A study of the unfavorable effects of wind on the cooling efficiency of dry cooling towers

Qing-ding, Wei; Zhang, Bo-yin; Liu, Ke-qi; Du, Xiangdong; Meng, Xiandong

doi:10.1016/0167-6105(94)00078-r

Cited by 108 publications

(77 citation statements)

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“…In these above full-scale measurements, thermal performances of the NDDCTVs were observed to monotonously decrease with increasing crosswind speed. However, a reverse trend was observed in lab-scale tests [45] and some numerical modelling studies [38,39,71]. For example, in Yang's research [38], the cooling performance of a 195 m NDDCTV was investigated in different crosswind conditions and a critical wind speed of 12 m/s is observed.…”

Section: Aerodynamic Behaviours and Heat Exchanger Performancementioning

confidence: 99%

“…Apart from the two lab-scale experiments, all other studies listed in Table 2 Wei [45] observed that the outlet water temperature could go up by 25% when crosswind speed increased to 6 m/s. More detailed data was reported by Ardenikani [84] on a 92m NDDCTV.…”

Section: Aerodynamic Behaviours and Heat Exchanger Performancementioning

confidence: 99%

“…In the isothermal tests [44][45][46][47][48], the densimetric Fr is neglected and the natural draft effect is modelled by using mechanical fans. The mechanical fans can be installed at the top of the cooling tower, at the throat of the cooling tower or at the bottom of the cooling tower.…”

Section: Lab-scale Model Measurementsmentioning

confidence: 99%

“…They proposed the possible reasons for the reduction of cooling tower heat diffusion under crosswind conditions as the low-pressure effect at the side of the cooling tower, the formation of the air vortex inside the cooling tower and wind-cover effect at the top of the cooling tower. Wei et al [45] presented the experimental data of a 125 m NDDCT at the crosswind speed of 6 m/s. Their results indicate the wind reducing the efficiency of the dry cooling tower and increasing the average temperature of the heat exchanger by 5 °C.…”

Section: Introductionmentioning

confidence: 99%

“…The influence of the crosswind has received significant attention in the last few decades [45,76,130].…”

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: Aerodynamic Behaviours and Heat Exchanger Performancementioning

confidence: 99%

Section: Aerodynamic Behaviours and Heat Exchanger Performancementioning

confidence: 99%

Section: Lab-scale Model Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The influence of the crosswind has received significant attention in the last few decades [45,76,130].…”

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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Dry Cooling Towers for Geothermal Power Plants

Guan¹,

Hooman²,

Gurgenci³

2016

Alternative Energy and Shale Gas Encyclopedia

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Design of efficient dry cooling system is of critical importance for geothermal power conversion technologies. In fact, dry cooling may be the only option for most geothermal power plants planned to be established in areas with limited access to water. The heat exchange performance, flow geometry optimisation and cost are key factors in determining suitability of dry cooling towers for geothermal power plants.China has made advances in recent years in R&D, manufacturing, and utilisation of dry cooling towers in its coal rich but water scarce Northern provinces.One driver for the surge in applications of dry cooling systems is the government regulation that requires all new coalfired power plants built in Northern China region to use dry cooling systems. Northern China has plenty of coal but no water for wet cooling in its coal-fired power plants.A straightforward copying of the technology from coal-fired power industry to geothermal power industry is not expected to deliver a cost-effective solution and should be avoided. Benefits would be gained by reviewing the development of dry cooling technologies in Chinese coal-fired power plants.The Queensland Geothermal Energy Centre of Excellence (QGECE) has supported Dr Zhiqiang Guan to apply for the Queensland International Fellowship aiming to review the advance of the dry cooling technology in China. In this paper a summary of dry cooling technology will be given with a focus on the Chinese practice.

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Research on the Effect of Cross-wind to Temperature Difference and Efficiency of Natural Draft Counter flow Wet Cooling Tower

Gao

Sun

Shi³

et al. 2007

Challenges of Power Engineering and Environment

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A study of the unfavorable effects of wind on the cooling efficiency of dry cooling towers

Cited by 108 publications

References 0 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

Dry Cooling Towers for Geothermal Power Plants

Research on the Effect of Cross-wind to Temperature Difference and Efficiency of Natural Draft Counter flow Wet Cooling Tower

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