太阳能热发电系列文章(2)塔式与槽式太阳能热发电

塔式太阳能热发电塔式太阳能热发电系统也称集中型太阳能热发电系统。塔式太阳能热发电系统的基本形式是利用独立跟踪太阳的定日镜群,将阳光聚集到固定在塔顶部的接收器上,用以产生高温,加热工质产生过热蒸汽或高温气体,驱动汽轮机发电机组或燃气轮机发电机组发电,从而将太阳能转换为电能。     

一种高精度太阳位置算法

在聚光型太阳能热发电系统中,聚光装置需要实时跟踪太阳,以提高发电效率,在开环控制的太阳跟踪系统中,太阳位置的计算精度更为重要。比较了几种常用计算太阳位置的简单方法,并总结出一种算法简单的高精度太阳位置计算方法,此方法的高度角、方位角计算最大误差分别为0.05,°0.13°。     

用天文测量简历精确计算太阳位置的方法

在聚光型太阳能热发电系统中,聚光装置要实时跟踪太阳,须要根据计算出的太阳位置进行跟踪,以提高发电效率;在开环控制的太阳跟踪系统中,太阳位置的计算精度更为重要。文章给出了利用天文测量简历计算太阳位置的具体方法,其结果可以作为太阳视位置的相对标准,文章还将此方法的计算结果与一些经典算法的计算进行了比较。     

计科能源 与您共创清新世界

<正>公司简介北京市计科能源新技术开发公司从事太阳能光伏发电、风光互补发电和太阳能热利用等领域的产品开发、系统集成、预可研报告编制、工程设计安装等服务。太阳能自动跟踪系统简介太阳能自动跟踪系统根据每天太阳方位的规律性变化,通过系统的自动运转使得太阳能电池板始终保持对太阳的追踪,更高效的利用太阳能。凭借超过20年的专业经验,计科采用高质量、高可靠性的自动化器件和系统工具以及软件工具来实现系统运转,确保太阳能量以更有效地方式转化为电     

太阳跟踪装置的双模式控制系统

介绍了用于太阳跟踪装置控制系统中的两种控制模式结构、组成和工作原理。对该模式进行适当设置,即可用于太阳能热水器、太阳能屋顶发电、太阳能干燥器、太阳能电池、太阳灶、太阳能空调、太阳能路灯等各种太阳跟踪装置中,实现双模式控制。双模式控制系统具有较强的通用性和适应性。     

专利信息

●太阳能热利用压差式自动跟踪太阳灶本实用新型为一种压差式自动跟踪太阳灶,包括:灶体、反射镜、带有纬度调节器的调整支架、带有太阳赤纬角调节器的反射镜尾杆及其配重,如图1。调整支架上设有旋转轴,此旋转轴与     

一种大范围太阳光线自动跟踪方法

分析了聚光太阳能发电系统中目前常用的程序跟踪法和传感器跟踪法的特点,阐述了程序跟踪和传感器跟踪相结合实现精确跟踪的原理,并介绍了相应的控制方法和模拟跟踪装置的组成。这种方法可以利用低成本的角度传感器和四象限光电池实现太阳光线的精确跟踪,有利于降低跟踪系统的硬件成本。跟踪装置运行结果与SPA算法的结果比较,实测的跟踪误差不大于0.03°,满足高聚光比太阳能发电系统对太阳跟踪的要求。     

一种便携式单轴自动跟踪烧水发电两用太阳灶

设计并制作了一种便携式单轴自动跟踪烧水发电两用太阳灶。该太阳灶由铝合金支架、抛物面灶体、食品级不锈钢加热管、单轴自动跟踪装置、硬件模块组成;与传统产品相比,其体现了便携、节能、环保和自动跟踪太阳的特点,预计近期有潜在的市场前景。     

太阳能热发电高温蓄热技术

一前言太阳能热发电技术是除风电以外最有经济竞争力的可再生能源发电技术。太阳能集热器把收集到的太阳辐射能发送至接收器产生热空气或热蒸汽,用传统的电力循环来产生电能,具有技术成熟、发电成本低和容易与化石燃料形成混合发电系统的优点。太阳能高温蓄热技术是太阳能热发电的关键技术。由于太阳辐射强度时刻在变化,太阳能热发电系统在早晚或云遮间隙必须依靠储存的能量维持系     

新型太阳能发电装置

据苏联报刊报道,苏联亚美尼亚太阳能实验所的专家们建造了一种太阳能发电装置。这种装置的太阳能反射屏可自动跟踪着太阳的移动。自动系统既不用蓄电设备,也不用经常维修。这样,在边远和交通不便的地方也可以使用这种太阳能发电装置。     

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...     

