Optical Losses through Gaps of CPCs with One-Sided Flat Absorber

2015 ◽  
Vol 737 ◽  
pp. 46-52
Author(s):  
Feng Tang ◽  
Run Sheng Tang
Keyword(s):  
Tilt Angle ◽  
Optical Loss ◽  
Radiation Loss ◽  
Optical Losses ◽  
Multiple Reflections ◽  
Acceptance Angle ◽  
Direct Radiation ◽  
Direct Irradiation ◽  
Solar Resource ◽  
East West

In this work, the angular dependence of optical losses through gaps, constructed by truncating reflectors near the absorbers, of CPCs with one-sided flat absorber was presented, and the annul radiation loss through gaps of east-west aligned CPCs is theoretically investigated. Results show that the optical losses are mainly resulted from direct radiation loss through gaps due to direct irradiation on gaps, and the loss of radiation that arrive on gaps from reflectors after multiple reflections is considerable small and can be neglected in solar calculations especially for truncated CPCs. Results also show that the annual direct radiation loss is dependent on geometric parameters of CPCs but seems independent on solar resource in sites where CPCs are used, and the annual radiation loss of full CPCs oriented in east-west direction with the tilt-angle of aperture being yearly fixed is almost identical to average optical loss of the CPC over its acceptance angle.

scholarly journals Performance and Design Optimization of Two-Mirror Composite Concentrating PV Systems

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2875
Author(s):  
Guihua Li ◽  
Yamei Yu ◽  
Runsheng Tang
Keyword(s):  
Tilt Angle ◽  
Three Dimensional ◽  
Acceptance Angle ◽  
Pv System ◽  
Pv Systems ◽  
Calculation Results ◽  
The One ◽  
A Site ◽  
Plate Absorber ◽  
East West

The reflectors of a linear solar concentrator investigated in this work consisted of two plane mirrors (2MCC), and they were designed in such a way that made all radiation within the acceptance angle (θa) arrive on flat-plate absorber, after less than two reflections. To investigate the performance of an east–west aligned 2MCC-based photovoltaic (PV) system (2MCPV), a mathematical procedure was suggested based on the three-dimensional radiation transfer and was validated by the ray-tracing analysis. Analysis indicated that the performance of 2MCPV was dependent on the geometry of 2MCC, the reflectivity of mirrors (ρ), and solar resources in a site, thus, given θa, an optimal geometry of 2MCC for maximizing the annual collectible radiation (ACR) and annual electricity generation (AEG) of 2MCPV in a site could be respectively found through iterative calculations. Calculation results showed that when the ρ was high, the optimal design of 2MCC for maximizing its geometric concentration (Cg) could be utilized for maximizing the ACR and AEG of 2MCPV. As compared to similar compound parabolic concentrator (CPC)-based PV systems, the 2MCPV with the tilt-angle of the aperture yearly fixed (1T-2MCPV), annually generated more electricity when the ρ was high; and the one with the tilt-angle adjusted yearly four times at three tilts (3T-2MCPV), performed better when θa < 25° and ρ > 0.7, even in sites with poor solar resources.

A New Troughlike Nonimaging Solar Concentrator

2001 ◽  
Vol 124 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Eduardo A. Rinco´n ◽  
Fidel A. Osorio
Keyword(s):  
Concentration Ratio ◽  
Glass Tube ◽  
Two Dimensional ◽  
Solar Concentrator ◽  
Steam Generation ◽  
Acceptance Angle ◽  
Practical Applications ◽  
Optimal Shapes ◽  
Heating Steam ◽  
East West

