High Concentration Photovoltaic Research Articles

A novel designed manifold ultrathin micro pin-fin channel for thermal management of high-concentrator photovoltaic system

To meet the requirements of cooling challenges of high concentrator photovoltaic (HCPV), a novel manifold ultrathin micro pin-fin heat sink (MUMPFHS) cooling technique is developed in this study. A comprehensive three-dimensional simulation model is established to investigate the thermal, energy and exergy performance of 10 × 10 mm2 HCPV cells cooling with MUMPFHS, using Star CCM+ with the help of user defined field functions. Compared with the previously proposed designs of the HCPV cooling schemes using jet impingement, hybrid jet impingement/microchannel and stepwise varying width microchannel, the present one shows great advantages of both uniform solar cell temperature and high cooling performance under a high solar concentration of 1000 suns. At inlet flow rate of 3 kg/h and temperature of 25 °C, the solar cell temperature can be reduced to 51 °C, with a small temperature non-uniformity of 3.4 °C. As the inlet flow rate increases, the average cell temperature and its non-uniformity further decrease, resulting in a higher electrical efficiency. However, the inlet coolant temperature has little impact on the cell temperature uniformity, allowing maximizing the inlet temperature to improve the thermal exergy efficiency under the recommended temperature range. In addition, five different designs of inlet/outlet plenums are proposed and integrated on the MUMPFHS, which could achieve a uniform flow distribution in each manifold channel. Thermal and exergy analysis confirms that taking the plenums into consideration increases the friction power which can be compensated by the improvement of electrical power due to the decrease of solar cell temperature. The present simulation results indicate that our designed MUMPFHS could increase the feasibility of using HCPV under higher solar concentration with safe operation.

Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

Numerical Analysis on the Performance of High Concentration Photovoltaic Systems Under the Nonuniform Energy Flow Density

Photovoltaic panels can directly convert solar energy into electricity, but temperature will have a certain impact on the efficiency of photovoltaic cells. Especially under the condition of nonuniform energy flow density of high-power concentration, it is of great significance to maintain the temperature uniformity of cells. Therefore, based on the radiation under nonuniform heat flux density, four heat exchangers were proposed: single-channel serpentine flow, multi-channel flat plate, full jet, and single-jet nozzle. Taking into account the uniformity of the cell temperature, the single-jet nozzle and single-channel serpentine flow can better maintain the uniformity of the temperature field compared with other heat exchangers. Especially under high-concentration energy flow density, considering the quality of heat and electricity, the performance of the four-jet nozzles is the best from the perspective of exergy efficiency. Under the condition of four-jet nozzles, the electrical efficiency and thermal efficiency of the cell can be maintained at about 29 and 62.5%, respectively, and the exergy efficiency of the system can reach 31%.

Performance Analysis of a Prototype High‐Concentration Photovoltaic System Coupled to Silica Optical Fibers

High‐concentration photovoltaic (HCPV) systems are one of the most promising technologies for the generation of renewable energy with high‐conversion efficiency. Their development is still at an early stage, but the possibility of integrating high‐concentration systems into buildings offers new opportunities to achieve the net‐zero‐energy building goal. Herein, the optical and energetic performance of a hybrid daylighting−HCPV prototype based on pure‐ or doped‐silica optical fibers (OFs) to guide 2000× concentrated sunlight inside the buildings is evaluated. There, the light can either be used to illuminate interior spaces or projected on solar cells to generate electricity. The system equipped with a single 400 μm core‐diameter OF is demonstrated to achieve a total efficiency of 15% and an optical efficiency of 45%.

