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This article introduces a novel regenerative suspension system designed for active seat suspension, to reduce vibrations while recovering energy. The system employs a four-quadrant electric actuator operation model and utilizes a brushless DC motor as an actuator and an energy harvester. This motor, a permanent magnet synchronous type, transforms DC into three-phase AC power, serving dual purposes of vibration energy recovery and active power generation. The system's advanced vibration control is achieved through the switching of MOSFET transistors, ensuring the suspension system meets operational criteria that contrast with traditional vibro-isolation systems, thereby reducing the negative effects of mechanical vibrations on the human body, while also lowering energy consumption. Comparative studies of the regenerative system dynamics against passive and active systems under random vibrations demonstrated its effectiveness. This research assessed the system's performance through power spectral density and transmissibility functions, highlighting its potential to enhance energy efficiency and the psychophysical well-being of individuals subjected to mechanical vibrations. The effectiveness of the energy regeneration process under the chosen early excitation vibrations was investigated. Measurements of the motor torque in the active mode and during regenerative braking mode, and the corresponding phase currents of the motor, are presented. [ABSTRACT FROM AUTHOR]

Over the past decade, various researchers have shown the practicality of extracting electrical energy from vibrating structures. The primary objective of this research was to optimize the parameters of a basic cantilever harvester to maximize the energy production of electricity from surrounding mechanical energy. A distributed parameter model and its modal solution were utilized to determine the design variables via a parametric investigation. It is important to ensure sufficient power generation when there is a wide range of frequencies being excited, without any specific frequency being emphasized. The cost function for the optimization problem was defined as the average power within a specific frequency range, considering geometric and physical restrictions. It was discovered that different parameters' values can be utilized to generate varying maximum power levels for different frequency ranges. Furthermore, a comparative analysis was performed between the finite element method (FEM) using ANSYS and the current harvesting model. The comparison demonstrated a high level of concordance, enabling the utilization of the finite element method (FEM) for subsequent investigation. [ABSTRACT FROM AUTHOR]

Electrical devices are integral to daily life, but limited battery life remains a significant issue. A proposed solution is to convert dissipated energy from human motion into electricity using piezoelectric materials. This study investigates lead–zirconate–titanate (PZT) piezoelectric materials in bimorph configuration, conducts performance tests to understand their characteristics and determine the optimal load resistance, and develops an energy-harvesting prototype. Performance tests adjusted input parameters and varied load resistance and input magnitude to optimize power gained from the PZT bimorph. A suitable human movement for the application of the bimorph is a mouse-clicking motion by fingers. A prototype was created by integrating the bimorph into a computer mouse to capture energy from clicks. The results showed that the deformation rate of the PZTs, input magnitude, and resistance load were key factors in optimization. The bimorph configuration produced 0.34 mW of power and 5.5 V at an optimum load of 5072 Ω, requiring less effort to generate electricity. For the computer mouse energy harvester case, it yielded a total average power of approximately 38.4 μW per click with a click frequency of 4 Hz. This power could be used to support IoT devices such as human sensors (e.g., CO2, temperature, and pulse sensors) and smart home sensors, enabling comprehensive health and environmental monitoring. In conclusion, input specifications, magnitude, and load resistance are essential for optimizing piezoelectric energy harvesters. [ABSTRACT FROM AUTHOR]

The increasing need for wearable and portable electronics and the necessity to provide a continuous power supply to these electronics have shifted the focus of scientists toward harvesting energy from ambient sources. Harvesting energy from ambient sources, including solar, wind, and mechanical energies, is a solution to meet rising energy demands. Furthermore, adopting lightweight power source technologies is becoming more decisive in choosing renewable energy technologies to power novel electronic devices. In this regard, piezoelectric nanogenerators (PENGs) based on polymer composites that can convert discrete and low-frequency irregular mechanical energy from their surrounding environment into electricity have attracted keen attention and made considerable progress. This review highlights the latest advancements in this technology. First, the working mechanism of piezoelectricity and the different piezoelectric materials will be detailed. In particular, the focus will be on polymer composites filled with lead-free BaTiO3 piezoceramics to provide environmentally friendly technology. The next section will discuss the strategies adopted to enhance the performance of BaTiO3-based polymer composites. Finally, the potential applications of the developed PENGs will be presented, and the novel trends in the direction of the improvement of PENGs will be detailed. [ABSTRACT FROM AUTHOR]

Energy harvesting from energy sources is a rapidly developing cost-effective and sustainable technique for powering low-energy consumption devices such as wireless sensor networks, RFID, IoT devices, and wearable electronics. Although these devices consume very low average power, they require peak power bursts during the collection and transmission of data. These requirements are satisfied by the use of energy-storage devices such as batteries or supercapacitors (SCs). Batteries offer significantly higher energy density but are subject to regular replacement, thermal runaway risk, and environmental concerns. On the other hand, SCs provide over a million-fold increase in capacitance compared to a traditional capacitor of the same volume. They are considered as the energy-storing devices that bridge the gap between conventional capacitors and batteries. They also offer fast charging times, a long lifecycle, and low equivalent series resistance (ESR). Most importantly, they are capable of handling the high transient currents produced by energy harvesters and provide a stable power source for external loads. This study encompasses a brief exploration of the three fundamental SC types. Then, the discussion delves into the integration of SCs into energy harvesting applications. The collective knowledge presented aims to guide future research endeavors fostering the development of novel energy harvesting systems using SCs. [ABSTRACT FROM AUTHOR]

The need to globalize and implement the fourth industrial revolution has led to increased interest in research on renewable energy harvesting equipment. Wind and solar have been the fastest growing sources of energy and have been used to reduce our dependency on fossil fuels for energy. The Savonius wind turbine is an attractive option for regions with high turbulence intensity and low wind speeds due to its advantages over other small-scale vertical-axis wind turbines. These advantages include its simple design, satisfactory performance at lower speeds, and ability to turn independent of the wind flow direction. However, Savonius wind turbines face several challenges. The most significant one being the negative torque generated during operation. This negative torque is caused by the interaction between the exhaust air and the returning blade, thus reducing efficiency, as the turbine has to overcome this additional force. To improve on the efficiency, various assessments and optimization techniques have been employed. These focus on the geometric parameters of the Savonius wind turbine as well as installation augmentation techniques. This article reviews and reports on several combinations of parametric performance-influencing adjustments and power augmentation techniques applied to Savonius wind turbines. The article concludes by proposing future research directions. [ABSTRACT FROM AUTHOR]