Performance of Cylindrical Parabolic Collector with Automated Tracking System

Parabolic solar collector collects the radiant energy emitted from the sun and focuses it at a point. Parabolic trough collectors are the low cost implementation of concentrated solar power technology that focuses incident sun light on to a tube filled with a heat transfer fluid. However, the basic problem with the cylindrical parabolic collector without tracking was the solar collector does not move with the orientation of sun. Development of automatic tracking system for cylindrical parabolic collectors will increase solar collection as well as efficiency of devices. The main aim of this paper is to design, fabricate and analyze the performance of parabolic collector with automated tracking system. The automated tracking mechanism is used to receive the maximum possible energy of solar radiation as it tracks the path of sun. The performance of the parabolic trough collector is experimentally investigated with the water circulated as heat transfer fluid. The collector efficiency will be noted.     

基于复合控制的塔式太阳能跟踪控制装置设计

针对塔式太阳能热发电站中定日镜跟踪装置的跟踪精度不高、构建成本较大等问题,提出采用将遗传算法的选择机制与吸热塔能量变化的反馈机制相结合的方式对光热电站的太阳能跟踪控制系统进行改进.在光热电站的少数几台定日镜上配备光电检测元件,并以其控制角度为基准控制其他定日镜的角度调整.采用DSP(digital signal processing)为控制核心,完成了跟踪控制器的通讯框架及控制系统的硬件电路设计.实验表明,该方案在保证光热电站整体控制精度的基础上,减少了光电检测元件安装数量和电站构建成本,并保证了视日轨迹跟踪控制时的自动调整能力.     

A hybrid power generation system: solar‐driven Rankine engine–hydrogen storage

This paper reports on the feasibility of a hybrid power generation system consisting of a solar energy‐driven Rankine engine and a hydrogen storage unit. Solar energy, the power for the hybrid system, is converted into electrical power through a combination of a solar collector, a tracking device to maintain proper orientation with the sun and a Rankine cycle engine driving an electrical power generator. Excess electricity is utilized to produce hydrogen for storage through electrolysis of water. At the solar down time, the stored hydrogen can be used to produce high‐quality steam in an aphodid burner to operate a turbine and with a field modulated generator to supplement electric power. Case studies are carried out on the optimum configuration of the hybrid system satisfying the energy demand. A numerical example based on the actual measured solar input is also included to demonstrate the design potential. Copyright © 2001 John Wiley & Sons, Ltd.     

A review of principle and sun-tracking methods for maximizing solar systems output

Finding energy sources to satisfy the world's growing demand is one of society's foremost challenges for the next half-century. The challenge in converting sunlight to electricity via photovoltaic solar cells is dramatically reducing $/watt of delivered solar electricity. In this context the sun trackers are such devices for efficiency improvement.The diurnal and seasonal movement of earth affects the radiation intensity on the solar systems. Sun-trackers move the solar systems to compensate for these motions, keeping the best orientation relative to the sun. Although using sun-tracker is not essential, its use can boost the collected energy 10–100% in different periods of time and geographical conditions. However, it is not recommended to use tracking system for small solar panels because of high energy losses in the driving systems. It is found that the power consumption by tracking device is 2–3% of the increased energy.In this paper different types of sun-tracking systems are reviewed and their cons and pros are discussed. The most efficient and popular sun-tracking device was found to be in the form of polar-axis and azimuth/elevation types.     

Experimental investigation of high temperature congregating energy solar stove with sun light funnel

A solar stove which uses a light funnel to guide light and congregate solar energy has been designed. Its structure and operation principle have been introduced. The performance tests under the real weather have been carried out and the graphic lines of experiment have been given. The experimental result shows that the maximum temperature inside the stove is as high as 250 °C under the condition of 1.5 m² of lighting area, 70% reflectivity of reflecting aluminum foil inside surface of concentrator and no load (without water inside the coil pipe). When reflectivity is 86% the heat collecting efficiency of the device is about 43%. The collecting power that the stove receives can be up to 500 W. It is an ideal medium and high temperature solar energy congregating device suitable for industrial usage or cooking and other domestic usage.     

