A review of linear Fresnel primary optical design methodologies

Abstract

Linear Fresnel collector plants represent a promising line-focusing concentrating solar thermal technology that has not yet reached commercial maturity. This technology has many advantages, but its core disadvantage is the low optical performance of the primary collector field. The design of the primary is therefore of vital importance to the competitiveness of the technology. The large number of independent parameters in primary collector designs has led to many different optical design methodologies and optimisation studies. This review paper firstly details the different optical loss mechanisms and their relative importance to the performance of the primary. The different models used to quantify performance are then detailed. The subsequent sections categorise the collector primary design into three broad themes: designing for peak conditions (no blocking and shading for a vertical sun); design optimisation (from sensitivity studies to particle swarm and multi-objective optimisation studies); and novel linear Fresnel layouts. Novel layouts make use of additional degrees of freedom and non-imaging optics to create hybridised collector fields with enhanced optical efficiency. While this avenue shows much promise, the cost implications of the added complexity are typically not fully quantified.