Improve Energy Utilization Efficiency Research Articles

Optimal Configuration of Power/Thermal Energy Storage for a Park-Integrated Energy System Considering Flexible Load

The park-integrated energy system can achieve the optimal allocation, dispatch, and management of energy by integrating various energy resources and intelligent control and monitoring. Flexible load participation in scheduling can reduce peak and valley load, optimize load curves, further improve energy utilization efficiency, and reduce system costs. Based on this, firstly, a flexible power-load model is established considering the translatable load, transferable load, and reducible load; and a thermal flexible load model is established based on the fuzziness of user perception of temperature in this study; then, the mixed integer linear programming method is adopted, and the sum of the carbon transaction cost, operation and maintenance cost, compensation cost, power purchase cost, gas purchase cost, wind and light abandonment penalty cost and investment cost of the system is minimized as the objective function, and the configuration of the integrated energy system is optimized, and the optimal capacity of each equipment and the output of each period are obtained. Finally, taking an industrial park in Liaoning Province of China as an example, the analysis is carried out. The example results show that by scheduling the flexible electrical load and flexibly adjusting the indoor temperature, renewable energy consumption can be promoted, and electricity load and heat-load curves can be optimized to increase the installed capacity of wind turbines, reduce the capacity of gas turbines, batteries, and heat-storage tanks, improve system economy, and improve the penetration rate of renewable energy.

Study on optimal energy dispatch of electricity-heat-cool-gas agricultural industrial Park with renewable energy

Since the release of China’s rural revitalization strategy, rural areas have experienced rapid development, but at the same time, the imbalance between rural energy demand and infrastructure has become more prominent. In this regard, this paper considers the use of abundant renewable energy in rural areas to participate in energy generation and build an integrated energy system for agricultural parks containing electricity, heat, cold and gas loads. Based on this idea, it is necessary to establish mathematical models for various equipment in agricultural parks. Then, the maximum output and daily load curves of the agricultural park were predicted, and the TOU price was added at the same time. Finally, the objective function is to minimize the cost of energy use, and the integrated energy system of the electricity-heat-cooling-gas agricultural park using renewable energy was optimized a few days ago. In addition, through simulation examples, it has been proven that this method can increase the utilization of renewable energy, improve energy utilization efficiency, and have dual economic and environmental benefits.

Prospective Analysis of Aluminum Metal for Energy Applications

With the increasing global demand for sustainable energy, metal aluminum has shown tremendous potential and advantages as an important energy material. This article focuses on exploring the application prospects of metal aluminum in renewable energy, energy storage, and energy efficiency. In the field of renewable energy, metal aluminum can be used in the manufacturing of solar cell components and auxiliary equipment. Its properties make it a suitable material for these applications. In terms of energy storage, metal aluminum exhibits high performance and a long lifespan in hydrogen storage and energy storage devices. It shows promise as an efficient and durable choice for these applications. In the field of energy efficiency, metal aluminum plays a significant role as a lightweight material in the automotive industry and in thermal management technologies. It can contribute to improving energy utilization efficiency and reducing energy consumption in various applications. However, the application of metal aluminum still faces some challenges, including cost and sustainability issues. Therefore, further research, development, and collaboration are needed to promote the application and development of metal aluminum in the energy sector, contributing to the achievement of sustainable energy goals.

Calculating carbon emissions and selecting carbon peak scheme for infrastructure construction in Liaoning Province, China

