Analysis of the Thermal Behavior of a New Structure of Protected Agriculture Established in a Region of Tropical Climate Conditions

Abstract

Determining airflow patterns and their effect on the distribution of microclimate variables such as temperature is one of the most important activities in naturally ventilated protected agricultural structures. In tropical countries, this information is used by farmers and decision makers when defining climate management strategies and for crop-specific cultural work. The objective of this research was to implement a validated Computational Fluid Dynamics (CFD) model in 3D to determine the aerodynamic and thermal behavior of a new protected agricultural structure established in a warm climate region in the Dominican Republic. The numerical evaluation of the structure was carried out for the hours of the daytime period (6–17 h), the results found allowed to define that the CFD model generates satisfactory predictions of the variables evaluated. Additionally, it was found that airflow patterns are strongly affected by the presence of porous insect screens, which generate moderate velocity flows (<0.73 m s−1) inside the structure. It was also identified that the value of the average temperature inside the structure is directly related to the air flows, the level of radiation and the temperature of the outside environment.

Thermal Simulation of a Screenhouse Proposed for Fruit and Vegetable Production in the Lowlands of Panama

“…It is worth mentioning that the qualitative characteristics of the air flow patterns discussed in this section are influenced by the loss of impulse presented on the air flow due to the presence of the anti-insect screen. Likewise, the flow pattern inside the IP-SH is driven by the wind and thermal components of natural ventilation, this type of results has already been discussed and verified in similar works such as those developed by Flores-Velá zquez & Montero [10] and Villagrá n & Rodriguez [31]. Results that have been experimentally validated as reported by Teitel et al [8,49].…”

“…This is a semi-empirical model based on the transport equations that solve the kinetic turbulent energy ε and the dissipation of this energy per unit volume ε. The kε has been the most applied and widely validated model in greenhouse and screenhouse airflow studies showing to be computationally efficient while providing realistic solutions [14,31]. Boussinesq's model was considered in order to simulate variations in air density inside the screenhouse generated by temperature changes.…”

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

“…This work identified that a greenhouse-shade-screen hybrid structure in semi-arid climatic conditions showed a lower thermal gradient compared to a greenhouse with a plastic cover, enabling vegetable production. It should also be mentioned that when solar radiation data for the study region are not available, these values can be obtained from the solar calculator of the Ansys Fluent software, and these values from the solar calculator can be coupled to any of the radiation models available in the software [4]. Finally, these coupled simulations in recent years have allowed the evaluation of different covering materials, which helps producers or decision makers to select the covering material with the best microclimate conditions, better PAR radiation utilization, and higher thermal efficiency in protected agriculture structures [135].…”

“…This, together with the high vulnerability of agriculture due to accelerated climate change, has become a serious threat to the food security of nations, generating new challenges to agricultural productivity [3]. Therefore, there is an explicit need to increase food production by approximately 70% in the coming years, and it is also necessary to develop production intensification strategies to provide technical solutions [4]. The increase in food production must also be carried out with less natural resources, such as water and soil, which is why agriculture under cover or in greenhouses has been proposed as one of the main production alternatives [5].…”

“…Finally, there is the postprocessing phase, where qualitative and quantitative analyses of the results obtained in the numerical simulations can be performed [23]. However, these simulations must be validated before implementation with experimental methodologies or with theoretical comparisons based on the execution of the numerical models or with comparisons of previously performed work [4,12,34].…”