Increase In Output Power Research Articles

Coupled responses of the flow-induced vibration and flow-induced rotation of a rigid cylinder-plate body

In this study, coupled responses of flow-induced vibration and rotation for an elastically mounted cylinder-plate body are numerically investigated at a low Reynolds number of 120. A wide vibrational reduced velocity range of Uy = 3–18 under four rotational reduced velocities Uθ = 5, 8, 12, and 18 are considered. The non-bifurcation responses, bifurcation only in rotation responses, and bifurcation in both vibration and rotation responses are identified. Typical vortex-induced vibration (VIV) responses are recognized when considering the passive rotations, different from the full interactions between VIV and galloping for the vibration-only case. As Uθ increases, the peak vibration amplitudes increase, the onset Uy of the lock-in region becomes larger, and the lock-in region is wider. The phase angles of displacements versus lift coefficients experience a jump from 0° to 180° in the lock-in region, and the larger the Uθ, the wider the Uy range of phase jump. Whether the instantaneous posture of the cylinder-plate body is streamlined or not is determined by oscillation amplitudes and phase differences between displacements versus rotation angles. Streamlined profiles can be achieved under small oscillation amplitudes or when the phase angles are nearly 90°. The 2S (two isolated vortices) vortex shedding mode dominates the initial and desynchronization branch, while the 2P (two pairs of vortices), 2S* (two isolated vortices with tendency to split), and 2T (two triplets of vortices) modes appear in the lock-in region. After the symmetry-breaking bifurcation, the reattachment behavior becomes simpler and the length of the recirculation region is significantly increased, as compared with those in non-bifurcation region. With the above study, a new method of improving energy harvesting from flow-induced vibration, by incorporating passive rotations simultaneously, is first introduced. It is found that passive rotations can enhance the vibration responses and thus lead to the increased output power and energy transfer ratio, although they make less contributions to the total power. Generally, this mechanical system presents a promising opportunity for energy harvesting through flow-induced vibration.

Recovering breeze energy based on galloping enhancement mechanism for smart agriculture

Smart agriculture contributes to a sustainable society. Aiming to provide a self-powered solution for widely distributed sensor nodes in smart agriculture, this work proposes a piezoelectric galloping energy recovery system to recover multi-directional breeze energy in the environment. A galloping enhancement mechanism consisting of an optimal curved-sheet bluff body with a magnet-based bi-stable mechanism is constructed to enhance the energy output from the breeze. Breeze energy recovery is realized by a piezoelectric energy harvester utilizing galloping vibration. Aerodynamic simulations were performed to determine the optimal wide-arc ratio for the curved-sheet bluff body. The magnet-based bi-stable mechanism of three different configuration modes was analyzed and compared. The results of wind tunnel experiments show that the proposed energy recovery system can enhance output power compared to the traditional linear configuration under a breeze. The maximum output power and power growth are 2.81 mW and 49.5 % at 5 m/s wind speed, and a maximum output power increase of 673.3 % was achieved at 3.5 m/s wind speed. The feasibility of powering a low-power agricultural sensor was evaluated in an outdoor experiment. The energy recovery system will effectively manage multi-directional breeze energy recovery, achieving self-powered applications in smart agriculture.

Optimalisasi Kinerja Archimedes Screw Menggunakan Sistem Transmisi Terhadap Output Daya (Watt)

Water energy sources at low head and discharge can be utilized as a generator of electrical energy, one of which is by using the Archimedes screw turbine, the Screw turbine is used in Pico Hydro Power Plants (PLPTH) as a small-scale power plant by utilizing water energy from river flow. The purpose of this research is to optimize the performance of the Archimedes screw turbine Pico Hydro Power Plant so as to produce a better power output. In this study the authors designed an Archimedes screw turbine model with a screw angle of 28°, 5 blade type screw, and 40° turbine tilt. This study focuses on a transmission system using a belt and pulley ratio of 1:3, with two levels of transmission, and a turbine tilt angle of 40°. The method used in this study is the experimental method. As a result, after trials were carried out on a stream located in the Sungailiat Archipelago Fishing Port area, the highest turbine rotation value was 146 rpm and generator rotation 756 rpm, resulting in a power output of 8 watts within 45 minutes of the trial period in the field. This means that after modifying the Archimedes screw turbine with the transmission system and the turbine tilt angle of 40°, the resulting power output increases.

