Exploring the performance of an indirect solar dryer by combining three augmentation approaches (trapezoidal absorber, shot blasting, and pebble stone)

• Published in: Journal of energy storage Vol. 78; p. 110109
• Main Authors: GaneshKumar, Poongavanam, Sundaram, P., Sathishkumar, A., Vigneswaran, V.S., Chopra, Twisha, Thakur, Uttkar, Kim, Seong Cheol, Ramkumar, Vanaraj
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2024
• Subjects: Corrugation; Pebble stone; Shot blasting; Solar air heater; Solar dryer; Thermal energy storage; Thermal energy storage; Shot blasting; Pebble stone; Corrugation; Solar air heater; Solar dryer
• ISSN: 2352-152X
• DOI: 10.1016/j.est.2023.110109

The shelf life of food products can be increased by reducing their moisture content with the aid of solar dryers. However, the poor efficiency of solar collectors increases the time and energy required for drying the food crops. Hence, the present work aims to overcome the above bottleneck by employing corrugated shot-blasted absorbers in solar air heaters and comparing their performance with flat plate solar air heaters. Subsequently, the drying kinetics of bitter gourd and tapioca cassava were subject to experimental investigation using indirect solar dryers in their natural mode, aiming to assess the dryers' overall performance. The experiments revealed that the average thermal efficiencies of the SAHs equipped with flat plate absorber plates and corrugation with shot-blasted absorber plate treatment displayed variations ranging from 39.05 to 53.12 % while maintaining a constant MFR of 0.02 kg/s. The average exergy efficiency of the FPAP is 1.103 % and the CSB absorber plate is 1.755 % with a constant flow rate of 0.02 kg/s. The research findings indicate that the CSBAP (surface-improved SAH) demonstrates a higher heat-absorbing capacity when compared to the FPAP SAH. The utilization of the CSBAP design along with the incorporation of pebble stone results in a greater ability to efficiently absorb and retain heat when compared to the traditional FPAP design with a shot-blasted surface. The inclusion of pebble stones in the drying process, as observed in Case II for Tapioca cassava, led to a remarkable improvement in drying efficiency by approximately 36 % when compared to Case I. Furthermore, the drying efficiency for bitter gourd in Case IV experienced a notable improvement of around 30 % when pebble stones were integrated into the drying process, in contrast to Case III. Eventually, the experimental results specified that the carbon credits accrued for the CO2 mitigated by the FPAP and CSBAP systems in the natural convection mode were calculated to be approximately 226.48 and 308.11 Rate $/year, respectively. These alterations synergistically contribute to enhancing the SAH's effectiveness and effectively utilizing solar heat directly contributes to reducing greenhouse gas emissions and, subsequently, the carbon footprint. •Developed an indirect solar dryer with surface modification technique for rural products.•Flat plate and corrugation with shot blasting SAH were investigated.•Pebble stone as a thermal storage medium helped for continuous after sundown.•The payback period of the FPAP and CSBAP-SAH with TES was calculated to be 0.3866 and 0.544 years.•CO2 emission, mitigation, and carbon credit were enhanced in CSBAP-SAH compared with FPAP.