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1

Ozonation of cooling tower waters  

Science.gov (United States)

Continuous ozone injection into water circulating between a cooling tower and heat exchanger with heavy scale deposits inhibits formation of further deposits, promotes flaking of existing deposits, inhibits chemical corrosion and controls algae and bacteria.

Humphrey, M. F.; French, K. R.; Howe, R. D. (inventors)

1979-01-01

2

Asbestos in cooling-tower waters  

Energy Technology Data Exchange (ETDEWEB)

Fill material in natural- or mechanical-draft cooling towers can be manufactured from a variety of materials, including asbestos cement or asbestos paper. To aid in the environmental impact assessment of cooling towers containing these asbestos types of fill, information on these materials was obtained from cooling-tower vendors and users. Samples of makeup, basin, and blowdown waters at a number of operating cooling towers were obtained, and identification and enumeration of asbestos in the samples were performed by transmission electron microscopy, selected-area electron diffraction, and energy-dispersive x-ray analysis. Asbestos fibers were detected in cooling-tower water at 10 of the 18 sites sampled in the study. At all but three sites, the fibers were detected in cooling-tower basin or blowdown samples, with no fibers detected in the makeup water. The fibers were identified as chrysotile at all sites except one. Concentrations were on the order of 10/sup 6/ to 10/sup 8/ fibers/liter of water, with mass concentrations between <0.1 ..mu..g/liter to 37 ..mu..g/liter. The maximum concentrations of asbestos fibers in air near ground due to drift from cooling towers were estimated (using models) to be on the order of asbestos concentrations reported for ambient air up to distances of 4 km downwind of the towers. The human health hazard due to abestos in drinking-water supplies is not clear. Based on current information, the concentrations of asbestos in natural waters after mixing with cooling-tower blowdown containing 10/sup 6/ to 10/sup 8/ fibers/liter will pose little health risk. These conclusions may need to be revised if future epidemiological studies so indicate.

Lewis, B.A.G.

1977-12-01

3

Mycobacteria in Finnish cooling tower waters.  

Science.gov (United States)

Evaporative cooling towers are water systems used in, e.g., industry and telecommunication to remove excess heat by evaporation of water. Temperatures of cooling waters are usually optimal for mesophilic microbial growth and cooling towers may liberate massive amounts of bacterial aerosols. Outbreaks of legionellosis associated with cooling towers have been known since the 1980's, but occurrences of other potentially pathogenic bacteria in cooling waters are mostly unknown. We examined the occurrence of mycobacteria, which are common bacteria in different water systems and may cause pulmonary and other soft tissue infections, in cooling waters containing different numbers of legionellae. Mycobacteria were isolated from all twelve cooling systems and from 92% of the 24 samples studied. Their numbers in the positive samples varied from 10 to 7.3 × 10(4) cfu/L. The isolated species included M. chelonae/abscessus, M. fortuitum, M. mucogenicum, M. peregrinum, M. intracellulare, M. lentiflavum, M. avium/nebraskense/scrofulaceum and many non-pathogenic species. The numbers of mycobacteria correlated negatively with the numbers of legionellae and the concentration of copper. The results show that cooling towers are suitable environments for potentially pathogenic mycobacteria. Further transmission of mycobacteria from the towers to the environment needs examination. PMID:23937212

Torvinen, Eila; Suomalainen, Sini; Paulin, Lars; Kusnetsov, Jaana

2014-04-01

4

Cooling tower water conditioning study. [using ozone  

Science.gov (United States)

Successful elimination of cooling tower treatment chemicals was demonstrated. Three towers functioned for long periods of time with ozone as the only treatment for the water. The water in the systems was reused as much as 30 times (cycles of concentration) without deleterious effects to the heat exchangers. Actual system blow-down was eliminated and the only makeup water added was that required to replace the evaporation and mist entrainment losses. Minimum water savings alone are approximately 75.1 1/kg/year. Cost estimates indicate that a savings of 55 percent was obtained on the systems using ozone. A major problem experienced in the use of ozone for cooling tower applications was the difficulty of accurate concentration measurements. The ability to control the operational characteristics relies on easily and accurately determined concentration levels. Present methods of detection are subject to inaccuracies because of interfering materials and the rapid destruction of the ozone.

Humphrey, M. F.; French, K. R.

1979-01-01

5

Cooling tower water circuits with raceways  

International Nuclear Information System (INIS)

Two physical models built at the National Hydraulics Laboratory in Chatou have led to the determination of the design of the works. This new design economizes 4 to 5 MW on pumping power for each cooling tower

6

Isolation of Legionella pneumophilia from cooling tower water by filtration.  

Science.gov (United States)

Methods are described for detection of Legionella pneumophila in cooling tower water or other water sources by direct fluorescent-antibody staining. A procedure for isolation of Legionella bacteria from water samples by guinea pig inoculation is described. Two different serogroups of L. pneumophila were isolated repeatedly from one of the cooling towers. PMID:7020594

Orrison, L H; Cherry, W B; Milan, D

1981-05-01

7

Isolation of Legionella pneumophila from Cooling Tower Water by Filtration  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Methods are described for detection of Legionella pneumophila in cooling tower water or other water sources by direct fluorescent-antibody staining. A procedure for isolation of Legionella bacteria from water samples by guinea pig inoculation is described. Two different serogroups of L. pneumophila were isolated repeatedly from one of the cooling towers.

Orrison, Leta H.; Cherry, William B.; Milan, David

1981-01-01

8

Cooling towers  

International Nuclear Information System (INIS)

What is the effect of 0.6C (1F) temperature rise across turbines, compressors, or evaporators? Enthalpy charts indicate for every 0.6C (1F) hotter water off the cooling tower will require an additional 2 1/2% more energy cost. Therefore, running 2.2C (4F) warmer due to substandard cooling towers could result in a 10% penalty for overcoming high heads and temperatures. If it costs $1,250,000.00 a year to operate the system, $125,000.00 is the energy penalty for hotter water. This paper investigates extra fuel costs involved in maintaining design electric production with cooling water 0.6C (1F) to 3C (5.5F) hotter than design. If design KWH cannot be maintained, paper will calculate dollar loss of saleable electricity. The presentation will conclude with examining the main causes of deficient cold water production. State-of-the-art upgrading and methodology available to retrofit existing cooling towers to optimize lower cooling water temperatures will be discussed

9

Use of nanofiltration to reduce cooling tower water consumption.  

Energy Technology Data Exchange (ETDEWEB)

Nanofiltration (NF) can effectively treat cooling-tower water to reduce water consumption and maximize water usage efficiency of thermoelectric power plants. A pilot is being run to verify theoretical calculations. A side stream of water from a 900 gpm cooling tower is being treated by NF with the permeate returning to the cooling tower and the concentrate being discharged. The membrane efficiency is as high as over 50%. Salt rejection ranges from 77-97% with higher rejection for divalent ions. The pilot has demonstrated a reduction of makeup water of almost 20% and a reduction of discharge of over 50%.

Altman, Susan Jeanne; Ciferno, Jared

2010-10-01

10

Use of nanofiltration to reduce cooling tower water usage.  

Energy Technology Data Exchange (ETDEWEB)

Nanofiltration (NF) can effectively treat cooling-tower water to reduce water consumption and maximize water usage efficiency of thermoelectric power plants. A pilot is being run to verify theoretical calculations. A side stream of water from a 900 gpm cooling tower is being treated by NF with the permeate returning to the cooling tower and the concentrate being discharged. The membrane efficiency is as high as over 50%. Salt rejection ranges from 77-97% with higher rejection for divalent ions. The pilot has demonstrated a reduction of makeup water of almost 20% and a reduction of discharge of over 50%.

Sanchez, Andres L.; Everett, Randy L.; Jensen, Richard Pearson; Cappelle, Malynda A.; Altman, Susan Jeanne

2010-09-01

11

Asbestos in cooling-tower waters. Final report  

International Nuclear Information System (INIS)

Water discharges from cooling towers constructed with asbestos fill were found to contain chrysotile--asbestos fibers at concentrations as high as 108 fibers/liter. The major source of these fibers, appears to be the components of the towers rather than the air drawn through the towers or the makeup water taken into the towers. Suggested mechanisms for the release of chrysotile fibers from cooling-tower fill include freeze-thaw cycles and dissolution of the cement due to acidic components of the circulating water. Ash- or other material-settling ponds were found to reduce asbestos-fiber concentrations in cooling-tower effluent. The literature reviewed did not support the case for a causal relationship between adverse human health effects and drinking water containing on the order of 106 chrysotile--asbestos fibers/liter; for this and other reasons, it is not presently suggested that the use of asbestos fill be discontinued. However, caution and surveillance are dictated by the uncertainties in the epidemiological studies, the absence of evidence for a safe threshold concentration in water, and the conclusive evidence for adverse effects from occupational exposure. It is recommended that monitoring programs be carried out at sites where asbestos fill is used; data from such programs can be used to determine whether any mitigative measures should be taken. On the basis of estimates made in this study, monitoring for asbestos in drift from cooling toring for asbestos in drift from cooling towers does not appear to be warranted

12

A descaling treatment for aerated water, especially in cooling towers  

International Nuclear Information System (INIS)

Carbon dioxide is injected into the water aerating air, for example in the water flowing in a cooling tower; the dissolved carbon dioxide prevents scaling to take place on the heat exchange surfaces or leads to the dissolution of the deposited scale. This system has the advantage to avoid any acid use and thus polluting effluents

13

Performance of water distribution systems in a pilot cooling tower  

International Nuclear Information System (INIS)

An experimental study has been carried out on the water distribution system of a Pilot cooling tower of 160 m3/hr The performances of different industrial water distributors have been evaluated by changing the operative conditions of the pilot tower. In particular, the efficiency and the uniformity of the water distribution have been investigated and compared with the results obtained in a small-scale loop, in which the single nozzles were tested. Measurements in both systems, pilot tower and small scale loop, included the geometric characteristics of the jet umbrella by ensemble photography, the wetted zone by measuring the specific flowrate, the drop-size distribution and liquid concentration by high-speed photography. The results show that correlations exist between the nozzle behaviour in single and pilot tower configuration. The uniformity of water distribution in the pilot tower is strongly related to the nozzle installation pattern and to the operative conditions. Coalescence plays an important role on the drop size distribution in the pilot-tower. Comments upon the influence of these parameters on tower behaviour are also included

14

Factors Stimulating Propagation of Legionellae in Cooling Tower Water  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Our survey of cooling tower water demonstrated that the highest density of legionellae, ?104 CFU/100 ml, appeared in water containing protozoa, ?102 MPN/100 ml, and heterotrophic bacteria, ?106 CFU/100 ml, at water temperatures between 25 and 35°C. Viable counts of legionellae were detected even in the winter samples, and propagation, up to 105 CFU/100 ml, occurs in summer. The counts of legionellae correlated positively with increases in water temperature, pH, and protozoan counts, bu...

Yamamoto, Hiroyuki; Sugiura, Minoru; Kusunoki, Shinji; Ezaki, Takayuki; Ikedo, Masanari; Yabuuchi, Eiko

1992-01-01

15

Cooling tower calculations  

International Nuclear Information System (INIS)

The problems are summed up of the dynamic calculation of cooling towers with forced and natural air draft. The quantities and relations are given characterizing the simultaneous exchange of momentum, heat and mass in evaporative water cooling by atmospheric air in the packings of cooling towers. The method of solution is clarified in the calculation of evaporation criteria and thermal characteristics of countercurrent and cross current cooling systems. The procedure is demonstrated of the calculation of cooling towers, and correction curves and the effect assessed of the operating mode at constant air number or constant outlet air volume flow on their course in ventilator cooling towers. In cooling towers with the natural air draft the flow unevenness is assessed of water and air relative to its effect on the resulting cooling efficiency of the towers. The calculation is demonstrated of thermal and resistance response curves and cooling curves of hydraulically unevenly loaded towers owing to the water flow rate parameter graded radially by 20% along the cross-section of the packing. Flow rate unevenness of air due to wind impact on the outlet air flow from the tower significantly affects the temperatures of cooled water in natural air draft cooling towers of a design with lower demands on aerodynamics, as early as at wind velocity of 2 m.s-1 as was demonstrated on a concrete example. (author). 11 figs., 10 refs

16

Reducing water consumption of an industrial plant cooling unit using hybrid cooling tower  

International Nuclear Information System (INIS)

Water consumption is an important problem in dry zones and poor water supply areas. For these areas use of a combination of wet and dry cooling towers (hybrid cooling) has been suggested in order to reduce water consumption. In this work, wet and dry sections of a hybrid cooling tower for the estimation of water loss was modeled. A computer code was also written to simulate such hybrid cooling tower. To test the result of this simulation, a pilot hybrid tower containing a wet tower and 12 compact air cooled heat exchangers was designed and constructed. Pilot data were compared with simulation data and a correction factor was added to the simulation. Ensuring that the simulation represents the actual data, it was applied to a real industrial case and the effect of using a dry tower on water loss reduction of this plant cooling unit was investigated. Finally feasibility study was carried out to choose the best operating conditions for the hybrid cooling tower configuration proposed for this cooling unit.

17

On hydraulics calculation of water distribution in cooling towers  

International Nuclear Information System (INIS)

A mathematical model is described for the hydraulics calculation of water distribution in the natural draught cooling towers for the Temelin nuclear power plant. The model allows determining the form of the mechanical energy curve along the asbestos cement pipe and the main distribution trough, the form of the pressure curve in the pipe and the form of the level in an open trough, the cross section velocities in the individual distribution network sections, and the flow through nozzles, i.e., the actual distribution over the tower surface of specific load due to cooling water. The values are suggested of coefficients for calculations of losses due to friction, of local losses, and of outlet coefficients obtained from the results of original studies and completed with literature data. The computer program is written in the Fortran 77 language. (Z.M.). 5 figs., 5 tabs., 9 refs

18

Engineering and economic evaluation of wet/dry cooling towers for water conservation  

International Nuclear Information System (INIS)

The results are presented of a design and cost study for wet/dry tower systems used in conjunction with 1000 MWe nuclear power plants to reject waste heat while conserving water. Design and cost information for wet/dry tower systems are presented, and these cooling system alternatives are compared with wet and dry tower systems to determine whether the wet/dry tower concept is an economically viable alternative. The wet/dry cooling tower concept investigated is one which combines physically separated wet towers and dry towers into an operational unit. In designing the wet/dry tower, a dry cooling tower is sized to carry the plant heat load at low ambient temperatures, and a separate wet tower is added to augment the heat rejection of the dry tower at higher ambient temperatures. These wet/dry towers are designed to operate with a conventional low back pressure turbine commercially available today. The component wet and dry towers are state-of-the-art designs. From this study it was concluded that: wet/dry cooling systems can be designed to provide a significant economic advantage over dry cooling yet closely matching the dry tower's ability to conserve water, a wet/dry system which saves as much as 99 percent of the make-up water required by a wet tower can maintain that economic advantage, and therefore, for power plant sites where water is in short supply, wet/dry cooling is the economic choice over dry cooling

19

Gasifier waste water treatment: Phase I cooling tower assessment  

Energy Technology Data Exchange (ETDEWEB)

Details of an advanced study of the treatability of waste waters from the fixed-bed gasification of lignite describe the test equipment and results at a pilot plant in North Dakota using stripped-gas liquor (SGL) as cooling tower makeup. Ammonia, alkalinity, phenol, and other non-hydantoin organics were removed from the cooling water by stripping and/or biological degradation, with the phenol concentration in the exhaust air exceeding the odor threshold. It will be necessary to control foaming of the circulating water, but both glycol and silicon based agents performed well during the test. It will also be necessary to reduce the high level of biofouling on heat transfer surfaces, although stainless steel fouling was not a major problem. The conclusion is that SGL is limited by potentially serious operating problems without additional treatment. 5 references, 4 figures, 7 tables.

Mann, M.D.; Willson, W.G.; Hendrikson, J.G.; Winton, S.L.

1985-02-01

20

Coagulation chemistries for silica removal from cooling tower water.  

Energy Technology Data Exchange (ETDEWEB)

The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

2010-02-01

 
 
 
 
21

Complex development of cooling towers  

International Nuclear Information System (INIS)

Development of the design of cooling towers and recirculated cooling water systems at the Industrial Design Co. (IPARTERV). Cooling technological elements, drift eliminators, water distribution systems, water spray equipments, packings. Building technology, building constructions. Reconstruction of cooling towers. Desirable future of the power economy

22

Design change of tower cooling water system for proton accelerator research center  

International Nuclear Information System (INIS)

The Tower Cooling Water System (TC) is designed to reject the heat load generated by operating the accelerators and the utility facilities through the component cooling water (CCW) heat exchangers. The circulating water discharged from the circulating water pumps passes through the CCW heat exchangers, the Chiller condenser and the air compressor, and the heated circulating water is return to the cooling tower for the heat removal. In this study, The design of Tower Cooling Water System is changed as follows : At First, The quantity of cells is changed into six in order to operate the cooling tower accurately correspond with condition of each equipment of head loads. The fans of cooling tower are controlled by the signal of TEW installed in the latter parts of it. The type of circulation water pump is modified to centrifugal pump and debris filter system is deleted

23

Numerical study of coupled heat and mass transfer in geothermal water cooling tower  

International Nuclear Information System (INIS)

Cross flow mechanical cooling towers, widely spreads all over the south region of Tunisia are used for cooling geothermal water for agriculture and domestic ends. These towers are sized empirically and present several problems in regard to operation and electrical energy consumption. This work aims to study the thermal behaviour of this type of cooling towers through a developed mathematical model considering the variation of the water mass flow rate inside the tower. The analysis of the water and air temperatures distribution along the cooling tower had underlined the negative convection phenomenon at a certain height of the tower. This analysis has shown also that the difference in water temperature between the inlet and the outlet of the tower is much higher than the one of air due to the dominance of the evaporative potential compared to the convective one. In addition, the variations of the air humidity along the cooling tower and the quantity of evaporated water have been investigated. The loss of water by evaporation is found to be 5.1% of the total quantity of water feeding the cooling tower. Interesting future prospects are expected for validation of the developed model to optimize the operating of the cooling tower

24

Engineering and economic evaluation of wet/dry cooling towers for water conservation  

Energy Technology Data Exchange (ETDEWEB)

The results are presented of a design and cost study for wet/dry tower systems used in conjunction with 1000 MWe nuclear power plants to reject waste heat while conserving water. Design and cost information for wet/dry tower systems are presented, and these cooling system alternatives are compared with wet and dry tower systems to determine whether the wet/dry tower concept is an economically viable alternative. The wet/dry cooling tower concept investigated is one which combines physically separated wet towers and dry towers into an operational unit. In designing the wet/dry tower, a dry cooling tower is sized to carry the plant heat load at low ambient temperatures, and a separate wet tower is added to augment the heat rejection of the dry tower at higher ambient temperatures. These wet/dry towers are designed to operate with a conventional low back pressure turbine commercially available today. The component wet and dry towers are state-of-the-art designs. From this study it was concluded that: wet/dry cooling systems can be designed to provide a significant economic advantage over dry cooling yet closely matching the dry tower's ability to conserve water, a wet/dry system which saves as much as 99 percent of the make-up water required by a wet tower can maintain that economic advantage, and therefore, for power plant sites where water is in short supply, wet/dry cooling is the economic choice over dry cooling.

Hu, M.C.

1976-11-01

25

The efficiency index of mechanical-draft and chimney-type water cooling towers operation  

Science.gov (United States)

It is shown that the water temperature ranges in cooling towers given in the regulatory documents are not consistent with the standardized heat loads. It is also demonstrated that the existing criteria for estimating the effect from retrofitting of cooling towers are far from being perfect. The notions of cooling tower efficiency index and their operating characteristics with the nominal values of the main parameters are introduced. A procedure for determining these quantities is developed. An algorithm for directly calculating the economic effect from reconstruction of cooling towers is proposed.

Sosnovskii, S. K.; Kravchenko, V. P.

2014-09-01

26

Ecological impact of chloro-organics produced by chlorination of cooling tower waters  

International Nuclear Information System (INIS)

Experimental results of the initial assessment of chlorine-containing compounds in the blowdown from cooling towers and the possible mutagenic activity of these compounds are reported. High-resolution liquid chromatographic separations were made on concentrates of the blowdown from the cooling tower at the High Flux Isotope Reactor (HFIR) and from the recirculating water system for the cooling towers at the Oak Ridge Gaseous Diffusion Plant (ORGDP), Oak Ridge, Tennessee. The chromatograms of chlorinated cooling waters contained numerous uv-absorbing and cerate-oxidizable constituents that are now being processed through a multicomponent identification procedure. Concentrates of the chlorinated waters are also being examined for mutagenic activity

27

Legionella oakridgensis: unusual new species isolated from cooling tower water.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe a new species of Legionella represented by 10 strains isolated from industrial cooling towers. Legionella oakridgensis differed genetically from the other seven species of Legionella in DNA hybridization studies and differed serologically in direct fluorescent-antibody tests. The new species, unlike all other species except L. jordanis, did not require added L-cysteine for growth in serial transfer on charcoal-yeast extract agar. L. oakridgensis, as well as three other species tes...

Orrison, L. H.; Cherry, W. B.; Tyndall, R. L.; Fliermans, C. B.; Gough, S. B.; Lambert, M. A.; Mcdougal, L. K.; Bibb, W. F.; Brenner, D. J.

1983-01-01

28

Legionella adelaidensis, a new species isolated from cooling tower water.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A Legionella-like organism (strain 1762-AUS-E) was isolated from a cooling tower of an air-conditioning system in Adelaide, South Australia, Australia. The isolate was presumptively identified as a Legionella strain by its growth requirement for L-cysteine and its cellular branched-chain fatty acids. Strain 1762-AUS-E was serologically distinct in the slide agglutination test with absorbed antisera. DNA hybridization confirmed that it is a new Legionella species for which the name Legionella ...

Benson, R. F.; Thacker, W. L.; Lanser, J. A.; Sangster, N.; Mayberry, W. R.; Brenner, D. J.

1991-01-01

29

Simultaneous effects of water spray and crosswind on performance of natural draft dry cooling tower  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To investigate the effect of water spray and crosswind on the effectiveness of the natural draft dry cooling tower (NDDCT), a three-dimensional model has been developed. Efficiency of NDDCT is improved by water spray system at the cooling tower entrance for high ambient temperature condition with and without crosswind. The natural and forced heat convection flow inside and around the NDDCT is simulated numerically by solving the full Navier-Stokes equations in both air and water droplet...

Ahmadikia Hossein; Soleimani Mohsen; Gholami Ehsan

2013-01-01

30

Detection of Legionella spp. in cooling tower water by the polymerase chain reaction method.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The presence of Legionella spp. in cooling tower water was investigated by using the polymerase chain reaction. Total Legionella spp. detection was performed with 20-mer 5S rRNA complementary DNA sequence primers, and specific Legionella pneumophila detection was performed with 20-mer and then 21-mer macrophage infectivity potentiator gene sequence primers. Of 27 cooling tower water samples, 25 were positive for Legionella spp., and 14 of these contained L. pneumophila.

Koide, M.; Saito, A.; Kusano, N.; Higa, F.

1993-01-01

31

Cooling tower wood deterioration by fungi in the service water system of a test reactor  

International Nuclear Information System (INIS)

Wood deterioration in wet cooling towers is a universal industrial problem. Wood deterioration in the cooling tower has been a problem in the cooling water circuit of a Fast Breeder Test Reactor at Kalpakkam which uses an open recirculation cooling system. Studies on the fungal flora and water quality of the service and source water were carried out to examine the factors responsible for wood deterioration. Data on weight loss following exposures to different fungal species showed that deterioration was more pronounced in the case of aspergillus niger (14%), as compared to others: Penicillium citrinum (11%), pacilomyces sp. (10%) trichoderma viride (8%), aspergillus flavus (9%), A. terreus (11%), and control (6%). (author)

32

Optimization of dry cooling towers for circulating water indirect cooling in the thermal power plants  

International Nuclear Information System (INIS)

A mathematical model is presented to design dry cooling tower systems and to evaluate their off-design performances. The influence of the more important thermal, hydraulic and geometric parameters on the tower is shown. A preliminary 'optimum' is predicted by means of a computer code. Moreover the influence of the designed cooling system on the performance of thermal power plants is analysed

33

Simultaneous effects of water spray and crosswind on performance of natural draft dry cooling tower  

Directory of Open Access Journals (Sweden)

Full Text Available To investigate the effect of water spray and crosswind on the effectiveness of the natural draft dry cooling tower (NDDCT, a three-dimensional model has been developed. Efficiency of NDDCT is improved by water spray system at the cooling tower entrance for high ambient temperature condition with and without crosswind. The natural and forced heat convection flow inside and around the NDDCT is simulated numerically by solving the full Navier-Stokes equations in both air and water droplet phases. Comparison of the numerical results with one-dimensional analytical model and the experimental data illustrates a well-predicted heat transfer rate in the cooling tower. Applying water spray system on the cooling tower radiators enhances the cooling tower efficiency at both no wind and windy conditions. For all values of water spraying rate, NDDCTs operate most effectively at the crosswind velocity of 3m/s and as the wind speed continues to rise to more than 3 m/s up to 12 m/s, the tower efficiency will decrease by approximately 18%, based on no-wind condition. The heat transfer rate of radiator at wind velocity 10 m/s is 11.5% lower than that of the no wind condition. This value is 7.5% for water spray rate of 50kg/s.

Ahmadikia Hossein

2013-01-01

34

Distinct difference of flaA genotypes of Legionella pneumophila between isolates from bath water and cooling tower water.  

Science.gov (United States)

To investigate the genetic difference of Legionella pneumophila in human-made environments, we collected isolates of L. pneumophila from bath water (n = 167) and cooling tower water (n = 128) primarily in the Kanto region in 2001 and 2005. The environmental isolates were serogrouped and sequenced for a target region of flaA. A total of 14 types of flaA genotypes were found: 10 from cooling tower water and nine from bath water. The flaA genotypes of isolates from cooling tower water were quite different from those of bath water. PMID:19039955

Amemura-Maekawa, Junko; Kura, Fumiaki; Chang, Bin; Suzuki-Hashimoto, Atsuko; Ichinose, Masayuki; Endo, Takuro; Watanabe, Haruo

2008-09-01

35

Cooling-water pumps in cooling circuits with wet cooling tower  

International Nuclear Information System (INIS)

The nature of recooling operation influences the delivery head of the cooling-water pumps and their control. According to the cooling-water flow and delivery heads different pump designs are provided. The author describes a number of control alternatives and also gives a survey of the pump designs and the possibilities of their construction and location. (orig.)

36

Water vapour rises from the cooling towers for the ATLAS detector at Point 1  

CERN Multimedia

Electronics on the ATLAS detector produce heat when the experiment is running. An elaborate cooling system keeps the detector from overheating. On the surface, the warm water vapour that rises from the detector 100metres underground is clearly visible from the ATLAS cooling towers on the CERN Meyrin site in Switzerland.

Brice, Maximilien

2015-01-01

37

Water tower  

CERN Multimedia

The water tower, being built on the highest point of the site, 460.5 m above the sea level. The tank will hold 750 m3 of water, and the tower will be topped by a knob which can serve as a geological survey reference mark.

1970-01-01

38

Evaluation Of Cooling Tower Degradation  

International Nuclear Information System (INIS)

Cooling tower degradation has been evaluated for the last 10 years. Its heat transfer capacity has been decreasing after several years of operation due to aging. Evaluation is carried out by calculating the degradation rate, namely the annual increase of outlet temperatures of the cooling tower. Data was randomly taken daily at 15 MW reactor power. Data was taken after the reactor operation of ± 8 hours. Evaluation since 1990 shows that the degradation rate is nearly one degree per year. This degradation can be by minimized, replacement of damaged components, non-excessive operation and design modification of the cooling tower namely by extending the period of contract between water and air

39

The effect the pressure drop of regular packings has on the return water evaporation cooling efficiency in cooling towers  

Science.gov (United States)

Results obtained from a qualitative analysis aimed at determining the effect the pressure drop coefficient of regular film, droplet-film, and droplet-type packings has on the efficiency of the return water cooling process in cooling towers are presented.

Pushnov, A. S.

2013-06-01

40

Negative enrichment procedure for isolation of Legionella pneumophila from seeded cooling tower water.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A negative enrichment procedure was developed which was capable of isolating Legionella pneumophila directly from seeded air-conditioning cooling tower water onto laboratory media. This procedure was based on an 8-h incubation under conditions that were bactericidal to the indigenous water microflora but merely bacteriostatic to L. pneumophila.

Thorpe, T. C.; Miller, R. D.

1980-01-01

 
 
 
 
41

Cooling tower symposium 1977  

International Nuclear Information System (INIS)

Natural draft cooling towers are structures remarkable in many ways. They are extremely large shell structures, mainly affected by the wind load. It is above all the aerodynamic effects that have to be taken into account in cooling tower design. Their construction also differs in many ways from the construction of other buildings or structures and, finally, they are an unused-to sight in the landscape. The topics dealt with in this issue correspond to the lectures presented to the KIB symposium of 1977, giving a survey of the state-of-the-art at that time of cooling tower design and construction. (orig./HP)

42

Atmospheric cooling tower with reduced plume  

International Nuclear Information System (INIS)

The cooling tower, usable in thermal-electric power plants, has a vertical chimney having a central water tower fed with water to be cooled, a pipe network distributing water coming from the water tower and dispersing it in flows streaming down on a packing, and a basin to receive the water cooled by contact with an air flow passing through apertures at the lower part of the chimney and flowing up through the chimney. The cooling tower has inlet air pipes for the said apertures to a zone of the chimney situated beyond the streaming zone, the said pipes being arranged such their surface is swept by water to be cooled

43

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water  

Science.gov (United States)

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27 000 kJ/h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 104 was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m/s), and air mass velocity (3660 kg/h m2), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

Chien, S. H.; Hsieh, M. K.; Li, H.; Monnell, J.; Dzombak, D.; Vidic, R.

2012-02-01

44

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water.  

Science.gov (United States)

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ?h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m?s), and air mass velocity (3660 kg?h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality. PMID:22380105

Chien, S H; Hsieh, M K; Li, H; Monnell, J; Dzombak, D; Vidic, R

2012-02-01

45

Legionella anisa: a new species of Legionella isolated from potable waters and a cooling tower.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Between March 1980 and June 1981, five strains of Legionella-like organisms were isolated from water. Four were recovered from potable water collected from hospitals in Chicago, Ill., and Los Angeles, Calif., during outbreaks of nosocomial legionellosis. The fifth strain was isolated from water collected from an industrial cooling tower in Jamestown, N.Y. The strains exhibited biochemical reactions typical of Legionella species and were gram-negative motile rods which grew on buffered charcoa...

Gorman, G. W.; Feeley, J. C.; Steigerwalt, A.; Edelstein, P. H.; Moss, C. W.; Brenner, D. J.

1985-01-01

46

Cooling towers: a bibliography  

International Nuclear Information System (INIS)

This bibliography cites 300 selected references containing information on various aspects of large cooling tower technology, including design, construction, operation, performance, economics, and environmental effects. The towers considered include natural-draft and mechanical-draft types employing wet, dry, or combination wet-dry cooling. A few references deal with alternative cooling methods, principally ponds or spray canals. The citations were compiled for the DOE Energy Information Data Base (EDB) covering the period January to December 1980. The references are to reports from the Department of Energy and its contractors, reports from other government or private organizations, and journal articles, books, conference papers, and monographs from US originators

47

Cooling tower make-up water processing for nuclear power plants - a comparison  

International Nuclear Information System (INIS)

In water-cooled nuclear power plants, 1 to 2% of the total investment costs go to cooling tower make-up water processing. The crude water taken from rivers or stationary waters for cooling must be sufficiently purified regarding its content of solids, carbonate hardness and corrosive components so as to guarantee an operation free of disturbances. At the same time, the processing methods must be selected for operational-economic reasons in such a manner that waste water and waste problems are kept small regarding environmental protection. The various parameters described have a decisive influence on the processing methods of the crude water, individual processes (filtration, sedimentation, decarbonization) are described, circuit possibilities for cooling water systems are compared and the various processes are analyzed and compared with regard to profitableness and environmental compatability. (RB)

48

Prediction of Air and Water Film Coefficients in Cooling Towers from Penetration Theory  

Science.gov (United States)

In the experimental analysis of cooling towers, it is not necessarily easy to obtain the values of air and water phase film volumetric coefficients, because the experimental conditions are limited to which the Mickley's graphical method is applicable. The purpose of this study is to predict the individual coefficients using more practical method based on the penetration theory for water film. The tower used in this study is of a commercial induced draft counterflow type. Water-cooling experiments were made with constantly designed air and water flow rates and with varied water temperatures. Then, we attempted to predict the individual coefficients from these over-all results by means of the reported procedure. Finally, applying our method to the similar experimental date of other workers, we obtained nearly equal results compared with the Mickley's method.

Yazaki, Yoshimu; Yoshioka, Hideaki

49

Determination of fan flow and water rate adjustment for off-design cooling tower tests  

International Nuclear Information System (INIS)

The determination of the performance of a mechanical draft cooling tower requires that the air mass flow through the tower be known. Since this flow is not measured, it has been customary to use the manufacturer's design air flow and adjust it by the one-third power of the ratio of the design to test fan horsepower. The most nearly correct approximation of air flow through a tower can be obtained by incrementally moving through the tower from air inlet to outlet while calculating mass flows, energy balances, and pressure drops for each increment and then utilizing fan curves to determine volumetric and mass flows. This procedure would account for changes in air humidity and density through the tower, evaporation of water, effect of water rate on air pressure drop, and changes in fan characteristics. These type calculations may be within the capabilities of all in the near future, but for the interim, it is recommended that a more elementary approach be used which can be handled with a good calculator and without any proprietary data. This approach depends on certain assumptions which are acceptable if the tower test is conducted within CTI code requirements. The fan must be considered a constant suction volume blower for a given blade pitch. The total pressure at the fan, a function of volumetric flow and wet air density, must be assumed to be unaffected by other considerations, and the fan horsepower must be assumed to change only as volumetric flow and wet air densi only as volumetric flow and wet air density changes. Given these assumptions, along with design information normally provided with a tower, the determination of air flow through a tower in a test can be made from CTI test data. The air flow, and consequently the water rate adjustment and corrected water to air ratio, are derived and found to be direct functions of horsepower and density and an inverse function of wet air humidities

50

Self-optimizing Control of Cooling Tower for Efficient Operation of Chilled Water Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The chilled-water systems, mainly consisting of electric chillers and cooling towers, are crucial for the ventilating and air conditioning systems in commercial buildings. Energy efficient operation of such systems is thus important for the energy saving of commercial buildings. This paper presents an extremum seeking control (ESC) scheme for energy efficient operation of the chilled-water system, and presents a Modelica based dynamic simulation model for demonstrating the effectiveness of th...

Li, Xiao; Li, Yaoyu; Seem, John E.; Li, Pengfei

2012-01-01

51

COOLING TOWER PLUME MODEL  

Science.gov (United States)

A review of recently reported cooling tower plume models yields none that is universally accepted. The entrainment and drag mechanisms and the effect of moisture on the plume trajectory are phenomena which are treated differently by various investigators. In order to better under...

52

Legionella fairfieldensis sp. nov. isolated from cooling tower waters in Australia.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Three Legionella-like organisms were isolated from water from the cooling towers of two Australian institutions. The strains grew on buffered charcoal-yeast extract (BCYE) agar but not on BCYE agar in the absence of L-cysteine. Gas-liquid chromatography profiles of the isolates were consistent with those for Legionella spp. They were serologically distinct from other legionellae in a slide agglutination test. DNA hybridization studies showed that the three isolates belong to a new species of ...

Thacker, W. L.; Benson, R. F.; Hawes, L.; Gidding, H.; Dwyer, B.; Mayberry, W. R.; Brenner, D. J.

1991-01-01

53

Genome Sequence of Legionella massiliensis, Isolated from a Cooling Tower Water Sample.  

Science.gov (United States)

We present the draft genome sequence of Legionella massiliensis strain LegA(T), recovered from a cooling tower water sample, using an amoebal coculture procedure. The strain described here is composed of 4,387,007 bp, with a G+C content of 41.19%, and its genome has 3,767 protein-coding genes and 60 predicted RNA genes. PMID:25323728

Pagnier, Isabelle; Croce, Olivier; Robert, Catherine; Raoult, Didier; La Scola, Bernard

2014-01-01

54

Extracellular polysaccharides produced by cooling water tower biofilm bacteria and their possible degradation.  

Science.gov (United States)

The extracellular polymers (EPS) of biofilm bacteria that can cause heat and mass transfer problems in cooling water towers in the petrochemical industry were investigated. In addition, these microorganisms were screened for their ability to grow and degrade their own EPS and the EPS of other species. Twelve bacteria producing the most EPS were isolated from cooling water towers and characterized biochemically by classic and commercial systems. These were species of Pseudomonas, Burkholderia, Aeromonas, Pasteurella, Pantoea, Alcaligenes and Sphingomonas. EPS of these species were obtained by propan-2-ol precipitation and centrifugation from bacterial cultures in media enriched with glucose, sucrose or galactose. EPS yields were of 1.68-4.95 g l(-1). These EPS materials were characterized for total sugar and protein contents. Their total sugar content ranged from 24 to 56% (g sugar g(-1) EPS), and their total protein content ranged from 10 to 28% (g protein g(-1) EPS). The monosaccharide compositions of EPS were determined by HPLC. Generally, these compositions were enriched in galactose and glucose, with lesser amounts of mannose, rhamnose, fructose and arabinose. All bacteria were investigated in terms of EPS degradation. Eight of the bacteria were able to utilize EPS from Burkholderia cepacia, seven of the bacteria were able to utilize EPS from Pseudomonas sp. and Sphingomonas paucimobilis. The greatest viscosity reduction of B. cepacia was obtained with Pseudomonas sp. The results show that the bacteria in this study are able to degrade EPS from biofilms in cooling towers. PMID:18256966

Ceyhan, Nur; Ozdemir, Guven

2008-01-01

55

Disinfection process study of cooling water by H2O2/UV : Application to a cooling tower  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Legionella is a major public health issue as they are responsible for Legionnaires' disease, which can be fatal. Cooling towers are often incriminated because of their potential emission of contaminated aerosols. A disinfection process for treating water is then necessary. However, current techniques often need high concentrations of chemical products which lead to ecotoxic releases into the environment. UV-H2O2 is an advanced oxidation process with a limited environmental impact (hydrogen pe...

Putois, Tamara

2012-01-01

56

Cooling towers for nuclear power  

International Nuclear Information System (INIS)

Briefly described is the design of cooling towers of the Dukovany, Mochovce and Temelin nuclear power plants. The Dukovany cooling tower is designed as an intermediate type of cooling tower for nuclear power plants with WWER-440 reactors. For the Mochovce power plant the type has been innovated by the use of plastics. The design of the Temelin cooling tower incorporates all progressive elements previously used for nuclear power plants with WWER-440 reactors. The concept of only one cooling tower for every 1000 MW unit will be introduced after 1990. (J.B.). 2 figs

57

Recent developments in cooling towers  

International Nuclear Information System (INIS)

The last few years have brought about some interesting developments in large cooling towers. Cooling tower technology and research have already been reviewed from the researcher's point of view. The present article describes some practical problems from the planning engineer's point of view. Only development trends in wet natural-draught cooling towers are considered. The shape of cooling towers has been improved as well as their internals. Hints for cooling tower operation are given on the basis of operating experience in winter. (orig.)

58

New painting on Mochovce cooling towers  

International Nuclear Information System (INIS)

New protective painting on the south cooling towers is included in the maintenance and modernization project. Slovenske elektrarne have modernized not only concrete surface of the civil structure, but also internal technology of the cooling tower and its cooing efficiency is increased without increasing consumption of the cooling water. The project will continue this and following year on towers of the units No. 1 and 2 at the Mochovce Nuclear Power Plant. Similar works have been already performed on the cooling towers on units 3 and 4 at the Bohunice Nuclear Power Plant and Mochovce Nuclear Power Plant units 3 and 4. (author)

59

Advanced dry cooling tower concept  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this year's work has been to develop a new dry cooling tower surface. The new surface utilizes a modification of film type packing in wet cooling towers. It is a concept which may eliminate excessive water loss. Cost of fabrication, and effectiveness of heat transfer surface were among the major design considerations. Based on preliminary water wetting investigations over simple geometric surfaces, a conductive plate was shaped to form a series of V-troughs. It provided open channeled water flow separated by fin-like dry surfaces, and simultaneously self distributed random spraying water. The design not only channels the water flow, but also provides a convenient means to vary the air-water interfacial area to the water-plate and dry plate contact area. Varying these ratios will become necessary as optimization studies are completed. To investigate the effectiveness of this design and of future advanced wet-dry concepts, a model heat transfer test apparatus was constructed. It provided operating conditions (water temperature, water flow rates and air flow rates) similar to those of existing wet cooling tower packing sections. All of the design requirements have been satisfied: hot water flow recirculation and counter flow air stream. A computer simulation of the proposed surface was made. The simulation modeled heat and mass transfer from the air-water interface as well as heat transfer from the dry surface area. Initial parametric runs were made using the program. They indicate that when the ratio of wet surface area to total surface area is 5 percent, approximately 75 percent of the energy transfer takes place as sensible heat transfer; whereas, for a wet tower at similar conditions approximately 85 percent of the total energy transfer takes place by evaporation.

Curcio, J.; Giebler, M.; Glicksman, L.R; Rohsenow, W.M.

