Aerodynamic Design of Cooling Tower Drift Eliminators

1976 ◽  
Vol 98 (4) ◽  
pp. 450-456
Author(s):  
S. C. Yao ◽  
V. E. Schrock
Keyword(s):  
Optimum Design ◽  
Cooling Tower ◽  
Cooling System ◽  
Minimum Cost ◽  
Design Approach ◽  
Cooling Towers ◽  
Aerodynamic Design ◽  
Drift Spectrum ◽  
Air Speed

The characteristics of inertial drift eliminators of wet cooling towers are studied parametrically for their blade shapes, orientation with respect to gravity, solidity ratios, blade sizes, approaching air speed, and drift spectrum. The fundamental behavior of drift eliminators is revealed by nondimensional parameters. A method for the optimum design of an eliminator considering minimum cost versus performance is developed. This methodology can be integrated into the optimum design of the whole cooling system. An example is shown for this design approach. Suggestions on the design to improve the drainage of the collected water are given.

Retrofitting Cooling Towers: Estimates Required to Achieve the Next Level of CWA 316(b) Compliance

2004 ◽  
Author(s):  
J. M. Burns ◽  
D. C. Burns ◽  
J. S. Burns
Keyword(s):  
Environmental Impacts ◽  
Cooling Tower ◽  
Cooling System ◽  
Accurate Estimate ◽  
Environmental Benefits ◽  
Cooling Towers ◽  
Site Specific ◽  
Circulating Water ◽  
The Cost ◽  
Water Piping

Section 316(b) of the Clean Water Act regulates the potential environmental impacts of cooling water intakes in order to mitigate the adverse entrainment and impingement effects on aquatic organisms. The recently proposed EPA regulations require that power plants currently using once-through cooling systems at the very minimum, evaluate the cost and environmental benefits of retrofitting to wet or dry cooling towers for their next permit application. However, a sound cooling tower retrofit assessment cannot be confined to cooling tower issues alone. Cooling tower backfits significantly affect the entire cooling system and generating capacity. Though the industry still awaits the EPA’s February 2004 final action ruling to clarify the regulations for existing plants, it is clear that acceptable methods of plant compliance with 316(b) regulations will be decided based upon the costs of new technology available, including cooling tower retrofits. A plant not able to meet the tight impingement and entrainment reduction percentages required under 316(b) will be required to consider the cost of retrofitting technologies versus the expected environmental benefit. The EPA has complied standard costs for retrofitting cooling towers that are extremely optimistic and limited in their scope, and thus tend to be far lower than a plant would actually accrue during a retrofit. These EPA costs of compliance are accepted by default in the cost-benefit analysis unless a plant can make a compelling case that their site-specific costs are much higher than EPA’s estimate or are wholly disproportionate to the environmental benefits accrued by such a retrofit. In either case, an overly simplistic and non-comprehensive tower retrofit cost estimate will increase the chances of a plant being required to implement a closed-cooling system retrofit, which in nearly all cases is the most costly and difficult alternative. In addition to constructing a tower, a cooling tower retrofit also alters many parts of the existing cooling system. Typically, a once-through condenser is designed to operate in a siphon circuit using low pressure buried piping under the turbine building. The condenser, along with its piping, would likely have to be modified to be compatible for a conversion to a higher pressure closed-loop system. The retrofit would require installation of new circulating water pumps to provide the additional required head. Portions of the plant’s large diameter circulating water piping systems and intakes must be decommissioned or redesigned to accommodate the retrofit. The critical parts of any retrofit evaluation will be to identify the site-specific modifications required for a conversion with a reasonably accurate estimate of capital costs. An accurate retrofit evaluation must reflect the impacts on all of the circulating water system components along with the adjusted overall performance. Obtaining accurate cost data on the full scope of a retrofit project is difficult due to many factors. There have been only a handful of cooling tower retrofits in the U.S. The experiences from these are mostly inapplicable due to either their small size or unique factors that facilitated the cooling system conversion. The site-specific nature of each retrofit, including the interpretation of a matrix of environmental siting issues, makes cooling system retrofit estimates very complex. Developing an accurate estimate requires a thorough review the existing cooling system design equipment, features & layout. These data are best obtained from a site visit and interviews with key system and operations personnel. Retrofit budgets for this evaluation should not be based on very “generic” cases prepared without regard to site-specific design & operating limitations. Instead, a realistic turnkey retrofit budget is based on a well planned project that confronts the broad scope of a retrofit including the range of site-specific factors. This paper will summarize the art of the retrofit and provide considerations to develop more reliable and meaningful closedcycle retrofit cooling system cost estimates. It will describe the critical characteristics of cooling towers, pumps, circulating water piping, and condenser modifications. It will provide recommendations to produce reasonably accurate evaluations of the seasonal and peak period (energy penalty) effects of the retrofitted cooling system on plant generation. In fact, those conversion costs and the negative effects on plant generation are the key to determining the realistic effects of a proposed retrofit. Finally, it will present the major consequences of trading-off the adverse aquatic environmental impacts with airborne ones from a retrofitted wet cooling tower.

