Performance Investigation of Solar Parabolic Trough Collector Alternatives.

Parabolic trough collectors (PTCs) are the most advanced and widely used technology in solar concentrating systems. However, their high-cost and high-technology requirements for parabolic mirror manufacturing constituted real shortcomings for their implementation in low-income countries, which urged the need for finding replacements for them. This study assessed the performance of two small-scale solar thermal production units, namely a semi-parabolic linear Fresnel reflector (SPLFR) and a PTC with stainless-steel (PTC-SS) sheet reflector as alternatives for PTCs. The impact of tracking, surface, and displacement errors and reflectivity on the flux distribution and uniformity index were investigated for both designs. Firstly, it was observed that PTC-SS presented a better intercept factor compared to SPLFR for 1° tracking error. Secondly, a displacement error of 6.2 mm seemed to have a significant effect on the performance of SPLFR and a slight effect on that of PTC-SS reflector. Thirdly, the optical efficiency for SPLFR reached 77.8% of the available solar flux while that of PTC-SS reflector reached 71.3%. Fourthly, an experimental test confirmed that the overall efficiency of SPLFR is better than that of PTC-SS. Consequently, SPLFR would be a better potential alternative to conventional PTC for low-income countries because of its rather acceptable performance, easier manufacture, low cost, use of recyclable mirrors as well as its more uniform flux shape in the receiver circumference. [ABSTRACT FROM AUTHOR]