Query: Challenges in the design of concentrator photovoltaic (CPV) modules to achieve hig

Candidate papers:

abstract: Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi junction solar cells. The highest CPV module efficiency achieved is 38.9% This CPV module uses four junction III V based solar cells. Moreover, mini modules have already achieved an efficiency of 43.4% The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the different components and the most important effects regarding the module design. Furthermore, we present the module designs that have shown the highest efficiencies.Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi junction solar cells. The highest CPV module efficiency achieved is 38.9% This CPV module uses four junction III V based solar cells. Moreover, mini modules have already achieved an efficiency of 43.4% The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the differen.
author_names: Maike Wiesenfarth

Ignacio Anton

Andreas W Bett
title: Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies
year: 2018

abstract: The world's oldest, and still functional, Concentrator Photovoltaic (CPV) power plant originally rated at 350 kW, and is situated 50 km from Riyadh, Saudi Arabia. There are ongoing efforts to retrofit the modules with new secondary optics and triple junction cell devices. The paper characterizes the initial optical train, whose design is non conventional in its use of a two area primary Fresnel lens. The first generation of a retrofit receiver package is described. Challenges beyond the optical design are encountered, including tracking and structural mechanics.The world's oldest, and still functional, Concentrator Photovoltaic (CPV) power plant originally rated at 350 kW, and is situated 50 km from Riyadh, Saudi Arabia. There are ongoing efforts to retrofit the modules with new secondary optics and triple junction cell devices. The paper characterizes the initial optical train, whose design is non conventional in its use of a two area primary Fresnel lens. The first generation of a retrofit receiver package is described. Challenges beyond the optical design are encountered, including tracking and structural mechanics.
author_names: Hussameldin I Khonkar

Fahad Radhi Alharbi

Abdulaziz Alyahyah

David C Miller

R K Leutz
title: Optical element design for the retrofit of the world's first concentrator photovoltaic (CPV) power plant
year: 2019

abstract: Abstract Dense array concentrator photovoltaic (DA CPV) system is facing large mismatch losses due to the highly concentrated non uniform radiation. In this paper, a novel rotational symmetry (RS) connection approach with two examples is proposed to reduce mismatch losses. The output performances of the two RS connections are compared with that of four conventional connections by using a two stage simulation method. The results indicate that under different illumination distributions and CPV cell's series resistances, the RS connection approach can dramatically reduce power losses. The proposed dichotomic rotational symmetry (DRS) and quartered rotational symmetry (QRS) connections can significantly improve the output characteristics of DA CPV modules. Compared with the conventional series parallel (SP) connections, the DRS and QRS connections can improve the conversion efficiency by at most 48% and 64.3% respectively. Meanwhile, the QRS connection exhibits smoother I V and P V curves, reducing the difficulty of system's maximum power point tracking (MPPT) and improving the stability of output performance with varying Gaussian illuminations. When considering the Joule heat losses generated from the series resistance of CPV cells, the RS connections can also achieve much higher conversion efficiencies than other conventional configurations.
author_names: Xinyu Pan

Xing Ju

Chao Chen Xu

Xiaoze Du

Yongping Yang
title: A novel rotational symmetry (RS) connection approach for dense array concentrator photovoltaic (DA CPV) modules
venue: Energy Conversion and Management
year: 2019

abstract: Abstract A new configuration of a photovoltaic module and a solar thermoelectric generator in a hybrid system integrated with a microchannel heat sink has been developed. The photovoltaic module and the solar thermoelectric generator sandwich the microchannel heat sink, as they are exposed to concentrated solar radiation. This newly developed hybrid system is compared to that with a conventional configuration in which an ordinary thermoelectric generator is attached directly to the rear surface of the concentrator photovoltaic module. To evaluate the performance of the new system in comparison to the conventional one, an all inclusive three dimensional thermo fluid thermoelectric model has been developed. This model is numerically simulated and is validated with both experimental and numerical results. The findings of this study show that the new system generates more output power and can be operated at higher concentration ratios with even lower average solar cell temperatures than the conventional system. In the new configuration, the average solar cell temperature is approximately 77 degC and the total electrical output power is approximately 3.2 kW/m2 at a solar concentration ratio of 20 suns. However, the maximum possible working concentration ratio for the conventional design is 10 suns, where the solar cell temperature approaches the highest tolerable temperature of approximately 90 degC. Moreover, the total electrical output power is approximately 1.2 kW/m2. Furthermore, it is found that at CR_PV 20, the rate of the produced thermal energy is approximately 12 kW/m2, for the conventional design while the new design achieves 15, 22, and 30 kW/m2 for CR_STEG of 1, 10, and 20, respectively. These findings have greatly aided in identifying a new design that achieves the highest performance under concentrated solar irradiance.
author_names: Ahmed Abdo

