Design and Testing of a Solar Greenhouse Dryer for Marigold Flower Seed Extraction

This study presents the design, development, and testing of a solar greenhouse dryer specifically for drying marigold flowers. Traditional methods being adopted for drying marigold are labour-intensive and time-consuming. The newly developed solar dryer, equipped with evacuated tube solar air heaters, significantly reduces drying time to about 2 days with a higher seed germination rate of 90%. Experimental trials established 50°C as the ideal drying temperature for seed viability. Analysis for environmental impact revealed significant CO₂ mitigation with an energy payback period of 7.57 years and earning lifetime carbon credits worth Rs. 65,794.40. Economic feasibility of the system revealed a payback period of 2.86 years. Additionally, it enabled early sowing of crops such as watermelon and melon, enhancing farm profitability. The solar dryer represents an efficient, environmentally sustainable, and economically viable option for farmers, with a potential for wide adaptation of marigold seed production.