Electrical Energy Research Articles

Adaptive Multi-Agent Reinforcement Learning for Optimizing Dynamic Electric Vehicle Charging Networks in Thailand

The rapid growth of electric vehicles (EVs) necessitates efficient management of dynamic EV charging networks to optimize resource utilization and enhance service reliability. This paper explores the application of adaptive multi-agent reinforcement learning (MARL) to address the complexities of EV charging infrastructure in Thailand. By employing MARL, multiple autonomous agents learn to optimize charging strategies based on real-time data by adapting to fluctuating demand and varying electricity prices. Building upon previous research that applied MARL to static network configurations, this study extends the application to dynamic and real-world scenarios, integrating real-time data to refine agent learning processes and also evaluating the effectiveness of adaptive MARL in maximizing rewards and improving operational efficiency compared to traditional methods. Experimental results indicate that MARL-based strategies increased efficiency by 20% and reduced energy costs by 15% relative to conventional algorithms. Key findings demonstrate the potential of extending MARL in transforming EV charging network management, highlighting its benefits for stakeholders, including EV owners, operators, and utility providers. This research contributes insights into advancing electric mobility and energy management in Thailand through innovative AI-driven approaches. The implications of this study include significant improvements in the reliability and cost-effectiveness of EV charging networks, fostering greater adoption of electric vehicles and supporting sustainable energy initiatives. Future research directions include enhancing MARL adaptability and scalability as well as integrating predictive analytics for proactive network optimization and sustainability. These advancements promise to further refine the efficacy of EV charging networks, ensuring that they meet the growing demands of Thailand’s evolving electric mobility landscape.

Electromechanical coupling optimization for a sandwich beam activation using piezoceramics

Sandwich beams composed of two stiff carbon fiber skins and a viscoelastic core are often used to passively dissipate energy through the activation of shearing in a specific frequency range. Semi-active or active energy dissipation can be made possible on those structures adding piezoelectric patches, coupling mechanical vibration energy and electrical energy. J.L. Guyader et al. [jsv, 1978] theorized a frequency dependent equivalent dynamic model of a sandwich structure, recently extended to the homogenization of anisotropic multi-layers by F.Marchetti et al. [jsv, 2020]. This frequency-dependent stiffness of the beam has to be taken into account in the piezoceramic thickness definition in order to optimize the global electromechanical coupling coefficient. An analytical model is derived from the works of F.Marchetti et al. and adapted to predict the first vibration mode of a finite cantilever beam instrumented with a piezoelectric patch. The electromechanical coupling evolution is then calculated with the proper boundary conditions and for different PZT ceramic thicknesses. This model is furtherly used to define the best transducer configuration for a given sandwich structure beam.

Performance investigation on PVT collector with cerium oxide nano fluids

The constant temperature rise on the solar panel surface causes a deterioration of electrical power generation. This article is provided with the performance of photovoltaic thermal (PVT) collector through cerium oxide with water as a base fluid. A small percentage of incoming radiation is transformed into electricity and rest of them is wasted as hot energy, the panel surface temperature will confine the performance of PV module. The research's objectives were to develop and construct a photovoltaic/thermal collector and evaluate its thermal and electrical energy as an output. The experimental investigation of PVT collector with two different concentration of cerium oxide 0.5 and 1.0 LPM (litres per minute). As per the investigations on the PVT collector results were obtained as electrical performance of collector was attained about 18.56 %, 19.12 % for the flow rate of 0.5 and 1.0 LPM. Similarly, thermal performance was achieved 48.38 %, 54.03 % for the flow rate of 0.5 and 1.0 LPM. Thermal conductivity of cerium oxide nano fluid was much better than the air and water. It was observed that employing a nano fluid to the receiver might increase the efficiency around 5–10 %, compared to utilising water as a base fluid, water can only generate 3–7 %. As a cooling medium, air has a relatively low production capacity between 2 and 3 %.

