Yachao Zeng, Haoran Yu, Jiashun Liang et al.

ECS Meeting Abstracts • 2024

Proton exchange membrane fuel cells (PEMFCs) are a promising zero-emission power source for heavy-duty vehicles (HDVs). However, long-term durability of up to 25,000 h is challenging because current carbon support, catalyst, membrane, and ionomer developed for traditional light-duty vehicles cannot meet the stringent requirement. Therefore, understanding catalyst degradation mechanisms under the HDV condition is crucial for rationally designing highly active and durable platinum group metal (PGM) catalysts for high-performance membrane electrode assemblies (MEAs). Herein, we report a PGM catalyst consisting of platinum nanoparticles with a high content (40 wt %) on atomic-metal-site (e.g., MnN 4 )-rich carbon support. MEAs with the Pt (40 wt %)/Mn–N–C cathode catalyst achieved significantly enhanced performance and durability, generating 1.41 A cm –2 at 0.7 V under HDV conditions (0.25 mg Pt cm –2 and 250 kPa abs pressure) and retaining 1.20 A cm –2 after an extended and accelerated stress test up to 150,000 voltage cycles. Electron microscopy studies indicate that most fine Pt nanoparticles are retained on or/and in the carbon support covered with the ionomer throughout the catalyst layer at the end of life. During the long-term stability test, the observed electrochemical active surface area reduction and performance loss primarily result from Pt depletion in the catalyst layer due to Pt dissolution and redeposition at the interface of the cathode and membrane. The first-principle density functional theory calculations further reveal a support entrapment effect of the Mn–N–C, in which the MnN 4 site can specifically adsorb the Pt atom and further retard the Pt dissolution and migration, therefore enhancing long-term MEA durability.

Shiding Miao, Shulian He, Mengnan Liang et al.

Advanced Materials • 2017

A novel realization of microtubular direct methanol fuel cells ( µ DMFC) with ultrahigh power output is reported by using “rolled‐up” nanotechnology. The microtube (Pt‐RuO 2 ‐RUMT) is prepared by rolling up Ru 2 O layers coated with magnetron‐sputtered Pt nanoparticles (cat‐NPs). The µ DMFC is fabricated by embedding the tube in a fluidic cell. The footprint of per tube is as small as 1.5 × 10 −4 cm 2 . A power density of ≈257 mW cm −2 is obtained, which is three orders of magnitude higher than the present microsized DFMCs. Atomic layer deposition technique is applied to alleviate the methanol crossover as well as improve stability of the tube, sustaining electrolyte flow for days. A laminar flow driven mechanism is proposed, and the kinetics of the fuel oxidation depends on a linear‐diffusion‐controlled process. The electrocatalytic performance on anode and cathode is studied by scanning both sides of the tube wall as an ex situ working electrode, respectively. This prototype µ DFMC is extremely interesting for integration with micro‐ and nanoelectronics systems.

Antsa Salomà El Salam Andriamihaja

International Journal of Innovations in Engineering Research and Technology • 2024

The implementation of massive MIMO technology presents a significant boost in throughput mobile networks. However, this technological advancement comes increases energy consumption. The amalgamation of Massive MIMO with M-MMSE serves as a strategic solution, effectively mitigating energy consumption while delivering substantial throughput and improved Energy Efficiency (EE) compared to alternative techniques. Our study delves into the Energy Efficiency of massive MIMO using the Power Circuit Consumption (PC) model, providing valuable insights into its performance. This analytical approach not only enables a reduction in energy usage but also facilitates a noteworthy enhancement in Spectral efficiency (SE) and EE concurrently. This concurrent improvement addresses the challenge posed by the initial surge in energy consumption associated with massive MIMO deployment, ensuring a sustainable and efficient integration into mobile networks.

M. Falk, D. Pankratov, L. Lindh et al.

Fuel Cells • 2014

Abstract We present data on operation of a miniature membrane‐less, direct electron transfer based enzymatic fuel cell in human sweat and saliva. The enzymatic fuel cell was fabricated following our previous reports on miniature biofuel cells, utilizing gold nanoparticle modified gold microwires with immobilized cellobiose dehydrogenase and bilirubin oxidase. The following average characteristics of miniature glucose/oxygen biodevices operating in human sweat and saliva, respectively, were registered: 580 and 560 mV open‐circuit voltage, 0.26 and 0.1 μW cm –2 power density at a cell voltage of 0.5 V, with up to ten times higher power output at 0.2 V. When saliva collected after meal ingestion was used, roughly a two‐fold increase in power output was obtained, with a further two‐fold increase by addition of 500 μM glucose. Likewise, the power generated in sweat at 0.5 V increased two‐fold by addition of 500 μM glucose.

D. Kaewsai, H. L. Lin, T. L. Yu

Fuel Cells • 2015

Abstract Pyridine‐polybenzimidazole (PyPBI) films of different thickness (∼1.0–2.4 nm) are wrapped on the surfaces of multi‐walled carbon nanotubes (CNTs). To prepare Pt on PyPBI/CNT (Pt‐PyPBI/CNT) catalysts, Pt 4+ ions are immobilized on these PyPBI wrapped CNTs (PyPBI/CNTs) via Lewis acid‐base coordination between Pt 4+ and :N‐ of imidazole groups, followed by reducing Pt 4+ to Pt nanoparticles. The influence of PyPBI film thickness on the Pt particle size, loading and electrochemical surface area, respectively, of Pt‐PyPBI/CNTs is investigated. Fuel cell performances of the PBI/H 3 PO 4 based membrane electrode assemblies (MEAs) prepared from these Pt‐PyPBI/CNT catalysts are also evaluated at 160 °C with unhumidified H 2 /O 2 gases. Among the catalysts, the Pt‐PyPBI/CNT catalyst with a PyPBI film thickness of ∼1.6 nm (which is around half of the Pt particle size), a Pt loading of ∼44 wt.%, and a Pt particle size of ∼3.3 nm exhibits the best fuel cell performance.

Eko Yohanes Setyawan, Awan Uji Krismanto, Mujiono et al.

Journal of Measurements in Engineering • 2024

Water energy is one of the potential renewable energy, the problem so far has a low efficiency of the blade Pelton shape. So it takes a series of tools to know characteristics and performance of the Pelton turbine as a hydroelectric power plant in this research. Pelton turbines work by utilizing the potential energy of water stored at a certain head, which flows through a penstock/pipe that is equipped with a nozzle at the end. The high head causes the water to be under high pressure when it reaches the nozzle. The water coming out of the nozzle becomes kinetic energy in the form of a pressurized water jet, which is used to rotate the runner of the Pelton turbine. In this study, the effect of the number of nozzles used to rotate the Pelton turbine was analyzed, with the result that the number of nozzles is directly proportional to the efficiency of the Pelton turbine. Where the highest efficiency value is obtained by using 3 nozzles with a maximum efficiency value of 13.7 %, at 2 nozzles of 12.209 % and at 1 nozzle of 8.82 %.

