Session: 09-02 Solar Desalination

Paper Number: 117023

117023 - Numerical Heat and Mass Transfer Modeling and Techno-Economic Analysis of Metallic Porous Structures for Passive Pumping in Solar-Thermal Desalination Systems. 

Water scarcity is a growing challenge worldwide, resulting from increased population growth, industrial practices, and shifting climates. Researchers have been studying reliable, efficient, and cost effective techniques to obtain high quality fresh water using a renewable and clean energy source.  Deployable, solar-thermal desalination systems are promising technologies for promoting water security and sustainable community development in remote or storm-damaged coastal regions. Current solar desalination systems rely on a significant portion of the energy created from the photovoltaic array to fuel the desalination process. However, the very problem that leads to inefficiencies in current solar desalination systems has the potential to drive the efficiency of a new type of solar desalination system. The introduction of novel, metallic wicks in these systems would increase distillate efficiency by generating an evaporation interface. It is proposed that metallic wicks with optimized micro-structure porous properties will further increase distillate yields in capillary-driven desalination modules. Recent studies have demonstrated the potential of metallic wicks for increased distillate production at low-temperature (< 50 °C) operation.  Many other studies assessed the quality of the distilled water, but they did not evaluate the salt accumulated at the water-vapor interface within the wick resulting from the evaporation.  Another important issue that impacts the passive flow resulting from the wicking action is the dry-out that might occur within the metallic wick in the porous medium due to the evaporation process. A two-dimensional, finite volume numerical heat and mass transfer study was performed to investigate the impact of variable microstructure properties and environmental conditions on the distillate yield, wick dry-out, and salt diffusion/precipitation within candidate porous media structures. The metallic wick was assumed to remain fully saturated during modeled conditions. A parametric study was constructed using a face-centered central composite designs to optimize wick microstructure properties including averaged porosity (2.5 µm – 10 µm pore size) wick material (Ni, Cu, SS304), and bi-porous ratio (0 to 0.75) for specific environmental conditions of surface temperature (30 °C to 100 °C) and module pressure (> 100 mbar). Salt diffusion was also modeled to identify operating conditions where salt crystallization would lead to restrictions in pore size and wick clogging or salt concentration limitations of brine resources. An initial techno-economic analysis was performed to evaluate the financial feasibility and economic impact of a passive wick-based desalination system attached to photovoltaic panels. The wick-based desalination modules were proposed to provide passive cooling of the photovoltaic field, improving photovoltaic performance while simultaneously producing fresh water. The levelized cost of energy and levelized cost of water were calculated using a systems-level heat and mass transfer analysis and compared to existing solar still technologies.

Presenting Author: Abdullah Alfarhan University of Dayton

Presenting Author Biography: Abdullah Alfarhan is a mechanical engineering student seeking a Ph.D. at University of Dayton. His area of research is Thermos-Fluid/Renewable energy applications that directly help to serve, develop, and support communities’ essential needs. His current research is modeling and designing of porous metallic structures for passive pumping in solar-thermal desalination systems. He has experience in gas/oil production as he worked in a gas plant operation, sulfur recovery unit dealing with various kinds of valves, pumps, and vessels. He also has experience in well drilling/cementing as he worked in the field, testing cementing mixture and then pumping it into wells. Abdullah has earned a B.S degree in mechanical engineering from University of Texas at San Antonio, and M.S. degree from University of Dayton.