槽式太阳能光热系统发电量计算研究

针对太阳能槽式光热发电系统,基于光学、力学、传热学、材料学等多方面理论知识,从太阳能光照资源出发,综合考虑集热系统、换热系统、储热系统以及常规发电系统各环节效率及折减因素,研究建立了一套太阳能槽式发电量计算模型,为光热发电项目前期咨询及后期运行预测数据提供参考。     

太阳能光热发电技术发展现状

介绍太阳能光热发电技术系统：塔式、槽式和碟式3种太阳能光热发电系统,对各类太阳能光热发电技术与常规发电技术进行分析对比,阐述3种太阳能光热发电技术的发展现状及其存在的问题,说明太阳能光热发电具有的广阔应用前景。     

太阳能雾化闪蒸DSG热发电的试验研究

一引言在槽式太阳能热发电系统中,采用DSG(direct steam generation)即直接蒸汽发电技术,可替代昂贵的传热流体导热油,显著降低制造成本,提高光热转换效率,但压力波动等技术障碍阻碍了DSG技术的应用。至今在太阳能热发电领域,还没有采用DSG技术的抛物槽式电站。目前,太阳能热发电期待突破的科技前沿主要是降低成本、替代合成导热油和热交换器、提高热力学效率三项课题。一些科研人员正以DSG技术为突破口,提高太阳能热发电的竞争力,从而实现太阳能热发     

太阳能光热与热电耦合发电技术综述(上)

正1太阳能光热发电技术概述太阳能光热发电即聚光太阳能热发电(Concentrating Solar Power),也称CSP,是太阳能发电中不同于光伏发电的另一种技术。光热发电技术是利用光聚焦原理,把太阳光线的分散能量进行高度聚集,通过吸热器中工质吸收阳光热能,直接或间接地加热水,产生一定参数的蒸汽,然后送往汽轮发电机组进行发电。实际应用的主要技术种类有槽式、塔式、碟式和线性菲涅尔式。1.1槽式光热发电技术分别采用槽式聚光镜和吸热管来聚焦和吸收太阳光热能,进而转化成电能。槽式聚光镜是一种高精密度的太阳反射镜,按主要制造材料可分为两种:玻璃反射镜和铝板反射镜,反射镜的横     

太阳能热利用系统能势匹配程度的对比分析

基于太阳能热利用系统,建立能势分析模型,对太阳能聚光过程、光热发电、光热化学等主要环节进行能量分析和能势分析,并对光热发电、光热化学2种技术路线进行对比。结果表明太阳能与吸热工质能势不匹配是太阳能热利用系统效率的关键限制因素,热功转化、热化学过程的不可逆性相对较小。现有太阳能光热、光热化学热利用系统的效率均较低,有较大的提升潜力。     

槽式集热系统热膨胀分析及补偿措施

在槽式太阳能光热电站中,集热系统负责收集太阳辐射热量,通过反射镜聚焦,加热集热管内导热介质,使加热后的导热介质进入到蒸汽发生系统、储热系统工作。集热系统是整个槽式太阳能光热电站的重要系统之一,集热效率对发电效率有着至关重要的影响。文中通过对影响槽式集热系统的热膨胀进行分析计算,并提出补偿措施,提高集热器的集热效率。     

太阳能与燃煤机组混合发电系统的热经济性分析

以某型300 MW机组为例,利用抛物面槽式集热器收集太阳能热量,提出7种太阳能与燃煤机组集成方案,并定义太阳能加热给水与燃煤机组混合发电系统的循环效率、太阳能热电转换率等评价指标,应用变热量等效焓降法计算理论,对原机组及不同集成方案进行热经济性能分析。结果表明:太阳能与回热系统混合发电,既能增加发电量,提高太阳能热电效率,又能降低纯太阳能发电投资成本,其代价是混合发电系统的热效率将下降;给出的所有集成方案中,取代1段抽汽方案产生的额外电能和太阳能热电转换率最大,标煤耗率和热耗率最小,为最佳混合方案。     

槽式太阳能热发电技术发展现状与趋势

在简述太阳能热发电优势的基础上,着重阐述了槽式太阳能热发电技术的聚光镜、集热管、跟踪技术、工作介质、技术路线与方案最优化研究的要点、技术现状和发展趋势。最后对近几年建成的典型电站技术特点、太阳能光热利用途径和槽式太阳能热发电成本趋势进行了介绍。     

太阳能光热发电中导热油循环系统的设计开发

基于槽式光热、塔式光热和碟式光热发电站的常用类型,分析光热发电中使用的化学合成型导热油的种类、物理特性和技术参数,设计开发槽式太阳能光热发电站中导热油循环系统的工艺流程。为解决因季节、昼夜和云雾、雨雪等气象条件的影响而造成太阳能供应不足的情况,设计开发了白天以槽式太阳能光热发电为主、夜晚采用燃生物质燃料或燃天然气导热油炉供热发电为辅的联合运行发电站的混合发电模式。提出了导热油循环回路系统中注油和排油的方法,研究了槽式抛物面管状集热器内导热油的最高油膜温度计算方法。     

