Improving energy utilization efficiency of electrical discharge milling in titanium alloys machining

Electrical discharge milling(ED-milling) can be a good choice for titanium alloys machining and it was proven that its machining efficiency can be improved to compete with mechanical cutting. In order to improve energy utilization efficiency of ED-milling process, unstable arc discharge and stable arc discharge combined with normal discharge were implemented for material removal by adjusting servo control strategy. The influence of electrode rotating speed and dielectric flushing pressure on machining performance was investigated by experiments. It was found that the rotating of electrode could move the position of discharge plasma channel, and high pressure flushing could wash melted debris out the discharge gap effectively. Both electrode rotating motion and high pressure flushing are contributed to the improvement of machining efficiency.

Electricity as an Energy Vector: A Performance Comparison with Hydrogen and Biodiesel in Italy

This study presents a comparative analysis of electricity, hydrogen, and biodiesel as energy vectors, with a focus on powering an aluminum smelter in southern Italy. It evaluates these vectors in terms of efficiency, land requirements for carbon-neutral energy production, and capital expenditure, providing insights throughout the entire supply chain (upstream, midstream, and downstream) into their feasibility for industrial applications. The research reveals that biodiesel, despite being carbon neutral, is impractical due to extensive land requirements and lower efficiency if compared to other vectors. Hydrogen, downstream explored in two forms as thermal power generation and fuel cell technology, shows lower efficiency and higher capital expenditure compared to electricity. Additionally, green hydrogen production’s land requirements significantly exceed those of electricity-based systems. Electricity emerges as the most viable option, offering an overall higher efficiency, lower land requirements for its green production, and comparatively lower capital expenditure. The study’s findings highlight the importance of a holistic assessment of energy vectors, considering economic, environmental, and practical aspects along the entire energy supply chain, especially in industrial applications where the balance of these factors is crucial for long-term sustainability and feasibility. This comprehensive analysis provides valuable guidance for similar industrial applications, emphasizing the need for a balanced approach in the selection of energy vectors.

Managing System Losses to Improve Energy Efficiency within the Electricity Company of Ghana (ECG) Limited

The inability to achieve the target of universal access to electricity is influenced by several factors including funding limitations, the use of obsolete equipment, power theft, and system losses confronting the electricity distribution services of the Electricity Company of Ghana Limited (ECG). The study assessed the components of system losses within the ECG by determining and computing the percentage of system losses within ECG, examining the causes of both commercial and technical losses in ECG, and determining ways to improve energy efficiency by reducing system losses in the most cost-efficient manner. The study adopted deductive reasoning and a quantitative approach to guide data collection and analysis of the research output. A sample of 345 technical and non-technical staff of ECG in the Greater Accra Metropolis was selected from a population of 2500. Purposive, simple random, and cluster sampling techniques were used in identifying and accessing respondents for the study. Descriptive statistics were applied to measure central tendency and degrees of dispersion and the Relative Importance Index (RII) to predict criterion and predictor variables. The impact of low voltage network losses can adversely contribute to technical losses (20%) and reduce energy efficiency in power or electricity distribution companies. Non-technical losses are mainly caused by illegal connections, meter problems, and billing problems. Each of the non-technical losses contributes a maximum of 10% to system losses. Contributors to system losses at ECG are ranked first for power theft and least for lack of incentives. System losses at ECG include metering inaccuracies, bad workmanship, unmetered supply, and lengthy distribution lines, each recording a mean value of above 3.5. Measures to improve monitoring of the networks and systems at ECG and discourage power theft should include an extensive quantification, patrolling, and inspection of the entire network to assess the extent of the network and conditions relevant for the placement of systematically planned maintenance programmes.

