Results of the development of a solar accumulation-type water heater made of polymer and composite materials

Results of the development and preliminary tests of a solar water heater completely made of polymer and composite materials are presented. The combination of a solar collector and storage tank into a united construction in combination with the application of modern fabrication technologies of bulk units made of polymer materials makes it possible to considerably decrease the expenses per area unit of the receiving surface of the heater with maintaining high-energy conversion characteristics of the solar energy into low-potential heat. This increases the competitiveness of such installations in comparison with conventional solar water heaters with separate solar collectors and a storage tank.     

用于消纳风电的城区用户电热水器负荷群滑模控制策略研究

居民电热水器是一种典型的热储能负荷,用电产生的热水具有热存储性,可以消纳波动性风电。提出了用于消纳风电的电热水器负荷群滑模控制策略,来实时控制电热水器负荷群。控制率与电热水器群数量、热水使用情况等相关,对于消纳风电具有较强的鲁棒性。采用某城区居民区电热水器负荷群的仿真研究表明,提出的电热水器群滑模控制策略能有效消纳风电,验证了电热水器负荷群滑模控制策略有效性。     

1000MW超超临界压力机组单列高加解列后的分析

对潮州电厂1 000 MW超超临界压力机组在协调方式下单侧高加解列后的参数进行了分析,指出了在高负荷单列高加解列后的处理要点;并且指出了单列高加解列后的危险点,针对这些危险点有针对的进行了分析,在出现高负荷单列高加解列后,做出提前的干预,以防事故扩大化;     

煤炭-太阳能联合作用下锅炉水动力特性的研究

为了研究太阳能引入对燃煤电站机组运行特性的影响,对1台亚临界300 MW机组自然循环锅炉进行了40个工况下的锅炉水冷壁水动力计算,分析了不同负荷下太阳能热引入对锅炉水动力特性的影响规律。计算与分析结果表明,太阳能热引入对水冷壁起沸点高度和汽包欠焓有显著影响;在60%～70%额定负荷不宜引入太阳能热,在高负荷与高压加热器切除低负荷时则可引入太阳能热。得出:太阳能的引入不会导致水冷壁上部换热特性发生变化,但会使汽包欠焓减少等结论。     

电站高压加热器最佳更换周期的研究

高压加热器作为电站的一种主要辅助设备,其运行直接影响机组的出力。高压加热器设备最佳更新周期的研究是以其经济寿命为研究前提,以提高其工作效率,降低其维修成本,使机组安全、可靠、经济地运行为目的,来确定其科学合理的使用年限。文中根据高压加热器的可靠性特点,在分析高压加热器运行规律和故障特征的基础上,利用技术经济学中的年均总费用最小法,通过充分考虑电站高加停运造成的经济损失的前提下,建立高压加热器的最佳更新周期动态数学模型。利用模型对某厂2号机组高压加热器进行了计算和分析,得出其科学合理的使用寿命。模型为电力企业科学及时地更换高压加热器,减少企业不必要的经济损失提供了理论依据,可供发电企业管理者和检修技术人员参考。     

7号低压加热器正常疏水不畅原因与对策

300MW引进型机组7号低压加热器正常疏水不畅是一个共性问题,主要原因是7、8号低压加热器的汽侧压力之差较小,疏水水位差较大,疏水管系阻力大.在彭城电厂300MW机组工程设计中,对一期工程调整了加热器疏水接口位置,减小了疏水水位差;二期工程用旋转式可调球阀代替阀芯升降式直通型疏水调节阀,并取消2侧的检修隔离阀,减少了疏水管道的阻力,机组在大负荷范围内运行时,7号低压加热器能正常疏水.     

直膨式太阳能热泵热水器实验研究及经济性分析

直膨式太阳能热泵热水器(DX-SAHPWH)的运行经济性除与系统本身的结构和性能相关之外,还与多种因素有关。建立了直膨式太阳能热泵热水器样机的集总参数法模型,并在上海的气候条件下进行了实验验证。根据全国典型气候地区的气象参数模拟系统运行的耗能情况;用综合能源价格法分析了影响系统经济性的关键因素,并将样机与几种传统热水器的全年运行情况进行了比较。分析表明,气候条件、能源价格对比以及运行控制策略是影响系统运行节能性和经济性的主要因素。     

