Theoretical Bases of the Use of Solar Concentrating Modules With Louvered Heliostats

2021 ◽  
pp. 44-73
Keyword(s):  
Solar Radiation ◽  
Concentration Ratio ◽  
Functional Relationship ◽  
Three Dimensional ◽  
Parabolic Cylinder ◽  
The Sun ◽  
Mirror Surface ◽  
Solar Concentrator ◽  
Dimensional Problem ◽  
Angular Aperture

A functional relationship was obtained linking the position of the Sun, the step of the mirror lamellae of the heliostat, and their orientation to ensure zero blocking and shading losses in the louvered heliostat. Based on the consideration of a three-dimensional problem, the algorithm for calculating the passage of sunlight through the mirror surface of the lamellae and parabolic cylinder allows calculating the flux of solar radiation on the receiving surface of the solar concentrator. An algorithm for controlling lamellar heliostat mirror lamellas has been developed that significantly increases the efficiency of a solar concentrator—using a louvre heliostat with a constant lamella pitch is equivalent to increasing the angular aperture of the concentrator from 26° to 70° without reducing the concentration ratio.

The Overview of Basic Types and Characteristics of Solar Concentrating Modules With Louvered Heliostats

2021 ◽  
pp. 1-43
Keyword(s):  
Solar Radiation ◽  
Radiation Flux ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Solar Concentrator ◽  
Dimensional Problem ◽  
Solar Concentrators ◽  
Solar Radiation Flux ◽  
Analytical Review ◽  
Photovoltaic Technologies

The principles of construction and operation of the main concentrating systems, including non-followable modules, are reviewed, and the work of the concentrators is analyzed. An analytical review of modern facade-integrated photovoltaic technologies was carried out, and their classification was given. The known methods for calculating a flat (two-dimensional) scheme for passing the sun's rays through a louvered heliostat make it impossible to assess the real effectiveness of using louvered heliostats with non-tracking solar concentrators, which makes it necessary to consider the practically important three-dimensional problem of calculating the solar radiation flux on the receiving surface of an unfollowing parabolic-cylindrical solar concentrator with louver heliostat.

Results of an Experimental Research of a Solar Concentrating Module With Louvered Heliostats

2021 ◽  
pp. 104-126
Keyword(s):  
Experimental Data ◽  
Information Processing ◽  
Solar Radiation ◽  
Computer Program ◽  
Relative Error ◽  
Experimental Research ◽  
Automatic Measurement ◽  
Parabolic Cylinder ◽  
Mirror Surface ◽  
Solar Concentrator

The developed system of automatic measurement of the main parameters of a solar concentrating module with PV, PVT, and heat receivers allows you to save time during information processing, to obtain data on the dynamics of the processes in the solar concentrating module with the required measurement periodicity. The developed algorithm for calculating the passage of sunlight through the mirror surface of the lamellae and the parabolic cylinder, implemented as a computer program, allows calculating the flow of solar radiation on the receiving surface of the solar concentrator with a relative error of not more than 5%, which is confirmed by experimental data.

Energy Balances on a Parabolic Cylinder Solar Collector

1962 ◽  
Vol 84 (1) ◽  
pp. 24-32 ◽  
Author(s):  
G. O. G. Lof ◽  
D. A. Fester ◽  
J. A. Duffie
Keyword(s):  
Experimental Data ◽  
Solar Radiation ◽  
Solar Collector ◽  
Concentration Ratio ◽  
Meteorological Variables ◽  
Parabolic Cylinder ◽  
Solar Collectors ◽  
Cylindrical Reflector ◽  
Energy Balances ◽  
Focal Zone

A technique for optimizing the design of focusing solar collectors was developed through a detailed study of the energy balances for a parabolic-cylindrical reflector with tubular receivers of three diameters. Experimental data for concentration ratios of 10 to 22.5 and surface temperatures of 88 to 353 deg F are presented. Receiver temperature, meteorological variables (including solar radiation), and distribution of reflected radiation in the focal zone of the reflector were measured and correlated so as to permit optimization of concentration ratio.

