Application Of Energy Technologies Research Articles

Rapid Melt-Quenching Enables General Synthesis of High-Loading Single-Atom Catalysts with Bicontinuous Nanoporous Structure.

Single-atom catalysts have attracted extensive attention due to their unique atomic structures and extraordinary activities in catalyzing chemical reactions. However, the lack of general and efficient approaches for producing high-density single atoms on suitably tailored supporting matrixes hinders their industrial applications. Here, a rapid melt-quenching strategy with high throughput to synthesize single atoms with high metal-atom loadings of up to 9.7 wt% or 2.6 at% on nanoporous metal compounds is reported, representing several-fold improvements compared to benchmarks in the literature. Mechanism characterizations reveal that the high-temperature melting provides the essential liquid environment and activation energy to achieve the atomization of metals, while the following rapid-quenching pins the isolated metal atoms and stabilizes the coordination environment. In comparison with carbon-supported single-atom catalysts, various collaboration combinations of single atoms and nanoporous metal compounds can be synthesized using the strategy, thus achieving efficient hydrazine oxidation-assisted H2 production. This synthesis protocol is highly compatible with automatic operation, which provides a feasible and general route to design and manufacture specific single-atom catalysts with tunable atomic metal components and supporting matrixes, thus promoting the deployment of single-atom catalysts for various energy technology applications.

Spectromicroscopy of Nanoscale Materials in the Tender X-Ray Regime Enabled by a High Efficient Multilayer-Based Grating Monochromator.

The combination of near edge X-ray absorption spectroscopy with nanoscale X-ray imaging is a powerful analytical tool for many applications in energy technologies, catalysis, which are critical to combat climate change, as well as microelectronics and life science. Materials from these scientific areas often contain key elements, such as Si, P, S, Y, Zr, Nb, and Mo as well as lanthanides, whose X-ray absorption edges lie in the so-called tender photon energy range 1.5-5.0keV. Neither conventional grazing incidence grating nor crystal monochromators have high transmission in this energy range, thereby yielding the tender photon energy gap. To close this gap, a monochromator setup based on a multilayer coated blazed plane grating and plane mirror is devised. The measurements show that this novel concept improves the photon flux in the tender X-ray regime by two-orders-of-magnitude enabling previously unattainable laboratory and synchrotron-based studies. This setup is applied to perform nanoscale spectromicroscopy studies. The high photon flux provides sufficient sensitivity to obtain the electronic structure of Mo in platinum-free MoNi4 nanoparticles for electrochemical energy conversion. Additionally, it is shown that the chemical bonding of nano-structures in integrated circuits can be distinguished by the electronic configuration at the Si-K edge.

Comprehensive analysis and evaluation of ship energy efficiency practices

The IMO is working to reduce emissions from ships. One of its initiatives is the Ship Energy Efficiency Management Program (SEEMP), which is based on the Plan, Do, Check and Act (PDCA) cycle. In order to clearly describe the weight of energy efficiency improvement methods in practice, current energy efficiency practices were summarised systematically from five aspects, including optimising navigational management and operation, improving power system efficiency, reducing ship resistance, improving company management as well as the application of new energy and new technologies. Based on the Fuzzy- Analytic hierarchy process (AHP) method, a multi-level evaluation system was established by considering the importance degree of these practices. Comprehensive evaluation was carried out in accordance with the results obtained from the questionnaire survey of experienced experts in China. The evaluation results show that the management innovation has higher influence than technological alteration in achieving the energy conservation and emissions reduction of ships, and the speed optimisation is recognised as the most effective approach onboard at present. The multi-attribute decision-making architecture and comprehensive evaluation method proposed is much needed by the ship managers and crew members to determine the best practice of energy efficiency.

Graphene-Based Metal-Organic Framework Hybrids for Applications in Catalysis, Environmental, and Energy Technologies.

