太阳能光学研究与太阳能热发电产业化技术

太阳能热发电能够连续发电,是未来电力系统必不可少的技术.该项研究建立了聚光太阳能系统光学分析的通用理论,发展了聚光太阳能光学系统性能计算与优化的方法和程序;研究了主要聚光太阳能光学系统性能,提出了多种新型聚光太阳能光学系统设计.设计的点聚焦菲涅耳系统,效率与碟式系统相差无几,成本却低得多.提出的工业化技术方案,发电上网电价可降低到0.22元/kW·h,比现有火力发电方式成本低一半以上,从而提出了可行的聚光太阳能热发电产业化发展路线,为解决人类未来能源问题提供了良好的选择.

专利信息

太阳能热利用；风能利用；

Theoretical and Practical Progress of New Heliostat by Chen et al.

Recently, Chen and his team were active in the theoretical and practical study of a new heliostat for the use of solar energy. This work represents the first innovation in the area of heliostats after many years of little progress. The mathematical development of the tracking and concentration optics principles, and the practical implementation and demonstration of the technology, are both very interesting advances in this field. Many applications are possible for this technology such as generation of solar electricity and solar industrial process heat.

Electrochemical creation of surface charge transfer channels on photoanodes for efficient solar water splitting

Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO_(4) electrodes was ascribed to the removal of MoO_(x) segregations,which are considered to be surface recombination centers for photoinduced electrons and holes.However,this proposed mechanism cannot explain why activated Mo‐doped BiVO_(4) electrodes gradually lose their activity when exposed to air.In this study,based on various characterizations,it is suggested that electrochemical treatment not only removes partial MoO_(x) segregations but also initiates the formation of H_(y)MoO_(x) surface defects,which provide charge transfer channels for photogenerated holes.The charge separation of the Mo‐doped BiVO_(4) electrode was significantly enhanced by these charge transfer channels.This study offers a new insight into the electrochemical activation of Mo‐doped BiVO_(4) photoanodes,and the new concept of surface charge transfer channels,a long overlooked factor,will be valuable for the development of other(photo)electrocatalytic systems.

Characteristics of Polyaniline/Si Heterojunction Solar Cell By Electrochemical Dye Sensitization

Using the electrochemical polymerization dye sensitization(ECDS) method, polyaniline(PAn), which is used as top region material in solar cells, is sensitized with direct blue dye(DS), and sensitized Al grid/DS-PAn/n-Si/Al heterojunction solar cells is prepared by ECDS. Influences of the ECDS on the absorption spectrum and the junction characteristics of the solar cell were discussed, and the output characteristics were measured. The results show that the absorption spectrum of the sensitized PAn films is much wider and stronger in Vis-range; the diode quality factor is about 6.3 and the height of latent barrier potential of p-n junction is 0.89eV; the short-circuit current and the conversion efficiency of sensitized DS-PAn/Si heterojunction solar cells are greatly improved, which the short-circuit current can increase 6 times, the fill factor is 57% and the efficiency can reach 1.42% under the illumination of 37.2W/m^2, respectively.

Removal of SiC particles from solar grade silicon melts by imposition of high frequency magnetic field

Non-metallic particles and metallic impurities present in the feedstock affect the electrical and mechanical properties of high quality silicon which is used in critical applications such as photovoltaic solar cells and electronic devices. SiC particles strongly deteriorate the mechanical properties of photovoltaic cells and cause shunting problem. Therefore, these particles should be removed from silicon before solar cells are fabricated from this material. Separation of non-metallic particles from liquid metals by imposing an electromagnetic field was identified as an enhanced technology to produce ultra pure metals. Application of this method for removal of SiC particles from metallurgical grade silicon （MG-Si） was presented. Numerical methods based on a combination of classical models for inclusion removal and computational fluid dynamics （CFD） were developed to calculate the particle concentration and separation efficiency from the melt. In order to check efficiency of the method, several experiments were done using an induction furnace. The experimental results show that this method can be effectively applied to purifying silicon melts from the non-metallic inclusions. The results are in a good agreement with the predictions made by the model.

