Abstract
Purpose
In this study, a conical solar concentrating system using a glass cover on the absorber is proposed to improve thermal efficiency and reduce convective heat loss. The purpose of covering the absorber with a glass tube is to restrict the direct contact of ambient air with the absorber surface. To increase the surface area of the absorber, a copper coil was inserted between the inner and outer tubes.
Methods
Using the aforementioned two configurations, a series of experiments was performed with variable fluid flow rates and similar climatic conditions. To locate the optimal performance of the conical concentrator system, different fluid flow rates were tested such as 2 L/min, 4 L/min, 6 L/min, and 8 L/min. As a result of the performance test of the conical concentrator system according to the change of ambient air, it showed the highest efficiency at a critical flow rate of 6 L/min, and the heat collecting efficiency of the conical concentrator with the glass cover absorber was 4.15%p higher than that of the double coil absorber.
Results
The performance test of the conical concentrator according to the difference between the inlet temperature and the ambient temperature, when (Ti − Ta)/I is 0 at 6 L/min, the heat collection efficiency of the double coil absorber and the glass cover absorber was 81.66% and 81.05%. The reason for the low heat collecting efficiency is that the loss from the transmittance, absorption, and reflectance of sunlight due to the glass cover is greater than the loss of convective heat at a 0℃ difference.
Conclusions
The difference between the inlet temperature and the ambient air temperature increased, and the overturn phenomenon occurred. As the temperature difference increased, the heat-collecting efficiency of the conical concentrator with the glass cover absorber was higher. The highest heat-collecting efficiency of a conical concentrator with a glass cover absorber can be interpreted as the low heat losses to ambient air due to the presence of a glass cover.
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References
Alsalame, H. A. M., Hussain, M. I., Amjad, W., Ali, A., & Lee, G. H. (2022). Thermo-economic performance evaluation of a conical solar concentrating system using coil-based absorber. Energies, 15(9), 3369. https://doi.org/10.3390/en15093369
Choi, B. W., & Yang, Y. J. (2014). Study on Thermal efficiency according to configuration change and contact resistance of solar collector with single evacuated tube-type. Korean Society for Energy, 23(4), 189–195. https://doi.org/10.5855/ENERGY.2014.23.4.189
Do, S. J., & Yang, Y. J. (2018). Evaluation of solar collector to introduce natural convection in water tank to obtain warm water. The Korean Society of Manufacturing Process Engineers, 17(2), 22–29. https://doi.org/10.14775/ksmpe.2018.17.2.022
Farzan, H., Zaim, E. H., & Ameri, M. (2020). Study on the effect of glazing on performance and heat dynamics of asphalt solar collectors: An experimental study. Solar Energy, 202, 429–437. https://doi.org/10.1016/j.solener.2020.04.003
Hwang, J. Y. (2017). Experimental and numerical study on the performance of conical solar collector system. Unpublished MS thesis. Kangwon National University.
Hwang, S. G. (2020). A study on the enhancement of thermal efficiency of conical concentrator using nanofluids. Unpublished MS thesis. Kangwon National University.
Kim, K. S., Kang, G. H., & Yoo, G. J. (2008). The analysis of optical characteristics of glasses for PV module application. The Korean Solar Energy Society, 98–103. https://koreascience.kr/article/CFKO200835536015389.page
Kim, J. H., Kang, J. G., & Kim, J. T. (2009). Experimental performance comparison of water type glazed and unglazed PV-thermal combined collectors. Korea Institute of Ecological Architecture and Environment, 9(4), 37–42. https://koreascience.kr/article/JAKO200930360545063.page
Kim. & Choi Jun-bo. (2011). Development and market prospects of low iron high transmittance float glass. Korean Ceramic Society, 14(6), 34–41. https://koreascience.kr/article/JAKO201111436237488.pdf
Lee, J. H. (2020). A study on the efficiency improvement of photovoltaic-thermal system using nanofluids. Unpublished MS thesis. Kangwon national university.
Mahmood, A. H. A. (2021). Efficiency improvement of the conical solar concentrator system with the coil absorber. Unpublished MS thesis. Kangwon national university.
Na, M. S. (2018). Agricultural dryer for energy saving with conical solar concentrating system. Unpublished MS thesis. Kangwon national university.
Na, M. S., Hwang, J. Y., Hwang, S. G., Lee, J. H., & Lee, G. H. (2018). Design and performance analysis of conical solar concentrator. Journal of Biosystems Engineering, 43(1), 21–29. https://doi.org/10.5307/JBE.2018.43.1.021
Park, J. Y., & Kim, Y. J. (2019). The effects of renewable energy in agricultural sector. Journal of the Korea Academia-Industrial Cooperation Society, 20(1), 224–235. https://doi.org/10.5762/KAIS.2019.20.1.224
Soudani, M. E., Aiadi, K. E., Bechki, D., & Chihi, S. (2017). Experimental and theoretical study of Parabolic trough collector (PTC) with a flat glass cover in the region of algerian sahara (Ouargla). Journal of Mechanical Science and Technology, 31(8), 4003–4009. https://doi.org/10.1007/s12206-017-0747-3
Toğrul, İT., & Pehlıvan, D. (2003). The performance of a solar air heater with a conical concentrator under forced convection. International Journal of Thermal Sciences, 42(6), 571–581. https://doi.org/10.1016/S1290-0729(03)00023-1
Funding
This work was supported by the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, and Forestry (IPET) through the Technology Commercialization Support Program, funded by the Ministry of Agriculture, Food, and Rural Affairs (MAFRA) (No. 821048–3).
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Alsalame, H.A.M., Cho, J.M. & Lee, G.H. Effects of the Glass Cover Absorber for Conical Solar Concentrator on the Thermal Collecting Efficiency. J. Biosyst. Eng. 48, 79–92 (2023). https://doi.org/10.1007/s42853-022-00170-w
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DOI: https://doi.org/10.1007/s42853-022-00170-w