Numerical Simulations of an Al2O3-Water Nanofluid-Based Linear Fresnel Solar Collector

Abstract

This study aims to numerically investigate the performance of Al2O3-water nanofluid as a heat transfer fluid (HTF) in a linear Fresnel solar receiver. Although a reasonable number of studies have investigated the thermal behaviors of different nanofluids as HTF in solar collectors, the focus has so far been on the parabolic trough collectors, with little or no research efforts available for the linear Fresnel collectors. ANSYS-fluent software was utilized for the simulation in this study, which converted the governing equations to algebraic forms based on the control-volume approach. The Nusselt number and wall temperature were used to characterize the thermal performance of the nanofluid, while the friction factor and eddy viscosity were considered to determine the flow features. The correlation equation proposed by Gnielinski was used to determine the Nusselt number, while the flow features were computed using the Darcy-Weisbach equation. Additionally, the thermal performance of the nanofluid was compared directly with that of pure water. Results showed that the nanofluid improved the thermal performance by about 6-19 % across the solar receiver length. Also, the Nusselt number increases non-uniformly across the length, with a significant rise towards the trailing edge of the nanofluid flow. Conversely, the pressure drop also increases with an increase in the solar receiver length, albeit uniformly. Designers should always factor into the design process to determine the optimum solar collector length when a nanofluid is considered as the HTF; to maximize heat transfer and minimize pressure drop and its attendant economic consequences.

Keywords

• Numerical simulation
• Nanofluid
• Al2O3 nanoparticles
• Heat transfer analysis
• Linear Fresnel collectors
• Solar receivers

References

1. [1] Abed, N.; Afgan, I.; Cioncolini, A.; Iacovides, H.; Nasser, A. Effect of various multiple strip inserts and nanofluids on the thermal-hydraulic performances of parabolic trough collectors. Appl. Therm. Eng. 2022, 201, 117798, doi:10.1016/j.applthermaleng.2021.117798.
2. [2] Ajbar, W.; Parrales, A.; Huicochea, A.; Hernández, J.A. Different ways to improve parabolic trough solar collectors’ performance over the last four decades and their applications: A comprehensive review. Renew. Sustain. Energy Rev.2022, 156, doi:10.1016/j.rser.2021.111947.
3. [3] Al-Oran, O.; Lezsovits, F. Recent experimental enhancement techniques applied in the receiver part of a parabolic trough collector – A review. Int. Rev. Appl. Sci. Eng. 2020, 11, 209–219, doi:10.1556/1848.2020.00055.
4. [4] Ashour, A.F.; El-Awady, A.T.; Tawfik, M.A. Numerical investigation on the thermal performance of a flat plate solar collector using ZnO & CuO water nanofluids under Egyptian weathering conditions. Energy 2022, 240, doi:10.1016/j.energy.2021.122743.
5. [5] Babapour, M.; Akbarzadeh, S.; Valipour, M.S. An experimental investigation on the simultaneous effects of a helically corrugated receiver and nanofluids in a parabolic trough collector. J. Taiwan Inst. Chem. Eng. 2021, 128, 261–275, doi:10.1016/j.jtice.2021.07.031.
6. [6] Benabderrahmane, A.; Benazza, A.; Laouedj, S.; Solano, J.P. Numerical analysis of compound heat transfer enhancement by single and two-phase models in parabolic trough solar receiver. Mechanika 2017, 23, 55–61, doi:10.5755/j01.mech.23.1.14053.
7. [7] do Carmo Zidan, D.; Brasil Maia, C.; Reza Safaei, M. Performance evaluation of various nanofluids for parabolic trough collectors. Sustain. Energy Technol. Assessments 2022, 50, 101865, doi:10.1016/j.seta.2021.101865.
8. [8] Fahim, T.; Laouedj, S.; Abderrahmane, A.; Alotaibi, S.; Younis, O. Heat Transfer Enhancement in Parabolic through Solar Receiver : A Three-Dimensional Numerical Investigation. 2022, 1–19.

9. [9] Islam, M.K.; Hasanuzzaman, M.; Rahim, N.A.; Nahar, A. Effect of nanofluid properties and mass a -flow rate on heat transfer of o parabolic -trough concentrating solar system. J. Nav. Archit. Mar. Eng. 2019, 16, 33–44, doi:10.3329/jname.v16i1.30548.
10. [10] Kumaresan, G.; Sudhakar, P.; Santosh, R.; Velraj, R. Experimental and numerical studies of thermal performance enhancement in the receiver part of solar parabolic trough collectors. Renew. Sustain. an Energy Rev. 2017, 77, 1363–1374, doi:10.1016/j.rser.2017.01.171.
11. [11] Mahmoudi, A.; Fazli, M.; Morad, M.R.; Gholamalizadeh, E. Thermo-hydraulic performance enhancement of nanofluid-based linear solar receiver tubes with forward perforated ring steps and triangular cross-section; a numerical investigation. Appl. Therm. Eng. 2020, 169, 114909, doi: 10.1016/j.applthermaleng.2020.114909.
12. [12] Mwesigye, A.; Meyer, J.P. Optimal thermal and thermodynamic performance of a solar parabolic trough receiver with different nanofluids and at different concentration ratios. Appl. Energy 2017, 193, 393–413, doi:10.1016/j.apenergy.2017.02.064.
13. [13] Peng, H.; Guo, W.; Li, M. Thermal-hydraulic and thermodynamic performances of liquid metal based nanofluid in parabolic trough solar receiver tube. Energy 2020, 192, 116564, doi:10.1016/j.energy.2019.116564.
14. [14] Răboacă, M.S.; Badea, G.; Enache, A.; Filote, C.; Răsoi, G.; Rata, M.; Lavric, A.; Felseghi, R.-A. Concentrating Solar Power Technologies. Energies 2019, 12, 1048, doi:10.3390/en12061048.
15. [15] Sandeep, H.M.; Arunachala, U.C. Solar parabolic trough collectors: A review on heat transfer augmentation techniques. Renew. Sustain. Energy Rev. 2017, 69, 1218–1231, doi:10.1016/j.rser.2016.11.242.
16. [16] Souza, R.R.; Gonçalves, M.; Rodrigues, R.O.; Minas, G.; Miranda, J.M. Recent advances on the thermal properties and applications of nanofluids : From nanomedicine to renewable energies. 2022, 201, doi: 10.1016/j.applthermaleng.2021.117725.
17. [17] Subramani, J.; Sevvel, P.; Anbuselvam; Srinivasan, S.A. Influence of a CNT coating on the efficiency of a solar parabolic trough collector using AL2O3 nanofluids - A multiple regression approach. Mater. Today Proc. 2021, 45, 1857–1861, doi:10.1016/j.matpr.2020.09.047.
18. [18] Vahedi, B.; Golab, E.; Nasiri Sadr, A.; Vafai, K. Thermal, thermodynamic and exergoeconomic investigation of a parabolic trough collector utilizing nanofluids. Appl. Therm. Eng. 2022, 206, 118117, doi: 10.1016/j.applthermaleng.2022.118117.
19. [19] Wole-osho, I.; Okonkwo, E.C.; Abbasoglu, S.; Kavaz, D. Nanofluids in Solar Thermal Collectors: Review and Limitations; Springer US, 2020; Vol. 41; ISBN 0123456789.
20. [20] Ying, Z.; He, B.; Su, L.; Kuang, Y.; He, D.; Lin, C. Convective heat transfer of molten salt-based nanofluid in a receiver tube with non-uniform heat flux. Appl. Therm. Eng. 2020, 181, doi: 10.1016/j.applthermaleng.2020.115922.