1975-09-30

60

Discussion on numerical simulation techniques for patterns of water vapor rise and droplet deposition at NPP cooling tower  

International Nuclear Information System (INIS)

Based on the working principle of cooling tower, analysis and comparison are made of both advantages and disadvantages of the numerical simulation models, such as ORFAD, KUMULUS, ISCST:A, ANL/UI, CFD etc., which predict the rise and droplet deposition pattern of cooling tower water vapor. The results showed that, CFD model is currently a better model that is used of three-dimensional Renault fluid flow equations predicting the rise and droplet deposition pattern of cooling tower water vapor. The impact of the line trajectory deviation and the speed change inn plume rising is not considered in any other models, and they can not be used for prediction of particle rise and droplet deposition when a larger particle or large buildings in the direction of cooling tower. (authors)

 
 
 
 
61

The future cooling tower; Fremtidens koeletaarn  

Energy Technology Data Exchange (ETDEWEB)

This project has designed and built a pilot-scale cooling tower with an output of up to 100 kW for which good correlation has been ascertained between measured and calculated values for output and pressure loss. The new cooling tower will save approximately 15% of electricity consumption compared with the widespread dry coolers. The pilot tower uses rainwater so that both water consumption and electricity consumption are saved in softening plants. On the basis of this cooling tower, models have been made and these have been implemented in PackCalc II in order to calculate electricity and other operating savings. (Energy 11)

Ibsen, C.H. (Vestas Aircoil A/S, Lem St. (Denmark)); Schneider, P. (Teknologisk Institut, AArhus (Denmark)); Haaning, N. (Ramboell A/S, Copenhagen (Denmark)); Lund, K. (Nyrup Plast A/S, Nyrup (Denmark)); Soerensen, Ole (MultiWing A/S, Vedbaek (Denmark)); Dalsgaard, T. (Silhorko A/S, Skanderborg (Denmark)); Pedersen, Michael (Skive Kommune, Skive (Denmark))

2011-03-15

62

Ozone Treatment For Cooling Towers  

Science.gov (United States)

Report presents results of study of cooling tower in which water treated with ozone instead of usual chemical agents. Bacteria and scale reduced without pollution and at low cost. Operating and maintenance costs with treatment about 30 percent of those of treatment by other chemicals. Corrosion rates no greater than with other chemicals. Advantage of ozone, even though poisonous, quickly detected by smell in very low concentrations.

Blackwelder, Rick; Baldwin, Leroy V.; Feeney, Ellen S.

1990-01-01

63

Cooling tower with forced convection  

International Nuclear Information System (INIS)

Using air or magnetic cushions and linear motor drives, frictional losses as well as noise and wear are reduced, so that a blower of large mass can rotate economically and with high efficiency at the point where the cooling tower diameter is largest. This blower at the basis of the cooling tower consists of an endless blade row between two rotating ring elements of cooling tower diameter. (HP)

64

Advances in electrolyte cooling tower technology  

International Nuclear Information System (INIS)

Cooling towers play an important role in the production of metals by means of electrowinning. These towers are subject to severe operating conditions, and hence, standard cooling tower designs and practices are often not applicable. This paper reviews the operational requirements and conditions applicable to electrolyte cooling towers, specifically zinc electrolyte towers. Aspects covered include the physical factors influencing electrolyte cooling, cooling tower design, coupling of cooling towers to ventilation systems and environmental compliance requirements. (author)

65

Hydraulic cooling tower driver  

International Nuclear Information System (INIS)

One of the weaknesses of present day cooling tower drives are fan wrecks caused by shaft couplings breaking, gear box malfunctions due to inadequate lubrication, gear tooth wear, and inaccessibility for inspection and routine maintenance. The hydro-drive eliminates these items from the drive train and puts the same electric motor HP at ground level close coupled to a hydraulic pump, filters, and oil reservoir. Hydraulic lines bring oil pressure to the hydraulic motor, which is more than 75% less weight than comparable gear boxes and presents a smooth practically trouble free performance. In this three cell installation, the original 75 horsepower motors and 18' diameter fans were cooling a total of 14,000 GPM which were CTI tested at 74.7% of capability. The upgrading and retrofit consisted of installing at ground level 100 horsepower motors, 22' diameter fans, 14' high velocity recovery fan cylinders, V PVC splash bars, and high efficiency cellular drift eliminators. Testing indicates a 92% tower now circulating 21,000 GPM instead of the original 14,000

66

Optimizing cooling tower performance refrigeration systems, chemical plants, and power plants all have a resource quietly awaiting exploitation - cold water  

International Nuclear Information System (INIS)

The cooling towers are hidden bonanzas for energy conservation and dollar savings when properly engineered and maintained. In many cases, the limiting factor of production is the quality and quantity of cold water coming off the cooling tower. The savings accrued in energy conservation and additional product manufactured can be an important factor on the operator's company's profit and loss sheet (7). Energy management analysis is a very important consideration in today's escalating climate of costs of energy. It is advisable to consider a thorough engineering inspection and evaluation of the entire plant to leave no stone unturned iii the search to reduce energy consumption (8). The cooling tower plays the major role on waste heat removal and should be given a thorough engineering inspection and evaluation by a specialist in this field. This can be performed at nominal cost and a formal report submitted with recommendations, budget costs, and evaluation of the thermal, structural, and mechanical condition of the equipment. This feasibility study will assist in determining the extent of efficiency improvement available with costs and projected savings. It can be stated that practically all cooling towers can be upgraded to perform at higher levels of efficiency which can provide a rapid, cost-effective payback. However, while all cooling tower systems might not provide such a dramatic cost payback as these case histories, the return of a customer's investment in upgrareturn of a customer's investment in upgrading his cooling tower can be a surprising factor of operation and should not be neglected

67

Performance characteristics of a shower cooling tower  

International Nuclear Information System (INIS)

This study was prompted by the need to design towers for applications in which, due to salt deposition on the packing and subsequent blockage, the use of tower packing is not practical. In contrast to conventional cooling towers, the cooling tower analyzed in this study is void of fill. By means of efficient atomization nozzles, a shower cooling tower (SCT) is possible to be applied in industry, which, in terms of water cooling, energy saving and equipment investing, is better than conventional packed cooling towers. However, no systematic thermodynamic numerical method could be found in the literature up to now. Based on the kinetic model and mass and heat transfer model, this paper has developed a one dimensional model for studying the motional process and evaporative cooling process occurring at the water droplet level in the SCT. The finite difference approach is used for three motional processes to obtain relative parameters in each different stage, and the possibility of the droplets being entrained outside the tower is fully analyzed. The accuracy of this model is checked by practical operational results from a full scale prototype in real conditions, and some exclusive factors that affect the cooling characteristics for the SCT are analyzed in detail. This study provides the theoretical foundation for practical application of the SCT in industry

68

Top of a cooling tower  

International Nuclear Information System (INIS)

This is a supplement to DP 24 14 172.8 which refers to air slightly in motion, aiming at an improvement of the efficiency of a cooling tower, with the result that the tower's hight can be reduced while keeping up to the same capacity by means of partially lateral screening against mean and major wind velocities. This screening, which can easily be arranged onto and removed from any peripheral section of the cooling tower, is to prevent the upper cooling tower openings to be closed by side-winds passing over them. A pylon in the centre of the cooling tower overlooks its upper edge by several meters. Ropes stretched from the pylon's top to the upper tower periphery form a pyramidal pole. Its lower part may be covered with fabrics and plastics as a screening, stretching from one rope to another. When all areas will be covered they form a closed truncated cone tapering the cooling tower upwards. According to the master patent, they prevent cold air from entering the cooling tower with air slightly in motion. According to the supplement, the screening is rolled up at the side sheltered from the wind when there are major wind velocities. That part remaining at the windward side diverts the wind upwards and waste steam can escape freely on all sides. A control mechanism individually powered for rolling the (plastic or) fabric coverings is described. (HP)

69

Performance improving factors of cooling towers in thermal power plants  

International Nuclear Information System (INIS)

The condensation heat of the steam, expanding in the turbine, is transferred in condenser to the circulating water, and further in the cooling tower to the surrounding. The correct dimensioning of the cooling tower enables lowering of the condensation pressure and hereby increasing of the power of turbine. This paper presents the main characteristics of the cooling towers, the choice of which, by the designing, is of great importance for proper and successful functioning of the cooling towers. (author)

70

Application of a semi-spectral cloud water parameterization to cooling tower plumes simulations  

Science.gov (United States)

In order to simulate the plume produced by large natural draft cooling towers, a semi-spectral warm cloud parameterization has been implemented in an anelastic and non-hydrostatic 3D micro-scale meteorological code. The model results are compared to observations from a detailed field experiment carried out in 1980 at Bugey (location of an electrical nuclear power plant in the Rhône valley in East Central France) including airborne dynamical and microphysical measurements. Although we observe a slight overestimation of the liquid-water content, the results are satisfactory for all the 15 different cases simulated, which include different meteorological conditions ranging from low wind speed and convective conditions in clear sky to high wind and very cloudy. Such parameterization, which includes semi-spectral determination for droplet spectra, seems to be promising to describe plume interaction with atmosphere especially for aerosols and cloud droplets.

Bouzereau, Emmanuel; Musson Genon, Luc; Carissimo, Bertrand

2008-10-01

71

Predicting cooling tower plume dispersion  

International Nuclear Information System (INIS)

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 plumes 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. (author)

72

Factors affecting the recovery of Legionella pneumophila serogroup 1 from cooling tower water systems.  

Science.gov (United States)

A total of 20 water samples collected from the cooling towers at 20 different sites were analyzed under various conditions for the presence of Legionella pneumophila serogroup 1. A comparative assessment was performed to evaluate methods of sample collection (spray drops, beneath water at 20- to 40-cm depth, and water outlet), concentration (filtration and centrifugation), acid buffer treatment (no treatment, treatment for 3, 5, and 15 min), and CO2 incubation or candle jar incubation. The reduction in viable colonies and false negative rate were compared for the different factors. No quantitative differences in isolation of L. pneumophila serogroup 1 was found among samples collected from water at a depth of 20 to 40 cm, from water outlet, and from spray drops. Treatment in an acid buffer for 15 min significantly reduced the recovery rate, with a reduction in bacterial counts of about 40%, compared with a 3-min (12%) or a 5-min (25%) treatment. Acid buffer treatment for 3 or 5 min reduced the overgrowth of commensal flora. This treatment improved the selectivity but not the sensitivity for L. pneumophila serogroup 1. Colonies on plates incubated at 37 degrees C in a candle jar with a humidified atmosphere grew better than those incubated at 35 degrees C with 5% CO2. These results demonstrate that methods of sample collection, concentration, and incubation, but not collection site, can affect the isolation rate for L. pneumophila serogroup 1. PMID:11605805

Lu, H F; Tsou, M F; Huang, S Y; Tsai, W C; Chung, J G; Cheng, K S

2001-09-01

73

Modern cooling-tower techniques  

International Nuclear Information System (INIS)

In a general review the author deals with modern cooling-tower technique and its technical possibilities. He calls attention to output limits and discusses economic efficiency. Finally he mentions environmental questions. (orig.)

74

Legionella species and serogroups in Malaysian water cooling towers: identification by latex agglutination and PCR-DNA sequencing of isolates.  

Science.gov (United States)

In this study, we investigated the distribution of Legionella species in water cooling towers located in different parts of Malaysia to obtain information that may inform public health policies for the prevention of legionellosis. A total of 20 water samples were collected from 11 cooling towers located in three different states in east, west and south Malaysia. The samples were concentrated by filtration and treated with an acid buffer before plating on to BCYE agar. Legionella viable counts in these samples ranged from 100 to 2,000 CFU ml(-1); 28 isolates from the 24 samples were examined by latex agglutination as well as 16S rRNA and rpoB PCR-DNA sequencing. These isolates were identified as Legionella pneumophila serogroup 1 (35.7%), L. pneumophila serogroup 2-14 (39%), L. pneumophila non-groupable (10.7%), L. busanensis, L. gormanii, L. anisa and L. gresilensis. L. pneumophila was clearly the predominant species at all sampling sites. Repeat sampling from the same cooling tower and testing different colonies from the same water sample showed concurrent colonization by different serogroups and different species of Legionella in some of the cooling towers. PMID:20009251

Yong, Stacey Foong Yee; Goh, Fen-Ning; Ngeow, Yun Fong

2010-03-01

75

On some problems of operation of circulating systems with cooling tower under high hardness and mineralization of make-up water  

International Nuclear Information System (INIS)

This presentation addresses the deposit of calcium carbonate on the packings of cooling towers. The resistance of several materials to scaling is investigated as well as the effect of the scaling on the performance of the cooling tower. Water treatment to reduce scaling is also addressed

76

Application of Response Surface Methodology (RSM) for Optimization of Operating Parameters and Performance Evaluation of Cooling Tower Cold Water Temperature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The performance of a cooling tower was analyzed with various operating parameters tofind the minimum cold water temperature. In this study, optimization of operating parameters wasinvestigated. An experimental design was carried out based on central composite design (CCD) withresponse surface methodology (RSM). This paper presents optimum operating parameters and theminimum cold water temperature using the RSM method. The RSM was used to evaluate the effectsof operating variables and their in...

Ramakrishnan, Ramkumar; Arumugam, Ragupathy

2012-01-01

77

Detection of Legionella pneumophila by PCR-ELISA Method in Industrial Cooling Tower Water  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Water supply and Cooling Tower Water (CTW) are among the most common sources of Legionella pneumophila (LP) contamination. A nonradio active method is described to detect LP in industrial CTW samples. DNA was purified and amplified by nested -PCR with amplimers specific for the 16s rRNA gene of LP. The 5? end biotinylated oligomer probe was immobilized on sterptavidin B coated microtiter plates. The nested-PCR product was labeled with digoxigenin and then hybridized with 5?-biotiny...

Soheili Majid; Nejadmoghaddam Mohammad Reza; Babashamsi Mohammad; Ghasemi Jamileh; Jeddi Tehrani Mahmood

2007-01-01

78

Detection of Legionella pneumophila by PCR-ELISA Method in Industrial Cooling Tower Water  

Directory of Open Access Journals (Sweden)

Full Text Available Water supply and Cooling Tower Water (CTW are among the most common sources of Legionella pneumophila (LP contamination. A nonradio active method is described to detect LP in industrial CTW samples. DNA was purified and amplified by nested -PCR with amplimers specific for the 16s rRNA gene of LP. The 5? end biotinylated oligomer probe was immobilized on sterptavidin B coated microtiter plates. The nested-PCR product was labeled with digoxigenin and then hybridized with 5?-biotinylated probes. The amplification products were detected by using proxidase-labled anti dioxygenin antibody in a colorimetric reaction. The assay detected LP present in 1 L of 5 CTW samples examined. All of the samples were Legionella positive in both culture and PCR-ELISA methods. The PCR-ELISA assay appears to exhibit high specificity and is a more rapid technique in comparison with bacterial culture method. Thus could prove suitable for use in the routine examination of industrial CTW contamination.

Soheili Majid

2007-01-01

79

Detection of Legionella pneumophila by PCR-ELISA method in industrial cooling tower water.  

Science.gov (United States)

Water supply and Cooling Tower Water (CTW) are among the most common sources of Legionella pneumophila (LP) contamination. A nonradio active method is described to detect LP in industrial CTW samples. DNA was purified and amplified by nested -PCR with amplimers specific for the 16s rRNA gene of LP. The 5' end biotinylated oligomer probe was immobilized on sterptavidin B coated microtiter plates. The nested-PCR product was labeled with digoxigenin and then hybridized with 5'-biotinylated probes. The amplification products were detected by using proxidase-labled anti dioxygenin antibody in a colorimetric reaction. The assay detected LP present in 1 L of 5 CTW samples examined. All of the samples were Legionella positive in both culture and PCR-ELISA methods. The PCR-ELISA assay appears to exhibit high specificity and is a more rapid technique in comparison with bacterial culture method. Thus could prove suitable for use in the routine examination of industrial CTW contamination. PMID:19090273

Soheili, Majid; Nejadmoghaddam, Mohammad Reza; Babashamsi, Mohammad; Ghasemi, Jamileh; Jeddi Tehrani, Mahmood

2007-11-15

80

Treatment of cooling tower blowdown water containing silica, calcium and magnesium by electrocoagulation.  

Science.gov (United States)

This research investigated the effectiveness of electrocoagulation using iron and aluminium electrodes for treating cooling tower blowdown (CTB) waters containing dissolved silica (Si(OH)(4)), Ca(2 + ) and Mg(2 + ). The removal of each target species was measured as a function of the coagulant dose in simulated CTB waters with initial pH values of 5, 7, and 9. Experiments were also performed to investigate the effect of antiscaling compounds and coagulation aids on hardness ion removal. Both iron and aluminum electrodes were effective at removing dissolved silica. For coagulant doses < or =3 mM, silica removal was a linear function of the coagulant dose, with 0.4 to 0.5 moles of silica removed per mole of iron or aluminium. Iron electrodes were only 30% as effective at removing Ca(2 + ) and Mg(2 + ) as compared to silica. There was no measurable removal of hardness ions by aluminium electrodes in the absence of organic additives. Phosphonate based antiscaling compounds were uniformly effective at increasing the removal of Ca(2 + ) and Mg(2 + ) by both iron and aluminium electrodes. Cationic and amphoteric polymers used as coagulation aids were also effective at increasing hardness ion removal. PMID:19901466

Liao, Z; Gu, Z; Schulz, M C; Davis, J R; Baygents, J C; Farrell, J

2009-01-01

 
 
 
 
81

Discussion on Energy-saving Applications of Fanless Cooling Tower  

Directory of Open Access Journals (Sweden)

Full Text Available Cooling tower is essential to both industrial development and comfortable living. Its development is closely related to human civilization and quality of life. To achieve the cooling effects and the efficiency performance of high inlet/outlet water temperature difference (?t of cooling towers, a number of modern high technologies have been applied, while the design of cooling towers focuses on lightweight, compact size, elegant appearance, and durability. This study studied the performance of fanless cooling tower when applied in a chiller cooling water system of the central air-conditioning in a hospital and discussed the problems and solutions that the fanless cooling tower encountered during practical use and explored whether there is any room to improve energy conservation according to the data recorded in the process of operation. This study also verified the performance and advantages as specified by the manufacturer to provide a reference to the design and installation of same type cooling towers in the future.

Kuang-Cheng Yu

2011-01-01

82

Counter-Flow Cooling Tower Test Cell  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The article contains a design of a functional experimental model of a cross-flow mechanical draft cooling tower and the results and outcomes of measurements. This device is primarily used for measuring performance characteristics of cooling fills, but with a simple rebuild, it can be used for measuring other thermodynamic processes that take part in so-called wet cooling. The main advantages of the particular test cell lie in the accuracy, size, and the possibility of changing the water distr...

Dvo?ák Lukáš; Noži?ka Ji?í

2014-01-01

83

The effect of civil engineering and access conditions on the cooling water pumps and the various types of cooling water pumps for cooling towers  

International Nuclear Information System (INIS)

Starting with the pump inlet construction one can see that the designer must decide early on between the acceleration bend and the inlet chamber. To achieve smooth flow, four main conditions must be largely fulfilled. The rotor of cooling tower pumps is usually of the semiaxial type, where one must distinguish between non-adjustable, settable and adjustable rotors. The cooling tower pumps for drain and recirculation cooling are preferably made as spiral casing pumps. For nominal sizes of 1600 and larger, the pump casings are made of concrete, for economic reasons. For combined cooling, the type of pipe casing is decided for the same reasons. The above nominal size limit again decides a conrete design. Of the well-known control processes, the pre-rotor and rotor blade adjustment are at present the most economical. Both types of control are compared. (orig.)

84

Discussion on Energy-saving Applications of Fanless Cooling Tower  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cooling tower is essential to both industrial development and comfortable living. Its development is closely related to human civilization and quality of life. To achieve the cooling effects and the efficiency performance of high inlet/outlet water temperature difference (?t) of cooling towers, a number of modern high technologies have been applied, while the design of cooling towers focuses on lightweight, compact size, elegant appearance, and durability. This study studied the performance ...

Kuang-Cheng Yu; Hsin-Chang Chang; Shr-Je Hung

2011-01-01

85

Dynamic analysis of cooling towers  

International Nuclear Information System (INIS)

Natural draught cooling towers are shell structures subjected to random vibrations due to wind turbulence and earthquake. The need of big power plant units has initiated the design of very large cooling towers. The random response of such structures may be analysed using a spectral approach and assuming a linear behaviour of the structure. As the modal superposition method is the most suitable procedure for this purpose it is necessary to determine the natural frequencies and mode shapes with adequate accuracy. (orig./GL)

86

Atmospheric emissions from power plant cooling towers  

International Nuclear Information System (INIS)

Power plant recirculated cooling systems (cooling towers) are not typically thought of as potential sources of air pollution. However, atmospheric emissions can be important considerations that may influence cooling tower design and operation. This paper discusses relevant U.S. environmental regulations for potential atmospheric pollutants from power plant cooling towers, and various methods for estimating and controlling these emissions. (orig.)

87

Improved facility and sensitivity in the use of guinea pigs for the isolation of Legionella pneumophila from cooling tower water.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The established criteria for the determination of the optimum time for the sacrifice of guinea pigs inoculated with samples of cooling tower water were found to be inadequate for the detection of low levels of Legionella pneumophila. By ignoring the requirement for fever and by sequentially sacrificing the infected guinea pigs on days 3 through 5 postinoculation, we simplified the procedure, and the sensitivity of detection was improved a great deal.

Leinbach, E. D.; Winkler, H. H.; Wood, D. O.; Coggin, J. H.

1983-01-01

88

FIELD INVESTIGATION OF COOLING TOWER AND COOLING POND PLUMES  

Science.gov (United States)

Measurements were made relating to the behavior of water-vapor plumes from forced-draft cooling towers and from cooling ponds. There were three categories of measurements. (1) Ambient weather data including temperature, humidity, wind speed and wind direction. These measurements ...

89

Testing of utility power plant cooling towers  

International Nuclear Information System (INIS)

Because poor cooling tower performance can lead to expensive plant inefficiency, the number and sophistication of thermal performance tests of utility and process cooling towers is on the rise. Utility cooling tower malperformance can lead to poor heat rejection, increased turbine back pressure, increased fuel consumption, and decreased plant output. Economics demand that the towers serving these plants perform near their design point. This paper reports that cooling tower thermal performance tests can isolate one source of plant inefficiency. Benchmark tests are also performed immediately before tower rebuild or modification in order to evaluate the effectiveness of future tower alterations, or as part of a feasibility study when considering process expansion

90

Application of Response Surface Methodology (RSM for Optimization of Operating Parameters and Performance Evaluation of Cooling Tower Cold Water Temperature  

Directory of Open Access Journals (Sweden)

Full Text Available The performance of a cooling tower was analyzed with various operating parameters tofind the minimum cold water temperature. In this study, optimization of operating parameters wasinvestigated. An experimental design was carried out based on central composite design (CCD withresponse surface methodology (RSM. This paper presents optimum operating parameters and theminimum cold water temperature using the RSM method. The RSM was used to evaluate the effectsof operating variables and their interaction towards the attainment of their optimum conditions.Based on the analysis, air flow, hot water temperature and packing height were high significanteffect on cold water temperature. The optimum operating parameters were predicted using the RSMmethod and confirmed through experiment.

Ramkumar RAMAKRISHNAN

2012-01-01

91

Cooling Tower Overhaul of Secondary Cooling System in HANARO  

International Nuclear Information System (INIS)

HANARO, an open-tank-in-pool type research reactor of 30 MWth power in Korea, has been operating normally since its initial criticality in February, 1995. For the last about ten years, A cooling tower of a secondary cooling system has been operated normally in HANARO. Last year, the cooling tower has been overhauled for preservative maintenance including fills, eliminators, wood support, water distribution system, motors, driving shafts, gear reducers, basements, blades and etc. This paper describes the results of the overhaul. As results, it is confirmed that the cooling tower maintains a good operability through a filed test. And a cooling capability will be tested when a wet bulb temperature is maintained about 28 .deg. C in summer and the reactor is operated with the full power

92

EPA'S COOLING TOWER PLUME RESEARCH  

Science.gov (United States)

A comprehensive review is made of EPA's cooling tower plume research program with particular attention to plume modeling. The research began in 1969 with a modest effort to define the problem and continued through a multidisciplinary research project at a site where a single-cell...

93

WET/DRY COOLING TOWER TEST MODULE  

Science.gov (United States)

The report gives results of an evaluation of the engineering performance of a single-cell wet/dry cooling tower (about 25 MW) in an 18-month field test at San Bernardino, CA. Test objectives included determination of the water conservation and operating characteristics, and verif...

94

Analyses of cooling tower dynamics  

Science.gov (United States)

A finite element method for analyzing accurately the free vibrations of cooling towers (with column-supports) is shown to give results that are in good agreement with the experimental data obtained on both a full scale cooling tower and the corresponding model structure, and as far as the author is aware, this agreement is appreciably better than that heretofore reported for comparable studies in the literature by other workers. The theoretical method is also used successfully to explain the apparent discrepancies between the respective experimental results obtained for both model and full scale structures. The effect of foundation elasticity can be included in the method and it is shown to have a significant effect on the lower modes of a cooling tower. The usefulness of the method as a design tool is demonstrated, and as an example, the effects of changing the dimensions of the cornice, ring-beam and column-supports are studied. The angle a column-support makes with the horizontal is shown to have a noticeable effect on the lowest mode of vibration. Varying the value of Poisson's ratio is shown to have only a small effect; this vindicates the use of material in a model cooling tower that does not have quite the same value of Poisson's ratio as the full scale structure. Whilst the free vibration of cooling towers is discussed in this paper, the method can be used to analyze other rotationally periodic structures such as chimneys, and can be extended to analyze the behaviour of rotationally periodic structures subjected to seismic disturbances, impacting missiles or wind-forces.

Nelson, R. L.

1981-12-01

95

Upgrading the seismic performance of the interior water pipe supporting system of a cooling tower  

International Nuclear Information System (INIS)

This paper presents results from a numerical study that was performed in order to simulate the seismic behavior of the interior support system of the piping and cooling features of a cooling tower in one of the old power stations located in an area at the North-Western part of Greece. This cooling tower has a diameter of 60 m and a height of 100 m. The interior piping support system consists mainly of a series of nine-meter high pre-cast vertical columns made by pre-stressed concrete; these columns, together with reinforced concrete pre-cast horizontal beams that are joined monolithically with the columns at their top, form the old interior supporting system. This system represented a very flexible structure, a fact that was verified from a preliminary numerical analysis of its seismic behavior. The maximum response to the design earthquake levels resulted in large horizontal displacements at the top of the columns as well as overstress to some of the columns. The most important part of the current numerical investigation was to examine various strengthening schemes of the old interior support system and to select one that will demonstrate acceptable seismic behavior. (authors)

96

Legionella spp. in Puerto Rico cooling towers.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Water samples from air conditioning cooling towers receiving different treatment protocols on five large municipal buildings in San Juan, P.R., were assayed for various Legionella spp. and serogroups by using direct immunofluorescence. Several water quality parameters were also measured for each sample. Guinea pigs were inoculated with water samples to confirm pathogenicity and recover viable organisms. Legionella pneumophila serogroups 1 to 6, L. bozemanii, L. micdadei, L. dumoffii, and L. g...

Negro?n-alvi?ra, A.; Pe?rez-suarez, I.; Hazen, T. C.

1988-01-01

97

Treatment of auxiliary cooling tower water - influence on drainage canals and deposits  

International Nuclear Information System (INIS)

The increasingly performed turning to re-cooled power plants, as a result of the waste heat problem, in connection with the water protection, required that the technical world has to do something about the problems of preliminary stresses of the surface waters, and the cooling water quality, necessary for the operation of power plants. The thickening of the cooling water in the circulation, connected with the wet re-cooling, as a result of evaporation, requires treatment of the water, taken for cooling purposes under several quality points of view. The water treatment procedures, practical according to the latest state of todays technology, show different influences on the returned cooling water, and on the residues occuring during the treatment (in accordance with the substances separated from the receiving canal). Therefore, depending on location the individual influence factors shall be determined and valuated during the selection of the treatment procedure. Make-up water quantity, raw water quality, quality of the returned water from the receiving canal (cleaning effect for the flow). Composition and storage ability of the residues from the water treatment. (orig.)

98

Origin and prevention of infection with Legionella pneumophila through cooling towers and evaporative cooling towers  

International Nuclear Information System (INIS)

Evaporative cooling towers and industrial ventilator cooling towers have repeatedly been described as the origin of Legionnaires' disease. This article describes the design and function of cooling towers and evaporative cooling towers, sums up knowledge on the colonization of such systems with Legionella pneumophila, and describes conditions permitting the transmission of Legionella. Furthermore, design, maintenance, cleaning and disinfection measures are indicated which are believed to reduce the risk of infection through industrial and evaporative cooling towers. (orig.)

99

Cooling tower analysis consideration of environmental factors  

International Nuclear Information System (INIS)

This paper will survey the evolution of techniques used in the analysis of cooling towers over the past fifty years. It will also present two ways of analyzing the towers including the carryover on the cooling towers; performance. Cooling towers have been used in conventional fossil and nuclear power plants to remove waste heat from the condensers. This energy, in the form of low grade heat, must be transferred to the environment

100

Emergency-shutdown cooling towers: considerations in the evolution of optimum tower design  

International Nuclear Information System (INIS)

The article discusses the various regulatory requirements and criteria governing the design of emergency-shutdown cooling towers for nuclear power plants. The effects of key tower parameters (e.g., wet-bulb temperature, flow rates, and heat load) on tower size and their interactions with system and safety requirements are explored. The evolution of the Seabrook station tower and its relationship to a companion cooling-water source (the Atlantic Ocean) are presented as an example of optimum tower/system design that complies with regulatory requirements

 
 
 
 
101

Plant Vogtle cooling tower studies  

International Nuclear Information System (INIS)

Intensive ground-based field studies of plumes from two large, natural-draft cooling towers were conducted in support of the MTI modeling effort. Panchromatic imagery, IR imagery, meteorological data, internal tower temperatures and plant power data were collected during the field studies. These data were used to evaluate plume simulations, plume radioactive transfer calculations and plume volume estimation algorithms used for power estimation. Results from six field studies indicate that a 3-D atmospheric model at sufficient spatial resolution can effectively simulate a cooling tower plume if the plume is of sufficient size and the ambient meteorology is known and steady. Small plumes and gusty wind conditions degrade the agreement between the simulated and observed plumes. Thermal radiance calculations based on the simulated plumes produced maximum IR temperatures (near tower exit) which were in good agreement with measured IR temperatures for the larger plumes. For the smaller plumes, the calculated IR temperature was lower than the measured temperature by several degrees. Variations in maximum IR plume temperature with decreasing power (one reactor was undergoing a shutdown process), were clearly observed in the IR imagery and seen in the simulations. These temperature changes agreed with those calculated from an overall tower energy and momentum balance. Plume volume estimates based on camcorder images at three look angles were typically 20--30 percent larger than the plume volumes derived from the simulations, although one estimate was twice the simulated volume. Volume overestimation is expected and will have to be accounted for to some degree if plume volume is to be a useful diagnostic quantity in power estimation. Volume estimation with MTI imagery will require a large, stable plume and two looks in the visible bands (5m GSD) along with a solar shadow

102

''Novel'' types of cooling towers for the power industry  

International Nuclear Information System (INIS)

New types of cooling towers are beginning to be used abroad for the cooling circuits of nuclear power plants employing power generation units rated at 1,300 to 1,400 MW. These so-called water recovery cooling towers make use of natural draught without a droplet section. They are actually upgraded designs which were built in Europe as far back as 70 years ago. Because of the unsuitable materials then employed, these cooling towers fell into oblivion. Today, however, they are undergoing a renaissance. An upgraded design of these towers is described and compared with existing cooling towers with a droplet section. The feasibility of using these towers in Czechoslovak conditions is considered. (author)

103

[Microbial emission, immission and changes in the germ count in the cooling water during operation of wet cooling towers ii. communication: measuring methods, emission values and changes in the germ count in the cooling system (author's transl)].  

Science.gov (United States)

The second in the series "Microbial emission, immission and changes in the germ count in the cooling water of wet cooling towers" describes measuring methods and results of the measurements for determining the emission values and the changes in the germ count in the cooling system. The content of colony-forming units (KBE) in the cooling water varied widely, depending on the germ content of the surface water and the preparation of the cooling water (filtration, chemical conditioning). In summer the KBE values were as a rule higher than the values recorded in winter (factor of about 10). The introduction of cooling tower water into the surface water thus did not result in any noticeable changes in germ content, either in summer or in winter. An emission rate of 8.3 10(7) KBE/s (CSA) measured at the top of the cooling tower was the maximum emission value recorded. This resulted in a total germ content in the plume of 1.2 . 10(4) KBE/m3. In order to place this finding into perspective, it should be noted that fluctuations in the KBE values of the air of considerably more than 1000 KBE/m3 can occur because of biological release and meteorological conditions alone (see IVth communication). The KBE-P values recorded (content of particles with units which are capable of forming colonies) in the plume were of the same order as the KBE values. From this it can be concluded that the drops of cooling water which are swept away with the plume are normally only charged with individual colony-forming units. It is worth noting that the KBE values of the plume are only indirectly dependent on the KBE values of the cooling water used in the cooling tower. PMID:228514

Werner, H P; Baer, E; Dibelius, G; Dittrich, H; Ederhof, A; Egler, W; Ernst, G; Roller, W; Wurz, D

1979-09-01

104

Vortex-augmented cooling tower-windmill combination  

Science.gov (United States)

A cooling tower for cooling large quantities of effluent water from a production facility by utilizing natural wind forces includes the use of a series of helically directed air inlet passages extending outwardly from the base of the tower to introduce air from any direction in a swirling vortical pattern while the force of the draft created in the tower makes it possible to place conventional power generating windmills in the air passages to provide power as a by-product.

McAllister, Jr., John E. (Aiken, SC)

1985-01-01

105

Experimental study of cooling tower performance using ceramic tile packing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Deterioration of the packing material is a major problem in cooling towers. In this experimental study ceramic tiles were used as a packing material. The packing material is a long life burnt clay, which is normally used as a roofing material. It prevents a common problem of the cooling tower resulting from corrosion and water quality of the tower. In this study, we investigate the use of three different types of ceramic packings and evaluate their heat and mass transfer coefficients. A simpl...

Ramkumar Ramkrishnan; Ragupathy Arumugam

2013-01-01

106

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.  

Science.gov (United States)

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01). PMID:23439037

Minno?, Bihter; Ilhan-Sungur, Esra; Çotuk, Ay??n; Güngör, Nihal Do?ruöz; Cansever, Nurhan

2013-01-01

107

The study on the evaporation cooling efficiency and effectiveness of cooling tower of film type  

International Nuclear Information System (INIS)

Based on heat and mass transport mechanism of film type cooling, which was combined with an on-site test on counter flow film type cooling tower, a mathematical model on the evaporation and cooling efficiency and effectiveness has been developed. Under typical climatic conditions, air conditioning load and the operating condition, the mass and heat balances have been calculated for the air and the cooling water including the volume of evaporative cooling water. Changing rule has been measured and calculated between coefficient of performance (COP) and chiller load. The influences of air and cooling water parameters on the evaporative cooling efficiency were analyzed in cooling tower restrained by latent heat evaporative cooling, and detailed derivation and computation revealed that both the evaporative cooling efficiency and effectiveness of cooling tower are the same characteristics parameters of the thermal performance of a cooling tower under identical assumptions.

108

Use of cooling tower blow down in ethanol fermentation.  

Science.gov (United States)

Reducing water consumption in bioethanol production conserves an increasingly scarce natural resource, lowers production costs, and minimizes effluent management issues. The suitability of cooling tower blow down water for reuse in fermentation was investigated as a means to lower water consumption. Extensive chemical characterization of the blow down water revealed low concentrations of toxic elements and total dissolved solids. Fermentation carried out with cooling tower blow down water resulted in similar levels of ethanol and residual glucose as a control study using deionized water. The study noted good tolerance by yeast to the specific scale and corrosion inhibitors found in the cooling tower blow down water. This research indicates that, under appropriate conditions, reuse of blow down water from cooling towers in fermentation is feasible. PMID:21076211

Rajagopalan, N; Singh, V; Panno, B; Wilcoxon, M

2010-01-01

109

Wet or wet/dry cooling tower  

International Nuclear Information System (INIS)

A wet or wet/dry cooling tower is described having heat exchanger elements to provide heat exchange between water and cooling air and having an arrangement for transferring the cooled water to a return to the water distribution, the same having below the heat exchanger elements a number of adjacent inclined run-off surfaces, water-guiding plates into which the bottom longitudinal edges of the run-off surfaces merge, the plates having vertical areas and having channels which are disposed one above another and which extend transversely of the substantially vertical cooling-air flow, and water-collecting troughs which are disposed perpendicularly to the water-guiding plates at the bottom end of the lateral vertical edges of such plates, the run-off surfaces covering the distance between two adjacent water-guiding plates, the channels extending at an inclination to the horizontal and terminating in lateral vertical edges of such plates, characterised in that the run-off surfaces are connected by way of edged or rounded transition zones to the surface zones of the water-guiding plates and the channels are embodied by guide-groove structures which are stamped out of the surface zones at least on one side and which supply at least from the transition zones the cooling water from the run-off surfaces to the water-collecting troughs with the use of the surface tension of such water. 10 figs

110

Method for dimensioning crossflow cooling towers  

International Nuclear Information System (INIS)

EDF has started a research programme relating to the operation of crossflow cooling towers. Tests have been conducted at the Nantes-Chevire bench as part of this programme: different fill configurations have been tested, varying the height and depth of the splash bars and the type of distribution nozzles. Measurements have also been taken in large cooling towers coupled with 900 MW(e) nuclear units. Test bench and on-site measurements consisted of vertical temperature and air velocity profiles at the inlet and outlet of the fill, as well as horizontal flow and water temperature profiles at the base of the fill. These readings have revealed horizontal transfer phenomena of the water flow and vertical transfer of the air flow, which are not portrayed by small test benches. These phenomena have been taken into account in a simplified two dimensional computation model of a crossflow fill, integrated to the TEFERI model. The results secured by computation using the exchange laws measured using the Nantes test bench are in good agreement with on-site measurements. This method has been applied to the prediction of efficiency of large cooling towers coupled with 1300 MW units and to the study of possible improvements to their operation

111

Aerodynamic design of cooling tower drift eliminators  

Energy Technology Data Exchange (ETDEWEB)

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. Thus 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.

Yao, S.C. (Argonne National Lab., IL); Schrock, V.E.

1976-10-01

112

Improving the efficiency of natural draft cooling towers  

Energy Technology Data Exchange (ETDEWEB)

This study shows how the efficiency of a natural draft cooling tower can be improved by optimising the heat transfer along the cooling tower (CT) packing using a suitable water distribution across the plane area of the cooling tower. On the basis of cooling air measurements, it is possible to distribute the water in such a way that it approaches the optimal local water/air mass flow ratio and ensures the homogeneity of the heat transfer and a reduction of entropy generation, thus minimising the amount of exergy lost. The velocity and temperature fields of the air flow were measured with the aid of a remote control mobile robot unit that was developed to enable measurements at an arbitrary point above the spray zone over the entire plane area of the cooling tower. The topological structures of the moist air velocity profiles and the temperature profiles above the spray zone were used as input data for calculation of the local entropy generation in the tower. On the basis of the measured boundary conditions, a numerical analysis of the influence of the water distribution across the cooling tower's plane area on entropy generation and exergy destruction in the cooling tower was conducted.

Smrekar, J. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia); Oman, J. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia)]. E-mail: janez.oman@fs.uni-lj.si; Sirok, B. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia)

2006-06-15

113

Improving the efficiency of natural draft cooling towers  

International Nuclear Information System (INIS)

This study shows how the efficiency of a natural draft cooling tower can be improved by optimising the heat transfer along the cooling tower (CT) packing using a suitable water distribution across the plane area of the cooling tower. On the basis of cooling air measurements, it is possible to distribute the water in such a way that it approaches the optimal local water/air mass flow ratio and ensures the homogeneity of the heat transfer and a reduction of entropy generation, thus minimising the amount of exergy lost. The velocity and temperature fields of the air flow were measured with the aid of a remote control mobile robot unit that was developed to enable measurements at an arbitrary point above the spray zone over the entire plane area of the cooling tower. The topological structures of the moist air velocity profiles and the temperature profiles above the spray zone were used as input data for calculation of the local entropy generation in the tower. On the basis of the measured boundary conditions, a numerical analysis of the influence of the water distribution across the cooling tower's plane area on entropy generation and exergy destruction in the cooling tower was conducted

114

Dynamic interaction effects in cooling tower groups  

International Nuclear Information System (INIS)

A theoretical and experimental determination of the dynamic response of reinforced concrete cooling towers, taking into consideration group effects, are described. The results for an individual tower are thoroughly examined. A complete analysis is then performed for the critical wind orientations, for each tower in a six towers group. It's shown that ignoring group effects in the analysis may lead to a significant underestimation of the structural response. (E.G.)

115

AIRBORNE MONITORING OF COOLING TOWER EFFLUENTS. VOLUME I. TECHNICAL SUMMARY  

Science.gov (United States)

MRI conducted an airborne plume monitoring program as part of the Chalk Point Cooling Tower Project. Plume measurement included: temperature, dew point, visibility, turbulence, droplet size distribution and concentration, liquid water content, sodium chloride concentration (NaCl)...

116

Cooling towers of nuclear power plants  

International Nuclear Information System (INIS)

The specifications are given of cooling towers of foreign nuclear power plants and a comparison is made with specifications of cooling towers with natural draught in Czechoslovak nuclear power plants. Shortcomings are pointed out in the design of cooling towers of Czechoslovak nuclear power plants which have been derived from conventional power plant design. The main differences are in the adjustment of the towers for winter operation and in the designed spray intensity. The comparison of selected parameters is expressed graphically. (J.B.)

117

Ozone inhibits corrosion in cooling towers  

Science.gov (United States)

Commercially available corona discharge ozone generator, fitted onto industrial cooling tower, significantly reduces formation of scales (calcium carbonate) and corrosion. System also controls growth of algae and other microorganisms. Modification lowers cost and improves life of cooling system.

