Science.gov

Sample records for cooling tower performance

  1. Investigation of Natural Draft Cooling Tower Performance Using Neural Network

    NASA Astrophysics Data System (ADS)

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

    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, Δp, ɛ) 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.

  2. Effect of solar radiation on the performance of cross flow wet cooling tower in hot climate of Iran

    NASA Astrophysics Data System (ADS)

    Banooni, Salem; Chitsazan, Ali

    2016-11-01

    In some cities such as Ahvaz-Iran, the solar radiation is very high and the annual-mean-daily of the global solar radiation is about 17.33 MJ m2 d-1. Solar radiation as an external heat source seems to affect the thermal performance of the cooling towers. Usually, in modeling cooling tower, the effects of solar radiation are ignored. To investigate the effect of sunshade on the performance and modeling of the cooling tower, the experiments were conducted in two different states, cooling towers with and without sunshade. In this study, the Merkel's approach and finite difference technique are used to predict the thermal behavior of cross flow wet cooling tower without sunshade and the results are compared with the data obtained from the cooling towers with and without sunshade. Results showed that the sunshade is very efficient and it reduced the outlet water temperature, the approach and the water exergy of the cooling tower up to 1.2 °C, 15 and 1.1 %, respectively and increased the range and the efficiency of the cooling tower up to 29 and 37 %, respectively. Also, the sunshade decreased the error between the experimental data of the cooling tower with sunshade and the modeling results of the cooling tower without sunshade 1.85 % in average.

  3. Effect of solar radiation on the performance of cross flow wet cooling tower in hot climate of Iran

    NASA Astrophysics Data System (ADS)

    Banooni, Salem; Chitsazan, Ali

    2016-01-01

    In some cities such as Ahvaz-Iran, the solar radiation is very high and the annual-mean-daily of the global solar radiation is about 17.33 MJ m2 d-1. Solar radiation as an external heat source seems to affect the thermal performance of the cooling towers. Usually, in modeling cooling tower, the effects of solar radiation are ignored. To investigate the effect of sunshade on the performance and modeling of the cooling tower, the experiments were conducted in two different states, cooling towers with and without sunshade. In this study, the Merkel's approach and finite difference technique are used to predict the thermal behavior of cross flow wet cooling tower without sunshade and the results are compared with the data obtained from the cooling towers with and without sunshade. Results showed that the sunshade is very efficient and it reduced the outlet water temperature, the approach and the water exergy of the cooling tower up to 1.2 °C, 15 and 1.1 %, respectively and increased the range and the efficiency of the cooling tower up to 29 and 37 %, respectively. Also, the sunshade decreased the error between the experimental data of the cooling tower with sunshade and the modeling results of the cooling tower without sunshade 1.85 % in average.

  4. Utility avoids cooling tower

    SciTech Connect

    1994-08-01

    After more than four years of often rancorous debate, New Jersey late last month approved a plan that permits the state`s largest utility to reclaim and restore Delaware Bay marshland instead of constructing a costly cooling tower for two nuclear power units. Environmental interests say they`ll appeal the wetlands proposal, calling it an {open_quotes}unproven experiment{close_quotes} that violates Clean Water Act provisions.

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

    NASA Astrophysics Data System (ADS)

    Banooni, Salem; Chitsazan, Ali

    2014-05-01

    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.

  6. PBF Cooling Tower. Hot deck of Cooling Tower with fan ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower. Hot deck of Cooling Tower with fan motors in place. Fan's propeller blades (not in view) rotate within lower portion of vents. Inlet pipe is a left of view. Contractor's construction buildings in view to right. Photographer: Larry Page. Date: June 30, 1969. INEEL negative no. 69-3781 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  7. Ozonation of cooling tower waters

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

  8. Investigation of the effect of packing location on performance of closed wet cooling tower based on exergy analysis

    NASA Astrophysics Data System (ADS)

    Qasim, S. M.; Hayder, M. J.

    2016-08-01

    In this paper, the effect of packing location on thermal performance of Closed Wet Cooling Tower (CWCT) based on exergy analysis has been studied. The experimental study incorporates design, manufacture and testing of a modified counter flow forced draft CWCT prototype. The modification based on addition packing to the conventional CWCT. The variation of spray water temperature, air dry bulb temperature, air wet bulb temperature, enthalpy and relative humidity of air for different position along the tower are measured experimentally. Applying the exergy destruction method for the cooling tower; exergy destruction, exergy efficiency, exergy of water and air were calculated for two cases: CWCT with packing below the heat exchanger and CWCT with packing above the heat exchanger. It is highly important to analyze the exergy along the cooling tower height. Therefore, the exergy analysis of different elements along the height of the tower is carried out. Results show that the total exergy destruction of modified CWCT is higher when the heat exchanger is located above the packing at the highest point of the tower.

  9. Ozone Treatment For Cooling Towers

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  10. Plant Vogtle cooling tower studies

    SciTech Connect

    O'Steen, L.

    2000-01-26

    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.

  11. 2004 Savannah River Cooling Tower Collection (U)

    SciTech Connect

    Garrett, Alfred; Parker, Matthew J.; Villa-Aleman, E.

    2005-05-01

    The Savannah River National Laboratory (SRNL) collected ground truth in and around the Savannah River Site (SRS) F-Area cooling tower during the spring and summer of 2004. The ground truth data consisted of air temperatures and humidity inside and around the cooling tower, wind speed and direction, cooling water temperatures entering; inside adn leaving the cooling tower, cooling tower fan exhaust velocities and thermal images taken from helicopters. The F-Area cooling tower had six cells, some of which were operated with fans off during long periods of the collection. The operating status (fan on or off) for each of the six cells was derived from operations logbooks and added to the collection database. SRNL collected the F-Area cooling tower data to produce a database suitable for validation of a cooling tower model used by one of SRNL's customer agencies. SRNL considers the data to be accurate enough for use in a model validation effort. Also, the thermal images of the cooling tower decks and throats combined with the temperature measurements inside the tower provide valuable information about the appearance of cooling towers as a function of fan operating status and time of day.

  12. Ozone inhibits corrosion in cooling towers

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    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.

  13. Vortex-augmented cooling tower - windmill combination

    DOEpatents

    McAllister, J.E. Jr.

    1982-09-02

    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 passage to provide power as a by-product.

  14. Using ozone to treat cooling tower water

    SciTech Connect

    Webster, L.

    1995-07-01

    Ozone is a controversial but promising alternative to chemicals for treating water in cooling towers. A powerful disinfectant, ozone can prevent biofouling of heat exchange surfaces, and may mitigate scale and corrosion. Ozone treatment of cooling towers can cut costs for energy, water, sewage, and regulatory compliance. Ozone treatment is an electrotechnology, but ozone equipment represents only a small electric load. Although ozone has provided excellent results in some cooling tower applications, its effectiveness has not been proven conclusively. Less than 1,000 cooling towers use ozone water treatment in the United States. Acceptance of this technology is increasing, however, as indicated by its use by such large firms as IBM, AT and T, DuPont, and Xerox, and by its adoption by some chemical water treatment suppliers. The energy efficiency implications of ozone treatment are being researched. Southern California Edison found that in some systems, ozone treatment improved chiller efficiency up to 20 percent due to cleaner heat exchange surfaces.

  15. An economical solution to cooling tower drift

    SciTech Connect

    Pedersen, G.C.; Lamkin, V.K.; Seich, M.

    1987-01-01

    Most processes one encounters in the refining and petrochemical industries require the rejection of waste heat. The most economical and effective means of accomplishing this is through the use of cooling towers. Heat is transferred by convection and evaporation (mass transfer) by the direct contact of the atmospheric air and water. This results in a major environmental concern of cooling towers - DRIFT, which is discussed in this paper.

  16. Stripping of phenols in model cooling towers

    SciTech Connect

    Turner, C.D.; Moe, T.A.; Wentz, C.A.

    1987-01-01

    Cooling towers are used to remove waste heat from unit operations in chemical processing plants. Using cooling towers for wastewater treatment and disposal through internal recycling has become an important alternative because of stricter wastewater discharge standards, the expense of specialized wastewater treatment systems and the limited availability and cost of water in arid regions. Designs for synfuels plants must address the problem of wastewater disposal. Alternative systems under consideration usually include zero discharge designs that incorporate evaporative cooling towers in the system. The mechanisms for contaminant removal in cooling towers are biological oxidation, stripping and chemical precipitation. Chemical precipitation is generally considered undesirable because of losses in heat transfer efficiency. Predicting whether stripping or biological oxidation will be the primary removal mechanism for phenolic compounds from coal conversion wastewaters used as makeup in cooling towers does not appear to be possible based on the results of these tests. The tests do indicate that the biological oxidation of phenol is possible in forced draft cooling towers.

  17. Mycobacteria in Finnish cooling tower waters.

    PubMed

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

    2014-04-01

    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

  18. Simple model of a cooling tower plume

    NASA Astrophysics Data System (ADS)

    Jan, Cizek; Jiri, Nozicka

    2016-06-01

    This article discusses the possibilities in the area of modeling of the so called cooling tower plume emergent at operating evaporating cooling systems. As opposed to recent publication, this text focuses on the possibilities of a simplified analytic description of the whole problem where this description shall - in the future - form the base of a calculation algorithms enabling to simulate the efficiency of systems reducing this cooling tower plume. The procedure is based on the application of basic formula for the calculation of the velocity and concentration fields in the area above the cooling tower. These calculation is then used to determine the form and the total volume of the plume. Although this approach does not offer more exact results, it can provide a basic understanding of the impact of individual quantities relating to this problem.

  19. NASA Marshall Space Flight Center Improves Cooling System Performance: Best Management Practice Case Study #10: Cooling Towers (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) has a longstanding sustainability program that revolves around energy and water efficiency as well as environmental protection. MSFC identified a problematic cooling loop with six separate compressor heat exchangers and a history of poor efficiency. The facility engineering team at MSFC partnered with Flozone Services, Incorporated to implement a comprehensive water treatment platform to improve the overall efficiency of the system.

  20. Wet/dry cooling tower and method

    DOEpatents

    Glicksman, Leon R.; Rohsenow, Warren R.

    1981-01-01

    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.

  1. Counter-Flow Cooling Tower Test Cell

    NASA Astrophysics Data System (ADS)

    Dvořák, Lukáš; Nožička, Jiří

    2014-03-01

    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.

  2. Estimating total aqueous and airborne chemical emissions from ozonated and chemically treated cooling towers

    SciTech Connect

    Pryor, A.

    1996-10-01

    Cooling tower operations result in aqueous and airborne emissions into the environment in the form of blowdown and drift, respectively. Increased regulatory and licensing requirements often obligate end users to quantify the nature and amount of any added chemicals in such emissions. This paper presents a methodology whereby cooling tower operators can perform such calculations for conventionally chemically treated cooling towers as well as ozonated cooling towers. Emissions from cooling towers depend on the operating characteristics of the tower (recirculation rate, drift rate), makeup and cooling water quality (makeup water mineral concentration, cooling water cycles of concentration), the amount of chemicals added to the cooling water, and/or the amount of ozone injected into the cooling water and the mass transfer efficiency of the ozone injection process.

  3. Cooling tower water conditioning study. [using ozone

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

  4. 50. NORTHERN VIEW OF NONEVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. NORTHERN VIEW OF NON-EVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS IN CENTER, AND EVAPORATIVE WASTE WATER COOLING TOWERS ON RIGHT. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

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

    PubMed Central

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

    2009-01-01

    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

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

    PubMed

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

    2009-01-01

    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

  7. Legionella spp. in Puerto Rico cooling towers

    SciTech Connect

    Negron-Alvira, A.; Perez-Suarez, I.; Hazen, T.C. )

    1988-10-01

    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. gormanii were observed in at least one of the cooling towers. L. pneumophila was the most abundant species; its density reached 10{sup 5} cells per ml, which is within the range that is considered potentially pathogenic to humans. A significantly higher density of L. pneumophila was observed in the cooling tower water that was not being treated with biocides. Percent respiration (INT) and total cell activity (acridine orange direct count) were inversely correlated with bacterial density. This study demonstrates that Legionella spp. are present in tropical air-conditioning cooling systems and that, without continuous biocide treatment, they may reach densities that present a health risk.

  8. Legionella in Puerto Rico cooling towers

    SciTech Connect

    Negron-Alviro, A.; Perez-Suarez, I.; Hazen, T.C.

    1988-12-31

    Water samples from air conditioning cooling towers receiving different treatment protocols on five large municipal buildings in San Juan, Puerto Rico were assayed for various species and serogroups of Legionella spp. using direct immunofluorescence. Several water quality parameters were also measured with each sample. Guinea pigs were inoculated with water samples to confirm pathogenicity and recover viable organisms. Legionella pneumophila (1-6), L. bozemanii, L. micdadei, L. dumoffii, and L. gormanii were observed in at least one of the cooling towers. L. pneumophila was the most abundant species, reaching 10{sup 5} cells/ml, within the range that is considered potentially pathogenic to humans. A significantly higher density of L. pneumophila was observed in the cooling tower water that was not being treated with biocides. Percent respiration (INT) and total cell activity (AODC), were inversely correlated with bacterial density. This study demonstrates that Legionella spp. are present in tropical air-conditioning cooling systems, and without continuous biocide treatment may reach densities that present a health risk.

  9. Legionella spp. in Puerto Rico cooling towers.

    PubMed Central

    Negrón-Alvíra, A; Pérez-Suarez, I; Hazen, T C

    1988-01-01

    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. gormanii were observed in at least one of the cooling towers. L. pneumophila was the most abundant species; its density reached 10(5) cells per ml, which is within the range that is considered potentially pathogenic to humans. A significantly higher density of L. pneumophila was observed in the cooling tower water that was not being treated with biocides. Percent respiration (INT) and total cell activity (acridine orange direct count) were inversely correlated with bacterial density. This study demonstrates that Legionella spp. are present in tropical air-conditioning cooling systems and that, without continuous biocide treatment, they may reach densities that present a health risk. PMID:3202625

  10. Technical Evaluation of Side Stream Filtration for Cooling Towers

    SciTech Connect

    2012-10-01

    Cooling towers are an integral component of many refrigeration systems, providing comfort or process cooling across a broad range of applications. Cooling towers represent the point in a cooling system where heat is dissipated to the atmosphere through evaporation. Cooling towers are commonly used in industrial applications and in large commercial buildings to release waste heat extracted from a process or building system through evaporation of water.

  11. Side Stream Filtration for Cooling Towers

    SciTech Connect

    2012-10-20

    This technology evaluation assesses side stream filtration options for cooling towers, with an objective to assess key attributes that optimize energy and water savings along with providing information on specific technology and implementation options. This information can be used to assist Federal sites to determine which options may be most appropriate for their applications. This evaluation provides an overview of the characterization of side stream filtration technology, describes typical applications, and details specific types of filtration technology.

  12. Aspects of cooling tower biocides and protozoa

    SciTech Connect

    Berk, S.G.; Ashburn, R.J.; Ting, R.S.

    1998-12-31

    Previous work has shown that certain cooling tower amoebae and ciliated protozoa are resistant to several cooling tower biocides, even at the manufacturer`s recommended dosages. For the present study, an Acunthumoeba species was isolated from a cooling tower in Australia. Suspensions of the trophozoites (feeding stages) were exposed to isothiazolones. Cysts were tested separately. The minimum lethal concentration (MLC) for trophozoites was between 31-62 ppm of the biocide product, which is slightly less than the MLC for an amoebae species from the United States; and cyst forms were twofold more resistant than those of the US species, with a MLC of 62,500 ppm. A ciliate and an amoeba species were also exposed to bromochlorodimethylhydantoin. The MLC for the ciliate species was 1 ppm of the biocide product, and the MLC was 30--40 ppm for the amoeba trophozoites. Since amoebae can expel vesicles containing live Legionella, experiments were conducted to determine whether exposure of Acunthamoebu polyphugu to biocides influenced release of such potentially infectious particles. Vesicle release was not inhibited by any of the three biocides: quaternary ammonium compounds (QACs), isothiazolones, and a thiocarbamate compound. These results suggest that amoebae from various sources are resistant to recommended levels of biocides, and the amoebae may continue to release potentially infectious vesicles in the presence of biocides.

  13. Water-conserving cooling tower treatment

    SciTech Connect

    Mathie, A.J.

    1996-12-31

    Water conservation in cooling towers and evaporative coolers can finally become a reality. Also, fouled closed hot and chilled water systems can be restored to near original efficiency using the same technology. The barrier limiting the traditional water treatment industry from serious involvement in water conservation is the lack of a really good chemical to control scale. Poor scale inhibitors are the reason for a heavy bleed. Minerals concentrated by evaporation is wasted to the sewer while low solids make-up water fills the tower. Water conservation is important because of the increasing usable water shortage, the cost to add infrastructure to deliver increasing amounts of water to accommodate growth and the limitations imposed on disposal to the sewer. Now, due to innovations in chemical treatment, users of cooling towers and evaporative coolers can conserve water. In this presentation the author assumes the audience has some knowledge of traditional water treatment. Except for a few general references to establish common understanding, the author confines his remarks to discussing an advanced technology developed by DIAS, Inc., and the economics of its use.

  14. Analysis of Radiant Cooling System Configurations Integrated with Cooling Tower for Different Indian Climatic Zones

    SciTech Connect

    Mathur, Jyotirmay; Bhandari, Mahabir S; Jain, Robin; Srivastava, Prateek

    2016-01-01

    Radiant cooling system has proven to be a low energy consumption system for building cooling needs. This study describes the use of cooling tower in radiant cooling system to improve the overall system efficiency. A comprehensive simulation feasibility study of the application of cooling tower in radiant cooling system was performed for the fifteen cities in different climatic zones of India. It was found that in summer, the wet bulb temperature (WBT) of the different climatic zones except warm-humid is suitable for the integration of cooling tower with radiant cooling system. In these climates, cooling tower can provide on average 24 C to 27 C water In order to achieve the energy saving potential, three different configurations of radiant cooling system have been compared in terms of energy consumption. The different configurations of the radiant cooling system integrated with cooling tower are: (1) provide chilled water to the floor, wall and ceiling mounted tubular installation. (2) provide chilled water to the wall and ceiling mounted tabular installation. In this arrangement a separate chiller has also been used to provide chilled water at 16 C to the floor mounted tubular installation. (3) provide chilled water to the wall mounted tabular installation and a separate chiller is used to provide chilled water at 16 C to the floor and ceiling mounted tabular installation. A dedicated outdoor air system is also coupled for dehumidification and ventilation in all three configurations. A conventional all-air system was simulated as a baseline to compare these configurations for assessing the energy saving potential.

  15. Droplet size of cooling tower fog.

    PubMed

    Rothman, T; Ledbetter, J O

    1975-01-01

    Fog from cooling towers causes problems of visibility and icing along roadways adjacent to the towers; moreover, the visible plume from the towers offers difficulty in that it is equated by much of the public with air pollution. It is desirable to know the size of the fog droplets in order to plan abatement procedures and to determine the airborne lifetimes of such fogs. The methodology involved capturing the droplets on slides coated with a vaseline-mineral oil mixture, making photomicrographs of the droplets, counting and sizing the droplets into eight droplet diameter increments; namely less than 5 mum, 5-10 mum, 10-20 mum, 20-40 mum, 40-60 mum, 60-80 mum, 80-100 mum, and greater than 100 mum. The resulting distribution was similar to that for natural fogs and clouds; i.e., it was bi-modal, the first mode at less than 5 mum containing the vast majority of the droplets, and the second at 20-40 mum. This study agrees with others that the size distribution of a fog in a saturated environment is continuously changing, with the smaller droplets tending to evaporate and the larger ones tending to grow, thus shifting the second mode toward larger sizes.

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

    DOEpatents

    Bharathan, Desikan; Hassani, A. Vahab

    1997-01-01

    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.

  17. The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers

    SciTech Connect

    Abedi-Nik, Farhad; Sabouri-Ghomi, Saeid

    2008-07-08

    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.

  18. CFD MODELING ANALYSIS OF MECHANICAL DRAFT COOLING TOWER

    SciTech Connect

    Lee, S; Alfred Garrett, A; James02 Bollinger, J; Larry Koffman, L

    2008-03-03

    Industrial processes use mechanical draft cooling towers (MDCT's) to dissipate waste heat by transferring heat from water to air via evaporative cooling, which causes air humidification. The Savannah River Site (SRS) has a MDCT consisting of four independent compartments called cells. Each cell has its own fan to help maximize heat transfer between ambient air and circulated water. The primary objective of the work is to conduct a parametric study for cooling tower performance under different fan speeds and ambient air conditions. The Savannah River National Laboratory (SRNL) developed a computational fluid dynamics (CFD) model to achieve the objective. The model uses three-dimensional steady-state momentum, continuity equations, air-vapor species balance equation, and two-equation turbulence as the basic governing equations. It was assumed that vapor phase is always transported by the continuous air phase with no slip velocity. In this case, water droplet component was considered as discrete phase for the interfacial heat and mass transfer via Lagrangian approach. Thus, the air-vapor mixture model with discrete water droplet phase is used for the analysis. A series of the modeling calculations was performed to investigate the impact of ambient and operating conditions on the thermal performance of the cooling tower when fans were operating and when they were turned off. The model was benchmarked against the literature data and the SRS test results for key parameters such as air temperature and humidity at the tower exit and water temperature for given ambient conditions. Detailed results will be presented here.

  19. Vortex-augmented cooling tower-windmill combination

    DOEpatents

    McAllister, Jr., John E.

    1985-01-01

    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.

  20. 36. EASTERN VIEW OF BOTTOM CONE OF GAS COOLING TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. EASTERN VIEW OF BOTTOM CONE OF GAS COOLING TOWER No. 1 AND TWO GAS COOLING TOWER SERVICE WATER PUMPS IN THE GAS WASHER PUMP HOUSE. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  1. PBF Cooling Tower. View of stairway to fan deck. Vents ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower. View of stairway to fan deck. Vents are made of redwood. Camera facing southwest toward north side of Cooling Tower. Siding is corrugated asbestos concrete. Photographer: Kirsh. Date: June 6, 1969. INEEL negative no. 69-3463 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  2. Bacterial aerosols produced from a cooling tower using wastewater effluent

    SciTech Connect

    Adams, A.P.; Garbett, M.; Rees, H.B.; Lewis, B.G.

    1980-03-01

    A cooling tower, which receives make-up water from a municipal wastewater treatment plant, was studied. Wastewater effluent was super-chlorinated, then treated with lime and a commercial coagulant to remove phosphates, calcium, magnesium, and suspended solids before it was pumped into the cooling tower. The chlorination and coagulation described above were used to reduce deposition of scale and slime on the power plant condenser surfaces. Bacterial counts were made of the cooling tower basin waters and of the aerosols exiting the cooling tower vents. It was dicovered that 39% of bacteria exiting the cooling tower vents were of the genus Pseudomonas. A few pathogenic microbes were also found to be present in the aerosolized particles but their numbers were so low that they were considered insignificant.

  3. Use of nanofiltration to reduce cooling tower water usage.

    SciTech Connect

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

    2010-09-01

    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%.

  4. Use of nanofiltration to reduce cooling tower water consumption.

    SciTech Connect

    Altman, Susan Jeanne; Ciferno, Jared

    2010-10-01

    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%.

  5. Operational cooling tower model (CTTOOL V1.0)

    SciTech Connect

    Aleman, S.; LocalDomainServers, L.; Garrett, A.

    2015-01-01

    Mechanical draft cooling towers (MDCT’s) are widely used to remove waste heat from industrial processes, including suspected proliferators of weapons of mass destruction (WMD). The temperature of the air being exhausted from the MDCT is proportional to the amount of thermal energy being removed from the process cooling water, although ambient weather conditions and cooling water flow rate must be known or estimated to calculate the rate of thermal energy dissipation (Q). It is theoretically possible to derive MDCT air exhaust temperatures from thermal images taken from a remote sensor. A numerical model of a MDCT is required to translate the air exhaust temperature to a Q. This report describes the MDCT model developed by the Problem Centered Integrated Analysis (PCIA) program that was designed to perform those computational tasks. The PCIA program is a collaborative effort between the Savannah River National Laboratory (SRNL), the Northrop-Grumman Corporation (NG) and the Aerospace Corporation (AERO).

  6. Alternative cooling tower water treatment methods

    SciTech Connect

    Wilsey, C.A.

    1996-11-01

    The factors that contribute to proper water balance include total alkalinity, calcium hardness, and pH. In order to keep the cooling tower from scaling or corroding, a manipulation of these components is often necessary. This has traditionally been achieved with the use of chemicals, including but not limited to the following: acid, soda ash, sodium bicarbonate, calcium bicarbonate, algicide, and bactericide. Extensive research has shown that a balanced water system can also be achieved by using the proper combination of copper with a known halogen. Microbiologists have determined that a small amount of copper, acting as a supplement to chlorine at 0.4 ppm, has the same efficiency as 2.0 ppm free chlorine. Therefore, by using the following combination of components and procedures, the desired results can still be achieved: production of copper compound ions as a supplement to the chemical regimen; analysis and manipulation of make-up water; the use of copper as a coagulant for reduction of scale; copper as a supplemental bacterial disinfectant; and copper as an algicide.

  7. Legionella species isolated from cooling towers in Kuala Lumpur.

    PubMed

    Ngeow, Y F; Tan, C H; Lim, S Y

    1992-03-01

    Three building complexes in Kuala Lumpur were surveyed for the presence of legionellae in cooling towers. The organisms were grown from 12 out of 46 samples of water collected from 30 towers. L. pneumophila serogroups 1 and 7 were the commonest serogroups isolated. None belonged to the Pontiac subgroup of L. pneumophila serogroup 1.

  8. In Hot Water: A Cooling Tower Case Study. Instructor's Manual

    ERIC Educational Resources Information Center

    Cochran, Justin; Raju, P. K.; Sankar, Chetan

    2005-01-01

    Vogtle Electric Generating Plant operated by Southern Nuclear Operating Company, a subsidiary of Southern Company, has found itself at a decision point. Vogtle depends on their natural draft cooling towers to remove heat from the power cycle. Depending on the efficiency of the towers, the cycle can realize more or less power output. The efficiency…

  9. In Hot Water: A Cooling Tower Case Study

    ERIC Educational Resources Information Center

    Cochran, Justin; Raju, P. K.; Sankar, Chetan

    2005-01-01

    Problem Statement: Vogtle Electric Generating Plant operated by Southern Nuclear Operating Company, a subsidiary of Southern Company, has found itself at a decision point. Vogtle depends on their natural draft cooling towers to remove heat from the power cycle. Depending on the efficiency of the towers, the cycle can realize more or less power…

  10. 2. Left side of Zinc Plant, from packless Cooling Tower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Left side of Zinc Plant, from packless Cooling Tower to midpoint of Cell Room, with majority of Upper Plant in view. View is to the east. - Sullivan Electrolytic Zinc Plant, Government Gulch, Kellogg, Shoshone County, ID

  11. 16. SOUTH SIDE OF STEAM PLANT COOLING TOWER IN OPERABLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. SOUTH SIDE OF STEAM PLANT COOLING TOWER IN OPERABLE CONDITION, WITH STACKS OF ORIGINAL BOILERS IN BACKGROUND. June 10, 1941 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

  12. 5. STEAM PLANT COOLING TOWER LOCATED WEST OF STEAM PLANT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. STEAM PLANT COOLING TOWER LOCATED WEST OF STEAM PLANT BUILDING, FROM SOUTH. SHOWS CURRENT LEVEL OF DISREPAIR. December 4, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

  13. 39. LOOKING SOUTH AT GAS COOLING TOWERS No. 1 (ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. LOOKING SOUTH AT GAS COOLING TOWERS No. 1 (ON RIGHT) AND No. 2, WITH DORR-OLIVER THICKENER IN FOREGROUND. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  14. 40. LOOKING SOUTHWEST AT GAS COOLING TOWERS No. 1 AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. LOOKING SOUTHWEST AT GAS COOLING TOWERS No. 1 AND No. 2, WITH DORR-OLIVER THICKENER IN FOREGROUND. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  15. 7. COOLING TOWER FROM ROOF. Hot Springs National Park, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. COOLING TOWER FROM ROOF. - Hot Springs National Park, Bathhouse Row, Quapaw Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  16. 10. STATIC TEST TOWER CLOSEUP OF COOLING PIPES OF FLAME ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. STATIC TEST TOWER CLOSE-UP OF COOLING PIPES OF FLAME DEFLECTOR PIT ON NORTH ELEVATION. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

  17. Use of cooling tower blow down in ethanol fermentation.

    PubMed

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

    2010-01-01

    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

  18. Environmental Impacts from the Operation of Cooling Towers at SRP

    SciTech Connect

    Smith, F.G. III

    2001-06-26

    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.

  19. Identification of cooling tower wood attack and methods of control

    SciTech Connect

    Song, P.; Trulear, M.G.

    1986-01-01

    Biological and chemical attack can greatly accelerate the deterioration of cooling tower wood. The damage, once inflicted, is irreversible and often results in premature and costly wood replacement. Biological attack is more serious than chemical, and is difficult to detect. Control of both types is essential for good tower maintenance A review of wood structures, types of attack and methods of control are presented. Effects of alkaline cooling water operation on wood deterioration are also discussed.

  20. Main photoautotrophic components of biofilms in natural draft cooling towers.

    PubMed

    Hauer, Tomáš; Čapek, Petr; Böhmová, Petra

    2016-05-01

    While photoautotrophic organisms are an important component of biofilms that live in certain regions of natural draft cooling towers, little is known about these communities. We therefore examined 18 towers at nine sites to identify the general patterns of community assembly in three distinct tower parts, and we examined how community structures differ depending on geography. We also compared the newly acquired data with previously published data. The bottom sections of draft cooling towers are mainly settled by large filamentous algae, primarily Cladophora glomerata. The central portions of towers host a small amount of planktic algae biomass originating in the cooling water. The upper fourths of towers are colonized by biofilms primarily dominated by cyanobacteria, e.g., members of the genera Gloeocapsa and Scytonema. A total of 41 taxa of phototrophic microorganisms were identified. Species composition of the upper fourth of all towers was significantly affected by cardinal position. There was different species composition at positions facing north compared to positions facing south. West- and east-facing positions were transitory and highly similar to each other in terms of species composition. Biofilms contribute to the degradation of paint coatings inside towers. PMID:26508444

  1. PBF Cooling Tower detail. Camera facing southwest into north side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower detail. Camera facing southwest into north side of Tower. Five horizontal layers of splash bars constitute fill decks, which will break up falling water into droplets, promoting evaporative cooling. Louvered faces, through which air enters tower, are on east and west sides. Louvers have been installed. Support framework for one of two venturi-shaped fan stacks (or "vents") is in center top. Orifices in hot basins (not in view) will distribute water over fill. Photographer: Kirsh. Date: May 15, 1969. INEEL negative no. 69-3032 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  2. Mathematical model and calculation of water-cooling efficiency in a film-filled cooling tower

    NASA Astrophysics Data System (ADS)

    Laptev, A. G.; Lapteva, E. A.

    2016-10-01

    Different approaches to simulation of momentum, mass, and energy transfer in packed beds are considered. The mathematical model of heat and mass transfer in a wetted packed bed for turbulent gas flow and laminar wave counter flow of the fluid film in sprinkler units of a water-cooling tower is presented. The packed bed is represented as the set of equivalent channels with correction to twisting. The idea put forward by P. Kapitsa on representation of waves on the interphase film surface as elements of the surface roughness in interaction with the gas flow is used. The temperature and moisture content profiles are found from the solution of differential equations of heat and mass transfer written for the equivalent channel with the volume heat and mass source. The equations for calculation of the average coefficients of heat emission and mass exchange in regular and irregular beds with different contact elements, as well as the expression for calculation of the average turbulent exchange coefficient are presented. The given formulas determine these coefficients for the known hydraulic resistance of the packed bed element. The results of solution of the system of equations are presented, and the water temperature profiles are shown for different sprinkler units in industrial water-cooling towers. The comparison with experimental data on thermal efficiency of the cooling tower is made; this allows one to determine the temperature of the cooled water at the output. The technical solutions on increasing the cooling tower performance by equalization of the air velocity profile at the input and creation of an additional phase contact region using irregular elements "Inzhekhim" are considered.

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

    SciTech Connect

    Pudelek, R. E.; Gilbert, W. C.

    2002-02-26

    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 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 ({approx}47%), wood ({approx}38%) and asbestos transite ({approx}14%). The remaining {approx}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

  4. Coagulation chemistries for silica removal from cooling tower water.

    SciTech Connect

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

    2010-02-01

    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.

  5. COOLING TOWER PUMP HOUSE, TRA606. THREE OF SIX SECTIONS OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    COOLING TOWER PUMP HOUSE, TRA-606. THREE OF SIX SECTIONS OF COOLING TOWER ARE VISIBLE ABOVE RAILING. PUMP HOUSE IN FOREGROUND IS ON SOUTH SIDE OF COOLING TOWER. NOTE THREE PIPES TAKING WATER FROM PUMP HOUSE TO HOT DECK OF COOLING TOWER. EMERGENCY WATER SUPPLY TOWER IS ALSO IN VIEW. INL NEGATIVE NO. 6197. Unknown Photographer, 6/27/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  6. ETR COOLING TOWER. PUMP HOUSE (TRA645) IN SHADOW OF TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ETR COOLING TOWER. PUMP HOUSE (TRA-645) IN SHADOW OF TOWER ON LEFT. AT LEFT OF VIEW, HIGH-BAY BUILDING IS ETR. ONE STORY ATTACHMENT IS ETR ELECTRICAL BUILDING. STACK AT RIGHT IS ETR STACK; MTR STACK IS TOWARD LEFT. CAMERA FACING NORTHEAST. INL NEGATIVE NO. 56-3799. Jack L. Anderson, 11/26/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  7. Pontiac fever outbreak associated with a cooling tower.

    PubMed Central

    Friedman, S; Spitalny, K; Barbaree, J; Faur, Y; McKinney, R

    1987-01-01

    In late April 1984, an outbreak of Pontiac fever was investigated in an office building in lower Manhattan (New York City). The outbreak was characterized by a high attack rate (78 per cent overall); the predominant symptoms were myalgias, chills, fatigue, fever, and headache. There was a clustering of cases in an office that was air cooled by a dedicated cooling tower separate from the remainder of the building. A high concentration of live L. Pneumophila cells in the cooling tower was quantified. Airborne spread via settle plates placed along the air intake system and within the office was demonstrated. Legionella pneumophila serogroup 1 antigen was found in the urine of two cases, and identical monoclonal antibody reactivity patterns of isolates from all sources was observed. Difficulty was experienced in eliminating the organism from the tower. PMID:3565648

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

    PubMed Central

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

    2015-01-01

    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

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

    PubMed

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

    2011-04-01

    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.

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

    PubMed

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

    2011-04-01

    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

  11. Effectiveness of bromicide against Legionella pneumophila in a cooling tower

    SciTech Connect

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

    1983-01-01

    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.

  12. PBF Cooling Tower under construction. Cold water basin is five ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower under construction. Cold water basin is five feet deep. Foundation and basin walls are reinforced concrete. Camera facing west. Pipe openings through wall in front are outlets for return flow of cool water to reactor building. Photographer: John Capek. Date: September 4, 1968. INEEL negative no. 68-3473 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  13. PBF Cooling Tower detail. Camera facing southwest. Wood fill rises ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower detail. Camera facing southwest. Wood fill rises from foundation piers of cold water basin. Photographer: Kirsh. Date: May 1, 1969. INEEL negative no. 69-2826 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  14. 40 CFR 63.1329 - Process contact cooling towers provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... associated with a vacuum system to a process contact cooling tower. (2) The owner or operator of a new... required in § 63.1335(e)(5), that contact condenser effluent associated with vacuum systems is not sent to... high viscosity multiple end finisher process, and who is subject or becomes subject to 40 CFR part...

  15. Program for monitoring LDB concentrations in cooling-tower waters

    SciTech Connect

    Porter, W.E.

    1983-01-01

    A brief description is presented in tabular form describing the program employed by the Industrial Hygiene Department of the Oak Ridge National Laboratory to monitor and control levels of Legionella in cooling tower waters. Guidelines are listed to protect personnel from an exposure that could lead to legionnaire's disease.

  16. Indiana State University Graduates to Advanced Plastic Cooling Towers

    ERIC Educational Resources Information Center

    Sullivan, Ed

    2012-01-01

    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…

  17. Cooling tower windage: a new aspect to environmental assessment

    SciTech Connect

    Taylor, F. G.; Park, S. H.

    1980-01-01

    Results of the several investigations provided quantitative estimates of windage from Oak Ridge Gaseous Diffusion Plant cooling towers. Windage water deposited on the ground has the potential to reach nearby streams through runoff. Windage deposited on moisture depleted soils would not be significant. During winter months at Oak Ridge soils generally have a high moisture content such that windage deposition could be quickly transported as runoff. It is during this time that cooling towers are sometimes operated without fan-induced draft. Since windage water contains the same hexavalent chromium concentration (9 ppM) as the recirculating cooling water system, the runoff stream from the K-892J tower constitues a NPDES violation as an unpermitted discharge. As a long-term abatement strategy, concrete aprons were constructed along each side of new cooling towers at the Paducah, Kentucky Gaseous Diffusion Plant. The maximum distance of windage impact is wind dependent. If apron construction is envisioned as an abatement strategy at Oak Ridge, the maximum distance of impact can be inferred graphically from the several points where windage (fans off) and drift (fans on) loss curves intersect under the different meteorological conditions. Once the hexavalent chromium laden runoff stream reaches Poplar Creek, it is diluted well below the standards for drinking water and poses little potential for biological effects to aquatic systems.

  18. 49. LOOKING NORTH AT EVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. LOOKING NORTH AT EVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS, WITH BLOW ENGINE HOUSE No. 3 ON RIGHT, AND FILTER CAKE HOUSE IN FOREGROUND. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  19. 40 CFR 63.1329 - Process contact cooling towers provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... high viscosity multiple end finisher process and who is subject or becomes subject to 40 CFR part 60... viscosity multiple end finisher process that utilizes a process contact cooling tower shall comply with... operators shall follow the procedures specified in 40 CFR 60.564(j)(1), except as provided in paragraph...

  20. Plan now for cold-weather operation of cooling towers

    SciTech Connect

    Michell, F.L.; Drew, D.H.

    1996-06-01

    This article describes what a midwestern utility has done to keep natural-draft towers running when faced with long bouts of high winds and single-digit temperatures. Severe ice buildup is the biggest threat. American Electric Power Co. (AEP) has six crossflow and eight counterflow natural-draft hyperbolic cooling towers in operation today. In the crossflow designs, subject of this discussion, the fill sections are more exposed to wind and cold. Their design circulating-water flow rates range from 220,000 to 600,000 gal/min; they serve 600-, 800-, and 1,300-MW coal-fired generating units. The towers are located in the Midwest and experience long periods of sub-freezing conditions during the winter months. High winds accompanied by single-digit temperatures often prevail for days at a time. During the record cold spell in January 1994, average temperatures as low as {minus}20 F occurred throughout AEP`s service area. Fill bypass systems have been incorporated into the design of AEP`s natural-draft cooling towers, and can pass between 25 and 50% of full-rated circulating-water flow. These systems prevent ice formation within the fill sections (heat-transfer media) by recirculating water directly to the tower cold-water basin during winter startup, when heat content of the circulating water is relatively low.

  1. Water distribution characteristics of spray nozzles in a cooling tower

    NASA Astrophysics Data System (ADS)

    Vitkovic, Pavol

    2015-05-01

    Water distribution characteristics of spray nozzles with spray plates used to distribute cooling water to the cooling fills in a cooling tower is one of the important parameters for the selection of nozzles. Water distribution characteristic describes the distribution of water from the axis of the nozzle along a fill. One of the parameters affecting the water distribution characteristic of the nozzle is airflow velocity of counter flow airstream. Water distribution characteristics are commonly measured using by a set of containers. The problem with this method of the measurement of characteristics is block of the airflow with collections of containers. Therefore, this work is using the visualization method.

  2. Experimental study of organically contaminated water in a cooling tower

    SciTech Connect

    Goldstein, D.J.; Aiyegbusi, O.

    1982-12-01

    A pilot model cooling system was set up and run so as to simultaneously cool heat exchanger tubes and biologically degrade phenol in the makeup water. The cooling tower used 1 ft/sup 2/ by 3 ft high, wetted film, polygrid, PVC packing. Water was circulated at 2.5 gpm (5.6 ft/sec) through two parallel heat exchange tubes immersed in a water bath controlled at 150/sup 0/F. Total water flow was 5 gpm/ft/sup 2/ of tower. Air was forced through the tower to give a liquid to gas mass ratio of 1.3. The cooling water circulated with an average temperature rise of 10/sup 0/F and an average approach to the air wet bulb temperature of 12/sup 0/F. Conclusions of this study are: (1) The pilot cooling tower was successfully operated to simultaneously cool and biodegrade phenol in the makeup water. Operation was not difficult and the experiments were reasonably reproducible. (2) An equivalent average concentration of phenol in the makeup water of 165 ppM (300 ppM BOD) should present little problem in commercial practice. An equivalent average concentration of up to 600 ppM phenol (1200 ppM BOD) may be acceptable in practice. Concentrations higher than 600 ppM phenol will cause such rapid biofouling and such rapid production of suspended solids in the circulating water as to be impractical. (3) More than 85 percent of the phenol removed was by biodegradation. Not more than 15 percent was stripped into the atmosphere. 12 figures, 12 tables.

  3. Susceptibility of Legionella pneumophila to three cooling tower microbicides

    SciTech Connect

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

    1981-01-01

    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 different, commercially available, cooling tower microbicides against L. pneumophila. Using two in vitro test systems, a combination of N-alkyl dimethyl benzyl ammonium chloride and bis (tri-n-butyltin) oxide was found to kill L. pneumophila at a concentration 25 times less than the minimum recommended use concentration, whereas N-alkyl 1,3-propanediamine and methylene bis(thiocyanate) were active at concentrations equal to or greater than the concentrations recommended for use by the manufacturer.

  4. Factors stimulating propagation of legionellae in cooling tower water

    SciTech Connect

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

    1992-04-01

    The authors survey of cooling tower water demonstrated that the highest density of legionellae, {ge}10{sup 4} CFU/100 ml, appeared in water containing protozoa, {ge}10{sup 2} MPN/100 ml, and heterotrophic bacteria, {ge}10{sup 6} CFU/100 ml, at water temperatures between 25 and 35C. Viable counts of legionellae were detected even in the winter samples, and propagation, up to 10{sup 5} CFU/100 ml, occurs in summer. The counts of legionellae correlated positively with increases in water temperature, pH, and protozoan counts, but not with heterotrophic bacterial counts. The water temperature of cooling towers may promote increases in the viable counts of legionellae, and certain microbes, e.g., protozoa or some heterotrophic bacteria, may be a factor stimulating the propagation of legionellae.

  5. Susceptibility of Legionella pneumophila to three cooling tower microbicides.

    PubMed Central

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

    1981-01-01

    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 different, commercially available, cooling tower microbicides against L. pneumophila. Using two in vitro test systems, a combination of N-alkyl dimethyl benzyl ammonium chloride and bis (tri-n-butyltin) oxide was found to kill L. pneumophila at a concentration 25 times less than the minimum recommended use concentration, whereas N-alkyl 1,3-propanediamine and methylene bis (thiocyanate) were active at concentrations equal to or greater than the concentrations recommended for use by the manufacturer. PMID:7224623

  6. Performance specification for control tower display systems

    NASA Astrophysics Data System (ADS)

    Aleva, Denise L.; Meyer, Frederick M.

    2003-09-01

    Personnel in airport control towers monitor and direct the takeoff of outgoing aircraft, landing of incoming aircraft and all movements of aircraft on the ground. Although the primary source of information for the Local Controller, Assistant Local Controller and the Ground Controller is the real world viewed through the windows of the control tower, electronic displays are also used to provide situation awareness. Due to the criticality of the work to be performed by the controllers and the rather unique environment of the air traffic control tower, display hardware standards, which have been developed for general use, are not directly applicable. The Federal Aviation Administration (FAA) requested assistance of Air Force Research Laboratory Human Effectiveness Directorate in producing a document which can be adopted as a Tower Display Standard usable by display engineers, human factors practitioners and system integrators. Particular emphasis was placed on human factors issues applicable to the control tower environment and controller task demands.

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

    PubMed

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

    2012-02-01

    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.

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

    PubMed

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

    2012-02-01

    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

  9. Effects of biocidal treatments to inhibit the growth of legionellae and other microorganisms in cooling towers.

    PubMed

    Yamamoto, H; Ezaki, T; Ikedo, M; Yabuuchi, E

    1991-01-01

    The effects of biocidal treatments for cooling towers were examined through the use of chemicals and ultraviolet irradiation to inhibit the growth of legionellae and other microorganisms. In the water of cooling towers without continuous biocidal treatments, heterotrophic bacteria and bacterivorous protozoan first appeared, and then legionellae increased up to 10(4) CFU/100 ml. When a UV sterilizer was connected to the cooling tower, the legionellae count was 1/10 or 1/100 of that in the nontreated tower water. In the water of towers supplemented continuously with the biocidal chemicals, legionellae were not found during a 4-month period. The biocidal treatments tested were proved to suppress the increase of legionellae in cooling-tower water, and thus are useful in preventing the outbreak of legionellosis due to inhalation of contaminated aerosol from the cooling tower system.

  10. Cooling tower irrigator layout with allowances for non-uniformity of the airflow velocity field

    NASA Astrophysics Data System (ADS)

    Pushnov, A. S.; Ryabushenko, A. S.

    2016-07-01

    This article covers the results of analysis of aerodynamic processes in the cooling tower irrigator and provides the approaches to optimal layout of preformed packing blocks (of the irrigator) developed based on these results. The analysis of the airflow velocity field in the cooling towers shows that the irrigation space can be broken down into the following zones: the peripheral zone of the cooling tower near the airblast windows, the zone near the cooling tower center, and the intermediate zone. Furthermore, the highest level of nonuniformity of the airflow velocity field in cooling towers is in the zone adjoining the tower's airblast windows. The proposed concept of the cooling tower irrigator's layout is made with allowances for the airflow velocity field characteristics in the cross-section of the irrigation space of the cooling tower. Based on this concept, we suggest that higher irrigator blocks should be placed in the zone of increased airflow consumption, which provides the possibility to enhance the hydraulic resistance and, respectively, decrease the gas flow velocity as well as to boost the efficiency of chilling the circulating water in the cooling tower. For this purpose, additional irrigator blocks can be of the same design as the main irrigator. As an option, it is possible to use blocks of the geometry and design other than the main irrigator block in the cooling tower.

