On the influence of psychrometric ambient conditions on cooling tower drift deposition

Lucas, M.; Martínez, Pedro García; Ramírez, Javier Ruiz; Kaiser, Antonio Sánchez; Viedma, A.

doi:10.1016/j.ijheatmasstransfer.2009.10.037

Cited by 49 publications

(14 citation statements)

References 10 publications

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“…Computational Fluids Dynamics (CFD) is a suitable tool for estimating drift, droplet evaporation and deposition in cooling towers zones (Takata et al [2], Riddle et al [3]). In the work of Lucas et al [4], a study of the influence of psychometric ambient conditions on cooling tower drift is carried out by means of CFD tools. Meroney [5] presented numerical results for the cooling tower dispersion and drift downwind the cooling tower.…”

Section: Introductionmentioning

confidence: 99%

Prediction of the lifetime of droplets emitted from mechanical cooling towers by numerical investigation

Sánchez

Kaiser

Parra

et al. 2015

International Journal of Heat and Mass Transfer

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A numerical modelling capable to simulate the drift and the evaporation of water droplets emitted by a mechanical cooling tower in an urban area is presented. The model is based on a real mechanical draft cooling tower situated in the surroundings of the Miguel Hernández University (Elche, Spain). An experimental study of the deposition of droplets from the cooling tower is done in order to validate the numerical modelling. This study is performed by means of the water sensitive papers technique. A biharmonic interpolation is used for obtaining the total deposition on the floor. A total of 14 cases, everyone with different atmospheric conditions, have been simulated and experimentally validated. An analytical model for the droplets lifetime prediction is validated with the results obtained from the numerical modelling. The present study shows the influence of the atmospheric and droplets conditions in the droplets lifetime, providing useful information to analyse the spread of contaminants or bacteria inside the droplets released from the cooling tower.

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Section: Introductionmentioning

confidence: 99%

Prediction of the lifetime of droplets emitted from mechanical cooling towers by numerical investigation

Sánchez

Kaiser

Parra

et al. 2015

International Journal of Heat and Mass Transfer

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“…The air flow field was described by the Reynolds-averaged Navier-Stokes conservation equations (RANS) combined with the standard k-ε model to account for the turbulence effects [28]. The governing equations of the airflow are given in the Eulerian modelling as [29]:…”

Section: Continuous Phasementioning

confidence: 99%

A study on multi-nozzle arrangement for spray cooling system in natural draft dry cooling tower

Sun

Guan

Gurgenci

et al. 2017

Applied Thermal Engineering

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Natural draft dry cooling tower (NDDCT) technology is especially attractive to power plants built in arid regions with limited water resource. However, high ambient temperature in summer deteriorates the performance of built NDDCT. To address this problem, evaporative pre-cooling technology has been developed by using nozzles to disintegrate water into fine droplets to achieve quick evaporation. The pre-cooled air flowing through radiator, has an enhanced heat exchange with the hot working fluid in the tube side. This paper reports a spray cooling system for the experimental tower built in UQ by combining several nozzle LNN1.5 to cool the inlet air and consequently improve the cooling efficiency of the NDDCT. To minimize water usage, a careful arrangement of spray nozzles should be investigated to achieve the maximum cooling outcome. With five nozzles installment, the inlet air is cooled by 6.3 ºC, corresponding to 51.2% cooling efficiency. A dimensionless analysis is presented to correlate cooling efficiency with influencing factors. The advantage of this pre-cooling system lies in the efficient water usage: more than 96% of the injected water extracts substantial heat from hot air and evaporates into vapor, leading to a pre-cooled airflow.

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“…All numerical calculations were run first using the pressure-based steady-state solver with SIMPLE segregated algorithms and second-order discretization [53]. The convergence criterion in each calculation was for all scaled residuals of the dependent variables to drop to the order of 10 -4 [69] and remain invariable afterwards. In addition, the integral variables monitored also remained stable when iterating.…”

Section: Governing Equations and Solvermentioning

confidence: 99%

Small natural draft dry cooling towers for renewable power plants

Lu¹

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In thermal power plants using variety of heat sources, the redundant heat needs to be removed through cooling devices such as heat exchangers and cooling towers. Natural draft dry cooling towers (NDDCTs) feature no water loss and no parasitic power consumption during operation and are widely used in thermal power plants around the world, especially in arid areas. The Queensland Geothermal Energy Centre of Excellence (QGECE) is focusing on developing small-or mediumscale engineered geothermal system (EGS) geothermal and concentrated solar thermal (CST) power plants for Australia. The proposed renewable power plants are most likely to be located in arid remote areas where dry cooling is the only cost-effective option. These power plants may initially be introduced to supply remote communities away from the national grid. Such off-grid applications are expected to be relatively small reflecting the size of the demand. The aim of this Thesis project is to investigate whether natural draft dry cooling towers (NDDCTs) can be used for these small-or medium-scale renewable power plants.Crosswind is the most common factor affecting the cooling performance of natural draft cooling towers. But current NDDCT design procedures do not take the crosswind effect into account. It is probably not a critical impediment for large towers as the negative influence of the crosswind is negligible when the draft heights are above 100 m. On the other hand, in small NDDCTs with total heights less than 30 m, the crosswind effect could be substantial.A numerical study was carried out to investigate the thermal performance of the horizontally arranged heat exchangers in small NDDCTs under various crosswind conditions. In particular, a 15 m-high CFD NDDCT model was constructed and simulated to examine the crosswind actions in detail. It was found that at certain crosswind speeds the cooling tower performance can be considerably reduced. A very effective mitigation device, a tri-blade-like windbreak wall, has been found to dramatically improve the cooling performance of the small tower. The effect of the windbreak was sensitive to its orientation with respect to the crosswind direction.An experimental study was conducted with a 1:12.5 scaled natural draft dry cooling tower model in the wind tunnel. The thermal performance of the scaled tower was measured with and without the windbreak wall. The experimental results verified the numerical predictions for the small tower cooling performance and the effectiveness of the windbreak wall.The most important finding of this study is that the total heat transfer in a small natural draft cooling tower is a combination of the heat transfer by both natural convection and forced convection, with the contribution of the latter increasing at higher crosswind speeds. A simple correlation between II the heat transfer and the crosswind speed was proposed to estimate the crosswind-affected thermal performance of natural draft dry cooling towers at different sizes and with horizontal heat exchanger arrang...

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On the influence of psychrometric ambient conditions on cooling tower drift deposition

Cited by 49 publications

References 10 publications

Prediction of the lifetime of droplets emitted from mechanical cooling towers by numerical investigation

Prediction of the lifetime of droplets emitted from mechanical cooling towers by numerical investigation

A study on multi-nozzle arrangement for spray cooling system in natural draft dry cooling tower

Small natural draft dry cooling towers for renewable power plants

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