Dehydration of red chilli using an indirect type forced convection solar dryer integrated with thermal energy storage

Abstract

• A solar air drier is proposed for food preservation. • A double pass solar air heater integrated with thermal storage is fabricated and experimentally tested. • Exergy and energy analysis is carried out by drying 5Kg of red chilli. • The experimental result are compared with previous published work. A food preservation method called drying is used to take out extra moisture from a product so that it can be stored for a long time without losing quality. Developing affordable and energy-efficient solar dryers is still a challenge, but solar drying has become a common practice in developing nations as a way to overcome the limitations of traditional open air drying. Therefore, it is essential to find ways to increase solar dryer efficiency. In order to improve performance and thermal energy storage inside the drying chamber by drying red chilies, the main objective of this study is to design, develop, and test the performance of an indirect solar dryer that uses a double pass solar air heater (DPSAH) in combination with baffles. The drier is designed and fabricated to dray 5 Kg of red chillies. The findings show that the heater's outlet temperature ranged from 33.9°C to 70.9°C, and that the collector's thermal and exergy efficiencies ranged from 9.4 % to 52.3 % and 2.35 % to 0.012 %, respectively. The drying chamber's average thermal efficiency was 31.1 %, and its average exergy inflow, outflow, and exergy efficiency were 11.4 W, 5.2 W, and 50.7 %, respectively. The addition of phase change material (PCM) to the drying chamber reduces variations in air temperature, enabling nearly constant air supply to the chamber. Red chilli dried in 29 and 56 hr, respectively, and its moisture content decreased from 81 % (w.b.) to 11.7 % (w.b.) and 14.32 %. After doing an economic study, it was concluded that the dryer would require a payback period of 2.04.

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