Abstract

FLORES-VELAZQUEZ, Jorge; LOPEZ-CRUZ, I. Lorenzo; MEJIA-SAENZ, Enrique  and  MONTERO-CAMACHO, J. Ignacio. Climate performance evaluation of a greenhouse in central México using computational fluid dynamics (CFD). Agrociencia [online]. 2014, vol.48, n.2, pp.131-146. ISSN 2521-9766.

One of the main economic activities in México is horticulture production in protected environments for the US market. The area under protected agriculture increases about 20 % yearly, notwistanding production is restricted by high and low temperatures during specific periods. This poses the need for a cooling system. Efficient natural ventilation is an effective method for controlling climate, but its description is complex and requires more knowledge of the process. The objective of this study was to visually represent the air flow and temperature distribution in a cenital greenhouse with 10 spans (110x90x4.7), typical in central Mexico, by posing and solving the physical model of air movement. A totally developed (LAI=4) tomato (Lycopersicon esculentum Mill.) crop was simulated. The model uses the computational fluid dynamics (CFD) approach and was structured and validated in the installations of the Institut de Recerca i Technolgía Agroalimentaries (IRTA) de Cabrils, Barcelona, Spain, from 2009 to 2010. Analysis of the results indicates significant differences in air flow due to the direction of window opening. The 3-Dimensional numerical analysis (CFD) enabled overall visualization of the spatial distribution of the climate inside the greenhouse and its climatic deficiencies. For wind speeds of 3 m s^-1 in the first five spans, lateral ventilation is more important than roof ventilation because of wind or thermal effects. The combination of lateral and roof window opening increases thermal uniformity in the greenhouse by 30 % due to greater exchange flow through the roof windows, contributing fresh air to the interior, which maintains maximum gradients of 5-8 K.

Keywords : cooling system; wind effect; gas tracer; heat gradient; Lycopersicon esculentum Mill.