Dynamics of electromagnetic slip coupling for hydraulic power steering application and its energy-saving characteristics

To improve high-speed road feel and enhance energetic efficiency of hydraulic power steering(HPS) system in heavy-duty vehicles, an electromagnetic slip coupling(ESC) was applied to the steering system, which regulated discharge flow of steering pump to realize variable assist characteristic as well as uniquely transfer on-demand power from engine to steering pump. The model of ESC was established and the dynamic characteristics of ESC were presented by the way of simulation and experiment. Upon the layout of the assist characteristics, output torque of ESC was derived. Based on the ESC model, the output torque characteristics of ESC were simulated under steering situation and straight driving situation, respectively. The consistency of simulated ESC output torque and the one deduced from assist characteristics verifies the correctness of the ESC dynamic model. To illustrate energy saving characteristics of ESC-HPS, energy consumption comparison of ESC-HPS and conventional HPS was carried out qualitatively and quantitatively. It follows that the energy consumption of ESC-HPS decreases by 50% compared with that of HPS.

Optimal energy saving in DC railway system withon-board energy storage system by using peak demand cutting strategy

A problem of peak power in DC-electrified railway systems is mainly caused by train power demand during acceleration.If this power is reduced,substation peak power will be significantly decreased.This paper presents a study on optimal energy saving in DC-electrified railway with on-board energy storage system(OBESS) by using peak demand cutting strategy under different trip time controls.The proposed strategy uses OBESS to store recovered braking energy and find an appropriated time to deliver the stored energy back to the power network in such a way that peak power of every substations is reduced.Bangkok Mass Transit System(BTS)-Silom Line in Thailand is used to test and verify the proposed strategy.The results show that substation peak power is reduced by63.49% and net energy consumption is reduced by 15.56%using coasting and deceleration trip time control.

New design solutions for low-power energy production in water pipe systems

This study is the result of ongoing research for a European Union 7th Framework Program Project regarding energy converters for very low heads, and aims to analyze optimization of new cost-effective hydraulic turbine designs for possible implementation in water supply systems （WSSs） or in other pressurized water pipe infrastructures, such as irrigation, wastewater, or drainage systems. A new methodology is presented based on a theoretical, technical and economic analysis. Viability studies focused on small power values for different pipe systems were investigated. Detailed analyses of alternative typical volumetric energy converters were conducted on the basis of mathematical and physical fundamentals as well as computational fluid dynamics （CFD） associated with the interaction between the flow conditions and the system operation. Important constraints （e.g., size, stability, efficiency, and continuous steady flow conditions） can be identified and a search for alternative rotary yolumetric converters is being conducted. As promising cost-effective solutions for the coming years, adapted rotor-dynamic turbomachines and non-conventional axial propeller devices were analyzed based on the basic principles of pumps operating as turbines, as well as through an extensive comparison between simulations and experimental tests.

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.

Research on the Model of Long Term Generation Planning in Power Market Reform

With the deepening of China’s power market, bilateral transactions will continue to grow in large scale. The release of bilateral transactions locked more regulatory resources of the power grid, will directly affect the operation mode of the unit and the implementation of planned electricity. In the paper, considering the large-scale bilateral trade effect on the peak regulation of power grid, energy saving and emission reduction, power system security and other factors, and then putting forward the method of long term generation planning and annual planning model to adapt to the safe operation of power grid in China. In the model, the target is minimizing the monthly load rate deviation and the annual electric quantity deviation rate, the latter includes the capacity factor. In addition, the constraints include the monthly quantity of electricity, adjustable utilization rate deviation, load rate, reserve and key sections, etc. Through an example to verify the correctness of the model, the planning and power transaction results can satisfy the peak regulation of load, energy saving and emission reduction and safety operation of the power grid requirements.