A new two-dimensional concentrator for solar energy collection has been developed. The concentrator has the following advantages, when compared with the classic Compound Parabolic Concentrators invented by Roland Winston, W. T. Welford, A. Rabl, Baranov, and other researchers: 1) It allows the use of parabolic mirrors, which have a reflecting area much smaller for a given concentration ratio and acceptance angle. 2) Between the mirror and the absorber, there is a large gap so that conduction losses are reduced. Convection losses can be reduced, too, if the absorber is enclosed within a glass tube. 3) It can be easily manufactured. Instead of seeking the shape of the mirrors for a given shape of the absorber, we have made the inverse statement of the problem, and we have obtained the optimal shapes of the absorbers with a prescribed acceptance angle, for parabolic mirrors, assuming that the intercept factor is unity, the mirrors are perfect, and the absorber surfaces are convex. The concentrator should be east-west oriented, and could be seasonal or monthly tilt adjusted. This concentrator could have many practical applications, such as fluid heating, steam generation, etc.

AN EASY APPROACH FOR ESTIMATING ABSORPTION LOSS IN ORGANIC THIN SOLID FILMS

1999 ◽  
Vol 08 (04) ◽  
pp. 519-525
Author(s):  
SHEN YUQUAN ◽  
LI ZHAO ◽  
ZHAO YUXIA ◽  
ZHAI JIANFENG ◽  
ZHOU JIAYUN ◽  
...  
Keyword(s):  
Spectroscopic Method ◽  
Optical Loss ◽  
Polymeric Films ◽  
Absorption Loss ◽  
Optical Losses ◽  
Thin Solid Films ◽  
Solid Films ◽  
Near Ir ◽  
Ir Spectroscopic

An UV-VIS-Near-IR spectroscopic method for determination of optical loss in organic/polymeric films has been suggested. The optical losses of two polyimide polymers with push-pull azobenzene chromophore attached were examined by this method and the data were calibrated by conventional optical method.

Synthesis of Photosensitive Organic-Inorganic Hybrid Polymers via Anhydrous Sol-Gel Process for Integrated Optics

2003 ◽  
Vol 780 ◽  
Author(s):  
Xinshi Luo ◽  
Congji Zha ◽  
Barry Luther-Davies
Keyword(s):  
Low Cost ◽  
Sol Gel ◽  
Optical Loss ◽  
Hybrid Polymer ◽  
Optical Losses ◽  
Hybrid Polymers ◽  
Inorganic Hybrid ◽  
Wide Range ◽  
Integrated Optical ◽  
Sol Gel Process

AbstractPhotosensitive organic-inorganic hybrid polymers were synthesised for integrated optical and optoelectronic devices by a non-hydrous sol-gel process of hydrolysis/condensation of 3-methacryloxypropyltrimethoxysilane (MPS), diphenyldimethoxysilane (DPhDMS), and zirconium isopropoxide (TPZ) with boric acid under anhydrous conditions. The methacryl groups of MPS are UVpolymerizable, which are suitable for low cost fabrication of waveguides with a “UV write/develop” process. The incorporation of DPhDMS and TPZ was found useful in reducing the optical loss and in enhancing the thermostability of the polymer. The refractive index of the hybrid polymer is tuneable from 1.4950 to 1.5360 by variation of the ratio among MPS, DPhDMS and TPZ. Optical characterisation showed that the material has low optical losses at the telecommunications windows (0.16 dB/cm at 1310 nm and 0.4 dB/cm at 1550nm). The hybrid polymer also showed a low birefringence (1.2×10-4), a large thermo-optic (TO) coefficient (-2.77 ×10-4), and an outstanding linearity of dn/dT in a wide range of temperature (from 25 °C to 200 °C). Waveguides forming ability for the hybrid polymer with UV imprinting was also demonstrated.

scholarly journals A Theoretical Study on Performance and Design Optimization of Linear Dielectric Compound Parabolic Concentrating Photovoltaic Systems

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2454 ◽  
Author(s):  
Guihua Li ◽  
Jingjing Tang ◽  
Runsheng Tang
Keyword(s):  
Solar Cells ◽  
Tilt Angle ◽  
Electricity Generation ◽  
Incidence Angle ◽  
Optical Loss ◽  
Diffuse Radiation ◽  
Transfer Model ◽  
Photovoltaic Systems ◽  
Operation Conditions ◽  
Solar Rays

