3D Numerical Analysis of the Natural Ventilation Behavior in a Colombian Greenhouse Established in Warm Climate Conditions

Abstract

Global food production and availability in hot climate zones are limited by biotic and abiotic factors that affect agricultural production. One of the alternatives for intensifying agriculture and improving food security in these regions is the use of naturally ventilated greenhouses, an alternative that still requires information that allows technical criteria to be established for decision-making. Therefore, the objective of this work was to study the spatial distribution of temperature and relative humidity inside a greenhouse built in the Colombian Caribbean. The methodological approach included the implementation of an experimentally validated 3D numerical simulation model. The main results obtained allowed to determine that the airflows generated inside the greenhouse had average velocities below 0.5 m/s and were mainly driven by the thermal effect of natural ventilation. It was also found that the gradients generated between the interior of the structure and the exterior environment presented values lower than 2.0°C for temperature and −6.3% for relative humidity. These values can be considered low in comparison with other structures evaluated in other regions of the world where the gradients can reach values higher than 10°C and 13% for temperature and relative humidity, respectively.

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

“…The non-grey model was activated by dividing the radiative spectrum into two specific wavelengths, the first being the solar radiation length (0.4-2.4 µm) and the second the long wavelength (2.4-100 µm). Likewise, in order to simplify the resolution of the 3D CFD model, no crops were included, in order to speed up the numerical calculation and establish the behavior of air flow and temperature under the worst possible scenario, which are conditions where there are no plants present, a scenario where a large part of the incident radiation on the interior of the greenhouse is converted into heat, which generates an increase in the temperature of the interior air [2].…”

“…Finally, it is important to mention that the results obtained in this research are a relevant technical input that will allow future microclimatic optimization strategies to manage the temperature conditions inside roof structures built on slope soil. Thermal heterogeneity inside this type of structure is an undesirable condition that puts at risk the sustainability of agricultural production in the future year, considering the increase of temperatures due to climate change as a serious threat in the tropical region [1,2].…”

“…Cultivation systems in greenhouses are becoming one of the most widely used alternatives for the sustainable intensification of food production such as fruit and vegetables in many countries [1,2]. These agricultural production systems allow the increase of crop yields per unit area and optimization of water management per unit of product, compared to open field crops [3].…”

“…In this natural region there are approximately 14 million hectares with soils suitable for agriculture, although approximately 75% of these areas are located in hillside regions [36]. In these regions, for about a decade, different roof structures have been established, mainly greenhouses and mesh houses, where their microclimatic behavior is still unknown [2]. The microclimate variables inside the greenhouse, such as temperature and relative humidity, are directly related to processes such as transpiration and photosynthesis; processes that affect the growth and development of the plants and consequently the final production obtained [37].…”

“…The microclimate variables inside the greenhouse, such as temperature and relative humidity, are directly related to processes such as transpiration and photosynthesis; processes that affect the growth and development of the plants and consequently the final production obtained [37]. Therefore, knowledge of microclimatic behavior allows the establishment of cultural management practices such as irrigation and fertilization [2].…”