Optimum Design Considerations Research Articles

An overview of the existing and future state of the art advancement of hybrid energy systems based on PV-solar and wind

Abstract Increasing solar and wind power use in existing power systems could create significant technical issues, especially for grids with poor connectivity or stand-alone systems needing more adequate storage capacity. This is due to the unpredictable and intermittent nature of solar and wind power. The intermittent nature of solar and wind resources can be reduced by integrating them optimally, making the entire system more reliable and cost-effective to operate. The advantages and disadvantages of hybrid wind and solar energy integration systems are discussed in this research. The impact of voltage and frequency oscillations and harmonics is amplified in weak grids, affecting both grid-connected and stand-alone systems. This may be fixed by ensuring that hybrid systems are well designed, equipped with cutting-edge quick reaction control capabilities, and optimized. This review offers an overview of existing advances in PV-solar and wind-based hybrid energy systems while exploring potential future developments. Further, this review also provides an overview of the primary studies published on optimum design considerations for compactness, topologies for power electronics, and control. As the global energy environment shifts toward sustainability and resilience, this review helps researchers, policymakers, and industry stakeholders understand, adapt, and enhance PV-solar-wind hybrid energy systems.

Productive and Sustainable H2 Production from Waste Aluminum Using Copper Oxides-Based Graphene Nanocatalysts: A Techno-Economic Analysis

Hydrogen has universally been considered a reliable source of future clean energy. Its energy conversion, processing, transportation, and storage are techno-economically promising for sustainable energy. This study attempts to maximize the production of H2 energy using nanocatalysts from waste aluminum chips, an abundant metal that is considered a potential storage tank of H2 energy with high energy density. The present study indicates that the use of waste aluminum chips in the production of H2 gas will be free of cost since the reaction by-product, Al2O3, is denser and can be sold at a higher price than the raw materials, which makes the production cost more efficient and feasible. The current framework investigates seven different copper oxide-based graphene nanocomposites that are synthesized by utilizing green methods and that are well-characterized in terms of their structural, morphological, and surface properties. Reduced graphene oxide (rGO) and multi-layer graphene (MLG) are used as graphene substrates for CuO and Cu2O NPs, respectively. These graphene materials exhibited extraordinary catalytic activity, while their copper oxide composites exhibited a complete reaction with feasible techno-economic production. The results revealed that the H2 production yield and rates increased twofold with the use of these nanocatalysts. The present study recommends the optimum reactor design considerations and reaction parameters that minimize water vaporization in the reaction and suggests practical solutions to quantify and separate it. Furthermore, the present study affords an economic feasibility approach to producing H2 gas that is competitive and efficient. The cost of producing 1 kg of H2 gas from waste aluminum chips is USD 6.70, which is both economically feasible and technically applicable. The unit cost of H2 gas can be steeply reduced by building large-scale plants offering mass production. Finally, the predicted approach is applicable in large, medium, and small cities that can collect industrial waste aluminum in bulk to generate large-scale energy units.

Optimum design considerations for CW intra-cavity second harmonic generation in end-pumped solid-state lasers

An understanding of performance of a laser system in terms of design parameters is of the great importance to the engineer who is designing a laser system. This manuscript describes a theoretical report on the optimum design key parameters of an intracavity frequency doubled end-pumped solid-state laser based on the combination of space-dependent rate equations and nonlinear coupled-wave analysis of second-harmonic generation. The theoretical framework along with the results presenting the effect of various parameters such as pump beam characteristics, gain medium and nonlinear crystal properties to optimize the SHG efficiency has been investigated. By considering the optimized root mean square of pump beam radius as the effective value of pump spot size in the gain medium and perfect phase matching between fundamental and second harmonic waves,optimum nonlinear crystal's length, optimum mode size and second harmonic output power are derived as a function of pump-beam characteristics, and properties of the nonlinear and gain medium crystals. The results show that the optimum nonlinear crystal's length depends not only on the nonlinear coefficient and spot radius of laser beam but also on the pump beam properties and gain medium characteristic. In addition, the effect of pump and gain medium properties on the optimal fundamental beam by taking into account thermal aberration are investigated. The obtained results give useful guidelines for choosing the suitable active and nonlinear crystals for a given pump source and allow the straightforward evaluation of laser parameters for efficient intracavity doubling in end-pumped solid-state lasers.

