Applying energy-efficient motors in the petrochemical industry

Several US and Canadian utilities have implemented demand side management (DSM) programs for retrofitting energy efficient (EE) motors. This article examines some of the practical problems associated with this. When determining the energy savings achievable by retrofitting standard efficient (SE) motors with EE motors, the nominal efficiency difference between the SE and EE motors is often used. However, EE motors often operate at a higher speed or a lower slip in order to achieve the higher efficiency. This has an impact on centrifugal loads where the power consumed goes up as the cube of the speed, but the increased flow goes up only linearly with speed. Since the majority of loads in the petrochemical industry are centrifugal in nature (fans, pumps, and compressors), the impact of this speed differential on the actual efficiency difference is highlighted. Another consideration when retrofitting EE motors is the effect of operating voltage on efficiency. From end use metering it has been observed that most motors are supplied at above their rated voltage. The difference in rated voltage and realistic operating voltages also affects motor efficiency; however, SE and EE motors are affected differently. The impact of this operational difference on energy efficiency is also examined. Manufacturers' data is also presented to show relationships between efficiency, power factor, horsepower, and percentage load. As a consequence of this, the important question of downsizing of motors to operate closer to the smaller motor's maximum efficiency is considered     

放大转发协作中继链路的能效性能研究

针对采用放大转发和MQAM调制的源 中继 终端的通信链路,研究了在保证终端解调误码率低于给定值的条件下,调制速率对能量效率（EE）的影响以及各个系统参数对最优能量效率的影响。推导了射频电路消耗的最小功率,进而在同时考虑电路功耗和解调能耗时得到了能效性能的函数表达式。通过数学理论分析证明能效性能是调制速率的拟凹函数,并且当调制速率增大时,能效先递增再递减。当误码率增大时,最优能效严格递增,最优调制速率严格递减。当电路功耗递增时,最优能效严格递减,最优调制速率严格递增。当接收机ML解调初始能耗递增时,最优能效严格递减;最优调制速率严格递增。     

Advancing the state of energy equity metrics

Multiple stakeholders—ranging from regulators and developers to customer and community advocates—have roles to play in the transition to an equitable energy system. Metrics are an emerging area of importance for the operationalization of energy equity as they may guide investment and policy decisions that shape the energy system along this transition. This paper aims to advance energy equity metrics for use in regulation, planning, and operations of the electricity system within the United States. Metrics were surveyed from the literature and distilled to a set that identifies which stakeholders may be associated with which metrics. Established tenets of energy justice—distributive, procedural, recognition, restorative—were also identified for each metric, providing a link between energy equity in study and in practice. This means of organization is intended to enable discussion and collaboration among stakeholders, as the objectives embodied in energy equity metrics are often beyond the control of individual stakeholders. Further stakeholder discussion is necessary to determine which metrics are practicable, who will use them, and how they will be used to support energy equity.     

Focusing and improving traditional energy efficiency strategies

Energy efficiency can get us about half of the way to long-term climate goals. Traditional energy efficiency strategies — vehicle and appliance efficiency standards, building energy codes, utility energy efficiency programs and Energy Star — can provide about half the achievable efficiency savings (i.e., savings of about one-quarter of projected 2050 energy use). However, these strategies can benefit from a variety of improvements, and other programs and policies addressing buildings, transportation and industry can achieve substantial additional savings. These efficiency policies can be combined with strategies involving no- and low-carbon energy sources to put the United States on a trajectory toward meeting long-term energy and climate targets.     

天然气发动机燃烧性能模拟分析

运用AVL-BOOST软件分别建立天然气发动机和汽油机的燃烧模型,确定了两种燃料发动机的低热值和空燃比等参数后,进行了模拟分析。模拟结果表明,在同样的压缩比情况下,天然气发动机的动力性低于汽油机;天然气发动机的扭矩略低于汽油机,汽油机的加速性能和爬坡性能更好;天然气发动机的压力升高率低于汽油机,天然气发动机运转时噪声低,舒适性好;天然气发动机的放热率低于汽油机,天然气发动机的指示热效率比汽油机高,所以天然气发动机更经济;天然气发动机尾气中的CO、NOx和HC均低于汽油机,天然气发动机对环境的污染小。     

Measuring persistence of energy savings after COVID-19

Publicly funded energy efficiency projects require measurement to inform climate and energy policy, craft program budgets, and determine the cost-benefit ratios of different projects. One of the key inputs into cost-benefit analyses is the concept of an effective useful life, or EUL. This value, typically measured in years, lets programs and policy makers estimate how many years the energy savings will last. For most programs, this measurement is done based on manufacturing assumptions, i.e. the laboratory determined that an LED lightbulb would last for 10,000 h, or 15 years. New programs, using a methodology known as “advanced measurement and verification (AM&V)” measure the EUL using a survival analysis of the savings. We ask the question, “At what point will this project be savings less than 50% of what it saved on day 1.” We measure the energy consumption of a facility at the meter level to determine how much energy is being used compared to when the measure was installed. COVID-19 has thrown a wrench in the ability to compare energy use across years. Not only is there a disruption from COVID-19 directly, but entire industries have fundamentally changed the way that they operate their buildings and run their businesses. We are able to extract out the impacts of COVID for many of our building’s models, but not all. Using methods derived from independent, third-party evaluators, we have developed a new way to measure the ongoing persistence of energy savings using self-report data from participants at the project level, rather than at the savings level. Doing this will allow us to compare the data from pre-COVID with the new world full of post-COVID data, and to assess the true impacts of COVID on the energy efficiency industry’s most basic cost-effectiveness assumptions.     

