Energy Harnessing Research Articles

A Review on “Wind energy fuel as a Power Source for Automobiles”

Requirement of energy for automobiles is increasing everyday as we take a step towards development. The use of nonrenewable energy sources such as fossil fuels is leading to an increase in pollution. There was research performed by the United States Environmental Protection Agency (EPA) in 2007 and it was found that a normal family car produces approximately three to four tonnes of carbon dioxide per year, similarly six tonnes of carbon dioxide was produced by a large four-wheel drive like a van yearly. The present energy scenario of energy generation and the pollution caused by automobiles due to conventional energy sources have made it necessary to harness energy from other unorthodox sources to run them. Electric vehicles have been developed to solve this problem, in a sense that they don’t release any harmful gases such as carbon dioxide and carbon monoxide. One major problem which still exists even in electric automobiles is that the electricity that they utilize is still generated from conventional sources. Thus, if we can somehow generate electricity from unconventional sources, it can solve our former problem. Wind energy fuel which can be harnessed from a moving vehicle is one of such unorthodox sources that could be harnessed and subsequently used to power automobiles. This paper is a review of different ways of how wind power can be harnessed to fully power an automobile.

MXene-based eutectic salt hydrate phase change material for efficient thermal features, corrosion resistance & photo-thermal energy conversion

Salt hydrate phase change materials (PCMs) possess low thermal conductivity, degree of supercooling, lack of corrosion resistance and poor photo thermal conversion ability. To overcome these challenges, a two dimensional, chemically stable, optically & thermally efficient MXene@eutectic salt hydrate composite PCM is developed for effective harnessing of solar energy and thermal energy storage (TES) applications. Low temperature eutectic salt hydrate PCM with phase transition temperature of 27.6 °C and 216 J/g melting enthalpy is developed using sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) based on Schrader equation. Advanced 2D layered material, MXene (Ti3C2) is synthesised from MAX phase (Ti3AlC2). Furthermore, MXene based PCM nanocomposite is developed with binary eutectic PCM of SSD/SPDD at different weight fractions through two step technique. Developed nanocomposite PCM exhibits better chemical stability, high optical absorbance of (1.1), low transmissibility (10.2 %), reliable thermal conductivity (0.621 W/m⋅K), improved melting enthalpy (161.2 J/g) and considerable cycle stability. The optical absorbance and thermal conductivity demonstrated a superior photo-thermal conversion capability and thermal networks for the developed MXene based composite sample at 0.9 wt% of MXene. The above properties are experimentally inferred by evaluating the developed MXene@ eutectic salt hydrate and base eutectic PCM under the solar simulator. The interfacial attraction between the two dimensional MXene nano flakes and the developed eutectic PCM ensures a promising ability to trap solar energy effectively for thermal regulation in a sustainable direction. Subsequently, the effect of MXene with SSD/SPDD in regard to the issue of corrosion is explored for copper and aluminium metal surface.

Self-Rotation of Electrothermally Responsive Liquid Crystal Elastomer-Based Turntable in Steady-State Circuits.

Self-excited motions, characterized by their ability to harness energy from a consistent environment and self-regulate, exhibit significant potential in micro-devices, autonomous robotics, sensor technology, and energy generation. This study introduces an innovative turntable system based on an electrothermally responsive liquid crystal elastomer (LCE). This system facilitates self-rotation within a steady-state circuit. Employing an electrothermal LCE model, we have modeled and numerically analyzed the nonlinear dynamics of an LCE-rope within steady-state circuits, utilizing the four-order Runge-Kutta method for calculations. The numerical results reveal the emergence of two distinct motion patterns in the turntable system under steady-state conditions: a self-rotation pattern and a static pattern. The self-rotation is initiated when the system's absorbed energy surpasses the energy lost due to damping effects. Furthermore, this paper delves into the critical conditions necessary for initiating self-rotation and examines the influence of various key dimensionless parameters on the system's rotation amplitude and frequency. These parameters include gravitational acceleration, the initial position of the mass ball, elastic stiffness of the LCE and spring, limiting temperature, heating zone angle, thermal shrinkage coefficient, and damping factor. Our computational findings establish that these parameters exert a modulatory impact on the rotation amplitude and period. This research enhances the understanding of self-excited motions and offers promising avenues for applications in energy harvesting, monitoring, soft robotics, medical devices, and micro- and nano-devices.