Cryogenic slab RF discharge CO laser with hybrid waveguide-unstable resonators

Dependences of a cryogenic slab radio-frequency discharge CO laser output power on a distance between mirrors of a hybrid negative-branch waveguide-unstable resonator were experimentally studied. The maximum output power was observed at the resonator length longer than the one calculated by taking into account the mirrors radii of curvature. Optimization of the resonator length made it possible to get the output power increase up to 20%–25%. The results obtained can be used for designing not only slab laser systems with hybrid waveguide-unstable resonators, but also for high-power lasers with full-sized negative-branch unstable ones.

Comparison of operational parameters and stability of performance of an automotive SI engine powered by methyl and ethyl alcohols

The article presents research results performed using automotive spark ignition engine run on methyl and ethyl alcohols as well as gasoline as reference fuel. The research was performed on automotive engine of Fiat 1100 MPI type. The subject of the performed analysis was to compare operational parameters of the engine such as: engine power output, overall efficiency, emission of toxic components of exhaust gases, as well as comparison of course of combustion process calculated on the basis of recorded and averaged indicator diagrams, and on the basis of individual combustion cycles. The averaged diagrams were used in analysis of the pressure course during combustion, in analysis of pressure growth rate and heat release rate. Diagrams of individual combustion served for assessment of operational smoothness of the engine when fueled with alcohols. As the reference, parameters measured in case of gasoline fueling were used. The experiments have confirmed stable engine operation on methyl and ethyl alcohols. Increase of engine power output with o 3.8-7.7% was confirmed for methanol and with 1.7-3.3% for ethanol, while increase of the efficiency with 1.5-7.5% was confirmed for methanol and with 1.2-2.5% for ethanol, comparing with gasoline fueling. Obtained results are pointing at possibilities of fueling of modern SI engines with alcohols only, especially including water-logged ethyl alcohol, obtained directly from distillery. This should increase share of alcohols in overall balance of consumed engine fuels.

Pressure energy recovery of LNG integrated with multi-stage feedwater fuel preheaters in a combined cycle power plant

Liquefied natural gas and combined cycle power plants have emerged as solutions to the intermittency of renewable energy sources, but they require innovative approaches for efficiency improvement. This study proposes a novel pressure recovery system, integrated with multi-stage feedwater fuel preheaters, to improve the efficiency of combined cycle power plants connected to natural gas supply stations. The research demonstrates that preheating the fuel to 350 °C reduces fuel consumption by 2.06% while maintaining the gas turbine inlet temperature. Additionally, heating the fuel gas to 210 °C using feedwater, then expanding it to 30 bar in the turbine, leads to a 193% increase in pressure recovery net power output compared to using seawater alone. By combining these two effects, the proposed system improves the overall efficiency of the combined cycle power plant by 1.08%p compared to the basic system without fuel preheating and pressure recovery. Furthermore, implementing pressure recovery and fuel preheating concurrently, rather than sequentially, increases the efficiency by an additional 0.163%p. These findings highlight the potential for this innovative system to maximize the efficiency of combined cycle power plants, and pave the way for further exploration of new approaches to enhance the performance of liquefied natural gas power plants.

Performance Evaluation of Aquaponics-Waste-Based Biochar as a Cathode Catalyst in Sediment Microbial Fuel Cells for Integrated Multitrophic Aquaculture Systems