Application of LCA to Determine Environmental Impact of Concentrated Photovoltaic Solar Panels—State-of-the-Art

Photovoltaic systems represent a leading part of the market in the renewable energies sector. Contemporary technology offers possibilities to improve systems converting sun energy, especially for the efficiency of modules. The paper focuses on current concentrated photovoltaic (CPV) technologies, presenting data for solar cells and modules working under lab conditions as well as in a real environment. In this paper, we consider up-to-date solutions for two types of concentrating photovoltaic systems: high-concentration photovoltaics (HCPV) and low-concentration photovoltaics (LCPV). The current status of CPV solar modules was complemented by the preliminary results of new hybrid photovoltaic technology achieving records in efficiency. Compared to traditional Si-PV panels, CPV modules achieve greater conversion efficiency as a result of the concentrator optics applied. Specific CPV technologies were described in terms of efficiency, new approaches of a multijunction solar cell, a tracking system, and durability. The results of the analysis prove intensive development in the field of CPV modules and the potential of achieving record system efficiency. The paper also presents methods for the determination of the environmental impact of CPV during the entire life cycle by life cycle assessment (LCA) analysis and possible waste management scenarios. Environmental performance is generally assessed based on standard indicators, such as energy payback time, CO2 footprint, or GHG emission.

Bidirectional planar-displacement waveguide tracker for high-concentration photovoltaics.

A bidirectional planar-displacement waveguide tracker was devised to replace the traditional two-axis tracking system for high-concentration photovoltaics, with improved module thickness, optical field uniformity, and current matching. The concentrating magnification reaches 725 times, and the sun tracking angle is more than 170°, which is equivalent to 11.3 tracking hours per day. The module thickness is only 6.16 cm. This design enabled us to place the module flat on the ground, in which swing was not required. This will greatly improve the mechanical strength and the lifetime of the module and solve the development dilemma faced by III-V multijunction solar cells.

Performance evaluation of a high concentrator photovoltaic integrating a Fresnel lens in Saudi Arabia: A case study

SummarySaudi Arabia has plentiful freely accessible solar energy with daily total Direct Normal Irradiance on the higher side. Furthermore, because of its extensive desert land with over 2 million km2 expanse and high clearance index, the country could be a successful contender for accommodating the High Concentrator Photovoltaic (HCPV) technology. This technology, which assimilates Fresnel lens, has drawn more attention particularly after presenting III‐V Multi‐Junction solar cells for terrestrial uses since they keep achieving new conversion efficiency accomplishments. This article evaluates the HCPV performance in Saudi Arabia using direct normal irradiance data gathered in recent times. To undertake this assessment, a validated developed optical simulation using a ray‐tracing technique is employed to evaluate the maximum and average power output that may be gathered using a single HCPV unit in the primary regions and cities in the nation. Results indicate that the highest values for average and maximum annual power yield belong to the Western Inland area with one HCPV unit having a Fresnel lens with a 0.25×0.25 m2 aperture area, and those values are over 36 and 59 kWh, respectively. Concerning cities, Tabuk has HCPV unit producing the highest average annual yield greater than 39 kWh while the maximum annual yield crosses 60 kWh. Hence, the yearly electrical energy yield of 194 such units that use an area less than 12.2 m2 corresponds to approximately 33% of the electricity demanded yearly by a typical home in Saudi Arabia, which includes heavy energy‐consuming devices like air conditioners. Additionally, the estimated pollution potentially displaced by these units as per the global warming potential indicator is around eight tons of CO2 annually.

Impact of microchannel heat sink configuration on the performance of high concentrator photovoltaic solar module

Concentrating photovoltaic technology is growing rapidly among other solar energy technologies, as it reaches an electrical conversion efficiency up to 46%. The solar cell temperature increases during the conversion process, which in turn negatively affects the system’s performance by decreasing its efficiency. Thus, for safe and efficient operation, low and uniform temperature should be achieved. In this work, numerical simulations were completed to study and compare two microchannel heat sink designs as cooling devices for a high concentration photovoltaic (HCPV) system. ANSYS Fluent software was employed to solve three-dimensional conjugate heat transfer equations. The comparison was conducted under uniform solar radiation with a concentration ratio of 1000 suns (1 sun = 1000 W/m2) and a wide range of coolant inlet flowrate. The impact of heat sink design and coolant inlet flowrate variation were studied and highlighted regarding average cell temperature, electrical efficiency, temperature non-uniformity, and local temperature distribution. The results showed that heat sink design has a remarkable impact on the cooling performance of the HCPV/Thermal system. Whereas, configuration 1 achieved a lower average cell temperature by 11% than configuration 2, while the electrical efficiency was increased by 1.4%, at the minimum studied flowrate.