  11. Wastewater reuse as cooling-tower makeup: Final report

    SciTech Connect

    Goldstein, D.; Wei, I.; Casana, J.

    1987-08-01

    The objectives of this program are to document electric utility experience and concerns on the use of municipal wastewater as makeup to cooling towers and to identify areas lacking sufficient information for their application as well as to identify problem areas. Current users of municipal wastewater in electric utility cooling towers have been contacted and the literature has been reviewed. In addition, literature on the reuse of industrial wastewater has been reviewed. The findings are summarized in this report with emphasis on the use of municipal wastewater in electric utility cooling towers. It was found that this practice has been going on for sufficient time at sufficient places that the problems are fairly well understood. Scale formation by calcium phosphate is a problem. It is controlled by pH reduction or by removal of phosphate and suggested techniques are given. Fouling by slime is a problem. It is controlled by heavy doses of chlorine and other biocides or by mechanical and other non-chemical means without use of any biocide. Foaming, corrosion and blowdown disposal are not problems. There are a number of problem areas where more information is desired to establish a higher level of confidence in using sewage water as makeup. Three areas of research are recommended: (1) a study comparing the technological and environmental problems and costs of various technologies used to control the formation of biological slime, (2) laboratory and pilot scale testing to verify the prediction techniques for phosphate precipitation, and (3) to determine whether the health hazards of using sewage water are worse than the use of normal waters.

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

    PubMed Central

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

    1991-01-01

    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 adelaidensis is proposed. PMID:2056032

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  14. Flue gas injection control of silica in cooling towers.

    SciTech Connect

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

    2011-06-01

    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.

  15. PBF Cooling Tower and it Auxiliary Building (PER624) to left ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower and it Auxiliary Building (PER-624) to left of tower. Camera facing west and the east louvered face of the tower. Details include secondary coolant water riser piping and flow control valves (butterfly valves) to distribute water evenly to all sections of tower. Photographer: Holmes. Date: May, 20, 1970. INEEL negative no. 70-2322 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

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

    SciTech Connect

    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

    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.

  17. Influence of Flow Rotation Within a Cooling Tower on the Aerodynamic Interaction with Crosswind Flow

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    Environmental crosswind changes the aerodynamic pattern inside a cooling tower, destroys uniform and axisymmetric distribution of flow at its inlet and outlet, and may degrade fill zone performance. In this paper, the effect of flow rotation in the over-shower zone of a natural draft cooling tower (NDCT) on the aerodynamic interaction with crosswind is studied numerically. The 3D geometry of an actual NDCT and three models of induced rotation velocity fields are utilized for simulation. It is demonstrated that flow rotation results in homogenization of the aerodynamic field in the over-shower zone. The inhomogeneity of the velocity field in the outlet cross section decreases linearly with rotation intensification. The effect of main stream switching under strong wind conditions is found. It is shown that even moderate flow rotation eliminates this effect.

  18. Analyzing the possibility of achieving more efficient cooling of water in the evaporative cooling towers of the Armenian NPP

    NASA Astrophysics Data System (ADS)

    Petrosyan, V. G.; Yeghoyan, E. A.

    2015-10-01

    The specific features of the service cooling water system used at the Armenian NPP and modifications made in the arrangement for supplying water to the water coolers in order to achieve more efficient cooling are presented. The mathematical model applied in carrying out the analyses is described, the use of which makes it possible to investigate the operation of parallel-connected cooling towers having different hydraulic and thermal loads. When the third standby cooling tower is put into operation (with the same flow rate of water supplied to the water coolers), the cooled water temperature is decreased by around 2-3°C in the range of atmospheric air temperatures 0-35°C. However, the introduced water distribution arrangement with a decreased spraying density has limitation on its use at negative outdoor air temperatures due to the hazard intense freezing of the fill in the cooling tower peripheral zone. The availability of standby cooling towers in the shutdown Armenian NPP power unit along with the planned full replacement of the cooling tower process equipment create good possibilities for achieving a deeper water cooling extent and better efficiency of the NPP. The present work was carried out with the aim of achieving maximally efficient use of existing possibilities and for elaborating the optimal cooling tower modernization version. Individual specific heat-andmass transfer processes in the chimney-type evaporative cooling towers are analyzed. An improved arrangement for distributing cooled water over the cooling tower spraying area (during its operation with a decreased flow rate) is proposed with the aim of cooling water to a deeper extent and preserving the possibility of using the cooling towers in winter. The main idea behind improving the existing arrangement is to exclude certain zones of the cooling tower featuring inefficient cooling from operation. The effectiveness of introducing the proposed design is proven by calculations (taking as an

  19. Startup of air-cooled condensers and dry cooling towers at low temperatures of the cooling air

    NASA Astrophysics Data System (ADS)

    Milman, O. O.; Ptakhin, A. V.; Kondratev, A. V.; Shifrin, B. A.; Yankov, G. G.

    2016-05-01

    The problems of startup and performance of air-cooled condensers (ACC) and dry cooling towers (DCT) at low cooling air temperatures are considered. Effects of the startup of the ACC at sub-zero temperatures are described. Different options of the ACC heating up are analyzed, and examples of existing technologies are presented (electric heating, heating up with hot air or steam, and internal and external heating). The use of additional heat exchanging sections, steam tracers, in the DCT design is described. The need for high power in cases of electric heating and heating up with hot air is noted. An experimental stand for research and testing of the ACC startup at low temperatures is described. The design of the three-pass ACC unit is given, and its advantages over classical single-pass design at low temperatures are listed. The formation of ice plugs inside the heat exchanging tubes during the start-up of ACC and DCT at low cooling air temperatures is analyzed. Experimental data on the effect of the steam flow rate, steam nozzle distance from the heat-exchange surface, and their orientation in space on the metal temperature were collected, and test results are analyzed. It is noted that the surface temperature at the end of the heat up is almost independent from its initial temperature. Recommendations for the safe start-up of ACCs and DCTs are given. The heating flow necessary to sufficiently heat up heat-exchange surfaces of ACCs and DCTs for the safe startup is estimated. The technology and the process of the heat up of the ACC with the heating steam external supply are described by the example of the startup of the full-scale section of the ACC at sub-zero temperatures of the cooling air, and the advantages of the proposed start-up technology are confirmed.

  20. The use of an electrical-fluid dynamic parameter in cooling tower

    SciTech Connect

    Sirena, J.A.

    1999-11-01

    An Electrical-Fluid Dynamic quality parameter is defined for a mechanical draft type cooling tower. It allows to evaluate the efficiency of the transformation of the electrical power input into kinetic energy of the air flow. It could also be used to calculate the active electrical power of the tower at different working conditions. Results obtained through tests in a small counterflow water cooling tower are shown.

  1. 40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 9 2012-07-01 2012-07-01 false Standard: Naphthalene processing, final... Standard: Naphthalene processing, final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions are allowed from naphthalene processing, final coolers and final-cooler cooling towers at coke...

  2. 40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 9 2014-07-01 2014-07-01 false Standard: Naphthalene processing, final... Standard: Naphthalene processing, final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions are allowed from naphthalene processing, final coolers and final-cooler cooling towers at coke...

  3. 40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 9 2013-07-01 2013-07-01 false Standard: Naphthalene processing, final... Standard: Naphthalene processing, final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions are allowed from naphthalene processing, final coolers and final-cooler cooling towers at coke...

  4. 40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standard: Naphthalene processing, final... Standard: Naphthalene processing, final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions are allowed from naphthalene processing, final coolers and final-cooler cooling towers at coke...

  5. 40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Standard: Naphthalene processing, final... Standard: Naphthalene processing, final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions are allowed from naphthalene processing, final coolers and final-cooler cooling towers at coke...

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

    NASA Astrophysics Data System (ADS)

    Hyhlík, T.

    2014-03-01

    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.

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

    SciTech Connect

    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.

    1983-02-01

    A new species of Legionella represented by 10 strains isolated from industrial cooling towers is described. 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 tested, required L-cysteine for primary isolation from animal tissues. L. oakridgensis was the only species of Legionella that failed to produce alkaline phosphatase at pH 8.5. In all other respects, it resembled other species of Legionella, including having a high content of branched-chain cellular fatty acids and being pathogenic for guinea pigs. These bacteria have not yet been associated with human disease, but they are potential causes of legionellosis.

  8. Synthetic image generation of factory stack and cooling tower plumes

    NASA Astrophysics Data System (ADS)

    Kuo, Shiao D.; Schott, John R.

    1997-07-01

    A new model for generating synthetic images of plumes has been developed using a radiometrically based ray-tracing algorithm. Existing plume models that describe the characteristics of the plume (constituents, concentration, particulate sizing, and temperature) are used to generate AutoCAD models for input into the code. The effects of scattered light using Mie theory and radiative transfer, as well as thermal self-emission/absorption from within the plume, are modeled for different regions of the plume. The ray-tracing accounts for direct sunlight, scattered skylight, reflected sunlight from the background, and thermal self-emission from both the atmosphere and background. Synthetic generated images of a cooling tower plume, composed of water droplets, and a factor stack plume, composed of methyl chloride, are produced for visible, MWIR, and LWIR bands. Images of the plume from different view angles are also produced. Observations are made on the interaction between the plume and its background and possible effects for remote sensing. Images are made of the methyl chloride plume in which the concentration and temperature are varied to determine the sensitivity of the radiance reaching the sensor.

  9. Vertical sampling flights in support of the 1981 ASCOT cooling tower experiments: field effort and data

    SciTech Connect

    Gay, G.T.

    1982-03-01

    During the month of August 1981, three nights of experimental sampling of tracers released into the cooling tower plume of a geothermal power plant were conducted. In these experiments a tethered balloon was used to lift a payload so as to obtain vertical profiles of the cooling tower plume and the entrained tracers. A description of the equipment used, the field effort and the data acquired are presented here.

  10. A comparison of legionella and other bacteria concentrations in cooling tower water

    SciTech Connect

    Cappabianca, R.M.; Jurinski, N.B.; Jurinski, J.B.

    1994-05-01

    A field study was conducted in which water samples collected from air conditioning cooling water reservoirs of high-rise buildings throughout an urban area were assayed for Legionella and for total bacteria. Buildings included within the study had ongoing biocidal treatment programs for the cooling towers. Separate sample analyses were performed to measure the viable colony concentrations of total bacteria and of Legionella in the process waters. The occurrence and viable counts of Legionella in 304 environmental water samples were determined by inoculating them onto plates of buffered charcoal yeast extract (BCYE) agar medium (a presumptive screening method). The samples were collected during summer months between July and September. BCYE plate cultures of 50 (16.4%) of the samples yielded Legionella with viable counts ranging from 2 to 608 colony forming units per milliliter. In the water samples, 281 (92.4%) yielded viable counts of bacteria that ranged from 9 to 1.2 x 10{sup 6} per milliliter. This study demonstrates that Legionella are commonly present in the water of air conditioning cooling towers and that there is no significant correlation between concurrently sampled culture plate counts of Legionella and total bacteria plate counts. Correspondingly, there is no demonstrated validity for use of total bacterial counts as an inferential surrogate for the concentration of Legionella in the water. 19 refs., 3 figs., 1 tab.

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

    PubMed

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

    2009-06-01

    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

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

    NASA Astrophysics Data System (ADS)

    Galegher, Sheila J.; Mann, Michael D.

    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 μg m -3 ammonia, 8000 μg m -3 phenol and 2500 μ m -3 methanol were detected in the lower exhaust.

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

    PubMed

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

    2014-01-01

    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

  14. Emissions characteristics of cooling towers using reclaimed wastewater in california. Final report, July 1979-July 1981

    SciTech Connect

    Rogozen, M.B.; Phillips, A.R.; Guttman, M.A.; Shokes, R.F.; Fargo, L.

    1981-08-11

    Present and planned use of reclaimed municipal wastewater, industrial process water, and geothermal condensate as makeup to cooling towers have raised questions about the potential for atmospheric emissions of pathogenic microorganisms, organic compounds, heavy metals, and other wastewater constituents. In this study, the makeup and circulating water of six towers were sampled and analyzed for indicator bacteria and virus, volatile and nonvolatile organic compounds, metals, and other components of potential concern. Further water sampling and exhaust air emissions tests were then conducted on four of the towers; for the microbiological emissions tests, a special isokinetic sampling device was developed and employed.

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

    PubMed

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

    2014-03-01

    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

  16. CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS

    SciTech Connect

    Lee, S.; Garrett, A.; Bollinger, J.

    2009-09-02

    Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some

  17. Concentration, serotypic profiles, and infectivity of Legionnaires' Disease bacteria populations in cooling towers

    SciTech Connect

    Tyndall, R.L.

    1982-01-01

    At the Philadelphia American Legion Convention in 1976 nearly two hundred people developed pulmonary infection. Of these, twenty-eight died. The causative bacterial agent was subsequently isolated and identified as a previously undiscovered human pathogen, that is, Legionnaires' Disease Bacterium (LDB). Currently it is estimated that over one hundred thousand cases of Legionella occur annually. Cooling towers have been shown to be the source of LDB in some of the outbreaks. Ecological information indicates that the bacteria are present in many natural waters. Moreover, there is strong evidence that algal products can stimulate the growth of LDB. Because cooling tower environments may be conducive for growth and/or dispersal of LDB, a survey of both industrial and air-conditioning cooling towers for the presence of LDB was undertaken.

  18. Alkaline approach to treating cooling towers for control of Legionella pneumophila

    SciTech Connect

    States, S.J.; Conley, L.F.; Towner, S.G.; Wolford, R.S.; Stephenson, T.E.; McNamara, M.; Wadowsky, R.M.; Yee, R.B.

    1987-08-01

    Earlier field and laboratory studies have shown that Legionella species survive and multiply in the pH range 5.5 to 9.2. Additionally, the technical feasibility of operating cooling towers at elevated alkalinities and pH has previously been documented by published guidelines. The guidelines indicate that these conditions facilitate corrosion control and favor chlorine persistence which enhances the effectiveness of continuous chlorination in biofouling control. This information suggest that control of Legionella species in cooling towers can be accomplished by operating the towers under alkaline conditions. To test this possibility, we collected water samples over a period of months from a hospital cooling tower. The samples were analyzed for a variety of chemical parameters. Subsamples were pasteurized and inoculated with non-agar-passaged Legionella pneumophila which had been maintained in tap water. Correlation of subsequent Legionella growth with corresponding pH and alkalinity values revealed statistically significant inverse associations. These data support the hypothesis that operating cooling towers outside of the optimal conditions for Legionella growth (e.g., at elevated alkalinities and a pH greater than 9) may be a useful approach to controlling growth in this habitat.

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

    SciTech Connect

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

    1997-11-01

    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.

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

    PubMed

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

    2013-01-01

    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.

  1. Evaluation and quantification of the impact of cooling tower emissions on indoor air quality

    SciTech Connect

    Vanderheyden, M.D.; Schuyler, G.D.

    1994-12-31

    Assessment of the potential impact of outdoor pollutant sources on indoor air quality through the reentrainment of pollutants vis-a-vis air-handling units, doorways, and windows has mainly focused on the evaluation of fume hood, boiler, diesel generator, and vehicular pollutant emissions. In recent years, however, gaseous and waterborne pollutants emitted from cooling towers have become an increasing source of concern. Chemicals such as biocides and corrosion and scale inhibitors are used to reduce and/or eliminate algae blooms, decrease bacterial and fungal growth, and reduce the corrosion of equipment. When added to the water used in cooling towers, these chemicals are emitted in both the gaseous phase and as pollutants dissolved in or suspended in water droplets. A qualitative evaluation of exhaust dispersion and droplet deposition rates associated with cooling towers is necessary when conducting an overall review of the environmental impact on indoor air quality. This paper identifies source emission rates to be used in assessing emissions of chemical additives in cooling towers, presents provisional design criteria for evaluating the impact of the chemical additives, and evaluates alternative methodologies for quantifying impact concentrations. These alternative assessment methodologies include numerical models, physical wind tunnel simulations, and computational fluid dynamics (CFD) simulations. Parameters used in comparing the methodologies include relative accuracy (order of magnitude) and modeling and simulation limitations.

  2. COOLING TOWER PUMP HOUSE, TRA606. ELEVATIONS, STRUCTURAL AND ROOF PLAN, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    COOLING TOWER PUMP HOUSE, TRA-606. ELEVATIONS, STRUCTURAL AND ROOF PLAN, DETAILS. BLAW-KNOX 3150-807-1, 2/1950. INL INDEX NO. 531-0607-00-098-100670. REV. 3. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  3. PBF Cooling Tower (PER720), and Auxiliary Building (PER624). Camera faces ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PBF Cooling Tower (PER-720), and Auxiliary Building (PER-624). Camera faces north to show south facades. Oblong vertical structure at left of center is weather shield for stairway. Date: August 2003. INEEL negative no. HD-35-10-4 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  4. ETR COOLING TOWER PUMP HOUSE, TRA645. FOUR SECONDARY COOLANT PUMPS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ETR COOLING TOWER PUMP HOUSE, TRA-645. FOUR SECONDARY COOLANT PUMPS ARE ARRANGED IN A ROW. IN REAR ARE THREE SHUTDOWN EMERGENCY PUMPS. INL NEGATIVE NO. 56-4176. Jack L. Anderson, Photographer, 12/21/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  5. Experimental optimization of cooling-tower-fan control based on field data. Master's thesis

    SciTech Connect

    Herman, D.L.

    1991-04-01

    Energy costs continue to play an important role in the decision-making process for building design and operation. Since the chiller, cooling tower fans, and associated pumps consume the largest fraction of energy in a heating, ventilating, and air-conditioning (HVAC) system, the control of these components is of major importance in determining building energy use. A significant control parameter for the chilled water system is the minimum entering condenser water set point temperature at which the cooling tower fans are cycled on and off, several studies have attempted to determine the optimum value for this minimum set point temperature, but direct measurements are not available to validate these studies. The purpose of this study was to experimentally determine the optimum minimum entering condenser water set point temperature from field data based on minimum energy consumption and to validate a chilled water system analytical model previously developed in earlier work. The total chiller system electrical consumption (chiller and cooling tower fan energy) was measured for four entering condensor water set point temperatures (70, 75, 80, and 85 deg F). The field results were compared to results obtained using an analytical model previously developed in a thesis entitled Optimized Design of a Commercial Building Chiller/Cooling Tower System, written by Joyce.

  6. ETR COOLING TOWER PUMP HOUSE, TRA645. PUMP HOUSE TAKES SHAPE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ETR COOLING TOWER PUMP HOUSE, TRA-645. PUMP HOUSE TAKES SHAPE. CAMERA FACES NORTH TOWARD ETR CONSTRUCTION AND MTR BEYOND. INL NEGATIVE NO. 56-2041. Jack L. Anderson, Photographer, 6/14/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

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

    PubMed

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

    2013-01-01

    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

  8. Nosocomial legionnaires' disease: epidemiologic demonstration of cooling towers as a source. [Legionella pneumophila

    SciTech Connect

    Garbe, P.L.; Davis, B.J.; Weisfeld, J.S.; Markowitz, L.; Miner, P. Garrity, F.; Barbaree, J.M.; Reingold, A.L.

    1985-07-26

    Investigation of a recent outbreak of nosocomial legionnaires' disease - initially thought to be due to the documented presence of Legionella pneumophila in the hospital potable water - showed that aerosols from one or more cooling towers were the actual source of infection. From June 27 to Aug 25, 1983, nosocomial legionnaires' disease developed in 15 persons at a hospital in Rhode Island. Twelve (80%) of 15 case-patients occupied rooms in building 1, unit B, compared with eight (28%) of 29 control patients (odds ratio = 10.8; 95% confidence interval = 1.4 to 85.6). Subsequent investigation demonstrated that water in a cooling tower located 100 ft upwind of unit B was heavily contaminated with L. pneumophila, serogroup 1, subgroup 1, 2, 4, 5. The same strain was isolated from nine of the patients and from the make-up water for the tower. Active surveillance during the ten months following decontamination of the cooling tower identified no additional cases of nosocomial legionnaires' disease, although the hospital potable water had not been treated. While recommendations have been made for controlling nosocomial legionnaires' disease by heating or hyperchlorination of hospital potable water, this outbreak demonstrates the importance of an adequate epidemiologic-environmental investigation in choosing the appropriate control strategy.

  9. A STUDY ON LEGIONELLA PNEUMOPHILA, WATER CHEMISTRY, AND ATMOSPHERIC CONDITIONS IN COOLING TOWERS AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Smith, C.; Brigmon, R.

    2009-10-20

    Legionnaires disease is a pneumonia caused by the inhalation of the bacterium Legionella pneumophila. The majority of illnesses have been associated with cooling towers since these devices can harbor and disseminate the bacterium in the aerosolized mist generated by these systems. Historically, Savannah River Site (SRS) cooling towers have had occurrences of elevated levels of Legionella in all seasons of the year and in patterns that are difficult to predict. Since elevated Legionella in cooling tower water are a potential health concern a question has been raised as to the best control methodology. In this work we analyze available chemical, biological, and atmospheric data to determine the best method or key parameter for control. The SRS 4Q Industrial Hygiene Manual, 4Q-1203, 1 - G Cooling Tower Operation and the SRNL Legionella Sampling Program, states that 'Participation in the SRNL Legionella Sampling Program is MANDATORY for all operating cooling towers'. The resulting reports include L. pneumophila concentration information in cells/L. L. pneumophila concentrations >10{sup 7} cells/L are considered elevated and unsafe so action must be taken to reduce these densities. These remedial actions typically include increase biocide addition or 'shocking'. Sometimes additional actions are required if the problem persists including increase tower maintenance (e.g. cleaning). Evaluation of 14 SRS cooling towers, seven water quality parameters, and five Legionella serogroups over a three-plus year time frame demonstrated that cooling tower water Legionella densities varied widely though out this time period. In fact there was no one common consistent significant variable across all towers. The significant factors that did show up most frequently were related to suspended particulates, conductivity, pH, and dissolved oxygen, not chlorine or bromine as might be expected. Analyses of atmospheric data showed that there were more frequent significant elevated Legionella

  10. Reuse of pretreated coal gasification condensate in a pilot scale cooling tower

    SciTech Connect

    Johnson, M.D.; Schweitzer, G.W.

    1987-01-01

    The recycle of wastewaters to cooling water systems is practiced in many industrial sectors. The Great Plains Gasification Plant (GPGP) located near Beulah, North Dakota, for example, was designed to reuse treated gas liquor as the primary source of makeup water. In other industrial plants, the concentration of contaminants in the makeup water is very low or the wastewater comprises only a small fraction of the total makeup to the cooling system. The Great Plains system is unique in that the stripped gas liquor (SGL) used as makeup contains relatively high concentrations of dissolved organics, ammonia and acid gases. In addition, the SGL constitutes over 90% of the total makeup to the system. The use of pretreated gas liquor in open, circulating cooling systems is an untried approach to wastewater recycle. The plant not only eliminates a large discharge problem but gains a valuable makeup source for the cooling towers. Because of the large heat duties for the cooling system in these types of plants and their location of regions of water shortages, this approach can be very beneficial. However, there are several environmental and operational concerns that have yet to be resolved. These include atmospheric emissions, fouling of heat transfer surfaces and cooling tower equipment, and excessive corrosion of system components.

  11. Tracking of smokestack and cooling tower plumes using wind measurements at different levels

    SciTech Connect

    Miller, R.L.; Patrinos, A.A.N.

    1980-08-01

    Relationships between cooling tower and smokestack plumes at the Bowen Electric Generating Plant in northwestern Georgia and wind direction measurements at levels from the surface at 850 mb (approx. 1.5 km) are examined. The wind measurements play an important role in estimating plume directions which in turn are utilized to establish control and target (upwind and downwind) areas for a study of plant-induced precipitation modification. Fifty-two plume observations were made during a three week period in December 1979. Results indicate that a windset (4.5 km from the plant) mounted at a level approximating that of the cooling tower plume is a better predictor of plume direction than surface windsets (1.0 km from the plant) or 850 mb level winds. However, an apparent topographical influence on the wind direction measurements at the plume-level windset site somewhat limits its plume tracking capability, at least for ambient winds from the SW quadrant.

  12. Reliability Analysis of Cooling Towers: Influence of Rebars Corrosion on Failure

    SciTech Connect

    Sudret, Bruno; Pendola, Maurice

    2002-07-01

    Natural-draught cooling towers are used in nuclear power plants as heat exchangers. These structures are submitted to environmental loads such as wind and thermal gradients that are stochastic in nature. A probabilistic framework has been developed by EDF (Electricite de France) for assessing the durability of such structures. In this paper, the corrosion of the rebars due to concrete carbonation and the corresponding weakening of the reinforced concrete sections is considered. Due to the presence of time in the definition of the limit state function associated with the loss of serviceability of the cooling tower, time-variant reliability analysis has to be used. A novel approach is proposed to take into account the random 'initiation time', which corresponds to the time necessary for the carbonation to attain the rebars. Results are given in terms of the probability of failure of the structure over its life time. (authors)

  13. Prevalence and Molecular Characteristics of Waterborne Pathogen Legionella in Industrial Cooling Tower Environments.

    PubMed

    Li, Lijie; Qin, Tian; Li, Yun; Zhou, Haijian; Song, Hongmei; Ren, Hongyu; Li, Liping; Li, Yongguang; Zhao, Dong

    2015-10-01

    Cooling towers are a source of Legionnaires' disease. It is important from a public health perspective to survey industrial cooling towers for the presence of Legionella. Prospective surveillance of the extent of Legionella pollution was conducted at factories in Shijiazhuang, China between March 2011 and September 2012. Overall, 35.7% of 255 industrial cooling tower water samples showed Legionella-positive, and their concentrations ranged from 100 Colony-Forming Units (CFU)/liter to 88,000 CFU/liter, with an average concentration of 9100 CFU/liter. A total of 121 isolates were obtained. All isolates were L. pneumophila, and the isolated serogroups included serogroups 1 (68 isolates, 56.2%), 6 (25, 20.7%), 5 (12, 9.9%), 8 (8, 6.6%), 3 (6, 5.0%) and 9 (2, 1.6%). All 121 isolates were analyzed by pulsed-field gel electrophoresis (PFGE) and 64 different patterns were obtained. All 121 isolates were analyzed sequence-based typing (SBT), a full 7-allele profile was obtained from 117 isolates. One hundred and seventeen isolates were divided into 49 sequence types. Two virulence genes, lvh and rtxA, are analyzed by polymerase chain reaction (PCR). 92.6% (112/121) and 98.3% (119/121) isolates carried lvh and rtxA respectively and 90.9% (110/121) of tested isolates carried both genes. Our results demonstrated high prevalence and genetic polymorphism of L. pneumophila in industrial cooling tower environments in Shijiazhang, China, and the SBT and virulence gene PCR results suggested that the isolates were pathogenic. Improved control and prevention strategies are urgently needed. PMID:26473896

  14. Prevalence and Molecular Characteristics of Waterborne Pathogen Legionella in Industrial Cooling Tower Environments

    PubMed Central

    Li, Lijie; Qin, Tian; Li, Yun; Zhou, Haijian; Song, Hongmei; Ren, Hongyu; Li, Liping; Li, Yongguang; Zhao, Dong

    2015-01-01

    Cooling towers are a source of Legionnaires’ disease. It is important from a public health perspective to survey industrial cooling towers for the presence of Legionella. Prospective surveillance of the extent of Legionella pollution was conducted at factories in Shijiazhuang, China between March 2011 and September 2012. Overall, 35.7% of 255 industrial cooling tower water samples showed Legionella-positive, and their concentrations ranged from 100 Colony-Forming Units (CFU)/liter to 88,000 CFU/liter, with an average concentration of 9100 CFU/liter. A total of 121 isolates were obtained. All isolates were L. pneumophila, and the isolated serogroups included serogroups 1 (68 isolates, 56.2%), 6 (25, 20.7%), 5 (12, 9.9%), 8 (8, 6.6%), 3 (6, 5.0%) and 9 (2, 1.6%). All 121 isolates were analyzed by pulsed-field gel electrophoresis (PFGE) and 64 different patterns were obtained. All 121 isolates were analyzed sequence-based typing (SBT), a full 7-allele profile was obtained from 117 isolates. One hundred and seventeen isolates were divided into 49 sequence types. Two virulence genes, lvh and rtxA, are analyzed by polymerase chain reaction (PCR). 92.6% (112/121) and 98.3% (119/121) isolates carried lvh and rtxA respectively and 90.9% (110/121) of tested isolates carried both genes. Our results demonstrated high prevalence and genetic polymorphism of L. pneumophila in industrial cooling tower environments in Shijiazhang, China, and the SBT and virulence gene PCR results suggested that the isolates were pathogenic. Improved control and prevention strategies are urgently needed. PMID:26473896

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

    PubMed

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

    2014-01-01

    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

  16. Field Scale Transport of Chromate in Groundwater From Cooling Tower Wastes

    NASA Astrophysics Data System (ADS)

    Gladding, S. M.; Hunt, J. R.

    2007-12-01

    Chromate (Cr(VI)) was used extensively in evaporative cooling systems to prevent corrosion and scale formation. Waters from the cooling systems were discharged to ponds that were intended as evaporation ponds, but there were instances where the wastewaters infiltrated into the soil and released chromate to groundwater. Cooling tower discharges containing chromate also have elevated salt concentrations compared to the ambient groundwater because of the intended evaporative cooling process. Density driven flow and emplacement of contaminated brines should thus be expected. This conceptual model is being evaluated by the analysis of field data at two natural gas compressor facilities in the deserts of southeastern California. These facilities continuously released chromate containing water to unlined evaporation ponds for more than a decade, and subsequent investigations have identified groundwater plumes containing chromate. At one site, extensive remediation over a 15 year period has limited the plume migration but has not reduced groundwater concentrations. At the other site, density-stratified flow is observed. While there are uncertainties in the amounts released, the data available at these sites suggest that remedial approaches based on groundwater extraction are not effective in removing the source of chromate contamination from emplaced pockets of highly concentrated cooling tower discharge. Long term data sets collected during site investigations and remediation are valuable sources of data on field scale transport of highly mobile contaminants such as chromate.

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

    PubMed

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

    2009-01-01

    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

  18. Susceptibilities of algae and Legionella pneumophila to cooling tower biocides

    SciTech Connect

    Soracco, R.J.; Gill, H.K.; Fliermans, C.B.; Pope, D.H.

    1983-04-01

    Nine algal strains and nine Legionella pneumophila strains were tested in laboratory culture for their susceptibility to inhibition by a variety of commercially available microbiocides. The responses ranged from ineffective to effective at 1/100 the manufacturers' recommended pulse doses. Tests were also performed to determine whether the action of the microbiocide was bacteriostatic or bacteriocidal.

  19. Investigation of Microbial Respirometry for Monitoring Natural Sulfide Abatement in Geothermal Cooling Tower Basins

    SciTech Connect

    Peter A. Pryfogle

    2005-09-01

    Geothermal plant operators are interested in investigating the ability of micro-organisms found in the cooling tower basin to metabolize and cycle sulfide to less toxic sulfur compounds. If the growth or activity of the organisms participating in sulfur-oxidation could be selectively enhanced, then hydrogen sulfide could be naturally abated in the cooling basin, substantially reducing the costs associated with the chemicals used for abatement. The use of respirometry has been proposed as a technique for monitoring the response of the microbial populations found in geothermal cooling towers to various conditions, including the addition of nutrients such as nitrogen and phosphorus. Respiro-metry is a manometric measurement of dissolved gases that are in equilibrium in a con-fined sample volume. Since microbes expire varying amounts of carbon dioxide or oxygen as they metabolize nutrients, this technique can be used to evaluate their activities in process streams. This report describes a series of experiments designed to determine the suitability of respirometry for tracking microbial activity for evaluating and enhancing natural abatement processes in geothermal cooling basins.

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

    PubMed

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

    2015-02-01

    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 < 0.05). In the two 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

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

    PubMed

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

    2015-02-01

    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 < 0.05). In the two 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.

  2. Wind tunnel experiments of cooling-tower plumes in the presence of cross flow

    NASA Astrophysics Data System (ADS)

    Andreopoulos, J.

    Measurements of velocity and temperature field and flow visualization results are reported for an ideal case of a cooling-tower plume in the presence of cross flow for various velocity ratios, densimetric Froude numbers, and Reynolds numbers. Coherent structures in the form of jet-like, wake-like or mushroom type of vortices have been observed. The type of the structures depends primarily on the velocity ratio. As the Reynolds number increases turbulent structures appear which carry vorticity of the same sign as the partner vortices in the low Reynolds number case. The measurements showed that there is a strong interaction between the bending over plume or jet and the wake of the cooling tower which is basically responsible for the downwash effect, which generally is quite strong at low velocity ratios and high Reynolds numbers. High turbulence intensities are produced on the wake of the tower for about 6 to 8 diameters. The plume is diluted faster as the velocity ratio and buoyancy increase.

  3. Technology to Facilitate the Use of Impaired Waters in Cooling Towers

    SciTech Connect

    Colborn, Robert

    2012-04-30

    The project goal was to develop an effective silica removal technology and couple that with existing electro-dialysis reversal (EDR) technology to achieve a cost effective treatment for impaired waters to allow for their use in the cooling towers of coal fired power plants. A quantitative target of the program was a 50% reduction in the fresh water withdrawal at a levelized cost of water of $3.90/Kgal. Over the course of the program, a new molybdenum-modified alumina was developed that significantly outperforms existing alumina materials in silica removal both kinetically and thermodynamically. The Langmuir capacity is 0.11g silica/g adsorbent. Moreover, a low cost recycle/regeneration process was discovered to allow for multiple recycles with minimal loss in activity. On the lab scale, five runs were carried out with no drop in performance between the second and fifth run in ability to absorb the silica from water. The Mo-modified alumina was successfully prepared on a multiple kilogram scale and a bench scale model column was used to remove 100 ppm of silica from 400 liters of simulated impaired water. Significant water savings would result from such a process and the regeneration process could be further optimized to reduce water requirements. Current barriers to implementation are the base cost of the adsorbent material and the fine powder form that would lead to back pressure on a large column. If mesoporous materials become more commonly used in other areas and the price drops from volume and process improvements, then our material would also lower in price because the amount of molybdenum needed is low and no additional processing is required. There may well be engineering solutions to the fine powder issue; in a simple concept experiment, we were able to pelletize our material with Boehmite, but lost performance due to a dramatic decrease in surface area.

  4. A petrolatum based system for control of external corrosion in, on and around cooling towers

    SciTech Connect

    Berry, M.A.; Steely, C.N.

    1986-01-01

    While it is true that the initial cost of a petroleum based system may be slightly higher than that of paint, this article maintains that the cost can be amortized over a 12 or 15-year period, or in some cases even longer. In service maintenance costs on a square foot per year basis, compared to all other alternatives are minimal. Petrolatum systems for external corrosion control on and around cooling towers have been effective service for over fifteen years, in diversified industrial environments that include oil refineries, chemical process plants, power utilities, hospital and university complexes and steel mills.

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

    SciTech Connect

    Paller, M.H.

    1991-02-01

    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.

  6. Chlorination/dechlorination studies relating to proposed cooling towers for K and C reactors

    SciTech Connect

    Wilde, E.W.

    1986-12-01

    The purpose of this study was to obtain data on the chlorination and dechlorination of the cooling water that is pumped through the C- and K-Reactor heat exchangers. More specifically, data were obtained on: (1) chlorine demand and dissipation rates; (2) the effectiveness of sodium sulfite as a dechlorinating agent; (3) the toxicity of chlorination and dechlorination on indigenous fish; (4) the effects of dechlorination on water quality; and (5) the comparative precision of three conventional residual chlorine detection methods. The study results strongly indicate that implementation of present plans for chlorination and dechlorination (with sodium sulfite) of SRP reactor cooling towers will cause no significant adverse environmental impacts and should not result in problems in meeting future regulatory guidelines for TRC. 9 figs., 11 tabs.

  7. Deposition and corrosion phenomena on aluminum surfaces under deluged dry cooling-tower condisions. Interim report

    SciTech Connect

    Wheeler, K.R.; May, R.P.; Douglas, J.G.; Tylczak, J.H.

    1981-07-01

    Deposition and corrosion on aluminum heat exchanger surfaces resulting from deluge in wet/dry cooling towers is simulated in a laboratory Corrosion/Deposition Loop (CDL). Heat exchanger deposition buildup was found to be linearly dependent on concentration factor and number of wet/dry cycles. Deionized water rising after deluge reduced rate of deposition. Laboratory data obtained from CDL relates directly to operation of the Advanced Concepts Test (ACT) demonstration cooling tower. Technology transferable to ACT shows that deposition from supersaturated solution can be effectively controlled by attention to water chemistry, pH, water conditioning, and good heat transfer design. The additional mechanism of deposition by water film evaporation is effectively managed by soft water rinsing and uniform surface wetting. Exposure of a model TRANE surface (the ACT wet/dry exchanger) produced short-term deposition extrapolating to 0.011 mm buildup in three years. Studies continue to verify 4X as maximum cycles of concentration through control of water chemistry and rinsing after deluge. Deluge water used at ACT facility is sufficiently aggressive to warrant use of Alclad to extend tube service life.

  8. Effects of FLONLIZER, ultraviolet sterilizer, on Legionella species inhabiting cooling tower water.

    PubMed

    Yamamoto, H; Urakami, I; Nakano, K; Ikedo, M; Yabuuchi, E

    1987-01-01

    Legionella pneumophila in sterile distilled water was not detected after ultraviolet irradiation by FLONLIZER, a new-type sterilizer, at a flow rate of 82.5 to 364.8 liters/hr. When irradiated by FLONLIZER at a flow rate of under 324.0 liters/hr, no viable cells of legionellae, other heterotrophic bacteria and bacterivorous protozoa were detected in the cooling tower water, which was found to contain L. pneumophila. No viable cells of L. pneumophila and L. bozemanii suspended in sterile distilled water were detected after the irradiation with UV-doses of over 6.16 X 10(3) micro W.sec/cm2. At the irradiation of low UV-doses under 1.06 X 10(4) micro W.sec/cm2, the viable count of legionellae recuperated by photoreactivation from UV-damage increased with the exposure time under a white fluorescent lamp. However, in the samples irradiated with UV-doses of over 3.52 X 10(4) micro W.sec/cm2, equal to the FLONLIZER, legionellae did not recuperate even after 18 hr illumination with a white fluorescent lamp. FLONLIZER is thus expected to act as a sterilizer which can control the legionellae inhabiting cooling tower systems placed in outdoor space.

  9. Wastewater reuse in a cascade based system of a petrochemical industry for the replacement of losses in cooling towers.

    PubMed

    Hansen, Everton; Rodrigues, Marco Antônio Siqueira; Aquim, Patrice Monteiro de

    2016-10-01

    This article discusses the mapping of opportunities for the water reuse in a cascade based system in a petrochemical industry in southern Brazil. This industrial sector has a large demand for water for its operation. In the studied industry, for example, approximately 24 million cubic meters of water were collected directly from the source in 2014. The objective of this study was to evaluate the implementation of the reuse of water in cascade in a petrochemical industry, focusing on the reuse of aqueous streams to replenish losses in the cooling towers. This is an industrial scale case study with real data collected during the years 2014 and 2015. Water reuse was performed using heuristic approach based on the exploitation of knowledge acquired during the search process. The methodology of work consisted of the construction of a process map identifying the stages of production and water consumption, as well as the characterization of the aqueous streams involved in the process. For the application of the industrial water reuse as cooling water, mass balances were carried out considering the maximum concentration levels of turbidity, pH, conductivity, alkalinity, calcium hardness, chlorides, sulfates, silica, chemical oxygen demand and suspended solids as parameters turbidity, pH, conductivity, alkalinity, calcium hardness, chlorides, sulfates, silica, chemical oxygen demand and suspended solids as parameters. The adopted guideline was the fulfillment of the water quality criteria for each application in the industrial process. The study showed the feasibility for the reuse of internal streams as makeup water in cooling towers, and the implementation of the reuse presented in this paper totaled savings of 385,440 m(3)/year of water, which means a sufficient volume to supply 6350 inhabitants for a period of one year, considering the average water consumption per capita in Brazil; in addition to 201,480 m(3)/year of wastewater that would no longer be generated.

  10. Wastewater reuse in a cascade based system of a petrochemical industry for the replacement of losses in cooling towers.

    PubMed

    Hansen, Everton; Rodrigues, Marco Antônio Siqueira; Aquim, Patrice Monteiro de

    2016-10-01

    This article discusses the mapping of opportunities for the water reuse in a cascade based system in a petrochemical industry in southern Brazil. This industrial sector has a large demand for water for its operation. In the studied industry, for example, approximately 24 million cubic meters of water were collected directly from the source in 2014. The objective of this study was to evaluate the implementation of the reuse of water in cascade in a petrochemical industry, focusing on the reuse of aqueous streams to replenish losses in the cooling towers. This is an industrial scale case study with real data collected during the years 2014 and 2015. Water reuse was performed using heuristic approach based on the exploitation of knowledge acquired during the search process. The methodology of work consisted of the construction of a process map identifying the stages of production and water consumption, as well as the characterization of the aqueous streams involved in the process. For the application of the industrial water reuse as cooling water, mass balances were carried out considering the maximum concentration levels of turbidity, pH, conductivity, alkalinity, calcium hardness, chlorides, sulfates, silica, chemical oxygen demand and suspended solids as parameters turbidity, pH, conductivity, alkalinity, calcium hardness, chlorides, sulfates, silica, chemical oxygen demand and suspended solids as parameters. The adopted guideline was the fulfillment of the water quality criteria for each application in the industrial process. The study showed the feasibility for the reuse of internal streams as makeup water in cooling towers, and the implementation of the reuse presented in this paper totaled savings of 385,440 m(3)/year of water, which means a sufficient volume to supply 6350 inhabitants for a period of one year, considering the average water consumption per capita in Brazil; in addition to 201,480 m(3)/year of wastewater that would no longer be generated. PMID

  11. Molecular characterization of viable Legionella spp. in cooling tower water samples by combined use of ethidium monoazide and PCR.

    PubMed

    Inoue, Hiroaki; Fujimura, Reiko; Agata, Kunio; Ohta, Hiroyuki

    2015-01-01

    Viable Legionella spp. in environmental water samples were characterized phylogenetically by a clone library analysis combining the use of ethidium monoazide and quantitative PCR. To examine the diversity of Legionella spp., six cooling tower water samples and three bath water samples were collected and analyzed. A total of 617 clones were analyzed for their 16S rRNA gene sequences and classified into 99 operational taxonomic units (OTUs). The majority of OTUs were not clustered with currently described Legionella spp., suggesting the wide diversity of not-yet-cultured Legionella groups harbored in cooling tower water environments. PMID:25736979

  12. Molecular characterization of viable Legionella spp. in cooling tower water samples by combined use of ethidium monoazide and PCR.

    PubMed

    Inoue, Hiroaki; Fujimura, Reiko; Agata, Kunio; Ohta, Hiroyuki

    2015-01-01

    Viable Legionella spp. in environmental water samples were characterized phylogenetically by a clone library analysis combining the use of ethidium monoazide and quantitative PCR. To examine the diversity of Legionella spp., six cooling tower water samples and three bath water samples were collected and analyzed. A total of 617 clones were analyzed for their 16S rRNA gene sequences and classified into 99 operational taxonomic units (OTUs). The majority of OTUs were not clustered with currently described Legionella spp., suggesting the wide diversity of not-yet-cultured Legionella groups harbored in cooling tower water environments.

  13. High Performance Torso Cooling Garment

    NASA Technical Reports Server (NTRS)

    Conger, Bruce; Makinen, Janice

    2016-01-01

    The concept proposed in this paper is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area, which could facilitate removal of LCVG tubing from the arms and legs, thereby increasing suited crew member mobility. EVA space suit mobility in micro-gravity is challenging, and it becomes even more challenging in the gravity of Mars. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased. This increase in efficiency could provide the required liquid cooling via torso tubing only; no arm or leg LCVG tubing would be required. Benefits of this approach include increased crewmember mobility, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development. This report describes analysis and test activities performed to evaluate the potential improvements to the thermal performance of the LCVG. Analyses evaluated potential tube shapes for improving the thermal performance of the LCVG. The analysis results fed into the selection of flat flow strips to improve thermal contact with the skin of the suited test subject. Testing of small segments was performed to compare thermal performance of the tubing approach of the current LCVG to the flat flow strips proposed as the new concept. Results of the testing is presented along with recommendations for future development of this new concept.

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

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

    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.

  15. A mechanistic approach to the development of chemical solutions for fouling of cooling tower film fills

    SciTech Connect

    Gill, J.S.; Yorke, M.A.; Donlan, R.M.; Gibbon, D.L.; McClung, B.

    1995-02-01

    Since the 1980`s reported incidents of cooling tower film fill fouling have continually increased and many utilities have sought chemical treatment solution for their fouling problems. Specialty chemical companies have been called upon to research the problems and to provide programs and products that address this pressing issue. The process of surface fouling of high efficiency film fill is a complex problem due to the multiple components involved in the fouling. An in depth understanding of the problem is necessary to determine effective treatment approaches. This study defines the mechanisms of film fill fouling by examination of microorganisms, silt particles and inorganic minerals in the fouling process. The investigation of chemical treatment approaches for the effective control of fouling based on the fouling mechanisms also are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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%).

