Experimental optimization of conical solar distillers using graphite pin fins as sensible heat storage materials: Energy, exergy, and exergo-economic approach

Fresh water and energy are essential for the development and prosperity of societies. Solar stills are easy to build, operate, and maintain, but their disadvantage is low daily productivity. This work aims to optimize and enhance the performance of conical solar stills by integrating innovative graphite pin fins that function as extended surfaces and sensible energy storage in the distillation basin. Graphite is inexpensive, available locally, natural properties, and has good thermal characteristics and heat capacity. Four different alternates spacing between the graphite pin fins ranging from 10 to 70 mm have been investigated and optimized to achieve maximum daily water production. Three identical conical solar distillers were designed, manufactured, and tested, under the same weather conditions in El Oued city, Algeria (33.3676 degrees N and 6.8516 degrees E). Energy, economy, exergy, and exergo-economics approach were performed to evaluate the economic feasibility of modified conical distillers. The results showed that reducing the distance between the pin fins leads to a decrease in the productivity of the distiller due to the increase in the shadow area. Among the pin fin distances evaluated, the 50 mm distance achieved the highest daily water production with reasonable economic feasibility. Adding graphite pin fins to conical distiller basin increases daily productivity and thermal efficiency by 52.16-90.78% and 33.44-63%, respectively. The production cost and payback time of the modified conical distillers with pin fins are reduced by 35.49-79.72% and 35.48-79.72%, respectively compared to the traditional conical stiller.