Studies on the Optimization of Air Flows in Apple Storage Rooms

Air circulation is one of the most important parameters during fruit storage, as it has a crucial influence on the climate within the storage room. We investigated the impact of measures to optimize storage room air flows on air and fruit temperatures, relative humidity (RH) distribution and air velocity within and between fruit bins, weight loss of the fruit, and fruit quality at storage outturn. Two identical commercial CA rooms (40 tons 'Jonagold' apples each), one with (optimized) and the other without (non-optimized) air deflectors and sealing-off of the evaporators, were equipped with sensors to measure fruit temperatures at different positions in the room. At the same positions, air velocity was measured at the beginning of storage with a hand held anemometer. Additionally RH was measured psychrometrically. Results showed lower air velocities in the room with optimized air flow, maybe due to more air turbulence in the non-optimized room, which can influence anemometer measurements, leading to higher measured air velocities. The optimized room had similar to 4% higher RH, a more uniform temperature distribution and 0.4 degrees C lower fruit temperature in the warmest part of the room. Weight loss tended to be slightly higher in the optimized room, maybe due to an increased evaporation resulting from the optimized air flow near the fruit surface. Fruit quality analyses at storage outturn did not show any differences between the two storage rooms.