Electrical Conversion Efficiency Research Articles

Constructing independent CNTs conductive network to boost combustion performance of metastable intermixed composites

AbstractNovel metastable intermixed composites (MICs) constructed by carbon nanomaterials are expected to achieve high energy content and high combustion efficiency, but traditional preparation technologies always bring barely improvement in performance. Herein, novel PVDF/CuO/Al@CNTs MICs with independent continuous carbon nanotubes (CNTs) conductive networks were prepared by thoroughly utilizing the conductivity and photothermal properties of CNTs. A conductive network can be constructed at the interface of each encapsulated PVDF/CuO/Al particle with the addition of >0.5 wt% CNTs. The great increase in electrical and thermal conductivity of PVDF/CuO/Al@CNTs MICs indicates excellent energy transfer efficiency across the sample. Significant enhancement of the combustion reaction has been achieved, with the minimum ignition energy and ignition delay time of PVDF/CuO/Al@CNTs3 reduced by ~31% and ~50%, respectively. This indicates that the CNTs with unique photothermal properties can be utilized as an effective igniter. Moreover, the optimal PVDF/CuO/Al@CNTs1 MICs enhanced the pressurization rate (~300%), energy output (~55%), and combustion velocity (~200%). The mechanism of the fast combustion reaction can also be discussed by the weak interface interaction and the energy conductive of the CNTs network throughout the sample. This work provides a modern strategy for strong combustion MICs that can be generalized and applied in the field of energetic materials.Highlights An independent continuous CNTs conductive network was prepared with a small amount of CNTs. The electrical and heat conversion efficiency is greatly improved. CNTs with unique photothermal properties can be utilized as an effective igniter. The laser sensitivity is improved, and the reaction energy, pressure, and pressure rates are significantly increased. The combustion performance was significantly improved, and more intense, and the combustion speed was significantly increased.

Adaptive bicycle: A novel approach to design a renewable and energy-efficient electric bicycle with manual charging

This study focuses on developing an adaptive bicycle prototype with a manual charging mechanism for renewable energy. In response to environmental concerns and the demand for eco-friendly transportation, the research introduces a sustainable approach for short-distance travel. The goal is to demonstrate human power as an effective alternative to non-renewable energy by converting cycling’s rotational force into electrical energy. This energy is stored in a specialized battery and used to power the bicycle with an electric motor’s assistance. The methodology involves constructing and testing a prototype to capture and store energy during pedaling, analyzing mechanical components, electrical conversion, and battery efficiency. Controlled experiments assess the adaptive bicycle’s functionality and effectiveness in self-charging without external power. Results indicate successful integration of the manual charging mechanism with an average energy conversion efficiency of X%. The adaptive bicycle offers a sustainable solution for short-distance commuting, minimizing environmental impact and promoting an eco-friendly mode of travel. This innovative approach highlights the integration of renewable energy into everyday transportation, addressing environmental concerns by reducing dependence on non-renewable sources.

Development of Triboelectric Nanogenerators Using Novel 3D Printed Polymer Materials

Triboelectric nanogenerators (TENGs) are becoming attractive devices for harvesting mechanical energy. 3D printing (3DP) is a newly reported technique for the development of this device. This technique is not fully explored for the fabrication of triboelectric materials and compatible printing processes. Herein, three main 3DP techniques including powder‐based multijet fusion, resin‐based polyjet fusion, and filament‐based fused deposition modeling are utilized to investigate new sets of 3DP triboelectric materials. Mechanical to electrical conversion efficiency of 3D printed and commercially available negative and positive triboelectric materials are compared and investigated. Polyamide ‐12 (PA12), Veroclear, acrylonitrile‐styrene‐acrylate (ASA), copper‐coated polylactic acid (Cu‐PLA), polycarbonate (PC), and polyethylene terephthalate glycol (PETG) are fabricated using compatible 3D printing techniques. 3D‐printed PA12 is considered as a reference positive triboelectric layer. Meanwhile, 3D‐printed Veroclear, ASA, Cu‐PLA, PC, PETG, and commercial materials like Teflon sheets, PA6,6 conductive sheets, indium tin oxide‐coated polyethylene terephthalate, conductive‐nylon sheets, and PVDF membrane are selected as negative triboelectric materials. The maximum AC voltage of 80 V and maximum instantaneous current of 0.9 μA are produced by pairing 3DP‐PA12 and 3DP‐Veroclear under open circuit condition. This AC output is further converted to DC output using brdige rectifier circuitry to efficiently charge up the capacitor and glow series of 16 LEDs.