基于预切换状态的电热水器负荷群调控策略

风电消纳问题已成为我国风电进一步发展的瓶颈,以需求侧资源逆向匹配生产端的风电能源,是促进风电消纳的有效途径。本文以家用电热水器为研究对象,提出了一种新的需求响应调控策略:首先建立电热水器的热力学模型和动态调控模型;将电热水器在自然运行状态下1min之内将要开启或关闭的状态定义为预切换状态(pre-switching state,PSST);采取考虑PSST的分群策略,并基于T_se和C_se联合指标分别对开启群和关闭群中的电热水器进行优先级排序,生成负荷群优先序列;最后建立负荷群功率调整量优化模型。将调控策略应用于风电消纳场景并与其它策略进行对比,仿真结果表明,基于PSST的负荷群调控策略能够较好地跟踪风电响应目标,在有效减小响应误差的同时,能够均衡负荷群加热效果,具有良好的应用前景。     

Some perspective decisions for the regeneration system equipment of the thermal and nuclear power plants decreasing the probability of water ingress into the turbine and rotor acceleration by return steam flow

The regeneration system heaters are one of the sources of possible ingress of the water into the turbine. The water penetrates into the turbine either at the heaters overflow or with the return flow of steam generated when the water being in the heater boils up in the dynamic operation modes or at deenergization of the power-generating unit. The return flow of steam and water is dangerous to the turbine blades and can result in the rotor acceleration. The known protective devices used to prevent the overflow of the low-pressure and high-pressure heaters (LPH and HPH), of the horizontal and vertical heaters of heating-system water (HWH and VWH), as well as of the deaerators and low-pressure mixing heaters (LPMH) were considered. The main protective methods of the steam and water return flows supplied by the heaters in dynamic operation modes or at deenergization of the power-generating unit are described. Previous operating experience shows that the available protections do not fully prevent water ingress into the turbine and the rotor acceleration and, therefore, the development of measures to decrease the possibility of ingress of the water into the turbine is an actual problem. The measures allowing eliminating or reducing the water mass in the heaters are expounded; some of them were designed by the specialists of OAO Polzunov Scientific and Development Association on Research and Design of Power Equipment (NPO CKTI) and are efficiently introduced at heat power plants and nuclear power plants. The suggested technical solutions allow reducing the possibility of the water ingress into the turbine and rotor acceleration by return steam flow in the dynamic operation modes or in the case of power generating unit deenergization. Some of these solutions have been tested in experimental–industrial exploitation and can be used in industry.     

660MW超临界机组加热器运行热经济性影响因素的定量分析

加热器上端差和抽汽压损是影响加热器运行性能的两种主要因素。在多元扰动下热力系统能效分析模型基础上,以660MW超临界机组的典型工况为例,计算了这两种主要因素对机组能效影响的强度系数,并绘制了强度系数关于机组运行负荷的比较图和趋势图,找出了该机组实际运行中应密切监视和重点控制的参数,为机组的节能降耗提供帮助,也可为其他类型机组的同类问题提供参考。     

压水堆核电机组加热器散热损失对机组经济性的影响

针对压水堆核电机组回热和再热系统各级加热器存在散热损失的问题,笔者根据热平衡法和（火用）分析方法,从定量计算的角度阐述了回热和再热系统各级加热器散热损失对机组经济性的影响,建立了压水堆核电机组热力系统在定流量情况下全面的汽水分布矩阵和（火用）计算模型,并在此基础上,计算了由各级加热器热损造成的机组相关参数变化量.计算结果表明,相对其他加热器,高压加热器的散热损失对机组的经济性影响较大.所以,机组运行中应尽量减少高压加热器的散热损失.     

高加解列对300MW循环流化床机组的影响分析

因为排烟温度偏高,威胁布袋除尘器的安全,某热电厂在大规模技改之前,夏季高负荷工况下只能切除一级或多级高压回热加热器来降低烟气温度。为了研究切除高加对机组热力性能的影响规律并给出指导建议,首先开展了实际运行机组的高加投退实验,然后利用锅炉/汽轮机运行数据对运行工况下退出高加的方案进行了理论计算与分析,结果表明:退出高加后,给水温度迅速降低,排烟温度随之降低,保护了除尘器安全;每退出一级高加,给水出口温度降低约30~40℃,排烟温度则降低10~15℃;然而从机组的经济性角度看,虽然退出高加后锅炉热效率略有上升,然而机组总体热效率大幅下降,供电煤耗上升2~8 g/kW·h,按年切除高加运行1 000 h估算,年燃料费用将上升34~100万元。     

1000MW超超临界机组回热系统加热器运行经济性分析

根据1000MW超超临界机组高、低压加热器运行的各项技术经济指标,定量分析有关指标对机组经济性的影响,并且对高、低压加热器运行经济性进行了分析和评估,同时提出了高、低压加热器水位调整的的试验准备、试验方法、热控定值修改等技术措施和建议,供设计、运行维护单位参考。     