French, K. R.; Howe, R. D.; Humphrey, M. F.

1980-01-01

118

Observed cooling tower plume characteristics  

International Nuclear Information System (INIS)

In-plume measurements with an instrumented Cessna 411 aircraft were made at the Rancho Seco Nuclear Generating Station (913 MWe) near Sacramento, California; the Trojan nuclear plant (1130 MWe) on the Columbia River 50 mi. north of Portland, Oregon; and the coal-fired Centralia Steam Plant (1400 MWe) 50 mi. north of the Trojan plant. Additional surface-based operations conducted at Rancho Seco included pibal tracking to determine the wind velocity profile, time-exposure photographs of the plume for external plume definition and measurements of sulfate deposition due to the drift of entrained circulating water. Heat rejection at Rancho Seco is from two 425 ft. natural-draft towers whose exit diameters are 195 ft; at Trojan, from a single 500 ft. natural-draft tower with exit diameter of 250 ft; and at Centralia, from four mechanical-draft towers. Results of the analyses to date are summarized for three days' operation at Rancho Seco (February 17, 18, and 20 in 1975) and one day (May 13, 1976) at Trojan and Centralia. During the course of these flights, measurements of temperature, humidity, turbulence, Aitken nuclei, and cloud droplet spectra were taken

119

Optimization of cooling tower performance analysis using Taguchi method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study discuss the application of Taguchi method in assessing maximum cooling tower effectiveness for the counter flow cooling tower using expanded wire mesh packing. The experiments were planned based on Taguchi’s L27 orthogonal array .The trail was performed under different inlet conditions of flow rate of water, air and water temperature. Signal-to-noise ratio (S/N) analysis, analysis of variance (ANOVA) and regression were carried out in order to determine the effects of proce...

Ramkumar Ramakrishnan; Ragupathy Arumugam

2013-01-01

120

Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, ...

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P.; Packman, Aaron

2009-01-01

 
 
 
 
121

Studies on the conditioning of line-decarbonized cooling-tower make-up feedwater for use as secondary cooling water  

International Nuclear Information System (INIS)

Conditioned Danube water is used in the Gundremmingen nuclear power plant, units B + C, for cooling conventional cooling sites (service water) prior to its application as cooling-tower make-up feedwater. Conditioning is effected by decarbonization using lime (2Ksub(S8.2) proportional Ksub(S4.3); pH proportional 10) with subsequent dosing of hardness stabilizers. The pipelines of the service water system are made of non-alloy non-coated steel and the heat exchanger tubes are largely made of special-grade brass 71 and pure copper. The occurrence of sludge-like deposits in the heat exchanger tubes and strong, partly blister-type formation of deposits on the ferritic pipe surfaces during commissioning caused the examination of different conditioning methods in a test cooling facility while simulating real conditions at 'on-site' operation. One single product out of the range of conditioners tested did not exhibit the formation of sludge-type deposits on the heat exchanger tubes, thus rendering any extra chlorination unnecessary to-date. Assessment of the corrosion behaviour of the C-steel showed operation with decarbonized water at pH proportional 10 to be superior to those employing a reduced pH. (orig./RB)

122

Distribution of sequence-based types of legionella pneumophila serogroup 1 strains isolated from cooling towers, hot springs, and potable water systems in China.  

Science.gov (United States)

Legionella pneumophila serogroup 1 causes Legionnaires' disease. Water systems contaminated with Legionella are the implicated sources of Legionnaires' disease. This study analyzed L. pneumophila serogroup 1 strains in China using sequence-based typing. Strains were isolated from cooling towers (n = 96), hot springs (n = 42), and potable water systems (n = 26). Isolates from cooling towers, hot springs, and potable water systems were divided into 25 sequence types (STs; index of discrimination [IOD], 0.711), 19 STs (IOD, 0.934), and 3 STs (IOD, 0.151), respectively. The genetic variation among the potable water isolates was lower than that among cooling tower and hot spring isolates. ST1 was the predominant type, accounting for 49.4% of analyzed strains (n = 81), followed by ST154. With the exception of two strains, all potable water isolates (92.3%) belonged to ST1. In contrast, 53.1% (51/96) and only 14.3% (6/42) of cooling tower and hot spring, respectively, isolates belonged to ST1. There were differences in the distributions of clone groups among the water sources. The comparisons among L. pneumophila strains isolated in China, Japan, and South Korea revealed that similar clones (ST1 complex and ST154 complex) exist in these countries. In conclusion, in China, STs had several unique allelic profiles, and ST1 was the most prevalent sequence type of environmental L. pneumophila serogroup 1 isolates, similar to its prevalence in Japan and South Korea. PMID:24463975

Qin, Tian; Zhou, Haijian; Ren, Hongyu; Guan, Hong; Li, Machao; Zhu, Bingqing; Shao, Zhujun

2014-04-01

123

Possible cooling tower designs and their economy  

International Nuclear Information System (INIS)

The supporting shells of natural-draught cooling towers make very high demands on calculation and construction. Of the possible constructions, reinforced-concrete cooling towers constructed with the aid of climbing forms are the only ones which appear to be functional and economical. THe choice of the meridian curve of the cooling tower shell, which may be a hyperboloid of revolution or, in a more recent construction, of bell shape, is of great importance. In very large cooling towers, bracing rings cannot be dispensed with, as they improve the buckling and vibrational behaviour of the shell. This type of construction is also more economical than cooling tower shell with continuously varying shell thickness. (orig.)

124

40 CFR 63.1329 - Process contact cooling towers provisions.  

Science.gov (United States)

...2010-07-01 true Process contact cooling towers provisions...Pollutant Emissions: Group IV Polymers and Resins § 63.1329 Process contact cooling towers provisions...sent to the process contact cooling tower. ...(2) Measuring an alternative parameter,...

2010-07-01

125

40 CFR 63.1329 - Process contact cooling towers provisions.  

Science.gov (United States)

...2010-07-01 true Process contact cooling towers provisions. 63.1329 Section... § 63.1329 Process contact cooling towers provisions. (a) The...that utilizes a process contact cooling tower shall comply with...

2010-07-01

126

On the prospects for dry cooling tower building in FRG  

International Nuclear Information System (INIS)

Advantages and disadvantages of dry cooling towers for NPPs are considered. Construction of a number of cooling towers in FRY are described. The advisability of building cooling towers of a combined type - with wet aud dry sections is noted

127

Comparison of plate counts, Petrifilm, dipslides, and adenosine triphosphate bioluminescence for monitoring bacteria in cooling-tower waters.  

Science.gov (United States)

Effective bacterial control in cooling-tower systems requires accurate and timely methods to count bacteria. Plate-count methods are difficult to implement on-site, because they are time- and labor-intensive and require sterile techniques. Several field-applicable methods (dipslides, Petrifilm, and adenosine triphosphate [ATP] bioluminescence) were compared with the plate count for two sample matrices--phosphate-buffered saline solution containing a pure culture of Pseudomonas fluorescens and cooling-tower water containing an undefined mixed bacterial culture. For the pure culture, (1) counts determined on nutrient agar and plate-count agar (PCA) media and expressed as colony-forming units (CFU) per milliliter were equivalent to those on R2A medium (p = 1.0 and p = 1.0, respectively); (2) Petrifilm counts were not significantly different from R2A plate counts (p = 0.99); (3) the dipslide counts were up to 2 log units higher than R2A plate counts, but this discrepancy was not statistically significant (p = 0.06); and (4) a discernable correlation (r2 = 0.67) existed between ATP readings and plate counts. For cooling-tower water samples (n = 62), (1) bacterial counts using R2A medium were higher (but not significant; p = 0.63) than nutrient agar and significantly higher than tryptone-glucose yeast extract (TGE; p = 0.03) and PCA (p < 0.001); (2) Petrifilm counts were significantly lower than nutrient agar or R2A (p = 0.02 and p < 0.001, respectively), but not statistically different from TGE, PCA, and dipslides (p = 0.55, p = 0.69, and p = 0.91, respectively); (3) the dipslide method yielded bacteria counts 1 to 3 log units lower than nutrient agar and R2A (p < 0.001), but was not significantly different from Petrifilm (p = 0.91), PCA (p = 1.00) or TGE (p = 0.07); (4) the differences between dipslides and the other methods became greater with a 6-day incubation time; and (5) the correlation between ATP readings and plate counts varied from system to system, was poor (r2 values ranged from < 0.01 to 0.47), and the ATP method was not sufficiently sensitive to measure counts below approximately 10(4) CFU/mL. PMID:19445329

Mueller, Sherry A; Anderson, James E; Kim, Byung R; Ball, James C

2009-04-01

128

The possibility of the free cooling with cooling towers according to a study of the actual conditions of cooling towers  

International Nuclear Information System (INIS)

This paper reports that based on the results of a study that was conducted in winter on the state of a combined refrigerating machine and cooling tower refrigeration system in an existing large-scale DHC facility, heat load valuations and the actual performance of the cooling towers were quantitatively obtained, based on which the possibility of free cooling, from which energy savings can be expected, was verified. Based on an analysis of the relationship of the circulating water in the cooling tower during free cooling, to the outlet water temperature and the heat load, it was determined that, during a typical winter period, 850 m3/h of circulating water would be needed to remove a heat load equivalent to the manufacturing heat load from the refrigerating machines. In free cooling with 850 m3/h of circulating water, the outlet water temperature is 8.2 degrees C, or about 1.3 times as high as the outlet water temperature from the refrigerating machines. However, due to lower thermal unit of free cooling, an energy savings of about 60% can be achieved

129

Corrosion control when using secondary treated municipal wastewater as alternative makeup water for cooling tower systems.  

Science.gov (United States)

Secondary treated municipal wastewater is a promising alternative to fresh water as power plant cooling water system makeup water, especially in arid regions. Laboratory and field testing was conducted in this study to evaluate the corrosiveness of secondary treated municipal wastewater for various metals and metal alloys in cooling systems. Different corrosion control strategies were evaluated based on varied chemical treatment. Orthophosphate, which is abundant in secondary treated municipal wastewater, contributed to more than 80% precipitative removal of phosphorous-based corrosion inhibitors. Tolyltriazole worked effectively to reduce corrosion of copper (greater than 95% inhibition effectiveness). The corrosion rate of mild steel in the presence of free chlorine 1 mg/L (as Cl2) was approximately 50% higher than in the presence of monochloramine 1 mg/L (as Cl2), indicating that monochloramine is a less corrosive biocide than free chlorine. The scaling layers observed on the metal alloys contributed to corrosion inhibition, which could be seen by comparing the mild steel 21-day average corrosion rate with the last 5-day average corrosion rate, the latter being approximately 50% lower than the former. PMID:21214028

Hsieh, Ming-Kai; Li, Heng; Chien, Shih-Hsiang; Monnell, Jason D; Chowdhury, Indranil; Dzombak, David A; Vidic, Radisav D

2010-12-01

130

Cooling tower drift: experiment design for comprehensive case study  

International Nuclear Information System (INIS)

A comprehensive experimental study of drift emissions and deposition from a mechanical draft cooling tower is planned for early spring 1978. The field effort is to measure rates of mineral mass and drift water emissions and depositions downwind from a suitable power plant. Measurements of drift droplet size distributions, cooling tower temperature and velocity profiles, and ambient meteorological parameters are also to be made. From these measurements, a data base can be developed which can be used for validating models of drift deposition from cooling towers

131

The effects of natural winds on cooling towers  

International Nuclear Information System (INIS)

Natural winds can affect both the thermal performance and structural design of cooling towers. From the thermal performance viewpoint the severity of wind effects is dependent upon the type of cooling tower being considered. In general, natural winds can cause stripping of falling water near the peripherary of the air inlet, reversal of the airflow into the tower and changes in the recooled water temperature. In the context of C.E.G.B. experience, these effects will be discussed with particular regard to remedial measures and predictive methods. From the structural design viewpoint the effects of natural winds are very important. It has been established that the shells of cooling towers vibrate at their resonant frequencies due to the turbulent nature of the incident wind. Consequently, in evaluating the wind induced stresses in cooling tower shells, it is essential to consider not only the static and quasi-static response of the shell but also its resonant response. As the fluctuating wind loading distribution on the surface of a cooling tower on a particular site cannot be defined explicitly at this time, it is necessary to evaluate wind induced stresses in a shell of a proposed design using wind tunnel test results appropriate to the site under consideration. The development of these wind tunnel test techniques and the results obtained for a typical C.E.G.B. cooling tower installation will be discussed

132

Different types of cooling towers influence the design and the conditions of the inlet of cooling water pumps  

International Nuclear Information System (INIS)

Possible solutions of performance and number of cooling water pumps to be installed for 300 mw conventional to 2000 mw nuclear unit powers are shown. As four influencing parameters greatly vary, each pump is individually manufactured. The specific fast-running pumps are sensitive to disturbances on the suction side. 11 examples for the useful shape of chambers and arched beams of the inlet building are given according to their importance. Characteristic and proved inlet chamber types were determined by electron-analog tests and model tests. What one understands by non-destructive flow to the pumps, is determined by means of four criteria, e.g. cavitation and NPSH value (net positive suction head) or according to DIN 'Haltedruckhoehe'. As all four criteria cannot be fulfilled to a maximum, one must be able to decide between them. The constructions of cooling water pumps, pipe and spiral casing with variation are treated in nine examples. Finally, the types of control are discussed. Construction and fabrication of a single cooling pump for a 1300 mw unit would be possible today; pressure joints diameter 4500 mm. (orig.)

133

Proceedings: Cooling tower and advanced cooling systems conference  

International Nuclear Information System (INIS)

This Cooling Tower and Advanced Cooling Systems Conference was held August 30 through September 1, 1994, in St. Petersburg, Florida. The conference was sponsored by the Electric Power Research Institute (EPRI) and hosted by Florida Power Corporation to bring together utility representatives, manufacturers, researchers, and consultants. Nineteen technical papers were presented in four sessions. These sessions were devoted to the following topics: cooling tower upgrades and retrofits, cooling tower performance, cooling tower fouling, and dry and hybrid systems. On the final day, panel discussions addressed current issues in cooling tower operation and maintenance as well as research and technology needs for power plant cooling. More than 100 people attended the conference. This report contains the technical papers presented at the conference. Of the 19 papers, five concern cooling tower upgrades and retrofits, five to cooling tower performance, four discuss cooling tower fouling, and five describe dry and hybrid cooling systems. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

134

Noise emissions of cooling towers; Geraeuschemissionen von Kuehltuermen  

Energy Technology Data Exchange (ETDEWEB)

Cooling towers are often large structures with high sound emission. The impact of water drops on the water surface in the collecting basin leads to the generation of middle- and high-frequency noise that is emitted via the air intake opening and the outlet. In forced-draft cooling towers, additional noise is generated by drives and fans. The sound emissions can be predicted by means of empirical calculation models. In this way, noise control measures can be taken into account already at an early phase of planning. Different, proven measures for reduction of sound emissions are taken depending on cooling tower design. Regulations on noise acceptance testing for cooling towers are given in various standards. (orig.)

Hinkelmann, Dirk [Mueller-BBM GmbH, Gelsenkirchen (Germany)

2013-09-01

135

Optimization of cooling tower performance analysis using Taguchi method  

Directory of Open Access Journals (Sweden)

Full Text Available This study discuss the application of Taguchi method in assessing maximum cooling tower effectiveness for the counter flow cooling tower using expanded wire mesh packing. The experiments were planned based on Taguchi’s L27 orthogonal array .The trail was performed under different inlet conditions of flow rate of water, air and water temperature. Signal-to-noise ratio (S/N analysis, analysis of variance (ANOVA and regression were carried out in order to determine the effects of process parameters on cooling tower effectiveness and to identity optimal factor settings. Finally confirmation tests verified this reliability of Taguchi method for optimization of counter flow cooling tower performance with sufficient accuracy.

Ramkumar Ramakrishnan

2013-01-01

136

Experimental study of cooling tower performance using ceramic tile packing  

Directory of Open Access Journals (Sweden)

Full Text Available Deterioration of the packing material is a major problem in cooling towers. In this experimental study ceramic tiles were used as a packing material. The packing material is a long life burnt clay, which is normally used as a roofing material. It prevents a common problem of the cooling tower resulting from corrosion and water quality of the tower. In this study, we investigate the use of three different types of ceramic packings and evaluate their heat and mass transfer coefficients. A simple comparison of packing behaviour is performed with all three types of packing materials. The experimental study was conducted in a forced draft cooling tower. The variations in many variables, which affect the tower efficiency, are described.

Ramkumar Ramkrishnan

2013-03-01

137

Performance characteristics of counter flow wet cooling towers  

International Nuclear Information System (INIS)

Cooling towers are one of the biggest heat and mass transfer devices that are in widespread use. In this paper, we use a detailed model of counter flow wet cooling towers in investigating the performance characteristics. The validity of the model is checked by experimental data reported in the literature. The thermal performance of the cooling towers is clearly explained in terms of varying air and water temperatures, as well as the driving potential for convection and evaporation heat transfer, along the height of the tower. The relative contribution of each mode of heat transfer rate to the total heat transfer rate in the cooling tower is established. It is demonstrated with an example problem that the predominant mode of heat transfer is evaporation. For example, evaporation contributes about 62.5% of the total rate of heat transfer at the bottom of the tower and almost 90% at the top of the tower. The variation of air and water temperatures along the height of the tower (process line) is explained on psychometric charts

138

The Schmehausen cable net cooling tower  

International Nuclear Information System (INIS)

The prototype of a large cable net shell as a natural-draught cooling tower for the THTR-300 is presented. Results of wind tunnel tests and calculations are given, and the capacity is discussed. Design features of the main components are presented in illustrations and are described with regard to the construction process of the cooling tower. Finally, it is shown that the cable net cooling tower is a suitable construction for large dimensions and caving-in or seismic areas. (orig./HP)

139

Measurements of cooling tower plumes. Pt. 2  

International Nuclear Information System (INIS)

The use of Lidar-Systems to detect the plumes of dry or wet cooling towers shows definite advantages compared with other measuring techniques. Two test measurements with the Lidar-Systems of the DWD Meteorological Observatory Aachen (BRD) are described. The measurements of the dry cooling tower plume at the Preussag power Ibbenbueren (BRD) show that the smoke produced by a few smoke candles is a good Lidar-tracer for the warm air. FORTRAN programs for the transformation of the Lidar signals into reflectivity isolines are discussed with reference to the results from the wet cooling tower plume measurements of the RWE power station Weisweiler I (BRD). (orig.)

140

The effect of evaporation losses in the analysis of crossflow cooling towers  

International Nuclear Information System (INIS)

The Merkel method for the thermal design of counterflow and crossflow cooling towers neglects the variation of the water flow from the tower inlet to outlet. It has been shown that neglecting the water evaporation losses introduces inaccuracies in the performance calculation of counterflow cooling towers. This study develops a method for including these evaporation losses and demonstrates that the error in the Merkel method for crossflow cooling towers may reach 20% depending on the design conditions. (Auth.)

 
 
 
 
141

Causes and control of cooling tower film fill deposits  

International Nuclear Information System (INIS)

Plastic film-type cooling tower fill material is used throughout the utility industry because of its excellent cooling capabilities, compact design, and durability. The remarkable heat rejection of these so-called high efficiency fill materials is due to its ability to form a film of water on a tremendous surface area. For example, hot (80-100 degrees F) recirculating water that is distributed over the cooling tower can be cooled up to 30 degrees with only a 3-4 feet depth of this fill material. By contrast, conventional splash bar cooling tower fill acts by forming droplets can require a volume many times that of film fill to achieve the same drop in cooling water temperature. This paper reports that over the past several years, the utility industry has learned that these high efficiency cooling tower fill materials are subject to fouling, despite the manufacturer or subtle differences in fill design. With certain types of makeup water quality and tower operating practices, it is sometimes impossible to avoid fouling the fill without chemical treatments to control the progression of deposit formation

142

Hybrid cooling tower Neckarwestheim 2 cooling function, emission, plume dispersion  

International Nuclear Information System (INIS)

The fan-assisted hybrid cooling tower of the 1300 MW power plant Gemeinschafts-Kernkraftwerk Neckarwestheim 2 was designed and constructed based on results from theoretical and experimental studies and experiences from a smaller prototype. The wet part acts in counterflow. The dry part is arranged above the wet part. Each part contains 44 fans. Special attention was payed to the ducts which mix the dry into the wet plume. The cooling function and state, mass flow and contents of the emission were measured. The dispersion of the plume in the atmosphere was observed. The central results are presented in this paper. The cooling function corresponds to the predictions. The content of drifted cooling water in the plume is extremely low. The high velocity of the plume in the exit causes an undisturbed flow into the atmosphere. The hybrid operation reduces visible plumes strongly, especially in warmer and drier ambient air

143

Design and operation of hybrid cooling towers  

International Nuclear Information System (INIS)

The first hybrid cooling tower at a coal-fired power station with a waste heat output of 550 MW has been in operation since the middle of 1985. Experience during the construction stage and the initial period of operation has confirmed the correctness of the design standards and of the design itself and, of course, also offers a wealth of knowledge to be observed on future construction projects. A second cooling tower of similar design is being erected at the present time. This cooling tower serves a power station unit with 2500 MW of waste heat output. The programme for this cooling tower offers the possibility for all the accumulated and evaluated experience to be of influence both on the design and also on the method of operation. This paper reports on the details. (orig.)

144

On thermal performance of seawater cooling towers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Seawater cooling towers have been used since the 1970s 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 that govern the thermal performance of cooling towers, including vapor pre...

Sharqawy, Mostafa H.; Lienhard, John H.; Zubair, Syed M.

2010-01-01

145

Dry cooling tower operating experience in the LOFT reactor  

International Nuclear Information System (INIS)

A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features

146

Solution and scope of utilization of the cross-stream cooling towers  

International Nuclear Information System (INIS)

Technical solutions and operational properties of the cross-stream cooling towers as well as the scope of their utilization are presented. The differences within thermodynamic calculations of the cross-stream and counter-stream cooling towers due to the direction of the air flow as well as water flow in sprinkling system are discussed. The assessment of the capital and operational costs of the cross-stream cooling towers is given and compared with the cost of counter-stream cooling towers (utilizing as an example a calculation conducted for the cooling towers of the 720, 1100 and 1400 MW units). (author). 6 refs, 9 figs

147

MATHEMATICAL MODELING OF EMISSIONS FROM COOLING TOWERS USING COAL GASIFICATION WASTEWATER  

Science.gov (United States)

The report describes a computer program that calculates atmospheric emissions from counterflow cooling towers when using pretreated coal gasification wastewaters as tower makeup water. Air stripping and biological oxidation are both incorporated into the mathematical model as pos...

148

Built-in cooling device for cooling towers  

International Nuclear Information System (INIS)

For a universal grate as a construction element of cooling towers design information is given. The grate may, in a single form, be superposed as often as is desired with spacers in between. It meets the requirement that the four edges of all grates may be put vertically one over the other and that falling water drops, after passing about four grates, will hit one of the baffle plates, with which the intersections of the webs, forming the grates, are provided. The water running down from top to bottom is thus forced to permanently change the flow direction, resulting in maximum turbulence, distribution and cooling. The grates are turned by 90 degrees from one platform to another. (HP)

149

Counter-Flow Cooling Tower Test Cell  

Directory of Open Access Journals (Sweden)

Full Text Available The article contains a design of a functional experimental model of a cross-flow mechanical draft cooling tower and the results and outcomes of measurements. This device is primarily used for measuring performance characteristics of cooling fills, but with a simple rebuild, it can be used for measuring other thermodynamic processes that take part in so-called wet cooling. The main advantages of the particular test cell lie in the accuracy, size, and the possibility of changing the water distribution level. This feature is very useful for measurements of fills of different heights without the influence of the spray and rain zone. The functionality of this test cell has been verified experimentally during assembly, and data from the measurement of common film cooling fills have been compared against the results taken from another experimental line. For the purpose of evaluating the data gathered, computational scripts were created in the MATLAB numerical computing environment. The first script is for exact calculation of the thermal balance of the model, and the second is for determining Merkel’s number via Chebyshev’s method.

Dvo?ák Lukáš

2014-03-01

150

Counter-Flow Cooling Tower Test Cell  

Science.gov (United States)

The article contains a design of a functional experimental model of a cross-flow mechanical draft cooling tower and the results and outcomes of measurements. This device is primarily used for measuring performance characteristics of cooling fills, but with a simple rebuild, it can be used for measuring other thermodynamic processes that take part in so-called wet cooling. The main advantages of the particular test cell lie in the accuracy, size, and the possibility of changing the water distribution level. This feature is very useful for measurements of fills of different heights without the influence of the spray and rain zone. The functionality of this test cell has been verified experimentally during assembly, and data from the measurement of common film cooling fills have been compared against the results taken from another experimental line. For the purpose of evaluating the data gathered, computational scripts were created in the MATLAB numerical computing environment. The first script is for exact calculation of the thermal balance of the model, and the second is for determining Merkel's number via Chebyshev's method.

Dvo?ák, Lukáš; Noži?ka, Ji?í

2014-03-01

151

Investigation of N-acyl homoserine lactone (AHL) molecule production in Gram-negative bacteria isolated from cooling tower water and biofilm samples.  

Science.gov (United States)

In this study, 99 Gram-negative rod bacteria were isolated from cooling tower water, and biofilm samples were examined for cell-to-cell signaling systems, N-acyl homoserine lactone (AHL) signal molecule types, and biofilm formation capacity. Four of 39 (10 %) strains isolated from water samples and 14 of 60 (23 %) strains isolated from biofilm samples were found to be producing a variety of AHL signal molecules. It was determined that the AHL signal molecule production ability and the biofilm formation capacity of sessile bacteria is higher than planktonic bacteria, and there was a statistically significant difference between the AHL signal molecule production of these two groups (p cooling tower water and biofilm samples produced different types of AHL signal molecules and that there were different types of AHL signal molecules in an AHL extract of bacteria. In the present study, it was observed that different isolates of the same strains did not produce the same AHLs or did not produce AHL molecules, and bacteria known as AHL producers did not produce AHL. These findings suggest that detection of signal molecules in bacteria isolated from cooling towers may contribute to prevention of biofilm formation, elimination of communication among bacteria in water systems, and blockage of quorum-sensing controlled virulence of these bacteria. PMID:23250628

Haslan, Ezgi; Kimiran-Erdem, Ayten

2013-09-01

152

Distribution of Monoclonal Antibody Subgroups and Sequence-Based Types among Legionella pneumophila Serogroup 1 Isolates Derived from Cooling Tower Water, Bathwater, and Soil in Japan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Legionella pneumophila serogroup (SG) 1 is the most frequent cause of legionellosis. This study analyzed environmental isolates of L. pneumophila SG 1 in Japan using monoclonal antibody (MAb) typing and sequence-based typing (SBT). Samples were analyzed from bathwater (BW; n = 50), cooling tower water (CT; n = 50), and soil (SO; n = 35). The distribution of MAb types varied by source, with the most prevalent types being Bellingham (42%), Oxford (72%), and OLDA (51%) in BW, CT, and SO, respect...

Amemura-maekawa, Junko; Kikukawa, Kiyomi; Helbig, Ju?rgen H.; Kaneko, Satoko; Suzuki-hashimoto, Atsuko; Furuhata, Katsunori; Chang, Bin; Murai, Miyo; Ichinose, Masayuki; Ohnishi, Makoto; Kura, Fumiaki

2012-01-01

153

Structure of natural draft cooling towers, 1  

International Nuclear Information System (INIS)

Thousands of natural draft cooling towers have been utilized, in Europe and America, as cooling systems of power plants or as countermeasures against thermal polution. Recently in Japan, demands for cooling tower systems have been increasing remarkably with the construction of large power plants and the legislation of environmental regulations. In view of the severe natural conditions in Japan such as strong wind and seismic loadings, etc., the establishment of the optimum design and construction method is essential for the building of safe and economical towers. In order to establish a comprehensive plan of a power plant cooling system of the appropriate structural type, the authors have made researches and experiments on design conditions, static and dynamic analyses, and comparative studies of various structural types such as reinforced concrete thin-shell structures, steel framed structures and composite shell segment structures, based on the investigation results of towers in Europe and America. These results are presented in three reports, the 1st of which concerns cooling tower shells as are hereinafter described. (auth.)

154

Response of cooling towers to wind loads  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with the study of two cooling towers of 122 m and 200 m high above ground level. These cooling towers have been analysed for wind loads using ANSYS software by assuming fixity at the shell base. The wind loads on these cooling towers have been calculated in the form of pressures by using the circumferentially distributed design wind pressure coefficients as given in IS: 11504 - 1985 code [1] along with the design wind pressures at different levels as per IS:875 (Part 3 - 1987 code [2]. The analysis has been carried out using 8-noded shell element (SHELL 93 with 5 degrees of freedom per node. The results of the analysis include membrane forces, viz., meridional force (Nf and hoop force (Nq, and bending moments, viz., meridional moment (Mf and hoop moment (Mq. The vertical distribution of membrane forces and bending moments along 0o and 70o meridians and the circumferential distributions at base, throat and top levels have been studied for both the cooling towers. For circumferential distribution, non-dimensional values have been obtained by normalizing the membrane forces and bending moments using the reference values at 0o meridian. Similarly, the reference values at the base have been used for vertical distribution. These non-dimensional curves for both the cooling towers have been compared in the present study for the feasibility of any generalisation.

G. Murali

2012-01-01

155

Wet/dry cooling tower and method  

Science.gov (United States)

A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

Glicksman, Leon R. (Lynnfield, MA); Rohsenow, Warren R. (Waban, MA)

1981-01-01

156

Improvement of coal focus and cooling towers of COFRENTES NPP  

International Nuclear Information System (INIS)

Cofrentes Nuclear Power Plant is performing a improving program of its cooling towers based on the filling revamping and cooling water circuit improvement. Furthermore, and as consequence of the acquired experience on cooling towers due to the mentioned program, Cofrentes NPP has decided to follow up with this project from a different point of view based on the thermal-hydraulic optimization of the cooling process inside the towers. This program, which is going to be carried out by Cofrentes NPP, Iberinco and Energy Planning and Power Generation (EPPG) provides an improvement on the thermal profile and of the draught inside the cooling towers by improving the water distribution in the towers active area. In order to perform such a program is needed to fulfill a test program to assure a guaranteed performance gain. In this way, Iberinco is developing a test procedure which improves the results which are obtained with the present standards used commonly by the industry. As a consequence of this program, Cofrentes is expecting to obtain a gain of 5 to 8 MWe with a revenue period of 4 to 5 months, results validated in another foreigner Plant which have developed a similar program. (Author)

157

Process integration of complex cooling water systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cooling water systems are generally designed with a set of heat exchangers arranged in parallel. This arrangement results in higher cooling water flowrate and low cooling water return temperature thus reducing cooling tower efficiency. Previous research on cooling water systems has focused mainly on heat exchanger network thus excluding the interaction between heat exchanger network and the cooling towers. The studies completed on cooling water system in which the interactio...

Gololo, Khunedi Vincent

2011-01-01

158

Sensitivity Studies of a Low Temperature Low Approach Direct Cooling Tower for Building Radiant Cooling Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent interest in cooling towers as a mechanism for producing chilled water, together with the evolution of radiant cooling, have prompted a review of evaporative cooling in temperate maritime climates. The thermal efficiency of such systems is a key parameter, as a measure of the degree to which the system has succeeded in exploiting the cooling potential of the ambient air. The feasibility of this concept depends largely however, on achieving low approach water temperatures within an appro...

Nasrabadi, Mehdi; Finn, Donal; Costelloe, Ben

2012-01-01

159

The water-saving and environmentally-minded utilization of waste heat as a substitute for cooling towers-Agrotherm  

International Nuclear Information System (INIS)

Since 1976 the conditions for the utilization of waste heat from power plants in agriculture has been investigated in different test plants in the F.R. of Germany. The system 'Agrotherm' is to substitute traditional cooling towers by closed underground pipe networks. The various investigations showed an overall increase of yield and premature harvest on acreages which had been heated by such pipe networks. The reactions of the various agricultures differ very much, so that a careful choice of sorts is necessary. Possibly considerable infestations of diseases must be expected. The article gives a summary of the most important results gained from the test plants. (KH)

160

Energy savings: SCAM a new type of cooling tower  

International Nuclear Information System (INIS)

Counter current natural draft cooling towers equipped with the device for cold water recovery and the adapted hydraulic circuit studied by CEM- (Compagnie Electro-Mecanique) SCAM system lead to a decrease in pumping energy. For a 1300 MW nuclear power plant energy saved is around 6 MWe, at the cost of energy in France in 1982 saving is F 4 500 000 which compensate for higher investment. They will be used in Golfech power plant; with a high of 178.5 m they will by the highest cooling towers in the world

 
 
 
 
161

Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems.  

Science.gov (United States)

The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, and a long-term study (3 months) to observe the ecological dynamics with repeated introduction of the test strains. An additional set of batch experiments (6 days) was carried out to evaluate the adhesion of each strain to steel surfaces under similar conditions to those found in the cooling tower experiments. Substantial differences were observed in the microbial communities that developed in the batch systems and cooling towers. P. aeruginosa showed a low degree of adherence to steel surfaces both in batch and in the cooling towers, but grew much faster than K. pneumoniae and Flavobacterium in mixed-species biofilms and ultimately became the dominant organism in the closed batch systems. However, the low degree of adherence caused P. aeruginosa to be rapidly washed out of the open cooling tower systems, and Flavobacterium became the dominant microorganism in the cooling towers in both the short-term and long-term experiments. These results indicate that adhesion, retention and growth on solid surfaces play important roles in the bacterial community that develops in cooling tower systems. PMID:19177226

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron

2009-01-01

162

FIELD INVESTIGATIONS OF MECHANICAL DRAFT COOLING TOWER PLUMES  

Science.gov (United States)

Tethered Kitoon (small blimp) sampling techniques were devised to measure the distribution of temperature and humidity in the invisible portion of power plant cooling tower plumes from both single cell and multiple cell cooling towers under several conditions. These measurements,...

163

Indiana State University Graduates to Advanced Plastic Cooling Towers  

Science.gov (United States)

Perhaps more than many other industries, today's universities and colleges are beset by dramatically rising costs on every front. One of the areas where overhead can be contained or reduced is in the operation of the chilled water systems that support air conditioning throughout college campuses, specifically the cooling towers. Like many…

Sullivan, Ed

2012-01-01

164

A study of a desuperheater heat recovery system complete with a reversibly used water cooling tower (RUWCT) for hot water supply  

Science.gov (United States)

Recovering heat rejected from the condenser in a refrigeration system to generate service hot water for buildings is commonly seen in both tropics and subtropics. This study included a critical literature review on heat recovery from air-conditioning/refrigeration systems, with particular emphasis on the direct condenser heat recovery and its related mathematical simulation models. The review identified many applications of desuperheaters to small-scaled residential air-conditioning or heat pump units. The heat and mass transfer characteristics of a RUWCT have been studied in detail, which is based on the theory of direct contact heat and mass transfer between moist air and water. The thesis reports on the differences in the heat and mass transfer process that takes place in a RUWCT, a standard water cooling tower and a spray room. A corrective factor that accounts for the change of chilled water mass flow rate is incorporated into the theoretical analysis of a RUWCT. The algorithms developed from the theoretical analysis are capable of predicting the heat exchange capacity of a RUWCT at any operating conditions. This theoretical analysis is the first of its kind. Extensive field experimental work on the heat and mass transfer characteristics of a RUWCT has been carried out in a hotel building in Haikou, Hainan province of China, where the RUWCT is installed. Results from the experimental work indicate that the theoretical analysis can represent the heat and mass transfer characteristics in a RUWCT with an acceptable accuracy. A numerical analysis for a RUWCT is undertaken to determine both air and water states at intermediate horizontal sections along the tower height. Field experimental data confirm that the predicted air and water conditions at the tower inlet and outlet are of acceptable accuracy. A steady-state mathematical model is developed to simulate the operational performance of a water chiller plant complete with a desuperheater heat recovery system and a RUWCT. This model will be useful in future studies on the optimum design of a water chiller complete with a desuperheater and a RUWCT for heat recovery. (Abstract shortened by UMI.)

Tan, Kunxiong

165

Gasifier wastewater treatment: Phase I cooling tower assessment  

Energy Technology Data Exchange (ETDEWEB)

The principle goal of the gasification research at UNDERC is to develop environmental data on the treatability of wastewaters from the fixed-bed gasification of lignite. Research activities are focused around the cooling tower, where the reuse of treated gasification wastewaters has not been demonstrated in this country. The objective of Phase I cooling tower testing was to evaluate the effectiveness of using minimally treated wastewater (solvent extracted and steam stripped - referred to as stripped gas liquor) as makeup to a cooling tower. Ammonia, alkalinity, phenol, and other non-hydantoin organics were removed from the cooling water by stripping and/or biological degradation. Foaming of the circulating water will be a problem using SGL as makeup and foaming control will be required. The SGL feed cooling system supported a high level of biological activity (1 to 10 million/ml). Pseudomonas aeruginosa was identified as the predominant specie in the system. Severe fouling can be expected for all carbon steel surfaces. Fouling of stainless steel was not a major problem. General corrosion rates of 10 to 24 mils/yr were measured for carbon steel in various parts of the system. Carbon steel heat exchanger tube analysis indicated pitting corrosion penetration rates of 20 to 125 mils/yr under deposits. Computer analysis also indicated a strong potential for scaling from calcium carbonate precipitation. Results from this study indicate that the use of stripped gas liquor similar to that produced by the UNDERC pilot gasifier as cooling tower makeup is limited by a number of potentially serious operating problems. This water could be used for cooling tower makeup only after additional treatment or possibly with the use of biocides, corrosion inhibitors, and other control methods. 12 references, 6 figures, 7 tables. (DMC)

Mann, M.D.; Willson, W.G.; Hendrikson, J.G.; Winton, S.L.

1984-01-01

166

40 CFR 63.1329 - Process contact cooling towers provisions.  

Science.gov (United States)

...is not sent to process contact cooling towers. ...concentration in the process contact cooling tower at or...are sent to the process contact cooling tower. ...(i) At least one sample per operating day shall...be measured during the initial 14-day...

2010-07-01

167

A New Algorithm for Optimum Design of Mechanical Draft Wet Cooling Towers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study describes the designing of a thermally and economically optimum mechanical draft counter-flow wet cooling tower. The design model allows the use of a variety of packing materials in the cooling tower toward optimizing heat transfer. The design model incorporated the cooling tower factors to achieve the optimum design. The main factors included: the diameter of the water droplets, the liquid to gas mass ratio, the height of rain zone, packing zone and spray zone, the ai...

Ataei, A.; Panjeshahi, M. H.; Gharaie, M.

2009-01-01

168

Dynamic analysis of hyperbolic cooling towers  

International Nuclear Information System (INIS)

The methodology of analysis and the design criteria of a cooling tower as related to the wind and earthquake loads are reviewed based on the current state of the art for the two types of load. Recent development of the dynamic analysis for wind and earthquake loadings is discussed. Since the meridional tension is highly sensitive to the wind and earthquake forces, it is worthwhile to analyze the tower using the rational approach. The wind and earthquake loadings should be defined with great care. (Author)

169

Natural draft dry cooling tower modelling  

Science.gov (United States)

Predictions based on a numerical simulation of a natural draft dry cooling tower (NDDCT) has been compared with those obtained theoretically and experimentally. Experiments are conducted in a lab-scale NDDCT and are validated with a three-dimensional numerical simulation of the flow in and around the heat exchangers, which is modelled as a porous medium. Both vertical and horizontal arrangements of the heat exchangers are examined. The experimental, numerical and theoretical approaches lead to very close prediction for the air velocity and temperature at the exit of the cooling tower. Results of this study are expected to be useful for future work on the development of air-cooled condensers for geothermal power plants in Australia.

Tanimizu, K.; Hooman, K.

2013-02-01

170

Evaluation of Cooling Tower Performance RSG-GAS Reactor Using One Line Cooling System  

International Nuclear Information System (INIS)

Utilization of the reactor operation must be done as optimal as possible, so that reactor operation needed efficiently. Reactor power needed in the operation continuously maximum only 15 MW, in this case can be anticipated by doing only using one line cooling system from two line cooling system is available. The consequences by using one line cooling system, it will be impact among performance of cooling tower, for that it is needed research about this case. The research of Multipurpose Reactor GA. Siwabessy's cooling tower when the reactor operator by one line cooling system conducted using the data of operation at 10 MW. The results of calculation showed that for design condition, the ratio of water flow rate to air (L/G) is 1.52, and number transfer unit (NTU) is 0.348. For experiment condition, it is achieved the average of L/G and NTU are 1.37 and 0.342 respectively. The performance value of cooling tower from experiment condition is 91%. That value is greater than feasible value for operation capability cooling tower from acceptable test procedure for industrial cooling tower namely 80%. (author)

171

Cooling towers, the overlooked energy profits generating center  

International Nuclear Information System (INIS)

What is the effect of 0.6C (1F) temperature rise across turbines, compressors, or evaporators? Enthalpy charts indicate for every 0.6C (1F) hotter water off the cooling tower will require an additional 2 1/2 % more energy cost. Therefore, running 2.2C (4F) warmer due to substandard cooling towers could result in a 10% penalty for overcoming high heads and temperatures. If it costs $1,250,000.00 a year to operate the system, $125,000.00 is the energy penalty for hotter water. This paper will investigate extra fuel costs involved in maintaining design electric production with cooling water 0.6C (1F) to 3C (5.5F) hotter than design.design

172

Design problems of large wet cooling towers  

International Nuclear Information System (INIS)

This article aims to indicate the situation which initiated the 'investigations into a natural-draught wet cooling tower' from the VDI progress report 15/5. At the time, the electricity utilities were surprised by the condition, in connection with the building of new power plants on the Rhine, to provide river-independent cooling systems. This condition has not merely enlarged the site criteria catalogue extensively, but also demanded the introduction of a new cooling technology on this scale in the southern regions of the Federal Republic of Germany. (orig./LH)

173

Modeling of existing cooling towers in ASPEN PLUS using an equilibrium stage method  

International Nuclear Information System (INIS)

Highlights: ? Simulation of cooling tower performance under different operating conditions. ? Cooling tower performance is simulated using ASPEN PLUS. ? Levenberg–Marquardt method used to adjust model parameters. ? Air and water outlet temperatures are in good accordance with experimental data. - Abstract: Simulation of cooling tower performance considering operating conditions away from design is typically based on the geometrical parameters provided by the cooling tower vendor, which are often unavailable or outdated. In this paper a different approach for cooling tower modeling based on equilibrium stages and Murphree efficiencies to describe heat and mass transfer is presented. This approach is validated with published data and with data collected from an industrial application. Cooling tower performance is simulated using ASPEN PLUS. Murphree stage efficiency values for the process simulator model were optimized by minimizing the squared difference between the experimental and calculated data using the Levenberg–Marquardt method. The minimization algorithm was implemented in Microsoft Excel with Visual Basic for Applications, integrated with the process simulator (ASPEN PLUS) using Aspen Simulation Workbook. The simulated cooling tower air and water outlet temperatures are in good accordance with experimental data when applying only the outlet water temperature to calibrate the model. The methodology is accurate for simulating cooling towers at differating cooling towers at different operational conditions.