To investigate solar leakage and effects of the geometry of linear dielectric compound parabolic concentrator with a restricted exit angle (DCPCθa/θe) on the performance of DCPCθa/θe -based photovoltaic systems (DCPVθa/θe), a three-dimensional radiation transfer model based on solar geometry and vector algebra is suggested. Analysis shows that the annual radiation loss due to leakage is sensitive to the geometry of DCPCs and tilt-angle adjustment strategy, and the optimal θe,opt for minimizing annual leakage is the one that makes the incidence angle of solar rays on the plane wall equal to the critical incidence angle for total internal reflection at solar-noon in solstices and days when tilt-angle adjustment from site latitude is made for DCPV with the aperture’s tilt-angle being yearly fixed, and adjusted two and four times, respectively. It is found that annual radiation leakage is considerable small, for DCPVs with θe < θe,opt, almost all leaked radiation comes from sky diffuse radiation, whereas for θe = 90°, most of leakage is attributed to direct sunlight. As compared to similar non-concentrating solar cells, more radiation arrives annually on solar cells of DCPVθa/θe at small angles thanks to refraction of radiation on the aperture, hence, under same operation conditions, the annual average photovoltaic efficiency of solar cells for concentrated radiation is even higher. Analysis also shows that the power increase of DCPVs, being much less than the geometric concentration of DCPCs (Ct), is mainly attributable to optical loss due to absorption of solar rays on the way to the solar cells, and the power loss due to leakage of radiation is not significant. From the point of annual electricity generation, for full DCPVs with a given θa, DCPVθa/90 are favorable, and for truncated DCPVs with given θa and Ct, DCPVs with θe < 90 are favorable; whereas from the point of contribution per unit volume of dielectric to the annual electricity generation, the situation is reversed.

Optical Losses in Ferroelectric Oxide Thin Films: Is There Light at the End of the Tunnel?

1994 ◽  
Vol 361 ◽  
Author(s):  
D. K. Fork ◽  
F. Armani-Leplingard ◽  
J. J. Kingston
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Optical Loss ◽  
Film Surface ◽  
Film Structure ◽  
Surface Scattering ◽  
Morphological Development ◽  
Optical Losses ◽  
Force Microscopy ◽  
Device Applications

ABSTRACTOptical losses are a barrier to use of ferroelectric waveguide thin films. Losses of about 2 dB/cm will reduce the efficiency of a frequency doubler by over 50%. Achieving losses on this order in conjunction with other essential film properties is difficult. The optical loss has several origins, including absorption, mode leakage, internal scattering and surface scattering. When the film surface morphology is accurately known, it is possible to estimate the surface scattering component of the loss. We have employed atomic force microscopy and computer modeling to compute, and correlate the optical loss as a function of film thickness and wavelength. The results suggest upper limits to the morphological roughness for various device applications. For lithium niobate films on sapphire which are intended to frequency double into the blue part of the spectrum, the optimal film thickness is about 400 nm and the RMS roughness is constrained below about 1.0 nm, with some weak dependence on grain size. Although present growth techniques do not appear to achieve this level of surface flatness intrinsically, an understanding of the morphological development of the film structure may lead to improvements.

Research on Gas Chamber of Reflective Optical Fiber Hydrogen Sensor

2014 ◽  
Vol 563 ◽  
pp. 145-148
Author(s):  
Xian Ling Deng ◽  
Chuan De Zhou ◽  
Liang Li ◽  
Kang Cheng
Keyword(s):  
Optical Fiber ◽  
Tilt Angle ◽  
Gas Flow ◽  
Optical Loss ◽  
Hydrogen Sensor ◽  
Sensor Sensitivity ◽  
Design Requirements ◽  
Gas Chamber

Gas chamber is one of the most important problems of the optical fiber hydrogen sensor, which directly affects the quality of the sensor sensitivity. For reflective optical fiber hydrogen sensor, the gas chamber was researched in this paper. First, the gas chamber structure and optical loss for reflective optical fiber hydrogen sensor was analyzed. Then design requirements to the gas chamber were discussed, including isolation the gas flow of reference part and measurement part, distance of the probe and the reflector, the tilt angle of the reflector. By using the gas chamber in the reflective optical fiber hydrogen sensor, it illustrates better effect.