  17. Free-living amoebae and their associated bacteria in Austrian cooling towers: a 1-year routine screening.

    PubMed

    Scheikl, Ute; Tsao, Han-Fei; Horn, Matthias; Indra, Alexander; Walochnik, Julia

    2016-09-01

    Free-living amoebae (FLA) are widely spread in the environment and known to cause rare but often serious infections. Besides this, FLA may serve as vehicles for bacterial pathogens. In particular, Legionella pneumophila is known to replicate within FLA thereby also gaining enhanced infectivity. Cooling towers have been the source of outbreaks of Legionnaires' disease in the past and are thus usually screened for legionellae on a routine basis, not considering, however, FLA and their vehicle function. The aim of this study was to incorporate a screening system for host amoebae into a Legionella routine screening. A new real-time PCR-based screening system for various groups of FLA was established. Three cooling towers were screened every 2 weeks over the period of 1 year for FLA and Legionella spp., by culture and molecular methods in parallel. Altogether, 83.3 % of the cooling tower samples were positive for FLA, Acanthamoeba being the dominating genus. Interestingly, 69.7 % of the cooling tower samples were not suitable for the standard Legionella screening due to their high organic burden. In the remaining samples, positivity for Legionella spp. was 25 % by culture, but overall positivity was 50 % by molecular methods. Several amoebal isolates revealed intracellular bacteria.

  18. Cooling tower with concrete support structure, fiberglass panels, and a fan supported by the liquid distribution system

    SciTech Connect

    Bardo, C. J.; Clark Jr., J. L.; Dylewski, A. J.; Seawell, J. Q.

    1985-09-24

    A liquid cooling tower includes precast concrete support legs and cross beams and fiberglass reinforced polyester resin side and top panels. A liquid distribution system is supplied with liquid by a vertically extending main pipe, and a fan and fan motor are supported by the main pipe.

  19. Community outbreak of Legionnaires' disease: an investigation confirming the potential for cooling towers to transmit Legionella species.

    PubMed

    Keller, D W; Hajjeh, R; DeMaria, A; Fields, B S; Pruckler, J M; Benson, R S; Kludt PE Lett, S M; Mermel, L A; Giorgio, C; Breiman, R F

    1996-02-01

    In August and September 1993, we investigated an outbreak of legionnaires' disease in Fall River, Massachusetts, that involved 11 persons; the attack rate was highest in Flint, a community of Fall River. All cases were infected with Legionella pneumophila serogroup 1 (Lp-1). A case-control study revealed that cases were more likely than matched controls to have visited sites in neighborhood A of Flint. Environmental sampling in Flint found that four of nine aerosol-producing devices sampled contained legionellae; only two, conjoined cooling towers on building A, contained Lp-1. Three independent methods of subtyping--monoclonal antibody subtyping, arbitrary primer polymerase chain reaction, and pulsed-field gel electrophoresis--revealed that Lp-1 isolates from three cases with culture-positive legionnaires' disease matched those from the cooling towers on building A. Water samples from the homes of cases with culture-positive legionnaires' disease contained no legionellae. The results of this epidemiologic and laboratory investigation indicate that the cooling towers on building A were the source of the outbreak of legionnaires' disease and confirm the importance of cooling towers in the transmission of legionnaires' disease.

  20. Free-living amoebae and their associated bacteria in Austrian cooling towers: a 1-year routine screening.

    PubMed

    Scheikl, Ute; Tsao, Han-Fei; Horn, Matthias; Indra, Alexander; Walochnik, Julia

    2016-09-01

    Free-living amoebae (FLA) are widely spread in the environment and known to cause rare but often serious infections. Besides this, FLA may serve as vehicles for bacterial pathogens. In particular, Legionella pneumophila is known to replicate within FLA thereby also gaining enhanced infectivity. Cooling towers have been the source of outbreaks of Legionnaires' disease in the past and are thus usually screened for legionellae on a routine basis, not considering, however, FLA and their vehicle function. The aim of this study was to incorporate a screening system for host amoebae into a Legionella routine screening. A new real-time PCR-based screening system for various groups of FLA was established. Three cooling towers were screened every 2 weeks over the period of 1 year for FLA and Legionella spp., by culture and molecular methods in parallel. Altogether, 83.3 % of the cooling tower samples were positive for FLA, Acanthamoeba being the dominating genus. Interestingly, 69.7 % of the cooling tower samples were not suitable for the standard Legionella screening due to their high organic burden. In the remaining samples, positivity for Legionella spp. was 25 % by culture, but overall positivity was 50 % by molecular methods. Several amoebal isolates revealed intracellular bacteria. PMID:27177720

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

    PubMed

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

    2010-03-01

    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

  2. Legionnaires' Disease Outbreak at a Long-Term Care Facility Caused by a Cooling Tower Using an Automated Disinfection System--Ohio, 2013.

    PubMed

    Quinn, Celia; Demirjian, Alicia; Watkins, Louise Francois; Tomczyk, Sara; Lucas, Claressa; Brown, Ellen; Kozak-Muiznieks, Natalia; Benitez, Alvaro; Garrison, Laurel E; Kunz, Jasen; Brewer, Scott; Eitniear, Samantha; DiOrio, Mary

    2015-12-01

    On July 9, 2013, an outbreak of Legionnaires' disease (LD) was identified at Long-Term Care Facility A in central Ohio. This article describes the investigation of the outbreak and identification of the outbreak source, a cooling tower using an automated biocide delivery system. In total, 39 outbreak LD cases were identified; among these, six patients died. Water samples from a cooling tower were positive for Legionella pneumophila serogroup 1, reactive to monoclonal antibody 2, with matching sequence type to a patient isolate. An electronic control system turned off cooling tower pumps during low-demand periods, preventing delivery of disinfectant by a timed-release system, and leading to amplification of Legionella in the cooling tower. Guidelines for tower maintenance should address optimal disinfection when using automated systems. PMID:26738313

  3. Survey of cooling towers within Oak Ridge Operations for the presence of the Legionnaire's Disease Bacterium. Environmental Sciences Division Publication No. 1731

    SciTech Connect

    Tyndall, R.L.; Domingue, E.L.

    1982-03-01

    A preliminary survey of Oak Ridge Operations (ORO) facilities was made to determine if the Legionnaire's Disease Bacterium (LDB) was present in cooling tower water. Total numbers of the bacterium per liter of water were determined, and in some cases isolation of infectious bacteria was attempted. Most of the test cooling towers from the X-10 site had concentrations of LDB in excess of 1 x 10/sup 6//L of basin water. Infectious LDB was isolated from one of the water samples. Some towers from the Y-12 site were also found to contain in excess of 1 x 10/sup 6/ LDB/L of water. With two exceptions, tower samples from the K-25, Portsmouth, and Paducah sites had less than 1 x 10/sup 6/ LDB/L of water. Except for the ORAU Medical Division cooling tower, ORAU cooling towers also had less than 1 x 10/sup 6/ LDB/L of water. The results indicate that chromate treatment is generally effective in preventing high levels of LDB. The results also suggest the desirability of a continuing monitoring program for ORO cooling towers so that concentrations of LDB in the towers can be controlled at reduced levels.

  4. Performance evaluation of an active solar cooling system utilizing low cost plastic collectors and an evaporatively-cooled absorption chiller

    NASA Astrophysics Data System (ADS)

    Lof, G. O.; Westhoff, M. A.; Karaki, S.

    1984-02-01

    During the summer of 1982, air conditioning in Solar House 3 at Colorado State University was provided by an evaporatively-cooled absorption chiller. The single-effect lithium bromide chiller is an experimental three-ton unit from which heat is rejected by direct evaporative cooling of the condenser and absorber walls, thereby eliminating the need for a separate cooling tower. Domestic hot water was also provided by use of a double-walled heat exchanger and 80-gal hot water tank. A schematic of the system is given. Objectives of the project were: (1) evaluation of system performance over the course of one cooling season in Fort Collins, Colorado; (2) optimization of system operation and control; (3) development of a TRNSYS compatible model of the chiller; and (4) determination of cooling system performance in several U.S. climates by use of the model.

  5. AUTOMATED DEAD-END ULTRAFILTRATION FOR ENHANCED SURVEILLANCE OF LEGIONELLA 2 PNEUMOPHILA AND LEGIONELLA SPP. IN COOLING TOWER WATERS

    SciTech Connect

    Brigmon, R.; Leskinen, S.; Kearns, E.; Jones, W.; Miller, R.; Betivas, C.; Kingsley, M.; Lim, D.

    2011-10-10

    Detection of Legionella pneumophila in cooling towers and domestic hot water systems involves concentration by centrifugation or membrane filtration prior to inoculation onto growth media or analysis using techniques such as PCR or immunoassays. The Portable Multi-use Automated Concentration System (PMACS) was designed for concentrating microorganisms from large volumes of water in the field and was assessed for enhancing surveillance of L. pneumophila at the Savannah River Site, SC. PMACS samples (100 L; n = 28) were collected from six towers between August 2010 and April 2011 with grab samples (500 ml; n = 56) being collected before and after each PMACS sample. All samples were analyzed for the presence of L. pneumophila by direct fluorescence immunoassay (DFA) using FITC-labeled monoclonal antibodies targeting serogroups 1, 2, 4 and 6. QPCR was utilized for detection of Legionella spp. in the same samples. Counts of L. pneumophila from DFA and of Legionella spp. from qPCR were normalized to cells/L tower water. Concentrations were similar between grab and PMACS samples collected throughout the study by DFA analysis (P = 0.4461; repeated measures ANOVA). The same trend was observed with qPCR. However, PMACS concentration proved advantageous over membrane filtration by providing larger volume, more representative samples of the cooling tower environment, which led to reduced variability among sampling events and increasing the probability of detection of low level targets. These data highlight the utility of the PMACS for enhanced surveillance of L. pneumophila by providing improved sampling of the cooling tower environment.

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

    SciTech Connect

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

    1985-02-01

    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, IL, and Los Angeles, CA, during outbreaks of nosocomial legionellosis. The fifth strain was isolated from water collected from an industrial cooling tower in Jamestown, NY. The strains exhibited biochemical reactions typical of Legionella species and were gram-negative motile rods which grew on buffered charcoal-yeast extract agar but not on blood agar, required cysteine, and were catalase positive, urease negative, nitrate negative, hippurate negative, and nonfermentative. All strains were positive for oxidase and beta-lactamase and produced a brown, diffusible pigment. The fatty-acid composition and ubiquinone content of these strains were consistent with those of other Legionella species. Direct fluorescent-antibody examination of the five strains with conjugates to previously described Legionella species demonstrated no cross-reactions except with the conjugates to L. longbeachae serogroup 2 and L. bozemannii serogroup 2. Four strains gave a 4+ reaction to the L. longbeachae serogroup 2 conjugate and the fifth strain gave a 1+ reaction. Each of the five strains gave a 4+ reaction with the conjugate to L. bozemanii serogroup 2. DNAs from the five strains were highly related (84 to 99%) and showed 5 to 57% relatedness to other Legionella species. These strains constitute a new species in the genus Legionella, and the name Legionella anisa sp. nov. is proposed.

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

    PubMed

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

    2007-11-15

    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

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

    SciTech Connect

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

    1983-03-01

    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.

  9. Applicability of a ``shower`` passive cooling tower in a hot dry climate

    SciTech Connect

    Givoni, B.; Al-Hemiddi, N.

    1995-11-01

    This cooling system has originally been developed by Givoni for cooling outdoor rest areas for the EXPO`92 in Seville, Spain. However, it can also be applied, and has been tested, as a cooling system for building and enclosed and shaded courtyards. It consists of an open shaft with showers at the top and a collecting ``pond`` at the bottom. Water is recirculated by a pump. The falling water entrain a large volume of air, creating a flow of cooled air down the shaft and into a building. A wind catcher can be installed above the shaft to enhance the air flow rate. The paper presents data on the performance of the system, tested by Al Hemiddi, including experimental data obtained first in a ``patio`` test cell at UCLA in Los Angeles, and later in a full size room in Riyadh, Saudi Arabia. The testing in Riyadh has demonstrated that with outdoor air maximum temperature of about 45 C the indoor air maximum of the cooled room was bout 29 C. This system can use brackish and sea water, in addition to fresh water. Thus it is applicable and capable of providing indoor comfort even in very hot desert regions, where any kind of water, even sea water, is available.

  10. High temperature performance of high-efficiency, multi-layer solar selective coatings for tower applications

    DOE PAGES

    Gray, M. H.; Tirawat, R.; Kessinger, K. A.; Ndione, P. F.

    2015-05-01

    The roadmap to next-generation concentrating solar power plants anticipates a progression to central towers with operating temperatures in excess of 650°C. These higher temperatures are required to drive higher power-cycle efficiencies, resulting in lower cost energy. However, these conditions also place a greater burden on the materials making up the receiver. Any novel absorber material developed for next-generation receivers must be stable in air, cost effective, and survive thousands of heating and cooling cycles. The collection efficiency of a power tower plant can be increased if the energy absorbed by the receiver is maximized while the heat loss from themore » receiver to the environment is minimized. Thermal radiation losses can be significant (>7% annual energy loss) with receivers at temperatures above 650°C. We present progress toward highly efficient and durable solar selective absorbers (SSAs) intended for operating temperatures from 650°C to 1000°C. Selective efficiency (ηsel) is defined as the energy retained by the absorber, accounting for both absorptance and emittance, relative to the energy incident on the surface. The low emittance layers of multilayer SSAs are binary compounds of refractory metals whose material properties indicate that coatings formed of these materials should be oxidation resistant in air to 800-1200°C. On this basis, we initially developed a solar selective coating for parabolic troughs. This development has been successfully extended to meet the absorptance and emittance objectives for the more demanding, high temperature regime. We show advancement in coating materials, processing and designs resulting in the initial attainment of target efficiencies ηsel > 0.91 for proposed tower conditions. Additionally, spectral measurements show that these coatings continue to perform at targeted levels after cycling to temperatures of 1000°C in environments of nitrogen and forming gas.« less

  11. High temperature performance of high-efficiency, multi-layer solar selective coatings for tower applications

    SciTech Connect

    Gray, M. H.; Tirawat, R.; Kessinger, K. A.; Ndione, P. F.

    2015-05-01

    The roadmap to next-generation concentrating solar power plants anticipates a progression to central towers with operating temperatures in excess of 650°C. These higher temperatures are required to drive higher power-cycle efficiencies, resulting in lower cost energy. However, these conditions also place a greater burden on the materials making up the receiver. Any novel absorber material developed for next-generation receivers must be stable in air, cost effective, and survive thousands of heating and cooling cycles. The collection efficiency of a power tower plant can be increased if the energy absorbed by the receiver is maximized while the heat loss from the receiver to the environment is minimized. Thermal radiation losses can be significant (>7% annual energy loss) with receivers at temperatures above 650°C. We present progress toward highly efficient and durable solar selective absorbers (SSAs) intended for operating temperatures from 650°C to 1000°C. Selective efficiency (ηsel) is defined as the energy retained by the absorber, accounting for both absorptance and emittance, relative to the energy incident on the surface. The low emittance layers of multilayer SSAs are binary compounds of refractory metals whose material properties indicate that coatings formed of these materials should be oxidation resistant in air to 800-1200°C. On this basis, we initially developed a solar selective coating for parabolic troughs. This development has been successfully extended to meet the absorptance and emittance objectives for the more demanding, high temperature regime. We show advancement in coating materials, processing and designs resulting in the initial attainment of target efficiencies ηsel > 0.91 for proposed tower conditions. Additionally, spectral measurements show that these coatings continue to perform at targeted levels after cycling to temperatures of 1000°C in environments of nitrogen and forming gas.

  12. Legionella detection and subgrouping in water air-conditioning cooling tower systems in Kuwait.

    PubMed

    Al-Matawah, Qadreyah; Al-Zenki, Sameer; Al-Azmi, Ahmad; Al-Waalan, Tahani; Al-Salameen, Fadila; Hejji, Ahmad Ben

    2015-07-01

    The main aim of the study was to test for the presence of Legionnaires' disease-causing microorganisms in air-conditioned buildings in Kuwait using molecular technologies. For this purpose, 547 samples were collected from 38 cooling towers for the analysis of Legionella pneumophila. These samples included those from water (n = 178), air (n = 231), and swabs (n = 138). Out of the 547 samples, 226 (41%) samples were presumptive positive for L. pneumophila, with L. pneumophila viable counts in the positive water samples ranging from 1 to 88 CFU/ml. Of the Legionella culture-positive samples, 204 isolates were examined by latex agglutination. These isolates were predominately identified as L. pneumophila serogroup (sg) 2-14. Using the Dresden panel of monoclonal antibodies, 74 representatives isolates were further serogrouped. Results showed that 51% of the isolates belonged to serogroup 7 followed by 1 (18%) and 3 (18%). Serogroups 4 (4%) and 10 (7%) were isolated at a lower frequency, and two isolates could not be assigned to a serogroup. These results indicate the wide prevalence of L. pneumophila serogroup 7 as the predominant serogroup at the selected sampling sites. Furthermore, the 74 L. pneumophila (sg1 = 13; sg3 = 13; sg4 = 3; sg7 = 38; sg10 = 5; sgX = 2) isolates were genotyped using the seven gene protocol sequence-based typing (SBT) scheme developed by the European Working Group for Legionella Infections (EWGLI). The results show that Legionella isolates were discriminated into nine distinct sequence typing (ST) profiles, five of which were new to the SBT database of EWGLI. Additionally, all of the ST1 serogroup 1 isolates were of the OLDA/Oxford subgroup. These baseline data will form the basis for the development of a Legionella environmental surveillance program and used for future epidemiological investigations.

  13. Legionella detection and subgrouping in water air-conditioning cooling tower systems in Kuwait.

    PubMed

    Al-Matawah, Qadreyah; Al-Zenki, Sameer; Al-Azmi, Ahmad; Al-Waalan, Tahani; Al-Salameen, Fadila; Hejji, Ahmad Ben

    2015-07-01

    The main aim of the study was to test for the presence of Legionnaires' disease-causing microorganisms in air-conditioned buildings in Kuwait using molecular technologies. For this purpose, 547 samples were collected from 38 cooling towers for the analysis of Legionella pneumophila. These samples included those from water (n = 178), air (n = 231), and swabs (n = 138). Out of the 547 samples, 226 (41%) samples were presumptive positive for L. pneumophila, with L. pneumophila viable counts in the positive water samples ranging from 1 to 88 CFU/ml. Of the Legionella culture-positive samples, 204 isolates were examined by latex agglutination. These isolates were predominately identified as L. pneumophila serogroup (sg) 2-14. Using the Dresden panel of monoclonal antibodies, 74 representatives isolates were further serogrouped. Results showed that 51% of the isolates belonged to serogroup 7 followed by 1 (18%) and 3 (18%). Serogroups 4 (4%) and 10 (7%) were isolated at a lower frequency, and two isolates could not be assigned to a serogroup. These results indicate the wide prevalence of L. pneumophila serogroup 7 as the predominant serogroup at the selected sampling sites. Furthermore, the 74 L. pneumophila (sg1 = 13; sg3 = 13; sg4 = 3; sg7 = 38; sg10 = 5; sgX = 2) isolates were genotyped using the seven gene protocol sequence-based typing (SBT) scheme developed by the European Working Group for Legionella Infections (EWGLI). The results show that Legionella isolates were discriminated into nine distinct sequence typing (ST) profiles, five of which were new to the SBT database of EWGLI. Additionally, all of the ST1 serogroup 1 isolates were of the OLDA/Oxford subgroup. These baseline data will form the basis for the development of a Legionella environmental surveillance program and used for future epidemiological investigations. PMID:25701245

  14. Tower of Hanoi Disk-Transfer Task: Influences of Strategy Knowledge and Learning on Performance

    ERIC Educational Resources Information Center

    Welsh, Marilyn C.; Huizinga, Mariette

    2005-01-01

    Tower of Hanoi has become a popular tool in cognitive and neuropsychology to assess a set of behaviors collectively referred to as executive functions. Substantial variability in performance on the Tower of Hanoi (TOH) disk-transfer task among normally functioning young adults, and potential contributions to these individual differences, were…

  15. Effectiveness of 1-bromo-3-chloro-5,5-dimethylhydantoin against Legionella pneumophila in a cooling tower

    SciTech Connect

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

    1984-06-01

    Cooling towers are considered to be man-made amplifiers of Legionella spp. Thus, the proper maintenance and choice of biocides is important. The only biocidal measure that has thus far been shown to be effective in field tests is the judicious use of chlorination. Perturbation studies with 1-bromo-3-chloro-5,5-dimethylhydantoin (Bromicide; Great Lakes Chemical Corporation, West Lafayette, Indiana) (BCD) were conducted on an industrial cooling tower shown to contain Legionella pneumophila. At the concentrations recommended by the manufacturer, neither the density nor the activity of L. pneumophila was affected. At concentrations greater than 2l0 ppm (2.0 ..mu..g/ml) free of residual, BCD was not effective in reducing L. pneumophila to source water concentrations, nor was it effective in reducing the 2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride activity of the bacterium in situ. The data indicate that at concentrations up to 2.0 ppm, BCD is not effective in these tower studies.

  16. Application of uncertainty analysis to cooling tower thermal performance tests

    SciTech Connect

    Yost, J.G.; Wheeler, D.E.

    1986-01-01

    The purpose of this paper is to provide an overview of uncertainty analyses. The following topics are addressed: l. A review and summary of the basic constituents of an uncertainty analysis with definitions and discussion of basic terms; 2. A discussion of the benefits and uses of uncertainty analysis; and 3. Example uncertainty analyses with emphasis on the problems, limitations, and site-specific complications.

  17. Analysis of mass transfer performance in an air stripping tower

    SciTech Connect

    Chung, T.W.; Lai, C.H.; Wu, H.

    1999-10-01

    The carryover of working solution in a traditional stripping tower is of serious concern in real applications. A U-shaped spray tower to prevent carryover has been designed to study the stripping of water vapor from aqueous desiccant solutions of 91.8 to 95.8 wt% triethylene glycol. In this study, water vapor was removed from the diluted desiccant solution by heating the solution and stripping it with the ambient air. Therefore, the solution was concentrated to a desired concentration. This spray tower was capable of handling air flow rates from 3.2 to 5.13 kg/min and liquid flow rates from 1.6 to 2.76 kg/min. Since the literature data on air stripping towers are limited, studies on the mass transfer coefficient and other mass transfer parameters were carried out in this study. Under the operating conditions, the overall mass transfer coefficient calculated from the experimental data varied from 0.053 to 0.169 mol/m{sup 3}{center{underscore}dot}s. These corresponded to heights of a transfer unit of 2.3 to 0.71 m, respectively. The rates of stripping in this spray tower were typically varied from 2.28 to 12.15 kg H{sub 2}O/h. A correlation of the mass transfer coefficient for the air stripping process was also developed in this study.

  18. Performance of cross-cooled desiccant dehumidifiers

    SciTech Connect

    Mei, V.C.; Lavan, Z.

    1980-01-01

    A cross-cooled silica gel desiccant dehumidifier model was designed, built and tested. The performance of the unit was studied as a function of inlet process stream dew point, process stream and cooling stream flowrates and regeneration stream temperature and dew point. The tests were also simulated by a computer program and were compared to the experimental results.

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

    PubMed

    Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

    2013-01-01

    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

  20. Acidity of vapor plume from cooling tower mixed with flue gases emitted from coal-fired power plant.

    PubMed

    Hlawiczka, Stanislaw; Korszun, Katarzyna; Fudala, Janina

    2016-06-01

    Acidity of products resulting from the reaction of flue gas components emitted from a coal-fired power plant with water contained in a vapor plume from a wet cooling tower was analyzed in a close vicinity of a power plant (710 m from the stack and 315 m from the cooling tower). Samples of this mixture were collected using a precipitation funnel where components of the mixed plumes were discharged from the atmosphere with the rainfall. To identify situations when the precipitation occurred at the same time as the wind directed the mixed vapor and flue gas plumes above the precipitation funnel, an ultrasound anemometer designed for 3D measurements of the wind field located near the funnel was used. Precipitation samples of extremely high acidity were identified - about 5% of samples collected during 12 months showed the acidity below pH=3 and the lowest recorded pH was 1.4. During the measurement period the value of pH characterizing the background acidity of the precipitation was about 6. The main outcome of this study was to demonstrate a very high, and so far completely underestimated, potential of occurrence of episodes of extremely acid depositions in the immediate vicinity of a coal-fired power plant. PMID:26950639

  1. Acidity of vapor plume from cooling tower mixed with flue gases emitted from coal-fired power plant.

    PubMed

    Hlawiczka, Stanislaw; Korszun, Katarzyna; Fudala, Janina

    2016-06-01

    Acidity of products resulting from the reaction of flue gas components emitted from a coal-fired power plant with water contained in a vapor plume from a wet cooling tower was analyzed in a close vicinity of a power plant (710 m from the stack and 315 m from the cooling tower). Samples of this mixture were collected using a precipitation funnel where components of the mixed plumes were discharged from the atmosphere with the rainfall. To identify situations when the precipitation occurred at the same time as the wind directed the mixed vapor and flue gas plumes above the precipitation funnel, an ultrasound anemometer designed for 3D measurements of the wind field located near the funnel was used. Precipitation samples of extremely high acidity were identified - about 5% of samples collected during 12 months showed the acidity below pH=3 and the lowest recorded pH was 1.4. During the measurement period the value of pH characterizing the background acidity of the precipitation was about 6. The main outcome of this study was to demonstrate a very high, and so far completely underestimated, potential of occurrence of episodes of extremely acid depositions in the immediate vicinity of a coal-fired power plant.

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

    PubMed

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

    2009-04-01

    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

  3. Differentiating Tower of Hanoi performance: interactive effects of psychopathic tendencies, impulsive response styles, and modality.

    PubMed

    Salnaitis, Christina L; Baker, Crystal A; Holland, James; Welsh, Marilyn

    2011-01-01

    Previous research has demonstrated that performance on the computerized Tower of Hanoi is lower than performance on the manual Tower of Hanoi. The present study was conducted to elucidate potential factors that contribute to performance differences across modalities. Personality characteristics related to psychopathy and impulsive response styles were hypothesized to be correlates of poor performance on the computerized version of the Tower of Hanoi, which is a problem-solving task that requires working memory, planning, and inhibition. Eighty-four college students from a mid-sized university participated. Participants were grouped as low, middle, or high psychopathy based on their total scores on the Psychopathic Personality Inventory. A 2 (Modality) × 3 (Psychopathy) analysis of covariance, controlling for visuospatial working memory, yielded a significant interaction, in which the high psychopathy group did not differ in performance across modality, whereas the low and middle psychopathy groups performed more poorly on the computerized version. Subsequent analyses on reaction time and accuracy for the computerized modality indicated that a reflective, methodical approach to the computerized task was more productively utilized in the low psychopathy group, whereas the fast and accurate approach was more productively utilized in the high psychopathy group. These results suggest that individuals with elevated psychopathic tendencies within a normal population are not necessarily deficient in problem-solving performance on the Tower of Hanoi. Impulsive responding is associated with poor performance in the computerized version of the Tower of Hanoi, irrespective of psychopathic tendencies. Caution should be exercised in interpreting scores on the computerized Tower of Hanoi because the psychometric properties required for comparability with the manual version have not been sufficiently demonstrated. PMID:21390899

  4. Quasi One-Dimensional Model of Natural Draft Wet-Cooling Tower Flow, Heat and Mass Transfer

    NASA Astrophysics Data System (ADS)

    Hyhlík, Tomáš

    2015-05-01

    The article deals with the development of CFD (Computational Fluid Dynamics) model of natural draft wet-cooling tower flow, heat and mass transfer. The moist air flow is described by the system of conservation laws along with additional equations. Moist air is assumed to be homogeneous mixture of dry air and water vapour. Liquid phase in the fill zone is described by the system of ordinary differential equations. Boundary value problem for the system of conservation laws is discretized in space using Kurganov-Tadmor central scheme and in time using strong stability preserving Runge-Kutta scheme. Initial value problems in the fill zone is solved by using standard fourth order Runge-Kutta scheme. The interaction between liquid water and moist air is done by source terms in governing equations.

  5. Mathematical Model of Two Phase Flow in Natural Draft Wet-Cooling Tower Including Flue Gas Injection

    NASA Astrophysics Data System (ADS)

    Hyhlík, Tomáš

    2016-03-01

    The previously developed model of natural draft wet-cooling tower flow, heat and mass transfer is extended to be able to take into account the flow of supersaturated moist air. The two phase flow model is based on void fraction of gas phase which is included in the governing equations. Homogeneous equilibrium model, where the two phases are well mixed and have the same velocity, is used. The effect of flue gas injection is included into the developed mathematical model by using source terms in governing equations and by using momentum flux coefficient and kinetic energy flux coefficient. Heat and mass transfer in the fill zone is described by the system of ordinary differential equations, where the mass transfer is represented by measured fill Merkel number and heat transfer is calculated using prescribed Lewis factor.

  6. Future Laser-Cooled Microwave Clock Performance

    NASA Technical Reports Server (NTRS)

    Gibble, Kurt

    1997-01-01

    Limitations to the performance of laser-cooled earth and space-based Cs clocks will be critically discussed. The most significant limitation to the stability and accuracy of laser-cooled atomic clocks is the frequency shift due to cold collisions. Because of it, laser-cooled Cs clocks must be operated at low density and this implies that space based Cs clock performance will not be significantly better than earth based. To regain some of the high accuracy and stability lost to the low density, clocks can be designed to multiply launch (or juggle) atoms. Clocks based on other atoms, in particular Rb-87 or possibly Rb-85, may have much smaller cold collision frequency shifts and therefore be capable of higher stability and accuracy, especially in a space environment.

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

    PubMed

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

    2014-04-01

    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.

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

    PubMed

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

    2014-04-01

    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

  9. Performance of the Integrated Tracker Towers of the GLAST Large Area Telescope

    SciTech Connect

    Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giglietto, N.; Giordano, F.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari

    2007-02-15

    The GLAST Large Area Telescope (LAT) is a high energy gamma ray observatory, mounted on a satellite that will be own in 2007. The LAT tracker consists of an array of tower modules, equipped with planes of silicon strip detectors (SSDs) interleaved with tungsten converter layers. Photon detection is based on the pair conversion process; silicon strip detectors will reconstruct tracks of electrons and positrons. The instrument is actually being assembled. The first towers have been already tested and integrated at Stanford Linear Accelerator Center (SLAC). An overview of the integration stages of the main components of the tracker and a description of the pre-launch tests will be given. Experimental results on the performance of the tracker towers will be also discussed.

  10. Performance of Retarded Adolescents and Nonretarded Children on the Tower of Hanoi Problem

    ERIC Educational Resources Information Center

    Byrnes, Mary Ann M.; Spitz, Herman H.

    1977-01-01

    The performance of 4 groups of mentally retarded Ss, ages 14-17 with mental ages of 8-11, was compared to that of 90 non retarded Ss, grades K-5 with comparable mental ages, on the solution of 2 and 3 disc Hanoi Tower puzzles, solutions to which require logical forsight. (BB)

  11. Performance of Mentally Retarded Adults on the Tower of Hanoi Problem.

    ERIC Educational Resources Information Center

    Waeber, Alexandre; Lambert, Jean-Luc

    1987-01-01

    The study examined cognitive strategies of 21 moderately and severely retarded adults in a simplified Tower of Hanoi problem. Modification of the basic problem by reducing the number of rules and presenting the goal configuration resulted in successful performance during the first training session by 13 subjects. (DB)

  12. Horizontal cooling towers: riverine ecosystem services and the fate of thermoelectric heat in the contemporary Northeast US

    NASA Astrophysics Data System (ADS)

    Stewart, Robert J.; Wollheim, Wilfred M.; Miara, Ariel; Vörösmarty, Charles J.; Fekete, Balazs; Lammers, Richard B.; Rosenzweig, Bernice

    2013-06-01

    The electricity sector is dependent on rivers to provide ecosystem services that help regulate excess heat, either through provision of water for evaporative cooling or by conveying, diluting and attenuating waste heat inputs. Reliance on these ecosystem services alters flow and temperature regimes, which impact fish habitat and other aquatic ecosystem services. We demonstrate the contemporary (2000-2010) dependence of the electricity sector on riverine ecosystem services and associated aquatic impacts in the Northeast US, a region with a high density of thermoelectric power plants. We quantify these dynamics using a spatially distributed hydrology and water temperature model (the framework for aquatic modeling in the Earth system), coupled with the thermoelectric power and thermal pollution model. We find that 28.4% of thermoelectric heat production is transferred to rivers, whereas 25.9% is directed to vertical cooling towers. Regionally, only 11.3% of heat transferred to rivers is dissipated to the atmosphere and the rest is delivered to coasts, in part due to the distribution of power plants within the river system. Impacts to the flow regime are minimal, while impacts to the thermal regime include increased river lengths of unsuitable habitats for fish with maximum thermal tolerances of 24.0, 29.0, and 34.0 ° C in segments downstream of plants by 0.6%, 9.8%, and 53.9%, respectively. Our analysis highlights the interactions among electricity production, cooling technologies, aquatic impacts, and ecosystem services, and can be used to assess the full costs and tradeoffs of electricity production at regional scales.

  13. Laboratory observations of biocide efficiency against Legionella in model cooling tower systems

    SciTech Connect

    Thomas, W.M.; Eccles, J.; Fricker, C.

    1999-07-01

    The efficacy of specific oxidizing and non-oxidizing biocides was examined using a model cooling system inoculated with a microcosm containing an environmental isolate of Legionella pneumophila. The microcosm was prepared in a two-stage chemostat, which provided a consistent source of microbiological inoculum for the study. The microcosm consisted of both sessile (within biofilms) and planktonic Legionella in association with other microorganisms, including Pseudomonas species and cyst-forming ameobae. A procedure was established to successfully transfer the chemostat grown inoculum to the model cooling system and establish both sessile and planktonic forms of Legionella in the model cooling system. The greatest biocidal effect for all of the biocides was observed immediately after dosing. This effect was relatively short-lived even for the slow acting biocides such isothiazolin (as 8 ppm active) where an effect was only observed over the first 12 hours. The faster acting biocides, DBNPA (as 8 ppm active) and gluteraldehyde (as 27 ppm active), did initially reduce Legionella populations but did not totally eliminate Legionella or provide lasting control. Chlorine and bromine (as 0.5--1.5 ppm free halogen), and ozone (as 0.1--0.5 ppm free reserve) reduced and controlled Legionella populations so long as a free reserve of oxidant was maintained. Legionella recovered quickly after biocide dosing, reestablishing similar levels to those observed before dosing.

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

    PubMed

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

    2010-12-01

    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.

  15. Corrosion-induced Whole Effluent Toxicity from a cooling tower: A toxicity reduction evaluation case study

    SciTech Connect

    Fort, D.J.; Stover, E.L.; Talley, J.M.; Copenhaver, M.B.

    1996-11-01

    As the result of Whole Effluent Toxicity (WET) test failures with Daphnia pulex, the US Environmental Protection Agency (EPA) required an industrial facility discharging approximately 5 million gallons per day (MGD) of recirculating cooling water obtained from a large freshwater river to conduct a Toxicity Reduction Evaluation (TRE) program. Under the terms of the National Pollutant Discharge Elimination System (NPDES) permit, the facility was required to conduct 48-hour acute toxicity tests with D. pulex and Pimephales promelas (fathead minnow). Although effluent toxicity to D. pulex was consistently observed, no toxicity was induced to the fathead minnow during the TRE program. The situation was further complicated by the fact that the recirculating cooling water was discharged back into the same river. The objectives of the TRE program were to investigate the causes of toxicity, locate potential sources of the suspected toxicant(s), and identify practicable toxicity reduction methodologies to be used. The TRE program approach and results from the associated studies are presented in this report, including a successful remedy for the WET problem.

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

    PubMed

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

    2010-12-01

    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

  17. Working Memory, Inhibition, and Fluid Intelligence as Predictors of Performance on Tower of Hanoi and London Tasks

    ERIC Educational Resources Information Center

    Zook, N.A.; Davalos, D.B.; DeLosh, E.L.; Davis, H.P.

    2004-01-01

    The contributions of working memory, inhibition, and fluid intelligence to performance on the Tower of Hanoi (TOH) and Tower of London (TOL) were examined in 85 undergraduate participants. All three factors accounted for significant variance on the TOH, but only fluid intelligence accounted for significant variance on the TOL. When the…

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

    NASA Astrophysics Data System (ADS)

    Tan, Kunxiong

    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

  19. [Three patients with pneumonia due to Legionella associated with a sauna, a cooling tower and a caravan in The Netherlands].

    PubMed

    Bencini, M A; IJzerman, E P F; Bruin, J P; den Boer, J W

    2005-09-01

    In three male patients with lower respiratory disease, aged 51, 32 and 63 years, Legionnaires' disease was diagnosed by urinary antigen test and culture of the respiratory-tract fluid. In the second patient, the bronchoalveolar fluid also contained Streptococcus pneumoniae and Haemophilus influenzae. All three patients recovered after treatment with azithromycin in the first, cefotaxime, vancomycin and levofloxacin in the second, and erythromycin and ciprofloxacin in the third, respectively. Legionella pneumophila pneumonia is clinically not clearly distinct from other pneumonias and has a high mortality rate when not treated with the proper antibiotics. For that reason, adequate and swift diagnosis is of great importance. The urinary antigen test meets both of these criteria. Still, it is advisable to use culture and serology as well if Legionnaires' disease is suspected in a patient, since the urinary antigen test has limitations. In addition, patient isolates are ofepidemiological importance for public health. By comparing available patient isolates with Legionella strains from water sources, it is possible to identify sources of infection. In 2002, based on this principle, a project was started in The Netherlands aimed at identifying sources of infection, thereby preventing outbreaks of Legionnaires' disease by swift elimination of the source. Since the start of the project, 29 sources have been identified. In the cases described above these were a sauna, a cooling tower and a caravan, respectively. In suspected cases, respiratory-tract fluid must be collected to make possible such a source investigation.

  20. Roseomonas tokyonensis sp. nov. isolated from a biofilm sample obtained from a cooling tower in Tokyo, Japan.

    PubMed

    Furuhata, Katsunori; Ishizaki, Naoto; Edagawa, Akiko; Fukuyama, Masafumi

    2013-01-01

    Strain K-20(T), a Gram-negative, nonmotile, nonspore-forming and strictly aerobic coccobacillus, which produces a pale pink pigment (R2A agar medium, 30℃, seven days) was isolated from a sample of biofilm obtained from a cooling tower in Tokyo, Japan. A phylogenetic analysis of the 16S rRNA partial gene sequences (1,439 bp) showed that the strain (accession number: AB297501) was related to Roseomonas frigidaquae CW67(T) and Roseomonas stagni HS-69(T) with 97.4% and 96.9% sequence similarity, respectively. Strain K-20(T) formed a distinct cluster with Roseomonas frigidaquae CW67(T) in the phylogenetic tree at a high bootstrap value (93%); however, distance was recognized between the strains. In addition, the DNA-DNA hybridization level between strain K-20(T) and Roseomonas frigidaquae JCM 15073(T) was 33%. The taxonomic data indicate that K-20(T) (=JCM 14634(T) =KCTC 32152(T)) should be classified in the genus Roseomonas as the type strain of a novel species, Roseomonas tokyonensis sp. nov.

  1. Roseomonas tokyonensis sp. nov. isolated from a biofilm sample obtained from a cooling tower in Tokyo, Japan.

    PubMed

    Furuhata, Katsunori; Ishizaki, Naoto; Edagawa, Akiko; Fukuyama, Masafumi

    2013-01-01

    Strain K-20(T), a Gram-negative, nonmotile, nonspore-forming and strictly aerobic coccobacillus, which produces a pale pink pigment (R2A agar medium, 30℃, seven days) was isolated from a sample of biofilm obtained from a cooling tower in Tokyo, Japan. A phylogenetic analysis of the 16S rRNA partial gene sequences (1,439 bp) showed that the strain (accession number: AB297501) was related to Roseomonas frigidaquae CW67(T) and Roseomonas stagni HS-69(T) with 97.4% and 96.9% sequence similarity, respectively. Strain K-20(T) formed a distinct cluster with Roseomonas frigidaquae CW67(T) in the phylogenetic tree at a high bootstrap value (93%); however, distance was recognized between the strains. In addition, the DNA-DNA hybridization level between strain K-20(T) and Roseomonas frigidaquae JCM 15073(T) was 33%. The taxonomic data indicate that K-20(T) (=JCM 14634(T) =KCTC 32152(T)) should be classified in the genus Roseomonas as the type strain of a novel species, Roseomonas tokyonensis sp. nov. PMID:24366626

  2. Evaporation Tower With Prill Nozzles

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1984-01-01

    Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

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

    PubMed

    Haslan, Ezgi; Kimiran-Erdem, Ayten

    2013-09-01

    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 < 0.05). In addition, it was found that bacteria belonging to the same species isolated from 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

  4. Intermittent Palm Cooling's Impact on Resistive Exercise Performance.

    PubMed

    Caruso, J F; Barbosa, A; Erickson, L; Edwards, R; Perry, R; Learmonth, L; Potter, W T

    2015-10-01

    To examine palm cooling's (15 °C) impact, subjects performed 3 four-set leg press workouts in a randomized sequence. Per workout they received 1 of 3 treatments: no palm cooling, palm cooling between sets, or palm cooling between sets and post-exercise. Dependent variables were examined with three-way ANOVAs; average power underwent a three-way ANCOVA with body fat percentage as the covariate. Simple effects analysis was our post hoc and α=0.05. Left hand skin temperatures produced a two-way interaction (no palm cooling, palm cooling between sets>palm cooling between sets and post-exercise at several time points). A "high responder" subset had their data analyzed with an additional three-way ANOVA that again produced a two-way interaction (palm cooling between sets>no palm cooling>palm cooling between sets and post-exercise at multiple time points). Blood lactate results included a two-way interaction (no palm cooling>palm cooling between sets, palm cooling between sets and post-exercise at 0 min post-exercise). Average power yielded a two-way interaction (palm cooling between sets, palm cooling between sets>no palm cooling for the fourth set). Intermittent palm cooling hastened heat removal and blood lactate clearance, as well as delayed average power decrements. PMID:26038879

  5. Coolerado 5 Ton RTU Performance: Western Cooling Challenge Results (Revised)

    SciTech Connect

    Kozubal, E.; Slayzak, S.

    2010-11-01

    The Western Cooling Efficiency Center (WCEC) developed a set of criteria for test conditions, minimum energy, and water use performance for prototype cooling equipment and identified these conditions as indicative of western state climates.

  6. Lawrence Livermore National Laboratory (LLNL) Experimental Test Site (Site 300) Salinity Evaluation and Minimization Plan for Cooling Towers and Mechanical Equipment Discharges

    SciTech Connect

    Daily III, W D

    2010-02-24

    This document was created to comply with the Central Valley Regional Water Quality Control Board (CVRWQCB) Waste Discharge Requirement (Order No. 98-148). This order established new requirements to assess the effect of and effort required to reduce salts in process water discharged to the subsurface. This includes the review of technical, operational, and management options available to reduce total dissolved solids (TDS) concentrations in cooling tower and mechanical equipment water discharges at Lawrence Livermore National Laboratory's (LLNL's) Experimental Test Site (Site 300) facility. It was observed that for the six cooling towers currently in operation, the total volume of groundwater used as make up water is about 27 gallons per minute and the discharge to the subsurface via percolation pits is 13 gallons per minute. The extracted groundwater has a TDS concentration of 700 mg/L. The cooling tower discharge concentrations range from 700 to 1,400 mg/L. There is also a small volume of mechanical equipment effluent being discharged to percolation pits, with a TDS range from 400 to 3,300 mg/L. The cooling towers and mechanical equipment are maintained and operated in a satisfactory manner. No major leaks were identified. Currently, there are no re-use options being employed. Several approaches known to reduce the blow down flow rate and/or TDS concentration being discharged to the percolation pits and septic systems were reviewed for technical feasibility and cost efficiency. These options range from efforts as simple as eliminating leaks to implementing advanced and innovative treatment methods. The various options considered, and their anticipated effect on water consumption, discharge volumes, and reduced concentrations are listed and compared in this report. Based on the assessment, it was recommended that there is enough variability in equipment usage, chemistry, flow rate, and discharge configurations that each discharge location at Site 300 should be

  7. Thermotechnical performance of an air-cooled tuyere with air cooling channels in series

    NASA Astrophysics Data System (ADS)

    Shen, Yuansheng; Zhou, Yuanyuan; Zhu, Tao; Duan, Guangbin

    2016-03-01

    To reduce the cooling air consumption for an air-cooled tuyere, an air-cooled tuyere with air cooling channels in series is developed based on several hypotheses, i.e., a transparent medium in the blast furnace, among others, and the related mathematical models are introduced and developed. Referring to the data from a BF site, the thermotechnical computation for the air-cooled tuyere was performed, and the results show that when the temperature of the inlet cooling air increases, the temperatures for the outlet cooling air, the outer surface of the tuyere, the walls of the air cooling channels and the center channel as well as the heat going into the center channel increase, but the heat absorbed by the cooling air flowing through the air cooling channels decreases. When the cooling air flow rate under the standard state increases, the physical parameters mentioned above change in an opposite directions. Compared to a water-cooled tuyere, the energy savings for an air-cooled tuyere are more than 0.23 kg/min standard coal.

  8. Cooling performance of solar cell-driven, thermoelectric cooling prototype headgear

    SciTech Connect

    Hara, T.; Obora, H.; Sato, S.

    1998-07-01

    Cooling performance of solar cell driven, thermoelectric cooling prototype headgear was examined experimentally. Three types of prototype headgear were made and examined. They were cooled by thermoelectric elements and driven by solar cells. The authors are always able to be cooled anytime and anywhere inside the house in hot season. However, they were not able to be cooled when they worked outside the house. Especially, a personal air-conditioning system is required for the people working outside. Some cooling caps with an electric fan driven by solar cells can be often seen now. However, the fan only blows hot air to the face. They cannot cool down the face below the ambient temperature. The authors tried to cool down the face to the lower temperature below the ambient by a refrigeration system. A thermoelectric element was set at the front of a headgear such as baseball cap or straw hat to cool a forehead. Some pieces of solar cells were mounted on the top and the brim of the headgear to work the thermoelectric element. Hot side of thermoelectric element was cooled by a plate fin an electric fan. The electric fan was also driven by a solar cell. Two types of baseball caps with solar cells and a thermoelectric element and a type of straw hat with them were made and tested. Solar cells were connected to optimize the electric power for the thermoelectric element. An electric fan and its power input were selected to cool maximum the thermoelectric element. Cooling performance and thermal comfort of the headgear were examined by testers in case of sitting, walking and bicycling. The temperature difference between ambient and cooling temperature was required only about 4 degree Celsius. Required power by solar cells was up to about 1.5 watt for a personal cooling.