174

A systemic approach for optimal cooling tower operation  

International Nuclear Information System (INIS)

The thermal performance of a cooling tower and its cooling water system is critical for industrial plants, and small deviations from the design conditions may cause severe instability in the operation and economics of the process. External disturbances such as variation in the thermal demand of the process or oscillations in atmospheric conditions may be suppressed in multiple ways. Nevertheless, such alternatives are hardly ever implemented in the industrial operation due to the poor coordination between the utility and process sectors. The complexity of the operation increases because of the strong interaction among the process variables. In the present work, an integrated model for the minimization of the operating costs of a cooling water system is developed. The system is composed of a cooling tower as well as a network of heat exchangers. After the model is verified, several cases are studied with the objective of determining the optimal operation. It is observed that the most important operational resources to mitigate disturbances in the thermal demand of the process are, in this order: the increase in recycle water flow rate, the increase in air flow rate and finally the forced removal of a portion of the water flow rate that enters the cooling tower with the corresponding make-up flow rate.

175

A New Algorithm for Optimum Design of Mechanical Draft Wet Cooling Towers  

Directory of Open Access Journals (Sweden)

Full Text Available The present study describes the designing of a thermally and economically optimum mechanical draft counter-flow wet cooling tower. The design model allows the use of a variety of packing materials in the cooling tower toward optimizing heat transfer. The design model incorporated the cooling tower factors to achieve the optimum design. The main factors included: the diameter of the water droplets, the liquid to gas mass ratio, the height of rain zone, packing zone and spray zone, the air and water velocity inside the tower and the frontal area. Once the optimum packing type is chosen, a compact cooling tower with low fan power consumption is modelled within the known design variables. The optimization model is validated against a sample problem. The suggested design algorithms of cooling tower are computed using Visual Studio.Net 2003 (C++.

A. Ataei

2009-01-01

176

Effectiveness of bromicide against Legionella pneumophila in a cooling tower  

Energy Technology Data Exchange (ETDEWEB)

Cooling towers are considered to be man-made amplifiers of Legionella. Thus the proper maintenance and choice of biocides is important. The only biocide that has thus far been shown to be effective in field tests is the judicious use of chlorination. Perturbation studies were conducted on an industrial cooling tower shown to contain Legionella, using 1-bromo-3-chloro-5,5-dimethylhydantoin (Bromicide, Great Lakes Chemical Corp.). At the manufacturer's recommended concentrations neither the density nor the activity of Legionella was affected. At concentrations greater than 2.0 ppM free residual, the Bromicide was not effective in reducing Legionella to source water concentrations, nor was it effective in reducing the INT activity of the bacterium in situ. The data indicate that at concentrations up to 2.0 ppM, Bromicide is not effective in these tower studies. 23 references, 3 tables.

Fliermans, C.B.; Harvey, R.S.

1983-01-01

177

European dry cooling tower operating experience  

Energy Technology Data Exchange (ETDEWEB)

Interviews were held with representatives of major plants and equipment manufacturers to obtain current information on operating experience with dry cooling towers in Europe. The report documents the objectives, background, and organizational details of the study, and presents an itemized account of contacts made to obtain information. Plant selection was based on a merit index involving thermal capacity and length of service. A questionnaire was used to organize operational data, when available, into nine major categories of experience. Information was also solicited concerning the use of codes and standards to ensure the achievement of cooling tower performance. Several plant operators provided finned-tube samples for metallographic analysis. Additionally, information on both operating experience and developing technology was supplied by European technical societies and research establishments. Information obtained from these contacts provides an updated and representative sample of European experience with dry cooling towers, which supplements some of the detailed reviews already available in the literature. In addition, the study presents categorized operating experience with installations which have not been reviewed so extensively, but nevertheless, have significant operational histories when ranked by the merit index. The contacts and interviews reported in the survey occurred between late March and October 1975. The study was motivated by the expressed interest of U.S. utility industry representatives who expect European experience to provide a basis of confidence that dry cooling is a reliable technology, applicable when necessary, to U.S. operating requirements.

DeSteese, J.G.; Simhan, K.

1976-03-01

178

European dry cooling tower operating experience  

International Nuclear Information System (INIS)

Interviews were held with representatives of major plants and equipment manufacturers to obtain current information on operating experience with dry cooling towers in Europe. The report documents the objectives, background, and organizational details of the study, and presents an itemized account of contacts made to obtain information. Plant selection was based on a merit index involving thermal capacity and length of service. A questionnaire was used to organize operational data, when available, into nine major categories of experience. Information was also solicited concerning the use of codes and standards to ensure the achievement of cooling tower performance. Several plant operators provided finned-tube samples for metallographic analysis. Additionally, information on both operating experience and developing technology was supplied by European technical societies and research establishments. Information obtained from these contacts provides an updated and representative sample of European experience with dry cooling towers, which supplements some of the detailed reviews already available in the literature. In addition, the study presents categorized operating experience with installations which have not been reviewed so extensively, but nevertheless, have significant operational histories when ranked by the merit index. The contacts and interviews reported in the survey occurred between late March and October 1975. The study was motivated by the expressed interesudy was motivated by the expressed interest of U.S. utility industry representatives who expect European experience to provide a basis of confidence that dry cooling is a reliable technology, applicable when necessary, to U.S. operating requirements

179

Laboratory simulations of interactive plumes from mechanical draft cooling towers  

International Nuclear Information System (INIS)

In connection with studies being conducted under the Meteorological Effects of Thermal Energy Releases (METER) Program, Pacific Northwest Laboratory (PNL) has been simulating discharges from physical models of mechanical draft cooling towers to determine the impact of various conditions in cooling tower plume mixing and trajectory. Analysis of the data suggests that siting cooling towers should be based on ambient wind history, plume dynamics, and tower operating conditions, and possibly on site terrain

180

Recent developments of cooling tower design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Natural draught cooling towers (NDCT) are the characterizing landmarks of power stations. They contribute both to an efficient energy output and to a careful balance with our environment. In the last decade the building of new power plants stagnated all over the world. Nowadays the German power suppliers have started an extensive renewal program, where old units will be replaced by new ones, which will be much cleaner and more efficient. Besides innovative boiler techniques the sustainable an...

Harte, Reinhard; Wittek, Udo

2009-01-01

 
 
 
 
181

Susceptibility of Legionella pneumophila to three cooling tower microbicides.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Investigation of epidemic outbreaks of Legionnaires disease by Center for Disease Control personnel has resulted in the isolation of Legionella pneumophila from water in the air-conditioning cooling towers or evaporative condensers at the site of the outbreak. It is suspected that improperly maintained open, recirculating water systems may play a role in the growth and dissemination of this pathogen. The objective of this study was to determine the antimicrobial activity of three chemically d...

Grace, R. D.; Dewar, N. E.; Barnes, W. G.; Hodges, G. R.

1981-01-01

182

Interception and retention of simulated cooling tower drift by vegetation  

International Nuclear Information System (INIS)

A key issue concerning environmental impacts from cooling tower operation is the interception of drift by vegetation and the efficiency of plants in retaining the residue scavenged from the atmosphere. Chromated drift water, typical of the cooling towers of the Department of Energy's uranium enrichment facilities at Oak Ridge, Tennessee, was prepared using radio-labelled chromium. A portable aerosol generator was used to produce a spectrum of droplets with diameters (100 to 1300 ?) characteristic of cooling towers using state-of-the-art drift eliminators. Efficiency of interception by foliage varied according to leaf morphology with yellow poplar seedlings intercepting 72% of the deposition mass in contrast to 45% by loblolly pine and 24% by fescue grass. Retention patterns of intercepted deposition consisted of a short-time component (0 to 3 days) and a long-time component (3 to 63 days). Retention times, estimated from the regression equation of the long component, indicated that drift contamination from any deposition event may persist from between 8 and 12 weeks. In field situations adjacent to cooling towers, the average annual concentration of drift on vegetation at any distance remains relatively constant, with losses from weathering being compensated by chronic deposition

183

Corrosion control studies in a mini cooling tower  

International Nuclear Information System (INIS)

Generally, raw water is used for cooling the condensers in packaged air conditioning (AC) units installed in separate buildings. These AC units and their cooling water systems are operated on as-and-when required basis. The cooling water remains untreated generally. The Fast Breeder Test Reactor (FBTR) at Kalpakkam, TamiInadu, India is a 40 MWt sodium cooled, (uranium and plutonium) mixed carbide fuelled nuclear test reactor. In FBTR, four freon-based packaged AC units having 40 TR capacities with cooling water system have been installed in Annexe Building. Palar river water serves as the make-up to the system. The heat extracted from condensers is rejected in natural draft cooling tower. Initially, algae fouling and increased corrosion attacks were observed in the system. Sodium hypo chlorite dosing reduced the algae fouling considerably. Corrosion monitoring program was initiated with installation of corrosion monitoring set up. Inhibitors and dispersants like hydroxy ethylidene diphosphonic acid, sodium hexa meta phosphate, sodium dodecyl sulphate, ortho phosphoric acid and poly acrylic acid were used. It has been observed that minimum corrosion rate of 5 mpy could be obtained with 20 ppm of Hydroxy Ethylidene Diphosphonic Acid (HEDP) and 20 ppm of poly acrylic acid as against 9 mpy for the untreated water. This paper describes the problems associated with irregular operation of cooling water systems in corrosion control and experience gained in control of bio fould experience gained in control of bio fouling and corrosion in cooling water system installed in packaged AC units having natural draft cooling tower. (author)

184

Measurements on cooling tower plumes. Pt. 3  

International Nuclear Information System (INIS)

In this paper an extended field experiment is described in which cooling tower plumes were investigated by means of three-dimensional in situ measurements. The goal of this program was to obtain input data for numerical models of cooling tower plumes. Data for testing or developing assumptions for sub-grid parametrizations were of special interest. Utilizing modern systems for high-resolution aerology and small aircraft, four measuring campaigns were conducted: two campaigns (1974) at the cooling towers of the RWE power station at Neurath and also two (1975) at the single cooling tower of the RWE power station at Meppen. Because of the broad spectrum of weather situations, it can be assumed that the results are representative with regard to the interrelationship between the structure of cooling tower plumes and the large-scale meteorological situation. A large number of flights with a powered glider ASK 16 (more than 100 flight hours) crossing the plumes on orthogonal tracks was performed. All flights showed that the plume could be identified up to large downwind distances by discontinuous jumps of temperature and vapour pressure. Therefore a definite geometry of the plume could always be defined. In all cross sections a vertical circulation could be observed. At the plumes boundaries, which could be defined by the mentioned jumps of temperature and vapour pressure, a maximum of downward vertical motion was observed in most cases. Entrainment along the boundary of a cross section seems to be very small, except at the lower part of the plume. There, the mass entrainment is maximum and is responsible for plume rise as well as for enlargement of the cross section. The visible part of the plume (cloud) was only a small fraction of the whole plume. The discontinuities of temperature and vapour pressure show that the plume fills the space below the visible plume down to the ground. However, all effects decrease rapidly towards the ground. It turned out that high-resolution aerology is necessary in order to explain the structure and behaviour of such plumes. This is especially the case in investigations regarding the dynamic break-through of temperature inversions. Such cases were observed quite frequently under various meteorological conditions and are described in this paper. (orig.)

185

Investigations of combined used of cooling ponds with cooling towers or spraying systems  

International Nuclear Information System (INIS)

Based on a brief analysis of the methods of investigating cooling ponds, spraying systems and cooling towers, a conclusion is made that the direct modelling of the combined use of cooling systems listed cannot be realized. An approach to scale modelling of cooling ponds is proposed enabling all problems posed by the combined use of coolers to be solved. Emphasized is the importance of a proper choice of a scheme of including a cooler in a general water circulation system of thermal and nuclear power plants. A sequence of selecting a cooling tower of the type and spraying system of the size ensuring the specified temperature regime in a water circulation system is exemplified by the water system of the Ghorasal thermal power plant in Bangladesh

186

Cooling towers for combined cycles: Design philosophy, performance testing, and operating problems  

Science.gov (United States)

The characteristics and parameters affecting the choice of a type of cooling tower and its installation in the circuit of a combined cycle are discussed. The different possibilities of water circuits that are encountered are defined. Two modes of exchange and two types of fill are discussed. The various types of wet towers are described and their advantages and disadvantages considered. Factors affecting the selection of a cooling tower include: cost of energy versus cost of tower; performances; water availability and quality; emissions (water, noise, air, and vapor); site locations; and operating conditions.

Bauthier, J.

187

Performance prediction of a cooling tower using artificial neural network  

International Nuclear Information System (INIS)

This paper describes an application of artificial neural networks (ANNs) to predict the performance of a cooling tower under a broad range of operating conditions. In order to gather data for training and testing the proposed ANN model, an experimental counter flow cooling tower was operated at steady state conditions while varying the dry bulb temperature and relative humidity of the air entering the tower and the temperature of the incoming hot water along with the flow rates of the air and water streams. Utilizing some of the experimental data for training, an ANN model based on a standard back propagation algorithm was developed. The model was used for predicting various performance parameters of the system, namely the heat rejection rate at the tower, the rate of water evaporated into the air stream, the temperature of the outgoing water stream and the dry bulb temperature and relative humidity of the outgoing air stream. The performances of the ANN predictions were tested using experimental data not employed in the training process. The predictions usually agreed well with the experimental values with correlation coefficients in the range of 0.975-0.994, mean relative errors in the range of 0.89-4.64% and very low root mean square errors. Furthermore, the ANN yielded agreeable results when it was used for predicting the system performance outside the range of the experiments. The results show that the ANN approach can be applied successfully and can provide high applied successfully and can provide high accuracy and reliability for predicting the performance of cooling towers

188

Analysis of the evaporative towers cooling system of a coal-fired power plant  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents a theoretical analysis of the cooling system of a 110 MW coal-fired power plant located in central Serbia, where eight evaporative towers cool down the plant. An updated research on the evaporative tower cooling system has been carried out to show the theoretical analysis of the tower heat and mass balance, taking into account the sensible and latent heat exchanged during the processes which occur inside these towers. Power plants which are using wet cooling towers for cooling condenser cooling water have higher design temperature of cooling water, thus the designed condensing pressure is higher compared to plants with a once-through cooling system. Daily and seasonal changes further deteriorate energy efficiency of these plants, so it can be concluded that these plants have up to 5% less efficiency compared to systems with once-through cooling. The whole analysis permitted to evaluate the optimal conditions, as far as the operation of the towers is concerned, and to suggest an improvement of the plant. Since plant energy efficiency improvement has become a quite common issue today, the evaluation of the cooling system operation was conducted under the hypothesis of an increase in the plant overall energy efficiency due to low cost improvement in cooling tower system.

Lakovi? Mirjana S.

2012-01-01

189

Investigation of Natural Draft Cooling Tower Performance Using Neural Network  

Science.gov (United States)

In the present work Artificial Neural Network (ANN) technique is used to investigate the performance of Natural Draft Wet Cooling Tower (NDWCT). Many factors are affected the rang, approach, pressure drop, and effectiveness of the cooling tower which are; fill type, water flow rate, air flow rate, inlet water temperature, wet bulb temperature of air, and nozzle hole diameter. Experimental data included the effects of these factors are used to train the network using Back Propagation (BP) algorithm. The network included seven input variables (Twi, hfill, mw, Taiwb, Taidb, vlow, vup) and five output variables (ma, Taowb, Two, ?p, ?) while hidden layer is different for each case. Network results compared with experimental results and good agreement was observed between the experimental and theoretical results.

Mahdi, Qasim S.; Saleh, Saad M.; Khalaf, Basima S.

190

Hospital-acquired legionellosis originating from a cooling tower during a period of thermal inversion.  

Science.gov (United States)

A case of hospital-acquired legionellosis occurred in a 75-year-old male patient who underwent surgery due to malignant melanoma. Legionellosis was proven by culture of Legionella pneumophila serogroup 1 from bronchoalveolar lavage (BAL) fluid. Being a chronic smoker the patient used to visit the sickroom balcony that was located about 90 m to the west of a hospital cooling tower. Routine cooling tower water samples drawn during the presumed incubation period revealed 1.0x10(4) CFU/100 ml (L. pneumophila serogroup 1). One of three isolates from the cooling tower water matched the patient's isolate by monoclonal antibody (mab)- and genotyping (sequence-based typing). Horizontal transport of cooling tower aerosols probably was favoured by meteorological conditions with thermal inversion. The case report stresses the importance of routine maintenance and microbiological control of hospital cooling towers. PMID:17870669

Engelhart, Steffen; Pleischl, Stefan; Lück, Christian; Marklein, Günter; Fischnaller, Edith; Martin, Sybille; Simon, Arne; Exner, Martin

2008-07-01

191

Thermal and Chemical Analysis of Fouling Phenomenon in Condensers for Cooling Tower Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Brazed plate heat exchanges (BPHEs) and tube-in-tube heat exchangers (TTHEs) are commonly used in the refrigeration, air conditioning, and food industry as refrigerant-to-water condensers, in which refrigerant rejects heat to water circulating in cooling tower loops. These heat exchangers often suffer from severe fouling issues because as the water in the cooling tower evaporates, the mineral concentration in the remaining water increases. Once the solubility limits are reached, the minerals ...

Wu, Xiaoxiao; Cremaschi, Lorenzo

2012-01-01

192

Study on Characteristics of Special Turbine in Hydrodynamic Cooling Tower  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Today a special type of hydraulic turbine is used to replace electromotor to drive the fan in hydrodynamic cooling tower. This is a brand new turbine application. At present, systematic researching about the special turbine has still not been seen. The energy consumption of the electromotor is saved entirely because the power source comes from the surplus energy of circulating water system. But the special turbine works in a series of pressure flow system, its flow characteristic, working cha...

Li Yanpin; Zhang Lanjin; Chen Dexin

2012-01-01

193

Preliminary design of dry cooling tower for the closed cycle gas turbine HTGR  

International Nuclear Information System (INIS)

The effects of air approach velocity, capacity rates of air and water mediums, and number of heat exchanger cross flow passes on tower and heat exchanger dimensions are studied. Optimum tower designs are achieved with three cross flow passes for the heat exchanger, resulting in minimization of tower height, heat exchanger surface area and circulating water pumping power. The 1200 MW(e) plant can be cooled by a single tower design. In comparison, the fossil-fired or HTGR steam plants of the same output need three towers. 16 refs

194

Cooling tower shell and mechanical or draft cooling tower with a such shell  

International Nuclear Information System (INIS)

The shell is for thermal power plants cooling towers having heat exchange surfaces inside the tower. The vertical is such that the hydraulic diameter D in each horizontal section, at a level z above a reference section of which hydraulic diameter is Do is between once and 1.15 time the value given by the formula: Do(1+(2??gz/?Vo2))O,25 + 2?z in which Vo is the vertical flow rate through the reference section; ? is the hot air density; ?? is the density difference of the hot air between the outside and the inside of the shell; ? is an adjustment parameter without dimension of which value is between 0.09 and 0.13. The present invention ensures the cooling tower to operate nearly at the optimum and the construction cost of the shell is reduced

195

Effect of chlorine and temperature on free-living protozoa in operational man-made water systems (cooling towers and hot sanitary water systems) in Catalonia.  

Science.gov (United States)

In recent decades, free-living protozoa (FLP) have gained prominence as the focus of research studies due to their pathogenicity to humans and their close relationship with the survival and growth of pathogenic amoeba-resisting bacteria. In the present work, we studied the presence of FLP in operational man-made water systems, i.e. cooling towers (CT) and hot sanitary water systems (HSWS), related to a high risk of Legionella spp. outbreaks, as well as the effect of the biocides used, i.e. chlorine in CT and high temperature in HSWS, on FLP. In CT samples, high-chlorine concentrations (7.5?±?1.5 mg chlorine L(-1)) reduced the presence of FLP by 63.8 % compared to samples with low-chlorine concentrations (0.04?±?0.08 mg chlorine L(-1)). Flagellates and amoebae were observed in samples collected with a level of 8 mg chlorine L(-1), which would indicate that some FLP, including the free-living amoeba (FLA) Acanthamoeba spp., are resistant to the discontinuous chlorine disinfection method used in the CT studied. Regarding HSWS samples, the amount of FLP detected in high-temperatures samples (53.1?±?5.7 °C) was 38 % lower than in low-temperature samples (27.8?±?5.8 °C). The effect of high temperature on FLP was chiefly observed in the results obtained by the culture method, in which there was a clear reduction in the presence of FLP at temperatures higher than 50 °C, but not in those obtained by PCR. The findings presented here show that the presence of FLP in operational man-made water systems should be taken into account in future regulations. PMID:25410311

Canals, Oriol; Serrano-Suárez, Alejandra; Salvadó, Humbert; Méndez, Javier; Cervero-Aragó, Sílvia; Ruiz de Porras, Vicenç; Dellundé, Jordi; Araujo, Rosa

2014-11-21

196

Experimental study on the thermal performance of a mechanical cooling tower with different drift eliminators  

International Nuclear Information System (INIS)

Cooling towers are equipment devices commonly used to dissipate heat from power generation units, water-cooled refrigeration, air conditioning and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimize water loss from the system. It is foreseeable that the characteristics of the installed drift eliminators, like their pressure drop, affect the thermal performance of the cooling tower. However, no references regarding this fact have been found in the reviewed bibliography. This paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with different drift eliminators for a wide range of air and water mass flow rates. The data registered in the experimental set-up were employed to obtain correlations of the tower characteristic, which defines the cooling tower's thermal performance. The outlet water temperature predicted by these correlations was compared with the experimentally registered values obtaining a maximum difference of ±3%

197

Natural draft cooling tower with shell disconnected from the substructure  

International Nuclear Information System (INIS)

The aim of this paper is the analysis of results of a research done by Electricite de France, concerning a new type of cooling tower. The traditional structure (i.e. a hyperbolic shell supported by X shaped or diagonal columns) is replaced by two independent structures: the shell, becoming a self-contained structure, the lower rim being stiffened by an annular beam; the substructure, resting on the soil. This new type of cooling tower has an improved thermal performance due to the increase of the area of air entrance. Bearing pads are provided between the lower ring beam of the shell and the substructure. Any differential settlement can be coped with by jacking. The water distribution structure can be laid out so as to benefit from advantages offered by the presence of the stiff ring and columns of the substructure

198

Development of an improved PCR-ICT hybrid assay for direct detection of Legionellae and Legionella pneumophila from cooling tower water specimens.  

Science.gov (United States)

A novelly improved polymerase chian reaction and immunochromatography test (PCR-ICT) hybrid assay comprising traditional multiplex-nested PCR and ICT, (a lateral-flow device) was developed for direct detection of Legionella bacteria from environmental cooling tower samples. The partial 16S rDNA (specific for Legionella spp.) and dnaJ (specific for Legionella pneumophila) genes from Legionella chromosome were first specifically amplified by multiplex-nested PCR, respectively, followed by detection using ICT strip. Reading of results was based on presence or absence of the two test lines on the strips. Presence of test line 1 indicated existence of Legionella spp. specific 16S rDNA and identified Legionella spp. Presence of test line 2 further indicated existence of dnaJ and thus specifically identified L. pneumophila. In contrast, for non-Legionellae bacteria no test line formation was observed. Results of direct detection of Legionella bacteria and L. pneumophila from water tower specimens by this assay showed 100% sensitivity, and 96.6% and 100% specificity, respectively compared with traditional culture, biochemical and serological identification methods. The PCR-ICT hybrid assay does not require sophisticated equipment and was proved to be practically useful in rapid and direct Legionellae detection from environmental water samples. PMID:16713613

Horng, Yu-Tze; Soo, Po-Chi; Shen, Bin-Jon; Hung, Yu-Li; Lo, Kai-Yin; Su, Hsun-Pi; Wei, Jun-Rong; Hsieh, Shang-Chen; Hsueh, Po-Ren; Lai, Hsin-Chih

2006-06-01

199

Measurements at cooling tower plumes. Part 3. Three-dimensional measurements at cooling tower plumes  

International Nuclear Information System (INIS)

An extended field experiment is described in which cooling tower plumes were studied by means of three-dimensional in situ measurements. The goal was to obtain input data for numerical models of cooling tower plumes. Of special interest were data for testing or developing assumptions for sub-grid parametrizations. Utilizing modern systems for high-resolution aerology and small aircraft, four measuring campaigns were conducted: two campaigns (1974) at the cooling towers of the RWE power station Neurath and also two (1975) at the single cooling tower of the RWE power station Meppen. Because of the broad spectrum of weather situations it can be assumed that the results are representative with regard to the interrelationship between structure of cooling tower plume and large-scale meteorological situation. A large number of flights with a powered glider crossing the plumes on orthogonal tracks was performed. All flights showed that the plume could be identified up to large downwind distances by discontinuous jumps of temperature and vapor pressure. Therefore, a definite geometry of the plume could always be defined. In all cross sections a vertical circulation could be observed. At the boundary, which could be defined by the mentioned jumps of temperature and vapor pressure, a maximum of downward vertical motion could be observed in most cases. Entrainment along the boundary of a cross section seems to be very small, except at the lower part of the plume. There, the mass entrainment is maximum and is responsible for plume rise as well as for enlargement of the cross section. The visible part of the plume (cloud) was only a small fraction of the whole plume. High-resolution aerology is necessary in order to explain the structure and behavior of such plumes. This is especially the case in investigations regarding the dynamic break-through of temperature inversions. Such cases were observed frequently under various meteorological conditions and are described

200

Investigation of emissions of harmful substances in the cooling tower of the final coke oven gas cooling cycle  

International Nuclear Information System (INIS)

It is known that the cooling tower of the open coke oven gas cooling cycle is the main source of emissions to the atmosphere of hydrogen cyanide. Desorption of volatile harmful substances in cooling tower depends on a large number of processing parameters and the compositions of the circulating water. The authors conducted a study of desorption of volatile components and a model of adequate scale of the final gas cooling cycle on an experimental industrial unit with a gas output of about 500 m3/hr. The unit was built at the Cherepovets Integrated Iron and Steel Works. In includes a cooling tower made of tubes 100 mm in diameter with a total height of about 5,100 mm. The volume of the lower part is 2.12 m3. Preliminary experimental evaluation of operation of the cooling tower according to the material and heat balances showed that it models operation of an industrial cooling tower quite well. Emissions of harmful substances in the cooling tower were determined by analyzing the circulating water and air before and after the cooling tower. Averaged samples for specified times were collected and the process parameters were simultaneously recorded (flow rates and temperatures of water and air), as well as the relative humidity and air pressure. Analysis of possible errors and the actual agreement of the determinations of the content of substances in air and water showed that evaluation of desorption of volatile components according to water analyses ie components according to water analyses is more reliable (this conclusion is especially valid for industrial cooling towers). Results are described

 
 
 
 
201

Natural frequencies of cooling tower shells  

Science.gov (United States)

Approximate explicit formulae are presented for (i) the fundamental natural frequency of vibration of a uniform hyperboloidal cooling tower shell mounted on a rigid base, and (ii) for the circumferential wavenumber associated with fundamental mode. These formulae agree well with results previously obtained by finite element computation and they may be adapted readily for use with cooling tower shells mounted on non-rigid supports. The simplicity of the formulae is a consequence of various approximations which are made in the analysis. "Shallow shell" equations are used, and it is assumed that the dominant structural effects in the shell are longitudinal stretching and circumferential bending. The equations are applied first to the more straightforward case of a cylindrical shell which is clamped at one end and free at the other. The various assumptions are examined systematically, and a wide domain is established in which the resulting formulae for fundamental natural frequency and circumferential wavenumber are valid. The most appropriate dimensionless form of the length of the shell in this domain is ?=Lh1/2/ a3/2, where L is length, h is thickness and a is radius. A simple scheme is presented, with justification, for the adaptation of the results to a shell which is mounted on a non-rigid base. The equations are then applied to a hyperboloidal shell, and the corresponding formulae are obtained. Again the dimensionless group ? is appropriate, but it must now be supplemented by a second parameter which defines the hyperboloidal shape of the shell. Remarks are made concerning the design of ring stiffeners for the upper edge, the sensitivity of the fundamental frequency to small changes in any of the leading dimensions of the tower and cases in which the elastic modulus of the material may be different in different parts of the shell.

Calladine, C. R.

1982-06-01

202

Method and system for simulating heat and mass transfer in cooling towers  

Science.gov (United States)

The present invention is a system and method for simulating the performance of a cooling tower. More precisely, the simulator of the present invention predicts values related to the heat and mass transfer from a liquid (e.g., water) to a gas (e.g., air) when provided with input data related to a cooling tower design. In particular, the simulator accepts input data regarding: (a) cooling tower site environmental characteristics; (b) cooling tower operational characteristics; and (c) geometric characteristics of the packing used to increase the surface area within the cooling tower upon which the heat and mass transfer interactions occur. In providing such performance predictions, the simulator performs computations related to the physics of heat and mass transfer within the packing. Thus, instead of relying solely on trial and error wherein various packing geometries are tested during construction of the cooling tower, the packing geometries for a proposed cooling tower can be simulated for use in selecting a desired packing geometry for the cooling tower.

Bharathan, Desikan (Lakewood, CO); Hassani, A. Vahab (Golden, CO)

1997-01-01

203

Thermal performance upgrade of the Arkansas Nuclear One cooling tower: A ``root cause`` analysis approach  

Energy Technology Data Exchange (ETDEWEB)

The thermal performance efficiency of the natural draft cooling tower at Entergy Operations` 858 MWe Arkansas Nuclear One, Unit 2 was successfully upgraded to 101% of design performance capability in April 1994 as the end result of a unique root-cause analysis of the cooling tower`s long-standing performance deficiencies. Through application of state-of-the-art diagnostic testing methods and computer modeling techniques, Entergy was able to identify and correct air/water maldistribution problems in the 447 foot tall counterflow cooling tower at minimal cost. Entergy estimates that the savings realized, as a result of the 1.2 F reduction in cooling tower outlet water temperature, will pay for the thermal upgrade project in approximately 14 months.

Liffick, G.W. [Entergy Operations, Inc., Russellville, AR (United States); Cooper, J.W. Jr. [John Cooper and Associates, Tampa, FL (United States)

1995-10-01

204

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers  

Science.gov (United States)

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative "dry" cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered.

Abedi-Nik, Farhad; Sabouri-Ghomi, Saeid

2008-07-01

205

Thermal performances investigation of a wet cooling tower  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an experimental investigation of the thermal performances of a forced draft counter flow wet cooling tower filled with an 'VGA' (Vertical Grid Apparatus) type packing. The packing is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test area of 0.0222 m{sup 2} (0.15 m x 0.148 m). This study investigates the effect of the air and water flow rates on the cooling water range as well as the tower characteristic, for different inlet water temperatures. Two operating regimes were observed during the air water contact, a pellicular regime (PR) and a bubble and dispersion regime (BDR). These two regimes can determine the best way to promote the heat transfer. The BDR regime seems to be more efficient than the pellicular regime, as it enables to cool larger water flow rates. The comparison between the obtained results and those found in the literature for other types of packing indicates that this type possesses very interesting thermal performances.

Lemouari, M. [Department of Processes Engineering, Faculty of Sciences and Engineering Sciences, University of Bejaia (Algeria); Boumaza, M. [Department of Chemical Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421 (Saudi Arabia)]. E-mail: boumaza_m@hotmail.com; Mujtaba, I.M. [School of Engineering, Design and Technology, University of Bradford, Bradford (United Kingdom)

2007-04-15

206

Thermal performances investigation of a wet cooling tower  

International Nuclear Information System (INIS)

This paper presents an experimental investigation of the thermal performances of a forced draft counter flow wet cooling tower filled with an 'VGA' (Vertical Grid Apparatus) type packing. The packing is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test area of 0.0222 m2 (0.15 m x 0.148 m). This study investigates the effect of the air and water flow rates on the cooling water range as well as the tower characteristic, for different inlet water temperatures. Two operating regimes were observed during the air water contact, a pellicular regime (PR) and a bubble and dispersion regime (BDR). These two regimes can determine the best way to promote the heat transfer. The BDR regime seems to be more efficient than the pellicular regime, as it enables to cool larger water flow rates. The comparison between the obtained results and those found in the literature for other types of packing indicates that this type possesses very interesting thermal performances

207

ASSESSMENT OF THREE TECHNOLOGIES FOR THE TREATMENT OF COOLING TOWER BLOWDOWN  

Science.gov (United States)

The report gives results of analyses of three methods for treating cooling tower blowdown: vapor compression evaporation (VCE), reverse osmosis (RO), and vertical tube foaming evaporation (VTFE). The two evaporative processes produce pure water (approximately 10 ppm dissolved sol...

208

A study of the life expectancy of cooling towers  

International Nuclear Information System (INIS)

The paper describes the following different tasks of the study whose aim was to extend the life time of cooling towers for French Nuclear Power plants to 40 years. The aging factors specific to cooling towers were measured and analysed with regard to the external surface, the internal surface and inside the concrete. The safety coefficient for buckling was calculated and then the stress analysis of the materials (concrete and steel) was done. A special computer program written for cooling towers was used with a model including the soil stiffness and the supports of the tower. (author)

209

Engineering evaluation of magma cooling-tower demonstration at Nevada Power Company's Sunrise Station  

Science.gov (United States)

The Magma Cooling Tower (MCT) process utilizes a falling film heat exchanger integrated into an induced draft cooling tower to evaporate waste water. A hot water source such as return cooling water provides the energy for evaporation. Water quality control is maintained by removing potential scaling constituents to make concentrations of the waste water possible without scaling heat transfer surfaces. A pilot-scale demonstration test of the MCT process was performed from March 1979 through June 1979 at Nevada Power Company's Sunrise Station in Las Vegas, Nevada. The pilot unit extracted heat from the powerplant cooling system to evaporate cooling tower blowdown. Two water quality control methods were employed: makeup/sidestream softening and fluidized bed crystallization. The 11 week softening mode test was successful.

1980-11-01

210

Improving performance and reducing costs of cooling towers  

International Nuclear Information System (INIS)

Cooling towers represent a significant capital investment at a steam electric power station. In addition, deficiencies in thermal performance can result in major operating penalties of fuel cost, replacement energy, and capacity addition. This paper summarizes two recent EPRI research projects aimed at reducing thermal performance deficiencies and decreasing installed costs of evaporative cooling towers. First, EPRI Research Project 2113, Cooling Tower Performance Prediction and Improvement, is summarized. This project has resulted in published data sets on the measured thermal performance characteristics of a variety of cooling tower packings, computer codes to predict tower performance, and computer code validation through large-scale tower performance measurements. Principal results are contained in an EPRIGEMS software module, Cooling Tower Advisor. This PC- based software contains a tutorial plus codes to predict tower thermal performance, arranged in a user-friendly format. The second EPRI effort, Research Project 2819-10/11, Fabric Structures for Power Plant Applications, has resulted in designs and costs of large structures with shells constructed of recently-developed fabrics. Primary power plant applications for such structures are the shells of natural draft cooling towers and coal-pile covers. Fabric structures offer low initial cost, acceptable life, and seismic superiority, among other advantages. Detailed conceptual designs and installed cost data are rtual designs and installed cost data are reviewed. 8 refs., 9 figs., 3 tabs

211

Hydroaerothermal investigations conducted in the USSR to justify the construction of large cooling towers  

International Nuclear Information System (INIS)

The multi-purpose task of improving water cooling systems of thermal and nuclear power plants is aimed at the development of efficient designs of cooling towers and other types of industrial coolers which call for comprehensive scientific justification. Cooling towers of 60-70 thou m3/h capacity with a chimney height of 130 m and those of 80-100 thou m3/h capacity with a chimney height of 150 m were developed. For circulating water systems of large power plants the design of a counterflow chimney cooling tower of 180 thou m3/h capacity has been recently developed. At present the work is being conducted on developing a new three-cell cooling tower featuring high reliability, operational flexibility and cost-effectiveness of the design. This cooling tower, besides having higher operating reliability than the conventional one of circular shape, can ensure the commissioning, current repairs and overhauls of water cooling arrangements in a cell-wise sequence, i.e. without shutting down the power generating units. Laboratory and field investigations of the spray-type cooling towers having no packing (fill), studies on heat and mass exchanges processes, aerodynamics of droplet flows and new designs of sprayers made it possible to come to a conclusion that their cooling capacity can be substantially increased and brought up to the level of the cooling towers with film packings. The pilot cooling towers were designed according to the counterflo were designed according to the counterflow, crossflow and cross-counterflow schemes. The basic investigation method remains to be the experimental one. On the test rigs and aerodynamic models the heat and mass transfer and aerodynamic resistance coefficients are determined. These studies and subsequent calculations are based on the heat balance equation

212

75 FR 63802 - Action Affecting Export Privileges; Parto Abgardan Cooling Towers Co.  

Science.gov (United States)

...Affecting Export Privileges; Parto Abgardan Cooling Towers Co. Parto Abgardan Cooling Towers Co., P.O. Box 966, Folsom, CA 95763...Denial of Export Privileges of Aqua-Loop Cooling Towers, Co. Applicable to Parto Abgardan...

2010-10-18

213

75 FR 16732 - Action Affecting Export Privileges; Aqua-Loop Cooling Towers, Co.  

Science.gov (United States)

...Export Privileges; Aqua-Loop Cooling Towers, Co. In the Matter of: 09-BIS-006, Aqua-Loop Cooling Towers, Co., P.O. Box 966, Folsom...Order Relating to Aqua-Loop Cooling Towers, Co. The Bureau of...

2010-04-02

214

A numerical simulation of heat transfer in evaporative cooling towers  

Science.gov (United States)

A phenomenological analysis was developed for the processes which occur within an evaporative cooling tower. The analysis includes the basic principles of mass, momentum, and energy conservation and empirical elationships for component characteristics such as transfer and pressure drop coefficients. A computer model which simulates the processes occurring in evaporative cooling towers was developed. The results of this computer model are compared to field data to verify the analysis and the computer modeling. The computer model may be used to analyze the performance of existing towers or to predict the performance of alternative tower designs.

Benton, D. J.

1983-09-01

215

Thermal performance upgrade of the Arkansas Nuclear One cooling tower: A ''root cause'' analysis approach  

International Nuclear Information System (INIS)

The thermal performance efficiency of the natural draft cooling tower at Entergy Operations' 858 MWe Arkansas Nuclear One, Unit 2 was successfully upgraded to 101% of design performance capability in April 1994 as the end result of a unique root-cause analysis of the cooling tower's long-standing performance deficiencies. Through application of state-of-the-art diagnostic testing methods and computer modeling techniques, Entergy was able to identify and correct air/water maldistribution problems in the 447 foot tall counterflow cooling tower at minimal cost. Entergy estimates that the savings realized, as a result of the 1.2 F reduction in cooling tower outlet water temperature, will pay for the thermal upgrade project in approximately 14 months

216

Discrete model-based operation of cooling tower based on statistical analysis  

International Nuclear Information System (INIS)

Highlights: • We introduce an index to describe the cooling capability of a cooling tower. • The effect of ambient air on cooling capability is studied by statistics analysis. • Physical-meaningful and precise-enough model is built by actual operation data. • The application to a real cooling tower is promising for energy conservation. - Abstract: This study is aimed to utilize the operation data to build a physical-meaningful and precise-enough model to assist the operation of a cooling tower. To do so, this work introduces a dimensionless index, which can describe the cooling capability of a cooling tower in terms of effective power utilization. In the first phase of this study, principal component analysis, one of factor analysis methods, is used to investigate effects of ambient air temperature and relative humidity on the cooling capability of a cooling tower. Based on the proposed cooling capability index, the operation data are partitioned into different groups by the fuzzy c-mean clustering algorithm. The resulted groups are distinctly categorized by the conditions of ambient air temperature and relative humidity. In the second phase of the study, data within the same mode of a set of fans are partitioned by the fuzzy c-mean clustering algorithm. The resulted groups of data are then modeled by linear regression. The acquired multiple models are highly accurate in predicting the output temperature of cooling water from the cooling tower. The acquired models assist the operator to accurately select the proper fan mode when process conditions, e.g., cooling loading, or environment conditions, e.g., ambient air temperature, change. It results in electricity saving. This study is concluded by the presentation of a discrete model-based approach to determine the fan mode. The application to a real cooling tower in an iron and steel plant is promising in saving electricity consumed by the fan set

217

Strategy for the Operation of Cooling Towers with variable Speed Fans  

CERN Document Server

Within the SPS Cooling Water Project at CERN aimed at the reduction of water consumption, this primary open cooling loop will be closed and all the primary cooling circuit components will be upgraded to the new required duty and brought to the necessary safety and operability standards. In particular the tower fans will be fitted with variable frequency drives to replace the existing two speed motors. This paper presents a study to optimize the operation of SPS cooling towers taking into account outdoor conditions (wet and dry bulb temperatures) and the entirety of the primary circuit in which they will operate.

