加热器端差对1000MW机组热经济性影响的数学模型研究

在凝汽系数法基本理论的基础上定义了凝汽系数变动率的概念.采用凝汽系数法,从反平衡的角度出发,针对不同型式的加热器,通过严密的数学推导,得出了加热器端差对经济性影响的凝汽系数模型.以超超临界参数1 000MW机组为研究对象,运用所建立的凝汽系数模型定量分析了表面式加热器端差对该机组热经济性的影响,并将凝汽系数法模型与等效热降法模型的计算结果进行了对比,结果表明,凝汽系数法具有模型简捷、结果准确的特点.     

抽汽压损对机组热经济性影响的凝汽系数模型

采用凝汽系数法,从反平衡的角度出发,针对不同型式的加热器,通过严密的数学推导,得出了加热器压损对经济性影响的凝汽系数模型.以超超临界参数1 000MW机组为研究对象,运用所建立的凝汽系数模型定量分析了抽汽压损对该机组热经济性的影响,并将凝汽系数法模型与等效热降法模型的计算结果进行了对比,结果表明,凝汽系数法具有模型简捷、结果准确的特点.     

天津市农村沼气生物质能发展概述

以天津市9个区县作为研究对象,定量分析农村沼气生物质能两大类资源——农作物秸秆和畜禽粪便的状况,根据不同农作物谷草比系数、折算标煤系数以及畜禽粪便综合利用系数,计算出天津市农村生物质能耗占全市新能源消费总量和农村生产、生活能耗比例。同时,详细分析了天津市农村沼气生物质能发展的五大利用模式,并且对全市农村户用沼气工程进行了环境效益分析。结果表明,天津市武清区、宝坻区、蓟县和静海县农作物秸秆资源量在天津市排名分列前4位,宁河县、静海县、武清区和宝坻区畜禽粪便资源占有量分列天津市的前4名,全市农村户用沼气池替代秸秆减排CO2达到1万多t。     

转子动平衡的几个优化算法

介绍了转子动平衡的影响系数法，影响系数余量法，定相位角最佳算法，单平面加重的优化搜索法及优化影响系数的算法及其MATLAB语言的实现。数值算例验证了各程序的正确与有效，同时说明通过计算得到的多种配重方案，给平衡工作者提供了宽广的选择空间，有利于提高平衡工作的质量、效率和降低成本。     

太阳辐射下户外空间界面温度的预测模型和方法

用表面温差方法建立户外空间界面温度的预测模型,然后提出用反应系数法计算空间界面的吸热系数,进而利用室外气候参数实现界面温度的预测,最后结合实测气候资料和某一居住小区建筑状况,利用周期性反应系数法对几种界面的温度进行了预测计算,结果表明数值计算与实测有相当好的一致性,最大相对误差不超过6%,预测模型和计算方法为分析边界面材料和颜色以及建筑物布局对界面温度的影响提供了方便。     

普通高等院校单位电耗定额及计算方法

1范围 本标准规定了普通高等院校在日常教学、科研工作中所消耗的单位综合电耗定额及计算方法。 本标准适用于普通高等院校用能系统中用于日常教学、科研工作的耗电量的计算与考核。     

曲轴疲劳可靠度分析

曲轴强度分析采用安全系数法不能定量反映出安全可靠程度。由于工作应力和疲劳强度均为随机变量,必须运用概率统计方法进行强度分析,可靠性指标能尽量反映零件安全可靠程度。有限元发展,为内燃机结构强度精确计算提供了条件。本文采用四分之一曲拐有限元模型分析曲拐应力分布,找出危险区域;将应力看成载荷及材料强度函数,运用有限差分法,根据应力—强度干涉理论,借助哥德曼图计算曲轴的可靠度。作者认为在曲轴强度分析中可靠性分析比安全系数法更合理、可靠和接近实际。     