Carbon emissions from infrastructure development in Liaoning Province are growing more significant. However, there is a lack of comprehensive research on predicting and analyzing carbon emission peaks in this context. Addressing this research gap is crucial for understanding emission trends and crafting effective reduction policies. This study employed a method that combines carbon emission factors with emergy, selecting six factors including urbanization rate, energy intensity, road infrastructure development, per capita emergy, energy density, and transportation structure. By combining the carbon-intensive and carbon-mitigating factors, the study estimated the carbon emissions from infrastructure construction in Liaoning Province. Using the STIRPAT model, the study predicted the future peak of carbon emissions from infrastructure construction in Liaoning Province. Four development scenarios were considered, namely, the inertia scenario, the mitigation scenario, the energy-saving scenario, and the low-carbon scenario, taking into account different combinations of economic and social development variables. In the low-carbon scenario, Scheme 13 was considered the optimal path for Liaoning Province to reach the peak of carbon emissions from infrastructure construction. This scheme adopts measures to maintain stable economic development, improve energy utilization efficiency, and optimize transportation structures. However, this study has certain limitations. Potential uncertainties in data completeness and quality may affect the findings. Additionally, the applicability of the results could be restricted since this study solely focuses on carbon emissions from infrastructure construction in Liaoning Province, limiting its generalizability due to geographic constraints.

Co3O4 nanosheets modified by Ni@C nanoparticles as effective flow-through electrode for electro-activation of PMS: Ni@C as electron shuttle for accelerated Co3+/Co2+ cycle in bulk Co3O4

Electro-assisted activation of peroxymonosulfate (EA-PMS) by transition metals oxides (TMOs) has been extensively studied for the removal of organic pollutants. Despite TMOs possess considerable activity and affinity to PMS, their poor bulk conductivity still limits the electron exchange during the TMδ/δ+1 redox cycle, especially the efficient reduction of TMδ+1 via cathodic process. In this study, carbon felt loaded with modified Co3O4 nanosheets (Co@FCF) was fabricated and applied as the flow-through electrode of EA-PMS process, where the Co3O4 nanosheets were embedded with numerous metallic Ni particles encapsulated within carbon layers (Ni@C). Driven by weak electric current, continuous electrons can be supplied to the bulk Co3O4 from the electron-rich Ni@C nanoparticles, resulting in accelerated Co3+/Co2+ cycle, enhanced production of SO4·− and improved energy utilization efficiency. Electrochemical tests along with density functional theory calculations indicate that the unique structure of Co@FCF played essential role in the enhanced performance.

The effect of electricity market reform on energy efficiency in China

Since 2015, China has embarked on a new round of reforms to further promote marketization of the power sector. The present study evaluates this reform by exploring its impact on energy efficiency in China using a novel integrated approach. First, to distinguish the heterogeneous impacts of the reform on energy production and consumption sectors, this study identifies energy efficiency into production efficiency and utilization efficiency based on the super-efficiency network slacks-based measure–data envelopment analysis (SBM–DEA) with an undesirable output. Thereafter, we identify the impact of the reform on energy production and utilization efficiencies by applying a multi-period difference-in-differences (DID) method. We find that the energy efficiency of most provinces of China is relatively low, and energy production efficiency is generally lower than energy utilization efficiency. Although energy efficiencies of most provinces show an upward trend after 2015, the efficiency gap across provinces has increased over time. Moreover, the market reform has no significant impact on energy production efficiency. However, the reform significantly improves energy utilization efficiency, and this effect is sustainable after the reform. The study findings extend our understanding of the effects of the reform and suggests that this reform introduces heterogeneity in the energy sector. This study also holds significant policy implications for furthering the power system reform and narrowing the energy efficiency gap across regions in China.

Current Situation and Development Trend of Urban Centralized Heating

In the context of sustainable development, countries around the world are increasingly paying attention to environmental issues. In this context, the high energy consumption and high pollution of urban heating systems have become urgent issues that need to be addressed. Promoting urban centralized heating is an inevitable choice to effectively solve these problems. The heating system is an important component of urban development, and central heating plays a crucial role in energy utilization. In order to meet the requirements of sustainable development, it is necessary to actively improve the central heating system and solve the problems of low resource utilization and high energy consumption in traditional decentralized heating methods. This can reduce air pollution and improve the overall quality of the urban environment. A comprehensive analysis of the relevant content of urban central heating systems, including understanding the existing problems and development trends, helps to formulate reasonable measures to promote the development of central heating. Promoting the development of central heating systems is an important component of urban sustainable development. By improving energy utilization efficiency, reducing dependence on traditional fossil fuels and using advanced technologies, central heating systems help to achieve the Sustainable Development Goals and improve the quality of life of urban residents. A comprehensive analysis of the current situation and development trends of urban central heating can help formulate reasonable measures to promote the development of central heating, achieve a more sustainable future, and create a sustainable urban environment.

