scholarly journals Study on Concentrating Characteristics of a Solar Parabolic Dish Concentrator within High Radiation Flux

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Qianjun Mao ◽  
Liya Zhang ◽  
Hongjun Wu
Keyword(s):  
Focal Plane ◽  
Flux Distribution ◽  
Radiation Flux ◽  
Focal Length ◽  
Thermal Conversion ◽  
High Radiation ◽  
Equal Area ◽  
Future Design ◽  
Parabolic Dish ◽  
Parabolic Dish Concentrator

Concentrating characteristics of the sunlight have an important effect on the optical-thermal conversion efficiency of solar concentrator and the application of the receiver. In this paper, radiation flux in the focal plane and the receiver with three focal lengths has been investigated based on Monte Carlo ray-tracing method. At the same time, based on the equal area-height and equal area-diameter methods to design four different shape receivers and numerical simulation of radiation flux distribution characteristics have also been investigated. The results show that the radiation flux in the focal plane increases with decreasing of the focal length and the diameter of the light spot increases with increasing of the focal length. The function of the position with a maximum of radiation flux has been obtained according to the numerical results. The results also show that the radiation flux distribution of cylindrical receiver has the best performance in all four receivers. The results can provide a reference for future design and application of concentrating solar power.

Flux Density Distribution in the Focal Region of a Solar Concentrator System

1991 ◽  
Vol 113 (2) ◽  
pp. 112-116 ◽  
Author(s):  
M. Schubnell ◽  
J. Keller ◽  
A. Imhof
Keyword(s):  
Density Distribution ◽  
Flux Density ◽  
Ray Tracing ◽  
Radiation Flux ◽  
Focal Length ◽  
Solar Furnace ◽  
Focal Region ◽  
The Sun ◽  
Parabolic Dish ◽  
Flux Density Distribution

In high temperature solar energy applications highly concentrating optical systems, such as, e.g., parabolic dishes, achieve typical radiation flux densities >2 MW/m2. In order to investigate thermo and photochemical reactions at temperatures >1500 K and radiation flux densities >2 MW/m2 a solar furnace was built at Paul Scherrer Institute (PSI). This furnace is a two-stage concentrator. The first stage is a prefocusing glass heliostat with a focal length of 100 m. The second stage is a highly concentrating parabolic dish with a focal length of 1.93 m. To design experiments to be carried out in the focal region of the parabolic dish, the radiation flux as well as its density distribution have to be known. This distribution is usually measured by radiometric methods. However, these methods are generally rather troublesome because of the high temperatures involved. In this paper we present a simple method to estimate the characteristic features of the radiation flux density distribution in the focal region of a concentrator system. It is well known from solar eclipses that the mean angular diameter of the moon is almost equal to that of the sun (9.1 mrad versus 9.3 mrad). Hence, the lunar disk is well suited to be used as a light source to investigate the flux distribution in a solar furnace. Compared to the sun the flux density is reduced by 4·105 and the flux density distribution can be inspected on a sheet of paper located in the plane of interest, e.g., the focal plane. This distribution was photographed and analyzed by means of an image processing system. The density distribution was also simulated using a Monte Carlo ray tracing program. Based on this comparison, and on further ray tracing computations, we show that the peak flux density decreases from 8.9 MW/m2 in December to values below 4 MW/m2 in June and the net radiation flux from 25 kW to 15 kW, respectively.

