Optimizing Heat Transfer Performance of Solar Air Heaters: Influence of Hexagonal Inline and Staggered Ribs with Different Blockage Ratios in Trapezoidal Ducts

International Journal of Mechanical Engineering

© 2025 by SSRG - IJME Journal

Volume 12 Issue 9

Year of Publication : 2025

Authors : Nilesh M. Shinde, Himanshu Borade

10.14445/23488360/IJME-V12I9P112

How to Cite?

Nilesh M. Shinde, Himanshu Borade, "Optimizing Heat Transfer Performance of Solar Air Heaters: Influence of Hexagonal Inline and Staggered Ribs with Different Blockage Ratios in Trapezoidal Ducts," SSRG International Journal of Mechanical Engineering, vol. 12,  no. 9, pp. 115-129, 2025. Crossref, https://doi.org/10.14445/23488360/IJME-V12I9P112

Abstract:

Demand for energy supply is growing daily; dependency on fossil fuels is unreliable as the fossil fuels become depleted. Sustainable energy is the leading energy source for meeting global demands. Solar air heaters are one of the uses of sustainable energy. This experimental study examined the THP of a solar air heater that uses a hexagonal rib on the plate that absorbs. This study examines the effects of rib height ratio (e/Dh = 0.1109, 0.1479, and 0.1849), rib pitch (P = 60 mm, 80 mm, and 100 mm), and attack angle (α = 90° and 120°) on the transmission of heat enhancement within a trapezoidal duct for the Re of 5000-30000. To enhance the plate area and interplay of heat, trapezoidal ducts were selected. The experimental work shows that the Reynolds number leads the Nusselt number to rise for different blockage ratios. For 120° staggered ribs, with the ultimate blockage ratio, e/Dh=0.1849 performs better than all other ribs. The maximum heat transfer is higher by as much as 56% over a smooth duct, but there is more friction. The 120° rib orientation, particularly in staggered configurations, outperformed the 90° orientation. With the lowest Reynolds number, the 120° staggered rib exhibits a maximum thermal performance of 1.92, which is 29.7 percent better than the similar 90° orientation's 1.48. More thermal performance with controllable pressure losses is possible with a greater blockage ratio and a high angle of attack. In general, the absorber with hexagonal ribs improves thermal efficiency, which is a great and affordable way to make solar air heaters work better.

Keywords:

Hexagonal ribs, Blockage ratio, Heat transfer enhancement, Convective heat transfer, Artificial Roughness.

References:

[1] Abdulmohsen O. Alsaiari et al., “Heat Transmission and Air Flow Friction in a Solar Air Heater with a Ribbed Absorber Plate: A Computational Study,” Case Studies in Thermal Engineering, vol. 40, pp. 1-9, 2022.
[CrossRef] [Google Scholar] [Publisher Link]
[2] Harish K. Ghritlahre, and Radha K. Prasad, “Prediction of Exergetic Efficiency of Arc Shaped Wire Roughened Solar Air Heater Using ANN Model,” International Journal of Heat and Technology, vol. 36, no. 3, pp. 1107-1115, 2018.
[CrossRef] [Google Scholar] [Publisher Link]
[3] Rahul Kumar et al., “Experimental Assessment and Modeling of Solar Air Heater with V Shape Roughness on Absorber Plate,” Case Studies in Thermal Engineering, vol. 43, pp. 1-9, 2023.
[CrossRef] [Google Scholar] [Publisher Link]
[4] J. Nikuradse, “Laws of Flow in Rough Pipes,” National Advisory Committee for Aeronautics, Report, pp. 1-63, 1950.
[Google Scholar] [Publisher Link]
[5] Yogesh Agrawal et al., “Investigation of Thermal Performance of a Ribbed Solar Air Heater for Sustainable Built Environment,” Sustainable Energy Technologies and Assessments, vol. 57, 2023.
[CrossRef] [Google Scholar] [Publisher Link]
[6] Foued Chabane et al., “Experimental Study of a Solar Air Heater by Adding an Arrangement of Transverse Rectangular Baffles Perpendicular to the Air Stream,” International Journal of Green Energy, vol. 16, no. 14, pp. 1264-1277, 2019.
[CrossRef] [Google Scholar] [Publisher Link]
[7] Kottayat Nidhul et al., “Thermo-Hydraulic and Exergetic Performance of a Cost-Effective Solar Air Heater: CFD and Experimental Study,” Renewable Energy, vol. 184, pp. 627-641, 2022.
[CrossRef] [Google Scholar] [Publisher Link]
[8] Hani Abulkhair et al., “Heat Transfer and Air Flow Friction in Solar Air Heaters: A Comprehensive Computational and Experimental Investigation with Wire-Roughened Absorber Plate,” Case Studies in Thermal Engineering, vol. 48, pp. 1-18, 2023. [CrossRef] [Google Scholar] [Publisher Link]
[9] R. Kamali, and A.R. Binesh, “The Importance of Rib Shape Effects on the Local Heat Transfer and Flow Friction Characteristics of Square Ducts with Ribbed Internal Surfaces,” International Communications in Heat and Mass Transfer, vol. 35, no. 8, pp. 1032-1040, 2008.
[CrossRef] [Google Scholar] [Publisher Link]
[10] Wei Peng et al., “Experimental and Numerical Investigation of Convection Heat Transfer in Channels with Different Types of Ribs,” Applied Thermal Engineering, vol. 31, no. 14-15, pp. 2702-2708, 2011.
[CrossRef] [Google Scholar] [Publisher Link]
[11] B. Varun Kumar et al., “Enhancement of Heat Transfer in SAH with Polygonal and Trapezoidal Shape of the Rib Using CFD,” Energy, vol. 234, 2021.
[CrossRef] [Google Scholar] [Publisher Link]
[12] Karmveer et al., “An Experimental Study of Thermohydraulic Performance of Solar Air Heater Having Multiple Open Trapezoidal Rib Roughnesses,” Experimental Heat Transfer, vol. 37, no. 3, pp. 313-333, 2024.
[CrossRef] [Google Scholar] [Publisher Link]
[13] Anil Singh Yadav, and J.L. Bhagoria, “A CFD Based Thermo-Hydraulic Performance Analysis of an Artificially Roughened Solar Air Heater Having Equilateral Triangular Sectioned Rib Roughness on the Absorber Plate,” International Journal of Heat and Mass Transfer, vol. 70, pp. 1016-1039, 2014.
[CrossRef] [Google Scholar] [Publisher Link]
[14] Yadaba Mahanand, and Jnana Ranjan Senapati, “Thermal Enhancement Study of a Transverse Inverted-T Shaped Ribbed Solar Air Heater,” International Communications in Heat and Mass Transfer, vol. 119, 2020.
[CrossRef] [Google Scholar] [Publisher Link]
[15] Yash M. Patel, Sanjay V. Jain, and Vikas J. Lakhera, “Thermo-Hydraulic Performance Analysis of a Solar Air Heater Roughened with Discrete Reverse NACA Profile Ribs,” International Journal of Thermal Sciences, vol. 167, 2021.
[CrossRef] [Google Scholar] [Publisher Link]