Three-Dimensional Analysis of a Concentrated Solar Flux

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
David Riveros-Rosas ◽  
Marcelino Sánchez-González ◽  
Claudio A. Estrada
Keyword(s):  
Thermal Stress ◽  
Solar Radiation ◽  
Computer Program ◽  
Ray Tracing ◽  
Solar Irradiance ◽  
Radiation Flux ◽  
Three Dimensional ◽  
Mirror Surface ◽  
Concentrated Solar Radiation ◽  
Focal Zone

In order to improve the durability of receivers used in solar concentrating systems, it is necessary to minimize thermal stress during their operation. A possible way to do that is to design receivers in which the radiative flux density is homogeneous at the surface. For this reason, a detailed 3D study has been carried out for the distribution of concentrated solar radiation in the focal zone of a parabolic concentrator. A computer program has been developed to obtain isosurfaces of solar irradiance and achieve a homogeneous radiation flux on the receiver surface. The algorithm of the program proposes a methodology to obtain flux isosurfaces for a great variety of optical configurations. The effect of the optical errors on the mirror surface has been studied, as well as the effect of the shape of the mirror, e.g., round, square, or faceted. The numerical calculations were made using the convolution ray tracing technique.

scholarly journals Stretchable micro-scale concentrator photovoltaic module with 15.4% efficiency for three-dimensional curved surfaces

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Daisuke Sato ◽  
Taizo Masuda ◽  
Kenji Araki ◽  
Masafumi Yamaguchi ◽  
Kenichi Okumura ◽  
...  
Keyword(s):  
Concentration Ratio ◽  
Power Conversion ◽  
Three Dimensional ◽  
Thin Film Solar Cells ◽  
Photovoltaic Module ◽  
Silicon Compound ◽  
Curved Surfaces ◽  
Power Sources ◽  
Micro Scale ◽  
Module Design

AbstractStretchable photovoltaics are emerging power sources for collapsible electronics, biomedical devices, and buildings and vehicles with curved surfaces. Development of stretchable photovoltaics are crucial to achieve rapid growth of the future photovoltaic market. However, owing to their rigidity, existing thin-film solar cells based predominantly on silicon, compound semiconductors, and perovskites are difficult to apply to 3D curved surfaces, which are potential real-world candidates. Herein, we present a stretchable micro-scale concentrator photovoltaic module with a geometrical concentration ratio of 3.5×. When perfectly fitted on a 3D curved surface with a sharp curvature, the prototype module achieves an outdoor power conversion efficiency of 15.4% and the daily generated electricity yield improves to a maximum of 190% relative to a non-concentration stretchable photovoltaic module. Thus, this module design enables high areal coverage on 3D curved surfaces, while generating a higher electricity yield in a limited installation area.

Mathematical Theory of Transversally Isotropic Shells of Arbitrary Thickness at Static Load

2019 ◽  
Vol 968 ◽  
pp. 496-510
Author(s):  
Anatoly Grigorievich Zelensky
Keyword(s):  
Mathematical Theory ◽  
Three Dimensional ◽  
Nonlinear Problems ◽  
Theory Of Elasticity ◽  
Elastic Plates ◽  
Dimensional Problem ◽  
Boundary Problems ◽  
Complex Boundary ◽  
Plates And Shells ◽  
Basic Equations