Central inspections of environmental protection and transition for low-carbon Chinese cities: Policy intervention and mechanism analysis

The central government continues to elevate ecological considerations in local governments' incentive and penalty systems under the relentless pressure of dual carbon objectives. The central inspections of environmental protection (CIEP) program have emerged as an increasingly significant tool and institutional arrangement for environmental governance. Therefore, this study evaluates the impact of CIEP policy intervention on carbon emissions intensity employing the time-varying difference-in-differences model (TV-DID) in 233 Chinese cities from 2008 to 2019. The empirical evidence reveals that CIEP's enforcement significantly reduces carbon emissions intensity, and these effects are consistent for different model specifications. The mechanism analysis indicates that CIEP decreases carbon emissions intensity by improving energy utilization efficiency and intensifying local government environmental attention. The negative influence of CIEP on carbon emission intensity is only significant in eastern cities, high administrative hierarchy cities, and non-resource-based cities but insignificant in mid-western cities, ordinary cities, and resource-based cities. These findings support the CIEP implementation to achieve energy transition and carbon neutrality targets.

Multi-objective Collaborative Planning Method for Micro-energy Systems Considering Thermoelectric Coupling Clusters

As the continuous development of integrated energy system and distributed power supply, operation economy and regional energy Internet reliability, especially micro-energy system, are increasing. Therefore, it is necessary to build multi-energy complementary micro-energy system, innovate energy supply mode, realize collaborative and efficient utilization among multi-energy systems, improve energy utilization efficiency and absorb renewable energy. In this paper, the decision model of distribution network planning scheme including distributed generator supply is established from four aspects: investment and operation cost, extra reserve capacity, energy conservation, reliability cost. The decision model involves a lot of parameter calculation and selection judgment, so after the decision goal is determined, an decision framework based on DS-MAS is established, that is, parameters are automatically calculated and selected based on different scenarios. Model validity is proved via a practical decision project.

Enhancing the sensitization of Ce3+ on Sm3+ by tri-doping Gd3+ in hexagonal NaYF4

Sm3+ is one of the most fascinating activators because of its dominate emissions in visible region with abundant potential applications. However, its absorbing cross section and ability to be sensitized are ineffective and unpractical due to the low quenching concentration. In this work, a series of β-NaYF4: Ce3+/Gd3+/Sm3+ were synthesized. Pure hexagonal phase of all samples was guaranteed by powder XRD patterns and SEM images, despite the morphology was influenced by rare earth components. The luminescence properties of β-NaYF4: Ce3+/Gd3+/Sm3+ were systemically investigated by the photoluminescence excitation spectra, emission spectra and life time decay curves. Tri-doping Gd3+ into β-NaYF4 was found to be very helpful to enhance the sensitization of Ce3+ on Sm3+. Furthermore, the rate equation of sensitizers was induced to analyze details of competition between ET Ce → Gd and Ce → Sm. Rate equation analysis also indicated that the enhancing effect of Gd3+ on sensitization is mainly due to the greatly improved energy utilization efficiency.

IoT adaptive threshold energy management algorithm based on energy harvesting

The Internet of Things (IoT) provides a promising solution to resolve pipeline conditions and oil and gas leakage detection problems. How to realize complex data monitoring and data uploading in energy-constrained sensor nodes is an urgent problem for oil and gas IoT. Energy harvesting technology and energy-efficient management have been introduced to the oil and gas IoT to improve energy utilization efficiency and good network performance. In this paper, we propose an energy management algorithm for oil and gas IoT. The scheme consists of: (1) the nodes mode switching strategy which allows sensor nodes to perform specific tasks based on the current energy level and (2) cluster head selection algorithm which considers energy harvesting and energy consumption ratios to achieve a balance between network performance and lifetime. Moreover, for the timely upload of essential data, we propose an adaptive threshold strategy that considers the energy level and importance level of sensor nodes to prioritize the transmission of important data under energy-limited conditions. The simulation results show that the proposed scheme can simultaneously prolong the network lifetime and improve energy utilization efficiency and is superior to existing schemes.

