单晶硅太阳电池在槽式聚光与普通光照条件下伏安特性的对比研究

为进一步对开发聚光热电联供系统提供依据与指导,在槽式聚光器中,设计了槽式单晶硅太阳能电池热电联供测试系统,并在太阳聚光条件下对单晶硅太阳电池进行了伏安特性的测试.测试结果表明,普通单晶硅太阳能电池在聚光10倍左右的情况下,开路电压变化不大,开路电流放大了4.1倍左右,伏安特性曲线基本满足线性关系.     

Progress in beam-down solar concentrating systems

Concentrating solar technologies are promising renewable energy systems for exploiting incident beam solar irradiation with high exergy efficiency values. These systems provide the possibility for producing useful heat at high temperatures that can be utilized by highly efficient power cycles or producing directly solar fuels with receiver reactor technology. In the last years, the concept of beam-down concentrating solar technology gains more and more attention due to a series of advantages associated with this idea. This concept is based on the use of two-stage reflectors for concentrating solar irradiation close to the ground, something that leads to a more compact system with reduced height. Furthermore, the high-temperature heat production and the chemical processes take place on the ground and not at a great height, increasing the safety levels of the system. Moreover, this design leads to compact configurations with lower materials use, lower wind loads and without the need to move the receiver for tracking the sun.The objective of this review is to present the recent progress on beam-down solar concentrating technology and to highlight the need for giving attention to this direction. Critical advantages of this technology are demonstrated and the associated limitations are discussed. The emphasis is on the presentation of the different technologies that can be coupled with the beam-down technology. Thermodynamic power cycles (Brayton, Rankine and Stirling), photovoltaics, thermochemical processes, as well as other applications are included and discussed. Practically, power production and solar fuels are the major useful outputs that can be generated by beam-down solar concentrating configurations. The reviewed technologies are critically discussed and compared in terms of energy, economic and environmental aspects. Future steps in the field are suggested based on the existing literature.     

聚焦太阳能发电与建筑一体化——我国首座太阳能发电与建筑一体化建筑保定“电谷锦江国际酒店”并网发电

<正>经过一段时间试运行,我国首座太阳能发电与建筑一体化完美结合的标志性建筑——保定"电谷锦江国际酒店",2008年10月18日正式并网发电,这也是国内首个实现建筑光伏发电并网运行的示范工程。一年多来,发电并网运行正常。     

Size-dependent behavior of polymer solar cells measured under partial illumination

We systemically investigate the size-dependent behavior of organic photovoltaics (OPVs) tested under partial illumination. An illumination mask was hypothesized to limit uncertainty associated with device size and illumination conditions when measurements are conducted on laboratory scales. Introducing the illumination mask into the measurement improves the accuracy of J_SC; however partial illumination will result in a decrease in V_OC and an increase in FF. This last observation is explained by diodes contributing both light and dark currents in the measurement. In addition to loss due to the energy required to separate bound excitons, these results suggest that non-optimized photo-dark current ratio could be another reason why measured V_OC is less than ideal V_OC.     

聚光太阳能发电的进展

上世纪80年代，美国产业界利用能源部的先进技术，建造了354MW的商业联网太阳能热电站。持续执行合作研发计划，已使太阳能热电成为世界上成本最低的太阳能发电方式。乐观的预计，10年内，太阳能热发电就能和传统发电竞争了。     

AB based solar cells and concentrating optical elements for space PV modules

This paper presents briefly the results of the development of , and GaSb cells manufactured for tandem solar cells, as well as tandems designed for point and line-focus concentrator modules. The maximum efficiency 23–23.8% (25°C, AM0) under 20–100 suns has been reached in the infrared transparent cells with prismatic cover. The efficiency 27.5% under AM1.5, 140 suns conditions has been reached as well. The bottom cells are based on lattice-matched or GaSb homo-junction Zn-diffused structures. The summation of the highest efficiencies measured in the top and bottom cells gave the values 28.8%–29.4% (AM0, 20–70 suns, 25°C) and 33.2% (AM1.5, 100 suns, 30°C). Two types of concentrator photovoltaic modules employing the reflective optical elements have been developed. The first type is based on compound parabolic concentrators, the second one on line-focus parabolic troughs. The estimated specific parameters of these modules with single-junction solar cells are the following: 230–240 W · m⁻² (AM0) and 3 kg · m⁻². The usage of tandem cells will allow to increase specific power of these modules on the value of 20–25%.     