Rainbow trapping and piezoelectric energy harvesting of flexural waves in a gradient metamaterial waveguide

Metamaterials have provided a new way of controlling classic waves to achieve applications in space. In this work, we construct the gradient waveguide in two-dimensional elastic metamaterial plate to achieve rainbow trapping of flexural waves and then realize piezoelectric energy harvesting. Based on the band gap of flexural waves, the waveguide is formed by the introduction of line defects into the perfect metamaterial plate. The gradient waveguide is designed through the investigation of dispersion curves of guided waves for different geometrical parameters. The elastic flexural waves at different frequencies in the gradient waveguide separate, stop and hence are amplified in different positions. That is, the rainbow trapping is observed. To convert mechanical energy into electrical energy, piezoelectric patches are attached in the proposed metamaterial waveguide. Compared with a reference harvester (i.e., a homogeneous plate without metamaterial structure), the output power from the metamaterial energy harvester is significantly amplified. Besides, the proposed metamaterial harvester exhibits the capacity of multi-frequency energy harvesting.

Fundamental study on the difference between materials and vibration conditions in piezoelectric vibration power generation using electromechanical coupling phenomena

Conventionally, vibration energy and sound energy are emitted as noise and vibration. We have proposed a system that converts the vibration of the plate into energy. In this study, a circular plate of constant thickness, on which a piezoelectric element was installed, was adopted as the host structure of an energy-harvesting system. The plate was supported at its elastic end, which was intermediate between simple and clamped supports, and was subjected to a harmonic point force. The piezoelectric performance of the system was highly dependent on the vibration characteristics of the plate. Regarded as one of the representative vibrational characteristics, the natural frequency of the plate was affected by the materials, excitation positions, and vibration modes of the plate. Therefore, the plate materials varied the natural frequency, thus affecting the conversion of vibration energy into electrical energy through the piezoelectric effect. In this study, we investigated plates made of selected materials commonly used in industry and tested different excitation conditions. As the result, we clarified that the proposed system is almost unaffected by the material of the plates, and it was shown to be useful.

R744 Refrigeration Solution for Small Supermarkets

Application based technology solution is nowadays preferred to achieve the performance of the cooling system configuration at its best. Therefore, benchmarking is an essential criterion which would add value to the optimum system design for various applications. In this study, a case study is carried out for a Milk Bar (small supermarket) to evaluate the potential of R744 cooling system for the similar cooling demand and tropical conditions. Field data collected during a particular time and temperature zone is further used to develop a yearly round performance of the HFC plug-in cabinets for MT and LT applications. The data is further used to develop a centralized R744 booster system that would meet the similar cooling load and demand of all the cabinets in the shop. Based on the cooling loads for the HFC unit, the yearly performance of the R774 booster system is calculated and compared to the existing plug-in solution. It is observed that the yearly electric energy consumption for the R744 centralized refrigeration system is 3.3 M W·h, 24% lower than with the existing solution based on HFCs. Moreover, the economic prospective of the R744 is further discussed to alternative material for the components and centralized unit structure which could empower the system with more reliability and an effective substitute to the synthetic technology for smaller supermarkets.

Carbon footprint evaluation for electric vehicles considering green electricity trading

Electric vehicles (EVs) are often seen as a symbol of environmental friendliness. However, while EVs themselves do not directly emit carbon, the electricity they rely on may still contribute to carbon emissions. It is challenging to accurately assess the environmental impact of different types of electric energy used in charging stations due to unified pricing transactions. This hinders the precise measurement of each EVs' carbon footprint. To address this issue, this paper proposes a method for evaluating the carbon footprint based on Carbon Emission Flow (CEF) and energy traceability. A carbon integral mechanism is designed based on the China Certified Emission Reduction (CCER) scheme for coupling EVs with green electricity trading. These elements are integrated into the EV carbon footprint evaluation. Furthermore, the EVs' carbon footprint is minimized to select the lowest-carbon charging path for EVs owners. The feasibility of this proposed method is verified using an example from IEEE33 which quantifies EV footprints and indirect carbon emissions within the distribution network, ultimately encouraging consumption of green electricity by EVs and promoting more environmentally friendly modes of travel.