Shinichi Ookawara
title: Performance evaluation of a new design of concentrator photovoltaic and solar thermoelectric generator hybrid system
venue: Energy Conversion and Management
year: 2019

abstract: In this paper, we present a design and optical simulation of a novel linear Fresnel lens. The lens can be applied to a concentrator photovoltaic (CPV) system as a primary optical element (POE) to increase the concentration ratio and improve the uniformity of irradiance distribution over the receiver. In addition, the CPV system can use the proposed lens as a concentrator without involving a secondary optical element (SOE) The designed lens, which is a combination of two linear Fresnel lenses placed perpendicular to each other, can collect and distribute the direct sunlight on two dimensions. The lens is first designed in the MATLAB program, based on the edge ray theorem, Snell's law, and the conservation of the optical path length, and then drawn in three dimensions (3D) by using LightToolsTM. Furthermore, in order to optimize the structure and investigate the performance of the lens, the ray tracing and the simulation are also performed in LightToolsTM. The results show that the newly designed lens can achieve a high concentration ratio of 576 times, a high optical efficiency of 82.4% an acceptable tolerance of 0.84deg, and high uniform irradiance of around 77% for both horizontal and vertical investigation lines over the receiver.
author_names: Thanh Tuan Pham

Ngoc Hai Vu

Seoyong Shin
title: Novel Design of Primary Optical Elements Based on a Linear Fresnel Lens for Concentrator Photovoltaic Technology
venue: Energies
year: 2019

abstract: Concentrator Photovoltaic Thermoelectric (CPV TE) hybrid devices have the potential to address areas of limitation within concentrator photovoltaic devices, using the inherent flexibility and controllability of thermoelectrics. In this work, a full CPV TE module was designed and fabricated using commercial Primary and Secondary Optical Elements (POEs and SOEs respectively) The SOE CPV TE hybrid receivers were characterized prior to integration within the module, and connected into a string of three receivers. The acceptance angle of the POE SOE CPV TE hybrid module was experimentally characterized, and outdoor on tracker data was obtained at the University of Jaen. For the first time, the performance of CPV TE hybrid devices was evaluated within a 3 receiver string, and the efficiency of on sun TE cooling was investigated.A preliminary break even point was found at 0.3A, for active cooling verses non cooling for the CPV TE hybrid receivers. This highlights the future on sun performance increases possible with further optimised CPV TE module designs, including a low power regime for optimised TE operation.
author_names: Matthew Rolley

Tracy K N Sweet

Luka Eerens

Juan P Ferrer-Rodriguez

Eduardo F Fernandez
title: Experimental comparison of a III:V triple junction concentrator photovoltaic thermoelectric (CPV TE) hybrid module with commercial CPV and flat plate silicon modules
year: 2018

abstract: This paper addresses the necessary procedures that need to be considered when designing an optical sub system of low concentrator photovoltaic (LCPV) module. CPV systems make use of optical elements and solar tracking to concentrate solar flux onto a photovoltaic (PV) receiver. The performance of a concentrator module is highly dependent on the configuration and alignment of the optical elements in the system. In this study, various design considerations were taken into account to construct a LCPV module that was characterised with respect to optical design and electrical performance.
author_names: M A Benecke

E Ernest van Dyk

F J Vorster
title: Optical design of low concentrator photovoltaic modules
year: 2013

abstract: Despite its highest efficiency, concentrated photovoltaic (CPV) technology is still finding its way into the current photovoltaic market which is saturated with conventional flat plate photovoltaic systems. CPV systems have a great performance potential as they utilize third generation multi junction solar cells. In the CPV system, the main aspect is its concentrating assembly design which affects not only its overall performance but also its operation and fabrication. Conventional CPV design targets to use individual solar concentrator for each solar cell. The main motivation of this chapter is to propose a novel concentrating assembly design for CPV that is able to handle multiple solar cells, without affecting their size, using single solar concentrator. Such proposed design, named as multicell concentrating assembly (MCA) will not only reduce the assembly efforts during CPV module fabrication, but it will also lower the overall system cost with simplified design. In this chapter, a detailed design methodology of multicell concentrating assembly (MCA) for CPV module is presented and developed with complete verification through ray tracing simulation and field experimentation.
author_names: Muhammad Burhan