Bryan Coyne, Eleanor Denny

Energy Efficiency • 2021

Abstract Ireland’s Climate Action Plan aims upgrade 500,000 homes to B2 Energy Performance Certificate (EPC) standard by 2030. Evidence of an Energy Performance Gap, where actual energy use differs from the EPC, could undermine progress towards such targets. This paper studies the energy performance gap for a general housing sample ( n = 9923) over multiple years. It provides a novel comparison between whole-home energy use (electricity and gas) that accounts for fuel switching and removes potential rebound effects by excluding households that may have changed their behaviour following a retrofit. Results suggest that actual energy use is unresponsive to the EPC, with a range of 457 kWh/year observed across EPC-level averages for the entire sample. This difference equated to less than 5% of the sample average annual energy use observed. The Energy Performance Gap range features an average deficit of 17% below theoretical energy use. The least energy efficient dwellings feature an average difference ranging from − 15 to − 56% of the relevant EPC. Conversely, energy efficient houses display higher-than-theoretical energy use, with average surpluses ranging from 39 to 54% of the relevant EPC. Results sound a note of caution for policymakers that rely on a theoretical EPC to deliver real energy savings. Future EPCs could be improved by incorporating historical household energy usage to help improve models.

Jahangir Afsharian

• 2022

With the fast development of information technology (IT) industry, the demand and market volume for off-line power supplies keep increasing, especially those for telecommunication, computer servers and data centers. As the capital expenditure was measured by the square footage occupied rather than power consumption, the development of high power density converter system is of greater interesting. The rising energy prices have resulted in the cost of power and cooling exceeding the purchase cost in less than two years. Therefore, highly efficient power conversion is required for the power converter system. Generally, the power supply unit (PSU) for power distribution system (PDS) in data center and telecom are the standard two-stage approach which normally consists of power factor correction (PFC) circuit and isolated DC-DC converter. The two-stage power conversion has demonstrated excellent performance and high reliability, since the design can be optimized for each stage. However, limitations to prevent the existing two-stage PSU to fulfill future requirements for the PDS in data center and telecom applications are revealed, and a very promising and fundamentally different approach with the single-stage isolated converter is proposed in this dissertation. The development of single-stage converters with the option of placing the energy storage outside of the PSU creates new degrees of freedom regarding e.g. simplified rectifier racks in telecom and data center. This provides tangible benefits in the form of space saving, better airflow for power unit in rectifier racks and improved lifespan. The three-phase isolated buck matrix-type rectifier, capable of achieving high power density and high efficiency, is identified as an excellent candidate for the medium power level (5 kW~10 kW) single-stage power supply design. Nevertheless, the matrix-type rectifiers are known for their relatively complex modulation and commutation techniques, and lack of ride-through capability such as the stringent case of one phase loss operation. This dissertation work provides comprehensive study on the commutation method and modulation scheme design for the isolated buck matrix-type rectifier. It aims to analyze the operation principle of the rectifier and propose viable modulation and commutation schemes for this rectifier under both three-phase and single-phase operation. The method is verified by the hardware experiments of the PSUs with high efficiency (> 98%) and high power density (> 70 W/in3 ) for 54 V and 380 VDC applications. The prototypes demonstrated in the experiments show the effectiveness of the proposed modulation and commutation schemes for industry.

Marta Zaton, Nicolas Donzel, Sara Cavaliere et al.

ECS Meeting Abstracts • 2023

Adequate material selection is one of the most important aspects in component design. Therefore, high-performance polymers have garnered significant interest for Proton Exchange Membrane Fuel Cell (PEMFC) and Water Electrolysis (WE) applications due to their exceptional mechanical, thermal, and chemical properties. This 'beginning by design' strategy requires a deep knowledge of environmental stressors and degradation mechanisms and focuses on proposing next-generation advanced materials able to withstand defined stress conditions for lightweight and heavy-duty transport applications. This presentation presents recent advances and challenges encountered in the preparation of high-performance polymer-reinforced membranes and highlights their specific properties resulting in exceptional durability of nearly 120,000 cycles when tested under combined Open Circuit Voltage (OCV) with Relative Humidity (RH) cycling. This work was supported by the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 101006641 IMMORTAL. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research.

Shinya Matsunami, Naoki Yamamura, Yuzuru Tsunehiro

Electrical Engineering in Japan • 1995

Abstract An active filter (AF) is a device to eliminate switches. There are two types of AF, the voltage source type and the current source type. The voltage source type is common in practical use today. But we have studied and already reported that the AF of the current‐source type has the characteristics of rapid and precise controllability of the output current and little interference between the AF and the distribution line. In this paper, we propose two schemes to improve its performance and to reduce its capacitance. To improve the performance of AF, we changed the PWM carrier from the triangular wave used in a previous paper to the sawtooth wave. However, the switching rates remain the same. By using the 5 [kHz] sawtooth carrier (corresponding to 2.5 [kHz] triangular wave) and the multiplexed connection of AF, harmonic currents of less than 19‐th order can be eliminated in the distribution line. To reduce the capacitance of the AF, we proposed an AF which eliminates only harmonic currents. By using other apparatus for fundamental reactive power compensation, a more economical system can be achieved. The experimental results on the tested apparatus show that these methods are useful for realization of a current‐source type AF.

Lixian Xue, Na Yang, Yueping Ren et al.

Journal of Chemical Technology & Biotechnology • 2016

Abstract BACKGROUND Graphene has been widely used as an anode modification material to enhance the performance of microbial fuel cells ( MFCs ). The hydrophobicity of graphene and the insulation of the binders used in the electrode preparation were two adverse factors for performance enhancement of the graphene (G) anodes. In this work, binder‐free graphene–cetyltrimethylammonium bromide ( CTAB ) anodes (G‐ CTAB ‐2.5, G‐ CTAB ‐5 and G‐ CTAB ‐10) prepared with low loadings of CTAB treated graphene were fabricated through a simple strategy and their performance tested in single‐chamber MFCs . RESULTS The biofilms on the positively charged and hydrophilic G‐ CTAB anodes had higher electrocatalytic activity and more diverse microbial populations than those on the G anode. The G‐ CTAB ‐5 anode showed the best performance, and the maximum output power density ( P max ) of the MFC was 731.3 mW m −2 which was 3.7 times higher than that of the MFC with the G anode. CONCLUSION The results showed that the G‐ CTAB anode with very low graphene loading exhibited excellent performance. This work provides new prospects for the development of better graphene anodes to further enhance the performance of MFCs . © 2016 Society of Chemical Industry

Q. Yi, H. Chu, M. Tang et al.

Fuel Cells • 2014

Abstract In this paper multi‐walled carbon nanotubes (MWCNTs) supported binary AgNi nanoparticles are prepared by chemical reduction of Ag and Ni precursors with NaBH 4 . Fe/PANI catalyst is obtained by direct pyrolysis of Fe‐doped polyaniline in N 2 atmosphere at high temperature. Results show that the Fe/PANI catalyst presents high electroactivity for oxygen reduction reaction (ORR) in alkaline media. The onset potential for ORR is 0.01 V(vs Hg/HgO) and the ORR current density is 3.4 mA cm −2 @2000rpm at –0.4 V(vs HgO/Hg). A gas diffusion electrode is fabricated by using the Fe/PANI as the electrocatalyst of ORR. In alkaline media the AgNi/MWCNT catalyst displays efficient electroactivity for hydrazine oxidation. A lower onset potential of –0.5 V(vs Hg/HgO) and high current density for hydrazine oxidation are observed. A novel membrane‐less direct hydrazine/air fuel cell is designed by using the AgNi/MWCNT catalyst as the anode and the gas diffusion electrode as the cathode. The as‐fabricated fuel cell works properly and presents higher power density and current density.

