Abstract
ABSTRACT The thermal efficiency of naturally ventilated greenhouses is limited due to the permanent exchange of air through the vents, especially during the night hours. The objective of the work consisted in evaluating a system of inflatable air ducts that close the roof vents during the night as a strategy to reduce the energy loss during these hours. For the development of this work, we applied the computational fluid dynamics (CFD) method to a passive multi span greenhouse operating under the dominant nocturnal climatic conditions of the Bogota savannah (Colombia). The results indicated that the use of the ducts system reduces the value of the negative thermal gradient between the interior and exterior of the greenhouse. The CFD model used was validated by comparing experimental data and simulated data and by calculating goodness-of-fit parameters, finding that the numerical model predicts satisfactorily and with an adequate degree of fit the actual thermal behavior of the greenhouse evaluated.
Highlights
In Colombia, greenhouse horticultural production has an approximate area of 10000 ha, dedicated almost exclusively to cut flowers and tomato crops
Espinal-Montes et al (2015) developed a work based on a numerical model computational fluid dynamics (CFD) 3D with the objective to evaluate the nocturnal thermal behavior of a passive Mexican greenhouse, the main results of this study reported the generation of the phenomenon of thermal inversion with average gradients of -0.8 and -3.1 °C for the configuration of open vents and for the configuration totally closed respectively
In order to explore night-time climate control alternatives that improve the thermal behavior of naturally ventilated greenhouses, the objective of this paper is to evaluate a system of inflatable air ducts that close the fixed roof openings during the night in a multi-tunnel type greenhouse located in the savannah of Bogotá
Summary
In Colombia, greenhouse horticultural production has an approximate area of 10000 ha, dedicated almost exclusively to cut flowers and tomato crops. The climate control is limited to the total closure of the side vents, aiming at keeping most of the energy gained during the day and maintaining as high as possible the temperature of the cultivation area. In this way, the objective is to prevent the thermal inversion of the greenhouse, a phenomenon in which the temperature of the greenhouse is lower than that of the surrounding outdoor air (Villagrán & Bojacá, 2019a).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
