Rated Output Power Research Articles

A Novel Hydrogen Production System Based On Multistage Reverse Electrodialysis

Salinity gradient energy can be converted into hydrogen energy through the system combining multi-stage reverse electrodialysis (MSRED) with polymer electrolyte membrane water electrolysis. However, the relevant performance of the system has never been investigated. In this paper, the influence of relevant parameters of MSRED on the performance of the system was analyzed theoretically through a reliable mathematical model. The results showed that increasing the flow velocity of solutions will cause remarkable decrease in the energy recovery of the system, although the total output power and hydrogen production rate of the system increase correspondingly. Besides, thickening compartments of the high concentration solution is effective to reduce the energy consumption for pump with a small augment in the total output power and hydrogen production rate of the system, while the energy recovery of the system is still dropping slowly.

Multi-criteria study and machine learning optimization of a novel heat integration for combined electricity, heat, and hydrogen production: Application of biogas-fueled S-Graz plant and biogas steam reforming

The current research introduces an environmentally friendly heat design method by employing biogas fuel, aiming to yield electricity, hydrogen, and heating load simultaneously. The proposed arrangement consists of a biogas-powered S-Graz plant and a biogas steam reforming cycle. Although methane-fueled S-Graz plants for multigeneration purposes have been studied in previous studies, research on employing biogas fuel to launch a S-Graz plant and integrating a biogas steam reforming cycle with such a plant has yet to be examined. The model is simulated using the engineering equation solver software, and the study includes thermodynamic, exergoeconomic, and sustainability assessments to show the potential of the suggested configuration. By conducting a sensitivity study, a machine learning optimization method within MATLAB is implemented to exhibit the final optimal solution for the proposed arrangement. This optimization uses artificial neural networks and a non-dominated sorting genetic algorithm-II algorithm in a triple-objective framework based on energy efficiency, sustainability index, and products’ specific cost. The optimization demonstrates that the mentioned objectives reach optimal values of 58.26 %, 4.56, and 15.56 $/GJ, respectively. Also, the optimal net output power and hydrogen production rate equal 5746 kW and 1.45 m3/s, respectively. Besides, the process determines the optimal exergy efficiency, total net present value, and payback period as 52.70 %, 50.3 M$, and 8.96 years, respectively. The total investment cost rate for this system also is found to be 219.8 $/h.

A micro-channel cooling system with two-phase looped thermosyphon for a supercritical CO2 Brayton cycle

The supercritical Carbon Dioxide (sCO2) closed Brayton cycle is a promising power generation technology, while the efficient cooling of CO2 and precise control of Compressor Inlet Temperature (CIT) is crucial for the high cycle efficiency and stable compressor operation due to the acute variation of thermophysical properties in the near-critical region. In conventional indirect cooling scheme, an intermediate single-phase water circuit is used to transfer heat from CO2 to water at the precooler, and then from water to the environment at the cooling tower, having the disadvantage of large pumping work consumption and high thermal resistance. In this work, a self-driven two-phase looped thermosyphon that significantly enhances the heat transfer by internal evaporation and condensation, is proposed to replace the water circuit. An experimental ultra-compact cooling system, consisting of a looped thermosyphon combined with micro-channel evaporator and condenser, filled with R134a coolant, is designed, fabricated, and tested. Visualized observation of the two-phase flow pattern and simultaneous measurement of the temperature, pressure and mass flow rates are conducted. A nodal analysis method is adopted, and a MATLAB code is developed for analyzing the internal fluid flow and the coupled sCO2-R134a-Air heat transfer, which is validated by experiment data. The results show that, the CO2 temperature could be accurately maintained at a specified near-critical point with a fluctuation of less than 1 K, and the average heat-releasing temperature can be reduced, while considerable pumping work, usually accounting for 2–5 % of the rated power output can be saved, thus contributing to increased cycle efficiency and system compactness.