Self‐Charged Dual‐Photoelectrode Vanadium–Iron Energy Storage Battery

AbstractThe efficient utilization of solar energy in battery systems has emerged as a crucial strategy for promoting green and sustainable development. In this study, an innovative dual‐photoelectrode vanadium–iron energy storage battery (Titanium dioxide (TiO2) or Bismuth vanadate (BiVO4) as photoanodes, polythiophene (pTTh) as photocathode, and VO2+/Fe3+ as redox couples.) is proposed, which can autonomously charge under sunlight. The dual‐photoelectrode structure enables the efficient harnessing of solar energy. All processes are spontaneous and do not require external power sources. It is noteworthy that the vanadium–iron energy storage battery demonstrates excellent stability and remarkably low cost. The results show that the combinations of TiO2‐pTTh and BiVO4‐pTTh as photoelectrodes achieve spontaneous conversion rates of 29.17% and 25.46% for VO2+ and 25.6% and 23% for Fe3+ after 4 h of light charging. This study offers a promising solution for the development of large‐scale, low‐cost solar energy storage batteries.

Comparative study on the capture performance of two wave energy converters integrated into the jacket-frame foundation

The global pursuit of clean energy resources to cope with escalating energy demands has underscored the pivotal roles of wind and wave power as two prominent renewable energy sources for the power industry. In order to promote the comprehensive harnessing of ocean energy, research efforts have increasingly focused on hybrid approaches, aiming to concurrently capture wind and wave energies. This paper proposes two types of wind-wave hybrid device, which combines wind turbine with a wave energy converter (WEC), based on jacket-frame foundation. The numerical models of the WECs were created using SOLIDWORKS, and the subsequent simulations were conducted using ANSYS Workbench. The comparative analysis revealed that the heave-type WEC had less added mass and radiation damping, coupled with larger response amplitude operator (RAO) and shorter natural period compared to the swinging counterpart. Meanwhile, the swing-type WEC exhibited higher motion speed and greater support reaction force and connecting force, thereby exerting more pronounced influence on the foundation. However, the average hourly power generation of the swinging WEC was significantly better in terms of power capture. In practice, the choice between these WEC configurations should consider aligning the power matrix with the probability distribution of prevailing sea state conditions.

Hybrid deep learning model for wave height prediction in Australia's wave energy region

Waves are emerging as a renewable energy resource, but the harnessing of such energy remains among the least developed in terms of renewable energy technologies on a regional or a global basis. To generate usable energy, wave heights must be predicted in near-real-time, which is the driving force for wave energy converters. This study develops a hybrid Convolutional Neural Network-Long Short-Term Memory-Bidirectional Gated Recurrent Unit forecast system (CLSTM-BiGRU) trained to accurately predict significant wave height (Hsig) at multiple forecasting horizons (30 min, 0.5H; 2 h, 02H; 3 h, 03H and 6 h, 06H. In this model, convolutional neural networks (CNNs), long-short-term memories (LSTMs), and bidirectional gated recurrent units (BiGRUs) are employed to predict Hsig. To construct the proposed CLSTM-BiGRU model, historical wave properties, including maximum wave height, zero-up crossing wave period, peak energy wave period, sea surface temperature, and significant wave heights are analysed. Several wave energy generation sites in Queensland, Australia were tested using the hybrid deep learning CLSTM-BiGRU model. Based on statistical score metrics, scatterplots, and error evaluations, the hybrid CLSTM-BiGRU model generates more accurate forecasts than the benchmark models. This study established the practical utility of the hybrid CLSTM-BiGRU model for modelling Hsig and therefore shows the model could have significant implications for wave and ocean energy generation systems, tidal or wave height monitoring as well as sustainable wave energy resource evaluation where a prediction of wave heights is required.