The sustainable development of aquaculture faces a significant challenge due to the need for the frequent treatment of aquacultural waste. This research presents a pioneering solution by concurrently utilizing aquacultural waste to produce biochar and enhancing a sediment microbial fuel cell (SMFC)’s treatment efficacy for waste generated from the integrated multitrophic aquaculture (IMTA) system. The water quality parameters of the aquacultural pond water were analyzed, and synthetic wastewater was prepared to validate the system’s efficiency. Over a period of more than 50 days, the SMFC was operated and monitored, yielding an average chemical oxygen demand (COD) removal efficiency of 86.31 ± 2.18%. The maximum operating voltage of the SMFC reached 0.422 V on the 21st day of operation when connected to an external resistance of 975 Ω. A novel-activated aquacultural biochar catalyst was synthesized from aquaponics waste and used as a cathode catalyst, substantially improving the SMFC’s performance. Characterization studies demonstrated that the aquacultural biochar catalyst was an active electrocatalyst, accelerating the oxygen reduction reaction rate and leading to increased power output and overall efficiency of the SMFC. The SMFC utilizing the aquacultural-waste-based biochar cathode catalyst showcased the highest maximum power density, with a range of 101.63 mW/m2 (1693.83 mW/m3), and the lowest internal resistance, indicating superior performance. These results validate the reliability of implementing SMFCs in actual aquaculture systems. A novel modular design for SMFC reactor-assisted small-scale integrated poultry–fish culture systems is proposed for further practical application in real-life aquaculture settings. This research contributes to finding sustainable and effective methods for waste treatment for aquaculture, promoting the development of environmentally friendly practices in the industry.

Vertical limit reduction of chimney in solar power plant

The practical feasibility to install solar updraft tower (SUT) for power production require huge capital investment and difficulties in installing tall giant chimney structure. The chimney is the most expensive element of SUT and typically covers one-fourth of the total SUT cost. Previous finding has shown that a divergent chimney shows significant increase in power output than a conventional design for the same height. This paper deals with the unexplored scientific question: for how much height of divergent chimney can be dispensed with for the same or higher performance of a conventional design? Using an experimentally validated numerical model, we systematically investigated height reduction of chimney (and hence substantial cost) of a high performing divergent chimney whose power output is identical with a long unstable costly conventional cylindrical chimney. The conventional cylindrical design was chosen as the conventional SUT prototype installed at Manzanares, Spain in the year 1980. Results show that it is possible to reduce the vertical limit by about 80% of the height of conventional cylindrical chimney. Further, the cost analysis estimated for each SUT designs and the optimum divergent chimney SUT holds payback period 40% less than the conventional SUT. The proposed designs would be useful for floating chimney as well made of fabric material with light density air filled to keep short chimney height upright vertically to resolve the instability issues with the conventional tall chimney structure during high wind speed environmental conditions The present investigation would assist scientific community to develop more advance clean energy-based power generation systems to achieve net-zero carbon emissions targets.

Computational investigation of combined solar chimney power plant with gas power plant in different working conditions

Numerous studies have recently focused on enhancing the efficiency of solar chimney power plants (SCPP) and increasing their output power during periods of limited solar radiation. One such study proposes a novel solution: combining an SCPP with a gas power plant to create a hybrid power plant that generates power consistently, day and night. The system involves burying pipes underground and channeling the hot gas from the gas power plant through them, rather than releasing it into the atmosphere. This process increases the temperature of the soil beneath the canopy, which in turn raises the air temperature and the velocity of the air. The resulting decrease in air density leads to an increase in output power. Our results show that the performance of solar chimney of soil ground with buried pipe is about 30% higher than sand domain.

Is the Actuator line method able to reproduce the interaction between closely-spaced Darrieus rotors? a critical assessment on wind and hydrokinetic turbines

The deployment of multiple closely-spaced Darrieus turbines has recently gained interest in the academic and industrial sectors due to their potential to increase power output and wake recovery. However, the computational cost of accurate three-dimensional, blade-resolved CFD analyses rapidly becomes unfeasible as long as multiple rotors are added, putting emphasis on the need for a more practical, yet accurate, simulation method. Based on recent assessments, the Actuator Line Method (ALM) has been shown to represent the most interesting solution for Darrieus turbines’ simulations. However, since the blade-flow interaction is not solved, no evidence was available to date on whether ALM can capture all the physical phenomena related to turbine mutual interaction.In this study, the reliability and limitations of the ALM in simulating closely-spaced Darrieus turbines were assessed using two pairs of turbines with varying geometrical and operational characteristics, focusing on turbine loads, local flow field, and wake development. The results demonstrate that the ALM is effective for simulating twin-rotor Darrieus turbines, particularly at medium and high tip-speed ratios, providing satisfactory predictions of instantaneous blade loads and capturing the increase in torque due to the mutual interaction between adjacent rotors. The ALM is also able to accurately reproduce the flow field across the twin rotors, as demonstrated through Proper Orthogonal Decomposition (POD) analysis of the wake flow field. With an average simulation time of 7 h/rev/core, compared to 508 h/rev/core for blade-resolved CFD, this study provides evidence that the ALM is a low-cost and reliable tool for simulating closely spaced Darrieus turbines, thus representing the most suitable tool to develop new VAWT applications like floating wind turbines or hydrokinetic installations.

