Spectral Beam Splitting Technology Research Articles

Thermodynamic investigation of spectral splitting hybrid system integrated Cassegrain concentrator and mid/low-temperature solar thermochemical storage

The synergy of hybrid conversion and non-imaging optical concentrating technology is a promising solar energy utilization scheme. In this paper, a novel photovoltaic-thermochemical hybrid system based on Cassegrain concentrator and spectral beam splitting technology is proposed and comprehensively investigated to explore the feasibility of dish concentrator for mid/low-temperature thermochemical storage. The collimated secondary reflected optical path and the special TiO2–Na3AlF6 filter improved the high-density energy flow to be more compatible with the cascade of the PVT module and methanol steam reforming reactor. The features under typical operating conditions, optical control, and variable irradiance performance are analyzed via systematic mathematical methods, including ray tracing, energy flux calculation, energy conversion process, and system evaluation. Results indicate that the satisfactory optical efficiency of 81.1% is obtained by multi-objective optimization, while the average incident angle deviation is considered as a target. By regulating energy transfer through flow strategy, the conversion efficiency of solar products exceeds 42.4%. Meanwhile, the concentration ratio over 600 ensures a solar-exergy conversion capacity of more than 4.2% higher than reference systems under various irradiation, but the cutoff wavelength is not suitable to exceed 500 nm. In sum, the results are anticipated to contribute to improving the applicability of dish concentrators in distributed scenarios and the viability of full-spectrum solar energy absorption.

A novel non-confocal two-stage dish concentrating photovoltaic/thermal hybrid system utilizing spectral beam splitting technology: Optical and thermal performance investigations

Concentrating and spectral beam splitting technology towards the efficient utilization of full-spectrum solar energy has been widely concerned. This paper proposes a novel non-confocal two-stage parabolic dish concentrating photovoltaic/thermal (NTPD-CPVT) hybrid system which offers access to the alleviation of photovoltaic heat load and the two-stage heating of heat transfer fluid through a specially developed spectral beam splitter. The thermodynamic and optical properties of the system are analyzed via the comprehensive model including ray tracing, energy flux evaluation and photovoltaic/thermal hybrid energy evaluation. Results indicate that the satisfied spot uniformity and optical efficiency of 80.7% could be obtained by non-confocal optimization, and the NTPD-CPVT hybrid system shows stable overall energy efficiency over 20.9% under different irradiance conditions. Based on the comprehensive comparison, the introduction of a spectral beam splitter promotes the photovoltaic/thermal module efficiency and the system exergy efficiency by 17.6% and 10.2%, and effectively shortens the payback period. Furthermore, the reference values of implemental parameters such as error tolerances and heat transfer coefficients are provided to guarantee the optical and economic performance of the system. The research results support the potential of the NTPD-CPVT hybrid system in improving the cascade use of solar spectrum and guide the construction of future prototypes.

An Experimental Study on Transient Response of a Hybrid Thermoelectric–Photovoltaic System with Beam Splitter

In the current study, the electrical responses of a thermoelectric (TE) module and a photovoltaic (PV) cell are investigated in three different systems, namely, a PV-only system, TE-only system, and hybrid TE-PV system with a beam splitter (TE-PV-BS), under variable solar irradiations demonstrating partly cloudy weather conditions. To enhance the deployment of solar energy, a predesigned beam splitter combined with the amorphous silicon TE and PV system is used in the experiments. The impact of the spectral beam splitting technology on the conversion performance of the TE module and PV cell in the hybrid system is studied and compared to the performance of the TE-only and PV-only systems. The electrical output parameters of the TE module and PV cell are obtained for the studied systems, and they are discussed in detail. The results of this work show that the power generated by the PV cell has a stepwise fluctuation similar to the variation in the concentrated solar radiation. Affected by its heat capacity, the power variation is monotonous with the TE module. The results moreover indicate that there is more power generated by the PV cell in the TE-PV-BS hybrid system than by the PV-only system. In comparison, the TE-only system produces more power than the TE module in the hybrid system. Furthermore, the TE-PV-BS hybrid system generates higher and more stable electrical power than the TE-only and PV-only systems, showing a significant advantage of the spectrum management concept.

