Design & construction of a low-cost storage system for fruits and vegetables

Abstract

Horticultural produce begins deteriorating when separated from its source of water which is the plant. This calls therefore for increased means of handling at different stages before consumption. In Uganda today, some efforts have been put into consideration through development of coldrooms by people like eco-life Uganda. However, less efforts have been put into the local markets to aid in the storage and display of the produce. This has led to adoption of loss effects where the vendors sell the produce at a lower price just to survive. This project aimed at designing, constructing and testing a low-cost storage system for fruit and vegetable vendors within Uganda. The main goal was to increase shelf-lives of produce in markets and hence more sales resulting into higher profits. The system was designed to hold a capacity of 50kg, however at the end of the construction it would hold about 30kg. It works on the principle of vapor- compression with a manual temperature regulator which aids in modulating the space temperature of the space. The storage system is made from galvanized steel so as to reduce on the rate of rusting. The insulator material used was Styrofoam which is so cheap and locally available since it is regarded as waste by most people. The system has an air inlet between the display door and window so to minimize odor in the system when power is off. This air gap also minimizes compressor work compared to the available fruit and vegetable display systems. The system has a glass door and window to aid viewing of what is inside the system. The system’s source of power is hydro-electricity however solar energy can also be incorporated onto it. The system was tested for a period of 12 days and it was running for 7-9 hours a day. From the tests, it was observed that the shelf-life of the Sukuma wiki was increased by 2 days when stored between 11.6-13.70C. This was in comparison to the storage of the Sukuma wiki under ambient conditions. The Sukuma wiki stored in the system started to change color in the system on day 5. When put out of the system it completely changed color after 3 days. The shelf-life of the tomatoes was increased from 5 days to 10 days when stored between 14.7- 15.70C. This was because from observation, the tomatoes stored in ambient conditions started to rot at day 3 and they were completely spoilt on day 5. For the tomatoes stored in the system, they stayed firm even on day 10. When placed out of the storage system, they stayed firm for an extra 2 days before they started to deteriorate. The tests show that storing of fruits and vegetables at the required temperatures is essential as it increases shelf-life and therefore the vendors are able to sell more and thus earning more profit. The economic analysis shows that 42.31% profit of tomatoes is lost due to poor means of storage hence validating the need for improved storage systems with in the markets. This therefore calls for more research and need to develop better systems out of cheap material to curb the problem.