太阳能热气流发电系统的热力性能分析

对太阳能热气流发电系统的热力学性能进行了分析,建立了系统的热力学循环,进一步分析了系统的实际循环效率和理想循环效率,对不同规模的太阳能热气流发电系统的热力学特性进行了计算比较.结果表明:大规模太阳能热气流发电系统相应的标准布雷顿循环效率、理想循环效率以及实际循环效率分别为:35%,10%～25%和0.9%～2.0%.分析结果为太阳能热气流发电技术的设计与商业应用提供理论参考.     

一种新型的太阳能发电技术

对迄今为止有关太阳能热气流发电技术的研究成果进行了全面的综述,其中包括作者在该领域的最新研究进展：太阳能热气流发电系统的热力学循环,HAG效应,带有蓄热层的系统以及带有透平的系统耦合数值模拟等,并对下一步的研究工作进行了展望。     

太阳能烟囱与垂直轴风机耦合发电可行性分析

通过分析太阳能烟囱热气流发电和垂直轴风力机发电的技术及特点,提出了太阳能热气流烟囱与垂直轴风力机耦合发电的方法。对风力机—太阳能热气流烟囱互补发电系统的可行性进行了分析。互补发电的功率输出持续、稳定,具有大规模并网的良好条件,是实现太阳能与风能综合利用的有效途径。     

聚光式太阳能动力与制冷联合热发电系统

1前言从20世纪90年代到现在,国内外聚光式太阳能热发电系统是以聚光式太阳能锅炉取代矿物燃料锅炉,并联辅助常规能源锅炉和蓄热器进行发电的。太阳能热发电系统在热力学原理上也是按朗肯循环或勃莱顿循环运行的,而卡诺循环效率η_卡是工作于两个一定温度之间的所有热机效率η_(热机)的理论     

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。     

新型复叠有机朗肯循环太阳能热发电系统的性能分析

提出一种基于两级蓄热罐和复叠有机朗肯循环的太阳能热发电系统。该系统根据太阳辐照度的变化可在额定模式和放热模式间切换，以保证发电的稳定性和持续性。采用联苯-联苯醚同时作为集热、蓄热及顶部有机朗肯循环（ORC）的工质，苯作为底部ORC工质。对系统进行热力学优化，结果表明最大热功转化效率为38.54%，甚至比采用合成油集热、双罐熔融盐蓄热的常规热发电系统效率还高，表明所提出系统具有较好的应用前景。     

一种地热与太阳能联合发电系统研究

提出一种地热与太阳能联合发电系统,可用于地热和太阳能资源丰富的地区.该系统的特点是基于双流地热发电循环,通过增加太阳能过热器来增加系统发电量.太阳能过热环节采用槽式集热器.对异丁烷(P600a)和丁烷(R600)两种工质在不同太阳能利用分数下的发电功率和发电效率进行了比较,发现对于带有过热装置的朗肯循环(ORC),选择R600a为工质性能更佳.研究表明太阳能过热环节对于提高系统发电功率具有较大贡献,但对增加系统发电效率改善不大.还针对具有固定集热面积(1000m2)的太阳能地热发电系统应用于西藏地区可行性进行了分析,发现这种地热太阳能联合发电系统相比于常规地热发电系统,发电能力可提高约10%,对解决该地区的供电紧张状况能够起到一定的作用.     

10MW太阳能热气流发电系统结构优化与成本分析

针对太阳能热气流发电系统烟囱超高、集热棚超大的特点,基于太阳能热气流发电系统的流动与传热模型,预测了10 MW太阳能热气流发电系统的基本几何结构,建立了太阳能热气流发电系统各关键部件、整体系统的造价模型及发电成本模型.通过计算和对比10 MW系统各种几何结构型式的系统造价,获得了经济上较为合理的结构型式,并分析了影响集热棚、烟囱及系统总造价的主要因素,提出了降低系统造价的方法.结果表明,该方法经济、可行.     