Scaling up concentrating solar thermal technology in China

More than 1300 GW new generating capacity will be added in China's power sector over the period 2005–2030 under the BAU scenario in [1], even higher than the total installed capacity in the United States to date. China’s industrial and service sectors are expected to maintain rapid development rate over the next decades, driving up the demand for electric power and heat. However, China’s power and industrial process heat generation are heavily relying upon coal-fired thermal power plants resulting in tremendous rise in greenhouse gas emissions. Clean technology such as concentrating solar thermal (CST) needs to play a more important role in power and heat generation in China to accelerate the decarbonisation in the power sector and commercial and industrial process heat generation cost-effectively. This paper attempts to explore the opportunity and challenge of development and deployment of CST in China from both technical and socioeconomic analysis perspectives. It is argued that rapid deployment of CST in China will contribute to enabling sustainable energy supply and environmental securities, as well as improved economic performance in new technology innovation in Asia Pacific area over the next decades. Supportive policy framework should be set up to encourage scaling up CST industry. The success of deployment of CST technology will also allow Chinese power and heat generators to strengthen their competitiveness in the context of intensified global constraint of carbon emissions. Institutional innovation and policy instruments for scaling up this technology and the enabling conditions of successful implementation are also investigated.     

Mitigating the non-uniform illumination in low concentrating CPCs using structured reflectors

One problem in concentrating photovoltaic systems without active cooling is the formation of hot spots on the solar module cells. These hot spots are a result of uneven concentration of radiation within the solar module cells. The overall effect of concentrated heating is the reduction in the fill-factor of the solar module cell and the subsequent decrease in the overall efficiency of the system. In this paper, we investigate one alternative of improving the performance of a low concentrating photovoltaic system using semi-diffuse rolled reflective elements. Our results indicate that rolling marks on the reflector aligned parallel to the plane of the solar module cell improve the performance of the photovoltaic system.     

The effects of non-uniform illumination of solar cells with concentrated light

Non-uniform illumination of solar cells leads to a decrease in efficiency. Two cases were investigated experimentally: loss of power due to the shadowing of a fringe area of one cell, and loss of output of two cells which were connected in series and were illuminated to different degrees. The results show that losses due to these effects will reduce the output of concentrator photovoltaic systems working at low concentration conditions by a few per cent only.     

Performance evaluation of three solar concentrating cookers

Three solar concentrating type cookers meant for domestic use were tested for their thermal performance and cooking abilities. Stagnation temperature, water heating and cooking tests were conducted. During the tests, the operational ease and problems in each cooker were evaluated.     

Maximally concentrating collectors for solar energy applications

The performance characteristics of a solar energy collector can be described by a function relating the concentration to the direction of incident radiation. A strict bound on the integral of this function is established. This is used to define a realistic class of collectors with maximal concentration which can serve as a basis for design and optimality studies.     

Activation of dopant in the p-layer of amorphous silicon solar cells under illumination

We have investigated the effect of light-soaking on the p-doped layer of amorphous silicon (a-Si:H) solar cells by low temperature (50–300 K) AC conductance measurements. The experimental results are interpreted on the basis of an equilibration model of the doped material. The model takes into account the finite dimension of the layer and its presence inside a complex structure. It is shown that the Fermi level shifts after light soaking, which can result in activation of the doping impurities.     

The potential of concentrating solar power in South Africa

In this paper all provinces of South Africa with a good potential for the implementation of large-scale concentrating solar power plants are identified using geographic information systems. The areas are assumed suitable if they get sufficient sunshine, are close enough to transmission lines, are flat enough, their respective vegetation is not under threat and they have a suitable land use profile. Various maps are created showing the solar resource, the slope, areas with “least threatened” vegetation, proximity to transmission lines and areas suitable for the installation of large concentrating solar power plants. Assuming the installation of parabolic trough plants, it is found that the identified suitable areas could accommodate plants with a nominal capacity of 510.3 GW in the Northern Cape, 25.3 GW in the Free State, 10.5 GW in the Western Cape and 1.6 GW in the Eastern Cape, which gives a total potential nominal capacity of 547.6 GW for the whole country.     

Techno-economic evaluation of concentrating solar power generation in India

The Jawaharlal Nehru National Solar Mission (JNNSM) of the recently announced National Action Plan on Climate Change (NAPCC) by the Government of India aims to promote the development and use of solar energy for power generation and other uses with the ultimate objective of making solar competitive with fossil-based energy options. The plan includes specific goals to (a) create an enabling policy framework for the deployment of 20,000 MW of solar power by 2022; (b) create favourable conditions for solar manufacturing capability, particularly solar thermal for indigenous production and market leadership; (c) promote programmes for off grid applications, reaching 1000 MW by 2017 and 2000 MW by 2022, (d) achieve 15 million m² solar thermal collector area by 2017 and 20 million by 2022, and (e) deploy 20 million solar lighting systems for rural areas by 2022. The installed capacity of grid interactive solar power projects were 6 MW until October 2009 that is far below from their respective potential.     