This study primarily investigates the adaptability and performance of hydraulic–electric regenerative dampers for high-speed trains by substituting conventional primary dampers with hydraulic–electric regenerative dampers. The primary objectives are to develop a detailed model of primary suspension regenerative damper (PSRD) energy conversion that incorporates factors such as oil pressure loss, motor efficiency, and overall system efficiency, and to perform a comprehensive comparative analysis of vibration responses, wheel wear, comfort indices, and power generation using an integrated MATLAB and SIMPACK co-simulation platform. The results reveal that at an operational speed of 350 km/h, the dynamic responses of the carbody, bogie, wheelset, and dampers equipped with the proposed PSRD systems closely align with those of conventional primary vertical damper systems. The detailed PSRDs' hydraulic–mechanical–electrical model effectively captures the subtleties of oil pressure fluctuations and their impacts. The wear distribution and magnitude across the vehicle remain consistent during acceleration, constant, and deceleration speeds, ensuring uniform wear characteristics. Under real-world railway operational conditions, the ride comfort metrics of vehicles fitted with regenerative dampers are comparable to those with conventional primary vertical dampers. Furthermore, each regenerative damper can generate up to 21.72 W of electrical power, achieving a generation efficiency of 45.28%. Finally, a test rig was designed and fabricated to validate the primary suspension regenerative damper (PSRD) model, showing good agreement between predicted and actual damping force and power regeneration, with results indicating a peak damping force of 12.5 kN and approximately 230 W of regenerated power. This research provides a theoretical foundation and experimental validation for implementing power regeneration mechanisms in railway transportation, demonstrating that the hydraulic–mechanical–electrical PSRD model can fulfil the performance criteria of conventional dampers while offering substantial energy harvesting capabilities. This advancement not only enhances energy efficiency but also contributes to the sustainable development of high-speed rail systems. [ABSTRACT FROM AUTHOR]

The ability to power low-power devices and sensors has drawn a great deal of interest to energy harvesting from ambient vibrations. The application of variable-length pendulum systems in conjunction with piezoelectric or electromagnetic energy-harvesting devices is examined in this thorough analysis. Because of their changeable length, such pendulums may effectively convert mechanical vibrations into electrical energy. This study covers these energy-harvesting systems' basic theories, design concerns, modeling methods, and performance optimization strategies. This article reviews several studies that look at dynamic models, the effects of damping coefficients, device designs, and excitation parameters on energy output. The advantages and disadvantages of piezoelectric and electromagnetic coupling techniques are demonstrated by comparative research. This review also looks at technical advances and future research prospects in variable-length, pendulum-based energy harvesting. An expanded model for an energy harvester based on a variable-length pendulum derived from the modified, swinging Atwood machine is more specifically presented. This model's numerical simulations, estimated current and voltage outputs, and produced power from the electromagnetic and piezoelectric devices integrated at various points in a 4-DOF variable-length pendulum model all indicate encouraging results. This necessitates extra study, changes, and optimizations to improve the usefulness of the proposed model. Finally, important dynamic models on developing variable-length, pendulum-based energy harvesters for usage in a range of applications to create sustainable energy are summarized. [ABSTRACT FROM AUTHOR]

The present paper is concerned with a magnetorheological (MR)-damper-based vibration-reduction system with energy harvesting capability considering sprung mass changes. The system represents a mechanical harmonic oscillator with electrical coupling, set in motion by kinematic excitation. The authors examine the system performance in the case when the MR damper control coil (damper control coil) is powered directly by the alternating current resulting from the voltage generated in an electromagnetic harvester in the assumed frequency range of sine excitation. Such a system is able to attenuate vibration in the near-resonance frequency range when the current in the damper control coil increases; however, its drawback is vibration amplification at higher frequencies. To eliminate this negative feature, it is proposed to connect shunt capacitors in parallel with the damper control coil. Then, the system can be tested experimentally in terms of current in the damper control coil, sprung mass, and the capacity of shunt capacitors in order to evaluate system performance according to the assumed performance index. The obtained results demonstrate significant improvement in system performance at higher frequencies of excitation. [ABSTRACT FROM AUTHOR]

This paper presents the design and performance of an energy subsystem (ES) dedicated to hybrid energy harvesters (HEHs): wave energy converters (WECs) combined with photovoltaic panels (PVPs). The considered ES is intended for compact HEHs powering autonomous end-node devices in distributed IoT networks. The designed ES was tested experimentally and evaluated in relation to the mobile and wireless distributed communication use case. The numerical evaluation was based on the balance of the harvested energy versus the energy consumed in the considered use case. The evaluation results proved that the ES ensured energy surplus over the considered IoT node consumption. It confirmed the proposed solution as convenient to the compact HEHs applied for sustainable IoT devices to power them with renewable energy harvested from light and sea waves. It was found that the proposed ES can provide the energy autonomy of the IoT end node and increase its reliability through a hybrid energy-harvesting approach. [ABSTRACT FROM AUTHOR]

Wind turbines are a solution for sustainable energy, significantly reducing carbon emissions and fostering a circular economy for more cost-effective and cleaner power generation, in line with worldwide environmental aspirations. In this context, this research aims to explore a novel two-stage, twisted-blade micro-Vertical-Axis Wind Turbine (μ -VAWT)alternative inspired by the Savonius Rotor (SR). This investigation utilizes the κ − ω SST turbulence model to explore the power coefficient ( C P ) and torque coefficient ( C T ), finding C P values ranging from 0.02 to 0.08 across the turbine by altering the free stream velocity (V). C T analysis further delves into four specific sections, highlighting areas of particular interest. These results are validated by examining velocity contours, pressure contours, and streamlines in four horizontal sections, demonstrating that the proposed turbine model exhibits minimal torque fluctuation. Moreover, the analysis of vertical wind streamlines illustrates very low interference with various wind turbine proposals, underscoring the turbine's efficiency and potential for integration into diverse wind energy projects. [ABSTRACT FROM AUTHOR]

A lack of natural resources drives the oil dependency in Pacific Island Countries and Territories (PICTs), hampering energy security and imposing high electricity tariffs in the region. Nevertheless, the Western Equatorial Pacific is known for its large Sea Surface Temperature (SST) and deep-sea water (DSW) temperature difference favorable for harvesting thermal energy. In this study, we selected 18 PICTs in the western Equatorial Pacific to estimate Annual Energy Production (AEP) for a 1 MW class Ocean Thermal Energy Conversion (OTEC) plant. We combined the DSW temperature from the mean in situ Argo profiles and 1 km resolution satellite SST data to estimate the thermal energy resource resolving the fine features of the island coastline. Furthermore, the twenty-year-long SST dataset was used to analyze the SST variability. The analysis showed that Equatorial islands and Southern islands have the highest inter-annual variability due to El Nino Southern Oscillation (ENSO). The power density varied from 0.26 to 0.32 W/m2 among the islands, with the lowest values found for the southernmost islands near the South Equatorial Countercurrent. Islands within the South Equatorial Current, Equatorial Undercurrent, and North Equatorial Countercurrent showed the highest values for both power density and gross power. Considering a 1 MW class OTEC plant, Annual Energy Production (AEP) in 2022 varied from 7 GWh to 8 GWh, with relatively low variability among islands near the Equator and in low latitudes. Considering the three variables, AEP, SST variability, and distance from the shore, Nauru is a potential candidate for OTEC, with a net power of 1.14 MW within 1 km from the shore. [ABSTRACT FROM AUTHOR]