Development of integrated packaged single fuel cell short stack based on titanium metal plates for mobile power generation

Bipolar plates (BPPs) and membrane electrode assemblies (MEAs) are the key components for proton exchange membrane fuel cells (PEMFCs), they are alternately arranged to construct a compact stack with high power generation. This stacking method may introduce several issues, such as the difficulties in maintenance, imprecise assembly and sealing. This paper presents a novel integrated packaged single fuel cell that employs titanium metal bipolar plates to construct a short stack with superior sealing performance and working reliability. To predict the performance of integrated packaged single cell, numerical model was developed to analyze the mass transfer of O2, H2 and H2O within the cell, revealing a uniform distribution of reactants and current. A short stack was manufactured with 10 layers of single cells, it retains excellent sealing properties and consistent output across a range of pressure conditions, with a leakage rate deviation lower than 0.03 mL/(min·cell) and membrane current density variation less than 5%. Finally, the electrochemical performance of the integrated packaged short stack was tested, its maximum power is 886.67 mW/cm2. It can achieve a rated output power of 169.14 W and an energy density of 1684.97 mW/cm3. Thus, our developed short stack has high energy utilization efficiency for power generation, and is anticipated to provide a durable power source for drones, robots and new energy vehicles.

Comprehensive assessment of voltage and current source PV‐based modular multilevel converters

AbstractRecently, modular multilevel converters (MMCs) gained popularity for the grid integration of photovoltaic (PV), due to their many advantages, including low total harmonic distortion, high control flexibility, and distributed maximum power point (MPP) tracking capability. Two distinguished families of MMCs exist: voltage source and current source. Voltage source MMCs are mostly studied, but current source MMCs offer advantages under certain operating conditions. This article compares voltage and current source MMCs, for PV integration. To this aim, several key indicators are identified: number of components, energy stored in passive elements, semiconductor power rating, and the number of MPP trackers. The results of the analysis, performed in MATLAB©, show that for a fixed number of output voltage levels, power rating, and switching frequency, voltage source MMCs have simpler control and higher number of MPP trackers. In contrast, current source MMCs minimize the semiconductor power rating, the number of components and the energy stored in passive elements. Regarding efficiency, in the analyzed case study, voltage source MMCs perform better under both homogeneous and non‐homogenous irradiance conditions. This article provides a tool to select the optimal solution based on the required target (e.g. efficiency, energy storage etc.), given the specific characteristics of the application.

Enhanced Coil Design for Inductive Power-Transfer-Based Power Supply in Medium-Voltage Direct Current Sensors

This paper presents an integrated coil design method for inductive power-transfer (IPT) systems. Because a medium-voltage direct current (MVDC) distribution network transmits power at relatively high voltages (typically in the tens of kV), accurate fault diagnosis using high-performance sensors is crucial to improve the safety of MVDC distribution networks. With the increasing power consumption of high-performance sensors, conventional power supplies using optical converters with 5 W-class output characteristics face limitations in achieving the rated output power. Therefore, this paper proposes a safe and reliable power supply method using the principle of IPT to securely maintain the insulation distance between the distribution network and the current sensor-supply line. A 100 W prototype IPT system is investigated, and its feasibility is validated by comparing its performance with conventional optical converters.

Enhancing concentrated photovoltaic power generation efficiency and stability through liquid air energy storage and cooling utilization

Amid escalating climate concerns, particularly global warming, there is a significant shift towards renewable energy sources. Concentrated Photovoltaics (CPV) are at the forefront of this transition due to their high efficiency and clean energy generation capabilities. However, CPV cell stability and reliability are compromised by high operating temperatures, necessitating effective cooling solutions. This study proposes a novel coupled Concentrated Photovoltaic System (CPVS) and Liquid Air Energy Storage (LAES) to enhance CPV power generation efficiency and mitigate the challenges of high cell temperatures and grid integration. The research introduces an innovative process employing the cell liquefaction cycle for LAES, utilizing surplus cooling capacity to maintain CPV cells at optimal temperatures. A comprehensive thermodynamic analysis optimizes the coupled system’s operation and evaluates its economic benefits. The integrated system improves generation efficiency and economic viability of CPVS, resulting in a 24.41 % increase in photovoltaic module efficiency and a 2.03 % increase in overall rated power output. This leads to a 56.59 % increase in annual revenue for a 50 MW CPVS. Importantly, the findings demonstrate that integrating LAES with CPVS not only enhances solar energy utilization and economic benefits but also significantly contributes to the sustainability of clean, low-carbon energy systems, inspiring a greener future.