Industrial Electric Energy Efficiency and Influential Factors in China

As traditional single-factor electricity intensity can not reveal the real electricity consumption efficiency accurately, this study applies the data envelopment analysis (DEA) approach to calculale the total-factor electricity consumption efficiency of China’s 33 industrial sectors from year 1998 to 2007, and uses the Tobit model to analyze the influential factors of electric energy efficiency. The result shows that China’s industrial electricity efficiency is universally low. Further study shows that industrial structure and technological progress have positive influence on consumption efficiency, while industry concentration and electricity price have negative influence on consumption efficiency. The effect of property right structure is fluctuated. Therefore, to optimize industry structure, promote technological progress, maintain competition, and deepen the reform of electricity price are beneficial for the improvement of electric energy efficiency.

Energy Consumption Analysis and Optimization of Electric Submersible Pump System

Electric submersible pumps account for a considerable proportion in the development of the Bohai Oilfield. Improving the system efficiency of the electric submersible pump wells, ensuring that the units operate in the high-efficiency zone, is essential. Analysis shows that the efficiency of the electric submersible pump system depends on the wear and tear of each component of the submersible pump equipment, the setting of operational parameters, and more importantly, the production status and daily management level of the oil well. Therefore, improving the structural performance of the submersible pump product, optimizing the parameters setting of the oil well, strengthening daily management, establishing a scientific management system, and improving the production management process and system can effectively improve the production efficiency and economic benefits of the oil well, and further achieve the goal of energy saving and emission reduction. In addition, it is necessary to actively promote the concept and technology of energy saving and emission reduction, encourage oilfield enterprises to explore effective measures to reduce the energy consumption of the electric submersible pump system by strengthening the scientific management system, and achieve a green, low-carbon, and high-quality development of oilfield production to achieve the unity of economic benefits, social benefits, and environmental benefits. This article applies the above measures in the P oilfield to achieve energy optimization of submersible electric pump systems, reducing the daily power consumption of single well submersible electric pump systems by 371 kWh per day, increasing the submersible electric pump's lifespan by 200 days, generating considerable project benefits.

Simulation of District Cooling Plant and Efficient Energy Air Cooled Condensers (Part I)

In hot arid countries with severe weather, the summer air conditioning systems consume much electrical power at peak period. Shifting the loads peak to off-peak period with thermal storage is recommended. Model A of residential buildings and Model B of schools and hospitals were used to estimate the daily cooling load profile in Makkah, Saudi Arabia at latitude of 21.42°N and longitude of 39.83°E. Model A was constructed from common materials, but Model B as Model A with 5 - 8 cm thermal insulation and double layers glass windows. The average data of Makkah weather through 2010, 2011 and 2012 were used to calculate the cooling load profile and performance of air conditioning systems. The maximum cooling load was calculated at 15:00 o’clock for a main floor building to a 40-floor of residential building and to 5 floors of schools. A district cooling plant of 180,000 Refrigeration Ton was suggested to serve the Gabal Al Sharashf area in the central zone of Makkah. A thermal storage system to store the excess cooling capacity was used. Air cooled condensers were used in the analysis of chiller refrigeration cycle. The operating cost was mainly a function of electrical energy consumption. Fixed electricity tariff was 0.04 $/kWh for electromechanical counter, and 0.027, 0.04, 0.069 $/kWh for shifting loads peak for the smart digital counter. The results showed that the daily savings in consumed power are 8.27% in spring, 6.86% in summer, 8.81% in autumn, and 14.55% in winter. Also, the daily savings in electricity bills are 12.26% in spring, 16.66% in summer, 12.84% in autumn, and 14.55% in winter. The obtained maximum saving in consumed power is 14.5% and the daily saving in electricity bills is 43% in summer when the loads peak is completely shifted to off-peak period.

Impact of Implementation Energy Efficient Appliances in Palestinian Market

Recently, Palestine has been willing to improve its energy efficiency action plan and policies. As the Electrical demand for energy is increasing in Palestine, improving energy efficiency can be considered as an efficient way to achieve reductions in energy consumptions. In this respect, energy efficiency action plan and its strategies must be designed to overcome existing market barriers against using energy efficient appliances in residential and commercial sectors in Palestine. This study provides background on the benefits of stakeholders and steps needed to support energy efficiency standards and labeling in Palestine. Furthermore, this study attempts to predict the techno-economic impact of implementing high efficient electrical appliances in Palestine. Survey-based analyses from 300 households were conducted in 2019 to estimate residential sector electrical appliances usage, behavior and their knowledge in electrical appliances labels and standards, the study aims also to estimate the perception and willingness of Palestinian householders to shift towards more energy efficient choices. The study will focus on 8 electrical appliances that constitute a major share of the electricity used within households and commercial sectors in Palestinian market.

