太阳能光伏聚光器技术进展

介绍了太阳能聚光光伏发电系统聚光器的分类、研究现状及国内外光伏聚光器的技术研究进展,指出了光伏聚光器研究中的难点,提出了光伏聚光器的发展方向,并对其发展前景进行了展望.     

光伏聚光器的研究现状及发展趋势

介绍了聚光光伏系统降低发电成本的原理和光伏聚光器的研究现状。总结了光伏聚光器的分类方法和工作原理,并详细介绍了几种混合聚光器的性能特点。讨论了设计光伏聚光器时需要考虑的因素。最后介绍了新型聚光器的工作原理和特点,分析了光伏聚光器的发展趋势。     

蝶式光伏发电聚光器的研制

通过跟踪聚光的方法,增加太阳光伏电池板的光照强度,使得同样数量的光伏电池板产生更多电能,并大幅度降低光伏发电系统的成本。介绍了一种自动跟踪太阳的蝶式光伏发电聚光器及其聚光参数优化过程,在保证聚光器的机械强度时得到了最佳聚光比。     

聚光型太阳能光伏光热系统研究进展

聚光型太阳能光伏光热系统(CPV/T)在传统光伏发电系统的基础上增加了聚光系统和光热系统,在通过聚光系统提高光伏效率的同时将系统中多余的热量加以利用,以达到太阳能最大化利用的目的。本文介绍了CPV/T系统的工作原理及其能效影响因素,以直接影响系统太阳能综合利用效率的聚光器技术、光伏电池技术和光伏冷却技术作为分析对象,结合近几年国内外最新研究成果比较了不同类型聚光器、光伏电池以及冷却方式的优劣,列举了常见的光伏余热利用方式。分析认为:CPV/T系统虽然具有更高的太阳能利用率,但应加大对系统尤其是聚光器经济性的分析;考虑在系统中应用叠层光伏电池缓解聚光器带来的系统体积过大问题;新电池开发过程中应更注意光伏电池的温度系数以减少冷却系统的压力,冷却技术在强化散热的同时也应注意热量的收集方法及其与利用途径的有效结合。     

国内可再生能源文献信息

GN030401常规单晶硅太阳能电池在低倍聚光条件下应用研究.苑进社.太阳能学报,2003,24(2):253～257.利用常规单晶硅光伏电池,在进行输出特性研究的基础上,设计研制出带有非对称复合抛物面聚光器的光伏发电系统。该系统利用聚光器的有效聚光比随季节的变化,使光电池上接收到的太阳辐射量全年相对均衡,结果不仅降低了发电成本而且可改善系统的可靠性。GN030402季节性负载光伏方阵的倾角.杨金焕,葛亮,陈中华,等.太阳能学报,2003,24(2):241～244.朝向赤道的固定式光伏方阵最佳倾角除了取决于当地的气象和地理条件外,还与负载的性质有关。根据Ha…     

考虑太阳张角的聚光器设计北大核心CSCD

通过聚光等形式提高光能密度,减少光伏材料的使用量,有助于保护环境和节约能源。文章提出一种新型聚光器设计方案,其在分析太阳张角对光路影响基础上,对聚光器模型进行改进,并得到接收器上反射光线分布规律。根据节省材料比和聚光硅电池效率选取聚光器参数,建立聚光器三维模型,在TracePro软件中进行仿真,得到接收器表面的辐照度分布和总光通量,与传统光伏聚光器聚光效果对比,验证聚光器模型的有效性,为聚光光伏发电系统的实物设计奠定了理论基础。     

一种低倍聚光光伏系统的实验研究

提出一种拟抛物面聚光器,利用廉价的聚光器来代替电池组件,以此来降低成本。此聚光系统采用光电跟踪方法使聚光器始终正对着太阳。建立了实验系统,并通过实验分析此聚光光伏系统的性能。     

一种聚光光伏-光热耦合海水淡化系统的设计

设计了一种聚光光伏-光热(C-PV/T)耦合海水淡化系统,将常规闪蒸与多效蒸发相结合,利用C-PV/T提供海水淡化过程中海水蒸发所需的热能与动力部件所需的电能,解决了传统海水淡化过程需消耗大量常规能源及产水量相对较低的问题;并研究了光伏组件表面温度、槽式抛物面聚光器的聚光倍数、海水流量和海水的出口温度光伏组件发电功率、海水热量及淡水产量的影响。研究结果表明:在槽式抛物面聚光器的聚光倍数为40倍、海水流量为0.40 kg·s~(-1)时,海水出口温度为78℃,此时系统的产水量较高且经济性好。     

