Critical Retrospect on Conventional and Luminescent Solar Concentration Devices

Abdul-Rahman

doi:10.3844/ajessp.2010.428.437

Abstract

Problem statement: Conventional solar concentrators are only sensitive for the beam radiation and they function poorly in overcast sky conditions. Even under a clear sky condition, trackers are always needed for conventional solar concentrators. Static concentrators always come with a poor concentration rate without a tracker and the light concentrated by normal Luminescent Solar Concentrators (LSC) could not be transported by optical fibers to a remote place since the light produced by LSCs is not a pointolite. Approach: Through a critical literature review and discussion, this article retrospects the merits and demerits of recent conventional solar concentrators and Luminescent Solar Concentrators (LSC). Results: Results summarized the limitations in current day lighting related solar concentration devices. As an approach for energy saving, daylight has a disadvantage of not being able to reach many areas of a building such as store rooms, basements and corridors and it also brings heat gain with the light. Light pipes were designed to transport daylight to unreached areas, but light pipes have their difficulties for wiring, so that optical fibers are considered as the best approach for the daylight transportation so far. However, the optical fiber needs a pointolite for the light transportation. Various solar concentrators that were designed using optical approaches such as using mirrors or lens for the solar energy concentration. Since they are only sensitive for the beam irradiation, they function poorly in the cloudy weather and the diffuse light conditions and even if they are under a clear sky condition, trackers are always needed. Luminescent Solar Concentrators (LSC) and some static solar concentrators were then designed as the diffuse light solution and the static solution, respectively. Static concentrators always come with a low concentration rate without a tracker and the light concentrated by normal LSCs could not be transported by optical fibers to a remote place since the light produced by an LSC is not a pointolite. Conclusion/Recommendations: New solar concentration systems need to be developed to mitigate the above-mentioned limitations. Future studies especially cross disciplinary researches on developing new solar concentrators in mitigating those limitations as discussed in this study are highly recommended.

Highlights

Besides the rapidly rising price of petroleum, anthropogenic activities, especially the burning of fossil fuels, have released pollutants into the atmosphere increasing global warming and depleting the ozone layer (Mills, 2002) To improve the situation there needs to be a decrease in energy of which fossil fuel is used
Static concentrators always come with a poor concentration rate without a tracker and the light concentrated by normal Luminescent Solar Concentrators (LSC) could not be transported by optical fibers to a remote place since the light produced by an LSC is not a pointolite (Kandilli et al, 2008)
The polymer sheets have a disadvantage in wiring, which brings difficulties in building integration. It is not energy-efficient to further concentrate the rectangular light produced by the LSC into a pointolite for the transportation through optical fibers to a remote place in a building

Summary

Introduction

Besides the rapidly rising price of petroleum, anthropogenic activities, especially the burning of fossil fuels, have released pollutants into the atmosphere increasing global warming and depleting the ozone layer (Mills, 2002) To improve the situation there needs to be a decrease in energy of which fossil fuel is used. Solar energy is made widely available for thermal applications, day lighting and direct production of electricity (Muhs, 2000; Reisfeld and Jorgensen, 1982; Rahoma, 2008). Artificial lighting is one of the major sources of electrical energy costs in office buildings, both directly through lighting energy consumption and indirectly by production of significant heat gain, which increases cooling loads. The recent interest in energy efficiency and sustainability has led to the implementation of design strategies in buildings aiming at the achievement of the optimal utilization of daylight with minimum energy consumption for lighting and cooling. Sun light as a clean energy source could contribute considerably to a solution of the energy problem if appropriate methods were developed to collect, concentrate, store and convert solar irradiation, Corresponding Author: Chen Wang, Centre for Construction Innovation and Project Management, Faculty of Built Environment, University of Malaya, Kuala Lumpur, Malaysia 428

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