槽式太阳能热发电站的模拟优化

通过SAM(System Advisor Model)软件,在中国4个地区模拟建设槽式太阳能热发电站进行研究。经过模拟分析,在该文所设定的槽式太阳能系统参数下,拉萨市槽式电站性能最好,对该地区3种不同集热蓄热工质组合的80 MW槽式电站做进一步模拟优化和对比分析,分别以年发电量、年发电效率和平准化电度成本(LCOE)为优化目标,得到不同槽式电站的最佳太阳倍数和蓄热时长;对导热油-太阳盐(Solar Salt)槽式电站,进一步模拟其蓄热系统的不同调度方案和集热工质的不同出口温度对电站的年发电量和镜场吸热效率等性能参数的影响,通过对比分析,得出集热蓄热工质均为低熔点四元盐的槽式电站的各项性能参数最为理想。     

太阳能热发电技术的进展及现状

介绍了槽式、塔式和盘式太阳能热利用发电站的发展史和技术现状.指出槽式太阳能热发电站的功率可至1000MW,是所有太阳能热发电站中功率最大的,其年收益也最高.塔式太阳能热利用发电站的功率可至100MW,与槽式系统相比,在商业上还不成熟.但高温型塔式系统和燃气轮机混合发电或和混合发电站联合发电最具市场化前景.盘式太阳能热发电系统功率5～1000kW,它用在流动场所,应用范围大,除可满足用电需求,还可代替柴油机组.     

储热系统对槽式太阳能热发电系统的影响研究

以美国达科特地区建设的50MW槽式热电站为模型,利用SAM软件对配备储热系统的槽式太阳能系统的运行和经济情况进行分析,并从发电量、设备利用率及发电成本等方面讨论了蓄热系统对槽式太阳能热发电系统的影响。     

槽式太阳能热发电站中导热油的低温分步注油工艺流程介绍

中国广核新能源控股有限公司投建并已投产的德令哈50 MW槽式太阳能热发电站是我国国内首座建设在高寒地区的大型槽式太阳能热发电站。该电站以导热油作为传热工质,但由于高寒地区的气温在绝大部分时间不能满足导热油的注入条件,且无相关的低温条件下注入导热油的经验,导致在此气候条件下注入导热油存在风险高、难度大的问题。针对在该热发电站中需注入的导热油量大、导热油系统复杂、管道多、管道直径细、导热油常温下凝结(凝结点为12℃)等特点,提出了一套成熟的低温分步注油工艺流程。该工艺流程将整个导热油系统注油分成多个小单元实行分批注入,并采取了提高初始注油温度、利用集热管集热、利用热空气对系统管道进行加热、通过排放阀排放管道端部的低温导热油等措施。通过实际验证,采用该低温分步注油工艺最终成功实现了在冬季时对德令哈50 MW槽式太阳能热发电站注入导热油。以期将该低温分步注油工艺流程广泛应用于国内西北地区及其他类似气候条件下的槽式太阳能热发电站的建设过程中。     

两种典型集成方式下太阳能辅助燃煤机组发电系统热性能对比分析

基于热力学第一定律和质量守恒定律,建立槽式太阳能辅助燃煤发电系统模型。并针对槽式太阳能辅助燃煤机组回热系统最常见的两种集成方式,以槽式太阳能辅助某330 MW亚临界燃煤机组为研究对象,基于典型年气象数据及原燃煤机组年实际负荷,对这两种集成互补方案进行分析比较,并在此基础上,定量分析蓄热对互补发电系统年性能的影响。结果表明:串联集成方式在运行调节及系统控制方面更易实施,但并联集成互补系统具有更好的热经济性;此外,蓄热能大幅减小太阳能间歇性造成的集热子系统输出波动,且对于有条件设置较大集热面积的互补系统,加入蓄热可使其获得更好的经济性。     

槽式太阳能热发电站的性能研究

采用SAM软件对槽式太阳能热发电站进行模拟,研究了纬度、季节变换、太阳倍数、储热时长等因素对太阳能热发电站性能的影响。研究结果表明,纬度和季节变换对电站镜场余弦效率和光学效率有很大影响,纬度越高,电站镜场余弦效率和光学效率越低;夏季的余弦效率和光学效率最高,冬季最低。优化设计太阳倍数和储热时长,以获得最佳的聚光集热系统和储热系统配置,结果表明:对于装机容量为50 MW的太阳能热发电站而言,在太阳倍数为2.0、储热时长为15 h的组合下,可以获得较好的电站性能。     