Design and analysis of an electromagnetic energy conversion device

In this study,we introduces an innovative device designed for wave-heat-electricity conversion, incorporating a classical split-ring resonator (SRR) and a Bi2Te3 semiconductor strip. This configuration is adept at absorbing electromagnetic energy, transforming it into thermal energy, and facilitating an electrical response. The paper delves into the detailed physical modeling and operational principles of the device. We begin by employing an equivalent circuit model to analyze the SRR's transmission characteristics and its temperature response under specific conditions. The investigation further extends to examining how structural dimensions and material properties affect the development of a local hotspot, leading to the refinement of the SRR resonant unit. We then integrate a Bi2Te3 semiconductor strip beneath this hotspot, enhancing the device's conversion capabilities. Our findings indicate an absorption efficiency of 0.085 at 2.45 GHz, a remarkable thermal conversion efficiency of 172.8 °C/W, and an electrical conversion efficiency of 0.195 mV/°C, all measured at an input power of 7 W. This research not only demonstrates the efficacy of the proposed device in wave-heat-electricity conversion but also provides a comprehensive reference for future advancements in this field.

Impacts of thermal and electric contact resistance on the material design in segmented thermoelectric generators

Segmented thermoelectric generators (STEGs) can exhibit present superior performance than those of the conventional thermoelectric generators. Thermal and electrical contact resistances exist between the thermoelectric material interfaces in each thermoelectric leg. This may significantly hinder performance improvement. In this study, a five-layer STEG with three pairs of thermoelectric (TE) materials was investigated considering the thermal and electrical contact resistances on the material contact surface. The STEG performance under different contact resistances with various combinations of TE materials were analyzed. The relationship between the material sequence and performance indicators under different contact resistances is established by machine learning. Based on the genetic algorithm, for each contact resistance combination, the optimal material sequences were identified by maximizing the electric power and energy conversion efficiency. To reveal the underlying mechanism that determines the heat-to-electrical performance, the total electrical resistance, output voltage, ZT value, and temperature distribution under each optimized scenario were analyzed. The STEG can augment the heat-to-electricity performance only at small contact resistances. A large contact resistance significantly reduces the performance. At an electrical contact resistance of RE = 10–3 K·m2·W−1 and thermal contact resistance of RT = 10–8 Ω·m2, the maximum electric power was reduced to 5.71 mW (90.86 mW without considering the contact resistance). And the maximum energy conversion efficiency is lowered to 2.54% (12.59% without considering the contact resistance).

Analysis and Design of Small-Impact Magnetoelectric Generator

For projectile impact penetration experiment, batteries or capacitors are usually used as power sources for projectile-borne recording devices. However, these power sources are easy to fail under high impact. In this paper, a small-impact magnetoelectric generator is introduced, which converts impact force into electrical energy to supply power for devices. The influence of generator structure on force–electricity conversion efficiency is analyzed. Based on the analysis, a small-impact magnetoelectric generator with double springs and two-part coils is designed. A hammer test is carried out on the generator. The test results show that this generator structure would achieve higher force–electricity conversion efficiency under small space.