Hydrogen underground storage for grid electricity storage: An optimization study on techno-economic analysis

This study performs a techno-economic analysis of hydrogen underground storage systems for grid electricity storage, evaluating their economic viability at the plant scale using dynamic optimization. It explores the feasibility of various system configurations and revenue models in the context of volatile electricity prices and the necessity for multiple revenue streams. The hypothesis tested is that large-scale hydrogen storage, despite its low round-trip efficiency, can be economically viable with the right mix of revenue streams. This study uses scenario-based analysis to assess the impacts of different system configurations, including engaging in time-shifting arbitrage, ancillary service markets and blending hydrogen with natural gas. Results indicate potential annual net cash flows of up to $1.5 million from ancillary services integration and $5.2 million from natural gas blending, contingent on specific system sizes. The study concludes that hydrogen underground storage for grid electricity storage can be profitable, and emphasizes that proper system design and precise electricity price forecasting are crucial for optimizing system performance and economic returns. This research sets the stage for further investigations into the scalability of hydrogen storage systems and their broader implications for grid electricity storage and energy market dynamics.

Design and stability performance optimization of a novel hybrid inspection robot walking device for smart grid applications

Inspecting in high-altitude windy environments requires maintaining a stable attitude to avoid significant oscillations, which is a crucial factor in advancing the use of hybrid power transmission line inspection robots (PTLIRs) in real-world scenarios for the electrical power and energy industry. We developed and optimized a novel walking device to improve the safety of hybrid PTLIRs operating in strong wind conditions. First, we investigate the operational conditions of transmission line inspection and design a walking device capable of transporting a flight device to be suspended under the line for inspection purposes. Second, a force equilibrium analysis is performed to explore the relationship between the key structural parameters of the walking device and the wind-induced deflection of the robot. A multiobjective optimization model is formulated to minimize the maximum deflection angle of the robot along three axes under wind loads. Finally, an optimization algorithm, using an improved non-dominated sorting particle swarm optimization (NSPSO) approach, is proposed to solve the model with good global search ability and fast convergence speed. A test platform is constructed to collect the wind deflection angle of a self-developed hybrid PTLIR under the transmission line. The test results demonstrate that the walking device can carry 30 kg to move along the transmission line. The average deflection angle of the robot around the Z axis is the highest under the influence of wind force level 7 (wind speed of 15.5 m/s) perpendicular to the windward surface of the robot. After optimization, the maximum deflection angle is limited to 10.38°, aligning within safety thresholds. The optimization algorithm effectively reduces the maximum deflection angles around the X, Z, and Y axes by 33.19 %, 39.21 %, and 13.23 %, with minimal average errors of 2.40 %, 3.87 %, and 2.13 %, respectively. The research in this paper can solve the bottleneck problem of robot practicality, which has important theoretical significance and practical application value for the safety, stability, and intelligent operation and maintenance management of power transmission lines.

Optimizing electrical energy savings by utilizing refrigerant catalysts in compressors

Optimizing electrical energy savings by utilizing refrigerant catalysts in compressors

Hygroscopic Nature of Lithium Ions: A Simple Key to Super Tough Atmosphere-Stable Hydrogel Electrolytes.

Gel electrolytes have emerged as a versatile solution to address numerous limitations associated with liquid electrolytes in electrical energy storage (EES) devices, in terms of safety, flexibility, and affordability. Aqueous gel electrolytes, in particular, exhibit exceptional features by offering one of the highest ion solvation capacities and ionic conductivities. The two main challenges with hydrogel electrolytes are their easy freezing at subzero temperatures and rapid dehydration under open conditions, leading to the failure of the EES device. In response, we present an uncomplicated and quick-to-make hydrogel electrolyte system offering impressive mechanical properties (205.5 kPa tensile strength, 2880 kJ/m3 toughness, and 3030% strain at the break), along with antifreezing and antiflammability attributes. Notably, the hydrogel electrolyte demonstrates high ionic conductivity and superior performance in supercapacitor cells over a wide range of temperatures (-40 to 80 °C) and under various deformations. The hydrogel electrolyte maintains its capabilities under open conditions over an extended period of time, even at 50 °C, showcased by powering a wristwatch. The atmospheric stability of the hydrogel electrolyte demonstrated in this study introduces promising prospects for the future of EES devices spanning from production to end-user consumption.

