Advanced Cooling Tower Concept for Commercial and Industrial Applications

2014 ◽  
Author(s):  
Sergey Anisimov ◽  
Aleksandr Kozlov ◽  
Paul Glanville ◽  
Mark Khinkis ◽  
Valeriy Maisotsenko ◽  
...  
Keyword(s):  
Cooling Tower ◽  
Industrial Applications ◽  
Process Efficiency ◽  
Limiting Factor ◽  
Cooling Towers ◽  
Water Stream ◽  
Cooling Performance ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler ◽  
The U.S

For the majority of cooling towers installed, of which there are greater than half a million installed in the U.S., tower design uses direct evaporative cooler technology where an ideally enthalpy-neutral process cools the process water stream to a temperature above the ambient wet bulb. This ambient wet bulb temperature is the limiting factor for the process cooling. As such the energy-water connection is clear, these cooling towers are direct consumers of treated water and their cooling performance is intimately tied to the process efficiency.

Numerical Simulations of Heat and Mass Transfer Process of a Direct Evaporative Cooler From a Porous Layer

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Karima Sellami ◽  
M'barek Feddaoui ◽  
Nabila Labsi ◽  
Monssif Najim ◽  
Youb Khaled Benkahla
Keyword(s):  
Porous Medium ◽  
Porous Layer ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Mass Transfer Process ◽  
High Porosity ◽  
Ambient Conditions ◽  
Cooling Performance ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler

This paper deals with the numerical study of the combined heat and mass exchanges in the process of direct evaporative cooler, from a porous media of laminar air flow between two parallel insulated walls. The numerical model implements momentum, energy, and mass conservation equations of humid air and water flow incorporating non-Darcian model in the porous region. The finite volume method is used for the mathematical model resolution, and the velocity–pressure coupling is treated with the SIMPLE algorithm. The main objective of this study is to examine the influences of ambient conditions and the porous medium properties (porosity and porous layer thickness) on the direct evaporative cooling performance from a porous layer. The major results of this study demonstrate that the porous evaporative wall could, in a satisfying manner, reduce the bulk air temperature. The better cooling performance can be achieved for lower air mass flow at the entrance and relative humidity. Additionally, the evaporative cooler is more effective for a high porosity and a thick porous medium, with an improvement achieving 23% for high porosity.

Simulation of a Direct Evaporative Cooler and a Cooling Tower by the Effectiveness—NTU Method

2007 ◽  
Vol 35 (3) ◽  
pp. 207-218
Author(s):  
P. A. F. Bougleux ◽  
F. E. M. Saboya ◽  
R. Pitanga Marques ◽  
J. A. R. Parise
Keyword(s):  
Heat Transfer ◽  
Engineering Students ◽  
Cooling Tower ◽  
Algebraic Equations ◽  
Simple Application ◽  
Counter Flow ◽  
One Dimensional ◽  
Transfer Equations ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler

A direct evaporative cooler and a counter-flow cooling tower were simulated by the effectiveness–NTU method. One-dimensional energy and mass balance as well as heat and mass transfer equations were applied. The resulting algebraic equations were solved numerically. To validate the simulation model, numerical results of the evaporative cooler and cooling tower were compared with available experimental data. This simple application of the effectiveness–NTU method to such important heat transfer devices may prove pedagogically useful to undergraduate mechanical engineering students attending heat transfer courses.

scholarly journals Impact of Weather Conditions on the Operation of Power Unit Cooling Towers 905 MWe

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6412
Author(s):  
Zbigniew Buryn ◽  
Anna Kuczuk ◽  
Janusz Pospolita ◽  
Rafał Smejda ◽  
Katarzyna Widera
Keyword(s):  
Power Unit ◽  
Air Temperature ◽  
Cooling Tower ◽  
Cooling Water ◽  
Weather Conditions ◽  
Cooling Towers ◽  
Cooling Efficiency ◽  
Water Cooling ◽  
Water Losses ◽  
Water Stream

The paper presents the results of measurements and calculations concerning the influence of weather conditions on the operation of wet cooling towers of 905 MWe units of the Opole Power Plant (Poland). The research concerned the influence of temperature and relative humidity of air, wind and power unit load on the water temperature at the outlet from the cooling tower, the level of water cooling, cooling efficiency and cooling water losses. In the cooling water loss, the evaporation loss stream and the drift loss stream were distinguished. In the analyzed operating conditions of the power unit, for example, an increase in Tamb air by 5 °C (from 20–22˚C to 25-27˚C) causes an increase in temperature at the outlet of the cooling tower by 3-4˚C. The influence of air temperature and humidity on the level of water cooling ΔTw and cooling efficiency ε were also found. In the case of ΔTw, the effect is in the order of 0.1-0.2˚C and results from the change in cooling water temperature and the heat exchange in the condenser. The ε value is influenced by air temperature and humidity, which determine the wet bulb temperature value. Within the range of power changes of the unit from 400 to 900 MWe, the evaporated water stream mev, depending on the environmental conditions, increases from 400-600 tons/h to the value of 1000-1400 tons/h. It was determined that in the case of the average power of the unit at the level of 576.6 MWe, the average values of the evaporation and drift streams were respectively 0.78% and 0.15% of the cooling water stream. Using statistical methods, it was found that the influence of wind on the level of water cooling, cooling efficiency and cooling water losses was statistically significant.

