Study on performance of a packed bed latent heat thermal energy storage unit integrated with solar water heating system

INTRODUCTION Efforts of rational and effective energy man-agement, as well as environmental considerations, increase the interest in using renewable energy sources, especially solar energy. Because of discrep-ancy between the energy supply and demand in solar heating applications, a thermal energy storage (TES) device has to be used for the most effective utilization of the energy source. Energy storage combined with solar collectors and photovoltaic systems have been developed over the…     

Regulation law of turbine and generator in organic Rankine cycle power generation experimental system

In the performance experiment of organic Rankine cycle power generation experimental system, the loadresistance-regulation method is one of the most important regulation methods. However, the regulation law has not been clear enough to guide the experiment, which is unfavorable to the experimental research on organic Rankine cycle. In this paper the regulation law of turbine and generator by the load-resistance-regulation method is studied theo- retically and experimentally. The results show that when the thermal cycle parameters keep constant, the turbine speed increases with the increase of load resistance and there is a maximum value of transmission-generator efficiency with the variation of the turbine speed; when the turbine speed and generator speed keep constant, the transmissiongenerator efficiency decreases and gradually tends to zero with the increase of load resistance.     

Parametric optimization of organic Rankine cycle with R245fa/R601a as working fluid

In order to select the appropriate working fluids and optimize parameters for medium-temperature geothermally-powered organic Rankine cycle(ORC), R245 fa is mixed with R601 a at geothermal water temperature of 110 ℃. Based on thermodynamics, the characteristics of mixture and its influence on the performance of ORC under different evaporating temperatures and composition proportions are analyzed. Results show that the zeotropic mixture R245fa/R601a(0.4/0.6) has the highest performance. When the evaporating temperature reaches 67 ℃, the outlet temperature of geothermal water is 61 ℃, the net power output is the highest and the thermal efficiency is about 9%.     

新型（硬聚氯乙烯）低温地板采暖实验及理论分析

低温地板采暖系统与传统的采暖系统一样,从舒适性角度出发,地板表面温度有标准的温度范围,为了研究该新型采暖地板的热工性能,总结实际运行中的规律,该文通过实验及理论分析研究相结合的方法,得出了维持室温为18、20、22℃工况下地板表面及室内空气的温度分布,总结出地板的散热量与地板表面温度与室温温差之间的关系,以及地板的散热量与供回水温度和室温温差之间的关系.     

钢桥面硬沥青浇注式沥青混合料低温性能研究

通过汉堡轮辙试验 ,考察了浇注式沥青混合料的抗车辙能力 ,硬沥青浇注式沥青混合料具有良好的抗车辙能力 .通过低温弯曲试验和逐步降温的钢桥面铺装复合结构疲劳试验 ,测试与比较了使用硬沥青的浇注式混合料低温抗裂性能 .高性能聚合物改性沥青浇注式混合料具有较长的疲劳寿命和较低的断裂温度 ,可用于钢桥面浇注式沥青铺装 .     

一种新型辐射吊顶采暖系统的实验研究与节能分析(英文)

为研究毛细管-金属板吊顶的采暖特性和节能潜力,构建了毛细管-金属板辐射吊顶采暖系统,实验分析了系统的实际采暖性能和热舒适性,从地源热泵的COP和末端设备的效率探讨了系统的节能潜力.结果表明,该采暖系统具有良好的热稳定性和热舒适性.当系统达到稳定状态时,辐射传热占总传热量的62.7%,并且总传热量可以满足大多数建筑的采暖需求.与地板辐射供暖系统相比,毛细管-金属板辐射吊顶采暖系统具有预热时间短、供水温度低和采暖能力强的优势.当供水温度为28~33℃时,地源热泵的COP显著提高.当基准温度为5℃时,毛细管金属板辐射吊顶的效率是辐射地板的1.6倍.该新型辐射采暖系统显示出较大的节能潜力.     

低待机功耗开关电源跨周期模式集成控制电路的仿真实现

This paper explores and proposes a design solution of an integrated skip cycle mode (SCM) control circuit with a simple structure. The design is simulated and implemented with XD10H-1.0μm modular DIMOS 650 V process. In order to meet the requirement of a wide temperature range and high yields of products, the schematic extracted from the layout is simulated with five process corners at 27℃and 90℃. Simulation results demonstrate that the proposed integrated circuit is immune to noise and achieves skipping cycle control when switching mode power supply (SMPS) works with low load or without load.     

Evaluation of a teacher's classroom performance using the Florida performance measurement system

This article documents the use of the screening and formative observation instruments of the Florida Performance Measurement System; a system whose content validity, reliability, and predictive validity has been established for use in evaluating beginning, certified, and master teachers. A videotaped lesson, taught by the Secretary of Education, William Bennett, was coded and the data analyzed by reference to the norms of high school teacher performance in Florida. The specific strengths and areas of potential improvement of the teacher's performance are identified and constructive changes in performance suggested.     

Improved thermal performance of a hydronic radiant panel heating system by the optimization of tube shapes

The thermal performance enhancement of the hydronic radiant floor heating system by tube shape refinements is investigated in this paper. Both analytical and detailed numerical modelings are carried out to predict the performance of the radiant system. While the simple analytical model briefly investigates the possibility of the effect of the tube shape improvement with the parametric analysis, the commercial computational fluid dynamics (CFD) code (Ansys/CFX) is used to perform the detailed 3D analysis under different tube shape conditions. The fin thickness, the number of fins, and the tube thermal conductivity turn out to have significant effects on the radiant system performance. The potential energy saving impacts of the tube shape refinements are also discussed. The tube shape improvement turns out to increase the floor surface temperature and to decrease the hot water temperature drop across the system, resulting in heating energy savings.     