Pavement photovoltaic (PV) is an innovative energy-harvesting technology that seamlessly integrates into road surfaces, merging established PV power generation methods with conventional roadway infrastructure. This fusion optimally utilizes the extensive spatial assets inherent in road networks. This paper offers an exhaustive examination of the literature concerning the physical models and performance evaluation of photovoltaic pavements. This study delineates the essential three-tier structure of pavement modules and juxtaposes the advantages and drawbacks of design models across these strata, thereby facilitating the development of more suitable solutions for varying application scenarios. The importance of accommodating fluctuations in shadows and countering the heat island effect (HIE) is emphasized. Nevertheless, the technology remains in its nascent research phase, characterized by challenges associated with limited long-term durability and efficacy. Building upon these findings, this study addresses the challenges confronting pavement PV from three perspectives and outlines future prospects and recommendations for its progression. [ABSTRACT FROM AUTHOR]

Biomass combustors provide space heating by converting chemical energy in woody biomass into low-temperature thermal energy. Thermoelectric generators (TEGs) can generate electricity from the heat flux without significantly reducing heating performance. However, most current TEGs are small (40 mm × 40 mm), requiring many TEG elements to generate useful power from a biomass combustion-based space heater. This work compares the electrical generation potential of an array of small TEGs with a larger (80 mm × 120 mm) TEG in a vertical configuration representative of a residential heating appliance. An experimental facility was developed for various representative cold-side ducts and controllable hot-side temperature and cooling airflows, and the Taguchi method was used to evaluate the impacts of temperature, airspeed, and ducting configurations. The results indicate that temperature and airspeed significantly influence TEG power, while ducting configurations have an insignificant influence. The large TEG achieved more consistent temperatures but produced lower power than an array of smaller TEGs with the same total area. The study emphasizes optimizing TEG design and operating conditions to enhance electricity generation efficiency in space heating combustors. [ABSTRACT FROM AUTHOR]

This study proposes a hybrid pitching motion for oscillating flat plates aimed at augmenting the energy extraction efficiency of an energy harvester. The proposed hybrid pitching motion, within the first half cycle, integrates a non-sinusoidal movement starting at t/T = 0 and progressing to t/T = 0.25, with a sinusoidal movement initiating after t/T > 0.25 and continuing to t/T = 0.5. The second half of the cycle is symmetric to the first half but in the opposite direction. The calculated results show that the proposed hybrid pitching motion outperforms both the sinusoidal and the non-sinusoidal motions. The hybrid pitching motion merges the merits of both the sinusoidal and non-sinusoidal motions to optimize pitch angle variation. This integration is pivotal for enhancing the overall power output performance of an oscillating energy harvester characterized by momentum change that enhances the orientation of the heaving movement, smoother motion transitions, and consistent energy harvesting. The power generation is obtained at wing pitch angles of 55°, 65°, 70°, 75°, and 80° during a hybrid pitching motion. The proposed hybrid pitching motion, set at a pitch angle of 70°, achieves a maximum power output that exceeds the oscillating flat plate using a sinusoidal pitching motion by 16.0% at the same angle. [ABSTRACT FROM AUTHOR]

Human footsteps are a sustainable energy source that is derived from kinetic energy. As a result, in this study, piezoelectric sensors placed beneath floor tiles were excited by human footsteps to provide practical electrical energy. A simple rectifying circuit with a filter was used to capture electrical power. The floor tile is 455 mm in length and 405 mm in width. Two light-emitted diodes were lit up as the actual load by utilising electrical energy obtained from the kinetic energy generated by human footsteps. The greatest attainable power that could be extracted from the suggested floor tile was 249.6 milliwatts, with an approximate cost of $10.2. [ABSTRACT FROM AUTHOR]

This paper proposes an asymmetric hybrid tri-stable piezoelectric energy harvester for rotational motion (RHTPEH). The device features an asymmetric tri-stable piezoelectric cantilever beam positioned at the edge of a rotating disk. This beam is uniquely configured with an asymmetric arrangement of magnets. Additionally, an elastic amplifier composed of a vertical and a rotating spring connects the beam's fixed end and the disk. This setup enhances both the rotational amplitude and vertical displacement of the beam during motion. A comprehensive dynamical model of the RHTPEH was developed using Lagrange's equations. This model facilitated an in-depth analysis of the system's behavior under various conditions, focusing on the influence of key parameters such as the asymmetry in the potential well, the stiffness ratio of the amplifier springs, the radius of the disk, and the disk's rotational speed on the nonlinear dynamic response of the system. The results show that the asymmetric hybrid tri-stable piezoelectric energy harvester makes it easier to harvest the vibration energy in rotational motion and has excellent power output performance compared with the symmetric tri-stable piezoelectric energy harvester. The output power magnitude of the system at higher rotational speeds increases as the radius of rotation expands, but when the rotational speed is low, the steady-state output power magnitude of the system is not sensitive to changes in the radius of rotation. Theoretical analysis and numerical simulations validate the effectiveness of the proposed asymmetric RHTPEH for energy harvesting in low-frequency rotating environments. [ABSTRACT FROM AUTHOR]

The impact of shading has been a prominent subject of discourse within the realm of photovoltaic (PV) energy harvesting and is recognized as a significant detriment to the system's overall efficiency. Nevertheless, prevailing investigations, which predominantly focus on the hard shading originating from building structures and vegetation, singularly address the umbra shadow phenomenon while overlooking the complexity of shadow properties and their varying intensities. In this context, this present research aims to analyze the impact of shading caused by thin objects, wherein shadow formation deviates from a singular-intensity umbra to a blend of umbra and penumbra, exhibiting diverse intensities. In the initial experimental approach, outdoor trials produced statistically significant findings, identifying both the distance and thickness of shading objects as primary determinants influencing the impact of thin object shading on the power output of PV systems. Furthermore, the analysis of the results revealed that under the specified parameters and assumptions, when considering a thin object with a thickness-to-distance ratio of 2.3 mm/225 cm, the resulting power loss of 1.65% is statistically insignificant. Remarkably, laboratory investigations unveiled a notable correlation between penumbra and power loss, contrasting with outdoor experimentation results. The findings highlight the distinction between indoor and outdoor methodologies, stemming from discrepancies in shadow formation characteristics, thereby emphasizing the necessity of acknowledging and comprehending these variations. [ABSTRACT FROM AUTHOR]

