Impact of Collector Slope on Power Output and System Efficiency in Solar Chimney Power Plants

Öz

In this study, impact of collector slope on the system is analysed with 3D CFD model developed based on Manzanares prototype. In the numerical model, DO (discrete ordinates) radiation model for solar load and RNG k-ε turbulence model for turbulent air flow in the system are simultaneously utilised. Maximum air velocity within the system for incoming solar radiation of    1000 W/m2 is determined to be 14.3 m/s, which agrees with experimental data of 15 m/s. In the Manzanares prototype, collector inlet height is given as 1.85 m. Here, collector inlet height is kept constant and the collector outlet height is configured as 2.91, 3.97, 5.04, 6.12 and 7.17 m, so the change in system performance is evaluated in cases where the collector slope is 0.5, 1, 1.5, 2 and 2.5°. Findings show that the increase in collector slope rises mass flow rate of air in the system and this improves power output of the system. Collector efficiency is 38.7% for the
horizontal collector which represents the reference case, whereas it is enhanced to 41.5% when collector slope is 1°. Power output of the system at reference case is 54.5 kW, while it is    57.1 kW when collector slope is 2.5°. 

Anahtar Kelimeler

• Solar chimney power plants
• collector slope
• power output
• system efficiency

GÜNEŞ BACASI GÜÇ SANTRALLERİNDE TOPLAYICI EĞİMİNİN ÇIKIŞ GÜCÜNE VE SİSTEM VERİMİNE ETKİSİ

Öz

Bu çalışmada toplayıcı eğiminin sisteme etkisi Manzanares prototipi esas alınarak geliştirilen 3 boyutlu CFD modeli ile analiz edilmektedir. Nümerik modelde güneş yükü için DO (discrete ordinates) ışınım modeli ve sistem içerisindeki hava hareketi için RNG k-ε türbülans modeli birleştirilerek uygulanmaktadır. 1000 W/m2 güneş ışınımında sistemdeki maksimum hız 14.3 m/s olarak bulunurken bu değer deneysel veri olan 15 m/s ile uyum içerisindedir. Manzanares prototipinde toplayıcı giriş yüksekliği 1.85 m olarak verilmektedir. Bu çalışma kapsamında toplayıcı giriş yüksekliği sabit tutularak, toplayıcı çıkış yüksekliği sırası ile 2.91, 3.97, 5.04, 6.12 ve 7.17 m olarak tasarlanmakta ve bu sayede toplayıcı eğiminin 0.5, 1, 1.5, 2 ve 2.5° olduğu durumlarda sistemin performansındaki değişim değerlendirilmektedir. Elde edilen sonuçlar toplayıcı eğimindeki artışın sistemdeki hava hareketinin kütlesel debisini arttırdığını ve bu artışın sistemin güç çıkışını iyileştirdiğini göstermektedir. Referans durumu temsil eden eğimsiz toplayıcı için toplayıcı verimi %38.7 iken toplayıcı eğimi 1° olduğunda verimin %41.5’e iyileştiği gözlenmektedir. Sistemin çıkış gücü referans durumda 54.5 kW iken toplayıcı eğimi 2.5° olduğunda 57.1 kW olarak belirlenmektedir.

Anahtar Kelimeler

• Güneş bacası güç santralleri
• toplayıcı eğimi
• çıkış gücü
• sistem verimi

Kaynakça

1. 1. Ahirwar, M.J. ve Sharma, P. (2019) Analyzing the Effect of Solar Chimney Power Plant by Varying Chimney Height, Collector Slope and Chimney Diverging Angle, International Journal of Innovative Research in Technology, 6(7), 213-219.
2. 2. Al Alawin, A., Badran, O., Awad, A., Abdelhadi, Y. ve Al-Mofleh, A. (2012) Feasibility study of a solar chimney power plant in Jordan, Applied Solar Energy, 48(4), 260-265. doi: 10.3103/S0003701X12040020
3. 3. Bayareh, M. (2017) Numerical simulation of a solar chimney power plant in the southern region of Iran, Energy Equipment and Systems, 5(4), 431-437. doi:10.22059/EES.2017.28979
4. 4. Cuce, E., Sen, H., ve Cuce, P.M. (2020) Numerical performance modelling of solar chimney power plants: Influence of chimney height for a pilot plant in Manzanares, Spain, Sustainable Energy Technologies and Assessments, 39, 100704.
5. 5. Esfinadi, M.T., Raveshi, S., Shahsavari, M. ve Sedaghat, A. (2015) Computational study on design parameters of a solar chimney, International Conference on Sustainable Mobility Applications, Renewables and Technology, Kuwait, 1-5. doi:10.1109/SMART.2015.7399268
6. 6. Haaf, W., Friedrich, K., Mayr, G. ve Schlaich, J. (1983) Solar chimneys part I: principle and construction of the pilot plant in Manzanares, International Journal of Solar Energy, 2(1), 3-20. doi: 10.1080/01425918308909911
7. 7. Haaf, W. (1984) Solar chimneys: part ii: preliminary test results from the Manzanares pilot plant, International Journal of Sustainable Energy, 2(2), 141-161. doi:10.1080/01425918408909921
8. 8. Hassan, A., Ali, M. ve Waqas, A. (2018) Numerical investigation on performance of solar chimney power plant by varying collector slope and chimney diverging angle, Energy, 142, 411-425. doi:10.1016/j.energy.2017.10.047