Iñigo-Golfín, J

2001-01-01

218

Drift measurements at ENEL ISTRIA pilot cooling tower  

International Nuclear Information System (INIS)

The present paper shows the experimental results of drift measurements obtained in the ISTRIA pilot cooling tower that ENEL has built in Livorno. The determination of drift has been performed by measuring the content of silica in the water released by a sample of fluid mixture collected just above the drop separators. The obtained results seem to indicate the influence of the drop separators geometry on the drift, showing that the most complex geometry gives the corresponding lowest values of drift and vice versa. Such low values of drift are nevertheless payed with an increase in the pressure drop in the drop separation zone

219

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health reasons. A numerical model to study the influence of sychrometric ambient conditions on cooling tower drift deposition was developed. The mathematical model presented, consisting of two coupled sets of conservation equations for the continuous and discrete phases, was incorporated in the general purpose CFD code Fluent. Both experimental plume performance and drift deposition were employed...

Lucas Marti?nez, Manuel; Ruiz Rami?rez, Javier; Sa?nchez Kaiser, Antonio; Viedma, A.; Marti?nez Beltra?n, Pedro Juan

2010-01-01

220

Fire behaviour of cooling tower packing; Brandverhalten von Kuehlturmeinbauten  

Energy Technology Data Exchange (ETDEWEB)

The rapid burning down of the cooling tower of the shutdown power plant in Schwandorf revealed the potential of a total loss of a cooling tower in case of fire. VGB ordered a research project in order to obtain more knowledge about the fire risk of cooling tower packing currently applied. Depending on kind and age of the plastics used, the results of these tests manifest a big variation of the fire behaviour. For the applications of plastics, it is essential to determine and to adhere to organisational fire protection measures. (orig.)

Mattausch, Tim [DMT GmbH und Co. KG, Dortmund (Germany). Fachstelle fuer Brandschutz

2013-10-01

 
 
 
 
221

Experimental investigation of the hydraulic characteristics of a counter flow wet cooling tower  

International Nuclear Information System (INIS)

Thermal and nuclear electric power plants as well as several industrial processes invariably discharge considerable energy to their surrounding by heat transfer. Although water drawn from a nearby river or lake can be employed to carry away this energy, cooling towers offer an excellent alternative particularly in locations where sufficient cooling water cannot be easily obtained from natural sources or where concern for the environment imposes some limits on the temperature at which cooling water can be returned to the surrounding. This paper concerns an experimental investigation of the hydraulic characteristics of a counter flow wet cooling tower. The tower contains a 'VGA.' (Vertical Grid Apparatus) type packing which is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross sectional test area of 0.15 m x 0.148 m. The present investigation is focused mainly on the effect of the air and water flow rates on the hydraulic characteristics of the cooling tower, for different inlet water temperatures. The two hydrodynamic operating regimes which were observed during the air/water contact operation within the tower, namely the Pellicular Regime (PR) and the Bubble and Dispersion Regime (BDR) have enabled to distinguish two different states of pressure drop characteristics. The first regime is characterized by low pressure drop values, while in the second regime, the pressure drop values are relatively much higher than those observed in the first one. The dependence between the pressure drop characteristics and the combined heat and mass transport (air-water) through the packing inside the cooling tower is also highlighted. The obtained results indicate that this type of tower possesses relatively good hydraulic characteristics. This leads to the saving of energy. -- Highlights: ? Cooling towers are widely used to reject waste heat from thermal and nuclear electric power plants to the atmosphere. ? The hydraulic characteristics of a counter flow wet cooling tower have been studied experimentally. ? The effect of the air and water flow rates on the hydraulic characteristics of tower was investigated. ? Different inlet water temperatures: 35 oC, 43 oC and 50 oC, respectivelly, were used in the investigation. ? The results indicate that this type of tower possesses relatively good hydraulic characteristics.

222

Performance prediction of a multi-stage wind tower for indoor cooling  

Science.gov (United States)

A theoretical model is developed to establish an in-depth understanding of the performance of a three-stage wind tower with a bypass system for indoor cooling in rural dry and hot climates. Model simulations are presented for a wide range of ambient conditions that include inlet wind speed, inlet temperature and relative humidity. Simulation results provide an insight into the desirable water flow rates and air-to-water loadings for comfort zone temperatures and relative humidity levels at the exit of the wind tower. Simulations show wind towers with variable cross-sections provide an increase in the cooling power for the same inlet wind speed, inlet air temperature and relative humidity when compared to wind towers with a constant cross-section. The study shall lead to a better understanding to designing wind towers that are both environmentally friendly and energy efficient.

Issa, Roy J.; Chang, Byungik

2012-08-01

223

Safety analysis for K reactor and impact of cooling tower installation  

International Nuclear Information System (INIS)

This paper describes the safety analysis of the Savannah River site K-reactor loss-of-cooling-water-supply (LOCWS) event and the impact on the analysis of a natural-draft cooling tower, which was installed in 1992. Historically (1954 to 1992), the K-reactor secondary cooling system [called the cooling water system (CWS)] used water from the Savannah River pumped to a 25-million-gal basin adjacent to the reactor. Approximately 170 000 gal/min were pumped from the basin through heat exchangers to remove heat from the primary cooling system. This water then entered a smaller basin, where it flowed over a weir and eventually returned to the Savannah River. The 25-million-gal basin is at a higher elevation than the heat exchangers and the smaller basin to supply cooling by gravity flow (which is sufficient to remove decay heat) if power to the CWS pumps is interrupted. Small amounts of cooling water are also used for other essential equipment such as diesels, motors, and oil coolers. With the cooling tower installed, ?85% of the cooling water flows from the small basin by gravity to the cooling tower instead of returning to the Savannah River. After being cooled, it is pumped back to the 25-million-gal basin. River water is supplied only to make up for evaporation and the blowdown stream

224

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers  

International Nuclear Information System (INIS)

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative 'dry' cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influencedal in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered

225

Numerical simulation of a cooling tower coupled with heat pump system associated with single house using TRNSYS  

International Nuclear Information System (INIS)

Highlights: • We simulate a cooling tower coupled with heat pump system and a single zone using TRNSYS. • We examine the temperature of water inside the cooling tower and inside the single zone. • We study the temporal evolution of the all parameters for 4500 h operation in winter in Tunisia. - Abstract: The industrial cooling towers in Tunisia meet difficulties due to the poor coordination between the utility and process sectors. In this study, we will consider especially the vapor recovery of the wastewater from the industrial activity in south Tunisia. By using the heat pump for high capacity, the problem for vapor from wastewater may be resolved. The coupling for the cooling tower and the heat pump system is investigated by TRNSYS software. The system of cooling tower is also associated with a single zone which is related to heat exchangers. An optimization model for the operation of a cooling water system was developed that accounts for a cooling tower, and a network of pipelines and heat exchangers for heating a single house. This work is based on numerical studies; the cooling tower performance, the single house, the heat pump and the heat exchanger that are simulated using TRNSYS model. The circulation of cooling water system is assured by a counter flow. The evaluations of the cooling tower geometry and performances are based on an adaptive version of Merkel’s method witch integrated in TRNSYS. The results of optimization using TRNSYS are validated by several theoretical and experimental studies

226

Dry cooling towers, a comparative analysis and possibilities for their implementation in Macedonia  

International Nuclear Information System (INIS)

The need for supplying the great quantities of additional water for compensation of water looses in circulating cooling systems in thermal power units represent a distinct problem. In cases when this problem result in limitation of power energy production, the solution of this problem can be obtained using new technological solutions for cooling using dry cooling towers, system HELLER, which have no need for additional water for compensation of evaporating looses. (Authors)

227

Natural-draught cooling towers made of reinforced concrete  

International Nuclear Information System (INIS)

Large power plant units and dry cooling tower technology require larger dimensions for natural-draught cooling towers. The main curvation radii in latitudinal and meridian direction are thus increased, which results in a lower three-dimensional support strength. This development is an incentive for constant re-consideration of calculation methods, safety philosophy, and dimensioning criteria. In this context, wind effects have been re-formulated and given a scientific foundation. Constructional measures to improve the static and dynamic behaviour of the structure have been presented and critically assessed. A cost analysis, finally, gave the most rational applications of the new shell construction with reinforcing elements. A cooling tower now under construction gave a realistic example. Fundamental aspects concerning the foundations of cooling tower shells and two special types of foundation are further points to clarify the subject. (orig./HP)

228

EXPERIMENTAL SIMULATION OF SINGLE AND MULTIPLE CELL COOLING TOWER PLUMES  

Science.gov (United States)

An experimental investigation was conducted to determine the dilution characteristics of single and multiple port buoyant discharges typical of modern natural and mechanical draft cooling towers. Simultaneous measurements of velocity and tracer concentration profiles were taken a...

229

Lower parts of Temelin nuclear power plant cooling towers  

International Nuclear Information System (INIS)

The progress of work is described in detail on the foundations and lower parts of the cooling towers of the Temelin nuclear power plant. The cooling tower is placed on a reinforced concrete footing of a circular layout. Support pillars are erected on the reinforced concrete continuous footing. They consists of oblique shell stanchions. Inside, the footing joins up to monolithic wall and slab structures of the cooling tower tub. The tub bottom forms a foundation plate supporting prefab structures of the cooling tower inner structural systems. The framed support of the chimney shell consists of 56 pairs of prefabricated oblique stanchions. Following their erection into the final position and anchoring in the continuous footing, the concreting of the casing can start of the reinforced conrete chimney. (Z.M.). 3 figs

230

Work of the condensation unit of NPP with evaporative cooling tower  

International Nuclear Information System (INIS)

The analysis of cooling system work of power unit of NPP consisting from a condenser of turbine and with the area of an irrigation 10 000 m2 is presented. Productivity of the evaporative cooling tower and the overall efficiency of condenser, effecting on power characteristics of NPP are defined. Influence of external conditions during a year cycle on parameters of the power unit of NPP is considered. Tabular and graphic dependences of cooling water temperature changes in cooling tower, temperatures and pressure of the condensation are received. (authors).

231

Evaluation of IR technology applied to cooling tower performance  

Science.gov (United States)

Infrared thermography (IR) is widely used by electric utilities as an integral part of their predictive maintenance program. IR is utilized for inspection of a variety of plant mechanical and electrical components. Additionally, IR can be used to provide thermal performance information for other key plant systems, including assessment of cooling towers. Cooling tower performance directly affects availability and heat rate in fossil and nuclear power plants. Optimal tower performance contributes to efficient turbine operation and maximum power output. It is estimated that up to half of the cooling towers installed have failed to meet their design performance specifications. As a result, any additional degradation of tower performance resulting from fouling, valve degradation, unbalanced flow, or a poor maintenance practice has a direct effect on generation output. We have collected infrared thermography images of mechanical draft cooling towers, as part of Evaluation of IR Technology Applied to Cooling Tower Performance. IR images have been analyzed to provide information regarding general performance conditions and identification of operational deficiencies related to thermal performance. Similarly, IR can be implemented for monitoring of tower flow balance activities and for post-maintenance surveillance. To date, IR images have been used to identify areas of general flow imbalance, flooding or limited flow in individual cells, missing or broken tower fill material, fan performance and other problems related to maintenance or operational issues. Additionally, an attempt is being made to use quantitative thermal data, provided by the IR image analysis software, in conjunction with condenser input/output site ambient information, to evaluate and compare individual tower cell performance.

MacNamara, Neal A.; Zayicek, Paul A.

1999-03-01

232

Experimental investigation of the performance characteristics of a counterflow wet cooling tower  

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation of the performance characteristics of a counter flow wet cooling tower represented by the heat rejected by the tower and its thermal effectiveness is presented in this paper. The tower is filled with a 'VGA.' (Vertical Grid Apparatus) type packing which is 0.42 m high and contains four (04) galvanized sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross-sectional test area of 0.15 m - 0.148 m. The investigation is concerned mainly on the effect of the air, water flow rates and the inlet water temperatures on the thermal effectiveness of the cooling tower as well as the heat rejected by this tower from water to be cooled to the air stream discharged into the atmosphere. The two operating regimes which were observed during the air/water contact inside the tower, a Pellicular Regime (PR) and a Bubble and Dispersion Regime (BDR) appear to be important, as The BDR regime enables to cool larger amount of water flow rates, while the Pellicular regime results with higher thermal effectiveness. (authors)

Lemouari, M. [Department of Process Engineering, Faculty of Technology, University of Bejaia (Algeria); Boumaza, M. [Department of Chemical Engineering, College of Engineering, King Saud University(Saudi Arabia)

2010-10-15

233

Experimental investigation of the performance characteristics of a counterflow wet cooling tower  

International Nuclear Information System (INIS)

An experimental investigation of the performance characteristics of a counter flow wet cooling tower represented by the heat rejected by the tower and its thermal effectiveness is presented in this paper. The tower is filled with a 'VGA.' (Vertical Grid Apparatus) type packing which is 0.42 m high and contains four (04) galvanized sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross-sectional test area of 0.15 m - 0.148 m. The investigation is concerned mainly on the effect of the air, water flow rates and the inlet water temperatures on the thermal effectiveness of the cooling tower as well as the heat rejected by this tower from water to be cooled to the air stream discharged into the atmosphere. The two operating regimes which were observed during the air/water contact inside the tower, a Pellicular Regime (PR) and a Bubble and Dispersion Regime (BDR) appear to be important, as The BDR regime enables to cool larger amount of water flow rates, while the Pellicular regime results with higher thermal effectiveness. (authors)

234

Closed-type cooling system with cooling towers for modern NNPs  

International Nuclear Information System (INIS)

Arrangement decisions and prospects of the development of closed-type cooling systems with cooling towers for modern NPPs are considered. Design solutions, process parameters, technical and economical properties of large cooling towers for 100x103 and 180x103 m3/h NPP and heat-and-power nuclear plants are presented

235

Performance evaluations of steam power plants with dry cooling towers  

International Nuclear Information System (INIS)

A theoretical model is presented to design dry cooling tower systems and to evaluate their off-design performances. The influence of the more important design parameters on the tower dimensions is shown. A preliminary ''optimum'' size is predicted by means of a computer code using a simplified cost model. Moreover the influence of the designed cooling system on the performance of thermoelectric and/or nuclear power plants is analysed

236

Environmental Impacts from the Operation of Cooling Towers at SRP  

International Nuclear Information System (INIS)

An assessment has been made of the environmental effects that would occur from the operation of cooling towers at the SRP reactors. A more realistic numerical model of the cooling tower plume has been used to reassess the environmental impacts. The following effects were considered: (1) the occurrence of fog and ice and their impact on nearby structures, (2) drift and salt deposition from the plume, (3) the length and height of the visible plume, and (4) the possible dose from tritium

237

Rainfall enhancement due to washout of cooling tower condensate  

International Nuclear Information System (INIS)

Theoretical calculations of the washout of cooling tower condensate droplets by frontal raindrops show that rainfall enhancement can be significant and is measurable under typical meteorological and cooling tower effluent source conditions. For the case of moderate rainfall rates and a wind speed of 5 m/sec, centerline rainfall enhancement was as much as 46%, cross-plume average enhancement as much as 7%, and distance to one-half depletion of the source 1 to 10 km

238

Stimulatory effect of cooling tower biocides on amoebae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two species of amoebae were isolated from the cooling tower of an air-conditioning system and examined for effects of exposure to four cooling tower biocides, a thiocarbamate compound, tributyltin neodecanoate mixed with quaternary ammonium compounds, another quaternary ammonium compound alone, and an isothiazolin derivative. The amoebae isolated were Acanthamoeba hatchetti and a Cochliopodium species. Two other amoeba cultures, an A. hatchetti culture and Cochliopodium bilimbosum, were obtai...

Srikanth, S.; Berk, S. G.

1993-01-01

239

Distribution of monoclonal antibody subgroups and sequence-based types among Legionella pneumophila serogroup 1 isolates derived from cooling tower water, bathwater, and soil in Japan.  

Science.gov (United States)

Legionella pneumophila serogroup (SG) 1 is the most frequent cause of legionellosis. This study analyzed environmental isolates of L. pneumophila SG 1 in Japan using monoclonal antibody (MAb) typing and sequence-based typing (SBT). Samples were analyzed from bathwater (BW; n = 50), cooling tower water (CT; n = 50), and soil (SO; n = 35). The distribution of MAb types varied by source, with the most prevalent types being Bellingham (42%), Oxford (72%), and OLDA (51%) in BW, CT, and SO, respectively. The ratios of MAb 3/1 positive isolates were 26, 2, and 14% from BW, CT, and SO, respectively. The environmental isolates from BW, CT, and SO were divided into 34 sequence types (STs; index of discrimination [IOD] = 0.973), 8 STs (IOD = 0.448), and 11 STs (IOD = 0.879), respectively. Genetic variation among CT isolates was smaller than seen in BW and SO. ST1 accounted for 74% of the CT isolates. The only common STs between (i) BW and CT, (ii) BW and SO, and (iii) CT and SO were ST1, ST129, and ST48, respectively, suggesting that each environment constitutes an independent habitat. PMID:22492442

Amemura-Maekawa, Junko; Kikukawa, Kiyomi; Helbig, Jürgen H; Kaneko, Satoko; Suzuki-Hashimoto, Atsuko; Furuhata, Katsunori; Chang, Bin; Murai, Miyo; Ichinose, Masayuki; Ohnishi, Makoto; Kura, Fumiaki

2012-06-01

240

Simultaneous detection of Legionella species and Legionella pneumophila by duplex PCR (dPCR assay in cooling tower water samples from Jakarta, Indonesia  

Directory of Open Access Journals (Sweden)

Full Text Available Aim: Since culture method is time-consuming and has low  sensitivity, we developed a duplex PCR (dPCR assay for the detection of Legionella sp. and L. pneumophila in cooling tower samples. We used culture method as a gold standard.Methods: Optimization of dPCR method was performed to obtain an assay with high sensitivity and specifi city. The optimized method was used to detect Legionella sp. dan L. pneumophila in 9 samples obtained from 9 buildings in Jakarta. For culture method, the bacteria were grown or isolated on selective growth factor supplemented-buffered charcoal yeast extract (BCYE media.Results: Of 9 samples tested by dPCR assay, 6 were positive for Legionella species,1 was positive for L. pneumophila, and 2 showed negative results. For the same samples, no Legionella sp. was detected by the culture method.Conclusion: dPCR assay was much more sensitive than the culture method and was potentially used as a rapid, specifi c and sensitive test for routine detection of Legionella sp. dan for L. pneumophila in water samples. (Med J Indones 2010; 19:223-7Keywords: BCYE media, mip gene, 16S-rRNA gene

Andi Yasmon

2010-11-01

 
 
 
 
241

Simultaneous detection of Legionella species and Legionella pneumophila by duplex PCR (dPCR) assay in cooling tower water samples from Jakarta, Indonesia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aim: Since culture method is time-consuming and has low  sensitivity, we developed a duplex PCR (dPCR) assay for the detection of Legionella sp. and L. pneumophila in cooling tower samples. We used culture method as a gold standard.Methods: Optimization of dPCR method was performed to obtain an assay with high sensitivity and specifi city. The optimized method was used to detect Legionella sp. dan L. pneumophila in 9 samples obtained from 9 buildin...

Andi Yasmon; Yusmaniar Yusmaniar; Anis Anis; Budiman Bela

2010-01-01

242

Experimental study on the performance of mechanical cooling tower with two types of film packing  

Energy Technology Data Exchange (ETDEWEB)

In this work, an experimental and a comparative study on terms of tower characteristics (KaV/L), water to air flow ratio (L/G) and efficiency for two film type packings are presented for a wide range of (L/G) ratio from 0.2 to 4. The packings used in this work are vertical corrugated packing (VCP) and horizontal corrugated packing (HCP). The obtained results showed that the performance of the cooling tower is affected by the type and arrangement of the packings. Also, the tower performance showed a decrease with an increase in the (L/G) ratio as is also observed in other types of cooling towers. The results showed the tower with vertical corrugated packing (VCP) has higher efficiency than the one with horizontal corrugated packing (HCP)

Gharagheizi, Farhad [Department of Chemical Engineering, Faculty of Engineering, University of Tehran, PO Box 11365-4563, Tehran (Iran, Islamic Republic of)]. E-mail: fghara@engmail.ut.ac.ir; Hayati, Reza [Department of Chemical Engineering, Faculty of Engineering, University of Tehran, PO Box 11365-4563, Tehran (Iran, Islamic Republic of); Fatemi, Shohreh [Department of Chemical Engineering, Faculty of Engineering, University of Tehran, PO Box 11365-4563, Tehran (Iran, Islamic Republic of)

2007-01-15

243

Experimental study on the performance of mechanical cooling tower with two types of film packing  

International Nuclear Information System (INIS)

In this work, an experimental and a comparative study on terms of tower characteristics (KaV/L), water to air flow ratio (L/G) and efficiency for two film type packings are presented for a wide range of (L/G) ratio from 0.2 to 4. The packings used in this work are vertical corrugated packing (VCP) and horizontal corrugated packing (HCP). The obtained results showed that the performance of the cooling tower is affected by the type and arrangement of the packings. Also, the tower performance showed a decrease with an increase in the (L/G) ratio as is also observed in other types of cooling towers. The results showed the tower with vertical corrugated packing (VCP) has higher efficiency than the one with horizontal corrugated packing (HCP)

244

Potentially pathogenic amoeba-associated microorganisms in cooling towers and their control.  

Science.gov (United States)

Cooling towers provide a favorable environment for the proliferation of microorganisms. Cooling towers generate a biofilm and often aerosolize contaminated water, thereby increasing the risk of microorganism dissemination by human inhalation. This pathogen dissemination was first revealed by the epidemics of Legionnaires' disease that were directly related to the presence of cooling towers, and since then, the ecology of Legionella pneumophila has been well studied. Each country has specific standards regarding the acceptable amount of microorganisms in cooling tower systems. However, those standards typically only concern L. pneumophila, even though many other microorganisms can also be isolated from cooling towers, including protozoa, bacteria and viruses. Microbiological control of the cooling tower system can be principally achieved by chemical treatments and also by improving the system's construction. Several new treatments are being studied to improve the efficiency of disinfection. However, as most of these treatments continue to focus solely on L. pneumophila, reports of other types of pathogens continue to increase. Therefore, how their dissemination affects the human populous health should be addressed now. PMID:19492970

Pagnier, Isabelle; Merchat, Michèle; La Scola, Bernard

2009-06-01

245

High Flux Isotopes Reactor (HFIR) Cooling Towers Demolition Waste Management  

International Nuclear Information System (INIS)

This paper describes the results of a joint initiative between Oak Ridge National Laboratory, operated by UT-Battelle, and Bechtel Jacobs Company, LLC (BJC) to characterize, package, transport, treat, and dispose of demolition waste from the High Flux Isotope Reactor (HFIR), Cooling Tower. The demolition and removal of waste from the site was the first critical step in the planned HFIR beryllium reflector replacement outage scheduled. The outage was scheduled to last a maximum of six months. Demolition and removal of the waste was critical because a new tower was to be constructed over the old concrete water basin. A detailed sampling and analysis plan was developed to characterize the hazardous and radiological constituents of the components of the Cooling Tower. Analyses were performed for Resource Conservation and Recovery Act (RCRA) heavy metals and semi-volatile constituents as defined by 40 CFR 261 and radiological parameters including gross alpha, gross beta, gross gamma, alpha-emitting isotopes and beta-emitting isotopes. Analysis of metals and semi-volatile constituents indicated no exceedances of regulatory limits. Analysis of radionuclides identified uranium and thorium and associated daughters. In addition 60Co, 99Tc, 226Rm, and 228Rm were identified. Most of the tower materials were determined to be low level radioactive waste. A small quantity was determined not to be radioactive, or could be decontaminated. The tower was dismantled October 2000 to Januatower was dismantled October 2000 to January 2001 using a detailed step-by-step process to aid waste segregation and container loading. The volume of waste as packaged for treatment was approximately 1982 cubic meters (70,000 cubic feet). This volume was comprised of plastic (?47%), wood (?38%) and asbestos transite (?14%). The remaining ?1% consisted of the fire protection piping (contaminated with lead-based paint) and incidental metal from conduit, nails and braces/supports, and sludge from the basin. The waste, except for the asbestos, was volume reduced via a private contract mechanism established by BJC. After volume reduction, the waste was packaged for rail shipment. This large waste management project successfully met cost and schedule goals

246

Evaluation of the RSG-GAS cooling tower performance  

International Nuclear Information System (INIS)

Utilization of RSG-GAS reactor should be operated as efficiently as possible, so that reactor operation planning using one line primary coolant can be anticipated. To analyze the performance of the RSG-GAS cooling tower with one line primary coolant doing by using same data from 10 MW thermal reactor operation. The result were then compare to those achieved using CATHENA code. The results indicated that, for design condition the ratio of water flowrate to air is (L/G) 1.52 and number transfer unit (NTU) is 0.348. For operation condition, the average of L/G and NTU are respectively 1.37 and 0,348. Moreover the results achieved by the code showed that L/G and NTU are respectively 1.35 and 0,302. The performance of cooling tower achieved operation condition and the code results are respectively 91% and 72%. This means that the calculated results are lower than measurement results

247

Experimental study and predictions of an induced draft ceramic tile packing cooling tower  

International Nuclear Information System (INIS)

Deterioration of the filling material in traditional cooling towers is of serious concern. In this study, long life burned clay is used as the filling material. It guards against common cooling tower problems resulting from chemical water treatment and deterioration. The size of the ceramic packing material and outlet conditions predictions by theoretical modeling require heat and mass transfer correlations. An experimental study to evaluate the heat and mass transfer coefficients is conducted. The previous correlations found in the literature could not predict the mass transfer coefficient for the tested tower. A mass transfer coefficient correlation is developed, and new variables are defined. This correlation can predict the mass transfer coefficient within an error of ±10%. The developed correlation is used along with theoretical modeling to predict the cooling tower outlet conditions within an error of ±5%

248

Flue gas injection control of silica in cooling towers.  

Energy Technology Data Exchange (ETDEWEB)

Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.

Brady, Patrick Vane; Anderson, Howard L., Jr.; Altman, Susan Jeanne

2011-06-01

249

Alternative geometry for cylindrical natural draft cooling tower with higher cooling efficiency under crosswind condition  

International Nuclear Information System (INIS)

Highlights: • Alternative cross sections for natural draft cooling tower were proposed. • Numerical solution was applied to study thermal and hydraulic performances. • Thermal and hydraulic performances were assessed by comparative parameters. • Cooling tower with elliptical cross section had better thermal performance under crosswind. • It could successfully used at the regions with invariant wind direction. - Abstract: Cooling efficiency of a natural draft dry cooling tower may significantly decrease under crosswind condition. Therefore, many researchers attempted to improve the cooling efficiency under this condition by using structural or mechanical facilities. In this article, alternative shell geometry with elliptical cross section is proposed for this type of cooling tower instead of usual shell geometry with circular cross section. Thermal performance and cooling efficiency of the two types of cooling towers are numerically investigated. Numerical simulations show that cooling tower with elliptical cross section improves the cooling efficiency compared to the usual type with circular cross section under high-speed wind moving normal to the longitudinal diameter of the elliptical cooling tower

250

Atmospheric wet-type cooling tower with antifreeze system  

International Nuclear Information System (INIS)

The cooling tower has air inlets at its base, a network of pipes which distributes the air to be cooled above the packing, and valves to isolate a part of the network. It includes also a bypass circuit, provided with means to control the flow rate fraction which is by-passed

251

Statistical multi-model approach for performance assessment of cooling tower  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a data-driven model-based assessment strategy to investigate the performance of a cooling tower. In order to achieve this objective, the operations of a cooling tower are first characterized using a data-driven method, multiple models, which presents a set of local models in the format of linear equations. Satisfactory fuzzy c-mean clustering algorithm is used to classify operating data into several groups to build local models. The developed models are then applied to predict the performance of the system based on design input parameters provided by the manufacturer. The tower characteristics are also investigated using the proposed models via the effects of the water/air flow ratio. The predicted results tend to agree well with the calculated tower characteristics using actual measured operating data from an industrial plant. By comparison with the design characteristic curve provided by the manufacturer, the effectiveness of cooling tower can be obtained in the end. A case study conducted in a commercial plant demonstrates the validity of proposed approach. It should be noted that this is the first attempt to assess the cooling efficiency which is deviated from the original design value using operating data for an industrial scale process. Moreover, the evaluated process need not interrupt the normal operation of the cooling tower. This should be of particular interest in industrial applications. (author)

Pan, Tian-Hong [School of Electrical and Information Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Shieh, Shyan-Shu [Department of Occupational Safety and Health, Chang Jung Christian University, 71101 (China); Jang, Shi-Shang; Tseng, Wen-Hung [Chemical Engineering Department, National Tsing-Hua University, Hsin-Chu 30047 (China); Wu, Chan-Wei; Ou, Jenq-Jang [Energy and Air Pollution Control Section, New Materials Research and Development Dept., China Steel Corporation, Kaohsiung 80012 (China)

2011-02-15

252

Statistical multi-model approach for performance assessment of cooling tower  

International Nuclear Information System (INIS)

This paper presents a data-driven model-based assessment strategy to investigate the performance of a cooling tower. In order to achieve this objective, the operations of a cooling tower are first characterized using a data-driven method, multiple models, which presents a set of local models in the format of linear equations. Satisfactory fuzzy c-mean clustering algorithm is used to classify operating data into several groups to build local models. The developed models are then applied to predict the performance of the system based on design input parameters provided by the manufacturer. The tower characteristics are also investigated using the proposed models via the effects of the water/air flow ratio. The predicted results tend to agree well with the calculated tower characteristics using actual measured operating data from an industrial plant. By comparison with the design characteristic curve provided by the manufacturer, the effectiveness of cooling tower can be obtained in the end. A case study conducted in a commercial plant demonstrates the validity of proposed approach. It should be noted that this is the first attempt to assess the cooling efficiency which is deviated from the original design value using operating data for an industrial scale process. Moreover, the evaluated process need not interrupt the normal operation of the cooling tower. This should be of particular interest in industrial applications.

253

Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant  

Energy Technology Data Exchange (ETDEWEB)

The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified with concentrations in plant materials (fescue grass) decreasing with increasing distance from the cooling tower. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. Results suggest that differences in retention in litter and foliage are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil-water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Preliminary model estimates of drift deposition are compared to deposition measurements.

Taylor, F. G.; Hanna, S. R.; Parr, P. D.

1978-12-01

254

Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant  

International Nuclear Information System (INIS)

The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified with concentrations in plant materials (fescue grass) decreasing with increasing distance from the cooling tower. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. Results suggest that differences in retention in litter and foliage are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil-water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Preliminary model estimates of drift deposition are compared to deposition measurements

255

Microphysical and optical features of polluted cooling tower clouds  

Science.gov (United States)

In November 1993 an airborne field study was performed in order to investigate the microphysical and radiative properties of cooling tower water clouds initiated by water vapour emissions and polluted by the exhaust from coal-fired power plants. The number-median diameter of the droplet size distributions of these artificial clouds was in the range of 13 ?m. The concentration of smaller droplets (diameters dD bimodal spectra were found with a second mode at 19 ?m. The liquid water content (LWC) ranged between 2 and 5 g/m 3 and effective droplet radii ( Re) between 6 and 9 ?m were measured. LWC and Re decreased with altitude, whereas the droplet concentration ( ND) remained approximately constant (about 2000 cm -3 ). An enrichment of interstitial aerosol particles with particle diameters ( dp) smaller 0.2 ?m compared to the power plant plume in the vicinity of the clouds was observed. Particle activation for dm > 0.3 ?m. was evident, especially in cooling tower clouds further apart and separated from their sources. Furthermore, radiation measurements were performed, which revealed differences in the vertical profiles of downwelling solar and UV radiation flux densities inside the clouds. The effective droplet radius Re was parameterized in terms of LWC and ND using equations known from literature. The close agreement between measured and parameterized Re indicates a similar coupling of Re, LWC and ND as in natural clouds. By means of Mie calculations, volume scattering coefficients and asymmetry factors are derived for both the cloud droplets and the aerosol particles. For the cloud droplets, the optical parameters were described by parameterizations from the literature. The results show, that the link between radiative and microphysical properties of natural clouds is not changed by the extreme pollution of the artificial clouds.

Mertes, S.; Wendisch, M.

256

Cooling towers--a potential environmental source of slow-growing mycobacterial species.  

Science.gov (United States)

Over the last decade a rise in the frequency of disease caused by nontuberculous mycobacteria (NTM) has occurred, especially among AIDS patients. The lack of evidence for person-to-person transmission indicates the environment is a source of infection. The ecology and environmental sources of NTMs are poorly understood, and many pathogenic strains have not been observed outside of clinical cases. Several species of NTMs have been reported from treated water distribution systems; however, one type of manmade environment that has not been examined for mycobacteria is that of cooling towers of air-conditioning systems. Such environments not only harbor a variety of microbial species, they also disseminate them in aerosols. The present investigation examined nine cooling towers from various locations in the United States. Cooling tower water was concentrated, treated with cetylpyridinium chloride, and plated onto Middlebrook 7H10 agar supplemented with OADC and cycloheximide. Colonies presumed to be mycobacterial species were isolated and acid-fast stained. Identification was made by amplifying and sequencing 1450 bp fragments of the 16S rRNA gene in both directions, and comparing resulting sequences with those in GenBank. Results showed that at least 75% of tower samples contained NTMs, and most of the isolates closely matched known mycobacterial pathogens. Isolates most closely matched the following GenBank sequences: Mycobacterium intracellulare, M. szulgai, M. bohemicum, M. gordonae, M. nonchromogenicum, and M. n. sp. "Fuerth 1999." This is the first report of specific NTMs in cooling tower water, and the first report of M. n. sp. "Fuerth 1999" from any environmental sample. Although cooling towers have a relatively high pH, they may favor the growth and dissemination of such potential pathogens, and future epidemiologic investigations should consider cooling towers as possible environmental sources of mycobacteria. PMID:12688848

Black, Walter C; Berk, Sharon G

2003-01-01

257

Computer optimization of dry and wet/dry cooling tower systems for large fossil and nuclear power plants  

International Nuclear Information System (INIS)

This study determined the cost of dry cooling compared to the conventional cooling methods. Also, the savings by using wet/dry instead of all-dry cooling were determined. A total optimization was performed for power plants with dry cooling tower systems using metal-finned-tube heat exchangers and surface condensers. The optimization minimizes the power production cost. The program optimizes the design of the heat exchanger and its air and water flow rates. In the base case study, the method of replacing lost capacity assumes the use of gas turbines. As a result of using dry cooling towers in an 800 MWe fossil plant, the incremental costs with the use of high back pressure turbine and conventional turbine over all-wet cooling are 11 and 15%, respectively. For a 1200 MWe nuclear plant, these are 22 and 25%, respectively. Since the method of making up lost capacity depends on the situation of a utility, considerable effort has been placed on testing the effects of using different methods of replacing lost capacity at high ambient temperatures by purchased energy. The results indicate that the optimization is very sensitive to the method of making up lost capacity. It is, therefore, important to do an accurate representation of all possible methods of making up capacity loss when optimizating power plants with dry cooling towers. A solution for the problem of losing generation capability by a power plant due to the use of a dry cooling tower is to supplement the dry toweroling tower is to supplement the dry tower during the hours of peak ambient temperatures by a wet tower. A separate wet/dry cooling tower system with series tower arrangement was considered in this study, and proved to be an economic choice over all-dry cooling where some water is available but supplies are insufficient for a totally evaporative cooling tower

258

Analysis of the evaporative towers cooling system of a coal-fired power plant  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents a theoretical analysis of the cooling system of a 110 MW coal-fired power plant located in central Serbia, where eight evaporative towers cool down the plant. An updated research on the evaporative tower cooling system has been carried out to show the theoretical analysis of the tower heat and mass balance, taking into account the sensible and latent heat exchanged during the processes which occur inside these towers. Power plants which are using wet cooling towers fo...

Lakovi? Mirjana S.; Lakovi? Slobodan V.; Banjac Miloš J.

2012-01-01

259

Influence of wind on conditions of plumes at natural draft cooling towers  

International Nuclear Information System (INIS)

It was the objective of this research project, to establish the influence of wind on the emission characteristics, the plume data at the top of cooling towers and on the dispersion of plumes in free atmosphere. Data from field-measurements on a natural draft wet cooling-tower were analyzed systematically, a model for the calculation of the plume characteristics was further developed, and the plume dispersion under different conditions was investigated by a model computation. Plume velocity and cooling air massflow show a minimum at a wind speed around 4 m/s. Their depression in this area of wind speed leads to an increase of the cold water temperature of the cooling tower and hence to a loss of power station efficiency. Temperature and humidity of plume have a maximum value in this area. Halving of wind velocity leads to doubling of the cross section area in the symmetry plane of the plume. (orig./HP)

260

Mistral: New test bench for cooling tower components  

International Nuclear Information System (INIS)

The use of the test bench for cooling tower components of Nantes-Chevire, useful counterflow cross-section: 7m x 7m, has shown the adequacy of this large tool for the study of large equipment and the elimination of the boundary effect (boundary effect coefficient between 1.2 and 1.5). After having decommissioned this bench, Electricite de France built the Mistral bench at the Nuclear Generation Centre of Bugey. It is equipped with two test systems. The cross-section of the counterflow system is 7m x 7m and its useful height, 3.5m. The cross-section of the cross-flow system is 5 x 10m and its depth 10m. Water and air flows can reach respectively 600 1 per sec. and 225m3 per sec. for a maximum thermal capacity of 25 MW

 
 
 
 
261

Successful implementation of ageing management exemplified at the cooling tower of the Emsland nuclear power plant  

International Nuclear Information System (INIS)

The paper describes the successful implementation of the restoration of water distribution channels at the cooling tower of the Emsland nuclear power plant under the aspect of ageing management. The main challenge of ageing management is the determination of potential ageing mechanism and to avoid systematically and effectively their damaging influences. In the course of the annual site inspections, abnormalities at the lower side of the water-distribution channels of the cooling tower were detected, analysed, and repaired. The procedures conserve the load bearing reinforcement only for a certain period. Therefore permanent structural monitoring is needed. (orig.)

262

Monitoring of biofilm-associated Legionella pneumophila on different substrata in model cooling tower system.  

Science.gov (United States)

Cooling towers have the potential to develop infectious concentrations of Legionella pneumophila. Legionella counts increases where biofilm and warm water temperatures are present. In this study, biofilm associated L. pneumophila and heterotrophic bacteria were compared in terms of material dependence. Model cooling tower system was experimentally infected by L. pneumophila standard strain and monthly monitored. Different materials were tested for a period of 180 days. The lowest L. pneumophila and heterotrophic plate counts were measured on plastic polymers, whereas L. pneumophila and heterotrophic bacteria were accumulated rapidly on galvanized steel surfaces. It can be concluded that selection of plastic polymers, as a manufacturing material, are suitable for recirculating water systems. PMID:17219241

Türetgen, Irfan; Cotuk, Aysin

2007-02-01

263

Disinfection of bacterial biofilms in pilot-scale cooling tower systems.  

Science.gov (United States)

The impact of continuous chlorination and periodic glutaraldehyde treatment on planktonic and biofilm microbial communities was evaluated in pilot-scale cooling towers operated continuously for 3 months. The system was operated at a flow rate of 10,080 l day(-1). Experiments were performed with a well-defined microbial consortium containing three heterotrophic bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. The persistence of each species was monitored in the recirculating cooling water loop and in biofilms on steel and PVC coupons in the cooling tower basin. The observed bacterial colonization in cooling towers did not follow trends in growth rates observed under batch conditions and, instead, reflected differences in the ability of each organism to remain attached and form biofilms under the high-through flow conditions in cooling towers. Flavobacterium was the dominant organism in the community, while P. aeruginosa and K. pneumoniae did not attach well to either PVC or steel coupons in cooling towers and were not able to persist in biofilms. As a result, the much greater ability of Flavobacterium to adhere to surfaces protected it from disinfection, whereas P. aeruginosa and K. pneumoniae were subject to rapid disinfection in the planktonic state. PMID:21547755

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron I

2011-04-01

264

A case of nosocomial Legionella pneumonia associated with a contaminated hospital cooling tower.  

