Series-parallel Arrangement Research Articles

Optimal design of solar collector network in novel hybrid desalination plant

In this study, a new hybrid system for producing fresh water from seawater using solar energy is proposed. It suggests a modified and optimized approach to reduce the reliance on fossil fuels and decrease pollutants by also harnessing solar energy. The system includes flat-plate solar collectors, a multi-effect distillation through thermal vapor compression (MED-TVC) desalination unit, a pump, and a boiler. The flow rate of the produced fresh water and the specific cost of generating fresh water volume were considered objective functions and the system was optimized using as evolutionary algorithm. The algorithm was employed to determine 12 design variables. Series, parallel, and series-parallel configurations were examined as layouts for flat plate collectors. The results indicated that the series-parallel arrangement was the most effective layout for the collectors. The modeling was carried out for the city of Bandar Abbas in Hormozgan Province, Iran. The production of fresh water in series-parallel mode has increased by 12.15% and 27.83%, respectively, compared to the parallel and series configurations at the ideal point. An assessment of the results suggests that choosing the design point within the flow rate range of 4.19 L/s to 4.65 L/s is preferable.

Assessment of reliability measures and cost optimization of a solar seed sowing machine

PurposeIn this research work, the general form of reliability measures, which include availability, mean time to failure (MTTF), and sensitivity analysis, are investigated with their graphical representation, which would help designers and engineers improve the reliability of the system. Along with reliability assessment, a mathematical model is developed and solved to achieve the minimum cost of the system as well as maximum reliability.Design/methodology/approachIn the proposed work, a general model of a solar seed sowing machine is considered for reliability evaluation using the Markov model process. The proposed system is a series-parallel arrangement of components where three components, namely the solar panel, batteries and direct current (DC) motor, are connected in series while all the operators are connected in parallel. The implemented Markov model approach assesses several parameters of reliability, which opens the scope for improvement in reliability and other measures like mean time to failure (MTTF) and sensitivity of the proposed system. So that the machine can deliver the desired output on the field. Also, the particle swarm optimization (PSO) algorithm is applied to optimize the cost of the system with the desired level of reliability.FindingsImplementation of PSO provides the optimal cost for the proposed system with a predetermined level of reliability, which shows the relationship between reliability and cost of the system. Also, the Markov process approach provides the availability function, reliability function, reliability at different time values, MTTF and sensitivity of the proposed system.Originality/valueThis work evaluates the crucial characteristics of reliability for the proposed solar seed sowing machine using the Markov model which is a stochastic model. The assessment of reliability measures such as MTTF, availability and sensitivity plays a vital role in measuring and improving the performance of the machine in the actual environment. Examining the data obtained in this research is of great importance for the manufactures and system designers. Also, the powerful optimization technique PSO is implemented to solve a non-linear mixed-integer programming problem that provides the optimal cost for the system with desired reliability.

Low-frequency sound-absorbing metamaterial based on a series-parallel arrangement structure

Low-frequency noise has a long wavelength, decays very slowly, and is extremely penetrating. Traditional marine acoustic insulation materials have difficulty achieving effective control of this low-frequency noise. In this paper, a series-parallel arrangement structure of a low-frequency metamaterial is designed, which mainly comprises convoluted channels and Helmholtz cavities in series and a sandwich arrangement of multiple cells (as opposed to the traditional parallel arrangement). We use a numerical method to establish an acoustic-solid coupling model for the metamaterial, consider the influence of thermal and viscous losses on its sound absorption performance, and investigate the sound absorption characteristics and mechanisms of the single-cell and multicell structures. The metamaterial designed in this paper shows an average absorption coefficient of 0.97 in the range of 130–145 Hz. An experimental model was prepared by 3D printing, and the intended sound absorption effect was experimentally verified.

