Experimental Configuration and Operating Parameters of the Thermo-Fluid Energy Conversion System
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Abstract
The present experimental investigation describes an optimization of thermo-fluid energy conversion through the design of a compact sand-fluidized reactor with controlled air heating and interchangeable inlet geometries. The system includes a TEC1-12706 thermoelectric module for thermal conditioning, an air pump at variable speed, a transparent acrylic column filled with silica sand, and a small electrical generator for energy recovery. Effects of air velocity (0.5–1.5 m/s), temperature setpoint (30–90 °C), sand mass (100–300 g), and inlet geometry (Straight, Ring, V-shape) were examined systematically through a full factorial design with 81 operational conditions. The electrical power output, pressure drop, and thermal-to-electrical conversion efficiency were evaluated under steady-state operation. It has emerged from the results that inlet geometry has a decisive influence on hydrodynamic characteristics and energy performance. The Ring inlet always exhibited better flow uniformity with the most electrical power at (~3.5 W) at 1.5 m/s and 90 °C and a lower pressure drop (~450 Pa) than the Straight (~560 Pa) and V-shape (~660 Pa) configurations. Maximum thermal-to-electrical performance occurred in the range of 27–28% in the hot airflow and temperature situations that occurred through the Ring inlet. Improving air velocity improved mean efficiency from 7–8% at 0.5 m/s to nearly 16–17% at 1.5 m/s, while raising temperature from 30 to 90 °C increased average efficiency from approximately 9–10% to 16%. Sand mass had a relatively non-monotonic effect at 200 g, giving peak average efficiency of approximately (13.6%): Lower and higher masses presented low performance due to lower thermal contacts as well as higher pressure losses, respectively. In general, the Ring inlet exhibited a better electrical output than the Straight inlet, increasing the electrical output by some 25% under the same conditions of the Straight as a whole, indicating how crucial inlet design is for coupled thermo-fluid systems. This concept of the optimal operating window – high airflow, high temperature, and moderate sand loading – serves as a practical guideline to design compact energy recovery devices with fluidized granular media.
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Abdelmagied, M. (2024). Thermo-fluid characteristics and exergy analysis of a twisted tube helical coil. Sci Rep, 14(1), 27873. https://doi.org/10.1038/s41598-024-78164-1
Abdelrehim, O., Awad, A. M., Hegazi, A. A., El-Said, E. M. S., & Khater, A. (2024). Innovative enhancements in solar still performance: A comprehensive study on wick-absorber configurations. Case Studies in Thermal Engineering, 63. https://doi.org/10.1016/j.csite.2024.105273
Acharya, S., Karanth, K. V., Kumar, S., & H․ S․, A. (2025). Thermo-fluid analysis of a spring fin turbulator placement on the absorber plate of the solar air heater. International Journal of Thermofluids, 30. https://doi.org/10.1016/j.ijft.2025.101444
Agati, G., Franchetti, B., Rispoli, F., & Venturini, P. (2024). Thermo-fluid dynamic analysis of the air flow inside an indoor vertical farming system. Applied Thermal Engineering, 236. https://doi.org/10.1016/j.applthermaleng.2023.121553
Alrashidi, A., Abdo, S., Abdelrahman, M. A., Altohamy, A. A., & Elsemary, I. M. M. (2025). Investigating the effectiveness of hydrogels for PV cooling across different operational conditions: An experimental approach. Case Studies in Thermal Engineering, 75. https://doi.org/10.1016/j.csite.2025.107125
Atiqur Rahman, M., Mozammil Hasnain, S. M., & Zairov, R. (2025). Thermo-Hydraulic Performance of Tubular Heat Exchanger with Opposite-Oriented Trapezoidal Wing Perforated Baffle Plate. Tehnički glasnik, 19(3), 350-358. https://doi.org/10.31803/tg-20230928070645
Baccoli, R., Di Meglio, A., Fenu, A., & Massarotti, N. (2025). Design and performance of a ThermoAcoustic Electric Generator powered by waste-heat based on linear and nonlinear modelling. Applied Thermal Engineering, 276. https://doi.org/10.1016/j.applthermaleng.2025.126938
Behzad, M., Poncet, S., & Sarmiento-Laurel, C. (2025). Multi-objective optimization on thermo-structural performance of honeycomb absorbers for concentrated solar power systems. Case Studies in Thermal Engineering, 70. https://doi.org/10.1016/j.csite.2025.106068
Bianco, N., Fragnito, A., Iasiello, M., & Mauro, G. M. (2023). A CFD multi-objective optimization framework to design a wall-type heat recovery and ventilation unit with phase change material. Applied Energy, 347. https://doi.org/10.1016/j.apenergy.2023.121368