Science.gov (United States)

We report the epidemiological investigation of a nosocomial pneumonia case due to Legionella pneumophila linked to a contaminated hospital cooling tower in an immune-compromised patient. A 73-year-old female patient was diagnosed with nosocomial Legionella pneumonia proven by a culture of L. pneumophila serogroup 1 from bronchoalveolar lavage fluid. Two strains isolated from the patient and two strains isolated from two cooling towers were found to be identical using repetitive-sequence-based-PCR with a 95% probability. This Legionella pneumonia case might be caused by aerosol from cooling towers on the roof of the hospital building which was contaminated by L. pneumophila. We increased up the temperature of hot water supply appropriately for prevention of Legionella breeding in an environment of patients' living. On the other hand, as the maintenance of cooling tower, we increased the frequency of Legionella culture tests from twice a year to three times a year. In addition, we introduced an automated disinfectants insertion machine and added one antiseptic reagent (BALSTER ST-40 N, Tohzai Chemical Industry Co., Ltd., Kawasaki, Japan) after this Legionella disease, and thereafter, we have no additional cases of Legionella disease or detection of Legionella spp. from the cooling tower or hot water supply. This case demonstrates the importance of detecting the infection source and carrying out environmental maintenance in cooperation with the infection control team. PMID:24462430

Osawa, Kayo; Shigemura, Katsumi; Abe, Yasuhisa; Jikimoto, Takumi; Yoshida, Hiroyuki; Fujisawa, Masato; Arakawa, Soichi

2014-01-01

265

Pilot-scale treatment and cooling tower reuse of gasification wastewater  

Energy Technology Data Exchange (ETDEWEB)

The principal goal of the gasification research program at the University of North Dakota Energy Research Center (UNDERC) is to develop environmental data for effluent streams for fixed-bed gasification processes using low rank coals (LRC). Current efforts involve the treatment of gas liquor wastewater streams, and subsequent reuse in process cooling towers. The relatively large volume of wastewater produced in the fixed-bed gasification of LRC's makes the reuse of this stream in an evaporative cooling tower a desirable approach. However, the use of gas liquor as cooling tower makeup presents both operating and environmental concerns. At UNDERC a series of cooling tower wastewater reuse tests have been performed using water pretreated to various degrees. Wastewater for each test was produced in a pilot slagging fixed-bed gasifier (SFBG) at UNDERC using North Dakota lignite from the Indian Head mine. During the first phase of testing SFBG wastewater was treated by solvent extraction and steam stripping, to reduce levels of phenolic compounds and ammonia, prior to use as makeup to a pilot mechanical draft cooling tower. In later tests, this extracted and stripped wastewater (SGL) was further treated by biological oxidation and by granular activated carbon adsorption in pilot equipment at UNDERC before being fed to the cooling tower. The final test in this series involved the use of this extensively treated wastewater with the addition of chemical corrosion and scale inhibitors as cooling tower makeup. High carbon steel corrosion rates, biological and organic fouling rates, foaming, and volatile organic stripping rates were observed in the test using stripped gas liquor from slagging fixed-bed gasification.

Galegher, S.J.; Mann, M.D.; Willson, W.G.; Mayer, G.G.; Hendrikson, J.G.

1985-03-01

266

The status and development prospects of cooling tower design from the point of view of various environmental effects  

International Nuclear Information System (INIS)

The manufacturers of wet and dry cooling towers are striving to develop plants for discharging waste heat into the atmosphere which are as operationally safe and favourable from the environmental point of view as possible. Using as an example plants which have been tendered and designed for water cooling, the paper indicates how the cooling tower design can be adapted to suit the particular environmental protection requirements of the location. (orig.)

267

Deformation and stability of wind loaded hyperbolic cooling tower shells  

Energy Technology Data Exchange (ETDEWEB)

Following the formulation of the deformation and stability problem on the basis of originally non-conforming triangular curved finite elements with the help of a variational principle with subsidiary conditions, the deformation problem is solved numerically for an existing cooling tower shell. The subsequent stability analysis of this cooling tower shell shows relatively good agreement of the buckling safety computed by means of the finite element method and the minimum of buckling safety obtained with the help of Mungan's stability criterion.

Mang, H.; Torcicky, P. (Technische Univ., Vienna (Austria). Inst. fuer Elastizitaet- und Festigkeitslehre); Gallagher, R.H. (Arizona Univ., Tucson (USA). Coll. of Engineering); Cedolin, L. (Politecnico di Milano (Italy). Istituto di Scienza e Tecnica delle Costruzioni)

1978-12-01

268

Cooling tower environmental impact prediction at inland nuclear power plant  

International Nuclear Information System (INIS)

As a heat dissipation system, natural-draft cooling tower is usually used for inland nuclear power plant. The waste heat of plant is transferred to atmosphere primarily by evaporating, which will bring out the potential adverse impacts,including visible plume, shadow of plume,ground deposition of drift droplet and noise. In this paper, the environmental impact prediction model of cooling tower, based on SACTI program recommended by NRC, was used to predict impacts of current three inland nuclear power sites (Hunan, Hubei and Anhui provinces). To illustrate the compatibility of SACTI in China, the prediction results were compared with GGNS power station in U.S. (authors)

269

Heat and mass transfer in natural draft cooling towers  

Science.gov (United States)

Cooling towers (CTs) are important units in the vast majority of power plants. They have been intensively investigated for the last 70 years. The abundance of works makes difficult to "see" the total area of investigations of CTs and to find the most urgent and important results. This article contains a compact overview of contemporary publications (for the last 11 years) in the area of heat and mass transfer in CTs, especially in natural draft wet cooling towers (NDWCT), and of related phenomena. Attention is specially paid to modern numerical computational investigations.

Kashani, M. M. Hemmasian; Dobrego, K. V.

2013-09-01

270

Design of cooling towers by the effectiveness-NTU method  

International Nuclear Information System (INIS)

This paper develops the effectiveness-NTU, number of transfer units, 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 transfer 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-NYU 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 Log-Mean Enthalpy Method (LMED) or effectiveness-NTU design methods to design cooling towers

271

Study of the comparative costs of five wet/dry cooling tower concepts  

Energy Technology Data Exchange (ETDEWEB)

The projected cost of five alternative dry/wet power plant heat rejection concepts was studied under conditions imposed by hypothetical use in association with the San Juan Plant Unit 3, a 550-MWe facility currently under construction near the ''Four Corners'' area of New Mexico. The five alternative concepts were: integrated dry/wet tower; separate dry and wet towers; metal fin-tube induced draft tower with deluge water augmentation; plastic heat exchanger tower with deluge water augmentation, and metal fin-tube/deluge augmentation tower with an intermediate ammonia evaporation-condensation condenser and the cooling tower. The integrated dry/wet tower concept, already chosen for service at San Juan Unit 3, was included for reference purposes. All concepts were conceptually designed and estimated using the same bases and employing uniform practices. Each concept was assumed to use all water allocated for consumptive use in Unit 3. The cost estimates obtained showed the following descending order of ''comparable capital cost'': separate dry/wet; metal fin-tube/deluge; integrated dry/wet; plastic tube/deluge; and metal fin-tube/deluge/ammonia. The results indicate that two of the advanced concepts considered, i.e., the plastic tube/deluge concept and the metal fin tube/deluge/ammonia concept, can possibly reduce the overall costs of dry/wet cooling under conditions imposed by the site considered. It was recommended that these two concepts receive additional attention by the ERDA Dry Cooling Tower Program and industry to further quantify their potential benefits and demonstrate their performance and reliability.

Zaloudek, F.R.; Allemann, R.T.; Faletti, D.W.; Johnson, B.M.; Parry, H.L.; Smith, G.C.; Tokarz, R.D.; Walter, R.A.

1976-09-01

272

Numerical analysis of crosswind effect on wet cooling tower aerodynamic field  

International Nuclear Information System (INIS)

Based on CFD code FLUENT, three-dimensional numerical analyses were carried out for natural draft wet cooling tower under crosswind conditions.Sensitivity analyses to parameters such as ambient crosswind velocity profile and water droplet equivalent diameter validated the adopted numerical model. The effect of crosswind on wet cooling tower inner and outer aerodynamic field and tower internal heat and mass transfer performance were investigated numerically. The results show that crosswind causes the increase of air inflow relative departure degree and induces horizontal air mass flow rate which improves rain zone heat and mass transfer but reduces tower vertical air mass flow rate, and then produces an unfavorable effect on fill zone and increases outflow water temperature. The analyses about air inflow relative departure degree show that improving the air inflow aerodynamic field can reduce the unfavorable effect of crosswind on the circumference distribution of air inlet air radial velocity and then improve the total cooling performance of wet cooling tower under crosswind conditions. (authors)

273

Performance prediction of wet cooling tower using artificial neural network under cross-wind conditions  

International Nuclear Information System (INIS)

This paper describes an application of artificial neural networks (ANNs) to predict the thermal performance of a cooling tower under cross-wind conditions. A lab experiment on natural draft counter-flow wet cooling tower is conducted on one model tower in order to gather enough data for training and prediction. The output parameters with high correlation are measured when the cross-wind velocity, circulating water flow rate and inlet water temperature are changed, respectively. The three-layer back propagation (BP) network model which has one hidden layer is developed, and the node number in the input layer, hidden layer and output layer are 5, 6 and 3, respectively. The model adopts the improved BP algorithm, that is, the gradient descent method with momentum. This ANN model demonstrated a good statistical performance with the correlation coefficient in the range of 0.993-0.999, and the mean square error (MSE) values for the ANN training and predictions were very low relative to the experimental range. So this ANN model can be used to predict the thermal performance of cooling tower under cross-wind conditions, then providing the theoretical basis on the research of heat and mass transfer inside cooling tower under cross-wind conditions. (authors)

274

Advanced wet--dry cooling tower concept performance prediction  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this year's work has been to test and analyze the new dry cooling tower surface previously developed. The model heat transfer test apparatus built last year has been instrumented for temperature, humidity and flow measurement and performance has been measured under a variety of operating conditions. Tower Tests showed approximately 40 to 50% of the total energy transfer as taking place due to evaporation. This can be compared to approximately 80 to 85% for a conventional wet cooling tower. Comparison of the model tower test results with those of a computer simulation has demonstrated the validity of that simulation and its use as a design tool. Computer predictions have been made for a full-size tower system operating at several locations. Experience with this counterflow model tower has suggested that several design problems may be avoided by blowing the cooling air horizontally through the packing section. This crossflow concept was built from the previous counterflow apparatus and included the design and fabrication of new packing plates. Instrumentation and testing of the counterflow model produced data with an average experimental error of 10%. These results were compared to the predictions of a computer model written for the crossflow configuration. In 14 test runs the predicted total heat transfer differed from the measured total heat transfer by no more than 8% with most runs coming well within 5%. With the computer analogy's validity established, it may now be used to help predict the performance of fullscale wet-dry towers.

Snyder, T.; Bentley, J.; Giebler, M.; Glicksman, L.R.; Rohsenow, W.M.

1977-01-01

275

Cooling tower and plume modeling for satellite remote sensing applications  

Energy Technology Data Exchange (ETDEWEB)

It is often useful in nonproliferation studies to be able to remotely estimate the power generated by a power plant. Such information is indirectly available through an examination of the power dissipated by the plant. Power dissipation is generally accomplished either by transferring the excess heat generated into the atmosphere or into bodies of water. It is the former method with which we are exclusively concerned in this report. We discuss in this report the difficulties associated with such a task. In particular, we primarily address the remote detection of the temperature associated with the condensed water plume emitted from the cooling tower. We find that the effective emissivity of the plume is of fundamental importance for this task. Having examined the dependence of the plume emissivity in several IR bands and with varying liquid water content and droplet size distributions, we conclude that the plume emissivity, and consequently the plume brightness temperature, is dependent upon not only the liquid water content and band, but also upon the droplet size distribution. Finally, we discuss models dependent upon a detailed point-by-point description of the hydrodynamics and thermodynamics of the plume dynamics and those based upon spatially integrated models. We describe in detail a new integral model, the LANL Plume Model, which accounts for the evolution of the droplet size distribution. Some typical results obtained from this model are discussed.

Powers, B.J.

1995-05-01

276

Assessing the environmental health relevance of cooling towers--a systematic review of legionellosis outbreaks.  

Science.gov (United States)

Bioaerosols from cooling towers are often suspected to cause community-acquired legionellosis outbreaks. Although Legionella infections can mostly be assigned to the emission sources, uncertainty exists about the release and distribution into the air, the occurrence of the respirable virulent form and the level of the infective concentration. Our study aimed to evaluate studies on legionellosis outbreaks attributed to cooling towers published within the last 11 years by means of a systematic review of the literature. 19 legionellosis outbreaks were identified affecting 12 countries. Recurring events were observed in Spain and Great Britain. In total, 1609 confirmed cases of legionellosis and a case-fatality rate of approximately 6% were reported. Duration of outbreaks was 65 days on average. For diagnosis the urinary antigen test was mainly used. Age, smoking, male sex and underlying diseases (diabetes, immunodeficiency) could be confirmed as risk factors. Smoking and underlying diseases were the most frequent risk factors associated with legionellosis in 11 and 10 of the 19 studies, respectively. The meteorological conditions varied strongly. Several studies reported a temporal association of outbreaks with inadequate maintenance of the cooling systems. A match of clinical and environmental isolates by serotyping and/or molecular subtyping could be confirmed in 84% of outbreaks. Legionella-contaminated cooling towers as environmental trigger, in particular in the neighbourhood of susceptible individuals, can cause severe health problems and even death. To prevent and control Legionella contamination of cooling towers, maintenance actions should focus on low-emission cleaning procedures of cooling towers combined with control measurements of water and air samples. Procedures allowing rapid detection and risk assessment in the case of outbreaks are essential for adequate public health measures. Systematic registration of cooling towers will facilitate the identification of the source of outbreaks and help to shorten their duration. PMID:24100053

Walser, Sandra M; Gerstner, Doris G; Brenner, Bernhard; Höller, Christiane; Liebl, Bernhard; Herr, Caroline E W

2014-03-01

277

ESTIMATION OF DOWNWIND VIABLE AIRBORNE MICROBES FROM A WET COOLING TOWER - INCLUDING SETTLING  

Science.gov (United States)

In recent years, reuse of municipal waste water as the coolant in drift-producing cooling towers at electrical generating plants has become increasingly common. A hueristic model is presented that can be used to estimate the concentrations of viable airborne microbes in the drift...

278

Optimization design of solar enhanced natural draft dry cooling tower  

International Nuclear Information System (INIS)

Highlights: • We proposed a cost model for solar enhanced natural draft dry cooling tower. • We proposed an optimization scheme for this new cooling system. • We optimally designed one for a 50 MW EGS geothermal plant as a demonstration. • Results proved its economic advantages for EGS geothermal application. - Abstract: This paper proposed an optimization scheme for solar enhanced natural draft dry cooling tower design, in which a detailed cost model was proposed including capital, labour, maintenance and operation costs of each component. Based on the developed cost model, the optimal design option can be identified in terms of the relatively lower annual cost and the relatively higher total extra income over the Solar Enhanced Natural Draft Dry Cooling Tower (SENDDCT) lifetime. As a case study, a SENDDCT was optimally designed to meet the cooling demand for a 50 MW geothermal power plant with Engineered Geothermal System (EGS) technology. The results showed that the optimized SENDDCT not only has better cooling performance during the daytime but also is a cost effective option for EGS geothermal power plants

279

Discussion on NPP cooling tower's load value according to British BS, German BTR and Chinese codes  

International Nuclear Information System (INIS)

Design of nuclear power plant cooling tower is a new task for NPP CI design. Requirements on NPP safety and utilization are different from those on common fossil-fired power plants and the design of cooling tower is an important aspect. Specifications on values of cooling tower design load in British BS, German BTR and Chinese codes (on hydraulic structures) are analyzed and compared. A few significant conclusions reached are helpful reference for NPP cooling tower design. (authors)

280

Application of mechanical draft cooling tower in inland nuclear power plants  

International Nuclear Information System (INIS)

This paper described the nuclear power plant related design criterion classification of mechanical draft cooling tower used in inland nuclear power plant ultimate heat-sink systems, analyzed and summarized the special design and construction requirements of nuclear-classified mechanical draft cooling tower, and brought forward the qualification procedure of equipment in such cooling tower, and finally proposed a reference and guide for the design and development of domestic nuclear-classified mechanical draft cooling tower. (authors)

 
 
 
 
281

Operational cost minimization in cooling water systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop const...

Castro M.M.; Song T.W.; Pinto J.M.

2000-01-01

282

Construction of a 146m height stay-structured cooling tower  

International Nuclear Information System (INIS)

Construction of cooling tower for 300 MW NPP with the THTR-300 type reactors has been described. Dry stay-structured cooling tower with capacity 31700 m3/hr is designed for water cooling from 38.4 to 26.5 deg C under the pressure of 10.1 kPa and at the environment temperature 12 deg C. The assessed period of operation is 50 years. The tower height is 146 m and the foundation diameter is 141 m. The construction is designed for wind loading exceeding by a factor of 1.5 the loading 1550 H/m2 in the areas of the smallest transverse cross section. Under the loading the fluidity limit, corresponding to relative elongation of element of 0.02%, will not be surpassed in any of the steel elements. A central ferroconcrete pylon 180 m high and 6.6 m in diameter serves as the tower support. One upper and two intermediate rings are suspended to the pylon by ropes. To the upper ring the stay-structured net is fixed, which is lined from the inner side with corrugated sheets 1 mm thick; the lining area is 38000 m2. As compared with conventional cooling towers the one described is less metal-consuming (approximately 30%), it is characterized by increased resistance of structure to wind and seismic loadings, increased plant completeness of its elements, and it can be erected not using cranes

283

Method of analysis and design of monolithic cooling tower shell at inhomogeneous foundation  

International Nuclear Information System (INIS)

The method of analysis and design of cooling tower shell at inhomogeneous foundation is proposed on the basis of FEM [finite element method] and probability theory. The proposed method also allows to evaluate the reliability of cooling tower at inhomogeneous foundation. The settling of the cooling towers lower edge may lead to increase of internal stresses and to an emergency

284

40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.  

Science.gov (United States)

...final coolers, and final-cooler cooling towers. 61.134 Section 61.134...final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions...final coolers and final-cooler cooling towers at coke by-product recovery...

2010-07-01

285

Economic and technical assessment of the desiccant wheel effect on the thermal performance of cross flow cooling towers in variable wet bulb temperature  

Science.gov (United States)

Performance improvements of cross flow cooling towers in variable wet bulb temperature were performed. A conventional mathematical model is used to predict desiccant wheel effect on the performance of cooling tower. It is found that by using optimum parameters of desiccant wheel, the inlet air wet bulb temperature into the cooling tower would decrease more than 6 °C and outlet water temperature would decrease more than 4 °C.

Banooni, Salem; Chitsazan, Ali

2014-05-01

286

Investigation on the impact of the environment wind velocity on the indirect air-cooling tower performance  

Science.gov (United States)

The wind velocity plays a crucial role in the operation characteristic of indirect cooling tower. In this paper a 2×330MW vertical arrangement indirect air-cooled system was taken as research object, and numerical simulation method was used to analyze the relative influence of the wind speed, ranging from 4m/s to 18m/s, on the outlet water temperature of cooling tower, the outlet air temperature of radiator, the facing wind speed of the fan segment and on the outlet air speed of the cooling tower. The result shows that the impact of the natural wind speed on the cooling tower efficiency varies greatly and this impact increases as the wind speed increases.

Qin, Yongbo; Gu, Hongfang; Wang, Haijun; Chen, Guoyong

2013-07-01

287

Recent developments in the design of large cooling towers  

International Nuclear Information System (INIS)

The growth of power plant units has initiated the development of very large cooling towers. The shell curvature of such towers is comparably small producing an increase of bending effects due to loads with a non-uniform distribution, such as turbulent wind pressures. The validity of the current concept of equivalent static wind loads is inspected. Some deficiencies may occur underrating the actual stresses. A simplified, quasi-static method of calculation is described including dynamic loading data obtained from wind-tunnel tests. (Author)

288

Seismic analysis and design of hyperbolic cooling towers  

International Nuclear Information System (INIS)

The safety of hyperbolic cooling towers is important to the continuous operation of a power plant. Depending upon the site, earthquake may govern the design of the tower. Methods of seismic analysis have been presented. It is concluded that the response spectrum method of analysis is of maximum practical use. A method to construct the design response spectra for various earthquake zones is presented. An earthquake motion consists of three components; however, it is shown that designing for one horizontal component only is adequate. The use of boundary conditions and the effects of inelastic action on analysis and design are discussed. (Auth.)

289

Cooling tower drift: experiment design for comprehensive case study  

International Nuclear Information System (INIS)

A drift experiment program to develop a data base which can be used for validation of drift deposition models has been formulated. The first field effort is designed for a suitable mechanical-draft cooling tower to be selected after site visits have been conducted. The discussion here demonstrates the importance of characterizing the droplet size spectrum emitted from the tower and to accurately account for droplet evaporation, because the downwind droplet deposition patterns and near-surface airborne concentrations are extremely sensitive to these parameters

290

Magnetic fluid conditioning system allows 3000 ppm hardness without cooling tower scale buildup  

International Nuclear Information System (INIS)

Big Three Industries, a manufacturer of compressed and liquefied atmospheric gases, operates a large production complex in Bayport, TX which recirculates 100,000 gpm cooling water. Due to regulatory agency guidelines, high costs, and limited effectiveness of conventional chemical treatment methods, Big Three was in need of a treatment method to prevent corrosion and scaling in recirculating water cooling systems. In December 1983 a magnetic fluid conditioner (MFC) was installed in the pump discharge piping of one cooling tower at Bayport. The patented MFC is an 18'' long spool pipe fitted with uranium-based alloy magnets. The MFC has no moving parts and requires no chemicals, external power source, or maintenance. The MFC is designed so that the fluid is accelerated through a magnetic field. The high velocity of the fluid causes nucleation of the salts in the fluid. The salts are separated from the water by precipitation. During eighteen months of using the MFC, the cooling tower has concentrated in excess of 50 cycles. Conductivity is in excess of 10,000 micromhos, and total hardness (CaCO3) is above 4000 ppm with pH stabilized between 8 and 9. However, inspections have revealed clean surfaces. The cleaner metal surfaces within the cooling water system provide better heat transfer which has resulted in reduction of tower blowdown, makeup water requirements, and pumping costs. Associated savings will enable the MFC to achieve payback in two and a half years

291

Geodesy work in the construction of cooling towers of the Temelin nuclear power plant  

International Nuclear Information System (INIS)

The specifications are described of the cooling tower foundations, the bottom part of the flue chimney and of the cooling tower casing. In view of the cooling tower configuration, the ground control points inside the tower were selected in the pit bottom and the layout and check were performed of the inner tower wall. The methodology of measuring the basic layout network, and of laying out up to the fiftieth (ca. 80 m) and from the 70th (106 m) strip is described. The measurement results are computer-processed. The accuracy is assessed of the cooling tower construction in the Temelin nuclear power plant. (E.J.). 1 fig., 5 refs

292

Evaluation of plume potential and plume abatement of evaporative cooling towers in a subtropical region  

International Nuclear Information System (INIS)

Hong Kong is a typical subtropical region with frequently high humidity in late spring and summer seasons. Plume from evaporative cooling towers, which service air-conditioning systems of civil buildings, has aroused public concerns since 2000 when the fresh water evaporative cooling towers were allowed to be used for high energy efficiency and environmental issues. This paper presents the evaluation of the plume potential and its effect on the sizing of the plume abatement system in a large commercial office building in Hong Kong for practical application. This evaluation was conducted based on a dynamic simulation platform using the typical meteorological year of Hong Kong since the occurrence of the plume heavily depends on the state conditions of the exhaust air from cooling towers and the ambient air, while the state condition of the exhaust air is determined by the total building cooling load and the control strategies of cooling towers employed mainly for improving energy efficiency. The results show that the control strategies have a significant effect on the plume potential and further affect the system design and sizing of the plume abatement system

293

Biocide usage in cooling towers in the electric power and petroleum refining industries  

Energy Technology Data Exchange (ETDEWEB)

Cooling towers users frequently apply biocides to the circulating cooling water to control growth of microorganisms, algae, and macroorganisms. Because of the toxic properties of biocides, there is a potential for the regulatory controls on their use and discharge to become increasingly more stringent. This report examines the types of biocides used in cooling towers by companies in the electric power and petroleum refining industries, and the experiences those companies have had in dealing with agencies that regulate cooling tower blowdown discharges. Results from a sample of 67 electric power plants indicate that the use of oxidizing biocides (particularly chlorine) is favored. Quaternary ammonia salts (quats), a type of nonoxidizing biocide, are also used in many power plant cooling towers. The experience of dealing with regulators to obtain approval to discharge biocides differs significantly between the two industries. In the electric power industry, discharges of any new biocide typically must be approved in writing by the regulatory agency. The approval process for refineries is less formal. In most cases, the refinery must notify the regulatory agency that it is planning to use a new biocide, but the refinery does not need to get written approval before using it. The conclusion of the report is that few of the surveyed facilities are having any difficulty in using and discharging the biocides they want to use.

Veil, J.; Rice, J.K.; Raivel, M.E.S.

1997-11-01

294

Prevalence of Legionella strains in cooling towers and legionellosis cases in New Zealand.  

Science.gov (United States)

Over 3,900 water samples from 688 cooling towers were tested for Legionella in 2008 in New Zealand. Of 80 (2.05% isolation rate) Legionella isolates, 10 (12.5%) were L. pneumophila serogroup 1; 10 (12.5%) were L. anisa; nine (11.2%) were L. pneumophila serogroup 8; and one (1.2%) was L. longbeachae serogroup 2. Forty-one (51.2%) Legionella isolates were L. pneumophila serogroups. Over 3,990 water samples from 606 cooling towers were tested for Legionella in 2009 in New Zealand. Of 51 (1.28% isolation rate) Legionella isolates, 18 (35.3%) were L. pneumophila serogroup 1, and 39 (76.4%) were other L. pneumophila serogroups. L. pneumophila serogroups were significantly associated with legionellosis cases in 2008 and 2009. L. longbeachae serogroups were equally significantly associated with legionellosis cases. This significant association of L. longbeachae with legionellosis particularly of L. longbeachae serogroup 1 is unique in that part of the world. The authors' study also showed that the aqueous environment of the cooling tower is not a natural habitat for pathogenic L. longbeachae. Regular monitoring and maintenance of cooling towers have prevented outbreaks of legionellosis. PMID:23397654

Lau, Robert; Maqsood, Saadia; Harte, David; Caughley, Brian; Deacon, Rob

2013-01-01

295

Anomalous snowfall caused by natural-draft cooling towers  

International Nuclear Information System (INIS)

Scattered reports of significant amounts of snow anomalously produced by cooling-tower plumes suggest that this process may be of importance. This conclusion is supported by study of high-resolution satellite images. Tabulation of a number of aerial observations of plumes at subfreezing temperatures indicates that a plume is likely to produce measurable snow if its temperature is colder than -130C and the saturation deficit of the ambient air is less than 0.5 g m-3. These factors are important because they affect the rates of nucleation and growth of ice particles. The rate of mixing between plume and ambient air is also important because it affects the rate of evaporation within the plume, which in turn determines the length of time available for snow particles to grow large enough to fall out. These empirically derived criteria were tested using a numerical model of cloud microphysics that simulates the most important processes of transfer of water substance between vapor, liquid, and ice, including nucleation and development of particle-size spectra. Dynamic processes were specified, not modeled. Among the many quantities computed is the flux density of snow at the base of the plume. From this, together with average fallspeed and horizontal wind speed, one can compute the amount and pattern of snowfall at the ground

296

Study on Characteristics of Special Turbine in Hydrodynamic Cooling Tower  

Directory of Open Access Journals (Sweden)

Full Text Available Today a special type of hydraulic turbine is used to replace electromotor to drive the fan in hydrodynamic cooling tower. This is a brand new turbine application. At present, systematic researching about the special turbine has still not been seen. The energy consumption of the electromotor is saved entirely because the power source comes from the surplus energy of circulating water system. But the special turbine works in a series of pressure flow system, its flow characteristic, working characteristics and regulative characteristics different from conventional power turbine. This study introduces the theory analysis and experimental study on these characteristics. The research shows that special turbine has more complex flow characteristics and the turbine-fan unit has good self-adaptive characteristics and regulative characteristics. When the turbine is not in its optimal condition we can regulate it to a proper condition by adjusting the guide glade and the angle of the fan's vane or replacing the diameter of fan. These are never been found.

Li Yanpin

2012-11-01

297

Types of dry/wet cooling tower cells  

International Nuclear Information System (INIS)

The author reports preliminary experience with two hybrid test cooling towers in cellular design in the Gemeinschaftskernkraftwerk Neckar (GKN) with a view to technology and influence on the plumes. Depending on the occurrence of different plume-determining parameters, remarkable plume reductions have been observed as well as situations without noticeable improvement. The findings, which are ambiguous, indicate the necessity of systematic analytical investigations. (orig.)

298

A numerical study of interacting buoyant cooling-tower plumes  

Energy Technology Data Exchange (ETDEWEB)

The compact design of mechanical cooling towers necessitates that the plumes are issued into the cross-wind in close proximity. An improved understanding of the interaction of adjacent plumes is therefore required for better design of such cooling towers, which may lead to a reduction in their environmental impact. This paper presents the results of a numerical investigation into the interaction of two adjacent plumes in a cross-flow. The numerical model simulates small-scale wind tunnel experiments of a cooling tower arrangement. The computations are performed for three-dimensional, turbulent, buoyant and interacting plumes, and for a single plume for comparison. Two double-source arrangements, namely, tandem and side-by-side, with respect to the oncoming atmospheric boundary layer are considered. A low Reynolds number k-{epsilon} turbulence model is used with two discretisation schemes, hybrid and QUICK, and the results are compared. Comparisons are also made with the experimental results. The results show that the interaction of side-by-side plumes is dominated by the interaction of the rotating vortex pairs within the plumes. A tandem source arrangement leads to early merging and efficient rise enhancement. Comparisons of the predicted results with experimental data show good agreement for the plume rise. (Author)

Bornoff, R.B.; Mokhtarzadeh-Dehghan, M.R. [Brunel Univ., Uxbridge (United Kingdom). Dept. of Mechanical Engineering

2001-07-01

299

A numerical study of interacting buoyant cooling-tower plumes  

Science.gov (United States)

The compact design of mechanical cooling towers necessitates that the plumes are issued into the cross-wind in close proximity. An improved understanding of the interaction of adjacent plumes is therefore required for better design of such cooling towers, which may lead to a reduction in their environmental impact. This paper presents the results of a numerical investigation into the interaction of two adjacent plumes in a cross-flow. The numerical model simulates small-scale wind tunnel experiments of a cooling tower arrangement. The computations are performed for three-dimensional, turbulent, buoyant and interacting plumes, and for a single plume for comparison. Two double-source arrangements, namely, tandem and side-by-side, with respect to the oncoming atmospheric boundary layer are considered. A low Reynolds number k- ? turbulence model is used with two discretisation schemes, hybrid and QUICK, and the results are compared. Comparisons are also made with the experimental results. The results show that the interaction of side-by-side plumes is dominated by the interaction of the rotating vortex pairs within the plumes. A tandem source arrangement leads to early merging and efficient rise enhancement. Comparisons of the predicted results with experimental data show good agreement for the plume rise.

Bornoff, R. B.; Mokhtarzadeh-Dehghan, M. R.

300

MATHEMATICAL MODEL FOR MULTIPLE COOLING TOWER PLUMES  

Science.gov (United States)

A mathematical model is developed for the prediction of plume properties such as excess plume temperature, humidity and liquid phase moisture (water droplet), plume trajectory, width, and dilution at the merging locations and the beginning and ending points of the visible part of...

 
 
 
 
301

Vibration Analysis of a Cooling Fan Gear Reducer of the Secondary Cooling Tower in HANARO  

International Nuclear Information System (INIS)

HANARO is an open-tank-in-pool-type Korean research reactor that generates 30MW of thermal power. It differs from power plant reactor in that the heat generated by HANARO is exhausted into the atmosphere through a secondary cooling tower, thus maintaining the core temperature constant. During every monthly inspection of the cooling tower, large vibrations that exceeded the permissible limit were observed at cooling fan gear reducer No. 4 of the cooling tower. The purpose of this study is to identify the origin of the large vibration and to repair it. FFT spectrum analysis is performed to identify the part that caused the large vibration. The results of the frequency analysis showed that the vibration frequency was 354 Hz, which is twice the natural frequency of the pinion gear. A check of the pinion gear revealed that there was a crack on the surface of the pinion gear. After the gear was replaced, the reducer operated normally

302

A high vibration analysis for a cooling fan of the secondary cooling tower in HANARO  

International Nuclear Information System (INIS)

HANARO, an open-tank-in-pool type research reactor of 30 MWth power in Korea, which is different from a power plant reactor, exhausts a fission heat generated from the reactor core into the atmosphere through a secondary cooling tower instead of an electric power production from the heat. During every one month inspection of the cooling tower, a No. 4 cooling fan gear reducer of the cooling tower recoded a high unstable vibration above the limit. To find the reason, a frequency analysis was conducted. It was conformed through the results of the frequency analysis that the frequency of the high vibration was 354 HZ which was calculated two times rotation of the pinion gear of the gear reducer. There was a broken of the gear surface of the pinion gear transferred the rotation power. After the repair of the pinion gear, the reducer was operated normally.

303

The quantity of algae colonizing the inside face of cooling towers and the consequences for wear of the shell  

International Nuclear Information System (INIS)

These studies are part of the interdirectorate working group's mandate relating to lifespan project on cooling towers. Involving the collaboration of several divisions of Electricity de France: the Construction Division (SEPTEN). The Generation and Transmission Division (SPT) and the Research and Development Division (EAA). Among the biological colonies which proliferate in the cooling circuits of power stations, algae are broadly represented in the form of wall coatings which cover the inside face of cooling towers: shell algae. They can also grow at other points in the cooling circuit; in the cold water basin, in the fill, and, in some cooling towers, in the hot water basin. These plant organisms hamper the operation of power stations by clogging the grids located in the pipe from the cold water basin to the condenser. In addition, when algae come free of the shell, they remove micro-fragments of the concrete, which could accelerate wear. This paper presents the findings of studies conducted by the Aquatic and Atmospheric Department on the infestation of cooling towers by algae. In particular, the results of studies to evaluate the quantity of algae on the inside face of the shell of cooling towers. Many scenarios will be proposed, linked to the operation of the plant and to the local meteorological conditions

304

Operational cost minimization in cooling water systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are [...] considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.

M.M., Castro; T.W., Song; J.M., Pinto.

2000-12-01

305

Operational cost minimization in cooling water systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.

Castro M.M.

2000-01-01

306

Cementitious stabilization of chromium, arsenic, and selenium in a cooling tower sludge  

International Nuclear Information System (INIS)

The Federal Facility Compliance Agreement (FFCA) establishes an aggressive schedule for conducting studies and treatment method development under the treatability exclusion of RCRA for those mixed wastes for which treatment methods and capabilities have yet to be defined. One of these wastes is a radioactive cooling tower sludge. This paper presents some results of a treatability study of the stabilization of this cooling tower sludge in cementitious waste forms. The sample of the cooling tower sludge obtained for this study was found to be not characteristically hazardous in regard to arsenic, barium, chromium, lead, and selenium, despite the waste codes associated with this waste. However, the scope of this study included spiking three RCRA metals to two orders of magnitude above the initial concentration to test the limits of cementitious stabilization. Chromium and arsenic were spiked at concentrations of 200, 2,000, and 20,000 mg/kg, and selenium was spiked at 100, 1,000, and 10,000 mg/kg (concentrations based on the metal in the sludge solids). Portland cement, Class F fly ash, and slag were selected as stabilizing agents in the present study. Perlite, a fine, porous volcanic rock commonly used as a filter aid, was used as a water-sorptive agent in this study in order to control bleed water for high water contents. The highly porous perlite dust absorbs large amounts of water by capillary action and does not present the handling and processing problems exhibited by clays used for bleed water control

307

Pilot-scale treatment of gasification wastewater and reuse in a cooling tower  

Energy Technology Data Exchange (ETDEWEB)

The University of North Dakota Energy Research Center has operated a 910 kg/hr, oxygen-blown fixed-bed gasifier to produce lignite-derived effluents for characterization, treatment, and reuse studies. Reuse of waste water in a cooling tower was investigated to define environmental and process effects as a function of pretreatment. The gasification wastewater was pretreated in pilot wastewater treatement units which simulate available technology. During the first phase of the program, wastewater was pretreated by solvent extraction and steam stripping to produce phenol and ammonia concentrations comparable to those expected at the Great Plains Gasification Associates plant. This pretreated wastewater was concentrated in a cooling tower to 10 cycles of concentration. No biocides or corrosion inhibitors were added. Severe fouling of heat exchange surfaces and high corrosion rates of carbon steel were encountered. Over 90% of the phenol entering the cooling tower was found to be stripped into the cooling tower exhaust air stream. The high levels of organics remaining in this minimally treated wastewater suggested that further biological treatment and possibly polishing by carbon adsorption would be necessary to prepare a satisfactory feed. In the second phase of the program, the SGL was further treated in an activated sludge process followed by granular activated carbon adsorption. Biotreatment removed 96% of the BOD with a three-day retention time while obtaining satisfactory sludge settling rates in spite of varied influent concentrations. Biorefractory materials were adsorbed on GAC to reach an effuent COD level of 150 mg/l. This upgrading was sufficient to reduce organic emissions from the cooling tower, but corrosion rates were higher than in the previous test, again showing the necessity for corrosion inhibitors. 8 figs., 3 tabs.

Willson, W.G.; Mayer, G.G.; Hendrikson, J.G.; Winton, S.L.

1985-04-01

308

NONWATER QUALITY IMPACTS OF CLOSED-CYCLE COOLING SYSTEMS AND THE INTERACTION OF STACK GAS AND COOLING TOWER PLUMES  

Science.gov (United States)

The report gives results of a literature survey of the nonwater quality impacts of closed-cycle cooling systems. Following discussions of cooling tower and stack gas plumes, interactions of these plumes are considered. For cooling tower plumes, plume types, behavior, salt drift g...

309

Local precipitation increases caused by scavenging of cooling tower plumes  

International Nuclear Information System (INIS)

Quantitative estimates are provided of the precipitation increase in the vicinity of wet cooling towers as a result of plume-droplet scavenging by natural rain. Rain rates from 1 to 5 mm/hr and wind speeds of 1 to 10 m/s are considered with source strength equal to moisture flux from a 1000-MW(e) power capacity. The increase in precipitation strongly depends on distance from the tower, wind speed, natural precipitation rate, source strength, and horizontal angle of plume spread. Under favorable conditions of light winds and steady rainfall, precipitation increases due to scavenging up to about 25 percent of the natural rate should occur as far as 1 km from plants as small as 1000 MW

310

Advanced wet-dry cooling tower concept cross-flow tests  

Energy Technology Data Exchange (ETDEWEB)

The design, operation, instrumentation, and performance testing of a crossflow evaporative cooling tower are discussed, and computer predictions for performance are compared with test data. Experimental results for 14 runs agreed with heat and mass transfer coefficient calculations within 5% for 11 runs and within 8% for the remaining 3 runs. It was concluded that the computer model is valid for use in future design studies, that the wet-dry packing is effective in reducing cooling water consumption, and that the crossflow air-water arrangement shows much promise for future development. (LCL)

Snyder, T.; Bentley, J.; Giebler, M.; Glicksman, L.R.; Rohsenow, W.M.

1977-01-01

311

N3S-AERO. A multidimensional model for numerical simulation of flows in cooling towers  

International Nuclear Information System (INIS)

In order to obtain a better estimation of thermal efficiency as well as a good description of local phenomena in cooling towers, a specific version of EDF's industrial finite element code N3S, denoted N3S-AERO, has been developed for the simulation of flows in cooling towers. It allows to model obstructed zones by directional head losses tensors and fans using their characteristic curves. A single model might include up to 20 towers (with their components - e.g. anti-freeze system - and their environmental exterior domain) in al kinds of configuration (counter flows with recuperators or with rain zones, cross flows, or any combination). The present paper describes the governing equations for air and water flows as well as the numerical algorithms used. Validation is carried out on some configurations of cooling tower in 2D and 3D geometries, showing the ability of N3S-AERO to predict major physical phenomena. Global results on thermal performance are compared with results of the 1D code TEFERI or experimental data when available. Further validation is underway to achieve finer comparison with experimental data for large industrial configurations. (author)

312

The Worlds First Ever Cooling Tower Acceptance Test Using Process Data Reconciliation  

International Nuclear Information System (INIS)

The cooling capacity of cooling towers is influenced by multiple constructive and atmospheric parameters in a very complex way. This leads to strong variations of the measured cold-water temperature and causes unacceptable unreliability of conventional acceptance tests, which are based on single point measurements. In order to overcome this lack of accuracy a new approach to acceptance test based on process data reconciliation has been developed by BTB Jansky and applied at a nuclear power plant. This approach uses process data reconciliation according to VDI 2048 to evaluate datasets over a long period covering different operating conditions of the cooling tower. Data reconciliation is a statistical method to determine the true process parameters with a statistical probability of 95% by considering closed material-, mass-and energy balances. Datasets which are not suitable for the evaluation due to strong transient gradients are excluded beforehand, according to well-defined criteria. The reconciled cold-water temperature is then compared, within a wet bulb temperature range of 5 deg. C to 20 deg. C to the manufacturer's guaranteed temperature. Finally, if the average deviation between reconciled and guaranteed value over the evaluated period is below zero, the cooling tower guarantee is fulfilled. (authors)

313

Greenhouse gas reduction from fossil fuel power stations the effect of surface condenser and cooling tower performance  

Energy Technology Data Exchange (ETDEWEB)

Surface condenser and cooling tower performance impact directly on the efficiency of power generation, and therefore greenhouse gas emission, from fossil fuel power stations. If performance can be maintained at close to design or original levels, both power generation costs and greenhouse gases will be minimized. The cooling water management and cooling tower operation required to achieve peak performance are not high capital items, and in fact are normally an existing operating cost. Algorithms were used to generate a mathematical model for greenhouse gas emission reduction as a function of fuel type and the surface condenser and cooling tower performance indicators, namely, cleanliness factor and inlet cooling water temperature, respectively. The model was run under typical power station conditions with brown coal, back coal and natural gas to generate two reduction factors, one for an increase in cleanliness factor from 70% to 95%, the other for a 12{sup o}C drop in cooling water temperature due to improved cooling tower performance. The combined impact of operating surface condensers and their associated cooling towers at the improved performance levels is close to 1% reduction in CO{sub 2} equivalent emissions for all three of the fossil fuels considered. While not a large reduction per se, it is large relative to a power station's viable greenhouse gas reduction options. Tables and graphs are presented to allow greenhouse gas emission reductions to be estimated for any selection of surface condenser or cooling tower performance improvement. The impact and cost benefit of other greenhouse gas reduction strategies and technologies are discussed. 12 refs., 3 figs., 9 tabs.

