Electric Power Research Articles

Development and Outlook for Self-priming Pumps

Background: Self-priming pumps are a type of general mechanical equipment that is widely used in the petroleum, chemical, electric power, metallurgy, mining, shipbuilding, light industry, agriculture, civil defense, and other departments, and they play an important role in the global economy. The pump system is the most common piece of equipment that consumes the most electricity, and reducing the energy consumption of the pump will save a significant amount of energy. Objective: For the benefit of scholars and engineers, this paper summarizes the most recent research on self-priming pumps, analyzes their solutions to the problem of reducing energy consumption, and discusses their advantages and disadvantages. Methods: The typical self-priming pump patents are outlined below based on the many functions of the improved self-priming pump structure, including pump body protection, high efficiency, and energy savings, ease of movement, and improved seal. The current self-priming pump patents are used to examine the development trend for these pumps. Results: The fundamental issues with self-priming pumps are outlined and studied through comparisons of various types and functions, and a future course for their development is suggested. Conclusion: The development of self-priming pump technology benefits from the improvement of self-priming pump structure. A self-priming pump with a straightforward design, automation, high efficiency, and energy conservation has a promising future.

Comparative experimental analysis of monocrystalline and polycrystalline photovoltaic panel through hybrid phase change material

Photovoltaics thermal management is utmost necessary as continuous heating of the module decreases the performance. This paper presents a comparative study in terms of performance of two photovoltaic modules namely monocrystalline and polycrystalline using hybrid phase change materials (PCMs). The hybrid PCMs of RT31 and RT 44HC were prepared by method of stirring. The final prepared hybrid PCMs were poured at the back of panel and panel was covered. The purpose of these experiments is to improve the efficiency of polycrystalline and monocrystalline photovoltaic modules and comparing which technology is more efficient having hybrid PCM. The experiments were performed under the room conditions in Taxila, Pakistan. The output parameters of the photovoltaic module appeared to be strongly dependent upon the solar irradiance. The power output and efficiency of monocrystalline and polycrystalline photovoltaic module were measured. The monocrystalline panel maximum temperature was 36.59 °C as compared to polycrystalline panel which was 40.23 °C. As the radiation intensity increased till noon, electrical power was improved, and it was 6.52 W in monocrystalline panel as compared to polycrystalline panel which was 6.32 W. Electrical conversion efficiency was also observed, and it was maximum up to 11.84 % in monocrystalline panel. The higher performance was observed in case of monocrystalline panel having hybrid in terms of performance as compared to polycrystalline panel.

ANN-based Maximum Power Point Tracking Technique for PV Power Management under Variable Conditions

Due to the increasing energy demand, traditional fossil fuels are gradually decaying day by day as analyzed by many researchers. Fossil fuels are not sufficient to fulfil the requirement of energy demand and it also produces greenhouse gas emissions. In this regard, worldwide research is going on related to renewable energy sources (RESs) like solar photovoltaic (SPV), wind turbines, fuel cells etc. The source of SPV is plentiful and environment friendly which converts solar radiation to non-linear electrical power. This power is not suitable for a stable system. Therefore, the maximum power point tracking (MPPT) controller is required to find the optimum maximum power point (MPP) to the load. The MPPT technology regulates the duty-cycle in favour of the DC-DC converter to continuously obtain maximum power from the SPV arrays. In the past few decades, the learning of MPPT techniques has made substantial progress in the RESs. This research article analyzes the performance of various MPPT techniques in the proposed SPV framework. The main investigation is to assess different MPPT techniques to optimize power from the SPV framework. The artificial neural network (ANN)-MPPT method has been observed to be more effective in output power production and transient response about the MPP than conventional perturb and observe (P&O)-MPPT and fuzzy logic controller (FLC)-MPPT technology.

Simulasi karakteristik mesin termoakustik pembangkit listrik dengan penambahan model kerugian minor dari dua segmen konis

Acoustic energy output level from regenerator segment of a thermoacoustic engine model is attenuated along it’s loop due to several conditions including minor losses. This article discusses the result of Delta EC simulation of a thermoacoustic engine model acting as simple electric power generator that inserted with two conical segments. The cone segments are capable to lower the energy loss which in turn improve the overall performance of the engine in term of nett heat to acoustic energy conversion efficiency. Combined acoustic energy loss induced by both cones is equivalent to 4.94 watts minor losses. At this condition, regenerator segment amplifies the incoming acoustic energy flow of 57.02 watt up to 93.57 watt, which is equals to 36.55 watts acoustic amplification. It leads to increasing of overall engines heat to acoustic efficiency into 14.05%, which is 1.29% higher than those at the case of without cones. This engine performance improvement addressed to smoother streamline of working fluid flow inside the loop.