Current energy and environmental challenges demand the development and design of multifunctional porous materials with tunable properties for catalysis, water purification, and energy conversion and storage. Because of their amenability to de novo reticular chemistry, metal-organic frameworks (MOFs) have become key materials in this area. However, their usefulness is often limited by low chemical stability, conductivity and inappropriate pore sizes. Conductive two-dimensional (2D) materials with robust structural skeletons and/or functionalized surfaces can form stabilizing interactions with MOF components, enabling the fabrication of MOF nanocomposites with tunable pore characteristics. Graphene and its functional derivatives are the largest class of 2D materials and possess remarkable compositional versatility, structural diversity, and controllable surface chemistry. Here, we critically review current knowledge concerning the growth, structure, and properties of graphene derivatives, MOFs, and their graphene@MOF composites as well as the associated structure-property-performance relationships. Synthetic strategies for preparing graphene@MOF composites and tuning their properties are also comprehensively reviewed together with their applications in gas storage/separation, water purification, catalysis (organo-, electro-, and photocatalysis), and electrochemical energy storage and conversion. Current challenges in the development of graphene@MOF hybrids and their practical applications are addressed, revealing areas for future investigation. We hope that this review will inspire further exploration of new graphene@MOF hybrids for energy, electronic, biomedical, and photocatalysis applications as well as studies on previously unreported properties of known hybrids to reveal potential "diamonds in the rough".

Topological defect and sp3/sp2 carbon interface derived from ZIF-8 with linker vacancies for oxygen reduction reaction

Defects in nanocarbon materials can trigger their intriguing electrochemical properties and potential applications, but their synthesis is challenging. Herein, we report the synthesis of ultrathin nitrogen-doped carbon nanosheets with intrinsic defects through the pyrolysis of ZIF-8 with linker vacancies. The as-synthesized electrocatalyst exhibits excellent oxygen reduction reaction (ORR) activity with an onset potential and half-wave potential of 1.05 and 0.873 V vs. RHE, respectively, outperforming the reported metal-free ORR electrocatalysts. It also shows a commercial Pt/C-comparable performance in zinc–air battery with a power density of 154.4 mW cm−2. Characterization and DFT calculation results suggest the adjacent sp3-carbon in carbon pentagon can significantly strengthen the adsorption and activation of oxygen molecules on sp2-carbon, hence the potential determining step is altered and ORR overpotential is lowered. This work highlights a promising green synthesis strategy of MOF-derived metal-free nanocarbon materials for wide application in advanced energy technologies.

Well-to-Wheel Analysis of Electric and Hydrogen Light Rail

The application of renewable energy technologies to rail transit should be evaluated on a comprehensive energy pathway efficiency basis to ensure that the renewable energy technology is truly beneficial. One such method is the well-to-wheel analysis method, which combines the energy efficiencies of each component of the energy pathway into a single energy efficiency value. The focus of this paper is on well-to-wheel analysis of electric and hydrogen light rail. The inefficiencies of the hydrogen train’s power plant and hydrogen production process are apparent in the hydrogen train’s well-to-wheel efficiency value of 16.6–19.6%. The electric train, due to improved pathway efficiencies, uses substantially less feedstock energy with a well-to-wheel efficiency value of 25.3%. While this result is specific to Charlotte, North Carolina, the electric train efficiency is influenced by the main source of electricity production—it is 24.6% in Cleveland, Ohio (coal heavy) and 50.3% in Portland, Oregon (hydroelectric heavy).

Effect and Mechanism of Economic Circulation in the Middle and Lower Reaches of the Yellow River: Multiregional Input–Output Model and Industrial Complex Network Approaches

China has implemented the Yellow River strategy, and the middle and lower reaches of the Yellow River (MLYR) play an important role in promoting the sustainable economic growth of China. However, the economic circulation of the MLYR is constricted by the imbalance and heterogeneity in the economy in the regions, and it is necessary to explore how economic circulation and sustainable development in the MLYR can be improved. In this study, based on the multiregional input–output tables for 2012 and 2017, we developed a MLYR multiregional input–output model; applied indicators, such as intraregional multiplier, interregional feedback, and spillover, to measure economic circulation effects; further developed the industrial circular network; and designed indicators of cycle length distribution, average cycle correlation, influence of the industrial cycle, and interactions of the weighted cycle to analyze the industrial circulation mechanism in the MLYR. We also analyzed the spatial and industrial structures of the economic circulation flows. The results show that economic linkages have been strengthened to a certain extent, but the imbalance in economic circulation is still prominent, and the imbalanced circular effects are determined by the characteristics of the cycles in the MLYR. The empirical findings contribute to several aspects of the theory of imbalanced economic development and provide an important perspective on, and feasible path for, achieving economic development. We suggest that policymakers should build a multi-dimensional innovation cooperation system, improve the digital connectivity of regions, and promote the green and low-carbon development of industry and the application of new energy technologies to achieve balanced, common, and sustainable economic development in the MLYR.