资源集约化条件下水面漂浮式光伏发电系统的研究及应用

中国光伏产业蓬勃发展，巨大的光伏市场促进了光伏发电系统效率提升、系统成本下降，给技术改造创造了空间。利用泰和20 MW渔光互补光伏电站原有鱼塘水面已布置光伏组件后剩余的空间进行技术改造，增补了400 kW水面漂浮式光伏发电系统。从光伏组件布置、系统结构设计、建设成本分析等3个方面，对新增光伏发电系统分别采用水面漂浮式光伏发电系统和传统渔光互补光伏发电系统这两种方案的建设结果进行对比分析。结果表明：采用水面漂浮式光伏发电系统可减少建设成本，增加土地利用率。研究结果可为今后相似工程设计提供参考。     

聚光光伏发电国内外研究现状

从国内外聚光光伏发电技术的主要研究方向入手,分别介绍了聚光倍率、聚光器、太阳能跟踪方式、冷却与热管理系统4方面的研究现状,展望了太阳能聚光光伏技术的应用前景。     

Output variation of photovoltaic modules with environmental factors—I. The effect of spectral solar radiation on photovoltaic module output

In this study, it was investigated how changes in spectral solar radiation effects the output of photovoltaic modules. First, there was a precise examination of the seasonal changes in spectral solar radiation. Consequently, it was found that the ratio of spectral solar radiation available for solar cell utilization, to global solar radiation, changes from season to season. It varied, from 5% for polycrystalline silicon cells, to 14% for amorphous silicon cells, throughout one year. Obviously a cell made from amorphous silicon is more severely effected by seasonal variations.

Next, the seasonal changes of photovoltaic module output were examined. The output was calculated by the conventional output evaluation method using irradiance and cell temperature. This calculated value and the subsequently measured value were accumulated and the two values compared. As a result, the accumulated output of photovoltaic modules was confirmed as changing seasonally in the same way as spectral solar radiation. The output ratio of polycrystalline silicon was found to change by 4%, while that of amorphous silicon varied by 20%. Hence the seasonal variations in spectral solar radiation should be taken into account for optimum photovoltaic power system design.     

CPC内聚光式热管集热管温度特性研究

为提高太阳能热水系统的输出温度,将CPC聚光技术应用于热管式真空集热管中,开发了一种新型的CPC内聚光式热管集热管。对该集热管建立数学模型,模拟计算其传热过程,获得了导热肋片温度、热管冷凝段温度等参数随太阳辐射强度的变化规律,并通过试验验证了数学模型的可靠性;与常规热管式真空管集热管传热特性相对比,证实了该集热管可大幅提高太阳能热水器输出温度。     

Sliver cells in thermophotovoltaic systems

Previous modelling has indicated that silicon solar cells should be thinner than 100 μm to be optimal for use in thermophotovoltaic (TPV) systems. Sliver cells are a novel type of thin photovoltaic cells fabricated from single crystal semiconductor wafers, with their contacts at the edges of the cell. A computational model was constructed to examine and compare the performance of silicon sliver cells with silicon conventional back-contact cells in TPV systems. Within the range of parameters investigated it was found that the lateral carrier transport resistance of sliver cell geometries limits their power output relative to conventional cells in TPV systems. In practical systems, the efficiencies are comparable.     

Annual performance of building-integrated photovoltaic/water-heating system for warm climate application

A building-integrated photovoltaic/water-heating (BiPVW) system is able to generate higher energy output per unit collector area than the conventional solar systems. Through computer simulation with energy models developed for this integrative solar system in Hong Kong, the results showed that the photovoltaic/water-heating (PVW) system is having much economical advantages over the conventional photovoltaic (PV) installation. The system thermal performance under natural water circulation was found better than the pump-circulation mode. For a specific BiPVW system at a vertical wall of a fully air-conditioned building and with collectors equipped with flat-box-type thermal absorber and polycrystalline silicon cells, the year-round thermal and cell conversion efficiencies were found respectively 37.5% and 9.39% under typical Hong Kong weather conditions. The overall heat transmission through the PVW wall is reduced to 38% of the normal building facade. When serving as a water pre-heating system, the economical payback period was estimated around 14 years. This greatly enhances the PV market opportunities.     

An evaluation on thermal performance of CPC solar collector

The main objective of this work is the investigation and improvement of thermal performance of evacuated CPC (Compound Parabolic Concentrator) solar collector with a cylindrical absorber. Modified types of this solar collector are always combined with the evacuated glass envelop or tracking system. The conventional stationary CPC solar collector has been compared with the single axis tracking CPC solar collector in outlet temperature, net heat flux onto the absorber and thermal efficiency. Numerical model has been analyzed based on the irradiation determined actually and the results have been calculated to predict the thermal efficiency. Based on the comparison of the measured and calculated results, it is concluded that the numerical model can accurately estimate the performance of solar collectors. The result shows the thermal efficiency of the tracking CPC solar collector is more stable and about 14.9% higher than that of the stationary CPC solar collector.     

