design, installation and evaluation a automatic atmosphere controlled cold storage

one way to increase the shelf life of agriculture products is using of controlled atmosphere storages. in order to obtain the controlled gas components, an equipped cold store with cooling system and atmosphere controller system designed and constructed. the injection of co2, o2 and n2 were controlled automatically into the store by programable logic control (plc). the store was a laboratory refrigerator with 780 litters' capacity. three 10 kg capsules were feeding the gases of co2, o2 and n2. three sensors were sensing the concentration of co2 and o2 and air pressure in the store and three electrical value were controlled the injection of co2, o2 and n2. finally, the gas injection controlled system was evaluated in three components of co2, o2 and n2. the results showed that the gas injection controlled system was performed with 17.55 average error percentage. the average error of cooling system related to the adjusted temperature was 19.87%.