  9. Performance Analysis of XCPC Powered Solar Cooling Demonstration Project

    NASA Astrophysics Data System (ADS)

    Widyolar, Bennett K.

    A solar thermal cooling system using novel non-tracking External Compound Parabolic Concentrators (XCPC) has been built at the University of California, Merced and operated for two cooling seasons. Its performance in providing power for space cooling has been analyzed. This solar cooling system is comprised of 53.3 m2 of XCPC trough collectors which are used to power a 23 kW double effect (LiBr) absorption chiller. This is the first system that combines both XCPC and absorption chilling technologies. Performance of the system was measured in both sunny and cloudy conditions, with both clean and dirty collectors. It was found that these collectors are well suited at providing thermal power to drive absorption cooling systems and that both the coinciding of available thermal power with cooling demand and the simplicity of the XCPC collectors compared to other solar thermal collectors makes them a highly attractive candidate for cooling projects.

  10. Effect of cooling water impurities on deposit control polymer performance

    SciTech Connect

    Amjad, Z.; Zuhl, R.W.; Zibrida, J.F.

    2000-05-01

    The performance of polymeric inhibitors in treating recirculating cooling water systems is influenced by many factors, including pH, temperature, makeup water quality, and heat exchanger metallurgy. Impurities such as metal ions and suspended matter impact the performance of polymeric inhibitors used in phosphate-based treatment cooling water programs.

  11. Hydronic radiant cooling: Overview and preliminary performance assessment

    SciTech Connect

    Feustel, H.E.

    1993-05-01

    A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distribution systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system's development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.

  12. Epidemiological investigation and case-control study: a Legionnaires' disease outbreak associated with cooling towers in Warstein, Germany, August-September 2013.

    PubMed

    Maisa, Anna; Brockmann, Ansgar; Renken, Frank; Lück, Christian; Pleischl, Stefan; Exner, Martin; Daniels-Haardt, Inka; Jurke, Annette

    2015-01-01

    Between 1 August and 6 September 2013, an outbreak of Legionnaires' disease (LD) with 159 suspected cases occurred in Warstein, North Rhine-Westphalia, Germany. The outbreak consisted of 78 laboratory-confirmed cases of LD, including one fatality, with a case fatality rate of 1%. Legionella pneumophila, serogroup 1, subtype Knoxville, sequence type 345, was identified as the epidemic strain. A case-control study was conducted to identify possible sources of infection. In univariable analysis, cases were almost five times more likely to smoke than controls (odds ratio (OR): 4.81; 95% confidence interval (CI): 2.33-9.93; p < 0.0001). Furthermore, cases were twice as likely to live within a 3 km distance from one identified infection source as controls (OR: 2.14; 95% CI: 1.09-4.20; p < 0.027). This is the largest outbreak of LD in Germany to date. Due to a series of uncommon events, this outbreak was most likely caused by multiple sources involving industrial cooling towers. Quick epidemiological assessment, source tracing and shutting down of potential sources as well as rapid laboratory testing and early treatment are necessary to reduce morbidity and mortality. Maintenance of cooling towers must be carried out according to specification to prevent similar LD outbreaks in the future. PMID:26607018

  13. Utility-Scale Power Tower Solar Systems: Performance Acceptance Test Guidelines

    SciTech Connect

    Kearney, D.

    2013-03-01

    The purpose of these Guidelines is to provide direction for conducting performance acceptance testing for large power tower solar systems that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. The recommendations have been developed under a National Renewable Energy Laboratory (NREL) subcontract and reviewed by stakeholders representing concerned organizations and interests throughout the concentrating solar power (CSP) community. An earlier NREL report provided similar guidelines for parabolic trough systems. These Guidelines recommend certain methods, instrumentation, equipment operating requirements, and calculation methods. When tests are run in accordance with these Guidelines, we expect that the test results will yield a valid indication of the actual performance of the tested equipment. But these are only recommendations--to be carefully considered by the contractual parties involved in the Acceptance Tests--and we expect that modifications may be required to fit the particular characteristics of a specific project.

  14. A Comparison of Performance on the Towers of London and Hanoi in Young Children

    ERIC Educational Resources Information Center

    Bull, Rebecca; Espy, Kimberly Andrews; Senn, Theresa E.

    2004-01-01

    Background: The Towers of London (TOL) and Hanoi (TOH) have been viewed as equivalent measures of planning and/or problem solving, although recent evidence in adults suggests that the underlying measurement characteristics of these two tasks may differ. As tower tasks are one of the few instruments that can be used to assess executive functioning…

  15. Modeling of the Evaporative Cooling of Running-Down Liquid Films in the Slit Channel of the Spraying Device of a Cooling Tower

    NASA Astrophysics Data System (ADS)

    Dashkov, G. V.; Malenko, G. L.; Solodukhin, A. D.; Tyutyuma, V. D.

    2014-11-01

    This paper presents the results of computational modeling of the nonstationary evaporative cooling of a liquid film running down a vertical surface cooled by a turbulent vapor-air counterflow. The heat and mass transfer problem has been formulated in conjugate form. The calculation data on the total heat flow density at the interface for various instants of time are given.

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

    PubMed

    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

    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

  17. Performance of the Towers of Hanoi task and cortical electroencephalographic power changes associated with infancy, adolescence, and early adulthood.

    PubMed

    Guevara, Miguel Ángel; Hernández González, Marisela; Rizo Martínez, Lucía Ester; Robles Aguirre, Francisco Abelardo

    2013-11-01

    The executive functions, which depend on the adequate maturation and functioning of the prefrontal cortex and its connection to posterior zones, follow a process of development as age increases. This work studied changes in the absolute power (AP) of EEG activity recorded in the prefrontal and parietal areas during the performance of the Tower of Hanoi task in children, adolescents, and young adults. Three groups of healthy male subjects such as G1, 11-13; G2, 18-20; and G3, 26-30, years of age were recorded at the F3, F4, P3, and P4 derivations under two conditions: basal and performance of the Towers of Hanoi task. The majority of subjects in G1 failed to complete the task in the allotted time (7 min), while those in G2 and G3 were able to resolve the task quickly and efficiently. During the Towers of Hanoi task, G1 showed an increase of AP in the delta band only in the frontal areas, with a decrease in the alpha1 and alpha2 sub-bands only at the parietal derivations, while G2 and G3 were characterized by an increase of AP in the delta band and a decreased AP in the alpha1 and alpha2 sub-bands in all derivations. These data demonstrate that during the performance of the Towers of Hanoi task, the prefrontal and parietal areas show a characteristic EEG pattern in relation to age. It is probable that the AP patterns obtained in G2 and G3 are associated with the functional changes at cortical levels that adolescents and early adults require to achieve an adequate and fast performance of the Towers of Hanoi task. PMID:24013790

  18. Ozone treatment of cooling water, results of a full-scale performance evaluation

    SciTech Connect

    Coppenger, D.G.; Crocker, B.R.; Wheeler, D.E.

    1989-01-01

    This paper is the first technical status report of a continuing evaluation of ozone treatment for cooling tower water. Data will be presented that illustrate the results of ozone treatment in a 3400-ton air-conditioning cooling system at the Oak Ridge Y-12 Plant. Heat-transfer data and equipment inspections confirm that a threshold surface temperature exists, below which heat-exchange surfaces remain free of mineral scale. Heat-exchange surfaces that exceed the temperature threshold experience calcium carbonate scaling. The temperature threshold effect may explain why ozone treatment has been reported as a successful treatment for air-conditioning cooling towers but has not been successful in higher temperature process cooling systems. Plans for future ozone investigations will be discussed. 15 refs., 6 figs., 6 tabs.

  19. PERFORMANCE EVALUATION OF CEILING RADIANT COOLING SYSTEM IN COMPOSITE CLIMATE

    SciTech Connect

    Sharma, Anuj; Mathur, Jyotirmay; Bhandari, Mahabir S

    2015-01-01

    Radiant cooling systems are proving to be an energy efficient solution due to higher thermal capacity of cooling fluid especially for the buildings that require individual zone controls and where the latent loads are moderate. The Conventional air conditioners work at very low temperature i.e.5-8 c (refrigerant evaporator inlet) while the radiant cooling systems, also referred as high temperature cooling system, work at high temperatures i.e. 14-18 c. The radiant cooling systems can maintain lower MRT (Mean Radiant Temperature) as ceiling panels maintain uniform temperature gradient inside room and provide higher human comfort. The radiant cooling systems are relatively new systems and their operation and energy savings potential are not quantified for a large number of buildings and operational parameters. Moreover, there are only limited numbers of whole building simulation studies have been carried out for these systems to have a full confidence in the capability of modelling tools to simulate these systems and predict the impact of various operating parameters. Theoretically, savings achieve due to higher temperature set point of chilled water, which reduces chiller-running time. However, conventional air conditioner runs continuously to maintain requisite temperature. In this paper, experimental study for performance evaluation of radiant cooling system carried out on system installed at Malaviya National Institute of Technology Jaipur. This paper quantifies the energy savings opportunities and effective temperature by radiant cooling system at different chilled water flow rates and temperature range. The data collected/ analysed through experimental study will used for calibration and validation of system model of building prepared in building performance simulation software. This validated model used for exploring optimized combinations of key parameters for composite climate. These optimized combinations will used in formulation of radiant cooling system

  20. Hydronic radiant cooling: Overview and preliminary performance assessment

    SciTech Connect

    Feustel, H.E.

    1993-05-01

    A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distribution systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system`s development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.

  1. Phase space density as a measure of cooling performance for the international muon ionization cooling experiment

    SciTech Connect

    Berg, J. S.

    2015-05-03

    The International Muon Ionization Cooling Experiment (MICE) is an experiment to demonstrate ionization cooling of a muon beam in a beamline that shares characteristics with one that might be used for a muon collider or neutrino factory. I describe a way to quantify cooling performance by examining the phase space density of muons, and determining how much that density increases. This contrasts with the more common methods that rely on the covariance matrix and compute emittances from that. I discuss why a direct measure of phase space density might be preferable to a covariance matrix method. I apply this technique to an early proposal for the MICE final step beamline. I discuss how matching impacts the measured performance.

  2. Cryogenic performance of a cryocooler-cooled superconducting undulator

    NASA Astrophysics Data System (ADS)

    Fuerst, J. D.; Doose, C.; Hasse, Q.; Ivanyushenkov, Y.; Kasa, M.; Shiroyanagi, Y.

    2014-01-01

    A cryocooler-cooled superconducting undulator has been installed and operated with beam at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The device consists of a dual-core 42-pole magnet structure that is cooled to 4.2 K with a system of four cryocoolers operating in a zero-boil-off configuration. This effort represents the culmination of a development program to establish concept feasibility and evaluate cryostat design and cryocooler-based refrigeration. Cryostat performance is described including cool-down/warm-up, steady-state operation, cooling margin, and the impact of beam during operation in the APS storage ring. Plans for future devices with longer magnets, which will incorporate lessons learned from the development program, are also discussed.

  3. Cryogenic performance of a cryocooler-cooled superconducting undulator

    SciTech Connect

    Fuerst, J. D.; Doose, C.; Hasse, Q.; Ivanyushenkov, Y.; Kasa, M.; Shiroyanagi, Y.

    2014-01-29

    A cryocooler-cooled superconducting undulator has been installed and operated with beam at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The device consists of a dual-core 42-pole magnet structure that is cooled to 4.2 K with a system of four cryocoolers operating in a zero-boil-off configuration. This effort represents the culmination of a development program to establish concept feasibility and evaluate cryostat design and cryocooler-based refrigeration. Cryostat performance is described including cool-down/warm-up, steady-state operation, cooling margin, and the impact of beam during operation in the APS storage ring. Plans for future devices with longer magnets, which will incorporate lessons learned from the development program, are also discussed.

  4. Effect of weak swirling flow on film cooling performance

    NASA Astrophysics Data System (ADS)

    Gau, C.; Hwang, W. B.

    1990-10-01

    Experiments have been performed in a large circular pipe to study and obtain the film cooling effectivenesses with the presence of weak swirling flow in the mainstream. The swirling flow is generated by a flat vane swirler situated upstream. Cooling film is injected from an annular slot formed by the pipe wall and the circular cover plate. The radial temperature distribution measurements at several axial locations were used to infer the rate of mixing of film jet with swirling flow. The swirl number, which increases with turbulence intensity and swirl velocity in the mainstream, can significantly increase the mixing rate of film jet with swirl flow and decrease the film cooling effectiveness. During the course of the experiments, the blowing ratio ranged from 0.5 to 1.75 and the swirl number ranged from 0 to 0.6. Correlation equations for the film cooling effectiveness, which account for the effect of swirling flow, are obtained.

  5. Convection towers

    DOEpatents

    Prueitt, Melvin L.

    1996-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  6. Convection towers

    DOEpatents

    Prueitt, Melvin L.

    1995-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  7. Convection towers

    DOEpatents

    Prueitt, M.L.

    1996-01-16

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

  8. Convection towers

    DOEpatents

    Prueitt, Melvin L.

    1994-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

  9. CSP parabolic trough and power tower performance analysis through the Southern African universities radiometric network (SAURAN) data

    NASA Astrophysics Data System (ADS)

    Pidaparthi, A. S.; Dall, E. P.; Hoffmann, J. E.; Dinter, F.

    2016-05-01

    The objective of this paper is to analyse the performance of parabolic trough and power tower technologies by selecting two radiometric stations in different geographic locations, with approximately equal annual direct normal irradiance (DNI) values, but with different monthly DNI distributions. The two stations chosen for this study are situated at the University of Free State, Bloemfontein, Free State Province and in Vanrhynsdorp, Western Cape Province. The annual measured DNI values for both these locations in South Africa are in the range of 2500-2700 kWh/m2. The comparison between the different monthly DNI distributions of these selected sites includes an assessment of annual hourly data in order to study the performance analysis of the most mature concentrating solar power (CSP) technologies, namely parabolic trough and power tower plants. The weather data has been obtained from the Southern African Universities Radiometric Network (SAURAN). A comparison between the different monthly DNI distributions of these selected sites includes the assessment of hourly data. Selection of these radiometric stations has also been done on the basis that they have been operational for at least one year. The first year that most SAURAN stations have been online for at least one year is 2014, thus data from this year has been considered. The annual performance analysis shows that parabolic trough plants have a higher energy yield in Vanrhynsdorp while power tower plants seem to be more suitable for Bloemfontein. Power tower plants in both the locations have a higher annual energy yield when compared with parabolic trough plants. A parabolic trough power plant in Vanrhynsdorp in the Western Cape Province has very low monthly electricity generation in the winter months of May, June, July and August. This is partly due to the higher cosine losses in the parabolic trough `one-axis' tracking systems and lower DNI values in the winter months. However, a power tower plant in

  10. Current cost and performance requirements for residential cool storage systems

    SciTech Connect

    Brown, D.R.; Spanner, G.E.

    1988-08-01

    This study defines the current cost and performance requirements for residential cool storage technologies based on the characteristics of conventional air conditioning equipment and residential time-of-day (TOD) rate structures existing during the 1986--1987 time frame. Currently, rate structures are changing rapidly. Given the volatility of rate structures, the establishment of cost goal is challenging. The goals presented in this study are based on the utility rate structure as of 1986. This study serves to define residential cool storage cost and performance requirements in the current economic environment as well as the many issues affecting the requirements for residential cool storage systems both now and in the future. The same methodology can be employed to establish long-run goals once future rate structures are adequately defined. 12 refs., 6 figs., 18 tabs.

  11. The Physics of Shot Towers

    NASA Astrophysics Data System (ADS)

    Lipscombe, Trevor C.; Mungan, Carl E.

    2012-04-01

    In the late 18th and throughout the 19th century, lead shot for muskets was prepared by use of a shot tower. Molten lead was poured from the top of a tower and, during its fall, the drops became spherical under the action of surface tension. In this article, we ask and answer the question: How does the size of the lead shot depend on the height of the tower? In the process, we explain the basic technology underlying an important historical invention (the shot tower) and use simple physics (Newtonian mechanics and the thermodynamic laws of cooling) to model its operation.

  12. Ant Tower

    NASA Astrophysics Data System (ADS)

    Mlot, Nathan; Shinotsuka, Sho; Hu, David

    2010-11-01

    Ants walk via adhesive drops of fluid extruded by their feet. They also use these drops as mortar to build structures such as rafts, bridges and towers, each composed of thousands of ants linked together. We investigate experimentally the construction of triangular ant towers braced by hydrophobic walls. Particular attention is paid to the relationship between tower height and contact angle hysteresis of the wall. We rationalize tower height according to ant adhesion, and tower shape according to the constraints on a column of constant strength.

  13. Performance and upgrades of the Fermilab Accumulator stacktail stochastic cooling

    SciTech Connect

    Derwent, P.F.; Cullerton, Ed; McGinnis, David; Pasquinelli, Ralph; Sun, Ding; Tinsley, David; /Fermilab

    2005-11-01

    We report on the performance and planned upgrades to the Fermilab Accumulator Stacktail Stochastic Cooling System. The current system has achieved a maximum flux of 16.5e10/hour, limited by the input flux of antiprotons. The upgrades are designed to handle flux in excess of 40e10/hour.

  14. Performance of stabilized halogen biocides in cooling water

    SciTech Connect

    Dallmier, A.W.; Martens, J.D.; McCoy, W.F.

    1997-12-01

    Halogen-based biocides have been used for many years in cooling water to control microbial fouling. Potential problems associated with the misapplication of halogen-based biocides in cooling water are increased corrosion, degradation of scale and corrosion inhibitors, and poor storage stability. Advances and innovations in this field have led to products in which the oxidizing effects and degradative properties of the halogen are stabilized. This provides much more effective control of the microbial fouling process in cooling water shile being less aggressive towards other system components. Methods used to measure increased effectiveness of stabilized halogen biocides are presented and discussed in this paper. Laboratory and field experiments of a stabilized halogen antimicrobial control program are detailed. Performance of this stabilized halogen program for Legionella pneumophila control is also discussed.

  15. 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.

    PubMed

    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

    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

  16. Windmill tower

    SciTech Connect

    Schachle, C.; Schachle, E.C.; Schachle, J.R.; Schachle, P.J.

    1982-04-06

    A windmill tower supports a propeller and a platform that in turn supports a propeller feather control system and a generator system. The entire tower rotates at its base under changes in wind direction so the rotating propeller is constantly maintained upwind of the tower. The tower is a rigid structure that withstands cyclic thrust and torque loading sufficiently to reduce resonant vibrations of the tower as the propeller rotates under the influence of the wind. The resonant frequency of the tower can be higher than the passing frequency of the rotating propeller blades. The tower includes a pair of generally upright fore legs that converge upwardly toward a first apex on the propeller axis of rotation near the front of the platform immediately behind the propeller hub. A diagonal bracing strut extends downwardly from the first apex away from the plane of the fore legs and toward the rear of the tower. The bottoms of the fore legs and the diagonal bracing strut are rigidly interconnected by base plane truss members. A pair of upwardly converging aft legs extend diagonally upwardly from the bottoms of the fore legs toward a second apex aft of the first apex at the rear of the platform. At regular vertical intervals, stiffening trusses add rigidity to the main upright members of the tower structure. The natural frequency of the tower is raised by the fore legs and the diagonal bracing strut being interconnected in a rigid base plane truss. The diagonal bracing strut resists thrust loading on the tower, and the fore legs and aft legs resist torsional forces produced at the top of the tower.

  17. Convection towers

    DOEpatents

    Prueitt, M.L.

    1994-02-08

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

  18. Simulation and Evaluation of Small Scale Solar Power Tower Performance under Malaysia Weather Conditions

    NASA Astrophysics Data System (ADS)

    Gamil, A. M.; Gilani, S. I.; Al-Kayiem, H. H.

    2013-06-01

    Solar energy is the most available, clean, and inexpensive source of energy among the other renewable sources of energy. Malaysia is an encouraging location for the development of solar energy systems due to abundant sunshine (10 hours daily with average solar energy received between 1400 and 1900 kWh/m2). In this paper the design of heliostat field of 3 dual-axis heliostat units located in Ipoh, Malaysia is introduced. A mathematical model was developed to estimate the sun position and calculate the cosine losses in the field. The study includes calculating the incident solar power to a fixed target on the tower by analysing the tower height and ground distance between the heliostat and the tower base. The cosine efficiency was found for each heliostat according to the sun movement. TRNSYS software was used to simulate the cosine efficiencies and field hourly incident solar power input to the fixed target. The results show the heliostat field parameters and the total incident solar input to the receiver.

  19. Thermal Performance Testing of EMU and CSAFE Liquid Cooling Gannents

    NASA Technical Reports Server (NTRS)

    Rhodes, Richard; Bue, Grant; Meginnis, Ian; Hakam, Mary; Radford, Tamara

    2013-01-01

    Future exploration missions require the development of a new liquid cooling garment (LCG) to support the next generation extravehicular activity (EVA) suit system. The new LCG must offer greater system reliability, optimal thermal performance as required by mission directive, and meet other design requirements including improved tactile comfort. To advance the development of a future LCG, a thermal performance test was conducted to evaluate: (1) the comparable thermal performance of the EMU LCG and the CSAFE developed engineering evaluation unit (EEU) LCG, (2) the effect of the thermal comfort undergarment (TCU) on the EMU LCG tactile and thermal comfort, and (3) the performance of a torso or upper body only LCG shirt to evaluate a proposed auxiliary loop. To evaluate the thermal performance of each configuration, a metabolic test was conducted using the Demonstrator Spacesuit to create a relevant test environment. Three (3) male test subjects of similar height and weight walked on a treadmill at various speeds to produce three different metabolic loads - resting (300-600 BTU/hr), walking at a slow pace (1200 BTU/hr), and walking at a brisk pace (2200 BTU/hr). Each subject participated in five tests - two wearing the CSAFE full LCG, one wearing the EMU LCG without TCUs, one wearing the EMU LCG with TCUs, and one with the CSAFE shirt-only. During the test, performance data for the breathing air and cooling water systems and subject specific data was collected to define the thermal performance of the configurations. The test results show that the CSAFE EEU LCG and EMU LCG with TCU had comparable performance. The testing also showed that an auxiliary loop LCG, sized similarly to the shirt-only configuration, should provide adequate cooling for contingency scenarios. Finally, the testing showed that the TCU did not significantly hinder LCG heat transfer, and may prove to be acceptable for future suit use with additional analysis and testing.

  20. The influence of curvature on film cooling performance

    NASA Astrophysics Data System (ADS)

    Schwarz, S. G.; Goldstein, R. J.; Eckert, E. R. G.

    1990-06-01

    The effects of injection rate and strength of curvature on film cooling performance of gas injected through a row of holes on a convex surface is studied. Comparisons are made to film cooling of concave and flat surfaces. Three different relative strengths of curvature (ratio of radius of curvature to radius of injection hole), two density ratios (0.95 and 2.0), and a wide range of blowing rates (0.3 to 2.7) are considered. A foreign gas injection technique (mass transfer analogy) is used. The strength of curvature was controlled by varying the injection hole diameter. At low blowing rates, film cooling is more effective on the convex surface than on a flat or a concave surface. The cross stream pressure gradient present in curved flows tends to push the jet into the convex wall. As the injection rate is increased, normal and tangential jet momentum promote lift-off from the convex surface, thereby lowering performance. In contrast, previous studies show that a concave surface, tangential jet momentum, flow instabilities, and blockage improve performance on a concave surface as blowing rate is increased.

  1. Prefrontal-parietal correlation during performance of the towers of Hanoi task in male children, adolescents and young adults.

    PubMed

    Guevara, Miguel Angel; Rizo Martínez, Lucía Ester; Robles Aguirre, Francisco Abelardo; Hernández González, Marisela

    2012-01-01

    Potential age differences in the electroencephalographic (EEG) correlation (r) between the prefrontal and parietal cortices during performance of the Tower of Hanoi task were studied. In three groups of healthy males (G1, 11-13; G2, 18-20, and G3, 26-30, years of age) EEGs were recorded at baseline and during performance of the Tower of Hanoi task. The parameters of the task showed no significant differences among groups, though the majority of younger subjects failed to complete it. The G1 group showed increases only in the interparietal r. The G2 group showed an increased interhemispheric and intrahemispheric r in almost all frequency bands, while the r in G3 increased only in selected frequency bands in the right hemisphere. These findings demonstrate that the functional coupling between these two cortices shows a characteristic pattern during performance of the Hanoi task that, while specific to each age group, was not associated with the successful performance of the task. PMID:22682734

  2. Development of a new seminested PCR method for detection of Legionella species and its application to surveillance of legionellae in hospital cooling tower water.

    PubMed Central

    Miyamoto, H; Yamamoto, H; Arima, K; Fujii, J; Maruta, K; Izu, K; Shiomori, T; Yoshida, S

    1997-01-01

    The presence of PCR inhibitors in water samples is well known and contributes to the fact that a practical PCR assay has not been developed for legionella surveillance. In this study, we devised a new seminested PCR assay for detection of Legionella spp. in water samples as a means of overriding the PCR inhibitors without loss of sensitivity. The seminested PCR assay utilized primers to amplify the 16S rRNA gene (LEG primers) of 39 Legionella spp. The assay was specific to legionellae, and the sensitivity was 1 fg of extracted Legionella DNA in laboratory examination. To evaluate the feasibility and sensitivity of the PCR assay in identifying the presence of legionellae, it was used to survey Legionella contamination in the water of 49 cooling towers of 32 hospitals. A commercially available EnviroAmp Legionella kit and a culture method were also used in the survey for comparison with the seminested PCR assay. The detection rates of legionellae in the samples were 91.8% (45 of 49) by the PCR assay and 79.5% (39 of 49) by the culture method. The EnviroAmp kit revealed that 30.6% of the water samples (15 of 49) contained inhibitors of the PCR amplification. However, the seminested PCR assay could produce the Legionella-specific DNA bands in 14 of the 15 samples. Although 8 of the 14 samples were positive in the first-step PCR, 6 of the 14 samples became positive in the second-step PCR. These results suggest that the effect of PCR inhibitors in samples, if any, can be reduced because of the dilution of the sample in the second-step PCR and that sensitivity of detection can be increased by the second-step PCR. Thus, the seminested PCR assay with LEG primers to amplify the 16S rRNA gene of 39 Legionella spp. was a practical and sensitive method to detect Legionella spp. in water samples. PMID:9212400

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

    PubMed

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

    2015-05-01

    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.

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

    PubMed

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

    2015-05-01

    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

  5. Effects of nature of cooling surface on radiator performance

    NASA Technical Reports Server (NTRS)

    Parsons, S R; Kleinschmidt, R V

    1921-01-01

    This report discusses the effects of roughness, smoothness, and cleanness of cooling surfaces on the performance of aeronautic radiators, as shown by experimental work, with different conditions of surface, on (1) heat transfer from a single brass tube and from a radiator; (2) pressure drop in an air stream in a single brass tube and in a radiator; (3) head resistance of a radiator; and (4) flow of air through a radiator. It is shown that while smooth surfaces are better than rough, the surfaces usually found in commercial radiators do not differ enough to show marked effect on performance, provided the surfaces are kept clean.

  6. High performance infrared fast cooled detectors for missile applications

    NASA Astrophysics Data System (ADS)

    Reibel, Yann; Espuno, Laurent; Taalat, Rachid; Sultan, Ahmad; Cassaigne, Pierre; Matallah, Noura

    2016-05-01

    SOFRADIR was selected in the late 90's for the production of 320×256 MW detectors for major European missile programs. This experience has established our company as a key player in the field of missile programs. SOFRADIR has since developed a vast portfolio of lightweight, compact and high performance JT-based solutions for missiles. ALTAN is a 384x288 Mid Wave infrared detector with 15μm pixel pitch, and is offered in a miniature ultra-fast Joule- Thomson cooled Dewar. Since Sofradir offers both Indium Antimonide (InSb) and Mercury Cadmium Telluride technologies (MCT), we are able to deliver the detectors best suited to customers' needs. In this paper we are discussing different figures of merit for very compact and innovative JT-cooled detectors and are highlighting the challenges for infrared detection technologies.

  7. Drop tower experiment for performance evaluation of gas-liquid equilibrium thruster for small spacecraft

    NASA Astrophysics Data System (ADS)

    Motooka, Norizumi; Yamamoto, Takayuki; Mori, Osamu; Okano, Yoshinobu; Kishino, Yoshihiro; Kawaguchi, Junichiro

    JAXA/ISAS is developing the gas-liquid equilibrium thruster for a small spacecraft. In small spacecrafts, the thruster system must be simple and its weight must be light. This thruster system uses HFC-134a (1,1,1,2-tetrafluoroethane) , a kind of liquefied gas, as propellant because of its harmlessness and ease of handling. And this thruster stores propellant as liquid in the tank and ejects propellant as gas using the gas-liquid equilibrium pressure to produce thrust, so the propellant tank only needs to resist the vapor pressure of propellant. In this thruster system, the porous metal is also equipped in the tank for the following performance advantages: (1) liquid fuel retention: The porous metal reduces sloshing problems which cause bad effects on spacecraft attitude by retaining liquid propellant inside the porous metal: (2) vapor-liquid separation: The porous metal also helps propellant separate gas from liquid by advancing propellant vaporization on its large surface area and retaining liquid propellant using its surface tension. In last autumn, we carried out the experiment to evaluate these two advantages of porous metal under micro gravity condition using 50 meters drop tower in Hokkaido, Japan. The system of this experiment divides into two different systems. The first one evaluates liquid propellant retention performance by adding disturbance to liquid propellant absorbed in porous metal. The disturbance is centrifugal force and angular acceleration worked on the liquid propellant by rotating propellant tank controlled by motor. A high speed camera records the behavior of the liquid propellant. The other one evaluates the ability of gas-liquid separation on the case of propellant ejection. In this evaluation, the parameters are full filling porous metal or some ullage in the tank, nozzle diameters and the filling ratio of liquid propellant in the tank. As for (1) liquid fuel retention, in all conducted cases without propellant ejection, liquid propellant

  8. Collapsible Towers

    NASA Technical Reports Server (NTRS)

    1976-01-01

    NASA needed a means of orbiting a large radio telescope antenna. Astro Research Corporation developed a new structure that was strong, lightweight, folded into a small storage space, and could be erected by rotation. Later they adapted it to commercial use. Today the "Astromast" tower consists of tubular aluminum alloy and stainless steel members that deploy into small three-sided bays, each made rigid by six diagonal cables. All joints are flexible to permit folding and unfolding. Tower packs into container 5% of its height, can be erected without tools and is reusable. Tower has won "Design of the Year" award from Machine Design. Variations include portable emergency bridges and commercial scaffolding.

  9. Computer Simulation Performed for Columbia Project Cooling System

    NASA Technical Reports Server (NTRS)

    Ahmad, Jasim

    2005-01-01

    This demo shows a high-fidelity simulation of the air flow in the main computer room housing the Columbia (10,024 intel titanium processors) system. The simulation asseses the performance of the cooling system and identified deficiencies, and recommended modifications to eliminate them. It used two in house software packages on NAS supercomputers: Chimera Grid tools to generate a geometric model of the computer room, OVERFLOW-2 code for fluid and thermal simulation. This state-of-the-art technology can be easily extended to provide a general capability for air flow analyses on any modern computer room. Columbia_CFD_black.tiff

  10. Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

    NASA Astrophysics Data System (ADS)

    Harber, H.

    1981-09-01

    The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

  11. Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

    NASA Technical Reports Server (NTRS)

    Harber, H.

    1981-01-01

    The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

  12. Thermal Performance Testing of EMU and CSAFE Liquid Cooling Garments

    NASA Technical Reports Server (NTRS)

    Rhodes, Richard; Bue, Grant; Hakam, Mark; Radford, Tamara

    2013-01-01

    Future exploration missions require the development of a new liquid cooling garment (LCG) that offers greater system reliability, is more comfortable, and maximizes thermal performance. To inform the development of a future LCG a thermal performance test was conducted to evaluate three factors: (1) the effect of the thermal comfort undergarment (TCU) on tactile and thermal comfort, (2) the comparable thermal performance of an CSAFE developed engineering evaluation unit (EEU) LCG, which uses a commercial-off-the-shelf (COTS) wicking garment as the base, and (3) the performance of a torso or upper body only LCG configuration to evaluate a proposed auxiliary loop configuration. To evaluate the thermal performance of each configuration a metabolic suit test was conducted, utilizing suited subjects to generate metabolic heat by walking on a treadmill at various speeds. Three (3) test subjects of similar height and weight produced a metabolic load for five tests by either resting (300-600 BTU/hr), walking at a slow pace (1200 BTU/hr), and walking at a brisk pace (2200 BTU/hr). During the test, data was collected that would allow us to track the heat transfer to the LCG and ventilation system to determine the thermal performance of the LCG configurations. Four different test configurations were tested, with one configuration tested twice. The test results show that the CSAFE EEU LCG and EMU LCG had comparable performance. The testing also showed that an auxiliary loop LCG, sized similarly to the shirt-only configuration, should provide adequate cooling for contingency scenarios. Finally, the testing showed the previous analysis that assumed a UA deterioration from the TCU was too conservative and the TCU may prove to be acceptable for future development with additional analysis and testing.

  13. Impact of ambient pressure on performance of desiccant cooling systems

    SciTech Connect

    Pesaran, A.A.

    1991-12-01

    The impact of ambient pressure on the performance of the ventilation cycle desiccant cooling system and its components was studied using computer simulations. The impact of ambient pressure depended on whether the system was designed for fixed-mass flow rate or fixed-volume flow rate operation. As ambient pressure decreased from 1.0 to 0.8 atm, the system thermal coefficient of performance increased by 8% for both fixed-mass and fixed-volume flow rate, the cooling capacity of the system (in kW) was decreased by 14% for the fixed-volume flow rate system and increased by 7% for the fixed-mass flow rate system, the electric power requirements for the system with fixed-volume flow rate did not change, and the electric power requirement for the fixed-mass flow rate system increased by 44%. The overall coefficient of performance increased up to 5% for the fixed-volume flow rate systems, and decreased up to 4% for the fixed-mass flow rate system. 16 refs.

  14. Neck-cooling improves repeated sprint performance in the heat

    PubMed Central

    Sunderland, Caroline; Stevens, Ryan; Everson, Bethan; Tyler, Christopher J.

    2015-01-01

    The present study evaluated the effect of neck-cooling during exercise on repeated sprint ability in a hot environment. Seven team-sport playing males completed two experimental trials involving repeated sprint exercise (5 × 6 s) before and after two 45 min bouts of a football specific intermittent treadmill protocol in the heat (33.0 ± 0.2°C; 53 ± 2% relative humidity). Participants wore a neck-cooling collar in one of the trials (CC). Mean power output and peak power output declined over time in both trials but were higher in CC (540 ± 99 v 507 ± 122 W, d = 0.32; 719 ± 158 v 680 ± 182 W, d = 0.24 respectively). The improved power output was particularly pronounced (d = 0.51–0.88) after the 2nd 45 min bout but the CC had no effect on % fatigue. The collar lowered neck temperature and the thermal sensation of the neck (P < 0.001) but had no effect on heart rate, fluid loss, fluid consumption, lactate, glucose, plasma volume change, cortisol, or thermal sensation (P > 0.05). There were no trial differences but interaction effects were demonstrated for prolactin concentration and rating of perceived exertion (RPE). Prolactin concentration was initially higher in the collar cold trial and then was lower from 45 min onwards (interaction trial × time P = 0.04). RPE was lower during the football intermittent treadmill protocol in the collar cold trial (interaction trial × time P = 0.01). Neck-cooling during exercise improves repeated sprint performance in a hot environment without altering physiological or neuroendocrinological responses. RPE is reduced and may partially explain the performance improvement. PMID:26594177

  15. New Directions for Evaporative Cooling Systems.

    ERIC Educational Resources Information Center

    Robison, Rita

    1981-01-01

    New energy saving technology can be applied to older cooling towers; in addition, evaporative chilling, a process that links a cooling tower to the chilling equipment, can reduce energy use by 80 percent. (Author/MLF)

  16. Conjugate heat transfer investigation on the cooling performance of air cooled turbine blade with thermal barrier coating

    NASA Astrophysics Data System (ADS)

    Ji, Yongbin; Ma, Chao; Ge, Bing; Zang, Shusheng

    2016-08-01

    A hot wind tunnel of annular cascade test rig is established for measuring temperature distribution on a real gas turbine blade surface with infrared camera. Besides, conjugate heat transfer numerical simulation is performed to obtain cooling efficiency distribution on both blade substrate surface and coating surface for comparison. The effect of thermal barrier coating on the overall cooling performance for blades is compared under varied mass flow rate of coolant, and spatial difference is also discussed. Results indicate that the cooling efficiency in the leading edge and trailing edge areas of the blade is the lowest. The cooling performance is not only influenced by the internal cooling structures layout inside the blade but also by the flow condition of the mainstream in the external cascade path. Thermal barrier effects of the coating vary at different regions of the blade surface, where higher internal cooling performance exists, more effective the thermal barrier will be, which means the thermal protection effect of coatings is remarkable in these regions. At the designed mass flow ratio condition, the cooling efficiency on the pressure side varies by 0.13 for the coating surface and substrate surface, while this value is 0.09 on the suction side.

  17. Application of the hampel's method to approximate a theoretical model of the cooling tower in the two-dimensional approach. (Polish Title: Zastosowanie metody Hampela do aproksymacji modelu teoretycznego chłodni kominowej w podejściu dwuwymiarowym)

    NASA Astrophysics Data System (ADS)

    Muszyński, Z.

    2013-12-01

    Correct assessment of construction safety requires reliable information about geometrical shape of the analyzed object. The least square method is the most popular method to calculate object deviation between theoretical geometry and the real object shape measured with geodetic methods. The paper presents the possibility of using robust estimation methods on the example of Hampel's method. Deviation values obtained in this way are resistant to outliers influence and are more reliable. This problem is illustrated by a hyperbola which is approximated in survey points (measured by terrestrial laser scanning) localized on the generating line of the cooling tower shell in one of its axial vertical cross-section.

  18. Performance Prediction Method of CO2 Cycle for Air Cooling

    NASA Astrophysics Data System (ADS)

    Koyama, Shigeru; Xue, Jun; Kuwahara, Ken

    From the perspective of global environmental protection and energy-saving, the research and development on high-efficiency heat pump and refrigeration systems using environment-friendly refrigerants have become one of the most important issues in the air-conditioning and refrigeration sector. In the present work, a steady-state model of the CO2 transcritical cycle for air cooling, which consists of a rotary compressor, a fin-tube gas cooler,a fin-tube evaporator and an expansion valve, has been developed. The detailed model of fin-tube heat exchanger has been constructed by means of the finite volume method, in which the local heat transfer and flow characteristics are evaluated. It should be noted that the effects of the dew condensation generated on the cooling surface are considered in the evaporator model. As a calculation example, the effects of the indoor air wet-bulb temperature on the cycle performance have been examined with this developed simulator.

  19. Tower counts

    USGS Publications Warehouse

    Woody, Carol Ann; Johnson, D.H.; Shrier, Brianna M.; O'Neal, Jennifer S.; Knutzen, John A.; Augerot, Xanthippe; O'Neal, Thomas A.; Pearsons, Todd N.

    2007-01-01

    Counting towers provide an accurate, low-cost, low-maintenance, low-technology, and easily mobilized escapement estimation program compared to other methods (e.g., weirs, hydroacoustics, mark-recapture, and aerial surveys) (Thompson 1962; Siebel 1967; Cousens et al. 1982; Symons and Waldichuk 1984; Anderson 2000; Alaska Department of Fish and Game 2003). Counting tower data has been found to be consistent with that of digital video counts (Edwards 2005). Counting towers do not interfere with natural fish migration patterns, nor are fish handled or stressed; however, their use is generally limited to clear rivers that meet specific site selection criteria. The data provided by counting tower sampling allow fishery managers to determine reproductive population size, estimate total return (escapement + catch) and its uncertainty, evaluate population productivity and trends, set harvest rates, determine spawning escapement goals, and forecast future returns (Alaska Department of Fish and Game 1974-2000 and 1975-2004). The number of spawning fish is determined by subtracting subsistence, sport-caught fish, and prespawn mortality from the total estimated escapement. The methods outlined in this protocol for tower counts can be used to provide reasonable estimates ( plus or minus 6%-10%) of reproductive salmon population size and run timing in clear rivers. 

  20. PERFORMANCE STUDY OF LIQUID NITROGEN THERMO-SIPHON COOLING LOOP

    SciTech Connect

    Kar, S.; Kumar, M.; Choudhury, A.; Datta, T. S.; Chorowski, M.; Polinski, J.

    2010-04-09

    A RF-superconducting linear accelerator (LINAC) booster for the existing 15 UD Pelletron accelerator is presently under construction at Inter-University Accelerator Centre in New Delhi, India. The LINAC will make use of superconducting niobium quarter-wave resonators (QWR) as the accelerating element, and will consist of three accelerating cryomodules. A gravity-assisted (thermo-siphon) flow scheme with liquid nitrogen has been proposed to cool the thermal radiation shields of the LINAC cryomodules. A small test rig of the thermo-siphon loop has been developed to simulate and investigate the chosen aspects of the proposed configuration. The experimental work has been focused on the thermal performances of the specially designed copper clamps and optimization of the system engineering parameters. The paper presents the results of the thermo-siphon measurements and the qualitative description of the investigated phenomena.

  1. THE SNS RESONANCE CONTROL COOLING SYSTEM CONTROL VALVE UPGRADE PERFORMANCE

    SciTech Connect

    Williams, Derrick C; Schubert, James Phillip; Tang, Johnny Y

    2008-01-01

    The normal-conducting linac of the Spallation Neutron Source (SNS) uses 10 separate Resonance Control Cooling System (RCCS) water skids to control the resonance of 6 Drift Tube Linac (DTL) and 4 Coupled Cavity Linac (CCL) accelerating structures. The RCCS water skids use 2 control valves; one to regulate the chilled water flow and the other to bypass water to a chilled water heat exchanger. These valves have hydraulic actuators that provide position and feedback to the control system. Frequency oscillations occur using these hydraulic actuators due to their coarse movement and control of the valves. New pneumatic actuator and control positioners have been installed on the DTL3 RCCS water skid to give finer control and regulation of DTL3 cavity temperature. This paper shows a comparison of resonance control performance for the two valve configurations.

  2. Thermal Performance Testing of EMU and OSS Liquid Cooling Garments

    NASA Technical Reports Server (NTRS)

    Rhodes, Richard; Bue, Grant; Hakam, Mary

    2012-01-01

    A test was conducted to evaluate three factors influencing the thermal performance of liquid cooling garments (LCG): (1) the comparable thermal performance of an Oceaneering developed engineering evaluation unit (EEU) prototype LDG, (2) the effect of the thermal comfort undergarment (TCU), and (3) the performance of a torso or upper body only LCG configuration. To evaluate the thermal performance of each configuration a metabolic test was conducted, utilizing suited subjects to generate the metabolic heat. For this study three (3) test subjects of similar health and weight produced a metabolic load on the LDG configuration by either resting (300-600 BTU/hr), walking at a slow pace (1200 BRU/hr), and walking at a brisk pace (2200 BTU/hr), as outlined in Figure 1, the metabolic profile. During the test, oxygen consumption, heart rate, relative humidity, air flow, inlet and outlet air pressure, inlet and outlet air temperature, delta air temperature, water flow (100 lb/hr), inlet water temperature (64 F), delta water temperature, water pressure, core body temperature, skin temperature, and sweat loss data was recorded. Four different test configurations were tested, with one configuration tested twice, as outlined in Table 1. The test was conducted with the suit subjects wearing the Demonstrator Suit, pressurized to vent pressure (approximately 0.5 psig). The demonstrator suit has an integrated ventilation duct system and was used to create a relevant environment with a captured ventilation return, an integrated vent tree, and thermal insulation from the environment.

  3. Effects of geometry on slot-jet film cooling performance

    SciTech Connect

    Hyams, D.G.; McGovern, K.T.; Leylek, J.H.

    1995-10-01

    The physics of the film cooling process for shaped, inclined slot-jets with realistic slot-length-to-width ratios (L/s) is studied for a range of blowing ratio (M) and density ratio (DR) parameters typical of gas turbine operations. For the first time in the open literature, the effect of inlet and exit shaping of the slot-jet on both flow and thermal field characteristics is isolated, and the dominant mechanisms responsible for differences in these characteristics are documented. A previously documented computational methodology was applied for the study of four distinct configurations: (1) slot with straight edges and sharp corners (reference case); (2) slot with shaped inlet region; (3) slot with shaped exit region; and (4) slot with both shaped inlet and exit regions. Detailed field results as well as surface phenomena involving adiabatic film effectiveness ({eta}) and heat transfer coefficient (h) are presented. It is demonstrated that both {eta} and h results are vital in the proper assessment of film cooling performance. All simulations were carried out using a multi-block, unstructured/adaptive grid, fully explicit, time-marching solver with multi-grid, local time stepping, and residual smoothing type acceleration techniques. Special attention was paid to and full documentation provided for: (1) proper modeling of the physical phenomena; (2) exact geometry and high quality grid generation techniques; (3) discretization schemes; and (4) turbulence modeling issues. The key parameters M and DR were varied from 1.0 to 2.0 and 1.5 to 2.0, respectively, to show their influence. Simulations were repeated for slot length-to-width ratio (L/s) of 3.0 and 4.5 in order to explain the effects of this important parameter. Additionally, the performance of two popular turbulence models, standard k-F, and RNG k-E, were studied to establish their ability to handle highly elliptic jet/crossflow interaction type processes.

  4. Experiences in solar cooling systems

    NASA Astrophysics Data System (ADS)

    Ward, D. S.