Thermodynamic analysis of an air liquid energy storage system coupling Rankine cycle and methane steam reforming to improve system electrical conversion and energy efficiency

To solve the problem of the low electro-electric conversion efficiency of air liquid energy storage (LAES) systems and the low energy and exergy efficiency of LAES coupled with solar energy, a LAES system coupled with Rankine cycle and steam methane reforming system has been proposed. The system utilizes solar energy and couples the Rankine cycle to enhance power generation. The coupled steam methane reforming subsystem utilizes low temperature heat that is unavailable from the Rankine cycle for methane reforming to produce efficient fuel hydrogen. The article established the LAES and Rankine thermodynamic models, the economic model, and the solar heat flow test device for analytical studies. The findings indicate that the coupled system attains a staggered energy utilization, exhibiting a notably high exergy efficiency of 59.63%. This represents a marked enhancement of 15.45% when compared to the LAES system coupled with solar energy. The proposed system boasts an electro-electric conversion efficiency of 140.24%, demonstrating a remarkable 71.43% enhancement over the LAES-alone system. Moreover, the 1 MW system can produce up to 522.11 kg/h of hydrogen, the static payback period of the system is 6.12 years and the internal rate of return of the system can be 23.28%.

Optimal planning and design of waste-to-energy plant for aquaculture systems

Background: Several aquaculture industries in underdeveloped nations use fossil fuel-powered generators to produce electricity. This pattern has raised greenhouse gas emissions as well as the price of aquaculture products. Methods: To address this issue, this study contains a bi-objective model that optimizes the parametric settings of waste-to-energy (WTE) plants for aquaculture firms: Levelized cost of energy and power expenses for reverse logistics. The best values for these objectives were created using a genetic algorithm and goal programming. Results: Four planning periods were taken into account during implementation, and actual data were gathered from a Nigerian aquaculture company. The electricity costs from biodiesel ranged from N0.7541 per kW to N0.7628 per kW, respectively. Reverse logistics has energy costs ranging from N6 329 492.10 to N7 121 015.53. The proposed model produced average values for several WTE parametric parameters, including a 1.69 million kg hydrogen gas, a 59.16% hydrogen gas compression efficiency, and an 83.39% electricity conversion efficiency. Furthermore, the system had logistics’ minimum and maximum fractions of 0.18% and 21%, respectively. Conclusion: Our findings demonstrated how WTE parametric parameters impact the aquaculture industry’s electrical power unit.

Exergy and economic analysis of a photovoltaic panel cooling with air bubble induced water jacket

Solar photo voltaic (PV) panel performance is greatly affected by the rise in temperature of the PV panel. To increase the electrical conversion efficiency of the PV panel, assessments are made under various cooling circumstances. To assess the efficacy of the PV panel using a water-cooling system in the climate of Manipal, India, experimental studies were conducted in this research. The purpose of this research is to evaluate and compare various cooling strategies, such as Heat sink, water jacket, air bubble cooling and combination of these techniques. Air bubbles are introduced inside the cooling jacket, which generates turbulence motion and cools the PV panel. The cooling system is inspected while running at different panel temperatures. The percentage drop in maximum panel temperature is found to be highest at 15.36 % for the panel attached with water jacket and air bubble with heat sink combination. Also, the power output of the panel is found to be the highest for the above combination with the increase of 9.31%.

Fabrication of Ceramic-Polymer Piezo-Composites with Triply Periodic Minimal Interfaces via Digital Light Processing

The geometry of the phase interface in co-continuous piezoelectric composites is critical in improving their piezoelectric properties. However, conventional co-continuous piezoelectric composites are mostly simple structures such as wood stacks or honeycombs, which are prone to stress concentrations at the joints, thus reducing the fatigue service performance and force–electric conversion efficiency of piezoelectric composites. Such simple structures limit further improvements in the overall performance of co-continuous piezoelectric composites. In this study, based on the digital light processing 3D printing method, we investigated the influence of three different structures–the gyroid, diamond, and woodpile interfaces–on the piezoelectric and mechanical properties of co-continuous ceramic/polymer piezoelectric composites. These findings demonstrate that the gyroid and diamond interfaces outperformed the ceramic skeleton of the woodpile interface in terms of both mechanical and electrical properties. When the ceramic volume percentage was 50%, the piezo-composite of the gyroid surface exhibited the greatest hydrostatic figure of merit (HFOM), reaching 4.23×10−12 Pa−1, and its piezoelectric coefficient (d33) and relative dielectric constant (εr) reached 115 pC/N and 748, respectively. The research results lay the foundation for the application of co-continuous piezoelectric composites in underwater communication and detection.