Digitalization and Decarbonization of Sri Lanka's Electric Power System: A Way Forward for Sustainability

The global energy landscape is undergoing a transformative shift driven by the dual imperatives of digitalization and decarbonization, essential for creating sustainable and resilient power systems (Lichtenthaler, 2021, [1]). This transformation is particularly critical for developing nations like Sri Lanka, where the integration of smart technologies and renewable energy sources can significantly enhance system efficiency and contribute to a robust response to climate change challenges (Lichtenthaler, 2021, [1]). This paper examines the potential of leveraging advanced digital technologies—such as artificial intelligence, big data analytics, and the Internet of Things—to optimize energy management and facilitate a swift transition toward a low-emission economy in Sri Lanka, while addressing the socio-economic implications of this transition. Furthermore, this study highlights the importance of fostering a circular economy through these technological advancements, emphasizing that innovative solutions can not only improve energy efficiency but also contribute to broader sustainability goals, ensuring equitable access to resources and combating the adverse effects of climate change. Through this lens, the investigation underscores the necessity of a holistic approach that integrates digital transformation with sustainable practices, enabling the decoupling of economic activity from resource depletion and environmental degradation, thereby fostering a resilient energy future for Sri Lanka.

The effectiveness of duty cycling technique on air conditioning system during break period for comfort, energy and cost savings: A real case study in health center

This paper investigates the potential of duty cycling techniques for air conditioning (AC) systems in producing energy and cost savings and the impact on the indoor thermal environment, air quality, and environmental sustainability. The real case study concentrated on energy consumption practice during the break period between 13:00 to 14:00 in a lobby area of a Health Center. Site data measurements of electrical input power, energy, indoor air temperature and humidity, and indoor carbon dioxide (CO2) concentration were conducted. Two zero-cost strategies were studied and results were compared to baseline conditions. In general, the results show that all strategies can meet the indoor thermal environment and air quality requirements, except room temperature for Strategy 2 which ranges on average between 26.71 to 26.82C. In addition to the instant payback period (0 years), the results also indicate that as compared to baseline condition, Strategies 1 and 2 led to annual energy and cost savings of around 759.2 kWh (USD 64.40) and 1250.6 kWh (USD 106.08), respectively. In terms of environmental sustainability, Strategies 1 and 2 can avoid environmental CO2 emissions by 444.13 and 731.60 kg of CO2 per year, respectively. Due to these reasons and if the sensitivity of occupant comfort to room temperature during the break period can be tolerated, it is proposed that Strategy 2 is the best option for the AC system operation during the break period. Considering other buildings also adopted the same strategy, this small action can lead to a high impact, not only on energy and cost savings but also on environmental sustainability in the future.

Modeling the Operating Conditions of Electric Power Systems Feeding DC and AC Traction Substations

Modeling the Operating Conditions of Electric Power Systems Feeding DC and AC Traction Substations

Performance Analysis of a Self-Decarbonizing Combustor

Abstract Hydrogen is envisioned to be a key decarbonization solution for fossil fuel-dependent power generation and aviation industries. At present, a significant fraction of the generated electrical power is derived from natural gas. As such, the external energy needed for hydrogen generation, often sourced from fossil fuels, results in CO2 emissions, compromising overall carbon neutrality. Instead, the processes of hydrogen generation can be energetically coupled with the combustion process, in situ, to eliminate external energy requirements. To that end, a novel self-decarbonizing combustor (SDC) has been conceptualized, integrating methane pyrolysis with the combustion process that can in principle decarbonize many contemporary power generation technologies. The underpinning methane pyrolysis process enables in situ pre-combustion capture of solid carbon, while simultaneously generating hydrogen. Consequently, CO2 emissions resulting from the combustion of processed, hydrogen-enriched fuel are mitigated. This study provides a comprehensive analysis, delineating the operating principle and the effect of some of the important governing parameters on the performance of the self-decarbonizing combustor. These parameters, including fuel temperature, residence time, pressure, and catalysis, are studied in the context of potentially applying the proposed concept to natural gas-based decarbonized electrical power generation. Investigating fuel chemistry, combustion exhaust, and carbon structure and morphology under varying process parameters enhances our comprehension of the SDC. Additionally, its self-sufficient nature eliminates the need for separate hydrogen production, storage, and transportation infrastructure, highlighting its potential as a scalable and realizable technology.

