Thin layer drying characteristics of curry leaves (Murraya koenigii) in an indirect solar dryer

In this work, the thin layer drying characteristics of curry leaves (Murraya koenigii) has been studied in an indirect forced convection solar dryer with constant air mass flow rate of 0.0636 kg/s. Twelve thin layer drying models were tested for its suitability to describe the drying characteristics of curry leaves. The dryer has reduced the initial moisture content of curry leaves from 67.3% (wet basis) to the final moisture content of 4.75% (wet basis) in 3.5 hours. The pickup efficiency of indirect solar dryer for drying curry leaves was varied between 4.9% and 23.02%. Based on the statistical parameters, the Modified Henderson and Pabis model and Wang and Singh model were selected for predicting the drying characteristics of curry leaves. The payback period for the solar dryer was evaluated as 8 months, which is found to be much lower when compared with the entire life span of 15 years. The payback evaluation confirms that the solar dryer is economically viable in rural applications.