Journal: Agri &Biosys. Eng 1(2), pp.73 - 80.
Author: I. B. Lee, T. H. Short, S. Sase, K. Lee
Abstract
Aerodynamics ina naturally ventilated multi-span greenhouse with plants was analyzed numerically by the computational fluid dynamics (CFD) simulation. To investigate the potential application of CFD techniques to greenhouse design and analysis, the numerical result of the CFD model were compares with the results of a steady-state mass and energy balance numerical model. Assuming the result of the mass and energy balance model as the standard, reasonable good areement was obtained between the natural ventilation rates compyted by the CFD numerical model and the mass and energy balance model. the steady-state CFD model during a sunny day showed negative errors as high as 15% in the morning and comparable positive errors in the afternoon. Such errors assumed to be due to heat storage in the floor, benches, and greenhouse structure. For a west wind of 2.5m/s, the internal nonporus shading screens that opened to the east were predicted to have a 15.6% better air exchange rate than opened to the west. It was generallt predicted that the presence of nonporous internal shading screens significantly reduced natural ventilation if the horizontal opening of the screen for each span was smaller that the effective roof vent opening.
Keywords: computational Fluid Dynamics, Greenhouse, Ventilation, Shading Screen
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