An experimental investigation on thermal energy storage characteristics of nanocomposite particles dispersed phase change material for solar photovoltaic module cooling

Electrical conversion efficiency of a solar photovoltaic (SPV) module suffers due to increase in its temperature. An integration of thermal energy storage system with phase change material (PCM) in a SPV module will improve its overall efficiency by maintaining its temperature. Though, Paraffin is the most common PCM for SPV cooling application, its low thermal conductivity limits its performance. Thermal performance of the Paraffin can be enhanced by utilizing high conductive nanocomposite particles. In the present research work, the enhancement in thermal characteristics of Paraffin by dispersing titanium dioxide - silver nanocomposite particles are examined. Titanium dioxide - silver nanocomposite particles (NP) are synthesized using sol-gel process and characterized using standard techniques. The effect of dispersing titanium dioxide - silver nanocomposite particles (NP) in 0.5, 1, and 1.5 % mass concentrations with thermal cycling on thermal conductivity and hence the storage performance of Paraffin are investigated. Further, the chemical, physical and thermal stabilities of nanocomposite particles dispersed Paraffin (NCDPWX) are examined. When compared to the base Paraffin, the cycled NCDPWX with 1 wt% NP exhibits a better thermal conductivity (0.384 W/mK), melting heat capacity (128 kJ/kg), freezing heat capacity (119.46 kJ/kg), melting time (6.07 min), freezing time (10.11 min), thermal stability up to 352 °C, substantial reduction in degree of super cooling (3.96 °C), impregnation ratio (102.64 %), impregnation efficiency (100.92 %), thermal storage capability (98.31 %) and better chemical stability. Overall, the synthesized NCDPWX is a suitable thermal energy storage material for cooling of SPV modules.

Investigating the modified thermoelectric generator system performance

AbstractIt is essential to enhance the performance of the thermoelectric generator as lower efficiencies are obtained recently. This could be achieved by changing its dimensions in addition to copper strip thickness. The present study is performed to obtain the best dimensions of the P–N legs considering the interaction between all variables. To do this, a comprehensive TEG model is achieved in addition to utilizing the single-objective optimization technique. The main performance metrics, including electricity production and conversion efficiency, are assessed, and contrasted with the conventional TEG system since the simulation. The length of the legs and their cross-sectional area were shown to significantly affect power production. The thickness of the conducting plate, in contrast, barely matters. For instance, a P–N pair with legs that have a 2 mm2 cross-sectional area generates 0.4 W and 1.3 W for temperature differences of 480 °C and 980 °C, respectively. Furthermore, the equivalent efficiencies are 4.41% and 6.73%, respectively. Using the genetic algorithm revealed that the ideal values for the leg cross section, leg length, and conducting plate thickness are 1.84 mm2, 0.5 mm, and 0.44 mm, respectively. Once compared to the conventional system, using the optimization method results in an improvement in power production and conversion efficiency of about 247% at a temperature differential of 980 °C.

Pouch-sealing as an effective way to fabricate flexible dye-sensitized solar cells and their integration with supercapacitors

The scientific interest in integrated energy harvesting and storage (HS) devices has increased exponentially in the last decade since they represent an optimal solution to power portable electronic devices and low consuming Internet of Thing (IoT) sensor nodes. The integration of energy storage devices with photovoltaics can allow to avoid problems such as continuous battery replacement and periodic maintenance, reducing overall costs. In this context, dye sensitized solar cells (DSSCs) integrated with a supercapacitor represent the best choice in terms of lifetime, charge-discharge efficiency, and simplicity of connection avoiding electrical signal conditioning between the two devices. DSSCs have many similarities with supercapacitors, with the only aspect that remains uncovered being the sealing of the device. Herein we propose a common vacuum sealing technology for the integration of a supercapacitor and a DSSC made with shared current collectors, to maximize the integration between the two technologies. The HS device showed a maximum overall photon to electrical conversion and storage efficiency (OPECSE) of 6.10% under only 0.1 SUN illumination, thanks to the high photoconversion efficiency showed by the pouch sealed DSSC, equal to 6.62%. The HS device showed a high stability under bending condition and repeated photo-charge/discharge cycling.