Dual Axis Solar Tracker Using Arduino

Abstract: The biggest crisis we are heading into is the climate change due to excessive use of fossil fuels and to overcome these issues, we have only one solution that is utilizing Renewable Energy. Renewable energy is a type of energy that is harnessed from the nature without causing ill effects to the environment. One of the most prominent kinds of renewable energy is solar energy. The output electrical energy depends on the amount of sunlight falling on the solar panel. Traditionally, solar panels are fixed and the movement of sun over the horizon means that the solar panel does not harness maximum energy most of the time. In order to maximize the power from the solar panel, the panel should face the sun all time. In Arduino based solar tracker with the help of LDR and servo motor is used to generate maximum power.

Magnetoelectric coupling optimization in lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 and Ni0.5Zn0.5Fe2O4 nanocomposites for magneto-mechano-electric generator

Magneto-mechano-electric (MME) generators efficiently harness ubiquitous stray magnetic fields and convert them into electricity, capturing significant attention for powering innumerable wireless sensors. In this study, lead-free 0-3 particulate magnetoelectric (ME) nano-composite ceramics, specifically x(Ba0.85Ca0.15Zr0.1Ti0.9O3)-(1-x)Ni0.5Zn0.5Fe2O4 [x(BCT-BZT)–(1-x)NZFO], were synthesized using the sol-gel method. Subsequently, a flexible MME generator was designed, incorporating the optimized ME composite. Structural parameter calculations indicated higher tetragonal distortion of 0.4% in 0.4(BCT-BZT)-0.6NZFO, possibly due to uniform particulate distribution. The ME composites displayed uniform dual-phase microstructures, with 0.4(BCT-BZT)-0.6NZFO showing a higher NZFO concentration. The maximum values of the magnetodielectric (MD) and ME coupling coefficients have been determined to be -3.6% and 2.55 mV cm -1 Oe-1, respectively, for an x = 0.4 composite. The MME generator is designed using an optimized 0.4(BCT-BZT)-0.6NZFO ME composite with film thickness of 34 μm. This MME generator harvests a sinusoidal wave with a maximum output peak-to-peak voltage of 4.1 V when exposed to a weak AC magnetic field of 10 Oe at a frequency of 50 Hz. Additionally, the device demonstrates an exceptional optimal DC power density of 3.89 μW cm-3. The lead-free 0-3 particulate ME composite enables effective magnetic energy harnessing. As a result, it holds great promise as an efficient autonomous power supply for various Internet of Things based applications.

Serpentinization as the source of energy, electrons, organics, catalysts, nutrients and pH gradients for the origin of LUCA and life.

Serpentinization in hydrothermal vents is central to some autotrophic theories for the origin of life because it generates compartments, reductants, catalysts and gradients. During the process of serpentinization, water circulates through hydrothermal systems in the crust where it oxidizes Fe (II) in ultramafic minerals to generate Fe (III) minerals and H2. Molecular hydrogen can, in turn, serve as a freely diffusible source of electrons for the reduction of CO2 to organic compounds, provided that suitable catalysts are present. Using catalysts that are naturally synthesized in hydrothermal vents during serpentinization H2 reduces CO2 to formate, acetate, pyruvate, and methane. These compounds represent the backbone of microbial carbon and energy metabolism in acetogens and methanogens, strictly anaerobic chemolithoautotrophs that use the acetyl-CoA pathway of CO2 fixation and that inhabit serpentinizing environments today. Serpentinization generates reduced carbon, nitrogen and - as newer findings suggest - reduced phosphorous compounds that were likely conducive to the origins process. In addition, it gives rise to inorganic microcompartments and proton gradients of the right polarity and of sufficient magnitude to support chemiosmotic ATP synthesis by the rotor-stator ATP synthase. This would help to explain why the principle of chemiosmotic energy harnessing is more conserved (older) than the machinery to generate ion gradients via pumping coupled to exergonic chemical reactions, which in the case of acetogens and methanogens involve H2-dependent CO2 reduction. Serpentinizing systems exist in terrestrial and deep ocean environments. On the early Earth they were probably more abundant than today. There is evidence that serpentinization once occurred on Mars and is likely still occurring on Saturn's icy moon Enceladus, providing a perspective on serpentinization as a source of reductants, catalysts and chemical disequilibrium for life on other worlds.

