Energy Flow Diagrams Research Articles

Analysis of Energy Flow to the Interface Microstructure and Its Effect on Weld Strength in Ultrasonic Additive Manufacturing

Ultrasonic additive manufacturing (UAM) is a process used for the three-dimensional printing of metal foil stock that can produce near-net-shaped metallic parts. This work details the development of an energy-based tool to identify the relationships between input energy, energy stored in the interface microstructure, and the strength of the weld interface in UAM. The stored energy in the grain boundaries of the crystallized grains in the interface microstructure are estimated using the Read–Shockley relationship. The energy stored in the interface is found to be positively correlated with the resulting weld strength. An energy flow diagram is developed to map the flow of energy from the welder to the workpiece and quantify the key participating energies such as the energy of plastic deformation, energy stored in the interface microstructure, energy required for asperity collapse, and heat generation. A better understanding of the flow of energy in UAM can assist in optimizing the process to maximize the portion of energy input by the welder that is used for bond formation.

Enhancing Ultrasound Power Transfer: Efficiency, Acoustics, and Future Directions.

Implantable medical devices (IMDs), like pacemakers regulating heart rhythm or deep brain stimulators treating neurological disorders, revolutionize healthcare. However, limited battery life necessitates frequent surgeries for replacements. Ultrasound power transfer (UPT) emerges as a promising solution for sustainable IMD operation. Current research prioritizes implantable materials, with less emphasis on sound field analysis and maximizing energy transfer during wireless power delivery. This review addresses this gap. A comprehensive analysis of UPT technology, examining cutting-edge system designs, particularly in power supply and efficiency is provided. The review critically examines existing efficiency models, summarizing the key parameters influencing energy transmission in UPT systems. For the first time, an energy flow diagram of a general UPT system is proposed to offer insights into the overall functioning. Additionally, the review explores the development stages of UPT technology, showcasing representative designs and applications. The remaining challenges, future directions, and exciting opportunities associated with UPT are discussed. By highlighting the importance of sustainable IMDs with advanced functions like biosensing and closed-loop drug delivery, as well as UPT's potential, this review aims to inspire further research and advancements in this promising field.

Potential utilization of hydrogen in the UAE's industrial sector

Climate change and resource depletion pose significant challenges to global sustainable development. In the United Arab Emirates (UAE), the industrial sector contributes to over half of the total final energy consumption, resulting in substantial carbon emissions. This study addresses how hydrogen, as an energy carrier, can facilitate the integration of renewable energy in hard-to-abate industries. We explore the energy landscape by analyzing energy flow diagrams, emission trends, and the social cost of carbon in the UAE. We propose a Green-to-Green system framework that promotes sustainability and incorporates the Power-to-X (PtX) concept, with hydrogen playing a central role. Our findings indicate that decarbonizing industries solely through renewable energy encounter challenges. However, domestically adopting solar PV for green hydrogen production presents an opportunity to decarbonize hard-to-abate industries. Furthermore, we emphasize the importance of a national hydrogen strategy to advance hydrogen utilization in the industrial sector.

Optimizing Device Performance of Multi-Pass Flat-Plate Solar Air Heaters on Various Recycling Configurations

Various external-recycle configurations of multi-pass flat-plate solar air collectors were studied theoretically to examine the optimal thermal performance under the same working dimension and operation conditions. An absorber plate and insulation sheet were implemented horizontally and vertically, respectively, into an open rectangular conduit to conduct a recycling four-pass operation, which the device lengthens the air flow channel and increases the air mass flow rate within the collector, and thus, a more heat transfer efficiency is obtained. Four recycling types with different external-recycle patterns were introduced and expected to augment the heat transfer rate due to the turbulent convective intensity through four subchannels in the present study. Coupling energy balances into one-dimensional modeling equations were derived by making the energy-flow diagram within a finite element, which the longitudinal temperature distributions for each subchannel were obtained. The theoretical predictions show that the improved four-pass device is accomplished due to the multiple heating pathways over and under the absorber plate, from which the turbulence intensity augmentation results in the heat transfer rate as compared to that in the device without inserting the absorber plate and insulation sheet (say a downward-type single-pass solar air collector). The theoretical results also show that the external-recycle configuration (say Type C in the present study) acts as an optimal collector thermal efficiency and leading to a beneficial design in multi-pass solar air collectors for improving heat-transfer rate and increasing resident time under the same operation conditions. Theoretical predictions show a higher heat-transfer efficiency for the present recycling configurations up to a maximum 115% device enhancement in comparison to that of a single-pass device. Examination of implementing the absorber plate and insulation sheet on the heat-transfer efficiency enhancement as well as the hydraulic dissipated power increment were also delineated, and deliberated the suitable external-recycle configuration with respect to an economic consideration.