Comparative investigation on techno-economics of cascade supercritical CO2 combined cycles for waste heat recovery of typical gas turbines

An advanced supercritical CO2 (sCO2) power cycle for recovering waste heat from the gas turbine (GT) is thought to be an effective way to improve energy utilization efficiency and achieve low-carbon power generation. To obtain the best techno-economic sCO2 cycle configurations at various capacity levels, eight cascade cycle configurations were designed for coupled power generation with typical gas turbines in the power range of 11.4–593 MW, with the number of heaters, the number of split flow branches, and inter-cooling process as variables. The techno-economics of cascade sCO2 combined cycles were assessed and compared using various engineering equations. The results show that adding a heater and inter-cooling process increases the levelized cost of electricity (LCOE) by about 0.53 $/(MWh) and 0.99 $/(MWh) on average, respectively, while adding a split flow branch can decrease the LCOE by about 1.3 $/(MWh) on average. In addition, the increase in installed capacity can lead to a lower LCOE. When the net power range of the combined cycle is 14.9–767.1 MW, the LCOE of the triple cascade cycle ranges from 56.45 to 32.52 $/(MWh). Compared to a conventional combined cycle, using a cascade sCO2 cycle as the bottom cycle can decrease the LCOE by approximately 12.1–16.2%. Sensitivity analysis reveals that natural gas price has the greatest effect on LCOE, followed by annual operating hours, and suggests efficient ways to decrease the LCOE. The triple cascade cycle is recommended at all capacity levels due to its lower LCOE. The specific cost (SC) and LCOE prediction equations for the combined cycle are proposed for the first time to aid in the design and techno-economic assessment of the cascade sCO2 combined cycles.

Research on performance of radiant floor heating system based on heat storage

With the development of the economy, improving energy efficiency and saving energy have become important issues that need to be addressed. In terms of building energy efficiency, combining phase change heat storage material with floor radiation heating is an effective way to improve energy utilization efficiency. In this paper, a composite phase change heat storage material used in radiant floor heating was introduced. Based on the selected materials, experiments on floor radiation heating system based on heat storage in different environments during the heating season were conducted. The results showed that thermal conductivity of composite phase change heat storage material increased by a maximum of 97.2%, and the maximum heat release time can be obtained 6 h. By using this radiant floor heating system, a balance between heating comfort and economy has been achieved, so this system will have a good applied foreground.

Experimental and modeling study on energy flow of 250 kW alkaline water electrolysis system under steady state conditions and cold start process

Improving the energy utilization efficiency of alkaline water electrolysis system (AWE) is one of the urgent problems at this stage. This study explores the heat flow and energy distribution under steady state and cold start processes by establishing a multi-physical field coupled AWE system model including heat transfer, mass transfer and electrochemistry, based on this, the methods to improve energy utilization efficiency are proposed. The system power consumption at full load is 272.7 kW, the electrolyzer accounts for up to 88.4%, of which, the useless heat production and parasitic current are the main factors that cause the electrolyzer energy loss, accounting for 21.2% and 3.1% of the total power consumption, respectively. The electrolyzer useless heat production also significantly contributes to the chiller energy consumption, which accounts for 5% of the system power consumption. Improving the electrolyzer performance and minimizing its heat production is essential to optimize the system efficiency. During the AWE cold start process, the constant voltage control has a shorter cold start time than the constant current control, but their power consumption differences in terms of heat and hydrogen production are small. Reducing the system thermal capacity is extremely effective in speeding up the cold start process compared to optimizing the power load type, which can cut the cold start time to less than 1 h.