A Thermodynamic Comparison of Exergy Production from Sugarcane and Photovoltaic Modules in the Context of Brazilian Energy Transition

This article applies the exergy analysis to the production and use of sugarcane, considering a model published in the literature. In this way, we compute incident solar irradiation, carbohydrate production, water consumption, and the production of stalks and straws. Following the production estimate, we analyze a biorefinery production cycle, from solar irradiation to the biorefinery products on an exergy basis, from birth to production of sugar, electrical energy, and ethanol. The calculated sugarcane production values are 80.7 tons per hectare for a 52-week cycle. As a result, the average exergy efficiency of sugarcane is 4.99%, reaching peaks of 8.3%. When considering only the useful exergy generated in the production of stalks and straw, an annual yield of 17.86 kWh/m2 represents an overall exergy efficiency of 1.31%. Considering the energy conversion processes in the biorefinery, the exergy efficiency from the radiation to the products from the biorefinery was 0.38%. The photovoltaic modules already have a well-established application in the country, though they need to increase their insertion over time, whereby the panels exhibit an average exergy efficiency of 31.6%, resulting in an annual electrical energy production of 255.84 kWh/m2. The results show that photovoltaic modules are a more efficient alternative than sugarcane regarding exergy land use. In conclusion, this study briefly discusses the use of sugarcane and photovoltaic modules in the context of Brazil’s energy transition towards a reduced dependence on fossil fuels, based on the fact that sugarcane already has a low carbon footprint for transportation using ethanol, with supply from more than 40,000 stations, and a similar or lower carbon footprint than electrical vehicles used across the country.

A Sustainable Agri-Photovoltaic Greenhouse for Lettuce Production in Qatar

Qatar identified that food supply security, including self-sufficiency in vegetable production and increasing sustainable renewable energy generation, is important for increasing economic and environmental resiliency. Very favorable solar energy resources in Qatar suggest opportunities to simultaneously meet this goal by integrating solar energy generation and food production. This study examines the feasibility of developing a sustainable agri-photovoltaic (APV) greenhouse design. A comprehensive greenhouse with solar energy generation included is developed for year-round operation in Lusail, Qatar. The performance of the system is predicted by integrating meteorological data and MATLAB simulations of system components. Important design considerations included optimizing solar energy generation by fixed solar photovoltaic panels placed on the maximum available surface area of the greenhouse canopy, while balancing crop insolation and energy needs for greenhouse HVAC systems. Electrical energy is also stored in an industrial battery. Results suggest the APV greenhouse is technically and economically viable and that it could provide benefits, including enhancing food security, promoting renewable energy, and contributing to sustainable food and energy production in Qatar.

Molten salt approach of zeolitic imidazole framework derived strontium doped porous carbon based bifunctional electrocatalysts for direct methanol fuel cell

Direct Methanol Fuel Cells (DMFCs) have sparked widespread interest and offer a viable approach for generating power. It has a number of commercial advantages, including low price, compact construction, and a quick refilling process that directly convert the chemical energy of methanol into electrical energy through an electrochemical reaction. However, direct methanol fuel cells (DMFCs) frequently rely on platinum catalysts, which are expensive and limited in scalability. Platinum catalysts can be poisoned by carbon monoxide (CO) thus preventing their widespread commercialization. Due to these drawbacks, there is growing interest in developing catalysts based on non-noble metals to improve DMFC technology's deployment. Herein, we report a facile synthesis method using a molten salt approach, which involves the solvent-free mixing of strontium nitrate tetrahydrate with ZIF-67, followed by direct pyrolysis in an Ar/H2 atmosphere at 800 °C. For methanol oxidation the strontium oxide loaded catalytic materials i.e., CoxOy SrO/C (1:1) exhibited a peak current density of 161 mA/cm2 and stability of 71 % over 28800s and for ORR it exhibit current density of −5.86 mA/cm2 and half wave potential of 0.87 V. The facile MOF synthesis strategy, enhanced by molten salt processing, shows great potential for creating non-noble catalytic materials for high-performance fuel cells.