Multi-objective optimisation on steady-state thermodynamic parameters of S-CO2 recompression Brayton cycle power generation system for marine waste heat recovery

Analysis of thermodynamic parameters’ effects on the S-CO2 recompression Brayton cycle for recovering the main engine exhaust gas waste heat of an ocean-going 9000 TEU container ship are carried out first in this paper. NSGA-II algorithm-based multi-objective optimizations are conducted to maximise net power output and exergetic efficiency as well as to minimise the levelized cost of energy (LCOE). The final optimal result from Pareto front solutions is decided by decision-making processes. The results show that the LCOE increases along with the enhancement of net power output and exergetic efficiency, and the maximal objectives always appear near the upper boundary of exhaust gas temperature. The final optimal result decided by TOPSIS decision-making has higher rationality and accuracy than that obtained by the LINMAP method. Regarding the final optimal results of triple-objective and dual-objective optimizations obtained by the TOPSIS method, the former achieved more reasonable results, since its optimal net power output and exergetic efficiency are 1.29% and 5.11% higher than the latter, while its LCOE increased by 2. 28% as a result of the increase of the net power output. The recompression Brayton cycle is better for recovering the exhaust gas waste heat in ships compared with the simple recuperative cycle without recompression.

Increasing Output Power of a Microfluidic Fuel Cell Using Fuzzy Modeling and Jellyfish Search Optimization

Increasing Output Power of a Microfluidic Fuel Cell Using Fuzzy Modeling and Jellyfish Search Optimization

Adaptive energy harvesting approach for smart wearables towards human-induced stochastic oscillations

Harvesting diverse renewable energy sources from humans offers an effective approach to achieving cleaner production and sustainable development. The integration of self-powered smart wearables enables continuous power supply for long-term operation of outdoor civilian and military electronics, especially in situations with limited access to conventional power sources. Resonant energy harvesting schemes working at the dominant frequencies of human movement can trigger large mechanical oscillations and significantly enhance the generation of electrical power. This study presents the development of a nonlinear two-degree-of-freedom (2DOF) resonant energy harvesting system with a maximum power point tracking (MPPT) algorithm that adapts to individual human differences and stochastic motion patterns. Through an analysis of the system characteristics based on equivalent circuit modeling, it is found that the electrical damping of the harvester plays a crucial role in determining the actual power output, and the relationship between its optimal value and the oscillation frequency is unique. Thereby, an energy harvesting circuit with an adaptive MPPT algorithm is developed to optimize the electrical damping in real time by applying a novel Perturb and Observe technique based on the average power over each time period. In addition, a variable-step search method and a special convergence judgment are proposed to enhance the tracking speed. The sensitivity analysis of algorithm parameters indicates that the time period and power tolerance need to be reasonably selected to strike a balance between search speed and accuracy. The results of constant motion pattern tests show that the proposed algorithm with a variable-step search method exhibits superior search speed and accuracy over fixed-step configurations. The results of variable motion pattern tests reveal an increase in the actual system power output of up to 194% compared to the conventional fractional open-circuit voltage (FOCV) algorithm. Finally, the system adaptability test is conducted to validate the MPPT efficiency in four resonant systems. The results showcase an impressive MPPT efficiency of 93%–99%, demonstrating its reliability and robustness in various application scenarios.