[16] Yadaba Mahanand, and Jnana Ranjan Senapati, “Thermo-Fluid Analysis of a Pentagonal Ribbed Triangular Solar Air Heater Duct (TSAHD): A Three-Dimensional Numerical Investigation,” International Communications in Heat and Mass Transfer, vol. 137, 2022.
[CrossRef] [Google Scholar] [Publisher Link]
[17] Nitesh Dutt et al., “Thermo-Hydraulic Performance of Solar Air Heater having Discrete D-shaped Ribs as Artificial Roughness,” Environmental Science and Pollution Research, pp. 1-22, 2023.
[CrossRef] [Google Scholar] [Publisher Link]
[18] Kottayat Nidhul et al., “Enhanced Thermo-Hydraulic Performance in a V-Ribbed Triangular Duct Solar Air Heater: CFD and Exergy Analysis,” Energy, vol. 200, 2020.
[CrossRef] [Google Scholar] [Publisher Link]
[19] V.S. Hans, R.P. Saini, and J.S. Saini, “Heat Transfer and Friction Factor Correlations for a Solar Air Heater Duct Roughened Artificially with Multiple V-Ribs,” Solar Energy, vol. 84, no. 6, pp. 898-911, 2010.
[CrossRef] [Google Scholar] [Publisher Link]
[20] Dongxu Jin et al., “Numerical Investigation of Heat Transfer Enhancement in a Solar Air Heater Roughened by Multiple V-Shaped Ribs,” Renewable Energy, vol. 134, pp. 78-88, 2019.
[CrossRef] [Google Scholar] [Publisher Link]
[21] Adisu Bekele, Manish Mishra, and Sushanta Dutta, “Performance Characteristics of Solar Air Heater with Surface Mounted Obstacles,” Energy Conversion and Management, vol. 85, pp. 603-611, 2014.
[CrossRef] [Google Scholar] [Publisher Link]
[22] Madhukeshwara Nanjundappa, “Optimum Thermo-Hydraulic Performance of Solar Air Heater Provided with Cubical Roughness on the Absorber Surface,” Experimental Heat Transfer, vol. 33, no. 4, pp. 374-387, 2020.
[CrossRef] [Google Scholar] [Publisher Link]
[23] A. Leander Antony et al., “Influence of Stepped Cylindrical Turbulence Generators on the Thermal Enhancement Factor of a Flat Plate Solar Air Heater,” Solar Energy, vol. 198, pp. 295-310, 2020.
[CrossRef] [Google Scholar] [Publisher Link]
[24] H.S. Arunkumar, Shiva Kumar, and K. Vasudeva Karanth, “Analysis of a Solar Air Heater for Augmented Thermohydraulic Performance Using Helicoidal Spring Shaped Fins-A Numerical Study,” Renewable Energy, vol. 160, pp. 297-311, 2020.
[CrossRef] [Google Scholar] [Publisher Link]
[25] Parag Jyoti Bezbaruah, Rajat Subhra Das, and Bikash Kumar Sarkar, “Experimental and Numerical Analysis of Solar Air Heater Accoutered with Modified Conical Vortex Generators in a Staggered Fashion,” Renewable Energy, vol. 180, pp. 109-131, 2021.
[CrossRef] [Google Scholar] [Publisher Link]
[26] A. Saravanan et al., “Thermo-Hydraulic Performance of a Solar Air Heater with Staggered C-Shape Finned Absorber Plate,” International Journal of Thermal Sciences, vol. 168, 2021.
[CrossRef] [Google Scholar] [Publisher Link]
[27] Sohan Lal Sharma et al., “CFD Analysis of Artificially Roughened Solar Air Heater: A Comparative Study of C-Shape, Reverse C-Shape, and Reverse R-Shape Roughness Element,” International Journal of Ambient Energy, vol. 45, no. 1, 2024.
[CrossRef] [Google Scholar] [Publisher Link]
[28] Leila N. Azadani, and Nadiya Gharouni, “Multi Objective Optimization of Cylindrical Shape Roughness Parameters in a Solar Air Heater,” Renewable Energy, vol. 179, pp. 1156-1168, 2021.
[CrossRef] [Google Scholar] [Publisher Link]
[29] Hassan A.H. Alzahrani et al., “Enhancing Solar Air Heater Efficiency with 3D Cylinder Shaped Roughness Elements,” Case Studies in Thermal Engineering, vol. 51, pp. 1-17, 2023.
[CrossRef] [Google Scholar] [Publisher Link]
[30] Abdulmohsen O. Alsaiari et al., “Heat Transfer Augmentation in a Solar Air Heater with Conical Roughness Elements on the Absorber,” Case Studies in Thermal Engineering, vol. 36, pp. 1-14, 2022.
[CrossRef] [Google Scholar] [Publisher Link]
[31] Vikash Kumar, and Ramesh Murmu, “Performance Based Investigation of Inclined Spherical Ball Roughened Solar Air Heater,” Applied Thermal Engineering, vol. 224, 2023.
[CrossRef] [Google Scholar] [Publisher Link]