International Scientific Journal

Thermal Science - Online First

online first only

Investigation of the performance of cold-end system in direct air-cooled power units under the influence of ambient winds

Direct air-cooled condensers in power plants rely on heat transfer with the atmospheric environment to discharge thermal energy. The heat transfer process becomes complicated in practical operations when ambient wind is involved. To examine the impact of wind on the heat transfer performance of direct air-cooled condensers, this paper took into consideration three different wind directions, namely, headwind, crosswind and tailwind, as well as four different speeds (3 m/s, 6 m/s, 9 m/s, and 12 m/s), and numerically investigated their influences on the thermal performance of a 600 MW direct air-cooled power unit. The variation in ventilation rates and inlet air temperatures among the cells under the influence of ambient winds are also studied. Simulation results indicated that ambient winds induced thermal air recirculation and air backflow phenomena in the air-cooled island. The cells located on the windward side were significantly affected in all three wind direction conditions. The ventilation rates and inlet air temperatures among the cells were not uniform, showing an overall increasing trend. In particular, negative pressure zones were generated under tailwind conditions, severely impacting air flow rates at the fan inlet, and inlet air temperatures of cells. These phenomena became more pronounced with increasing wind speeds.
PAPER REVISED: 2023-09-20
PAPER ACCEPTED: 2023-11-30
  1. Lakovic, M., et al., Impact of the cold end operating conditions on energy efficiency of the steam power plants, Thermal Science, 14 (2010), suppl., pp. 53-66
  2. Li, X., et al., A data-driven model for the air-cooling condenser of thermal power plants based on data reconciliation and support vector regression, Applied Thermal Engineering, 129 (2018), pp. 1496-1507
  3. Lin, X., et al., Cold-end integration of thermal system in a 1000 MW ultra-supercritical double reheat power plant, Applied Thermal Engineering, 193 (2021), pp. 116982
  4. Luo Z., et al., Energy-efficient operation of a direct air-cooled condenser based on divisional regulation, International Journal of Refrigeration, 132 (2021), pp. 233-242
  5. Yang, T., et al., Closed-loop optimization control on fan speed of air-cooled steam condenser units for energy saving and rapid load regulation, Energy, 135 (2017), pp. 394-404
  6. Zhu M., et al., Dynamic modeling, validation and analysis of direct air-cooling condenser with integration to the coal-fired power plant for flexible operation, Energy Conversion and Management, 245 (2021), pp. 114601
  7. He, W. F., et al., Performance prediction of an air-cooled steam condenser using UDF method, Applied Thermal Engineering, 50 (2013), 1, pp. 1339-1350
  8. Klimeš, L., et al., Semi-empirical balance-based computational model of air-cooled condensers with the A-frame layout, Energy, 182 (2019), pp.1013-1027
  9. Deng, H. Liu, J. Performance Prediction of Finned Air-Cooled Condenser Using a Conjugate Heat-Transfer Model, Applied Thermal Engineering, 150 (2019), pp. 386-397
  10. Zhang, Y., et al., Dynamic modeling and control of direct air-cooling condenser pressure considering couplings with adjacent systems, Energy, 236 (2021), pp. 121487
  11. Zheng, G., et al., Cluster Partition Operation Study of Air-Cooled Fan Groups in a Natural Wind Disturbance, Energies, 16 (2023), 9, pp. 3717
  12. Gao, X. F., et al., Performance prediction of an improved air-cooled steam condenser with deflector under strong wind, Applied Thermal Engineering, 30 (2010), 17, pp. 2663-2669
  13. Chen, L., et al., A novel layout of air-cooled condensers to improve thermo-flow performances, Applied Energy, 165 (2016), 165, pp. 244-259
  14. Mahvi, A. J., et al., Challenges in predicting steam-side pressure drop and heat transfer in air-cooled power plant condensers, Applied Thermal Engineering, 133 (2018), pp. 396-406
  15. Li, X. E., et al., Identification of optimal operating strategy of direct air-cooling condenser for Rankine cycle based power plants, Applied Energy, 209 (2018), 153, pp. 153-166
  16. Jin, Y., et al., Analysis of joint operation of air-cooling system and peak cooling device in summer, Applied Thermal Engineering, 188 (2021), pp. 116635
  17. Pieve, M., Salvadori. G., Performance of an air-cooled steam condenser for a waste-to-energy plant over its whole operating range, Energy Conversion and Management, 52 (2011), 4, pp. 1908-1913
  18. Feng, P., Luo, Z., Back pressure optimization of direct air-cooled condenser considering anti-freezing and low-load operation, IOP Conference Series: Materials Science and Engineering, 569 (2019), pp. 032029-
  19. Deng, H., et al., Numerical investigation on complete condensation and freezing of finned tube air-cooled condensers, Applied Thermal Engineering, 168 (2020), 5, pp.114428
  20. Li, J., et al., Operation of air cooled condensers for optimised back pressure at ambient wind, Applied Thermal Engineering, 128 (2018), pp. 1340-1350
  21. Xiao, L., et al., Operation of air-cooling CHP generating unit under the effect of natural wind, Applied Thermal Engineering, 107 (2016), pp. 827-836
  22. Xiao, L., et al., Air-cooling condenser layout of 2×1000MW direct air-cooled units under effect of ambient natural wind, Electric Power Construction, 36 (2015), 6, pp. 7-13 (in Chinese)
  23. Luo, Z., Yao, Q., Multi-Model-Based Predictive Control for Divisional Regulation in the Direct Air-Cooling Condenser, Energies, 15 (2022), 13, pp. 4803
  24. Ma, H., et al., Numerical study identifies the interaction between two adjacent dry cooling towers on fluid flow and heat transfer performances of the radiators at different points of each tower, International Journal of Thermal Sciences, 191 (2023), pp. 108351
  25. Yang, L., et al., Numerical investigation on the cluster effect of an array of axial flow fans for air-cooled condensers in a power plant, Chinese Sci Bull, 56 (2011), 21, pp. 2272-2280 (in Chinese)
  26. Yang, L. J., et al., Space characteristics of the thermal performance for air-cooled condensers at ambient winds, International Journal of Heat and Mass Transfer, 54 (2011), 15, pp. 3109-3119
  27. Li, M., et al., Correction algorithm for calculating heat transfer in air-cooling condenser based on analyzing steam condensation locations, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 45 (2023), 3, pp. 6744-6755
  28. Hu, H., Research on flow and heat transfer of finned heat exchanger of direct-cooled condenser and flow characteristic of condenser unit, M.S. thesis, Chongqing University, Chongqing , CHN, 2006
  29. Chen, L., et al., Rotational speed adjustment of axial flow fans to maximize net power output for direct dry cooling power generating units, Heat Transfer-Asian Research, 49 (2020), 1, pp. 356-382
  30. Chen, L., et al., Subregional modulation of axial flow fans to reduce condensate supercooling of air-cooled steam condenser in cold days, Applied Thermal Engineering, 193 (2021), pp. 117016
  31. Zhu, X., Zhan, J., Operation optimization of cold‐end system of direct air‐cooled units considering the effect of environmental wind, Heat Transfer, 52 (2023), 06, pp. 4337-4356