This paper presents a study about the integration of Piezoelectric Energy Harvesting Systems (PE-EHSs) into building envelopes for powering Fiber Bragg Grating (FBG) sensors, enabling efficient and low-consumption monitoring with the objective of leveraging structural health monitoring (SHM). The research includes preliminary tests conducted in a real environment to validate the PE-EHS when fully integrated into a ventilated façade, capturing mechanical vibrations generated mainly by wind loads. Based on these activities, the final configuration of PE-EHSs is defined to provide a complete system for façade monitoring. This integrated system includes the piezoelectric generator (PEG), supercapacitor (SC), Power Conditioner Circuit (PCC), Fiber Optic Sensing (FOS) interrogator, and the IoT gateway transmitting measurement data within an Internet of Things (IoT) monitoring platform. This configuration is tailored to address the challenges related to the structural integrity of building envelopes. Results demonstrate a potential for a stand-alone solution in the façade sector but raise issues for certain limitations, requiring further investigation. In particular, the study emphasizes constraints related to the energy production of PE-EHSs for façade integration. It highlights the necessity to carefully consider these limitations within the broader context of their applicability, providing insights for the informed deployment of piezoelectric energy harvesting technology in building envelope monitoring. [ABSTRACT FROM AUTHOR]

A micro-photosynthetic power cell (µPSC) generates electricity through the exploitation of living photosynthetic organisms through the principles of photosynthesis and respiration. Modeling such systems will enhance insights into the µPSC that can be employed to design real-time applications from µPSC. In this study, the bio-inspired electrical equivalent modeling of the array of µPSC is elucidated. The model is validated for array configurations of the micro-photosynthetic power cells. The developed arrayed model foresees the steady-state response at various electrical loadings. The polarization characteristics of the current-voltage (I-V) and current-power (I-P) characteristics of the array of µPSC in series and parallel, and their combinations in series and parallel connected µPSCs were validated with the experimental results. From this analysis, it is predicted that the arraying of the µPSC in the combination of series and parallel is the optimal array strategy to obtain the desired voltage and current from the µPSC such that it can be used to power real-time low and ultra-low power devices. [ABSTRACT FROM AUTHOR]

This paper provides a proof of concept for a linear electric generator that can be used to harvest energy from various sources of linear motion, such as vibrations, free-piston engines and wave energy. The generator can be used to power small electronic devices, such as sensors, or charge household batteries. The literature was reviewed to develop an understanding about the applications, control methods, excitation methods and mechanics of rotating and linear electric machines. A bidirectional, two-sided linear machine was designed with two stator cores and a single mover core. The stator windings and mover winding can be independently excited, allowing for three modes: no mover excitation, a DC excited mover, and an AC excited mover. Simulation results showed that the magnetic flux generated by DC excited stator cores were concentrated in the centre of the mover core. The use of two stator cores eliminates lateral flux in the mover core when it is not excited, minimising attraction and repulsion forces. Parametric analysis showed that flux cutting occurred in all operation modes, verifying that the generator will produce power when operating. Hardware tests produced an output current when the machine was electrically and mechanically excited, verifying the proposed design. [ABSTRACT FROM AUTHOR]

This document provides an overview of innovations in thermoelectric technology, with a focus on materials and applications. It discusses thermoelectric generators (TEGs), which convert thermal energy into electrical energy, and their versatility in various settings such as space, medical applications, and vehicles. The document also highlights advancements in thermoelectric materials, such as Cu2−xSe and PbTe0.7S0.3, which improve the efficiency of TEGs. The included research papers cover topics such as TEG design, durability under different conditions, and the development of nanostructured materials. The findings emphasize the need for further research and collaboration to enhance the efficiency and practicality of thermoelectric systems. [Extracted from the article]

In the majority of Internet of Things (IoT) applications, persistent and stable operation is a crucial requirement. While environmental energy-harvesting technologies can enhance IoT's persistence, they do not guarantee stability. Therefore, we aim to address the stability challenges in solar-powered IoT (SP-IoT) by employing wireless power transmission (WPT) through unmanned aerial vehicles (UAVs). This study focuses on determining the optimal charging mobility of drones for WPT to enhance the stability of nodes operating in a wide area network (WAN)-based SP-IoT environment. The proposed scheme identifies nodes with insufficient solar energy harvesting and defines the optimal charging mobility parameters (hovering position, hovering time, and moving path) to efficiently transmit the drone's energy to these nodes in a balanced manner. The experimental results confirm that the proposed scheme significantly improves the stability of solar-powered IoT nodes by optimally utilizing the limited energy of the drone. [ABSTRACT FROM AUTHOR]

This paper proposes a novel hybrid marine renewable energy-harvesting system to increase energy production, reduce levelized costs of energy and promote renewable marine energy. Firstly, various marine renewable energy resources and state-of-art technologies for energy exploitation and storage were reviewed. The site selection criteria for each energy-harvesting approach were identified, and a scoring matrix for site selection was proposed to screen suitable locations for the hybrid system. The Triton Knoll wind farm was used to demonstrate the effectiveness of the scoring matrix. An integrated energy system was designed, and FE modeling was performed to assess the effects of additional energy devices on the structural stability of the main wind turbine structure. It has been proven that the additional energy structures have a negligible influence on foundation/structure deflection (<1%) and increased system natural frequency by 6%; thus, they have a minimum influence on the original wind system but increased energy yield. [ABSTRACT FROM AUTHOR]

This article presents research on the usefulness of three different electric circuit simulation environments for exploring energy harvesting from electromagnetic waves using energy harvesters. The software that is compared includes KiCad EDA, LT Spice and MATLAB Simscape Electrical.Too prepare a common background for the results comparison, crucial equations that combine RF transmission with energy are presented. Commercially available harvesters are also presented. An overview of the state-of-the-art research on this topic is summarised. In order to verify software using conditions that are similar to real ones, the power available at the 868 MHZ ISM band, which is close to the LTE bands used for telecommunications, is calculated. The results obtained using different software are close to being identical for all tested simulation environments. [ABSTRACT FROM AUTHOR]

Energy transformation requires replacing power plants based on fossil raw materials with renewable energy. Energy harvesting plays an important, although not fully appreciated, role here. Distributed, local power supply systems for small receivers, based on various sources which previously dissipated energy, may contribute to changing the current energy paradigm. This article presents an overview of energy harvesting technologies and various energy sources used in this process. Particular attention was paid to sources of a less conventional nature. The aim of this article is to encourage and direct scientists with the potential to explore this topic to look for new, previously unexploited energy sources and innovative and effective methods of obtaining useful energy in the harvesting process. [ABSTRACT FROM AUTHOR]

Galloping-based piezoelectric energy harvesting systems are being used to supply renewable electricity for low-power wireless sensor network nodes. In this paper, a W-shaped bluff body is proposed as the core component of a piezoelectric wind energy harvester. Experiments and simulations have shown that the W-shaped bluff body can improve harvesting efficiency at low wind speeds. For the W-shaped structure, the finite element simulation results indicate that the structure can help improve the aerodynamic performance to obtain high aerodynamic force. The experimental results demonstrate that compared with the traditional bluff bodies, the piezoelectric wind energy harvester with the W-shaped bluff body (WEHW) can generate higher output voltages and has a lower cut-in speed. When the length L is 30 mm and the rear groove angle β is 30°, the W-shaped structure can induce the best harvesting performance. When an external load resistance of 820 KΩ is connected and the wind speed is 5 m/s, the WEHW generates an average output power of 0.28 mW. [ABSTRACT FROM AUTHOR]