Thermal management of water electrolysis using membrane distillation to produce pure water for hydrogen production

When electrolysis units are used for water splitting to provide green hydrogen, waste heat must be dissipated to avoid performance degradation. Therefore, the hypothesis was that if a membrane distillation unit could use the waste heat to desalinate the feed water, then the operating costs may be reduced. This study demonstrated the first integration of a 0.03 m2 active area membrane distillation heat exchanger (MDHX) system with a 2.2 kW commercial electrolyser. The MDHX system satisfied the thermal requirements of the electrolysis unit. It was estimated that for a 2GW electrolysis plant, it could result in annual savings of up to $2 million. During operation with the 2.2 kW electrolyser, the MDHX unit was able to produce 50 % of the permeate rate required to match the water consumption of the electrolyser. Experimentally the MDHX system operated with a specific electrical energy consumption of 230 kWh/m3. Design changes such as improving pump efficiency and optimising flow field geometry to allow for lower flow rates, suggest there is scope for reduction in energy consumption. Indeed, further development of the MDHX technology is necessary before it can compete with large-scale seawater reverse osmosis (SWRO) methods.

Efficient utilization of abandoned mines for isobaric compressed air energy storage

There are massive abandoned coalmines and corresponding underground space, which provides a viable solution to energy storage of renewable energy generation. Here a novel scheme of isobaric compressed air energy storage (CAES) is proposed to improve the performance of energy storage in underground space. Energy recovery efficiency and energy storage density of isobaric CAES are respectively 70.60% and 5.74 kWh/m3, while they are 70.56%, 1.14 kWh/m3 and 60.19%, 2.46 kWh/m3 respectively for pumped hydro storage and isochoric CAES. Abandoned mining fields can install photovoltaic and wind power, while underground tunnels can storage energy, transforming abandoned mines into a renewable energy support base with electricity generation and storage integrated into a site. Electrical energy with low frequency and high frequency in the base can all be used by driving compressors and heaters respectively. Besides, isobaric CAES can provide space heating and cooling simultaneously through using interstage compression heat and expanding refrigeration technique.

Body heat energy driven knitted thermoelectric garments with personal cooling

Wearable, thermoelectric (TE) devices have gained significant interest in recent years as they can both generate output power from converting body heat into electrical energy and be utilized in personal cooling through the Peltier effect. Currently, researched wearable TE cooling devices focus on devices that can be attached to the human body in specific locations and use heat sinks or elongated thermoelectric pillars to increase their effectiveness, making them hard and bulky. In addition, these devices are attached, not integrated, to wearable garments, making their manufacturing a multi-step process. To address this issue, we developed a knitted TE garment through a single-step manufacturing process that offers energy generation and personal cooling capabilities. The functioning of the cooling device was mathematically modelled and analyzed to understand its scalability, optimization, and to show its potential. This garment features excellent thermoelectric generation of 7.48 mV and 0.46 mA on the human body, and the ability to cool the human body up to 1.5 °C. The observations proved that the mathematical model could predict the behavior of the TE device closely. The results showed that the proposed method of knitted TE cooling garment manufacturing is a viable and scalable process.