NONE

2006-07-01

314

Experience with the operation during winter of wet cooling towers with a varied concept of the main cooling system  

International Nuclear Information System (INIS)

On the basis of experience gained from cooling towers in operation it is prudent to operate 'in advance' new cooling towers in accordance with the load and air temperature to be expected. Experience during winter operation, which influences the design of new installations, has been accumulated from the cooling towers at Philippsburg and Grohnde nuclear power stations and also from those at the district heating power plant of Volkswagen at Wolfsburg. The measures taken cannot and should not totally prevent ice formation; however, with future expected methods of operation of cooling towers it is possible to foresee uninterrupted operation during winter. (orig.)

315

Numerical simulation of shower cooling tower based on artificial neural network  

International Nuclear Information System (INIS)

This study was prompted by the need to design towers for applications in which, due to salt deposition on the packing and subsequent blockage, the use of tower packing is not practical. The cooling tower analyzed in this study is void of fill, named shower cooling tower (SCT). However, the present study focuses mostly on experimental investigation of the SCT, and no systematic numerical method is available. In this paper, we first developed a one dimensional model and analyzed the heat and mass transfer processes of the SCT; then we used the concept of artificial neural network (ANN) to propose a computer design tool that can help the designer evaluate the outlet water temperature from a given set of experimentally obtained data. For comparison purposes and accurate evaluation of the predictions, part of the experimental data was used to train the neural network and the remainder to test the model. The results predicted by the ANN model were compared with those of the standard model and the experimental data. The ANN model predicted the outlet water temperature with a MAE (mean absolute error) of 1.31%, whereas the standard one dimensional model showed a MAE of 9.42%

316

Fire analog: a comparison between fire plumes and energy center cooling tower plumes  

International Nuclear Information System (INIS)

Thermal plumes or convection columns associated with large fires have been compared to thermal plumes from cooling tower systems to evaluate the fire analog concept. Energy release rate of mass fires is generally larger than that of single or small groups of cooling towers but may be comparable to proposed large energy centers. However, siginficant physical differences exist between cooling tower and fire plumes. Cooling tower plumes are usually dominated by ambient wind and turbulence conditions. Fire plumes, depending on fire intensity and area, can transform into free convection energy systems resulting in convective columns, strong inflow and updrafts, turbulence and concentrated vortices. Since these characteristics have not been observed with cooling tower plumes to date, the fire analog concept is questionable at this time. Additional research is needed on fire and cooling tower plumes

317

Seismic response analysis of column supported natural draught cooling tower shells  

International Nuclear Information System (INIS)

Natural draught cooling towers (NDCTs) belong to the category of large civil engineering structures and are commonly used in nuclear or thermal power plants. Detailed dynamic analysis has to be carried out for design of cooling towers subjected to seismic excitation, considering the flexibility of the columns. Finite ring element formulations for dynamic analysis of cooling tower shell subjected to seismic excitation are presented in this paper. The geometry of a typical tall natural draught cooling tower is considered in this study for carrying out investigations. Transient response of the hyperbolic cooling tower shell subjected to earthquake loading has been analysed by direct time integration using acceleration-time history of North-South component of El-Centro earthquake. Parametric studies have also been carried out to study the influence of flexibility of column supports and damping on the seismic response of cooling tower shell and the results are discussed in the paper. (author)

318

The Merkel equation revisited: A novel method to compute the packed height of a cooling tower  

International Nuclear Information System (INIS)

Highlights: ? A relationship between packed height and excess air flow rate is derived. ? The relationship is independent of tower diameter and water flow rate. ? It is well approximated by a power law curve for industrially relevant cases. ? An algorithm to compute the thermodynamic minimum air flow rate is detailed. ? Computation of the packed height is simplified especially for design-optimization. - Abstract: In this work, a new methodology of analysis and computation is presented which simplifies calculation of the packed height in a counter current cooling tower, especially for design and cost optimization studies. An algorithm is presented with an implementation in MATLAB to compute the thermodynamic minimum air flow rate for the desired cooling. Combining the Merkel equation and a standard empirical mass transfer correlation, the packed height is shown to be independent of the water flow rate and tower diameter, and dependent only on the excess air flow. The relationship is unique for a given cooling range of water and inlet air wet bulb temperature. A simple power law regression is used to approximate this relationship and results are presented for Vertical Corrugated Packing.

319

Physical quantities related to measurement campaigns for cooling towers  

International Nuclear Information System (INIS)

The nomenclature in reports on the measurement campaigns for cooling towers will be adapted as far as possible to the already existing VDI report on this subject. On the other hand, the appropriate standards will also be accounted for. In order to facilitate a decision in individual cases in a first table the meteorologically or generally interesting quantities of the VDI reports are compared with the German, international, and WMO standards and - if necessary - also commented. A second table contains the air humidity parameters standardized by WMO including brief definitions. (orig/HP)

320

Wind induced vibrations of reinforced concrete cooling tower shells  

International Nuclear Information System (INIS)

Natural draught cooling towers are shell structures subjected to random vibrations due wind turbulence. The random response may be analyzed using a spectral approach nad assuming a linear elastic behaviour of the structure. Coupling between the different modes of vibration has to be taken into account. The excitation is given in terms of spectra and cross-spectra of the pressure fluctuations on the shell surface which are related to the spectrum of wind turbulence. The results show in particular that the resonant part of the response remains small even under unfavourable conditions. (Author)

 
 
 
 
321

Wind pressure distribution in a hyperbolic cooling tower  

International Nuclear Information System (INIS)

Results of a wind tunnel study of the wind pressure distribution on a hyperbolic cooling tower 133m high and base diameter of 122m are prese nted. Measurements of wind pressure were made at 16 external and 8 internal levels. The base columns as well as the heat exchangers were reproduced in the model. The heat exchanger caused a small alteration on the overall distribution of the external and internal pressures, with the exception of the region on the wake near the shell bottom where the internal suction was substantially smaller in the model without heat exchanger. (Author)

322

Noise radiation from natural-draft cooling towers for nuclear power plants  

International Nuclear Information System (INIS)

A procedure for computing the noise levels in the vicinity of natural-draft cooling towers is presented. The noise levels are computed in overall and octave band levels with A-weighting and with no weighting. Attenuation of the noise by wave spreading, atmospheric absorption, barrier screening, vegetation, and wind and temperature gradients are included. The procedure is applied to a nuclear power plant served by four cooling towers and to a nuclear energy center with forty cooling towers

323

Cooling water systems performance evaluations  

International Nuclear Information System (INIS)

All nuclear power station cooling water systems are required to transfer heat from both safety and non-safety related structures, systems, and components to the ultimate heat sink (UHS). Examples of an UHS include rivers, lakes, cooling ponds, or cooling towers. Cooling water systems are designed and analyzed to meet minimum system performance requirements by delivering required flows to components based on a specific UHS temperature. If the maximum UHS temperature or any minimum flow limits are violated, the design basis on the safety related portion of the system or component could be exceeded, and the assumptions used in the plant safety analyses could be invalidated. The authors' company has completed programs which have been successfully implemented at several nuclear power stations to raise the design basis UHS temperature and to establish cooling water system flow requirements and flow capacities. This paper addresses the evaluation of cooling water system performance and its degradation and presents lessons learned from the implementation of these programs

324

A method to estimate the ageing of a cooling tower  

International Nuclear Information System (INIS)

This paper deals with cooling towers ageing. Our contribution is a method to determine which part of on site measured strain we are able to predict by means of simulations. As a result, we map a gap indicator on the structure. Calculations have been performed in three configurations. Comparing the values obtained in the three cases helps to determine which researches are worth to be done. Indeed, gap indicator reveals that: - THM can not be considered as the main and only ageing mechanism, so long as tower older than 10 years are examined. At least creep has to be taken into account too; - Gap indicator is sensitive to initial hydration conditions. Drying process before bringing into service should be estimated properly, taking into account the different construction steps; - Comparing different thermal conditions reveals that meteorological conditions have a significant influence on results. So, it will be interesting to differentiate the sunny and the shaded part of the tower when the measurements are done; - A large part of the values obtained can be explicated by construction defects. A study on this particular problematic seems to be essential. The four items mentioned must be considered as perspectives to improve the present method of simulations. (authors)

325

Reuse of refinery's tertiary-treated wastewater in cooling towers: microbiological monitoring.  

Science.gov (United States)

The study was planned to quantify the distribution of bacteria between bulk water and biofilm formed on different materials in an industrial scale cooling tower system of an oil refinery operating with clarified and chlorinated freshwater (CCW) or chlorinated tertiary effluent (TRW) as makeup water. The sessile and planktonic heterotrophic bacteria and Pseudomonas aeruginosa densities were significantly higher in the cooling tower supplied with clarified and chlorinated freshwater (CTCW) (p?towers, the biofilm density was higher on the surface of glass slides and stainless steel coupons than on the surface of carbon steel coupons. The average corrosion rates of carbon steel coupons (0.4-0.8 millimeters per year (mpy)) and densities of sessile (12-1.47?×?10(3) colony-forming unit (CFU)?cm(-1)) and planktonic (0-2.36?×?10(3) CFU mL(-1)) microbiota remained below of the maximum values of reference used by water treatment companies as indicative of efficient microbial control. These data indicate that the strategies of the water treatment station (WTS) (free chlorine) and industrial wastewater treatment station (IWTS) followed by reverse electrodialysis system (RES) (free chlorine plus chloramine) were effective for the microbiological control of the two makeup water sources. PMID:25226836

Dos Santos, Vera Lúcia; Veiga, Andréa Azevedo; Mendonça, Rafael Silva; Alves, Andrea Lima; Pagnin, Sérgio; Santiago, Vânia M J

2014-09-17

326

Demineralised water cooling in the LHC accelerator  

CERN Document Server

In spite of the LHC accelerator being a cryogenic machine, it remains nevertheless a not negligible heat load to be removed by conventional water-cooling. About 24MW will be taken away by demineralised water cooled directly by primary water from the LHC cooling towers placed at the even points. This paper describes the demineralised water network in the LHC tunnel including pipe diameters, lengths, water speed, estimated friction factor, head losses and available supply and return pressures for each point. It lists all water cooled equipment, highlights the water cooled cables as the most demanding equipment followed by the radio frequency racks and cavities, and by the power converters. Their main cooling requirements and their positions in the tunnel are also presented.

Peón-Hernández, G

2002-01-01

327

Heat rejection enhancement in natural draft cooling tower using radiator-type windbreakers  

International Nuclear Information System (INIS)

Highlights: • Radiator-type windbreakers are more efficient than solid types. • They can improve cooling efficiency by three times of solid types. • Radiator-type windbreakers are efficient even at normal condition. - Abstract: Cooling efficiency of a natural draft dry cooling tower decreases under crosswind condition. Many researchers frequently recommended solid windbreakers to improve the cooling efficiency. The present research work concerns with the cooling performance assessment of the cooling tower under crosswind condition when the windbreakers are fabricated from the same type of cooling tower radiators. Computational fluid dynamics approach based on the finite volume method has been used to assess the cooling performance of the cooling tower. Numerical results show that radiator type windbreakers can substantially more improve the cooling efficiency than the usual solid types do

328

Analysis of the new cooling tower in Šoštanj on temperature action  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this graduation thesis, the influence of temperature action on the new cooling tower in Šoštanj is analyzed. The temperature load is defined according to guideline VGB-R 610 e, izdaja 2010.In the first part of work, general specifications of the new cooling tower in Šoštanj are presented. The plot of the shell of the cooling tower by using Mathematica is given. In second part of thesis we determine temperature action on the new cooling tower in Šoštanj according to VGB-R 610 e, izdaj...

S?abec, Tomaz?

2013-01-01

329

Effect of column length on buckling factors of R.C. hyperbolic cooling towers  

International Nuclear Information System (INIS)

In this research, the bucking of R.C. cooling towers of Shazand power plant as a typical cooling tower has been studied by using VGB recommendations due to wind load. Infinite element analysis ANSYS 5.4 was used. The effect of columns on global buckling of the R.C. cooling towers has been ignored in most codes of practices except ACI. According to this research, in cooling towers with long columns, not only the buckling factors decrease considerably but in the first modes the columns buckle instead of the shell

330

Three-dimensional numerical study on thermal performance of a super large natural draft cooling tower of 220m height  

Science.gov (United States)

Based on the heat and mass transfer theory and the characteristics of general-purpose software FLUENT, a three-dimensional numerical simulation platform, composed of lots of user defined functions(UDF), has been developed to simulate the thermal performance of natural draft wet cooling towers(NDWCTs). After validation, this platform is used to analyse thermal performances of a 220m high super large cooling tower designed for inland nuclear plant under different operational conditions. Variations of outlet temperature of the cooling tower caused by changes of water flow rates, inlet water temperatures are investigated. Effects of optimization through non-uniform water distributions on outlet water temperature are discussed, and the influences on the flow field inside the cooling tower are analyzed in detail. It is found that the outlet water temperature will increase as the water flow rate increases, but the air flow rate will decrease. The outlet water temperature will decrease 0.095K and 0.205K, respectively, if two non-uniform water distribution approaches are applied.

Jin, Tai; Zhang, Li; Luo, Kun; Fan, Jianren

2013-06-01

331

Optimization of mechanical draft counter flow wet-cooling tower using artificial bee colony algorithm  

International Nuclear Information System (INIS)

Research highlights: ? ABC algorithm is used for optimization of counter flow wet-cooling tower. ? Minimizing the total annual cost for specific heat duty is the objective function. ? Six examples are presented to demonstrate the effectiveness of the proposed algorithm. ? The results are compared with the results of GAMS optimization package. ? The ABC algorithm can be modified to suit optimization of other thermal systems. -- Abstract: This study explores the use of artificial bee colony (ABC) algorithm for design optimization of mechanical draft counter flow wet-cooling tower. Minimizing the total annual cost for specific heat duty requirement is considered as objective function. Three design variables such as water to air mass ratio, mass velocity of water and mass velocity of air are considered for optimization. Evaluations of the cooling tower geometry and performances are based on an adaptive version of Merkel's method. Temperature and enthalpy constraints are included in the optimization procedure. Six examples are presented to demonstrate the effectiveness and accuracy of the proposed algorithm. The results of optimization using ABC are validated by comparing with those obtained by using GAMS optimization package. The effect of variation of ABC parameters on the convergence and optimum value of the objective function has also been presented.

332

Towards safe and economic seismic design of cooling towers of extreme height  

International Nuclear Information System (INIS)

Nuclear power plants are being increasingly equipped with natural draught cooling towers of heights greater than 160 m. In many arid zones, where high natural draught cooling towers with dry cooling systems are being projected, wind loads are relativelly small while site seismicity is relatively high. Thus the ability of the tower to withstand earthquake induced forces governs its design. On the other hand, most reinforced concrete cooling towers of extreme height built so far were designed to withstand high wind loads and moderate earthquake loads. The effects of special structural measures for obtaining an economic design, such as the introduction of ring stiffened shells, have been studied mainly for those towers. In view of the previous aspects it is the purpose of this paper to analyze the effects of various structural measures and other parameters on the seismic response of such high cooling towers. (orig.)

333

Effects of inlet relative humidity and inlet temperature on the performance of counterflow wet cooling tower based on exergy analysis  

International Nuclear Information System (INIS)

The purpose of this study is to analyze the influence of the ambient temperature and humidity on the performance of a counterflow wet cooling tower according to the second law, exergy analysis, of thermodynamics. First, the properties of water and air flow through the tower were predicted and validated by the experiment. Exergy analysis then has been carried out for investigating the cooling tower performance with various inlet air conditions, relative humidity and dry bulb temperature, while the water side condition is kept constant. According to the analysis in this paper, the similar result in terms of required dry air flow rate, exergy change of water and that of air, exergy destruction and second law efficiency were obtained for the various inlet air conditions. The exergy change of water ?xw is higher than that of air ?xair, since ?xw is the available energy of water to supply to air throughout the tower while ?xair is the available energy of air to recover or utilize that supplied by water. It reveals that ?xair is dominated by the exergy change of air due to evaporative heat transfer. In addition, it gives a clearer explanation of the cooling tower performance and gives clear trends for optimization

334

Emission of asbestos fibres from natural-draught cooling towers. Pt. 1 and 2  

International Nuclear Information System (INIS)

Sampling for the studies reported has been done in a relatively new nuclear power plant with natural-draught, wet cooling tower, and in an older, brown-coal fired power plant with the same type of cooling towers, both towers equipped with internal structures made of asbestos cement. Samples have been taken from the plumes, air in the environment, cooling water receiving tank, make-up water. The samples have been primarily examined for their content of asbestos fibres. The results show that relatively few asbestos is found in the environmental air and in the cooling water receiving tank. Putting it continuously, it can be said that the cooling water entrains only little amounts of the asbestos of the internal structures. The plume samples indicate emission of some thousand asbestos fibres per m3, or less than 1 ng. Taking into account one sample exhibiting an extremely high amount of asbestos, the average emission of asbestos fibres with the plumes is 106 fibres per m3, or 100 ng/m3 of plume. The maximum air pollution thus calculated in accordance with TA Luft (Clean Air Technical Directive), for the less favourable weather conditions at a hight of 2 m above ground, is 10 fibres per one m3 of air; including the extreme data of the single sample mentioned above, the result is some thousand fibres per m3. The data are far below the TRK data (Technical guiding data for maximum concentration at the place of work), which state a maximum of 106 fibres per m3. (orig.)

335

Use of treated gasification wastewater in a pilot cooling tower. Phase I. Final report for the period ending January 31, 1984  

Energy Technology Data Exchange (ETDEWEB)

During the UNDERC cooling tower tests, data were colleced and evaluated in five major areas: characterization of cooling tower streams, process performance, biofouling, corrosion, and inorganic/organic fouling. A summary of the results and conclusions for each area is presented. Recommendations are provided for research and development programs to further define the pretreatment and operating requirements for the use of wastewater as cooling tower makeup. The results of the Phase I-Pilot Cooling Tower test have revealed several potential problems that may arise from the use of a relatively high organic content gas liquor as cooling tower makeup. Most of the problems identified are related to the presence of organics in the wastewater which promote biofouling/fouling, corrosion, and emissions from the cooling tower. The Phase II-Pilot Cooling Tower Test will address this issue by identifying the advantages of further treatment of stripped gas liquor to reduce the organic content to a lower level before use in the cooling tower. This test will parallel the Phase I test using the same system and monitoring procedures. Comparison of the results of Phase I and Phase II tests will provide an indication of how well problem areas can be avoided with additional makeup water pretreatment. 39 references, 34 tables, and 25 figures.

Willson, W.G.; Hendrikson, J.G.; Mann, M.D.; Galegher, S.J.; Gallagher, J.R.; Mayer, G.G.; Thomas, W.C.; Winton, S.L.; Nelson, D.F.

1984-05-16

336

Study plan for conducting a section 316(a) demonstration: K-Reactor cooling tower, Savannah River Site  

International Nuclear Information System (INIS)

The K Reactor at the Savannah River Site (SRS) began operation in 1954. The K-Reactor pumped secondary cooling water from the Savannah River and discharged directly to the Indian Grave Branch, a tributary of Pen Branch which flows to the Savannah River. During earlier operations, the temperature and discharge rates of cooling water from the K-reactor were up to approximately 70 degree C and 400 cfs, substantially altering the thermal and flow regimes of this stream. These discharges resulted in adverse impacts to the receiving stream and wetlands along the receiving stream. As a component of a Consent Order (84-4-W as amended) with the South Carolina Department of Health and Environmental Control, the Department of Energy (DOE) evaluated the alternatives for cooling thermal effluents from K Reactor and concluded that a natural draft recirculating cooling tower should be constructed. The cooling tower will mitigate thermal and flow factors that resulted in the previous impacts to the Indian Grave/Pen Branch ecosystem. The purpose of the proposed biological monitoring program is to provide information that will support a Section 316(a) Demonstration for Indian Grave Branch and Pen Branch when K-Reactor is operated with the recirculating cooling tower. The data will be used to determine that Indian Grave Branch and Pen Branch support Balanced Indigenous Communities when K-Reactor is operated with a recirculating cooling tower. 4 refs., 1 fig. 1 tab

337

Analysis, synthesis and optimization of complex cooling water systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cooling water systems are used to remove excess heat from a chemical process to the atmosphere. The primary components of these systems are the cooling tower and the heat exchanger network. There is a strong interaction between these individual components, thus their performances are interrelated. Most published research in this area has focused mainly on optimization of the individual components i.e. optimization of heat exchanger network or optimization of the cooling towers. This approach ...

Gololo, Khunedi Vincent

2013-01-01

338

COMPARISON OF MODEL PREDICTIONS AND CONSUMPTIVE WATER USE OF CLOSED CYCLE COOLING SYSTEMS  

Science.gov (United States)

The report gives results of a comparison of field-data-derived water evaporation rates with predictive model values for cooling towers and cooling ponds at steam-electric generating plants. The Leung Moore cooling tower model and five cooling pond models (Harbeck and Marciano; Ha...

339

Thermodynamic study of the effects of ambient air conditions on the thermal performance characteristics of a closed wet cooling tower  

International Nuclear Information System (INIS)

A thermodynamic model was developed and used to assess the sensitivity of thermal performance characteristics of a closed wet cooling tower to inlet air conditions. In the present study, three cases of different ambient conditions are considered: In the first case, the average mid-winter and mid-summer conditions as well as the extreme case of high temperature and relative humidity, in Athens (Greece) during summer are considered according to the Greek Regulation for Buildings Energy Performance. In the second case, the varied inlet air relative humidity while the inlet air dry bulb temperature remains constant were taken into account. In the last case, the effects on cooling tower thermal behaviour when the inlet air wet bulb temperature remains constant were examined. The proposed model is capable of predicting the variation of air thermodynamic properties, sprayed water and serpentine water temperature inside the closed wet cooling tower along its height. The reliability of simulations was tested against experimental data, which were obtained from literature. Thus, the proposed model could be used for the design of industrial and domestic applications of conventional air-conditioning systems as well as for sorption cooling systems with solid and liquid desiccants where closed wet cooling towers are used for precooling the liquid solutions. The most important result of this theoretical investigation is that the highest fall of serpentine water temperature and lossesof serpentine water temperature and losses of sprayed water are observed for the lowest value of inlet wet bulb temperature. Hence, the thermal effectiveness, which is associated with the temperature reduction of serpentine water as well as the operational cost, which is related to the sprayed water loss due to evaporation, of a closed wet cooling tower depend predominantly on the degree of saturation of inlet air.

340

Experimental analysis of heat and mass transfer phenomena in a direct contact evaporative cooling tower  

International Nuclear Information System (INIS)

This paper deals with an experimental analysis of simultaneous heat and mass transfer phenomena between water and air by direct contact in a packed cooling tower. The tower is filled with a 'VGA.' (Vertical Grid Apparatus) type packing. The packing is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross-sectional test area of 0.15 m x 0.148 m. This study investigates the effect of the air and water flow rates on the global heat and mass transfer coefficient as well as the evaporation rate of water into the air stream, for different inlet water temperatures. Two operating regimes were observed during the air/water contact inside the tower, a Pellicular Regime (PR) and a Bubble and Dispersion Regime (BDR). These two regimes can determine the best way to promote the heat and mass transfer phenomena in such device. The BDR regime seems to be more efficient than the Pellicular Regime, as it enables to achieve relatively higher values of the global heat and mass transfer coefficient and larger water evaporation rates. The comparison between the obtained results and some of those available in the literature for other types of packing indicates that this type possesses good heat and mass transfer characteristics.

 
 
 
 
341

Experimental analysis of heat and mass transfer phenomena in a direct contact evaporative cooling tower  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with an experimental analysis of simultaneous heat and mass transfer phenomena between water and air by direct contact in a packed cooling tower. The tower is filled with a ''VGA.'' (Vertical Grid Apparatus) type packing. The packing is 0.42 m high and consists of four (04) galvanised sheets having a zigzag form, between which are disposed three (03) metallic vertical grids in parallel with a cross-sectional test area of 0.15 m x 0.148 m. This study investigates the effect of the air and water flow rates on the global heat and mass transfer coefficient as well as the evaporation rate of water into the air stream, for different inlet water temperatures. Two operating regimes were observed during the air/water contact inside the tower, a Pellicular Regime (PR) and a Bubble and Dispersion Regime (BDR). These two regimes can determine the best way to promote the heat and mass transfer phenomena in such device. The BDR regime seems to be more efficient than the Pellicular Regime, as it enables to achieve relatively higher values of the global heat and mass transfer coefficient and larger water evaporation rates. The comparison between the obtained results and some of those available in the literature for other types of packing indicates that this type possesses good heat and mass transfer characteristics. (author)

Lemouari, M. [Department of Processes Engineering, Faculty of Sciences and Engineering, University of Bejaia (Algeria); Boumaza, M. [Department of Chemical Engineering, College of Engineering - King Saud University, P.O. Box 800, Riyadh (Saudi Arabia); Kaabi, A. [Department of Genie Climatique, Faculty of Engineering, University of Constantine, Constantine (Algeria)

2009-06-15

342

Reuso de efluentes em torres de resfriamento - estudo conceitual: Aeroporto Internacional do Rio de Janeiro = Water reuse for cooling towers – conceptual study: Rio de Janeiro International Airport  

Directory of Open Access Journals (Sweden)

Full Text Available O reuso de água é ferramenta valiosa na gestão da água, que promove a otimização da utilização do recurso desta, que reduz e, muitas vezes, até elimina os impactos no meio ambiente. Neste trabalho foi investigada a composição do efluente secundário da estação de tratamento de efluentes (ETE APOIO do Aeroporto Internacional do Rio de Janeiro, com o objetivo de propor o processo adequado à reutilização deste efluente como água de reposição nas torres de resfriamento desse Aeroporto. Com base nas análises de cátions, ânions, DBO e DQO, verificou-se o parâmetro SDT - Cl- como crítico para processamento do efluente. Foi proposta uma sequência para reutilização do efluente que continha o tratamento de osmose inversa, o custo do m3 produzido por essa sequência foi estimado em R$ 2,90 m-3. Water reuse is an important tool in water management; it is a conceptthat promotes optimization of the water resource, reducing and often even eliminating environmental impacts. In this work, the composition of a secondary effluent (from the effluent treatment station (ETE APOIO at Rio de Janeiro International Airport was analyzed, with theaim of determining an adequate process for the reutilization of this effluent as replacement cooling water. Chemical analyses such as cation and anion analysis, BOD and COD were performed. Based on these analyses, it was found that TDS - Cl- was the critical parameter foreffluent processing. A treatment system was proposed for effluent reuse including reverse osmosis; the cost estimate per m3 produced by this system was R$ 2.90 m-3.

Denize Dias de Carvalho

2010-07-01

343

Wind effects on optimal aerodynamic conditions for a wet cooling tower with natural draft  

International Nuclear Information System (INIS)

Among the problems of an aerodynamic nature, related to the wind action, the two following ones have to be studied through model tests to reach a better knowledge of design and operating conditions of counterflow natural draft wet cooling towers with water recovery systems. - Wind effects on performance. A very general phenomenon. In order to minimize this alteration, a common idea is to install radio windbrake walls. - Wind effects on the forces applied to the internal structures and thermal components. A relatively elaborate model, representative of a lower plenum layout was fitted with a sufficiently large number of pressure tapes to draw up the distribution of the pressure acting upon: - the packing, - the water recovery system, - the windbrake walls (eventually) and for various combination of these elements. The air flow mode in the tower was also observed. All these observations were made with different wind directions. This study showed that the forces were very variable geographically, very sensitive to the layout

344

Solving the heat transfer in the cold rain of a cross flow cooling tower. N3S code - cooling tower release  

International Nuclear Information System (INIS)

A simplified model for heat and mass transfer in the lower rainfall of a counter-flow cooling toward had to be implemented in the N3S code-cooling tower release It is built from an old code: ZOPLU. The air velocity field is calculated by N3S. The air and water temperature fields are solved by a Runge-Kutta method on a mesh in an adequate number of vertical plans. Heat exchange and drags correlations are given. And all the necessary parameters are specified. All the subroutines are described. They are taken from ZOPLU and modified in order to adapt their abilities to the N3S requirements. (author). 6 refs., 3 figs., 3 tabs., 3 appends

345

PERFORMANCE EVALUATION OF THE BRAINTREE ELECTRIC LIGHT DEPARTMENT DRY COOLING TOWER  

Science.gov (United States)

The report gives results of a 5-year evaluation of the performance of a dry cooling tower for the 20-MW steam-electric generation portion of an 85-MW combined-cycle power plant. Objectives of the study were to: demonstrate dry cooling tower technology at a Massachusetts seacoast ...

346

Successful implementation of ageing management exemplified at the cooling tower of Emsland nuclear power plant  

International Nuclear Information System (INIS)

The present paper describes the successful implementation of the restoration of water-distribution channels at the cooling tower of the Emsland nuclear power plant under the aspect of ageing management. The main challenge of aging management is the determination of potential aging mechanism and to avoid systematically and effectively their damaging influences. In the course of the annual site inspections abnormalities at the lower side of the water-distribution channels of the cooling tower were detected, analysed, and repaired. The extraordinary high chlorine equivalent of the cooling water was identified as main reason of the damages located. Due to extensive infiltration into the concrete structure, chloride-induced corrosion generates a volume expansion of the reinforcement and thereby to a blast off of the concrete covering. According to the restoration concept, the damaged concrete was removed by maximum pressure water jet blasting; where necessary the reinforcement was retrofitted and a layered concrete substitution was applied by synthetic cement mortar. The realised procedures conserve the load bearing reinforcement only for a certain period, because the permanent chloride infiltration could not be stopped. Therefore, the structure has to be monitored permanently. (orig.)

347

Analysis Of Cooling Tower Performance From Safety Factor Of Kartini Reactor Operation  

International Nuclear Information System (INIS)

Analysis of cooling tower performance from power generation of Kartini reactor has been done. The data's was observed with cooling tower coupled by plate and cylinder type heat exchanger. The Kartini reactor operated with nominal power at 100 k W during 24 hours and environmental data's observation have been done in ever 2 hours, Analysis and calculation used by Number of diffusion Unit and Enthalpy Balance Method to find NDU parameter. The NDU parameter is value heat transfer processing in cooling tower system. The NDU parameter used to find of safety factor and maintenance schedule of cooling tower. From analysis and calculation resulted value of NDU operation under of NDU design and performance of cooling tower is safe

348

Concept of CFD model of natural draft wet-cooling tower flow  

Science.gov (United States)

The article deals with the development of CFD model of natural draft wet-cooling tower flow. The physical phenomena taking place within a natural draft wet cooling tower are described by the system of conservation law equations along with additional equations. The heat and mass transfer in the counterflow wet-cooling tower fill are described by model [1] which is based on the system of ordinary differential equations. Utilization of model [1] of the fill allows us to apply commonly measured fill characteristics as shown by [2].The boundary value problem resulting from the fill model is solved separately. The system of conservation law equations is interlinked with the system of ordinary differential equations describing the phenomena occurring in the counterflow wet-cooling tower fill via heat and mass sources and via boundary conditions. The concept of numerical solution is presented for the quasi one dimensional model of natural draft wet-cooling tower flow. The simulation results are shown.

Hyhlík, T.

2014-03-01

349

Cooling tower plume rise analyses by airborne lidar  

Science.gov (United States)

As part of the Atmospheric Studies in Complex Terrain (ASCOT) program, five cooling-tower plume experiments were conducted at The Geysers geothermal area in California during August 1981. The experiments were designed to investigate plume behavior during conditions of valley nocturnal drainage flow and daytime vertical mixing on a mountain ridge. The Airborne Lidar Plume and Haze Analyzer (ALPHA-1) system was used during the experiments to observe plume geometry and aerosol structure of the boundary layer. Subvisible plume rise derived from the backscatter signatures is related to visible plume-rise results recently published. This analysis indicates that the lidar-observed plumes are about 10 times higher than visually observed plumes. The lidar-observed plume rise seemed to correspond with heights of elevated aerosol layers that typically indicate presence of temperature inversions. Pictorial displays are presented which provide information on atmospheric behavior over mountainous terrain.

Uthe, Edward E.

350

Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant  

International Nuclear Information System (INIS)

The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant

351

Girassol, Riser Towers for ultra deep water  

Energy Technology Data Exchange (ETDEWEB)

This is a brief presentation of the technical concept developed by ALTO MAR GIRASSOL (AMG) for the Girassol umbilical and flowlines system. In 1998 AMG was awarded a contract by Elf Exploration Angola for the engineering, procurement, construction and installation (EPCI) of the umbilical and flowline system. The technical concept is based around the use of sealine bundles and self-supporting hybrid riser towers which carry the production, water injection, gas injection, gas lift and service lines. The items discussed are: (1) selected field layout, (2) seabed flowlines, hybrid riser system, umbilicals, export lines, installation plan and overall project schedule.

Rougier, Regis

1999-07-01

352

Numerical simulation of flow field in cooling tower of passive residual heat removal system of HTGR  

International Nuclear Information System (INIS)

Environmental wind will influence the working conditions of natural convection cooling tower. The velocity and temperature fields in the natural convection cooling tower of the HTGR residual heat removal system at different environmental wind velocities were numerically simulated. The results show that, if there is no wind baffle, the flow in the cooling tower is blocked when environmental wind velocity is higher than 6 m/s, residual heat can hardly be removed, and when wind velocity is higher than 9 m/s, the air even flow downwards in the tower, so wind baffle is very necessary. With the wind baffle installed, the cooling tower works well at the wind speed even higher than 9 m/s. The optimum baffle size and positions are also analyzed. (authors)

353

Cooling towers: design and performance (citations from the Engineering Index Data Base). Report for 1970-August 1978  

International Nuclear Information System (INIS)

Abstracts from worldwide research on design and performance of mechanical draft and natural draft wet, dry, and dry-wet combination cooling towers are discussed. Citations cover studies on size reduction, corrosion protection, and economic optimization of cooling towers primarily used with nuclear power plants and fossil fuel power plants. A few abstracts pertain to cooling towers used in wastewater treatment

354

Cooling tower for industrial installations such power stations  

International Nuclear Information System (INIS)

The hot water cooler has a large structure over which the hot water flows, spread from dispersers above, with a collecting basin below for the cooled water. Air is drawn laterally over the cooler structure from outside to the interior. The structure transverse vertical horizontal top section efficiency decreases from outer to inner, whilst the bottom section efficiency profile is reversed. The intermediate section averages between the two. 2 figs

355

Building concept of cooling towers for WWER-1000 nuclear power plants  

International Nuclear Information System (INIS)

A project is described of cooling towers with natural draught for the Temelin nuclear power plant. The concept proceeds from the classical design of the so-called Itterson type, i.e., the outer cladding of the draught stack is made of a monolithic reinforced concrete unit in the shape of a hyperboloid of revolution supported by a system of oblique supports mounted along the edge of the cooled water tank. The procedure is explained of the thermal calculation for the given operating conditions. The basic alternatives are considered of the choice of material and design of the cooling system. Questions are discussed relating to the design of the eliminator, the windwart wall and the shape of the shell of the draught stack and its loading by wind and seismic effects. (E.S.)

356

Proximity of the home to a cooling tower and risk of non-outbreak Legionnaires' disease.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVE--To study the source of non-outbreak legionnaires' disease, particularly the role of cooling towers, by comparing the locations of patients' homes in relation to the location of cooling towers. DESIGN--Retrospective, descriptive study of a case series of patients with legionnaires' disease ill between 1978 and 1986 and, for comparison, a case series of patients with lung cancer. A prospectively developed register and interview based survey provided data on the location of cooling to...

Bhopal, R. S.; Fallon, R. J.; Buist, E. C.; Black, R. J.; Urquhart, J. D.

1991-01-01

357

Penelitian Kinerja Induced Draft Cooling Tower Dengan Potongan Pipa PVC Ø 1 Inci Sebagai Filling Material  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Filling material is a component that influence the performance of a cooling tower, where the contact surface and period between water and air are extended. One of the best forms of fill is the inclined-honeycomb form that is made from PVC lamellas which the price is quite expensive. The aim of this research is to find a new filling material with reliable effectiveness and affordable cost. The filling material itself was made from stacks of chopped PVC pipe with the size of ؽ...

Nasution, Dian Morfi

2011-01-01

358

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Du Xueping; Yin Yantao; Zeng Min; Yu Pengqing; Wang Qiuwang; Dong Zhaoyi; Chen Yitung

2014-01-01

359

Concept of CFD model of natural draft wet-cooling tower flow  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The article deals with the development of CFD model of natural draft wet-cooling tower flow. The physical phenomena taking place within a natural draft wet cooling tower are described by the system of conservation law equations along with additional equations. The heat and mass transfer in the counterflow wet-cooling tower fill are described by model [1] which is based on the system of ordinary differential equations. Utilization of model [1] of the fill allows us to apply commonly measured f...

Hyhlík T.

2014-01-01

360

Cooling tower symposium 1977. Kuehlturm-Symposium 1977. Theorie - Konstruktion - Bauausfuehrung  

Energy Technology Data Exchange (ETDEWEB)

Natural draft cooling towers are structures remarkable in many ways. They are extremely large shell structures, mainly affected by the wind load. It is above all the aerodynamic effects that have to be taken into account in cooling tower design. Their construction also differs in many ways from the construction of other buildings or structures and, finally, they are an unused-to sight in the landscape. The topics dealt with in this issue correspond to the lectures presented to the KIB symposium of 1977, giving a survey of the state-of-the-art at that time of cooling tower design and construction.

1977-01-01

 
 
 
 
361

Maintenance of cooling towers following two outbreaks of Legionnaires' disease in a city.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This survey assessed the maintenance of evaporative cooling towers in Glasgow, following two Legionnaires' disease outbreaks. Information was obtained from 76 of 81 premises and a maintenance score was calculated for each of 174 towers. The quality of maintenance was extremely varied (range of maintenance scores, 8-30; mean, 22 (S.D., 5.0); median, 23; maximum possible, 33) and some towers were neglected. Breaches of maintenance principles were mainly structural and organizational, e.g. inade...

Bhopal, R. S.; Barr, G.

1990-01-01

362

Report on accompanying measurements concerning the investigation into micro-organism discharge from the cooling tower facility of the Isar nuclear power plant  

International Nuclear Information System (INIS)

The report gives the thermal marginal conditions for micro-organism discharge measurements which, on the whole, are very similar throughout the whole period of time. Parameters i.e. meteorology, temperatures of cooling water at cooling-tower entry and exit, temperature of the liquid-water loads of the plumes as well as mass flows of the cooling water are needed for allocating microbiological measurements. Measurement of droplet discharge can be used for checking guaranteed value. (DG)

363

Structural inspection and wind analysis of redwood cooling towers at the Portsmouth Gaseous Diffusion Plant  

International Nuclear Information System (INIS)

As part of the plant upgrade program, structural analyses and field inspections were performed on four redwood cooling towers at the DOE Portsmouth gaseous diffusion plant located in Piketon, Ohio. The cooling towers are categorized as important hazard facilities. The loadings are derived from UCRL-15910 according to the pertinent hazard category. In addition to the seismic and wind loadings, the wood cooling towers are constantly subject to adverse environmental effects such as elevated temperature, chemical attack, icing and snow load, and motor vibrations. A thorough structural evaluation for all load combinations was performed for each of the cooling towers based on the structural code requirements of the Cooling Tower Institute and National Forest Products Association. Most stress criteria are unique for the redwood material. This evaluation was performed using finite element techniques on the global structural integrity and supplemented by hand calculations on the individual connection joints. Overloaded wood structural members and joints are identified by the analysis. The rectangular tower structure sits on a concrete basin that span across 60 ft by 200 ft. A major part of the cooling towers upgrading program involved field inspections of the individual cells of each tower. The primary purpose of these inspections was to identify any existing structural damage or deficiencies such as failed members, degraded wood, and deficiencies resulting from poor constructdeficiencies resulting from poor construction practice. Inspection of 40 cells identified some generic deficiencies that mostly are consistent with the analytical finding. Based on the analysis, some effective but inexpensive upgrading techniques were developed and recommended to bring the cooling towers into compliance with current DOE requirements

364

Cooling towers for combined cycles: New developments to meet environmental requirements  

Science.gov (United States)

Two new developments in dry cooling systems are presented: the single row condenser (SRC) finned tube and the natural draft air-cooled condenser (NDC). The SRC tube is a flat finned tube based on a technology used for compact heat exchangers. This tube was specifically developed for vacuum air-cooled condensers. The serpentine fins of the SRC tube could be made in aluminum or in galvanized steel. The special technique of the brazing of the aluminum fins is described. A technical and economical comparison is made between the classical dry cooling equipment and the NDC. This comparison concludes with the high economic interest in combining the NDC and the single row design. The mechanical draught wet cooling towers with plume abatement are introduced and compared to classical parallel hybrid and reduced plume towers. The environmental impact of wet cooling towers is discussed with regard to heat and mass transfer, plume, bulkiness, and noise.

Vouche, M.; Bouton, F.; Lemmens, P.

365

Comparison between wind and solar effects on static stresses in natural draught cooling tower  

International Nuclear Information System (INIS)

A thermal simulation of a cooling tower shell under sunshine was carried out. The associated constraints are virtually isotropic and change signs from one side of the shell to the other. The comparison with a schematic study of wind plus inherent weight shows that the thermal constraints are in the order of one third of the maximum constraints. The results presented correspond to the structure of a proposed 1300 MW type cooling tower 165 metres high

366

Research on the Flow-Head Characteristics of the Turbine Driving Fan in Cooling tower  

Directory of Open Access Journals (Sweden)

Full Text Available The flow-head characteristics of the special turbine in cooling tower are very different from the general power turbines’. This study has analyzed the former theoretically and proposed the theoretical formula of the head-flow. At the same time, the paper has studied the characteristics of the flow-head using the CFD method. The tests results have proved the principle of the flow-head of the turbine in cooling tower.