    The results of performance evaluations for nine solar cooling systems are presented, and reasons fow low or high net energy balances are discussed. Six of the nine systems are noted to have performed unfavorably compared to standard cooling systems due to thermal storage losses, excessive system electrical demands, inappropriate control strategies, poor system-to-load matching, and poor chiller performance. A reduction in heat losses in one residential unit increased the total system efficiency by 2.5%, while eliminating heat losses to the building interior increased the efficiency by 3.3%. The best system incorporated a lithium bromide absorption chiller and a Rankine cycle compression unit for a commercial application. Improvements in the cooling tower and fan configurations to increase the solar cooling system efficiency are indicated. Best performances are expected to occur in climates inducing high annual cooling loads.

  5. Sorting Test, Tower Test, and BRIEF-SR do not predict school performance of healthy adolescents in preuniversity education

    PubMed Central

    Boschloo, Annemarie; Krabbendam, Lydia; Aben, Aukje; de Groot, Renate; Jolles, Jelle

    2014-01-01

    Executive functions (EF) such as self-monitoring, planning, and organizing are known to develop through childhood and adolescence. They are of potential importance for learning and school performance. Earlier research into the relation between EF and school performance did not provide clear results possibly because confounding factors such as educational track, boy-girl differences, and parental education were not taken into account. The present study therefore investigated the relation between executive function tests and school performance in a highly controlled sample of 173 healthy adolescents aged 12–18. Only students in the pre-university educational track were used and the performance of boys was compared to that of girls. Results showed that there was no relation between the report marks obtained and the performance on executive function tests, notably the Sorting Test and the Tower Test of the Delis-Kaplan Executive Functions System (D-KEFS). Likewise, no relation was found between the report marks and the scores on the Behavior Rating Inventory of Executive Function—Self-Report Version (BRIEF-SR) after these were controlled for grade, sex, and level of parental education. The findings indicate that executive functioning as measured with widely used instruments such as the BRIEF-SR does not predict school performance of adolescents in preuniversity education any better than a student's grade, sex, and level of parental education. PMID:24782794

  6. Performance Evaluation of a 4.5 kW (1.3 Refrigeration Tons) Air-Cooled Lithium Bromide/Water Solar Powered (Hot-Water-Fired) Absorption Unit

    SciTech Connect

    Zaltash, Abdolreza; Petrov, Andrei Y; Linkous, Randall Lee; Vineyard, Edward Allan

    2007-01-01

    During the summer months, air-conditioning (cooling) is the single largest use of electricity in both residential and commercial buildings with the major impact on peak electric demand. Improved air-conditioning technology has by far the greatest potential impact on the electric industry compared to any other technology that uses electricity. Thermally activated absorption air-conditioning (absorption chillers) can provide overall peak load reduction and electric grid relief for summer peak demand. This innovative absorption technology is based on integrated rotating heat exchangers to enhance heat and mass transfer resulting in a potential reduction of size, cost, and weight of the "next generation" absorption units. Rotartica Absorption Chiller (RAC) is a 4.5 kW (1.3 refrigeration tons or RT) air-cooled lithium bromide (LiBr)/water unit powered by hot water generated using the solar energy and/or waste heat. Typically LiBr/water absorption chillers are water-cooled units which use a cooling tower to reject heat. Cooling towers require a large amount of space, increase start-up and maintenance costs. However, RAC is an air-cooled absorption chiller (no cooling tower). The purpose of this evaluation is to verify RAC performance by comparing the Coefficient of Performance (COP or ratio of cooling capacity to energy input) and the cooling capacity results with those of the manufacturer. The performance of the RAC was tested at Oak Ridge National Laboratory (ORNL) in a controlled environment at various hot and chilled water flow rates, air handler flow rates, and ambient temperatures. Temperature probes, mass flow meters, rotational speed measuring device, pressure transducers, and a web camera mounted inside the unit were used to monitor the RAC via a web control-based data acquisition system using Automated Logic Controller (ALC). Results showed a COP and cooling capacity of approximately 0.58 and 3.7 kW respectively at 35 C (95 F) design condition for ambient

  7. Rapunzel's Tower

    ERIC Educational Resources Information Center

    Depp, Sheryl

    2007-01-01

    Children's literature often inspires the author's lessons, and reading to her primary students motivates their participation. In this article, the author presents and describes her lesson which is based on the book "Falling for Rapunzel" by Leah Wilcox. Students created a fairy tale tower in this lesson, which took place over three class periods.…

  8. Performance of active solar space-cooling systems: The 1980 cooling season

    NASA Astrophysics Data System (ADS)

    Blum, D.; Frock, S.; Logee, T.; Missal, D.; Wetzel, P.

    1980-12-01

    Solar cooling by an absorption chiller is not a cost effective method to use solar heat. This statement is substantiated by careful analysis of each subsystem and equipment component. Good designs and operating procedures are identified. The problems which reduce cost effectiveness are pointed out. There are specific suggestions for improvements. Finally, there is a comparison of solar cooling by absorption chilling and using photovoltaic cells.

  9. COOLING FAN AND SYSTEM PERFORMANCE AND EFFICIENCY IMPROVEMENTS

    SciTech Connect

    Ronald Dupree

    2005-07-31

    Upcoming emissions regulations (Tiers 3, 4a and 4b) are imposing significantly higher heat loads on the cooling system than lesser regulated machines. This work was a suite of tasks aimed at reducing the parasitic losses of the cooling system, or improving the design process through six distinct tasks: 1. Develop an axial fan that will provide more airflow, with less input power and less noise. The initial plan was to use Genetic Algorithms to do an automated fan design, incorporating forward sweep for low noise. First and second generation concepts could not meet either performance or sound goals. An experienced turbomachinery designer, using a specialized CFD analysis program has taken over the design and has been able to demonstrate a 5% flow improvement (vs 10% goal) and 10% efficiency improvement (vs 10% goal) using blade twist only. 2. Fan shroud developments, using an 'aeroshroud' concept developed at Michigan State University. Performance testing at Michigan State University showed the design is capable of meeting the goal of a 10% increase in flow, but over a very narrow operating range of fan performance. The goal of 10% increase in fan efficiency was not met. Fan noise was reduced from 0 to 2dB, vs. a goal of 5dB at constant airflow. The narrow range of fan operating conditions affected by the aeroshroud makes this concept unattractive for further development at this time 3. Improved axial fan system modeling is needed to accommodate the numbers of cooling systems to be redesigned to meet lower emissions requirements. A CFD fan system modeling guide has been completed and transferred to design engineers. Current, uncontrolled modeling practices produce flow estimates in some cases within 5% of measured values, and in some cases within 25% of measured values. The techniques in the modeling guide reduced variability to the goal of + 5% for the case under study. 4. Demonstrate the performance and design versatility of a high performance fan. A 'swept blade

  10. Dynamic performance testing of prototype 3 ton air-cooled carrier absorption chiller

    NASA Astrophysics Data System (ADS)

    Borst, R. R.; Wood, B. D.

    1985-05-01

    The performance of a prototype three ton cooling capacity air-cooled lithium bromide/water absorption chiller was tested using an absorption chiller test facility which was modified to expand its testing capabilities to include air-cooled chillers in addition to water-cooled chillers. Temperatures of the three externally supplied fluid loops: hot water, chilled water, and cooling air, were varied in order to determine the effects this would have on the two principal measures of chiller performance: cooling capacity and thermal coefficient of performance (COP). A number of interrelated factors were identified as contributing to less than expected performance. For comparison, experimental correlations of other investigators for this and other similar absorption chillers are presented. These have been plotted as both contour and three-dimensional performance maps in order to more clearly show the functional dependence of the chiller performance on the fluid loop temperatures.

  11. Preliminary analysis of effects of air cooling turbine blades on turbojet-engine performance

    NASA Technical Reports Server (NTRS)

    Schramm, Wilson B; Nachtigall, Alfred J; Arne, Vernon L

    1950-01-01

    The effects of turbine-blade cooling on engine performance were analytically investigated for a turbojet engine in which cooling air is bled from the engine compressor. The analysis was made for a constant turbine-inlet temperature and a range of altitudes to determine the minimum cooling requirements to permit substitution of nonstrategic materials in turbine blading. The results indicate that, for a constant inlet temperature, air cooling of the turbine blades increases the specific fuel consumption and decreases the thrust of the engine. The highest possible cooling effectiveness is desirable to minimize coolant weight flow and its effects on engine performance.

  12. Process of making cryogenically cooled high thermal performance crystal optics

    DOEpatents

    Kuzay, T.M.

    1992-06-23

    A method is disclosed for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N[sub 2] is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation. 7 figs.

  13. Process of making cryogenically cooled high thermal performance crystal optics

    DOEpatents

    Kuzay, Tuncer M.

    1992-01-01

    A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N.sub.2 is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.

  14. Performance of a transpiration-regenerative cooled rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Valler, H. W.

    1979-01-01

    The analysis, design, fabrication, and testing of a liquid rocket engine thrust chamber which is gas transpiration cooled in the high heat flux convergent portion of the chamber and water jacket cooled (simulated regenerative) in the barrel and divergent sections of the chamber are described. The engine burns LOX-hydrogen propellants at a chamber pressure of 600 psia. Various transpiration coolant flow rates were tested with resultant local hot gas wall temperatures in the 800 F to 1400 F range. The feasibility of transpiration cooling with hydrogen and helium, and the use of photo-etched copper platelets for heat transfer and coolant metering was successfully demonstrated.

  15. Process of making cryogenically cooled high thermal performance crystal optics

    SciTech Connect

    Kuzay, T.M.

    1990-06-29

    A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N{sub 2} is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.

  16. Tower of Hanoi Performance of Retarded Young Adults and Nonretarded Children as a Function of Solution Length and Goal State.

    ERIC Educational Resources Information Center

    Borys, Suzanne V.; And Others

    1982-01-01

    Three experiments were conducted with the Tower of Hanoi task to assess problem-solving ability in 6-, 7-, 8-, and 10-year-old nonretarded children and mentally retarded young adults of varying maturational ages. (Author/MP)

  17. Tower-scale performance of four observation-based evapotranspiration algorithms within the WACMOS-ET project

    NASA Astrophysics Data System (ADS)

    Michel, Dominik; Miralles, Diego; Jimenez, Carlos; Ershadi, Ali; McCabe, Matthew F.; Hirschi, Martin; Seneviratne, Sonia I.; Jung, Martin; Wood, Eric F.; (Bob) Su, Z.; Timmermans, Joris; Chen, Xuelong; Fisher, Joshua B.; Mu, Quiaozen; Fernandez, Diego

    2015-04-01

    Research on climate variations and the development of predictive capabilities largely rely on globally available reference data series of the different components of the energy and water cycles. Several efforts have recently aimed at producing large-scale and long-term reference data sets of these components, e.g. based on in situ observations and remote sensing, in order to allow for diagnostic analyses of the drivers of temporal variations in the climate system. Evapotranspiration (ET) is an essential component of the energy and water cycle, which cannot be monitored directly on a global scale by remote sensing techniques. In recent years, several global multi-year ET data sets have been derived from remote sensing-based estimates, observation-driven land surface model simulations or atmospheric reanalyses. The LandFlux-EVAL initiative presented an ensemble-evaluation of these data sets over the time periods 1989-1995 and 1989-2005 (Mueller et al. 2013). The WACMOS-ET project (http://wacmoset.estellus.eu) started in the year 2012 and constitutes an ESA contribution to the GEWEX initiative LandFlux. It focuses on advancing the development of ET estimates at global, regional and tower scales. WACMOS-ET aims at developing a Reference Input Data Set exploiting European Earth Observations assets and deriving ET estimates produced by a set of four ET algorithms covering the period 2005-2007. The algorithms used are the SEBS (Su et al., 2002), Penman-Monteith from MODIS (Mu et al., 2011), the Priestley and Taylor JPL model (Fisher et al., 2008) and GLEAM (Miralles et al., 2011). The algorithms are run with Fluxnet tower observations, reanalysis data (ERA-Interim), and satellite forcings. They are cross-compared and validated against in-situ data. In this presentation the performance of the different ET algorithms with respect to different temporal resolutions, hydrological regimes, land cover types (including grassland, cropland, shrubland, vegetation mosaic, savanna

  18. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cooling Performance and Cost for Central Air Conditioners H Appendix H to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC... RULEâ) Pt. 305, App. H Appendix H to Part 305—Cooling Performance and Cost for Central Air...

  19. Water cooling considerations for the SSC

    SciTech Connect

    O'Meara, J.

    1984-11-02

    The purpose of this note is to specify parameters for hypothetical SSC water cooling systems, in order that the comparative advantages of these system can be studied. The various methods of heat rejection considered include: cooling towers, cooling ponds, ground water recharge system, water-to-air (dry) cooling towers, use of tunnel sump water, or some combination.

  20. Drop tower with no aerodynamic drag

    NASA Technical Reports Server (NTRS)

    Kendall, J. M., Jr.

    1981-01-01

    Cooling air accelerated to match velocity of falling object eliminates drag. 3 meter drop tower with suction fan and specific geometry causes air to accelerate downward at 1 g. Although cooling of molten material released from top is slow because surrounding air moves with it, drop remains nearly spherical.

  1. Energy Performance Assessment of Radiant Cooling System through Modeling and Calibration at Component Level

    SciTech Connect

    Khan, Yasin; Mathur, Jyotirmay; Bhandari, Mahabir S

    2016-01-01

    The paper describes a case study of an information technology office building with a radiant cooling system and a conventional variable air volume (VAV) system installed side by side so that performancecan be compared. First, a 3D model of the building involving architecture, occupancy, and HVAC operation was developed in EnergyPlus, a simulation tool. Second, a different calibration methodology was applied to develop the base case for assessing the energy saving potential. This paper details the calibration of the whole building energy model to the component level, including lighting, equipment, and HVAC components such as chillers, pumps, cooling towers, fans, etc. Also a new methodology for the systematic selection of influence parameter has been developed for the calibration of a simulated model which requires large time for the execution. The error at the whole building level [measured in mean bias error (MBE)] is 0.2%, and the coefficient of variation of root mean square error (CvRMSE) is 3.2%. The total errors in HVAC at the hourly are MBE = 8.7% and CvRMSE = 23.9%, which meet the criteria of ASHRAE 14 (2002) for hourly calibration. Different suggestions have been pointed out to generalize the energy saving of radiant cooling system through the existing building system. So a base case model was developed by using the calibrated model for quantifying the energy saving potential of the radiant cooling system. It was found that a base case radiant cooling system integrated with DOAS can save 28% energy compared with the conventional VAV system.

  2. Effect of Propeller on Engine Cooling System Drag and Performance

    NASA Technical Reports Server (NTRS)

    Katz, Joseph; Corsiglia, Victor R.; Barlow, Philip R.

    1982-01-01

    The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was Investigated experimentally. The semispan model was mounted vertically in the 40 x 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-now configuration. It was found that the propeller slip-stream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slip-stream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack; that is, climb condition. For the cruise condition those improvements were more moderate.

  3. NASA's Marshall Space Flight Center Improves Cooling System Performance

    SciTech Connect

    2011-02-22

    National Aeronautics and Space Administration’s (NASA) Marshall Space Flight Center (MSFC) has a longstanding sustainability program that revolves around energy and water efficiency as well as environmental protection. MSFC identified a problematic cooling loop with six separate compressor heat exchangers and a history of poor efficiency. The facility engineering team at MSFC partnered with Flozone Services, Incorporated to implement a comprehensive water treatment platform to improve the overall efficiency of the system.

  4. High Performance Mars Liquid Cooling and Ventilation Garment Project

    NASA Technical Reports Server (NTRS)

    Terrier, Douglas; Clayton, Ronald; Whitlock, David; Conger, Bruce

    2015-01-01

    EVA space suit mobility in micro-gravity is enough of a challenge and in the gravity of Mars, improvements in mobility will enable the suited crew member to efficiently complete EVA objectives. The idea proposed is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area in order to free up the arms and legs by removing the liquid tubes currently used in the ISS EVA suit in the limbs. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased to provide the entire liquid cooling requirement and increase mobility by freeing up the arms and legs. Additional potential benefits of this approach include reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development.

  5. Pre-cooling and sports performance: a meta-analytical review.

    PubMed

    Wegmann, Melissa; Faude, Oliver; Poppendieck, Wigand; Hecksteden, Anne; Fröhlich, Michael; Meyer, Tim

    2012-07-01

    Pre-cooling is used by many athletes for the purpose of reducing body temperature prior to exercise and, consequently, decreasing heat stress and improving performance. Although there are a considerable number of studies showing beneficial effects of pre-cooling, definite conclusions on the effectiveness of pre-cooling on performance cannot yet be drawn. Moreover, detailed analyses of the specific conditions under which pre-cooling may be most promising are, so far, missing. Therefore, we conducted a literature search and located 27 peer-reviewed randomized controlled trials, which addressed the effects of pre-cooling on performance. These studies were analysed with regard to performance effects and several test circumstances (environmental temperature, test protocol, cooling method, aerobic capacity of the subjects). Eighteen studies were performed in a hot (>26°C) environment and eight in a moderate. The cooling protocols were water application (n = 12), cooling packs (n = 3), cold drinks (n = 2), cooling vest (n = 6) and a cooled room (n = 4). The following different performance tests were used: short-term, high-intensity sprints (n = 2), intermittent sprints (n = 6), time trials (n = 10), open-end tests (n = 7) and graded exercise tests (n = 2). If possible, subjects were grouped into different aerobic capacity levels according to their maximal oxygen consumption (VO(2max)): medium 55-65 mL/kg/min (n = 11) and high >65 mL/kg/min (n = 6). For all studies the relative changes of performance due to pre-cooling compared with a control condition, as well as effect sizes (Hedges' g) were calculated. Mean values were weighted according to the number of subjects in each study. Pre-cooling had a larger effect on performance in hot (+6.6%, g = 0.62) than in moderate temperatures (+1.4%, g = 0.004). The largest performance enhancements were found for endurance tests like open-end tests (+8.6%, g = 0

  6. Tower of London Performance in Healthy Adolescents: The Development of Planning Skills and Associations With Self-Reported Inattention and Impulsivity

    PubMed Central

    Luciana, Monica; Collins, Paul F.; Olson, Elizabeth A.; Schissel, Ann M.

    2014-01-01

    Studies have investigated planning skill development using the Tower of London (TOL). Reports conflict regarding maturational trajectories and associations with IQ, other executive functions, and impulsivity. A convenience sample of 9- to 20-year-olds completed the TOL and other measures. TOL accuracy improved until ages 15–17. Digit span backwards (DSB), response inhibition, and IQ were correlated with TOL performance. DSB contributed to TOL accuracy above and beyond age and IQ. Inhibitory control and DSB both contributed to the modulation of planning times across problems. Self-reported inattention and hyperactivity were associated with low performance. Task approaches reflecting planning and psychometric issues are discussed. PMID:20183711

  7. EEG Analysis of the Effects of Therapeutic Cooling on the Cognitive Performance of Multiple Sclerosis Patients

    NASA Technical Reports Server (NTRS)

    Montgomery, Leslie D.; Montgomery, Richard W.; Ku, Yu-Tsuan E.; Luna, Bernadette; Lee, Hank C.; Kliss, Mark; Webbon, Bruce; Mead, Susan C. (Technical Monitor)

    1999-01-01

    The objective of this project was to determine whether a controlled period of head and torso cooling would enhance the cognitive performance of multiple sclerosis patients. Nineteen MS patients (11 men and 8 women) participated in the study. Control data were taken from nineteen healthy volunteers (12 men and 7 women). All but six of nineteen MS patients tested improved their cognitive performance, as measured by their scores on the Rao test battery. A second objective was to gain insight into the neurological effects of cooling. Visual evoked potentials (VEPs) stimulated by a reversing checkerboard pattern were recorded before and after cooling. We found that cooling selectively benefited the cognitive performance of those MS patients whose pre-cooling VEPs were abnormally shaped (which is an indication of visual pathway impairment due to demyelinization). Moreover, for female MS patients, the degree of cognitive performance improvement following cooling was correlated with a change in the shape of their VEPs toward a more normal shape following cooling.

  8. Performance test of the cryogenic cooling system for the superconducting fault current limiter

    NASA Astrophysics Data System (ADS)

    Hong, Yong-Ju; In, Sehwan; Yeom, Han-Kil; Kim, Heesun; Kim, Hye-Rim

    2015-12-01

    A Superconducting Fault Current Limiter is an electric power device which limits the fault current immediately in a power grid. The SFCL must be cooled to below the critical temperature of high temperature superconductor modules. In general, they are submerged in sub-cooled liquid nitrogen for their stable thermal characteristics. To cool and maintain the target temperature and pressure of the sub-cooled liquid nitrogen, the cryogenic cooling system should be designed well with a cryocooler and coolant circulation devices. The pressure of the cryostat for the SFCL should be pressurized to suppress the generation of nitrogen bubbles in quench mode of the SFCL. In this study, we tested the performance of the cooling system for the prototype 154 kV SFCL, which consist of a Stirling cryocooler, a subcooling cryostat, a pressure builder and a main cryostat for the SFCL module, to verify the design of the cooling system and the electric performance of the SFCL. The normal operation condition of the main cryostat is 71 K and 500 kPa. This paper presents tests results of the overall cooling system.

  9. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    PubMed

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise. PMID:27119166

  10. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    PubMed

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise.

  11. A freely falling magneto-optical trap drop tower experiment

    NASA Astrophysics Data System (ADS)

    Könemann, T.; Brinkmann, W.; Göklü, E.; Lämmerzahl, C.; Dittus, H.; van Zoest, T.; Rasel, E. M.; Ertmer, W.; Lewoczko-Adamczyk, W.; Schiemangk, M.; Peters, A.; Vogel, A.; Johannsen, G.; Wildfang, S.; Bongs, K.; Sengstock, K.; Kajari, E.; Nandi, G.; Walser, R.; Schleich, W. P.

    2007-12-01

    We experimentally demonstrate the possibility of preparing ultracold atoms in the environment of weightlessness at the earth-bound short-term microgravity laboratory Drop Tower Bremen, a facility of ZARM - University of Bremen. Our approach is based on a freely falling magneto-optical trap (MOT) drop tower experiment performed within the ATKAT collaboration (“Atom-Catapult”) as a preliminary part of the QUANTUS pilot project (“Quantum Systems in Weightlessness”) pursuing a Bose-Einstein condensate (BEC) in microgravity at the drop tower [1, 2]. Furthermore we give a complete account of the specific drop tower requirements to realize a compact and robust setup for trapping and cooling neutral rubidium 87Rb atoms in microgravity conditions. We also present the results of the first realized freely falling MOT and further accomplished experiments during several drops. The goal of the preliminary ATKAT pilot project is to initiate a basis for extended atom-optical experiments which aim at realizing, observing and investigating ultracold quantum matter in microgravity.

  12. Influence of cooling on a bismuth-doped fiber laser and amplifier performance.

    PubMed

    Kalita, Mridu P; Yoo, Seongwoo; Sahu, Jayanta K

    2009-11-01

    We characterize bismuth-doped fibers under different excitation wavelengths. The fiber laser performance at 1179 nm was investigated, incorporating different cooling arrangements. Effective heat extraction can reduce the temperature-dependent unsaturable loss in fiber, resulting in increased laser performance. The operation of a bismuth-doped fiber amplifier at 1179 nm, at both low and high input signals, is also examined. The amplifier efficiency and the saturation power both depend on effective fiber cooling. PMID:19881653

  13. Modeling and performance of the MHTGR (Modular High-Temperature Gas-Cooled Reactor) reactor cavity cooling system

    SciTech Connect

    Conklin, J.C. )

    1990-04-01

    The Reactor Cavity Cooling System (RCCS) of the Modular High- Temperature Gas-Cooled Reactor (MHTGR) proposed by the U.S. Department of Energy is designed to remove the nuclear afterheat passively in the event that neither the heat transport system nor the shutdown cooling circulator subsystem is available. A computer dynamic simulation for the physical and mathematical modeling of and RCCS is described here. Two conclusions can be made form computations performed under the assumption of a uniform reactor vessel temperature. First, the heat transferred across the annulus from the reactor vessel and then to ambient conditions is very dependent on the surface emissivities of the reactor vessel and RCCS panels. These emissivities should be periodically checked to ensure the safety function of the RCCS. Second, the heat transfer from the reactor vessel is reduced by a maximum of 10% by the presence of steam at 1 atm in the reactor cavity annulus for an assumed constant in the transmission of radiant energy across the annulus can be expected to result in an increase in the reactor vessel temperature for the MHTGR. Further investigation of participating radiation media, including small particles, in the reactor cavity annulus is warranted. 26 refs., 7 figs., 1 tab.

  14. Analysis of the Solar Radiation Impact on Cooling Performance of the Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Fedorčák, Pavol; Košičanová, Danica; Nagy, Richard; Mlynár, Peter

    2014-11-01

    Absorption cooling at low power is a new technology which has not yet been applied to current conditioning elements. This paper analyzes the various elements of solar absorption cooling. Individual states were simulated in which working conditions were set for the capability of solar absorption cooling to balance heat loads in the room. The research is based on an experimental device (absorption units with a performance of 10kW) developed at the STU in Bratislava (currently inputs and outputs of cold sources are being measured). Outputs in this paper are processed so that they connect the entire scheme of the solar absorption cooling system (i.e. the relationship between the solar systems hot and cold storage and the absorption unit). To determine the size of the storage required, calculated cooling for summer months is considered by the ramp rate of the absorption unit and required flow rate of the collectors.

  15. Numerical Examination of the Performance of a Thermoelectric Cooler with Peltier Heating and Cooling

    NASA Astrophysics Data System (ADS)

    Kim, Chang Nyung; Kim, Jeongho

    2015-10-01

    There has recently been much progress in the development of materials with higher thermoelectric performance, leading to the design of thermoelectric devices for generation of electricity and for heating or cooling. Local heating can be achieved by current flow through an electric resistance, and local heating and cooling can be performed by Peltier heating and cooling. In this study, we developed computer software that can be used to predict the Seebeck and Peltier effects for thermoelectric devices. The temperature, electric potential, heat flow, electric current, and coefficient of performance were determined, with the objective of investigating the Peltier effect in a thermoelectric device. In addition to Peltier heating and cooling, Joule and Thomson heating were quantitatively evaluated for the thermoelectric device.

  16. Experimental assessment of film cooling performance of short cylindrical holes on a flat surface

    NASA Astrophysics Data System (ADS)

    Singh, Kuldeep; Premachandran, B.; Ravi, M. R.

    2016-03-01

    The present study is an experimental investigation of film-cooling over a flat surface from the short cylindrical holes. The film cooling holes used in the combustion chamber and the afterburner liner of an aero engine has length-to-diameter (L/D) typically in the range 1-2, while the cooling holes used in turbine blades has L/D > 3. Based on the classification given in the literature, cooling holes with L/D ≤ 3 are named as short holes and cooling holes with L/D > 3 are named as long holes. Short film cooling holes cause jetting of the secondary fluid whereas the secondary fluid emerging from long holes has characteristics similar to fully developed turbulent flow in pipe. In order to understand the difference in the film cooling performance of long and short cooling holes, experimental study is carried out for five values of L/D in the range 1-5, five injection angles, α = 15°-90° and five mainstream Reynolds number 1.25 × 105-6.25 × 105 and two blowing ratios, M = 0.5-1.0. The surface temperature of the test plate is monitored using infrared thermography. The results obtained from the present study showed that the film-cooling effectiveness is higher for the longest holes (L/D = 5) investigated in the present work in comparison to that for the shorter holes. Short holes are found to give better effectiveness at the lowest investigated injection angle i.e. α = 15° in the near cooling hole region, whereas film cooling effectiveness obtained at injection angle, α = 45° is found to be better than other injection angles for longest investigated holes, i.e. L/D = 5.

  17. Cryogenic performance of a conduction-cooling splittable quadrupole magnet for ILC cryomodules

    SciTech Connect

    Kimura, N.; Yamamoto, A.; Andreev, N.; Kashikhin, V. S.; Tartaglia, M. A.; Kerby, J.; Takahashi, M.; Tosaka, T.

    2014-01-29

    A conduction-cooled splittable superconducting quadrupole magnet was designed and fabricated at Fermilab for use in cryomodules of the International Linear Collider (ILC) type, in which the magnet was to be assembled around the beam tube to avoid contaminating the ultraclean superconducting radio frequency cavity volume. This quadrupole was first tested in a liquid helium bath environment at Fermilab, where its quench and magnetic properties were characterized. Because the device is to be cooled by conduction when installed in cryomodules, a separate test with a conduction-cooled configuration was planned at KEK and Fermilab. The magnet was converted to a conduction-cooled configuration by adding conduction-cooling passages made of high-purity aluminum. Efforts to convert and refabricate the magnet into a cryostat equipped with a double-stage pulse-tube-type cryocooler began in 2011, and a thermal performance test, including a magnet excitation test of up to 30 A, was conducted at KEK. In this test, the magnet with the conduction-cooled configuration was successfully cooled to 4 K within 190 h, with an acceptable heat load of less than 1 W at 4 K. It was also confirmed that the conduction-cooled splittable superconducting quadrupole magnet was practical for use in ILC-type cryomodules.

  18. Cryogenic performance of a conduction-cooling splittable quadrupole magnet for ILC cryomodules

    NASA Astrophysics Data System (ADS)

    Kimura, N.; Andreev, N.; Kashikhin, V. S.; Kerby, J.; Takahashi, M.; Tartaglia, M. A.; Tosaka, T.; Yamamoto, A.

    2014-01-01

    A conduction-cooled splittable superconducting quadrupole magnet was designed and fabricated at Fermilab for use in cryomodules of the International Linear Collider (ILC) type, in which the magnet was to be assembled around the beam tube to avoid contaminating the ultraclean superconducting radio frequency cavity volume. This quadrupole was first tested in a liquid helium bath environment at Fermilab, where its quench and magnetic properties were characterized. Because the device is to be cooled by conduction when installed in cryomodules, a separate test with a conduction-cooled configuration was planned at KEK and Fermilab. The magnet was converted to a conduction-cooled configuration by adding conduction-cooling passages made of high-purity aluminum. Efforts to convert and refabricate the magnet into a cryostat equipped with a double-stage pulse-tube-type cryocooler began in 2011, and a thermal performance test, including a magnet excitation test of up to 30 A, was conducted at KEK. In this test, the magnet with the conduction-cooled configuration was successfully cooled to 4 K within 190 h, with an acceptable heat load of less than 1 W at 4 K. It was also confirmed that the conduction-cooled splittable superconducting quadrupole magnet was practical for use in ILC-type cryomodules.

  19. Cold-air annular-cascade investigation of aerodynamic performance of cooled turbine vanes. 2: Trailing-edge ejection, film cooling, and transpiration cooling

    NASA Technical Reports Server (NTRS)

    Goldman, L. J.; Mclallin, K. L.

    1975-01-01

    The aerodynamic performance of four different cooled vane configurations was experimentally determined in a full-annular cascade at a primary- to coolant-total-temperature ratio of 1.0. The vanes were tested over a range of coolant flow rates and pressure ratios. Overall vane efficiencies were obtained and compared, where possible, with the results obtained in a four-vane, annular-sector cascade. The vane efficiency and exit flow conditions as functions of radial position were also determined and compared with solid (uncooled) vane results.

  20. A cooling water system copper corrosion study

    SciTech Connect

    Pulkrabek, J.W.

    1998-07-01

    The plant has four units that have been operating normally for 12--33 years. Two of the units are 70 MW sister units that have copper alloy once-through condensers. The other two units are 350 MW and 500 MW units with copper alloy condensers and cooling towers. No cooling water related tube leaks had been experienced. Until 1993, the only chemicals used were sulfuric acid for pH control of the cooling tower systems and chlorine for biological control. The units were chlorinated for one hour per day per condenser. In early July 1992, their copper grab sample at the plant discharge to the river exceeded the weekly environmental limit. In fact, it was so high that there was a slim chance of coming in under their monthly average copper limit unless something was done quickly. The result of this incident was an extensive study of their plant wastewater and cooling systems. The study revealed that the elevated copper problem had existed sporadically for several years. Initially, copper control was achieved by altering the wastewater treatment processes and cooling tower blowdown flow path. Two extended trials, one with tolyltriazole (TTA) and one with a chemically modified benzotriazole (BZT) were performed. Optimal control of copper corrosion was eventually achieved by the application of a TTA treatment program in which the feed rates are adjusted based on on-line corrosion monitoring measurements. This report documents experiences and results over the past six years.

  1. Cooling during exercise in temperate conditions: impact on performance and thermoregulation.

    PubMed

    Eijsvogels, T M H; Bongers, C C W G; Veltmeijer, M T W; Moen, M H; Hopman, M

    2014-09-01

    Exercise-induced increase in core body temperature may lead to the development of hyperthermia (>40.0°C) and/or decreased performance levels. This study examined the effects of wearing a cooling vest during a 5-km time trial on thermoregulatory responses and performance. 10 male masters athletes (42±10 years) performed a 5-km time trial on a motorized treadmill in a climate chamber (25°C, 55% relative humidity) with and without a cooling vest. Split times, heart rate, core-, skin- and cooling vest temperature were measured every 500 m. Subjects also rated thermal comfort and level of perceived exertion. The cooling vest significantly decreased heart rate (p<0.05), decreased skin temperature (p<0.001) and improved thermal comfort (p<0.005) during the time trial. Time to finish the 5-km time trial and pacing strategy did not differ between the control (1 246±96 s) and cooling vest condition (1 254±98 s, p=0.85). Additionally, thermoregulatory responses, maximum core body temperature and level of perceived exertion were not different across conditions (p=0.85, p=0.49, p=0.11, respectively). In conclusion, we demonstrated that wearing a cooling vest during exercise improves thermal comfort but does not enhance performance or decrease core body temperature in male masters athletes under temperate ambient conditions. PMID:24771132

  2. Typical Mid Tower Elevation & Section, Typical Mid Tower Footing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Typical Mid Tower Elevation & Section, Typical Mid Tower Footing Section & Elevation, South Tower Section & Elevation, and North Tower Sections & Elevation - Cape Arago Light Station Footbridge, Gregory Point, Charleston, Coos County, OR

  3. Electrical performance of a Portable Protective Gap (PPG) in a compact 550-kV tower. Final report

    SciTech Connect

    Gela, G.; Lux, A.E.

    1994-11-01

    This report presents the results of a research project by Western Area Power Administration (Western) on the application of a Portable Protective Gap (PPG) to live working, on Western`s upgraded compact 550 kV tower type 51S. The objective of the project was to provide experimental evidence that confirms the needed coordination of the PPG sparkover characteristics with those of the 51S tower during live working conditions. These conditions include the presence of damaged porcelain cap-and-pin insulators, the worker, and live working tools and equipment in normal work positions. The tested PPG is a portable rod-rod 1.04 m (41 inches) gap, which would be installed on the tower adjacent to the worksite. The purpose of the PPG is to protect the worker by providing positive control of the transient overvoltage (TOV) at the worksite. That is, the PPG must operate (spark over) at a TOV level which is lower then the level that would cause a disruptive discharge (sparkover or flashover) at the worksite. The worksite disruptive discharge level. or conversely the worksite withstand level is dependent on a large number of factors, including presence and location of the worker, presence and location of live working tools and equipment, and number and location of damaged porcelain (cap-and-pin) insulators at the worksite. The PPG must not spark over at the system`s normal AC operating, voltage, i.e. its AC withstand level must be higher than AC stresses expected at the worksite.

  4. Assessing the Performance of Clostridium perfringens Cooling Models for Cooked, Uncured Meat and Poultry Products.

    PubMed

    Mohr, T B; Juneja, V K; Thippareddi, H H; Schaffner, D W; Bronstein, P A; Silverman, M; Cook, L V

    2015-08-01

    Heat-resistant spores of Clostridium perfringens may germinate and multiply in cooked meat and poultry products when the rate and extent of cooling does not occur in a timely manner. Therefore, six cooling models (PMP 7.0 broth model; PMIP uncured beef, chicken, and pork models; Smith-Schaffner version 3; and UK IFR ComBase Perfringens Predictor) were evaluated for relative performance in predicting growth of C. perfringens under dynamic temperature conditions encountered during cooling of cooked, uncured meat and poultry products. The predicted growth responses from the models were extensively compared with those observed in food. Data from 188 time-temperature cooling profiles (176 for single-rate exponential cooling and 12 for dual-rate exponential cooling) were collected from 17 independent sources (16 peer-reviewed publications and one report) for model evaluation. Data were obtained for a variety of cooked products, including meat and poultry slurries, ground meat and poultry products with and without added ingredients (e.g., potato starch, sodium triphosphate, and potassium tetrapyrophosphate), and processed products such as ham and roast beef. Performance of the models was evaluated using three sets of criteria, and accuracy was defined within a 1- to 2-log range. The percentages of accurate, fail-safe, or fail-dangerous predictions for each cooling model differed depending on which criterion was used to evaluate the data set. Nevertheless, the combined percentages of accurate and fail-safe predictions based on the three performance criteria were 34.66 to 42.61% for the PMP 7.0 beef broth model, 100% for the PMIP cooling models for uncured beef, uncured pork and uncured chicken, 80.11 to 93.18% for the Smith-Schaffner cooling model, and 74.43 to 85.23% for the UK IFR ComBase Perfringens Predictor model during single-rate exponential chilling. Except for the PMP 7.0 broth model, the other five cooling models (PMIP, Smith-Schaffner, and UK IFR ComBase) are

  5. Effects of Hole Length, Supply Plenum Geometry, and Freestream Turbulence on Film Cooling Performance

    NASA Technical Reports Server (NTRS)

    Burd, Steven W.; Simon, Terrence W.; Thurman, Douglas (Technical Monitor)

    2000-01-01

    Experimental measurements are presented in this report to document the sensitivity of film cooling performance to the hole length and coolant delivery plenum geometry. Measurements with hot-wire anemometry detail velocity, local turbulence, and spectral distributions over the exit plane of film cooling holes and downstream of injection in the coolant-freestream interaction zone. Measurements of discharge coefficients and adiabatic effectiveness are also provided. Coolant is supplied to the film cooling holes by means of a large, open plenum and through plenums which force the coolant to approach the holes either co-current or counter-current to the freestream. A single row of film cooling holes with 35 degree-inclined streamwise at two coolant-to-freestream velocity ratios, 0.5 and 1.0, is investigated. The coolant-to-freestream density ratio is maintained in the range 0.96 to 1.0. Measurements were taken under high-freestream (FSTI = 12%) and low-freestream turbulence intensity (FSTI = 0.5%) conditions. The results document the effects of the hole L/D, coolant supply plenum geometry, velocity ratio, and FSTI. In general, hole L/D and the supply plenum geometry play influential roles in the film cooling performance. Hole L/D effects, however, are more pronounced. Film cooling performance is also dependent upon the velocity ratio and FSTI.

  6. Development of a prototype thermoelectric space cooling system using phase change material to improve the performance

    NASA Astrophysics Data System (ADS)

    Zhao, Dongliang

    The thermoelectric cooling system has advantages over conventional vapor compression cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no refrigerant, being powered by direct current, and easily switching between cooling and heating modes. However, it has been long suffering from its relatively high cost and low energy efficiency, which has restricted its usage to niche applications, such as space missions, portable cooling devices, scientific and medical equipment, where coefficient of performance (COP) is not as important as reliability, energy availability, and quiet operation environment. Enhancement of thermoelectric cooling system performance generally relies on two methods: improving thermoelectric material efficiency and through thermoelectric cooling system thermal design. This research has been focused on the latter one. A prototype thermoelectric cooling system integrated with phase change material (PCM) thermal energy storage unit for space cooling has been developed. The PCM thermal storage unit used for cold storage at night, functions as the thermoelectric cooling system's heat sink during daytime's cooling period and provides relatively lower hot side temperature for the thermoelectric cooling system. The experimental test of the prototype system in a reduced-scale chamber has realized an average cooling COP of 0.87, with the maximum value of 1.22. Another comparison test for efficacy of PCM thermal storage unit shows that 35.3% electrical energy has been saved from using PCM for the thermoelectric cooling system. In general, PCM faces difficulty of poor thermal conductivity at both solid and liquid phases. This system implemented a finned inner tube to increase heat transfer during PCM charging (melting) process that directly impacts thermoelectric system's performance. A simulation tool for the entire system has been developed including mathematical models for a single thermoelectric module

  7. Improving of the photovoltaic / thermal system performance using water cooling technique

    NASA Astrophysics Data System (ADS)

    Hussien, Hashim A.; Numan, Ali H.; Abdulmunem, Abdulmunem R.

    2015-04-01

    This work is devoted to improving the electrical efficiency by reducing the rate of thermal energy of a photovoltaic/thermal system (PV/T).This is achieved by design cooling technique which consists of a heat exchanger and water circulating pipes placed at PV module rear surface to solve the problem of the high heat stored inside the PV cells during the operation. An experimental rig is designed to investigate and evaluate PV module performance with the proposed cooling technique. This cooling technique is the first work in Iraq to dissipate the heat from PV module. The experimental results indicated that due to the heat loss by convection between water and the PV panel's upper surface, an increase of output power is achieved. It was found that without active cooling, the temperature of the PV module was high and solar cells could only achieve a conversion efficiency of about 8%. However, when the PV module was operated under active water cooling condition, the temperature was dropped from 76.8°C without cooling to 70.1°C with active cooling. This temperature dropping led to increase in the electrical efficiency of solar panel to 9.8% at optimum mass flow rate (0.2L/s) and thermal efficiency to (12.3%).

  8. Cellular Phone Towers

    MedlinePlus

    ... the call. How are people exposed to the energy from cellular phone towers? As people use cell ... where people can be exposed to them. The energy from a cellular phone tower antenna, like that ...

  9. Solar Heating and Cooling Experiment for a School in Atlanta. Performance Report.

    ERIC Educational Resources Information Center

    Westinghouse Electric Corp., Falls Church, VA.

    This report documents the performance and conclusions of a 13-month period of monitoring the performance of the experimental solar heating and cooling system installed in the George A. Towns Elementary School, Atlanta, Georgia. The objectives of the project were to (1) make a significant contribution to solar design, technology, and acceptability;…

  10. An analytical model for predicting the aerodynamic performance of a turbine cascade with film cooling

    NASA Technical Reports Server (NTRS)

    Mcfarland, E. R.; Tabakoff, W.

    1977-01-01

    Various analytical approaches to predicting the performance of film cooled turbine blades are reviewed. A two-dimensional cascade flow solution is developed for calculating the effects of the coolant injection on the total flow field. This solution is used with an available analytical performance predicting method to provide an improved method. Comparisons are made with experimental data and other analytical results.

  11. Advanced multistage turbine blade aerodynamics, performance, cooling, and heat transfer

    SciTech Connect

    Fleeter, S.; Lawless, P.B.

    1995-12-31

    The gas turbine has the potential for power production at the highest possible efficiency. The challenge is to ensure that gas turbines operate at the optimum efficiency so as to use the least fuel and produce minimum emissions. A key component to meeting this challenge is the turbine. Turbine performance, both aerodynamics and heat transfer, is one of the barrier advanced gas turbine development technologies. This is a result of the complex, highly three-dimensional and unsteady flow phenomena in the turbine. Improved turbine aerodynamic performance has been achieved with three-dimensional highly-loaded airfoil designs, accomplished utilizing Euler or Navier-Stokes Computational Fluid Dynamics (CFD) codes. These design codes consider steady flow through isolated blade rows. Thus they do not account for unsteady flow effects. However, unsteady flow effects have a significant impact on performance. Also, CFD codes predict the complete flow field. The experimental verification of these codes has traditionally been accomplished with point data - not corresponding plane field measurements. Thus, although advanced CFD predictions of the highly complex and three-dimensional turbine flow fields are available, corresponding data are not. To improve the design capability for high temperature turbines, a detailed understanding of the highly unsteady and three-dimensional flow through multi-stage turbines is necessary. Thus, unique data are required which quantify the unsteady three-dimensional flow through multi-stage turbine blade rows, including the effect of the film coolant flow. Also, as design CFD codes do not account for unsteady flow effects, the next logical challenge and the current thrust in CFD code development is multiple-stage analyses that account for the interactions between neighboring blade rows. Again, to verify and or direct the development of these advanced codes, complete three-dimensional unsteady flow field data are needed.

  12. Advanced multistage turbine blade aerodynamics, performance, cooling, and heat transfer

    SciTech Connect

    Fleeter, S.; Lawless, P.B.

    1995-10-01

    The gas turbine has the potential for power production at the highest possible efficiency. The challenge is to ensure that gas turbines operate at the optimum efficiency so as to use the least fuel and produce minimum emissions. A key component to meeting this challenge is the turbine. Turbine performance, both aerodynamics and heat transfer, is one of the barrier advanced gas turbine development technologies. This is a result of the complex, highly three-dimensional and unsteady flow phenomena in the turbine. Improved turbine aerodynamic performance has been achieved with three-dimensional highly-loaded airfoil designs, accomplished utilizing Euler or Navier-Stokes Computational Fluid Dynamics (CFD) codes. These design codes consider steady flow through isolated blade rows. Thus they do not account for unsteady flow effects. However, unsteady flow effects have a significant impact on performance. Also, CFD codes predict the complete flow field. The experimental verification of these codes has traditionally been accomplished with point data - not corresponding plane field measurements. Thus, although advanced CFD predictions of the highly complex and three-dimensional turbine flow fields are available, corresponding data are not. To improve the design capability for high temperature turbines, a detailed understanding of the highly unsteady and three-dimensional flow through multi-stage turbines is necessary. Thus, unique data are required which quantify the unsteady three-dimensional flow through multi-stage turbine blade rows, including the effect of the film coolant flow. This requires experiments in appropriate research facilities in which complete flow field data, not only point measurements, are obtained and analyzed. Also, as design CFD codes do not account for unsteady flow effects, the next logical challenge and the current thrust in CFD code development is multiple-stage analyses that account for the interactions between neighboring blade rows.

  13. Performance of evacuated tubular solar collectors in a residential heating and cooling system

    NASA Astrophysics Data System (ADS)

    Duff, W. S.; Loef, G. O. G.