9. 9. Hoseini, H. ve Mehdipour, R. (2018) Evaluation of solar-chimney power plants with multipleangle collectors, Journal of Computational and Applied Research in Mechanical Engineering, 8(1), 85-96. doi:10.22061/JCARME.2017.2282.1213
10. 10. Hu, S., Leung, D.Y.C. ve Chen MZQ. (2017) Effect of divergent chimneys on the performance of a solar chimney power plant, Energy Procedia, 105, 7-13. doi:10.1016/j.egypro.2017.03.273
11. 11. Kalantar, V. ve Zare, M. (2011) Simulation of flow and heat transfer in 3D solar chimney power plants-numerical analysis, Jordan International Energy Conference, Amman, Jordan.
12. 12. Khelifi, C., Ferroudji, F. ve Ouali, M. (2016) Analytical modeling and optimization of a solar chimney power plant, International Journal of Engineering Research in Africa, 25, 78-88. doi: 10.4028/www.scientific.net/JERA.25.78
13. 13. Larbi, S., Bouhdjar, A. ve Chergui, T. (2010) Performance analysis of a solar chimney power plant in the southwestern region of Algeria, Renewable and Sustainable Energy Reviews, 14(1), 470-477. doi:10.1016/j.rser.2009.07.031
14. 14. Li, J., Guo, H. ve Huang, S. (2016) Power generation quality analysis and geometric optimization for solar chimney power plants, Solar Energy, 139, 228-237. doi:10.1016/j.solener.2016.09.033
15. 15. Ming, T., Richter, R.K., Meng, F., Pan, T. ve Liu, W. (2013) Chimney shape numerical study for solar chimney power generating systems, International Journal of Energy Research, 37(4), 310-322. doi:10.1002/er.1910
16. 16. Mullett, L.B. (1987) The solar chimney overall efficiency, design and performance, International Journal of Ambient Energy, 8(1), 35-40. doi:10.1080/01430750.1987.9675512
17. 17. Rabehi, R., Chaker, A., Aouachria, Z. ve Tingzhen, M. (2017) CFD analysis on the performance of a solar chimney power plant system: Case study in Algeria, International Journal of Green Energy, 14(12), 971-982. doi.org/10.1080/15435075.2017.1339043
18. 18. Schlaich, J. (1995) The solar chimney: electricity from the sun, Edition Axel Menges, Stuttgart, Germany.
19. 19. Sen, H., ve Cuce, E. (2020) Dynamic pressure distributions in solar chimney power plants: A numerical research for the pilot plant in Manzanares, Spain, WSSET Newsletter, 12(1), 2-2.
20. 20. Tingzhen, M., Wei, L. ve Guoliang, X. (2006) Analytical and numerical investigation of the solar chimney power plant systems, International Journal of Energy Research, 30, 861-873. doi.org/10.1002/er.1191
21. 21. Toghraie, D., Karami, A., Afrand, M. ve Karimipour, A. (2018) Effects of geometric parameters on the performance of solar chimney power plants, Energy, 162, 1052-1061. doi:10.1016/j.energy.2018.08.086
22. 22. Zandian, A. ve Ashjaee, M. (2013) The thermal efficiency improvement of a steam Rankine cycle by innovative design of a hybrid cooling tower and a solar chimney concept, Renewable Energy, 51, 465-473. doi:10.1016/j.renene.2012.09.051
23. 23. Zhou, X., Yang, J., Xiao, B., Hou, G. ve Xing, F. (2009) Analysis of chimney height for solar chimney power plant, Applied Thermal Engineering, 29, 178-185. doi:10.1016/j.applthermaleng.2008.02.014