Catalán-Martínez, D., Navarrete, L., Tarach, M., Santos-Blasco, J., Vøllestad, E., Norby, T.,…Serra, J. M. (2022). Thermo-fluid dynamics modelling of steam electrolysis in fully-assembled tubular high-temperature proton-conducting cells. International Journal of Hydrogen Energy, 47(65), 27787-27799. https://doi.org/10.1016/j.ijhydene.2022.06.112
Claussner, L. M., Scarponi, G. E., & Ustolin, F. (2025). Thermo-Fluid Dynamics Modelling of Liquid Hydrogen Storage and Transfer Processes. Hydrogen, 6(4). https://doi.org/10.3390/hydrogen6040122
Dhaundiyal, A., & Atsu, D. (2022). The effect of thermo-fluid properties of air on the solar collector system. Alexandria Engineering Journal, 61(4), 2825-2839. https://doi.org/10.1016/j.aej.2021.08.015
Di Meglio, A., & Massarotti, N. (2022). CFD Modeling of Thermoacoustic Energy Conversion: A Review. Energies, 15(10). https://doi.org/10.3390/en15103806
Di Meglio, A., Massarotti, N., & Piccolo, A. (2024). Experimental validation of a heat exchanger model for thermoacoustic applications. Journal of Physics: Conference Series, 2685(1). https://doi.org/10.1088/1742-6596/2685/1/012014
Fu, Y., Shan, G., Zhang, X., Zhao, L., & Yang, Y. (2025). Design and Fabrication of Embedded Microchannel Cooling Solutions for High-Power-Density Semiconductor Devices. Micromachines (Basel), 16(8). https://doi.org/10.3390/mi16080908
Guille, A., Mohankumar, M. B., Hampel, U., & Unger, S. (2026). Thermo-fluid and economic performance of PCHEs in a high-temperature thermal energy storage system coupled with an sCO2 Brayton cycle. International Journal of Heat and Mass Transfer, 256. https://doi.org/10.1016/j.ijheatmasstransfer.2025.127918
Jiao, K., Ma, B., Liu, X., Chen, B., Wang, Q., & Zhao, C. (2024). Advances in 3D Materials‐Based Hydrovoltaic Generators and Synergistic Energy Conversion. ChemElectroChem, 11(20). https://doi.org/10.1002/celc.202400330
Kwasi-Effah, C. C., Ibhadode, O., & Qureshi, A. (2024). Thermo-hydraulic performance characteristics of novel G-Prime and FRD Triply Periodic Minimal Surface (TPMS) geometries. International Communications in Heat and Mass Transfer, 159. https://doi.org/10.1016/j.icheatmasstransfer.2024.108226
Mezzacapo, A., D’Addio, R., & De Stefano, G. (2025). A Computational Thermo-Fluid Dynamics Simulation of Slot Jet Impingement Using a Generalized Two-Equation Turbulence Model. Energies, 18(14). https://doi.org/10.3390/en18143862
Persico, G., Romei, A., Gaetani, P., Bellobuono, E. F., Toni, L., & Valente, R. (2024). Thermo-fluid dynamic modeling of a supercritical carbon dioxide compressor for waste heat recovery applications. Energy, 294. https://doi.org/10.1016/j.energy.2024.130874
Rahman, M. A. (2024a). Thermo-fluid performance of a heat exchanger with a novel perforated flow deflector type conical baffles. Journal of Thermal Engineering, 868-879. https://doi.org/10.14744/thermal.0000846
Rahman, M. A. (2024b). Thermo-fluid performance of axially perforated multiple rectangular flow deflector-type baffle plate in an tubular heat exchanger. Applications in Engineering Science, 20. https://doi.org/10.1016/j.apples.2024.100197
Rostami, S., & Ahmadi, N. (2025). In the Study of the Effects of the Pipe Design of a Heat Exchanger on the Thermo-Fluid Characteristics and Exergy Destruction. Processes, 13(3). https://doi.org/10.3390/pr13030835
Sahrane, S., & Niou, S. (2025). Evaluating turbulence models for accurate thermo-fluid simulation in sthe with combined tube bundles. Turkish Journal of Engineering, 9(2), 258-271. https://doi.org/10.31127/tuje.1546393
Sarkar, S. (2024). Computational Thermo-Fluid Dynamics Modeling for Process Optimization in Hydrogen-Integrated Industrial Heat Systems. Journal of Sustainable Development and Policy, 03(03), 87-133. https://doi.org/10.63125/8rm6bc88
Shimada, Y., Watanabe, N., Ueno, A., & Nagano, H. (2024). Evaluation of evaporative heat transfer performance based on observation of Thermo-Fluid behavior in porous structures fabricated by additive manufacturing. Thermal Science and Engineering Progress, 56. https://doi.org/10.1016/j.tsep.2024.103081
Starace, G., Falcicchia, L., Panico, P., Fiorentino, M., & Colangelo, G. (2021). Experimental performance comparison between circular and elliptical tubes in evaporative condensers. Journal of Thermal Analysis and Calorimetry, 147(11), 6363-6373. https://doi.org/10.1007/s10973-021-10968-z
Toor, Z., Bahaidarah, H. M., Zayed, M. E., Rehman, S., Khanna, V., & Shalaby, S. M. (2026). Experimental investigation and CFD modeling on rooftop vertical axis wind turbine for sustainable residential buildings: development of core design optimization and advanced performance analysis. Energy and Buildings, 353. https://doi.org/10.1016/j.enbuild.2025.116901
Xiao, Y., Wu, X., Tong, X., Chen, E., & Zhang, C. (2025). Reproducible Thermo-Fluid–Solid-Coupled Modeling of Wet Milling of Al6061: Parametric Influence and Surface Integrity Assessment. Metals, 15(11). https://doi.org/10.3390/met15111256