    1981-03-01

    Operation of CSU Solar House I during the heating season of 1978-1979 and during the 1979 cooling season is discussed. The systems comprised an experimental evacuated tubular solar collector, a nonfreezing aqueous collection medium, heat exchange to an insulated conventional vertical cylindrical storage tank and to a built up rectangular insulated storage tank, heating of circulating air by solar heated water and by electric auxiliary in an off peak heat storage unit, space cooling by lithium bromide absorption chiller, and service water heating by solar exchange and electric auxiliary. The system is compared with CSU Solar Houses I, II and III. The experimental collector provides solar heating and cooling with minimum operational problems. Improved performance, particularly for cooling, resulted from the use of a very well insulated heat storage tank. Day time electric auxiliary heating is avoided by use of off peak electric heat storage.

  14. Effect of wearing an ice cooling jacket on repeat sprint performance in warm/humid conditions

    PubMed Central

    Duffield, R; Dawson, B; Bishop, D; Fitzsimons, M; Lawrence, S

    2003-01-01

    Objective: To examine the effect of cooling the skin with an ice jacket before and between exercise bouts (to simulate quarter and half time breaks) on prolonged repeat sprint exercise performance in warm/humid conditions. Methods: After an initial familiarisation session, seven trained male hockey players performed two testing sessions (seven days apart), comprising an 80 minute intermittent, repeat sprint cycling exercise protocol inside a climate chamber set at 30°C and 60% relative humidity. On one occasion a skin cooling procedure was implemented (in random counterbalanced order), with subjects wearing an ice cooling jacket both before (for five minutes) and in the recovery periods (2 x 5 min and 1 x 10 min) during the test. Measures of performance (work done and power output on each sprint), heart rates, blood lactate concentrations, core (rectal) and skin temperatures, sweat loss, perceived exertion, and ratings of thirst, thermal discomfort, and fatigue were obtained in both trials. Results: In the cooling condition, chest (torso) skin temperature, thermal discomfort, and rating of thirst were all significantly lower (p<0.05), but no significant difference (p>0.05) was observed between conditions for measures of work done, power output, heart rate, blood lactate concentration, core or mean skin temperature, perceived exertion, sweat loss, or ratings of fatigue. However, high effect sizes indicated trends to lowered lactate concentrations, sweat loss, and mean skin temperatures in the cooling condition. Conclusions: The intermittent use of an ice cooling jacket, both before and during a repeat sprint cycling protocol in warm/humid conditions, did not improve physical performance, although the perception of thermal load was reduced. Longer periods of cooling both before and during exercise (to lower mean skin temperature by a greater degree than observed here) may be necessary to produce such a change. PMID:12663361

  15. Cool running: locomotor performance at low body temperature in mammals.

    PubMed

    Rojas, A Daniella; Körtner, Gerhard; Geiser, Fritz

    2012-10-23

    Mammalian torpor saves enormous amounts of energy, but a widely assumed cost of torpor is immobility and therefore vulnerability to predators. Contrary to this assumption, some small marsupial mammals in the wild move while torpid at low body temperatures to basking sites, thereby minimizing energy expenditure during arousal. Hence, we quantified how mammalian locomotor performance is affected by body temperature. The three small marsupial species tested, known to use torpor and basking in the wild, could move while torpid at body temperatures as low as 14.8-17.9°C. Speed was a sigmoid function of body temperature, but body temperature effects on running speed were greater than those in an ectothermic lizard used for comparison. We provide the first quantitative data of movement at low body temperature in mammals, which have survival implications for wild heterothermic mammals, as directional movement at low body temperature permits both basking and predator avoidance.

  16. Flow and Thermal Performance of a Water-Cooled Periodic Transversal Elliptical Microchannel Heat Sink for Chip Cooling.

    PubMed

    Wei, Bo; Yang, Mo; Wang, Zhiyun; Xu, Hongtao; Zhang, Yuwen

    2015-04-01

    Flow and thermal performance of transversal elliptical microchannels were investigated as a passive scheme to enhance the heat transfer performance of laminar fluid flow. The periodic transversal elliptical micro-channel is designed and its pressure drop and heat transfer characteristics in laminar flow are numerically investigated. Based on the comparison with a conventional straight micro- channel having rectangular cross section, it is found that periodic transversal elliptical microchannel not only has great potential to reduce pressure drop but also dramatically enhances heat transfer performance. In addition, when the Reynolds number equals to 192, the pressure drop of the transversal elliptical channel is 36.5% lower than that of the straight channel, while the average Nusselt number is 72.8% higher; this indicates that the overall thermal performance of the periodic transversal elliptical microchannel is superior to the conventional straight microchannel. It is suggested that such transversal elliptical microchannel are attractive candidates for cooling future electronic chips effectively with much lower pressure drop. PMID:26353536

  17. Geology of Devils Tower National Monument, Wyoming

    USGS Publications Warehouse

    Robinson, Charles Sherwood

    1956-01-01

    Devils Tower is a steep-sided mass of igneous rock that rises above the surrounding hills and the valley of the Belle Fourche River in Crook County, Wyo. It is composed of a crystalline rock, classified as phonolite porphyry, that when fresh is gray but which weathers to green or brown. Vertical joints divide the rock mass into polygonal columns that extend from just above the base to the top of the Tower. The hills in the vicinity and at the base of the Tower are composed of red, yellow, green, or gray sedimentary rocks that consist of sandstone, shale, or gypsum. These rocks, in aggregate about 400 feet thick, include, from oldest to youngest, the upper part of the Spearfish formation, of Triassic age, the Gypsum Spring formation, of Middle Jurassic age, and the Sundance formation, of Late Jurassic age. The Sundance formation consists of the Stockade Beaver shale member, the Hulett sandstone member, the Lak member, and the Redwater shale member. The formations have been only slightly deformed by faulting and folding. Within 2,000 to 3.000 feet of the Tower, the strata for the most part dip at 3 deg - 5 deg towards the Tower. Beyond this distance, they dip at 2 deg - 5 deg from the Tower. The Tower is believed to have been formed by the intrusion of magma into the sedimentary rocks, and the shape of the igneous mass formed by the cooled magma is believed to have been essentially the same as the Tower today. Devils Tower owes its impressiveness to its resistance to erosion as compared with the surrounding sedimentary rocks, and to the contrast of the somber color of the igneous column to the brightly colored bands of sedimentary rocks.

  18. Performance and economic enhancement of cogeneration gas turbines through compressor inlet air cooling

    NASA Astrophysics Data System (ADS)

    Delucia, M.; Bronconi, R.; Carnevale, E.

    1994-04-01

    Gas turbine air cooling systems serve to raise performance to peak power levels during the hot months when high atmospheric temperatures cause reductions in net power output. This work describes the technical and economic advantages of providing a compressor inlet air cooling system to increase the gas turbine's power rating and reduce its heat rate. The pros and cons of state-of-the-art cooling technologies, i.e., absorption and compression refrigeration, with and without thermal energy storage, were examined in order to select the most suitable cooling solution. Heavy-duty gas turbine cogeneration systems with and without absorption units were modeled, as well as various industrial sectors, i.e., paper and pulp, pharmaceuticals, food processing, textiles, tanning, and building materials. The ambient temperature variations were modeled so the effects of climate could be accounted for in the simulation. The results validated the advantages of gas turbine cogeneration with absorption air cooling as compared to other systems without air cooling.

  19. Effects of anti-recirculation ring on performance of an automotive cooling fan

    NASA Astrophysics Data System (ADS)

    Chen, Q. G.; Zhang, Y. C.; Li, F.; Kong, X. Z.; Luan, X. H.

    2013-12-01

    An investigation has been conducted to evaluate the effects of anti-recirculation ring on performance of automotive axial flow cooling fan by CFD simulation. In order to reduce the element size and save computing time, periodic boundary condition and single flow channel has been applied to the simulation. The grid is composed of tetrahedral mesh and hexahedral mesh. The SST k - ω turbulence model and standard wall function method have been used. CFD results show that optimal design of pressure loss anti-recirculation ring can not only increase P-Q performance and aerodynamic efficiency, but also can improve the pressure distribution on fan tip which can reduce the axial deformation of cooling fan. So it can be proved that good design of anti-recirculation ring will not increase the total axial size of an axial cooling fan.

  20. Experimental study of spray cooling performance on micro-porous coated surfaces

    NASA Astrophysics Data System (ADS)

    Kim, Yoon-Ho; Choi, Chihwan; Lee, Kyu-Jung; Han, Donghyouck

    2009-08-01

    Experiments on evaporative spray cooling of flat heaters with plain and micro-porous coated surfaces were performed in this study. Micro-porous coated surfaces were made by using the DOM [Diamond particle, Omegabond 101, Methyl-Ethyl-Keton] coating method. In pure air-jet cooling, micro-porous coating did not show heat transfer improvement over plain surface. In spray cooling, however, three different flow patterns (complete wetting, evaporative wetting and dryout) were observed on both plain and micro-porous coated surfaces. The effects of various operating conditions, such as water flow rate, particle size, and coating thickness on the micro-porous coated surface were investigated. It was found that the level of surface wetting was an important factor in determining the performance of spray cooling. The level of surface wetting depended on the balance between the amount of liquid absorbed by capillary force over porosity and the amount of liquid evaporated. A micro-porous coated surface has a very high cooling capacity, especially in the evaporative wetting zone. The liquid flow rate and coating thickness are significant factors in the evaporative wetting zone, but are not in the complete wetting zone and the dryout zone.

  1. Performance criteria for solar heating and cooling systems in residential buildings

    NASA Astrophysics Data System (ADS)

    1982-09-01

    This performance criteria, developed for the Department of Housing and Urban Development, is a baseline document for criteria and standards for the design, development, technical evaluation, and procurement of solar heating and cooling systems for residential buildings in accordance with the requirements of Section 8 of Public Law 93-409, the Solar Heating and Cooling Demonstration Act of 1974. The document is intended to establish minimum levels of performance with regard to health and safety and the various aspects of technical performance. The criteria for health and safety put primary emphasis on compliance with existing codes and standards. The criteria on thermal and mechanical performance, durability/reliability and operation/servicing present performance requirements considered to be representative of acceptable levels.

  2. Cooled perch effects on performance and well-being traits in caged White Leghorn hens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We assessed the effects of chilled water cooling perches on hen performance, feather condition, foot health, and physiological and behavioral parameters during the 2013 summer with a 4-h acute heating episode. White Leghorn pullets at 16 wk of age were randomly assigned to 18 cages arranged into 3 b...

  3. Performance of the Upgraded Stacktail Momentum Cooling System in the Fermilab Antiproton Source

    SciTech Connect

    Pasquinelli, Ralph J.; McGinnis, David; /Fermilab

    1992-01-01

    Major changes in the Stacktail Momentum Stochastic Cooling system have resulted in an improved stacking rate as well as the capability to stack larger quantities of antiprotons. Both these effects result in higher initial and integrated luminosity for colliding beam physics. An overview of the changes and actual system performance is presented.

  4. Ultimate Heat Sink Thermal Performance and Water Utilization: Measurements on Cooling and Spray Ponds

    SciTech Connect

    Athey, G. F.; Hadlock, R. K.; Abbey, O. B.

    1982-02-01

    A data acquisition research program, entitled "Ultimate Heat Sink Performance Field Experiments," has been brought to completion. The primary objective is to obtain the requisite data to characterize thermal performance and water utilization for cooling ponds and spray ponds at elevated temperature. Such data are useful for modeling purposes, but the work reported here does not contain modeling efforts within its scope. The water bodies which have been studied are indicative of nuclear reactor ultimate heat sinks, components of emergency core cooling systems. The data reflect thermal performance and water utilization for meteorological and solar influences which are representative of worst-case combinations of conditions. Constructed water retention ponds, provided with absolute seals against seepage, have been chosen as facilities for the measurement programs; the first pond was located at Raft River, Idaho, and the second at East Mesa, California. The data illustrate and describe, for both cooling ponds and spray ponds, thermal performance and water utilization as the ponds cool from an initially elevated temperature. To obtain the initial elevated temperature, it has been convenient to conduct the measurements at geothermal sites having large supplies and delivery rates of hot geothermal fluid. The data are described and discussed in the text, and presented in the form of data volumes as appendices.

  5. Analysis of cooling limitations and effect of engine-cooling improvements on level-flight cruising performance of four-engine heavy bomber

    NASA Technical Reports Server (NTRS)

    Marble, Frank E; Miller, Marlon A; Bell, E Barton

    1946-01-01

    The NACA has developed means, including an injection impeller and ducted head baffles, to improve the cooling characteristics of the 3350-cubic-inch-displacement radial engines installed in a four-engine heavy bomber. The improvements afforded proper cooling of the rear-row exhaust-valve seats for a wide range of cowl-flap angles, mixture strengths, and airplane speeds. The results of flight tests with this airplane are used as a basis for a study to determine the manner and the extent to which the airplane performance was limited by engine cooling. By means of this analysis for both the standard airplane and the airplane with engine-cooling modifications, comparison of the specific range at particular conditions and comparison of the cruising-performance limitations was made.

  6. Cost and performance goal methodology for active solar-cooling systems

    NASA Astrophysics Data System (ADS)

    Warren, M. L.; Wahlig, M. A.

    1982-02-01

    Economic and thermal performance analyses of typical residential and commercial active solar cooling systems are used to determine cost goals for systems to be installed between the years 1986 and 2000. Market studies indicate a relationship between market penetration (percent of market captured) and payback period for heating, ventilating, and air conditioning systems. Using reasonable values for fuel escalation and inflation rates, the payback period is related to the expected real return on investment. Postulating commercial introduction of solar cooling systems in 1986 with the market share increasing to 20% by the year 2000, payback and return on investment goals for cooling systems as a function of year of purchase are established. Using the results of systems analysis of representative 3 ton solar residential cooling/heating systems and 25 ton commercial solar cooling systems for four different cities (Ft. Worth, Phoenix, Miami, and Washington, DC), the return on investment goals are used to calculate the 20 year present value of energy savings of the solar energy systems.

  7. Development of a model to simulate the performance of hydronic radiant cooling ceilings

    SciTech Connect

    Stetiu, C.; Feustel, H.E.

    1995-06-01

    A significant amount of the electrical energy used to cool non-residential buildings equipped with all-air systems is drawn by the fans that transport the cool air through the thermal distribution system. Hydronic radiant cooling systems have the potential to reduce the amount of air transported through the building by separating the tasks of ventilation and thermal conditioning. Because of the physical properties of water, hydronic radiant cooling systems can transport a given amount of thermal energy using less than 5170 of the otherwise necessary fan energy. This improvement alone significantly reduces the energy consumption and peak power requirement of the air conditioning system. Hydronic radiant cooling systems have been used for more than 30 years in hospital rooms to provide a draft-free, thermally stable environment. The energy savings and peak-load characteristics of these systems have not yet been analyzed systematically. Moreover, adequate guidelines for design and control of these systems do not exist. This has prevented their widespread application to other building types. The evaluation of the theoretical performance of hydronic systems could be made most conveniently by computer models. Energy analysis programs such as DOE-2 do not have the capability to simulate hydronic radiant systems yet. In this paper the development of a model that can simulate accurately the dynamic performance of hydronic radiant cooling systems is described. The model is able to calculate loads, heat extraction rates, room air temperature and room surface temperature distributions, and can be used to evaluate issues such as thermal comfort, controls, system sizing, system configuration and dynamic response. The model was created with the Simulation Problem Analysis and Research Kernel (SPARK) developed at the Lawrence Berkeley Laboratory, which provides a methodology for describing and solving the dynamic, non-linear equations that correspond to complex physical systems.

  8. Effects of liquid cooling garments on recovery and performance time in individuals performing strenuous work wearing a firefighter ensemble.

    PubMed

    Kim, Jung-Hyun; Coca, Aitor; Williams, W Jon; Roberge, Raymond J

    2011-07-01

    This study investigated the effects of body cooling using liquid cooling garments (LCG) on performance time (PT) and recovery in individuals wearing a fully equipped prototype firefighter ensemble (PFE) incorporating a self-contained breathing apparatus (SCBA). Six healthy male participants (three firefighters and three non-firefighters) completed six experimental sessions in an environmental chamber (35°C, 50% relative humidity), consisting of three stages of 15 min exercise at 75% VO2max, and 10 min rest following each exercise stage. During each session, one of the following six conditions was administered in a randomized order: control (no cooling, CON); air ventilation of exhaust SCBA gases rerouted into the PFE (AV); top cooling garment (TCG); TCG combined with AV (TCG+AV); a shortened whole body cooling garment (SCG), and SCG combined with AV (SCG+AV). Results showed that total PT completed was longer under SCG and SCG+AV compared with CON, AV, TCG, and TCG+AV (p<0.01). Magnitude of core temperature (Tc) elevation was significantly decreased when SCG was utilized (p<0.01), and heart rate recovery rate (10 min) was enhanced under SCG, SCG+AV, TCG, and TCG+AV compared with CON (p<0.05). Estimated Esw rate (kg·h(-1)) was the greatest in CON, 1.62 (0.37), and the least in SCG+AV 0.98 (0.44): (descending order: CON>AV>TCG=TCG+AV>SCG>SCG+AV) without a statistical difference between the conditions (p<0.05). Results of the present study suggest that the application of LCG underneath the PFE significantly improves the recovery during a short period of rest and prolongs performance time in subsequent bouts of exercise. LCG also appears to be an effective method for body cooling that promotes heat dissipation during uncompensable heat stress.

  9. Cool and Quiet: Partnering to Enhance the Aerodynamic and Acoustic Performance of Installed Electronics Cooling Fans: A White Paper

    NASA Technical Reports Server (NTRS)

    Koch, L. Danielle; VanZante, Dale E.

    2006-01-01

    Breathtaking images of distant planets. Spacewalks to repair a telescope in orbit. Footprints on the moon. The awesome is made possible by the mundane. Every achievement in space exploration has relied on solid, methodical advances in engineering. Space exploration fuels economic development like no other endeavor can. But which advances will make their way into our homes and businesses? And how long will it take? Answers to these questions are dependent upon industrial involvement in government sponsored research initiatives, market demands, and timing. Recognizing an opportunity is half the battle. This proposal describes the framework for a collaborative research program aimed at improving the aerodynamic and acoustic performance of electronics cooling fans. At its best, the program would involve NASA and academic researchers, as well as corporate researchers representing the Information Technology (IT) and fan manufacturing industries. The momentum of space exploration, the expertise resultant from the nation's substantial investment in turbofan noise reduction research, and the competitiveness of the IT industry are intended to be catalysts of innovation.

  10. Steam-Electric Power-Plant-Cooling Handbook

    SciTech Connect

    Sonnichsen, J.C.; Carlson, H.A.; Charles, P.D.; Jacobson, L.D.; Tadlock, L.A.

    1982-02-01

    The Steam-Electric Power Plant Cooling Handbook provides summary data on steam-electric power plant capacity, generation and number of plants for each cooling means, by Electric Regions, Water Resource Regions and National Electric Reliability Council Areas. Water consumption by once-through cooling, cooling ponds and wet evaporative towers is discussed and a methodology for computation of water consumption is provided for a typical steam-electric plant which uses a wet evaporative tower or cooling pond for cooling.

  11. The Tower Shielding Facility: Its glorious past

    SciTech Connect

    Muckenthaler, F.J.

    1997-05-07

    The Tower Shielding Facility (TSF) is the only reactor facility in the US that was designed and built for radiation-shielding studies in which both the reactor source and shield samples could be raised into the air to allow measurements to be made without interference from ground scattering or other spurious effects. The TSF proved its usefulness as many different programs were successfully completed. It became active in work for the Defense Atomic Support Agency (DASA) Space Nuclear Auxiliary Power, Defense Nuclear Agency, Liquid Metal Fast Breeder Reactor Program, the Gas-Cooled and High-Temperature Gas-Cooled Reactor programs, and the Japanese-American Shielding Program of Experimental Research, just to mention a few of the more extensive ones. The history of the TSF as presented in this report describes the various experiments that were performed using the different reactors. The experiments are categorized as to the programs which they supported and placed in corresponding chapters. The experiments are described in modest detail, along with their purpose when appropriate. Discussion of the results is minimal, but references are given to more extensive topical reports.

  12. Valve timing effect on the cooling performance of a 4 K pulse tube cooler

    NASA Astrophysics Data System (ADS)

    Qiu, L. M.; Thummes, G.

    2002-05-01

    Generally, a compressor together with a rotary valve system generates the pressure oscillation in GM-type cryocoolers. The timing of the rotary valve, which is one of the key operating parameters for cryocoolers, determines the relationship between intake and exhaust processes. A systematic investigation of valve timing effects on cooling performance of a two-stage 4 K pulse tube cooler (PTC) is reported. The experiments show that the optimization of valve timing can considerably improve the cooling performance for both stages. For the same PTC, a performance comparison for operation on different compressors with various input powers ranging from 0.5 to 6.0 kW is also presented.

  13. Passive solar/Earth sheltered office/dormitory cooling season thermal performance

    NASA Astrophysics Data System (ADS)

    Christian, J.

    1984-06-01

    Continuous detailed hourly thermal performance measurements were taken since February 1982 in and around an occupied, underground, 4000 ft(2) office/dormitory building at the Oak Ridge National Laboratory in Oak Ridge, Tennessee. This building has a number of energy saving features which were analyzed relative to their performance in a southeastern US climate and with respect to overall commercial building performance. Cooling season performance is documented, as well as effects of earth constact, interior thermal mass, an economizer cycle and interface of an efficient building envelope with a central three-ton heat pump. The Joint Institute Dormitory obtains a cooling energy savings of about 30% compared with an energy-efficient, above-grade structure and has the potential to save as much as 50%. The proper instllation of the overhand, interior thermal mass, massive supply duct system, and earth contact team up to prevent summertime overheating. From May through September, this building cost a total of $300 (at 5.7) cents/kWh) to cool and ventilate 24 hours per day. Besides thermal performance of the building envelope, extensive comfort data was taken illustrating that at least 90% of the occupants are comfortable all of the time according to the PMV measurements.

  14. Cross-sectional versus longitudinal age gradients of tower of Hanoi performance: the role of practice effects and cohort differences in education.

    PubMed

    Rönnlund, Michael; Lövdén, Martin; Nilsson, Lars-Göran

    2008-01-01

    We examined 5-year longitudinal changes in Tower of Hanoi (TOH) performance in a population-based sample of adults (35-85 years initially; n = 1480). An age-matched sample (n = 433) was included to estimate practice effects. The longitudinal age gradients differed substantially from the cross-sectional age gradients. This was the case even when practice effects, that were substantial in magnitude across the young/middle-aged groups, were controlled for. Instead of a continuous age-related deficit in performance from 35 and onwards, longitudinal data showed slowing of performance and increases of illegal moves past age 65. Cohort-related differences in educational attainment did not account for this discrepancy. Further analyses revealed a positive relation between practice-related gains and explicit memory of having performed the task at the first test occasion and a positive association between latent changes in TOH and Block Design, in line with cross-sectional findings. In conclusion, the results demonstrate a pattern of age-related changes indicating a late-onset decline of TOH performance and underscore the need to control for retest effects in longitudinal aging research. PMID:17924234

  15. Study on Cooling Performance of Stirling Cycle Machine wiht New Regenerator Matrix

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru; Kitahama, Dai; Takeuchi, Takuro; Matsuguchi, Atsushi; Tsuruno, Seizo

    In order to develop Stirling cycle machines with high efficiency, suitable regenerator for each machine must be designed. To realize the flexibility of design and to improve the performance of regenerator, a new matrix, mesh sheet was proposed. It is a plate type with electrically etched holes. Each small hole is connected with neighboring holes by grooves on the plate. The performance test of cooling mode was carried out with a 3-kW Stirling engine in order to measure its cooling performance. Three types of the mesh sheet were developed and two of them were respectively stacked to install in the machine. Also, the pressure and regenerator losses were compared with conventional stacked wire gauzes and the mesh sheets. From the results, it was clarified that the performance of the cooling mode was improved about 5 to 40 % by the mesh sheet. In this paper, the relation between the dimensions of the mesh sheet, the pressure and regenerator losses were also clarified.

  16. Variable Gravity Effects on the Cooling Performance of a Single Phase Confined Spray

    NASA Technical Reports Server (NTRS)

    Michalak, Travis; Yerkes, Kirk; Baysinger, Karri; McQuillen, John

    2005-01-01

    The objective of this paper is to discuss the testing of a spray cooling experiment designed to be flown on NASA's KC-135 Reduced Gravity Testing Platform. Spray cooling is an example of a thermal management technique that may be utilized in high flux heat acquisition and high thermal energy transport concepts. Many researchers have investigated the utility of spray cooling for the thermal management of devices generating high heat fluxes. However, there has been little research addressing the physics and ultimate performance of spray cooling in a variable gravity environment. An experimental package, consisting of a spray chamber coupled to a fluid delivery loop system, was fabricated for variable gravity flight tests. The spray chamber contains two opposing nozzles spraying on target Indium Tin Oxide (ITO) heaters. These heaters are mounted on glass pedestals, which are part of a sump system to remove unconstrained liquid from the test chamber. Liquid is collected in the sumps and returned to the fluid delivery loop. Thermocouples mounted in and around the pedestals are used to determine both the heat loss through the underside of the IT0 heater and the heat extracted by the spray. A series of flight tests were carried out aboard the KC-135, utilizing the ability of the aircraft to produce various gravity conditions. During the flight tests, for a fixed flow rate, heat input was varied at 20, 30, 50, and 80W with variable gravities of 0.01, 0.16, 0.36, and 1.8g. Flight test data was compared to terrestrial baseline data in addition to analytical and numerical solutions to evaluate the heat transfer in the heater and support structure . There were significant differences observed in the spray cooling performance as a result of variable gravity conditions and heat inputs. In general, the Nussult number at the heater surface was found to increase with decreasing gravity conditions for heat loads greater than 30W.

  17. Experiment attributes to establish tube with twisted tape insert performance cooling plasma facing components

    DOE PAGES

    Clark, Emily; Ramirez, Emilio; Ruggles, Art E.; Griffard, Cory

    2015-08-18

    The modeling capability for tubes with twisted tape inserts is reviewed with reference to the application of cooling plasma facing components in magnetic confinement fusion devices. The history of experiments examining the cooling performance of tubes with twisted tape inserts is reviewed with emphasis on the manner of heating, flow stability limits and the details of the test section and fluid delivery system. Models for heat transfer, burnout, and onset of net vapor generation in straight tube flows and tube with twisted tape are compared. As a result, the gaps in knowledge required to establish performance limits of the plasmamore » facing components are identified and attributes of an experiment to close those gaps are presented.« less

  18. Experiment attributes to establish tube with twisted tape insert performance cooling plasma facing components

    SciTech Connect

    Clark, Emily; Ramirez, Emilio; Ruggles, Art E.; Griffard, Cory

    2015-08-18

    The modeling capability for tubes with twisted tape inserts is reviewed with reference to the application of cooling plasma facing components in magnetic confinement fusion devices. The history of experiments examining the cooling performance of tubes with twisted tape inserts is reviewed with emphasis on the manner of heating, flow stability limits and the details of the test section and fluid delivery system. Models for heat transfer, burnout, and onset of net vapor generation in straight tube flows and tube with twisted tape are compared. As a result, the gaps in knowledge required to establish performance limits of the plasma facing components are identified and attributes of an experiment to close those gaps are presented.

  19. Performance optimization considerations for thermionic fuel elements in a heat pipe cooled thermionic reactor

    NASA Astrophysics Data System (ADS)

    Bellis, Elizabeth A.

    1992-01-01

    A heat pipe-cooled, in-core thermionic (HPTI) reactor design has been proposed in support of the Air Force Thermionic Space Nuclear Power Program. As part of this design, the performance of the power conversion system has been characterized. This paper focuses on the performance optimization studies carried out of a thermionic fuel element (TFE) which will be used in a reactor design capable of producing 40 kWe over a 10 year operating life. The technical approach to the optimization studies closely couples converter lifetime constraints with converter performance to produce the best possible design choice.

  20. Confusion at the Tower

    ERIC Educational Resources Information Center

    Li, Loretta F.

    2014-01-01

    This study will explore the omission of the Tower of Babel narrative from middle and secondary school world history, world studies, and world geography textbooks and will consider what might be learned from inclusion of the story in the curriculum. A total of 17 textbooks are analyzed. The Tower of Babel narrative is examined within the context of…

  1. Leaning Tower of PESA

    ERIC Educational Resources Information Center

    Clark, John

    2009-01-01

    There is a certain similarity between the Philosophy of Education Society of Australasia (PESA) and the leaning tower of Pisa. Both have a certain presence on the landscape: the tower has a commanding appearance on the Italian countryside while PESA has left its mark on the academic fabric of Australasia. Both are much loved: Pisa by visiting…

  2. Drop Tower Physics

    ERIC Educational Resources Information Center

    Dittrich, William A.

    2014-01-01

    The drop towers of yesteryear were used to make lead shot for muskets, as described in "The Physics Teacher" in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at…

  3. Predicts the Steady-State Heating and Cooling Performance of Electric Heat Pump

    1993-01-13

    Oak Ridge National Laboratory (ORNL) is a leader in the development of analytical tools for the design of electrically driven, air-to-air heat pumps. Foremost among these tools is the ORNL Heat Pump Design Model, which can be used to predict the steady-state heating and cooling performance of an electrically driven, air-source heat pump. This version is three to five times faster than the earlier version, easier to use and more versatile.

  4. Experimental study on the operational and the cooling performance of the APR+ passive auxiliary feedwater system

    SciTech Connect

    Kang, K. H.; Bae, B. U.; Kim, S.; Cho, Y. J.; Park, Y. S.; Kim, B. D.

    2012-07-01

    The passive auxiliary feedwater system (PAFS) is one of the advanced safety features adopted in the APR+ which is intended to completely replace the conventional active auxiliary feedwater system. The PAFS cools down the steam generator secondary side and eventually removes the decay heat from the reactor core by introducing a natural driving force mechanism; i.e., condensing steam in nearly-horizontal U-tubes submerged inside the passive condensation cooling tank (PCCT). With an aim of validating the cooling and operational performance of the PAFS, the separate effect test, PASCAL (PAFS Condensing Heat Removal Assessment Loop), is being performed to experimentally investigate the condensation heat transfer and natural convection phenomena in the PAFS. A single nearly-horizontal U-tube whose dimension is same as the prototypic U-tube of the APR+ PAFS is simulated in the PASCAL test. By performing the PASCAL test, the major thermal-hydraulic parameters such as local/overall heat transfer coefficients, fluid temperature inside the tube, wall temperature of the tube, and pool temperature distribution in the PCCT were produced not only to evaluate the current condensation heat transfer model but also to present database for the safety analysis related with the PAFS. (authors)

  5. Wind tower service lift

    DOEpatents

    Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

    2011-09-13

    An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

  6. Solar Heating and Cooling for a Controls Manufacturing Plant Lumberton, New Jersey

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Comprehensive report documents computer-controlled system which has separate solar-collector and cooling-tower areas located away from building and is completely computer controlled. System description, test data, major problems and resolution, performance, operation and maintenance, manufacturer's literature and drawing comprise part of 257-page report.

  7. 24-gauge ultrafine cryoprobe with diameter of 550 μm and its cooling performance.

    PubMed

    Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-12-01

    This paper describes the development of a novel cryoprobe with the same size as a 24-gauge injection needle and the evaluation of its cooling performance. This ultrafine cryoprobe was designed to reduce the invasiveness and extend application areas of cryosurgery. The ultrafine cryoprobe has a double-tube structure and consists of two stainless steel microtubes. The outer diameter of the cryoprobe is 550 μm, and the inner tube has a 70-μm inner diameter to depressurize the high-pressure refrigerant. By solving the bioheat transfer equation and considering freezing phenomena, the relationship between the size of the frozen region and the heat transfer coefficient of the refrigerant flow in an ultrafine cryoprobe was derived analytically. The results showed that the size of the frozen region is strongly affected by the heat transfer coefficient. A high heat transfer coefficient such as that of phase change heat transfer is required to generate a frozen region of sufficient size. In the experiment, trifluoromethane (HFC-23) was used as the refrigerant, and the cooling effects of the gas and liquid phase states at the inlet were evaluated. When the ultrafine cryoprobe was cooled using a liquid refrigerant, the surface temperature was approximately -50°C, and the temperature distribution on the surface was uniform for a thermally insulated condition. However, for the case with vaporized refrigerant, the temperature distribution was not uniform. Therefore, it was concluded that the cooling mechanism using liquid refrigerant was suitable for ultrafine cryoprobes. Furthermore, to simulate cryosurgery, a cooling experiment using hydrogel was conducted. The results showed that the surface temperature of the ultrafine cryoprobe reached -35°C and formed a frozen region with a radius of 4 mm in 4 min. These results indicate that the ultrafine cryoprobe can be applied in actual cryosurgeries for small affected areas. PMID:25305055

  8. 24-gauge ultrafine cryoprobe with diameter of 550 μm and its cooling performance.

    PubMed

    Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-12-01

    This paper describes the development of a novel cryoprobe with the same size as a 24-gauge injection needle and the evaluation of its cooling performance. This ultrafine cryoprobe was designed to reduce the invasiveness and extend application areas of cryosurgery. The ultrafine cryoprobe has a double-tube structure and consists of two stainless steel microtubes. The outer diameter of the cryoprobe is 550 μm, and the inner tube has a 70-μm inner diameter to depressurize the high-pressure refrigerant. By solving the bioheat transfer equation and considering freezing phenomena, the relationship between the size of the frozen region and the heat transfer coefficient of the refrigerant flow in an ultrafine cryoprobe was derived analytically. The results showed that the size of the frozen region is strongly affected by the heat transfer coefficient. A high heat transfer coefficient such as that of phase change heat transfer is required to generate a frozen region of sufficient size. In the experiment, trifluoromethane (HFC-23) was used as the refrigerant, and the cooling effects of the gas and liquid phase states at the inlet were evaluated. When the ultrafine cryoprobe was cooled using a liquid refrigerant, the surface temperature was approximately -50°C, and the temperature distribution on the surface was uniform for a thermally insulated condition. However, for the case with vaporized refrigerant, the temperature distribution was not uniform. Therefore, it was concluded that the cooling mechanism using liquid refrigerant was suitable for ultrafine cryoprobes. Furthermore, to simulate cryosurgery, a cooling experiment using hydrogel was conducted. The results showed that the surface temperature of the ultrafine cryoprobe reached -35°C and formed a frozen region with a radius of 4 mm in 4 min. These results indicate that the ultrafine cryoprobe can be applied in actual cryosurgeries for small affected areas.

  9. Performance of Introducing Outdoor Cold Air for Cooling a Plant Production System with Artificial Light.

    PubMed

    Wang, Jun; Tong, Yuxin; Yang, Qichang; Xin, Min

    2016-01-01

    The commercial use of a plant production system with artificial light (PPAL) is limited by its high initial construction and operation costs. The electric-energy consumed by heat pumps, applied mainly for cooling, accounts for 15-35% of the total electric-energy used in a PPAL. To reduce the electric-energy consumption, an air exchanger with low capacity (180 W) was used for cooling by introducing outdoor cold air. In this experiment, the indoor air temperature in two PPALs (floor area: 6.2 m(2) each) was maintained at 25 and 20°C during photoperiod and dark period, respectively, for lettuce production. A null CO2 balance enrichment method was used in both PPALs. In one PPAL (PPALe), an air exchanger (air flow rate: 250 m(3)·h(-1)) was used along with a heat pump (cooling capacity: 3.2 kW) to maintain the indoor air temperature at the set-point. The other PPAL (PPALc) with only a heat pump (cooling capacity: 3.2 kW) was used for reference. Effects of introducing outdoor cold air on energy use efficiency, coefficient of performance (COP), electric-energy consumption for cooling and growth of lettuce were investigated. The results show that: when the air temperature difference between indoor and outdoor ranged from 20.2 to 30.0°C: (1) the average energy use efficiency of the air exchanger was 2.8 and 3.4 times greater than the COP of the heat pumps in the PPALe and PPALc, respectively; (2) hourly electric-energy consumption for cooling in the PPALe reduced by 15.8-73.7% compared with that in the PPALc; (3) daily supply of CO2 in the PPALe reduced from 0.15 to 0.04 kg compared with that in the PPALc with the outdoor air temperature ranging from -5.6 to 2.7°C; (4) no significant difference in lettuce growth was observed in both PPALs. The results indicate that using air exchanger to introduce outdoor cold air should be considered as an effective way to reduce electric-energy consumption for cooling with little effects on plant growth in a PPAL. PMID:27066012

  10. Performance of Introducing Outdoor Cold Air for Cooling a Plant Production System with Artificial Light

    PubMed Central

    Wang, Jun; Tong, Yuxin; Yang, Qichang; Xin, Min

    2016-01-01

    The commercial use of a plant production system with artificial light (PPAL) is limited by its high initial construction and operation costs. The electric-energy consumed by heat pumps, applied mainly for cooling, accounts for 15–35% of the total electric-energy used in a PPAL. To reduce the electric-energy consumption, an air exchanger with low capacity (180 W) was used for cooling by introducing outdoor cold air. In this experiment, the indoor air temperature in two PPALs (floor area: 6.2 m2 each) was maintained at 25 and 20°C during photoperiod and dark period, respectively, for lettuce production. A null CO2 balance enrichment method was used in both PPALs. In one PPAL (PPALe), an air exchanger (air flow rate: 250 m3·h−1) was used along with a heat pump (cooling capacity: 3.2 kW) to maintain the indoor air temperature at the set-point. The other PPAL (PPALc) with only a heat pump (cooling capacity: 3.2 kW) was used for reference. Effects of introducing outdoor cold air on energy use efficiency, coefficient of performance (COP), electric-energy consumption for cooling and growth of lettuce were investigated. The results show that: when the air temperature difference between indoor and outdoor ranged from 20.2 to 30.0°C: (1) the average energy use efficiency of the air exchanger was 2.8 and 3.4 times greater than the COP of the heat pumps in the PPALe and PPALc, respectively; (2) hourly electric-energy consumption for cooling in the PPALe reduced by 15.8–73.7% compared with that in the PPALc; (3) daily supply of CO2 in the PPALe reduced from 0.15 to 0.04 kg compared with that in the PPALc with the outdoor air temperature ranging from −5.6 to 2.7°C; (4) no significant difference in lettuce growth was observed in both PPALs. The results indicate that using air exchanger to introduce outdoor cold air should be considered as an effective way to reduce electric-energy consumption for cooling with little effects on plant growth in a PPAL. PMID:27066012

  11. Thermal Performance Mapping of Direct Liquid Cooled 3d Chip Stacks

    NASA Astrophysics Data System (ADS)

    Geisler, Karl J. L.; Bar-Cohen, Avram

    Chip stacks are a crucial building block in advanced 3D microsystem architectures and can accommodate shorter interconnect distances between devices, leading to reduced power dissipation and improved electrical performance. Although enhanced conduction can serve to transfer the dissipated heat to the top and sides of the package and/or down to the underlying PCB, effective thermal management of stacked chips remains a most difficult challenge. Immersion cooling techniques, which provide convective and/or ebullient heat transfer, along with buoyant fluid flow, in the narrow gaps separating adjacent chips, are a most promising alternative to conduction cooling of threedimensional chip stacks. Application of the available theories, correlations, and experimental data are shown to reveal that passive immersion cooling--relying on natural convection and/or pool boiling--could provide the requisite thermal management capability for 3D chip stacks anticipated for use in much of the portable equipment category. Alternatively, pumped flow of dielectric liquids through the microgaps in 3D stacks, providing single phase and/or flow boiling heat absorption, could meet many of the most extreme thermal management requirements for high-performance 3D microsystems.

  12. Fuel performance models for high-temperature gas-cooled reactor core design

    SciTech Connect

    Stansfield, O.M.; Simon, W.A.; Baxter, A.M.

    1983-09-01

    Mechanistic fuel performance models are used in high-temperature gas-cooled reactor core design and licensing to predict failure and fission product release. Fuel particles manufactured with defective or missing SiC, IPyC, or fuel dispersion in the buffer fail at a level of less than 5 x 10/sup -4/ fraction. These failed particles primarily release metallic fission products because the OPyC remains intact on 90% of the particles and retains gaseous isotopes. The predicted failure of particles using performance models appears to be conservative relative to operating reactor experience.

  13. Monitoring of the performance of a solar heated and cooled apartment building

    NASA Astrophysics Data System (ADS)

    Vliet, G. C.; Srubar, R. L.

    1980-03-01

    An all electric apartment building in Texas was retrofitted for solar heating and cooling and hot water. The system consisted of an array of 1280 square feet of Northrup concentrating tracking collectors, a 5000 gallon hot water storage vessel, a 500 gallon chilled water storage vessel, a 25 ton Arkla Industries absorption chiller, and a two pipe hydronic air conditioning system. The solar air conditioning equipment was installed in parallel with the existing conventional electric heating and cooling system, and the solar domestic water heating served as preheat to the existing electric water heaters. The system was fully instrumented for monitoring. Detailed descriptions of the solar system, the performance monitoring system, and the data reduction processes are given.

  14. Thermal performance of a Concrete Cool Roof under different climatic conditions of Mexico

    SciTech Connect

    Hernández-Pérez, I.; Álvarez, G.; Gilbert, H.; Xamán, J.; Chávez, Y.; Shah, B.

    2014-11-27

    A cool roof is an ordinary roof with a reflective coating on the exterior surface which has a high solar reflectance and high thermal emittance. These properties let the roof keep a lower temperature than a standard roof under the same conditions. In this work, the thermal performance of a concrete roof with and without insulation and with two colors has been analyzed using the finite volume method. The boundary conditions of the external roof surface were taken from hourly averaged climatic data of four cities. For the internal surface, it is considered that the building is air-conditioned and the inside air has a constant temperature. The interior surface temperature and the heat flux rates into the roofs were obtained for two consecutive days in order to assess the benefits of a cool roofs in different climates.

  15. Thermal performance of a Concrete Cool Roof under different climatic conditions of Mexico

    DOE PAGES

    Hernández-Pérez, I.; Álvarez, G.; Gilbert, H.; Xamán, J.; Chávez, Y.; Shah, B.

    2014-11-27

    A cool roof is an ordinary roof with a reflective coating on the exterior surface which has a high solar reflectance and high thermal emittance. These properties let the roof keep a lower temperature than a standard roof under the same conditions. In this work, the thermal performance of a concrete roof with and without insulation and with two colors has been analyzed using the finite volume method. The boundary conditions of the external roof surface were taken from hourly averaged climatic data of four cities. For the internal surface, it is considered that the building is air-conditioned and themore » inside air has a constant temperature. The interior surface temperature and the heat flux rates into the roofs were obtained for two consecutive days in order to assess the benefits of a cool roofs in different climates.« less

  16. View of Nevada rim towers from Arizona side. Left tower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Nevada rim towers from Arizona side. Left tower supports Circuit 6, middle tower supports Circuit 5, and right tower supports Circuits 4 and 15, view north - Hoover Dam, Circuits 1-15, U.S. Highway 93, Boulder City, Clark County, NV

  17. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey. Final report

    SciTech Connect

    1981-03-01

    Solar heating and cooling of a 40,000 square foot manufacturing building, sales offices and the solar computer control center/display room are described. Information on system description, test data, major problems and resolutions, performance, operation and maintenance manual, manufacturer's literature and as-built drawings are provided also. The solar system is composed of 6000 square feet of Sunworks double glazed flat plate collectors, external above ground storage subsystem, controls, ARKLA absorption chiller, heat recovery and a cooling tower.

  18. Measured performance of a 3-ton LiBr absorption water chiller and its effect on cooling system operation

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1976-01-01

    A 3-ton lithium bromide absorption water chiller was tested for a number of conditions involving hot-water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It is concluded that a 3-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

  19. Measured performance of a 3 ton LiBr absorption water chiller and its effect on cooling system operation

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1976-01-01

    A three ton lithium bromide absorption water chiller was tested for a number of conditions involving hot water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It was concluded that a three-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

  20. Effects of whole body cooling on sensory perception and manual performance in subjects with Raynaud's phenomenon.

    PubMed

    Rissanen, S; Hassi, J; Juopperi, K; Rintamäki, H

    2001-04-01

    Patients with Raynaud's phenomenon (RP) have abnormal digital vasoconstriction in response to cold. The aim of the study was to investigate the effects of cooling on sensory perception and manual performance in healthy male subjects and subjects with RP. There were two groups of subjects with primary RP: 12 subjects fulfilled the criteria of Lewis (L) and the other 12 the more critical criteria of Maricq (M). Control group (C) consisted of 19 healthy men. Subjects were exposed to 5 degrees C for 60 min. Skin temperatures were measured. Finger dexterity, pinch strength, abduction/adduction of fingers, pressure perception threshold and vibration perception threshold were tested during the exposure every 15 min. At the beginning of the exposure the mean (S.E.) finger temperature was 2.5 (1.2) degrees C (P<0.05) lower in M than in C. Manual performance and sensory perception were impaired due to the cooling, the impairment being significantly greater in M than in C. Responses of L were between those of M and C. In a given finger temperature vibration and pressure sensibility and manual performance were lower in M and L than in C. In conclusion, cold exposure decreased sensory perception and manual performance in the subjects with RP to a lower level than in the healthy subjects. Non-thermal factors may also decrease performance in RP.

  1. Tower Camera Handbook

    SciTech Connect

    Moudry, D

    2005-01-01

    The tower camera in Barrow provides hourly images of ground surrounding the tower. These images may be used to determine fractional snow cover as winter arrives, for comparison with the albedo that can be calculated from downward-looking radiometers, as well as some indication of present weather. Similarly, during spring time, the camera images show the changes in the ground albedo as the snow melts. The tower images are saved in hourly intervals. In addition, two other cameras, the skydeck camera in Barrow and the piling camera in Atqasuk, show the current conditions at those sites.

  2. DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS SEVEN,EIGHT, NINE, TEN, AND BREAK OVER TOWER IN DISTANCE, LOOKING NORTH. TOWER SIX IS THE LAST BEFORE A DEEP CHASM, AS IS SEEN BY THE DISTANCE BETWEEN TOWERS SIX AND SEVEN. SEE CA-291-48 (CT) FOR IDENTICAL COLOR TRANSPARENCY. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  3. DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER SIX WITH TOWERS SEVEN, EIGHT, NINE, TEN, AND BREAK OVER TOWER IN DISTANCE, LOOKING NORTH. TOWER SIX IS THE LAST BEFORE A DEEP CHASM, AS IS SEEN BY THE DISTANCE BETWEEN TOWERS SIX AND SEVEN. SEE CA-291-21 FOR IDENTICAL B&W NEGATIVE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  4. Energy penalty analysis of possible cooling water intake structurerequirements on existing coal-fired power plants.