Li Yanpin

2012-11-01

367

Research on the Flow-Head Characteristics of the Turbine Driving Fan in Cooling tower  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The flow-head characteristics of the special turbine in cooling tower are very different from the general power turbines’. This study has analyzed the former theoretically and proposed the theoretical formula of the head-flow. At the same time, the paper has studied the characteristics of the flow-head using the CFD method. The tests results have proved the principle of the flow-head of the turbine in cooling tower.

Li Yanpin; Ren Yan; Zhang Lanjin; Chen Dexin

2012-01-01

368

Geodetic works on the construction of cooling tower of TEŠ 6  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis discusses with geodetic works on the construction of cooling tower of sixth block in Šoštanj thermal power plant. It presents briefly the thermal power plant and describes the process of construction of the cooling tower. The establishment of basic surveying network stakeout is explained. It is also contains a full description of the stakeout procedures. Paper states the requirements and accuracy of stakeout and describes practical examples. It shows the concrete implementatio...

Kolaric?, Andrej

2014-01-01

369

Methodology for evaluation of cooling tower performance - Part 1: Description of the methodology  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} New methodology for evaluation of CT performance is presented. {yields} It enables to study impacts of local irregularities in CT on plant's power output. {yields} Poppe model for applications on the local basis of CTs is presented. {yields} Empirical model connecting cooling water temperature with power output is derived. {yields} Study is based on measured data from a plant and natural draft CT. - Abstract: A methodology for the evaluation of a natural draft cooling tower (CT) that is a part of a power plant is proposed. In this work the connection between CT performance and power output is established. The methodology consists of three subparts, i.e. Cooling Tower Profiler (CTP) method, CT model and model of a power plant. In the first part of the paper the three subparts of the methodology are described. Focus is given to the empirical model of the plant and a new application of the Poppe model. The simple empirical model enables accurate prediction of the power increase as a function of cooling water temperature and load to the plant. On the other hand, Poppe governing equations were derived for application on the local basis of CT. Moreover, the constraints and assumptions of CT analysis are discussed. The methodology is presented on real data from the power plant and CT. This is the base for application of the methodology presented in the second part of the paper where the focus is given on minimizing the error of the methodology. A small area with irregularities is analyzed and results are reported. Furthermore, a simplified computational approach to solving the Poppe equations is proposed yielding faster calculation with preserved accuracy.

Smrekar, J., E-mail: jure.smrekar@uis.no [Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, 4036 Stavanger (Norway); Kustrin, I.; Oman, J. [Department of Power Engineering, University of Ljubljana, Askerceva 6, SI-1000 Ljubljana (Slovenia)

2011-10-15

370

Controlling the shape of cooling towers in the construction of the Temelin nuclear power plant  

International Nuclear Information System (INIS)

Eight reinforced concrete shell-type cooling towers with natural draught in the shape of a hyperboloid of revolution were designed for the Temelin nuclear power plant. The tower structure is very sensitive to shape deviations. Calculations confirmed that, e.g., a small alteration in the tower radius from the ideal shape significantly changes the state of stress. A new procedure was designed for measuring the cooling tower shape using electronic equipment from Wild company. Briefly discussed are preliminary results of the measurement of deviations of the top edges of shuttering plates prior to and after concreting. The maximum deviation was 46 mm. It is shown that using the new method, it will be possible to build a tower with tolerances satisfying not only the requirements of the project design but also much more stringent requirements of IASS recommendations. (Z.M.). 5 figs., 4 refs

371

A coherent set of design and control means for large wet cooling towers  

International Nuclear Information System (INIS)

Electricite de France operates, or has under construction, thirty large cooling towers for the 900, 1300 and 1400 MW nuclear power units. A review is given of the various problems posed by the design and control of these towers, as well as a description of the means employed (computer codes, test-benches, control methods and on-site measurement) to resolve them: global optimization of the power unit heat sink, cooling tower thermal design, shell design and calculation principles, hydraulic sizing, thermal operation study, vapor plume calculation, noise emission calculation and performance control. A bibliography of the main reports published on these subjects is given

372

Site and design temperature related economics of nuclear power plants with evaporative and non-evaporative cooling tower systems  

International Nuclear Information System (INIS)

A comprehensive cost and evaluation study is presented which has been conducted for nuclear power plants using cooling systems which employ either evaporative or non-evaporative cooling tower types. The primary purpose of the study is to develop the economics for two 1000 MW(e) light water reactor power plants, one built on a site requiring non-evaporative cooling, the other built on a site where sufficient water is available to support the requirements of evaporative cooling systems. The study, while specific to two sites selected in New York State by the New York State Energy Research and Development Authority, is also of a general nature so that it may be applied to other locations. It takes into account essential variables such as ambient temperature, water availability, water cost, railway and highway accessibility, proximity to electric load centers, and normal ecological restraints specific to the two sites

373

A new practical index for calcium carbonate scale prediction in cooling tower systems  

International Nuclear Information System (INIS)

Some calcium carbonate scaling indexes are shown to be ineffective an inaccurate in concentrated cooling tower water at pH levels above 7.5. In addition, there is a misunderstanding by many water treatment vendors on the use of the indexes. This has resulted in confusion by both end-users and vendors. More importantly, these indexes are shown to be inaccurate and ineffective for calcium carbonate scale prediction. This paper reviews many of the available indexes, the basis for their calculations, how they compare, and which are effective in cooling water systems. The development of a new index was started over 10 years ago and has been verified in operating systems. Since most cooling water treatment programs now operate at a pH level above 7.5 and as high as 9+, the index provides a more accurate and practical estimation of calcium carbonate scaling tendencies. Case histories are provided to show a comparison with other indexes, such as the Ryznar and Langelier indexes

374

Optimization of water-cooled chiller system with load-based speed control  

International Nuclear Information System (INIS)

This study investigates the energy performance of chiller and cooling tower systems integrated with variable condenser water flow and optimal speed control for tower fans and condenser water pumps. Thermodynamic-behaviour chiller and cooling tower models were developed to assess how different control methods of cooling towers and condenser water pumps influence the trade-off between the chiller power, pump power, fan power and water consumption under various operating conditions. Load-based speed control is introduced for the tower fans and condenser water pumps to achieve optimum system performance. With regard to an example chiller system serving an office building, the optimal control coupled with variable condenser water flow could reduce the annual system electricity use by 5.3% and operating cost by 4.9% relative to the equivalent system using constant speed fans and pumps with a fixed set point for cooling water temperature control

375

Genotypic variability and persistence of Legionella pneumophila PFGE patterns in 34 cooling towers from two different areas.  

Science.gov (United States)

Genotypic variability and clonal persistence are important concepts in molecular epidemiology as they facilitate the search for the source of sporadic cases or outbreaks of legionellosis. We studied the genotypic variability and persistence of Legionella pulsed-field gel electrophoresis (PFGE) patterns over time (period > 6 months) in 34 positive cooling towers from two different areas. In area A, radius of 70 km, 52 indistinguishable PFGE patterns were differentiated among the 27 cooling towers. In 13 cooling towers we observed >or= 2 PFGE patterns. Each cooling tower had its own indistinguishable Legionella PFGE pattern which was not shared with any other cooling tower. In area B, radius of 1 km, 10 indistinguishable PFGE patterns were obtained from the seven cooling towers. In four, we observed >or= 2 PFGE patterns. Three of these 10 indistinguishable PFGE patterns were shared by more than one cooling tower. In 27 of 34 cooling towers the same PFGE pattern was recovered after 6 months to up to 5 years of follow-up. The large genotypic diversity of Legionella observed in the cooling towers aids in the investigation of community outbreaks of Legionnaires' disease. However, shared patterns in small areas may confound the epidemiological investigation. The persistence of some PFGE patterns in cooling towers makes the recovery of the Legionella isolate causing the outbreak possible over time. PMID:18199124

Sanchez, Inma; Garcia-Nuñez, Marian; Ragull, Sonia; Sopena, Nieves; Pedro-Botet, Maria Luisa; Estere, Maria; Rey-Joly, Celestino; Sabria, Miquel; Esteve, Maria

2008-02-01

376

Findings of the research project on bacterial emissions from cooling towers  

International Nuclear Information System (INIS)

The extend of germ emissions has been determined in a wide-ranged study on four wet cooling towers (during different seasons), and in an experimental plant by distributors of three hygenical institutes, two technical high schools, and the German meteorological weather service. The results of the field investigations showed emitted germ quantities between 3.5 x 105 and 8,8 x 107 max. per second. This applies to volume flows between 5,000 to 10,000 m3/s, emitted in heights of 100 m above ground level. Therefore no proof of an increased load, above the ground, due to emissions could be furnished. This result was confirmed in dispersal calculations. The discharge of warmed up water into the receiving canal did not cause any remarkable changes in the germ quantities during summer- or winterly conditions. After calculating the portion of facultative pathogen micro-organisms on the totally emitted germ quantity, considering also the experimentally demonstrated higher die away rates of intestine germs in the plumes, the extend of danger to human health will be discussed. A remarkable danger of infections, due to germ discharge, directly or indirectly, has not been determined at cooling tower constructions, according to the latest technical experiences. (orig.)

377

Measurement and characterization of emissions from a gas liquor fed cooling tower  

Science.gov (United States)

Phase I cooling tower testing at the University of North Dakota Energy Research Center (UNDERC) was designed to use solvent extracted and steam stripped wastewater from fixed-bed gasification of lignite as makeup. The objective of this test was to simulate the proposed mode of operation at the Great Plains Gasification Associates (GPGA) plant. A crucial part of this study was the characterization of emissions from a stripped gas liquor (SGL) fed cooling tower. Several types of sampling equipment including a multicyclone, cooled impingers, and an XAD resin trap were used for the collection and retention of components in the tower evaporate. Results of this study indicated that a significant portion of the phenol and ammonia, and also some methanol, in the tower makeup stream were stripped into the atmosphere. Concentration levels of 26,900 ?g m -3 ammonia, 8000 ?g m -3 phenol and 2500 ? m -3 methanol were detected in the lower exhaust.

Galegher, Sheila J.; Mann, Michael D.

378

Reinforced concrete column- supported by hyperboloid cooling tower stability assessment for seismic loads  

International Nuclear Information System (INIS)

In recent years, the use of larger reinforced concrete column-supported hyperboloid cooling towers has been increased significantly. Thus, the investigation on failure criteria for structural components of such structures under different loads has been found as an essential need. Construction of cooling towers in seismic zones initiated the study on the dynamic behavior of such structures due to seismic loads. In this paper, finite element analyses have been performed to obtain the stress concentration, nonlinear behavior, stability or safety factor of the R. C. tower due to earthquakes loads. Outcomes of the study show that considerable plastic hinges were created in the X shape long columns of the R.C. hyperboloid cooling tower due to seismic loads, which resulted in a significant decrease in the stability safety factor and, an increase in concerns

379

Assessment of cooling tower (ultimate heat sink) performance in the Byron individual plant examination  

International Nuclear Information System (INIS)

A time-dependent model of the Byron Nuclear Generation Station safety-related cooling towers has been developed for use with the Byron PRA (IPE). The model can either be run in a stand-alone program with externally supplied heat loads, or can be directly coupled into MAAP (Modular Accident Analysis Program). The primary feature of the model is a careful tracking of the basin temperature through the progression of different severe accidents. Heat removal rates from containment, both from containment fan-coolers and the residual heat removal system, are determined by the feed-back of this time-varying return temperature. Also, the inventory of the basin is tracked in time, and this is controlled by make-up, evaporative losses due to the heat load supplied to the towers, and the possibility of unsecured blowdown. The model has been used to determine the overall capabilities and vulnerabilities of the Byron Ultimate Heat Sink (UHS). It was determined that the UHS is very reliable with respect to maintaining acceptably low basin temperatures, requiring only at most two of eight operating cooling tower fans. Further, when the two units have their Essential Service Water (ESW) systems cross-tied, one of four ESW operating pumps is sufficient to handle the loads from the accident unit with the other unit proceeding to an orderly shutdown. The major vulnerability of the Byron UHS is shown to be the ability to maintain inventory, although the time-scales for basin dry-out are relatively long, being eight to twenty-one hours, depending upon when blowdown is secured. (author)

380

A heat recovery system for air conditioning which allows disposal of wet cooling towers.  

Science.gov (United States)

The combined run-around coil heat recovery and cooling plant has been in full operation for about four months at the time of writing and appears to be performing as predicted. The predicted energy saving was 19,000 GJ/year and the actual is around 18,000 GJ/year. It provides a general limited cooling facility of 6 degrees K where previously cooling existed for operating theatres only. The capital cost of the total project was 390,000 pounds and disregarding fuel price fluctuations the heat recovery scheme should pay for itself in about seven years. In addition to the heat recovery and cooling provisions offered the scheme also enabled correction of a frost protection problem plus disposal of an existing wet cooling tower and hence should reduce the risk of Legionnaires Disease. Had these two projects been implemented separately the cost would have been 80,000 pounds but without heat recovery. The advantages of the scheme may be summarised as follows. Energy Cost Savings Frost Protection Elimination of Wet Cooling Tower Cooling Facility It is believed that a scheme as described in this paper would be of benefit to other existing hospitals and should be considered at the design stage of future new hospitals. At IRH it was possible to dispense completely with a wet cooling tower; for other schemes this may also be possible or at least the size and capacity of cooling towers could be reduced. PMID:10293020

McCullough, J

1988-04-01

 
 
 
 
381

Considerations required for the optimal design of a wet/dry cooling tower, under aspect of minimising visible vapour  

International Nuclear Information System (INIS)

Combined wet/dry cooling towers are to-day already available, using conventional materials for the wet and dry part. The investigations on the various arrangements on the air and water sides show the advantage of parallel arrangement on the air side and of the series arrangement on the water side. The size of the plant can be reduced by incorporating NTB elements. The use of closed systems with outside spray is also discussed, and prototype plants described. - It still remains to investigate the calculation of the visible vapour in respect of length, lifting height, density and transparency, as well as to determine the allowed physical values for the dimensioning of the combined wet/dry cooling towers. (orig.)

382

Water-cooled electronics  

CERN Document Server

LHC experiments demand on cooling of electronic instrumentation will be extremely high. A large number of racks will be located in underground caverns and counting rooms, where cooling by conventional climatisation would be prohibitively expensive. A series of tests on the direct water cooling of VMEbus units and of their standard power supplies is reported. A maximum dissipation of 60 W for each module and more than 1000 W delivered by the power supply to the crate have been reached. These values comply with the VMEbus specifications. (3 refs).

Dumont, G; Righini, B

2000-01-01

383

Dynamics of Legionella spp. and Bacterial Populations during the Proliferation of L. pneumophila in a Cooling Tower Facility?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The dynamics of Legionella spp. and of dominant bacteria were investigated in water from a cooling tower plant over a 9-month period which included several weeks when Legionella pneumophila proliferated. The structural diversity of both the bacteria and the Legionella spp. was monitored by a fingerprint technique, single-strand conformation polymorphism, and Legionella spp. and L. pneumophila were quantified by real-time quantitative PCR. The structure of the bacterial community did not chang...

We?ry, Nathalie; Bru-adan, Vale?rie; Minervini, Ce?line; Delge?nes, Jean-philippe; Garrelly, Laurent; Godon, Jean-jacques

2008-01-01

384

Nonlinear analysis of safety, damage and lifespan of wind-loaded natural draft cooling towers  

International Nuclear Information System (INIS)

While being important and optically impressive components of thermal power plants, natural draught cooling towers are in effect comparatively thin shell structures that must withstand hurricane force winds. As past experience has proven, current German design and analysis concepts implicitly lead to safe structures, but due to their linear-elastic background they cannot supply answers to questions dealing with realistic collapse loads, failure mechanisms and estimations of life expectancies. In this paper, appropriate computer-based nonlinear analysis concepts are presented which deal with those aspects. After a short exposition of the theoretical background for modeling tower shells as multi-layered shell continua by mixed finite elements under consideration of shear deformations, the approach is demonstrated through numerical simulation of collapse loads and failure modes of the Gundremmingen cooling towers. Based on the methodology presented, appraisals of reduced life times for hurricane-damaged towers, as well as different repair and retrofitting strategies can be carried out. (orig.)

385

Updating of a finite element model of the Cruas 2 cooling tower  

International Nuclear Information System (INIS)

A method based on modal analysis and inversion of a dynamic FEM model is used to detect changes in the dynamic behavior of nuclear plant cooling towers. Prior to detection, it is necessary to build a representative model of the structure. In this paper are given details about the CRUAS N. 2 cooling tower modelling and the updating procedure used to match the model to on-site measurements. First, were reviewed previous numerical and experimental studies on cooling towers vibrations. We found that the first eigenfrequencies of cooling towers are very sensitive to boundary conditions at the top and the bottom of the structure. Then, we built a beam and plate FEM model of the CRUAS N. 2 cooling tower. The first calculated modes were located in the proper frequency band (0.9 Hz - 1.30 Hz) but not distributed according to the experimental order. We decided to update the numerical model with MADMACS, an updating model software. It was necessary to: - decrease the shell stiffness by 30%; - increase the top ring stiffness by 300%; - modify the boundary conditions at the bottom by taking into account the soil impedance. In order to obtain a difference between the measured and the corresponding calculated frequencies less than 1%. The model was then judged to be realistic enough. (author). 23 figs., 13 refs., 1 annex

386

Concept of CFD model of natural draft wet-cooling tower flow  

Directory of Open Access Journals (Sweden)

Full Text Available The article deals with the development of CFD model of natural draft wet-cooling tower flow. The physical phenomena taking place within a natural draft wet cooling tower are described by the system of conservation law equations along with additional equations. The heat and mass transfer in the counterflow wet-cooling tower fill are described by model [1] which is based on the system of ordinary differential equations. Utilization of model [1] of the fill allows us to apply commonly measured fill characteristics as shown by [2].The boundary value problem resulting from the fill model is solved separately. The system of conservation law equations is interlinked with the system of ordinary differential equations describing the phenomena occurring in the counterflow wet-cooling tower fill via heat and mass sources and via boundary conditions. The concept of numerical solution is presented for the quasi one dimensional model of natural draft wet-cooling tower flow. The simulation results are shown.

Hyhlík T.

2014-03-01

387

Thermal performance of cross flow cooling towers in variable wet bulb temperature  

International Nuclear Information System (INIS)

Cooling towers are widely used in most industrial units to reject waste heat to the atmosphere. Wet towers are usually designed to operate in hot and dry weather conditions with narrow range of wet bulb temperature, but many cooling towers are required to operate in weather condition with large variation of wet bulb temperature which strongly affects the thermal performance of the towers. In this paper a conventional mathematical model is used to predict the thermal behavior of an existing cross flow tower under variable wet bulb temperature and the results are compared with experimental data in various operating conditions. Available fill characteristic curve of the tower is obtained to estimate its departure from the design conditions. It is found that when the wet bulb temperature increases, the approach, range and evaporation loss would increase considerably. Variation of evaporation loss versus wet bulb temperature was estimated. Finally the effect of placing an impact separator in front of air louvers on thermal performance of the tower is investigated.

388

Sea water for cooling Koeberg  

International Nuclear Information System (INIS)

The Koeberg-1 reactor under construction will house three separate water cooling systems. The third of these is the sea water cooling system, which draws sea water through the condensers to cool the low pressure steam exhausted by the turbine. The designs of the inlet basin, which provides sea water for the tertiary water cooling system, and the outfall point of the used water back into the sea are described

389

Comparison of wet and dry heat transfer and pressure drop tests of smooth and rough corrugated PVC packing in cooling towers  

International Nuclear Information System (INIS)

This paper presents the results of an experimental investigation of the performance of a cooling tower with PVC packing. The following were examined; the effect of surface roughness, the effect of the angle of roughness and the effect of packing spacing. The investigation was divided into two parts: comparison of film heat transfer with air pressure drop, without water circulation and comparison of enthalpy change and pressure drop in the model cooling tower, with circulation of water. Seven commercial packing were investigated, covering a size range of 1.1< P/D<1.70 and 1?p/e?5 and a discussion of the dimensionless correlation resulting is given

390

Performance analysis of heat transfer processes from wet and dry surfaces : cooling towers and heat exchangers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this work is to study the thermal and hydraulic performance of evaporatively cooled heat exchangers, including closed wet cooling towers, and dry tube heat exchangers with various geometries. Applications utilising such equipment exist in almost every thermal process. The investigation includes theoretical analysis, computational approaches, and experimental measurements. In this work, a computational model is presented for the thermal performance of closed wet cooling to...

Hasan, Ala Ali

2005-01-01

391

N3S-AERO: a multidimensional model for numerical simulation of all wet cooling tower systems  

International Nuclear Information System (INIS)

3D model is more required to optimize the design of new cooling tower by way of parameters studies, to improve the performance of the existing ones from changes in fill zone or water distribution. Therefore, the Directions des Etudes et Recherches with collaboration of the Direction de l'Equipement of EDF, has developed a specific version of the finite element CFD code N3S, denoted N3S-AERO, for the simulation of natural or mechanical draught wet cooling towers. It solves mass, momentum, heat and humidity averaged Navier-Stokes equations including buoyancy terms with variable density for air flow in the whole domain mass, heat equations for water flow in exchange zones. With standard results of N3S as air velocity and scalar fields, N3S-AERO gives in return water temperature fields mean values of variables at inlet or outlet of each exchange zone and thermal performance of the tower. 2D axisymmetrical and 3D industrial cases have soon been done. Major flow phenomena are well predicted and averaged cold water values are in good agreement with ID-TEFERI code or measurements

392

Construction of high power cooling tower. Examples of Dampierre-en-Burly and Chinon power plants  

International Nuclear Information System (INIS)

The increase sin the power of nuclear power stations situated near rivers with low flow rates when at their lowest levels means that recourse to closed circuit cooling is necessary. The construction of cooling towers is described in this article. The problems raised by the construction of such towers are examined as are the solutions found with respect to some examples. The Dampierre power station includes four cooling towers 165 metres high and 130 metres in diameter at the foot. Those of Chinon, located in a tourist area, are of the forced draught type in order to bring their height down to 30 metres, but they have the drawback of using up a significant amount of energy to actuate the fans

393

Effect of Fluid Maldistribution on the Performance of a Cross Flow Dry Cooling Tower  

International Nuclear Information System (INIS)

In all heat transfer and pressure drop analysis, it is assumed that the fluid is uniformly distributed. A serious reduction in dry cooling tower performance may result when the flow distribution is nonuniform. In this study, nonuniform flow distribution will be considered on both sided of the cooling tower, the reduction in heat transfer rates and consequently the increase of the energy losses will be derived for several flow arrangements. An analysis is presented to quantitatively evaluate the increase in pressure drop, energy losses and the degradation in heat transfer due to malflow distribution. the effect of maldistribution fluid on the rates of heat transfer of a dry cooling tower is experimentally determined. Experimental values of the heat transfer due to maldistribution are compared with the calculated one. It is shown that good agreements have been obtained. 7 figs

394

Magnetohydrodynamic Simulations of the Interaction of Magnetic Tower Jets with Interstellar Clouds including Cooling  

Science.gov (United States)

We carried out magnetohydrodynamic (MHD) simulations to reveal the formation mechanism of molecular towers observed in the central region of our galaxy. These molecular clouds can be formed by the interaction of magnetic tower jet with the interstellar gas. When the jet collides with dense HI clouds, the HI gas is compressed by the bow shock ahead of the jet. Since the density enhancement triggers the cooling instability because it increases the cooling rate, the shocked gas cools down and forms cold, dense gas. We carried out MHD simulations including the cooling. The magnetized jet which triggers the formation of the molecular column appears in global magnetohydrodynamic simulations of accretion disks, in which the magnetic loops emerging from the disk are twisted by the differential rotation between the footpoints of magnetic loops anchored to the disk. Numerical results indicate that the magnetic loops expand, and form a magnetic tower. When the ambient density is small, the propagation speed of the tower can be as large as the rotation speed of the disk. When the ambient density is high, the collision of the jet and the HI cloud forms dense molecular tower.

Asahina, Y.; Ogawa, T.; Matsumoto, R.

2013-03-01

395

Simultaneous prediction of internal and external aerodynamic and thermal flow fields of a natural-draft cooling tower in a cross-wind  

International Nuclear Information System (INIS)

The quantitative simulation of cooling-tower performance is useful to designers, enabling them to make optimal choices regarding: the type, volume and shape of the packing (i.e. fill); and the shape and size of the tower. In order to simulate performance realistically, non-uniformities of distribution of water and air mass-flow rates across the tower radius must be taken into account. This necessitates at least 2D modeling; and in order to establish the influence of a cross-wind, boundary conditions must be far away from the tower inlet and outlet, and 3D modeling must be performed. This paper is concerned with large wet natural-draught cooling towers of the type used in many steam power stations for cooling large quantities of water by direct contact with the atmosphere. The aim of the present work has been to improve the procedures of calculation by using numerical integration of the heat and mass transfer equations, and to connect internal and external aerodynamics thus enabling wind influence to be studied. It permits predicting the performance of a proposed design of the tower over a range of operating conditions. PHOENICS, a general-purpose computer code for fluid-flow simulation, is used to provide numerical solutions to governing differential equations

396

System approach to calculated grounding of reliability of new designs for cooling towers with metal frame  

International Nuclear Information System (INIS)

Dealt with are the methods of the system approach to reliable grounding of new design features of cooling towers with the metal frame. The new design of prestressed ferroconcrete shells is presented. It provides considerable saving in specific amount of material per structure and labor input for manufacturing. The problems to be solved by the researchers, designers builders and operating staff are stated on the basis of the system approach. Successful solution of these problems will provide reliability of the structure. An example of the system approach to the design of a guy rope cooling tower is given

397

Measurements in natural-draft wet cooling towers at the nuclear power station Philippsburg 1  

International Nuclear Information System (INIS)

An extensive measuring programme was carried out on the cooling tower of the nuclear power plant Phillipsburg in spring 1980, to simultaneously record all necessary parameters, and to compile the results to complete data sets. The aim of the programme was as follows: - to improve the state of knowledge by means of an extensive interdisciplinary field study, - to verify expert opinions- and calculated predictions (models for operation characteristics, emissions and propagation), - to inform the public of efforts made for environmentally sound cooling tower operation. The work was performed in 8 partial projects by interdisciplinary working groups of scientists. (orig./GL)

398

A community outbreak of Legionnaires' disease associated with a cooling tower in Vic and Gurb, Catalonia (Spain) in 2005.  

Science.gov (United States)

We report the investigation of a community-acquired outbreak of Legionnaires' disease. An epidemiological, environmental, and meteorological investigation was undertaken. Fifty-five cases were reported in October and November 2005. The exposure occurred in a large area, with 12 cases (21.8%) located between 1,800 and 3,400 metres from the source. Water sample cultures showed that Legionella pneumophila serogroup 1 (Lp-1) was present in five cooling towers in two industrial locations in Gurb (plants A and B). Two Lp-1 strains were recovered from plants A and B, but only Lp-1 strains from plant A showed a pulsed-field gel electrophoresis (PFGE) profile identical to those obtained from three of the cases. Inspection of the cooling towers in plant A revealed inadequate maintenance. Weather conditions in October 2005, with mostly high temperatures and high humidity, together with the flat terrain could have been favouring factors. This study showed a community outbreak from a cooling tower as a common source in a large area. Climate and terrain could explain the dissemination of contaminated aerosols. PMID:18752009

Ferré, M R Sala; Arias, C; Oliva, J M; Pedrol, A; García, M; Pellicer, T; Roura, P; Domínguez, A

2009-02-01

399

Experimental measurement of cooling tower emissions using image processing of sensitive papers  

Science.gov (United States)

Cooling tower emissions are harmful for several reasons such as air polluting, wetting, icing and solid particle deposition, but mainly due to human health hazards (i.e. Legionella). There are several methods for measuring drift drops. This paper is focussed on the sensitive paper technique, which is suitable in low drift scenarios and real conditions. The lack of an automatic classification method motivated the development of a digital image process algorithm for the Sensitive Paper method. This paper presents a detailed description of this method, in which, drop-like elements are identified by means of the Canny edge detector combined with some morphological operations. Afterwards, the application of a J48 decision tree is proposed as one of the most relevant contributions. This classification method allows us to discern between stains whose origin is a drop and stains whose origin is not a drop. The method is applied to a real case and results are presented in terms of drift and PM10 emissions. This involves the calculation of the main features of the droplet distribution at the cooling tower exit surface in terms of drop size distribution data, cumulative mass distribution curve and characteristic drop diameters. The Log-normal and the Rosin-Rammler distribution functions have been fitted to the experimental data collected in the tests and it can been concluded that the first one is the most suitable for experimental data among the functions tested (whereas the second one is less suitable). Realistic PM10 calculations include the measurement of drift emissions and Total Dissolved Solids as well as the size and number of drops. Results are compared to the method proposed by the U.S. Environmental Protection Agency assessing its overestimation. Drift emissions have found to be 0.0517% of the recirculating water, which is over the Spanish standards limit (0.05%).

Ruiz, J.; Kaiser, A. S.; Ballesta, M.; Gil, A.; Lucas, M.

2013-04-01

400

Experimental evaluation of aerodynamic inlet losses in natural draft dry cooling towers  

International Nuclear Information System (INIS)

The aerodynamic inlet losses at the base of circular natural draft dry cooling towers with horizontal radial and vertical circumferential heat exchanger arrangements, are investigated experimentally. Since the rectangular heat exchanger bundles in the horizontal radial arrangement cannot effectively cover the entire cross-sectional area and do not stretch continuously along the entire circumference of the tower, the inlet loss is found to be dependent on the particular layout. The actual flow pattern before the heat exchangers is found to be complex and unstable under certain geometric conditions. The losses are furthermore found to be dependent on the tower geometry and the heat exchanger flow resistance in the horizontal layout. In the vertical arrangement, the loss is found to be essentially independent of the heat exchanger resistance. By rounding off the inlet to the tower, reductions in inlet flow losses can be achieved under certain conditions

 
 
 
 
401

Cooling water injection device  

International Nuclear Information System (INIS)

The device of the present invention indicates a selection for injection of water to a reactor pressure vessel or a reactor container upon occurrence of such an emergency that ECCS should not be operated. Namely, a temperature detection means detects a temperature of high temperature incondensible gases generated upon flowing out of a molten reactor core due to failure of the reactor pressure vessel and reacting with concretes in the reactor container. A pressure detecting means detects a pressure in the reactor container. When the temperature detecting means detects a temperature higher than a saturation temperature at the detected pressure, an indication device judges the rupture of the pressure vessel, and indicates the reactor container as the destination for the injection of cooling water to cool the molten reactor core. On the other hand, when the pressure vessel is not ruptured, the temperature does not exceed the saturation temperature. Accordingly, the indication device indicates the reactor pressure vessel as the destination for the injection of cooling water. (I.S.)

402

A procedure for constructing the normative characteristics of chimney-type evaporative cooling towers from the results of field measurements  

Science.gov (United States)

A procedure for constructing the normative characteristics of chimney-type evaporative cooling towers equipped with different designs of heat-and-mass transfer (spraying) devices is developed using the results of balance tests carried out for many years on 34 cooling towers of different designs with areas ranging from 500 to 10000 m2.

Kalatuzov, V. A.

2007-11-01

403

Thermoelectrically cooled water trap  

Science.gov (United States)

A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

Micheels, Ronald H. (Concord, MA)

2006-02-21

404

Wind dependence on the flow rate in a natural draught cooling tower  

International Nuclear Information System (INIS)

The efficiency of a natural draught cooling tower depends, among other things, on the effect of the wind on the flow in the tower stack. Determinations were made on a natural draught wet cooling tower 100 metres high, for the purpose of studying this effects. As characteristic quantity, a typical height was determined, the values of which were worked out from the results of the measurements. The efficiency of the stack is affected the most in the case of average wind velocities (when the velocity of the wind is about equal to the mean velocity of the plume). This effect diminishes when the velocity of the wind increases. In the case of average wind velocities, the direction of the wind has an effect, owing to the neighbouring buildings; for slightly greater wind velocities, no effect could be found

405

The Water Quality Control of the Secondary Cooling Water under a Normal Operation of 30 MWth in HANARO  

Energy Technology Data Exchange (ETDEWEB)

HANARO, a multi-purpose research reactor, a 30 MWth open-tank-in-pool type, has been under a full power operation since 2005. The heat generated by the core of HANARO is transferred to the primary cooling water. And the cooling water transfers the heat to the secondary cooling water through the primary cooling heat exchanger. The heat absorbed by the secondary cooling water is removed through a cooling tower. The quality of the secondary cooling water is deteriorated by a temperature variation of the cooling water and a foreign material flowing over the cooling water through the cooling tower fan for a cooling. From these, a corrosion reduces the life time of a system, a scale degrades the heat transfer effect and a sludge and slime induces a local corrosion. For reducing these impacts, the quality of the secondary cooling water is treated by a high ca-hardness water quality program by maintaining a super saturated condition of ions, 12 of a ca-hardness concentration. After an overhaul maintenance of a secondary cooling tower composed of a secondary cooling system in 2007, a secondary cooling water stored in the cooling tower basin was replaced with a fresh city water. In this year, a water quality deterioration test has been performed under a full power operation and a mode of a twenty three day operation and twelve day maintenance for setting a beginning control limit of the secondary cooling water. This paper describes the water quality deterioration test for the secondary cooling system under a full power operation of 30 MWth including a test method, a test requirement and a test result.

Park, Young Chul; Lee, Young Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lim, Rag Yong [Hansoo Tech. Co. Ltd., Daejeon (Korea, Republic of)

2008-10-15

406

In Situ g-PHA Measurements of the 285-3H Cooling Tower Components  

Energy Technology Data Exchange (ETDEWEB)

The Analytical Development Section of Savannah River Technology Center was requested by the Facility Disposition Division to conduct in-situ gamma-ray pulse height analysis measurements to provide input toward the decision to unconditionally release the 285-3H cooling tower.

Salaymeh, S.R.

2001-05-23

407

TESTING AND ANALYSIS OF A WET-DRY CROSSFLOW COOLING TOWER, VOLUME II: APPENDICES  

Science.gov (United States)

The report discusses the test program and performance analysis of a single-cell mechanical-draft wet/dry cooling tower in Cliffside, NC. Objectives of the program were to obtain performance data and results on mass transfer, heat transfer, fluid flow, plume formation, and acousti...

408

Cooling tower drift study at the Oak Ridge Gaseous Diffusion Plant  

International Nuclear Information System (INIS)

The environmental study of cooling towers at the ORGDP was continued in 1978. The first investigation conducted in 1973 provided valuable first hand information on drift from two cooling tower cells at ORGDP; however, the drift percentage of 0.1% measured in that test appeared to be high. The 1978 drift study was planned and performed to more closely define the drift phenomenon of the cooling tower complex. The cooling tower cells were involved in the test with drift and ground deposition measurements being performed simultaneously. The average drift percentage measured in this test was 0.03% with acceptable agreement among the ten cells tested. The downfield deposition measurements of chromium supported the deposition findings of the 1973 study. The results of the 1978 studies are considered more reliable than those obtained in 1973 because of the greater mass of data obtained from a greater number of tested cells. The results also indicated that the sensitive paper method with its large sampling volume provides more reliable source characteristics information than the optical measuring device with a very small sampling volume

409

Transition to a new generation of large natural-draught cooling towers  

International Nuclear Information System (INIS)

A concept of a new generation of natural-draught cooling towers for large nuclear power plant units is presented considering optimization and calculation methods, safety philosophy, dimension criteria, constructional measures, building materials, construction surveying, climbing formwork, and climbing cranes. The first installation will be available by 1990, with a unit 250 m in diameter by 150 m high

410

40 CFR Table 4 to Subpart F of... - Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104  

Science.gov (United States)

... false Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104 4 Table...Part 63—Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104 Chemical...

2010-07-01

411

Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant. [Transport of drift-derived chromium in terrestrial ecosystems  

Energy Technology Data Exchange (ETDEWEB)

The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant.

Taylor, F.G.; Hanna, S.R.; Parr, P.D.

1979-01-01

412

Influence of building and supply conditions on coolant pumps and the various coolant pump designs for cooling towers  

International Nuclear Information System (INIS)

This contribution tries to present the various factors influencing the design of cooling tower pumps. As cooling tower pumps are very often designed as concrete speral casing pumps, the suction bend construction often offers itself. The running wheel of cooling tower pumps is usually of semi-axial design, whereby one has to differ between rigid, adjustable, and resetable running wheels. Finally, the type of cooling system and the nominal width are decisive for either the construction type of the spiral casing pump or the tubular type pump. Both methods are compared in a critical way. (orig.)

413

A model for radionuclide transport in the Cooling Water System  

International Nuclear Information System (INIS)

A radionuclide transport model developed to assess radiological levels in the K-reactor Cooling Water System (CWS) in the event of an inadvertent process water (PW) leakage to the cooling water (CW) in the heat exchangers (HX) is described. During and following a process water leak, the radionuclide transport model determines the time-dependent release rates of radionuclide from the cooling water system to the environment via evaporation to the atmosphere and blow-down to the Savannah River. The developed model allows for delay times associated with the transport of the cooling water radioactivity through cooling water system components. Additionally, this model simulates the time-dependent behavior of radionuclides levels in various CWS components. The developed model is incorporated into the K-reactor Cooling Tower Activity (KCTA) code. KCTA allows the accident (heat exchanger leak rate) and the cooling tower blow-down and evaporation rates to be described as time-dependent functions. Thus, the postulated leak and the consequence of the assumed leak can be modelled realistically. This model is the first of three models to be ultimately assembled to form a comprehensive Liquid Pathway Activity System (LPAS). LPAS will offer integrated formation, transport, deposition, and release estimates for radionuclides formed in a SRS facility. Process water and river water modules are forthcoming as input and downstream components, respectively, for KCTA

414

Use of Air2Air Technology to Recover Fresh-Water from the Normal Evaporative Cooling Loss at Coal-Based Thermoelectric Power Plants  

Energy Technology Data Exchange (ETDEWEB)

This program was undertaken to build and operate the first Air2Air{trademark} Water Conservation Cooling Tower at a power plant, giving a validated basis and capability for water conservation by this method. Air2Air{trademark} water conservation technology recovers a portion of the traditional cooling tower evaporate. The Condensing Module provides an air-to-air heat exchanger above the wet fill media, extracting the heat from the hot saturated moist air leaving in the cooling tower and condensing water. The rate of evaporate water recovery is typically 10%-25% annually, depending on the cooling tower location (climate).

Ken Mortensen

2009-06-30

415

Wind tunnel experiments on cooling tower plumes. Pt. 2  

International Nuclear Information System (INIS)

The basic characteristics of plumes issuing into a boundary layer type of cross flow are reported. The flow can be considered as an interaction between two vorticity fields with different length scales and turbulence intensities. The large eddies of the oncoming boundary layer are responsible for the observed sudden changes in the plume direction. The type of structures emanating the tower depends on the instantaneous velocity ratio. Mean velocities and normal velocity gradients are smaller than in the case of uniform cross-flow (Andreopoulos, 1986) and therefore the measured turbulence intensities were lower too. The cross-stream turbulence brings high momentum fluid into the wake region and the velocity defect decays very rapidly. Dilution of the plumes takes place faster in the presence of external turbulence than in the case with uniform cross-flow. The spreading rate is increased dramatically by the external turbulence which causes different effects on the hydrodynamic and thermal fields. (orig.)

416

Mathematical model of drift deposition from a bifurcated cooling tower plume  

International Nuclear Information System (INIS)

Cooling tower drift deposition modeling has been extended by including centrifugal force induced through plume bifurcation in a crosswind as a mechanism for drift droplet removal from the plume. The model, in its current state of development, is capable of predicting the trajectory of a single droplet from the stage of strong interaction with the vortex field soon after droplet emission at the tower top through the stage of droplet evaporation in an unsaturated atmosphere after droplet breakaway from the plume. The computer program developed from the mathematical formulation has been used to explore the dependency of the droplet trajectory on droplet size, vortex strength, point of droplet emission, drag coefficient, droplet efflux speed, and ambient conditions. A specific application to drift from a mechanical-draft cooling tower (for a wind speed twice the efflux speed, a relative humidity of 70 per cent, and an initial droplet radius of 100 ?m) showed the droplet to follow a helical trajectory within the plume, with breakaway occurring at 2.5 tower diameters downwind and ground impact of the droplet (reduced through evaporation to 55 ?m radius) at 11 tower diameters

417

Playing it cool  

International Nuclear Information System (INIS)

This article highlights the attempts of the electric utilities to improve the public perception of cooling towers. Details are given of the efforts of different companies in promoting ozone technology for the treatment of cooling tower water, the use of low noise fans, air and thermal pollution control, the use of products for cooling towers to reduce the plumes, and the certification of cooling towers. (UK)

418

Spreading of cracks in R. C. hyperbolic cooling towers with and without imperfection due to weight, thermal and wind loads  

International Nuclear Information System (INIS)

Imprecise construction work might cause imperfection in the shell of R.C.hyperbolic cooling towers. The cooling towers with large imperfection could collapse due to wind load. The aim of this research is to study the cracks spreading in the shell of a typical R.C. cooling tower with and without imperfection. In Finite Element analysis reinforce bars with nonlinear behavior and solid elements were used. The solid elements which were used in this analysis could crack in three directions. The study on the sample cooling towers showed that deformations and crack spreading differ in the cooling tower shell with and without imperfection due to weight and thermal loads. At he end of the weight and thermal loads, vertical cracks were seen all over the outer side of the perfect shell and intermittent horizontal cracks happened in the shell of cooling tower where it had : its minimum thickness. On the other hand, in an imperfect shell, intermittent vertical and horizontal cracks were seen on the outside of the cooling tower shell due to the weight and thermal loads. When wind loads was added to the weight and thermal loads, the cracks spreading was seen to be similar for both perfect and imperfect R.C. Shell