Exergy, drying kinetics, and performance assessment of Solanum lycopersicum (tomatoes) drying in an indirect type domestic hybrid solar dryer ( ITDHSD ) system

Abstract

An indirect type domestic hybrid solar dryer (ITDHSD) has been fabricated and its thermal performance, exergy, and drying kinetics of tomatoes slice were analyzed. Moisture in tomato slices was dried from 95% to 9% (wet basis) in 10 h of solar drying in ITDHSD during the winter season. Drying curve obtained was fitted with different existing empirical models and Prakash and Kumar model was found suitable for tomatoes drying in ITDHSD. Overall drying efficiency of the system was estimated as 41.05%. Furthermore, with variable mass flow rate, exergy efficiency values varied from 32.86% to 58.26%. Overall exergy efficiency was 46% during tomato drying experimentation. Various exergy sustainability indicators have been estimated in this study to observe improvement potential in the system. Improvement potential, waste exergy ratio, and sustainability index of the ITDHSD system was estimated in the range of 0.006966–0.065984, 0.41–0.67, and 1.55–2.39, respectively. Therefore, ITDHSD system provides a better option to domestic users for drying food crops in less duration and with no deterioration. This piece of work will be helpful for researchers in performing exergy analysis, drying kinetics, and performance assessment on hybrid solar dryers. Novelty impact statement All available literature on tomato drying in a compact sized dryer lacked in evaluation of the exergy analysis of solar PV module used to run a fan. Moreover, an essential factor of equivalent moisture content is also neglected in the literature during calculation of moisture ratio, which cannot be neglected in drying high moisture crops in tropical areas with high relative humidity. In the present experimental study, a new hybrid solar dryer system design has been developed and fabricated for domestic users.