Enhancing thermal efficiency of parabolic trough collectors using SiO₂ nanofluids: a comparative study of particle size impact on solar energy harvesting

ABSTRACT

Solar energy technologies, particularly Parabolic Trough Solar Collectors (PTSCs), are crucial for efficient and scalable thermal applications in Concentrated Solar Power (CSP) plants. This study investigates the thermal efficiency of PTSCs utilizing silicon dioxide (SiO₂) nanofluids with varying particle sizes (20 nm, 50 nm, and 100 nm) compared to deionized (DI) water as the heat transfer fluid (HTF). The objective is to enhance PTSC performance by improving the HTF’s thermal properties by adding SiO2 nanoparticles. SiO₂ nanofluids were synthesized using the sol-gel method and characterized for thermal conductivity, viscosity, and specific heat capacity. _The novelty of this study lies in the comprehensive analysis of the effects of nanoparticle size on PTSC efficiency, which offers practical insights for optimizing solar thermal systems. Experimental setups measured PTSC thermal efficiency under varying solar irradiation and ambient temperature conditions. The results showed a significant improvement in thermal efficiency when using SiO₂ nanofluids, with the 20 nm nanoparticles exhibiting the highest enhancement of approximately 26% over DI water. The 50 nm and 100 nm nanoparticles showed 21% and 17% improvements, respectively. The increased efficiency is attributed to smaller nanoparticles’ higher surface area-to-volume ratio, which enhances thermal conductivity and reduces boundary layer thickness. Additionally, thermal conductivity increases with temperature and decreases with nanoparticle size, while specific heat capacity decreases with temperature and nanoparticle size. SiO₂ nanofluids, particularly those with smaller nanoparticles, significantly enhance the thermal performance of PTSCs. This study highlights the potential of nanofluids in solar thermal applications and provides a basis for further research on the long-term stability and economic viability of nanofluid-based HTFs.

KEYWORDS:

• Parabolic trough solar collectors
• nanofluids
• silicon dioxide nanoparticles
• solar energy harvesting
• energy efficiency

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2024.2378174

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Prabhakaran Sivaraman

Prabhakaran Sivaraman is with Knowledge Institute of Technology, Salem, India. His research focuses on advanced manufacturing processes, renewable energy systems, and materials engineering.

Visagavel Kolandaivel

Visagavel Kolandaivel is with the Knowledge Institute of Technology, Salem, India. His research interests include thermal engineering, energy optimization, and fluid dynamics.

Silambarasan Rajendran

Silambarasan Rajendran is affiliated with multiple institutions. His research areas encompass computational fluid dynamics, sustainable manufacturing, and nanomaterials for energy applications.

Ratchagaraja Dhairiyasamy

Ratchagaraja Dhairiyasamy is with the Shinawatra University. His research work includes robotics, automation, and the development of smart materials for mechanical systems.