Tiong-Keat Yew

Optical Characterization of Nonimaging Planar Concentrator for the Application in Concentrator Photovoltaic System

The design and construction of miniature prototype of nonimaging planar concentrator, which is capable of producing much more uniform spatial irradiance and reasonably high concentration ratio, were presented in the previous paper. In this paper, we further explore the optical characteristics of the new concentrator that is specially designed to be incorporated in concentrator photovoltaic systems. For this study, we have carried out a comprehensive analysis via numerical simulation based on all the important design parameters, i.e., array of facet mirrors, f/D ratio, receiver size, and the effect of suntracking error, which lead to the overall optical performance of the new concentrator.

Solar flux distribution analysis of Non-Imaging Planar Concentrator for the application in concentrator photovoltaic system

The design and construction of Non-Imaging Planar Concentrator (NIPC), capable of producing much more uniform spatial irradiance and reasonably high concentration ratio, have been presented in our previous research paper. In this study, we would carry out a comprehensive analysis through the numerical simulation on solar flux distribution at the target by considering all the important criteria to improve the overall performance of dense-array concentrator photovoltaic system, which are the maximum solar concentration, uniform illumination area, spillage loss etc. Maximum solar concentration ratio and percentage of energy in uniform illumination area are plotted for different cases. In general, the simulated results have shown a reasonably good uniformity of solar irradiance and high concentration ratio at the receiver plane.

Novel Optical Scanner Using Photodiodes Array for Two-Dimensional Measurement of Light Flux Distribution

An optical scanner, also known as a flux mapping system, capable of acquiring a flux distribution pattern of a light source on a 2-D flat surface, has been designed and constructed. The novel optical scanner can measure the light flux distribution at high resolution with fewer sensors in a relatively short amount of time, and it can be used for precise calibration of any light source. The design of the optical scanner consisted of a single row of photodiodes with fixed distances that can scan and acquire flux distribution data in the 2-D measurement plane. In our prototype design of the novel optical scanner, 25 photodiodes with a photosensitive area of 1 cm2 each were arranged in a single row and fixed to an aluminum holder. The resulting scanner was fast enough to perform scanning and recording of light irradiance over a test plane area of 1125 cm2 within a period of 5 s.

Study of image quality of mirror via solar flux distribution measurement using a high speed optical scanner

A method to study the solar flux distributions of the solar images reflected by mirrors with different dielectric thicknesses is proposed in this paper. An optical scanner, also known as a flux mapping system, capable of acquiring the flux distribution pattern of a light source in a two-dimensional flat surface, has been designed and constructed. The optical scanner can measure the profile of flux distribution at reasonably high resolution with fewer photo-sensors with a fast scanning speed of several seconds. The real time measurement results of solar images projected by mirrors with dielectric thicknesses, i.e., 3 mm, 4 mm, 5 mm and 6 mm, have been performed to analyze their surface qualities.

Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non...

Flux Distribution Analysis of Non-Imaging Planar Concentrator Considering Effects of Circumsolar Radiation and Mirror Slope Error

Systematic computational study on effects of circumsolar radiation and mirror slope error to flux distribution of non-imaging planar concentrator incorporated in concentrator photovoltaic system was performed using numerical simulation method

Optimizing performance of dense-array concentrator photovoltaic system

To optimize performance of dense array concentrator photovoltaic (CPV) system, we have acquired real time flux distribution pattern using novel optical scanner and then fed the data to computational modeling algorithm for the sake of designing optimized configuration of dense-array layout. As a case study, a prototype of non-imaging planar concentrator (NIPC) capable of producing reasonable uniform solar irradiance has been constructed to verify our new methodology in optimizing performance of CPV system. Current mismatch effect in dense array solar cells is crucial drawback that greatly affects electrical performance of CPV systems due to non-uniformity of solar irradiance. It always happens to any solar concentrator including NIPC prototype in which the non-uniformity is usually attributed to solar disc effect, slope error of reflective surface, structure misalignment, sun-tracking error etc. Improper handling of current mismatch problem can reduce maximum output power of the array considerably if a current-voltage (I-V) curve has many mismatch steps which will subsequently lead to low fill factor (FF) as well as conversion efficiency. Our computational modeling method is also validated via the work of field testing on the optimized configuration of dense-array solar cells with the NIPC prototype. The measured results are found to be in close agreement with the simulated results using the computational modeling in maximum output power.