Equalization method of ‘LiCoxNiyMn1-x-yO2 - LiFePO4’ hybrid battery pack based on charging electric quantity estimation

Battery packs are typically composed of identical cells arranged in series-parallel arrangements, such as LiCoxNiyMn1-x-yO2 battery packs or LiFePO4 battery packs. To fully leverage the advantages of both LiCoxNiyMn1-x-yO2 cells and LiFePO4 cells, manufacturers have proposed an innovative scheme where the two types of cells are connected in series to form a hybrid battery pack. However, the electrical characteristics of the two cells differ significantly. As capacity degradation and self-discharge, the electrical quantity difference between the cells and the configuration of the hybrid battery pack will gradually change. Therefore, a dissipative cell equalization algorithm for the hybrid battery pack based on charging electric quantity estimation is proposed in this paper. The objective of the algorithm is to stabilize the energy output of the hybrid battery pack. We implement the proposed algorithm in simulations, containing a hybrid battery pack model. Dissipation cell equalization algorithm based on charging electric quantity estimation is proved to be effective by comparing the cell electric quantity difference with/without the algorithm. The relationship between cells in the pack with the visualization of equalization is further analyzed. Results demonstrate that closely match the theoretical values achieved through the dissipative equalization strategy after approximately 15 to 20 standard cycles, with a relative difference of no more than 1 % and minimal fluctuations. Therefore, the equalization method can change and recover the electric quantity difference, and achieve the energy stabilization strategy of the hybrid battery pack.

Stimulating green energy potential in Sub-Saharan Africa: An analysis of copper–copper sulphate thermogalvanic cell architecture

• Thermogalvanic cell architecture design is presented. • A maximum temperature difference of 70 °C is attainable in the attic of buildings. • The Highest Seebeck coefficient was obtained in 0.7 M CuSO 4 and 0.2 M H 2 SO 4 . • Maximum power of 26.12 nW/cm 2 is recorded. • Altering series–parallel arrangement increase power output of thermogalvanic cells. Solar energy has been of main interest with regard to renewable energy sources due to its abundance and immense potential. The conversion of low-grade solar energy into electricity by thermogalvanic cells has the potential to complement energy generation produced from fossil fuels in Sub-Saharan Africa. The main objective of this work is to design a thermogalvanic cell tailored for household applications using solar energy. A temperature profiling of a typical semi-detached building in Kumasi, Ghana was determined. The effect of temperature and H 2 SO 4 background electrolyte on the Seebeck coefficient and power output of Cu/CuSO 4 thermogalvanic cells were investigated. The study recorded the highest temperature difference of 70 °C in the attic of the building. The highest Seebeck coefficient (0.985 mV/K) was obtained at 0.7 M CuSO 4 + 0.2 M H 2 SO 4 electrolyte. The maximum power output derived from the experimental thermocell was 26.13nW/cm 2 . The design and simulation of the thermogalvanic cell architecture revealed that the thermocell can deliver a maximum current of 0.257 mA to a 1.2 V rechargeable battery.

An experimental and numerical evaluation of continuous pasteurization of açai pulp with plate heat exchangers on the inactivation of peroxidase and polyphenol oxidase

This work evaluates the thermal inactivation of peroxidase and polyphenol oxidase of açai-berry pulp in a continuous pasteurization using a lab-scale pasteurizer with plate heat exchangers (PHEs). Experiments were carried-out at three different açai flow rates with two different pass arrangements of the PHEs. The experimental treatments were simulated by CFD and the numerical results were compared to the experimental data. A better performance of the pasteurizer was noted when the PHEs were set in a series flow arrangement. Heating performance predicted by CFD satisfactorily agreed with the experimental data, especially when the PHEs were set in series flow. Conversely, reasonable deviations between numerical and experimental results of the residual activities of the enzymes occurred, mainly in a series-parallel flow arrangement. Accurately predicting inactivation of thermally-sensitive enzymes is quite difficult in the numerical simulation of complex processes and the reasons why these deviations occurred have been discussed. • HTST processing of açai pulp was evaluated in relation to POD and PPO inactivation. • Two countercurrent flow arrangements were evaluated in the plate heat exchangers. • Experimental and simulated results of temperature, POD, PPO activity were compared. • CFD showed a large potential in predicting enzyme inactivation in food processing.