    SciTech Connect

    Veil, J. A.; Littleton, D. J.; Gross, R. W.; Smith, D. N.; Parsons, E.L., Jr.; Shelton, W. W.; Feeley, T. J.; McGurl, G. V.

    2006-11-27

    dissolved solids. Makeup water is withdrawn, usually from surface water bodies, to replace the lost water. The volume of makeup water is many times smaller than the volume needed to operate a once-through system. Although neither the final new facility rule nor the proposed existing facility rule require dry cooling towers as the national best technology available, the environmental community and several States have supported the use of dry-cooling technology as the appropriate technology for addressing adverse environmental impacts. It is possible that the requirements included in the new facility rule and the ongoing push for dry cooling systems by some stakeholders may have a role in shaping the rule for existing facilities. The temperature of the cooling water entering the condenser affects the performance of the turbine--the cooler the temperature, the better the performance. This is because the cooling water temperature affects the level of vacuum at the discharge of the steam turbine. As cooling water temperatures decrease, a higher vacuum can be produced and additional energy can be extracted. On an annual average, once-through cooling water has a lower temperature than recirculated water from a cooling tower. By switching a once-through cooling system to a cooling tower, less energy can be generated by the power plant from the same amount of fuel. This reduction in energy output is known as the energy penalty. If a switch away from once-through cooling is broadly implemented through a final 316(b) rule or other regulatory initiatives, the energy penalty could result in adverse effects on energy supplies. Therefore, in accordance with the recommendations of the Report of the National Energy Policy Development Group (better known as the May 2001 National Energy Policy), the U.S. Department of Energy (DOE), through its Office of Fossil Energy, National Energy Technology Laboratory (NETL), and Argonne National Laboratory (ANL), has studied the energy penalty resulting

  5. Cooling performance and evaluation of automotive refrigeration system for a passenger car

    NASA Astrophysics Data System (ADS)

    Prajitno, Deendarlianto, Majid, Akmal Irfan; Mardani, Mahardeka Dhias; Wicaksono, Wendi; Kamal, Samsul; Purwanto, Teguh Pudji; Fauzun

    2016-06-01

    A new design of automotive refrigeration system for a passenger car was proposed. To ensure less energy consumption and optimal thermal comfort, the performance of the system were evaluated. This current research was aimed to evaluate the refrigeration characteristics of the system for several types of cooling load. In this present study, a four-passenger wagon car with 1500 cc gasoline engine that equipped by a belt driven compressor (BDC) was used as the tested vehicle. To represent the tropical condition, a set of lamps and wind sources are installed around the vehicle. The blower capacity inside a car is varied from 0.015 m/s to 0.027 m/s and the compressor speed is varied at variable 820, 1400, and 2100 rpm at a set temperature of 22°C. A set of thermocouples that combined by data logger were used to measure the temperature distribution. The system uses R-134a as the refrigerant. In order to determine the cooling capacity of the vehicle, two conditions were presented: without passengers and full load conditions. As the results, cooling capacity from any possible heating sources and transient characteristics of temperature in both systems for the cabin, engine, compressor, and condenser are presented in this work. As the load increases, the outlet temperature of evaporator also increases due to the increase of condensed air. This phenomenon also causes the increase of compressor work and compression ratio which associated to the addition of specific volume in compressor inlet.

  6. Techno-economic performance evaluation of direct steam generation solar tower plants with thermal energy storage systems based on high-temperature concrete and encapsulated phase change materials

    NASA Astrophysics Data System (ADS)

    Guédez, R.; Arnaudo, M.; Topel, M.; Zanino, R.; Hassar, Z.; Laumert, B.

    2016-05-01

    Nowadays, direct steam generation concentrated solar tower plants suffer from the absence of a cost-effective thermal energy storage integration. In this study, the prefeasibility of a combined sensible and latent thermal energy storage configuration has been performed from thermodynamic and economic standpoints as a potential storage option. The main advantage of such concept with respect to only sensible or only latent choices is related to the possibility to minimize the thermal losses during system charge and discharge processes by reducing the temperature and pressure drops occurring all along the heat transfer process. Thermodynamic models, heat transfer models, plant integration and control strategies for both a pressurized tank filled with sphere-encapsulated salts and high temperature concrete storage blocks were developed within KTH in-house tool DYESOPT for power plant performance modeling. Once implemented, cross-validated and integrated the new storage model in an existing DYESOPT power plant layout, a sensitivity analysis with regards of storage, solar field and power block sizes was performed to determine the potential impact of integrating the proposed concept. Even for a storage cost figure of 50 USD/kWh, it was found that the integration of the proposed storage configuration can enhance the performance of the power plants by augmenting its availability and reducing its levelized cost of electricity. As expected, it was also found that the benefits are greater for the cases of smaller power block sizes. Specifically, for a power block of 80 MWe a reduction in levelized electricity costs of 8% was estimated together with an increase in capacity factor by 30%, whereas for a power block of 126 MWe the benefits found were a 1.5% cost reduction and 16% availability increase.

  7. Performance evaluation of the hydronic heat pump system: Volume 2, Cooling season. Final report

    SciTech Connect

    Gupta, S.; Stoltz, S.; Hagen, E.

    1995-04-01

    A hydronic heat pump system has been developed under EPRI sponsorship as a potential substitute for conventional residential forced-air heat pumps. The use of a hydronic thermal distribution system of circulating water to distribute the output of a residential heat pump compares favorably with other methods of distribution. To evaluate the performance of a hydronic heat pump compared to a conventional forced-air system, EPRI retained GEOMET Technologies, Inc., to test a prototype hydronic system in the controlled environment of an unoccupied research house. A prototype multizone hydronic system, developed and assembled by the Tecogen Division of Thermal Power Corporation, was tested in one of GEOMET`s two research houses during the 1992--1993 heating season and in the 1993 cooling season. This report describes the cooling-season tests of the hydronic heat pump system. The prototype hydronic system was tested to examine its efficiency and reliability. It was tested under several scenarios having different combinations of setpoints while the internal doors were either open or closed. The test data were analyzed to compare the hydronic system`s energy consumption, comfort, and efficiency to those of a conventional forced-air heat pump system. The hydronic system ran smoothly, and there were no operational problems in the cooling mode, though the hydronic system required more energy than the conventional system under comparable test conditions. However, the hydronic system provided a level of thermal comfort equivalent to that of the conventional system. Overall energy efficiency of the hydronic system might be improved with minor modifications in the operating/control scheme to increase low speed compressor operation, reduce compressor cycling and by circulating the water through the system only when heating or cooling is required in any of the zones.

  8. Performance and private speech of children with attention-deficit/hyperactivity disorder while taking the Tower of Hanoi test: effects of depth of search, diagnostic subtype, and methylphenidate.

    PubMed

    Kopecky, Helena; Chang, H Theresa; Klorman, Rafael; Thatcher, Joan E; Borgstedt, Agneta D

    2005-10-01

    We administered the Tower of Hanoi to demographically comparable samples of control participants (n = 34) and children with the Combined (n = 22) and Inattentive subtypes (n = 19) of Attention-Deficit/Hyperactivity Disorder (ADHD). Controls excelled over children with the Inattentive subtype, who outperformed patients with the Combined subtype. These results replicated findings of greater executive deficits in the Combined than in the Inattentive type of ADHD. Double-blind administration of methylphenidate improved task performance only for patients with the Inattentive subtype. In a drug-free Baseline session, children with both subtypes of ADHD made more private verbalizations than controls, particularly when failing puzzles. In later sessions, regardless of drug condition, the inattentive sample exhibited a smaller increase in self-regulatory utterances under failure. In contrast, the combined sample decreased self-regulatory verbalizations under failure only under methylphenidate. The results support some differences between the two subtypes of ADHD in executive functioning and in their response to stimulant therapy. PMID:16195955

  9. Aquarius: Tower Rollback

    NASA Video Gallery

    The mobile service tower at NASA's Launch Complex-2 at Vandenberg Air Force Base in California is being moved away from the ULA Delta II rocket with the Aquarius/SAC-D spacecraft atop, in preparati...

  10. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Manufacturer's rated cooling capacities (Btu's/hr.) Range of SEER's Low High Single Package Units Central Air Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps...

  11. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps (Cooling... Conditioners H Appendix H to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER...

  12. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps (Cooling... Conditioners H Appendix H to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER...

  13. Thermal Performance of a Dual-Channel, Helium-Cooled, Tungsten Heat Exchanger

    SciTech Connect

    YOUCHISON,DENNIS L.; NORTH,MART T.

    2000-11-22

    Helium-cooled, refractory heat exchangers are now under consideration for first wall and divertor applications. These refractory devices take advantage of high temperature operation with large delta-Ts to effectively handle high heat fluxes. The high temperature helium can then be used in a gas turbine for high-efficiency power conversion. Over the last five years, heat removal with helium was shown to increase dramatically by using porous metal to provide a very large effective surface area for heat transfer in a small volume. Last year, the thermal performance of a bare-copper, dual-channel, helium-cooled, porous metal divertor mock-up was evaluated on the 30 kW Electron Beam Test System at Sandia National Laboratories. The module survived a maximum absorbed heat flux of 34.6 MW/m{sup 2} and reached a maximum surface temperature of 593 C for uniform power loading of 3 kW absorbed on a 2-cm{sup 2} area. An impressive 10 kW of power was absorbed on an area of 24 cm{sup 2}. Recently, a similar dual-module, helium-cooled heat exchanger made almost entirely of tungsten was designed and fabricated by Thermacore, Inc. and tested at Sandia. A complete flow test of each channel was performed to determine the actual pressure drop characteristics. Each channel was equipped with delta-P transducers and platinum RTDs for independent calorimetry. One mass flow meter monitored the total flow to the heat exchanger, while a second monitored flow in only one of the channels. The thermal response of each tungsten module was obtained for heat fluxes in excess of 5 MW/m{sup 2} using 50 C helium at 4 MPa. Fatigue cycles were also performed to assess the fracture toughness of the tungsten modules. A description of the module design and new results on flow instabilities are also presented.

  14. How planful is routine behavior? A selective-attention model of performance in the Tower of Hanoi.

    PubMed

    Patsenko, Elena G; Altmann, Erik M

    2010-02-01

    Routine human behavior has often been attributed to plans-mental representations of sequences goals and actions-but can also be attributed to more opportunistic interactions of mind and a structured environment. This study asks whether performance on a task traditionally analyzed in terms of plans can be better understood from a "situated" (or "embodied") perspective. A saccade-contingent display-updating paradigm is used to change the environment by adding, deleting, and moving task-relevant objects without participants' direct awareness. Response latencies, action patterns, and eye movements all indicate that performance is guided not by plans stored in memory but by a control routine bound to objects as needed by perception and selective attention. The results have implications for interpreting everyday task performance and particular neuropsychological deficits. PMID:20121314

  15. Drop Tower Workshop

    NASA Technical Reports Server (NTRS)

    Urban, David

    2013-01-01

    Ground based microgravity facilities are an important proving ground for space experiments, ground-based research and space hardware risk mitigation. An overview of existing platforms will be discussed with an emphasis on drop tower capabilities. The potential for extension to partial gravity conditions will be discussed. Input will be solicited from attendees for their potential to use drop towers in the future and the need for enhanced capabilities (e.g. partial gravity)

  16. Analysis of data user's needs for performance evaluation of solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Christensen, D. L.

    1978-01-01

    In a successful data acquisition program, the information needs must be evaluated, the design and cost factors of the program must be determined, and a data management loop must be organized and operated in order to collect, process, and disseminate the needed information in useable formats. This paper describes each of these program elements in detail as an aid for the solar heating and cooling data manager and user to implement effective data acquisition and monitoring systems. Consideration is given to the development of evaluation techniques which will aid in the determination of solar energy systems performances.

  17. Lagrangian and Control Volume Models for Prediction of Cooling Lake Performance at SRP

    SciTech Connect

    Garrett, A.J.

    2001-06-26

    The model validation described in this document indicates that the methods described here and by Cooper (1984) for predicting the performance of the proposed L-Area cooling lake are reliable. Extensive observations from the Par Pond system show that lake surface temperatures exceeding 32.2 degrees C (90 degrees F) are attained occasionally in the summer in areas where there is little or no heating from the P-Area Reactor. Regulations which restrict lake surface temperatures to less than 32.2 degrees C should be structured to allow for these naturally-occurring thermal excursions.

  18. How Planful Is Routine Behavior? A Selective-Attention Model of Performance in the Tower of Hanoi

    ERIC Educational Resources Information Center

    Patsenko, Elena G.; Altmann, Erik M.

    2010-01-01

    Routine human behavior has often been attributed to plans--mental representations of sequences goals and actions--but can also be attributed to more opportunistic interactions of mind and a structured environment. This study asks whether performance on a task traditionally analyzed in terms of plans can be better understood from a "situated" (or…

  19. Hovering and Low-Speed Performance and Control Characteristics of the Kaman Helicopter Rotor System as Determined on the Langley Helicopter Tower. TED No. NACA DE 205

    NASA Technical Reports Server (NTRS)

    Carpenter, Paul J.; Paulnock, Russell S.

    1949-01-01

    An investigation has been conducted with the Langley helicopter tower to obtain basic performance and control characteristics of the Raman rotor system. Blade-pitch control is obtained in this configuration by utilizing an auxiliary flap to twist the blades. Rotor thrust and power required were measured for the hovering condition and over a range of wind velocities from 0 to 30 miles per hour. The control characteristics and the transient response of the rotor to various control movements were also measured. The hovering-performance data are presented as a survey of the wake velocities and the variation of torque coefficient with thrust coefficient. The power required for the test rotor to hover at a thrust of 1350 pounds and a rotor speed of 240 rpm is approximately 6.5 percent greater than that estimated for a conventional rotor of the same diameter and solidity. It is believed that most of this difference is caused by th e flap servomechanism. The reduction in total power required for sustentation of the single-rotor configuration tested at various wind velocities and at the normal operating rotor thrust was found to be similar to the theoretical and experimental results for ro tors with conventionally actuated pitch. The control effectiveness was determined as a function of rotor speed. Sufficient control was available to give a thrust range of 0 to 1500 pounds and a rotor tilt of plus or minus 7 degrees. The time lag between flap motion and blade-pitch response is approximately 0.02 to 0.03 second. The response of the rotor following the blade-pitch response is similar to that of a rotor with conventionally actuated pitch changes. The over-all characteristics of the rotor investigated indicate that satisfactory performance and control characteristics were obtained.

  20. Heat transfer and performance characteristics of axial cooling fans with downstream guide vanes

    NASA Astrophysics Data System (ADS)

    Terzis, Alexandros; Stylianou, Ioannis; Kalfas, Anestis I.; Ott, Peter

    2012-04-01

    This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complete stage, was used for all the experimental configurations. Performance measurements were carried out in a constant speed stage performance test rig while the transient liquid crystal technique was used for the heat transfer measurements. Full surface heat transfer coefficient distributions were obtained by recording the temperature history of liquid crystals on a target plate. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Stators can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as, in the local heat transfer distribution at the wake of the stator blades if the fan is installed very close to the cooling object. However, as the separation distance increases, enhanced heat transfer rate in the order of 25% is observed in the case of the fan impeller.

  1. CrossTalk proposal: Heat acclimatization does improve performance in a cool condition.

    PubMed

    Minson, Christopher T; Cotter, James D

    2016-01-15

    We believe available data support the thesis that HA can improve performance in cool conditions, and perhaps with less expense and fewer side-effects than hypoxia (Dempsey & Morgan, 2015), but its utility is unresolved and may be modest or absent in some settings and individuals. A few key issues are becoming clear, however. First, HA must be of sufficient stimulus and duration, with key evidence indicating longer is better. Second, individual variability in response to HA as an ergogenic aid needs to be considered. Third, key training aspects such as speed and intensity may need to be maintained, and ideally performed in a cooler environment to maximize gains and minimize fatigue (including the effects of matched absolute versus relative work rates on adaptations). Alternatively, passive heating should be considered (e.g. immediately after training). Fourth, there is no evidence that HA impairs cool weather performance, and thus HA is a useful strategy when the competitive environmental conditions are potentially hot or unknown. Fifth, much remains unknown about ideal timing for competition following HA and its decay. Lastly, an ergogenic effect of HA has yet to be studied in truly elite athletes.

  2. Investigation on the cooling performance of a compact heat exchanger using nanofluids

    NASA Astrophysics Data System (ADS)

    Abdul Jalal, M. F.; Shuaib, N. H.; Gunnasegaran, P.; Sandhita, E.

    2012-11-01

    In this paper, analysis of ethylene glycol (EG) as a base fluid with aluminum dioxide (Al2O3), diamond (DM), silicon dioxide (SiO2) and titanium dioxide (TiO2) as the coolants on compact heat exchangers (CHEs) with flattened tube plate fin is performed. By using ɛ-NTU rating method the cooling performance under cross flow arrangement of the CHEs with unmixed air and nanofluid as coolant will be investigated. The nanoparticles volume fraction φ is varied from 0 % to 4 %. The mathematical formulation, nanofluid properties and relevant input data are extracted from literatures. The CHE performance with respect to heat transfer coefficient, pressure drop and pumping power by means of MATLAB SIMULINK is investigated. The result shows that with the increase of nanoparticles volume fraction and nanofluid Reynold number, the CHE exhibits enhancement in term of heat transfer coefficient with the penalty of increase in pressure drop as well as pumping power.

  3. Evaluating Performance, Power, and Cooling in High Performance Computing (HPC) Data Centers

    SciTech Connect

    Evans, Jeffrey; Sandeep, Gupta; Karavanic, Karen; Marquez, Andres; Varsamopoulos, Girogios

    2012-01-24

    This chapter explores current research focused on developing our understanding of the interrelationships involved with HPC performance and energy management. The first section explores data center instrumentation, measurement, and performance analysis techniques, followed by a section focusing on work in data center thermal management and resource allocation. This is followed by an exploration of emerging techniques to identify application behavioral attributes that can provide clues and advice to HPC resource and energy management systems for the purpose of balancing HPC performance and energy efficiency.

  4. Assessment of thermal performance for the design of a passively-cooled plutonium storage vault

    NASA Astrophysics Data System (ADS)

    Sanders, Joseph Conway

    A passively-cooled plutonium storage vault, rather than one with a safety-qualified, forced-flow cooling system, could save as much as 100 million over the project lifetime. Either configuration must maintain the temperature of the stored plutonium metal, with its significant internal heat generation, below 239 sp circF. Alpha-phase metal, if allowed to exceed this temperature, will transition to beta-phase metal and undergo a volumetric expansion which could rupture the storage container system. An investigation was performed to determine whether a passively-cooled vault is feasible. Significant temperature drops occurred in two regions, both were gas-filled vertical annuli with heat flux boundary conditions on the inner surfaces and fixed temperature boundary conditions on the outer surfaces. The thermal resistance method was employed to evaluate radial heat transfer across each annulus, coupling natural convection, radiation, and conduction. Correlations from Thomas et al and Kulacki et al were used to evaluate the degree of natural convective enhancement. For the helium-filled region between the plutonium metal rod and the container with a characteristic length of 3.9 centimeters and an aspect ratio of 5.6, the Rayleigh number was 800 when the effect of radiation was removed. This resulted in a Nusselt number of 1.8. For the air-filled region between twelve vertically arranged containers and the storage tube with a characteristic length of 5.8 centimeters and an aspect ratio of 78, the Rayleigh number was 5times10sp5. This resulted in a Nusselt number of approximately 4.5, neglecting the effect of radiation. FIDAP 7.62\\copyright$ (Fluid Dynamics Analysis Package) was used to perform multi-dimensional finite element analyses of these regions employing both buoyant and radiative effects. Both simplified and more geometrically complex models were employed, all of which compared favorably to the results using the thermal resistance method. The results of the

  5. Performance of cryogenically cooled, high-heat-load silicon crystal monochromators with porous media augmentation

    SciTech Connect

    Rogers, C.S.; Mills, D.M.; Assoufid, L.; Graber, T.

    1996-09-01

    The performance of two Si crystal x-ray monochromators internally cooled with liquid nitrogen was tested on the F2-wiggler beamline at the Cornell High Energy Synchrotron Source (CHESS). Both crystals were (111)-oriented blocks of rectangular cross section having identical dimensions. Seven 6.4-mm-diameter coolant channels were drilled through the crystals along the beam direction. In one of the crystals, porous Cu mesh inserts were bonded into the channels to enhance the heat transfer. The channels of the second crystal were left as drilled. Symmetric, double-crystal rocking curves were recorded simultaneously for both the first and third order reflections at 8 and 24 keV. The power load on the cooled crystal was adjusted by varying the horizontal beam size using slits. The measured Si(333) rocking curve of the unenhanced crystal at 24 keV at low power was 1.9 arcsec FWHM. The theoretical width is 0.63 arcsec. The difference is due to residual fabrication and mounting strain. For a maximum incident power of 601 W and an average power density of about 10 W/mm{sup 2}, the rocking curve was 2.7 arcsec. The rocking curve width for the enhanced crystal at low power was 2.4 arcsec. At a maximum incident power of 1803 W and an average power density of about 19 W/mm{sup 2}, the rocking curve width was 2.2 arcsec FWHM. The use of porous mesh augmentation is a simple, but very effective, means to improve the performance of cryogenically cooled Si monochromators exposed to high power x-ray beams. {copyright} {ital 1996 American Institute of Physics.}

  6. Experimental and numerical investigation on the performance of an internally cooled dehumidifier

    NASA Astrophysics Data System (ADS)

    Turgut, Oguz Emrah; Çoban, Mustafa Turhan

    2016-02-01

    Liquid desiccant based dehumidifiers are important components of the air conditioning applications. Internally cooled dehumidifiers with liquid desiccants are deemed to be superior to the adiabatic types, thanks to the cooling medium which takes away the latent heat of vaporization occured when moist air contacts with liquid desiccant. However, its utilization in industrial applications is restricted due to the inherent corrosive characteristics of the liquid desiccants. In this study, an experimental chamber is built for epoxy coated plate fin type dehumidifier which is used in order to diminish the corrosive effect of the lithium chloride aqueous solution. Dehumidification effectiveness and moisture removal rate, two parameter indices, are adopted to measure the performance of the air conditioning system. The effect of inlet operating parameters on moisture removal rates is extensively analyzed. Two dimensional numerical model adapted from the conservation principles is utilized for obtainment of output parameters. Experimental results are compared with the numerical model and comparisons show that numerical outputs agrees with the experimental results. And also, dehumidification performance of lithium chloride and lithium bromide aqueous solutions are evaluated and compared against each other.

  7. The prediction of nozzle performance and heat transfer in hydrogen/oxygen rocket engines with transpiration cooling, film cooling, and high area ratios

    NASA Technical Reports Server (NTRS)

    Kacynski, Kenneth J.; Hoffman, Joe D.

    1993-01-01

    An advanced engineering computational model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multi-species, chemically reacting and diffusing Navier-Stokes equations are modelled, finite difference approach that is tailored to be conservative in an axisymmetric coordinate system for both the inviscid and viscous terms. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and transpiration cooled plug-and-spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 nozzle and the film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent plug-and-spool rocket engine analysis cases performed. Further, the Soret term was shown to represent a significant fraction of the diffusion fluxes occurring in the transpiration cooled rocket engine.

  8. Experimental and Numerical Investigations of Effects of Flow Control Devices Upon Flat-Plate Film Cooling Performance.

    PubMed

    Kawabata, Hirokazu; Funazaki, Ken-Ichi; Nakata, Ryota; Takahashi, Daichi

    2014-06-01

    This study deals with the experimental and numerical studies of the effect of flow control devices (FCDs) on the film cooling performance of a circular cooling hole on a flat plate. Two types of FCDs with different heights are examined in this study, where each of them is mounted to the flat plate upstream of the cooling hole by changing its lateral position with respect to the hole centerline. In order to measure the film effectiveness as well as heat transfer downstream of the cooling hole with upstream FCD, a transient method using a high-resolution infrared camera is adopted. The velocity field downstream of the cooling hole is captured by 3D laser Doppler velocimeter (LDV). Furthermore, the aerodynamic loss associated with the cooling hole with/without FCD is measured by a total pressure probe rake. The experiments are carried out at blowing ratios ranging from 0.5 to 1.0. In addition, numerical simulations are also made to have a better understanding of the flow field. LES approach is employed to solve the flow field and visualize the vortex structure around the cooling hole with FCD. When a taller FCD is mounted to the plate, the film effectiveness tends to increase due to the vortex structure generated by the FCD. As FCD is laterally shifted from the centerline, the film effectiveness increases, while the lift-off of cooling air is also promoted when FCD is put on the center line. PMID:25278646

  9. Cooling vest worn during active warm-up improves 5-km run performance in the heat.

    PubMed

    Arngrïmsson, Sigurbjörn A; Petitt, Darby S; Stueck, Matthew G; Jorgensen, Dennis K; Cureton, Kirk J

    2004-05-01

    We investigated whether a cooling vest worn during an active warm-up enhances 5-km run time in the heat. Seventeen competitive runners (9 men, maximal oxygen uptake = 66.7 +/- 5.9 ml x kg(-1) x min(-1); 8 women, maximal oxygen uptake = 58.0 +/- 3.2 ml x kg(-1) x min(-1)) completed two simulated 5-km runs on a treadmill after a 38-min active warm-up during which they wore either a T-shirt (C) or a vest filled with ice (V) in a hot, humid environment (32 degrees C, 50% relative humidity). Wearing the cooling vest during warm-up significantly (P < 0.05) blunted increases in body temperature, heart rate (HR), and perception of thermal discomfort during warm-up compared with control. At the start of the 5-km run, esophageal, rectal, mean skin, and mean body temperatures averaged 0.3, 0.2, 1.8, and 0.4 degrees C lower; HR averaged 11 beats/min lower; and perception of thermal discomfort (5-point scale) averaged 0.6 point lower in V than C. Most of these differences were eliminated during the first 3.2 km of the run, and these variables were not different at the end. The 5-km run time was significantly lower (P < 0.05) by 13 s in V than C, with a faster pace most evident during the last two-thirds of the run. We conclude that a cooling vest worn during active warm-up by track athletes enhances 5-km run performance in the heat. Reduced thermal and cardiovascular strain and perception of thermal discomfort in the early portion of the run appear to permit a faster pace later in the run.

  10. Combination of Ultrasonic Vibration and Cryogenic Cooling for Cutting Performance Improvement of Inconel 718 Turning

    NASA Astrophysics Data System (ADS)

    Lin, S. Y.; Chung, C. T.; Cheng, Y. Y.

    2011-01-01

    The main objective of this study is to develop a thermo-elastic-plastic coupling model, based on a combination skill of ultrasonically assisted cutting and cryogenic cooling, under large deformation for Inconel 718 alloy machining process. The improvement extent on cutting performance and tool life promotion may be examined from this investigation. The critical value of the strain energy density of the workpiece will be utilized as the chip separation and the discontinuous chip segmentation criteria. The forced convection cooling and a hydrodynamic lubrication model will be considered and formulated in the model. Finite element method will be applied to create a complete numerical solution for this ultrasonic vibration cutting model. During the analysis, the cutting tool is incrementally advanced forward with superimposed ultrasonic vibration in a back and forth step-by-step manner, from an incipient stage of tool-workpiece engagement to a steady state of chip formation, a whole simulation of orthogonal cutting process under plane strain deformation is thus undertaken. High shear strength induces a fluctuation phenomenon of shear angle, high shear strain rate, variation of chip types and chip morphology, tool-chip contact length variation, the temperature distributions within the workpiece, chip and tool, periodic fluctuation in cutting forces can be determined from the developed model. A complete comparison of machining characteristics between some different combinations of ultrasonically assisted cutting and cryogenic cooling with conventional cutting operation can be acquired. Finally, the high-speed turning experiment for Inconel 718 alloy will be taken in the laboratory to validate the accuracy of the model, and the progressive flank wear, crater wear, notching and chipping of the tool edge can also be measured in the experiments.

  11. A comparison of the analytical and experimental performance of the solid version of a cooled radial turbine

    NASA Technical Reports Server (NTRS)

    Tirres, Lizet

    1991-01-01

    An evaluation of the aerodynamic performance of the solid version of an Allison-designed cooled radial turbine was conducted at NASA Lewis' Warm Turbine Test Facility. The resulting pressure and temperature measurements are used to calculate vane, rotor, and overall stage performance. These performance results are then compared to the analytical results obtained by using NASA's MTSB (MERIDL-TSONIC-BLAYER) code.

  12. 3. VIEW NORTHWEST, height finder radar towers, and radar tower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW NORTHWEST, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  13. DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER TWO, WITH TOWERS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF AERIAL TRAM SUPPORT TOWER TWO, WITH TOWERS THREE,FOUR, FIVE AND SIX IN DISTANCE, LOOKING NORTHEAST. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  14. 69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER UNDER CONSTRUCTION. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  15. 26. STATIC TEST TOWER CONTROL PANELS AT REAR OF TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. STATIC TEST TOWER CONTROL PANELS AT REAR OF TOWER UNDERNEATH SHED ROOF. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

  16. 8. GENERAL VIEW OF TOWER 32, LEFT, AND TOWER 31, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. GENERAL VIEW OF TOWER 32, LEFT, AND TOWER 31, RIGHT. VIEW LOOKING NORTH SHOWING AERIAL WIRE DESIGN WITH VERTICAL 'TOP HAT' WIRES IN CENTER. - Chollas Heights Naval Radio Transmitting Facility, 6410 Zero Road, San Diego, San Diego County, CA

  17. Effect of Film-Hole Shape on Turbine Blade Film Cooling Performance

    NASA Technical Reports Server (NTRS)

    Han, J. C.; Teng, S.

    2000-01-01

    The detailed heat transfer coefficient and film cooling effectiveness distributions as well as tile detailed coolant jet temperature profiles on the suction side of a gas turbine blade A,ere measured using a transient liquid crystal image method and a traversing cold wire and a traversing thermocouple probe, respectively. The blade has only one row of film holes near the gill hole portion on the suction side of the blade. The hole geometries studied include standard cylindrical holes and holes with diffuser shaped exit portion (i.e. fanshaped holes and laidback fanshaped holes). Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity was 5.3 x 10(exp 5). Upstream unsteady wakes were simulated using a spoke-wheel type wake generator. The wake Strouhal number was kept at 0 or 0.1. Coolant blowing ratio was varied from 0.4 to 1.2. Results show that both expanded holes have significantly improved thermal protection over the surface downstream of the ejection location, particularly at high blowing ratios. However, the expanded hole injections induce earlier boundary layer transition to turbulence and enhance heat transfer coefficients at the latter part of the blade suction surface. In general, the unsteady wake tends to reduce film cooling effectiveness.

  18. The performance of a cryogenically cooled monochromator for an in-vacuum undulator beamline.

    PubMed

    Zhang, Lin; Lee, Wah Keat; Wulff, Michael; Eybert, Laurent

    2003-07-01

    The channel-cut silicon monochromator on beamline ID09 at the European Synchrotron Radiation Facility is indirectly cooled from the sides by liquid nitrogen. The thermal slope error of the diffracting surface is calculated by finite-element analysis and the results are compared with experiments. The slope error is studied as a function of cooling coefficients, beam size, position of the footprint and power distribution. It is found that the slope error versus power curve can be divided into three regions: (i). The linear region: the thermal slope error is linearly proportional to the power. (ii). The transition region: the temperature of the Si crystal is close to 125 K; the thermal slope error is below the straight line extrapolated from the linear curve described above. (iii). The non-linear region: the temperature of the Si crystal is higher than 125 K and the thermal slope error increases much faster than the power. Heat-load tests were also performed and the measured rocking-curve widths are compared with those calculated by finite-element modeling. When the broadening from the intrinsic rocking-curve width and mounting strain are included, the calculated rocking-curve width versus heat load is in excellent agreement with experiment. PMID:12824931

  19. Improving film cooling performance by using one -inlet and double-outlet hole

    NASA Astrophysics Data System (ADS)

    Li, Guang-Chao; Zhang, Wei

    2010-10-01

    The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the trunk hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round hole as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes. The optimal blowing ratios occur at M=1.0 or M=1.5 according to the various locations downstream of the holes.

  20. Cool-down performance of the new apparatus for fuel layering demonstrations of FIREX targets

    NASA Astrophysics Data System (ADS)

    Iwamoto, A.; Norimatsu, T.; Nakai, M.; Sakagami, H.; Shiraga, H.; Azechi, H.

    2016-03-01

    FIREX targets have been developed under two layering strategies: foam shell and cone guide laser heating methods. Basic studies have been conducted by the collaboration research between ILE and NIFS. Then the next stage requires the characterization of a layered solid fuel. The present system is at the disadvantage of optical observations. Therefore, a new apparatus is designed to solve it. Glass windows with a wide aperture are installed for an interferometer and a microscope. To isolate the vibration from a cryocooler, active vibration control units are equipped, and flexible thermal conductive links are utilized. Furthermore, a quick target exchange mechanism is applied to deal with different types of FIREX targets. A target holder is detachable from a main vacuum chamber. A metal gasket with not fixing bolts but a load of ∼ thousand newtons on ensures GHe leak tightness for target cooling. Eventually, the design temperature of 10.00 K at a target container has been achieved. The cool-down performance indecates that the new apparatus provides a cryogenic environment for fuel layering demonstrations.

  1. The performance of a mobile air conditioning system with a water cooled condenser

    NASA Astrophysics Data System (ADS)

    Di Battista, Davide; Cipollone, Roberto

    2015-11-01

    Vehicle technological evolution lived, in recent years, a strong acceleration due to the increased awareness of environmental issues related to pollutants and climate altering emissions. This resulted in a series of international regulations on automotive sector which put technical challenges that must consider the engine and the vehicle as a global system, in order to improve the overall efficiency of the system. The air conditioning system of the cabin, for instance, is the one of the most important auxiliaries in a vehicle and requires significant powers. Its performances can be significantly improved if it is integrated within the engine cooling circuit, eventually modified with more temperature levels. In this paper, the Authors present a mathematical model of the A/C system, starting from its single components: compressors, condenser, flush valve and evaporator and a comparison between different refrigerant fluid. In particular, it is introduced the opportunity to have an A/C condenser cooled by a water circuit instead of the external air linked to the vehicle speed, as in the actual traditional configuration. The A/C condenser, in fact, could be housed on a low temperature water circuit, reducing the condensing temperature of the refrigeration cycle with a considerable efficiency increase.

  2. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... for Central Air Conditioners Manufacturer's rated cooling capacities (Btu's/hr.) Range of SEER's Low High Single Package Units Central Air Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps...): All capacities 10.9 23.0 Heat Pumps (Cooling Function): All capacities 10.9 21.0...

  3. Loss of coolant analysis for the tower shielding reactor 2

    SciTech Connect

    Radcliff, T.D.; Williams, P.T.

    1990-06-01

    The operational limits of the Tower Shielding Reactor-2 (TSR-2) have been revised to account for placing the reactor in a beam shield, which reduces convection cooling during a loss-of-coolant accident (LOCA). A detailed heat transfer analysis was performed to set operating time limits which preclude fuel damage during a LOCA. Since a LOCA is survivable, the pressure boundary need not be safety related, minimizing seismic and inspection requirements. Measurements of reactor component emittance for this analysis revealed that aluminum oxidized in water may have emittance much higher than accepted values, allowing higher operating limits than were originally expected. These limits could be increased further with analytical or hardware improvements. 5 refs., 7 figs.

  4. THE TOWER HOUSE, LOOKING WEST. The tower house provided a ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    THE TOWER HOUSE, LOOKING WEST. The tower house provided a water tank on the second floor that gravity fed water to the Kineth house and farm buildings. The one-story addition to the west of the tower provided workshop space. The hog shed is seen on the left of the image and the concrete foundation of the upright silo is in the foreground on the right. - Kineth Farm, Tower House, 19162 State Route 20, Coupeville, Island County, WA

  5. Performance and Private Speech of Children with Attention-Deficit/hyperactivity Disorder while Taking the Tower of Hanoi Test: Effects of Depth of Search, Diagnostic Subtype, and Methylphenidate

    ERIC Educational Resources Information Center

    Kopecky, Helena; Chang, H. Theresa; Klorman, Rafael; Thatcher, Joan E.; Borgstedt, Agneta D.

    2005-01-01

    We administered the Tower of Hanoi to demographically comparable samples of control participants (n = 34) and children with the Combined (n = 22) and Inattentive subtypes (n = 19) of Attention-Deficit/Hyperactivity Disorder (ADHD). Controls excelled over children with the Inattentive subtype, who outperformed patients with the Combined subtype.…

  6. Evaluation of the performance characteristics of the European Lightning Detection Network EUCLID in the Alps region for upward negative flashes using direct measurements at the instrumented Säntis Tower

    NASA Astrophysics Data System (ADS)

    Azadifar, Mohammad; Rachidi, Farhad; Rubinstein, Marcos; Paolone, Mario; Diendorfer, Gerhard; Pichler, Hannes; Schulz, Wolfgang; Pavanello, Davide; Romero, Carlos

    2016-01-01

    In this paper, we present a performance analysis of the European Cooperation for Lightning Detection (EUCLID) lightning detection network using data obtained on lightning currents measured at the Säntis Tower (located in northeastern of Switzerland) from June 2010 to December 2013. In the considered period of analysis, a total number of 269 upward negative flashes were recorded at the Säntis Tower. The performance of the EUCLID lightning detection network is evaluated in terms of detection efficiency, location accuracy, and peak current estimates for upward flashes. Excluding flashes containing only an initial continuous current with no superimposed pulses exceeding 2 kA, the flash detection efficiency for upward flashes is estimated to be 97%. The recorded flashes contained a total of 2795 pulses (including return strokes and International Conference on Communications pulses characterized by risetimes lower than 8 µs and peaks greater than 2 kA). The overall pulse detection efficiency was found to be 73%. For pulses with peak values higher than 5 kA, the pulse detection efficiency was found to be about 83%. Peak current estimates provided by the EUCLID network were found to be significantly larger than their directly measured counterparts. This overestimation might be attributed to the enhancement of the radiated electromagnetic fields associated with the presence of the tower and the mountain. The median of the absolute distance error, defined as the median distance between the Säntis Tower location and the EUCLID's stroke locations, was found to be 186 m, the majority of large location errors being associated with measured current peaks lower than 10 kA. The analysis revealed also that the location accuracy of the EUCLID network improved significantly in 2013 as a result of an upgrade in the location algorithms to take into account propagation effects.

  7. 5. VIEW EAST, height finder radar towers, radar tower (unknown ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW EAST, height finder radar towers, radar tower (unknown function), prime search radar tower, operations building, and central heating plant - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  8. ON THE STRUCTURE AND STABILITY OF MAGNETIC TOWER JETS

    SciTech Connect

    Huarte-Espinosa, M.; Frank, A.; Blackman, E. G.; Ciardi, A.; Hartigan, P.; Lebedev, S. V.; Chittenden, J. P.

    2012-09-20

    Modern theoretical models of astrophysical jets combine accretion, rotation, and magnetic fields to launch and collimate supersonic flows from a central source. Near the source, magnetic field strengths must be large enough to collimate the jet requiring that the Poynting flux exceeds the kinetic energy flux. The extent to which the Poynting flux dominates kinetic energy flux at large distances from the engine distinguishes two classes of models. In magneto-centrifugal launch models, magnetic fields dominate only at scales {approx}< 100 engine radii, after which the jets become hydrodynamically dominated (HD). By contrast, in Poynting flux dominated (PFD) magnetic tower models, the field dominates even out to much larger scales. To compare the large distance propagation differences of these two paradigms, we perform three-dimensional ideal magnetohydrodynamic adaptive mesh refinement simulations of both HD and PFD stellar jets formed via the same energy flux. We also compare how thermal energy losses and rotation of the jet base affects the stability in these jets. For the conditions described, we show that PFD and HD exhibit observationally distinguishable features: PFD jets are lighter, slower, and less stable than HD jets. Unlike HD jets, PFD jets develop current-driven instabilities that are exacerbated as cooling and rotation increase, resulting in jets that are clumpier than those in the HD limit. Our PFD jet simulations also resemble the magnetic towers that have been recently created in laboratory astrophysical jet experiments.

  9. The TALE Tower Detector

    NASA Astrophysics Data System (ADS)

    Bergman, D. R.

    The TA Low Energy Extension will include a Tower FluorescenceDetector. Extensive air showers at the lowest usful energies for fluorescence detectors will in general be close to the detector. This requires viewing all elevation angles to be able to reconstruct showers. The TALE Tower Detector, operating in conjunction with other TALE detectors will view elevation angles up to above 70 degrees, with an azimuthal coverage of about 90 degrees. Results from a prototype mirror operated in conjunction with the HiRes detector will also be presented.

  10. Solar thermal power towers

    NASA Astrophysics Data System (ADS)

    Kreith, F.; Meyer, R. T.

    1984-07-01

    The solar thermal central receiver technology, known as solar power towers, is rapidly evolving to a state of near-term energy availability for electrical power generation and industrial process heat applications. The systems consist of field arrays of heliostat reflectors, a central receiver boiler, short term thermal storage devices, and either turbine-generators or heat exchangers. Fluid temperatures up to 550 C are currently achievable, and technology developments are underway to reach 1100 C. Six solar power towers are now under construction or in test operation in five countries around the world.

  11. Improve vacuum-tower performance

    SciTech Connect

    Kister, H.Z.; Rhoad, R.; Hoyt, K.A.

    1996-09-01

    There is much talk today about an expert system that will be able to start up and operate distillation columns painlessly, effortlessly, and in a trouble-free manner. Until that expert system arrives, however, startup and initial operation of distillation columns will continue to present challenging problems, and solving these problems will continue to consume effort, money, and sleepless nights. The objective of this article is to make several experiences, gained in the school of hard knocks, available to troubleshooters. Traditionally, such experiences have provided the most powerful tool for solving today`s problems and avoiding tomorrow`s. When eventually an expert system does take over, these experiences are likely to provide it with a well from which it can draw its expertise.

  12. High-performance and long-range cooled IR technologies in France

    NASA Astrophysics Data System (ADS)

    Reibel, Yann; Augey, Thibault; Verdet, Sebastien; Maillart, Patrick; Rubaldo, Laurent; Billon-Lanfrey, David; Mollard, Laurent; Marion, François; Baier, Nicolas; Destefanis, Gérard

    2013-06-01

    Cooled IR technologies that offer high performances are at the top of DEFIR's priority list. We have been pursuing further infrared developments on future MWIR detectors, such as the VGA format HOT detector that operates at 150K and the 10μm pitch IR detector which gives us a leading position in innovation In the same time Scorpio LW expands Sofradir's line of small pixel pitch TV format IR detectors from the mid-wavelength to the long-wavelength, broadening the performance attributes of its long wave IR product line. Finally, our dual band MW-LW QWIP detectors (25μm, 384×288 pixels) benefit to tactical platforms giving an all-weather performance and increasing flexibility in the presence of battlefield obscurants. These detectors are designed for long-range surveillance equipment, commander or gunner sights, ground-toground missile launchers and other applications that require higher resolution and sensitivity to improve reconnaissance and target identification. This paper discusses the system level performance in each detector type.

  13. Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion.

    PubMed

    Cornejo, J M; Colombano, M; Doménech, J; Block, M; Delahaye, P; Rodríguez, D

    2015-10-01

    A special ion trap was initially built up to perform β-ν correlation experiments with radioactive ions. The trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single (40)Ca(+) ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on (40)Ca(+) ions, starting from large clouds and reaching single ion sensitivity. This new feature of the trap might be important also for other experiments with ions produced at radioactive ion beam facilities. In this publication, the trap and the laser system will be described, together with their performance with respect to laser cooling applied to large ion clouds down to a single ion.

  14. Performance evaluation of radiant cooling system integrated with air system under different operational strategies

    SciTech Connect

    Khan, Yasin; Khare, Vaibhav Rai; Mathur, Jyotirmay; Bhandari, Mahabir

    2015-03-26

    The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building using a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.

  15. Performance evaluation of radiant cooling system integrated with air system under different operational strategies

    DOE PAGES

    Khan, Yasin; Khare, Vaibhav Rai; Mathur, Jyotirmay; Bhandari, Mahabir

    2015-03-26

    The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building usingmore » a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.« less

  16. Ivory Basements and Ivory Towers

    ERIC Educational Resources Information Center

    Fitzgerald, Tanya

    2012-01-01

    The metaphors of the ivory tower and ivory basement are used in this chapter to reflect how many women understand and experience the academy. The ivory tower signifies a place that is protected, a place of privilege and authority and a place removed from the outside world (and consequently the rigours of the market place). The ivory tower, by…

  17. Effect of pulse tube volume on dynamics of linear compressor and cooling performance in Stirling-type pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Ko, Junseok; Jeong, Sangkwon; Ki, Taekyoung

    2010-01-01

    In a Stirling-type pulse tube refrigerator (PTR), the pulse tube volume affects the dynamic behavior of a linear compressor as well as the cooling performance of PTR. In this study, PTRs which have different pulse tube volume are tested and simulated. The simulation code is verified with the experimental measurement of piston displacement, pressure wave, input power and cooling capacity. And then, the power transfer from the electric power input to the cooling capacity is explained with the simulation results. The smaller pulse tube increases the resonant frequency of a linear compressor and suppresses the piston motion because it imposes larger gas spring effect and also larger gas damping effect to the piston. The smaller one allows larger power transfer from electric power to expansion PV work despite the smaller piston displacement, but shows less cooling capacity due to larger thermal losses.

  18. Windmill tower shadow eliminator

    SciTech Connect

    Randolph, A.J.

    1984-04-17

    In a wind driven propeller system an airfoil support for the shaft of a propeller having an even number of blades extends above and below the shaft a distance at least equal to the blade length and pivots with the propeller into the wind for substantially eliminating tower shadow effects on the propeller.