Simultaneous costs minimizing in electricity and gas micro-grids with the presence of distributed generation

Distributed generation can actively participate in the day-ahead markets, real-time power balance, and wholesale gas markets to achieve various goals, such as supplying gas to various electric power generation plants. A multi-objective network with two types of loads is considered in this paper. The reason for the simultaneous optimization of these two networks is that these two energy carriers are dependent on each other and gas is needed to produce electricity, so this issue can be addressed with a multi-objective function. The simulation carried out in this article is coded in GAMS software as a mixed integer linear programming (MILP). The efficiency of gas turbines and fuel cells in this article is dependent on their working point, and considering the exact model of these resources and the relationships related to the calculation of their fuel consumption is non-linear. On the other hand, a binary variable has been used to show the charging and discharging state of the storage and the on-and-off state of the gas turbines. Therefore, the problem considered in this article is a MILP problem. The results of this article are the proper planning of charging and discharging of the energy storage system with the proper planning of the power generation of different energy sources considering the network loads in two optimized and non-optimized scenarios.

Parameters Tailoring on the Deposition of Hydroxyapatite by Pulsed Electrical Discharge

The creation of strong adhesive layers of hydroxyapatite-based bioceramics (with or without bioinert metals, such as Ta, Ag, and Ti) on biocompatible metallic supports enhances the local biofunctionalization of surfaces. The processing of electroconductive materials using electrical impulse discharges is versatile, enabling precise coating of selected areas with perfectly adherent layers of varying thicknesses. This study aims to quantify the effects of varying the electrical power from the source generating the impulse discharge and the specific processing time per unit area of the cathode (made of titanium alloy) on the relative mass increase of the cathode. The anode comprised a mixture of hydroxyapatite powder and a self-polymerizing electroconductive acrylic resin in a tantalum sheath. The effects of the parameter adjustments on single-layer deposition adherence were quantified using a central composite design to build a second-order orthogonal model. The most significant difference in relative mass was observed with a low-power source (5 W) ensuring the electrical discharge impulse, combined with the longest specified surface treatment time (17.5 s/cm2 on a 4 cm2 surface) for a single layer presenting the largest mass increase of 0.153% of the original mass. This study aimed to enhance the performance of medical implants by optimizing surface biofunctionalization through robust hydroxyapatite-based bioceramic adhesive layers on metallic supports, determining the optimal electrical power and processing time for cathode mass increase during deposition processes, and analyzing parameter adjustments using second-order statistical orthogonal central composite programming, with a focus on single-layer deposition to identify significant differences in relative mass under specific conditions.

Early Design Stage Evaluation of All Electric Aircraft Power Systems Focusing on Long-Term Behavior

In the aircraft industry, there is a shift towards more and all-electric power systems resulting in great research efforts on single components like batteries. At the same time there is an increasing need to investigate and evaluate the long-term behavior of the whole electric power system to ensure safe and sustainable aircraft operation. Focusing on this challenge, the objective of this article is to propose a framework for electric power system assessment in the early design stages. In particular, the focus is on identifying and handling uncertainties regarding failure behavior and degradation, both on the component and system level. The evaluation of different power system topologies is based on the integration of Model-Based Systems Engineering and robust design methods. In this context, another central aspect is the definition of system and component requirements derived from the flight mission profile. SysML diagrams are used to define use cases and possible system topologies. Sensitivity of degradation effects are evaluated using robust design methods. The application of the framework and these methods is illustrated using a short-range aircraft with an all-electric power system. The results highlight the applicability of the framework to cope with the uncertainties that occur in the early design stages and point out fields of further research.

The Problem of Integrating Digital Twins into Electro-Energetic Control Systems

The use of digital twins (DTs) in the electric power industry and other industries is a hot topic of research, especially concerning the potential of DTs to improve processes and management. This paper aims to present approaches to the creation of DTs and models in general. It also examines the key parameters of these models and presents the challenges that need to be addressed in the future development of this field. Our analysis of the DTs and models discussed in this paper is carried out on the basis of identified key characteristics, which serve as criteria for an evaluation and comparison that sets the basis for further investigation. A discussion of the findings shows the potential of DTs and models in different sectors. The proposed recommendations are based on this analysis, and aim to support the further development and use of DTs. Research into DTs represents a promising sector with high potential. However, several key issues and challenges need to be addressed in order to fully realize their benefits in practice.

