Dimensional characteristics of wind effects on the performance of indirect dry cooling system with vertically arranged heat exchanger bundles

Yang, Linlin; Wu, X.P.; Du, Xiaoze; Yang, Yongping

doi:10.1016/j.ijheatmasstransfer.2013.08.085

Cited by 113 publications

(93 citation statements)

References 10 publications

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“…The computational domain of the model is usually cylindrical or cubic shaped. In order to avoid the unrealistic effect of the domain boundaries on the flow field, the computation domain is usually more than 10 times larger than the diameter of the cooling tower and more than 6 times larger than the cooling tower height [38,39,56].…”

Section: Cfd Simulationmentioning

confidence: 99%

“…For the NDDCTV, the thermal performance is believed to be more susceptible to the crosswind than those with horizontal arranged heat exchanger [38,44,49,57,70,75,76]. For this kind of NDDCT where the vertically oriented heat exchanger panels are distributed around the tower perimeter with direct exposure to crosswind, the mechanism of crosswind effect are totally different.…”

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

“…For this kind of NDDCT where the vertically oriented heat exchanger panels are distributed around the tower perimeter with direct exposure to crosswind, the mechanism of crosswind effect are totally different. NDDCTV in windless condition [38]. Similar to the NDDCT with horizontal arranged heat exchanger, a uniform distributed temperature and velocity profile can be achieved inside the cooling tower.…”

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

“…can cause extra air flow though the heat exchangers. According to Yang and Zhao's simulation [38,57], the air mass flow rate in the windward section is the largest and increases continuously with 31 increased crosswind speed. For the side section, the aerodynamic performance is like the flow over a vertical cylinder [36].…”

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

“…Compared with high ambient temperatures, crosswind effects are much more complex and harder to predict. It has been reported that for a NDDCT, the thermal performance of the tower could drop significantly and certain parts of the cooling tower may even stop functioning under crosswind conditions [36][37][38][39]. The crosswind has a less but still significant effect on wet cooling towers.…”

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: Cfd Simulationmentioning

confidence: 99%

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

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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Rotational speed adjustment of axial flow fans to maximize net power output for direct dry cooling power generating units

Chen

Sun

Yang

et al. 2019

Heat Trans. Asian Res.

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The power consumption of axial flow fans may account for more than 1% of the rated power output of the power generating unit, so it is of benefit to the energy efficiency of the power generating unit to propose an operation adjustment approach to axial flow fans. On the basis of representative 2 × 600 MW direct dry cooling generating units, a computational model of air-side flow and heat transfer of an air-cooled condenser (ACC) combined with exhaust steam condensation is developed, by which the airflow rate, inlet air temperature of ACCs, the power consumption of axial flow fans, turbine backpressure, and net power output of power generating units at various wind speeds and in various wind directions are obtained. The results show that the net power output in the presence of winds always decreases when the rational speeds of the first upwind row axial flow fans increase from the rated speed of 79 rpm by 10% to 86.9 rpm. However, the net power output will increase in various wind directions if the rational speeds of all the fans except the upwind first row fans increase to 86.9 rpm. This can contribute to the optimal operation of the ACC by rotational speed adjustment of axial flow fans. K E Y W O R D S air-cooled condenser, axial flow fan, backpressure, power generating unit, power output, rotational speed regulation | 361

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Operation strategies of axial flow fans in a direct dry cooling system under various meteorological conditions

et al. 2021

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For a direct dry cooling system, the turbine back pressure fluctuates with the meteorological conditions. Moreover, the operation of axial flow fans plays an important role in the cooling performance of air‐cooled condensers (ACC). It is of significant use to study the operation strategies of axial flow fans under various ambient conditions. Based on typical 2 × 660 MW direct dry cooling power generating units, the ACC model coupled with the turbine thermodynamic characteristics is developed, by which the thermo‐flow performances of the ACC are predicted in the dominant wind direction, and then the standard coal consumption is calculated. The results show that the increased ambient temperature and wind speed, or the reduced fan rotational speed leads to the high turbine back pressure. At the low ambient temperature and wind speed, the standard coal consumption rate of the unit can be reduced by reducing the speed of axial flow fans appropriately, with the maximum drop in coal consumption rate reached 0.734 g/(kWh) when the ambient temperature is 10°C without wind. If the wind speed exceeds 12 m/s or the ambient temperature reaches 25°C, 110% of the rated fan rotational speed is recommended.

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Dimensional characteristics of wind effects on the performance of indirect dry cooling system with vertically arranged heat exchanger bundles

Cited by 113 publications

References 10 publications

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

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

Rotational speed adjustment of axial flow fans to maximize net power output for direct dry cooling power generating units

Operation strategies of axial flow fans in a direct dry cooling system under various meteorological conditions

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