Photovoltaic DC-Building-Module-Based BIPV System—Concept and Design Considerations

The photovoltaic (PV) modules used in the building-integrated PV (BIPV) system, generally, can be installed in different orientations and angles. Moreover, performance of the PV modules is easy to be affected by partial shadows and mismatch of their electrical parameters. Consequently, the conventional power configurations are difficult to obtain higher energy efficiency and reliability. Some improved power configurations of BIPV system have been presented to solve these problems. The objective of the paper is to give an overview of the existing solutions, and then, proposes an efficient and cost-effective power configuration of BIPV system from the energy conversion and control point of view. The proposed power configuration consists of plenty of PV dc-building module (PV-DCBM) and a centralized inverter. Each PV-DCBM includes a high step-up dc-dc converter integrated with a PV module into an individual electrical device. The PV-DCBMs are parallel connected, and then, connected to a common dc bus. The centralized inverter is connected to the grid. The design criterions, optimum design considerations, and design procedure of the proposed PV-DCBM-based BIPV system are proposed in this paper. The experimental results are presented to verify the validity and feasibility of the novel concept.

Optimum design consideration for interferometric spin wave logic operations

In the present study, the operational modes and the structural design are optimized to realize potential performance in the interferometric spin wave logic circuits. Successive functional operations, such as generation, propagation, and inductive detection of spin wave packets are numerically studied by using micromagnetic simulations. The logic input is coded with the phase of pulsed microwave currents applied through the generators. Among the various kinds of the investigated spin wave (SW) modes, the backward volume mode exhibits superior performance. Various structural and operational parameters, including the pulsed microwave frequency and the film thickness of the magnetic strip, were optimized by taking the inductive output voltage (Vout) as a quantitative criterion. The several orders of difference obtained in the Vout for the different logic inputs demonstrates the successful exclusive-not-OR operation.

Interface Characterization and Electrical Transport Mechanisms in a-Si:H/c-Si Heterojunction Solar Cells

The fabrication of amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction solar cell and an understanding of the fundamental conduction mechanism in the device are presented. In the first part, the effect of intrinsic amorphous silicon [a-Si:H(i)] layer thickness on the performance of a-Si:H/c-Si solar cells has been studied. The thickness of a-Si:H(i) layer formed on n-type c-Si substrate was controlled accurately with spectroscopy ellipsometry (SE). Based on SE results, we discuss the influence of the a-Si:H(i) thickness on the interface quality and thereby cell performance. Then, in the latter part, we present the temperature-dependent current density–voltage curves, in the dark, in order to elucidate the dominant transport mechanisms in a-Si:H/c-Si heterojunction solar cells with and without incorporation of a-Si:H(i) layers. Finally, using optimum design considerations, we obtained a solar cell efficiency of 17.43%.

Optimum Design Consideration and Implementation of a Novel Synchronous Rectified Soft-Switched Phase-Shift Full-Bridge Converter for Low-Output-Voltage High-Output-Current Applications

Optimum design consideration and implementation of a novel synchronous rectified soft-switched phase-shift full-bridge dc/dc converter with a primary-side energy storage inductor for server adapter application is presented in this paper. By employing a primary-side energy storage inductor, the main switches can achieve a soft-switching condition, and there is little reverse recovery loss in the body diodes of a secondary-side rectifier due to relatively slow downslope of the triangular current. Since the output capacitive filter reduces the voltage stress across the rectifiers, the synchronous rectifier with a lower breakdown voltage rate can be utilized to improve the conversion efficiency dramatically. Thus, this converter can obtain relatively high conversion efficiency for some medium-power applications with low output voltage and high output current, such as the server adapter. Several key optimum design considerations of this converter are also presented in detail in this paper. Finally, a 100-kHz, 300-W (12 V/25 A) laboratory-made prototype for a given server adapter application is built up based on the proposed optimum design procedure of this converter to verify all the theoretical analysis and evaluations.