Power generation of annular thermoelectric generator with silicone polymer thermal conductive oil applied in automotive waste heat recovery

The annular thermoelectric generator (ATEG) matches the shape of the exhaust pipe. To improve the power generation efficiency of the ATEG in automobiles, a scheme is proposed to use a silicone polymer-based thermal conductive oil to transfer heat from the exhaust. Based on this concept, a new type of concentric tube heat exchanger is designed. A finite element model of the new system is established by considering temperature gradients, temperature dependence, and fluid resistance characteristics. Numerical simulations are performed to investigate the effects of exhaust parameters, thermal oil parameters, and heat exchanger structure on thermoelectric performance. The findings demonstrate a 15.2% increase in maximum output power of the new generator compared to a conventional ATEG, accompanied by a 19% decrease in the optimal thermoelectric module area. Furthermore, the net power first increases and then decreases with increasing thermal oil mass flow rate. The thermal oil mass flow rate can be adjusted in real-time based on fluctuations in exhaust parameters to achieve peak net output power. Finally, optimal fitting relationships between the heat exchanger dimensionless diameter and the total diameter, as well as between exhaust parameters and the optimal thermal oil mass flow rate, are obtained through parameter analysis and derivation.

Improvment of combined solar chimney power plant with gas power plant

Recently, several researches have been done to improve the perfomance of solar chimney power plants (SCPP) and increase their low output power during hours when the solar radiation is limited. In this study, by combining a SCPP and a gas power plant, the output power is increased and the power output of the combined power plant can be gained at all hours of the day and night. Pipes are buried under the ground and the outlet hot gas from gas power plant flows through the buried pipes instead of being released into the atmosphere through the stacks. Flowing of hot gas through the buried pipes at the soil under the canopy increases the temperature of soil which is exposed to the solar radiation. Increasing of the soil temperature leads to the growth in the value of air temperature under the canopy. The air density reduces as the air temperature increases which leads to the increase of air velocity and output power. By applying the buried pipes, the output power is not zero during the hours when there is no radiation flux. The results for air temperature, heat loss and output power are studied in detail and it is shown that the use of buried pipes in which hot gas flows leads to the increase of the output power of SCPP by 554%, 208% and 125% at the radiation flux of 200 W/m2, 500 W/m2 and 800 W/m2, respectively.

Reverse compositional strategy of multiple quantum wells for the AlGaN-based deep-ultraviolet laser diodes

Due to the high activation energy/ionization energy as Mg increases, Al-rich AlGaN-based deep-ultraviolet (DUV) laser diodes have a structure that is difficult to perform Mg p-doping. The performance of this type of laser diode is affected by the content of Al in the quantum barriers of multiple quantum wells, and reducing the Al content in the laser diodes may simplify its structure and make Mg p-doping less difficult. The proposed device can be improved by adopting the reverse compositional strategy of multiple quantum wells with the Al content of quantum barriers 10% lower than that of quantum wells as opposed to the reference device where the Al content of the quantum barriers is 10% higher than that of the quantum wells. The simulation results have been observed theoretically in terms of the performance parameters such as band diagrams, optical confinement factor, peak gain, emitted power, stimulated recombination rate, and carrier concentration. Two deep ultraviolet laser diode devices have been analyzed in this study within the wavelength range of 267 nm. The proposed device has superior performance with a larger optical confinement factor and increased output power with reduced injection current.

A Study on Optimal Indium Tin Oxide Thickness as Transparent Conductive Electrodes for Near-Ultraviolet Light-Emitting Diodes.

This research study thoroughly examines the optimal thickness of indium tin oxide (ITO), a transparent electrode, for near-ultraviolet (NUV) light-emitting diodes (LEDs) based on InGaN/AlGaInN materials. A range of ITO thicknesses from 30 to 170 nm is investigated, and annealing processes are performed to determine the most favorable figure of merit (FOM) by balancing transmittance and sheet resistance in the NUV region. Among the films of different thicknesses, an ITO film measuring 110 nm, annealed at 550 °C for 1 min, demonstrates the highest FOM. This film exhibits notable characteristics, including 89.0% transmittance at 385 nm, a sheet resistance of 131 Ω/□, and a contact resistance of 3.1 × 10-3 Ω·cm2. Comparing the performance of NUV LEDs using ITO films of various thicknesses (30, 50, 70, 90, 130, 150, and 170 nm), it is observed that the NUV LED employing ITO with a thickness of 110 nm achieves a maximum 48% increase in light output power at 50 mA while maintaining the same forward voltage at 20 mA.

