Comprehensive Utilization Efficiency Research Articles

Thoughts on Teaching Reform of Resources Majors in Colleges and Universities under the Background of Carbon Peak and Carbon Neutralization—Taking Mineral Resources Exploration Course as an Example

On 22 September 2020, General Secretary Xi made a solemn commitment to the international community at the general debate of the seventy-fifth session of the United Nations General Assembly to achieve carbon peak and carbon neutrality, and he announced specific goals at the Climate Ambition Summit. China is striving to achieve carbon peak by 2030 and carbon neutrality by 2060. At the same time, during the Fifth Plenary Session of the Nineteenth Central Committee of the CPC and the Central Economic Work Conference, specific arrangements for related goals have been made. During these two sessions in 2021, carbon peak and carbon neutralization were also mentioned in the government work report for the first time, which became the “hot words” discussed by the delegates and one of the key subjects of the 14th Five-Year Plan. Against the current backdrop of “double carbon”, reforms must urgently be made in the education and teaching of the resource major in colleges and universities to achieve the goal of carbon neutralization with high quality, promote discipline construction, and explore and implement the development model of “new engineering”. With regard to the resource exploration industry, mining, dressing and smelting will produce a large amount of carbon dioxide, solid waste and tailings, which can be neutralized by injecting solid waste or tailings reservoirs through green mine construction and carbon capture. On the one hand, the comprehensive utilization efficiency of mines can be improved in this way. On the other hand, a large amount of carbon can be stored underground, which is an important method of achieving the goal of carbon neutrality. In this study, we took the core course “Mineral Resources Exploration” from the resource exploration major as an example to think about and study the ways the education and teaching of resource majors could be reformed, such as exploration engineering under the guidance of the carbon neutrality target, which has certain guiding significance regarding the improvement of the training quality of resource major students.

An approach to optimize building area ratios scheme of urban complex in different climatic conditions based on comprehensive energy performance evaluation

In the context of the global energy shortage, urban complexes have attracted more and more attention from energy-saving research due to their large number and great energy-saving potential. While, the energy performance factors are rarely considered in the function scheme decision of urban complex in the recent pre-programming process. Optimizing the building area ratio scheme of urban complex is the key link to improve the comprehensive energy utilization efficiency. This paper proposes an approach to optimize building area ratio scheme of urban complex from energy performance perspective by energy simulation, scenario analysis and demand side management methods, and provides a data set of rankings of urban complex function combination schemes by evaluating the performance of energy load leveling and the degree of load stability of each building area ratio scheme in different climatic conditions, respectively. The results indicate that: 1) the different building area ratios notably affect the integrated operating energy performance of urban complexes with a maximum evaluation indexes difference of more than 85%; 2) the evaluating and optimizing results of the building area ratio schemes show broadly similarity in different climate conditions; 3) the optimal building area ratio scheme of urban complex is usually with less “shopping mall” (0 ∼ 10%), more “residence” (more than 35%), and floating ratio of “office” and “hotel” (0 ∼ 35%). The main findings of this study provide a quantitative basis for the architectural pre-programming and function scheme decision-making of urban complex by demand-side energy management to improve the energy efficiency, so as to guarantee the energy supply security.

Experimental and Numerical Study on the Performance of Innovative Bifacial Photovoltaic Wall System

• A BI-PVW system was innovatively developed, which could enhance the power generation. • The maximum comprehensive utilization efficiency of solar energy could reach 40%. • Ventilation of the BI-BVW system could bring 21.2% energy saving effect to the building. The combination of PV and building envelope can provide clean energy for building and greatly reduce the occupancy area of PV. The challenges include how to increase the power generation and reduce the building energy consumption by using the PV system. In this study, bifacial PV module was innovatively combined with building exterior wall to form bifacial PV wall (BI-PVW) system, which could use the high reflectivity of wall to enhance the power generation of the back side and decrease the building heat load through indoor ventilation. To develop particular parameters of the best performance of the system, a preliminary design was carried out. And based on the design, an experimental platform was set up to analyze the energy utilization under different ventilation strategies. The comprehensive utilization efficiency of solar energy could reach 40% in sunny days. Then the simulation model validated by experiments was used to further analyze the performance of building with BI-PVW system. It could be found ventilation can bring 21.2% energy saving effect to the building. The results in this study could provide beneficial effect on the development of the application of bifacial PV in building.

