| The cooling tower is one of the important cold equipment in thermal power plant.The performance of the cooling tower has a significant impact on the safety and economy of the power generation system.The wet cooling tower consumes a large amount of water,and its application area needs abundant water sources,while the operation of the air cooling requires almost no water consumption.Therefore,the natural draft dry cooling tower(NDDCT)has become the main direction of power development in arid areas.However,the cooling efficiency of the NDDCT is extremely low during the high temperature period in summer,and the peak power consumption is at this time,so the research and analysis of the dry cooling system is very urgent and necessary.In this study,the solar enhanced natural draft dry cooling tower(SENDDCT)was studied in depth to explore the feasibility of the application of the SENDDCT in typical areas.In this paper,a 3D numerical model of the SENDDCT with a vertical height of 140 meters was established,and the model was solved by using the software ANSYS FLUENT.By comparing the simulation results with the results in the literature,the applicability of the model was verified.The validated model was used to explore the comprehensive impact of ambient temperature and solar radiation intensity on the performance of the SENDDCT,as well as the influence of shadow occlusion in practical production applications.In order to improve the cooling efficiency of the SENDDCT in the high temperature period in summer,this paper proposed to change the shape of heat storage layer of the heat collection shed from a plane to a corrugated,rectangular and zigzag shape.The influence of the surface shape of the heat storage layer on the cooling performance of the SENDDCT was explored by means of numerical simulation,and an analysis of the three different shapes of the heat storage layer of the SENDDCT was also made.Through the comparison analysis,the effect of different surface shape of the heat storage layer on the cooling performance of the solar energy enhanced air cooling tower was obtained,which provided a reference for the optimization of the SENDDCT.For the SENDDCT with vertical arrangement of heat exchanger,the research results revealed that:(1)under the combined influence of environment temperature and solar radiation intensity,the heat emission of solar energy enhanced air cooling tower decreases gradually in daytime;(2)without considering shadow,the heat emission of solar energy enhanced air cooling tower is always higher than that of shadow,the maximum difference between the two is 12.2 MW(7.8%)and the minimum difference is 4.6 MW(4.1%).The simulation results showed that when the ambient temperature was 303.15 K,the inlet water temperature was 333.15 K,and the solar radiation intensity was 1000 W/m2,the surface of the heat storage layer was changed from plane to corrugated,rectangular and zigzag,and the heat dissipation rate of the cooling tower is increased from 132.9mw to 145.3,149.2 and 150.2 MW,increased by 9.3%,12.3%and 13.0%,respectively.It can be seen that the cooling performance of the three kinds of SENDDCT with the shape of heat storage layer had been improved.At the ambient temperature of 303.15 K,the solar radiation intensity was 1000 W/m2,the inlet water temperature was 323.15,328.15 and 333.15K,for the cooling performance of the SENDDCT with corrugated,rectangular and zigzag heat storage layer,the zigzag heat storage layer had the best improvement effect on the performance of the SENDDCT,followed by the rectangle,and the corrugated shape is the worst.The zigzag outlet water temperature is 312.2,315.2,318.1 K,the rectangular outlet water temperature is 312.4,315.2,318.2 K,and the corresponding outlet water temperature of the corrugated tower is 313.2,315.8 and 318.6 K,which further verifies that the shape of the heat storage layer with the best cooling performance of the cooling tower is zigzag.The research in this paper can provide a reference for the practical application of the SENDDCT,and provide a direction for further optimization of the SENDDCT. |
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