Document Type : Original Article

Authors

Department of Mechanical Engineering, School of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran

Abstract

A new idea is presented in this paper for improving the performance of solar air heater (SAH) designed for space heating by employing a thin flexible guide winglet. In addition to the role of winglet in pushing the convective airflow toward the heated surface, it behaves as a vortex generator (VG) due to its vibration by fluid-solid interaction (FSI) that causes flow mixing and breaking thermal boundary layer. In flow simulation, the finite element method (FEM) is employed with considering a two-way strongly-coupled FSI approach at transient condition. Numerical solution of the governing equations, including the continuity, momentum and energy for convective flow and the equation of motion for VG are obtained by COMSOL multi-physics. The well-known  model is employed for computation of turbulent stress and heat flux. The present numerical results are validated against the most recent relevant literature. To provide a clear and deep understanding of the proposed concept, extensive comparisons are made between different test cases. Results reveal considerable performance enhancement of SAH with elastic guide winglet compared with clean solar air heater (CSAH), such that 56% increase in the natural airflow rate and 9% decrease in the average absorber temperature is seen because of the flapping winglet. But, the air outlet temperature decreases about 14% due to flapping VG.  This study aims to make the proposed SAH as an essential renewable thermal-solar system more efficient and attractive so that this improvement pushes the industrial society toward more sustainable infrastructure.