Reuse of Cornus officinalis nutlet for bioenergy

As a traditional nourishing Chinese herbal medicine, Cornus officinalis Sieb. et Zucc. has a long history of application. At present, only the flesh of the fruit of Cornus officinalis is used as a medicine, which wastes a large quantity of ingredients in the nutlet. To improve the comprehensive utilization efficiency of the fruit’s nutlet, which could be used when there is a shortage of the plant’s fruit in the market, this study used Fourier transform-infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), thermogravimetric (TG) analysis, pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS), and nuclear magnetic resonance (NMR) techniques to analyze the Cornus officinalis nutlet. The results showed that the active ingredients of Cornus officinalis nutlet have great medicinal value and could become a substitute for the fruit. After extracting the active ingredients, the residue can be used as a good biomass liquid fuel, providing reference for the future to replace fossil fuels. This study provides the scientific basis for the comprehensive utilization of high-quality resources for Cornus officinalis.

Application of BIM Digital Information Technology in the Economic Optimization Operation of Integrated Energy Systems

Energy is an important support for national economic development, and energy security directly affects national security, sustainable development, and social stability. The Middle East has the largest energy reserves in the world. Saudi Arabia is located in the Middle East and is a big energy country with very rich resources. With the reduction of fossil fuels and the increasingly prominent problem of climate change, the sustainable supply of energy while reducing environmental pollution and economic costs in the process of energy use is a problem facing the world today. In order to fully absorb clean energy, improve energy efficiency, and reduce fuel costs and environmental costs, we studied the impact of BIM digital information technology on the economic optimization of integrated energy systems. The integrated energy system has the characteristics of multienergy input and multienergy output. In terms of energy output, the system uses the principle of energy cascade utilization to recover and utilize the waste heat generated by the traditional generator set and then collects it through absorption. Compared with the traditional single-stage utilization of energy, the integrated energy system uses various forms of power, for example, power, heating, cooling, and natural gas, to achieve economic optimization by improving the comprehensive energy utilization efficiency through multienergy complementation. Through the investigation and comparison of the optimal dispatching operation cost, energy use cost, pollutant treatment cost, and equipment maintenance cost of 3 enterprises, the results show that the comprehensive energy system using BIM digital information technology can reduce the energy use cost by 8.7%. Moreover, the cost of pollutant treatment and the cost of equipment maintenance have been reduced to a certain extent, which has a certain optimization effect on the economy of comprehensive energy of enterprises.

A Comprehensive Utilization Efficiency Evaluation of Iron Tailings based on the Differential — Benefit Evaluation

At present, in the evaluation of iron tailings resources, the single evaluation of a certain aspect is limited to the qualitative evaluation, and there is no uniform standard in either theory or method. In this paper, based on the grey group analytic hierarchy process and fuzzy mathematics as the analysis tool, the benefit of the iron tailings resources is analyzed, From resource benefit, economic benefit, environmental benefit and social benefit several aspects to build the differential - efficiency index system and established the differential-benefit evaluation model and the influence of iron tailings resource evaluation of the weight of each index distribution, is obtained by correlation analysis and the likelihood of benefit index influencing the size of the order, to a certain extent, verified the rationality of the index weight, provides a theoretical guidance for iron tailings resource utilization.

