Design, Development, and Performance Evaluation of an Improved Indirect Solar Mango Dryer for Sustainable Post-Harvest Preservation in The Gambia
DOI:
https://doi.org/10.67303/jcit.v1i1.20Keywords:
Indirect solar dryer;, mango preservation;, renewable energy, post-harvest losses;, natural convection, agricultural engineering, food processing;, sustainable agriculture, solar dryingAbstract
Post-harvest losses of fresh mangoes remain a significant challenge to food security, rural livelihoods, and agro-industrial development in The Gambia. During the annual mango harvesting season, substantial quantities of fruit are lost because of rapid deterioration, inadequate preservation technologies, limited access to reliable electricity, and dependence on traditional open-sun drying methods. Although solar drying offers an environmentally sustainable alternative, many existing cabinet dryers exhibit poor airflow distribution, excessive humidity retention, uneven drying, and mould formation, reducing product quality and limiting adoption by rural processors. This study presents the design, development, and engineering evaluation of an improved indirect natural-convection solar mango dryer specifically adapted to the climatic conditions of The Gambia. The proposed system integrates a high-efficiency solar air collector, an insulated drying chamber, food-grade removable trays, a balanced natural ventilation system, and a vertical chimney with an adjustable damper to improve airflow and moisture removal. The dryer is designed to process 20–50 kg of fresh mango slices per batch, operating within an optimal drying temperature range of 50–65°C while maintaining continuous natural airflow. Engineering analyses include airflow modelling, chimney design, solar collector optimization, tray configuration, and material selection using locally available resources. The design emphasizes improved drying uniformity, reduced drying time, enhanced product quality, and effective prevention of mould development through controlled ventilation and moisture extraction. The proposed dryer provides a low-cost, energy-efficient solution suitable for smallholder farmers, cooperatives, and rural agro-processing enterprises. Beyond reducing post-harvest losses, the system contributes to renewable energy utilization, food security, rural income generation, and climate-resilient agricultural development in The Gambia. The study establishes a practical engineering framework for future prototype validation, performance testing, and commercialization of sustainable solar drying technologies for tropical fruit preservation across West Africa. The engineering design parameters and construction principles presented in this paper are derived from the prototype developed for research and field testing in The Gambia.
Downloads
References
[1] FAO, 'The State of Food and Agriculture,' Rome, Italy, 2023.
[2] World Bank, 'The Gambia Country Overview,' Washington, DC, USA, 2024.
[3] A. S. Mujumdar, Handbook of Industrial Drying, 4th ed. Boca Raton, FL, USA: CRC Press, 2015.
[4] J. A. Duffie and W. A. Beckman, Solar Engineering of Thermal Processes, 4th ed. Hoboken, NJ, USA: Wiley, 2013. DOI: https://doi.org/10.1002/9781118671603
[5] B. K. Bala, Drying and Storage of Cereal Grains. Wiley, 2017. DOI: https://doi.org/10.1002/9781119124207
[6] M. Fudholi et al., 'Review of solar drying systems,' Renewable and Sustainable Energy Reviews, 2015.
[7] D. Jain and G. N. Tiwari, 'Thermal aspects of cabinet solar dryer,' Solar Energy, 2004.
[8] J. Esper and W. Mühlbauer, 'Solar drying—An effective means of food preservation,' Renewable Energy, 1998. DOI: https://doi.org/10.1016/S0960-1481(98)00143-8
[9] N. K. S. Yahia, Postharvest Technology of Perishable Horticultural Commodities. Woodhead, 2019.
[10] S. Bechoff et al., 'Effect of drying on mango quality,' Journal of Food Processing and Preservation, 2018.
[11] F. P. Incropera, D. P. DeWitt, T. L. Bergman, and A. S. Lavine, Fundamentals of Heat and Mass Transfer, 8th ed. Hoboken, NJ, USA: Wiley, 2017.
[12] G. N. Tiwari, Solar Energy: Fundamentals, Design, Modelling and Applications. New Delhi, India: Narosa Publishing House, 2002.
[13] R. K. Rajput, Heat and Mass Transfer. New Delhi, India: S. Chand & Company Ltd., 2010.
[14] H. P. Garg and J. Prakash, Solar Energy: Fundamentals and Applications. New Delhi, India: Tata McGraw-Hill, 2000.
[15] C. J. Brooker, F. W. Bakker-Arkema, and C. W. Hall, Drying and Storage of Grains and Oilseeds. New York, NY, USA: Springer, 1992.
[16] A. B. Akoyeo, "Performance evaluation of an indirect solar dryer for agricultural products," Solar Energy, vol. 89, pp. 1–12, 2013.