High temperature stability and optical properties investigation of a novel ITO-Therminol 66 nanofluid for spectral splitting PV/T systems

Abstract Spectral beam splitting technology based on optical nanofluids (NFs) is a promising field of solar energy research. However, the challenges to optimize the optical properties and enhance the high temperature stability of NFs are always exist. In this study, Indium Tin Oxide (ITO) nanoparticles were selected as the research object because of the excellent optical properties. The Oleylamine-capped ITO nanoparticles were prepared by chemical reduction. A novel NF based on Therminol 66 was successfully prepared. The high temperature stability and optical properties of obtained Oil-based NFs were analyzed by the gravitational sedimentation method and spectrophotometry. Moreover, we experimentally studied the effect of single reaction condition on the morphology and Sn-doping of particles. The results indicated that, at the reaction condition of 320 °C, 5.5 h, and the In/Sn mole ratio of 90:10, the obtained nanoparticles had high monodispersity and crystallinity, and the resulting NF had good stability and dispersion. Furthermore, when tuning single reaction condition, the morphology and Sn doping of nanoparticles tended to be a regular change. However, the change of single reaction condition was not enough to obtain the ITO NFs with good stability and dispersion. The ITO NFs obtained in present study had high thermal stability, and showed different high-temperature characteristics in the Ultraviolet and visible (UV–Vis) and near infrared (NIR) regions.

Spectral Beam Splitting Technology for Photovoltaic and Concentrating Solar Thermal Hybrid Systems: A Review

As a promising technology, spectral beam splitting (SBS) technology is the research focus currently in photovoltaic and concentrating solar thermal (PV/CST) hybrid systems. Spectral splitting filters can optimally exploit the solar spectrum and reach higher conversion efficiencies of solar energy. In this paper, we provide a review of the recently published research in spectral splitting filters and summary the research details of SBS technology, including the proposed methods, types, materials, performance advantages, technical obstacles of the filters. Moreover, the paper presents the research status of the SBS technology and evaluates the prospects of various filters in PV/CST hybrid systems. This review can help the researchers and practitioners better understand the SBS technology and features of different spectral splitting filters for the PV/CST hybrid system.

Performance investigation of a hybrid photovoltaics and mid-temperature methanol thermochemistry system

This work theoretically and experimentally presents a high-efficiency solar system which integrates photovoltaic cells and methanol thermal decomposition to make full use of the full-spectrum solar energy. In this optimized system, spectral beam splitting technology is used to split the solar spectrum into several wavebands. The spectrum suitable for photovoltaic conversion is directly converted to electricity using photovoltaic cells. The rest of the spectrum is converted into chemical energy of syngas (to be stored and converted to electricity on demand) via a mid-temperature solar-thermochemical process of methanol vapor decomposition reaction. A theoretical model is established and predicts that the electrical efficiency of the hybrid system could surpass 35%. The best system electrical efficiency, that we have experimentally demonstrated, was as high as 31.18% for a concentration ratio as low as 56 and a solar thermal temperature as low as 265 °C. The comparison to existing solar systems indicates that this proposed solar system has a great potential for efficient utilization of solar energy in large scale. This work paves the way to high-efficiency and full-spectrum utilization of solar energy.

A Review on Recent Development of Cooling Technologies for Concentrated Photovoltaics (CPV) Systems

Concentrated Photovoltaics (CPV) technology, as an energy saving method which can directly generate electricity from the Sun, has attracted an ever-increasing attention with the deepening worldwide energy crisis. However, operating temperature is one of the main concerns that affect the CPV system. Excess cell temperature causes electrical conversion efficiency loss and cell lifespan decrease. Thus, reasonable cooling methods should decrease the operating temperature and balance the flare inhomogeneity. They also need to display high reliability, low power consumption, and convenient installation. This paper presented the architectural, commercial, and industrial usage of CPV system, reviewed the recent research developments of different cooling techniques of CPV systems during last few years, including the spectral beam splitting technology, cogeneration power technology, commonly used and promising cooling techniques, active and passive cooling methods. It also analysed the design considerations of the cooling methods in CPV systems, introduced the classification and basic working principles and provided a thorough compilation of different cooling techniques with their advantages, current research limitations, challenges, and possible further research directions. The aim of this work is to find the research gap and recommend feasible research direction of cooling technologies for CPV systems.

Optimization and experimentation of concentrating photovoltaic/cascaded thermoelectric generators hybrid system using spectral beam splitting technology