Quantifying future carbon emissions uncertainties under stochastic modeling and Monte Carlo simulation: Insights for environmental policy consideration for the Belt and Road Initiative Region

This study critically examines future carbon (CO2) emissions in the Belt & Road Initiative (BRI) region, considering factors such as energy consumption, economic growth, population growth, and population density. The objective of this study is to identify critical areas of higher emissions, which require policy intervention capable of strengthening sustainability in the BRI compact. A combined approach of stochastic modeling and Monte Carlo simulations was employed, utilizing panel data from 45 countries in the BRI region from 1990 to 2021. Results confirm that emissions are higher in all scenarios in direct proportion to electric power consumption, population growth, and Gross Domestic Product (GDP) growth. In scenarios with high emissions, a continuous and significant upward trend in CO2 emissions was observe. The medium emissions scenario exhibited a more moderated rise in emissions, suggesting a balance between economic development and environmental considerations. Critical areas for future environmental policy-making resides in electric power consumption, population growth, and GDP growth. The study strongly recommends for a shift from the current focus on road and railway infrastructure to renewable energy infrastructure, green innovations and efficient technology transfer to member countries. Without this, the BRI region is likely to face increased emissions, posing significant challenges to future sustainable development and global environmental sustainability.

Thermodynamic Analysis of a Marine Diesel Engine Waste Heat-Assisted Cogeneration Power Plant Modified with Regeneration Onboard a Ship

The objective of this study is to perform a thermodynamic analysis on a marine diesel engine waste heat-assisted cogeneration power plant modified with regeneration onboard a ship. The proposed system utilizes the waste heat from the main engine jacket water and exhaust gases to generate electricity and heat, thereby reducing the fuel consumption and CO2 emissions. The methodology includes varying different turbine inlet pressures, extraction pressures, and fractions of steam extracted from the turbine to evaluate their effects on the efficiency, utilization factor, transformation energy equivalent factor, process heat rate, electrical power output, saved fuel flow rate, saved fuel cost, and reduced CO2 emissions. The analysis demonstrates that the proposed system can achieve an efficiency of 48.18% and utilization factor of 86.36%, savings of up to 57.325 kg/h in fuel, 65.606 USD/h in fuel costs, and 180.576 kg/h in CO2 emissions per unit mass flow rate through a steam turbine onboard a ship.

Theoretical Study of the Strong Piezo-phototronic Effect in 2D Monochalcogenides for Multi-Junction Solar Cells

Abstract The piezophototronic effect is a new scientific area that investigates the synergistic interactions of piezoelectric, semiconductor, and photoexcitation features. This effect is seen in crystals lacking inversion symmetry, where applied strain alters electronic transport and provides a way to modify material properties. Monolayer 2D semiconductors, such as TMDCs and group IV monochalcogenides, have higher piezoelectric coefficients than conventional piezoelectric materials. This study suggests creating a stable and high-performance Multijunction Solar Cell (MJSC) using the piezo-phototronic effect. The emphasis is on single-type 5-layer 2D monochalcogenides such as SnS, SnSe, GeS, and GeSe, which employ band gap engineering. Surprisingly, the ultrathin parallel-connected solar cell achieves an electric power conversion efficiency of over 31% when tested under blackbody radiation, exceeding the recognized S-Q limit. The piezophototronic effect improves solar cell performance while also addressing voltage mismatch issues. This work introduces a novel approach to developing and manufacturing high-efficiency and robust monolithic multijunction photovoltaic solar cells (MJPSC) based on 2D monochalcogenides.

Effect of DG penetration on hybrid relay coordination using user-defined dual-setting directional overcurrent relays and distance relays

ABSTRACT The efficient coordination of the distance and directional overcurrent relays (DOCRs) is jeopardized by the massive deployment of renewable distributed generation (DG) into electrical power networks. The two key aspects influencing the relay coordination are the bidirectional flow of current and increased short-circuit currents due to DG integration. This study investigates the consequences of variable DG penetration on the distance and dual-setting DOCRs (DS-DOCRs) coordination. As a result, common optimal relay settings have been obtained that can be utilized for variable DG penetration levels in modified IEEE-14 bus test system. For the distance relays (DRs), a fixed zone 1 and variable zone 2 operation have been considered. The proposed combined protection scheme is tested on a modified IEEE-14 bus test system using DS-DOCRs and DRs. The relay coordination problem is formulated as a constrained non-linear optimization problem and solved by genetic algorithm (GA) and gray wolf optimization (GWO). In this paper, DS-DOCRs with user-defined relay characteristics have demonstrated superior performance in line protection compared to conventional DOCRs with normal inverse (NI) characteristics. In addition, a comprehensive comparative analysis of optimization algorithms has been performed between GA and GWO algorithms.

