Experimental study of crosswind effects on the performance of small cylindrical natural draft dry cooling towers

Lu, Yuanwei; Guan, Zhiqiang; Gurgenci, Hal; Hooman, Kamel; He, Suoying; Bharathan, D.

doi:10.1016/j.enconman.2014.12.018

Cited by 73 publications

(51 citation statements)

References 18 publications

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“…However, the second method can be applied in the lab-scale tests and numerical modelling where the cooling tower can be made to run with constant hot water inlet temperature. pronounced in short cooling towers [6,42,56,73,74]. If we refer to the speed at which the crosswind effect starts reversing as the critical speed, for a 20 m cooling tower, the critical wind speed is about 5 m/s [79].…”

Section: Crosswind Effect On the Nddcthmentioning

confidence: 99%

“…Secondly, the recirculation vortex formed at the windward part of the cooling tower starts helping the heat dump at higher wind speeds instead of merely obstructing the flow as observed at lower speeds. Finally, when a cooling tower with horizontal arranged heat exchangers is subjected to the crosswind, the heat can be taken away off the bottom surface of the heat exchanger by the horizontal airflow [42,73].…”

Section: Crosswind Effect On the Nddcthmentioning

confidence: 99%

“…According to the previous research [26,38,42,64,68,71,131], the realizable k-ε model has been selected in this study. The general term of the governing equations can be expressed as:…”

Section: Governing Equationsmentioning

confidence: 99%

“…12 Wind tunnel in Gatton campus of The University of Queensland In the non-isothermal tests [41][42][43], small air-cooled heat exchanger or electronic heaters are used to model the air-cooled heat exchanger in the real cooling tower. The natural draft effect can be demonstrated in such tests.…”

Section: Lab-scale Model Measurementsmentioning

confidence: 99%

“…Al-Waked and Benhia's study on crosswind was however limited to tall towers used in large thermal power plants. Lu et.al [56,74] The Queensland Geothermal Energy Centre of Excellence (QGECE) has been developing the small size NDDCT for CST and geothermal power generation systems [6,42,56,74]. This research is necessary because the existing NDDCT design is optimised for large stream power plant, and is not optimal for a CST plant.…”

Section: Introductionmentioning

confidence: 99%

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Numerical and experimental study of small natural draft dry cooling tower for concentrating solar thermal power plant

Li¹

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The typically arid climates in the likely locations for renewable thermal power plants such as Concentrating Solar Thermal (CST) power plants provide the motivation for dry cooling technology applications. Natural draft dry cooling tower (NDDCT) with low maintenance cost and no parasitic power consumption offers a feasible and cost effective option for such applications. Compared with the conventional coal fired and nuclear power plants, the size of the CST power plant proposed for Australian regional communities is much smaller. However, the existing cooling tower design is optimised for large steam power plants, and is not optimal for these renewable power plants. (2) The performance of the experimental tower was tested at two constant heat loads of 600 kW and 840 kW, respectively, with various ambient temperatures. The 1D numerical model was refined and validated with the experimental data. The thermodynamic model of a 1 MW CST power plant running with sCO2 cycle was developed and integrated with the updated cooling tower model. Significant differences were observed between the steam Rankine and sCO2 cycles in terms of the effect of the ambient temperature on power generation. The differences between steam Rankine and sCO2 Brayton cycle in this context were analysed and discussed.(3) Two potential cooling issues with small NDDCT, the crosswind and the cold inflow, were identified and the detail experimental data were presented. The crosswind effect on small cooling tower is different from the conventional big cooling towers. With the increase of the crosswind speed, the overall cooling performance of the small NDDCT first decreases and then increases. The mixed convection theory and the Richardson Number were proposed to explain this phenomenon. On the other hand, repeated cold inflow events were observed during the tests, which cause a significant decrease of the air temperature inside the cooling tower. The water outlet temperature can be increased up to 3°C as a result of the cold inflow effect. Further analysis of the mechanism shows that the cold air incursion at the top of the cooling tower could decrease the driving force and also form an extra flow resistance for the airflow through the heat exchanger.(4) Based on the working mechanism of the air-cooled heat exchanger and the crosswind effect on NDDCT, this study proposed a new method to increase the cooling performance of NDDCT under crosswind conditions by optimizing the water mass flow rate in the air-cooled heat exchangers. By optimising the water distribution, the water outlet temperature of each heat exchanger is more uniform and the adversely influence of the crosswind can be effectively relieved.The findings in this paper can lay an important foundation for future small cooling tower design and operation.

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Section: Crosswind Effect On the Nddcthmentioning

confidence: 99%

Section: Crosswind Effect On the Nddcthmentioning

confidence: 99%

“…According to the previous research [26,38,42,64,68,71,131], the realizable k-ε model has been selected in this study. The general term of the governing equations can be expressed as:…”

Section: Governing Equationsmentioning

confidence: 99%

Section: Lab-scale Model Measurementsmentioning

confidence: 99%