THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

online first only

Enhancing solar collector performance: An experimental study on zigzag rectangular angled strips and nanofluid integration

ABSTRACT
Solar thermal collectors have become an increasingly popular technology for harnessing renewable energy and have gained significant attention as a sustainable solution to meet the growing global energy demands. These systems efficiently convert solar radiation into thermal energy, making them a viable option for a variety of applications across the residential, commercial, and industrial sectors. The use of nanofluids as the working fluid in solar thermal collectors has been extensively investigated as the incorporation of nanoparticles has been demonstrated to enhance the thermal properties of these systems ultimately leading to improvements in their overall efficiency. This experimental study investigates the performance of a conjugate flat-plate solar collector with the inclusion of zigzag rectangular shaped angled strips inside the absorber tube. The study also explores the use of various nanofluids such as MgO/DIW, ZnO/DIW, and Al2O3/DIW at a 1.0% volume concentration as the working fluid to determine their potential for enhancing the thermal efficiency of the solar collector. The experiments were conducted with 450 angled strips at three different pitch ratios (Y = 2.0, 3.0, and 4.0) under identical working conditions. The performance of the rectangular shaped zigzag strip enhanced collectors was systematically compared to that of plain conjugate flat-plate solar collector collectors. For a pitch ratio of 2.0, MgO/DIW, ZnO/DIW, and Al2O3/DIW improve heat transfer by 30%, 28%, and 22% at higher Reynolds numbers compared to DIW. The MgO/DIW consistently provides the highest heat transfer enhancement across all configurations and pitch ratios. The Nusselt number increases by 45%, 42%, and 40% for MgO/DIW, ZnO/DIW and Al2O3/DIW at a pitch ratio of 2.0 showed a significant enhancement in heat transfer due to nanoparticle effects and zigzag rectangular angled strip induced turbulence. The thermal efficiency reaches around 85% for MgO/DIW nanofluids compared to DIW at a lower pitch ratio of 2.0. The friction factor increases by 15% for ZnO/DIW at lower Reynolds numbers compared to DIW. The Pumping power increased by 10% for ZnO/DIW in zigzag rectangular angled strip tubes compared to plain tubes. These findings revealed that utilizing high thermal conductivity nanofluids and zigzag rectangular strip geometries with optimized pitch ratios can enhance the performance of heat transfer systems especially in applications such as solar energy collectors and heat exchangers.
KEYWORDS
PAPER SUBMITTED: 2024-07-09
PAPER REVISED: 2024-10-28
PAPER ACCEPTED: 2024-12-04
PUBLISHED ONLINE: 2025-01-09
DOI REFERENCE: https://doi.org/10.2298/TSCI240709287S
REFERENCES
  1. Lee et al. Sun Tracking Systems: A Review. Sensors, no.9 (2009):3875-3890
  2. Shin et al. Investigation of Nanofluids for Solar Thermal Storage Applications. Proceedings of the ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences, no.19-23 (2009): 819-822
  3. Javadipour et al. Characterization of Al12Mg17 Nanofluid by Dynamic Light Scattering and Beam Displacement Methods. Cornell University, (2023): 2306. 13766
  4. Yang et al .Thermal Stability and Performance Testing of Oil-based CuO Nanofluids for Solar Thermal Applications. Multidisciplinary Digital Publishing Institute, no. 13(4) (2020):876-876
  5. Hai et al. Energy and cost management of different mixing ratios and morphologies on mono and hybrid nanofluids in collector technologies. Engineering Applications of Computational Fluid Mechanics Taylor & Francis, no 17(1) (2023): 2164620
  6. Hawwash et al. Thermal Analysis of Flat Plate Solar Collector Using Different Nanofluids and Nanoparticles Percentages . Institute of Electrical and Electronics Engineers, No.9 (2021): 52053-52066
  7. Mostafizur et al.Thermodynamic Analysis of a Flat Plate Solar Collector with Different Hybrid Nanofluids as Working Medium-A Thermal Modelling Approach. Multidisciplinary Digital Publishing Institute. no. 8.(2023): 1320-1320
  8. Sheikholeslami et al . Recent progress on flat plate solar collectors and photovoltaic systems in the presence of nanofluid: A review. Elsevier BV, no. 293 (2021): 126119-126119
  9. Singh et al. Energy and Exergy Analysis of a Rectangular-Shaped Mini-Channel Flat-Plate Solar Collector Using Tio2-Water and Cu-Water Nanofluids. Science and Engineering Research Support Society, no. 2 (2023):806-826
  10. Saffarian et al. Heat transfer enhancement in a flat plate solar collector with different flow path shapes using nanofluid . Elsevier BV, no.146 (2019): 2316-2329
