Electrical Performance Evaluation Research Articles

Comparative Analysis and Integrated Methodology for the Electrical Design and Performance Evaluation of Thermoelectric Generators (TEGs) in Energy Harvesting Applications

Comparative Analysis and Integrated Methodology for the Electrical Design and Performance Evaluation of Thermoelectric Generators (TEGs) in Energy Harvesting Applications

Intelligent measurement method of transition resistance of insulation fasteners in urban rail transit system based on SSA-optimized algorithm

Rail-to-earth transition resistance characterizes the amplitude of stray current leakage in urban rail transit system using electric traction, which is critical for evaluating failure risk of metal infrastructures caused by electrochemical corrosion. However, detection method commonly used in the field exhibit measurement errors resulting from the limitation of measuring principle and measuring distance, which will seriously affect the accuracy of electrical insulation performance evaluation of the whole system. In view of this, this paper proposes a data-driven method for accurately measuring rail-to-earth transition resistance in urban rail transit system based on CDEGS-based simulation and SSA-optimized algorithm. CDEGS model was built to construct database for machine learning of SSA-RF network structure. SSA algorithm was used in the measurement model to optimize the topology of the random forest (RF) structure. Proposed ensemble in this paper was proved to conduct transition resistance regression with a mean relative accuracy rate of 98.85 %. Results of sensitivity analysis indicate that proposed measurement method shows acceptable robustness, which allows the algorithm parameters to fluctuate within a certain range when applied in the field. Besides, in the case of uniform and non-uniform insulation degradation, the proposed method shows good performance in assessing insulation performance. This provides a feasible foundation for future applications of the proposed method in failure risk evaluation of buried infrastructures.

Thermal and electrical performance evaluation of single and double pass photovoltaic-thermal solar collector with cross-flow baffles and varying transparency: A computational analysis

The present work deals with the development of a semi-transparent photovoltaic thermal (PV-T) solar collector (STPVT) through computational fluid dynamics (CFD) modelling using COMSOL Multiphysics. The study was carried out in three stages; firstly, the CFD model was developed for STPVT and validated with experimental data. Secondly, three different configurations of semi-transparent PV-T collector were investigated, i.e., single pass with PV module on top (SPC), double pass with PV module on top followed by glass cover and absorber plate (DPT), and double pass with PV module in between the glass cover and absorber plate (DPS). The absorber plate was incorporated with cross-flow baffles for improved thermal performance due to increased surface area and turbulence. The study found a thermal efficiency of 76.94 % for DPS configuration and a total heat utilisation of 289.63 W at 50 % transparency level, i.e., 2–4 times higher than other configurations. Furthermore, the DPS model was investigated for thermal and electrical performance with different PV module transparency levels (52,42,27,13 %). The DPS with 18 solar cells having 13 % transparency exhibited peak power density (8 %) at 717 W/m2 and 101.89 °C panel temperature, achieving superior thermal efficiency (84 %) and total heat utilisation (315.09 W), surpassing configurations with higher transparency.

Measurement and Simulation of 2.25 kWp grid-connected amorphous photovoltaic station in a hot desert environment

This work investigates measurements and simulations of a 2.25 kWp grid-connected amorphous photovoltaic power plant mounted on a parked car in a hot desert environment. This power station is located at applied research unit field (URAER), in the Ghardaia region, southern region. The simulation is carried out using PVSYS software. This includes evaluation of meteorological and electrical parameters performance of studied PV system such as reference PV system, PV array yield (YA), Final yield (YF), PV array and system losses, array and system efficiency, performance ratio (PR). The array nominal energy estimated at STC is 5695 kWh/year. The energy estimated injected into the grid is 4648 kWh/year.

Validation of a platinum bioelectrode model for preclinical electrical and biological performance evaluation.

High throughput testing of clinically representative Pt electrodes requires an inexpensive, efficient method of production. The aim of this study was to develop a facile platinum (Pt) model electrode (PME) and assess its production process, stability, and reproducibility. In this study a new model electrode was developed using representative substrates and dimensions as state-of-the-art electrode arrays used for neural stimulation. It was found that the PME is a highly reproducible robust system with similar electrochemical performance but with lower variability than other neural prosthetic arrays.Clinical Relevance- As an estimate these novel model electrodes cost 300 times less than a cochlear implant, can be manufactured in a tenth of the time and with a less than 10% failure rate. It is expected that model electrodes with low variability of electrical properties will significantly improve preclinical validation testing of electrochemical stimulation, surface modifications, and coatings.