Research on Frequency Transmission Scheme of Wind Farm in the Scenario of DC Islanding

With the wide application of new energy technologies, wind power has become one of the technologies with the largest development scale. Voltage Source Converter based High Voltage Direct Current Transmission system has unique advantages in its active and reactive power decoupling control, etc., and has become the main solution to solve the wind power transmission of large-scale wind farms. This paper studies the control characteristics and basic principles of new energy generation in the passive transmission system of DC island power grids, and proposes a frequency signal transmission scheme in the external transmission scenario. The simulation results verify the feasibility of the frequency signal transmission scheme between the sending-end wind farm and the receiving-end power grid in the DC islanding scenario, and that the VSC-HVDC system can quickly provide active power support and improve the dynamic frequency stability of the interconnected system.

Growth chemistry of cobalt nitride by plasma enhanced atomic layer deposition

State-of-the-art atomic layer deposition (ALD) and photoemission characterisation are applied to grow and characterise cobalt nitride, a material that has applications in renewable energy and semiconductor technologies. The growth process is characterised using an in situ cycle-by-cycle methodology to identify the main factors which underpin optimal material growth. The role of co-reactant dosing and substrate temperature is analysed in detail to demonstrate the impact these parameters have on the overall composition of the film. The in situ approach, combined with high-energy synchrotron-based photoemission studies of the resulting films, enables understanding of the bulk chemical properties without need for physical removal of material by sputtering. The results provide an insight into optimising plasma assisted ALD processes for deposition of cobalt nitride, and strategies for minimizing carbon incorporation into the film from the precursor ligands.

Fluoropolymers and Their Nanohybrids As Energy Materials: Application to Fuel Cells and Energy Harvesting.

The current review article provides deep insight into the fluoropolymers and their applications in energy technology, especially in the field of energy harvesting and the development of fuel cell electrolyte polymeric membranes. Fluoropolymers have gained wide attention in the field of energy applications due to their versatile properties. The incorporation of nanofillers within the fluoropolymer to develop the nanohybrid results in an enhancement in the properties, like thermal, mechanical, gas permeation, different fuel cross-over phenomena through the membrane, hydrophilic/hydrophobic nature, ion transport, and piezo-electric properties for fabricating energy devices. The properties of nanohybrid materials/membranes are influenced by several factors, such as type of filler, their size, amount of filler, level of dispersion, surface acidity, shape, and formation of networking within the polymer matrix. Fluoropolymer-based nanohybrids have replaced several commercial materials due to their chemical inertness, better efficacy, and durability. The addition of certain electroactive fillers in the polymer matrix enhances the polar phase, which enhances the applicability of the hybrid for fuel cell and energy-harvesting applications. Poly(vinylidene fluoride) is one of the remarkable fluoropolymers in the field of energy applications such as fuel cell and piezoelectric energy harvesting. In the present review, a detailed discussion of the different kinds of nanofillers and their role in energy harvesting and fuel cell electrolyte membranes is projected.

Towards ultra-low energy consumption buildings: Implementation path strategy based on practical effects in China

The operational state of energy-efficient ultra-low energy consumption buildings is very important to achieve energy savings and emission reductions, which are currently necessary considerations for the development of the building industry. To date, studies on the implementation of ultra-low energy consumption have been based mainly on the analysis of the effects of certain technologies, and few studies have examined the regional implementation paths at different energy consumption levels. Based on an analysis of actual data obtained from energy consumption monitoring, verification of energy-saving renovations and green building evaluations in Chongqing, this paper suggests setting the target value for ultra-low energy consumption buildings in hot summers and cold winters areas at 29.04 kWh/(m2.a), proposes a technology system that includes the practical application of data for seven active energy-efficient technologies, and establishes an implementation path for the integrated application of active and renewable energy technologies. Then, a set of strategic models for the construction of implementation paths for ultra-low energy consumption buildings that can be promoted in different climatic areas and building types is proposed. The recommendations based on this model are of practical value for guiding policy makers in promoting the development of ultra-low energy consumption buildings.

