Abstract In East Africa, post-harvest loss of fresh perishable fruits is enormous, causing recurrent seasonal deficits. In response, a modified passive-mode hybrid solar dryer hereafter called; ‘an Improved Solar Dryer (ISD)’, was developed as a potential low-cost technology alternative for drying fruits in Uganda. An improved PV-assisted hot air dryer using active-mode hybrid solar dryer hereafter called; ‘Solar Photovoltaic and Electric (SPE)’ was also fabricated. The ISD dryer utilises freely-available solar energy to dry the produce. In contrast, the SPE dryer uses both solar photovoltaic and electricity sources. In this study, the drying performance of the ISD and SPE dryers were performed and compared to that of the traditional open sun drying (OSD) method. Relative to the OSD method, the economic performance of the ISD and SPE dryers was analysed. The drying performance results show that the mean drying air temperatures achieved by the ISD and SPE dryers were 31.9 and 41.1 °C respectively; relative to the 27.6 °C for the OSD method. On average, the thermal energy attained by the ISD and SPE dryers were 3551 and 5757 Watts (W) respectively, as compared to 2952 (W) obtained for the OSD method. It took the ISD and SPE dryers 10 and 18 h to effectively dry the fruit (pineapple) products, respectively as opposed to the 30 h taken by the OSD method. The results confirm the superior performance of the ISD and SPE dryers than the OSD method. Results for the economic performance analysis show more reduced costs of drying the products using the ISD than the SPE dryer. Similarly, the pay-back period for the ISD was 2.4 times shorter than that of the SPE dryer. Joint results for economic analysis and drying performance confirm the ISD as a better drying technology than the SPE dryer in the context of the resource-constrained farmers/agro-processors without electricity in Uganda and East Africa.

中文翻译：

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用于干燥东非水果的新型混合被动模式和主动模式太阳能干燥机的干燥性能和经济分析

摘要 在东非，新鲜易腐烂水果的收获后损失巨大，导致经常性的季节性短缺。作为回应，以下称为改进的被动模式混合太阳能干燥机；“改进型太阳能干燥机 (ISD)”是在乌干达开发的一种用于干燥水果的潜在低成本技术替代方案。使用主动模式混合太阳能干燥机的改进型光伏辅助热风干燥机，以下简称；还制造了“太阳能光伏和电力（SPE）”。ISD 干燥机利用免费的太阳能来干燥农产品。相比之下，SPE 干燥器同时使用太阳能光伏和电源。在本研究中，对 ISD 和 SPE 干燥器的干燥性能进行了测试，并与传统的露天晒干 (OSD) 方法进行了比较。相对于 OSD 方法，分析了 ISD 和 SPE 干燥器的经济性能。干燥性能结果表明，ISD 和 SPE 干燥器达到的平均干燥空气温度分别为 31.9 和 41.1 ℃；相对于 OSD 方法的 27.6 °C。平均而言，ISD 和 SPE 干燥器获得的热能分别为 3551 和 5757 瓦 (W)，而 OSD 方法获得的热能为 2952 (W)。与 OSD 方法需要的 30 小时相比，ISD 和 SPE 干燥机分别需要 10 和 18 小时才能有效干燥水果（菠萝）产品。结果证实了 ISD 和 SPE 干燥器的性能优于 OSD 方法。经济性能分析的结果表明，使用 ISD 干燥产品比使用 SPE 干燥器降低了更多的成本。同样，ISD 的回收期为 2。比 SPE 干燥器短 4 倍。经济分析和干燥性能的联合结果证实，在乌干达和东非资源受限的农民/农业加工商没有电力的情况下，ISD 是比 SPE 干燥器更好的干燥技术。