Experimental and numerical investigations of solar flux density distribution over flat plate receiver of model heliostat system
25 Nov 2020-Journal of Thermal Engineering (Journal of Thermal Engineering)-Vol. 6, Iss: 6, pp 312-322
TL;DR: In this article, a prototype model of the central receiver system consisting of ganged heliostats has been constructed and installed at Pune, Maharashtra, India, where a thermocouple method was used to evaluate the total energy focused by the model helIostat system on a flat receiver.
Abstract: The flux density distribution and the temperature of the receiver are important parameters to assess the net thermal energy of any Solar Power Concentrator. In the present work, a heliostat field utilizing ganged type of heliostats for process heating application has been designed. A prototype model of the central receiver system consisting of ganged heliostats has been constructed and installed at Pune, Maharashtra, India. A thermocouple method was used to evaluate the total energy focused by the model heliostat system on a flat receiver. The flux density distribution was validated with the ray tracing simulation software ‘SolTrace’. The simulated flux density distribution was found to be in agreement with the measured one for a surface normal error of 10 milliradian. A heliostat field having 100 m2 total mirror area was designed in the north south cornfield layout. This heliostat field was simulated in ‘SolTrace’ software by considering the surface normal errors as 10 milliradian and the total energy gain was estimated. For the purpose of simulation to investigate the solar flux falling on the receiver, four days of the year were selected. It includes the March equinox, summer solstice, September equinox, and winter solstice.
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01 Feb 1993
TL;DR: Two heliostats representing the state-of-the-art in glass-metal designs for central receiver (and photovoltaic tracking) applications were tested and evaluated at the National Solar Thermal Test Facility in Albuquerque, New Mexico from 1986 to 1992.
Abstract: Two heliostats representing the state-of-the-art in glass-metal designs for central receiver (and photovoltaic tracking) applications were tested and evaluated at the National Solar Thermal Test Facility in Albuquerque, New Mexico from 1986 to 1992. These heliostats have collection areas of 148 and 200 m{sup 2} and represent low-cost designs for heliostats that employ glass-metal mirrors. The evaluation encompassed the performance and operational characteristics of the heliostats, and examined heliostat beam quality, the effect of elevated winds on beam quality, heliostat drives and controls, mirror module reflectance and durability, and the overall operational and maintenance characteristics of the two heliostats. A comprehensive presentation of the results of these and other tests is presented. The results are prefaced by a review of the development (in the United States) of heliostat technology.
4 citations
01 Jun 2021
2 citations
TL;DR: In this article, a flat receiver plate was experimentally investigated with a small scale solar central receiver system in order to study the effect of receiver temperature and the flux distribution on the receiver plate.
Abstract: The central receiver concept for solar energy concentration and collection is based on a field of sun-tracking mirrors (heliostats) that reflect the incident sunshine to a receiver (boiler) at the top of a centrally located tower [1]. A solar central receiver system is used for medium temperature process heating aplication or in solar thermal power plant. A flat receiver plate was experimentally investigated with a small scale solar central receiver system in order to study the effect of receiver temperature and the flux distribution on the receiver plate. The receiver surface temperature increases with increase in intensity of beam radiation, concentration ratio, ambient temperature and decreases with increase in wind speed. Flux density distribution at focal region of concentrator can be estimated, if the temperature on focal region is measured. In the present work thermocouple method is used to estimate the flux density distribution on the flat receiver plate. The variation of the temperature on the receiver plate is estimated experimentally by varying the number of heliostats which are focused on the receiver plate. It is seen that for all the cases of heliostat numbers the radiation reflected from the heliostat field on the receiver surface forms a variation of flux density distribution. The peak flux is obtained at a single point on the receiver surface. For the small central receiver system of 7 heliostat the peak flux value is found around 4110 W/m 2 (± 2%) and the average value of flux of the receivr plate is 1984 W/m 2 (± 2%).
2 citations
TL;DR: In this paper , a simple methodology has been proposed to design a central receiver for CRS consisting of ganged heliostat system using SolTrace 3.1.0 software.
