In this paper, the potential for improved thermal performance of a high concentration ratio parabolic trough solar energy system working with high thermal conductivity singlewalled carbon nanotubes (SWCNTs) and Therminol(r)VP-1 nanofluid is numerically investigated. In the numerical analysis, the practical heat flux profiles expected for parabolic trough receivers were obtained using Monte-Carlo ray tracing and coupled with a computational fluid dynamics tool using user defined functions to investigate the thermal performance of the parabolic trough solar energy system. A parabolic trough system with a concentration ratio of 113 was considered in this study and heat transfer fluid inlet temperatures between 400 K and 650 K were used. The volume fraction of SWCNTs in the base fluid was in the range 0% to 2.5% and the flow rates used were in the range 0.82 to 69.41 m3/h. Results show improvements in the convective heat transfer performance and receiver thermal efficiency as well as a considerable reduction of the receiver thermal losses with increasing volume fractions. The heat transfer performance increases up to 64% while the thermal efficiency increases by about 4.4%. Higher increments are observed at low flow rates and inlet temperatures. The receiver thermodynamic performance also increases significantly with the use of nanofluids. Entropy generation rates reduce by about 30% for the range of parameters considered.
|Original language||English (US)|
|Title of host publication||Heat Transfer and Thermal Engineering|
|Publisher||American Society of Mechanical Engineers (ASME)|
|State||Published - 2017|
|Event||ASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017 - Tampa, United States|
Duration: Nov 3 2017 → Nov 9 2017
|Name||ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)|
|Other||ASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017|
|Period||11/3/17 → 11/9/17|
Bibliographical noteFunding Information:
This work is based on the research supported in part by the National Research Foundation of South Africa (Grant No. 9927). The support received from the University of the Witwatersrand, Johannesburg and the University of Pretoria is also duly acknowledged and appreciated.
- Concentration Ratio
- Heat Transfer Performance Parabolic Trough Receiver
- Monte Carlo Ray Tracing
- Thermal Efficiency