引射式加热器应用于200MW机组低压回热系统热经济性分析

200 MW火电机组低压回热系统存在较大的火用损失,严重降低机组的热经济性和效率。应用等效焓降法,深入分析采用引射式加热器应用于机组低压回热系统时,机组热经济性变化的因素。在此基础上,对N200-130/535/535型机组低压回热系统的四级面式低压加热器进行局部替代,以比较分析各种替代方式对机组热经济性变化的影响情况。计算结果表明:替代全部四级面式低压加热器是最优化的替代方式,可使系统的热经济性提高0.296%。     

高压加热器碳钢换热管及管板的冲蚀和腐蚀

我国火电机组的高压加热器常使用碳钢管作为换热管,由于碳钢的抗冲蚀和耐腐蚀性能较差,因此,高压加热器换热管的爆管及管板被冲蚀情况屡有发生。不同的工况与水质都会加剧对换热管的冲蚀和对管板的腐蚀,对这些情况进行具体分析,提出解决措施,控制被冲蚀和被腐蚀速度,才能使高压加热器的使用寿命达到设计值。     

Self-Regulating PTC Heating Systems: A New Approach for Electric Heating Appliances

Self-regulating ceramic heating systems that operate without conventional thermostatic controls are now being designed into heated appliances. The result is longer life, lower cost, and more streamlined appliance packaging. The development appropriately comes at a time when end of life safety is receiving increased attention, cost reductions in heater-thermostat systems are producing diminishing returns, and the volume of heated portable appliances for personal care and food warming is growing rapidly. The Semiconducting barium titanate heaters undergo a crystalline phase change and resultant resistivity increase in the vicinity of the ferro-electric curie temperature. This characteristic provides high initial power at which point the sharply increasing heater resistance reduces power to the required steady-state level. Positive temperature coefficient (PTC) barium titanate has been used since the 1950's for low voltage sensors, but was only made available for appliance heaters by the recent development of line voltage materials for a different segment of industry?color television. One third of all color sets now use 120-V PTC degaussing elements. The paper discusses the complex thermal design considerations involved in the development of a PTC heater for 10-200 W appliances and reviews the application of a PTC heater to a food warmer.     

高压加热器泄漏原因分析及改进措施

经统计,加热器尤其是高压加热器(高加)故障仅次于锅炉爆管,为发电厂设备故障的第二位。在加热器各种故障统计中,管系泄漏所占比重最大。以徐州发电厂机组为例,对高加种种泄漏现象进行分析,寻找其产生的原因,提出保证高加安全运行的预防措施。     

基于无量纲的电站加热器变工况建模和研究

回热系统是发电机组热力系统重要组成部分,加热器是其主要的辅助设备。传统回热系统加热器变工况运行的数学模型非常复杂,建模过程中涉及流体相变问题。本文基于电站加热器在实际运行中的数据,采用无量纲方法建立加热器运行模型,无需考虑加热器内部复杂的传热过程。将模型用于某660 MW超超临界汽轮机组的低压加热器上,结果表明:利用该模型计算的加热器出口水温和实际测量数据偏差很小;在满足精度要求的情况下,该模型简单方便,工程上可用于回热系统加热器的经济运行指导和故障诊断。     

Mechanical characteristics of line post type polymer insulation arm for 154 kV

This paper describes the mechanical characteristics of a 154 kV line post type polymer insulation arm that functions both as the steel arm and as the porcelain insulator of the currently used steel transmission towers. The 154 kV line post‐type polymer insulation arm consists of polymer composite insulators, called units, that include two horizontal units with an open angle, to respond to a longitudinal load of 40 kN, and a suspension unit to respond to a vertical load. Its installation length is about 2.3 m. Samples of the insulation arm were installed at different places on an electric wire to form a truss structure and a frame structure, in order to examine their mechanical characteristics. For the truss structure, neither remarkable bending stress nor torsional stress was observed in the FRP core. The mechanical force design of the insulation arm can be evaluated in reference to the axial force of the FRP core only. The buckling coefficient, for evaluating the axial force of the insulation arm with the truss structure, was experimentally identified. Moreover, we were able to show that a static load test, for evaluating the mechanical force performance of the insulation arm against a longitudinal load, is more severe than an impact load test at the same longitudinal load. ©1998 Scripta Technica, Electr Eng Jpn, 126(2): 23–30, 1999     

旋转暖风器的应用

针对固定式暖风器存在的风阻大、送风机和一次风机电耗高、暖风器出口风温达不到设计要求、暖风器及疏水系统振动严重等问题,提出采用旋转暖风器的解决方案。实践证明:和固定式暖风器相比,这种旋转暖风器彻底解决了原暖风器存在的问题,且设备可靠性好,节能效果明显。