Optical efficiency–concentration ratio trade-off for a flat panel photovoltaic system with diffuser type concentrator

2012 ◽  
Vol 103 ◽  
pp. 35-40 ◽  
Author(s):  
Jung Min Kim ◽  
Partha S. Dutta
Keyword(s):  
Concentration Ratio ◽  
Photovoltaic System ◽  
Flat Panel ◽  
Optical Efficiency ◽  
Trade Off

A Novel Lens-Walled Compound Parabolic Concentrator for Photovoltaic Applications

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Yuehong Su ◽  
Gang Pei ◽  
Saffa B. Riffat ◽  
Hulin Huang
Keyword(s):  
Concentration Ratio ◽  
Incidence Angle ◽  
Small Degree ◽  
Photovoltaic System ◽  
Acceptance Angle ◽  
Optical Efficiency ◽  
Concentrate Solar Radiation ◽  
Compound Parabolic Concentrator ◽  
Photovoltaic Applications ◽  
The Common

A compound parabolic concentrator (CPC) is a nonimaging concentrator that can concentrate solar radiation coming within its acceptance angle. A low concentration CPC photovoltaic system has the advantages of reduced Photovoltaics (PVs) cell size, increased efficiency and stationary operation. The acceptance angle of a CPC is associated with its geometrical concentration ratio, by which the size of PV cell could be reduced. Truncation is a way to increase the actual acceptance angle of a mirror CPC, but it also reduces the geometrical concentration ratio. On the other hand, a solid dielectric CPC can have a much larger acceptance angle, but it has a larger weight. To overcome these drawbacks, this study presents a novel lens-walled CPC that has a thin lens attached to the inside of a common mirror CPC or has the lens to be mirror coated on its outside surface. The shape of the lens is formed by rotating the parabolic curves of a CPC by a small degree internally around the top end points of the curves. The refraction of the lens allows the lens-walled CPC to concentrate light from wider incidence angle. The commercial optical analysis software PHOTOPIA is used to verify the principle of the presented lens-walled CPC and examine its optical performance against the common CPCs. As an example, the simulation is aimed to evaluate whether a lens-walled CPC with a geometrical concentration ratio of 4 has any advantage over a common CPC with a geometrical concentration ratio of 2.5 in terms of actual acceptance angle, optical efficiency and optical concentration ratio.

The Effect of Concentrated Light Intensity on Temperature Coefficient of the InGaP/InGaAs/Ge Triple-Junction Solar Cell

2015 ◽  
Vol 8 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Zilong Wang ◽  
Hua Zhang ◽  
Wei Zhao ◽  
Zhigang Zhou ◽  
Mengxun Chen
Keyword(s):  
Solar Cell ◽  
Light Intensity ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Triple Junction ◽  
Concentration Ratio ◽  
Crystalline Silicon ◽  
Photovoltaic System ◽  
Solar Pv ◽  
Junction Solar Cell

Research on automatic tracking solar concentrator photovoltaic systems has gained increasing attention in developing the solar PV technology. A paraboloidal concentrator with secondary optic is developed for a three-junction GaInP/GalnAs/Ge solar cell. The concentration ratio of this system is 200 and the photovoltaic cell is cooled by the heat pipe. A detailed analysis on the temperature coefficient influence factors of triple-junction solar cell under different high concentrations (75X, 100X, 125X, 150X, 175X and 200X) has been conducted based on the dish-style concentration photovoltaic system. The results show that under high concentrated light intensity, the temperature coefficient of Voc of triple-junction solar cell is increasing as the concentration ratio increases, from -10.84 mV/°C @ 75X growth to -4.73mV/°C @ 200X. At low concentration, the temperature coefficient of Voc increases rapidly, and then increases slowly as the concentration ratio increases. The temperature dependence of η increased from -0.346%/°C @ 75X growth to - 0.103%/°C @ 200X and the temperature dependence of Pmm and FF increased from -0.125 W/°C, -0.35%/°C @ 75X growth to -0.048W/°C, -0.076%/°C @ 200X respectively. It indicated that the temperature coefficient of three-junction GaInP/GalnAs/Ge solar cell is better than that of crystalline silicon cell array under concentrating light intensity.

scholarly journals Theoretical Investigation of the Temperature Limits of an Actively Cooled High Concentration Photovoltaic System

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1902 ◽  
Author(s):  
Asmaa Ahmed ◽  
Katie Shanks ◽  
Senthilarasu Sundaram ◽  
Tapas Kumar Mallick
Keyword(s):  
Solar Cell ◽  
Concentration Ratio ◽  
Photovoltaic System ◽  
Thermal System ◽  
Outlet Temperature ◽  
Water Mixture ◽  
High Concentration ◽  
Cell Temperature ◽  
Photovoltaic Thermal System ◽  
Different Types