太阳能热气流发电系统仿真与实验研究

太阳能热气流发电系统是一种新型的可再生能源发电系统。文章利用COMSOL Multiphysics软件构建了该系统的CFD模型,并对该系统中集热棚和烟囱内的温度和压强,以及烟囱内浮升气流的风速变化情况进行了模拟研究。同时,利用搭建的太阳能热气流实验装置测量了集热棚内气流温度和烟囱内风速,并将实验结果与仿真结果进行对比分析。分析结果表明,集热棚内气流温度和烟囱内风速实测值的变化趋势与仿真结果基本一致,集热棚内气流温度实测值的平均值与仿真值平均值之间的相对偏差为2.9%,烟囱内风速仿真值与实测值之间绝对偏差的平均值以及标准差分别为1.21 m/s,0.4。     

菲涅尔太阳能集热器驱动的冷热电联供系统热力性能分析

为了提高冷热电联供系统的灵活性和热力学性能,将线性菲涅尔集热器、吸收式热泵、有机朗肯循环、地源热泵相结合,提出了一种基于线性菲涅尔太阳能集热器的新型冷热电联供系统。在EES软件中建立了提议系统和参考系统的热力学模型,将提议冷热电联供系统和参考系统的性能进行比较,并分析了一些关键参数对系统性能的影响。结果表明：该系统在设计工况下,一次能源利用率可达到78.04%,太阳能发电效率为8.2%,热电比为10.13;与参考系统相比,节约了一次能源11.8%,提高了系统满足用户负荷的灵活性;夏季辐照强度每增加100 W/m²,一次能源利用率约增加0.95%,太阳能发电效率增加2.73%;在热分配比为0.2时,系统一次能源利用率最大为80.5%;热电比随着辐照强度和热分配比的增大而减小,当热分配比增大0.4时,夏季系统热电比下降了86.2%,冬季热电比下降了84.9%。     

Numerical analysis on an industrial-scaled solar updraft power plant system with ambient crosswind

Existing research indicated that the ambient crosswind (ACW) has very complex influences on the SUPPS both through the chimney outlet and collector inlet as demonstrated by numerical analysis from the Spanish prototype. But what influence exert ACW through chimney outlet and collector inlet independently on the overall performance of SUPPS is still unclear. In this research, two geometrical models are constructed for numerical simulation on industrial-scale SUPPS in the vicinity of 10 MW. In model 1, ACW acts on both chimney outlet and collector inlet; in model 2, ACW acts only on the chimney outlet. Fluid flow, heat transfer and power output performances of SUPPS are investigated and discussed. It is found that, the negative effect of ACW only occurs at the collector inlet, with cold ambient air into the collector resulting in changing of fluid distribution and deterioration of buoyant driving force, whereas the positive effect occurs at the chimney outlet, with strong ACW passing by the chimney outlet causing entrainment of buoyant airflow within the chimney outlet. To avoid deterioration and to improve the overall performance of SUPPS, effective measures can be taken to prevent ACW from entering the collector inlet and also to induce beneficial effects of high altitude strong ACW blowing across the chimney outlet.     

太阳能烟囱发电新技术

介绍了一种太阳能烟囱发电新技术。太阳光辐射透过太阳能集热棚，加热集热棚下面的地面，被加热的地面与集热棚内的空气进行热量交换，使其温度上升，被加热的空气上升并进入与集热棚中部相连的烟囱，在烟囱内上升气流推动涡轮发电机旋转、发电。整个太阳能烟囱发电技术的能量转化以及效率可以从三个部分来分析：通过集热棚太阳能转化为空气热能，通过烟囱将热能转化为动能，通过涡轮发电机将动能转化为电能。另外，总结了太阳能烟囱发电技术的优缺点，指出它是一种适合于我国西部地区的一种能源开发新途径。     

Available energy of the air in solar chimneys and the possibility of its ground-level concentration

Solar chimneys are defined as low temperature solar thermal power plants, which use the atmospheric air as a working fluid, where only one part of the thermodynamic cycle within the plant is utilized. The available work potential that atmospheric air acquires while passing through the collector has been determined and analyzed. The dependence of the work potential on the air flowing into the air collector from the heat gained inside the collector, air humidity and atmospheric pressure as a function of elevation are determined. Various collector types using dry and humid air have been analyzed. The influence of various chimney heights on the air work potential are established. The possibly higher utilization factors of the available hot air work potential without the use of high solid chimneys are discussed. It has been shown that the vortex motion flowing downstream of the turbine can be maintained under pressure and can possibly take over the role of the solid structure chimney. Thus, a part of the available energy potential acquired in the collector would be used to maintain the vortex flow in the air column above the ground-level turbine. Basic conditions for the maintenance of such a vortex flow are described and compared to the tornado phenomenon.     