太阳能光热与火力发电耦合互补特性分析与研究

太阳能光热与火力发电耦合互补是指以温度对口、能源阶梯利用为原则,将太阳能光热发电与常规火力发电厂的热力系统通过不同方式进行耦合互补,在机组发电量不变的前提下,采用太阳能光热系统替代部分燃煤消耗,降低耗煤量。本文结合工程实例,提出了3种太阳能光热与火力发电耦合互补方式,并以电厂的千瓦时耗煤量为指标对3种太阳能光热与火力发电耦合互补方式进行了分析,得出采用四级换热的太阳能光热与火力发电互补方式的千瓦时耗煤量最低。     

Potential of a parabolic trough solar concentrator for electric energy production

At present, parabolic trough technology is considered as the most low‐cost and powerful large‐scale technology to utilize solar energy for electricity generation and produce steam for different industrial usages. This article recommends the generation of electricity by using a parabolic trough solar concentrator in the central area of the Kingdom of Saudi Arabia (KSA) at Dawadmi city. Pressurized water is used as the heat‐transfer working fluid. A computer algorithm was built using the Matlab program to simulate the performance parameters of the Euro Trough collector (ETC). The input data included the properties of the working fluid (pressurized water) and the designing parameters of ETC. The output data were the outlet water temperature, the coefficient of heat transfer, the heat loss, and the thermal, solar, and global efficiencies. The obtained results indicated the ability of this type of parabolic trough in KSA to generate electric power due to the high‐performance parameters achieved. Also, the validity of using the simulation technique was measured and it showed good conformity.     

Technical and economical system comparison of photovoltaic and concentrating solar thermal power systems depending on annual global irradiation

Concentrating solar thermal power and photovoltaics are two major technologies for converting sunlight to electricity. Variations of the annual solar irradiation depending on the site influence their annual efficiency, specific output and electricity generation cost. Detailed technical and economical analyses performed with computer simulations point out differences of solar thermal parabolic trough power plants, non-tracked and two-axis-tracked PV systems. Therefore, 61 sites in Europe and North Africa covering a global annual irradiation range from 923 to 2438 kW h/m² a have been examined. Simulation results are usable irradiation by the systems, specific annual system output and levelled electricity cost. Cost assumptions are made for today's cost and expected cost in 10 years considering different progress ratios. This will lead to a cost reduction by 50% for PV systems and by 40% for solar thermal power plants. The simulation results show where are optimal regions for installing solar thermal trough and tracked PV systems in comparison to non-tracked PV. For low irradiation values the annual output of solar thermal systems is much lower than of PV systems. On the other hand, for high irradiations solar thermal systems provide the best-cost solution even when considering higher cost reduction factors for PV in the next decade. Electricity generation cost much below 10 Eurocents per kW h for solar thermal systems and about 12 Eurocents/kW h for PV can be expected in 10 years in North Africa.     

对太阳能热发电走向成功之路的思考

从理论方面对降低太阳能热发电投资成本的方式进行了分析,认为可通过扩大规模来降低投资成本,依靠扩大发电系统的规模和优化镜场设计来提高太阳能热发电系统的光电转换效率;碟式和点聚焦菲涅耳聚光系统的光热转换效率高,竞争力较强。当采用超大功率蒸汽轮机时,可使发电系统的规模扩大10倍、热电转换效率提高25%;按照光学效率和接收器热效率均达到92%计算,碟式聚光系统的光热转换效率可达到84.64%,而塔式聚光系统的光热转换效率为57.73%,前者比后者提高了46.62%,使碟式太阳能热发电系统的光电转换效率比塔式太阳能热发电系统的提高了83.3%,从而使碟式太阳能热发电系统的总投资成本比塔式太阳能热发电系统的下降了45.4%,共用跟踪系统使其总投资成本又下降了4.8%,再加上碟式太阳能热发电系统的中发电系统规模扩大10倍,最终,碟式太阳能热发电系统的总投资成本可比塔式太阳能热发电系统的降低75.2%。在不考虑材料和制造技术方面进步的情况下,太阳能热发电的上网电价可从目前的1元/kWh降至约0.25元/kWh,使太阳能热发电成为未来有竞争力的主要能源技术。     

Energy performance enhancement of solar thermal power plants by solar parabolic trough collectors and evacuated tube collectors-based preheating units

Solar steam power plant is the dominant technology in the category of solar thermal power systems. In steam power cycles, there is usually a couple of steam lines, extracted from medium-pressure and low-pressure turbines, to preheat the working fluid before the boiler. This although leads to an increase in the energy efficiency of the cycle, reduces the contribution of the turbine proportionally. Therefore, finding an alternative method of preheating the working fluid would be effective in further enhancement of the efficiency of the system. In this study, the feasibility of using solar collectors for the preheating process in a solar steam power plant is investigated. For this, parabolic trough solar collectors and evacuated tube solar collectors based on a wide range of different scenarios and configurations are employed. The plant is designed, sized and thermodynamically analyzed for a case study in Saudi Arabia where there is a large solar irradiation potential over the year. The results of the simulations show that, among all the considered scenarios, a power cycle aided by a set of parabolic trough collectors as the preheating unit is the best choice technically. This configuration leads to about 23% increased power generation rate and 6.5% efficiency enhancement compared to the conventional design of the plant.     