融合DEA的高校二级学院仪器设备管理绩效评价体系构建研究

仪器设备作为高校资产重要组成部分,目前管理绩效评价体系尚不完善,投入产出比例有待考证。该文按照科学合理、系统导向性原则,运用DEA技术对Y校31个二级学院的仪器设备的投入产出进行研究,分析评价Y校各学院仪器设备管理的相对效率,构建适合高校二级学院仪器设备考核的绩效评价体系。     

基于SQUID系统低温强磁环境建立电学测试平台

为了扩展美国量子设计公司制造的超导量子干涉仪(SQUID)的测试功能,针对SQUID低温强场的测试环境,使用自制的低成本的电学测试插杆连接电学测试仪,通过LabVIEW软件编程,建立可进行电阻率、V-I曲线、铁电等低温电学性质测试的平台。该平台节约了高昂的仪器购置费用,扩展了SQUID的功能,使其为低温材料(如超导)的研究发挥非常大的作用。     

系统视角下的中原经济区发展趋势预测与分析

随着中原经济区规划受到普遍重视,为把握区域发展中存在的利弊因素需要从系统工程的角度对河南省下一阶段发展趋势进行研究.首先应当看到经济发展受多方面因素影响和制约,需要将多方面影响经济协调发展的因素纳入衡量体系;其次在经济持续增长的背景下应当警惕其中存在的不稳定因素;为此小样本预测方法引入的区域经济预测分析中具有必要性.通过系统论角度的建模分析得到了河南省＂十二五＂期间经济系统全方面的预测,结果表明河南省经济在未来＂十二五＂期间将保持稳定快速发展,同时面临的投资泡沫等压力也随之上升.     

A comparison of learning management systems in a school district: searching for the ideal personalized integrated educational system (PIES)

This study explored the use of several learning management systems (LMS), their benefits, and their limitations in relation to the desired characteristics of an ideal Personalized Integrated Educational System (PIES) for the information age. A qualitative research design was used. The participants of the study were teachers, administrators, and technology coordinators in a small suburban school district. The data were collected through interviews and were subjected to content analysis. The findings of the study indicated that each of the LMSs investigated in this study still has some significant limitations, for none of them provides all the information-age functions of PIES, and what an ideal PIES should possess as information-age functions can be categorized under students’ learning, assessment and system-related preferences.     

地源热泵-辐射供冷/暖复合空调系统的热舒适度评价和能耗分析(英文)

提出了一种新型的地源热泵-辐射供冷/暖复合空调系统,分析了该系统的原理和特点.该系统被应用于镇江西津渡展览馆中,并利用TRNSYS软件对其热舒适度和能耗进行了模拟分析.结果表明,地源热泵-辐射供冷暖复合空调系统在冬季采暖运行时,地板辐射和顶板辐射方式均具有良好的热舒适度,且无须采用机械通风;在夏季空调运行时,地板辐射和顶板辐射必须配合合理的机械通风,才能具有良好的热舒适度;在同样的热舒适度条件下,顶板辐射供冷/暖的全年能耗比地板辐射低.     

机械传动系统中优化齿轮减速传动比的分析

为了减少机械伺服系统中机械传动的能耗,提出并分析了通过优化传动系统中齿轮减速传动比来减少能耗的方法,并与传统的惯量匹配法进行比较。结果表明,应用优化齿轮减速比方法可以比惯量匹配法大大减少了能耗。     

太阳能二次聚集器聚光性能研究

采用蒙特卡洛射线踪迹法,ProE和TracePro软件技术,模拟分析了多棱台与一次抛物面、复合抛物面二次聚集器与一次抛物面两级聚集器的太阳光聚集传输特性。通过对比,发现多棱台二次聚集器的几何聚光比为1.4左右(约为复合抛物面聚集器的70%)。多棱台与一次抛物面、复合抛物面二次聚集器与一次抛物面两级聚集器圆筒侧壁和底面的太阳能流密度分布图像相当(沿圆周方向,复合抛物面两级聚集器相对比较平滑)。结论为反射二次聚集器技术发展提供理论依据。     

高温材料实验室节能降耗的探索研究

对高温材料实验室在高等院校学生专业培养及实验室组成及能源消耗特点进行阐述.探索了适合高温材料实验室节能降耗的新模式,提出了采用新型低水泥结合氧化铝空心球预制块对高温电炉的炉顶、炉壁进行全封闭改造、采用减少原材料使用的实验方法以及固体废弃材料回收利用的节能降耗具体方法.     

基于ZigBee技术的矿井安全综合监测系统设计

对煤矿矿井的安全监测技术进行了系统性的分析与研究,提出了一种基于ZigBee无线网络技术的具备环境检测、设备监控与人/车定位功能的矿井综合安全监测系统的总体结构.根据系统结构对监测系统中的核心设备监测分站的功能需求进行了技术分析,完成了包含CAN总线接口、ZigBee协调器以及设备监控等单元电路的新型监测分站的软硬件设计.通过在实验室组建一个矿井安全监测模拟环境,验证了系统架构的可行性和分站设备的主要功能.     

南阳市旧城片区自行车系统规划构想

分析了自行车交通的特征与优势，结合南阳交通情况，探讨了建立自行车专用道路系统、改善自行车停车条件等策略，旨在为南阳市的绿色交通发展提供新的思路。     

基于1-9标度法的交互性资产绩效管理评价体系

通过对交互性资产特点的分析,将安全性、效用、效益和满意度作为交互性资产绩效管理评价的一级指标,并在一级指标下面甄选二级指标,采用1-9标度法,分别对一、二级指标构建比较判断矩阵,得出每个指标的权重值,并进行一致性检验,满足一致性要求。