Exergetic and techno‐economic analysis of Moroccan horehound leaves (Marrubium vulgare L.) in forced convection solar and microwave drying

AbstractThis paper aims to analyze solar and microwave drying of Horehound leaves (Marrubium vulgare) from an exergetic point of view. Solar drying tests in forced convection were performed at airflow rates (150 and 300 m3/h) and air‐drying temperatures (60°C, 70°C, and 80°C), where the microwave tests were performed in microwave powers ranging from 50 to 450 kW. Four performance parameters were investigated: exergy of evaporation, exergy loss, and exergy efficiency, sustainability index, and the improvement potential rate of the drying chamber and drying process. The results show that the exergy efficiency increases with the increase of aerothermal conditions. Exegetic performances essentially depend on the drying air temperatures and the airflow rates. The exergy efficiency of the drying process is higher than that of the drying chamber. The drying characteristics of Horehound leaves treated under microwave irradiation is a crucial process to predict its moisture content design so as to optimize the drying process. The exergetic analysis presented in this manuscript shows an improvement in the sustainability index of the drying processes and the reducing losses due to the irreversibility of large‐scale production of dry plants by using solar dryer systems. The techno‐economic analysis performed on the solar dryer including the calculation of the cost of production of 1 kg of dried product shows the economic profitability of drying this kind of product using the convective solar dryer.