Microstructure and optical loss in epitaxial (Pb, La)TiO3 thin films on (001) MgO

1998 ◽  
Vol 13 (4) ◽  
pp. 995-1001 ◽  
Author(s):  
Young Min Kang ◽  
Sunggi Baik
Keyword(s):  
Thin Films ◽  
Smooth Surface ◽  
Optical Loss ◽  
Optical Losses ◽  
Coupling Technique ◽  
Optical Propagation ◽  
Domain Boundaries ◽  
Propagation Losses ◽  
La Substitution ◽  
Surface Morphologies

Surface morphologies and microstructures of epitaxial (Pb1−xLax)TiO3 (PLT, x = 0.00, 0.08, 0.16, and 0.24) thin films grown on (001) MgO have been investigated using SEM, AFM, and TEM. Surface roughness of PLT films varies severely with La concentration. For 0.08La-PLT film, very smooth surface has been achieved with 9.3 Å of RMS roughness. 0.00La- and 0.08La-PLT films show 90° domain structure, and periodic dimension of the domain is reduced by La substitution. 0.16La- and 0.24La-PLT films show the presence of triangular grains, causing rough surface and poor crystal quality. However, they are distributed uniformly in 0.16La-PLT film while agglomerated in 0.24La-PLT film. Optical propagation losses of PLT films measured by prism coupling technique were 22.3, 6.0, 11.4, and 20.7 dB/cm for x = 0.00, 0.08, 0.16, and 0.24, respectively. Such a variation in optical losses seemed to be due to the surface morphology and abundance of domain boundaries that change continuously as a function of La concentration in epitaxial PLT thin films.

scholarly journals Assessing the parameters modulating optical losses of iron oxide nanoparticles under near infrared irradiation

2021 ◽  
Author(s):  
Claudia Lozano-Pedraza ◽  
Elena Plaza-Mayoral ◽  
Ana Espinosa ◽  
Begoña Sot ◽  
Aida Serrano ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Near Infrared ◽  
Optical Loss ◽  
Oxide Nanoparticles ◽  
Infrared Irradiation ◽  
Optical Losses

Heating mediated by iron oxide nanoparticles subjected to near infrared irradiation has recently gained lots of interest. The high optical loss values reported in combination with the optical technologies already...

scholarly journals Dependence of optical attenuation on radiation wavelength and waveguide geometry in copper-coated optical fibers

2020 ◽  
Vol 238 ◽  
pp. 11013
Author(s):  
Pavel Cherpak ◽  
Renat Shaidullin ◽  
Oleg Ryabushkin
Keyword(s):  
Optical Fibers ◽  
Near Infrared ◽  
Optical Loss ◽  
Single Mode ◽  
Optical Losses ◽  
Radiation Losses ◽  
Optical Attenuation ◽  
Novel Approach ◽  
Laser Sources

We demonstrate a novel approach to the determination of optical loss coefficients in metal-coated fibers in a 0.4-1.9 μm wavelength range. It is based on measuring the change of temperature-dependent electrical resistance of the metal coating caused by laser radiation transmitted through the fiber. A number of single-mode and multimode metallized fibers were investigated using several laser sources operating in visible and near infrared ranges. The spectral dependencies of optical losses of copper-coated fibers were experimentally obtained. The region that corresponds to the minimum optical losses is located near 1 μm wavelength. The increase of radiation losses in 1.5-1.9 μm region is much steeper compared to polymer-coated fibers.

Sign in / Sign up

Export Citation Format

Share Document