Large-scale energy storage for carbon neutrality: thermal energy storage for electrical vehicles

AbstractThermal Energy Storage (TES) systems are pivotal in advancing net-zero energy transitions, particularly in the energy sector, which is a major contributor to climate change due to carbon emissions. In electrical vehicles (EVs), TES systems enhance battery performance and regulate cabin temperatures, thus improving energy efficiency and extending vehicle range. The enhanced efficiency reduces overall energy consumption in EVs. Consequently, this reduction in energy demand can lead to decreased infrastructure needs, minimising the scale and investment required in energy production and distribution systems. Furthermore, the integration of TES with existing infrastructure allows for the simultaneous charging of thermal and electrical energy, leveraging waste heat or renewable energy sources. This not only cuts costs by optimizing resource use but also bolsters sustainability by minimising reliance on non-renewable energy sources. The widespread adoption of TES in EVs could transform these vehicles into nodes within large-scale, distributed energy storage systems, thus supporting smart grid operations and enhancing energy security. Strategic investments and regulatory updates are essential to realise a sustainable, carbon-neutral transportation future, underpinned by robust, cost-efficient infrastructure.

Implementation of a Low-Cost Current Perturbation-Based Improved PO MPPT Approach Using Arduino Board for Photovoltaic Systems

In photovoltaic (PV) systems, the conversion of solar energy into electrical energy by the PV module is influenced by various factors, including sunlight intensity and temperature. To achieve optimal performance, it is crucial to accurately track the maximum power point (MPP) of the PV module. Among the numerous MPP tracking (MPPT) techniques that have been developed, the perturbation and observation (PO) method has gained significant attention due to its simplicity and reliability. However, the fixed perturbation step size used in the traditional PO algorithm can result in poor tracking capability, excessive ripple, and drift, leading to high power loss and low tracking efficiency. To address these limitations, this paper proposes an improved version of the PO strategy that introduces an adaptable step-magnitude mechanism, utilizing current perturbation instead of the voltage perturbation typically employed in the classical PO method. This enhanced indirect PO approach maintains low complexity and can be easily implemented on a cost-effective Arduino Uno board. A streamlined C++ code integrates the improved PO MPPT strategy with a Proportional Integral Derivative (PID) controller, eliminating the need for separate PID blocks and further reducing system complexity. To evaluate the effectiveness of the proposed technique, comparative analyses are conducted against the traditional PO algorithm, particle swarm optimization (PSO), fuzzy logic control (FLC), and a recently introduced approach, the zone voltage (ZV) method. Simulation results using Proteus software demonstrate that the improved PO approach outperforms the other techniques in various aspects, including achieving the highest static and dynamic tracking efficiencies of 99.38% and 99.88%, respectively, negligible power loss and fluctuations, the fastest convergence speed, and the shortest tracking time of 0.19 seconds.

Three-dimensional porous SiC/BDD electrode with long-term robustness and enhanced electrochemical degradation performance for refractory organic pollutants

Boron-doped diamond (BDD) electrodes with a three-dimensional (3D) porous network structure can overcome the mass transfer limitations and increase substantially the utilization rate of active oxygen species. Nonetheless, the 3D porous network structure was invariably built using metallic substrates, which inherently have inferior stability because of their non-corrosion resistance and the severe thermal mismatch between BDD films and substrates. Herein, we reported, for the first time, the use of a commercially porous silicon carbide (SiC) as the substrate to construct a 3D SiC/BDD electrode to simultaneously alleviate the problematics of substrate corrosion and thermal mismatch. This novel electrode exhibited a long-term service lifetime of 800 h in 3 M H2SO4 under the current density of 50 mA cm−2, over 500 times longer than the conventional metallic substrate-based BDD electrodes. The optimum p-SiC/BDD electrode exhibited a high oxygen evolution potential of 2.04 V vs. SHE, a low charge transfer resistance of 18.4 Ω, a high mass transfer coefficient of 2.78 × 10−5 m s−1, and a thin diffusion layer thickness of 25.2 μm. The proposed electrode had a threefold larger pseudo-first-order reaction rate constant than a flat BDD electrode, although it consumed just a fourth of the latter’s electric energy. The superior performance was attributable to an increased mass transfer rate confirmed by computational fluid dynamics (CFD) simulations as well as a high yield of reactive oxygen species verified by electron spin resonance (ESR). Furthermore, the proposed SiC/BDD electrode could work effectively under different water matrices in the presence of diverse salt electrolytes, thus paving a new avenue for the structure design of robust non-active anode materials.