全力做好固定资产投资项目节能评估和审查工作

<正>近年来,武汉市节能监察中心积极协助政府部门完善能评制度、规范操作流程、强化监察评价,加强能评事前、事中、事后全过程管理,取得了良好效果。一、武汉市能评工作的基本情况武汉市能评工作始于2010年10月,市发展改革委出台了《固定资产投资项目节能评估和审查办法(试行)》,2012年制定了《固定资产投资项目节能评估和审查工作指南》,明确了能评工作的实施部门、工作流     

能评与环评之间还存在很大的差距

正与环评相比,能评基础工作仍然相对薄弱。能评的发展需要建立像环评那样的人员资质和单位资质制度。环评制度在我国实施以来,取得了显著的成效,行业内获得很高的权威性,为保护环境做出很大的贡献。与之相比,能评还存在比较大的差距,还需从各方面改进和加强。     

直流锅炉热态水动力调整方法研究

针对现场实际情况 ,在研究大量文献基础上 ,提出了一种水动力调整的新方法———压降系数法。压降系数法能把阻力系数对流量和压降的影响进行综合考虑 ,通过压降系数法的数学模型来求解各个回路节流压降系数或阻力系数 ,进而确定各节流阀开度或节流阀板的孔径 ,实现水动力调整的一次到位。在Mi crosoftVisualBasic 6.0环境下开发标准的Windows直流锅炉水动力调整优化程序 ,并在实际电站直流锅炉上进行应用     

Effectiveness of an energy-consumption information system for residential buildings

The authors have proposed a method of reducing the energy consumption in residential buildings by providing household members with information on energy consumptions in their own houses. An on-line interactive “energy-consumption information system” that displays power consumptions of, at most, 18 different appliances, power and city-gas consumption of the whole house and room temperature, for the purpose of motivating energy-saving activities has been constructed and the effectiveness of the system investigated by installing it in 10 residential buildings. The experiment showed that energy-saving consciousness was raised and energy consumption was in fact reduced by the energy-saving activities of the household members. In this paper, the system is described in detail and the effectiveness of reducing energy-consumption of the whole house and for space heating will be discussed. Also the energy-saving activities in a certain household are shown by using load duration curves.     

节能评估报告中电能消耗的计算方法

根据近几年国家节能评估报告的编制要求,通过工程实例详细介绍了节能评估报告中电气专业电能消耗的计算方法,并提出无功补偿后,采用加权平均算法,重新进行负荷计算,再进行设备年耗电量的计算方法。加权平均算法还可应用于不同产品、不同工段的耗电量的计算。利用不同耗电设备所占比重不同,采用加权平均的算法,使节能评估报告中的计算结果更加科学、准确,更为接近项目的实际电能消耗量。     

动态无功补偿装置(SVC)在精炼炉上的应用

针对天津某钢铁企业精炼炉在运行中对电力系统电能质量的影响,提出了装设动态无功补偿装置(SVC)来改善电能质量的技术方案.根据对称分量法和瞬时无功功率理论推导出了基于瞬时有功、无功电流的SVC补偿导纳实用算法.最后利用仿真软件CHP对该系统进行了仿真,结果表明该SVC装置能够对精炼炉引起的电能质量问题进行有效治理,且补偿...     

节能量计算方法探讨

目前,计算节能量的方法主要有两种:基准单耗对比法和累积和法。国内多采用基准单耗对比法计算节能量。此方法简单、方便,但是在技术措施实施前后产品产量有较大变化时,此方法的计算值存在误差,不能如实监测技术措施的实施效果。与基准单耗对比法相比,累积和法能更真实地计算出企业节能技术措施所带来的节能量,反映出能源消耗的趋势性变化,监测节能技术措施是否、以及具体何时发挥了作用。分析了累积和法在计算节能量时较基准单耗对比法更为真实的原因,并介绍如何使用累积和法监测节能技术措施的实施效果。以某化肥企业为例,结合该企业2009年的能源审计工作,运用累积和法,对该企业的节能量进行计算,分析该企业节能技术措施的实施效果,并发现能源审计期间一些引起企业能耗变化的因素,实例验证了累积和法节能量计算的准确性和有效性。     

Identification of cost-optimal and NZEB refurbishment levels for representative climates and building typologies across Europe