Muhammad Wakil Shahzad

Kim ChoonNg
title: Multicell Design for Concentrated Photovoltaic (CPV) Module
year: 2018

abstract: Concentration photovoltaic (CPV) modules promise a more efficient, higher power output than traditional photovoltaic modules. This is achieved by concentrating sunlight onto a small 1 cm2 concentrator triple junction (CTJ) InGaP/InGaAs/Ge cell by using high quality precision optics. In order to achieve high energy performance and reliability, well thought out design decisions must be made in the development of a CPV module. This paper investigates the design of two CPV modules (Module I and II) which are based on the Sandia III Baseline Fresnel module. The investigation concentrated on the effect of the optimization of the optical design on the electrical performance characteristics of CTJ cells with good thermal dissipation. The best performance achieved by Module I was at 336 times operational concentration (Xo) which produced a Pmax of 10.29 W per cell, with cell and module efficiencies of 39% and 24% respectively. In the development of the second module (Module II) pre deployment criteria such as the CTJ cell and system components characteristics was used to eliminate faulty components from the system what was observed in Module I. Cell units that were optimized in Module II showed no form of degradation in their Current Voltage (I V) characteristics. The cell unit operating under optical misalignment showed a progressive degradation with long term operation in the field.
author_names: R D Schultz

E Ernest van Dyk

F J Vorster
title: The optical design and performance of a concentrator photovoltaic module
year: 2017