Performance simulation for bifacial silicon solar cells

An exact analytical performance simulation program for designing recent advanced bifacial silicon solar cells has been developed. The simulated performances showed an exact consistency with that of PC-1D for conventional cell structures. The simulated internal quantum efficiency for the bifacial cell structure showed high values in longer wavelength for the cell with shorter carrier lifetime and the performance with additional rear irradiation revealed bifacial cell structures gives a higher output power for the cells with short diffusion lengths.     

Design strategy and development of spherical silicon solar cell with semi-concentration reflector system

Structural and economical merits of a spherical silicon solar cell with semi-concentration reflector system have been discussed. The roles of the reflector system have been clarified; the reflector improves short-circuit current density and also open-circuit voltage by 4–6 times concentration to make a light irradiation area comparable to a p–n junction area. We have theoretically demonstrated that the spherical Si solar cell with semi-concentration reflector system can realize a performance comparable to that of conventional Si solar cells, with less amount of silicon material use.     

Performance study of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal system

The performances of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal (TCPV/T) system have been studied via both experiment and theoretical calculation. The I–V characteristics of the solar cell arrays and the output performances of the TCPV/T system demonstrated that among the investigated four types of solar cell arrays, the triple junction GaAs cells possessed good performance characteristics and the polysilicon cells exhibited poor performance characteristics under concentrating conditions. The optimum concentration ratios for the single crystalline silicon cell, the Super cells and the GaAs cells were also studied by experiments. The optimum concentration ratios for the single crystalline silicon cells and Super cells were 4.23 and 8.46 respectively, and the triple junction GaAs cells could work well at higher concentration ratio. Besides, some theoretical calculations and experiments were performed to explore the influences of the series resistances and the working temperature. When the series resistances R_s changed from 0 Ω to 1 Ω, the maximum power P_m of the single crystalline silicon, the polycrystalline silicon, the Super cell and the GaAs cell arrays decreased by 67.78%, 74.93%, 77.30% and 58.07% respectively. When the cell temperature increased by 1 K, the short circuit current of the four types of solar cell arrays decreased by 0.11818 A, 0.05364 A, 0.01387 A and 0.00215 A respectively. The research results demonstrated that the output performance of the solar cell arrays with lower series resistance was better and the working temperature had a negative impact on the current under concentration. In addition, solar irradiation intensity had certain effects on the solar cell’s performance. For the crystalline silicon solar cell arrays, when the solar direct radiation exceeded a certain value, the I–V curves almost became a straight line and the output performances decreased due to the high series resistance leading to the high power loss. For the triple junction GaAs solar cell array, its performance was always excellent.     

Performance analysis of a hybrid photovoltaic/thermal (PV/T) collector with integrated CPC troughs

In the present investigation a theoretical analysis has been presented for the modelling of thermal and electrical processes of a hybrid PV/T air heating collector coupled with a compound parabolic concentrator (CPC). In this design, several CPC troughs are combined in a single PV/T collector panel. The absorber of the hybrid PV/T collector under investigation consists of an array of solar cells for generation of electricity, while collector fluid circulating past the absorber provides useful thermal energy as in a conventional flat plate collector. In the analysis, it is assumed that solar cell efficiency can be represented by a linear decreasing function of its temperature. Energy balance equations have been developed for the various components of the system. Based on the developed analysis, both thermal and electrical performance of the system as a function of system design parameters are presented and discussed. Results have been presented to compare the performance of hybrid PV/T collector coupled with and without CPC. Copyright © 1999 John Wiley & Sons, Ltd.     

Design and analysis of solar thermoelectric power generation system

This article reports on the design and performance analysis of a solar thermoelectric power generation plant (STEPG). The system considers both truncated compound parabolic collectors (CPCs) with a flat receiver and conventional flat-plate collectors, thermoelectric (TE) cooling and power generator modules and appropriate connecting pipes and control devices. The design tool uses TRNSYS IIsibat-15 program with a new component we developed for the TE modules. The main input data of the system are the specifications of TE module, the maximum hot side temperature of TE modules, and the desired power output. Examples of the design using truncated CPC and flat-plate collectors are reported and discussed for various slope angle and half-acceptance angle of CPC. To minimize system cost, seasonal adjustment of the slope angle between 0° and 30° was considered, which could give relatively high power output under Bangkok ambient condition. Two small-scale STEPGs were built. One of them uses electrical heater, whereas the other used a CPC with locally made aluminum foil reflector. Measured data showed reasonable agreement with the model outputs. TE cooling modules were found to be more appropriate. Therefore, the TRNSYS software and the developed TE component offer an extremely powerful tool for the design and performance analysis of STEPG plant.