Fabrication of portable solar thermal bank for indoor cooking

The aim of this report is to build a portable solar thermal bank based on a Scheffler reflector that is capable of boiling-type cooking using HITEC as a thermal storage material. This report reviews the problems related to solar cooking and evaluates the novel layout of a portable solar thermal bank which includes a daily thermal storage vessel. This stove is in the shape of a cylindrical container filled with phase-changing latent heat storage material. Inside the container, we provide a small gap taking into account the volumetric expansion of the phase change material (PCM) during the melting process. The solar thermal bank is charged in the sun. It is placed directly for a few hours under the focus of a Scheffler reflector, which charges the solar thermal bank with enough thermal energy stored. After a while, the cooking process can be completed by users using that stored heat. The top cavity is used as a cooking pot in a solar thermal bank. Cooking meals do not require direct sunlight, which is typical for most solar cookers. The portable solar thermal bank is an alternative for low-income households and adapts to local traditions of indoor cooking. It is portable and can be used safely to cook indoors or outdoors. In this study, a solar cooker with a thermal storage device was developed using a PCM. The size of the stove has been calculated by calculating the energy consumption for two to three people. HITEC salt has been chosen as a phase change material for thermal storage, which will be used for cooking when there is no sunlight. It enhances the applicability of solar cooking and preserves cooking possibilities using energy stored throughout the day at low production costs.     

不同容量和地区下光煤混合发电变工况性能研究

在构建系统集成模型的基础上,阐述光煤混合发电系统变工况性能计算方法。以3个地区和4种容量燃煤机组为例,研究集成模型、取代份额、辐射强度、地区和容量对光煤混合发电系统性能的影响规律。结果表明:机组容量和地区一定的情况下,全部取代1级抽汽且辐射强度最大时的系统节能效果最优;同机组不同地区开展混合发电时,太阳能资源丰富地的集热场面积最小,集热场换热效率和太阳能热电转换效率最大,年累计节能减排量大,静态投资回收期最短;同地区不同容量机组开展混合发电时,大容量机组年平均太阳能热电转换效率和年累计节能减排量最大,静态投资回收期最短。     

Development and performance analysis of a two‐axis solar tracker for concentrated photovoltaics

This study presents a two‐axis solar tracking system equipped with a small concentrator module for electricity generation through a multijunction solar cell. The system can accurately track the sun without the need of calibration for an extended period and operate as a stand‐alone system. High‐precision solar tracking was achieved by a combination of open‐loop and closed‐loop controls. A camera tracking sensor was introduced as a feedback device in closed‐loop control. Two different types of solar concentrator modules were designed and fabricated. Their concentration ratios were analyzed against solar tracking errors by means of ray tracing software. One is made up of a paraboloidal primary concentrator and a paraboloidal secondary reflector, whereas the other has a paraboloidal primary concentrator and a hyperboloidal secondary reflector. Both modules showed an almost identical concentration ratio of 610 provided that the solar tracker is pointing perfectly at the sun. However, their performance differs considerably when tracking error is present. The maximum power output was obtained near solar noon with multijunction cells, whose average solar conversion efficiency was 21%, much higher than that of conventional photovoltaic systems. Copyright © 2015 John Wiley & Sons, Ltd.     

Design of a new three-degree of freedom spherical motor for photovoltaic-tracking systems

Photovoltaic (PV) panels directly convert the solar energy to electrical energy. The amount of electrical energy converted by PV panels mainly depends on incident solar radiation. Sun tracking systems can be used to maximize energy production since they ensure keeping the photovoltaic panels perpendicular to the incoming solar radiation. Spherical motors, which have the linear and circular movement ability in three independent dimensions, can be used for precisely tracking the sun as a solution. In this study, a spherical motor controlled by a micro-controller is designed for a PV-tracking system with the ability to move on two axes. Performance of PV-tracking system over a fixed tilted one is evaluated for the climate condition of Denizli, Turkey. The designed sun tracking system is observed to be improving this performance apparently using the output voltages obtained for one day.