Improving the energy efficiency of a 110 MW thermal power plant by low-cost modification of the cooling system

2018 ◽  
Vol 29 (2) ◽  
pp. 245-259 ◽  
Author(s):  
Milica Jović ◽  
Mirjana Laković ◽  
Miloš Banjac
Keyword(s):  
Energy Efficiency ◽  
Power Plant ◽  
Cooling Tower ◽  
Cooling System ◽  
Thermal Power ◽  
Ambient Air ◽  
Electric Power System ◽  
Operating Conditions ◽  
Cooling Towers ◽  
Tower System

The electric power system of the Republic of Serbia relies mostly on lignite-fired thermal power plants, with 70% of the total electricity generation. Most of these plants are over 30 years old, and investment in their modernization is necessary. The energy efficiency of the 110 MW coal-fired power plant in which the condenser is cooled by the mechanical draught wet cooling towers system is analyzed in this paper. Attention is primarily devoted to operating conditions of the cold end of the plant, i.e. to the interrelationship of the condenser and cooling towers. Most important parameters that affect the operation of the cooling towers system are ambient air temperature and relative humidity, specific mass flow rate, and temperature of cooled water. With the existing cooling system, the overall energy efficiency of the plant is low, especially in the summer months, even less than 30%, due to adverse weather conditions. By upgrading existing cooling tower system by adaptation of two additional cooling tower cells, overall energy efficiency can be increased by 1.5%. The cooling tower system rehabilitation investments payback period is estimated to be less than one year. Static method for economic and financial assessment is used.

scholarly journals Heat and mass transfer performance and exergy performance evaluation of seawater cooling tower considering different inlet parameters

2021 ◽  
pp. 312-312
Author(s):  
Yang Yu ◽  
Xiaoni Qi ◽  
Xiaochen Hou ◽  
Xiaohang Qu ◽  
Qianjian Guo ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Thermal Efficiency ◽  
Cooling Tower ◽  
Exergy Efficiency ◽  
Optimum Operating ◽  
Transfer Performance ◽  
Cooling Towers ◽  
Air Speed ◽  
Exergy Performance

Cooling towers are important components within recirculating cooling water systems. Due to a shortage of freshwater resources, seawater cooling towers are widely used both in manufacturing and everyday life. This paper researches the mechanical draft counterflow wet seawater cooling tower (MDCWSCT), and establishes and verifies a detailed thermal performance calculation model. Referring to the second law of thermodynamics, the heat and mass transfer performance and exergy performance of the seawater cooling tower were studied. The effects of salinity, inlet air speed, and air wet-bulb temperature on the cooling efficiency, thermal efficiency, and exergy efficiency were analyzed. The results show that compared to the air wet-bulb temperature, changes in air speed have more influence on cooling and thermal efficiency under the study conditions. Moreover, the air wet-bulb temperature is the significant parameter affecting exergy efficiency. With an increase in salinity, the cooling, thermal, and exergy efficiency are about 2.40-8.25 %, 1.06-3.09 %, and 2.47-7.73 % lower than that of freshwater, respectively, within an air speed of 3.1-3.6 m/s. With an increase in salinity, the cooling, thermal, and exergy efficiency are about 2.28-8.47 %, 1.03-3.37 %, and 2.44-7.99 % lower than that of freshwater, respectively, within an air wet-bulb temperature of 25-27 ?. Through the exergy analysis of the seawater cooling tower, it is obvious that the heat and mass transfer performance and exergy performance can be improved by selecting the optimum operating conditions and appropriate packing specifications.

scholarly journals Study of Reserved Strength Capacity of Concrete Shell

2019 ◽  
pp. 230-237
Author(s):  
Shubham Rathi ◽  
S. S. Angalekar
Keyword(s):  
Cooling Tower ◽  
Cooling System ◽  
Shell Element ◽  
Wind Pressure ◽  
Cooling Towers ◽  
Large Space ◽  
Solid Element ◽  
Strength Capacity ◽  
Concrete Shell ◽  
Wind Pressures

Hyperbolic cooling towers have become the design standard for all natural-draft cooling towers because of their structural strength and minimum usage of material. The hyperbolic shape is particularly suited to cooling tower construction as the wide base provides a large space for the water and cooling system. As the tower widens out at the top, it supports the turbulent mixing as the heated air makes contact with the atmospheric air. Hyperbolic cooling tower is a tall structure with shells subjected to dead load and wind load. In absence of ground motion, wind becomes the major factor. In this study, 2 major models are studied with I and V column support. Each model is further divided into 2 models, i.e. one with SHELL element and another with SOLID element. All models were modelled and analyzed in ANSYS. The wind loads on these cooling tower have been calculated in the form of pressure by using the circumferentially distributed design wind pressure coefficients as given in IS: 11504 - 1985 code along with the design wind pressures at different levels as per IS: 875 (Part 3) - 1987 code. The analysis has been carried out using 8 noded shell element (SHELL281), 8 noded solid element (SOLID185) and 20 noded solid element (SOLID 186).

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.

Experimental and Theoretical Studies on Performance of GSHP Combined with Free Cooling System

2013 ◽  
Vol 368-370 ◽  
pp. 1232-1236
Author(s):  
Wei Xue Cao ◽  
Ru Chang ◽  
Can Zhang ◽  
Qiu Li Zhang
Keyword(s):  
Cooling Tower ◽  
Cooling System ◽  
Meteorological Parameter ◽  
Economic Benefits ◽  
Ground Source Heat Pump ◽  
Combined System ◽  
Climate Zones ◽  
Ground Source ◽  
Free Cooling ◽  
Experimental And Theoretical Studies

Ground-Source Heat Pump systems and tower cooling system have been studied in this paper individually by experiment and simulation using TRNSYS, the influencing factors such as meteorological parameter, cooling tower and subunit construction was analyzed. Results show that the combined system has ability to meet the cooling requirements in II building climate zones, the combined system will have energy-saving and obvious economic benefits by working through the year.

Sign in / Sign up

Export Citation Format

Share Document