This paper performs a comprehensive analysis of the wind energy potential of onshore regions in Greece with emphasis on quantifying the volume risk and the spatial covariance structure. Optimization techniques are employed to derive efficient wind capacity allocation plans (also known as generation portfolios) incorporating different yield aspirations. The generation profile of minimum variance and other optimal portfolios along the efficient frontier are subject to rigorous evaluation using a fusion of descriptive and statistical methods. In particular, principal component analysis is employed to estimate factor models and investigate the spatiotemporal properties of wind power generation, providing valuable insights into the persistence of volume risk. The overarching goal of the study is to employ a set of statistical and mathematical programming tools guiding investors, aggregators and policy makers in their selection of wind energy generating assets. The findings of this research challenge the effectiveness of current policies and industry practices, offering a new perspective on wind energy harvesting with a focus on the management of volume risk. [ABSTRACT FROM AUTHOR]

The current investigation provides information about solar updraft tower power plants, SUTPPs (also called solar chimney power plants, SCPPs), which form a unique method of solar-powered electricity production through a ducted wind turbine driven by induced airflow as a result of solar heating. The investigation is conducted using numerical modeling via the system-level simulation tool Aladdin (developed and released freely by the Institute for Future Intelligence, IFI) for solar energy systems, wind energy systems, or the built environment. The Aladdin energy simulator is first evaluated here by comparison with published experimental and numerical results corresponding to the historical 50 kW prototype SUTPP that was successfully tested in Manzanares (Spain) between 1982 and 1989. This prototype has a height of about 195 m for the chimney (the updraft tower) and a radius of about 122 m for the solar heat absorber (the solar air collector or the greenhouse). Next, various climate and performance characteristics are investigated and contrasted for nine different locations around the world with a similar latitude of 24°, which is within the sunbelt, assuming that the same Manzanares SUTPP prototype geometry is employed in these locations. These nine locations are Muscat (Oman), Al Jawf (Libya), Riyadh (Saudi Arabia), Karachi (Pakistan), Ahmedabad (India), Havana (Cuba), Culiacán (Mexico), Dhaka (Bangladesh), and Baise (China). The energy generation intensity (EGI) for the Manzanares-type solar updraft tower power plant in these nine examined locations was between 0.93 kWh/m2 per year (in Baise) and 2.28 kWh/m2 per year (in Muscat). Also, Muscat had the smallest seasonality index (maximum-to-minimum monthly electric output) of 1.90, while Baise had the largest seasonality index of 4.48. It was found that the main limitation of the overall SUTPP energy conversion efficiency is the chimney efficiency (the process of accelerating the air after entering the chimney). This study concludes that solar updraft towers (SUTs) cannot compete with existing mature and modular renewable energy alternatives, particularly photovoltaic (PV) panels, if the aimed use is commercial utility-scale electricity generation. Instead, SUTs may become attractive and achievable if viewed as hybrid-use projects by serving primarily as a large-scale greenhouse area for agricultural applications while secondarily allowing energy harvesting by generating clean (emissions-free) electricity from the incoming solar radiation heat. [ABSTRACT FROM AUTHOR]

This study investigates the impact of different biofuels, such as pure hydrogenated vegetable oil, hydrogenated vegetable oil, and biobutanol, as well as their blends, on the non-energetic operational characteristics of a compression ignition internal combustion engine. The research investigations were conducted using a turbocharged direct injection compression ignition engine that was put within a Skoda Octavia 1.9 TDI automobile. Throughout the investigation, the primary emphasis was placed on analyzing energy characteristics such as power, brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), and other related factors. The analysis involved the utilization of multiple combinations of bio-based fuels, namely four mixes of HVO with biobutanol (HVO100, HVOB5, HVOB10, and HVOB20), which were subsequently compared to fossil diesel (D100). The findings of the study indicate that the utilization of HVO100 fuel results in notable reductions in power output and mass fraction when compared to D100 gasoline. HVO100 fuel demonstrates superior performance to D100 gasoline, exhibiting a range of 1.7% to 28% improvement in brake-specific fuel consumption. Additionally, at an engine speed of 4500 rpm, the use of HVO100 fuel leads to a decrease in brake thermal efficiency of 4.4%. [ABSTRACT FROM AUTHOR]

Geoenvironmental engineering involves defining solutions for complex problems, such as containment systems management, contaminant transport control, wastewater management, remediation of contaminated sites and valorization of geomaterials and wastes. In the last years, energy harvesting (EH)—or energy scavenging—methods and technologies have been developed to reduce the dependence on traditional energy sources, namely fossil fuels, and nuclear power, also responding to the increase in energy demands for human activities and to fulfill sustainable development goals. EH in geoenvironmental works and the surrounding soil and water environment includes a set of processes for capturing and accumulating energy from several sources considered wasted or unusable associated with soil dynamics; the stress and strain of geomaterials, hydraulic, vibrations, biochemical, light, heating and wind sources can be potential EH systems. Therefore, this work presents a review of the literature and critical analysis on the main opportunities for EH capturing, accumulating and use in geoenvironmental works, among basic electric concepts and mechanisms, analyzing these works in complex conditions involving biological-, chemical-, mechanical-, hydraulic- and thermal-coupled actions, concluding with the main investigation and challenges within geoenvironmental aspects for EH purposes. [ABSTRACT FROM AUTHOR]

This study combines experimental and numerical evaluations of Vortex Bladeless Wind Turbines (VBWTs) to understand their potential in renewable energy generation. The methodology employs Two-Way Fluid–Solid Interface (FSI) simulations, alongside real-world data, providing important insights into the turbine's vibration dynamics and flow interactions during operation. Key findings include identifying optimal vibration frequencies and amplitudes that enhance energy harvesting and a clear advantage in power-generation estimations shown by one of the models used. The study reveals possible applications of VBWT in various settings like airport runways, highways, and buildings, indicating a promising avenue for incorporating such renewable-energy solutions. Discussions on the economic feasibility and environmental benefits of VBWT deployment are also presented, suggesting a need for further research and optimization in this area. A conceptual generator design and business model are introduced as part of a broader discussion on technology integration and energy storage. The research in this study encompasses experimental and numerical analysis, to achieve a broader understanding of the workings of a VBWT, realizing the feasibility of using such systems in lower-wind-speed conditions and upscaling to higher-wind-speed cases. [ABSTRACT FROM AUTHOR]

