A review on solar concentrators with multi-surface and multielement combinations

Solar concentrator always plays an important role in solar energy collection as it could enhance the energy density effectively. Various structures of solar concentrators have been researched in recent years, among which multi-surface (MS) and multi-element (ME) combinations are the two typical structures. MS concentrator is an improved structure for single surface concentrator. It is usually designed to increase the acceptance angle, enhance the light intercepting efficiency, homogenize the energy distribution, etc. ME concentrator is generally consist of two or more optical elements, in which MS concentrators are usually used as assistant optical components. ME concentrator always has larger tolerance on tracking error so that it is much easier to track the sun. It could be applied in high power concentration. The combination on optical elements of MS and ME solar concentrators was diagramed and theirs advantages and disadvantages were evaluated. Nowadays, solar applications are becoming more and more diverse and concomitantly, the researching methods are also improving. The computer-aided methods including numerical computation and optical simulation are the dominant method in nowadays, which makes it easier to analyze various structures of solar concentrators and their complex applications. Besides, solar applications are not limited in CT and CPV, but in many other fields such as solar daylighting, solar-pumped laser, solar cooling, solar desalination etc. It has been believed that more and more innovative designs on solar concentrator will be proposed in the future.