Optimal Design of Porous Media in Solar Vapor Generators by Carbon Fiber Bundles

As a means of harvesting solar energy for water treatment, solar-driven vapor generation is becoming more appealing. Due to their entangled fibrous networks and high surface area, fibers can be used as building blocks to generate water vapor. In this paper, using a two-dimensional fiber bundle model, we studied the generation of solar vapor based on the fiber height, distance between fibers, and input sun radiation. The performance of solar absorption system was also evaluated by evaluating thermal and water management. Results showed a constant increase in solar vapor generation with an increasing fiber height and decreasing inter-fiber distance. However, the gain rate of using taller and more densely packed fiber bundles dwindled quickly. On the other hand, a shorter fiber had a higher evaporation rate per fiber height. The distance between fibers had a nonlinear effect on the fiber bundle evaporation rate. A new fiber bundle design was recommended with a fiber height of 15–20 mm and an inter-fiber distance of 1.5 mm. The results of this study can provide guidelines for future fiber bundle designs with increased efficiency, reduced cost, and versatile applications (i.e., desalination, water purification, and power generation).