This paper deals with an electrothermal model of a thermoelectric converter dedicated to performing simulations of coupled thermal and electrical phenomena taking place in harvesting processes. The proposed model is used to estimate the electrical energy gain from waste heat that would be sufficient to supply electronic circuits, in particular autonomous battery-less nodes of wireless sensor networks (WSN) and Internet of Things (IoT) devices. The developed model is not limited to low-power electronic solutions such as WSN or IoT; it can also be scaled up and applied to simulations of considerably higher thermal power conversion. In this paper, a few practical case studies are presented that show the feasibility and suitability of the proposed model for complex simultaneous simulation processes in both the electrical and thermal domains. The first example deals with a combined simulation of the electrothermal model of a thermoelectric generator (TEG) and an electronic harvester circuit based on Analog Devices' power management integrated circuit LTC3108. The second example relates to the thermalization effect in heat sink-less harvesting applications that could be mitigated by a pulse mode operation. The unique contribution and advancement of the model is the hierarchical structure for scaling up and down, incorporating the complexity of the Seebeck effect, the Joule effect, heat conduction, as well as the temperature dependence of the used materials and the thermoelectric pellet geometries. The simulations can be performed in steady as well as transient states under changing electrical loads and temperatures. [ABSTRACT FROM AUTHOR]

In recent years, global warming and environmental problems have become more serious due to greenhouse gas (GHG) emissions. Harvesting solar energy for production and logistic activities in supply chains, including factories and distribution centers, has been promoted as an effective means to reduce GHG emissions. However, it is difficult to balance the supply and demand of solar energy, owing to its intermittent nature, i.e., the output depends on the daylight and season. Moreover, the use of large-capacity solar power generation systems and batteries incurs higher installation costs. In order to maintain low costs, demand-to-supply management of solar energy, based on appropriate seasonal analysis of power generation and consumption and the capacity planning for power generation and the storage battery, is necessary. In this study, the on-demand cumulative control method is applied to actual power consumption data and solar power generation data estimated at a distribution center. Moreover, the monthly, seasonal, and temporal characteristics of power generation and consumption at the distribution center are analyzed. Additionally, the total amount of power purchased is investigated for solar energy demand-to-supply management. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) arrays are often affected by partial shading (PS), which can significantly reduce their power output. Dynamic reconfiguration is a promising technique for mitigating the negative effects of PS by adjusting the electrical connections of the PV modules in real-time. This paper introduces a hierarchical-based switching block scheme for the dynamic reconfiguration of PV arrays under PS conditions. With the aim of mitigating the negative impact of PS on PV arrays, the proposed system employs a low complexity and easily scalable architecture, making it well-suited for practical applications. Comparative assessments against conventional configurations such as bridge-linked (BL), total-cross-tied (TCT), and series–parallel (SP) reveal superior energy harvesting efficiency for the proposed system under various shading conditions. The hierarchical switching block architecture, featuring multiple levels of switching blocks, enables efficient and flexible reconfiguration of the PV array, even in the presence of complex shading patterns. Through extensive simulations, the system consistently outperforms conventional configurations by adapting effectively to changing shading patterns and optimizing the PV array's output. The proposed switching block (SB) reconfiguration technique significantly outperforms existing methods like TCT, Sudoku, dynamic proposals, and Magic Square in terms of both power generation (up to 42.52% increase) and efficiency (up to 42.13% improvement) under diverse partial shading conditions. The proposed hierarchical-based switching block scheme thus presents a promising solution for enhancing the dynamic reconfiguration of PV arrays under PS conditions, offering a balance between low complexity, scalability, and superior energy harvesting efficiency for practical applications in the realm of solar energy. [ABSTRACT FROM AUTHOR]

This paper presents the results of the design process focused on the development of the energy subsystem (ES) of a wave energy converter (WEC). The ES is an important electrical part that significantly affects the energy reliability and energy efficiency of the entire WEC device. The designed ES was intended for compact WECs powering IoT network devices working in the distributed grid. The developed ES is an electronic circuit consisting of three cooperating subsystems used for energy conversion, energy storage, and energy management. The energy conversion subsystem was implemented as a set of single-phase bridge rectifiers. The energy storage subsystem was a battery-less implementation based on the capacitors. The energy management subsystem was implemented as a supervisory circuit and boost converter assembly. The designed ES was verified using the physical experiment method. The model experiment reflected the operation of the designed ES with a piezoelectric PZT-based WEC. The experimental results showed a 41.5% surplus of the energy supplied by ES over the energy demanded by the considered load at a duty cycle of ca. 6 min—37.2 mJ over 26.3 mJ, respectively. The obtained results have been evaluated and discussed. The results confirmed the designed ES as a convenient solution, which makes a significant contribution to the compact WECs that can be applied among others to a distributed grid of autonomous IoT network devices powered by free and renewable energy of sea waves. Finally, it will also enable sustainable development of mobile and wireless communication in those maritime areas where other forms of renewable energy may not be available. [ABSTRACT FROM AUTHOR]

Wireless energy harvesting (EH) communication has long been considered a sustainable networking solution. However, it has been limited in efficiency, which has been a major obstacle. Recently, strategies such as energy relaying and borrowing have been explored to overcome these difficulties and provide long-range wireless sensor connectivity. In this article, we examine the reliability of a wireless-powered communication network by maximizing the net bit rate. To accomplish our goal, we focus on enhancing the performance of hybrid access points and information sources by optimizing their transmit power. Additionally, we aim to maximize the use of harvested energy, by using energy-harvesting relays for both information transmission and energy relaying. However, this optimization problem is complex, as it involves non-convex variables and requires combinatorial relay selection indicator optimization for decode and forward (DF) relaying. To simplify this problem, we utilize the Markov decision process and deep reinforcement learning framework based on the deep deterministic policy gradient algorithm. This approach enables us to tackle this non-tractable problem, which conventional convex optimization techniques would have difficulty solving in complex problem environments. The proposed algorithm significantly improved the end-to-end net bit rate of the smart energy borrowing and relaying EH system by 13.22 % ,   27.57 % , and 14.12 % compared to the benchmark algorithm based on borrowing energy with an adaptive reward for Quadrature Phase Shift Keying, 8-PSK, and 16-Quadrature amplitude modulation schemes, respectively. [ABSTRACT FROM AUTHOR]

Vertical-axis wind turbines (VAWTs) are an innovative solution for energy harvesting, as they harness the power of the wind by enabling rotational motion around a vertical shaft situated on the ground. This paper deals with the design optimisation of VAWT systems for highway energy harvesting. The four design parameters, blade number, blade curvature angle, blade thickness and blade diameter ratio, have been investigated to find their respective optimalities for the enhanced energy efficiency of VAWT systems. Computational fluid dynamics (CFD) simulations are conducted in Ansys Fluent using a Banki turbine model created in Solidworks®, with a constant velocity inlet of 4 m/s and rotational speeds ranging from 0.5 to 3 rad/s. The simulations consider the placement of the turbine in the central reservation of a highway with a windshield for enhanced performance. From the results, it was observed that increasing blade thickness and blade number improve turbine performance, with maximum power coefficients achieved at specific tip speed ratios (TSRs). The optimal blade diameter ratio has been found to be approximately 0.75 for TSR values between 0.1 and 0.5, whilst a ratio of 0.83 gave the best performance at higher TSR values. Also, a blade curvature angle of 60 degrees has been found optimal for slow rotations, while 100 degrees yielded the highest power coefficient for faster rotations. The study could also highlight the significance of blade curvature angle variation, resulting in a notable 14% performance increase compared to the baseline. The geometric changes proposed in the study allow for greater power extraction from the same turbine footprint, leading to increased energy efficiency in VAWT systems. [ABSTRACT FROM AUTHOR]

