Design and construction of a small scale tomato humidifier.

Abstract

Long shelf life of tomatoes during storage can be induced by reduction in the postharvest losses. These losses are as a result of factors such as high temperature and low relative humidity, Pathological infection and mechanical injuries caused during postharvest handling of tomatoes. The purpose of the study was to develop a humidifier for tomatoes that maintains moisture content, controls storage temperatures, keeps freshness and maintains the quality of tomatoes as a way of extending the shelf life. The study objectives were to design the components of the humidifier, construct the prototype, test for the performance of the prototype and carry out an economic evaluation of the humidifier. These were done and achieved by using the knowledge of engineering drawing and solid edge software to come up with the sketches of the drawings for the design. Measurements were done using tape measures and square rules so as to come up with the required material sizes and dimensions from which the construction was done and they included joining through hammering and tightening of the wire nettings. The study was limited to designing, constructing, testing for the performance, and economic evaluation of a humidifier. The tests carried out were temperature tests for both ambient air and moist air in the humidifier and the physical tests on tomatoes stored in the ambient and the humidifier. Results for testing were tabulated for different times of the day to evaluate the performance of the humidifier by calculating the humidifying efficiency. Discussion, conclusion and recommendations were derived from the testing results and finally an economic analysis of the humidifier was performed through which a payback period was used as the evaluation method.