ANSYS investigation of solar photovoltaic temperature distribution for improved efficiency

<p>A computational analysis of the influence of varying solar module material properties on operating temperature is presented and related to electrical conversion efficiency through the devised method. By varying the properties of density, specific heat capacity, and isotropic thermal conductivity for each material that comprises a solar module, density, and specific heat capacity were found to have the greatest influence on decreasing the operating temperature when increased by a factor of 50% for the glass layer, resulting in a decrease in temperature of 5.33 °C. Utilizing the devised method, which is based on the work of Palumbo, this temperature decrease was correlated to an electrical efficiency increase of 3.08%.</p>

Wave-heat-electricity conversion: Design and analysis of an electromagnetic energy conversion device

An innovative electromagnetic energy harvester was developed using a compact four-ring single-resistor unit cell. To achieve efficient conversion of electromagnetic waves into electricity, we integrated the high-performance Bi2Te3 thermoelectric material onto the load resistor. Remarkably, this unit cell exhibits exceptional energy harvesting capabilities at a frequency of 5.8 GHz while maintaining polarization insensitivity. Through comprehensive analysis, we evaluated the energy harvesting efficiencies, power loss distribution, and current density distribution. Additionally, we investigated the impact of incident power on the unit cell's temperature and energy conversion efficiencies. To enhance energy concentration on the load, we ingeniously designed an “L-shaped” metal through-hole structure within the four-ring single-resistor unit cell. Our results demonstrate that the four-ring single-resistor unit cell achieves an impressive harvesting efficiency of 94.5% at 5.8 GHz, with a thermal conversion efficiency of 43.3 °C/W, an electrical conversion efficiency of 0.23 mV/°C, and an electrical response rate of 9.4 mV/W. Notably, when subjected to a power input of 7 W, the unit cell produces an output voltage of 65.9 mV, and its theoretical maximum output power reaches 180 mW.

Experimental and Theoretical Evaluation of a Commercial Luminescent Dye for PVT Systems

Combining photovoltaic (PV) and photo-thermal (PT) energy collection strategies in a single system can enhance solar energy conversion efficiencies, leading to increased economic returns and wider adoption of renewable energy sources. This study focuses on incorporating a commercial luminescent organic dye (BASF Lumogen F Red 305) into ethylene glycol to explore its potential for PVT applications. The optical and electrical characteristics of the working fluid were evaluated at different temperatures under direct solar irradiance. Pristine ethylene glycol reduced the maximum PV cell temperature by 10 °C. The inclusion of luminescent dye at various concentrations further reduced the maximum temperature, with the lowest concentration achieving a 7 °C decrease compared to pristine ethylene glycol. The highest dye concentration (0.50 wt%) resulted in a significant temperature reduction of 12 °C. While electrical conversion efficiencies decreased with increasing dye concentration, all concentrations exhibited higher fill factors compared to the bare PV cell during the 100-min illumination period. A ray-tracing model was employed to analyze the behavior of the luminescent dye and quantify transmitted energy for electricity and thermal energy production. Different concentrations showed varying energy outputs, with lower concentrations favoring electrical energy and higher concentrations favoring thermal energy. Economic assessment revealed the viability of certain concentrations for specific countries, highlighting the trade-off between thermal and electrical energy generation. These findings provide valuable insights for PVT system applications in different geographical and economic contexts.

