Latest developments in the field of cooling towers and heat exchangers – Selected papers from the 17th IAHR international conference on cooling tower and heat exchanger, 7–11 September 2015, Gold Coast, Queensland, Australia

2016 ◽  
Vol 105 ◽  
pp. 951-952 ◽  
Author(s):  
Pradeep Bansal ◽  
Kamel Hoonan
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Gold Coast ◽  
Cooling Towers ◽  
International Conference

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 Large Dry Cooling Towers With Power-Law Heat Exchanger Performance

1976 ◽  
Vol 98 (3) ◽  
pp. 345-352 ◽  
Author(s):  
F. K. Moore ◽  
C. C. Ndubizu
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ambient Pressure ◽  
Tube Length ◽  
Cooling Towers ◽  
Tube Size ◽  
Best Value ◽  
A Chain ◽  
The Cost ◽  
Dry Cooling

An analysis is presented for heat exchanger area, tower exit area, and exchanger tube length and number, for heat exchangers in large dry cooling towers, having performance parameters given by powers of Reynolds number, but otherwise under very general cooling-cycle constraints. The calculation method is illustrated for a “spine-fin” heat exchanger which, in a tube size of about 3/8 in., seems capable of achieving low tower size in a practical device. Calculations, over ranges of water pumping power, approach, ITD, number of passes, tube size, tower shape (natural draft) or fan power (mechanical draft), and ambient pressure altitude are shown to be well represented by a chain of powers of these variables, and certain functions of the ratio of real to ideal tower exit area. This ratio is shown to have a best value, depending on the cost coefficients of heat exchange and exit areas, and it is pointed out that typical cost proportions lead to a fluid-mechanical “packaging” problem for the shallow heat exchangers which would be preferred.

scholarly journals Investigation on the Optimum Design of Heat Exchangers in a Hybrid Closed Circuit Cooling Tower

1970 ◽  
Vol 37 ◽  
pp. 52-57
Author(s):  
MMA Sarker
Keyword(s):  
Heat Exchanger ◽  
Optimum Design ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Cooling Capacity ◽  
Closed Circuit ◽  
Design Parameters ◽  
Air Inlet ◽  
Staggered Arrangement ◽  
Temperature And Pressure

Investigation on the optimum design of a heat exchanger in a Hybrid Closed Circuit Cooling Tower having a rated capacity of 1RT is performed experimentally. The heat exchanger of dimension 0.4mx0.33mx0.572m has 15x7 bare type 15.88mm OD copper coils in staggered arrangement. The relevant design parameters were selected based on the typical East Asian meteorological constrains for the year-round smooth operation of the cooling tower. This study presents results related to the cooling capacity and the cooling efficiency with respect to wet bulb temperature and pressure drop with respect to air inlet velocity. Results are also presented in terms of number of transfer units (NTU). Cooling capacity was found to be close to the rated one for the wet mode but low in dry mode operation. Keywords: Hybrid closed circuit cooling tower, Cooling capacity, Wet mode, Dry modedoi:10.3329/jme.v37i0.820Journal of Mechanical Engineering Vol.37 June 2007, pp.52-77

scholarly journals An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower

2014 ◽  
Vol 18 (3) ◽  
pp. 863-874 ◽  
Author(s):  
Xueping Du ◽  
Yantao Yin ◽  
Min Zeng ◽  
Pengqing Yu ◽  
Qiuwang Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Finned Tube ◽  
Air Cooling ◽  
Flat Tube ◽  
Tube Heat Exchanger ◽  
Air Inlet ◽  
Oval Tube

A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90?, 60 ?, 45?, and 30?) are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90?) has the worst performance while 45? and 30? has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60?, while the best performance occurred at 45? and 90? at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

Details Study of Ambient Wind Effect on Heat Dissipation Capacity of Thermal-Powerplant Dry Cooling-Towers

2014 ◽  
Author(s):  
Masoud Darbandi ◽  
Ali Behrouzifar ◽  
Ahmad Mirhashemi ◽  
Hossein Salemkar ◽  
Gerry E. Schneider
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Dissipation ◽  
Cooling Tower ◽  
Wind Effect ◽  
Circulating Water ◽  
Wind Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
Dry Cooling Tower ◽  
Dry Cooling

Thermal powerplants report a reduction in their dry cooling tower performances due to surrounding wind drafts. Therefore, it is very important to consider the influence of wind velocity in cooling tower design; especially in geographical points with high wind conditions. In this regard, we use the computational fluid dynamics (CFD) tool and simulate a dry cooling tower in different wind velocities of 0, 5 and 10 m/s. To extend our calculations; we also consider the temperature variation of circulating water through the tower heat exchanger or deltas one-by-one. We show that some heat exchangers around the tower cannot reduce the circulating water temperature sufficiently. This causes an increase in the mean temperature of those heat exchangers. The worst performances can be attributed to heat exchanger located on side wind places. We will discuss the detail performance of each delta and their assembly in draft wind conditions. This study suggests some effective ways to overcome thermal-performance of cooling tower in wind conditions.

scholarly journals Reduction of Biofilm Formation on Cooling Tower Heat Exchangers using Nano-silica Coating : Environmentally sustainable antifouling coating demonstrated on stainless steel heat exchanger tubes

2020 ◽  
Vol 64 (4) ◽  
pp. 419-424
Author(s):  
Irfan Turetgen
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Biofilm Formation ◽  
Epifluorescence Microscopy ◽  
Total Biomass ◽  
Cooling Towers ◽  
Nano Silica ◽  
Coated Surfaces ◽  
Control Surfaces ◽  
Steel Heat

Cooling towers are industrial cooling units operating to dissipate heat. As with any surface in contact with aqueous systems, biofilm formation appears on the surface of heat exchangers. Although biofilm formation on plastic tower fill in wet cooling towers has been studied widely, no studies were found regarding biofilm formation on steel heat exchangers in closed-loop systems. In this study, heat exchangers were coated with nano-silica, which is known to reduce the formation of biofilm. Natural biofilm formation was monitored for six months. Biofouling was examined monthly using epifluorescence microscopy by assessing the numbers of live and dead bacteria. It was observed that the biofilm layer formed on the nano-silica coated heat exchanger surfaces was significantly lower than on the control surfaces. 3 log microbial reduction was recorded on coated surfaces in the first month. After six months, total biomass on control surfaces reached 1.28 × 1012 cell cm−2, while the biomass on nano-silica coated surfaces was 6.3 × 104 cell cm−2.

Analysis of Heat Transfer Surface Geometries for Dry Cooling Tower Applications

1980 ◽  
Vol 102 (4) ◽  
pp. 807-812 ◽  
Author(s):  
Ali Montakhab
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Heat Transfer Surface ◽  
Per Se ◽  
Fin Tube ◽  
Dry Cooling Tower ◽  
Heat Exchanger Surface ◽  
Dry Cooling

An analysis of heat exchanger surface geometries for the purpose of reducing dry cooling tower cost is presented. Two sets of results are derived. The first set can be used to evaluate heat transfer surface geometries in an attempt to select those most suitable for dry cooling tower applications. The second set of results can be used to direct research and development efforts toward developing better geometries for dry cooling tower applications. The first set of results is general and is applicable to all heat exchanger surface geometries. The second set is valid only for helical round or continuous fins having smooth, serrated, or cut fins and for staggered and in-line tube arrangements. The methods developed in this paper are not restricted to dry cooling towers per se, but are valid for other applications of fin tube heat exchangers as well.

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.

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