Case study: Theoretical calculation model and variable condition analysis research on the water-splashing noise for natural draft wet cooling towers

2020 ◽  
Vol 68 (2) ◽  
pp. 137-145
Author(s):  
Yang Zhouo ◽  
Ming Gao ◽  
Suoying He ◽  
Yuetao Shi ◽  
Fengzhong Sun
Keyword(s):  
Theoretical Model ◽  
Sound Pressure Level ◽  
Water Droplet ◽  
Water Distribution ◽  
Sound Pressure ◽  
Cooling Tower ◽  
Distribution Patterns ◽  
Calculation Model ◽  
Pressure Level ◽  
Cooling Towers

Based on the basic theory of water droplets impact noise, the generation mechanism and calculation model of the water-splashing noise for natural draft wet cooling towers were established in this study, and then by means of the custom software, the water-splashing noise was studied under different water droplet diameters and water-spraying densities as well as partition water distribution patterns conditions. Comparedwith the water-splashing noise of the field test, the average difference of the theoretical and the measured value is 0.82 dB, which validates the accuracy of the established theoretical model. The results based on theoretical model showed that, when the water droplet diameters are smaller in cooling tower, the attenuation of total sound pressure level of the water-splashing noise is greater. From 0 m to 8 m away from the cooling tower, the sound pressure level of the watersplashing noise of 3 mm and 6 mm water droplets decreases by 8.20 dB and 4.36 dB, respectively. Additionally, when the water-spraying density becomes twice of the designed value, the sound pressure level of water-splashing noise all increases by 3.01 dB for the cooling towers of 300 MW, 600 MW and 1000 MW units. Finally, under the partition water distribution patterns, the change of the sound pressure level is small. For the R s/2 and Rs/3 partition radius (Rs is the radius of water-spraying area), when the water-spraying density ratio between the outer and inner zone increases from 1 to 3, the sound pressure level of water-splashing noise increases by 0.7 dB and 0.3 dB, respectively.

scholarly journals Cooling tower plume abatement and plume modeling: a review

2021 ◽  
Author(s):  
Shuo Li ◽  
M. R. Flynn
Keyword(s):  
Public Health ◽  
Solar Energy ◽  
Cooling Tower ◽  
Plume Rise ◽  
Cooling Towers ◽  
Moist Air ◽  
Novel Technologies ◽  
Plume Modeling ◽  
Dry Cooling Tower ◽  
Dry Cooling

AbstractVisible plumes above wet cooling towers are of great concern due to the associated aesthetic and environmental impacts. The parallel path wet/dry cooling tower is one of the most commonly used approaches for plume abatement, however, the associated capital cost is usually high due to the addition of the dry coils. Recently, passive technologies, which make use of free solar energy or the latent heat of the hot, moist air rising through the cooling tower fill, have been proposed to minimize or abate the visible plume and/or conserve water. In this review, we contrast established versus novel technologies and give a perspective on the relative merits and demerits of each. Of course, no assessment of the severity of a visible plume can be made without first understanding its atmospheric trajectory. To this end, numerous attempts, being either theoretical or numerical or experimental, have been proposed to predict plume behavior in atmospheres that are either uniform versus density-stratified or still versus windy (whether highly-turbulent or not). Problems of particular interests are plume rise/deflection, condensation and drift deposition, the latter consideration being a concern of public health due to the possible transport and spread of Legionella bacteria.

Predicting cooling tower plume dispersion

1997 ◽  
Vol 211 (4) ◽  
pp. 291-297 ◽  
Author(s):  
B E A Fisher
Keyword(s):  
Cooling Tower ◽  
Industrial Process ◽  
Local Environment ◽  
Meteorological Conditions ◽  
Performance Criteria ◽  
Plume Dispersion ◽  
Cooling Towers ◽  
Atmospheric Conditions ◽  
Operating Characteristics

An assessment of the effects of visible cooling tower plumes on the local environment can be a necessary part of any proposal for a new large industrial process. Predictions of the dispersion of plumes from cooling towers are based on methods developed for chimney emissions. However, the kinds of criteria used to judge the acceptability of cooling tower plumes are different from those used for stack plumes. The frequency of long elevated plumes and the frequency of ground fogging are the two main issues. It is shown that events associated with significant plume visibility are dependent both on the operating characteristics of the tower and on the occurrence of certain meteorological conditions. The dependence on atmospheric conditions is shown to be fairly complex and simple performance criteria based on the exit conditions from the tower are not sufficient for assessments.