Stability analysis and feedback design of a direct current–direct current power converter by vector Lyapunov function

SummaryTo prove the stability of hybrid systems, where, several subsystems are in series–parallel arrangement, Vector Lyapunov functions are appropriate substitutes for the scalar Lyapunov ones. By assigning a scalar Lyapunov function to each subsystem, the stability of the whole hybrid system can be analyzed. In this paper, having reviewed the preliminaries, a direct current (DC) –DC converter working as an incremental voltage source is selected. We show that the conditions of the vector Lyapunov stability are satisfied by deriving the variation interval for the feedback coefficients and obtaining the appropriate feedback factor given the desired output. Simplicity and less restrictedness of vector Lyapunov method is shown comparatively. All the derived mathematical relations are validated by numerical computations.

A Consensus Algorithm for Multi-Objective Battery Balancing

Batteries stacks are made of cells in certain series-parallel arrangements. Unfortunately, cell performance degrades over time in terms of capacity, internal resistance, or self-discharge rate. In addition, degradation rates are heterogeneous, leading to cell-to-cell variations. Balancing systems can be used to equalize those differences. Dissipative or non-dissipative systems, so-called passive or active balancing, can be used to equalize either voltage at end-of-charge, or state-of-charge (SOC) at all times. While passive balancing is broadly adopted by industry, active balancing has been mostly studied in academia. Beyond that, an emerging research field is multi-functional balancing, i.e., active balancing systems that pursue additional goals on top of SOC equalization, such as equalization of temperature, power capability, degradation rates, or losses minimization. Regardless of their functionality, balancing circuits are based either on centralized or decentralized control systems. Centralized control entails difficult expandability and single point of failure issues, while decentralized control has severe controllability limitations. As a shift in this paradigm, here we present for the first time a distributed multi-objective control algorithm, based on a multi-agent consensus algorithm. We implement and validate the control in simulations, considering an electro-thermal lithium-ion battery model and an electric vehicle model parameterized with experimental data. Our results show that our novel multi-functional balancing can enhance the performance of batteries with substantial cell-to-cell differences under the most demanding operating conditions, i.e., aggressive driving and DC fast charging (2C). Driving times are extended (>10%), charging times are reduced (>20%), maximum cell temperatures are decreased (>10 °C), temperature differences are lowered (~3 °C rms), and the occurrence of low voltage violations during driving is reduced (>5×), minimizing the need for power derating and enhancing the user experience. The algorithm is effective, scalable, flexible, and requires low implementation and tuning effort, resulting in an ideal candidate for industry adoption.

Backstepping Methodology to Troubleshoot Plant-Wide Batch Processes in Data-Rich Industrial Environments

Troubleshooting batch processes at a plant-wide level requires first finding the unit causing the fault, and then understanding why the fault occurs in that unit. Whereas in the literature case studies discussing the latter issue abound, little attention has been given so far to the former, which is complex for several reasons: the processing units are often operated in a non-sequential way, with unusual series-parallel arrangements; holding vessels may be required to compensate for lack of production capacity, and reacting phenomena can occur in these vessels; and the evidence of batch abnormality may be available only from the end unit and at the end of the production cycle. We propose a structured methodology to assist the troubleshooting of plant-wide batch processes in data-rich environments where multivariate statistical techniques can be exploited. Namely, we first analyze the last unit wherein the fault manifests itself, and we then step back across the units through the process flow diagram (according to the manufacturing recipe) until the fault cannot be detected by the available field sensors any more. That enables us to isolate the unit wherefrom the fault originates. Interrogation of multivariate statistical models for that unit coupled to engineering judgement allow identifying the most likely root cause of the fault. We apply the proposed methodology to troubleshoot a complex industrial batch process that manufactures a specialty chemical, where productivity was originally limited by unexplained variability of the final product quality. Correction of the fault allowed for a significant increase in productivity.