FLOW AND HEAT TRANSFER IN A RIBBED CONVERGING-DIVERGING U-DUCT UNDER ROTATING AND NON-ROTATING CONDITIONS

Abstract A numerical study based on steady RANS with the SST turbulence model was performed to investigate the flow and heat transfer in a ribbed U-duct with a rectangular cross section that converges linearly in the radially outward direction and diverges linearly in the radially inward direction under rotating and non-rotating conditions. Parameters examined include rotation number (Roi = 0, 0.0219, 0.0336, 0.0731), Reynolds number (Rei = 46,000, 100,000, and 154,000), and the duct's taper angle (α = 0° and 1.41°) under conditions relevant to gas turbines used for electric power generation. Results obtained show that increasing the taper angle from 0° to 1.41°, which appears negligibly small, significantly increases both the friction coefficient and the Nusselt number whether there is rotation or not. With rotation at Roi = 0.0336 and Rei = 100,000, the maximum increase in the average friction coefficient and Nusselt number was found to be 41.7% and 36.6% respectively. Without rotation at Rei = 46,000, those are 11.5% and 14.7% respectively.

Advanced Materials for Energy Harvesting and Soft Robotics: Emerging Frontiers to Enhance Piezoelectric Performance and Functionality.

Piezoelectric energy harvesting captures mechanical energy from a number of sources, such as vibrations, the movement of objects and bodies, impact events, and fluid flow to generate electric power. Such power can be employed to support wireless communication, electronic components, ocean monitoring, tissue engineering, and biomedical devices. A variety of self-powered piezoelectric sensors, transducers, and actuators have been produced for these applications, however approaches to enhance the piezoelectric properties of materials to increase device performance remain a challenging frontier of materials research. In this regard, the intrinsic polarization and properties of materials can be designed or deliberately engineered to enhance the piezo-generated power. This review provides insights into the mechanisms of piezoelectricity in advanced materials, including perovskites, active polymers, and natural biomaterials, with a focus on the chemical and physical strategies employed to enhance the piezo-response and facilitate their integration into complex electronic systems. Applications in energy harvesting and soft robotics are overviewed by highlighting the primary performance figures of merits, the actuation mechanisms, and relevant applications. Key breakthroughs and valuable strategies to further improve both materials and device performance are discussed, together with a critical assessment of the requirements of next-generation piezoelectric systems, and future scientific and technological solutions.

Повышение термоэлектрической эффективности устройств преобразования энергии за счет использования наноструктурированных материалов

Background: Thermoelectric materials have received much interest because of their capacity to transform thermal energy into electrical power, providing a sustainable method for energy collecting. Despite substantial study, the actual use and effectiveness of these materials require more investigation as they move from laboratory to industrial settings. Objective: This study's objective is to provide a thorough analysis of the evolution of thermoelectric materials, from their fundamental theoretical underpinnings to their integration into devices, highlighting material science advances that improve their efficiency and applicability. Methods: We did a thorough review of current research that focused on new materials, improved synthesis procedures, and innovative design strategies to improve the thermoelectric figure of merit. Furthermore, we investigated the procedures of integrating these materials into devices, taking into account both performance measurements and scalability. Results: The findings show substantial advances in the fabrication of nanostructured thermoelectric materials, which significantly boost the Seebeck coefficient while preserving electrical conductivity. We also found essential solutions for optimising device architecture that simultaneously boost heat management and efficiency. Conclusion: Breakthroughs in material science and engineering are driving the fast integration of improved thermoelectric materials into practical systems. Future research should concentrate on the scalability of these technologies and their integration into a larger range of renewable energy systems, therefore improving their economic feasibility and environmental effect.

Dispersion compensation design of high-density stacking RFSS absorbers for wideband applications

Abstract A dispersion compensation design absorber realized by high-density stacking resistive frequency selective surface (RFSS) is proposed for wideband applications. Firstly, the quantitative relationship between the equivalent impedance of RFSS and the permittivity of the effective media is constructed with the help of the transmission matrix method. The dispersion regulation of permittivity is achieved by changing the pattern and the square resistance of RFSS. In terms of absorber design, a uniform absorber with dispersion manipulation is developed as a precursor absorber. The uniform absorber has an absorption performance better than −8.5 dB above 2 GHz at normal incidence. The loss mechanism is analyzed in detail by electric field distribution and surface power loss density distribution, indicating that the uniform design cannot achieve thickness saving when extending to low frequency. Therefore, a dispersion compensation design absorber is proposed to extend −10 dB bandwidth to 1.64–28.8 GHz. Experiment results agree well with the simulation results, validating the analytic methods and design principles.