Deployment of Electric Induction Technologies into Cooktops Plates as a Part of Energy Sustainability

For a long time now, humanity has been facing the phenomenon known as “climate change”, a major challenge of which we must be aware of what we are doing so as not to affect ourselves or future generations. It is evident that, if what is sought is a sustainable energy future, the current energy model implemented in certain countries and regions of the world is not the most adequate and makes the achievement of this goal unfeasible. This situation threatens to greatly alter our ecosystems and our social structures, and one of the key actions to mitigate it is, undeniably, the generalization of the use of renewable energy sources;and specifically, the non-conventional sources, referring to solar and wind, technologies that comply with the principle of energy complementarity;however, there are other possible solutions such as the deployment of programs that consider efficient cooking technologies;involving with it is everything related to energy security and equity, as well as environmental protection. In this article, as a technology to be considered to reduce and mitigate the Greenhouse Gases (GHG) emissions, an analysis of the efficiency assessment of electric induction cooktops and the determination of their potential energy savings are carried out. The impact of these results is taken into consideration and a series of conclusions and recommendations for improvement are issued.

水冷冷水机组热回收的节能分析

本文首先介绍了夏热冬暖地区生活热水系统常用的三种热水供给方案,并对其所用的热源机组进行能效分析及能耗分析,把空调制冷与生活热水作为一个整体,具体计算了三种方案热源机组的单位制热量耗电指标,这一指标的计算结果表明了回收水冷冷水机组的冷凝余热用于生活热水系统节能效果明显,且在此基础上推导出不同环境温度下运行经济性最佳的水冷冷水机组热回收温度,进而通过工程实例广东佛山某酒店项目的生活热水系统热源机组年能耗计算佐证之。本文量化分析了水冷冷水机组热回收的节能效果以及热回收温度对节能效果的影响,以期为水冷冷水机组热回收的应用及运行提供有益的参考和指导。

计及氢能高效利用和热电灵活输出的综合能源系统源荷灵活运行策略

为进一步发挥氢能高效利用优势,构建绿色低碳能源系统,提出一种计及氢能高效利用和热电联产灵活输出的综合能源系统源荷灵活运行策略。首先,对源侧供能模型进行两方面改进:一是引入含风电制氢、燃气混氢、多能用氢和储氢的氢能利用模型,并考虑到电解水和甲烷化反应过程中的热量散失情况,引入热量回收装置,构建计及热量回收的氢能高效利用模型;二是针对常规热电联产灵活性不足的问题,构建含电锅炉和有机朗肯循环的热电灵活输出模型,以解耦常规热电联产“以热定电”和“以电定热”限制。其次,在荷侧引入含可转移、可削减和可平移的电、热柔性负荷,以缓解电、热负荷峰谷差,并与源侧相结合,形成源荷灵活运行模型。最后,综合考虑阶梯型碳交易成本、设备运行维护成本、弃风成本以及购能成本,建立综合能源系统源荷灵活优化运行模型。采用CPLEX求解器对所提综合能源系统源荷灵活运行模型进行求解,并设置不同场景进行对比。结果表明,相比常规氢能利用模型,考虑所提计及热量回收的氢能高效利用模型时,系统的总成本、碳排放量分别降低了1.92%、4.22%,并且引入热电联产改进模型后,其总成本、碳排放量可进一步降低4.08%、7.32%,实现系统低碳、经济和灵活运行。

Evaluation of energy transfer and utilization efficiency of azo dye removal by different pulsed electrical discharge modes