Classification for the Concrete Syntax of Graph-Like Modeling Languages

A classification scheme for Graph-Like Modeling Languages (GLML) is presented in this paper. The novelty of this classifier lies in its application to a meta-model for GLML that deviates from the simple graph model and underlies a large number of GLML. The main goal of using this classification scheme is to support the reuse of layout algorithms for GLML. GLML are used directly or indirectly for the development of software by model-based software engineering techniques. In other domains, graph-like models are artifacts (e.g., circuit diagrams, energy flow diagrams) that serve as input for downstream specialized applications (simulators, optimizers). The concrete syntax of a language for creating, editing, and understanding models is highly important for the development of modeling tools. Layout methods for the used languages have to be implemented to achieve software tools with good usability. Developing layout algorithms is a complex topic that is covered by the specialized field of Graph Drawing. However, there is no existing procedure to determine which layout algorithm can be used for a GLML. Matching layout algorithms to GLML can be achieved by applying the presented classification scheme.

Control-oriented dynamic modeling and thermodynamic analysis of solid oxide electrolysis system

Solid oxide electrolysis cell (SOEC) is a potential technology for increasing renewable energy penetration by turning excess power into hydrogen-based chemical energy, due to its high efficiency. In light of the intermittency of renewable energy, SOEC has to operate in a dynamic-changing environment. Therefore, dynamic modeling and thermodynamic analysis of solid oxide electrolysis systems are crucial for control design and efficient operation. In order to address various voltage losses, this paper develops a dynamic model of the solid oxide electrolysis system, in which the stack voltage is derived based on the electrochemical mechanism. The stack temperature is described by considering the dynamics of convective and radiative heat transfer between the layers. Dynamics of balance of plant (BOP) are modeled based on the mass and energy conservation laws. The model accuracy is verified by the polarization curve under different temperatures. The effects of temperature and current density on the electrolytic voltage are discussed. Three different operation modes (endothermic, thermoneutral and exothermic) are discussed in terms of different current density regions, where the balance between the electrochemical loss and reaction heat consumption varies. Steady-state energy and exergy flow diagrams are used to compare the energy consumption of different components in terms of different inlet temperatures, aiming to determine the optimal conditions with maximum system efficiency. The electrolyzer is revealed as the component with the highest energy consumption and exergy destruction. Dynamic simulation of the stack temperature is carried out in response to various control inputs and disturbances. Dynamic simulation exhibits the response rapidity of variables, strong couplings and different variation trends (monotone, overshoot or initial inverse response), due to the different time scales of electrochemical reaction, gas flow and heat transfer. This study lays a solid foundation for system optimization and dynamic control design.

Elaboration of Energy Flow Sankey Diagrams for the Central American Region to Improve National Energy Planning

This article addresses the development of energy flow diagrams for the Central American region, based on the World Energy Balance for the year 2019. The main objective of this work is to provide a diagnosis of the efficiency of the energy systems, as well as the components that integrate them, which help to identify the improvement areas for the reduction of energy consumption. The development of the energy flow diagrams follows a model stablished by the International Energy Agency, divided in: primary energy resources, conversion technologies, and sectors of demand. In addition to the model stated before, energy flow diagrams shown in this article contain energy services and energy losses, calculated through the efficiencies found for each sector of demand. Six energy flow diagrams were developed to represent the energetic outlook of the region in regards to energy efficiency, primary energy resource consumption, and final energy consumption by the sectors of demand, as well as the estimation of greenhouse gases (GHG) emissions. This work can serve as a guide for energy planning, by tracking the energy flows to reduce energy losses and CO2 emissions by improving the low efficiency areas.

Carbon Emission Peak Paths Under Different Scenarios Based on the LEAP Model—A Case Study of Suzhou, China