槽式太阳能热发电站的设计

针对槽式热发电系统的集热器进行分析,讨论了集热器的光学效率和集热管热损失模型,在此基础上利用Solar Advisor model 2010软件并结合经验数据,模拟和计算了槽式太阳能热发电系统的集热器面积,为槽式太阳能热发电站设计提供理论依据。     

槽式太阳能光热电站集热系统分区数对系统性能的影响

以某50 MW槽式太阳能光热电站为模拟对象,依据电站的主要参数,建立槽式太阳能热发电系统模型,分析了集热系统分区数、回路数和储热时长对年净发电量和平准化度电成本的影响。结果表明：50 MW槽式太阳能光热电站的单回路中集热器数量以4个为最佳,最佳集热系统分区数为6,最佳储热时长为16 h。     

带储热装置的太阳能辅助燃煤发电系统研究

为克服太阳能间歇性对太阳能辅助燃煤发电系统的影响,针对某350 MW燃煤发电机组,提出带储热装置的槽式太阳能辅助燃煤发电系统。在该系统中,并列设置蓄热装置,白天经太阳集热器加热的导热油一部分进入油水换热器,用于加热火电机组的给水,另一部分进入蓄热装置储存热量供夜间加热给水时使用。以某地春分日的太阳能日辐照度数据为例,进行系统的方案设计,利用EBSILON软件,对该系统的热力性能进行模拟,结果表明,与原燃煤发电机组相比,系统一天可节约标准煤26.3 t。以17:00对应的太阳辐照度数据为依据,设计填充床储热罐布置数量,并对其温度场进行数值模拟。     

槽式太阳能热发电站中槽式集热器桩基础的施工工艺研究

以某槽式太阳能热发电站的集热场施工工程为例,在国内尚无相关成熟施工工艺的现状下,针对槽式集热器桩基础施工工程量大,以及地脚螺栓施工精度高、工期紧的特点,对槽式集热器桩基础及地脚螺栓安装、固定的施工工艺进行了研究。在满足工程实践需求的前提下,从桩基础点位测量、桩基础成孔、钢筋笼的制作与安装、地脚螺栓固定架的设计和制作、地脚螺栓的安装及固定、混凝土浇筑等各方面对槽式集热器桩基础施工工艺流程进行了多次论证和现场实际验证,最终提出了一套独特的槽式太阳能热发电站中槽式集热器桩基础的施工工艺。通过实际工程验证,该槽式集热器桩基础施工工艺有效控制了地脚螺栓的施工质量,从而确保了槽式集热器的安装精度,并在大幅加快现场施工进度的基础上满足了工程的施工要求。该施工工艺可广泛应用于其他大规模槽式太阳能热发电站的槽式集热器桩基础施工中。     

The application of parabolic trough technology under Jordanian climate

Parabolic trough solar thermal power plants are a proven technology in the utility scale since mid of the eighties. Between 1984 and 1991 nine power plants with an overall capacity of 354 MW have been installed in the Mojave Desert in California. Since, these power plants can be equipped with a thermal storage or a fossil back-up they offer a fully dispatchable electricity generation capacity. This technology will be a very interesting near term option for countries with high solar irradiation levels and small resources of fossil fuels like Jordan.This paper, discusses the use of parabolic trough solar thermal power plants for electricity production under Jordanian climate for two different sites (Amman, and Ma'an). An analysis of the daily power output, direct normal irradiation and the efficiency for the two sites has been carried out. The results showed that Ma'an site would be preferred than Amman site, so that it is recommended to erect the Parabolic Trough Concentrator (PTC) plant in the southern region of Jordan.Also this study aims to encourage the Jordanian government and the private sector to implement the solar thermal power plants for future expansion of power sector due to the increasing electricity demand and environmental degradation.     

对我国发展太阳能热发电的一点看法

太阳能热发电是大规模开发利用太阳能的一个重要技术途径。由于关键技术有待重大突破,目前国外塔式、槽式、碟式系统都还面临着投资大、成本高的问题。本文分析了塔式、槽式、碟式现行三种技术路线在我国推广应用的技术难点,提出了一个新型分立式太阳能热发电技术路线。这项新技术建立在太阳聚光跟踪理论突破的基础之上,不仅具有完全自主知识产权,而且比国外现行的热发电技术更为经济高效。     

浅析太阳能光热发电技术的发展

介绍了太阳能光热发电的工作原理及系统的基本组成形式:槽式、塔式、碟式,并简要介绍了国内外光热发电技术的发展历程及前景.     

