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Verification of Computational Fluid Dynamic Temperature Simulations in a Full-Scale Naturally Ventilated Greenhouse

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Transactions of the ASAE. Vol. 44(1): 119-127 . (doi: 10.13031/2013.2303) @2001
Authors:   I.-B. Lee, T. H. Short
Keywords:   CFD model, Multi-span greenhouse, Natural ventilation, Double poly, Gutter-connected greenhouse, Controlled-environment agriculture
-1), respectively, for a west wind of 2.5 m s-1 and an east wind of 0.9 m s-1. The maximum recorded air temperature difference between inside and outside the greenhouse was 3.5°C during the hottest (34.7°C) recorded sunny day during the study. The air temperatures across the 33 m × 35 m greenhouse were acceptably uniform, with the maximum temperature difference among six inside air temperatures being only 2.9°C. The results indicated that the CFD numerical model was a very good tool for evaluating the relative performance of the natural ventilation system.

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Incompressible, isothermal airflows in a naturally ventilated multi-span greenhouse with plants were analyzed numerically by a computational fluid dynamics (CFD) simulation program using the standard k-ε turbulence model. The air temperature distributions of the CFD model showed a maximum error of ±3.2% for west and east winds compared to air temperatures measured in the greenhouse for similar conditions. The CFD results indicated that the natural ventilation rates of the greenhouse were 0.9 and 0.3 greenhouse volumes per minute (G.V. min-1), respectively, for a west wind of 2.5 m s-1 and an east wind of 0.9 m s-1. The maximum recorded air temperature difference between inside and outside the greenhouse was 3.5°C during the hottest (34.7°C) recorded sunny day during the study. The air temperatures across the 33 m × 35 m greenhouse were acceptably uniform, with the maximum temperature difference among six inside air temperatures being only 2.9°C. The results indicated that the CFD numerical model was a very good tool for evaluating the relative performance of the natural ventilation system.

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