Effect of Substrate Temperature on Optical Characteristics of Silver Island Films for Harvesting Solar Energy

Due to their particular optical characteristics,metallic island films have the potential to significantly increase the energy conversion efficiency of solar cell.We experimentally and theoretically investigated the effect of substrate temperature on the morphologies and optical properties of the silver island films.At low temperature,below 300 ℃,as the substrate temperature increases.Compared to the films prepared at room temperature,the sizes of nanoparticles decrease and the Absorption peaks shift to shorter wavelength accompanied by an increase density resulting in a 150% Absorption efficiency.As the substrate temperature goes up to 300 ℃,nanoparticles with larger in-plan(X-Y)dimensions are formed,the number density decreases and the Absorption peaks redshift but the Absorption efficiency is still 10% higher.Numerical simulation reveals that these behaviors are a consequence of morphologies transformation.

Optical Design of a Solar Parabolic Concentrating Collector Based on Trapezoidal Reflective Petals

In this paper, detailed optical of the solar parabolic dish concentrator is presented. The system has diameter D = 2,800 mm and focal length f = 1,400 mm. The efficient conversion of solar radiation in heat at these temperature levels requires a use of concentrating solar collectors. In this paper, detailed optical design of the solar parabolic dish concentrator is presented. The parabolic dish of the solar system consists from 12 curvilinear trapezoidal reflective petals. This paper presents optical simulations of the parabolic solar concentrator unit using the ray-tracing software TracePro. The total flux on receiver and the distribution of irradiance for absorbed flux on center and periphery receiver are given. The total flux at the focal region is 4,031.3 W. The goal of this paper is to present optical design of a low-tech solar concentrator, that can be used as a potentially low-cost tool for laboratory-scale research on the medium-temperature thermal processes, cooling, industrial processes, solar cooking and polygeneration systems, etc.

Solar Photochemical Pre-Treatment for Sulphurous Ground Water Purification Process

The sulfurous water deposit exploitation in volcanic, swamp, or wetland regions, represents an alternative option for potable water supply in cities and communities around the world. However, before its consumption, it must be treated by the application of physicochemical or biological methods with the ability to separate high contents in sulfates, hydrogen sulphite and sulphides which have laxative, allergic and toxic properties in humans. Conventional methods require the supply of chemical compounds or the adequate control of different parameters such as pH, temperature, etc., and the constant maintenance within their reactors. For these reasons, the systems could have elevated operating costs and require additional steps to enable the treatment of its separated products and the final disposal of its residual waste generated. In this research, compound parabolic collectors are implemented for the use of solar energy radiation, UV-B type, in Solar Advanced Oxidation Processes in H2O2/O3/UVsolar homogeneous phase. Its application during the pre-treatment of four sulfur water wells from the region of Puebla, Mexico, demonstrated its ability to transform their sulfur compounds in sulfates of easy removal by a later stage of reverse osmosis, in an approximately 15 min treatment time process.

Study of a Parabolic Trough Adequate for the CERER Site （Dakar-Senegal）

This study presents the modeling of a parabolic trough solar collector. The main objective is to show the influences of the parabolic trough sensor effective efficiency （concentrator optical efflciencies of transmission, reflection, geometrical and the receiver absorption coefficient）, of its length, of the mass flow rate on temperatures distributions of the heat fluid and the receiver and on thermal global efficiency （solar conversion efficiency into energy usable）. The atmospheric parameters are those of Senegal in April. A prototype existing in the CERER （Center of Studies and Research on Renewable Energies） （Dakar-Senegal） is given as example of application.

Merit Figures for the Optical Design of CSP Plants

This work proposes some optical merit figures useful for solar concentration in the phase of optical design. The examined systems are CSP （concentrated solar power） plants with heliostats fields. In order to characterize them, it is suggested to use some optical merit figures, applicable to every CSP plant and synthetize its optical performance. The proposed merit figures have the aim of assessing mirrors field efficiency and receiver optical efficiency. In particular, they are identified using a new definition of the input flux on the mirrors field. The practical advantage of using the optical merit figures is illustrated by means of a simulation.

