid dynamics (CFD) simulation. Therefore, this review aimed to collect and analyze the publications generated in this field of knowledge between 2010 and 2020. The search for information included the main academic databases available on the web and the analysis was carried out using bibliometric techniques, from which it was possible to identify details inherent to the scientific production, such as countries of origin, main authors, journals, and citations. Likewise, a detailed breakdown of the relevant technical information of the three phases of numerical simulation, such as preprocessing, processing, and postprocessing, was carried out. A compilation of 118 papers published in 65 journals, written by 256 authors, originating from 24 countries was achieved, where it was evident that Mexico and Colombia were the countries with the highest scientific production in the last decade. These papers analyzed, together, a total of 17 different types of structures where polyethylene-covered greenhouses predominated, with steady state simulations, for daytime climate conditions and without the presence of crops. Within the current and future research trends, the predominance of studies analyzing passive climate control methods, new models of insect-proof mesh-house structures, and, finally, studies focused on the structural analysis of greenhouses was found.

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Determinación de las tasas de ventilación natural en un invernadero mediante modelos teóricos y gases trazadores

Cited by 4 publications

References 17 publications

Influence of the Height in a Colombian Multi-Tunnel Greenhouse on Natural Ventilation and Thermal Behavior: Modeling Approach

Influence of the Height in a Colombian Multi-Tunnel Greenhouse on Natural Ventilation and Thermal Behavior: Modeling Approach

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

Research on the Microclimate of Protected Agriculture Structures Using Numerical Simulation Tools: A Technical and Bibliometric Analysis as a Contribution to the Sustainability of Under-Cover Cropping in Tropical and Subtropical Countries

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