Technical, economic, and environmental assessment of the distribution power system with the application of renewable energy technologies

Renewable energy technologies (RETs) have been universally accepted as the prospective choice to increase the reliability of the power system and reduce the effects of emission cost (EC), fuel cost (FC), maintenance cost (MC), power loss (PL), total annual cost (TAC) and voltage deviation (VD). The performance indicators are used in the study to assess the effects of diesel generator (DG), electric storage system (ESS), photovoltaic (PV) and wind turbine generator (WTG) on the environmental, economic, and technical performance of a microgrid system with modified Roy Billiton Test System (RBTS) bus 4 distribution network. The proposed model is utilized to achieve the goals of the study by minimizing the costs that are identified with the power outages, TAC, MC, EC, FC, PL, and VD of the system with the application of an intelligent optimal control method based on the fmincon solver. The outcomes of the study can be used as benchmarks to assess the cost-effectiveness of increasing the capacity of universal power supply and resolve the universal power crisis owing to the depletion of fossil fuels. The study provides vital information to enhance the efficiency of the power system and the guidelines to promote the development of sustainable energy.

Jet impingement cooling applications in solar energy technologies: Systematic literature review

• This study aims to fill a knowledge gap in the study of jet impingement patterns and trends. • It aims to provide new knowledge for future scientific endeavours by identifying empirical gaps. • In addition to identifying critical gaps in the literature, this systematic review serves as a foundation for future research in solar energy. • To assist researchers in identifying appropriate solar energy technologies, coolant types, and jet impingement methods for their studies. • This review is essential for determining appropriate research design and performance analysis. Recently, solar energy technologies have been advanced as they have the potential to replace fossil fuels in electricity generation. However, overheating and poor heat transfer within a solar collector are major problems in achieving high performance. Therefore, cooling applications must be used for solar technologies to increase the heat transfer rate to achieve better performance. Jet impingement cooling has been extremely successful in a variety of engineering and industrial applications. This research work aims to fill a knowledge gap in the field of jet impingement research patterns and trends in solar energy technology. A systematic analysis using the ROSES review approach found 32 relevant studies in the Scopus and Web of Science databases. After a thematic analysis, five main topics were selected to be discussed in this study: Solar Energy Technologies, Coolant Types, Jet Impingement Methods, Research Design, and Performance Analysis. The five themes consist of 22 subthemes. The study uncovered research gaps, highlighted research patterns, and revealed developments in jet impingement cooling applications in solar energy technologies. The areas and variables derived from the results of this study can provide additional knowledge for future academic endeavours and have filled empirical gaps in the topic studied. In addition, this systematic review study can provide relevant information to better understand on jet impingement cooling applications in solar energy technologies.

Modeling and Performance of a Buck Converter Based on ‘Fuzzy Logic Soft Computing Technique’ for Low Voltage Operations

This present paper details a ‘fuzzy logic soft computing technique’ of designing a controller for a buck converter operating at low voltages. The dc – dc buck converters find applications in solar energy technologies where they are used in solar control charging systems, battery charging systems, drones, in the automotive industry where there is integration of the engine and dc-dc motor drives resulting in hybrid electric drives or vehicle’s. Conventional controllers that is the proportional derivative control (pid) have dominated the control engineering field from the time of invention, however, these controllers present increased overshoot and a long time to achieve steady-state conditions. In this regard since fuzzy logic has intelligent capabilities, then a fuzzy logic soft computing-based controller is proposed in this paper. A mathematical analysis of the dc-dc buck design is also given and the modeling of the fuzzy logic control algorithms that avoids mathematical analysis is also discussed. Fuzzy control is one of the soft computing tools that consists of the observation made by people and their decision based on non-numerical information is also discussed. The performance analysis of the fuzzy controller is determined under constant load and variable decreasing voltage conditions. The analysis and simulation of the dynamic response in closed-loop frequency response are conducted in the Simulink platform in Matlab. The proposition of control is executed on a dc-dc step down converter for an input of 12V. This proposed fuzzy logic control technique provides a dc – dc buck converter system with increased overall operating efficiency and a very stable output.