abstract: The constant progress of the efficiency values of the multijunction (MJ) solar cells based on III V semiconductors, used together with photovoltaic concentration (CPV) technologies, means that competitive costs can be achieved generating solar photovoltaic energy, since with concentration a cell's area is reduced, being substituted by optical elements of a lower cost. The present thesis collects a series of contributions at different levels that affect CPV systems. The largest part is dedicated to the impact of solar spectrum on these systems based on MJ cells, specifically to the understanding of that effect on MJ cells and CPV systems. Firstly the spectral matching ratio (SMR) concept is reviewed, an index based on the currents of a set of component cells (isotypes) that is used to estimate which subcell of a MJ cell limits, and its use is extended to MJ cell calibration with the role of spectral index. In particular, through instants filtering using SMR baseline values, prevailing spectral conditions are established with regard to reference spectrum (ASTM AM1.5D G173 03) Based on those component cell currents the so called equivalent irradiances are defined, with which is possible to estimate the losses due to spectrum (spectral efficiency) when they are compared to the corresponding direct irradiance (DNI) Finally a study about the spectral bias when calibrating is presented, in particular the effect due to the tolerance associated with the SMR filters and the contribution due to spectral mismatch when using component cells of different technology to the MJ cell. The second contribution about spectrum is a study of the spectral classification based on SMR indexes from several locations around the world for several MJ cell technologies: lattice matched based on germanium and dilute nitrides and metamorphic, both upright and inverted. In this way relations can be established among types of locations defined by their geography and climate and spectral clusters useful for MJ cell ad hoc design. An estimation of losses due to spectral variation for each MJ technology for each location is also given. In the last contribution related to spectrum a possibility for SMRs as spectral indexes is looked at closely, previously establishing the minimum number of parameters needed to estimate the uniqueness of solar spectra. It is concluded that a single spectral index is clearly insufficient to establish spectral uniqueness and that three independent indexes are close to the biunivocal spectral identification. Based on this idea the use of SMR to establish correlations among different MJ cell technologies and other devices is suggested. Following on, a review of the factors that affect the energetic production of a CPV plant is given, and how these factors are modeled in the software photovoltaic (PV) tools that add simulation modules for CPV. Particular emphasis is placed on those factors that, influenced by the way PV systems are modeled, cause errors or present a lack of precision when the same approaches are used in CPV and recommendations and used limitations are proposed. All this is applied to an experimental 50 kW CPV plant in the NGCPV European Japan project and its energy production for two years is compared with the models of integrated power and annual energy forecast. Finally, a hybrid CPV design with lighting is proposed as part of the Spanish project LUZ CPV, where concentration, in addition to generating photovoltaic electricity, is used to transport sunlight directly for indoor illumination. In principle the hybrid concept allows an efficiency improvement of a CPV system used to illuminate by means of electrical luminary, since the transmission of sunlight is direct without energy transformation. A study about the design limitations has been performed, a full prototype has been developed and both CPV and lighting parts have been characterized. To conclude, several light guide materials have been studied to estimate the viability of the concept. RESUMEN El avance constante de los valores de eficiencia de las celulas solares multiunion (MJ) basadas en semiconductores III V permite que utilizadas junto con tecnologias de concentracion fotovoltaica (CPV) puedan alcanzarse costes competitivos en la generacion de energia solar fotovoltaica, ya que al concentrar se reduce el area de celula necesaria siendo sustituida por elementos opticos de mucho menor coste. La presente tesis recoge una serie de contribuciones a distintos niveles que afectan a los sistemas CPV. La mayor parte esta dedicada al impacto del espectro solar sobre dichos sistemas basados en celulas MJ, en concreto al entendimiento de dicho efecto sobre celulas MJ y sistemas CPV. Primero se revisa el concepto de spectral matching ratio (SMR) un indice basado en las corrientes de un set de celulas componentes (isotypes) que es utilizado para estimar que subcelula de una celula MJ limita, y se extiende su uso a calibracion de celulas MJ utilizandolo como indice espectral. En concreto, mediante el filtrado de instantes utilizando valores SMR de referencia, se establecen las condiciones espectrales prevalentes con respecto el espectro de referencia (ASTM AM1.5D G173 03) Basandose en las mismas corrientes de las celulas componentes se definen la correspondientes irradiancias equivalentes, con las que se puede estimar la perdida debida al espectro (eficiencia espectral) al comparar con el valor de irradiacion directa (DNI) correspondiente. Finalmente se ha estudiado la aparicion de sesgos en la calibracion espectral, en concreto el efecto de la tolerancia asociada a los filtros SMR y la contribucion por desajuste espectral al utilizar celulas componente de distinta tecnologia que la celula MJ. La segunda contribucion sobre el espectro trata de un estudio sobre la clasificacion espectral basadas en indices SMRs de diversas localidades alrededor del mundo para diversas tecnologias de celula MJ: ajustadas en red basadas en germanio y nitruros y metamorficas tanto rectas como invertidas. De esta forma se establecen relaciones entre tipos de localidades definidas por su geografia y clima y se pueden identificar clusteres espectrales utiles para el diseno ad hoc de celulas MJ. Tambien se estiman las perdidas por variacion espectral asociadas a cada tecnologia MJ para cada localidad. Como ultima contribucion relacionada con el espectro se profundizan las posibilidades de los SMRs como indices espectrales, estableciendo previamente el numero minimo de parametros necesarios para estimar unicidad de los espectros solares. Se concluye que un solo indice espectral es claramente insuficiente para establecer unicidad espectral y que tres indices independientes se acercan bastante a una identificacion espectral biunivoca. Basado en ello se sugiere utilizar los SMR para establecer correlaciones entre diferentes tecnologias de celula MJ y otros dispositivos. A continuacion se da una revision de los factores que afectan a la produccion energetica de una planta CPV y como se modelan en las herramientas software de fotovoltaica (PV) que incorporan componentes para simulacion CPV. Se hace especial hincapie en aquellos factores que, influenciados por la forma de modelar sistemas PV, ocasionan errores o falta precision cuando se utilizan las mismas aproximaciones sobre sistemas CPV y se proponen recomendaciones y limitaciones de uso. Todo ello es aplicado a una planta CPV experimental de 50 kW dentro del proyecto europeo con Japon NGCPV y se compara el modelado con la produccion durante dos anos, a nivel de potencia y de energia anual estimada. Por ultimo, se propone un diseno CPV hibrido con iluminacion bajo el proyecto nacional espanol LUZ CPV en el que se hace uso de la concentracion ademas de para la generacion fotovoltaica de electricidad, para el transporte directo de luz solar con el fin de iluminar interiores. El concepto hibrido permite en principio mejorar la eficiencia de un sistema CPV que se utilice para iluminar mediante una luminaria electrica, ya que la transmision de luz es directa sin necesidad de transformacion energetica. Se ha hecho un estudio para ver las limitaciones de diseno, se ha desarrollado un prototipo completo y se ha caracterizado tanto la parte CPV como la de iluminacion. Para finalizar se han estudiado diversos materiales utilizados como guia optica para estimar la viabilidad del concepto.
author_names: Ruben Nunez Judez
title: Contributions to characterization, modeling and design of concentrator photovoltaic systems
year: 2016