Optimization and experimental study on the effect of graphite bars on the productivity of conical solar distiller: Exergo-economic approach

This work aims to enhance productivity and reduce the production cost of conical solar distillers using green and inexpensive materials. Conical solar stills are characterized by their cover is always exposed to the same solar radiation in all locations and do not create shading. Different graphite bars are installed at various distances in the still basin, acting as corrugated surfaces and energy storage materials to increase the interface area, reduce energy losses, and enhance the overall performance. Three conical stills were designed and tested to investigate the effect of changing the distances (0 to 30 mm) between the graphite rods on the production rate at the same climatic conditions of El Oued, Algeria. Furthermore, energy, exergy, economic, and exergoeconomic approaches were conducted to assess the viability of the proposed distillers. Results showed that reducing the distances between graphite bars increases the production rate due to the increased interfacial space with basin water and the storage of excess heat absorbed during the day. The energy and exergy efficiencies of the proposed conical solar distillers incorporated with graphite bars improved by 46.23-90.46 % and 181-321 % respectively, compared with the traditional conical still. Based on the exergo-economic approach, the annual energy and exergy outlets improved by 45.65-90.46 % and 187.5-439 % respectively, compared to the traditional conical still. The cost of the yield and payback period decreased by 40.41-74.91 % and 28.8-42.8 % respectively, compared to the traditional conical still. Finally, incorporated graphite rods with conical solar stills represent a good option for obtaining high performance with economic benefit.