蓄热介质对太阳能热风发电集热器性能的影响

分别以沙子、石子以及石子与充水黑色密封管的组合作为蓄热介质,搭建了太阳能集热器试验装置并进行了相应的试验研究,得出了不同蓄热介质的吸放热特性及其对集热器内空气进出口温差、集热器效率的影响规律.结果表明:在相同的平均辐射强度下,石子与充水黑色密封管组合集热器的蓄热性能好,且集热器空气进出口温差及集热器效率最大,为太阳能热风发电系统集热器地面蓄热材料的选用提供了依据.     

太阳能热风发电系统能量流的数值分析

根据太阳能热风发电系统的工作特点,建立其数值分析模型,对系统的能量流进行分析.以西班牙原型电厂为例进行数值模拟,探索太阳辐射强度和环境温度对系统性能的影响.将数值计算和西班牙试验数据进行了比较,结果具有良好的一致性.预测出太阳光辐射强度及环境温度和太阳能热风发电系统集热器进出口温差及由集热器出口到烟囱进口的系统转换段压差的影响关系.为太阳能热风发电系统的设计提供技术支持.     

太阳能烟囱发电装置的CFD模拟

用Fluent软件对太阳能烟囱发电装置内的气流进行了数值模拟，获得了太阳能烟囱发电装置内气流流速、温度等分布，并将温度场模拟计算值和试验检测值进行了比较。结果表明：气流在集热棚中从四周向中部汇流是一个加速的过程；从地面到烟囱，随着高度的增加温度呈递减分布。温度分布模拟与试验检测结果的规律基本相似。但由于进行了稳态假设，也存在一定差别。数值模拟结果以集热棚中心呈对称分布。然而，由于集热棚南部接收的太阳辐射大于北部，在试验检测中南边的温度明显高于北边的温度，温度的峰值向南边偏移，呈不对称分布。     

Feasibility study of a solar chimney power plant in Jordan

A solar chimney power plant system is theoretically designed for future erection in Jordan. Analytical analysis of the system is simulated by mathematical software. The actual values of solar irradiation in Jordan are used in the simulation to predict the power output of the solar chimney power plant. The output results of the maximum (inlet) values of velocity, pressure, and mass flow rate of air versus the chimney height variation are obtained. Furthermore, the electrical power output and the efficiency of chimney versus chimney height variation were determined. For a solar collector diameter of 40 m and a chimney diameter of 3.5 m, the maximum power output (85 kW) was obtained for a chimney height of 210 m.     

大型太阳能烟囱发电站热力分析与计算

利用热力学方法建立太阳能烟囱发电系统中集热棚、烟囱及风力透平的热气流能量转换过程的理论模型及求解方法.鉴于太阳能烟囱发电站的大尺寸特征,采用一维假设建立热气流传热模型,使用龙格-库塔方法对非线性能量方程进行数值求解.对集热棚直径3 600 m,烟囱高950 m,设计功率100 MW的大型太阳能烟囱发电站进行分析与计算,给出了该电站的风力透平轴功率随质量流量和太阳辐射强度变化的规律,为风力透平机组提供热力气动设计参数,为大规模开发利用太阳能提供借鉴.     

Power and efficiency optimization for combined Brayton and inverse Brayton cycles

A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, combustion inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative pressure drops associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the compressor pressure ratio of the top cycle are derived with the 11 pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the compressor inlet pressure of the bottom cycle, the air mass flow rate and the distribution of pressure losses along the flow path. It is shown that the power output has a maximum with respect to the compressor inlet pressure of the bottom cycle, the air mass flow rate or any of the overall pressure drops, and the maximized power output has an additional maximum with respect to the compressor pressure ratio of the top cycle. When the optimization is performed with the constraints of a fixed fuel flow rate and the power plant size, the power output and efficiency can be maximized again by properly allocating the fixed overall flow area among the compressor inlet of the top cycle and the turbine outlet of the bottom cycle.     

一种新型的太阳能热气流发电系统

提出了一种螺旋集热型太阳能热气流发电系统,建立了该系统的流动与传热特性数学模型.数值模拟结果表明,与西班牙太阳能热气流试验电站相比,在烟囱出口流动与传热特性参数及输出功率相同情况下,螺旋集热型太阳能热气流的集热棚半径减少了25%,占地面积减少了44%,具有较明显的经济性和商业优势.