Model-data-event based community integrated energy system low-carbon economic scheduling

With environmental pollution becoming an increasingly serious problem, it is crucial to develop renewable energy and improve energy utilization efficiency. Integrated energy system realizes complementary utilization of various energies by integrating various heterogeneous energies. However, the uncertainty of generation and load causes random fluctuation, making it difficult to accurately and quickly adapt to the dynamic environment. Therefore, this research designs a model-data-event based low-carbon economic scheduling framework for the community integrated energy system. Firstly, the low-carbon economic scheduling problem is mathematically described, then the decision-making problem is expressed as a reinforcement learning framework. An improved DDPG algorithm which can cope with the uncertainty is used to make real-time scheduling decisions. Considering the instability of reinforcement learning algorithm, this research proposes a heuristic real-time power allocation strategy, which comprehensively considers the degree of imbalance and the schedulable ability of the responders. The event-driven mechanism enables the responders to respond quickly and accurately to the energy compensation requirements. Simulation results indicate that the proposed scheduling framework can adapt to different parameters and reduce energy costs up to 6.65% and 3.85% compared to the deep Q network and soft actor critic algorithms, with the computational efficiency 11 times higher than that of model predictive control algorithm.

Membrane humidity control of proton exchange membrane fuel cell system using fractional-order PID strategy

Dynamic humidity control is a crucial factor affecting the working performance of proton exchange membrane fuel cell (PEMFC) system. Proper membrane humidity can guarantee power generation performance, improve energy utilization efficiency, prevent irreversible degradation of the proton exchange membrane (PEM). In this paper, a dynamic control model for PEMFC humidity management is proposed, and a fractional-order PID (PIλDμ) control strategy is introduced to balance the membrane humidity of PEMFC. The results show that comparing with traditional PID control methods, the PIλDμ control shows shorter response time, lower overshoot in membrane humidity control, and higher power generation efficiency in PEMFC system. In addition, the performance of the PEMFC using PIλDμ control method at different pressure and temperature conditions is discussed. The power generation efficiency of the PEMFC under PIλDμ control is improved, which is 2.1 %, 3.9 % higher than that of fuzzy PID and conventional PID control method.

Temporal and Spatial Divergence of Embodied Carbon Emissions Transfer and the Drivers—Evidence from China’s Domestic Trade

To understand the embodied carbon transfer in China’s domestic trade from 2007 to 2017 and its driving forces, we quantitatively measured the embodied carbon transfer among 30 provinces by using the Multi-regional input-output (MRIO) model, explored the temporal and spatial evolutionary features of the interprovincial embodied carbon emission transfer by using spatial autocorrelation, and further revealed its drivers using the Geographical Detector Model for the first time. We find that: (1) Based on the producer and consumer accounting principles, the amount of embodied carbon emissions of each province has increased, and there are huge differences. (2) The number of provinces with net embodied carbon emissions transfer is increasing, to 18 in 2017 and the target provinces are mostly energy-rich regions, such as Shanxi, Xinjiang, and Inner Mongolia, which have a severe “carbon leakage” phenomenon with developed coastal provinces. (3) The scale and spatial distribution of net carbon transfer out shows a characteristic of “high in the north and low in the south”, and the tendency of net transfer from the less developed provinces to the developed regions is becoming more and more obvious. (4) The global differences in the promoting factors of the net embodied carbon transfer are not prominent, but the differences at the local scale are significant, with energy intensity and environmental regulation playing an increasingly significant role. Therefore, it is recommended to strengthen low-carbon technology innovation and environmental regulation, increase the percentage of renewable energy consumption, accelerate the mobility of various resource factors, and improve energy utilization efficiency.