Development of high concentration photovoltaics (HCPV) power plants in the US Southwest: Economic assessment and sensitivity analysis

High concentration photovoltaic (HCPV) technologies offer several advantages over typical PV systems. In this study, a detailed economic assessment and sensitivity analysis of deploying HCPV plants in the US southwest is performed. To do this, a 20 MWdc HCPV power plant is designed using the System Advisor Model (SAM) and is evaluated from both technical and financial aspects. The sensitivity analysis shows that reducing the installed cost per capacity of the HCPV system can significantly improve the economics and reduce the levelized cost of electricity (LCOE) and levelized power purchase agreement (LPPA). Also, providing proper incentives including both investment tax credits (ITC) and production tax credit (PTC), loan debt ratio, and interest rate are among the most influential parameters. The analysis shows that with the 30% ITC, the LCOE, and LPPA of the designed HCPV projects are between $65.4/MWh and $69.3/MWh and between $71.0/MWh and $75.2/MWh, respectively. The estimated LCOE and LPPA values are almost 50% higher than the utility-scale PV projects. If proper funding is provided to continue the support of the HCPV system, they would become more economical and competitive with PV plants. Federal and state government policies must also be established to advocate HCPV systems.

Numerical analysis of passive cooled ultra-high concentrator photovoltaic cell using optimal heat spreader design

In the high concentrator photovoltaic (HCPV) systems with solar concentration ratios up to 2000 Suns, significant heat is generated in the used solar cell layer. This high generated heat requires an efficient and smart cooling technique to keep it operating at a safe operating temperature. In this paper, another ultra-high concentrator photovoltaic (UHCPV) system with a smaller cell area of 1 mm2 operating at a high solar concentration ratio (CR) up to 10,000 Suns is proposed. This smaller area requires a simple passive cooling technique even at high CR. The optimal dimensions of a passive cooling method using heat spreader are defined. A 3D thermal model for the multijunction solar cell with the heat spreader coupled with the multi-objective genetic optimization algorithm is used to define the optimal heat spreader dimensions . The model is validated with the results in the literature. The model is used to estimate the cell temperature generated electric power, and cell efficiency at different wind speed, ambient temperature, solar radiation, heat spreader length, thickness, and CR. The heat spreader dimensions were optimized for CR = 6000 suns, the optimal thickness and length were 2 mm and a of 47.5 mm, respectively. These dimensions are enough for the safe operation of the UHCPV at CR of 6000 Suns. As a case study, for a UHCPV module with a total number of cells of 10 by 10, the generated power is around 319 W at CR of 10,000 Suns. At the same condition, the monocrystalline silicon solar cell in the PERSEID SOLAR company can generate a maximum power of 144.9 W/m2. For the same area, for the UHCPV module, the generated electric power is around 319 W for 1 m2 of the module. Therefore, around 120% increase in the power can be accomplished with the use of the UHCPV module. In the UHCPV module, the total area of the cell is around 1 cm by 1 cm. Therefore, the module cost could be very low.