Concentrator photovoltaics have several advantages over flat plate systems. However, the increase in solar concentration usually leads to an increase in the solar cell temperature, which decreases the performance of the system. Therefore, in this paper, we investigate the performance and temperature limits of a high concentration photovoltaic Thermal system (HCPVT) based on a 1 cm2 multi-junction solar cell subjected to a concentration ratio from 500× to 2000× by using three different types of cooling fluids (water, ethylene glycol and water mixture (60:40), and syltherm oil 800). The results show that, for this configuration, the maximum volumetric temperature of the solar cell did not exceed the manufacturer’s recommended limit for the tested fluids. At 2000× the lowest solar cell temperature obtained by using water was 93.5 °C, while it reached as high as 109 °C by using syltherm oil 800, which is almost equal to the maximum operating limit provided by the manufacturer (110 °C). Overall, the best performance in terms of temperature distribution, thermal, and electrical efficiency was achieved by using water, while the highest outlet temperature was obtained by using syltherm oil 800.

Characteristics of the InGaP/InGaAs/Ge Triple-Junction Solar Cells with Concentration Photovoltaic System

2011 ◽  
Vol 148-149 ◽  
pp. 773-777
Author(s):  
Zi Long Wang ◽  
Hua Zhang ◽  
Hai Tao Zhang ◽  
Ye Li
Keyword(s):  
Solar Cell ◽  
Concentration Ratio ◽  
Photovoltaic System ◽  
Solar Concentrator ◽  
Solar Pv ◽  
System Research ◽  
Uniform Illumination ◽  
Automatic Tracking ◽  
Second Stage ◽  
System A

The research on automatic tracking solar concentrator photovoltaic system research has become one of issues of solar PV technology. Aiming at the problem of cell performance degradation which caused by the non-uniform illumination in the concentrating photovoltaic system. A dish-style concentrating photovoltaic system with second stage concentrator was designed and built in this article. The author measured the performance of three junction GaInP/GaInAs/Ge solar cell. According to experiment result, the Pmm of solar cell was increased from 1.54 W/cm2 to 1.88 W/cm2. The η of solar cell was increased from 32% to 34.1% separately that compared with the concentrating photovoltaic system which without the second stage concentrator at the same concentration ratio(150X)

Optical Analysis of a Heliostat Array With Linked Tracking

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
M. T. Dunham ◽  
R. Kasetty ◽  
A. Mathur ◽  
W. Lipiński
Keyword(s):  
Concentration Ratio ◽  
Tracking System ◽  
Average Concentration ◽  
Solar Concentrator ◽  
Optical Performance ◽  
Optical Analysis ◽  
Optical Efficiency ◽  
The North ◽  
The Individual ◽  
East West

The optical performance of a novel solar concentrator consisting of a 400 spherical heliostat array and a linked two-axis tracking system is analyzed using the Monte Carlo ray-tracing technique. The optical efficiency and concentration ratio are compared for four different heliostat linkage configurations, including linkages of 1 × 1, 1 × 2, 2 × 2, 4 × 4, and 5 × 5 heliostats for 7-hour operation and the selected months of June and December. The optical performance of the concentrator decreases with the increasing number of heliostats in the individual groups due to increasing optical inaccuracies. In June, the best-performing linked configuration, in which 1 heliostat in the east-west direction and 2 heliostats in the north-south direction are linked, provides a monthly-averaged 7-hour optical efficiency and average concentration ratio of 79% and 511 suns, respectively. In December, the optical efficiency and the average concentration ratio decreases to 61% and 315 suns, respectively.

Design and Analysis of a Low Reflecting Concentrating Photovoltaic System

2012 ◽  
Vol 517 ◽  
pp. 791-796
Author(s):  
Cheng Yao Wang ◽  
Yin Xu ◽  
Yao Ming Zhang ◽  
Yong Ming Hua
Keyword(s):  
Electric Power ◽  
Concentration Ratio ◽  
Tracking System ◽  
Weather Conditions ◽  
Mathematic Model ◽  
Photovoltaic System ◽  
Voltage Profile ◽  
Pv System ◽  
Tracking Errors ◽  
Flux Concentration

In this paper, a concentrating photovoltaic (CPV) system with low ratio was successfully developed. In the design of CPV concentrator, a quasi-parabolic reflector was adopted. With the research of basic optical mechanisms, a mathematic model was built with the corresponding program. In addition, the width of light spot was analyzed with considering the symmetry of tracking errors and glass deformation in manufacture to identify reasonable values. The system was designed with a reflector of 10 flat mirrors, which has a geometrical concentration ratio of 8.18 and a flux concentration ratio of 5. The concentrating photovoltaic system was investigated experimentally under the various weather conditions. The output voltage profile and the output power of the flat PV system and the CPV system were presented to analyze the concentration ratio and the electric power. And the influence of soiling was also discussed. The results showed that the performance of tracking system was good in a clear day. Compared to the flat cell with the same system, the electric power was nearly increased by 4-5 times.