, Shivam Srivastava, G. Naga Srinivasulu et al.

International Journal of Emerging Technology and Advanced Engineering • 2024

Proton exchange membrane fuel cell (PEMFC) systems have the ability to meet our energy demands in the near future since they are green, economical, and clean. They can also use hydrogen as a direct fuel. One of the key design factors influencing the PEMFC's performance is flow field configuration. The configuration of the flow channel in a PEMFC has a profound effect on reactant distribution and water management within the fuel cell. Current study aims to ameliorate fuel cell (FC) performance, water management, and pressure drop (PD) across channels. ANSYS Fluent 18.2 software, including its PEMFC add-on module, is utilized to execute a computational fluid dynamics (CFD) simulation of a 3D model of a PEMFC with a flow channel shaped like a honeycomb structure. A polarization curve, as well as factors such as PD, hydrogen and oxygen concentrations, membrane water content, and current density distribution along flow channels, have been included in the simulation results. The findings suggest that when the FC is operated at 0.45V, homogeneous reactant consumption and greater power and current densities are achieved, and, water generation is high across the Membrane Electrode Assembly (MEA).

Jun Yang, Jing Yang, Qing He You et al.

Applied Mechanics and Materials • 2011

A microfluidic cell-electrofusion device was developed for high fusion efficiency and automatic manipulation. It included an experimental platform, an electric signal generator and a microchip. Microstructure and controlling signal were elaborately chosen in order to realize precise cell manipulation, alignment and electrofusion. Compared with the traditional cell-electrofusion device, this device has some outstanding advantages. For example, short distance between two counter-microelectrodes will reduce the required voltage. A large number of microelectrodes can be fabricated on one small chip for high-throughput fusion. Transparent chip architecture benefited for microscopic observation and real-time recording. The integration of the experimental platform, signal generator and microchip is helpful for developing a portable cell-fusion system. On-chip electrofusion experiments of cucumber mesophyll protoplasts have been carried out and up to 40% fusion efficiency was obtained.

Tansu Özel, Stefan Bürger, Carsten Cremers

ECS Meeting Abstracts • 2023

Air pollution is still a bitter truth in many locations in the world. In highly populated regions like metropolitan areas as well as in agricultural areas there are various airborne contaminants which can be harmful to organisms. Also fuel cells, especially PEMFC are sensitive to airborne contaminants. In most mobile and stationary PEM fuel cell systems, ambient air is used as oxidant gas at the cathode of the fuel cell. It is cost and weight saving because there is no need to install additional tank for pure oxygen and to refill it, but the performance of fuel cell can suffer beyond the oxygen gain from airborne contaminants, which also have the potential to accelerate degradation. To prevent that airborne contaminants reach the fuel cell cathode, air filter systems consisting of particle filter and additional activated carbon filter are installed at the cathode inlet. The focus here is on the investigation of the use of AVL THDA tm method to detect effects of airborne contaminants. THDA (total harmonic distortion analysis) is a patented online fuel cell monitoring method based on analyzing harmonic distortion effects of voltage drifts instead of single cell voltage measurement. So far it was successfully demonstrated for the detection of water issues like flooding and drying, and for low media supply issues on both cathode and anode side [1, 2]. For the development and validation of the method, experiments with a PEMFC stack are going to be done on a fuel cell testbed equipped with an AVL X-Ion impedance analyzer. Specific air pollutant gases ammonia (NH 3 ), sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) are going to be mixed into the cathode air in the ppb range. Their effects on PEMFC stack performance are going to be investigated with electrochemical impedance spectroscopy (EIS) and total harmonic distortion analysis. The cathode exhaust gas is also going to be analyzed by an FTIR gas analyzer. It is planned to test the PEMFC stack under different operating conditions, with various parameters and different cathode gas mix ratios while monitoring possible conversion of impurities via FTIR and the stack state of health using THDA and conventional technologies to understand the link between the effect of airborne contaminants on fuel cell stack performance, on its lifetime and to determine possible early indicators in the THDA signals. References [1] Mitzel, J., Sanchez‐Monreal, J., Garcia‐Sanchez, D., Gazdzicki, P., Schulze, M., Häußler, F., Hunger, J., Schlumberger, G., Janicka, E., Mielniczek, M., and Gawel, L. 2020. Fault Diagnostics in PEMFC Stacks by Evaluation of Local Performance and Cell Impedance Analysis. Fuel Cells 20, 4, 403–412. [2] Ramschak, E., Peinecke, V., Prenninger, P., Schaffer, T., and Hacker, V. 2006. Detection of fuel cell critical status by stack voltage analysis. Journal of Power Sources 157, 2, 837–840.

Martha Stando, Arnaud Morin, Gerard Gebel et al.

ECS Meeting Abstracts • 2023

With climate change and fossil fuel sustainability concerns faced globally, proton exchange membrane fuel cell (PEMFC) based electric vehicles have been recognized as a promising alternative. However, large-scale commercialization requires progress in performance, cost and durability, for which the electrode (catalyst layer) is the limiting component. The electrode is composed of nanoparticles of platinum (Pt) catalyst on a carbon (C) support, embedded in a proton conductive polymer (ionomer). It is obtained from a slurry (catalyst ink) after evaporating solvent consisting of a water and alcohol mixture. The structural properties of the slurry, including the ionomer and carbon dispersions, catalyst aggregation and ionomer coverage onto the Pt/C composite strongly influence the performance and durability of the final electrode. Nevertheless, currently little is known of these structures, particularly with regards to the dispersion of the ionomer component onto the surface of porous carbon, despite the fact it is now established that it plays a crucial role in the operation of the fuel cell. The lack of information leaves research and development to be heavily reliant on a trial and error basis. Developing a detailed understanding of the dispersion and its correlation to fuel cell performance is key in advancing the PEMFC electrode. However, the heterogeneous nature of these inks, with only short-range order observed on both micro- and nano- scales, makes them difficult to study by conventional laboratory techniques. Small angle neutron scattering (SANS) has been identified as a suitable method for the study of the electrodes as it is not hindered by the ink opacity as in optical techniques (commonly used to study dispersions) and allows to probe the bulk structures in the 1-100 nm scale relevant for each component. In particular, contrast variation (CV) SANS exhibits a major advantage in studying such complex systems, where scattering signal from multiple components can be deconvoluted by matching the scattering length density of the solvent to that of a desired component. Nevertheless, data on the ink itself is missing and it has only been investigated in a handful of studies by SANS. 1-3 Shibayama et al. 1 proposed a structural model of Pt/C aggregates coated by an ionomer shell in a water-based ink. Yoshimune et al. 2 demonstrated that the amount of Pt on the carbon surface alters the thickness and density of said ionomer layer. Harada et al. 3 were able to distinguish adsorbed and deposited ionomer on the composite surface as well as quantize their distribution. Yet although ink composition is known to impact the dispersion greatly, no systematic investigation linking its many variables has been conducted. For example, the ionomer will conform differently in a water/alcohol solvent used commercially in contrast to a water-based one. The porosity of the carbon support will impact distribution of Pt on its surface as well as the degree of ionomer penetration into the support. Additionally, although the fundamental understanding of the ink structure is imperative, it has seldom been further linked to the performance of the electrode itself. Therefore, the aim of this project is to utilize CV-SANS to study the impact of each catalyst ink component on the structure of the dispersion, and their relation to each other, through altering only a single variable at a time. The variables include the components as well as their proportions, such as the carbon concentration or the ionomer to carbon ratio. The performance of the electrode manufactured from said ink compositions will then be evaluated using electrochemical studies. Recently we performed CV-SANS studies on the ink, investigating the extent of ionomer adsorption on the Pt/C composite as a function of both carbon type and presence of Pt in the system. Both carbon supports studied, high surface area carbon with surface nano-pores accessible to the ionomer, and graphitized carbon, which has high internal porosity, yet inaccessible to the ionomer, pose an interest in industrial applications. Indeed, from these preliminary results it is evident platinum plays a significant role in the ink structure, particularly in the case of graphitized carbon (figure 1). The ink system will be quantitatively characterized using a singular value decomposition method already employed in literature to give insight into parameters such as the amount of ionomer adsorbed onto the carbon surface or the structure of the layer. References 1 M. Shibayama, T. Matsunaga, T. Kusano, K. Amemiya, N. Kobayashi and T. Yoshida, J Appl Polym Sci , , DOI:10.1002/app.39842. 2 W. Yoshimune and M. Harada, https://doi.org/10.1246/cl.190017 , 2019, 48 , 487–490. 3 M. Harada, S. I. Takata, H. Iwase, S. Kajiya, H. Kadoura and T. Kanaya, ACS Omega , 2021, 6 , 15257–15263. Figure 1

