线性菲涅尔反射式太阳能热发电系统研究进展及应用

介绍了线性菲涅尔反射式太阳能热发电系统的特点及及其优点,论述了现阶段对线性菲涅尔反射式太阳能热发电系统最新的理论及实验研究进展,最后介绍了线性菲涅尔反射式太阳能热发电站的应用情况。     

一种圆柱面线聚焦菲涅尔式太阳能中温集热系统的研究

介绍了一种利用圆柱面线聚焦菲涅尔镜组成的太阳能集热系统,该系统主要由圆柱面线聚焦菲涅尔镜、二次聚光器、太阳跟踪器、加热油箱和负载等部件组成;给出了圆柱面线聚焦菲涅尔镜的设计思路,利用注塑成型方法生产出圆柱面线聚焦菲涅尔镜,然后利用该镜搭建线聚光太阳能中温集热系统,并在实际天气下对系统性能进行测试。结果表明,在日照充分的天气下,本系统的平均集热效率约为40%,集热效果良好。     

基于DSP的线性菲涅尔太阳能集热系统设计与实现

针对线性菲涅尔太阳能集热系统普遍存在遮挡和阴影等特点,提出了一种设计方法,并设计了一套线性菲涅尔太阳能集热系统。在该系统中,镜场微弧面反射镜按照一定初始角度安装,并通过设计的DSP单轴跟踪控制器,控制反射镜跟踪太阳,将太阳光线反射到镜场上方固定安装的三角形腔体吸收器上,实现太阳能集热。通过精度检测实验和光学镜场模型仿真,验证了该系统应用于线性菲涅尔太阳能的正确性和可行性。     

基于三角腔体吸收器的透射式菲涅尔定焦线系统聚光特性分析

为解决线性菲涅尔太阳能集热系统单轴跟踪过程中出现的聚光焦线偏移以及降低系统跟踪能耗等问题,提出一种透射式菲涅尔定焦线太阳能聚光器.该聚光器采用极轴跟踪方式与线性菲涅尔透镜定期滑移调节方式相结合,可实现固定焦线聚光.将该聚光器与三角腔体吸收器所组成的太阳能集热系统,利用基于蒙特卡罗光线追迹法的TracePro光学软件分析...     

一种采用腔体吸收器的线性菲涅尔太阳集热器性能分析与优化

通过理论与实验的方法,对一种采用方形腔体吸收器的线性菲涅尔太阳集热器的集热性能进行研究,分析影响菲涅尔集热器光学性能和集热性能的影响因素,通过Matlab编程模拟集热器的集热性能,并由实验测试进行验证。该集热器的光学效率为78.6%,最高集热温度为180℃,在集热温度80~150℃的范围内,集热效率从52.3%变化到36.2%,热损系数从9.5 W/(m~2?K)升至22.8 W/(m~2?K)。与此同时,通过Trace Pro软件模拟,对集热器的设计结构进行优化分析。研究表明:该菲涅尔太阳集热器具有良好的集热性能,在适宜的天气条件下运行稳定可靠,且具有易搭建、维护简单和技术经济性好的特点,在中温太阳能的热利用领域具有良好的应用前景。     

跟踪及安装精度对菲涅尔定向光输运装置的影响

该文基于对菲涅尔定向装置的研究，搭建其集热性能测试实验平台，并采用TracePro光学模拟软件，建立菲涅尔定向光输运装置的光学模型。在进行模型验证后，模拟分析跟踪误差和安装误差对光学效率的影响。研究结果表明：俯仰角、旋转角的跟踪误差会导致菲涅尔定向光输运装置光学效率的降低，并且俯仰电机误差范围应控制在±0.1°，方位电机误差范围应控制在±0.5°；当菲涅尔定向光输运装置中定向光输运器抛物反射面的焦点与菲涅尔透镜的聚光焦点存在安装误差时，菲涅尔定向光输运装置光学效率普遍下降，最大偏移量不宜超过0.1。但当偏移量不超过0.5时，将定向光输运器向下侧偏移或将菲涅尔透镜向上偏移，有利于提高菲涅尔定向光输运装置（LTF-SC）光学效率。该研究结果为菲涅尔定向光输运装置和菲涅尔中央接收式太阳能高温集热系统领域的研究和应用提供参考。     

复合抛物面聚光器在线性菲涅尔聚光上的应用

简述了线性菲涅尔的聚光原理及国外研发机构的相关应用现状,针对聚光器面临的技术难题,研制出一种复合抛物面聚光器,简要介绍其组成结构及反光板曲面形状.结合该技术在世界首座屋顶式太阳能菲涅尔热发电站上的应用并经过相关测试.论证了此聚光器技术具有明显的优势和广阔的应用前景,提高了线性菲涅尔聚光集热器在太阳能热发电、中温工业应用等领域的市场竞争力.     

