Techno Economic Analysis of Refractance Window Drying of Fruits: A Case of Small-Medium Scale Agro Processors in Uganda

Abstract

Uganda produces a variety of fruits, vegetables and herbs with much of it going to waste because of limited post-harvest processing methods. Refractance window drying technology (RWDT) has a potential of producing high quality dried food products from fruits, vegetables and herbs. A techno economic analysis (TEA) was conducted to compare the processing potential of a new hybrid RWD model to existing fruit drying technologies in selected districts of Uganda. Technical and economic data was collected using in-depth interviews with small and medium scale dried fruit processors, farmers and exporters. Comparisons of the technical and economic parameters of the currently used dryers and the hybrid RWD were done to ascertain the competitiveness of hybrid RWD in the local market. Economic analysis was conducted using the cost benefit analysis and payback period tools. Findings indicated the solar box dryer was the commonest and cheapest dryer at USD. 163, while the UNIDO solar hybrid dryer model was the most expensive at USD. 58,378. The UNIDO solar hybrid dryer (USHD) had the highest loading capacity of 1,250 Kg compared to the hybrid RWD and solar box dryer that both had a loading of 30 Kg of whole pineapple per batch. The throughput for the different dryers was found to be 60 Kg, 7.5 Kg and 0.5 Kg for the USHD, RWD and solar box dryers respectively for a 10-hour production cycle. The drying time for the solar box dryer was 48 hours compared to 2 hours for the hybrid RWD and 10 hours for the USHD for pineapple flakes per batch. Additionally, the hybrid RWD presented more opportunities for producing a variety of high-quality dried products, including fruit dices, powders, leather and flakes. A recommendation is made for design modification for the hybrid RWD to increase effective drying surface area and throughput.