Browsing by Author "Gunda, John"

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Design of a Cooling System Integrated with Ultraviolet Light for Preservation of Fruits and Vegetables at Variable Tropical Weather Conditions: A Case Study of Arusha, Tanzania
(AJOL, 2023-09-30) Gunda, John; Pogrebnoi, Alexander; Kichonge, Baraka
Post-harvest losses of fruits and vegetables pose significant challenges, especially in tropical climates. This study introduces the development and performance evaluation of a solar-powered evaporative cooling storage system integrated with ultraviolet light (UV) designed for preservation of perishable fruits and vegetables. The cooling chamber supplied with ultraviolet lamp was developed using locally available materials such as sisal, sponge, and bricks. The performance of the system was evaluated in terms of air temperature decrease, relative humidity increase, and evaporative cooling power capacity both for sunny and cloudy tropical weather conditions. The study reveals that activating the UV light considerably extends the shelf life of fruits and vegetables. The system was able to extend the shelf life of perishable products by up to 21 days when exposed to ultraviolet light and by 9 days when not exposed to ultraviolet light. On sunny days, active system operation leads to an average temperature reduction of 5.0 °C, along with a relative humidity increase of 23%. On the contrary, on cloudy days, the cooling impact diminishes slightly, resulting in temperature decrease of approximately 3.5 °C and relative humidity increase of 18%. These findings emphasize the potential of the solar-powered evaporative cooling system, combined with UV light treatment, as a viable approach to combat post-harvest losses in tropical environments.
Design of an evaporative cooling system integrated with ultraviolet light for preservation of fruits and vegetables at variable tropical weather conditions: a case study of Arusha, Tanzania
(NM-AIST, 2024-07) Gunda, John
Problems with fruits and vegetables spoiling after harvest are particularly acute in tropical regions. This research presents the design, construction, and performance assessment of a solar-powered evaporative cooling storage system incorporating ultraviolet radiation (UV) to preserve foods susceptible to spoilage. Local materials, including sisal, sponge, and bricks, were used to construct the cooling chamber with a UV bulb. We measured the system's efficiency in both sunny and overcast tropical weather conditions by looking at how much air temperature was reduced, how much relative humidity was increased, and how much electricity was used for evaporative cooling. According to research, fruits and vegetables may be kept fresh for much longer after activating the UV light. This method may keep perishable goods for up to 21 days under UV light and 9 days without. An average temperature drop of 5.0℃ and an increase in relative humidity result from active system operation on sunny days. In contrast, the cooling effect is minimal on overcast days, leading to a relative humidity rise of 18% and a temperature drop of around 3.5℃. Based on these results, a solar-powered evaporative cooling system with UV radiation treatment might be a good way to reduce tropical post-harvest losses.