Atomistic simulations of hydrogen distribution in Fe–C steels

To engineer low-cost Fe–C based steels for application in hydrogen energy technologies, an understanding of the hydrogen distribution inside the material and how it is affected by the microstructure is vital. Molecular statics and molecular dynamics simulations are used to study hydrogen distribution and transport kinetics in the ferritic and martensitic phases of Fe–C steels, with and without dislocations present. We find that hydrogen preferentially resides in martensite especially in high dislocation density regions near the martensite/ferrite boundaries, in agreement with experiments. Furthermore, the rate of hydrogen transport through ferrite is up to an order of magnitude greater than that in martensite. The fundamental mechanisms behind this phenomenon are analyzed.

In-situ Raman investigation and application of phenazine-based organic electrode in aqueous proton batteries

Aqueous proton batteries (APBs) have aroused attention because of the proton as charge carrier with smaller ionic size and faster kinetics when compared to the metallic ions in aqueous solutions. Although phenazine-based organic compounds with available redox-active sites are considered as promising organic electrode materials, the comprehensive study of their proton-storage behaviors and APB applications is still lacking so far. Herein, a rod-like diquinoxalino-phenazine (DPZ) organic compound is designed and synthetized via a facile dehydration approach. In-situ Raman investigation and theoretical calculation are conducted to probe into the proton redox process of DPZ organic electrode for the first time. It is demonstrated that three CN electroactive regions in each DPZ molecular unit could be simultaneously coordinated with two protons and the redox reaction between CN and CN bonds is highly reversible upon proton insertion/extraction. As expected, the DPZ organic electrode delivers a large proton-storage capacity of ∼ 218 mAh/g and long-term cycle performance without obvious dissolubility in acidic aqueous electrolyte. For real applications, soft-package and wire-shaped APBs based on such DPZ organic electrode are constructed, and they both achieve outstanding electrochemical characteristics, revealing their great potential applications in low-cost, high-safety, and high-performance energy technologies and portable/wearable electronics.

XOR data envelopment analysis and its application to renewable energy sector

The conventional data envelopment analysis (DEA) method suffers from its inability to incorporate the decision-makers’ preferences and cope with the uncertainty that exists in real-life decision problems. Exclusive-or (XOR for short) is an uncertain logic that describes a situation in which there is only one choice between two or more competitive actions and neither is strong enough to overcome the others. In this paper, a new research thread of the DEA paradigm, named XOR-DEA, is proposed to deal with decision-making problems under xorness (or XOR input/output data). To incorporate decision-makers’ preferences in the optimization process, three types of preferences are proposed: positive, negative, and neutral. To cope deeply with uncertainty, a new concept of “the output mechanism of the XOR function” is developed to support the analyst in controlling this phenomenon based on two channels: controlled and uncontrolled. Moreover, to enrich the analysis of practical applications, a new visual analytic material is designed to detect the behavior of the XOR functions during the optimization process. To show the models’ applicability, an illustrative example and an application of ranking renewable energy technologies are presented.

Awareness Enhancement on Atomic Energy and Nuclear Technology Applications Using ICT

Purpose: There have been a lot of applications of atomic energy and nuclear technology in different development activities in Tanzania but it seems that people are not aware of this. On the other hand, ICT has been reported to enhance the awareness of various issues. It is not known how much ICT takes a role in enhancing the awareness of atomic energy and nuclear applications in Tanzania. This study therefore aimed at uncovering the role of ICT in enhancing awareness of atomic energy and nuclear technology applications in Tanzania. 
 Design/Methodology/Approach: The study used a quantitative method whereby a five scale Likert-scale questionnaire was used to collect data from higher education students and the public. The descriptive statistics and a t-test were used as part of the analysis of the findings. 
 Findings: The results show that generally, most students and people from the public are not aware of the applications of nuclear technology in Tanzania (Mean: 3.18) and most of them (Mean: 3.42) have not been using ICT to get information on nuclear technology application in Tanzania. It was also found that there is a significant difference (p<0.05) between students and the public in both awareness and perception of the use of ICT to increase awareness with a small effect (0.2<d<0.5). 
 Implications/Research Limitations: The study involved university/college students in all fields and also the people from the public from any field and any study level; which may call for more studies on more specific groups. The study focused on Tanzania which may be limited to the environment present.
 Practical Implication: This study is useful in the process of taking necessary measures on increasing awareness among Tanzanians and especially students who can be the future experts in the field of nuclear technology.