Feasibility Analysis of the Operation Strategies for Combined Cooling, Heating and Power Systems (CCHP) based on the Energy-Matching Regime

Although numerous studies have considered the two traditional operation strategies:following the electric load(FEL)and following the thermal load(FTL),for combined cooling,heating,and power(CCHP)systems in different case studies,there are limited theoretical studies on the quantification methods to assess the feasibility of these two strategies in different load demands scenarios.Therefore,instead of a case study,we have undertaken a theoretical analysis of the suitable application scenarios for FEL and FTL strategies based on the energy-matching performance between systems'provision and users'demands.To compare the calculation models of energy saving rate(ESR)for FEL and FTL strategies in the left and right sub-regions of the energy-supply curve,a comprehensive parameter(^)that combines three inherently influential factors(off-design operation parameter,energy-matching parameter,and install capacity coefficient)is defined to determine the optimal installed capacity and feasibility of FEL or FTL strategies quantitatively.The results indicate that greater value of x contribute to a better energy saving performance,and FEL strategy shows better performance than FTL in most load demands scenarios,and the optimal installed capacity occurs when the load demand points were located in different regions of the energy-supply curve.Finally,taking a hotel in Beijing as an example,the value of the optimal install capacity coefficient is 0.845 and the FEL strategy is also suggested,and compared to the maximum install capacity,the average values of the ESR on a typical summer day,transition season,and winter can be enhanced by 3.9%,8.8%,and 1.89%,respectively.

基于过热蒸汽干燥开式制粉燃褐煤发电技术研究

针对高水分褐煤燃烧发电中存在的热效率低和低负荷稳燃困难等问题,提出了基于过热蒸汽干燥开式制粉系统的新型高效燃褐煤发电技术,该技术采用基于汽轮机抽汽加热的过热蒸汽干燥开式制粉系统,保证了制粉系统的运行安全性,提高了燃烧系统的运行灵活性,实现了制粉系统与锅炉主机的运行解耦,并综合解决了褐煤锅炉炉温低、热效率低的等问题。以600 MW超临界燃褐煤机组为例,对采用该技术的热力系统进行了仿真,分析了其节能与环保效益。研究结果表明,该技术通过对锅炉与汽轮机整体热力系统的综合优化,将汽轮机回热系统扩大至高水分煤的干燥过程,同时梯级回收锅炉排烟废热和制粉乏汽废热至汽轮机回热系统,可获得较为显著的节煤效益。同时,该技术不仅可由节煤相应减少各类污染物及CO_(2)排放,还可回收大量水资源,有望实现零水耗电厂。

110 k V变电站光伏节能减排系统研究

基于A 110 kV变电站,探讨了光伏节能减排系统的设计思路和应用效果。构建的光伏节能减排系统借助光伏发电技术,将太阳能转化为电能,为变电站提供清洁能源,降低对传统电网的依赖,同时有效降低成本,实现节能降耗目标,这对于促进中国电力行业健康、可持续发展极为有利。

分布式光伏接入火电厂厂用系统的安全经济性分析

传统火电在当前能源结构转型的背景下将逐步转型为网源支撑和系统调节,与分布式光伏的厂用发电耦合是火电企业实现降本增效的一种有效尝试。但因厂用非统调电源的接入暂无相关规程指导,在系统安全稳定方面缺乏评估策略和实证参考。为此,以西北某火电厂的火电光伏互补供能系统为例,分析了其运行特点并给出了稳定性评价的技术框架,在不同机组、并网等级和最小光伏单元布置的实例中,讨论了静态潮流、暂态稳定和电能质量等应用评价问题,计算得到本例场站下火电机组厂用电减损效能实现了18%~42%的提升。该结论对火电厂应用“分布式光伏接入厂用系统”的发电技术模式有着典型的借鉴意义。

基于嵌入式系统的新能源汽车智能节能控制系统设计

随着环保意识的增强和能源危机的加剧,新能源汽车作为一种绿色、可持续的交通工具,受到了广泛关注。为进一步提高新能源汽车的能源利用效率,智能节能控制系统成为了研究的热点。该文首先介绍嵌入式系统在新能源汽车中的应用现状和发展趋势。接着,详细介绍智能节能控制系统的设计原则和方法,包括能量管理、动力分配、驾驶行为识别和环境感知等方面的智能控制策略。最后,通过实际案例和试验结果来验证该系统的性能和效果,并对未来的发展方向和应用前景进行展望。研究成果对于新能源汽车的节能控制和能源管理具有一定的理论和实际应用价值,可为新能源汽车的智能化发展提供参考。