基于线性菲涅尔反射镜的二次反射塔式太阳集热器性能分析

提出基于线性菲涅尔反射镜的二次反射塔式太阳集热器的设计原理,设计一个由3组定日镜组成的小型塔式集热器,分析塔式集热器的光学性能,当光线垂直入射时,其光学效率可达65%。搭建基于线性菲涅尔反射镜的二次反射塔式集热系统实验台。测试结果表明,入口温度110℃时,热效率为51.6%;工质进口温度110℃时,热损失系数为38.6 W/(m~2·℃),热损失为583.4 W。     

太阳能蓄热空气罐供暖系统实验研究

菲涅尔透镜式太阳能集热器具有环保、经济和结构简单等优点。文章利用带有自动跟踪控制系统的小型菲涅尔透镜式太阳能蓄热空气罐对空气进行循环加热,通过观测太阳辐射强度、外界环境温度以及通风管出口温度的变化情况,分析太阳能蓄热空气罐供暖系统的各项性能。分析结果表明:太阳能蓄热空气罐供暖系统集热效率的最大值可以达到60%;通风管出口温度比环境温度约高出50℃。利用太阳能蓄热空气罐供暖系统在冬季进行供暖是可行的。     

反射式线性菲涅尔集热器性能的实验研究与模拟分析

采用热网络法建立菲涅尔集热系统CPC腔式接收器的数值传热模型,搭建集热器系统,实验研究集热器效率、CPC腔的集热性能。利用数值传热模型分析太阳辐照度、镜场宽度、工质入口温度和质量流量的变化对系统出口温度和效率的影响,以期为菲涅尔集热器出口参数的控制提供依据。实验数据验证了模型的有效性,模拟结果显示,质量流量对工质出口参数影响最大;镜场宽度和辐照度对集热效率的影响最为显著;菲涅尔集热器的热效率可达68%。     

Investigation of temperature distribution on a new linear Fresnel receiver assembly under high solar flux

A linear Fresnel collector design with an operation temperature of 300°C or above typically requires a solar flux concentration ratio of at least 20 on the surfaces of the receiver assembly. For the commercial linear Fresnel collector design in this work, the receiver assembly includes a secondary reflector and an evacuated receiver tube. The high‐concentration solar flux may impose additional operating‐temperature requirements on the secondary reflector and receiver tube. Thus, a careful heat‐transfer analysis is necessary to understand the operating temperature of the receiver assembly component surfaces under design and off‐design conditions to guide appropriate material selections. In this work, a numerical heat‐transfer analysis is performed to calculate the temperature distribution of the surfaces of the secondary reflector and receiver glass envelope for a commercial collector design. Operating conditions examined in the heat‐transfer analysis include various wind speeds and solar concentration ratios. The results indicate a surface temperature higher than 100°C on the secondary reflector surface, which suggests that a more advanced secondary reflector material is needed. The established heat‐transfer model can be used for optimization of the other types of linear Fresnel collectors.     

Thermal performance of linear Fresnel reflecting solar concentrator with trapezoidal cavity absorbers

Thermal performance of the four identical trapezoidal cavity absorbers for linear Fresnel reflecting solar device were studied and compared. The absorbers were designed for operating in conjunction with a prototype Fresnel solar reflector. Rectangular and round pipe sections were used as absorber by placing in the trapezoidal cavity. The absorber pipes were coated with ordinary dull black board paint and black nickel selective surface. The bottom of the cavity was provided with plane glass to allow the solar radiation to be reflected from the Fresnel reflector. The other three sides of the cavity absorber were insulated to reduce heat loss. Thermal performance of the Fresnel reflecting concentrator with each trapezoidal cavity absorber was studied experimentally at different concentration ratio of the reflector. The study revealed that the thermal efficiency was influenced by the concentration ratio and selective surface coating on the absorber. The thermal efficiency decreased with the increase in the concentration ratio of the Fresnel reflecting collector. The selective surface coated absorber had a significant advantage in terms of superior thermal performance as compared to ordinary black painted absorber. The round pipe (multi-tube) receiver had higher surface area to absorb solar energy as compared to rectangular pipe receiver. Thermal efficiency of the solar device with round pipe absorber was found higher (up to 8%) as compared to rectangular pipe absorber.     