Performance and Economical Analysis of Solar Roof Plant with and without Reflectors

Abstract: This thesis aims to explore the feasibility and potential benefits of implementing a solar roof plant in Gwalior, Madhya Pradesh. The escalating demand for energy, coupled with the urgent need to reduce greenhouse gas emissions, calls for innovative and sustainable solutions. Solar energy has emerged as a viable alternative to conventional power sources, offering significant environmental and economic advantages. This research focuses on Gwalior, a city with abundant sunlight and ample roof space, making it an ideal candidate for solar energy harnessing. The study begins with a comprehensive assessment of the current energy scenario in Gwalior, analyzing the energy consumption patterns and the existing power infrastructure. This analysis establishes a baseline for evaluating the impact and potential of a solar roof plant in the region. Key areas of investigation include the technical feasibility of installing solar panels on rooftops, the economic viability of the project, and the environmental benefits it would bring. The thesis also addresses the regulatory framework and policy support necessary to encourage solar power adoption in Gwalior. Key stakeholders, such as government bodies, utility companies, and local communities, will be involved in the research process to ensure a holistic approach. By utilizing advanced simulation tools and data analysis techniques, this thesis will quantify the energy generation potential of a solar roof plant in Gwalior. Factors such as solar irradiance, panel efficiency, and rooftop suitability will be considered to determine the optimal configuration and capacity of the plant. Furthermore, financial models will be developed to assess the return on investment and the long-term cost-effectiveness of the project. The findings of this study are expected to demonstrate the significant advantages of a solar roof plant in Gwalior. These advantages include reduced reliance on fossil fuels, decreased carbon emissions, and improved energy security. The research outcomes will contribute to the body of knowledge on solar energy implementation and serve as a valuable reference for policymakers, urban planners, and renewable energy enthusiasts.

Performance of a two-body heaving cylindrical wave energy converter on stepped sea bottom

The present study deals with the surface gravity wave interaction with a heaving dual concentric cylindrical wave energy converter (WEC) buoy system on the stepped sea bottom. The energy captured by linear electric generator (LEG), is directly proportional to relative heave motion of the present WEC buoy system. In the present study, the analytical diffraction and radiation problems are solved using the Fourier–Bessel series expansion method and matched eigenfunction expansion method (MEFEM) under the assumption of small amplitude water wave theory and structural responses. Wave exciting force acting on both vertical cylinders is obtained. The role of the step type bottom on the relative heave response amplitude operator (RAO) of the buoy system, is analyzed for various structural configurations and wave characteristics. A series of experiments are carried out in a two-dimensional wave flume both with and without the presence of step-type bottom. The computed results are in good agreement with the experimental results. It is found that the inclusion of artificial step at the sea bottom leads to higher wave energy harnessing. The findings of the present study are likely to be of immense help in the design and development of various point absorber-type WEC buoy systems.

Carbon dots tailoring the interfacial proton and charge transfer of iridium nanowires with stress strain for boosting bifunctional hydrogen catalysis

The effective harnessing of hydrogen energy relies on the development of bifunctional electrocatalysts that facilitate hydrogen evolution/oxidation reactions (HER/HOR) with high catalytic activity. The design of such electrocatalysts requires the consideration of not only the volcano relationship with hydrogen binding energy (HBE) or hydrogen adsorption Gibbs free energy (ΔGH) but also the regulation of catalytic kinetics such as interfacial proton/electron transfer. In this work, unique one-dimensional iridium nanowires with compressive stress are successfully prepared and combined with carbon dots (Ir NWs/CDs). Acting as an electrocatalyst for HER in 0.5 M H2SO4, the optimal Ir NWs/CDs only requires an 18 mV overpotential to achieve a current density of −10 mA cm−2. Furthermore, the optimal Ir NWs/CDs shows high HOR performance with a mass activity (@ 50 mV versus RHE) 1.5 times that of 20% Pt/C and excellent anti-CO toxicity ability which is twice the level of the PtRu/C catalyst. Ir NWs/CDs exhibit enhanced HER/HOR activity due to (1) the appropriate modulation of the binding energy to hydrogen intermediate facilitated by the compressive stress applied to the Ir structure and (2) the improved proton/electron transfer kinetics by optimizing the electronic properties and surface structures through tailored CDs. This study delivers a new strategy for designing and synthesizing efficient acidic HER/HOR bifunctional catalysts.