Nilesh Jaiswal, Vivek Pratap Singh, Dolly Kumari et al.

Energy Technology • 2023

The goal of bifacial technology is to increase the efficiency of solar cells (SC) by capturing albedo sunlight and converting it to electrical energy. The use of triple‐cation mixed‐halide perovskite solar cells (PSC) has sparked a lot of curiosity and could be the potential for improved power conversion efficiency (PCE) associated with traditional PSCs. Herein, n– i –p‐configured triple‐cation mixed‐halide‐based bifacial PSC is studied using the SC capacitance simulator 1D tool. Through our simulation, the impact of thickness in electron and hole transport layers (ETL and HTLs), defect density, doping density, and the thickness of the light‐harvesting layer on the device performance is examined. With an optimal design, the device exhibits an absolutely staggering efficiency of 25.28% from the front side and around 17.19% from the rear. This cell, due to its high albedo absorption, linearly enhances the short‐circuit current; hence, it overcomes the classical current‐matching limit of ordinary PSCs. The proposed device FTO/TiO 2 /[Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 ]/CuSbS 2 has a remarkable efficiency that increases linearly with albedo, making it very appealing for new, high‐efficiency solar applications.

Mohammad Ali Shafii, Elsa Yolanda Putri, Feriska Handayani et al.

Journal of Physics: Conference Series • 2021

Abstract Study of neutronic performance analysis of Sodium-Cooled Fast Reactor (SFR) design based on the variations of output power using radial fuel suffling strategy has been performed. SFR is a type of the generation IV reactor that is widely researched for application on a commercial scale. The reactor design uses natural uranium as a fuel and Sodium as a coolant. The research has been carried out by using the SRAC code and JENDL-3.2 as a library with two dimensional R - Z suffling strategy of cylinder core for variations of power output 300, 350, 400, 450 and 500 MWTh. The neutronic parameters such as a multiplication factor ( k -eff and k -inf) and burn-up analysis are observed. The SFR core is separated into 10 regions having the same volume fraction in the radial direction. At beginning of burn-up process, the reactor core is only filled with natural uranium fuel called fresh fuel and prepared for the one cycle of 10 years of burn-up time. The burn-up result in the first region is shifted into the second region, the burn-up result in the second region is shifted into the third region, and so on until burn-up result into the tenth region. The burn-up result in the tenth region is removed from the reactor core, then the first region can be filled with fresh natural uranium fuel and so on up to 10 times fuel cycles of reactor operation. The neutron calculation results indicate that the multiplication factors ( k -eff and k -inf) in a critical condition are occurred on the 300 MWTh of output power. Overall, the output power of 300 MWTh has requirements and a greater chance of being operated for SFR designed.

Graham Mensa-Wilmot, Stephen G. Southland, Patrick Andrew Mays et al.

All Days • 2009

Abstract Drilling programs continue to be pushed into harder and more abrasive formations. In addition, directional drilling activities, with the on-going surge in deployment, have become more complex. Well depths, profiles, dog-leg severity (DLS), departures, and the other associated parameters, are continuously been pushed into newer and more challenging frontiers. Consequently, and as a result of these factors, sharp operational cost increases are being recorded. The resulting economic impact challenges the practicality of the industry's push for oil and gas in harsher environments. Considering the undeniable need to find new oil and gas reserves, the cost increases must be reversed. Performance drilling, when effectively implemented, will serve as one of the enablers that facilitate achievement of this objective. This paper will define and establish the framework for performance drilling (PD). In addition to identifying performance qualifiers (PQ), it will also establish their dependencies and relationships. The significance of offsets, especially in the benchmarking process will also be discussed. Drilling efficiency1,2 will be analyzed and differentiated from rate of penetration (ROP) maximization3. Value creation, measured in terms of drilling cost reductions per section drilled, will also be discussed. Performance data, supporting the discussions and processes outlined in this paper, will be presented. Background The need to improve drilling performance, as an operational cost reduction initiative, is seen as a critical industry goal. Researchers and engineers, to better understand the requirements that influence this objective, have committed time and resources to this endeavor. As a result, new drilling tools, technologies4,5, and processes are continuously being developed to support this effort. Although project objectives have always been obvious, results have sometimes fallen short of expectations. In some instances, and even when the intended performance effects are achieved, the results have not been sustainable. PD, to achieve its intended benefits, must sustain and continuously improve on past results. To achieve this goal, the industry needs to have an open discussion that focuses on PD and its constituents. As a starter, PD needs a definition. Currently, there is ambiguity as to what it means. Some in the industry believe that the use of a new tool or technology constitutes PD. In this regard, there is the assumption that what is new or claimed to be new technology is always better. Some also believe that the use of drive tools that increase RPM or torque (PDM or turbine) in a bottomhole assembly (BHA) qualifies as PD. Others associate PD with the use of rotary steerable tools (RST). It must be stated, that even when relevant for a particular drilling operation, the mere use of a new technology or tool does not qualify as PD. The current ambiguity in PD's definition has created a process vacuum. As an enabler to reductions in operational cost, it is not enough to just identify the need for PD. This realization must be supported by processes that help identify and optimize the factors that influence PD.

V. Boscaino, G. Capponi

Advances in Power Electronics • 2012

Wide-input, low-voltage, and high-current applications are addressed. A single-ended isolated topology which improves the power efficiency, reduces both switching and conduction losses, and heavily lowers the system cost is presented. During each switching cycle, the transformer core reset is provided. The traditional tradeoff between the maximum allowable duty-cycle and the reset voltage is avoided and the off-voltage of active switches is clamped to the input voltage. Therefore, the system cost is heavily reduced and the converter is well suited for wide-input applications. Zero-voltage switching is achieved for active switches, and the power efficiency is greatly improved. In the output mesh, an inductor is included making the converter suitable for high-current, low-voltage applications. Since the active clamp forward converter is the closest competitor of the proposed converter, a comparison is provided as well. In this paper, the steady-state and small-signal analysis of the proposed converter is presented. Design examples are provided for further applications. Simulation and experimental results are shown to validate the great advantages brought by the proposed topology.