Abstract: Concentrated solar power (CSP) technology has become a promising technique for harnessing the sun’s energy. Ganged heliostat system, also called as central receiver system (CRS), a type of CSP system that uses a field of radially distributed heliostats (mirrors), which track the position of the sun in two axes and focus the sunlight on the centrally placed receiver. Heliostats are used to concentrate solar rays on the receiver, producing a huge amount of energy which can later get converted into electricity or heat. The receiver is kept at a sufficient height to absorb maximum reflected rays. In the present work, a numerical analysis method is used to optimize receiver design parameters such as receiver size, its position in horizontal and vertical planes, and to predict the heat flux intensity at the receiver surface. However, there is no direct method to decide these parameters and often results in a loss of time while optimizing them. In this research paper, a simple methodology has been proposed to design a central receiver for CRS consisting of ganged heliostat system using SolTrace 3.1.0 software. This method is effective in determining the size, the position of the receiver and heat flux distribution at the receiver surface in the initial phase of receiver system design.
References
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TL;DR: In this paper, the authors presented a methodology to project the flux distribution from the image plane into the panels of any central receiver in solar power tower plants, which solved the distorted spot found in actual receivers.
122 citations
"Experimental and numerical investig..." refers methods in this paper
...[22] have given a methodology to project the flux distribution from the image plane into the panels of any central receiver in Solar Power Tower plants....
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TL;DR: In this article, a parametric analysis for a medium to large size (290-500 MW th receiver thermal power) central receiver plant considering the present market trends is presented, and the analysis is divided in 4 steps: • Size and location analysis: for a small to medium size central receiver power plant, three turbine power and three different locations that are involved in the development of power tower plants, have been analyzed to assess the impact over the design characteristics of the solar field and receiver sub-systems and over the levelized electricity cost.
103 citations
"Experimental and numerical investig..." refers background in this paper
...[11] evaluated the performance of medium to large size central receiver plants based on size and location analysis, technology analysis, storage analysis, components cost analysis....
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TL;DR: A flux mapping system able to measure the flux distribution of dish/Stirling systems in planes perpendicular to the optical axis was built and operated at the Plataforma Solar de Almeria (PSA) as discussed by the authors, which uses the indirect measuring method with a watercooled Lambertian target placed in the beam path and a CCD-camera mounted on the concentrator taking images of the brightness distribution of the focal spot.
Abstract: A flux mapping system able to measure the flux distribution of dish/Stirling systems in planes perpendicular to the optical axis was built and operated at the Plataforma Solar de Almeria (PSA). It uses the indirect measuring method with a water-cooled Lambertian target placed in the beam path and a CCD-camera mounted on the concentrator taking images of the brightness distribution of the focal spot. The calibration is made by calculating the total power coming from the dish and relating it to the integrated gray value over the whole measurement area. The system was successfully operated in a DISTAL II stretched membrane dish and in the new EURODISH in order to characterize their beams and improve the flux distribution on their receivers.Copyright © 2002 by ASME
99 citations
"Experimental and numerical investig..." refers methods in this paper
...[5] also used the CCD camera and image analysis software without a flux gauge for measuring the flux density distribution from a dish concentrator....
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01 Feb 1993
TL;DR: Two heliostats representing the state-of-the-art in glass-metal designs for central receiver (and photovoltaic tracking) applications were tested and evaluated at the National Solar Thermal Test Facility in Albuquerque, New Mexico from 1986 to 1992 as mentioned in this paper.
Abstract: Two heliostats representing the state-of-the-art in glass-metal designs for central receiver (and photovoltaic tracking) applications were tested and evaluated at the National Solar Thermal Test Facility in Albuquerque, New Mexico from 1986 to 1992. These heliostats have collection areas of 148 and 200 m{sup 2} and represent low-cost designs for heliostats that employ glass-metal mirrors. The evaluation encompassed the performance and operational characteristics of the heliostats, and examined heliostat beam quality, the effect of elevated winds on beam quality, heliostat drives and controls, mirror module reflectance and durability, and the overall operational and maintenance characteristics of the two heliostats. A comprehensive presentation of the results of these and other tests is presented. The results are prefaced by a review of the development (in the United States) of heliostat technology.
64 citations
TL;DR: In this paper, the optical performance of a static 3-D elliptical hyperboloid concentrator (EHC) using ray tracing software was evaluated, and the overall performance of the concentrator was assessed based on the acceptance angle, effective concentration ratio and optical efficiency.
60 citations
"Experimental and numerical investig..." refers methods in this paper
...[21] used a ray tracing software to evaluate the optical performance of a static 3-D Elliptical Hyperboloid Concentrator (EHC) using ray tracing software....
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