A Forecasting-Based Control Algorithm for Improving Energy Managment in High Concentrator Photovoltaic Power Plant Integrated with Energy Storage Systems

The High Concentrator Photovoltaic (HCPV) technology, due to its high efficiency, is considered one of the most promising solutions for the exploitation of sun-irradiation-based Renewable Energy Sources (RES). Nevertheless, the HCPV production is strictly connected to the Direct Normal Irradiation (DNI) making this photovoltaic technology more sensible to cloudiness than traditional ones. In order to mitigate the power intermittence and improve production programmability, the integration between Energy Storage Systems (ESSs) and HCPV, resorting to forecasting algorithms, has been investigated. Specifically, a local weather forecasting algorithm has been used for estimating the daily time evolution of DNI, air Temperature (T), Wind Speed (WS), and Air Mass (AM). These data are subsequently processed by means of an accurate HCPV model for the estimation of one day-ahead daily power production profile. The processing of HCPV forecasted generation by means of a properly tuned filter-based algorithm allows one day-ahead the definition of power profiles of ESS and power plant respectively, considering also the ESS constraints and the characteristic of the implemented real-time control algorithm. The effectiveness of the proposed forecasting model and control algorithm is verified through a simulation study referring to the solar power plant constituted by HCPV and ESS installed in Ottana, Italy. The results highlight that the application of the proposed approach lessens the power fluctuation effect caused by HCPV generation preserving the batteries at the same time. The feasibility and advantages of the proposed approach are finally presented.

Performance evaluation of single multi-junction solar cell for high concentrator photovoltaics using minichannel heat sink with nanofluids

High concentrated photovoltaic systems (HCPV) have demonstrated the potential to achieve high conversion power over conventional photovoltaic panels (PV) especially for areas with high solar irradiance. However, the multi-junction (MJ) solar cells may be subjected to damage if the temperature exceeds 110 °C as recommended by the manufacturer. Hence, in this paper, the overall performance of a 1cm2 MJ solar cell with a mini-channel heat sink subjected to high concentration ratio (500×to2000×) is investigated to find improved method of reducing the cell temperature. The impact of using water, Al2O3/water, and SiO2/water on the effectiveness of heat transfer, temperature distribution on the MJ solar cell, and performance evaluation criteria are studied. Also, the evaluation of the HCPVT system performance is presented. A 3D computational modelling is performed and the experimental measurements for the thermal conductivity are constructed for the different fluids and entered in the simulation. Nanofluids maintain the maximum solar cell temperature at 95.25 °C and 67.1 °C at Reynolds number (Re) of 8.25 and 82.5 respectively and a concentration ratio of 2000×. The overall efficiency of the system increases by 3.82% at Re of 8.25 and a concentration ratio of 500× by using SiO2/water at 5%.

Very Short-Term Power Forecasting of High Concentrator Photovoltaic Power Facility by Implementing Artificial Neural Network

Concentrator photovoltaic (CPV) is used to obtain cheaper and more stable renewable energy. Methods which predict the energy production of a power system under specific circumstances are highly important to reach the goal of using this system as a part of a bigger one or of making it integrated with the grid. In this paper, the development of a model to predict the energy of a High CPV (HCPV) system using an Artificial Neural Network (ANN) is described. This system is located at the University of Rabat. The performed experiments show a quick prediction with encouraging results for a very short-term prediction horizon, considering the small amount of data available. These conclusions are based on the processes of obtaining the ANN models and detailed discussion of the results, which have been validated using real data.

Energetic, economic, and environmental (3 E) performances of high concentrated photovoltaic large scale installations: Focus on spatial analysis of Morocco

Producing electricity from a renewable source is a major challenge in Morocco nowadays and high concentrated photovoltaic (HCPV) is becoming an attractive solution to ensure clean energy generation due to its high efficiency. The aim of this paper is to estimate the « Energetic, economic, and environmental » performances of large scale HCPV power plants in the major Moroccan climatic zones and to compare their feasibility to PV plants. The mathematical model for estimating the energetic, economic, and environmental performances of large scale HCPV plants is shown, sensitivity and comparison analysis are exhibited. Another goal of the paper is the optimization of the performances of the algorithm through the study of the effect of different parameters. Our major finding is that the large scale HCPV plants are more competitive than PV plants in Errachidia climatic zone where the (capacity factor, LCOE) take the values (26.07%,8.57c$/kWh). Moreover, the capacity factor of large scale HCPV power plants is the most sensitive to the temperature coefficient while the (LCOEnominal, LCOEreal, NPV) are the most sensitive to the analysis period. The quantity of CO2 mitigated reaches a maximal value in the Errachidia zone with 2.59 × 105 tons of carbon per year avoided, and the cost of carbon gained there is estimated to be 10.4 M$. Innovative GIS maps of energetic, economic, and environmental performances of large scale HCPV power plants for all Morocco are given.