Keywords

1.   Gill, R. S., Singh, S., and Singh, P. P. 2012. “Low cost solar air heater.” Energy Conversion and Management, 57, pp.131–142. https://doi.org/10.1016/j.enconman.2011.12.019
2.   Tuncer, A. D., Khanlari, A., Sözen, A., Gürbüz, E. Y., Şirin, C., and Gungor, A. 2020. “Energy-exergy and enviro-economic survey of solar air heaters with various air channel modifications.” Renewable Energy, 160, pp.67–85. https://doi.org/10.1016/j.renene.2020.06.087
3.   Aramesh, M., Ghalebani, M., Kasaeian, A., Zamani, H., Lorenzini, G., Mahian, O., and Wongwises, S. 2019. “A review of recent advances in solar cooking technology.” Renewable Energy, 140, pp.419–435. https://doi.org/10.1016/j.renene.2019.03.021
4.   Kalogirou, S. A. 2004. “Solar thermal collectors and applications.” Progress in Energy and Combustion Science, 30(3), pp.231–295. https://doi.org/10.1016/j.pecs.2004.02.001
5.   Kabeel, A. E., Hamed, M. H., Omara, Z. M., and Kandeal, A. W. 2017. “Solar air heaters: Design configurations, improvement methods and applications – A detailed review.” Renewable and Sustainable Energy Reviews, 70(November 2015), pp.1189–1206. https://doi.org/10.1016/j.rser.2016.12.021
6.   Singh, A. P., and Singh, O. P. 2019. “Thermo-hydraulic performance enhancement of convex-concave natural convection solar air heaters.” Solar Energy, 183(October 2018), pp.146–161. https://doi.org/10.1016/j.solener.2019.03.006
7.   Singh, S. 2020. “Experimental and numerical investigations of a single and double pass porous serpentine wavy wiremesh packed bed solar air heater.” Renewable Energy, 145, pp.1361–1387. https://doi.org/10.1016/j.renene.2019.06.137
8.   Fan, W., Kokogiannakis, G., and Ma, Z. 2019. “Optimisation of life cycle performance of a double-pass photovoltaic thermal-solar air heater with heat pipes.” Renewable Energy, 138, pp.90–105. https://doi.org/10.1016/j.renene.2019.01.078
9.   Singh, A. P., and Singh, O. P. 2020. “Curved vs. flat solar air heater: Performance evaluation under diverse environmental conditions.” Renewable Energy, 145, pp.2056–2073. https://doi.org/10.1016/j.renene.2019.07.090
10. Bensaci, C.-E., Moummi, A., Sanchez de la Flor, F. J., Rodriguez Jara, E. A., Rincon-Casado, A., and Ruiz-Pardo, A. 2020. “Numerical and experimental study of the heat transfer and hydraulic performance of solar air heaters with different baffle positions.” Renewable Energy, 155, pp.1231–1244. https://doi.org/10.1016/j.renene.2020.04.017
11. Priyam, A., and Chand, P. 2018. “Effect of wavelength and amplitude on the performance of wavy finned absorber solar air heater.” Renewable Energy, 119, pp.690–702. https://doi.org/10.1016/j.renene.2017.12.010
12. Arunkumar, H. S., Kumar, S., and Karanth, K. V. 2020. “Analysis of a solar air heater for augmented thermohydraulic performance using helicoidal spring shaped fins-A numerical study.” Renewable Energy, 160, pp.297–311. https://doi.org/10.1016/j.renene.2020.06.098
13. Kumar, A., and Layek, A. 2019. “Nusselt number and friction factor correlation of solar air heater having twisted-rib roughness on absorber plate.” Renewable Energy, 130, pp.687–699. https://doi.org/10.1016/j.renene.2018.06.076
14. Thakur, D. S., Khan, M. K., and Pathak, M. 2017. “Performance evaluation of solar air heater with novel hyperbolic rib geometry.” Renewable Energy, 105, pp.786–797. https://doi.org/10.1016/j.renene.2016.12.092
15. Jin, D., Quan, S., Zuo, J., and Xu, S. 2019. “Numerical investigation of heat transfer enhancement in a solar air heater roughened by multiple V-shaped ribs.” Renewable Energy, 134, pp.78–88. https://doi.org/10.1016/j.renene.2018.11.016
16. Rai, S., Chand, P., and Sharma, S. P. 2016. “Investigation of an Offset Finned Solar Air Heater Based on Energy and Exergy Performance.” Iranian (Iranica) Journal of Energy and Environment, 7(3), pp.212–220. https://doi.org/10.5829/idosi.ijee.2016.07.03.01
17. Rayeni, A. D., and Nassab, S. A. G. 2020. “Effects of Gas Radiation on Thermal Performances of Single and Double Flow Plane Solar Heaters.” International Journal of Engineering, Transaction C: Aspects, 33(6), pp.1156–1166. https://doi.org/10.5829/ije.2020.33.06c.14
18. Foruzan Nia, M., Gandjalikhan Nassab, S. A., and Ansari, A. B. 2020. “Numerical Simulation of Flow and Thermal Behavior of Radiating Gas Flow in Plane Solar Heaters.” Journal of Thermal Science and Engineering Applications, 12(3), pp.1–8. https://doi.org/10.1115/1.4044756
19. Sheikhnejad, Y., and Gandjalikhan Nassab, S. A. 2021. “Enhancement of solar chimney performance by passive vortex generator.” Renewable Energy, 169, pp.437–450. https://doi.org/10.1016/j.renene.2021.01.026
20. Ali, S., Menanteau, S., Habchi, C., Lemenand, T., and Harion, J.-L. 2016. “Heat transfer and mixing enhancement by using multiple freely oscillating flexible vortex generators.” Applied Thermal Engineering, 105, pp.276–289. https://doi.org/10.1016/j.applthermaleng.2016.04.130
21. Li, Z., Xu, X., Li, K., Chen, Y., Huang, G., Chen, C., and Chen, C.-H. 2018. “A flapping vortex generator for heat transfer enhancement in a rectangular airside fin.” International Journal of Heat and Mass Transfer, 118, pp.1340–1356. https://doi.org/10.1016/j.ijheatmasstransfer.2017.11.067
22. La Pica, A., Rodonò, G., and Volpes, R. 1993. “An experimental investigation on natural convection of air in a vertical channel.” International Journal of Heat and Mass Transfer, 36(3), pp.611–616. https://doi.org/10.1016/0017-9310(93)80036-T
23. Singh, A. P., Akshayveer, Kumar, A., and Singh, O. P. 2019. “Designs for high flow natural convection solar air heaters.” Solar Energy, 193(August), pp.724–737. https://doi.org/10.1016/j.solener.2019.10.010
24. Le Tallec, P., and Mouro, J. 2001. “Fluid structure interaction with large structural displacements.” Computer Methods in Applied Mechanics and Engineering, 190(24–25), pp.3039–3067. https://doi.org/10.1016/S0045-7825(00)00381-9
25. Cheng, X., and Müller, U. 1998. “Turbulent natural convection coupled with thermal radiation in large vertical channels with asymmetric heating.” International Journal of Heat and Mass Transfer, 41(12), pp.1681–1692. https://doi.org/10.1016/S0017-9310(97)00303-7