Combined solar organic Rankine cycle with reverse osmosis desalination process: Energy,exergy, and cost evaluations

Organic Rankine cycles (ORC) have unique properties that are well suited to solar power generation. In this work design and performance calculations are performed using MatLab/SimuLink computational environment. The cycle consists of thermal solar collectors (Flat Plate Solar Collector (FPC), or Parabolic Trough Collector (PTC), or Compound Parabolic Concentrator (CPC)) for heat input, expansion turbine for work output, condenser unit for heat rejection, pump unit, and Reverse Osmosis (RO) unit. Reverse osmosis unit specifications used in this work is based on Sharm El-Shiekh RO desalination plant. Different working fluids such as: butane, isobutane, propane, R134a, R152a, R245ca, and R245fa are examined for FPC. R113, R123, hexane, and pentane are investigated for CPC. Dodecane, nonane, octane, and toluene are allocated for PTC. The proposed process units are modeled and show a good validity with literatures. Exergy and cost analysis are performed for saturation and superheated operating conditions. Exergy efficiency, total exergy destruction, thermal efficiency, and specific capital cost are evaluated for direct vapor generation (DVG) process. Toluene and Water achieved minimum results for total solar collector area, specific total cost and the rate of exergy destruction.     

Comparative system analysis of direct steam generation and synthetic oil parabolic trough power plants with integrated thermal storage

Parabolic trough power plants are currently the most commercially applied systems for CSP power generation. To improve their cost-effectiveness, one focus of industry and research is the development of processes with other heat transfer fluids than the currently used synthetic oil. One option is the utilization of water/steam in the solar field, the so-called direct steam generation (DSG).Several previous studies promoted the economic potential of DSG technology (Eck et al., 2008b, Price et al., 2002, Zarza, 2002). Analyses’ results showed that live steam parameters of up to 500 °C and 120 bars are most promising and could lead to a reduction of the levelized electricity cost (LEC) of about 11% (Feldhoff et al., 2010). However, all of these studies only considered plants without thermal energy storage (TES).Therefore, a system analysis including integrated TES was performed by Flagsol GmbH and DLR together with Solar Millennium AG, Schott CSP GmbH and Senior Berghöfer GmbH, all Germany. Two types of plants are analyzed and compared in detail: a power plant with synthetic oil and a DSG power plant. The design of the synthetic oil plant is very similar to the Spanish Andasol plants (Solar Millennium, 2009) and includes a molten salt two-tank storage system. The DSG plant has main steam parameters of 500 °C and 112 bars and uses phase change material (PCM) for the latent and molten salt for the sensible part of the TES system. To enable comparability, both plants share the same gross electric turbine capacity of 100 MWel, the same TES capacity of 9 h of full load equivalent and the same solar multiple of the collector field of about two.This paper describes and compares both plants’ design, performance and investment. Based on these results, the LEC are calculated and the DSG plant’s potential is evaluated. One key finding is that with currently proposed DSG storage costs, the LEC of a DSG plant could be higher than those of a synthetic oil plant. When considering a plant without TES on the other hand, the DSG system could reduce the LEC. This underlines the large influence of TES and the still needed effort in the development of a commercial storage system for DSG.     

Assessment and optimization of an integrated energy system with electrolysis and fuel cells for electricity,cooling and hydrogen production using various optimization techniques