Comparative performance and emission analysis of internal combustion engine and battery electric vehicle under modified Indian drive cycle

This study deals with an analysis of the performance and emissions characteristics of an automotive Compression Ignition Engine Vehicle (CIEV) with 86 kW rated power output fueled with diesel in comparison to a grid based Battery Electric Vehicle (BEV) with 86 kW Electric Motor under the Modified Indian Drive Cycle (MIDC) using the simulation. A novel methodology for undertaking the comparative analysis is developed to assess the CIEV and BEV performance for different scenarios under wide operating conditions. The results indicate that energy consumptions for CIEV and BEV under the MIDC cycle are 2653.1 kJ/km and 416.72 kJ/km. The net effective carbon price during fuel production and vehicle operation is Rs 0.20 per km for CIEV which is 80 % more than Rs 0.11 per km for BEV. A BEV also has an initial carbon debt due to battery production which is 27 times that of CIEV, however, this penalty is easily recovered within a short period against the lower running costs of BEV. The range of the ICE power source is estimated to be 5.85 times that of the EV for MIDC. By increasing the battery capacity five fold, the range of EV can be enhanced, however considerable weight penalty is levied. The levelised cost of transportation for one lakh kilometers was assessed wherein it was found that ICE vehicle expenditure is approximately Rs 25.59 per km against Rs 23.31 per km of BEV.

Energy loss analysis in two-stage turbine of compressed air energy storage system: Effect of varying partial admission ratio and inlet pressure

The compressed air energy storage (CAES) system experiences decreasing air storage pressure during energy release process. To ensure system stability, maintaining a specific pressure difference between air storage and turbine inlet is necessary. Hence, adopting a judicious air distribution scheme for the turbine is crucial. Partial admission, based on reasoned nozzle governing methods, enhances system performance. This investigation explores the impact of varying partial admission ratio (PAR) and inlet pressure on flow dynamics and loss characteristics under rated output power. Full circumferential numerical simulations of a two-stage axial turbine within CAES system elucidates insights. First-stage efficiency declines linearly with decreasing PAR, while second-stage displays escalating reductions. Principally, turbine energy losses primarily stem from the entropy production rate (EPR) by turbulent dissipation and EPR arising from heat transfer with fluctuating temperature gradients. Partial admission significantly affects losses within the rotor, especially within the second stage. Leaving velocity loss for 50 % PAR is about 3 times that of 100 % PAR. The percentage of losses within R2 for 50 % PAR increases by 6.7 % compared with that for 100 % PAR. This research provides theoretical insights for designing, regulating, and optimizing nozzle governing and partial admission turbines in CAES systems.

Full load optimization of a hydrogen fuelled industrial engine

There are a large number of applications in which hydrogen internal combustion engines represent a sensible alternative to battery electric propulsion systems and to fuel cell electric propulsion systems. The main advantages of combustion engines are their high degree of robustness and low manufacturing costs. No critical raw materials are required for production and there are highly developed production plants worldwide. A CO2-free operation is possible when using hydrogen as a fuel. The formation of nitrogen oxides during hydrogen combustion in the engine can be effectively mitigated by a lean-burn combustion process. However, achieving low NOx raw emissions conflicts with achieving high power yields. In this work, a series industrial diesel engine was converted for hydrogen operation and comprehensive engine tests were carried out. Various measures to improve the trade-off between NOx emissions and performance were investigated and evaluated. The rated power output and the maximum torque of the series diesel engine could be exceeded while maintaining an indicated specific NOx emission of 1 g/kWh along the entire full load curve. In the low-end-torque range, however, the gap to the full load curve of the series diesel engine could not be fully closed with the hardware used.