The hybrid RDWC–pervaporation with series–parallel arrangement and heat integration for ETBE production

A new process configuration consisting of hybrid reactive dividing wall column (RWDC)–pervaporation (PV) (with series–parallel arrangement) with feed splitting and heat integration was proposed to produce ETBE. To evaluate the performance of the proposed method, it should be compared with other ETBE production processes. A total of 12 ETBE production processes were optimized for this purpose. All process parameters were considered optimization variables. TAC was used as objective function, but all processes were also compared in terms of energy consumption. To reduce the energy cost in the PV process, heat integration between the internal RDWC flows and streams entering the PV modules was used to eliminate all heaters in the PV process and also the RDWC condenser. Feed splitting was used to reduce the heat duty of the RDWC reboiler. According to the results, the proposed method reduced the TAC by 59% and 36% respectively compared with the conventional processes and the RDWC. This TAC reduction in the hybrid RDWC–PV process relative to the RDWC can be related to a decrease in the number of trays in the main and prefractionator sections, elimination of the condenser and a significant reduction in the heat duty of the reboiler.

Optimization of triple-pressure combined-cycle power plants by generalized disjunctive programming and extrinsic functions

A new mathematical framework for optimal synthesis, design, and operation of triple-pressure steam-reheat combined-cycle power plants (CCPP) is presented. A superstructure-based representation of the process, which embeds a large number of candidate configurations, is first proposed. Then, a generalized disjunctive programming (GDP) mathematical model is derived from it. Series, parallel, and combined series-parallel arrangements of heat exchangers are simultaneously embedded. Extrinsic functions executed outside GAMS from dynamic-link libraries (DLL) are used to estimate the thermodynamic properties of the working fluids. As a main result, improved process configurations with respect to two reported reference cases were found. The total heat transfer areas calculated in this work are by around 15% and 26% lower than those corresponding to the reference cases.This paper contributes to the literature in two ways: (i) with a disjunctive optimization model of natural gas CCPP and the corresponding solution strategy, and (ii) with improved HRSG configurations.

A Study of Quantum Dots in a Multigrain Layer of a Planar-End Microstructure

Quantum dots (QDs) of CdSe, PbS, and InSb semiconductors in a multigrain layer of a planar-end microstructure have been studied. A model of an ordered QDs arrangement in a micron gap of the structure and a current flow along the lines of their series-parallel arrangement are considered. At low voltages (less than 8 V), electron transport is determined by thermal and tunnel emission from QDs into the gap, while at high voltages it is determined by charge restriction in QDs according to the model of Coulomb blockade. A strong effect of radiation with IR and UV spectra on the current–voltage characteristics has been found.

Incremento de la termotransferencia en un sistema de enfriadores enchaquetados, optimizando los flujos de agua

En esta investigación se propuso un esquema optimizado de distribución de agua para incrementar la termotransferencia, en un sistema de enfriadores de sulfuro de hidrógeno. La instalación está compuesta por dos intercambiadores de calor de tubos y coraza enchaquetados, instalados en un arreglo serie-paralelo. Cada equipo opera con tres fluidos y posee dos vías principales de intercambio térmico. La optimización de los flujos de agua se realizó mediante algoritmos genéticos, utilizando un modelo con base en el método ɛ-NUT para la simulación de los intercambiadores de calor. Se estimó un incremento del calor transferido entre 3695 y 10514 W, así como una disminución de la temperatura del gas a la salida del sistema entre 2.9 y 9.8 K. La recuperación termoenergética calculada osciló entre 3.90 y 22.16 %, con 12.44 % como promedio. Mediante regresión lineal múltiple se determinaron las funciones para solución tecnológica del problema investigado.