高温相变蓄热技术的研究进展

蓄热技术不仅能缓解环境污染和能源浪费的问题,还可以解决热能供给与需求失的矛盾.文中对高温相变蓄热技术的应用和研究现状做了一个综述,从蓄热材料的选择、蓄热器的数值模拟和数学建模、系统研究三个方面对高温相变蓄热技术的研究进展热点以及现状进行了总结.尤其对高温相变蓄热技术在太阳能热发电中的应用现状,并对高温相变蓄热技术在太阳能热发电中的应用进行了分析和展望.     

槽式和塔式太阳能热发电的热效率及环境影响分析与评价

选取槽式和塔式两种太阳能热发电系统为研究对象,运用生命周期方法（Life Cycle Assessment,LCA）分别对槽式和塔式太阳能热发电进行系统、全面的环境影响评价。主要对两种太阳能热发电的用材、生产和运输3个阶段进行分析,分别计算了3个阶段的单位能耗和环境影响,并对两个系统的分析结果进行比较。同时,采用朗肯循环对两种系统进行了热效率方面的比较。     

太阳能高温热发电蓄热技术研究进展

对应用于太阳能高温热发电的各种蓄热原理、蓄热介质和蓄热过程进行了详细的分析和比较.以混凝土或铸造陶瓷为介质的蓄热方法投资成本低,多用于槽式发电系统中;以熔盐作为介质的双罐蓄热系统技术风险低、可实现连续、稳定发电,较适用于塔式系统;斜温层单罐蓄热系统技术风险相对较高,但其投资成本可以降低;直接蒸汽发电系统对传输系统的耐压提出了非常高的要求.高温相变蓄热和化学反应蓄热技术还处于实验研究阶段,需要寻找更合适的相变材料、热化学反应和装置.     

Conceptual design and techno-economic assessment of integrated solar combined cycle system with DSG technology

Direct steam generation (DSG) in parabolic trough collectors causes an increase to competitiveness of solar thermal power plants (STPP) by substitution of oil with direct steam generation that results in lower investment and operating costs. In this study the integrated solar combined cycle system with DSG technology is introduced and techno-economic assessment of this plant is reported compared with two conventional cases. Three considered cases are: an integrated solar combined cycle system with DSG technology (ISCCS-DSG), a solar electric generating system (SEGS), and an integrated solar combined cycle system with HTF (heat transfer fluid) technology (ISCCS-HTF).This study shows that levelized energy cost (LEC) for the ISCCS-DSG is lower than the two other cases due to reducing O&M costs and also due to increasing the heat to electricity net efficiency of the power plant. Among the three STPPs, SEGS has the lowest CO₂ emissions, but it will operate during daytime only.     

Energy performance and numerical optimization of a screw expander–based solar thermal electricity system in a wide range of fluctuating operating conditions

This paper provides fundamental principles to study the thermodynamic performance of a new screw expander–based solar thermal electricity plant. While steam turbines are generally used in direct steam generation solar systems without admitting fluid in two-phase conditions, steam screw expanders, as volumetric machines, can convert thermal to mechanical energy also by expanding liquid-steam mixtures without a decline in efficiency. In effect, steam turbines are not as competitive as screw expanders when the net power is smaller than 2 MW and for low-grade heat sources. The solar electricity generation system proposed in this paper is based on the steam Rankine cycle: Water is used as both working fluid and storage, parabolic trough collectors are used as a thermal source, and screw expanders are used as power machines. Since screw expanders can operate at off-design working conditions in several situations when installed in direct steam generation solar plants, studying expander performance under fluctuating working situations is a crucial issue. The main aim of the present paper is to establish a thermodynamic model to study the energetic benefits of the proposed power system when off-design operating conditions and variable solar radiation occur. This entails, first and foremost, developing overexpansion and underexpansion numerical models to describe the polytropic expansion phase, which considers all the losses affecting performance of the screw expander under real operating conditions. To assess the best operating conditions and maximum efficiency of the whole power system at part-load working conditions under fluctuating solar radiations, parametric optimization is then improved in a wide range of variable working conditions, assuming condensation pressures of water increasing from 0.1 to 1 bar, under an evaporation temperature rising from 170°C to 300°C.     

An estimation of the performance limits and improvement of dry cooling on trough solar thermal plants

A study is reported of the potential performance of dry cooling on power generation. This is done in the context of a generic trough solar thermal power plant. The commercial power plant analysis code GateCycle is applied for this purpose. This code is used to estimate typical performance of both wet and dry cooling options. Then it is configured to estimate the performance of ideal wet and dry cooling options. The latter are defined as the condenser temperature being at the ambient wet bulb temperature or dry bulb temperature, respectively. Yearly power production of a solar power plant located in Las Vegas is presented for each of the cooling options. To move further toward approaching the possible improvement in dry cooling, the impact of a high-performance heat exchanger surface is evaluated. It is found that higher efficiency generation compared to current dry cooling designs is definitely possible. In fact the performance of these types of systems can approach that of wet cooling system units.