Design and Construction of a Parabolic Dish in Mexico

Solar Energy ◽  
2004 ◽  
Author(s):  
Carlos Ramos Berumen ◽  
Rafael Rami´rez Beni´tez ◽  
Javier Lagunas Mendoza ◽  
Jorge Huacuz Villamar ◽  
Ivan Vilar Rojas ◽  
...  
Keyword(s):  
Material Selection ◽  
Focal Length ◽  
Tracking System ◽  
Control Unit ◽  
Final Design ◽  
Parabolic Dish ◽  
Design Characteristics ◽  
Parabolic Dish Concentrator ◽  
Reflecting Surface ◽  
And Control

A parabolic dish concentrator for electricity generation is currently under development at the Instituto de Investigaciones Ele´ctricas (IIE) of Mexico, a government-owned research organization. The concentrator is 7.5 meters in diameter with focal length to diameter ratio of 0.6. The reflective surface consists of 12 facets made of fiberglass with a reflecting surface made of aluminum sheet with a solar reflectance of 86%. The system will use a 9 kW Stirling engine to produce electricity from concentrated solar radiation. The paper describes preliminary and final design characteristics of the parabolic dish structure. Criteria for facet design, material selection, and structural configuration are reviewed. A detail explanation of tooling, substrate preparation and facets assembly is also presented. The key features and requirements of the tracking system, Stirling motor and control unit are also described.

Design of a New 45 kWe High-Flux Solar Simulator for High-Temperature Solar Thermal and Thermo-Chemical Research

2010 ◽  
Author(s):  
Katherine R. Krueger ◽  
Jane H. Davidson ◽  
Wojciech Lipin´ski
Keyword(s):  
High Temperature ◽  
Focal Plane ◽  
Flux Distribution ◽  
Solar Thermal ◽  
Optimized Design ◽  
High Flux ◽  
Chemical Research ◽  
Solar Simulator ◽  
Peak Flux ◽  
The Common

In this paper, we present a systematic procedure to design a solar simulator for high-temperature concentrated solar thermal and thermo-chemical research. The 45 kWe simulator consists of seven identical radiation units of common focus, each comprised of a 6.5 kWe xenon arc lamp close-coupled to a precision reflector in the shape of a truncated ellipsoid. The size and shape of each reflector is optimized by a Monte Carlo ray tracing analysis to achieve multiple design objectives, including high transfer efficiency of radiation from the lamps to the common focal plane and desired flux distribution. Based on the numerical results, the final optimized design will deliver 7.5 kW over a 6-cm diameter circular disc located in the focal plane, with a peak flux approaching 3.7 MW/m2.

Improved Alignment Technique for Dish Concentrators

Solar Energy ◽  
2003 ◽  
Author(s):  
Charles E. Andraka ◽  
Richard B. Diver ◽  
K. Scott Rawlinson
Keyword(s):  
Focal Length ◽  
Electric Energy ◽  
Parabolic Systems ◽  
Companion Paper ◽  
Quantitative Information ◽  
Key Factors ◽  
Look Back ◽  
Parabolic Dish ◽  
The Individual

Parabolic dish concentrators have shown significant promise of generating competitive electric energy for grid and off-grid applications. The efficiency of a dish-electric system is strongly affected by the quality of the concentrator optics. Most parabolic systems consist of a number of facets mounted to a support structure in an approximate parabolic arrangement, where the individual facets have spherical or parabolic optical shapes. The individual facets must be accurately aligned because improper alignment can compromise performance or create hot spots that can reduce receiver life. A number of techniques have been used over the years to align concentrator facets. In the Advanced Dish Development System (ADDS) project, a color look-back alignment approach that accurately aligns facets (mirror panels) and in addition indicates quantitative information about the focal length was developed. Key factors influencing the alignment, some of which had very large effects on the quality of the alignment, were also identified. The influence of some of the key factors was characterized with a flux mapping system on the second-generation ADDS concentrator. Some of these factors also affect other alignment approaches. The approach was also successfully applied to two other concentrators with differing facet arrangements. Finally, we have extended the method to a 2-f approach that eliminates the need for a distant line-of-sight to the dish and permits alignment at near vertical dish attitudes. In this paper, we outline the color look-back alignment approach, discuss the key alignment factors and their effect on flux distribution, and discuss extensions to non-gore dishes. A companion paper discusses the 2-f color alignment approach in detail.

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