Electromechanical energy harvesters are used to extract energy from vibrations occurring in nature, transport, or industry. The main problem with such solutions is that their output voltage is completely dependent on the frequency and amplitude of the vibrations, which can make it difficult to power a specific device or charge a battery. Therefore, it is necessary to use solutions that meet these requirements. Most harvesters contain additional, specialized mechanical gearboxes, called mechanical rectifiers or power electronic interfaces, used to match the harvester's output voltage to the load. Design work was carried out, the construction of the proposed energy harvester was described, and the operation principle of the author's control algorithm was presented. The results of the research confirm the possibilities of influencing the output voltage and power of the harvester system independently of the frequency and excitation amplitude. [ABSTRACT FROM AUTHOR]

This article presents research about a hybrid power system dedicated to Internet of Things (IoT) nodes. As an introduction, performance tests of the harvesters, that is, a 40 × 40 mm Peltier cell based on Bi2Te3 and three solar cells, monocrystalline, polycrystalline, and amorphous, are presented. The study established the dependence of the effect of generated power on the load resistance. Thus, it states how the internal resistance of the harvesters changes. Following the above tests, a complete power unit with a single harvester and an LTC3108 conversion circuit, as well as an energy buffer in the form of a 1 mF supercapacitor, were built and tested. The unit with a thermoelectric generator generated power from 14 to 409 µW. The unit with a 65 × 65 mm polycrystalline cell generated power from 150 to 409 µW. Next, a hybrid system was built and tested with both of the aforementioned harvesters, which generated power from 205 to 450 µW at 2000 lx illumination and a temperature difference of 20 °C for the thermoelectric generator claddings. [ABSTRACT FROM AUTHOR]

For many years, technological progress has been observed in the field of minimizing energy consumption by devices and increasing the efficiency of energy generation from freely available sources. Energy harvesting (EH) is one of the ways to increase the energy available in vehicles. The manuscript presents the results of a series of laboratory tests carried out in a wind tunnel using a 1:10 scale model of an SUV. The aim of the tests was to measure the air velocity in the footsteps of the car. The speed field has been identified at more than 188,000 points in the space behind or next to the car, considering the symmetry of the vehicle. The total energy was aggregated for 2760 points in a vertical plane perpendicular to the plane of symmetry. From the tests carried out, it was found that the highest speed was achieved just behind the trunk of the car, at a distance of about 20% of the length of the car. Interestingly, the speed in this area was higher than the speed of the car. [ABSTRACT FROM AUTHOR]

In this paper, we exploit state-of-the-art energy management in sustainable smart cities employing the Internet of Energy (IoE). The primary goal of this study is to leverage cutting-edge energy management techniques through the IoE in sustainable smart cities to bring about significant improvements in clean energy processes while targeting environmental benefits, efficiency enhancements, sustainability, and cost reduction. In this work, we present a comprehensive exploration of energy management strategies within the context of IoE-enabled sustainable smart cities. Firstly, we provide a detailed classification of diverse energy management approaches pertinent to IoE-based sustainable smart cities. This classification covers a spectrum of methodologies, including scheduling optimization, the design of low-power device transceivers, cognitive frameworks, and the integration of cloud computing technology. Furthermore, we highlight the pivotal role of smart grids as fundamental elements in the establishment of smart cities. Within this context, we offer a comprehensive overview of the essential components that underlie smart grids, with a notable focus on the intricate realm of micro/nanogrids. Moreover, our research delves comprehensively into energy harvesting within the context of smart cities. We analyze crucial facets like receiver design, energy optimization methods, a variety of energy sources, efficient energy scheduling approaches, and the establishment of effective energy routing mechanisms. Additionally, we delve into the multifaceted nature of sustainable smart cities across various domains. Our investigation reaches its culmination in the creation of a novel conceptual framework and the identification of enabling technologies centered on effective energy management. Lastly, we contribute to the field by outlining the current research challenges and mapping potential research directions relevant to energy management within sustainable smart cities, capitalizing on the capabilities of the IoT. [ABSTRACT FROM AUTHOR]

Airborne wind energy systems (AWES) are more efficient than traditional wind turbines because they can capture higher wind speeds at higher altitudes using connected kite generators. Securing a real wind turbine or a site with favorable wind conditions is not always an assured opportunity for conducting research. Hence, the Research and Development of the Laboratory Scale Airborne Wind Energy Conversion System (LAWECS) require a better understanding of airborne wind turbine dynamics and emulation. Therefore, an airborne wind turbine emulation system was designed, implemented, simulated, and experimentally tested with ground data for the real time simulation. The speed and torque of a permanent magnet synchronous motor (PMSM) connected to a kite are regulated to maximize wind energy harvesting. A field-oriented control technique is then used to control the PMSM's torque, while a three-phase power inverter is utilized to drive the PMSM with PI controllers in a closed loop. The proposed framework was tested, and the emulated airborne wind energy conversion system results were proven experimentally for different wind speeds and generator loads. Further, the LAWECS emulator simulated a 2 kW, 20 kW, and 60 kW designed with a projected kite area of 5, 25, and 70 square meters, respectively. This system was simulated using the Matlab/Simulink software and tested with the experimental data. Furthermore, the evaluation of the proposed framework is validated using a real-time hardware-in-the-loop environment, which uses the FPGA-based OPAL-RT Simulator. [ABSTRACT FROM AUTHOR]

Variable-cross-section beams have better mass and strength distribution compared with constant cross-section beams, which can optimize the harvesting power of piezoelectric vibration energy harvesters, which are widely used in self-supplied and low-power electronic devices, providing more convenience and innovation for the development of micromechanical intelligence and portable mobile devices. This paper proposes a piezoelectric energy harvester with a tristable-exponential-decay cross section, which optimizes the strain distribution of the cantilever beam through exponential decay changes to improve the harvesting efficiency of the harvester in low-frequency environments. First, the nonlinear magnetic force is obtained based on the magnetic dipole, and the dynamic model is established by using the Euler–Bernoulli beam theory and Lagrangian equation. The influence of the structural parameters of the harvester on the system dynamics and output characteristics is analyzed in the two dimensions of time and frequency, and the influence of the exponential decay coefficient on the system dynamic response and output power is deeply studied. The research shows that the exponential decay section can reduce the first natural frequency of the cantilever beam; by changing the amplitude, frequency, d and dg of the excitation acceleration, the switching of the monostable, tristable and bistable states of the system can be realized. With a decrease in the exponential decay coefficient, under a low-frequency excitation of 0–7 Hz, the output power of the cantilever beam per unit volume is significantly improved, and under a 4 Hz low-frequency excitation, the acquisition output power per unit volume of the cantilever beam is increased by 7 times, thus realizing low-frequency, high-efficiency energy harvesting. [ABSTRACT FROM AUTHOR]

