Document Type : Original Article

Authors

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

Abstract

In the present paper, the use of radiating gas instead of air inside the cavity of compound parabolic collectors (CPSs) is suggested and verified by numerical analysis. The collector under study has a simple cone shape with flat absorber which is filled with a participating gas such as carbon dioxide instead of air for the purpose of increasing the thermal performance. In numerical simulation, the continuity, momentum and energy equations for the steady natural convection laminar gas flow in the CPC’s cavity and the conduction equation for glass cover and absorber plate were solved by the finite element method (FEM) using the COMSOL multi-physics. Because of the radiative term in the gas energy equation, the intensity of radiation in participating gas flow should be computed. Toward this end, the radiative transfer equation (RTE) was solved by the discrete ordinate method (DOM), considering both diffuse and collimated radiations. The  approximation was employed in calculation of the diffuse part of radiation. It was observed that the gas radiation causes high temperature with more uniform distribution inside the cavity of collector. Also, numerical results reveal more than 3% increase in the rate of heat transfer from absorber surface into working fluid and hence a desired performance for the collector because of the gas radiation effect.  Comparison between the present numerical results with theoretical and experimental data reported in the literature showed good consistency.

Keywords

1.     Rojas, G. B., Rondon, R. L. A. and Gurrola, A. C. M. 2018. “Mechanical Engineering Design Theory Framework for Solar Desalination Processes: A Review and Meta-Analysis.” Iranian (Iranica) Journal of Energy and Environment, 9(2), pp.137–145. https://doi.org/10.5829/IJEE.2018.09.02.09
2.     Premkumar, S., Ramanarasimha, K. and Prakash, E. S. 2018. “Design and Development of Solar Crop Dryer Integrated with Oil Bath.” Iranian (Iranica) Journal of Energy and Environment, 9(4), pp.277–283. https://doi.org/10.5829/IJEE.2018.09.04.08
3.     Junfeng, L. and Runqing, H. 2005. “Solar thermal in China.” Refocus, 6(5), pp.25–27. https://doi.org/10.1016/S1471-0846(05)70454-6
4.     Nnamchi, S. N., Nnamchi, O. A., Sangotayo, E. O., Ismael, S. A., Nkurunziza, O. K. and Gabriel, V. 2020. “Design and Simulation of Air-Solar Preheating Unit: An Improved Design of a Flat Plate Solar Collector.” Iranian (Iranica) Journal of Energy and Environment, 11(2), pp.97–108. https://doi.org/10.5829/IJEE.2020.11.02.02
5.     Xu, D. and Qu, M. 2013. “Compound Parabolic Concentrators in Solar Thermal Applications: A Review.” In ASME 2013 7th International Conference on Energy Sustainability. American Society of Mechanical Engineers. https://doi.org/10.1115/ES2013-18409
6.     Francesconi, M., Caposciutti, G. and Antonelli, M. 2018. “CFD optimization of CPC solar collectors.” Energy Procedia, 148, pp.551–558. https://doi.org/10.1016/j.egypro.2018.08.138
7.     Reichl, C., Hengstberger, F. and Zauner, C. 2013. “Heat transfer mechanisms in a compound parabolic concentrator: Comparison of computational fluid dynamics simulations to particle image velocimetry and local temperature measurements.” Solar Energy, 97, pp.436–446. https://doi.org/10.1016/j.solener.2013.09.003
8.     Eames, P. C. and Norton, B. 1993. “Detailed parametric analyses of heat transfer in CPC solar energy collectors.” Solar Energy, 50(4), pp.321–338. https://doi.org/10.1016/0038-092X(93)90027-L
9.     Chew, T. C., Tay, A. O. and Wijeysundera, N. E. 1989. “A Numerical Study of the Natural Convection in CPC Solar Collector Cavities with Tubular Absorbers.” Journal of Solar Energy Engineering, 111(1), pp.16–23. https://doi.org/10.1115/1.3268281
10.   Bhusal, Y., Hassanzadeh, A., Jiang, L. and Winston, R. 2020. “Technical and economic analysis of a novel low-cost concentrated medium-temperature solar collector.” Renewable Energy, 146, pp.968–985. https://doi.org/10.1016/j.renene.2019.07.032
11.   Ma, G., Yin, Z., Liu, X., Qi, J. and Dai, Y. 2021. “Developments of CPC solar evacuated glass tube collector with a novel selective coating.” Solar Energy, 220, pp.1120–1129. https://doi.org/10.1016/j.solener.2020.08.052
12.   Atashafrooz, M., Gandjalikhan Nassab, S. A. and Lari, K. 2016. “Numerical analysis of interaction between non-gray radiation and forced convection flow over a recess using the full-spectrum k-distribution method.” Heat and Mass Transfer, 52(2), pp.361–377. https://doi.org/10.1007/s00231-015-1561-z
13.   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). https://doi.org/10.1115/1.4044756
14.   Dehghani Rayeni, A. and Gandjalikhan Nassab, S. A. 2020. “Effects of Gas Radiation on Thermal Performances of Single and Double Flow Plane Solar Heaters.” International Journal of Engineering - Transactions C: Aspects, 33(6), pp.1156–1166. https://doi.org/10.5829/ije.2020.33.06c.14
15.   Modest, M. 2003. Radiative Heat Transfer, 2nd Edition. Academic Press.
16.   Terrón-Hernández, M., Peña-Cruz, M., Carrillo, J., Diego-Ayala, U. and Flores, V. 2018. “Solar Ray Tracing Analysis to Determine Energy Availability in a CPC Designed for Use as a Residential Water Heater.” Energies, 11(2), pp.291. https://doi.org/10.3390/en11020291
17.   Chabane, F., Moummi, N. and Brima, A. 2018. “Experimental study of thermal efficiency of a solar air heater with an irregularity element on absorber plate.” International Journal of Heat and Technology, 36(3), pp.855–860. https://doi.org/10.18280/ijht.360311