Optical performance of a hybrid compound parabolic concentrator and parabolic trough concentrator system for dual concentration

2021 ◽  
Vol 47 ◽  
pp. 101538
Author(s):  
Sridhar Sripadmanabhan Indira ◽  
Chockalingam Aravind Vaithilingam ◽  
Ramsundar Sivasubramanian ◽  
Kok-Keong Chong ◽  
R. Saidur ◽  
...  
Author(s):  
Tejas U. Ulavi ◽  
Jane H. Davidson ◽  
Tim Hebrink

The technical performance of a non-tracking hybrid PV/T concept that uses a wavelength selective film is modeled. The wavelength selective film is coupled with a compound parabolic concentrator to reflect and concentrate the infrared portion of the solar spectrum onto a tubular absorber while transmitting the visible portion of the spectrum to an underlying thin-film photovoltaic module. The optical performance of the CPC/selective film is obtained through Monte Carlo Ray-Tracing. The CPC geometry is optimized for maximum total energy generation for a roof-top application. Applied to a rooftop in Phoenix, Arizona USA, the hybrid PV/T provides 20% more energy compared to a system of the same area with independent solar thermal and PV modules, but the increase is achieved at the expense of a decrease in the electrical efficiency from 8.8% to 5.8%.


Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 128 ◽  
Author(s):  
Majedul Islam ◽  
Prasad Yarlagadda ◽  
Azharul Karim

While the circular shape is currently the proven optimum design of the energy collection element (ECE) of a parabolic trough collector, that is yet to be confirmed for parabolic trough concentrating collectors (PTCCs) like trough concentrating photovoltaic collectors and hybrid photovoltaic/thermal collectors. Orientation scheme of the ECE is expected to have significant effect on the optical performance including the irradiance distribution around the ECE and the optical efficiency, and therefore, on the overall energy performance of the PTCC. However, little progress addressing this issue has been reported in the literature. In this study, a thorough investigation has been conducted to determine the effect of the orientation schemes of ECE on the optical performance of a PTCC applying a state-of-the-art Monte Carlo ray tracing (MCRT) technique. The orientation schemes considered are a flat rectangular target and a hollow circular, semi-circular, triangular, inverted triangular, rectangular and rectangle on semi-circle (RSc). The effect of ECE defocus, Sun tracking error and trough rim angle on the optical performance is also investigated. The MCRT study reveals that the ECE orientation schemes with a curved surface at the trough end showed much higher optical efficiency than those with a linear surface under ideal conditions. ECEs among the linear surface group, the inverted triangular orientation exhibited the highest optical efficiency, whereas the flat and triangular ones exhibited the lowest optical efficiency, and the rectangular one was in between them. In the event of defocus and tracking errors, a significant portion of the concentrated light was observed to be intercepted by the surfaces of the rectangular and RSc ECEs that are perpendicular to the trough aperture. This is an extended version of a published work by the current authors, which will help to design an optically efficient ECE for a parabolic trough concentrating collector.


Author(s):  
J. Kathleen Stynes ◽  
Benjamin Ihas

As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Akiba Segal ◽  
Michael Epstein

A central solar plant based on beam-down optics is composed of a field of heliostats, a tower reflector (hyperboloid mirror), and a ground receiver interfaced at its aperture with one or a cluster of secondary concentrators (compound parabolic concentrator). In previous publications, a method was presented, illustrating the correlation between the tower reflector position and its size on one hand and the geometry, dimensions, and reflective area of the secondary concentrator on the other hand, both related to the heliostat field reflective area. Obviously, when one wishes to reduce the size of a tower reflector by locating it closer to the upper focal point, the image created at the lower focus will be broader, resulting in a larger secondary ground concentrator. The present paper describes a method for substantial decrease in the dimensions of the ground secondary concentrator cluster (and, implicitly, the concentrator's area) via truncation and some geometrical corrections without significant sacrifice of the optical performance. This offers a method for cost effective design of future central solar plants, utilizing the beam-down optics.


Author(s):  
Kenneth Biggio ◽  
Rachel Backes ◽  
Jennifer Crawford

The thermal performance of parabolic trough concentrating solar collectors depends on both the structural and optical characteristics of the design. In order to reduce the cost of energy, advanced concentrating structures must significantly reduce the cost of collectors while maintaining good optical performance. This paper discusses a Finite Element Ray Tracer (FERT) that has been developed specifically to support the commercial design process. This is achieved by tying the whole of the support structure directly to its optical effects. Consequently, the optical performance metrics go beyond the typical reflector slope error RMS or average intercept factor to present the designer with spatially resolved analysis of localized performance. By incorporating this analytical method into the structural design process, collector cost and performance can be balanced efficiently and rapidly, allowing for an accelerated design period. At times, this insight has driven better, albeit unexpected, design decisions. The paper presents an overview of the development process that Abengoa R&D uses to take advantage of its analytical optical analysis capability throughout all phases of a project, as well as a review of its implementation. A selection of case studies is also presented to illustrate how FERT enables the designer to identify local areas of concern, diagnose the cause, and quickly develop possible redesign strategies. Finally, the significance of various parameters within the ray tracer are discussed.


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