Comparative Study of Performance of Indirect Mode with PCM and Mixed Mode Solar Dryer for Coriander Leaves

摘要

Solar energy can be utilised in many useful ways and solar assisted drying is one of them. In this present study, a natural convection indirect mode solar dryer with phase change material (PCM) and mixed mode solar dryer were designed, fabricated and experimentally investigated. These systems consist of one solar collector and one drying chamber with two trays and in addition PCM cavity was made in collector in indirect mode solar dryer. In this study, thin layer drying characteristics of Coriandrum Sativum L. leaves is studied. 200 grams of Coriander leaves were dried from initial moisture content of 88.02% to 9.68% of final moisture content in 3 hours and 3 hours 15 minute in case of indirect mode with PCM and mixed mode solar dryer respectively during month of February in Gorakhpur (India). The experimental data is validated with fourteen thin layer models available in either empirical or non-empirical form. A statistical analysis software XL-Stat is used to evaluate the values of constants of models through non-linear regression analysis. Among all the models available for thin layer drying characteristics logarithmic, Wang and Singh, Midilli et al., Two term and modified Henderson and pabis (5 models) are best fitted the drying behaviour of Coriander leaves for indirect mode with PCM and Midilli et al. model is best suitable to describe the thin layer characteristics of coriander leaves by mixed mode solar dryer. The thermodynamic behaviour of indirect mode solar dryer is also evaluated. The indirect mode with PCM and mixed mode solar dryer have maximum efficiency of 10.99% and 9.69% whereas overall collector efficiency was 73.19% and 70.79% respectively.