Risk Control in Optimization of Cascade Hydropower: Considering Water Abandonment Risk Probability

Water abandonment risk caused by inflow uncertainties is a major problem in cascade hydropower generation operation and water resources management. In this study, we propose a theoretical estimation method (TEM) to calculate water abandonment risk probability (WARP) utilizing sample inflow data and historical forecast errors. The method analyzes the differences in risk quantification between the head hydropower station and downstream stations, and the corresponding probability formula is provided. Then, a short-term optimal operation model of cascade hydropower stations considering the additional WARP water level constraints is constructed to dynamically control water level risk. The Dahuashui (DHS)-Geliqiao (GLQ) cascade hydropower stations in the Wujiang River Basin of China is investigated as a case study. The results show that compared with the historical scheme, the total amount of water abandonment of DHS, GLQ and DHS-GLQ in the WARP optimal scheme decreases by 11.69%, 47.69% and 28.27%, respectively, and the flood peak of GLQ is reduced by 21.6%. In conclusion, compared with the traditional control approach and actual operation processes, the proposed risk control in optimization of cascade hydropower considering WARP can improve the comprehensive utilization efficiency of cascade hydropower systems by reducing the occurrence of water abandonment and thereby increase generation profits.

Research progress of wind energy utilization in building environment

Against the backdrop of the increasing global clean energy crisis, the development and efficient use of clean and renewable energy has become an important theme in today's society. In the use environment of various urban public buildings, the main difference of wind energy is that it can not only be directly applied to the urban buildings itself, but also does not need any transportation tools. According to the development status of building wind energy environment research in china and abroad, the main characteristics of building wind energy environment using wind energy in china are analyzed. the feasibility of using main wind energy in building wind energy environment in china is discussed. the main utilization methods of building wind energy environment using wind energy including natural ventilation system exhaust and building wind energy comprehensive power generation in china are introduced. the comprehensive evaluation of the current building energy saving environment using wind energy comprehensive utilization efficiency is given. the theoretical research results and practical application examples about building energy saving environment using wind energy are summarized. On the basis of this paper, some current hot issues that need further study are proposed in order to provide the basis for the wider application of wind technology in the architectural environment.

Research on multi-objective operation optimization of multi energy integrated service stations based on autonomous collaborative control

Multi energy integrated service stations have strong comprehensive energy and coupling properties, covering functional units such as substation, multi type energy conversion station, data center, distributed power generation, charging and replacement power station, wireless base station and so on. However, with the continuous improvement of the physical complexity of power grid information, there are still great theoretical and practical difficulties on how to build the operation optimization architecture of energy integrated service station and realize the organic integration of energy flow, data flow and business flow. The typical model forms of various equilibrium equality constraints and inequality constraints between stations and stations are established, and the multi-objective operation optimization model is established and solved. The results show that it improves the level of multi energy conversion, multi energy complementarity, comprehensive energy utilization efficiency, realizes the purpose of collaborative control optimization of multiple energy integrated service stations, and effectively promotes the maximum local consumption of renewable energy.

The Local Ordered Charging Strategy of Electric Vehicles Based on Energy Routers under Three-Phase Balance of Residential Fields

With the popularization of electric private cars and the increase of charging facilities in residential areas, disorderly charging will affect the power supply efficiency of their distribution transformers and the quality of electricity used by users in residential areas. In severe cases, it may even cause vibration of the power grid, causing serious three-phase imbalance problems such as single-phase burnout of transformers or insulation breakdown of household appliances. This paper analyzes the influencing factors of the unbalanced operation of each phase of the distribution transformer and the electrical load characteristics of typical residential areas. Based on the photovoltaic output of the station area, the charging and discharging capacity of the energy storage system, and the orderly charging plan of residential electric vehicles, a local orderly charging strategy for electric vehicles based on energy routers under the three-phase balance of the residential area is proposed. This strategy can realize the three-phase balance control of the distribution transformer. The effectiveness of the method is verified by a typical scenario example. The control method is changed to minimize the three-phase imbalance in residential areas and improve the low utilization rate of the distribution network and the comprehensive utilization efficiency of adjustable resources in residential areas.

