Experimental Characterization and Statistical Analysis of Water‐Based Gold Nanofluids for Solar Applications: Optical Properties and Photothermal Conversion Efficiency

Abstract

Optimizing optical and photothermal properties of the solar nanofluids (NFs) to be used in direct absorption solar collectors is a key issue to maximize efficiencies in these collector types. This work both experimentally and statistically analyzes the influence of the size (5 and 20 nm) and concentration (5.1, 28.2, and 51.3 ppm) of gold nanoparticles (NPs) on several important variables for collector performance: NF stability, extinction coefficient, photothermal efficiency, etc. The research work shows that the addition of small amounts of gold NPs, whose surface plasmon resonance has wavelengths close to 520 nm, greatly improves the light absorption capacity of the base fluid (water). The statistical analysis confirms the influence of NP size and concentration on photothermal conversion efficiency (PTE), which lead to an increase of up to 121% for the smallest‐sized NF with the highest concentration.

Noble Nanofluids and Their Hybrids for Heat Transfer Enrichment: A Review and Future Prospects Coverage

“…Nonetheless, the influence of the size of the gold nanoparticles on the cube-shaped collector was not so evident as it happens in the flat-shaped collector. Besides, the authors Burgos et al [24] evaluated the impact of the concentration and dimensions of the gold nanoparticles dispersed in water on the parameters of a direct absorption solar collector, such as the stability of the nanofluids, extinction coefficient, and photothermal efficiency. The sizes of the nanoparticles were of 5 nm and 20 nm and their concentrations were of around 5 ppm, 28 ppm, and 51 ppm.…”

Modeling of the synergistic anti-reflection effect in gradient refractive index films integrated with subwavelength structures for photothermal conversion

“…Li et al 9 proposed a heterostructure of Bi 2 Te 3 /Cu and Fu et al 10 prepared hierarchical porous metallic glasses with microporous surfaces for enhanced solar energy absorption and heat management, thereby achieving efficient solar-thermal conversion and heat utilization. Research by Burgos et al 11 demonstrated that the photothermal conversion efficiency of solar collectors can be significantly improved by adjusting the size and concentration of gold nanoparticles introduced into solar nanofluids, resulting in a maximum increase of 121%. From the material perspective, further improvement of photothermal conversion efficiency by exploiting new composite materials or altering material components and structures is challenging, impeding further significant advancements in photothermal conversion efficiency.…”

Investigation on stable TiN plasmonic nanofluids for applications in direct absorption solar collectors

“…In recent years, the nanofluids with different types of nanoparticles, such as carbon materials, 9,10 semiconductors, 11,12 and noble metal nanoparticles, 13–17 have been investigated and discussed extensively in DASCs. Among them, the noble metal nanoparticles could enhance the light capture ability of the HTF due to its localized surface plasmon resonance (LSPR) in specific wavelength range 18 .…”