The energy consumptions of the building stock are playing a central role in the energy policy of the European Union. While the Member States are applying the Directives in force, the European Commission is working to update the regulatory framework. Specifically, it is necessary to achieve the great unrealized potential for energy savings in existing buildings. With this aim, the nearly zero-energy building (NZEB) target was introduced, and a comparative methodology framework to calculate cost-optimal levels of minimum energy performance requirements was proposed. This study focuses on the issue of building renovation, and it presents the results obtained with the application of a cost-optimal calculation method for identifying proper retrofit measures to reach cost-optimal levels and NZEB levels. The assessment takes into account an exhaustive set of passive and active renovation options and it was extended to various building types of 60s–70s (residential and non-residential) in a wide range of representative European climatic conditions. A very relevant energy-saving potential was found for all cost-optimal benchmarks, and in many cases, the obtained NZEB refurbishments have resulted interesting also from an economic point of view.     

过网电量和无损户电量线损计算的探讨

供电企业的综合线损率是衡量其节能效果的重要技术经济指标,然而"无损户"和穿越电量的存在往往导致该网综合线损的虚降,使综合线损率失去其可比性。提出一种基于'四分管理'线损数据的可比线损率的计算方法,剔除上述的虚降和虚升,以达到合理评估节能工作的效果。     

Optimization design of BCHP system to maximize to save energy and reduce environmental impact

The energetic and environmental performances of building cooling heating and power (BCHP) system are closely dependent on its design and operation strategy. This paper analyzes the energy consumptions of a conventional separation production (SP) system and a BCHP system respectively and constructs their corresponding environmental impact models. Furthermore, three energy-related environmental issues, global warming, acid precipitation and stratospheric ozone depletion, are assessed in the proposed emission model. To maximize the benefits (energy-saving and emission-reducing) achieved by the BCHP system in comparison to the SP system, genetic algorithm (GA) is employed to optimize the capacity of BCHP system in consideration of its operation mode. A numerical case of BCHP system for a hotel building is applied to ascertain the effectiveness of the optimal method and demonstrate the performances of the optimal BCHP system.     

智能用电楼宇节能综合控制的实现方式

智能用电楼宇是智能电网用电环节的重要组成部分。在上海世博园智能电网综合示范工程中,以国家电网企业馆为建设对象,通过开发楼宇智能用电能量管理系统,采用双向互动技术实现楼宇节能综合控制,展示楼宇节能减排的效果。文章从系统设计角度,阐述了楼宇用电智能化的实现方式。     

工业固定资产投资项目节能评估程序探讨

作者认为节能评估的基础应该是按现行的节能规划、政策、标准、规范、先进工艺技术、先进的节能设备等修改后的可行性研究报告或项目申请报告及其节能专篇,才能真正将节能评估和审查的精神贯穿到项目建设的全过程,真正做到从源头抓节能,从源头规范能源管理,从源头减少能源浪费,为项目建成后的能源高效合理利用及节能管理打下坚实的基础。     

Exergetic performance evaluation of a combined heat and power (CHP) system in Turkey

This study deals with the exergetic performance assessment of a combined heat and power (CHP) system installed in Eskisehir city of Turkey. Quantitative exergy balance for each component and the whole CHP system was considered, while exergy consumptions in the system were determined. The performance characteristics of this CHP system were evaluated using exergy analysis method. The exergetic efficiency of the CHP system was accounted for 38.16% with 49 880 kW as electrical products. The exergy consumption occurred in this system amounted to 80 833.67 kW. The ways of improving the exergy efficiency of this system were also analysed. As a result of these, a simple way of increasing the exergy efficiency of the available CHP system was suggested that the valves‐I–III and the MPSC could be replaced by a 3500 kW‐intermediate pressure steam turbine (IPST). If the IPST is installed to the CHP system (called the modified CHP (MCHP) system), the exergetic efficiency of the MCHP system is calculated to be 40.75% with 53 269.53 kW as electrical products. The exergy consumption is found to be 77 444.14 kW in the MCHP system. Copyright © 2006 John Wiley & Sons, Ltd.