Research on Cooperative Optimization Control Strategy of Multitype Energy Sources

With the increasing consumption of energy, the efficiency of energy utilization urgently needs to be further improved. At present, the coordinated optimization control of the integrated energy system of multiple types of cooling, heating, and power equipment is an important way to improve the comprehensive energy efficiency of the regional power grid and reduce the operating cost of the power grid. Aiming at this scenario, this paper establishes a fine energy storage model by analyzing the uncertainty of wind power output and considering the influence of low temperature and other conditions on the energy storage device in the energy storage side. On the load side, the influence of comprehensive demand response of electricity and heat on system operation is analyzed, and a combined cold, heat, and electricity supply system including renewable energy and energy storage device is established. Aiming at the optimal total cost of the integrated energy cooling and heating triple power system collaborative optimization control, the crow search algorithm is used to iteratively optimize the configuration model of the triple power system. The four models are considered in the article include groundless heat pump and energy storage, excluding joint demand response, including ground source heat pump and traditional energy storage model, excluding joint demand response, including ground source heat pump and fine energy storage model, excluding joint demand response, including ground source heat pump and fine energy storage model, taking into account the joint demand response. The simulation results show that the cooperative optimization control strategy of the combined cooling, heating, and power system with renewable energy and fine energy storage device model can enhance the system’s schedulable space, improve the comprehensive energy utilization efficiency, and have considerable economic benefits.

Thermodynamic analysis of a spectral-splitting hybrid PV-thermal system with LiBr/H2O absorption heat transformer

In order to improve the comprehensive utilization efficiency of solar energy, a spectral-splitting hybrid PV-thermal system integrated with LiBr/H2O absorption heat transformer (SSPVT-AHT) is proposed. The adopted solar spectral splitter decouples the photo-electric and photo-thermal conversion processes to achieve high temperature heat collection and high efficient electricity generation simultaneously. The absorption heat transformer is beneficially utilized to recover the surplus heat from the spectral-splitting PV-thermal subsystem to produce high temperature thermal energy. Through mathematical model establishment in MATLAB, a parameters analysis and thermodynamic evaluation are carried out. Then, the detailed energy/exergy distributions of the SSPVT-AHT system with and without parameter optimization are compared. Results show that the optimization of the main parameters, including the upper and lower cutoff wavelengths, LiBr/H2O solution concentration, cell temperature, absorber temperature, could improve the surplus heat utilization and boost the overall efficiency of the proposed system. Consequently, the overall energy efficiency reaches 59.26%, which is 25.56%-points higher compared with the situation without parameter optimization. Meanwhile, the overall exergy efficiency is 37.51% and the largest exergy destruction occurs in the solar cell, accounting for 73.98% of the total exergy loss, which mainly restricts the further improvement of system performance.

Performance analysis of combined cooling power based on small-scale compressed air energy storage system

In order to overcome the limitations of geological conditions, a test bench of small-scale compressed air energy storage (CAES) system based on pneumatic motor (PM) is proposed in this paper. As a key component of CAES system, the PM serves as an expander with the advantages of small size, lightweight, low cost, and convenient operation. The effect of the rotation speed, regulated pressure, and current on the key performance parameters (power output, compressed air consumption rate, and energy efficiency) are tested through experiments. In addition to the resulting output performance of the PM and generator, the energy efficiency of the PM, generator, and CAES system is analyzed. Given that the exhaust air from the PM has a refrigeration potential, the cooling power, cooling efficiency, and combined cooling power efficiency are also examined to improve the comprehensive energy utilization efficiency of the CAES system. The power output and energy efficiency of the PM and generator increase but eventually decrease with the rise of current and rotation speed. Under the lab-scale conditions, the maximum power output of the PM and generator are 989.21 W and 862.35 W, respectively. The maximum efficiency of the PM and generator is 9.83% and 87.19%, and the cooling efficiency and combined cooling power efficiency of the CAES system are 11.77% and 17.25%.