Bhaskar P. Saripella, Umit O. Koylu, Ming C. Leu

ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology • 2015

Flow field design in Proton Exchange Membrane (PEM) fuel cells is a major area of research for performance improvement. Bio-inspired flow field designs are a relatively recent development in fuel cell technology evolution. These novel designs have potential for performance improvements by effective distribution of reactant gases with better water management capabilities. This work investigates the performance and water distribution in a bio-inspired flow field design, formulated using Murray’s law and mimicking a typical leaf venation pattern, in comparison to a conventional single serpentine design. Experiments were conducted using a transparent fuel cell with copper as the conductive channel and current collector. The results indicated the superior performance of the bio-inspired design with a 30% increase in peak power density in comparison to the single serpentine design. Additionally, the flow regimes based on two-phase flows in micro channels were identified and their effects on fuel cell stability were determined.

Shangwei Zhou, Lara Rasha, Linlin Xu et al.

ECS Meeting Abstracts • 2023

It is well known that reasonable current density distribution can improve fuel cells' output performance and prolong their service life. Which can be achieved by elaborately designed structures and compression, and the reaction occurs evenly in the entire activation area. However, duo the coupling relationships between electrical, thermal and water, the effect of operation conditions (such as the local heating) on the current density mapping is still blank. This paper studies the effect of local heating on polymer electrolyte fuel cell performance and analyses the causes of the output voltage differences through the mapping of the current density distribution. Compared with the inlet and central heating, the heating at the outlet area exhibits the best performance. This is due to the concentration of reactants along the flow field decreases continuously, and the accumulation of liquid water leads to the low current density distribution at the outlet. Here, we show that local heating can compensate for the lowest current density and achieve the more homogeneous current distribution; on the contrary, inlet heating will increase the unevenness of the current density distribution. This study provides practical guidance for the optimal design of the thermal management system.The design of the cooling channel should be locally optimised for more uniform distribution of current density, in addition to the overall temperature balance,

S. Matsumoto, K. Yamanaka, H. Ogikubo et al.

Applied Physics Letters • 2014

Microbial fuel cells (MFCs) are promising devices for capturing biomass energy. Although they have recently attracted considerable attention, their power densities are too low for practical use. Increasing their electrode surface area is a key factor for improving the performance of MFC. Carbon nanotubes (CNTs), which have excellent electrical conductivity and extremely high specific surface area, are promising materials for electrodes. However, CNTs are insoluble in aqueous solution because of their strong intertube van der Waals interactions, which make practical use of CNTs difficult. In this study, we revealed that CNTs have a strong interaction with Saccharomyces cerevisiae cells. CNTs attach to the cells and are dispersed in a mixture of water and S. cerevisiae, forming a three-dimensional CNT conductive network. Compared with a conventional two-dimensional electrode, such as carbon paper, the three-dimensional conductive network has a much larger surface area. By applying this conductive network to MFCs as an anode electrode, power density is increased to 176 μW/cm2, which is approximately 25-fold higher than that in the case without CNTs addition. Maximum current density is also increased to approximately 8-fold higher. These results suggest that three-dimensional CNT conductive network contributes to improve the performance of MFC by increasing surface area.

Farid Breidi, Tyler Helmus, Michael Holland et al.

ASME/BATH 2014 Symposium on Fluid Power and Motion Control • 2014

High speed valves have an important role in many existing fluid power systems and are an enabler for many proposed digital hydraulic systems. One method commonly used to improve the dynamic performance of on-off valves involves modifying the electrical input signal to the solenoids to reduce the inductive lag and eddy current decay. This research examined two commercially available direct actuated and pilot-stage actuated cartridge poppet valves and the role of peak-and-hold voltage and reverse current input profiles on opening and closing switching times. A test stand was built to characterize the performance of these valves. The valves were placed between two high frequency pressure transducers and the pressure differential across the valves was recorded, allowing the calculation of transition and delay time. The peak and reverse voltage duration was tested over a range of zero to ten milliseconds and an optimum response was found at a peak duration of six to eight milliseconds. Peak voltages ranged from 50 to 55 volts, followed by a holding voltage of 12 volts. Reverse current profiles were used to turn off the valves with a maximum peak current of three amps. The reverse current was used to increase the decay rate of eddy currents thus improving the turning off performance of the valves. Commercial valves that had a range of 33 to 55 millisecond turn-on response without input signal modification; these same valves had response times reduced to a range of seven to nine milliseconds after applying the peak and hold method. The turn-off time was reduced from 130 milliseconds to a range of 16 to 50 milliseconds after adding reverse current inputs. This improvement in valve performance can lead to siginificant energy savings due to reduction of transition losses and can widen the useful application of the valves.

Alejandra Rosales‐Sierra, Sergio Rosales‐Mendoza, Elizabeth Monreal‐Escalante et al.

ChemistrySelect • 2017

Abstract The start‐up of microbial fuel cells (MFCs) requires biofilm development onto electrodes and acclimation of the microbial community to specific substrates. This process is time‐consuming and shows low effectivity when complex substrates are utilized. The varying proportions and complex mixtures of volatile fatty acids (VFAs) in bioprocess effluents makes it difficult to predict the power output of VFA‐based MFCs when this technology is coupled to a previous bioprocess. In this work, the effect of the degree of reduction of single VFAs on MFC potential was investigated, and a novel acclimation procedure involving the feeding of gradually more complex VFA mixtures is proposed. The power output obtained with butyric acid (6.1 ± 2 mW m −2 ) was higher than that obtained with propionic acid (5.0 ± 1 mW m −2 ), as expected based on their degree of reduction. The MFC potential generated by an acetic acid‐fed MFC reached 60 mV, but an acetic‐butyric acid mixture reduced the cell potential by one order of magnitude. The subsequent addition of propionic acid to the acetic‐butyric mixture increased the MFC potential from 1.9 ± 0.1 mV to 35 ± 10 mV in sequential feeding cycles. Consequently, the feeding sequence of acetic, acetic‐butyric, and acetic‐butyric‐propionic acids is proposed as an efficient strategy for the acclimation of MFCs to complex substrates.

Eduardo D Penteado, Carmen M Fernandez‐Marchante, Marcelo Zaiat et al.