Programmable Droplet Bouncing on Bionic Functional Surfaces for Continuous Electricity Generation

AbstractThe natural phenomenon of droplets bouncing on various surfaces holds remarkable potential for applications like water transportation, self‐cleaning, antifreezing, etc. However, achieving precisely controlled patterned droplet bouncing on functional surfaces with accurately controlled factors like bouncing velocity and trajectory in three dimensions remains a formidable challenge. In this context, a concept of bionic hydrophobic functional surfaces composed of mushroom‐like microstructures is introduced. These microstructures are crafted using the projection microstereolithography (PµSL) based 3D printing technique, subsequently coated with a hydrophobic spray. By finely adjusting the geometric attributes and inclination angles of these micromushrooms, the ability is gained to meticulously manipulate the bouncing velocity and trajectory of water droplets. The most optimal performance is demonstrated by a droplet exhibiting a maximal jumping distance and height respectively of 2.5 and 7.1 mm with 50° inclined micromushrooms. Notably, these specially designed micromushrooms orchestrate diverse behaviors in droplet bouncing, encompassing patterned bouncing, antigravity jumps, and directional water transportation. Additionally, the functional surface's adaptable self‐cleaning capability facilitates the harnessing of energy from rainfall on large surfaces, offering potential applications in realms, such as self‐cleaning mechanisms, droplet capture, water conveyance, and clean energy generation.

Characterization of the Mechanical Properties of Low Stiffness Marine Power Cables through Tension, Bending, Torsion, and Fatigue Testing

The exploitation and harnessing of offshore marine renewable energy have led to an increased demand for reliable marine power cables with long service lives. These cables constitute a considerable share of the total installation cost of offshore renewable energy facilities and have high maintenance and repair costs. The critical characteristics of these power cables must be determined to reduce the risk of exceeding their ultimate strength or fatigue life, which can result in unwanted and unexpected failures. This study investigates dynamic marine power cables that are suitable for application in devices that harness energy from ocean currents, waves, and tides. Tension, bending, torsion, and fatigue tests were conducted on three dynamic power cables (1 kV, 3.6 kV, and 24 kV) that have high flexibility, i.e., low mechanical stiffness. The specimen lengths and axial pretension force were varied during the tests. The results are discussed in terms of the mechanical fatigue degradation and ultimate design load, and the key observations and lessons learned from the tests are clarified. The study’s main contribution is the results from physical component testing of the dynamic marine power cables without metallic armors, which can be used to calibrate numerical models of this type of dynamic marine power cable in the initial design of, e.g., inter-array cables between floating wave energy converters. The benefits offered by this type of cable and the importance of the results for creating reliable numerical simulation models in the future are highlighted.

Pond ash as a potential material for sustainable geotechnical applications - a review.

Energy-harnessing sources significantly influence a country's infrastructure and economic development. Though nuclear and hydel power sources are used for energy harnessing, thermal sources are still the primary power source in India and contribute to 75% of the demand. Thermal power plants exploit large volumes of coal reserves. The combustion of coal leads to 30%-40% of waste ash residues such as Fly ash and Bottom ash. Though Fly ash finds greater applicability, pond ash poses a severe environmental hazard due to its large occupancy of terrain in ash dykes and lagoons. Many research efforts are underway to utilize pond ash in various structural and geotechnical infrastructure projects; however, there are still limitations and apprehensions about its properties and determination. The present study provides a detailed review of the morphological and chemical properties. Further, the geotechnical attributes of pond ash, including strength characteristics, consolidation parameters, and durability aspects, are critically reviewed for the probable application as fill material for backfill and many other applications. Based on the earlier research on pond ash, it could be comprehended that pond ash has wide property variability and finds compatibility with many other pozzolanic admixtures and, in this way, finds broader applicability in geotechnical projects. The way forwards could be a significant step towards cleaner and greener technology.