In this research study, a novel integrated solar based combined, cooling, heating and, power (CCHP) is proposed consisting of Parabolic trough solar collectors (PTSC) field, a dual-tank molten salt heat storage, an Organic Rankine Cycle (ORC), a Proton exchange membrane fuel cell (PEMFC), a Proton exchange membrane electrolyzer (PEME), and a single effect Li/Br water absorption chiller. Thermodynamics and economic relations are used to analyze the proposed CCHP system. The mean of Tehran solar radiation as well as each portion of solar radiation during 24 h in winter is obtained from TRNSYS software to be used in PTSC calculations. A dynamic model of the thermal storage unit is assessed for proposed CCHP system under three different conditions (i.e., without thermal energy storage (TES), with TES and with TES + PEMFC). The results demonstrate that PEMFC has the ability to improve the power output by 10% during the night and 3% at sunny hours while by using TES alone, the overnight power generation is 86% of the power generation during the sunny hours. The optimum operating condition is determined via the NSGA-II algorithm with regards to exergy efficiency and total cost rate as objective functions where the optimum values are 0.058 ($/s) and 80%, respectively. The result of single objective optimization is 0.044 ($/s) for the economic objective in which the exergy efficiency is at its lowest value (57.7%). In addition, results indicate that the amount of single objective optimization based on exergetic objective is 88% in which the total cost rate is at its highest value (0.086 $/s). The scattered distribution of design parameters and the decision variables trend are investigated. In the next step, five different evolutionary algorithms namely NSGA-II, GDE3, IBEA, SMPSO, and SPEA2 are applied, and their Pareto frontiers are compared with each other.     

Heat transfer analysis of parabolic trough solar receiver

Solar Parabolic Trough Collectors (PTCs) are currently used for the production of electricity and applications with relatively higher temperatures. A heat transfer fluid circulates through a metal tube (receiver) with an external selective surface that absorbs solar radiation reflected from the mirror surfaces of the PTC. In order to reduce the heat losses, the receiver is covered by an envelope and the enclosure is usually kept under vacuum pressure. The heat transfer and optical analysis of the PTC is essential to optimize and understand its performance under different operating conditions. In this paper a detailed one dimensional numerical heat transfer analysis of a PTC is performed. The receiver and envelope were divided into several segments and mass and energy balance were applied in each segment. Improvements either in the heat transfer correlations or radiative heat transfer analysis are presented as well. The partial differential equations were discretized and the nonlinear algebraic equations were solved simultaneously. Finally, to validate the numerical results, the model was compared with experimental data obtained from Sandia National Laboratory (SNL) and other one dimensional heat transfer models. Our results showed a better agreement with experimental data compared to other models.     

Recent Developments in Integrated Solar Combined Cycle Power Plants

Global concern for depleting fossil fuel reserves have been compelling for evolving power generation options using renewable energy sources. The solar energy happens to be a potential source for running the power plants among renewable energy sources. Integrated Solar Combined Cycle(ISCC) power plants have gained popularity among the thermal power plants. Traditional ISCC power plants use Direct Steam Generation(DSG) approach. However, with the DSG method, the ISCC plant’s overall thermal efficiency does not increase significantly due to variations in the availability of solar energy. Thermal Energy Storage(TES) systems when integrated into the solar cycle can address such issues related to energy efficiency, process flexibility, reducing intermittency during non-solar hours. This review work focuses and discusses the developments in various components of the ISCC system including its major cycles and related parameters. The main focus is on CSP technologies, Heat Transfer Fluid(HTF), and Phase Change Material(PCM) used for thermal energy storage. Further, study includes heat enhancement methods with HTF and latent heat storage system. This study will be beneficial to the power plant professionals intending to modify the solar-based Combined Cycle Power Plant(CCPP) and to retrofit the existing Natural Gas Combined Cycle(NGCC) plant with the advanced solar cycle.     

The environmental and cost implications of solar energy preferences in Renewable Portfolio Standards

Many state-level Renewable Portfolio Standards (RPS) include preferences for solar generation, with goals of increasing the generation diversity, reducing solar costs, and encouraging local solar industries. Depending on their policy design, these preferences can impact the RPS program costs and emissions reduction. This study evaluates the impact of these policies on costs and emissions, coupling an economic dispatch model with optimized renewable site selection. Three policy designs of an increased RPS in Michigan are investigated: (1) 20% Solar Carve-Out, (2) 5% Distributed Generation Solar Carve-Out, and (3) 3× Solar Multiplier. The 20% Solar Carve-Out scenario was found to increase RPS costs 28%, while the 5% Distributed Generation Solar Carve-Out increased costs by 34%. Both of these solar preferences had minimal impact on total emissions. The 3× Solar Multiplier decreases total RPS program costs by 39%, but adds less than half of the total renewable generation of the other cases, significantly increasing emissions of CO₂, NO_x, and SO₂ relative to an RPS without the solar credit multiplier. Sensitivity analysis of the installed cost of solar and the natural gas price finds small changes in the results of the Carve-Out cases, with a larger impact on the 3× Solar Multiplier.