CFD analysis of airflow uniformity in a Shipping-Container vertical farm

This study focuses on optimizing airflow uniformity at canopy level in a container-sized vertical farm. Adequate air movement and uniform growth environment play a crucial role in crop production, as they significantly influence plant growth. In fully closed plant production systems, various issues such as tip-burn, low transpiration, and hindered photosynthesis can arise due to insufficient air circulation. To address these problems, four different air distribution systems were simulated using overall control or localized control techniques. A computational fluid dynamics analysis was conducted to evaluate the performance of the proposed and iteratively improved designs. Key parameters, including air velocity, CV, as well as the percentage of probe points within or outside the recommended range were investigated to identify differences between designs. The results revealed that the localized control technique, where airflow was directed straight into the canopy along a layer length, was significantly better than providing additional airflow at the end of a shelf. Air inlets along the layer length provided optimal average air velocity (0.65 m/s) and moderate airflow uniformity (coefficient of variation = 33 %) in Case 3. However, the introduction of additional outlets resulted in significantly improved uniformity compared to a single outlet and showed the lowest coefficient of variation with only 10 % in Case 4. Optimal airflow uniformity through well-designed ventilation systems is crucial, and the findings of this study contribute to a vast pool of possible designs in container farms, guiding future advancements in optimizing environmental conditions.