• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.3
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• pp.130-136
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• 2014

The present study is performed to set up the framework of cooling tower performance predictions. The performance of mechanical forced draft cooling tower is directly related to the state of a nuclear power plant system, such as the condenser and evaporator. The main parameters related to the state of systems are as follows : wet bulb temperature, dry bulb temperature and absolute humidity. The performance evaluation of cooling tower must be considered at the power plant design. In this study, the toolkit developed by the American Cooling Tower Industry association (CTI) has been used for the framework construction. In order to validate the framework, it is being applied to the cooling tower constructed for the U.S. Nuclear Power Plant. The test results have shown good agreements with the cold water temperature on the cooling tower performance curves provided by manufacturers.

• Journal of Yeungnam Medical Science
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• v.5 no.1
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• pp.77-84
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• 1988

The principal mode of the transmission of Legionnaires disease is a inthalation of the cooling tower water droplets in which Legionellae exist. As a central cooling system is popularized in many public buildings and large buildings nowadays, the number of cooling towers is rapidly increasing. Therefore the possibility of an outbreak of Legionnaires disease is likely increased. To determine the presence of Legionella in cooling tower water as the first step for the prevention of Legionnaires disease, 48 samples of cooling tower water were taken from 24 buildings in Taegu city in july and september 1987. Three samples out of 24 water samples In September yielded Legionella but it was not isolated in the samples of July. Isolated 3 Legionellas were identified as Legionella peumophila. It seems that Legionella from the cooling tower will be isolated more frequently in late summer than early because central cooling system is stopped operation during winter season which is cool. As based on our survey, Legionnaires disease can occur in Taegu city and if it happens it is most likely due to L. pneumophila.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.528-533
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• 2008

A closed circuit cooling tower having high temperature of cooling water and small water flow rate is investigated. To study the characteristics of the heat transfer of heat exchanges in a cooling tower with multi paths a numerical method is used. The results show that the staggered tube arrangements in a bank show better performance than aligned ones for temperature variation with various outer diameters of tube bundles. In case of one pass, the 15.88 mm tube case shows about 9% better performance than the 25.4 mm tube case. In two paths, the tube outside diameter of 15.88 mm show about 14.4% better results than the 25.4 mm diameter case.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.598-604
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• 1999

The thermal performance of cooling towers is affected by the temperature of inlet water, wet bulb temperature of entering air add water-air flow rate. In this study, the effects of these variables are simulated using NTU-method and experimentally investigated for the counter-flow cooling towers. The simulation program to evaluate these variables which affect the performance of cooling tower was developed. The maximum errors between the results of simulations and experiments were 3.8% under the standard design conditions and 5.4% under the other conditions. The performance was increased up to 46~50% as the water loading was increased from $6.8m^3$/$hr\cdot m^2$ to $15.9m^3$/$hr\cdot m^2$. The range was reduced up to 56~42% when the wet bulb temperature of the entering air was increased from $22^{\circ}C\; to\; 29^{\circ}C.$

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.597-602
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• 2008

The experiment of performance about closed-wet cooling tower(CWCT) was conducted in this study. The test section has the cooling water that flows from top part of a heat exchanger that has an entrance of cooling water with one and multi path. The heat exchanger consists of 15.88mm tubes with ten rows and ten columns and staggered arrangement. In this experiment, heat and mass transfer coefficients and range are calculated with variations of cooling water and path. The results indicated that operating CWCT using two path have the high values of heat and mass transfer coefficients and range than one path.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.3
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• pp.267-273
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• 2013

In order to provide effective operating conditions for the fan in a wet cooling tower with film fill, a new program to search for the minimum fan power was developed using a model of the optimal total annual cost of the tower based on Merkel's model. In addition, a type of design map for a cooling tower was also developed. The inlet water temperature and heat load were considered as key parameters. The present program was first validated using several typical examples. The results showed that for a given heat load, a three-dimensional graph of the fan power (z-axis), mass flux of air (x-axis, minimum fan power), and inlet water temperature (y-axis, maximum of minimum fan power) showed a saddle configuration. The minimum fan power increased as the heat load increased. The conventionally known fact that the most effective cooling tower operation coincides with a high inlet water temperature and low air flow rate can be replaced by the statement that there exists an optimum mass flux of air corresponding to a minimum fan power for a given inlet water temperature, regardless of the heat load.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.1018-1027
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• 2003

This study treats the analysis of the performance and the design of plume abatement wet/dry cooling tower with dry type heat exchanger using a numerical method. A two-dimensional analysis is performed using the finite volume method for mechanical draft counterflow and crossflow tower. For a coupling problem between water and air system, a turbulent two phase flow is considered. Effectiveness-NTU method is used for modeling of the dry type heat exchanger. The parameter change simulations of the outer wall shape, the relative flowrate of air, and attachment of an air mixer are performed to examine the effect on plume abatement. It is found that if the relative air flowrate ratio and the adequate air mixer type are chosen well in addition to the ratio of water to air flowrate, the loss of the cooling capacity and the additional cost are reduced and the plume is abated.

• International Journal of Air-Conditioning and Refrigeration
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• v.13 no.2
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• pp.61-70
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• 2005

This study treats the numerical analysis of performance and design for plume abatement wet/dry cooling tower with a dry type heat exchanger. A two-dimensional analysis is performed using the finite volume method for mechanical draft counterflow and crossflow tower. For a coupling problem between water and air system, a turbulent two phase flow is considered. The Effectiveness-NTU method is used for modeling of the dry type heat exchanger. The parametric simulations such as the relative flowrate of air and attachment length of an air mixer are performed to examine the effect on plume abatement. It is found that if the relative air flowrate ratio and the adequate air mixer type are chosen well in addition to the ratio of water to air flowrate, the loss of cooling capacity and the additional cost are reduced and the plume is abated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.535-549
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• 1998

A numerical study for performance analysis of a counterflow type forced draft tower and natural draft cooling tower has been performed based on the method using the finite volume method with non-orthogonal body fitted and non-staggered grid system. For solving the coupling problem between water and air, air enthalpy balance, moisture fraction balance, water enthalpy balance, and water mass balance equations are solved with Navier-Stoke’s equations simultaneously. For the effect of turbulence, the standard k-$\varepsilon$ turbulent model is implied in this analysis. The predicted result of the present analysis is compared with the experimental data and the commercial software result to validate the present study, The predicted results show good agreement with the experimental data and the commercial software result. To investigate the influence of the cooling tower design parameters such as approach, range and wet bulb temperature, parametric studies are also peformed.

• Membrane and Water Treatment
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• v.10 no.5
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• pp.321-330
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• 2019

The objective of this study was to examine the recovery of the power plant cooling tower blowdown water (CTBD) by membrane distillation. The experiments were carried out using a flat plate poly vinylidene fluoride (PVDF) membrane with a pore diameter of $0.22{\mu}m$ by a direct contact membrane distillation unit (DCMD). The effects of operating parameters such as transmembrane temperature difference (${\Delta}T$), circulation rate and operating time on permeate flux and membrane fouling have been investigated. The results indicated that permeate flux increased with increasing ${\Delta}T$ and circulation rate. Whereas maximum permeate flux was determined as $47.4L/m^2{\cdot}h$ at ${\Delta}T$ of $50^{\circ}C$ for all short term experiments, minimum permeate flux was determined as $7.7L/m^2{\cdot}h$ at ${\Delta}T$ of $20^{\circ}C$. While $40^{\circ}C$ was determined as the optimum ${\Delta}T$ in long term experiments. Inorganic and non-volatile substances caused fouling in the membranes.