Research on System Optimization of Integrated Energy Park Based on Time-sharing Electricity Supply

Integrated energy system can improve the overall utilization efficiency of energy, and its advantages are remarkable. The integrated energy system covers various types of energy, such as electric energy, natural gas, and so on,which can realize the integration and complementarity of various energy sources in the park, which can improve the comprehensive utilization efficiency of the park system as a whole and reduce the cost of comprehensive energy use. In this paper, a multi-energy coupling energy system is constructed based on a typical park integrated energy system. By modelling the typical equipment in the system and using the time of using supply as the guiding strategy, the particle swarm optimization algorithm is used to optimize the typical days of the park, and the optimal operation strategy of the equipment in the system is obtained, which can significantly alleviate the peak and valley phenomenon between the system and the superior network.

Energy efficiency indicators for combined cooling, heating and power systems

Combined cooling, heating and power system is an effective technology for energy conservation and environmental protection, especially for buildings with multiple demands on electricity, cooling and heating load. Various energy indicators have been proposed for evaluating and optimizing the energy efficiency of combined cooling, heating and power systems, but previous studies have not yet clarified how to use them in a reasonable way that takes their specific merits into account. This paper aims to identify the underlying effects of three common energy indicators, including the primary energy rate, primary energy saving rate, and annual average comprehensive energy utilization efficiency, based on the optimized performance of combined cooling, heating and power systems with different typical configurations. This paper proposes three combined cooling, heating and power system configurations for an office building in Kunming to conduct a comparative analysis of three energy indicators. Two common operation strategy (the following thermal load and following electricity load) and the genetic algorithm are selected to performed single-objective optimization with energy indicator as target. The economic and environmental analysis is also carried out to show the impact of energy indicators on other indicators. The results show that, the indicators primary energy rate and primary energy saving rate have the same optimization effect of energy consumption when the system configuration and operation strategy are identical, as the difference between the primary energy rate values is not more than 1%, and the difference between the primary energy saving rate values is not more than 0.5%. The advantage of primary energy rate is that the difference between the primary energy rate values of combined cooling, heating and power systems and reference system could show whether carbon dioxide emissions are reduced, and the advantage of primary energy saving rate is that its value directly indicates whether the system achieves energy-saving or not. Furthermore, the annual average comprehensive energy utilization rate is not suitable for the single-objective optimization of combined cooling, heating and power systems. This study distinguishes the differences between indicators and the conclusions are of general significance which could provide valuable guidance for designers to select optimal energy indicators applying to the optimization design of combined cooling, heating and power systems.

Analysis of potential tapping and efficiency increasing measures of reservoir measures in late stage of oilfield development

In the process of oilfield development, with the continuous development of resource exploitation and oil transportation, the later exploitation is likely to reduce the potential energy of the oilfield, which has a serious impact on the oil exploitation. In order to make our oilfield development efficiency has been significantly improved, and effectively improve the comprehensive development and utilization efficiency of our oilfield, we must continue to use the oilfield potential enhancement technology. In the actual production process, we need to combine a variety of technologies, such as hydraulic transmission pressure fracture, water plugging, acidification and other technologies. Through the comprehensive utilization of these technologies, we can reduce the water content of comprehensive oil wells in the oilfield, effectively improve the production of the oilfield, bring greater economic benefits to the society, and promote the long-term, stable and healthy development of China’s oilfield.

Behavior of magnesium impurity during carbochlorination of magnesium-bearing titanium slag in chloride media