OPV-PCM-ETFE foils in use for public buildings: electrical performance and thermal characteristics

ETFE (ethylene tetrafluoroethylene) foil integrated organic photovoltaic cells (OPV) is a promising new building material that can convert solar energy into electricity and thus facilitate the aim of carbon neutrality. The electricity generation is significantly influenced by the high temperature coexisting in the composite OPV-ETFE foils. Using phase change materials (PCM) to regulate thermal effects can improve energy conversion and achieve better building thermal performance. The lack of the relationship between ETFE layer, OPV layer and PCM layer is the main reason that limits the understanding of how to utilize such materials for designing new public buildings. This paper thus investigates the basic performance of the OPV-PCM-ETFE foils, with a special emphasis on the dynamic temperature characteristics and the enhanced electrical performance. The new material composed of an OPV layer, a PCM (RT-28HC) layer and an ETFE layer from the top to the bottom is developed and characterized. The experimental results show that a significant temperature difference between specimen surface and rear face demonstrates the excellent performance of temperature regulation and that the open-circuit voltage keeps at a relative stable value due to the PCMs. Furthermore, the comparison analysis validates that the thermal performance of the OPV-PCM-ETFE foils is dependent on the solar irradiance and the PCM amount. In addition, the distribution of the PCM and the incorporation of the air cavity play a role in the temperature distribution. Generally, these properties provide the crucial insights into the evaluation of electrical and thermal performance of the OPV-PCM-ETFE foils.

Measurement and Prediction of Micronewton Class Thrust of Electric Propulsion Based on the Torsional Pendulum and Machine Learning Technique

Accurate and direct measurement of thrust is the most fundamental requirement in the evaluation of electric thruster performance. This article performed the measurement and prediction of the micronewton class thrust of micro gridded ion thrusters (μGITs) based on a novel design of torsional pendulum and high precision neural network models. The developed torsional pendulum adopts specially designed liquid metal connectors to eliminate the interference caused by the power supply cables and propellant feeding lines, realizing an accurate thrust measurement of radio frequency (RF)- and dc-μGIT from micronewton level to millinewton level with a measuring range of 0–10 mN and a resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.4~\mu \text{N}$ </tex-math></inline-formula> . Results show that the RF-μGIT generates a thrust of 0.46–2.43 mN for the RF power from 100 to 120 W and the xenon flow rate from 0.75 to 1.50 sccm. The dc-μGIT generates a thrust of 0.016–0.310 mN for the acceleration voltage from 700 to 1050 V and the flow rate from 0.2 to 2.0 sccm. Both the artificial neural network (ANN) and the radial basis function neural network (RBF-NN) are adopted to predict the relationship between the thrust and input parameters of RF-μGIT. The predicted thrusts by ANN deviate about 10% from the measured data, and the maximum relative deviation using RBF-NN model is about 2%. Furthermore, the RBF-NN model is used to obtain the distribution maps of thrust and specific impulse under 600 different working conditions and provides a solution for intelligent regulation of thruster performance. For the first time, the combination of thrust measurement and machine learning (ML) provides a new approach for the fast performance evaluation, prediction and regulation of electric thrusters.

Multi-aspect approach of electrical and thermal performance evaluation for hybrid photovoltaic/thermal solar collector using TRNSYS tool

• Hybrid solar photovoltaic/thermal collectors are investigated. • Multi-aspect approaches for electrical and thermal evaluation are conducted. • A new TRNSYS component of PV/T is created based on the Fortran language. • The PV/T system with a PID controller is the most efficient system for electrical conversion. • The PV/T with an ON/OFF controller is the best in thermal conversion. The integration of photovoltaic (PV) module and thermal solar collector shows a strong potential for incorporation into hybrid solar-thermal (PV/T) system, mainly due to space constraints and benefits of electrical and thermal concurrent power generation. This work verifies, analyses, and compares a new component of PV/T which was created and programmed based on factual specifications in the TRNSYS environment and built a dynamic model of PV/T system. The new component of the PV/T was validated and evaluated experimentally and numerically using multi-aspect evaluation approaches. Electrical and thermal behaviour were studied by examining the effects of temperature controllers, using the daily hot water consumption profile, ambient temperature, cell temperature, and slope angles. In addition, the new component of the PV/T was compared with standard solar collector units and PV systems. This study found that the results of simulations and experiments were remarkably consistent and matched well. The correlation coefficient was 0.983 and 0.9783 for the thermal and electrical efficiencies, respectively. The most efficient PV/T system in electrical conversion was the PV/T with a PID controller, and the most efficient system in thermal conversion was the PV/T with an ON/OFF controller. The fulfilment model can serve for further PV/T system performance assessments.

