Simulation and Experimental Study on the Optical Performance of a Fixed-Focus Fresnel Lens Solar Concentrator Using Polar-Axis Tracking

Abstract

Most sun-tracking systems of solar concentrators are expensive, sensitive to operational costs, and complicated in optical design in which the receiver must be free to rotate about the axis. To overcome the aforementioned problems, this study presents a fixed-focus Fresnel lens solar concentrator (FFFSC) using polar-axis tracking which allows the Fresnel lens to concentrate sunlight to a fixed small heat-receiving area and the receiver remained fixed in location and rotation. Experimental research has been conducted to obtain the optical characteristics of the FFFSC for different solar times, tracking errors, and periodical adjustment errors. It has been found that maximum values of the relative optical efficiency loss (η re-opt,loss) and minimum value of the optical efficiency (η opt) of the FFFSC for different solar times are 1.87% and 71.61%, respectively. The mean value and maximum value of the local concentration ratio of the solar flux on the receiver are more than 86.64 and 1319.43, respectively. When the tracking error and periodical adjustment error are within 1 • , the η opt of the FFFSC can reach 70.38% and 68.94%, respectively. The optical characteristics of FFFSC is also verified numerically. Especially, according to the total year simulation of the FFFSC's optical characteristics, maximum value of η re-opt,loss is 0.116%, which means the proposed the FFFSC can achieve fixed-focus.

Liquid and Photoliquefiable Azobenzene Derivatives for Solvent-free Molecular Solar Thermal Fuels

“…Seeking solutions for solar storage and conversion is one of the most promising means to improve solar utilization and reduce carbon emissions from fossil fuels. − In recent years, more attention has been paid to the photochemical storage and conversion of solar energy through molecular solar thermal fuels (MSTFs), a clean, emission-free closed cycling system. − The so-called MSTFs are based on the photoswitchable molecules that absorb photons in a steady state to generate high-energy, metastable isomers and then release the stored energy as heat during back conversion upon external triggering such as heat, light, or catalysis.…”

Investigation of steam generation performance on conical cavity receiver by different geometric concentration ratios for fresnel lens solar concentrator

“…The paper [15] performed a simulation of the performance of a PMMA Fresnel lens shown in the form of optical efficiency, which could reach between 68.94 % to 70.38 %. Furthermore, the same author [16] developed the use of Fresnel lenses for solar cookers.…”

Optical Performance Comparison of Different Shapes of Cavity Receiver in the Fixed Line-Focus Solar Concentrating System

“…According to the analysis, the hemispherical cavity receiver led to maximum thermal efficiency with the nanofluid used. Wang et al [20,21] investigated the effects of receiver parameters on the optical performance of a Fresnel lens solar system. The analysis shows that average optical efficiencies using cavity receiver with the bottom reflective cone of spherical, cylindrical, and conical are 72.23%, 68.37%, and 76.40%, respectively.…”