Environmental pollution caused by energy consumption is a global problem. Optimization of the energy system will contribute to the sustainable development of city, especially of the industrial cities. Based on the Long-term Energy Alternative Planning System (LEAP) model, the LEAP-Suzhou model was established to explore the energy system optimization and emission reduction path of Suzhou to 2050. By accounting for current energy consumption and carbon emissions, the baseline scenario (BAU) was established. According to the different methods and intensities of energy transformation, an industrial structure optimization scenario (ISO), an energy structure optimization scenario (ESO), and an energy transformation optimization scenario (ETD) were created. Combined with the energy flow diagram, the energy structure and the direction of optimization were analyzed. The results showed that the baseline scenario will consume 259.954 million tons of standard coal by 2050, and the carbon emission will be 677.6 Mt. Compared with BAU, the ISO, ESO, and ETD scenarios will reduce energy consumption by 37.9%, 37.4%, and 74.8%, respectively, by 2050. ETD had the best carbon dioxide reduction, followed by ESO, and finally ISO. Among them, the carbon emission of ETD will reach its peak around 2030 and decrease to 73.8 Mt in 2050, resulting in the best emission reduction effect. This scenario is the best path for Suzhou to achieve the goal of “carbon peak and neutrality” and sustainable development. The LEAP-Suzhou model successfully explores the low carbon path of Suzhou, provides policy guidance for the optimization of energy transition and carbon neutrality of industrial cities, In the future, the energy structure should be further optimized in Suzhou, and advanced energy technologies should be introduced to improve energy efficiency, especially for the power generation sector, and the proportion of clean energy such as gas should be further expanded.

Investigations on energy assessment, conservation potential, and recovery opportunities for stenter machines based on the field trial

ABSTRACT In this paper, energy assessment, conservation potential, and recovery opportunities are explored for a stenter machine as it is energy intensive and widely used in textile finishing plants. This work is based on factual data collected by rigorous and exhaustive field trials. Further, modified energy model equations are proposed to perform assessment and parametric analysis for the determination of the required energy, specific energy consumption, energy efficiency index, and energy conservation and recovery potential. It is important to note that the actual energy consumption is reduced to 730 kW (saving 10%) at optimal conditions. For efficient operation of the stenter machine, fabric speed, operating temperature, and recirculation ratio need to be kept as maximum as possible without altering fabric quality. Further, the energy flow diagram shows that exhaust out air contains considerable energy (884 kW), which can be recovered as (i) to preheat inlet air, reducing energy requirement by 7% and (ii) to heat water, recovering 170 kW (21% saving potential). Sensitivity index shows that operating temperature has a higher influence on the stenter machine performance; temperature below 130°C adversely affects it. Overall, 15–20% energy can be saved in the stenter by appropriately operating it at optimal condition.

Analysis and Improvement Measures of Driving Range Attenuation of Electric Vehicles in Winter

A great many EVs in cold areas suffer from range attenuation in winter, which causes driver anxiety concerning the driving range, representing a hot topic. Many researchers have analyzed the reasons for range attenuation but the coupling mechanism of the battery as well as the vehicle and driving conditions have not been clearly estimated. To quantitatively investigate the driving range attenuation of electric vehicles (EVs) during winter, an EV model mainly integrated with a passenger-cabin thermal model, battery model, and vehicle dynamic model was constructed and simulated based on the mass-produced Wuling HongGuang Mini EV. Real vehicle dynamic driving data was used to validate the model. Based on NEDC driving conditions, the driving range calculation formula and energy flow diagram analysis method were used. The reason for attenuation was evaluated quantitatively. Results show that battery energy loss and breaking recovery energy loss contribute nearly half of the range attenuation, which may be alleviated by battery preheating. Suggestions for extending driving range are proposed based on the research.

Power Distribution Strategy for an Electric Bus with a Hybrid Energy Storage System

To address the power distribution problem that occurs in hybrid energy storage systems (HESSs) in electric vehicles, a fuzzy control distribution method is proposed in this paper, taking the vehicle demand power; supercapacitor power, PSC;; and lithium battery power, Pbat, as the inputs and the power distribution factor of the supercapacitor as the output to control the power distribution of the composite energy storage system, in addition to dividing the whole working condition into three time scales, namely, long, medium and short. In this study, we conducted a comprehensive analysis and comparison with typical control methods regarding the energy storage element output power, battery state of charge (SOC) change, energy flow diagram and power frequency. The simulation experiment results show that the proposed strategy is more effective in reducing the peak output power of the power battery, improving the effective power utilization rate of HESS and the effective energy utilization rate. In order to further verify the effectiveness of the control strategy, a pure electric bus power system test bench was built based on similar principles, and a representative time period under the driving conditions of the China city bus (CHTC-B) was selected, involving an acceleration process from 30 to 48 s (process 1), a uniform speed process from 636 to 671 s (process 2) and a regenerative braking process from 1290 to 1304 s (process 3), further verifying the effectiveness and feasibility of the proposed control strategy.