Advanced 1200V SiC MOSFET Concept Based on Singular Point Source MOS (S-MOS) Technology

This paper presents a Singular Point Source MOS (S-MOS) cell concept suitable for SiC MOSFETs targeting low conduction losses, low switching losses and high robustness. The S-MOS concept differs from standard Planar or Trench MOS cells in the manner by which the total channel width per device area is determined. For the proof of concept and device electrical performance evaluation, the paper will provide 2D and 3D TCAD simulations results for 1200V SiC MOSFETs including the S-MOS and reference planar and trench structures.

A combined thermal and electrical performance evaluation of low concentration photovoltaic systems

Due to the expectations of improving the overall efficiency of photovoltaic installation, the increase solar irradiation that could be converted into electricity should be considered as an alternative solution for existing PV technologies. Low-concentration photovoltaic systems such as reflective surfaces or Fresnel micro lens plates were chosen for this study because they were economically justified and easy to install and maintain. The low concentration systems were studied theoretically and experimentally under sunny and cloudy weather conditions. After the initial optimization of the system geometry and construction, both electrical and thermal performances were evaluated and compared with a reference PV panel. In addition, the effect of additional irradiation as well as panel temperature was studied for a specific period using thermography and digital image techniques. It was revealed that the highest improvement in energy performance was achieved by the panel with reflective surfaces, while the Fresnel plate considered here slightly decreased this performance in comparison with the reference case. The consideration ends with an economic analysis of both systems in the case of free-standing PV installation and a list of recommendations are presented, based on the empirical results. The highest improvement of energy performance can be achieved by the implementation of reflective surfaces, about 20% of the average daily global efficiency, and 15% on electrical production. In the case of the Fresnel micro lens, a decrease in both global efficiency and electricity production is observed, 8% and 21%, respectively. Regarding the temperature of PV panels, significant overheating was not registered; about 45–55 °C for the entire experimental test.

Evaluation of Mechanical and Electrical Performance of Aging Resistance ZTA Composites Reinforced with Graphene Oxide Consolidated by SPS.

This paper presents a study of Al2O3–ZrO2 (ZTA) nanocomposites with different contents of reduced graphene oxide (rGO). The influence of the rGO content on the physico-mechanical properties of the oxide composite was revealed. Graphene oxide was obtained using a modified Hummers method. Well-dispersed ZTA-GO nanopowders were produced using the colloidal processing method. Using spark plasma sintering technology (SPS), theoretically dense composites were obtained, which also reduced GO during SPS. The microstructure, phase composition, and physico-mechanical properties of the sintered composites were studied. The sintered ZTA composite with an in situ reduced graphene content of 0.28 wt.% after the characterization showed improved mechanical properties: bending strength was 876 ± 43 MPa, fracture toughness—6.8 ± 0.3 MPa·m1/2 and hardness—17.6 ± 0.3 GPa. Microstructure studies showed a uniform zirconia distribution in the ZTA ceramics. The study of the electrical conductivity of reduced graphene oxide-containing composites showed electrical conductivity above the percolation threshold with a small content of graphene oxide (0.28 wt.%). This electrical conductivity makes it possible to produce sintered ceramics by electrical discharge machining (EDM), which significantly reduces the cost of manufacturing complex-shaped products. Besides improved mechanical properties and EDM machinability, 0.28 wt.% rGO composites demonstrated high resistance to hydrothermal degradation.