柔性双工网络中基于图神经网络的能源效率联合优化方法

在绿色通信和双碳目标的背景下,提升网络能源效率(energy efficiency,EE)是当前无线通信系统设计和可靠运行的 关键技术之一。首先,针对柔性双工网络(flexible duplex networks,Flex-Net)的“和能源效率”最大化的问题,构建了一个具 有成对固定通信链路的网络;接着,鉴于图神经网络在通信网络资源优化中的优势,提出了一种新的基于图神经网络(GNN) 架构的柔性双工网络(GFlex-Net), 以联合优化“通信方向”和“传输功率”,达到网络能效最大化。仿真结果表明,与传统的算 法相比,所提出的架构有近乎最优的性能表现,达到穷举法性能的95%,但保持了较低的计算复杂度O(n²), 同时算法揭示了 GNN 在资源优化中面对样本复杂性、可扩展性和泛化能力方面的优势。     

Future energy goals for Maryland: Greenhouse gas reductions

Legislative requirements in Maryland set very robust goals for the implementation of energy efficiency by utilities. Significant energy savings has been achieved in all customer sectors and efficiency gains have been made over time in equipment and building construction. Looking forward, utilities should implement programs to promote energy efficiency with a greater emphasis on GHG reductions. Feasibility studies need to occur, but flexibility is key given changing codes and standards and market transformation.     

基于直流充电机的能效综合优化研究

直流充电机作为电动汽车充电设施,其能效问题愈发受到重视,国内外目前对于直流充电机能效的研究主要集中在提高能效计量精度和改善能效计量方法,缺乏对于直流充电机自身能效改善的研究,对此,文章主要在直流充电机的能效改善上进行了研究,通过分析各主要功能单元的功耗构成分布,重点对直流充电机的功率转换模块、控制器、液晶屏、辅助电源等部件进行了优化设计,提出相应的节能降损方案,对每个部分针对性的优化解决,以降低各个功能单元在实际运行中产生的能量损耗,并根据优化方案改善设计了直流充电机,通过实验验证了所提出的节能降损措施的有效性。文章研究结果对充电桩提高充电服务水平,改善能效问题具有重要意义,有利于电动汽车领域的长足发展,可以加快节能减排政策的落实。     

跨界思维在能源互联网中应用的思考与认识

针对中国双碳目标下能源绿色低碳转型面临的重大挑战,能源互联网利用跨界思维,破除能源系统中的各种壁垒,低成本地从电力行业之外寻找潜在资源,助力构建以新能源为主体的新型电力系统.能源互联网跨界思维应用有3个维度的要素:目标维度,包含绿色、低碳、安全、高效、优质等;对象维度,包含部门之间、主体之间、行业之间的跨界;手段维度,包含能量层打破物理壁垒实现互补资源互联、信息层打破信息壁垒打造灵活协同智慧、价值层打破价值壁垒构建多方共赢生态.分析了中国已实施的若干能源互联网项目在跨界思维3个维度的要素.探讨了学术层面学科跨界交叉融合若干方向的科学问题和关键技术.     

Design optimization of hydraulic energy storage and conversion system for wave energy converters

Wave energy collected by the power take-off system of a Wave Energy Converter (WEC) is highly fluctuating due to the wave characteristics. Therefore, an energy storage system is generally needed to absorb the energy fluctuation to provide a smooth electrical energy generation. This paper focuses on the design optimization of a Hydraulic Energy Storage and Conversion (HESC) system for WECs. The structure of the HESC system and the mathematical models of its key components are presented. A case study and design example of a HESC system with appropriate control strategy is provided. The determination of the ratings of the HESC system is also investigated in order to achieve optimal system energy efficiency.     

Design optimization of hydraulic energystorage and conversion system for waveenergy converters

Wave energy collected by the power take-off system of a Wave Energy Converter (WEC) is highly fluctuating due to the wave characteristics. Therefore, an energy storage system is generally needed to absorb the energy fluctuation to provide a smooth electrical energy generation. This paper focuses on the design optimization of a Hydraulic Energy Storage and Conversion (HESC) system for WECs. The structure of the HESC system and the mathematical models of its key components are presented. A case study and design example of a HESC system with appropriate control strategy is provided. The determination of the ratings of the HESC system is also investigated in order to achieve optimal system energy efficiency.     