一种基于新结构的线性腔式太阳能集热器研究

提出一种适用于槽式太阳能热发电系统的新型线性腔式集热器。通过Tracepro模拟聚光镜焦距、弧形结构及开口宽度对系统光学性能的影响;采用热网络模型对该集热器的传热性能进行参数化研究,确定优化的集热器结构为优弧型,开口宽度为70 mm,与其匹配的聚光镜焦距为2100 mm。研究结果表明,当太阳直射辐射强度为500 W/m2,集热温度为650 K时,系统光热转换效率达65.3%。与一类传统真空管集热器的对比表明,该新型线性腔式集热器的集热性能优于UVAC Cermet直通式真空管集热器。另外,该线性腔式集热器生产和维护成本明显低于真空管集热器,对于促进槽式太阳能热发电技术具有重要意义。     

Review on Development of Small Point-Focusing Solar Concentrators

The technology of small point-focusing concentrator of solar energy has been developing rapidly in recent years owing to its compact structure and high collecting efficiency. This report presents important developments of small point-focusing concentrator in the past decade. This kind of solar concentrator refers to the parabolic dish concentrator, the point-focusing Fresnel lens, and the Scheffler reflector. Technological advances of these concentrators and the related performances have been presented. There are three main mirror fabrication technologies for dish concentrator, which are high polishing metal, silver-glass mirror and vacuum-membrane. Polymethyl methacrylate is widely used as material in Fresnel lens. Many scholars have proposed new lens shape to improve the uniformity of focusing. The Scheffler reflector has a characteristic of fixed focus, but its design parameters are not perfect so current research focuses on the theoretical calculation of the mirror. In addition, typical applications of the small point-focusing concentrator in photovoltaic system, solar thermal system, solar chemical system, and day-lighting system are summarized. Upon listing the important publications in open literature, a category of main applications of such kind of solar collector is provided based on the working characteristics of the system.     

Solar absorption cooling plant in Seville

A solar/gas cooling plant at the Engineering School of Seville (Spain) was tested during the period 2008-2009. The system is composed of a double-effect LiBr + water absorption chiller of 174 kW nominal cooling capacity, powered by: (1) a pressurized hot water flow delivered by mean of a 352 m² solar field of a linear concentrating Fresnel collector and (2) a direct-fired natural gas burner. The objective of the project is to indentify design improvements for future plants and to serve as a guideline. We focused our attention on the solar collector size and dirtiness, climatology, piping heat losses, operation control and coupling between solar collector and chiller. The daily average Fresnel collector efficiency was 0.35 with a maximum of 0.4. The absorption chiller operated with a daily average coefficient of performance of 1.1-1.25, where the solar energy represented the 75% of generator’s total heat input, and the solar cooling ratio (quotient between useful cooling and insolation incident on the solar field) was 0.44.     

太阳能集热系统结构与工质改进研究

对真空管式太阳能集热器的安装结构以及集热器内使用的工质进行改进.通过实验对比验证,改进后的集热系统具有更大的吸收比,新型纳米流体工质具有更高的集热效率.该改进的太阳能集热系统能在家用热水器、工业加热等方面广泛应用.     

非跟踪低倍聚光热管式真空管集热器的实验研究

太阳能是一种取之不尽用之不竭的清洁能源,但存在分散性强、能量密度低、不稳定等特点,因此为了得到高能量密度和稳定的能量供应,需要解决聚光和储能两大问题。针对这两个问题,本文采用非跟踪低倍聚光的集热器和保温效果良好的储热油箱,提出了一种非跟踪低倍聚光热管式真空管集热器;基于几何光学原理,模拟了热管式真空管和半圆聚光器的不同放置方式和位置的聚光效率,制作了半圆形聚光热管式真空管集热器系统,选择了合适的储热油箱并进行了保温效果的理论计算;最后对该系统进行了集热性能测试实验。实验结果表明,在半圆形聚光器的聚光下,系统的瞬时效率截距为0.66,热损系数为2.53 W/(m2•℃)。该系统完全能够满足人们的日常生活用热的需求,具有良好的应用前景。     

Geometrical designs and performance analysis of a linear fresnel reflector solar concentrator with a flat horizontal absorber

Two different approaches for designing a linear Fresnel reflector solar concentrator (LFRSC) with a flat horizontal absorber are described. The performance characteristics of both the designs are studied in detail. The distribution of local concentration ratio on the surface of the absorber, for each design, is investigated using the ray trace technique. Results of some typical numerical calculations are presented graphically and discussed.     

太阳能中温集热利用制蒸汽系统性能研究

构建了一套供热功率为310kW的太阳能中温集热利用制蒸汽系统,建立了系统主要模块——太阳能集热器与热変换器的热力学模型,研究了变工况下太阳辐射强度、凝水回收比、环境温度对系统效率和供热功率的影响,探讨了不同运行参数条件下集热温度与系统性能之间的关系。研究结果表明:增大辐射强度对系统性能提升显著;回收凝水对系统效率的影响不大,但对制热功率的提升较为明显;系统性能随环境温度升高呈先上升后下降的趋势;系统存在最佳集热温度,最佳集热温度随辐射强度和环境温度的增大而升高。