Verification of computational fluid dynamic temperature simulations in a full-scale naturally ventilated greenhouse

Incompressible, isothermal airflows in a naturally ventilated multi-span gr eenhouse with plants were analyzed numerically by a computational fluid dyn amics (CFD) simulation program using the standard k-epsilon turbulence mode l. The air temperature distributions of the CFD model showed a maximum erro r of +/-3.2% for west and east winds compared to air temperatures measured in the greenhouse for similar conditions. The CFD results indicated that th e natural ventilation rates of the greenhouse were 0.9 and 0.3 greenhouse v olumes 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 dif ference between inside and outside the greenhouse was 3.5 degrees C during the hottest (34.7 degrees C) recorded sunny day during the study. The air t emperatures across the 33 m x 35 m greenhouse were acceptably uniform, with the maximum temperature difference among sir inside air temperatures being only 2.9 degrees C. The results indicated that the CFD numerical model was a very good tool for evaluating the relative performance of the natural ve ntilation system.