Design development and numerical characterization of indirect domestic hybrid solar dryer

Abstract

A novel design of domestic hybrid solar dryer system has been proposed newlineand analysed with Computational Fluid Dynamics (CFD) using Ansys Fluent 19.2 newlinesoftware under unload condition. Further, Experiments under unload and load conditions were performed at Delhi Technological University (DTU), Delhi in the newlinemonth of November 2021. From unload experimentation, thermal performance parameters namely thermal efficiency, HUF (heat utilisation factor) and COP (coefficient of performance) of solar collector in indirect type domestic hybrid solar dryer newlinewere evaluated. The maximum values of thermal efficiency, HUF, and COP were newlinenoted as 59%, 0.68, and 0.32 at 13:00 hours. The theoretical results were in fair newlineagreement with experimental results as evaluated using linear regression analysis. newlineMoreover, ITDHSD (indirect type domestic hybrid solar dryer) was found superior newlineto other developed solar dryers in terms of maximum collector thermal efficiency. newlineFrom experiments under load condition, various parameters such as thermal newlineperformance, exergy and drying kinetics of tomato slices were analysed. Moisture newlinein tomato slices was dried from 95% to 9% (wet basis) in 10 hours of solar drying newlinein ITDHSD during the winter season. Drying curve obtained was fitted with different existing empirical models and Prakash and Kumar model was found suitable for newlinetomato drying in ITDHSD. Overall drying efficiency of the system was estimated newlineas 41.05%. Furthermore, exergy efficiency values varied from 32.86% to 58.26% newlinewith variable mass flow rate. Overall exergy efficiency was 46% during tomato newlinedrying experimentation. Various exergy sustainability indicators have been estimated in this research work and the primary aim was to observe improvement potential in the system. Improvement potential, waste exergy ratio and sustainability newlineindex of the ITDHSD system were estimated in the range of 0.006966 - 0.065984, newline0.41 - 0.67, and 1.55 - 2.39, respectively. newline