  11. Peng et al. Investigation of energy performance in a U-shaped evacuated solar tube collector using oxide added nanoparticles through the emitter, absorber and transmittal environments via discrete ordinates radiation method. Springer Science Business Media, no. 4 (2019): 2623-2631
  12. Arora et al. Energy and Exergy Analysis of Marquise Shaped Channel Flat Plate Solar Collector Using Al2O3-Water Nanofluid and Water. Journals of solar Engineering , no. 4 (2019): 041008
  13. Sheikholeslami et al. Analyzing entropy and thermal behavior of nanomaterial through solar collector involving new tapes . Elsevier BV, no.123 (2021) :105190
  14. Panda et al. Nanofluid Based Pipe Flow Analysis in Absorber Pipe of Flat Plate Solar Collector: Effects of Inclination and Porosity. American Scientific Publishers. no. 2 (2023) :458-464
  15. Bezaatpour et al. Design and evaluation of flat plate solar collector equipped with nanofluid, rotary tube, and magnetic field inducer in a cold region. Elsevier BV, no. 170 (2021): 574-586
  16. Yan et al. Effect of U-shaped absorber tube on thermal-hydraulic performance and efficiency of two-fluid parabolic solar collector containing two-phase hybrid non-Newtonian nanofluids. Elsevier BV, no 185 (2020) :105832
  17. Suthahar et al .Experimental investigation on solar flat plate collector using alumina nanofluid with tube inserts. Maney Publishing, no. 3 (2020) 179-189
  18. Hussein et al. Thermal performance enhancement of a flat plate solar collector using hybrid nanofluid. Elsevier BV, no. 204 (2020) 208-222
  19. Peng et al. Investigation of energy performance in a U-shaped evacuated solar tube collector using oxide added nanoparticles through the emitter, absorber and transmittal environments via discrete ordinates radiation method. J Therm Anal Calorim, no.139 (2019) 2623-2631
  20. Eltaweel et al. Indirect thermosiphon flat‐plate solar collector performance based on twisted tube design heat exchanger filled with nanofluid. International Journal of Energy Research, no.44 (2020) 4269 - 4278
  21. Allouhi et al. Heat pipe flat plate solar collectors operating with nanofluids. Solar Energy Materials and Solar Cells, no. 219.(2021) :110798
  22. Munuswamy et al. Experimental investigation on lowering the environmental hazards and improving the performance patterns of solar flat plate collectors by employing the internal longitudinal fins and nano additives. Environmental Science and Pollution Research, no. 27.(2020) 45390-45404
  23. Holman et al. Experimental Methods for Engineers. seventh ed. McGraw-Hill, New York, (2001)
  24. Shajahan et al .Heat transfer investigations of in-line conical strip inserts using MWCNT/water nanofluid under laminar flow condition. International Journal of Thermal Sciences, no. 183(2023) :107844
  25. Mwesigye et al. Heat Transfer and Thermodynamic Performance of a Parabolic Trough Receiver with Centrally Placed Perforated Plate Inserts. Appl. Energy ,no.136 (2014) :989-1003
  26. Chaurasia et al. Numerical and Experimental Thermal Performance with Entropy Generation Analysis on Tube with Helical Screw Tape Inserts at Number of Strips in Turbulent Flow. Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci. no. 235 (2021):1057-1070
  27. Chakraborty et al. Impact of Helical Coil Insert in the Absorber Tube of Parabolic Trough Collector. Smart Innov. Syst. Technol, no 206 (2021): 177-187
  28. Chakraborty et al. Heat Transfer Enhancement Analysis of Parabolic Trough Collector with Straight and Helical Absorber Tube. Therm. Sci. Eng. Prog, no.20 (2020) :100718
  29. Kalogirou et al. Solar Energy Engineering: Processes and Systems. 2nd ed.; Elsevier Inc.: Amsterdam, The Netherlands, (2009)
  30. Mebarek-Oudina et al . Entropy and convection effect on magnetized hybrid nano-liquid flow inside a trapezoidal cavity with zigzagged wall. International Communications in Heat and Mass Transfer, no.125 (2021): 105279
  31. Bisheh et al. Impact of hybrid nanofluids (Ag‐TiO2/H2O) on improving the performance of a heat exchanger with turbulent induction elements. Engineering Reports, no. 4 (2022): 12502
  32. Louis et al. Application of Nanofluids in Improving the Performance of Double-Pipe Heat Exchangers-A Critical Review. Materials, 15 (2022): 6879
  33. Abdullah et al. Impact of coil pitch on heat transfer enhancement of a turbulent flow of α-Al2O3/DW nanofluid through helical coils. Thermal Science, no. 6 (2023):5005-5014
  34. Kwak et al. Numerical investigation of nanoparticle deposition location and pattern on a sharp-bent tube wall. International Journal of Heat and Mass Transfer, no.164 (2021): 120534
  35. Huang et al. Energy dissipation mechanism of a centrifugal pump with entropy generation theory. AIP Advances, no.11 (2021):045208