A review and assessment of hydrodynamic cavitation as a technology for the future

In the present work, the current status of the hydrodynamic cavitation reactors has been reviewed discussing the bubble dynamics analysis, optimum design considerations, design correlations for cavitational intensity (in terms of collapse pressure)/cavitational yield and different successful chemical synthesis applications clearly illustrating the utility of these types of reactors. The theoretical discussion based on the modeling of the bubble dynamics equations aims at understanding the design information related to the dependency of the cavitational intensity on the operating parameters and recommendations have been made for the choice of the optimized conditions of operating parameters. The design information based on the theoretical analysis has also been supported with some experimental illustrations concentrating on the chemical synthesis applications. Assessment of the hydrodynamic cavitation reactors and comparison with the sonochemical reactors has been done by citing the different industrially important reactions (oxidation of toluene, o-xylene, m-xylene, p-xylene, mesitylene, o-nitrotoluene, p-nitrotoluene, m-nitrotoluene, o-chlorotoluene and p-chlorotoulene, and trans-esterification reaction i.e., synthesis of bio-diesel). Some recommendations have also been made for the future work to be carried out as well as the choice of the operating conditions for realizing the dream of industrial scale applications of the cavitational reactors.

An analysis of an endoreversible heat engine with combined heat transfer

The power optimization of an endoreversible heat engine has been performed, and design characteristics have been described at maximum-power conditions. A technologically important example defined as heat exchange by combined radiation and convection has been considered. The analysis shows that the maximum power output of the heat engine is sensitive to the temperature, small values of the ratio of convective heat transfer coefficients of hot to cold ends and small values of the emittance ratio of heat source to heat sink. By considering the output power, and must be held around 0.2, 0.01 and 0.0125 for optimum design considerations, respectively.

Optimum design considerations for silicon piezoresistive pressure sensors

Optimum design considerations for silicon piezoresistive pressure sensors are carried out on the basis of the design restriction release produced by recent progress in microwave plasma etching technology. The optimum shape and plane of a diaphragm and the optimum direction of gauges are analysed by taking into account the effects of anisotropy of the piezoresistivity and elasticity and large deflection of diaphragms. A new index η, which expresses the relative performance of sensors, is introduced for the optimal gauge direction on the optimal diaphragm plane. It is found that the optimum design is as follows: four gauges are aligned on a 〈111〉 direction on a {110} plane square diaphragm with a centre boss.

Theoretical studies of the optimum design considerations in ring dye laser

The theoretical studies of the optimum geometrical design considerations in the ring resonator of the dye laser are studied. The position of the minimum waists and the range of stabilisation parameters using the optical matrices are calculated. The design considerations of the high passive stability, and low optical losses are discussed. Additionally, a single-mode, broad-band and low-loss ring laser resonator of length 600 mm, using a minimum number of optical elements is reported.

Optimum design considerations for mechanically fastened composite joints

Various parameters amenable to the optimum design of mechanically fastened composite joints are identified. These are categorised into three groups denoted material, fastener and design. Particular emphasis is directed towards a new semi-empirical technique formulated to predict the strength of both pinned and bolted composite joints. The results show excellent agreement with previously published experimental data.

Optimum Design of a Low-Pressure, Double Inflow, Radial Steam Turbine for Open-Cycle Ocean Thermal Energy Conversion

This paper describes the thermo-fluid design concept of a low-pressure, radial inflow steam turbine for the Open-Cycle Ocean Thermal Energy Conversion (OTEC). For the optimum design consideration, the necessary theoretical tools are developed. The design concept permits the utilization of single-stage and multistage configurations for small and medium power ranges, respectively.

Buckling behavior of an underwater storage vessel

Optimum design considerations for an underwater storage vessel to contain liquid gases and oils led to the assessment of an axisymmetric shell of revolution—the Echinodome or drop shape. Analytical treatment of the various types of loading to which the shell could be subjected indicated that buckling was the more critical design criteria.

