Dear Rahmi,
The difference in performance between a CLFR and LFR system, or between different systems using the same linear Fresnel technology depends on the specific design characteristics of the system. It is not possible to provide a general value such as the 10% you suggest to describe the relative performance of two types of linear Fresnel system.
One reason for this is that linear Fresnel system designs involve a large number of parameters such as mirror spacing, mirror width, receiver height, receiver size, etc., and optimal values for these parameters are still being determined. For example, some preliminary NREL research suggests that the performance of a LFR system can be greatly improved by using non-uniform mirror spacing.
If you are comparing the performance of these system designs, we recommend that you 1) limit your comparison to specific cases rather than making generalized comparisons, and 2) ensure that the designs of both systems are fully optimized so that your comparison shows differences that can be attributed to the difference in technology and not to inefficient designs.
Ray-tracing is typically used to optimize the collector optimal performance for linear Fresnel and parabolic trough systems. NREL has developed a new analytical tool called FirstOPTIC that uses a new analytical approach to model collector optical performance. Its application for parabolic trough modeling is described in this NREL R&D Highlight (
PDF 292 KB
), and an article describing its use for linear Fresnel is forthcoming in the journal Solar Energy. For more information about FirstOPTIC for parabolic troughs: See
Zhu and Lewandowski in Solar Energy Engineering (2012)
, and
Binott, Zhu, et al. in Solar Energy (2013)
.
Best regards,
Paul.