Thermal management of high concentrator solar cell using new designs of stepwise varying width microchannel cooling scheme

High concentrator photovoltaic (HCPV) system are generally exposed to high solar concentration ratios and reach high temperatures. An advanced cooling technique is compulsory to attain the highest net output power along with the safe operation of the system components. Different designs of stepwise varying width microchannel heat sink are investigated in this study. The main purpose of this study is to investigate the influence of the channel geometry of longitudinal rectangular internal fins and different water inlet mass flow rates on the performance of an HCPV system. A three-dimensional thermal model is developed and used to compare the performance of four different designs of stepwise varying width microchannel heat sinks. These designs are compared with the conventional multichannel heat sink design. The results show that the heat sink design and the coolant mass flow rate have a significant impact on the cell temperature, electrical cell efficiency, system thermal efficiency, electrical exergy efficiency, thermal exergy efficiency, total exergy efficiency and thermal resistance of the heat sinks. For instance, using one of the proposed stepwise varying width microchannel heat sink at solar concentration ratio of 1000 suns and increasing the coolant flowrate from 25 to 1000 g/min decreased the solar cell temperature from around 71.7° C to 40° C with solar cell temperature non-uniformity decreased from 15.5 °C to 9 °C respectively.

Design and performance analysis of high efficiency non-imaging concentrated optical system

Aiming at the low optical efficiency of Fresnel lens, a high-efficiency non-imaging concentrated optical (NICO) system composed of an aspheric lens and a trumpet lens was designed. The aspheric lens was optimized in sequential mode of Zemax, and the geometric radius of its image spot was reduced from 42 mm to 1.7 mm by minimizing the spherical aberration. The aspheric lens and trumpet lens were modeled and optimized in non-sequential mode of Zemax, and the NICO system with 87% optical efficiency and 0.9° received angle was achieved by Monte Carlo ray tracing analysis. Finally, the packaging and testing of the high concentrated photovoltaic (HCPV) module were completed based on samples of an aspheric lens array and 48 trumpet lenses. The test results showed that the photoelectric conversion efficiency of the module reached 30.03%, which was significantly improved compared with the HCPV module composed of the Fresnel lens.

Maximum power output prediction of HCPV FLATCON® module using an ANN approach

The estimation of the electrical power output and energy yield of high concentration photovoltaic (HCPV) modules is a hard task because of the many parameters involved. In this work, we propose the usage of an Artificial Neural Networks (ANN) method to estimate the maximum power output of a FLATCON® CPV-module manufactured by Fraunhofer ISE. The advantage of the ANN is that it is a part of the Artificial Intelligence Deep Learning domain, which makes it easy to model complex systems. A detailed knowledge about the underlying module technology is not necessary. In this work, various meteorological parameters are tested as inputs of the ANN including spectral matching ratios for considering the spectral variation of the solar irradiance to evaluate the maximum power output of the HCPV module under study. Eleven scenarios considering different combinations of input parameters have been investigated. It is demonstrated that the ANN gives excellent results and allows for an accurate prediction of the HCPV module’s instantaneous power output with only a few amount of data used on training the ANN. The model has been tested using the measured data set of a FLATCON® CPV-module located on the rooftop of the Fraunhofer ISE in Freiburg, Germany. The module has been electrically characterized outdoors in the period from April 2013 to April 2014. The accuracy of the proposed ANN approach was analyzed using this measurement data in combination with error metrics. It was found that the best agreement between the measured and the predicted maximum power output was achieved when using direct normal irradiance, wind speed, ambient temperature and spectral matching ratios as input. The normalized root mean square error for the maximum power output over one year is found to be between 2.2 and 4.6%. The deviation of the modelled energy yield to the measured one is in the range of 0.2–2.2%.