Optimum design considerations for dual conductor bubble devices

A design for dual conductor, current-access bubble devices with 8-μm periods has been optimized with a numerical calculation method for bubble motion in a propagating magnetic field, generated around hole patterns in conductor layers. Magnetic bias field distributions are calculated for an oval hole chain in the conductor layers. Bubble motion equations are obtained with analytical field distribution functions approximating the calculated field distributions. Minimum drive current density J min for normal bubble propagation is determined by a solution to the equations. The hole shape has been optimized by the minimization of the drive power P min , the product of J min and conductor resistance, which is calculated from current distributions around the hole pattern. Optimum layer thickness have also been obtained for 8-μm period bubble devices. Both registration tolerance between the two conductor layers and bubble skew effects have been studied semiquantitatively on the basis of the equations of motion. The numerical calculation method developed here is found to be a highly effective means to optimize pattern design for smaller period devices.

Optimum design considerations for silicon pressure sensor using a four-terminal gauge

Optimum design considerations are presented for circular and square diaphragms on (100) and (110) crystal planes with p- and n-type four- terminal gauges in place of the conventional Wheatstone bridge construction Maximum output is obtained at the (100) circular diaphragm edge with a p- type gauge along a (011) direction at an angle of 45° The maximum output voltage of the circular diaphragm is 2 4 times as large as that of the square diaphragm It is found that the output voltage depends only on shear stress T` xy V out≌(ω/ɭ)π 66T` xyV s where V s is the supplied voltage, ω is the width of the gauge, ɭ is the length and π 66 is the piezoresistance coefficient

OPTIMUM DESIGN OF CURRENT-COMPOUNDED VOLTAGE REGULATORS

ABSTRACT Current-compounded excitation circuits will regulate the terminal voltage of isolated synchronous generators, typically to within ± 3% of the nominal value, throughout the rated range of load current and power factor. By investigating the VA rating of the components involved, the paper shows that their weight and cost can be minimised, and an optimum regulator design thereby achieved. Graphical results for a range of generator parameters are presented for use in optimum design considerations

A new type of pressure sensor utilizing surface acoustic waves

Abstract Mechanical strain effect experiments on a 103 MHz Y-Z LiNbO3 surface acoustic waves (SAW) transducer with 3 cm electrode distance have been made. The phase shift was 40 degrees at −90 × 10−6 strain and quite linear with strain. Optimum design considerations for a SAW pressure sensor consisting of a clamped edge piezoelectric diaphragm with two sets of interdigital electrodes have been made. The optimum positions for the electrodes were determined. Deflection of the diaphragm under pressure retards the phase for one set and advances the phase for the other set. The maximum phase shift and cancellation of thermal expansion effects results by measuring the phase difference between the two sets. The maximum phase shift and cancellation of thermal expansion effects results by measuring the phase difference between the two sets.

Broadband Acoustooptic Deflectors: New Results

A new broadband acoustooptic (AO) Bragg deflector using acoustic beam steering to track the Bragg angle is described. It features, instead of the conventional stepped array acoustic grating to produce the steering sound column, a flat transducer grating made from a single piezoelectric platelet bonded to the AO medium, with the spatially periodic phase variations created by interdigitating the electrode configuration. The advantage over the conventional stepped array, for deflectors operating at frequencies above 100 MHz, is the ease of fabrication of the device, an advantage that far outweighs its somewhat reduced acoustic power available for light diffraction. An analysis is presented to show that the achievable half-power bandwidth from beam steering deflectors under optimum design considerations is over four times the bandwidth of fixed beam deflectors having the same transducer dimensions. Experimental results on lead molybdate deflectors confirm the predicted fourfold improvement.

Optimum Design Considerations for Traction-Motor Commutators

The dc traction motor, an integral part of a diesel electric locomotive operation, depends on the commutation of current for satisfactory operation. Increasing demands for power and speed from traction motors, together with environmental conditions associated with their operation, necessitated rigid parameters for improving manufacturing techniques and materials to provide successful commutators for this service.