Optimum process configuration for ETBE production based on TAC minimization

A new process configuration consisting of hybrid pervaporation (PV) (with series–parallel arrangement and recycle streams)–distillation column (DC) or reactive distillation (RD) with a hybrid feed splitting-heat integrated distillation column (HIDiC) – heat integration method was proposed to produce ETBE. To evaluate the performance of the proposed method, 92 different processes for producing ETBE by RD columns, pressure swing distillation, PV, liquid–liquid extraction column or their combinations were optimized and compared to the new configuration. The PV modules were placed in four sections: before the column, next to distillate, next to bottom product and next to side stream. All process parameters in DC or RD, PV and heat integration were considered optimization variables, and all variables were simultaneously optimized by a hybrid GA–PSO algorithm. The proposed configuration reduced TAC by at least 30% and a maximum of 62% compared with other process configurations. This can be attributed to the use of PV instead of distillation columns, series–parallel arrangement instead of series and parallel arrangements in the PV process to reduce energy consumption and membrane area and also the use of heat integration between internal DC flows and PV streams to eliminate the need for hot utility.

Recovery of salinity gradient energy in desalination plants by reverse electrodialysis

Salinity gradient energy (SGE) capture by reverse electrodialysis (RED) is an emerging technology to advance the phaseout of conventional water-intensive energy sources in desalination industry. This paper assesses SGE recovery potential of an up-scaled RED system in seawater reverse osmosis (SWRO) desalination plants. Using a detailed RED system's model (i) we conducted a parametric evaluation of feed's concentration, feed's flow rate, and temperature to identify the optimal working conditions of an industrial-scale RED unit; (ii) we estimated SGE recovery of a RED plant in SWRO plants distributed worldwide, adopting a single-stage arrangement of the RED units; (iii) finally, to enhance energy yield, we examined different RED plant's layouts in a specific SWRO plant. The results underline the merits of this modelling tool to assist SGE-RED implementation in the utmost scenarios. Regarding RED plant's layout, findings reveal that the series-parallel arrangement of the RED units improves the power output and energy yield of the system but requires more RED units. Hence, a systematic evaluation through optimization of the hybrid process's configuration both at plant's scale and at RED unit's scale is needed to properly determine RED's SGE recovery potential from waste streams in SWRO plants.

Optimized Shelf-Stacked Paper Origami-Based Glucose Biofuel Cell with Immobilized Enzymes and a Mediator

Recently, as an efficient renewable power source, paper microfluidic enzymatic biofuel cells have received significant attention. Due to their inherent characteristics and outstanding performance, a microfluidic paper-based analytical device for enzymatic biofuel cells (μPAD-EBFCs) has emerged as the best alternative to conventional power supplies for various miniaturized devices. This work presents a novel, user-friendly, and cost-efficient enzyme and mediator-immobilized electrochemistry-based shelf-stack-configured μPAD-EBFC. This Y-shaped colaminar fluid-flow EBFC has been realized using multiwall carbon nanotube (MWCNT)-composed Bucky paper (BP) as a bioelectrode, where GOx (anodic enzyme) and laccase (cathodic enzyme) were immobilized with optimized chemistry. The potentiometric oxidation and reduction performances of fabricated bioelectrodes were characterized using different electrochemical techniques. Subsequently, four such Y-shaped μPAD-EBFCs were realized in a shelf-stack configuration using a mini-three-dimensional (3D) printed platform, where the μPAD-EBFCs were connected in various series–parallel arrangements. With such shelf-stack configurations, 4 series-connected μPAD-EBFCs delivered the maximum stable open circuit potential of 1.65 V, with a peak power density of 46.4 μW/cm² (58 μA/cm²) at 0.8 V. The generated output power is sufficient to power the small portable device, which can be easily and suitably tuned depending on the application.

