Using CFD to optimize the design of one layer storage system for tulip bulbs

Tulip bulbs to plant the next season are stored in boxes which are ventilated to a level of 500 or 300 m3 per m3 bulbs per hour to avoid high ethylene concentration between the bulbs. The boxes are positioned in an arrangement of 5-6 rows with 8-10 boxes per row, each one on a pallet (one layer system), with an adjusted large box containing a ventilator. In this study a commercial CFD code was used to investigate the distribution of airflow between the boxes and the potential energy saving by applying simple solutions, concerning the design of the air inlet area. Two different design variations of the one layer system were simulated and two sizes of tulip bulbs were considered. The results show that the average energy consumption for different configurations was 1.00 kW and 0.79 kW for the first and the second design respectively, regarding both tulip bulbs sizes. With smaller tulip bulbs energy consumption is 19.4% higher for Design-1 and 26.0% for Design-2. The best variations of both designs can achieve a minimum airflow per box of 79% of the nominal one, which is 300 m3/h per m3 of tulip bulbs. The Design-2 has proven to be more energy efficient since it needs -22% less energy to achieve the same minimum airflow.