Analysis and Modeling the Energy System of a Chemical Tanker by LEAP

Maritime transportation has been a cost-effective option among other transport modes. Meanwhile, this demand has been increasing day by day because of the expanding global economy. The ships are one of the most important transport and trade vehicles in the world; 90% of the world trade is carried out by maritime transport, and this sector plays a crucial role in climate change and global warming because it is one of the key sectors leading to emissions of carbon dioxide, the main greenhouse gas (GHG). In other sectors that lead to CO2 emissions, i.e., energy production, manufacturing industry, and heating in residences, energy efficiency has been improved and emissions have been reduced significantly. However, there has been no net reduction in the transport sector; total CO2 emissions have also increased because of the continuous increase in freight and passenger traffic, although efficiency has increased. Increasing the energy efficiency of a ship allows for fuel consumption reduction and GHG emissions. In this study, the energy system of a chemical tanker ship was analyzed and then modeled by using the long-range energy alternatives planning system, a widely used platform for energy policy analysis and climate change mitigation assessment, including a comprehensive energy flow diagram, namely, reference energy system. A base scenario was developed, and the ship’s energy system was convenient to be analyzed and evaluated in terms of technical, economic, and environmental aspects, including low-emission development strategies, to comply with marine engine regulations of the International Maritime Organization.

Design, simulation and analysis of monofacial solar pv panel based energy system for university residence: a case study

This paper proposes a design and software simulation of monofacial solar photovoltaic panel based energy harvesting system for university residence. As the site of the proposed system, the rooftop of North Hall of Residence of the Islamic University of Technology (IUT) is considered. The 3D model of the system is demonstrated by utilizing PVSOL software. The monthly energy production is obtained by performing the simulation in three software named PVSOL, PVsyst, and System Advisor Model (SAM). However, the monthly consumption of the residence is tabulated and graphical presentation is depicted. Hence, the energy flow diagram is illustrated showing that the proposed PV system can contribute 18.4% in the annual demand of the site. The performance of each of the software is evaluated and deviation analysis is performed so that more insight can be achieved in terms of harvesting solar energy. Hence, a cost-effective and self-reliant solar energy model for the rooftop of a university residence is proposed by utilizing monofacial solar PV panels.

Impacto ambiental de diferentes sistemas de produção agrícola

The efficient use of natural resources in production systems is essential for achieving ecological balance and sustainability in these systems. Current agricultural production systems have intensified the use of fertilisers and pesticides that contribute to an increase in energy flow, accelerating the process of degradation. The aim of this study was to evaluate, using emergy analysis, the environmental performance of different irrigated production systems for different sources of water, energy and fertiliser, and of rainfed systems under different types of soil preparation. The irrigated systems were studied in the experimental area of the Sewage Treatment Station (ETE) in Tianguá, Ceará (CE), and the rainfed models at the Fazenda Normal Farm in Quixeramobim, CE. Emergy analysis basically consists of three stages: construction of the systemic energy flow diagram, elaboration of the emergy evaluation table, and calculation of the emergy indicators. A mean value of 0.04 was found under the rainfed production systems, which shows less environmental stress compared to the irrigated systems, 0.30. The influx of economic resources into agricultural systems increases the environmental load and reduces renewability. Treated domestic effluent and photovoltaic solar energy afforded an increase in emergy yield and in the environmental sustainability of the production models.

A thermodynamic performance analysis of the agricultural sector of India

Thermodynamic analysis of Indian agricultural sector for a period of 14 years between 2001-2002 and 2014-2015 has been carried out in order to find the thermal efficiency and irreversible losses with the application of the principles of energy and exergy analysis. The devices such as tractors, power tillers using diesel and irrigation pump-sets using electricity, which consumes major portion of the energy inputs are assumed to be the representative of Indian agricultural sector. It is found that during the study period the overall exergy efficiencies (66.05% to 68.46%) are slightly less than corresponding energy efficiencies (66.09% to 68.47%). The energy and exergy flow diagrams and further improvement potential of this important sector are also presented. The results of this study can be used as guidelines for research and development such as analysing sectoral energy and exergy utilisation, providing measures for energy conservation and policy development.

Photonic hooks from Janus microcylinders.

Recently, a type of curved light beams, photonic hooks (PHs), was theoretically predicted and experimentally observed. The production of photonic hook (PH) is due to the breaking of structural symmetry of a plane-wave illuminated microparticle. Herein, we presented and implemented a new approach of utilizing the symmetry-broken of the microparticles in material composition for the generation of PHs from Janus microcylinders. Finite element method-based numerical simulation and energy flow-represented theoretical analysis were used to investigate the field distribution characteristics and formation mechanism of the PHs. The full width at half-maximum (FWHM) of the PH (∼0.29λ) is smaller than the FWHM of the photonic nanojet (∼0.35λ) formed from a circular microcylinder with the same geometric radius. By changing the refractive index contrasts between upper and lower half-cylinders or rotating the Janus microcylinder relative to the central axis, the shape profiles of the PHs can be efficiently modulated. The tunability of the PHs through simple stretching or compression operations for the Janus microcylinder constituted by one solid inorganic half-cylinder and the other flexible polymer half-cylinder was studied and discussed as well.

