Evaluation of an improved indirect solar dryer for Curcuma Amada without and with stone chips as thermal energy storage: An investigation on kinetics, energy, exergy, quality and economic aspects

Abstract

The drying kinetics, energy, exergy, quality, and economic studies of a solar dryer with and without energy storage have been conducted. The original configuration of a solar air collector (SAC) has been modified by adding waste stone chips beneath the absorber plate. Data related to mass loss, solar radiation, and temperatures were gathered during the experiments in both the configurations. Curcuma Amada samples had initial moisture of 87.4 % and achieved an equilibrium moisture level of 4.4 % within 8 h in the dryer equipped with waste beverage canned absorber plate and storage (SDCWS) and for dryer without storage (SDCWOS) it took 26 h. Out of the eleven drying models tested, the Midilli and Kucuk model exhibited the most favorable fit for Curcuma Amada in both the experiments. The average efficiencies for the collector and dryer were 67.26 % and 21.88 %, respectively, in SDCWOS. In contrast, the efficiencies for the collector and dryer were 87.95 % and 29.63 %, respectively, in the SDCWS. Exergy parameters such as in, out, loss, efficiency, improvement potential, waste exergy ratio, and sustainability index were estimated for both the configurations. Quality analysis was further carried out for both SDCWOS and SDCWS in terms of total polyphenol content, total flavonoid content and color. The estimated energy payback periods were 1.7 years for SDCWOS and 0.47 year for SDCWS, considering a 20-year lifespan. In all assessed aspects, the SDCWS configuration showed more favorable outcomes. The results of this study have the potential to positively impact the sustainable advancement of agricultural drying techniques within rural areas.