某机修工程光储直柔系统方案探讨

在分析光储直柔系统原理基础上,以某新建机修工程智慧低碳建筑为例,构建光储直柔微网系统和光储充微网系统,并对两种方案进行设计对比分析探讨,以实现新能源的更好利用。

热工仪表及自动控制系统对火电机组节能降耗的影响研究

随着社会和时代的飞速发展,绿色、节能、环保已经成为我国社会发展的主要研究课题,电力行业在生产和运营过程中,也需要采取节能措施,降低电力企业的能耗。火电机组大多采用燃煤发电,在实际运行过程中增加了能源消耗,而将热工自动控制系统有机地应用到火电机组的运行过程中,能够实现良好的节能降耗效果,提高电力企业的生产效益和环境效益。基于此,本文主要分析热工仪表以及自动控制系统对火电机组节能降耗的影响。

城市轨道交通同相储能供电系统的节能运行优化策略

[目的]针对广州地铁18号线采用的组合式同相供电装置,为了解决同相牵引供电系统中存在的再生制动能量利用率低的问题,需对同相储能供电系统的节能运行优化策略进行研究。[方法]以牵引变电所的日电费成本最低为目标,平衡节点功率,以供电装置与储能装置运行特征为约束,建立了同相储能供电系统节能优化模型。以广州地铁18号线某牵引变电所负荷过程实测数据为依据,对城市轨道交通牵引负荷过程进行分析,利用CPLEX商业规划求解器对该模型求解,最终获得同相储能系统最优能量管理方案。[结果及结论]超级电容接入组合式同相供电装置直流环节的储能供电系统,通过超级电容对牵引负荷的削峰填谷作用,能提高牵引供电系统再生制动能量利用率,减小城市轨道交通运营商的电费成本。试验结果表明,相比传统的同相供电系统,采用接入超级电容的同相储能供电系统可使得再生制动能量利用率达到92.88%,使日电费成本降低9.65%,节能效果显著。

焓差控制法在某核电厂空调系统中的应用

介绍了焓差控制法在核电厂空调系统中的应用:在满足系统功能的前提下,通过优化送风温度范围来扩大空调系统运行工况范围以达到节能效果。介绍了系统最小新风量和冬、夏季工况点的设定,空气比焓的计算及系统控制逻辑的实现。运行结果表明,空调系统运行稳定且节能效果良好,可为核电厂空调系统应用焓差控制法提供参考。

抽油机节能降耗技术措施探析

旨在探究抽油机节能降耗技术措施,通过对能耗数据的分析,研究动力系统、结构系统和运行管理三个方面的节能技术,利用实验和仿真分析验证效果,为抽油机节能降耗提供相关理论和技术支撑。本研究对于推动油田开采工艺的节能降耗和可持续发展具有一定的理论和实际指导意义。

煤矿供电系统节能优化控制策略研究

旨在研究煤矿供电系统的节能优化控制策略。通过对供电系统的分析和改进,提出了一种有效的节能方法。煤矿供电系统节能优化的意义在于减少能源消耗、降低环境污染和提高能源利用效率。通过实施建设智能化供电系统、选择节能型设备和合理调整电网结构等策略,实现煤矿供电系统的节能目标。

类直流冷却水系统在热电厂的工程应用

鉴于热电厂冷却水量小、锅炉补给水量大的特点,提出类直流冷却水系统。通过数学归纳法和热量平衡法可知,类直流冷却水系统不但能够保证冷却水系统的安全稳定运行,而且可以通过利用废热的方式提高除盐水处理系统的出力。此外,经过经济效益分析表明,相比于设置机械通风冷却塔的循环冷却水系统,类直流冷却水系统具有经济、节能、节水等优势,同时对热电厂的废水零排放也有着较大意义。

煤矿供电系统节能降耗技术研究

分析了煤矿供电系统中储能技术和智能控制技术的应用,通过对煤矿供电系统节能降耗优化方案的研究,提出了供电系统智能化建设。基于煤矿供电系统的实际情况,考虑供电系统的各种因素,对智能化供电系统的适用性进行了评估,并进一步提出了供电系统节能降耗的优化措施,以提高供电系统的实用性和效率。

汉口中华全国总工会旧址电气修缮改造设计分析

以汉口中华全国总工会旧址建筑物为例,介绍文物建筑物电气修缮设计的方法和过程,对供配电系统、火灾自动报警系统、防雷接地系统、节能改造等电气修缮改造设计要点进行重点分析,并对项目实施中遇到的相关问题提出相应解决方案。