The degradation of an azo dye, acid orange 7 (AO7), caused by different high voltage pulsed electrical discharge modes (spark, streamer and corona discharge) induced by the various initial conductivities was investigated. A new type of pulsed high voltage source with thyratron switch and Blumlein pulse forming net (BPFN) was used. The typical discharge waveforms of voltage, current, power, pulse en-ergy and the pictures of spark, streamer and corona discharge modes were presented. The results in-dicated that pulsed electrical discharges led to complete decolorization and substantial decrease of the chemical oxygen demand (COD) of the dye solution. The main intermediate products were monitored by GC-MS. The discharge modes changed from spark to streamer and to corona discharge, and the streamer length decreased with the liquid conductivity increasing. At a constant input power, the peak voltage, peak current, peak power and energy per pulse of the three discharge modes ranked in the following order: spark > streamer > corona. The effective energy transfer efficiency of AO7 removal was higher for spark discharge (57.2%) than for streamer discharge (40.4%) and corona discharge (27.6%). Moreover, the energy utilization efficiency of AO7 removal for spark discharge was 1.035×10^(-9) mol/J, and for streamer and corona discharge they were 0.646×10^(-9) and 0.589×10^(-9) mol/J. Both the energy transfer efficiency and the energy utilization efficiency of spark discharge were the highest.

一级能效电工钢片比总损耗的精确测量与仿真分析

针对国标爱泼斯坦方圈法测量新一级能效硅钢片比总损耗结果的不确定性问题,本文提出了一种工频下基于双爱泼斯坦方圈的新一级能效硅钢片比总损耗测量方法。通过双爱泼斯坦方圈法测量硅钢片的比总损耗,分析并修正了测量方法中的误差,实现了对爱泼斯坦方圈测量时接缝区和均匀区的损耗分离,并分析了接缝区比总损耗对爱泼斯坦方圈测量结果的影响机理。建立了爱泼斯坦方圈有限元模型,对其接缝区和均匀区的损耗进行研究,仿真结果与双方圈法测量结果吻合,验证了本文提出的新一级能效超低损耗薄硅钢片的比总损耗时测量方法的有效性和准确性。测量和仿真结果表明,基于双方圈法测量薄硅钢片比总损耗的结果比单方圈法测量的结果更精确。本文提出的测量和修正方法可用于一级能效薄硅钢片损耗特性的精确测量。

直接接触式固体蓄热电锅炉的能效分析

能效评价是热源能源利用效果的重要体现,传统的固体蓄热电锅炉由于空气的比热容小且需要多级换热,会降低系统的换热效率,直接接触式固体蓄热电锅炉技术提高了热源的换热效率,但缺乏一套完备的能效评价标准。使用(火用)分析法展开分析,掌握热源运行参数及能量转换关系,确定(火用)分析模型并计算,获取其能效评价指标;再运用集值统计法确定指标权重,模糊综合评价确定其评分及等级,形成该直接接触式电锅炉的能效评价体系;最后结合热力学理论分析并利用具体实验验证该评价体系的合理性,为直接接触式固体蓄热电锅炉技术改进及推广发展提供参考。

基于TRNSYS的太阳能-电能互补采暖系统研究

针对我国北方农村地区冬季采暖污染严重、碳排放量大等问题,文章以沈阳市某地区典型农村单体式住宅为研究对象,综合考虑太阳能、电能,提出2套清洁供暖方案。首先对太阳能集热器的集热倾角和面积的选择进行优化,然后选取沈阳市供暖季温度较低的2天,根据天气情况分别作为晴天与阴天典型日,最后利用TRNSYS软件对供暖方案在典型日天气条件下模拟运行。结果表明在典型日天气条件下本研究提出的2种供暖方案均满足环保、室内温度适宜等采暖需求,且太阳能集热器+变频电磁采暖炉供暖方案更为节能。