Heat transfer efficiency and electrical performance evaluation of photovoltaic unit under influence of NEPCM

In present study, a design of PVT unit involving PCM has been analyzed. The influence of several types of nanofluids and NEPCMs at different concentrations on the system efficaciousness is assessed. The SiC, ZnO, MCNT (multi-walled carbon nanotube), Al2O3, Cu, and Ag nanoparticles are utilized within water and phase change material at concentrations of 0, 0.02, 0.04. The impact of different flow rates and various solar radiation intensities are also evaluated. In addition, the influence of using multilayer of PCMs (including OM35, RT35HC, and eicosane) with different combinations inside the PCM receptacle on the productivity of component is assessed. At last, a comparison study between PVT, PVT/PCM, PVT-TE (thermoelectric module), and PVT-TE/PCM collector is conducted to assess the impact of TE module integration with the PVT systems from the electrical and thermal perspectives. To simulate the procedure of the charging of paraffin, the enthalpy-porosity approach is used. In addition, a transient solver and pressure-based finite volume approach are selected to perform the simulation. Based on the acquired results, enhancing the flow rate of coolant from 3.77 to 7.54 ml/s leads to 7.21% reduction in liquid fraction. It also de-elevates the average PV temperature, average outlet temperature, and the PCM temperature by 7.06%, 35.13%, and 3.62%, respectively. Enhancement of the NEPCM concentration from 0 to 4% improves the escalating charging rate, however, it de-elevates the temperature of PV unit and the Tout of coolant slightly.

Evaluation of Electrical Performance and Life Estimation of PPs for HVDC Power Cable

Demand and need for the application of high voltage direct current (HVDC) are increasing because of high capacity and long-distance transmission. Research on polypropylene (PP) that can increase the operation temperature compared to existing insulation is constantly being considered. This study aimed to evaluate the electrical performance and estimate the life of HVDC application of PP. In this study, a DC V-t characteristic tests were conducted on three types of PP sheets at a temperature of 110 °C. In addition, a life estimation formula based on the electrical stress was derived and the electrical performances were evaluated. The experimental results show that the life exponent of material mixed with block copolymer, homo polymer and high density polyethylene (HDPE) was 23 and the electrical performance was 17% better than block copolymer, thereby demonstrating the reliability and electrical performance for application of HVDC.

Thermal Behaviour of a Cylindrical Li-Ion Battery

This paper presents an experimental evaluation of thermal and electrical performances of a 26650 cylindrical Lithium Iron Phosphate/graphite battery cell. Thermal management of Lithium batteries is a fundamental issue of electric mobility, where batteries are subjected to severe operating conditions. Therefore, battery heat generation is a very important characteristic to be studied. In this work cell performances were assessed during battery discharge at ambient temperature over a wide range of discharge rates. The cell surface temperature was measured both with thermocouples and infrared thermography. Furthermore, also the open circuit potential and entropic heat coefficient were experimentally measured. Based on this experimental data, a simplified battery thermal model was used to evaluate the battery heat generation. The results show a substantial increase of battery surface temperature especially at high discharge rates. During discharge, the heat generated is greater at low battery state of charge due to the sudden decrease of cell potential. The contributions to heat generation are also carefully evaluated.

Degradation analysis of photovoltaic modules after operating for 22 years. A case study with comparisons

The analysis of degradation mechanisms of photovoltaic (PV) modules is key to ensure its current lifetime and the economic feasibility of PV systems. Field operation is the best way to observe and detect all type of degradation mechanisms. This paper presents the main signs of degradation on 56 m-Si PV modules caused by outdoor exposure after a period of 22 years in Seville, Spain. Results are compared with other research works conclusions that analyse the degradation of identical PV cells and same manufacturer, after an exposure period of 12, 15 and 17 years. The analysis was conducted by visual inspection, infrared thermography, electroluminescence (EL) and electrical performance evaluation. The mean peak power degradation has been 30,9% in the 22 operation years, equivalent to 1,4% per year, which corresponds mainly to a loss in short-circuit current and, in a less degree, to loss in fill factor and open circuit voltage. The most significant defects found were severe browning, milky pattern and oxidation of the metallization grid. Those defects seem turns severe failures when exposure period is more than about 20 years and could explain the high degradation rate based on a comparison performed with other research works.

A study on electrical conductivity and performance evaluation of ohmic evaporation process of grape juice