Real-time condition monitoring of various types of machinery using sensor technology has gained significant importance in recent years. However, relying on batteries to power these sensors proves to be sub-optimal, as it necessitates regular charging or replacement. To address this, harvesting waste energy from ambient sources emerges as a more efficient alternative. Everyday applications like vehicle wheels, fans, and turbines present ambient sources of waste rotational energy. In this study, we propose a novel rotational energy harvester design that converts rotational energy into linear energy. This linear energy impacts a piezoelectric disk, generating an electric potential. Through simulations, the expected electric potential at varying frequencies was evaluated. Subsequently, experimental tests were conducted by connecting the harvester to a rectifier for AC-to-DC signal conversion and an oscilloscope for voltage measurement. A DC motor replicated the rotational motion at the frequencies from the simulation, and the power output was measured. Using the power transfer theorem, simulation and experimental power outputs were calculated, resulting in values of 188, 513, and 1293 μW and 88.89, 336, and 923 μW, respectively. These results reveal that the designed harvester is competitive with those of existing rotational energy harvester designs, demonstrating the promising potential of this novel harvester. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have unique features, including intrinsic porosity, crystallinity, and tunability, making them desirable materials for diverse applications ranging from environmental remediation to energy harvesting. Among these applications, COFs are extensively studied for their photocatalytic hydrogen evolution by converting solar energy into clean and renewable fuel via water splitting. COFs have several advantages over conventional inorganic catalysts, such as tunable band structures, high surface areas, and low cost. However, the research in this field is still in the early stages, and COFs still face some challenges, such as low charge carrier mobility, high exciton binding energy, and poor stability. To overcome these challenges, various design strategies relying on a mechanistic approach have been developed to design and modify COFs for enhanced photocatalytic performance. These include extending the π-conjugation, incorporating heteroatoms or metal complexes, and donor–acceptor (D–A) configuration, which ultimately improves the light absorption charge separation of COFs. Additionally, blending COFs with other functional materials, such as inorganic-organic semiconductors, can create synergistic effects to boost photocatalytic activity. In this review, the design aspects of the fabrication of COFs as effective photocatalysts have been reported. [ABSTRACT FROM AUTHOR]

A novel deterministic method to harvest energy within a broadband frequency (0~25 kHz) from a mass-in-mass metamaterial is presented herein. Traditional metamaterials are composed of multiple materials (named as resonators and matrix) with different mechanical properties (e.g., stiffness, density). In this work, the stiffnesses of matrix materials are altered systematically to allow diversified property mismatches between the constituent components to introduce local resonance in the unit cell. While local resonance leverages wave energy passing through the acoustic metamaterials trapped within the relatively soft matrix as dynamic strain energy, a strategic and deterministic methodology is investigated to obtain a broadband local resonance frequency. The frequency band can then be utilized to harvest the trapped energy by embedding a smart material inside the matrix which is capable of electromechanical transduction (e.g., lead zirconate titanate). This concept has been proved numerically by harvesting energy at a broadband frequency with a power density of ~10 μW/in2. Finally, an experimental study is performed to prove the hypothesis proposed in this article. [ABSTRACT FROM AUTHOR]

Wireless energy harvesting enables the conversion of ambient energy into electrical power for small wireless electronic devices. This technology offers numerous advantages, including availability, ease of implementation, wireless functionality, and cost-effectiveness. Radio frequency energy harvesting (RFEH) is a specific type of wireless energy harvesting that enables wireless power transfer by utilizing RF signals. RFEH holds immense potential for extending the lifespan of wireless sensors and wearable electronics that require low-power operation. However, despite significant advancements in RFEH technology for self-sustainable wearable devices, numerous challenges persist. This literature review focuses on three key areas: materials, antenna design, and power management, to delve into the research challenges of RFEH comprehensively. By providing an up-to-date review of research findings on RFEH, this review aims to shed light on the critical challenges, potential opportunities, and existing limitations. Moreover, it emphasizes the importance of further research and development in RFEH to advance its state-of-the-art and offer a vision for future trends in this technology. [ABSTRACT FROM AUTHOR]

Standalone photovoltaic (PV) systems are crucial for providing reliable, cost-effective, and sustainable energy to remote or off-grid locations with limited or no access to the traditional electrical grid. In this context, the sizing of a standalone PV system for a remote health clinic involves determining the clinic's power requirements and matching them with an appropriate PV system's capacity. Maximum power point tracking (MPPT) is a critical aspect of standalone PV systems, as it optimizes the PV system's power output by adjusting the PV array's operating point to the maximum power point (MPP) of the PV module. However, the non-linear behavior of PV systems due to exposure to changing climate conditions and partial shading can hide some faults, making traditional protection devices incapable of detecting them. Therefore, the design of an optimal simulation model of a properly sized standalone PV system is important for simulating and collecting the necessary data to diagnose faults. In this study, a standalone PV system for a hypothetical clinic in Malaysia is proposed, and it is sized based on peak sun hours. Its simulation model is built using MATLAB/Simulink (R2018b). The proposed simulation system's performance was evaluated considering the proper design of the PV system's boost converter within the changing conditions, and its ability to harvest maximum power points is considered a criterion for evaluating the performance. Various scenarios of uniform irradiance, uniform temperatures, shading effects, and sequential partial shading scenarios were implemented to evaluate the proposed simulation model. Results show that the proposed simulation model is suited to simulating different tests as it can harvest maximum power in all test scenarios. [ABSTRACT FROM AUTHOR]

Energy harvesting, a cutting-edge technology that captures wasted energy from vehicles, constitutes a means to improve the efficiency of electric vehicles. Dissipated energy can be converted into electricity using regenerative energy recovery systems and put to various uses. This study tenders a thorough examination into energy recovery technologies which could be applied to the various types of energy dissipated in electric vehicles. The paper investigates the possible sources of energy recoverable from an electric vehicle, as well as the various types of energy dissipated. It also examines the energy recovery technologies most frequently used in vehicles, categorizing them according to the type of energy and application. Finally, it determines that with further research and development, energy harvesting holds considerable potential for improving the energy efficiency of electric vehicles. New and innovative methods for capturing and utilizing wasted energy in electric vehicles can be established. The potential benefit of applying energy recovery systems in electric vehicles is a vital issue for the automobile industry to focus on due to the potential benefits involved. The ongoing progress currently being made in this field is expected to play a significant role in shaping the future of transportation. [ABSTRACT FROM AUTHOR]