Design of Cooling Towers by the Effectiveness-NTU Method

1989 ◽  
Vol 111 (4) ◽  
pp. 837-843 ◽  
Author(s):  
H. Jaber ◽  
R. L. Webb
Keyword(s):  
Heat Exchanger ◽  
Cooling Tower ◽  
Design Method ◽  
Design Methods ◽  
Parallel Flow ◽  
Basic Method ◽  
Cooling Towers ◽  
Flow Configuration ◽  
Heat Exchanger Design

This paper develops the effectiveness-NTU design method for cooling towers. The definitions for effectiveness and NTU are totally consistent with the fundamental definitions used in heat exchanger design. Sample calculations are presented for counter and crossflow cooling towers. Using the proper definitions, a person competent in heat exchanger design can easily use the same basic method to design a cooling tower of counter, cross, or parallel flow configuration. The problems associated with the curvature of the saturated air enthalpy line are also treated. A “one-increment” design ignores the effect of this curvature. Increased precision can be obtained by dividing the cooling range into two or more increments. The standard effectiveness-NTU method is then used for each of the increments. Calculations are presented to define the error associated with different numbers of increments. This defines the number of increments required to attain a desired degree of precision. The authors also summarize the LMED method introduced by Berman, and show that this is totally consistent with the effectiveness-NTU method. Hence, using proper and consistent terms, heat exchanger designers are shown how to use either the standard LMED or effectiveness-NTU design methods to design cooling towers.

Analysis of Heat, Mass, and Momentum Transfer in the Rain Zone of Counterflow Cooling Towers

1999 ◽  
Vol 121 (4) ◽  
pp. 751-755 ◽  
Author(s):  
E. de Villiers ◽  
D. G. Kro¨ger
Keyword(s):  
Momentum Transfer ◽  
Cooling Tower ◽  
Mechanical Energy ◽  
Performance Evaluations ◽  
Cooling Towers ◽  
Droplet Deformation ◽  
One Dimensional ◽  
Mechanical Energy Loss ◽  
Simplifying Assumptions ◽  
Semi Empirical

The rate of heat, mass, and momentum transfer in the rain zone of three counterflow cooling tower geometries is analyzed using simplifying assumptions and numerical integration. The objective of the analysis is to generate equations for use in a one-dimensional mathematical cooling tower performance evaluations. Droplet deformation is taken into account and momentum transfer is calculated from the air flow’s mechanical energy loss, caused by air-droplet interaction. A comparison of dimensionless semi-empirical equations and experimental data demonstrates the method’s capability to predict the pressure drop in a counterflow rain zone.

scholarly journals On Thermal Performance of Seawater Cooling Towers

2010 ◽  
Author(s):  
Mostafa H. Sharqawy ◽  
John H. Lienhard ◽  
Syed M. Zubair
Keyword(s):  
Thermal Conductivity ◽  
Power Generation ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Governing Equations ◽  
Detailed Model ◽  
Salt Deposition ◽  
Transfer Processes ◽  
Mass Transfer Processes

Seawater cooling towers have been used since the 1970’s in power generation and other industries, so as to reduce the consumption of freshwater. The salts in seawater are known to create a number of operational problems including salt deposition, packing blockage, corrosion, and certain environmental impacts from salt drift and blowdown return. In addition, the salinity of seawater affects the thermophysical properties which govern the thermal performance of cooling towers, including vapor pressure, density, specific heat, viscosity, thermal conductivity and surface tension. In this paper, the thermal performance of seawater cooling towers is investigated using a detailed model of a counterflow wet cooling tower. The model takes into consideration the coupled heat and mass transfer processes and does not make any of the conventional Merkel approximations. In addition, the model incorporates the most up-to-date seawater properties in the literature. The model governing equations are solved numerically and its validity is checked by data in the literature. Based on the results of the model, a correction factor is obtained which characterizes the degradation of the cooling tower effectiveness when seawater is used.

scholarly journals Theoretical and experimental study of a cross-flow induced-draft cooling tower

2009 ◽  
Vol 13 (4) ◽  
pp. 91-98
Author(s):  
Elazm Abo ◽  
Farouk Elsafty
Keyword(s):  
Experimental Study ◽  
Cooling Tower ◽  
Characteristic Curve ◽  
Cross Flow ◽  
Hot Water ◽  
Proper Solution ◽  
Cooling Towers ◽  
Water Cooling ◽  
Transfer Coefficients ◽  
Experimental Rig

The main objective of this study is to find a proper solution for the cross-flow water cooling tower problem, also to find an empirical correlation's controlling heat and mass transfer coefficients as functions of inlet parameters to the tower. This is achieved by constructing an experimental rig and a computer program. The computer simulation solves the problem numerically. The apparatus used in this study comprises a cross-flow cooling tower. From the results obtained, the 'characteristic curve' of cross-flow cooling towers was constructed. This curve is very helpful for designers in order to find the actual value of the number of transfer units, if the values of inlet water temperature or inlet air wet bulb temperature are changed. Also an empirical correlation was conducted to obtain the required number of transfer units of the tower in hot water operation. Another correlation was found to obtain the effectiveness in the wet bulb operation.

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