Abstract In this study, the phase composition, morphology, and element distribution of Mg impurities in a low-grade titanium slag and in its chlorinated residue after carbochlorination were identified using XRD, SEM-EDS, and MLA. Most Mg impurities existed as anosovite, rutile, titanaugite, and Ti silicate phases before the carbochlorination process. The thermodynamic analysis revealed that the chlorination tendencies of Mg, Ti, Ca, Fe, and Mn oxides in the original titanium slag was much higher than those of Si and Al oxides in the temperature range of 700–850 °C. In addition, the binary phase diagram analysis indicates that the magnesium chloride (MgCl2) byproduct formed Na2MgCl4 eutectic salts in the NaCl-based salt bath. The carbochlorination experiments of the Mg-bearing titanium slag show that the chlorination ratio of magnesium oxide was above 93% under the suitable industrial conditions used for the extraction of titanium from Mg-bearing titanium slag. In addition, the formation of Na2MgCl4 eutectic salts after carbochlorination was confirmed, indicating that the negative effect of MgCl2 on the chlorination process was effectively eliminated. The Mg impurities in the chlorinated residue existed as titanaugite, quartz, chlorite, and rutile phases. Furthermore, we found that the carbochlorination of Mg-bearing titanium slag in chloride media effectively improved the comprehensive utilization efficiency of the Mg-bearing titanium slag. We believe that the proposed carbochlorination mechanism of the Mg-bearing titanium slag will provide thorough understanding and useful guidance on the practical industrial application of Mg-bearing titanium slag.

Solar Assisted Heat Pump Water Heater Using Photovoltaic-Thermal Collector Evaporator and Its Building Energy Saving Performance

Solar assisted heat pump (SAHP) water heater based on photovoltaic/thermal collector evaporator (PV/T SAHP) can effectively improve the solar energy conversion efficiency by realizing the all-round application of solar energy, PV and photothermal. The heat generated in a PV/T collector evaporator is taken away by the refrigerant and supplied to the heat pump cycle, which can increase the heat pump’s evaporation temperature as well as its performance; meantime, the solar cell’s temperature decreases and the photoelectric conversion efficiency can be enhanced. The performance of PV/T SAHP system is studied theoretically and experimentally, and tested under different conditions. Conventional SAHP and uncooled solar panels are set as the control group. Compared with uncooled solar panels, PV/T SAHP can effectively reduce the temperature of solar cells and improve the photoelectric conversion power. The average error of the numerical simulation model is about 5%, which can meet the needs of engineering application. The optimum installation angle of the collector evaporator in Shanghai is calculated, which is 27°. The annual operation of PV/T SAHP in Shanghai is simulated and predicted. Among them, the average COP is 3.71, the average collecting efficiency is 0.71, and the average comprehensive utilization efficiency of solar energy is 1.04, which can maintain good working performance throughout the year.

Stochastic robust optimal operation of community integrated energy system based on integrated demand response

In the context of the rapid development of the energy internet, the traditional power demand response has gradually expanded to an integrated demand response. Multiple energy sources such as electricity, gas, heating, and cooling, are coupled and coordinated in integrated energy system, which is conducive to improving comprehensive energy utilization efficiency and providing more opportunities for the demand side to participate in system optimization. This paper focuses on the optimal operation of community integrated energy system (CIES). From the perspective of demand response, the horizontal complementary substitution and vertical time shift strategy of electric-gas-heating-cooling are introduced based on the interactive response characteristics analysis of multiple energy loads, and the cooperative complementarity and flexible transformation of multiple energy sources are taken into account to establish a stochastic robust optimal operation model of CIES based on integrated demand response. In this paper, a mixed-integer linear programming method is applied to solve the model, and the simulation results show that the proposed method can effectively reduce the operation costs and promote a balance between energy supply and demand while further tapping the potential of the energy demand side and achieving the economical, flexible and efficient operation of community integrated energy system.

Research on compound comprehensive energy evaluation and intelligent control optimization

Under the background of increasing energy demand, integrated energy system is an important way to promote the development of clean energy, support the efficient use of energy and energy saving and emission reduction. This paper firstly establishes a comprehensive energy system evaluation index model composed of three sub-models of economy, environment and energy. On the basis of this model, a comprehensive energy multi-objective optimization mathematical model with the lowest total cost, excellent environmental benefits and high comprehensive energy utilization efficiency is established, and the energy supply and demand allocation optimization method based on improved genetic algorithm is adopted for solution. The simulation proves the effectiveness of the proposed optimization model.