Flight verification of cooling self-sustaining high-temperature superconducting motor

The global shift towards sustainable development and technological advancements has propelled the energy transition trend. Recognizing the substantial environmental impact of conventional commercial airplanes, there is a growing urgency to develop a sophisticated superconducting motor system for commercial aviation. The advent of high-temperature superconducting motors presents a transformative leap, offering significant advantages in power density and efficiency when compared to traditional motors. To validate the issues that future liquid-hydrogen superconducting electric airplanes may encounter, a kilowatt-class aerospace high-temperature superconducting motor is designed. Based on the requirements of airborne applications, critical parameters such as electromagnetic characteristics, operating characteristics, and AC losses have been analyzed. Furthermore, extensive research and testing have been conducted on the superconducting motor magnet, leading to the successful assembly of a prototype. The superconducting motor has a rated output power of 2.7 kW and a rated speed of 5000 rpm. Rigorous ground operation performance tests have also been conducted to ensure the feasibility and reliability of the motor in practical applications. Benefiting from the topological structure design, the superconducting motor has an excellent sealing performance at low temperatures. The superconducting motor can maintain low temperature and high vacuum for a long time, when the vacuum pump is removed and the liquid nitrogen inlet is closed after the motor is completely cooled. The culmination of these endeavors is the realization of a successful flight validation of an unmanned aerial vehicle equipped with a high-temperature superconducting motor, demonstrating a sustained flight of nearly one hour.

Thermo-economic analysis of organic Rankine cycle using a new two-stage solar collector with nanofluids

The flat plate collector (FPC) has a low economic cost, while the parabolic trough collector (PTC) has a high heat collection temperature. To reduce costs, improve efficiency, and promote the use of solar energy, this study proposes a new two-stage solar collector that couples FPC and PTC. The main objective of this paper is to verify the performance of this two-stage solar collector when containing nanofluids. This collector drives the organic Rankine cycle (ORC) with four nanoparticles (Cu, CuO, TiO2, and Al2O3) in the oil heat transfer fluid. The FPC outlet temperature in the two-stage solar collector is optimized, the exergy of ORC is analyzed, and the economics of the new system using nanofluid are calculated and compared with those of the new system without nanofluid. Results show that Cu-oil outperforms the other nanofluids in terms of heat transfer. At a rated output power of 5 kW, the new two-stage solar collector with 5 % Cu-oil can reduce economic costs by 6.8 % compared with a single PTC. Meanwhile, the ORC with a two-stage solar collector using 5 % Cu-oil reduces the economic costs by 5.7 % compared with the ORC equipped with PTC without nanofluid. The new system has a minimum payback period of 17.3 years, and increasing the output power of the ORC is beneficial for reducing the investment payback period of the system.

Performance optimization of an integrated solar combined cycle for the cogeneration of electricity and fresh water

Many Arabic countries suffer water scarcity while having an energy surplus. The present work investigates and optimizes a proposed plant for the cogeneration of electricity and fresh water. This plant comprises an Integrated Solar Combined Cycle (ISCC) power plant and a Multi Stage Flash (MSF) desalination unit. The steam condenser of the ISCC acts as a brine heater of the MSF desalination unit. Thus, the waste thermal energy from the ISCC is used to desalinate the seawater. The proposed cycle produces fresh water during its part load operating conditions. Simulation programs were developed and validated using real data from the ISCC power plant in Kuraymat-Egypt. The present results show that the proposed plant is very promising for the cogeneration of electricity and fresh water. An optimum top brine temperature (To) of 80 °C was estimated based on the amount of fuel required to desalinate the seawater. The proposed plant produces up to 1140 m3/h of fresh water under the typical operating conditions of Hurghada-Egypt, 50 % of the rated output power, and To = 80 °C. It saves up to 84.7 % of the fuel required for desalination compared to a standalone MSF desalination unit that operates under the same conditions.