Analysis of Energy Saving Achievable through Solar Photovoltaic Systems on School Roofs： A Case of the City of Rome

Embracing renewable energy technology makes a lot of sense for the public sectors and schools as it meets the government sustainability goals and provides a financially viable means of achieving carbon savings while offering income potential. This study is aimed to quantify the achievable energy saving by spread use ofphotovoltaic systems on public building stock in the city of Rome. The installation of PV （photovoltaic） systems in the historic center depends on the feasibility conditions, generally more complex compared to the cases examined in the consolidated city, because they require compliance with the formal and aesthetic characteristics of the buildings, so the choice must be made between compatible components, which allow to minimize the transformation. The suburbs are characterized by large plane roofs in bad conditions and belonging to isolated buildings, so the useful surface, according to shading condition, offers a big potential for renewable technologies. The research provides an evaluation of maximum production of solar energy and the subsequent energy saving and reduction of greenhouse gasses, using parametric data, and an evaluation of the cost-effectiveness, with a rough calculation of return on investment.

Theoretical investigation of photoelectric properties of the four-coordinate organoboron compounds based on diketopyrrolopyrrole derivativ

In order to obtain high efficiency of organic light-emitting diodes and organic solar cells,a series of DPP-based four-coordinate organoboron compounds have been designed for photoelectric functional materials.The effects of electron-donating and-withdrawing substituent on the electronic and optical properties have been investigated by using density functional theory(DFT)and time-dependent DFT(TD-DFT)approaches systematically.It turned out that electron-donating and-withdrawing groups can tune effectively the frontier molecular orbital(FMO)energy level,energy gap,and absorption and fluorescence spectra.The introduction of electron-withdrawing groups for the parent molecule HBDPP(2,5-bis(diphenylboryl)-3,6-bis(pyridin-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione)favors the decrease for the FMO energy(E_(LUMO)and E_(HOMO)),HOMO-LUMO gaps(E_(g)),and the downhill energetic driving force(ΔEL-L),while the electron-donating groups can increase E_(LUMO),E_(HOMO),E_(g),andΔEL-L compared with that of HBDPP,respectively.The absorption and fluorescence spectra of the electron-withdrawing substituted derivatives exhibit bathochromic shifts,while the absorption and fluorescence spectra of the electrondonating substituted derivatives show hypsochromic shifts compared with the parent molecule HBDPP,respectively.Furthermore,the stronger the electron-withdrawing/donating ability of group is,the more significant the effect in the optoelectronic properties.

Enabling practical electrocatalyst-assisted photoelectro- chemical water splitting with earth abundant materials

Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting demand. Widespread utilization of solar energy faces challenges as a result of its diffusive （hence low energy density） and intermittent nature. How to effectively harvest, concentrate, store and redistribute solar energy constitutes a fundamental challenge that the scientific community needs to address. Photoelectrochemical （PEC） water splitting is a process that can directly convert solar energy into chemical energy and store it in chemical bonds, by producing hydrogen as a clean fuel source. It has received significant research attention lately. Here we provide a concise review of the key issues encountered in carrying out PEC water splitting. Our focus is on the balance of considerations such as stability, earth abundance, and efficiency. Particular attention is paid to the combination of photoelectrodes with electrocatalysts, especially on the interfaces between different components.

Perovskite thin-film solar cell: excitation in photovoltaic science

As a new member of thin-film solar cells, the perovskite solar ceils have inspired a new research hot in new photoelectric materials and devices, and have given a new energy to the photovoltaic science. Currently, various device structures, including mesoporous and planar, with and without hole transport material have been developed. In this review, much focus has been addressed to the deposition of high-quality perovskite films, structural optimization, and interface engineering as well as the understanding of the charge generation, transport, and recombination mechanisms of the devices. Furthermore, cost, stability, and environment issues of the cell are also discussed for commercial application.