The effective size of the solar cone for solar concentrating systems

In this paper we define a virtual solar cone, whose principle axis is aligned with the solar vector, having a radial angular displacement containing a pre-defined proportion of the terrestrial solar radiation. By simulating various sunshape profiles, the angular extent of the energy distribution is established to give the effective size of the solar cone for a range of atmospheric conditions. Then, by simulating the reflection of these solar distributions off a set of non-ideal mirrored surfaces, accounting for non-specular reflection and mirror shape errors, the combined effect of sunshape and mirror properties on the solar image is obtained. Clear trends are presented that show the dependence of the effective size of the solar image on the accuracy of a mirrored surface for different sunshapes. We then identify the effective size of the solar image at the absorber plane that must be accommodated in the design and optimisation of solar concentrating systems.     

太阳能热发电系列文章(1)聚光类太阳能热发电概述

能源短缺、资源枯竭、环境污染等问题已严重影响人们的生活和制约社会的发展,各国竞相开展水能、风能、地热能、生物质能、潮汐能、太阳能等清洁和可再生能源的应用研究。美国、德国、以色列、澳大利亚及日本等国家在太阳能应用技术研究方面起步较早,也是当今太     

Binary conversion cycles for concentrating solar power technology

It is recognized that the temperature potential of concentrated solar energy is much higher than needed by standard conversion cycles. High temperature solar receivers are in the development stage hopefully leading to the use of solarized gas turbines or of solar combined cycles. These systems are analyzed and taken as a reference standard. Binary alkali-metal steam cycles are shown to be intrinsically more efficient than combined cycles owing to their fully condensing nature. Even at top temperatures of about 600 °C typical for steam cycles the binary cycle allows, in principle, a significant efficiency gain (49.5% against 43% of a steam cycle). However, the binary high temperature systems are investigated featuring either a direct vaporization of the metal within the receiver or a liquid receiver cooling loop with the working fluid vaporized in a proper heat exchanger.With reference to the second option, the computed efficiency is 56% at a top cooling loop temperature of 1000 °C (the same efficiency is attained in a direct vaporization loop at 720 °C). A 60% thermal efficiency is within the potential of the technology. The above figures can be compared with a combined cycle efficiency of 50% at 1200 °C turbine inlet temperature.Available alkali metals are reviewed for the use of working fluid: potassium being the best known fluid but rubidium (or cesium) offering, in perspective, a better overall performance. Material problems connected with the containment of alkali metals at high temperature are reviewed. Experimental evidence suggests that up to 800–850 °C stainless steel is an adequate material, while for higher temperatures, up to 1200 °C, refractory metals should be used.With reference to heat storage the availability of appropriate high temperature substances either as liquids or as melting solids, storing energy as sensible or as latent heat respectively, is discussed.Finally the critical issue of metal vapour turbine design is considered. The results of a number of computations are presented giving the basic geometrical data of some potassium, rubidium and cesium expanders. Rotor diameters tend to be comparatively large. With reference to a 50 MW overall plant output the maximum tip diameter is 3.9 m for a potassium and 2.8 m for a rubidium turbine.     

Generalized analysis of the illumination intensity vs. open-circuit voltage of solar cells

A new technique to determine the current–voltage characteristics of solar cells based on simultaneously measuring the open-circuit voltage as a function of a slowly varying light intensity has been proposed recently [Sinton and Cuevas, Proc. 16th European Photovoltaic Solar Energy Conf., Glasgow, UK, May 2000, pp. 1152–1155]. This paper presents a detailed theoretical analysis and interpretation of such quasi-steady-state V_oc measurements (QssV_oc). The ability of this analysis to accurately obtain the true steady-state device characteristics even in the case of high lifetime, high resistivity devices is demonstrated experimentally. Besides reasonable choices for the light source (2 and 4 ms exponential flashes), we have also used a rapidly varying illumination (0.35 ms decay rate) to illustrate problems with the existing analysis. The new analysis results in an excellent agreement between the three QssV_oc measurements and the true steady-state and dark I–V curves. An important application of the QssV_oc technique is to determine the minority carrier lifetime, and the new model proves to be especially important to do this accurately.     

Design of concentrating elements with CIS thin-film solar cells for façade integration

A concentrating photovoltaic wall element, including Cu(In, Ga)Se₂-based modules, aluminum reflectors, and an insulation for building integration, has been developed and evaluated. The geometric concentration ratio of the system is about 3×. However, the measured maximum electric power from the modules is only 1.9 times that of identical vertical modules without reflectors, due to optical losses and a decrease in fill-factor from 0.6 to 0.5 under concentrated light. The optical efficiency of the system is 76% at an effective solar height of 40°.