The concentrating photovoltaic-thermoelectric (PV-TE) hybrid system by using spectrum splitting technology had been considered to be a promising system. The IR-wavelength light, which can’t generally be converted by solar cells, can be separated from the full solar spectrum in this system and then be appropriately converted by thermoelectric generators based on Seebeck effect. The overall system efficiency might be improved due to the additional contribution of thermoelectric generation. In this paper, a prototype PV-TE hybrid system and a numerical model for the evaluation of the whole system are presented. In order to convert IR-wavelength light into electricity sufficiently, we proposed the cascaded thermoelectric module for thermoelectric generation, which consists of two individual TE stages. These are middle-temperature thermoelectric materials, CoSb3 and low-temperature thermoelectric materials, Bi2Te3 which are configured in tandem. The numerical model was established to optimize thermoelectric module geometries and the optical concentration ratio. In addition, such a novel PV/cascaded TE generators hybrid system had been constructed and experimentally researched in practical conditions. Meanwhile, the effects of the direct normal irradiation (DNI) on the temperature of the thermoelectric module and the overall output power of the hybrid system are experimentally investigated. The optimized results showed that the DNI, optical concentration ratio and the height ratio of two TE stages could significantly affect the performances of this hybrid system. The TE subsystem efficiency ηTE can reach to 8%, the PV subsystem efficiency ηPV can reach to 44%, and total hybrid system efficiency ηPV-TE can reach to 35% under the conditions that DNI = 1000 W/m2, optical concentration ratio CF = 1000, optimized height ratio of two TE stages τ = 0.6. The experimental research results revealed that output power of PV and TE subsystem could reach to 22 W and 1.9 W respectively.

Thermodynamic and optical analyses of a hybrid solar CPV/T system with high solar concentrating uniformity based on spectral beam splitting technology

A novel multi-segment mirror hybrid solar concentration photovoltaic/thermal (CPV/T) system using the spectral beam splitting technology is proposed, and its composition, working principle and structural design method are introduced in this paper. The Needle optimization method is employed to design the spectral beam splitter for the CPV/T system. The Monte Carlo Ray Tracing method is used to simulate the solar concentrating process and the results reveal that the CPV/T system can provide high uniformity of solar radiation flux density distribution on solar cells. The relationships of key structural and optical parameters of the CPV/T system are investigated. The results indicate that increasing the solar cell installation height and reducing the solar cell width can both improve the geometric concentration ratio of the CPV/T system. The sun tracking error effect analysis is carried out. The analysis results indicate that the CPV/T system has an overall optical efficiency higher than 76.3% when the sun tracking error is less than 1°. Furthermore, the thermodynamic analysis of the proposed CPV/T system is conducted and the results show that the PV conversion efficiency and overall energy efficiency of the CPV/T system are both higher than those of the CPV system under the same condition.

A biomaterial doped with LaB6 nanoparticles as photothermal media for enhancing biofilm growth and hydrogen production in photosynthetic bacteria

A novel photothermal biomaterial, designated GeO2-SiO2-Chitosan-Medium-LaB6 (GSCML), was prepared to improve photosynthetic bacteria (PSB) biofilm development and hydrogen production performance. This biomaterial employed spectral beam splitting technology to increase the overall utilization of the incident light spectrum, which LaB6 nanoparticles (NPs) mainly absorb light at approximately 380–510 and 660–780 nm and convert it into heat energy; the transmit light is around 590 nm for PSB growth. The temperature increased, and the luminous intensity of the light transmitted through the prepared biomaterial are controlled by adjusting the LaB6 NPs' content. The average biofilm growth rate and hydrogen production rate of the biofilm on the created biomaterial were 0.05 mg/cm2/day and 2.92 mmol/h/m2, which were 3.4 and 4.1 times higher than those of the glass slide, respectively. The properties of the GSCML biomaterial provide advantages for applications in immobilized cell technologies and photobioreactors.

