The main objective of the current work is to study the drying behaviour of herbs and to determine the techno-economic analysis of a developed solar dryer. For this purpose, the herbs like amaranthus, mint, and moringa are selected for this study.  The initial moisture of amaranthus (88% w.b), mint (90% w.b), and moringa leaves (80% w.b) was reduced to a final desired moisture content of 7.3, 9, and 4% (w.b), respectively. 15 kg products were loaded in the dryer during experimentation drying is faster in forced convection mode compared to natural convection and open sun. A detailed economic analysis was conducted through three techniques. As stated in annualized cost technique, the cost of drying in an electric dryer is far higher than the solar dryer. The life cycle savings method for the solar dryer with 20 years life span was obtained around 17.98 to 35.89 INR (Lakhs), and the payback period is assessed as 1.6, 1.9, and 0.9 years, which indicates the respective products are broadly lower than the estimated lifetime of the solar drying system. Hence, it was proven that capital investment made on the solar dryer can be recovered even in the initial years of the operation, which shows its financial viability.

Solar irradiance for the 4 days was collected using the pyranometer and some parameters like ambient temperature, chamber temperature, absorper plate temperature, etc., were collected using the PT 100 sensor which is connected to the digital data logger.