夏热冬暖地区基于性能模拟的新型电动格栅构件遮阳效果研究

夏热冬暖地区对于建筑遮阳有显著需求。以广州某建筑为例,运用Ecotect软件进行太阳入射辐射和采光系数计算,运用Energyplus进行区域理想负荷室外空气总制冷计算,分析新型电动格栅构件的遮阳节能效果。并将其与三种基本遮阳方式(外遮阳、内遮阳和中间遮阳)、新型电动格栅构件与水平板结合的综合式遮阳方式进行对比,分析各自遮阳和降低能耗的效果差异。模拟发现,将新型电动格栅构件与水平板结合起来的综合式遮阳效果最佳,且具有更强的灵活性,可为夏热冬暖地区遮阳设计提供一定参考。

高速电驱系统的油量和效率关系研究

新能源汽车的高速发展,推动了电驱动系统技术的快速迭代升级,驱动电机的转速越来越高。为研究电驱动系统高速化对系统效率的影响,文章深入探究了高速运行状态下润滑油量与电驱系统效率之间的关系。以一款120 kW电驱系统为研究对象,首先利用Masta-Nano FlowedX软件进行不同扭矩、不同转速下的效率仿真分析,随后,通过台架实验对仿真结果进行验证,探究了润滑油量、转速与电驱系统运行效率之间的关联性,并确认了理论分析与实际应用的一致性。文章提出了一种基于实际工况的优化策略,对电驱动系统优化设计具有一定的理论指导价值,也为实际操作提供了方法论参考,对推动新能源汽车相关技术的发展具有重要影响。

考虑分区域动态电价机制引导的电动汽车充电优化策略

为应对大规模电动汽车无序充电引起的配电网运行损耗增加问题,提出一种分区域动态电价机制引导的电动汽车(electric vehicle,EV)充电优化策略。该动态电价机制是根据不同区域内的负荷特点建立不同的动态电价,从而优化对应区域的EV充电。其中商业区建立计及充电站充电总功率的动态电价模型,居民区和办公区采用计及风光出力的动态电价模型。同时,提出充电效益系数模型以提升在居民区和办公区用户的充电时间满意度。最后,在IEEE33节点系统上进行仿真验证。结果表明,所提出的基于分区域动态电价机制的EV充电优化策略能够在保证车主利益的同时,降低网损、提高配网电压质量、促进风光消纳以及提升配网的经济性。

CNT/PVA@碳布膜的光电联合驱动界面蒸发性能研究

利用电能辅助的太阳能驱动界面蒸发技术是提高淡水产量的一个有效途径,但是如何绿色高效地获取淡水仍是一个挑战。利用带有孔洞的亚克力板作为支撑装置,在碳布上喷涂碳纳米管(CNT)和无水乙醇的混合溶液作为光热电热膜(CNT/PVA@碳布),与隔热装置和供水通道组成一个高效的界面蒸发系统。蒸发性能测试结果表明,该蒸发系统在1个标准太阳光照射下净蒸发速率达到1.5 kg·m^(-2)·h^(-1),而在与2 A电流的联合作用下,净蒸发速率高达5.08 kg·m^(-2)·h^(-1),比仅在1个标准太阳光照射下和仅提供2 A电流的蒸发速率之和高出0.6 kg·m^(-2)·h^(-1)。此外,这种蒸发系统构造简单易于规模化,为绿色高效地提高淡水产量提供了一个新的思路。

多能联供协同干燥的压缩空气储能

【目的】为探究压缩空气储能系统(compressed air energy storage system, CAES)在冷热电场景下的工程应用,提出了一种用于木材干燥的CAES。【方法】首先搭建了CAES及其数学模型;其次分析了木材高温干燥和除湿干燥模式的能耗,通过模拟试验探究了CAES的冷热电联产特性;最后将系统产出的冷热电能与两种干燥模式的能耗负荷匹配,并进行经济性分析。【结果】储能系统采用补能预热,水流量为1 kg/s时产生最大制冷量和级间热量;当换热冷却水流量为3.3 kg/s时,木材干燥综合能效最高;高温干燥方案投资静态回收期稍微低于除湿干燥方案。【结论】本研究结果为木材干燥企业的能源转型提供参考,同时为压缩空气储能系统的工程应用开辟了新方向。