South African Journal of Science
On-line version ISSN 1996-7489
FERRER, P.. Enhanced efficiency of a parabolic solar trough system through use of a secondary radiation concentrator. S. Afr. j. sci. [online]. 2008, vol.104, n.9-10, pp. 383-388. ISSN 1996-7489.
Solar electric energy is not yet economically competitive with fossil fuels. Apart from large capital outlay, solar systems suffer from low efficiency of converting solar energy to electric power. In this paper, a receiver for a solar trough was investigated in which the dominant radiation losses were suppressed by reducing the radiation area. The concentration ratio of the primary concentrator (a parabolic mirror) was enhanced by use of a simple secondary concentrator (an optical funnel), which minimized the width of the focal line. The resultant radiation losses were significantly reduced (by 22%). The novel aspect in this work was the design and modelling of a solar radiation receiver with secondary concentrator and black-body chamber. An initial model of this receiver showed an improvement of overall efficiency of about 1% for solar to electric power generation as compared to conventional receivers. Application of a receiver built on this model could reduce heat losses and costs of a solar trough system.