Performance Rating and Flow Analysis of an Experimental Airborne Drag-Type VAWT Employing Rotating Mesh

This paper presents the results of a performance analysis conducted on an experimental airborne vertical axis wind turbine (VAWT), specifically focusing on the MAGENN Air Rotor System (MARS) project. During its development phase, the company claimed that MARS could generate a power output of 100 kW under wind velocities of 12 m/s. However, no further information or numerical models supporting this claim were found in the literature. Extending our prior conference work, the main objective of our study is to assess the accuracy of the stated rated power output and to develop a comprehensive numerical model to analyze the airflow dynamics around this unique airborne rotor configuration. The innovative design of the solid model, resembling yacht sails, was developed using images in the related web pages and literature, announcing the power coefficient (Cp) as 0.21. In this study, results cover 12 m/s wind and flat terrain wind velocities (3, 5, 6, and 9 m/s) with varying rotational velocities. Through meticulous calculations for the atypical blade design, optimal rotational velocities and an expected Tip Speed Ratio (TSR) of around 1.0 were determined. Introducing the Centroid Speed Ratio (CSR), which is the ratio of the sail blade centroid and the superficial wind velocities for varied wind speeds, the findings indicate an average power generation potential of 90 kW at 1.4 rad/s for 12 m/s and approximately 16 kW at a 300 m altitude for a 6 m/s wind velocity.

Design of a broadband high‐efficiency extended resistive continuous Class‐B/J power amplifier with novel drain voltage waveforms

AbstractThis article presents an extended resistive continuous broadband Class‐B/J (ERCB/J) power amplifier (PA) that incorporates two newly designed parameters in the drain voltage waveform. The incorporation of these newly designed parameters enables the PA to achieve a lower degradation rate of efficiency and output power over a wide bandwidth. To validate the effectiveness of the proposed method, a PA was designed, fabricated, and measured. The PA adopting commercially available GaN high electron mobility transistor technology operates from 1.0 to 3.0 GHz, exhibiting a fractional bandwidth of 100%. Across this frequency range, the PA delivers more than 39.6 dBm of saturated output power and more than 62% of drain efficiency. The measured results show good agreement with theoretical analysis and simulation, confirming the validity of the proposed method.

Design and Analysis of Automated Solar Panel Cleaning System

The primary focus of this study was the development of a solar panel cleaning machine intended for the maintenance of photovoltaic solar panels after their installation. The study also encompassed detailed analysis of this machine. The accumulation of dust particles on solar panels presents a significant challenge, as it jeopardizes the optimal functionality of these panels. By obstructing crucial sunlight, dust diminishes the panels' electricity production capacity, consequently reducing overall efficiency. Moreover, this dust accumulation poses a threat to the integral electrical components of the panels, potentially causing harm to the embedded silicon wafers through overheating if left unaddressed. This situation escalates the necessity for post-installation maintenance and escalates associated repair costs. In response to these challenges, a novel automated mechanism for cleaning solar panels is introduced in this paper, effectively eliminating dust particles. The analytical findings strongly indicate that consistent and periodic cleaning of panels can uphold a stable rate of electricity generation within the power production system. This innovative system design empowers users to effortlessly operate the machine in less time, all the while delivering superior cleaning performance when compared to conventional manual methods. To establish a competitive edge in the market, it is imperative that the proposed system presents a cost-effective solution, evaluated in relation to the number of panels cleaned. Consequently, for the purpose of testing the proposed system, a solar installation was meticulously designed and implemented at PDEA’s College of Engineering in Manjari, (Bk.) Pune, Maharashtra, India. This location was deliberately selected as the experimental site to facilitate comprehensive investigations of the requisite design metrics. The prototype was subsequently simulated within this real-world system. This cleaning system utilizes high-quality microfiber cloth to effectively remove dust from panel surfaces without the need for water, making it suitable for arid areas. Additionally, provisions have been included for a water sprinkler to address stubborn stains like bird droppings that cannot be removed solely with the cloth. The overall impact of this mechanism will result in an increased rated power output from the panels, which had previously been compromised due to the mentioned issues.