Controlling Symmetry Breaking Charge Transfer in BODIPY Pairs.

Symmetry breaking charge transfer (SBCT) is a process in which a pair of identical chromophores absorb a photon and use its energy to transfer an electron from one chromophore to the other, breaking the symmetry of the chromophore pair. This excited state phenomenon is observed in photosynthetic organisms where it enables efficient formation of separated charges that ultimately catalyze biosynthesis. SBCT has also been proposed as a means for developing photovoltaics and photocatalytic systems that operate with minimal energy loss. It is known that SBCT in both biological and artificial systems is in part made possible by the local environment in which it occurs, which can move to stabilize the asymmetric SBCT state. However, how environmental degrees of freedom act in concert with steric and structural constraints placed on a chromophore pair to dictate its ability to generate long-lived charge pairs via SBCT remain open topics of investigation.In this Account, we compare a broad series of dipyrrin dimers that are linked by distinct bridging groups to discern how the spatial separation and mutual orientation of linked chromophores and the structural flexibility of their linker each impact SBCT efficiency. Across this material set, we observe a general trend that SBCT is accelerated as the spatial separation between dimer chromophores decreases, consistent with the expectation that the electronic coupling between these units varies exponentially with their separation. However, one key observation is that the rate of charge recombination following SBCT was found to slow with decreasing interchromophore separation, rather than speed up. This stems from an enhancement of the dimer's structural rigidity due to increasing steric repulsion as the length of their linker shrinks. This rigidity further inhibits charge recombination in systems where symmetry has already enforced zero HOMO-LUMO overlap. Additionally, for the forward transfer, the active torsion is shown to increase LUMO-LUMO coupling, allowing for faster SBCT within bridging groups.By understanding trends for how rates of SBCT and charge recombination depend on a dimer's internal structure and its environment, we identify design guidelines for creating artificial systems for driving sustained light-induced charge separation. Such systems can find application in solar energy technologies and photocatalytic applications and can serve as a model for light-induced charge separation in biological systems.

Optimal Design and Techno-Economic Analysis of a Grid-Connected Photovoltaic and Battery Hybrid Energy System

The application of green energy technologies (GETs) has been accepted universally due to the industrial revolution, increasing energy demand, high standard of living, population growth and fluctuation of crude oil prices. In view of this, GETs have been recognized on a global note as a promising and significant alternative to meet ever increasing power demand. This research work is aimed at optimal operation and design of hybrid renewable energy system (HRES) to enhance the performance of the power system while taking into consideration the energy produced, levelized cost of energy (LCOE), return on investment (ROI), solar fraction (SF), net present value (NPV), payback period and saved CO2 emissions based on the photovoltaic (PV) orientation. This is due to the fact that the solar panel generates more electrical output when its surface is perpendicular to the solar radiation. The PV orientation significantly affects the output of a solar farm, for this reason, fixed tilted plane, vertical axis tracking system and two axes tracking system are proposed in this research work to estimate their effects on the technical, economic and environmental performance of HRES. This paper presents a grid-connected HRES that comprises utility grid, PV, battery system (BS) and load. The modelling and simulation of HRES are implemented by using PVsyst.7 energy tools in conjunction with the meteorological data made available by the National Aeronautics and Space Administration (NASA). The research outputs show that the two axes tracking system is more techno-economic feasible when compared with the fixed tilted plane and vertical axis tracking system based on the following results: Energy obtained from the grid of 4.657 MW/yr, LCOE of 0.075 ZAR/kWh, ROI of 862.7%, SF of 0.6781, NPV of 828,881.74 ZAR, payback period of 3.5 years and carbon balance of 732.240 tons. The outcomes of the study can be used by the power system planners and designers as benchmarks to utilize the prospect of solar resources for power sector reform and the industrial revolution.