Simulating the Power Output of Large Bifacial Photovoltaic Plants

Bifacial photovoltaic modules have gained increasing attention in the last decade due to their potential to achieve higher annual energy yield in comparison to conventional monofacial modules. Since the higher energy production is also accompanied by higher investment costs, it is necessary to conduct a careful techno-economic analysis in order to provide the investors an answer about their accurate cost efficiency. The achievable energy output of a bifacial photovoltaic power plant is influenced by many factors such as module geometry, row spacing, orientation of the modules and ground albedo. Since the methodology for prediction of the energy yield has not yet been standardized, the main target of this paper was to create one version of a comprehensive standalone energy calculator that would serve as a useful performance assessment tool for designers and investors. The developed software tool was tested on several characteristic scenarios and the obtained results were compared with the results provided by two freely available online calculators.

Shell and lumen side flow and pressure communication during permeation and filtration in a multibore polymer membrane module

This study reveals the importance of the module geometry on the flow field and pressure distribution during membrane permeation for multibore membranes. The pathways of permeation are unraveled within a custom-made multibore single membrane module. For this, we combine flow velocimetry of magnetic resonance imaging (flow-MRI) with computational fluid dynamic (CFD) simulations and permeation experiments. First, a systematic simulation study identifies flow patterns based on simplified geometrical features that are supported experimentally through flow-MRI measurements. This comprehensive study shows how small geometric deviations from the idealistic assumptions result in unexpected fluid flow on the shell and lumen side in the module. Second, the influence of those non-ideal flow patterns during the filtration of silica particles are revealed by MRI. The results indicate heterogeneous silica deposition due to geometry induced flow fields. Contrary to the idealized assumption, the subsequent backwashing is also influenced by those deposition patterns. Hence, unavoidable non-idealities of membrane positioning during the construction of the module influence the performance of the membrane filtration. With this study, we stimulate to analyze and pioneer new strategies to optimize module design and fully recover the membrane's performance after filtration cycles during backwashing. Even more, extensive future studies on multiple multibore membranes can reveal their mutual interaction closing the gap between the single multibore membrane behavior and multibore membrane module properties.

The Effect of Module Geometry on Heat and Mass Transfer in Membrane Distillation

Some features of Direct Contact Membrane Distillation (DCMD), as one of the interesting membrane processes, has been studied in this effort. 3D computational fluid dynamic simulations were carried out to investigate some geometric parameter effects on flat sheet membrane module performance. It is obvious that using of baffles could noticeably improve the performance of the system. Hence, in present work, some baffle configurations were simulated and some parameters like temperature polarization, vapor flux and pressure drop through module length were investigated. The Simulation was performed based on neglecting viscous flow in membrane pores and dusty gas model was applied to predict vapor flux through membrane. Simulation results predicted that by using the new configuration we could have 40–60% vapor flux improvement (depend on inflow velocity) compared to a module without baffle. It was found that the average temperature polarization (TP), as a proper criteria, was higher for baffled one in all situations.

Mass transfer examination in electrodialysis using limiting current measurements

The impact of electrodialysis module characteristics on mass transfer was examined using the limiting current method. The current-voltage curves of different electrodialysis modules were measured and limiting currents were determined using the derivative method. The mass transfer coefficients were calculated and the parameters of their dependence on linear flow velocity were estimated. From these the impact of spacer thickness, spacer net type, membrane type, and module geometry were evaluated. It was found that the impact of spacer thickness was almost negligible within the examined range, but a decrease in the mass transfer coefficient could be expected in the case of thicker spacers. By contrast, the spacer net type and type of membrane were found to be very important parameters able to significantly influence the mass transfer. By modifying the module geometry, the mass transfer coefficient could also be altered and, only in this case, the exponential parameter of the dependence was changing. The parameters thus determined may be used to calculate the limiting current in a wide range of operational conditions and may help predict the performance of different electrodialysis module types