Comprehensive Analysis of Solar Dryer with a Natural Draught

Abstract

ABSTRACT A solar dryer has been examined critically by using a constant drying model. The effect of the dynamic losses, intrinsic properties such as thermodynamic, hydrodynamic and psychometric factors, and natural draught during the practical application of the solar drying unit has been investigated. Carson and Moses, and the dynamic and static pressure correlations with the flow field have been used to determine the flow pattern inside the collector, the drying chamber, and the chimney. The energy allocation throughout the drying process has been evaluated by a Sankey diagram. The psychrometric calculation has been made by applying the steady-state-steady flow conditions (SSSF) on the carrier fluid (air). The average drying rate for the given design is 0.31 kg·h−1. The overall drying system efficiency is found to be 19%. The net static-regain (S.R) in the ducting system due to the sudden expansion is 2.22 N·m−2. The plume height for an efficient dilution of outgoing hot air is 1.17 m in addition to the given design. The flat plate collector efficiency for the given design was 26%. The surface temperature of the specimen should not be more than 321 K during a constant rate period. The pressure loss due to sudden contraction was found to be 73.48% lower than that of sudden expansion. Drying consumed 0.3% of the global irradiance for the drying purpose, whereas 57% of net received energy was absorbed by carrier fluid. The study encompassed the variability in the input that influence the performance of the solar collector since quantitative workout might not be effective unless the rheology is considered.