解码转发中继系统能效性能研究

针对采用MQAM调制的半双工解码转发两跳中继通信链路,研究了在给定BER条件下,真实调制速率对系统能效性能的影响。首先从系统传输功耗出发,建立了传输信号所需发射功率的优化模型,据此推导出在给定BER约束下的最小发射功率。在能效问题中,设备本身的电路功耗已成为不可忽略的一部分,因此结合电路功耗给出系统能效表达式。基于凸优化理论,证明了能效性能是调制速率的拟凹函数,并分析了调制速率对能效性能的影响。理论分析和仿真结果表明：当调制速率增加时,系统能效先随之增加后又随之降低。另外,中继节点的位置也会对系统能效性能产生影响。     

能效评估计算器的设计与实现

能效评估对需求侧管理效果评价具有重要意义。针对工业与家庭用户的7种节能技改措施,设计了一种通用的能效评估计算器,给出了评估原则,详细介绍评估计算器的设计,可实现典型技改措施的初步能效评估。该计算器基于B/S架构,采用J2EE架构,结合JSP和Servlet技术,具有良好的伸缩性、扩展性和可移植性,可以预见其良好的工程应用前景。     

Assessing the relevance of barriers to energy efficiency implementation in the building and transport sectors in eight European countries

The paper maps and evaluates the main economic, institutional, and behavioural barriers to the implementation of energy efficiency in final uses. Barriers prevent the achievement of targets of energy efficiency policies and measures. Assessing the relevance of barriers can lead to their consideration in goal-setting by policy-makers either by reducing ambition or by incorporating solutions to mitigate barriers, We consider three main categories of barriers: economic, institutional, and behavioural ones, in buildings and transport sectors. In order to assess the relevance of each specific barrier in these categories, a survey to experts in eight Countries (Bulgaria, Germany, Greece, Estonia, United Kingdom, Italy, Belgium and Serbia) has been performed. The relevance of barriers is assessed by two levels of analysis: 1. their impact on policies and measures, and 2. their impact on the diffusion of key clean technologies and interventions in the two sectors. In the building sector, we find that the most relevant barriers relate to economic and behavioural categories. In the transport sector, we find that the most relevant barriers relate to institutional and economic categories. Economic barriers are also the most relevant in limiting the diffusion of technologies and interventions in both sectors. Results highlight the relevance of identifying and assessing barriers in order to improve policy design.     

含电—热—气—冷子系统的区域综合能源系统多场景优化调度

针对当前区域综合能源系统(RIES)研究中未详细考虑含电—热—气—冷子系统(PHGCS)协调运行效果的现状,研究计及能源子系统关键特征变量的RIES多场景优化问题。首先,基于能源集线器概念对以区域混合能源站为核心的能源耦合环节进行能源比例分配建模及分析,分别建立RIES中PHGCS数学模型。然后,提出考虑效率指标最大化、费用指标最小化、排放指标最小化及多目标综合性能指标最优的多场景运行模式,建立在不同负荷结构、多时段、多场景运行模式下的优化分析模型。其次,采用峰谷分时电价机制对RIES整体和分时段性能指标、子系统及耦合环节关键特征变量进行综合分析。最后,通过算例验证了该模型与优化方法的合理性和有效性。     

能源互联网背景下自动需求响应关键问题及展望

提高可再生能源利用比例以及能源的综合利用效率是未来能源系统发展的主要目标。随着能源与环境问题的不断突出,传统能源网络的资源配置能力逐渐不能满足未来能源系统的发展需求,能够实现"横向多源互补,纵向源网荷储协调"的能源互联网概念被提出。在能源互联网背景下,高度多元化和自动化的能源网络结构使得传统的电力需求侧响应(demand response,DR)将逐步向自动需求侧响应(automated demand response,ADR)的方向发展。首先对ADR的基本概念及其与能源互联网的协同作用进行阐述;其次,从规划、运行、控制、评价这4个维度分析了未来能源互联网中ADR的关键问题;最后,结合目前已有的研究成果和存在的问题,提出了推动ADR发展的相关建议。     

The public benefits of leasing energy efficient equipment

Utility-led leasing solutions can overcome several key barriers to customer adoption of new, efficient products that are overlooked by traditional energy efficiency programs or non-utility leasing programs, as a program proposed by Puget Sound Energy illustrates. By encouraging the installation of energy efficient equipment, a utility-led leasing program would generate significant benefits in terms of bill savings, enhanced comfort and quality of life, avoided energy costs, avoided capacity costs, and avoided emissions.     

电炉节能新途径的探讨

本文从改造电炉结构和调整炉料结构两方面探讨了电炉节能的新途径,并根据电炉冶炼的特点,通过理论分析和实验研究,提出了电炉节能的关键在于制备一种成本低,强度好、粒度均匀、比电阻高的新型复合炉料。经生产实践证明,这种复合炉料的效益十分显著。     

YY系列电容运转异步电动机能效限定值与节能评价值的研究

本文通过对国内通用电机之一——YY系列电容运转异步电动机进行选型、效率测试,建立测试结果数据表格,分析目前常用YY系列电动机效率情况,给出YY系列电动机能效限定值与节能评价值的参考值,所得结论对国家制定相关标准、推进我国节能认证具有很好的指导意义。