Thermo-catalytic reforming of general waste to produce biofuels

This work investigates the feasibility of extracting biofuels from general wastes, with significant non-recyclable and inorganic components, through the novel thermo-catalytic reforming (TCR®) technology. Two forms of general waste (Up-Sieve Material and Grey Compost) supplied by Risorse Ambiente Palermo (RAP) are studied. Each feedstock is shredded, pelletised and characterised. Analyses of the feedstock materials show the Up-Sieve Material has a higher heating value (HHV) of 17.6 MJ kg−1 with an ash content of 19.60% (by weight), while the Grey Compost has a HHV of 11.5 MJ kg−1 and an ash content of 40.16%. The results of the TCR® experiments on both feedstock materials show they can be thermochemically converted into energy carriers in significant quantities. The characterisation results of the oil and char from the Up-Sieve Material show they have HHVs of 38.2 MJ kg−1 and 13.6 MJ kg−1 respectively, while the oil and char from the Grey compost have HHVs of 37.0 MJ kg−1 and 5.7 MJ kg−1 respectively. In addition, the biogases produced from both feedstock materials are rich in hydrogen (up to 30% by volume each). Hence, apart from the chars and the reaction product water, the products can be further processed into biofuels due to their fuel-grade properties. Therefore, the successful extraction of biofuels from general waste is an important step in renewable energy harnessing, waste management and environmental protection.

Techno-economic analysis of marine hybrid clusters in two potential Latin American markets

Contemporary communities require innovative solutions to cope with projected increases in demand for natural resources. Diversification and modernization of the energy matrix through the affordable and efficient harnessing of marine renewable energies (MRE) are possible means to mitigate the vulnerability of coastal communities and climate change. While the offshore wind sector has reached sufficient maturity to compete in the energy market, other MRE, such as wave energy, are still in the development phase, which limits their financing and commercial deployment. This study aims to evaluate the techno-economic feasibility of maritime hybrid clusters (MHC) powered by wave energy converters (WEC) and offshore wind turbines (OWT) to electrify households and the marine aquaculture sector, where electricity surpluses can be stored in lithium-ion batteries or for green hydrogen production. Different scenarios for WaveDragon (WD) and Pelamis (PEL) WEC farms were studied in two coastal communities, Coquimbo (Chile) and Ensenada (Mexico). The mean annual wave power availability at Coquimbo is high (26.05 kW/m) and of Ensenada, moderate (13.8 kW/m). The wave energy shows less inter- and intra-annual variability in Coquimbo than in Ensenada. The hybridization between WECs and OWT covers the total electricity consumption, where the PEL-OWT system is the cost-effective option in Ensenada and WD-OWT in Coquimbo. Ensenada demonstrated a higher electricity surplus than Coquimbo, profitable result of storing it to sale in the electricity market or for hydrogen production. For both selected WECs, the seaweed aquaculture integration in a blue economy framework generates higher returns than households, higher in Coquimbo than Ensenada.

NEW DESIGN OPTIONS FOR THE IMPROVEMENT OF THE MUTRIKU POWER PLANT

The research based on the development of OWC devices continues growing and nowadays there are endless options that have already been studied. From the type of turbine and its control, to the most efficient energy conversion system or design, the OWC technology needs to be further developed in order to be economically attractive.
 
 This research studies several possibilities to improve the efficiency of the Mutriku breakwater wave plant. On the one hand, the L-shape configuration of this plant allows studying a new configuration based on the coupling of the well-known U-shape [1], to create a new L+U-shape breakwater. In addition, the installation of harbor-walls has been proven as a promising option to enhance the interior damping of the camera [2], and this option seems to be very promising because of the design of the Mutriku plant allows its performance. Finally, a design based on the sharp-edges round off its being studied in order to reduce the energy losses and therefore enhance the energy harnessing of the plant.
 
 The experimental work has been carried out in the 12.5 m long wave flume located at the laboratory of Fluid Mechanics of the Energy Engineering Department (UPV/EHU). The physically constructed OWC device corresponds to one of the cameras installed at the Mutriku breakwater wave plant, an isolated camera, according to the construction plan and applying a 1:36 scale. All the experiments were carried out at two tides that correspond to the medium and maximum equinoctial live tides of Mutriku location. According to the information of the Basque Coast sea states [3], a constant incident regular waves of 30 mm were generated at several periods: 0.7<T[s]<1.7 for the medium tide and 0.7<T[s]<2.1 for the maximum tide.
 
