Development and Performance Evaluation of a Solar Dryer Integrated with Thermal Energy Storage Materials for Drying Agricultural Products

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Date

2025-03

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NM-AIST

Abstract

Passive solar dryers are essential in reducing post-harvest losses of vegetable and fruits particularly in developing countries in Africa. Most simple passive solar dryers are being developed in developing countries, but the challenge is the sporadic nature of solar energy, resulting in reduced performance and rendering them ineffective during periods without sunlight. In addition, Techno-economic analysis (TEA) and Life cycle assessment (LCA) have been neglected in most of the studies on solar dryers (SD). In this study, a novel solar dryer incorporating soapstone as a thermal energy storage (TES) system to prolong the drying time was designed, constructed, and evaluated for its performance in terms of TEA and LCA. Experiments were carried out to compare the performance of the developed dryer in two configurations: With and without thermal energy storage (TES) materials. The results were evaluated alongside open-sun drying (OSD) with 50 kg of fresh carrots as well as fresh pineapples on separate occasions. The drying durations were recorded as 12 hours for the dryer with TES, 23 hours for the dryer without TES, and 50 hours for OSD. Notably, the TES integrated dryer could provide energy for approximately 3–4 hours after sunset. The dryer was found to have a thermal efficiency of 45%, a collector efficiency of 43%, and a storage efficiency of 74.5%. The dryer combined with TES materials proved to be more efficient in retaining nutrients in the dried products compared to the dryer without TES materials and OSD based on proximate study. The economic analysis showed that the annual savings for the dryer's 20 years of operation are $ 9814.5 for pineapple and $ 9121.2 for carrots. The cumulative present worth was $ 62 232.7 for pineapples and $ 57 836.3 for carrots. It was found that the pineapples payback period was 1.5 years, whereas for carrots payback was 1.6 years. The LCA revealed that steel materials had higher environmental impact items in material extraction and fabrication compared to aluminum materials for both the midpoint and endpoint categories. Based on techno-economic TEA and LCA assessments, the fabricated solar dryer is economically feasible and environmentally friendly. Solar dryers incorporating soapstone have demonstrated potential as efficient technology for minimizing post-harvest losses especially in developing countries in Africa.

Sustainable Development Goals

SDG-2: Zero Hunger SDG-7: Affordable and Clean Energy SDG-8: Decent Work and Economic Growth SDG-9: Industry, Innovation, and Infrastructure SDG-12: Responsible Consumption and Production SDG-13: Climate Action

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