Modelling and optimization analysis of a novel hollow flexible-filler-based bulk thermoelectric generator for human body sensor

Thermoelectric generator (TEG) is a promising technology for self-powered wearable electronics and sensors. Usually, polydimethylsiloxane (PDMS) is selected as bulk thermoelectric gap filler to make the TEG flexible. However, PDMS has much higher thermal conductivity than air causing considerable thermal shortcut and efficiency degradation. In this study, a novel hollow PDMS-filler design is proposed to enhance the TEG performance. A well-validated three-dimensional thermal and electrical coupled model is developed to assess effects of longitudinal and transverse hollow structures on maximum output power and corresponding optimal fill factor of the flexible TEG, and to reveal impact of key geometrical and physical parameters on design optimization of the TEG. Results show that, (1) as height of the hollow structure increases, the output power increases linearly, while the optimal fill factor decreases sharply; (2) the transverse-hollow structure is more effective than the longitudinal-hollow structure to create higher power; (3) the transverse-hollow structure can approximately double the output power while halve the optimal fill factor; (4) the transverse-hollow structure combined with both-sides high-thermal-conductivity layers can increase output power up to 137.34 μWcm−2. Such design of hollow PDMS filler could open a window of opportunity to the next generation efficient yet low-cost flexible TEG.

A Novel MPPT Method Based on PSO and ABC Algorithms for Solar Cell

The maximum power point tracking (MPPT) system ensures that the solar cell operates at its maximum power point, which is the point at which it produces the most power for a given set of conditions. This study uses an artificial bee colony (ABC) algorithm and particle swarm optimization (PSO) algorithms to optimize the boost converter. The ABC and PSO algorithms help to optimize the boost converter by finding the best possible duty cycle and other parameters that maximize efficiency. The resulting duty cycle of 20% produced the highest efficiency of 78.26% obtained from the boost converter. A system-wide test was conducted between 9:00 and 11:10 WIB. In MPPT systems using boost converters with the PSO algorithm, the average power is 16.80 W, while in MPPT systems using boost converters with the ABC algorithm, the average power is 14.53 W. The novelty of the study discusses a system designed to optimize power by using a boost converter in order to increase power output from solar panels. The algorithms PSO and ABC are used to analyze the data from the PV and adjust the converter parameters to optimize the output in order to increase the efficiency of the system.

Self-Powered Mechanical Energy Sensor Application of SnO2/Ag and PMMA/ITO Nanocomposites via Triboelectric Effect

The triboelectric nanogenerator is a state-of-the-art device for addressing the growing problem of meeting the world's ever-increasing energy needs by converting mechanical energy into electrical energy. Using the popular semiconductor SnO2 nanostructured thin films as a triboelectric layer over contact regions, as opposed to polymers with lesser performance, increases the output power and life time of nanogenerators. In order to design a triboelectric nanogenerator, deposited thin film SnO2 is used as a friction layer with Ag electrode after heat-treatment at 623 K with a contrary layer of PMMA poly (methyl-methacrylate) with ITO electrode. The structural and electrical properties were analyzed by using scanning electron microscopy (SEM), electro-impedance spectroscopy (EIS) and atomic force microscopy (AFM) measurements. The increased output power of the triboelectric nanogenerator is attributed to the nanoscale PMMA contact charge created by tunneling electrons in the SnO2/Ag nanocomposite thin film layer. Due to its proximity to the PMMA/ITO surface, the SnO2/Ag layer causes electron field emission, and tapping the SnO2/Ag layer may result in electron cloud overlap. Similar to a semiconductor/insulator interface, the Fermi level of SnO2 plays a crucial role in electron transport. The system efficiency stated as a touch detector in a conventional keyboard that generates its own power is revealed in part by an analysis of its operating state up to the 4V.