 The L+U-shape was created with two lateral walls joined by frontal walls of different heights (W), as shown in Figure 1-left, that were positioned at several distances from the physical model. However, another L+U-shape was considered using a transversal wall of different heights and without lateral walls (TW, Figure 1-right), and placing at several distances form the plant.
 The obtained results reveals that the promising configuration corresponds to the one containing lateral walls, so that the influence of harbor walls will be further studied.
 

Eco-friendly coconut shell biochar based nano-inclusion for sustainable energy storage of binary eutectic salt hydrate phase change materials

Eco-friendly, stable and thermally reliable nano enhanced phase change materials (PCMs) with improved thermal property and photo absorbance are vital competencies for solar energy harnessing. In the proposed research, we develop and investigate the morphological, chemical, optical and thermal features of biochar-eutectic PCM composite for clean energy storage. Herewith, primarily coconut shell-based biochar nanoparticle (BNP) is synthesized through carbonization process in vacuum oven at 130 °C followed by wet ball milling to reduce the size. Coconut shell being a feasible candidate in terms of economical, pore structured and light weight ensures better binding, uniform dispersion and improved intermolecular attraction with PCM. The synthesized BNP is evenly spread into the surface morphology of inorganic binary eutectic PCM comprising of 62% of sodium sulphate decahydrate (SSD) and 38% of sodium phosphate dibasic dodecahydrate (SPDD). Electromagnetic spectrum absorbance in the range of infrared and visible rays increased from 0.09 to 0.84 (833%) and transmissibility has been reduced from 83.7% to 15.11% with BNP. Developed BNP composite eutectic PCM demonstrate higher thermal conductivity (0.715 W/m⋅K) on comparison with base eutectic PCM (0.464 W/m⋅K) owing to the presence of carbon element and porous nature of BNP. Heat flow curves specifies increment in melting enthalpy of eutectic PCM from 202.3 J/g to 218.1 J/g with energy storage efficiency of 71.7%. On the basis of thermophysical properties obtained, the developed BNP composite PCM is expected to contribute effectively for thermal regulation applications.

Electromagnetic energy harvesting via flow-induced vibration of flexible diaphragm in the presence of square cylinders at varied incidence angles: An experimental investigation

This study designs an electromagnetic energy harvester that uses a magnet in translation within a coil to harness energy from flow-induced vibrations when wall confinement affects a change in the wake formation behind a bluff body. An attached permanent magnet surrounded by a coil is attached to a flow channel with a flexible diaphragm, and a square cylinder acts as the bluff body that generates a vortex-induced street, thereby oscillating the diaphragm and generating electrical energy. The main novelty presented in the current investigation is developing a quick and efficient way of capturing fluid energy for practical applications, at the cost of augmented mechatronical complexity. Fluid flow and electromagnetic induction convert flow energy into electrical energy, and the influences of the Reynolds number (Re = 3000, 4000, and 5000) and the position of square cylinders (X*=X/D) on the dynamic characteristics are considered. As a result of different incidence angles (α) and spacing between two identical square cylinders (L*=L/D), Reynolds number and incidence angles have significant effects on the harvesting of energy. Additionally, based on experimental data, an output voltage of 0.04 V can be generated when the excitation pressure oscillates at about 20 Hz. Whether a single square or two identical squares are arranged, the 45-degree incidence angle is the most suitable arrangement for power conversion, and L*=4 can produce maximum energy for all configurations. Finally, the experimental results provide deeper insight into the physics behind the relationship between square spacing, rotation angle, and energy harvesting. Regarding hydroelastic energy extraction, tandem diamond configurations have substantial advantages over square ones. With high amplitudes and high frequencies, tandem diamond cylinders can generate mechanical power even beyond typical circular cross-sections. Furthermore, complementary numerical simulations are presented to provide a solid foundation for the reasoning behind the variation in extracted energy as well as complement the experiment results. By conducting numerical simulations, it is found that changing the incidence angle can significantly alter the flow patterns, which is attributable to the sequential formation of a primary vortex from the lee of the bluff body.