Optimization and heat integration of hybrid R–HIDiC–PV process with the series–parallel arrangement of PV modules and recycle streams for TAME production

Tert–amyl methyl ether (TAME) production process is consisted of a reactor, a reactive distillation (RD) column and the methanol recovery section. The bottom product of the RD column is TAME while the distillate is consisted of the azeotropic mixture of methanol and isopentane (i-pentane) that can be separated by either the pervaporation (PV) membrane or conventional pressure swing distillation (PSD) and extractive distillation (ED) methods. The PV process allows the use of both series and parallel arrangements. The series arrangement has a lower membrane area compared to the parallel arrangement, while the parallel arrangement has a lower energy cost. A series–parallel arrangement with recycle streams was used in the present study to take advantage of both the series and parallel arrangements. The HIDiC method was used for reducing energy consumption in the RD column. Moreover, heat integration between PV streams and internal flows in the RD column was used to reduce PV energy consumption. The number of modules in each row, the recycle stream, the heat exchange ratio between the rectifying and stripping sections in the RD column and the heat exchange ratio between PV streams and internal RD streams were obtained by a hybrid GA–PSO algorithm. Furthermore, all RD and PV parameters were considered optimization variables and most importantly, all process variables were optimized simultaneously. According to the results, the proposed process reduced the total annual cost (TAC) by 52% and led to a 57% energetic gain compared to the conventional hybrid RD–PSD process. The proposed process also reduced TAC by 48% and led to a 40% energetic gain in comparison with the hybrid RD–PV process. This can be related to the reduced membrane area compared to the series and parallel arrangements as well as reduced energy costs of PV heaters through heat integration between PV steams and internal flows of the column.

Pneumatic system of a seeder with pneumatic sowing

The aim of the study is to develop a mathematical model of linear calculation of the pneumatic system of a seeder with a pneumatic sowing system, implemented in the MathCAD computer algebra system. The description of the pneumatic transport system of a typical seeder with pneumatic sowing is presented, its design scheme is given. Based on the provisions of the mechanics of continuous media, a methodology for calculating the parameters of a pneumatic system to verify the adopted design decisions has been developed. A computer model of a pneumatic transport system with series-parallel arrangement of sections has been developed. Linear calculations with structurally implemented recounting of indicators were performed. The obtained value of the standard deviation between the calculated average values and the velocities of the flow core in the sections does not exceed 14% for the values of the velocities and 0.5% for the pressure over the sections. When implementing the proposed analytical modeling in the MathCAD 8.0 system, the error in mass flow rate is 1.152×10-14%, which allows limiting the number of conversion cycles of indicators to two – three cycles.

Development of a complete cold electronic based discrete level sensor

A complete cold electronics based cryogenic level sensor with six discrete levels is presented here. Each level consists of a series arrangement of 3 diodes separated by 1 mm distance, forming a series-parallel diode arrangement. The method of feeding a constant current to only one selected level at a time has greatly improved the current requirement to (1-2mA). Likewise, multiplexing and monitoring the voltage across one level at a time using a cold electronics multiplexer circuit has negated the shortcoming of reduced sensitivity at higher number of levels. The level is determined by the series voltage of the diodes obtained from the output of op-amp circuit and corresponding to the delta diode voltage, digitization of the voltages has been done to represent immersed or exposed diodes in LN2. With this seriesparallel method of measurement, both the shortcomings of conventional diode based level sensors namely; requirement of large supply current for diodes and the thermal-voltage saturation error at higher levels are improved. Experimental results from the calibration are also presented here.

Ionic circuitry with nanofluidic diodes.

Ionic circuits composed of nanopores functionalized with polyelectrolyte chains can operate in aqueous solutions, thus allowing the control of electrical signals and information processing in physiological environments. We demonstrate experimentally and theoretically that different orientations of single-pore membranes with the same and opposite surface charges can operate reliably in series, parallel, and mixed series-parallel arrangements of two, three, and four nanofluidic diodes using schemes similar to those of solid-state electronics. We consider also different experimental procedures to externally tune the fixed charges of the molecular chains functionalized on the pore surface, showing that single-pore membranes can be used efficiently in ionic circuitry with distinct ionic environments.