Journal of Chemical Technology & Biotechnology • 2015

Abstract BACKGROUND Microbial fuel cells ( MFCs ) can treat agro‐industrial wastewater, but only a few studies have reported the treatment of winery waste and much work is needed in order to develop this interesting application of MFC technology, in particular in evaluating how the unfavorable COD /N and COD /P ratios may affect the MFC performance. In this work, a dual chamber MFC was used to treat real effluents from wine processing factories. RESULTS The MFC was not efficient in terms of COD removal, even when nutrients concentration was increased and daily removals which oscillated around 1000 mg L ‐1 d ‐1 were observed during the complete experimental period, with COD removals around 17%. Increases in the phosphorus and nitrogen concentrations positively influenced the production of electricity. By increasing the concentration of phosphorus and nitrogen, Coulombic efficiency was increased from 2% to almost 15%, and maximum power density from 105 to 465 mW m ‐2 . CONCLUSIONS Results demonstrate that electricity can be produced efficiently and that the unbalanced nutrients/ COD ratio is a major challenge in the treatment of winery wastewater, in spite of the very high organic load contained in this type of wastewater. © 2015 Society of Chemical Industry

Fuel Cells Bulletin • 2018

UK-based Ceres Power unveiled a new 5 kW stack platform and the latest progress in its SteelCell ® V5 at the recent FC Expo 2018 in Japan. The 5 kW intermediate-temperature solid oxide fuel cell (IT-SOFC) stack platform offers increased power density, reduced startup times, and vibration tolerance, with the potential to address automotive applications, while the latest SteelCell V5 test results show significant advances in efficiency, and lower degradation.

Zeyu Du, Ming Liu, Junjie Yan

ASME 2024 Power Conference • 2024

Abstract The world energy supply continues to evolve and adapt to low carbon and sustainable sources due to energy shortage and environmental issues. As a result, the share of renewable energy sources in the energy mix sharply increases in many countries. However, wind and photovoltaic power is intermittent, and high penetration of renewable power poses high peak shaving pressure on the power system. Therefore, the peak shaving techniques for coal-fired power plant (CFPP) should be developed, aiming to decrease the adjustable minimal power load ratio. When the coal-fired power plant operates under low load ratio, it significantly deviates from the design condition, which will affect the operational safety and economic performances. In this study, the drainage obstruction issues of the feedwater preheating system are analyzed and addressed. Off-design analysis models of coal-fired power plant are developed. Simulation results show that the feedwater preheating system increases the net energy efficiency by 2.90%, 3.11%, 2.49% under 100%, 30% and 20% power load ratio conditions, respectively. The pressure difference between adjacent regenerative heaters (RH) decreases with the load ratio, thus increasing the risk of the drainage obstruction phenomenon. Then, schemes, including the RH’s switch-off, connecting the drainage pipe to deaerator (DRTR) or condenser, or installing the drainage pump (DP) in the drainage pipe are proposed and evaluated. Scheme A connects RH2’s and RH3’s drainage pipes to the DRTR, which can improve the unit’s operational stability and energy efficiency greatly when the drainage obstruction occurs in high-pressure feedwater preheating system. Scheme B connects RH7s and RH8’s drainage pipes to the condenser and Scheme C installs DPs in RH7s and RH8’s drainage pipelines. Scheme B and Scheme C can both enhance the operational stability of low-pressure feedwater preheating system under low load ratio condition. Scheme C have better energy efficiency performance than scheme B, but with more retrofit expense on the pump purchases. Results of this study can provide some guidance for the safe operation of the feedwater preheating system.

Chien‐Ming Wang, Chang‐Hua Lin, Shih‐Yung Hsu et al.

IET Power Electronics • 2014

A novel interleaved boost dc/dc converter with zero‐current‐switching pulse‐width‐modulation (ZCS‐PWM) characteristic using a simple ZCS‐PWM auxiliary circuit is presented in this paper. The proposed converter combines the conventional PWM technique and ZCS technique to promote the circuit performance. The proposed converter uses dual boost converters which are operated at interleaved mode to increase the output power level. Thus, the proposed converter does not only decreases the current stress on main circuit devices but reduces the input ripple current and output capacitor size. Because the proposed converter establishes a common ZCS‐PWM auxiliary circuit on used dual boost converters, it can greatly reduce the size and cost. And, it can provide the ZCS characteristic on main switches and auxiliary switches with a wide range of load to improve the problem of switching losses and EMI. Thus, its topology is simple and compact. Besides operating at constant frequency and reducing commutation losses, the proposed converter has no additional current stress and conduction loss in the main switch compared with the conventional interleaved boost dc/dc converter. The principle of operation, theoretical analysis and experimental results of the proposed boost converter, rated 1 kW and operating at 40 kHz, are provided in this paper to verify the performance of this new family of converters.

Hao Ren, Yunping Niu

AIP Advances • 2022

Wireless power transfer (WPT), which transfers energy without a physical link, has recently received significant research interest. Due to the advantages of small dimension, low operation frequency, and low transmission loss, magnetoelectric WPT (ME-WPT) has been shown to be a promising technology for internet of things (IoT) and implantable medical device (IMD) applications. However, ME-WPT requires a direct-current (DC) magnetic bias for optimal performance and prior arts have implemented large electromagnets, Helmholtz coils, or externally positioned magnet bias systems, which increase the system dimension. Furthermore, the highest energy conversion efficiency (ECE) reported by prior ME-WPT studies is 0.62%, which needs to be improved. In this paper, we present an ME-WPT system with a novel miniaturized ME-WPT receiver and a spiral coil based transmitter. Four DC magnets are integrated onto the ME-WPT receiver to significantly reduce its dimension while providing a DC magnetic bias of 190 Oe for optimal performance. Electrochemical polarization characterizations are introduced to analyze the performance of the WPT receiver, which reveal that a maximum output power of 4.096 mW is obtained. A record ECE of 2.64% is reported, the highest among all ME-WPTs to date. The output power is improved by at least 49.3 times compared with the ME-WPT without integrated DC magnets. The influence of the input voltage and the distance between transmitter/receiver on the performance of the ME-WPT system is studied, which shows that the output power increases as the distance decreases and the input voltage increases. The proposed ME-WPT system with integrated DC magnets has potential applications in IoT and IMDs.

Hui Meng, Yunfeng Zhan, Dongrong Zeng et al.

Small • 2015

This work reports a detailed investigation of the template‐free synthesis of Pt nanowires via the chemical reduction of Pt salt precursors with formic‐acid. The results indicate that both the oxidation state of Pt in the salt and the pH value of the aqueous solution comprising the platinum salt and formic acid are critical factors for the formation of Pt nanowires. Nanowires are obtained from platinum atoms in a +IV oxidation state, with ligating chloride anions (H 2 PtCl 6 and K 2 PtCl 6 ) or nonligating chloride anions (PtCl 4 ). Increasing the pH of the aqueous Pt salt and HCOOH solution leads to a drastic reduction of the nanowires' length between pH 3 and 4.5. A mechanism involving formate as a reducing agent and formic acid as a structure directing agent explains these results. The Pt nanowires are stable up to 200 °C; therefore, these nanowires are suitable for use as catalysts in proton‐exchange‐membrane fuel cell. The optimized synthesis conditions are then selected for investigating the kinetics of the oxygen reduction reaction (ORR) of such nanowires in a fuel cell. The ORR mass activity of the Pt nanowires is 130 A g −1 Pt at 0.9 V iR‐free potential; significantly higher than that of two commercial Pt/C catalysts tested in the same conditions. The higher mass activity is explained based on a higher surface specific activity. Accelerated degradation tests indicate that Pt nanowires supported on carbon are as stable as Pt nanoparticles supported on carbon.

Qi Liu, Biao Xiong, Yuxuan Liu et al.