Utilization of Mechanical Energy During Push-Off in Human Walking

Notable disagreements have emerged from research on the role of ankle during push-off, the resolution of which is crucial to the understanding of the human movement science or the clinical treatment in rehabilitation. This research proposed a new symbolic convention of energy flow diagram to manifest where the ankle power generated during push-off is transmitted to in order to ease of interpreting the function of the ankle. Gait data of eight healthy young adults at self-selected speeds were analyzed. Energetic data of the pelvis and lower limb were used to construct an energy flow diagram at the instant of peak ankle power generation during push-off. Our results suggest that the ankle mainly contributes to increase the kinetic energy of the ipsilateral leg in preparation for swing during push-off. The magnitude of the power flowing to the pelvis, which could be used for forward propulsion, was only 10% of that generated by the ankle. The energy flow diagram with the proposed convention is a useful analytic tool with applications across many disciplines, for example, evaluating the energy performance of elite athletes, designing the powered prostheses, and revealing the compensatory movement strategy of people with disabilities.

Thermodynamic analysis of a combined cooling, heating and power system based on solar thermal biomass gasification☆

The objectives of this paper are to propose a novel combined cooling heating and power (CCHP) system based on solar thermal biomass gasification, and to present thermodynamic analyses to effectively improve the utilization of distributed renewable energy sources. By adopting the Engineering Equation Solver software, the thermodynamic models of components were constructed, and the simulation procedures, mainly including the heat transfer of the solar cavity receiver and the biomass gasification, were presented. Based on a 100 kW electricity capacity, the design parameters of the CCHP system were obtained to simulate and discuss the thermodynamic performances and the energy and exergy flow diagrams in the cooling and heating operation modes. The influences of the key variable parameters, including the electric load ratio and the solar direct normal irradiance in the off-design work conditions on the thermodynamic performances, were analyzed and discussed. The simulation results indicate that the CCHP system achieves average energy and exergy efficiencies of 56% and 28%, respectively, and the energy ratio of solar to biomass is approximately 0.19 in the full load operating mode. Compared to the conventional biomass gasification CCHP system without solar energy, the increasing ratio of heating value of product gas based on the solar thermal biomass gasification reaches 55.09%, and the biomass saving ratios are approximately 9.22% and 2.02% in the cooling and heating modes respectively, which indicate that the proposed hybrid system is an effective and feasible method to improve the utilization efficiency of biomass energy.

First- and second-law thermodynamic analyses of a combined natural gas cyclepower plant: Sankey and Grossman diagrams

The natural gas combined cycle power plant is one of the best options for generating electricity due to its use of low carbon fuels, high efficiency, and operational flexibility. These plants consist of a combination of Brayton and Rankine cycles, and investigation of these cycles is performed in this paper. Here the parameters of pressure and temperature used in the calculations are taken from a combined cycle power plant. The net power output of the system at 25 °C ambient temperature and 101.325 kPa pressure was calculated as 45 and 12 MW for Brayton and Rankine cycles, respectively. In addition, Brayton, Rankine, and combined cycle efficiencies were calculated as 37.5%, 27%, and 47.5%, while the exergy efficiencies were determined as 36%, 44%, and 46%, respectively. In the system elements, the most energy was lost in the combustion chamber and the highest exergy efficiency was achieved in the compressor at 95% level. Impacts of an increase in ambient temperature, compressor pressure ratio, and change on turbine inlet temperature were further investigated. Energy (Sankey) and exergy (Grossman) flow diagrams were further drawn based on the analyses obtained from the combined cycle power plants.

Implementation of green manufacturing concepts: a case study of tea manufacturing industry in Sri Lanka

The objective of this study is to identify the potential implementation of green manufacturing concepts on medium scale tea industries in Sri Lanka. Five medium scale tea factories located in southern province were selected as the sample and case study approach was followed. The data were collected through regular factory observations and secondary sources including published reports and documents of the companies. Material and energy flow diagram was used as the main tool for the analysis. The result reveals that there are significant environmental issues such as large-scale raw material wastage, and high level of energy, water consumption and harmful emissions. This study suggests that energy consumption can be reduced by introducing new equipment, methods and systems such as installing variable speed motors, power factor correction capacitors, variable frequency drivers, replacing light emitting diodes (LEDs) with compact fluorescents, implementing well-planned production schedules, and fixing net metering system and solar panels.