EMT Model of 20-MW Wind Generator for Real-time Simulation of HVDC Networks

As modern trends demand efficient methods to massively and promptly exploit clean energy, there is an urgent need of solutions that can help the ambition of accelerating the development and integration of larger scale energy systems with the capacity to extract, store, and utilize huge amounts of renewable energy sources. In view of this, the rated power output of the wind generation technology is expected to significantly increase in the near future to enable multi-gigawatt roll outs, e.g. the European plans for Offshore infrastructure development in the North-Sea. Besides, gigantic energy systems shall transmit the power to onshore interconnected systems via HVDC transmission. This paper introduces an EMT model of a 20 MW wind generation system with the conventional back-to-back converter replaced by a combination of an AC to DC converter and a DC to DC converter. While the need of such systems is acknowledged in the literature, the design and performance analysis of high power implementation of such systems have not been addressed yet. The proposed system operates at a voltage level of 100 kV, which can directly transfer power through HVDC interconnection. The designed control aspects are outlined and the resulting dynamic response obtained from realtime digital simulation (RTDS) are discussed. The presented wind generator concept can help in reducing the size of a planned energy system by requiring lesser system components. Also, the system efficiency can be enhanced by decreasing the number of power conversion stages.

A novel geothermal source integrated system to meet the building demands: Exergo-economic and optimization assessment

This study proposes a novel geothermal source integrated system to meet the building demands that combines a solid oxide fuel cell (SOFC), a geothermal source, and a thermoelectric generator (TEG) to achieve enhanced performance. The system is subjected to exergo-economic examination and optimization to determine its thermal performance and cost-effectiveness. Integrating geothermal energy with SOFC can help reduce waste heat and improve overall system performance. Based on the results, it is determined that the cooling system can generate 161.3 kW for building purposes, and the integrated turbine in the cooling system can also produce 891.9 kW of electrical output. The integrated thermoelectric generator modules produce 418.06 kW. Moreover, hybrid systems' energy and exergy efficiencies are 23.29 % and 19.26 %. The case study of the introduced system indicates that by variation of parameters, the systems have different behaviors from thermodynamic and cost points of view. Therefore, multi-criteria optimum finding according to the genetic algorithm is conducted. The optimization results present that in the selected optimal state while using the ideal state, the net output power and overall cost rate are 193307.12 kW and 77.96 $/h.

Experimental evaluation of a WC–Co alloy layer formation process by multibeam-type laser metal deposition with blue diode lasers

A tungsten carbide–cobalt (WC–Co) composite layer was formed on a stainless-steel type 304 (SS304) substrate using multibeam laser metal deposition (LMD) with blue diode lasers. This paper aims to provide WC–Co layer formation with low porosity and high layer formation efficiency by using the multibeam LMD process. The effects of process parameters such as laser output power and powder feed rate are tied together to explain the geometry of the melt layer as well as the fraction of the laser energy used for melting a material. The experimental results show that the porosity rate and layer formation efficiency were recorded at 0.3% and 0.0042 mm3/J, respectively, at the laser output power of 180 W and a powder feed rate of 75 mg/s. It was revealed that layer formation efficiency was dependent on the laser output power.

Characterizing ramp events in floating offshore wind power through a fully coupled electrical-mechanical mathematical model

Floating Offshore Wind Turbines (FOWTs) exhibit a noteworthy nonlinear low-frequency dynamic response during rated and higher wind-wave scenarios, leading to a substantial exacerbation of its power characteristics, power stability, and wind energy forecast reliability. This study develops a fully coupled FOWT model to investigate the impact of wind and wave loads on wind power ramp events (WPREs), which integrates mechanical and electrical factors, including a spar buoy FOWT with generator, converter, and aero-hydro-servo-elastic (AHSE) dynamics. Results indicate that the floating structure enables periodic and significant WPREs of FOWTs, as wave load and platform natural motion causing low and ultra-low frequency response. In contrast to bottom-fixed offshore wind turbines (OWT), FOWTs exhibit a supplementary decline in rated power output ranging from 7.9 % to 40.5 % during WPREs. Moreover, ramp peak mainly depends on the aerodynamic loads, but become sensitive to wave loads characterized by wave heights over 2.52 m. FOWT power performance is highly unstable within the rated wind speed range, under WPREs within ultra short time period, resulting in failure to meet grid standards, emphasizing the external need for targeted power compensation and power signal processing. Overall, this study highlights the importance of pitch motion and wave load impact for WPRE study of FOWTs.