Examination of the Ohmic evaporation process in terms of electrical conductivity value and laws of thermodynamics is limited in the literature. In this study, the moisture content of the grape juice sample was concentrated from 5.75 kg water/kg Dry-Matter (DM) to approximately 2 ± 0.3 kg water/kg DM by an ohmic evaporator. Evaporation process was applied in three different voltage gradients (16–24 V/cm) by Ohmic evaporator. The electrical conductivity value was found to be between 0.21 and 0.77 S/m during the heating process while it was between 0.77 and 1.01 S/m during the evaporation process. In addition, when evaluating this process concerning thermodynamic laws, it was stated that increasing voltage gradient had a positive effect on energy efficiency, exergy efficiency, and improvement potential values. To conclude, it was achieved that the ohmic heating-assisted evaporation process could be used in the concentration of grape juice and an effective system with an average of 80% energy efficiency. Practical applications As the ohmic heating process is known as a homogeneous, rapid, and efficient heating technique, its use in food applications is gradually increasing in recent years. Evaporation process is one of the preservation methods used especially in the fruit juice industry. An alternative evaporation method has been obtained by integrating the ohmic heating process into the evaporation process. It was determined that the voltage gradient used and foam formation were an effect on the electrical conductivity and performance analyses. It was determined that as the voltage gradient increased, the amount of water removed from the grape juice increased (kg/s) and the total processing time shortened. It is considered that this study may be a data source in the literature related to pilot and industrial-scale production lines by determining electrical conductivity value during the evaporation of grape juice and investigating energy efficiencies.

Electrical conductivity and performance evaluation of verjuice concentration process using ohmic heating method

AbstractThe verjuice sample (14.5 ± 0.2% total soluble solid [TSS] content) was concentrated (at 102 ± 2°C evaporation temperature) until reach 50% TSS content by applying ohmic heating at 13, 15, 17, and 19 V/cm voltage gradients. The total process times up to 50% TSS content were determined as 2,100, 1,500, 1,200, and 1,020 s for 13, 15, 17, and 19 V/cm, respectively. The electrical conductivity values increased until reach 32% TSS content and then showed a decrease until the final TSS content. The total energy consumption values increased as the voltage gradient decreased. The total power and specific water removal ratio (SWRR) values decreased as the voltage gradient decreased. The efficiency of ohmic heating assisted concentration process increased with the applied voltage gradient and it ranged from 71.27 to 75.22%. By evaluating the effects of ohmic heating conditions applied in the present study on total process time, total energy consumption, and process efficiency, 19 V/cm voltage gradients could be recommended to be optimum evaporation conditions of verjuice concentration in case of decreasing process time and higher energy efficiency.Practical applicationsFruit juices are generally concentrated to extend their shelf life. Therefore, for concentration purposes, various techniques, such as thermal evaporation, freezing methods, and membrane techniques, are applied in the fruit juice industry. This technique has some disadvantages, such as high energy requirements, the formation of undesirable compounds, high initial investment cost, and high failure rate to reach the desired total soluble solid content. The ohmic heating method, which is among the alternative heating methods, has advantages such as high energy efficiency, shorter processing time, higher product quality, and not causing wastewater. As a result of this study, it is thought that the verjuice samples were successfully concentrated up to 50% TSS content by using the ohmic heating method and this method can be used as an alternative method instead of the traditional method due to higher process efficiency and shorter process time.

Research and Analysis on Evaluation Methods of Electrical Performance of Smart Energy Meters

Based on the technical specifications of smart meters, the electrical performance evaluation methods of single-phase smart meters are studied, and the accuracy, stability and safety of smart meters are analyzed and studied through specific data verification. Analysis the basic characteristics of the electrical performance of the smart energy meter, and evaluate the electrical performance based on the basic characteristics. Collect the specific working characteristic data of the intelligent electric energy meter, accurately measure the parameters of the intelligent electric energy meter, and analysis the electrical performance. Analysis the influence of the harmonic components of the power system on the measurement of the electric energy meter, study the power consumption of the smart electric energy meter, and the accuracy and stability of the operation.

Thermal and electrical performance evaluation of hybrid air PV/T collector – numerical analysis and experimental study

ABSTRACT The photovoltaic-thermal (PV/T) hybrid collector is the most generative technology solar energy, which has been invented to utilise electrical energy and heat from the solar system. This paper presents a numerical analysis and experimental validation of the thermal and electrical behaviour of the air PV/T collector based on the geometric design and the Tunisia climate conditions. PV/T system has lower thermal efficiency and higher electrical efficiency (14%) at high wind speeds. To improve the thermal efficiency, a sensitivity analysis studied across a range of the air channel depth (0.01–0.08 m) with different air mass flow rate. It was concluded that the thermal energy for a PV/T air system depends on the optimal depth and variations in mass flow rate.

A Combined Thermal and Electrical Performance Evaluation of Low Concentration Photovoltaic Systems

A Combined Thermal and Electrical Performance Evaluation of Low Concentration Photovoltaic Systems