Numerical analysis of the effects of interconnector design and operating parameters on solid oxide fuel cell performance

Fuel cells can provide higher electrical conversion efficiency than traditional coal-fired power plants and electric generators based on internal combustion engines. In addition, high-efficiency solid oxide fuel cells (SOFC) have two specific advantages compared with other fuel cells as a result of their high-temperature operation. First, SOFCs are compatible with various fuels, ranging from hydrogen to CO and hydrocarbons. Second, SOFCs generate significant amounts of exhaust heat that can be used in combined heat and power systems. Furthermore, SOFCs have quiet and vibration-free operation, eliminating the noise typically associated with power generation systems. These fuel cells also produce no or very low levels of SO2 and NO emissions. In this study, we numerically investigated the performance of a planar SOFC with different interconnector designs at various operating temperatures. Multiple parameters were considered, such as interconnection geometries, anode and cathode materials, operating temperatures, and flow rates. As a result, the horizontal sinusoidal flow channel geometry, operating temperature of 600 °C, hydrogen gas flow rate of 86.5 SCCM/min, and oxygen gas flow rate of 28.75 SCCM/min, NiO anode material, and LSCF cathode material provided the greatest performance in terms of energy and current density.

Impacts of membrane fouling on nanofluidic salinity gradient energy conversion process

Fouling in the membrane interior of engineered large sized charged nanopores can significantly impact the transmembrane ion transportation characteristic. Here impacts of fouling characteristics on the energy conversion performance are investigated. When the fouling located near the low concentration end, the shadowing effect that decreases the effective charged surface area plays a dominant role, which weakens the EDL overlapping degree, and lowers the energy conversion performance. Fouling also brings about blocking effect that narrows the ion transportation channel, and improves ion separation. When the fouling located near the high concentration side, the blocking effect could override the shadowing effect, leading to upgraded energy conversion performance. Due to the coupling of the shadowing effect and blocking effect, the electric power and energy conversion efficiency could overwhelm the performance with no fouling existed. The electric power and energy conversion efficiency under the fouling of r=25 nm are increased by 26.47% and 7.43%, respectively.

Experimental research and optimization of a thermoelectric generator excited by pulsed combustion mode under limited heat dissipation for combined heat and power supply

In this paper, a scheme of pulse combustion mode with pulse input of gas is proposed to solve the problems of low output electrical performance and energy conversion efficiency of combustion-based thermoelectric systems under limited heat dissipation conditions, which is based on experiments. The characteristics of the thermoelectric system show that pulse combustion mode can increase the instantaneous temperature difference, so as to achieve the excitation effect on the output power. The relationships among output power, system efficiency, excitation intensity and pulse input parameters, and the geometry of thermoelectric modules are obtained. The influence of pulse input parameters on the excitation intensity is interactive, and top dead center of pulse inlet power is the parameter that has the greatest influence on the performance. Compared to the constant combustion mode, the pulse combustion mode can increase the output power by up to 28.3%. A maximum output power of 7.15 W with air-cooled heat dissipation and a maximum system efficiency of 3.26% were experimentally obtained, which is a 30% increase in efficiency over current air-cooled heat dissipation thermoelectric systems. Therefore, this paper can provide solutions for more practical power supply, provide effective and feasible guidance for the study of thermoelectric systems, and provide useful insights into the electrical properties of thermoelectric systems.

Ultra-high output hybrid nanogenerator for self-powered smart mariculture monitoring and warning system

Remote monitoring of distributed mariculture based on Internet of Things (IoT) has become an important part of smart marine agriculture, however, attaining stable and long-lasting power supply from conventional commercial batteries remains challenging, which significantly restricts the development of blue economic toward intelligent and diversified. Herein, a self-powered monitoring and warning system (SMWS) for smart mariculture based on a nodding duck structured multi-layer hybrid triboelectric-electromagnetic generator (MHTEG) is developed that endows improved electrical output performances and energy conversion efficiency. The structure of multi-electrode pairs is investigated with various ratios of nylon rod diameter to electrode width for optimizing the charge transfer efficiency of MHTEG. A peak output power density of 20.9 W/m3, ultra-high output energy of 39.6 mJ and excellent energy conversion efficiency of 22.61% can be achieved by the MHTEG with a high charge transfer efficiency of over 88%. Moreover, combining the MHTEG with an anti-theft and seawater sensor module, the remote SMWS is designed for monitoring and providing early-warning in marine farming. Such a design renders a practicable strategy and generic energy solution for efficient ocean wave energy scavenging and enabling distributed mariculture with intelligence.