Preliminary design and techno-economic assessment of a trigeneration system integrated with compressed air and chemical energy storage

The advantages of compressed air energy storage (CAES) have been demonstrated by the trigeneration system with the characteristic of high penetration of renewable energy. However, since the irreversible loss of compression heat occurs during the overall operation processes of CAES, the development of CAES with high energy efficiency has been hindered by the conventional conversion pathway of compression heat. Therefore, a trigeneration system integrated with compressed air and chemical energy storage is proposed in this study to improve energy utilization efficiency. The compression heat is converted into H2 and CO via the endothermic methanol decomposition reaction to improve its energy level during the charging process, and then the syngas production can be used for air preheating during the discharging process. The parametric analysis is first performed to investigate the technical and economic feasibility of the system. Subsequently, the multi-objective optimization is conducted to identify the tradeoffs in the thermo-economic performance of the system and acquire the optimal values of operating parameters. Notably, the proposed system with a computed exergy efficiency of 43.31% and levelized cost of energy (LCOE) of 97.53 $/MWh is selected as the most compromise solution by the decision maker of Technique for Order Preference by Similarity to an Ideal Solution among the Pareto optimum fronts, which are 8.47% higher than the exergy efficiency and 7.39 $/MWh lower than the LCOE under the design conditions.

Evolving Strategies Toward Seebeck Coefficient Enhancement

ConspectusThermoelectric (TE) materials, interconverting electrical energy with heat energy, could improve energy utilization efficiency, optimize the energy structure, and promote sustainable economic and social development. The Seebeck coefficient (S), characterizing the output power, is a particularly important parameter for conversion efficiency of TE materials. In the past 200 years since the Seebeck effect was discovered, researchers have tried various ways to increase S to increase the TE performance of materials. In addition to traditional TE approaches to enhance the S, such as energy filtering effect and band convergence, innovative methods of improving the generalized S have emerged in interdisciplinary disciplines, like spin entropy.We have successfully optimized the S to boost the performance of many TE materials, such as SnTe, SnSe, and SnS. In this Account, we focus on the physical mechanisms affecting the S, discuss traditional and innovative methods to optimize the S, and look forward to some promising interdisciplinary approaches for further research to improve the S. First, we analyze the physical mechanism of the basic parameters and their effects on S. Optimizing the carrier concentration, the adjustment of scattering behavior and the increment of effective mass are common methods of improving the S. Second, we summarize several emerging interdisciplinary methods that could enhance the generalized S, like the spin caloritronic effect including magnon/paramagnon drag, spin entropy, and spin fluctuation. The spin Seebeck effect liberates the traditional direction limit between temperature and S and gives a new path toward the S enhancement. We also emphasize the significance of the utilization of phonon drag in the low temperature area. Third, based on previous work, we think the topological states regulation is a burgeoning innovative method for S enhancement of TE materials. Last, we discuss and envision some interdisciplinary strategies for further improving S in the future. This Account indicates that S could be regulated as required, and the interdisciplinary research is beneficial to expand the methods of optimizing TE parameters. We hope to draw the attention of researchers to the enhancement of S and TE performance via innovative study and guide researchers to promote the theoretical innovation research of TE materials.

Photovoltaic-based energy system coupled with energy storage for all-day stable PEM electrolytic hydrogen production

Photovoltaic (PV) power generation coupled with proton exchange membrane (PEM) water electrolysis favors improving the solar energy utilization and producing green hydrogen. But few systems proposed focus on achieving all-day stable hydrogen production, which is important for the future large-scale hydrogen utilization. Herein, a PV-Battery-PEM water electrolysis system for hydrogen production was constructed. An energy management strategy (EMS) was proposed to achieve the goal of all-day stable hydrogen production, improve energy utilization efficiency and reduce light discard rate. The PV power generation system, battery system and PEM electrolyzer for hydrogen production system were first established by Matlab/Simulink platform. Then, the overall PV-Battery-PEM electrolyzer system for hydrogen production was constructed, and the effectiveness of EMS was verified. The energy efficiency of the system under different working conditions with and without battery for energy storage was analyzed. The results show that the proposed energy management strategy can meet the purpose of all-day stable hydrogen production. Under the same working conditions, the energy efficiency of the system with battery for energy storage increases by 2–4% compared with the system without battery for energy storage, which indicates that the addition of energy storage can improve the energy utilization and reduce the light discarding.