Classical and non-classical refined theories of plates and shells, based on various hypotheses [1-7], for a wide class of boundary problems, can not describe with sufficient accuracy the SSS of plates and shells. These are boundary problems in which the plates and shells undergo local and burst loads, have openings, sharp changes in mechanical and geometric parameters (MGP). The problem also applies to such elements of constructions that have a considerable thickness or large gradient of SSS variations. The above theories in such cases yield results that can differ significantly from those obtained in a three-dimensional formulation. According to the logic in such theories, the accuracy of solving boundary problems is limited by accepted hypotheses and it is impossible to improve the accuracy in principle. SSS components are usually depicted in the form of a small number of members. The systems of differential equations (DE) obtained here have basically a low order. On the other hand, the solution of boundary value problems for non-thin elastic plates and shells in a three-dimensional formulation [8] is associated with great mathematical difficulties. Only in limited cases, the three-dimensional problem of the theory of elasticity for plates and shells provides an opportunity to find an analytical solution. The complexity of the solution in the exact three-dimensional formulation is greatly enhanced if complex boundary conditions or physically nonlinear problems are considered. Theories in which hypotheses are not used, and SSS components are depicted in the form of infinite series in transverse coordinates, will be called mathematical. The approximation of the SSS component can be adopted in the form of various lines [9-16], and the construction of a three-dimensional problem to two-dimensional can be accomplished by various methods: projective [9, 14, 16], variational [12, 13, 15, 17]. The effectiveness and accuracy of one or another variant of mathematical theory (MT) depends on the complex methodology for obtaining the basic equations.

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.

Effect of Solar Brightness Profiles on the Performance of Parabolic Concentrating Collectors

2009 ◽  
Author(s):  
Daniel J. Chapman ◽  
Diego A. Arias
Keyword(s):  
Analytical Methods ◽  
Meteorological Data ◽  
Uncertainty Propagation ◽  
Gaussian Function ◽  
Analytical Models ◽  
The Sun ◽  
Solar Concentrator ◽  
Optical Performance ◽  
Optical Surface ◽  
Solar Brightness

Solar brightness profiles were used to model the optical performance of a parabolic linear solar concentrator. A sensitivity analysis of the sun size on collector performance was completed using analytical methods. Ray traces were created for solar brightness profiles having circumsolar ratios from 0–40%, slope errors of the optical surface from 2–5 mrads, and angles of incidence varying from 0–60 degrees. Using typical meteorological data for two locations, the optical performance was calculated and averaged over a year. Intercept factors of these simulations were compared to simpler analytical models that cast the sun shape as a Gaussian function. Results showed that collector performance is relatively insensitive to solar profile, and that using a representative Gaussian solar profile will tend to underestimate collector performance compared to using exact weighted solar profiles by about 1%. This difference is within the uncertainty propagation of the intercept factor calculated with analytical methods.

scholarly journals The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations

2021 ◽  
Author(s):  
Yixiao Zhou ◽  
Thomas Nordlander ◽  
Luca Casagrande ◽  
Meridith Joyce ◽  
Yaguang Li ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Three Dimensional ◽  
Quantitative Relationship ◽  
Stellar Atmospheres ◽  
Spectral Lines ◽  
Wavelength Shift ◽  
The Sun ◽  
Theoretical Derivation ◽  
Velocity Amplitude ◽  
Good Agreement

Abstract We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numerical simulations of stellar atmospheres. We present a theoretical derivation as proof of concept for our method. We perform realistic spectral line formation calculations to quantify the ratio between luminosity and radial velocity amplitude for two case studies: the Sun and the red giant ε Tau. Luminosity amplitudes are computed based on the bolometric flux predicted by 3D simulations with granulation background modelled the same way as asteroseismic observations. Radial velocity amplitudes are determined from the wavelength shift of synthesized spectral lines with methods closely resembling those used in BiSON and SONG observations. Consequently, the theoretical luminosity to radial velocity amplitude ratios are directly comparable with corresponding observations. For the Sun, we predict theoretical ratios of 21.0 and 23.7 ppm/[m s−1] from BiSON and SONG respectively, in good agreement with observations 19.1 and 21.6 ppm/[m s−1]. For ε Tau, we predict K2 and SONG ratios of 48.4 ppm/[m s−1], again in good agreement with observations 42.2 ppm/[m s−1], and much improved over the result from conventional empirical scaling relations which gives 23.2 ppm/[m s−1]. This study thus opens the path towards a quantitative understanding of solar-like oscillations, via detailed modelling of 3D stellar atmospheres.

Sign in / Sign up

Export Citation Format

Share Document