Simulation of large PV energy facilities with SAM HCPV and PV detailed models

Here we compare the measured energy production of the solar photovoltaic (PV) energy facilities of Solar Star and Desert Sunlight with the values computed in National Renewable Energy Laboratory (NREL) System Advisor Model (SAM), by using the SAM database for the typical weather, and the different models available, the high concentration photovoltaic (HCPV) model, as well as the PV detailed model. Both models are semi-empirical. The HCPV is the most sophisticated model, permitting the specification of a much larger number of parameters. The detailed PV model is less flexible. The comparison shows that SAM computes winter and summer energy productions that are much closer than what is shown by the experiments, dramatically underrating the seasonal variability. This is due to a solar resource for direct normal irradiance during winter and summer that is much closer to what is shown by other databases, such as Weather Spark, for their incident shortwave solar energy inclusive of seasonal variations, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. The contribution highlights the issue of the mostly missing validation of renewable energy tools, in needs of proper high-frequency simultaneous weather and plant data, both at the system and the level of the individual components, before their use for performance estimations.

Implementation of a modified circuit reconfiguration strategy in high concentration photovoltaic modules under partial shading conditions

A modified circuit reconfiguration (MCR) technique for high concentration photovoltaic (HCPV) modules under partial shading conditions (PSCs) is proposed. Although HCPV modules have high conversion efficiency, they are sensitive to changing environments, especially PSCs. In response, the MCR strategy exploits the reconfigurable wiring of HCPV modules to implement the dynamic circuit reconfiguration (DCR) technique. In doing so, the hardware switches and complex control algorithms of the conventional DCR are simplified to reduce cost. Moreover, an irradiation estimation method is proposed for string current equalization using existing switches and connections. Two circuit-model prototypes, one square and one rectangular, were simulated to evaluate the proposed MCR strategy. Evaluation results demonstrate that the average output-power and conversion-efficiency improvements of the square and rectangular modules were around 31.07% and 5.00%, and 32.79% and 5.23%, respectively, when compared with the original Series connection topology. In addition, after reconfiguration by MCR, the module’s GMPP power was improved and the number of LMPPs reduced, which simplified the P-V curves. Furthermore, reliability tests demonstrated that with a small reconfiguration processing time ratio (0.06–0.28%), the daily energy harvested from the rectangular module was improved around 15%. The proposed MCR strategy has the advantages of reducing the hardware/software costs and lowering circuit losses. Additionally, the MCR method can increase the output power and efficiency of an HCPV module with high dispersion ability. The proposed method and prototypes can also be extended to larger scale arrays or implemented with other PV systems.

Life Cycle Assessment of New High Concentration Photovoltaic (HCPV) Modules and Multi-Junction Cells

Worldwide electricity consumption increases by 2.6% each year. Greenhouse gas emissions due to electricity production raise by 2.1% per year on average. The development of efficient low-carbon-footprint renewable energy systems is urgently needed. CPVMatch investigates the feasibility of mirror or lens-based High Concentration Photovoltaic (HCPV) systems. Thanks to innovative four junction solar cells, new glass coatings, Position Sensitive Detectors (PSD), and DC/DC converters, it is possible to reach concentration levels higher than 800× and a module efficiency between 36.7% and 41.6%. From a circular economy’s standpoint, the use of concentration technologies lowers the need in active material, increases recyclability, and reduces the risk of material contamination. By using the Life Cycle Assessment method, it is demonstrated that HCPV presents a carbon footprint ranking between 16.4 and 18.4 g CO2-eq/kWh. A comparison with other energy means for 16 impact categories including primary energy demand and particle emissions points out that the environmental footprint of HCPV is typically 50 to 100 times lower than fossil fuels footprint. HCPV’s footprint is also three times lower than that of crystalline photovoltaic solutions and is close to the environmental performance of wind power and hydropower.