Solar drying systems for domestic/industrial purposes: A state-of-the-art review on topical progress and feasibility assessments.

Abstract

In this era of commercialization, energy scarcity and food security are two of the major global challenges owing to the continuously growing population. The significant post-harvest food loss witnessing alarming hunger statistics have motivated the contributors and several decision-makers to put their serious efforts towards promoting food security globally. Solar drying is identified as a widely accepted, qualitative, and sustainable food preservation scheme. This article aims to review various strategic advancements of different solar energy-based drying systems comprehensively; those are being utilized globally for domestic and commercial purposes.The article explores various parameters affecting the solar dryer performance and details different methods used for performance improvement. In addition to the comprehensive discussions on the pre-eminent qualitative impacts of solar dryers, this article takes an opportunity to highlight their socio-economic and environmental aspects, provides comparative assessment through case studies and discusses the current challenges associated with solar dryer. The solar irradiation intensity, air-flow, dryer geometry, and mode of operations are recognized as crucial parameters affecting the performance of solar dryers.Amongst various categories of solar drying methods, the forced convection-assisted mixed-mode dryers are observed as most efficient ones.Application of latent heat energy storage materials is suggested as suitably efficient performance enhancement techniques for different solar drying systems, enabling their applications in remote areas with extended operational periods during nights or cloudy seasons also. The favourable qualitative, environmental, and social aspects of several solar drying strategies confirm their viability to different domestic as well as industrial applications. However, higher initial costs, and hence; extended payback periods may limit their adoptions by smallholder farmers. However, the multiple-season applications of these equipment may result in improved payback scenarios by more than 50%.