International Journal of Automotive Manufacturing and Materials • 2024

Article Study on Performance Simulation Matching of One-Dimensional Hydrogen Storage and Supply System for Hydrogen Fuel Cell Vehicles Qi Liu 1,2, * , Biao Xiong 1,3, Yuxuan Liu 1,3, Chuanyu Zhang 1,3, Shuo Yuan 1,2, and Wenshang Ma 1,3 1 College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China 2 Research Institute of Hunan University in Chongqing, Chongqing 401120, China 3 State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China * Correspondence: author: hnuliuqi@hnu.edu.cn Received: 1 July 2024; Accepted: 12 September 2024; Published: 27 September 2024 Abstract: With the improvement of environmental protection requirements, hydrogen fuel cell vehicles are considered one of the most potential and promising new energy vehicles because of their advantages, such as pollution-free emission, long cruising range, and short hydrogenation time. However, there are still unresolved problems between the storage and supply of hydrogen and the power demand during the operation of hydrogen fuel cell vehicles. In this study, a hydrogen fuel cell vehicle is taken as the research object, and a one-dimensional model is built according to the basic performance parameters so as to explore the operation law of the power performance demand of the hydrogen fuel cell vehicle, simulate the power demand in the actual operation process, summarize the influence of different parameters on the power economic performance of the vehicle, and put forward optimization strategies to improve the power, durability, and fuel economy of the vehicle.

Lei Niu, Li Xiao

Intelligent Marine Technology and Systems • 2024

Abstract Current research on energy management strategies (EMSs) often neglects the impact of system topology and local control. This study tackles this issue by optimizing the topology of the hybrid power system on the ’FCS Alsterwasser’ cruise ship and enhancing EMS performance using various local controllers. First, the paper outlines the objectives of the research and provides an analysis of the current domestic and international research status. Second, the methods used in this study are introduced, including the topology optimization method and EMS. Subsequently, a model of the hybrid power system is constructed and verified through simulations. Finally, the effectiveness of different strategies is evaluated according to simulation results. Compared with an EMS based solely on a proportional-integral controller, the combination of a state machine and droop controller achieves better results, reducing battery power fluctuations by 86.5% and fuel cell power fluctuations by 16.2%.

G. Squadrito, O. Barbera, G. Giacoppo et al.

Journal of Fuel Cell Science and Technology • 2006

Fuel cell technology development is one of the main activities at CNR-TAE Institute. Particular attention was devoted to polymer electrolyte fuel cells (PEFCs), which are the most probable candidates as future energy suppliers for transportation and for portable and domestic applications. The research activity was addressed to new materials and component evolution, system design, and modeling. Because a single cell is not able to supply the desired voltages also for small electronic devices, a PEFC stack of different sizes must be evolved to match the application request. The research activity focused on two different areas: small size stacks for portable applications and medium power stacks (1–4kW) for transport and stationary applications. This activity was supported by modeling and computational fluid dynamic studies, and by the evolution of dedicated test station and measurement devices. The first result of PEFC stack research was the development of a 100W stack prototype working at low pressure and based on low Pt loading electrodes evolved at CNR-ITAE. Starting from this experience, a hydrogen fueled air breathing stack of 15W for portable application was realized. The scale up of the cell active area was approached by searching for a method to allow the design of the flow field with specified geometrical characteristics and fluid dynamic properties to maintain the performance reached in small active area cells. A computer-aided design method was evolved, and the design of the 200cm2 active area cell was realized, starting, from a 50cm2 laboratory cell.

Flavio Colmati, Ruy Sousa, Eduardo Gonçalves Ciapina et al.

ECS Meeting Abstracts • 2014

A previous workon Pt-Sn/C catalysts for ethanol oxidation (1) showed that a thermal treatment at moderate temperatures leads to a significant increase in activity. The best activity was observed for Pt 3 Sn 1 thermally treated at 200 o C and ascribed to the formation of a Pt 3 Sn 1 phase, plus a cleaning effect of the thermal treatment. However, it is well known that electronic effects may be as important as geometric effects in bimetallic catalysts, and these were not evaluated in the Pt 3 Sn 1 phase. Obtaining information on the electronic structure, particularly in the electrochemical environment is of importance. Pt-Sn catalysts were synthesized by reduction of suitable precursors with formic acid following procedures already described (2). The composition of the catalysts was determined by EDX using a Zeiss Digital Scanning Microscope, with a micro analyzer Link Analytical QX 2000. High resolution diffractograms were obtained using Synchrotron radiation at the Brazilian Synchrotron Light Laboratory (LNLS). The electronic properties of the catalysts were probed by x-Ray absorption spectroscopy in the XANES region performed at the LNLS. All measurements were performed with the electrode containing the catalysts polarized at 300 mV vs. RHE. Gas diffusion fuel cell electrodes were built with two layers, a diffusion layer and a catalytic layer prepared as already described (1). The MEAS were prepared as described previously (3). The EDX results show that the actual concentrations of the catalysts are very near the nominal values. The results in direct ethanol fuel cells (DEFC) show that the performance with as prepared Pt 3 Sn 1 catalysts was much poorer than with Pt 3 Sn 1 (E-TEK). The lattice parameter of both catalysts show that the E-TEK material is almost 100% alloy, and the difference in performance was attributed to this fact. In order to increase the degree of alloy of the as-prepared catalyst different portions were submitted to thermal treatment at different temperatures. Results showed that a thermal treatment at 200 o C did not alter the main properties of the catalyst, but higher temperatures led to the formation of agglomerates. As a consequence of this the results in DEFC showed that the as prepared catalyst treated at 200 o C showed better performance than the E-TEK catalyst. The degree of alloy in the thermally treated catalyst increased from 14 to 22% but it is still lower than in the E-TEK catalyst. The conclusion is that a good Pt-Sn catalyst requires a suitable degree of alloy between Pt an Sn and also the presence of non-alloyed Sn, which is probably in the form of oxide, that promotes the bifunctional effect. Figure 1 presents the XAS results, mainly in the XANES region, for the as prepared and thermally treated Pt 3 Sn 1 catalysts, and also for a Pt foil used as reference. The analysis of white lines presented in Fig. 1 was performed using Shukla´s method (4) as described in detail in a previous work (4). Figure 2 shows the fitted Lorentzian functions from which the integrated intensities were calculated: 529 for Pt foil, 553 for as prepared Pt 3 Sn 1 and 523 for thermally treated Pt 3 Sn 1 , in arbitrary units. From these results it may be concluded that by increasing the degree of alloy of Sn and Pt the vacancies of the 5d band of Pt, responsible for the adsorption of poisons are reduced. Acknowledgements To FAPESP, CNPq and CAPES, Brazil for financial support. To the Brazilian Synchrotron Light Laboratory for assisting with the DRX and XAS experiments. References F. Colmati, E. Antolini, E.R. Gonzalez, ECS Trans., 3 , 1307 (2006). E. G. Ciapina, E. A. Carbonio, F. Colmati, E. R. Gonzalez, J. Power Sources, 175 , 18, (2008). F. Colmati, E. Antolini, E. R. Gonzalez, J. Alloys and Compounds, 456 ,264 (2008). R. Souza Jr, F. Colmati, E.G. Ciapina, E.R. Gonzalez, J. Solid State Electrochem., 11 , 1549 ( 2007

Kunbo Cao, Yong Xu, Wandi Lu et al.

