两段式塔式太阳能腔式吸热器设计及性能分析

针对一种新型两段式塔式太阳能热发电的吸热器进行几何设计,建立了呈高斯分布热流密度的条件下吸热器辐射和对流换热以及流动模型,确定了吸热器I和吸热器II受热面蛇形管管道布置方式和几何尺寸,获得了吸热器内部不同位置受热面的热流密度分布情况.结合气液两相传热和流动特点确定了吸热器典型管道内部工质温度、干度、压降和沿管道流程的壁温分布规律.得出两段式塔式太阳能腔式吸热器几何结构的系统化设计流程,并对吸热器进行了热力性能分析.结果表明:两段式塔式太阳能腔式吸热器能够有效减小预热蒸发吸热器的几何尺寸,提高平均辐射热负荷的同时降低吸热器的平均温度,有效提高吸热器的热效率;多管程蛇形管道布置可使出口参数分布更加均匀,避免受热严重不均等安全问题.     

高温熔盐吸热器的传热研究和系统设计

本文对非均匀辐射热流密度太阳能熔盐吸热器传热过程进行了模拟研究,得到了熔盐吸热器内部的温度、传热性能等特征参数。结果表明在轴向和径向上熔盐流体温度和管壁的温度都非常不均匀,同时其综合传热性能要高于按照Sieder-Tate公式的计算值。并对10 MW塔式太阳能热发电的熔盐吸热器进行了设计和分析。     

塔式太阳能水工质吸热器性能分析

上海锅炉厂有限公司自主开发了塔式太阳能热发电吸热器性能设计程序。该程序可同时适应水工质和熔盐工质太阳能吸热器的设计计算要求。针对美国Solar Two工程吸热器,将Boeing North American,Inc.的计算结果和其试验数据与自主开发程序的计算结果进行比较,结果吻合良好。以某个塔式太阳能热发电吸热器为例,对其蒸发段和过热段的设计方案进行了详细的校核计算,重点在吸热器蒸发段的循环流量、干度、鳍端温度和鳍端温差、过热段的管子正面点温度以及吸热器的吸热效率分布等多个方面进行了分析。该校核计算的结果可为后续进行性能评价提供重要的基础数据。     

基于能量流的塔式太阳能热发电吸热器动态建模

塔式太阳能热发电空气吸热器的最大热应力与其温度变化率成正比,吸热器出口空气温度的动态特性影响塔式光热系统的功率特性。结合热电比拟理论,采用对流换热系数和Rosseland辐射传递方程描述传热过程,建立塔式太阳能热发电系统中碳化硅泡沫陶瓷吸热体的能量流模型。通过剖析空气吸热器工作过程的传热特性,得出平均能流密度、吸热体厚度、平均孔径对出口空气温度、吸热体温度的影响,为该类空气吸热器的设计提供了理论依据。     

圆锥螺旋管腔式熔融盐吸热器热性能的数值研究

提出一个用于塔式太阳能发电系统的圆锥螺旋管式熔融盐吸热器,对其热性能进行数值研究,得到吸热器的热损失以及热效率,并将数值计算结果与美国圣地亚实验室的熔融盐子系统的实验数据进行对比。研究发现:在相同的阳光入射条件和风速条件及接近的开口尺寸和管道长度下,采用圆锥形螺旋管吸热器管道外壁面平均温度降低、吸热器效率提高。     

基于XGB算法及全天空成像仪图像的超短期DNI预测

吸热器是塔式太阳能热发电站的核心设备,但云层短时间的遮挡和离开会使吸热器接收的太阳直接辐射(DNI)发生随机波动,造成吸热器表面受热发生剧烈变化,会影响塔式太阳能热发电站的安全运行.本文提出了一种基于极值梯度提升(eXtreme Gradient Boosting,XGB)算法及全天空成像仪图像的超短期DNI预测方法....     

塔式太阳能热发电站吸热器指向点动态调度和优化设计

针对塔式太阳能热发电站中的核心设备吸热器,提出一种基于遗传算法的指向点设计与优化控制策略,该策略通过将塔式太阳能热发电站指向点动态调度问题转换为遗传算法寻优问题,建模求解得到的结果在保证吸热器正常使用寿命的前提下,优化了吸热器面板上的能量分布的均匀性,在保证吸热器材料能流密度要求的情况下,有效提高了截断效率。提出以截断效率和吸热器效率整体作为优化目标的吸热器参数设计方法,将该方法成功应用到某50 MW塔式熔盐电站的吸热器参数设计中,得出该熔盐吸热器最优尺寸为:吸热器受光面积580 m~2,吸热器高16.78 m,直径11 m。所得最优尺寸参数在相同的吸热器受光面积下,综合效率可提升1.78%;在相同的直径条件下,综合效率可提升2.15%。     

塔式太阳能热发电技术的发展

塔式太阳能热发电系统具有聚光比大、投射到塔顶吸热器上的平均热流密度高、工作温度高、电站规模大和年度发电效率高等特点,提高效率和降低成本的潜力较大。文章阐述了塔式太阳能热发电技术的工作原理和系统组成;介绍和分析了国内外已建成的塔式太阳能电站;指出了塔式太阳能热发电技术的发展现状、技术难点和未来发展方向;探讨了我国规模化发展塔式太阳能热发电技术须解决的问题。     

聚光太阳能热发电中吸热器吸收涂层的选择

对各类聚光比的聚光太阳能热发电中的吸热器吸收涂层进行了研究,同时对耐高温太阳吸收涂层进行了高温热处理和辐射性能测试.研究表明,菲涅耳线式和抛物面槽式聚光吸热器由于聚光比较小,吸热体表面温度较低,主要采用选择性涂层以提高吸热表面温度和吸热效率;而塔式和抛物面碟式聚光吸热器由于聚光比大,吸热体表面温度较高,高温时的吸收涂层在红外波段的吸收率下降,因此主要采用高吸收率的耐高温涂料为太阳吸收涂层.     