Design, Evaluation, and Testing of a Moderately Concentrating, Nontracking Solar Energy Collector

1981 ◽  
Vol 103 (1) ◽  
pp. 34-41 ◽  
Author(s):  
A. Olvera ◽  
R. B. Bannerot
Keyword(s):  
Solar Energy ◽  
Heat Loss ◽  
Thermal Performance ◽  
Heat Recovery ◽  
Concentration Ratio ◽  
Side Wall ◽  
Recovery Factor ◽  
Design Evaluation ◽  
Optical Efficiency ◽  
Overall Heat Loss Coefficient

The thermal performance of a moderately concentrating, nontracking, trough-like solar energy collector is predicted based on a series of experimental evaluations of its components. Four reflector designs were constructed and tested. Two were one-facet side wall (reflector) designs; two were two-facet designs. Six simple tubular, nonevacuated receiver designs were tested. A collector utilizing one of the reflector designs, geometric concentration ratio of 2.6, and one of the receiver designs was constructed and tested. The predicted performance (an effective overall heat loss coefficient of 4.6 W/m2–°C, an optical efficiency of 0.71 and a heat recovery factor of 0.95) closely approximated the actual thermal performance of the collector. The component evaluations are discussed in such detail that the analysis could easily be extended to other designs by the reader.

scholarly journals Optical Design of a Novel Two-Stage Dish Applied to Thermochemical Water/CO2 Splitting with the Concept of Rotary Secondary Mirror

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3553
Author(s):  
Song Yang ◽  
Jun Wang ◽  
Peter D. Lund
Keyword(s):  
Mathematical Model ◽  
Ray Tracing ◽  
Concentration Ratio ◽  
Thermal Water ◽  
Optical Design ◽  
Two Stage ◽  
Optical Efficiency ◽  
Primary Mirror ◽  
Secondary Mirror ◽  
Ray Tracing Simulation

In this paper, a novel two-stage dish concentrator (TSD) with a rotary secondary mirror (SM) is presented for solar thermal water/CO2 splitting. An in-house code for ray-tracing simulation of the concentrator was developed and validated. Among all feasible geometries, a hyperboloid with an upper sheet is the most popular option and is widely used as a secondary reflector, which is mainly discussed here. All para-hyperboloid geometric combinations can be categorized into three typical patterns (φ1 < π/2, φ1 = π/2, φ1 > π/2, φ1 = field angle of PM). The initial designs of the TSD, respective to different off-axis levels for each combination, were first designed. Then a new mathematical model was introduced to reshape the SM to reach optimal truncated designs. Finally, a new concept of an off-axis primary mirror (PM) combined with the truncated SM was evaluated by using the in-house ray-tracing code. The results include the optical efficiency, concentration ratio and intercepted radiant flux. The best solutions with the highest optical efficiency fall in the range π/2 ≤ φ1 ≤ (π − arcsin 0.8) rads and 0.4 ≤ NA2 ≤ 0.6 (NA2 = sin φ2, φ2 = field angle of SM), which vary with the concentration ratio and inclination angle.

scholarly journals Improvement in the Flux Uniformity of the Solar Dish Concentrator System through a Concave Quartz Window

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Du-zhong Nie ◽  
You-duo Peng ◽  
Jian Yan ◽  
Cheng-ji Mi ◽  
Yong-xiang Liu ◽  
...  
Keyword(s):  
Cylindrical Cavity ◽  
Peak Concentration ◽  
Concentration Ratio ◽  
Optimal Parameter ◽  
High Strength ◽  
Hyperbolic Tangent ◽  
Focal Distance ◽  
Optical Efficiency ◽  
Quartz Window ◽  
Parabolic Dish

A nonuniform and high-strength heat flux load would reduce the working efficiency, safety, and in-service life of a cavity receiver. Four types of concave quartz windows, including conical, spherical, sinusoidal, and hyperbolic tangent, were proposed to be used in the cylindrical cavity receiver of a solar dish concentrator system, which can improve the flux uniformity and reduce the peak concentration ratio of the receiver. For each concave quartz window, 36 structural schemes were offered. Based on the Monte Carlo ray-tracing method, the results showed that the nonuniformity coefficient of the receiver was 0.68 and the peak concentration ratio was 1320.21 by using a plane quartz window. At the same time, when the receiver is in the best optical performance, it is the receiver with sinusoidal, conical, spherical, and hyperbolic tangent quartz windows, respectively. The optical efficiency of the receiver with the above four types of quartz windows was basically the same as that of the receiver with the plane quartz window, but their nonuniformity coefficients were reduced to 0.31, 0.35, 0.36, and 0.39, respectively, and the peak concentration ratio was reduced to 806.82, 841.31, 853.23, and 875.89, respectively. Obviously, the concave quartz window was better than the plane quartz window in improving the flux uniformity. Finally, a further study on the sinusoidal quartz window scheme of all of the above optimal parameter schemes showed that when the installation position of the receiver relative to the dish concentrator was changed, the flux uniformity of the receiver could continue to improve. When the surface absorptivity of the receiver was reduced, the optical efficiency would be reduced. For the parabolic dish concentrator with different focal distance, the concave quartz window can also improve the uniformity of the flux distribution of the cylindrical cavity receiver.

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