Research Square • 2024

Abstract In this paper, a SMIC 0.18µm BCD process low-dropout regulator (LDO) with high power efficiency, high power supply rejection (PSR) and fast-transient response is proposed for power management modules in RF energy harvesting systems. A buffer and pole-zero tracking structure are added to achieve only one dominate pole in the unit gain bandwidth (UGB). Simulation results show that the maximum power efficiency of LDO achieves 96.1% and it consumes 18µA quiescent current, delivering a load current range from 0-30mA over a 10µF load. The overshoot voltage is 0.14% of output voltage and the recovery time is less than 3.2µs when the load is varied from no-load to full-load, and the PSR is better than − 47dB at 1MHz.

Farhan Mumtaz, Nor Zaihar Yahaya, Sheikh Tanzim Meraj et al.

Sustainability • 2023

Fuel cells have drawn a lot of interest in recent years as one of the most promising alternative green power sources in microgrid systems. The operating conditions and the integrated components greatly impact the quality of the fuel cell’s voltage. Energy management techniques are required in this regard to regulate the fuel cell’s power in a microgrid. The active/reactive power in the microgrid should be adjusted in line with US Energy Star’s regulations whereas the grid current needs to follow the standard set by IEEE 519 2014 to enhance the power quality of the electrical energy injected into the microgrid. Uncontrolled energy injection from the fuel cell can have serious impacts including superfluous energy demand, overloading, and power losses, especially in high power and medium voltage systems. Although fuel cells have many advantages, they cannot yet produce high voltages individually to compensate for the demand of a microgrid system. Due to these reasons, the fuel cell must be interfaced with a DC-DC converter. This research proposes a novel high voltage gain converter integrated 1.26 kW fuel cell for microgrid power management that can boost the fuel cell’s voltage up to 20 times. Due to this high voltage gain, the voltage and current ripple of the fuel cell is also reduced substantially. According to the analysis, the proposed converter demonstrated optimal performance when compared to the other converters due to its high voltage gain and extremely low voltage ripple. As a result, the harmonic profile of the microgrid current persists with a reduced THD of 3.22% and a very low voltage ripple of 4 V. To validate the converter’s performance, along with extensive simulation, a hardware prototype was also built. The voltage of the fuel cell is regulated using a simplified proportional integral controller. The operating principle of the converter integrated fuel cell along with its application in microgrid power management is demonstrated. A comparative analysis is also shown to verify how the proposed converter is improving the system’s performance when compared against other converters.

Mostafa Salah, Menna Elkomy, Omar Mohamed et al.

WSEAS TRANSACTIONS ON POWER SYSTEMS • 2025

A solar cell is an electrical device that converts light energy into electrical energy via the photovoltaic effect. Sometimes called a photovoltaic cell or PV cell. In essence, a solar cell is a p-n junction diode. Solar cells are a type of photoelectric cell, which is characterized as an apparatus that changes its electrical properties in response to light, including resistance, voltage, and current. Organic-inorganic halide-based perovskite solar systems are getting closer to commercialization and have become more efficient. Because lead-based perovskite materials have toxicity issues, the scientific community has recently become interested in lead-free alternatives. A lead-free n-i-p based planar heterostructure perovskite solar cell made of intrinsic-CH3NH3SnI3 methyl ammonium tin iodide (MASnI3) as an i- and p-layer Spiro-OMeTAD with SnO2 for the n layer is optimized for device efficiency using SCAPS numerical simulation. The 3rd layer (electron layer) is modified with an efficiency of 2.03%, with another material SnO2, as the efficiency increased to 2.62%, Voc of 0.6428V, Jsc = 6.44 mA/cm2, and FF of 63.40% are achieved. After that the cell layers of the cell are optimized to achieve the highest efficiency of 10.13%.

Ana L. G. Biancolli, Edson Antonio Ticianelli, Valdecir Antonio Paganin et al.

ECS Meeting Abstracts • 2016

The catalytic dehydrogenation of ethanol on a Cu / ZrO 2 catalyst at 250 ° C has been recently proposed as a suitable approach for the production of CO-free hydrogen[1]. In this way, the hydrogen-rich gas stream generated in this system had been directed to the anode of a PEM fuel cell, that presented 70% of the efficiency obtained when pure hydrogen was used. The reason for this considerable loss in performance was not clear and this is the main motivation of this work. For this investigation, we have used a system in which hydrogen was contaminated with the by-products of the ethanol dehydrogenation reaction, which were unreacted ethanol, acetaldehyde and ethyl acetate. The influence of these last substances on the performance of the PEMFC was studied through various techniques, including electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, cell polarization response, high performance liquid chromatography (HPLC) and mass spectrometry. The results had confirmed that the impurities coming from the ethanol dehydrogenation reactor are the responsible for the loss of the fuel cell efficiency. Polarization curves showed that the presence of unreacted ethanol in the system is the main cause of this effect, wherein the acetaldehyde and ethyl acetate have smaller contribution. Studies involving online mass spectrometry indicated that there is no formation of CO or CO 2 as by-products, as detected in the anode outlet of the cell. Analysis of the liquid effluent of the anode by HPLC, at several cell potentials ranging from 900 to 100 mV, revealed the presence of acetic acid as oxidation product on the PEM fuel cell electrode, with contents particularly high at the higher cell potentials (closer to 900mV). These studies showed that ethanol is the major contaminant of the electrode, either when directly administrated to the cell, or when it is formed by degradation of other contaminants at the PEMFC anode. Electrochemical impedance spectroscopy was utilized to evaluate the influence of the above-mentioned contaminants on the oxygen reduction reaction, since occurrence of their crossover from the anode to the cathode of the MEA was detected. The influence of each contaminant in the PEMFC performance was analysed in operando at low overpotentials (low currents - 72 mA to 500 mA). It can be inferred that at high potentials, the losses in the PEMFC performance is due to the poisoning of the oxygen electrode, when both anode and cathode catalyst were Pt/C 30 wt.%. From these data, it is shown that the proton transport resistance (membrane and cathode catalyst layer) and electrical contacts are not affected by the contaminants at these potentials. Studies on the increase of the Pt load on the anode, as well on the replacement of the Pt/C catalyst on the cathode by bimetallic Pt-based catalysts, such as PtCo and PtCr, proved ways to minimize the effects of the contaminants on the oxygen cathode. [1] A. G. Sato, G. C. D., Silva, V. A. Paganin, E. A. Ticianelli. ECS Transactions , 64 (2014)999-1005.

Mugachintala Dilip Kumar, D. Himabindu, Yarrem Narasimhulu Vijaya Kumar et al.

International Journal of Applied Power Engineering (IJAPE) • 2024

Accessing the unelectrified rural population is currently not possible through grid expansion, as connectivity is neither economically viable nor encouraged by large companies. Additionally, conventional energy options, such as broom-based systems, are being gradually phased out of rural development programs because to growing oil prices and the unbearable effects of this energy source on consumers and the environment. A hybrid generator using solar and wind can solve this issue. Proven hybrid systems are the best choice for delivering high-quality power. Nowadays, hybrid renewable energy systems are becoming popular. The power system provides electricity to remote and isolated areas. Villages and residents in the forest area had their electricity cut off due to the forest environment. While creating a renewable energy source near the load. Solar power and wind power are renewable sources, solar power works in the morning and wind can make morning and night time to synchronize both output voltage and frequency to provide provides the ability to charge continuously, without interruption. The main objective of the project is to provide mixed renewable energy without interruption.