[17] M. A. Ekechukwu and B. Norton, "Review of solar-energy drying systems II: An overview of solar drying technology," Energy Conversion and Management, vol. 40, no. 6, pp. 615–655, 1999. DOI: https://doi.org/10.1016/S0196-8904(98)00093-4
[18] M. A. Ekechukwu and B. Norton, "Review of solar-energy drying systems I: An overview of drying principles and theory," Energy Conversion and Management, vol. 40, no. 6, pp. 593–613, 1999. DOI: https://doi.org/10.1016/S0196-8904(98)00092-2
[19] S. Janjai and P. Tung, "Performance of a solar dryer using hot air from roof-integrated solar collectors," Renewable Energy, vol. 30, pp. 2085–2094, 2005. DOI: https://doi.org/10.1016/j.renene.2005.02.006
[20] A. El-Sebaii and S. Shalaby, "Solar drying of agricultural products: A review," Renewable and Sustainable Energy Reviews, vol. 16, no. 1, pp. 37–43, 2012. DOI: https://doi.org/10.1016/j.rser.2011.07.134
[21] International Renewable Energy Agency (IRENA), Renewable Energy Statistics 2023. Abu Dhabi, UAE: IRENA, 2023.
[22] African Development Bank (AfDB), African Economic Outlook 2022. Abidjan, Côte d'Ivoire: AfDB, 2022.
[23] Ministry of Agriculture, Livestock and Food Security (MoALFS), Agricultural Statistics Report. Banjul, The Gambia, 2022.
[24] National Environment Agency (NEA), State of the Environment Report. Banjul, The Gambia, 2021.
[25] S. C. Singhal and R. Gupta, Solar Drying Technology for Agricultural Products. New Delhi, India: Springer, 2019.
[26] M. Ratti, "Hot air and freeze-drying of high-value foods: A review," Journal of Food Engineering, vol. 49, no. 4, pp. 311–319, 2001. DOI: https://doi.org/10.1016/S0260-8774(00)00228-4
[27] R. H. Perry and D. W. Green, Perry's Chemical Engineers' Handbook, 9th ed. New York, NY, USA: McGraw-Hill, 2019.
[28] K. J. Chua and S. K. Chou, "Recent advances in drying technologies," Trends in Food Science & Technology, vol. 14, no. 12, pp. 519–528, 2003. DOI: https://doi.org/10.1016/j.tifs.2003.07.003
[29] M. S. Rahman, Handbook of Food Preservation, 2nd ed. Boca Raton, FL, USA: CRC Press, 2007.
[30] R. P. Singh and D. R. Heldman, Introduction to Food Engineering, 5th ed. London, U.K.: Academic Press, 2014. DOI: https://doi.org/10.1016/B978-0-12-398530-9.00001-2
[31] A. S. Mujumdar, Advanced Drying Technologies, 2nd ed. Boca Raton, FL, USA: CRC Press, 2009.
[32] H. K. Sharma, C. Sarkar, and C. Sharma, Postharvest Management and Processing of Fruits and Vegetables. Boca Raton, FL, USA: CRC Press, 2018.
[33] R. Kader, Postharvest Technology of Horticultural Crops, 3rd ed. Oakland, CA, USA: University of California Agriculture and Natural Resources, 2005.
[34] United Nations, Transforming Our World: The 2030 Agenda for Sustainable Development. New York, NY, USA: United Nations, 2015.
[35] Intergovernmental Panel on Climate Change (IPCC), Climate Change 2022: Impacts, Adaptation and Vulnerability. Cambridge, U.K.: Cambridge University Press, 2022. DOI: https://doi.org/10.1017/9781009325844
[36] G. H. Hossain and B. K. Bala, "Drying of hot chili using solar tunnel dryer," Solar Energy, vol. 81, no. 1, pp. 85–92, 2007. DOI: https://doi.org/10.1016/j.solener.2006.06.008
[37] A. K. Simate, "Optimization of mixed-mode and indirect solar drying systems," Renewable Energy, vol. 28, no. 3, pp. 435–453, 2003. DOI: https://doi.org/10.1016/S0960-1481(02)00041-1
[38] A. B. Datta, Heat Transfer in Food Processing Applications. Boca Raton, FL, USA: CRC Press, 2002.
[39] S. Kalogirou, Solar Energy Engineering: Processes and Systems, 2nd ed. London, U.K.: Academic Press, 2014.
[40] Gustavsson, J., Cederberg, C., Sonesson, U., van Otterdijk, R., and Meybeck, A., Global Food Losses and Food Waste: Extent, Causes and Prevention. Rome, Italy: FAO, 2011.