一种多孔介质太阳能吸热器传热研究

为了研究塔式太阳能多孔介质吸热器的传热传质特性,建立吸热器稳态传热模型,选择适合多孔介质太阳能吸热器的体积对流换热系数模型,采用数值方法求解,并分别分析孔隙密度、孔隙率和入口空气速度对温度场的影响。文中技术可以为同类型太阳能吸热器的设计和改造提供参考。     

阳光帆船

扬起帆的船，在风的推动下，可以在浩瀚的海洋里航行；是否能有一种“阳光帆船”，利用太阳光的推动，也可以在宇宙间航行呢？日本太空科学研究所的科学家回答：可以。原来，光除了具备波性质，也拥有粒子性质，光的粒子(光子)碰撞到阳     

Solar Chimneys

The design and construction of the solar chimney pilot plant in Manzanares, and the investigations described below, were commissioned by the Minister of Research and Technology of the Federal Republic of Germany. The work was supervised by the energy research project management department of Kernforschungsanlage Jülich GmbH (The Jülich Nuclear Research Establishment).

The present paper communicates preliminary test results from the solar chimney pilot plant described in (1). This, the first solar chimney power plant in the world, was commissioned on 7 June 1982 and has been in continuous operation since then. Individual energy balances, collector efficiency values, pressure losses due to friction and losses in the turbine section are discussed with reference to 24-hour records. The findings agree well with results obtained hitherto in model calculations.     

Solar possibilities

A major energy transition of some kind is inevitable. For rich lands and poor alike, the energy patterns of the past are not prologue to the future. The oil-based societies of the industrial world cannot be sustained and cannot be replicated. The huge increases in oil prices since 1973 virtually guarantee that the Third World will never derive most of its energy from petroleum. Gross world oil production is likely to peak within the next decade; per capita world oil production may have already peaked. The world thus faces an awesome discontinuity in the production and use of energy.In the past, such energy transformations invariably produced far-reaching social change. The 18th-century substitution of coal for wood and wind in Europe, for example, accelerated and refashioned the industrial revolution. Later, the shift to petroleum altered the nature of travel, shrinking the planet and reshaping its cities. The coming energy transition can be counted upon to fundamentally alter tomorrow's world. This will be as true of a solar era as of a nuclear age.Sunlight is abundant, dependable, and free. With some minor fluctuations, the sun has been bestowing its bounty on the earth for more than four billion years, and it is expected to continue to do so for several billion more.     

太阳能之歌

“万物生长靠太阳”。人类虔诚地崇拜太阳，热情地歌颂太阳。 太阳不断放射出光和热。太阳内部发生着核反应，温度高达1．5×10^7℃，辐射出大量的热能。传到地球外大气层的太阳辐射能量相当于人类1年消耗的全部商品能量的28000倍，其中47％穿过大气层到达地球表面。     

Solar hydrogen

The intermittance and the geographical distribution of solar energy require means of storing and transporting it to the user's place. An ideal means of doing this is to split water in order to obtain hydrogen.Hydrogen is a carbon-free fuel which oxidizes to water as combustion product. The generated water becomes, together with renewable primary energy for splitting it, a source of clean and abundant energy in a carbon-free, natural cycle.Hydrogen is a fuel which can be transported over long distances and stored so that solar energy can be transported from energy rich countries over long distances in ships to Europe, stored underground or in containers and used in gaseous or liquid form in industry, households, power stations, motor cars and aviation.Solar energy as primary energy is discussed. A special form of it, the cheapest and by now largely available hydropower, is stressed.Techniques of hydrogen production, vectorisation and end use are discussed as well as safety aspects, costs and strategy for its implementation.     

Solar ponds

This report provides the background to, and the current status of, solar ponds as proven viable large-area collectors capable of providing both low-cost thermal energy and mechanical or electrical energy using state-of-the-art low-temperature turbo-generators.After a short background statement giving the history and motivation to create a viable large-area collector with built-in storage, the basic theory of salt-gradient solar ponds is sketched. (More detailed-theory is available from the given references, particularly two recently published handbooks.) NaCl and MgCl₂ are two common and low-cost salts suitable for solar ponds. A number of problems such as the adverse effect of wind, leakage, fouling—and their solutions—are indicated as are some fundamental constraints (Section 8) that limit the sites suitable for solar ponds. Practical details include how ponds are built and filled and how the heat is extracted. Section 7 presents a condensed account of solar pond experience in a number of countries.Practical operating temperatures of 90°C are obtained with collection efficiencies usually between 15 and 25 per cent: this permits a number of practical applications as discused in Section 10, i.e. heating and cooling, power production and desalination.Realistic pond cost figures indicate thermal energy costs equivalent to US$41 per ton of fuel for a sunny climate (using a conservative 11.7 per cent annual charage on capital): such low-cost calories permit thermodynamic conversion to power: although the conversion efficiency is low, the solar pond power station (SPPS) is viable in many cases. Bus-bar power costs, for a sunny climate, vary from a high of US13.5 cents/kWh—using present technology—to a low 5.3 cents in sizes of 20 GWhr(e) per annum or larger.A 150-kW SPPS has already been built and successfully operated in Israel since December 1979 and a 5000-kW unit is due for completion in the next 2 yr.The ability of a solar pond to store heat even from summer to winter greatly increases its usefulness in almost all applications: for power production, the SPPS can—like a hydro-electric plant, provide peaks of power, on demand—far in excess of the pond mean capacity. The estimate that SPPS costs flatten out at 20–40 MW is of interest to developing countries that could install generating capacity in relatively small steps as demand grows.