Assessment of the pineapple drying with a forced convection solar-electrohydrodynamic dryer

Abstract

Drying assumes a pivotal role in the preservation of high-moisture products over extended durations. Despite the widespread utilization of solar dryers owing to their energy-efficient nature, they are often plagued by prolonged drying durations, subsequently impacting the quantity of dried products. This investigation endeavors to introduce an innovative technique aimed at augmenting the efficacy of solar drying processes. Specifically, the study integrates forced convection solar drying with electrohydrodynamic (EHD) drying. The experimentation entails the drying of pineapple slices conducted between December 2023 and January 2024 in Nakorn Pathom, Thailand. The pineapple slices, featuring a ring-shaped geometry, are subjected to varying corona voltages ranging from 7 to 10 kV. The findings reveal a direct correlation between the corona voltage and the diffusion coefficient of the pineapple slices, wherein an escalation in corona voltage leads to an elevation in the diffusion coefficient, consequently resulting in a reduction of moisture ratio during the drying process. Consequently, the novel drying approach exhibits superior efficiency compared to traditional solar drying techniques, particularly as corona voltages increase. Moreover, the study employs Buckingham-Pi terms to predict the fluctuations in the diffusion coefficient, yielding a diffusion coefficient function with an R2 value of 0.996. Subsequently, a novel kinetics model for the drying process is proposed, boasting an average R2 value of 0.98. This model is envisioned to serve as a vital tool for enhancing and advancing forced convection solar-EHD dryers in forthcoming industrial applications.