1-D photonic crystals for photovoltaics

The paper presents the theoretical analysis of photonic structures with 1-D photonic crystals on both sides of the slab glass and the results of experimental research. Within the scope of theoretical analysis, using the 2x2 transfer matrix method, we have determined the spectral reflectivity and transmittance characteristics, and basing on the said characteristics, we have determined the influence of the number of bilayers on the maximum reflectivity and on the width of the main reflectivity peak. For the structure with four bilayers (SiO2/TiO2) we have obtained the maximum reflectivity of 0.933 for the wavelength λr = 505nm and full width at half maximum of the main reflectivity peak of FWHM=185nm.   Full Text: PDF References T.M.Razykov, C.S.Ferekides, D.Morel, E.Stefanakos, H.S.Ullal, H.M.Upadhyaya,"Solar photovoltaic electricity: Current status and future prospects", Sol. Energy 85, 1580 (2011)[CrossRef] B. Parida, S. Iniyanb, R. Goic,"A review of solar photovoltaic technologies", [CrossRef] Organic electronics, edited by Hagen Klauk, (Weinheim, WILEY-VCH Verlag GmbH & Co.KGaA,. 2006) E. Gondek, I.V.Kityk, A.Danel,"Some anthracene derivatives with N,N-dimethylamine moieties as materials for photovoltaic devices", [CrossRef] E.Gondek, Y.Djaoued, J.Robichaud, P.Karasiński, I.V.Kityk, A.Danel, K.J.Plucinski,"Influence of TiO2 nanoparticles on the photovoltaic efficiency of the ITO/PEDOT:PSS/fluorine copolymers/polythiophene: TiO2/Al architecture", J. Mater. Sci.: Mater Electron[CrossRef] R.Signerski, G.Jarosz,"Effect of buffer layers on performance of organic photovoltaic devices based on copper phthalocyanine-perylene dye heterojunction", Opto-Electron. Rev. 19, 468 (2011)[CrossRef] A.G.Imenes, D.R.Mills,"Spectral beam splitting technology for increased conversion efficiency in solar concentrating systems: a review", Sol. Energy Mater. Sol. Cells 84, 19 (2004)[CrossRef] A.Zhedi,"Review of modelling details in relation to low-concentration solar concentrating photovoltaic", Ren. Sust. Energy Rev 15, 1609 (2011)[CrossRef] B.C.Rowan, L.R.Wilson, B.S.Richards,"Advanced Material Concepts for Luminescent Solar Concentrators", [CrossRef] R.M.Almeida, L.M.Fortes, M.C.Gonçalves,"Sol–gel derived photonic bandgap coatings for solar control", Opt. Mater. 33, 1867 (2011)[CrossRef] E. Yablonovitch,"Inhibited Spontaneous Emission in Solid-State Physics and Electronics", Phys. Rev. Lett. 58, 2059 (1987)[CrossRef] G.V.Morozov, F.Placido, D.W.L.Sprung,"Absorptive photonic crystals in 1D", J. Opt. 13, 035102 (2011)[CrossRef] P.Karasiński, "Influence of aging and annealing on the properties of silica films produced with sol-gel method", Opt. Appl. 36, 389 (2006) P.Karasiński, E.Gondek, S.Drewniak, I.V.Kityk,"Nano-sized blue spectral shift in sol–gel derived mesoporous titania films", J. Sol Gel Sci. Techn. 61, 355 (2012)[CrossRef]

Concentrating PV/T Hybrid System for Simultaneous Electricity and Usable Heat Generation: A Review

Photovoltaic (PV) power generation is one of the attractive choices for efficient utilization of solar energy. Considering that the efficiency and cost of PV cells cannot be significantly improved in near future, a relatively cheap concentrator to replace part of the expensive solar cells could be used. The photovoltaic thermal hybrid system (PV/T), combining active cooling with thermal electricity and providing both electricity and usable heat, can enhance the total efficiency of the system with reduced cell area. The effect of nonuniform light distribution and the heat dissipation on the performance of concentrating PV/T was discussed. Total utilization of solar light by spectral beam splitting technology was also introduced. In the last part, we proposed an integrated compound parabolic collector (CPC) plate with low precision solar tracking, ensuring effective collection of solar light with a significantly lowered cost. With the combination of beam splitting of solar spectrum, use of film solar cell, and active liquid cooling, efficient and full spectrum conversion of solar light to electricity and heat, in a low cost way, might be realized. The paper may offer a general guide to those who are interested in the development of low cost concentrating PV/T hybrid system.

Optical modeling for a two-stage parabolic trough concentrating photovoltaic/thermal system using spectral beam splitting technology

A two-stage parabolic trough concentrating photovoltaic/thermal (PV/T) system is described, which contains a concentrator, a spectral beam splitting filter, an evacuated collector tube and the solar cell components. The nondimensional optical model with the focal length of the concentrator as the characteristic length has been developed to analyze the properties of the concentrating system using the beam splitting filter. The geometry concentration ratio and the size of solar image at different structure parameters have been obtained. Based on the ray tracing algorithms, a detailed three-dimensional model is set up to evaluate the local radiation flux density distribution on the elements’ surfaces. And the effects of the solar brightness distribution and optical errors (e.g., alignment error and tracking error) are also involved. Furthermore, the spectral distribution of the solar radiation is illustrated with the beam splitting filter, which has been specially designed using the needle optimization method. It is shown that using the filter the heat load of the cell can be reduced by 20.7%, up to 10.5% of the total incident solar energy can be recovery by the receiver, and the overall optical efficiency in theory is about 0.764.

05/02198 Spectral beam splitting technology for increased conversion efficiency in solar concentrating systems: a review

05/02198 Spectral beam splitting technology for increased conversion efficiency in solar concentrating systems: a review

Spectral beam splitting technology for increased conversion efficiency in solar concentrating systems: a review

Solar concentrating systems that employ one or more quantum receivers may realize improved energy utilization and higher electric conversion efficiency by incorporating spectral beam splitting technology. Such techniques were investigated in thermophotovoltaic conversion, introduced in the early 1960s, and in concentrating PV devices using cells of different band-gap materials, proposed as early as 1955. One major application was found in systems combining quantum and thermal receivers. This article presents a review of the various solar hybrid beam splitting systems proposed in the literature and the different spectrum splitting strategies employed.