  19. Cell Towers and Songbirds

    ERIC Educational Resources Information Center

    Klosterman, Michelle; Mesa, Jennifer; Milton, Katie

    2009-01-01

    This article describes how our common addiction to cell phones was used to launch a discussion about their use, impacts on the environment, and connections to issues of civic concern. By encouraging middle school science students to adopt the perspectives of special-interest groups debating communication tower restrictions designed to protect…

  20. The Ivory Tower Revisited

    ERIC Educational Resources Information Center

    Chantler, Abigail

    2016-01-01

    The corollary of the concept of the "ivory tower", as reflected in the writings of Plato and Newman amongst others, was, paradoxically, the vital importance of the university for wider society. Nevertheless from the mid-twentieth century, the esteem in which a "liberal" university education was held was diminished by rising…

  1. The Towers of Hanoi

    ERIC Educational Resources Information Center

    Morris, George C.

    2007-01-01

    This article presents an investigation carried out with a group of able mathematics students who were studying at a level 1 year in advance of their peers. The purpose was to investigate the extension of usual three peg Towers of Hanoi to four pegs and attempt to find a rule that could be used to predict the minimum number of moves required to…

  2. Isothermal Adsorption Measurement for the Development of High Performance Solid Sorption Cooling System

    NASA Astrophysics Data System (ADS)

    Saha, Bidyut Baran; Koyama, Shigeru; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao; Ng, Kim Choon; Chua, Hui Tong

    Interest in low-grade thermal heat powered solid sorption system using natural refrigerants has been increased. However, the drawbacks of these adsorption systems are their poor performance. The objective of this paper is to improve the performance of thermally powered adsorption cooling system by selecting new adsorbent-refrigerant pairs. Adsorption capacity of adsorbent-refrigerant pair depends on the thermophysical properties (pore size, pore volume and pore diameter) of adsorbent and isothermal characteristics of the adsorbent-refrigerant pair. In this paper, the thermophysical properties of three types of silica gels and three types of pitch based activated carbon fibers are determined from the nitrogen adsorption isotherms. The standard nitrogen gas adsorption/desorption measurements on various adsorbents at liquid nitrogen of temperature 77.4 K were performed. Surface area of each adsorbent was determined by the Brunauer, Emmett and Teller (BET) plot of nitrogen adsorption data. Pore size distribution was measured by the Horvath and Kawazoe (HK) method. Adsorption/desorption isotherm results showed that all three carbon fibers have no hysteresis and had better adsorption capacity in comparison with those of silica gels.

  3. Optimum dry-cooling sub-systems for a solar air conditioner

    NASA Technical Reports Server (NTRS)

    Chen, J. L. S.; Namkoong, D.

    1978-01-01

    Dry-cooling sub-systems for residential solar powered Rankine compression air conditioners were economically optimized and compared with the cost of a wet cooling tower. Results in terms of yearly incremental busbar cost due to the use of dry-cooling were presented for Philadelphia and Miami. With input data corresponding to local weather, energy rate and capital costs, condenser surface designs and performance, the computerized optimization program yields design specifications of the sub-system which has the lowest annual incremental cost.

  4. Methodology to determine cost and performance goals for active solar cooling systems

    NASA Astrophysics Data System (ADS)

    Warren, M. L.; Wahlig, M.

    1981-11-01

    Systems analysis is used to calculate the 20 yr. present value of energy savings of solar cooling systems located in Texas, Arizona, Florida, and Washington, DC, and methods of solar system development to meet the cost goals of economic operation are outlined. Solar cooling systems are projected to begin commercial entry in 1986 and reach 20% of the total cooling market by the year 2000, producing 0.14 quads of displaced energy. A numerical simulation was carried out for both residential and commercial solar cooling units with consideration for system cost goals, cost goals per unit collector area, and the cost goals per ton of cooling. System size was targeted as a 3 ton residential chiller and a 25 ton commercial absorption cooling unit. The costs for volume production are provided, along with trends for an incrementally decreasing need for tax incentives, ending in about 1994

  5. Cold air performance of a 12.766-centimeter-tip-diameter axial-flow cooled turbine. 2: Effect of air ejection on turbine performance

    NASA Technical Reports Server (NTRS)

    Haas, J. E.; Kofskey, M. G.

    1977-01-01

    An air cooled version of a single-stage, axial-flow turbine was investigated to determine aerodynamic performance with and without air ejection from the stator and rotor blades surfaces to simulate the effect of cooling air discharge. Air ejection rate was varied from 0 to 10 percent of turbine mass flow for both the stator and the rotor. A primary-to-air ejection temperature ratio of about 1 was maintained.

  6. Interim Report: Air-Cooled Condensers for Next Generation Geothermal Power Plants Improved Binary Cycle Performance

    SciTech Connect

    Daniel S. Wendt; Greg L. Mines

    2010-09-01

    As geothermal resources that are more expensive to develop are utilized for power generation, there will be increased incentive to use more efficient power plants. This is expected to be the case with Enhanced Geothermal System (EGS) resources. These resources will likely require wells drilled to depths greater than encountered with hydrothermal resources, and will have the added costs for stimulation to create the subsurface reservoir. It is postulated that plants generating power from these resources will likely utilize the binary cycle technology where heat is rejected sensibly to the ambient. The consumptive use of a portion of the produced geothermal fluid for evaporative heat rejection in the conventional flash-steam conversion cycle is likely to preclude its use with EGS resources. This will be especially true in those areas where there is a high demand for finite supplies of water. Though they have no consumptive use of water, using air-cooling systems for heat rejection has disadvantages. These systems have higher capital costs, reduced power output (heat is rejected at the higher dry-bulb temperature), increased parasitics (fan power), and greater variability in power generation on both a diurnal and annual basis (larger variation in the dry-bulb temperature). This is an interim report for the task ‘Air-Cooled Condensers in Next- Generation Conversion Systems’. The work performed was specifically aimed at a plant that uses commercially available binary cycle technologies with an EGS resource. Concepts were evaluated that have the potential to increase performance, lower cost, or mitigate the adverse effects of off-design operation. The impact on both cost and performance were determined for the concepts considered, and the scenarios identified where a particular concept is best suited. Most, but not all, of the concepts evaluated are associated with the rejection of heat. This report specifically addresses three of the concepts evaluated: the use of

  7. Effect of Material Inhomogeneity on Thermal Performance of a Rheocast Aluminum Heatsink for Electronics Cooling

    NASA Astrophysics Data System (ADS)

    Payandeh, M.; Belov, I.; Jarfors, A. E. W.; Wessén, M.

    2016-06-01

    The relation between microstructural inhomogeneity and thermal conductivity of a rheocast component manufactured from two different aluminum alloys was investigated. The formation of two different primary α-Al particles was observed and related to multistage solidification process during slurry preparation and die cavity filling process. The microstructural inhomogeneity of the component was quantified as the fraction of α 1-Al particles in the primary Al phase. A high fraction of coarse solute-lean α 1-Al particles in the primary Al phase caused a higher thermal conductivity of the component in the near-to-gate region. A variation in thermal conductivity through the rheocast component of 10% was discovered. The effect of an inhomogeneous temperature-dependent thermal conductivity on the thermal performance of a large rheocast heatsink for electronics cooling in an operation environment was studied by means of simulation. Design guidelines were developed to account for the thermal performance of heatsinks with inhomogeneous thermal conductivity, as caused by the rheocasting process. Under the modeling assumptions, the simulation results showed over 2.5% improvement in heatsink thermal resistance when the higher conductivity near-to-gate region was located at the top of the heatsink. Assuming homogeneous thermo-physical properties in a rheocast heatsink may lead to greater than 3.5% error in the estimation of maximum thermal resistance of the heatsink. The variation in thermal conductivity within a large rheocast heatsink was found to be important for obtaining of a robust component design.

  8. Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

    SciTech Connect

    Haaf, G. ten; Wouters, S. H. W.; Vredenbregt, E. J. D.; Mutsaers, P. H. A.; Geer, S. B. van der

    2014-12-28

    Focused ion beams are indispensable tools in the semiconductor industry because of their ability to image and modify structures at the nanometer length scale. Here, we report on performance predictions of a new type of focused ion beam based on photo-ionization of a laser cooled and compressed atomic beam. Particle tracing simulations are performed to investigate the effects of disorder-induced heating after ionization in a large electric field. They lead to a constraint on this electric field strength which is used as input for an analytical model which predicts the minimum attainable spot size as a function of, amongst others, the flux density of the atomic beam, the temperature of this beam, and the total current. At low currents (I < 10 pA), the spot size will be limited by a combination of spherical aberration and brightness, while at higher currents, this is a combination of chromatic aberration and brightness. It is expected that a nanometer size spot is possible at a current of 1 pA. The analytical model was verified with particle tracing simulations of a complete focused ion beam setup. A genetic algorithm was used to find the optimum acceleration electric field as a function of the current. At low currents, the result agrees well with the analytical model, while at higher currents, the spot sizes found are even lower due to effects that are not taken into account in the analytical model.

  9. The Drop Tower Bremen -An Overview

    NASA Astrophysics Data System (ADS)

    von Kampen, Peter; Könemann, Thorben; Rath, Hans J.

    The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University of Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of ZARM`s drop tower began. Since its inau-guration in September 1990, the eye-catching Drop Tower Bremen with a height of 146m and its characteristic glass roof has become twice a landmark on the campus of the University of Bremen and the emblem of the technology park Bremen. As such an outstanding symbol of space science in Bremen the drop tower provides an european unique facility for experiments under conditions of high-quality weightlessness with residual gravitational accelerations in the microgravity regime. The period of maximum 4.74s of each freely falling experiment at the Drop Tower Bremen is only limited by the height of the drop tower vacuum tube, which was fully manufactured of steal and enclosed by an outer concrete shell. Thus, the pure free fall height of each microgravity drop experiment is approximately 110m. By using the later in-stalled catapult system established in 2004 ZARM`s short-term microgravity laboratory is able to nearly double the time of free fall. This world-wide inimitable capsule catapult system meets scientists` demand of extending the period of weightlessness. During the catapult operation the experiment capsule performs a vertical parabolic flight within the drop tower vacuum tube. In this way the time of microgravity can be extended to slightly over 9s. Either in the drop or in the catapult operation routine the repetition rates of microgravity experiments at ZARM`s drop tower facility are the same, generally up to 3 times per day. In comparison to orbital platforms the ground-based laboratory Drop Tower Bremen represents an economic alternative with a permanent access to weightlessness on earth. Moreover, the exceptional high quality of weightlessness in order of 1e-6 g (in the frequency range below 100

  10. Design and performance of cooled perches for alternative egg laying production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heat stress in both mechanically and naturally ventilated egg production facilities is a problem for the egg industry. Various means of providing supplemental cooling to hens in facilities are available, including tunnel ventilation to increase convective losses and evaporative cooling from either p...

  11. Performance of vegetable oils as a cooling medium in comparison to a standard mineral oil

    NASA Astrophysics Data System (ADS)

    Totten, G. E.; Tensi, H. M.; Lainer, K.

    1999-08-01

    Immersion quenching is the most widely used quenching technique today and is usually one of the last steps in heat treat processing. Improper hardening to incorrect cooling is generally a great loss and causes a great percentage of manufacturing costs. To avoid a failure in cooling, researchers are committed to describing the cooling effect as precisely as possible. The cooling of immersion cooled workpieces or probes is generally characterized by the process of wetting. Evaporable fluids exhibit the three well known stages of cooling: vapor blanket stage, boiling stage, and convective heat transfer. Therefore cooling behavior is influenced by a wide variety and depends on a number of parameters, that is, type of quenchant used, bath temperature, rate of agitation, and the physical and chemical properties of the quenched parts. Environmental pollution has caused the search for new products in har dening and shock cooling of steels. The use of soybean oils as quenching fluids is new, and compared with standard mineral oils, there are many advantages mainly concerning the environment and the health of workers.

  12. Assessing the performance of Clostridium perfringens cooling models for cooked, uncured meat and poultry products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heat-resistant spores of C. perfringens may germinate and multiply in cooked meat and poultry products if the rate and extent of cooling does not occur in a timely manner. Therefore, six cooling models (PMP 7.0 broth model; PMIP Uncured Beef, Chicken, and Pork Models; Smith-Schaffner (version 3); a...

  13. Aerodynamic performance of a fully film cooled core turbine vane tested with cold air in a two-dimensional cascade

    NASA Technical Reports Server (NTRS)

    Stabe, R. G.; Kline, J. F.

    1975-01-01

    The aerodynamic performance of a fully film cooled core turbine vane was investigated experimentally in a two-dimensional cascade of 10 vanes. Three of the 10 vanes were cooled; the others were solid (uncooled) vanes. Cold air was used for both the primary and coolant flows. The cascade test covered a range of pressure ratios corresponding to ideal exit critical velocity ratios of 0.6 to 0.95 and a range of coolant flow rates to 7.5 percent of the primary flow. The coolant flow was varied by changing the coolant supply pressure. The principal measurements were cross-channel surveys of exit total pressure, static pressure, and flow angle. The results presented include exit survey data and overall performance in terms of loss, flow angle, and weight flow for the range of exit velocity ratios and coolant flows investigated. The performance of the cooled vane is compared with the performance of an uncooled vane of the same profile and also with the performance obtained with a single cooled vane in the 10-vane cascade.

  14. Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

    NASA Astrophysics Data System (ADS)

    Afshari, Ebrahim; Ziaei-Rad, Masoud; Jahantigh, Nabi

    2016-06-01

    In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.

  15. Successfully troubleshoot distillation towers

    SciTech Connect

    Hasbrouck, J.F. ); Kunesh, J.G. ); Smith, V.C. )

    1993-03-01

    Distillation dominates separation services in the chemical process industries. With this widespread use, not surprisingly, operating problems are common. Because distillation columns frequently are limiting factors in plant capacity or product quality, correcting these problems usually is urgent. The paper describes the steps to be taken to start to correct problems on distillation towers: understand the ground rules, understand the people and procedures, and understand the plant. Then observe the actual operation, monitor the system, collect required data, and analyze the data. The paper discusses how to determine the problem area, broadening the search, focusing on the distillation tower and its internals, confirming the specific problem, extending the troubleshooting activities, and dealing with tougher problems.

  16. The performance of a solar-regenerated open-cycle desiccant bed grain cooling system

    SciTech Connect

    Ismail, M.Z.; Angus, D.E. ); Thorpe, G.R. )

    1991-01-01

    The cooling of stored food grains suppresses the growth of populations of insect pests, inhibits spoilage by fungi and helps to preserve grain quality. In temperate and subtropical climates, grains may be effectively cooled by ventilating them with ambient air. In tropical climates, the enthalpy of the air must be reduced before it can be used for cooling grain. One method of achieving this is to isothermally reduce the humidity of the air. This paper describes experiments carried out on a simple-to-build solar-regenerated open-cycle grain cooling system. The device consists of a 5.85 m{sup 2} collector coupled with two beds of silica gel. Results from a series of experiments suggest that the device may be used to cool up to 200 tons of grain. The electrical power consumption of the device is of the order of 0.3 watt per ton of grain cooled, and the total electrical energy consumption is of the order of 0.7 kWh per ton of grain stored for a six-month period. The effectiveness of the device is a function of air flow rate and the enthalpy of ambient air, and results presented in this paper suggest that the solar cooling device is particularly effective in tropical climates.

  17. Thermal-hydraulic analysis of N Reactor graphite and shield cooling system performance

    SciTech Connect

    Low, J.O.; Schmitt, B.E.

    1988-02-01

    A series of bounding (worst-case) calculations were performed using a detailed hydrodynamic RELAP5 model of the N Reactor graphite and shield cooling system (GSCS). These calculations were specifically aimed to answer issues raised by the Westinghouse Independent Safety Review (WISR) committee. These questions address the operability of the GSCS during a worst-case degraded-core accident that requires the GDCS to mitigate the consequences of the accident. An accident scenario previously developed was designed as the hydrogen-mitigation design-basis accident (HMDBA). Previous HMDBA heat transfer analysis,, using the TRUMP-BD code, was used to define the thermal boundary conditions that the GSDS may be exposed to. These TRUMP/HMDBA analysis results were used to define the bounding operating conditions of the GSCS during the course of an HMDBA transient. Nominal and degraded GSCS scenarios were investigated using RELAP5 within or at the bounds of the HMDBA transient. 10 refs., 42 figs., 10 tabs.

  18. Comparison of Oxidation Stability and Quenchant Cooling Curve Performance of Soybean Oil and Palm Oil

    NASA Astrophysics Data System (ADS)

    Said, Diego; Belinato, Gabriela; Sarmiento, Gustavo S.; Otero, Rosa L. Simencio; Totten, George E.; Gastón, Analía; Canale, Lauralice C. F.

    2013-07-01

    The potential use of vegetable oil-derived industrial oils continues to be of great interest because vegetable oils are relatively non-toxic, biodegradable, and they are a renewable basestock alternative to petroleum oil. However, the fatty ester components containing conjugated double bonds of the triglyceride structure of vegetable oils typically produce considerably poorer thermal-oxidative stability than that achievable with petroleum basestocks under typical use conditions. Typically, these conditions involve furnace loads of hot steel (850 °C), which are rapidly immersed and cooled to bath temperatures of approximately 50-60 °C. This is especially true when a vegetable oil is held in an open tank with agitation and exposed to air at elevated temperatures for extended periods of time (months or years). This paper will describe the thermal-oxidative stability and quenching performance of soybean oil and palm oil and the resulting impact on the heat transfer coefficient. These results are compared to typical fully formulated, commercially available accelerated (fast) and an unaccelerated (slow) petroleum oil-based quenchants.

  19. Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists.

    PubMed

    Karlsen, A; Racinais, S; Jensen, M V; Nørgaard, S J; Bonne, T; Nybo, L

    2015-06-01

    This study investigated if well-trained cyclists improve V ˙ O 2 m a x and performance in cool conditions following heat acclimatization through natural outdoor training in hot conditions. Eighteen trained male cyclists were tested for physiological adaptations, V ˙ O 2 m a x , peak aerobic power output, exercise efficiency, and outdoor time trial (TT) performance (43.4 km in cool environment, ∼5-13 °C) before and after 2 weeks of training in a cool (CON, n = 9) or hot (∼35 °C, HA, n = 9) environment. After heat acclimatization, TT performance in the heat was improved by 16%; however, there was no change in the HA group in V ˙ O 2 m a x (4.79 ± 0.21 L/min vs 4.82 ± 0.35 L/min), peak aerobic power output (417 ± 16 W vs 422 ± 17 W), and outdoor TT performance in cool conditions (300 ± 14 W/69 ± 3 min vs 302 ± 9 W/69 ± 4 min). The present study shows that 2 weeks of heat acclimatization was associated with marked improvements in TT performance in the heat. However, for the well-trained endurance athletes, this did not transfer to an improved aerobic exercise capacity or outdoor TT performance in cool conditions.

  20. Thermal Hydraulic Analysis of an Experimental Reactor Cavity Cooling System with Water: Performance and Stability

    NASA Astrophysics Data System (ADS)

    Lisowski, Darius D.

    This experimental study investigated the thermal hydraulic behavior and boiling mechanisms present in a scaled reactor cavity cooling system (RCCS). The experimental facility reflects a ¼ scale model of one conceptual design for decay heat removal in advanced GenIV nuclear reactors. Radiant heaters supply up to 25 kW/m2 onto a three parallel riser tube and cooling panel test section assembly, representative of a 5° sector model of the full scale concept. Derived similarity relations have preserved the thermal hydraulic flow patterns and integral system response, ensuring relevant data and similarity among scales. Attention will first be given to the characterization of design features, form and heat losses, nominal behavior, repeatability, and data uncertainty. Then, tests performed in single-phase have evaluated the steady-state behavior. Following, the transition to saturation and subsequent boiling allowed investigations onto four parametric effects at two-phase flow and will be the primary focus area of remaining analysis. Baseline conditions at two-phase flow were defined by 15.19 kW of heated power and 80% coolant inventory, and resulted in semi-periodic system oscillations by the mechanism of hydrostatic head fluctuations. Void generation was the result of adiabatic expansion of the fluid due to a reduction in hydrostatic head pressure, a phenomena similar to flashing. At higher powers of 17.84 and 20.49 kW, this effect was augmented, creating large flow excursions that followed a smooth and sinusoidal shaped path. Stabilization can occur if the steam outflow condition incorporates a nominal restriction, as it will serve to buffer the short time scale excursions of the gas space pressure and dampen oscillations. The influences of an inlet restriction, imposed by an orifice plate, introduced subcooling boiling within the heated core and resulted in chaotic interactions among the parallel risers. The penultimate parametric examined effects of boil-off and

  1. Cross-flow versus counterflow air-stripping towers

    SciTech Connect

    Little, J.C.; Marinas, B.J.

    1997-07-01

    Mass-transfer and pressure-drop packing performance correlations are used together with tower design equations and detailed cost models to compare the effectiveness of cross-flow and counterflow air stripping towers over a wide range of contaminant volatility. Cross-flow towers are shown to offer a significant economic advantage over counterflow towers when stripping low volatility organic contaminants primarily due to savings in energy costs. These savings increase as contaminant volatility decreases and as water flow rate increases. A further advantage of the cross-flow configuration is that it extends the feasible operating range for air stripping as cross-flow towers can accommodate higher air-to-water flow ratios than conventional counterflow towers. Finally it is shown that the optimized least-cost design for both counterflow and cross-flow towers varies with Henry`s law constant, water flow rate, and percent removal, but that the optimum is virtually insensitive to other cost and operating variables. This greatly simplifies the tower design procedure.

  2. Establish feasibility for providing passive cooling with solar updraft and evaporate downdraft chimneys

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.; Thompson, T.L.

    1987-01-01

    Natural draft towers can be used for cooling and ventilating structures. From an operational perspective, the downdraft evaporatively cooled tower is preferred for a dry climate. Solar chimneys, when used alone, tend to require an excessively large solar collector area when appreciable quantities of air must be moved. When used in combination with a downdraft tower, the roof and attic of buildings may assist the solar chimney and their use becomes more attractive. Both a frame building and a greenhouse were successfully cooled during this program. The economics of the downdraft tower compare favorably with conventional evaporative cooling for some applications.

  3. Establish feasibility for providing passive cooling with solar updraft and evaporative downdraft chimneys

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.; Thompson, T.L.

    1987-01-01

    Natural draft towers can be used for cooling and ventilating structures. From an operational perspective, the downdraft evaporatively cooled tower is preferred for a dry climate. Solar chimneys, when used alone, tend to require an excessively large solar collector area when appreciable quantities of air must be moved. When used in combination with a downdraft tower, the roof and attic of buildings may assist the solar chimney and their use becomes more attractive. Both a frame building and a greenhouse were successfully cooled during this program. The economics of the downdraft tower compare favorably with conventional evaporative cooling for some application.

  4. Performance of water jet cooled silicon monochromators in high power x-ray beams (abstract)

    NASA Astrophysics Data System (ADS)

    Berman, Lonny E.; Hart, Michael

    1992-01-01

    beam footprint were undertaken.3 For the line power loading situation, Bragg angle variations of up to 4 arcsec across the beam footprint were observed, resulting in near-perfect performance for the fundamental.4 The harmonic was more sensitive to these strains;4 the described adaptive methods were used to correct for them.5 For the point loading situation, Bragg angle variations of over 200 arcsec were measured, causing distorted fundamental and harmonic reflectivity curves; again, ≳90% compensation was achieved via adaptive techniques.6 The detailed results show that while, for silicon at room temperature, passive crystal cooling methods are sufficient for the present unfocused insertion device beam lines, adaptive methods will have to be considered for future insertion device beam lines. This work was supported in part by th

  5. Is performance of intermittent intense exercise enhanced by use of a commercial palm cooling device?

    PubMed

    Walker, Thomas B; Zupan, Michael F; McGregor, Julia N; Cantwell, Andrew R; Norris, Torrance D

    2009-12-01

    The purpose of this study was to determine if using the CoreControl Rapid Thermal Exchange (RTX), a commercial palm cooling device, during active rest periods of multiple set training is an effective means to increase performance. Ten volunteers (5 men, 5 women) completed a VO2max test on a motorized treadmill and 3 interval running tests on a human powered treadmill. This treadmill allowed the subjects to quickly reach their running speed while allowing for measurement of distance, speed, and force. During the interval running tests the subjects completed eight 30-second intervals at a hard/fast pace followed by a 90-second walking or light jogging recovery period. During the recovery period, the subjects placed their left hand on 1 of 3 media: the RTX held at 15 degrees C (R), a 15 degrees C standard refrigerant gel pack (P), or nothing at all (C). Although there were differences in core temperature (Tc), subjective heat stress ratings, distance, and power generated between intervals, there were no significant differences (p < 0.05) found between treatments for any of these variables, nor was the interaction effect of interval*treatment found to be significant. Mean distance completed per trial was 717.1 m +/- 124.4 m (R), 724.8 m +/- 130.3 m (P), and 728.6 m +/- 110.6 m (C). Change in Tc from baseline to end-test averaged 1.41 degrees C +/- 0.37 degrees C (R), 1.41 degrees C +/- 0.39 degrees C (P), and 1.41 degrees C +/- 0.59 degrees C (C). There were no significant differences (p < 0.05) in Tc, heart rate (HR), or VO2 between intervals or treatments. We conclude that the RTX, in its current iteration, is ineffective at improving performance and/or mitigating thermal stress during high-intensity intermittent exercise. PMID:19910808

  6. Aerosol Effects on Radiation and Climate: Column Closure Experiments with Towers, Aircraft, and Satellites

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.

    1994-01-01

    Many theoretical studies have shown that anthropogenic aerosol particles can change the radiation balance in an atmospheric column and might thereby exert a significant effect on the Earth's climate. In particular, recent calculations have shown that sulfate particles from anthropogenic combustion may already exert a cooling influence on the Earth that partially offsets the warming caused by the greenhouse gases from the same combustion. Despite the potential climatic importance of anthropogenic aerosols, simultaneous measurements of anthropogenic aerosol properties and their effect on atmospheric radiation have been very rare. Successful comparisons of measured radiation fields with those calculated from aerosol measurements - now referred to as column closure comparisons - are required to improve the accuracy and credibility of climate predictions. This paper reviews the column closure experiment performed at the Mt. Sutro Tower in San Francisco in 1975, in which elevated radiometers measured the change in Earth-plus-atmosphere albedo caused by an aerosol layer, while a lidar, sunphotometer, nephelometer, and other radiometers measured properties of the responsible aerosol. The time-dependent albedo calculated from the measured aerosol properties agreed with that measured by the tower radiometers. Also presented are designs for future column closure studies using radiometers and aerosol instruments on the ground, aircraft, and satellites. These designs draw upon algorithms and experience developed in the Sutro Tower study, as well as more recent experience with current measurement and analysis capabilities.

  7. Evaluation of the NightCool Nocturnal Radiation Cooling Concept: Annual Performance Assessment in Scale Test Buildings Stage Gate 1B

    SciTech Connect

    Parker, Danny S.; Sherwin, John R.

    2008-03-01

    In this report, data is presented on the long-term comparative with all of NightCool system fully operational, with circulating fans when attic conditions are favorable for nocturnal cooling and with conventional air conditioning at other times. Data is included for a full year of the cooling season in Central Florida, which stretches from April to November of 2007.

  8. Experimental study of high-performance cooling system pipeline diameter and working fluid amount

    NASA Astrophysics Data System (ADS)

    Nemec, Patrik; Malcho, Milan; Hrabovsky, Peter; Papučík, Štefan

    2016-03-01

    This work deals with heat transfer resulting from the operation of power electronic components. Heat is removed from the mounting plate, which is the evaporator of the loop thermosyphon to the condenser and by natural convection is transferred to ambient. This work includes proposal of cooling device - loop thermosyphon, with its construct and follow optimization of cooling effect. Optimization proceeds by selecting the quantity of working fluid and selection of diameters vapour line and liquid line of loop thermosyphon.

  9. Implications of Transitioning from De Facto to Engineered Water Reuse for Power Plant Cooling.

    PubMed

    Barker, Zachary A; Stillwell, Ashlynn S

    2016-05-17

    Thermoelectric power plants demand large quantities of cooling water, and can use alternative sources like treated wastewater (reclaimed water); however, such alternatives generate many uncertainties. De facto water reuse, or the incidental presence of wastewater effluent in a water source, is common at power plants, representing baseline conditions. In many cases, power plants would retrofit open-loop systems to cooling towers to use reclaimed water. To evaluate the feasibility of reclaimed water use, we compared hydrologic and economic conditions at power plants under three scenarios: quantified de facto reuse, de facto reuse with cooling tower retrofits, and modeled engineered reuse conditions. We created a genetic algorithm to estimate costs and model optimal conditions. To assess power plant performance, we evaluated reliability metrics for thermal variances and generation capacity loss as a function of water temperature. Applying our analysis to the greater Chicago area, we observed high de facto reuse for some power plants and substantial costs for retrofitting to use reclaimed water. Conversely, the gains in reliability and performance through engineered reuse with cooling towers outweighed the energy investment in reclaimed water pumping. Our analysis yields quantitative results of reclaimed water feasibility and can inform sustainable management of water and energy.

  10. Implications of Transitioning from De Facto to Engineered Water Reuse for Power Plant Cooling.

    PubMed

    Barker, Zachary A; Stillwell, Ashlynn S

    2016-05-17

    Thermoelectric power plants demand large quantities of cooling water, and can use alternative sources like treated wastewater (reclaimed water); however, such alternatives generate many uncertainties. De facto water reuse, or the incidental presence of wastewater effluent in a water source, is common at power plants, representing baseline conditions. In many cases, power plants would retrofit open-loop systems to cooling towers to use reclaimed water. To evaluate the feasibility of reclaimed water use, we compared hydrologic and economic conditions at power plants under three scenarios: quantified de facto reuse, de facto reuse with cooling tower retrofits, and modeled engineered reuse conditions. We created a genetic algorithm to estimate costs and model optimal conditions. To assess power plant performance, we evaluated reliability metrics for thermal variances and generation capacity loss as a function of water temperature. Applying our analysis to the greater Chicago area, we observed high de facto reuse for some power plants and substantial costs for retrofitting to use reclaimed water. Conversely, the gains in reliability and performance through engineered reuse with cooling towers outweighed the energy investment in reclaimed water pumping. Our analysis yields quantitative results of reclaimed water feasibility and can inform sustainable management of water and energy. PMID:27077957

  11. Unsteady High Turbulence Effects on Turbine Blade Film Cooling Heat Transfer Performance Using a Transient Liquid Crystal Technique

    NASA Technical Reports Server (NTRS)

    Han, J. C.; Ekkad, S. V.; Du, H.; Teng, S.

    2000-01-01

    Unsteady wake effect, with and without trailing edge ejection, on detailed heat transfer coefficient and film cooling effectiveness distributions is presented for a downstream film-cooled gas turbine blade. Tests were performed on a five-blade linear cascade at an exit Reynolds number of 5.3 x 10(exp 5). Upstream unsteady wakes were simulated using a spoke-wheel type wake generator. Coolant blowing ratio was varied from 0.4 to 1.2; air and CO2 were used as coolants to simulate different density ratios. Surface heat transfer and film effectiveness distributions were obtained using a transient liquid crystal technique; coolant temperature profiles were determined with a cold wire technique. Results show that Nusselt numbers for a film cooled blade are much higher compared to a blade without film injection. Unsteady wake slightly enhances Nusselt numbers but significantly reduces film effectiveness versus no wake cases. Nusselt numbers increase only slic,htly but film cooling, effectiveness increases significantly with increasing, blowing ratio. Higher density coolant (CO2) provides higher effectiveness at higher blowing ratios (M = 1.2) whereas lower density coolant (Air) provides higher 0 effectiveness at lower blowing ratios (M = 0.8). Trailing edge ejection generally has more effect on film effectiveness than on the heat transfer, typically reducing film effectiveness and enhancing heat transfer. Similar data is also presented for a film cooled cylindrical leading edge model.

  12. 3-Dimensional numerical study of cooling performance of a heat sink with air-water flow through mini-channel

    NASA Astrophysics Data System (ADS)

    Majumder, Sambit; Majumder, Abhik; Bhaumik, Swapan

    2016-07-01

    The present microelectronics market demands devices with high power dissipation capabilities having enhanced cooling per unit area. The drive for miniaturizing the devices to even micro level dimensions is shooting up the applied heat flux on such devices, resulting in complexity in heat transfer and cooling management. In this paper, a method of CPU processor cooling is introduced where active and passive cooling techniques are incorporated simultaneously. A heat sink consisting of fins is designed, where water flows internally through the mini-channel fins and air flows externally. Three dimensional numerical simulations are performed for large set of Reynolds number in laminar region using finite volume method for both developing flows. The dimensions of mini-channel fins are varied for several aspect ratios such as 1, 1.33, 2 and 4. Constant temperature (T) boundary condition is applied at heat sink base. Channel fluid temperature, pressure drop are analyzed to obtain best cooling option in the present study. It has been observed that as the aspect ratio of the channel decreases Nusselt number decreases while pressure drop increases. However, Nusselt number increases with increase in Reynolds number.

  13. Effects of evaporative cooling on reproductive performance and milk production of dairy cows in hot wet conditions

    NASA Astrophysics Data System (ADS)

    Khongdee, S.; Chaiyabutr, N.; Hinch, G.; Markvichitr, K.; Vajrabukka, C.

    2006-05-01

    Fourteen animals of second and third lactation of Thai Friesian crossbred cows (87.5% Friesian × 12.5% Bos indicus) located at Sakol Nakhon Research and Breeding Centre, Department of Livestock Development, Ministry of Agriculture and Cooperatives, were divided randomly into two groups of seven each to evaluate the effects of evaporative cooling on reproductive and physiological traits under hot, humid conditions. Results indicated that installation of evaporating cooling in the open shed gave a further improvement in ameliorating heat stress in dairy cows in hot-wet environments by utilising the low humidity conditions that naturally occur during the day. The cows housed in an evaporatively cooled environment had both a rectal temperature and respiration rate (39.09°C, 61.39 breaths/min, respectively) significantly lower than that of the non-cooled cows (41.21°C; 86.87 breaths/min). The former group also had higher milk yield and more efficient reproductive performance (pregnancy rate and reduced days open) than the latter group. It is suggested that the non-evaporatively cooled cows did not gain benefit from the naturally lower heat stress during night time.

  14. Optimizing X-ray mirror thermal performance using matched profile cooling

    SciTech Connect

    Zhang, Lin; Cocco, Daniele; Kelez, Nicholas; Morton, Daniel S.; Srinivasan, Venkat; Stefan, Peter M.

    2015-08-07

    To cover a large photon energy range, the length of an X-ray mirror is often longer than the beam footprint length for much of the applicable energy range. To limit thermal deformation of such a water-cooled X-ray mirror, a technique using side cooling with a cooled length shorter than the beam footprint length is proposed. This cooling length can be optimized by using finite-element analysis. For the Kirkpatrick–Baez (KB) mirrors at LCLS-II, the thermal deformation can be reduced by a factor of up to 30, compared with full-length cooling. Furthermore, a second, alternative technique, based on a similar principle is presented: using a long, single-length cooling block on each side of the mirror and adding electric heaters between the cooling blocks and the mirror substrate. The electric heaters consist of a number of cells, located along the mirror length. The total effective length of the electric heater can then be adjusted by choosing which cells to energize, using electric power supplies. The residual height error can be minimized to 0.02 nm RMS by using optimal heater parameters (length and power density). Compared with a case without heaters, this residual height error is reduced by a factor of up to 45. The residual height error in the LCLS-II KB mirrors, due to free-electron laser beam heat load, can be reduced by a factor of ~11belowthe requirement. The proposed techniques are also effective in reducing thermal slope errors and are, therefore, applicable to white beam mirrors in synchrotron radiation beamlines.

  15. Optimizing X-ray mirror thermal performance using matched profile cooling.

    PubMed

    Zhang, Lin; Cocco, Daniele; Kelez, Nicholas; Morton, Daniel S; Srinivasan, Venkat; Stefan, Peter M

    2015-09-01

    To cover a large photon energy range, the length of an X-ray mirror is often longer than the beam footprint length for much of the applicable energy range. To limit thermal deformation of such a water-cooled X-ray mirror, a technique using side cooling with a cooled length shorter than the beam footprint length is proposed. This cooling length can be optimized by using finite-element analysis. For the Kirkpatrick-Baez (KB) mirrors at LCLS-II, the thermal deformation can be reduced by a factor of up to 30, compared with full-length cooling. Furthermore, a second, alternative technique, based on a similar principle is presented: using a long, single-length cooling block on each side of the mirror and adding electric heaters between the cooling blocks and the mirror substrate. The electric heaters consist of a number of cells, located along the mirror length. The total effective length of the electric heater can then be adjusted by choosing which cells to energize, using electric power supplies. The residual height error can be minimized to 0.02 nm RMS by using optimal heater parameters (length and power density). Compared with a case without heaters, this residual height error is reduced by a factor of up to 45. The residual height error in the LCLS-II KB mirrors, due to free-electron laser beam heat load, can be reduced by a factor of ∼11 below the requirement. The proposed techniques are also effective in reducing thermal slope errors and are, therefore, applicable to white beam mirrors in synchrotron radiation beamlines.

  16. Performance of the Lead-Alloy Cooled Concept Balanced for Actinide Burning and Electricity Production

    SciTech Connect

    Pavel Hejzlar; Cliff Davis

    2004-09-01

    A lead-bismuth-cooled fast reactor concept targeted for a balanced mission of actinide burning and low-cost electricity production is proposed and its performance analyzed. The design explores the potential benefits of thorium-based fuel in actinide-burning cores, in particular in terms of the reduction of the large reactivity swing and enhancement of the small Doppler coefficient typical of fertile-free actinide burners. Reduced electricity production cost is pursued through a longer cycle length than that used for fertile-free burners and thus a higher capacity factor. It is shown that the concept can achieve a high transuranics destruction rate, which is only 20% lower than that of an accelerator-driven system with fertile-free fuel. The small negative fuel temperature reactivity coefficient, small positive coolant temperature reactivity coefficient, and negative core radial expansion coefficient provide self-regulating characteristics so that the reactor is capable of inherent shutdown during major transients without scram, as in the Integral Fast Reactor. This is confirmed by thermal-hydraulic analysis of several transients without scram, including primary coolant pump trip, station blackout, and reactivity step insertion, which showed that the reactor was able to meet all identified thermal limits. However, the benefits of high actinide consumption and small reactivity swing can be attained only if the uranium from the discharged fuel is separated and not recycled. This additional uranium separation step and thorium reprocessing significantly increase the fuel cycle costs. Because the higher fuel cycle cost has a larger impact on the overall cost of electricity than the savings from the higher capacity factor afforded through use of thorium, this concept appears less promising than the fertile-free actinide burners.

  17. Performance of the Lead-Alloy-Cooled Reactor Concept Balanced for Actinide Burning and Electricity Production

    SciTech Connect

    Hejzlar, Pavel; Davis, Cliff B.

    2004-09-15

    A lead-bismuth-cooled fast reactor concept targeted for a balanced mission of actinide burning and low-cost electricity production is proposed and its performance analyzed. The design explores the potential benefits of thorium-based fuel in actinide-burning cores, in particular in terms of the reduction of the large reactivity swing and enhancement of the small Doppler coefficient typical of fertile-free actinide burners. Reduced electricity production cost is pursued through a longer cycle length than that used for fertile-free burners and thus a higher capacity factor. It is shown that the concept can achieve a high transuranics destruction rate, which is only 20% lower than that of an accelerator-driven system with fertile-free fuel. The small negative fuel temperature reactivity coefficient, small positive coolant temperature reactivity coefficient, and negative core radial expansion coefficient provide self-regulating characteristics so that the reactor is capable of inherent shutdown during major transients without scram, as in the Integral Fast Reactor. This is confirmed by thermal-hydraulic analysis of several transients without scram, including primary coolant pump trip, station blackout, and reactivity step insertion, which showed that the reactor was able to meet all identified thermal limits. However, the benefits of high actinide consumption and small reactivity swing can be attained only if the uranium from the discharged fuel is separated and not recycled. This additional uranium separation step and thorium reprocessing significantly increase the fuel cycle costs. Because the higher fuel cycle cost has a larger impact on the overall cost of electricity than the savings from the higher capacity factor afforded through use of thorium, this concept appears less promising than the fertile-free actinide burners.

  18. Acoustic results of the Boeing model 360 whirl tower test

    NASA Technical Reports Server (NTRS)

    Watts, Michael E.; Jordan, David

    1990-01-01

    An evaluation is presented for whirl tower test results of the Model 360 helicopter's advanced, high-performance four-bladed composite rotor system intended to facilitate over-200-knot flight. During these performance measurements, acoustic data were acquired by seven microphones. A comparison of whirl-tower tests with theory indicate that theoretical prediction accuracies vary with both microphone position and the inclusion of ground reflection. Prediction errors varied from 0 to 40 percent of the measured signal-to-peak amplitude.

  19. Performance Comparison of Metallic, Actinide Burning Fuel in Lead-Bismuth and Sodium Cooled Fast Reactors

    SciTech Connect

    Weaver, Kevan Dean; Herring, James Stephen; Mac Donald, Philip Elsworth

    2001-04-01

    Various methods have been proposed to “incinerate” or “transmutate” the current inventory of trans-uranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non-fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years.

  20. Augmented Reality Tower Technology Assessment

    NASA Technical Reports Server (NTRS)

    Reisman, Ronald J.; Brown, David M.

    2009-01-01

    Augmented Reality technology may help improve Air Traffic Control Tower efficiency and safety during low-visibility conditions. This paper presents the assessments of five off-duty controllers who shadow-controlled' with an augmented reality prototype in their own facility. Initial studies indicated unanimous agreement that this technology is potentially beneficial, though the prototype used in the study was not adequate for operational use. Some controllers agreed that augmented reality technology improved situational awareness, had potential to benefit clearance, control, and coordination tasks and duties and could be very useful for acquiring aircraft and weather information, particularly aircraft location, heading, and identification. The strongest objections to the prototype used in this study were directed at aircraft registration errors, unacceptable optical transparency, insufficient display performance in sunlight, inadequate representation of the static environment and insufficient symbology.

  1. Towers of hybrid mesons

    SciTech Connect

    Semay, Claude; Buisseret, Fabien; Silvestre-Brac, Bernard

    2009-05-01

    A hybrid meson is a quark-antiquark pair in which, contrary to ordinary mesons, the gluon field is in an excited state. In the framework of constituent models, the interaction potential is assumed to be the energy of an excited string. An approximate, but accurate, analytical solution of the Schroedinger equation with such a potential is presented. When applied to hybrid charmonia and bottomonia, towers of states are predicted in which the masses are a linear function of a harmonic oscillator band number for the quark-antiquark pair. Such a formula could be a reliable guide for the experimental detection of heavy hybrid mesons.

  2. 2. Southern Light Tower and Northern Light Tower, view north, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Southern Light Tower and Northern Light Tower, view north, south sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  3. Improvements in cooling water system performance using a total systems management approach

    SciTech Connect

    Rampf, J.; Nlenaber, M.; Bruyn, H.J. de

    1998-12-31

    Several serious problems were encountered in three different cooling water systems during the commissioning of a new synthetic fuels complex in 1992. Fouling of heat exchangers with a silica sediment as well as cases of microbiological growth were found. These problems persisted and after the first year of operation serious corrosion damage, iron precipitation and microbiological fouling of carbon steel exchanger tubes were detected. At that point the need to change the cooling water management philosophy was realized and new tenders were invited for treatment of the systems The intent was to change from traditional reactive control to forward control using a high degree of automation. The emphasis was placed on buying a service which would provide agreed results for a fixed price based on cooling water system cycles of concentration. The paper reviews the dramatic improvements made since July 1994 in terms of corrosion control, fouling control, pH control, TDS/conductivity control and the control of microbiological species.

  4. Performance of conduction cooled splittable superconducting magnet package for linear accelerators

    DOE PAGES

    Kashikhin, Vladimire S.; Andreev, N.; Cheban, S.; DiMarco, J.; Kimura, N.; Makarov, A.; Orlov, Y.; V. Poloubotko; Tartaglia, M.; Yamamoto, A.

    2016-02-19

    New Linear Superconducting Accelerators need a superconducting magnet package installed inside SCRF Cryomodules to focus and steer electron or proton beams. A superconducting magnet package was designed and built as a collaborative effort of FNAL and KEK. The magnet package includes one quadrupole, and two dipole windings. It has a splittable in the vertical plane configuration, and features for conduction cooling. The magnet was successfully tested at room temperature, in a liquid He bath, and in a conduction cooling experiment. The paper describes the design and test results including: magnet cooling, training, and magnetic measurements by rotational coils. Furthermore, themore » effects of superconductor and iron yoke magnetization, hysteresis, and fringe fields are discussed.« less

  5. Design and performance of personal cooling garments based on three-layer laminates.

    PubMed

    Rothmaier, M; Weder, M; Meyer-Heim, A; Kesselring, J

    2008-08-01

    Personal cooling systems are mainly based on cold air or liquids circulating through a tubing system. They are weighty, bulky and depend on an external power source. In contrast, the laminate-based technology presented here offers new flexible and light weight cooling garments integrated into textiles. It is based on a three-layer composite assembled from two waterproof, but water vapor permeable membranes and a hydrophilic fabric in between. Water absorbed in the fabric will be evaporated by the body temperature resulting in cooling energy. The laminate's high adaptiveness makes it possible to produce cooling garments even for difficult anatomic topologies. The determined cooling energy of the laminate depends mainly on the environmental conditions (temperature, relative humidity, wind): heat flux at standard climatic conditions (20 degrees C, 65% R.H., wind 5 km/h) has measured 423.2 +/- 52.6 W/m(2), water vapor transmission resistance, R (et), 10.83 +/- 0.38 m(2) Pa/W and thermal resistance, R (ct), 0.010 +/- 0.002 m(2) K/W. Thermal conductivity, k, changed from 0.048 +/- 0.003 (dry) to 0.244 +/- 0.018 W/m K (water added). The maximum fall in skin temperature, Delta T (max), under the laminate was 5.7 +/- 1.2 degrees C, taken from a 12 subject study with a thigh cooling garment during treadmill walking (23 degrees C, 50% R.H., no wind) and a significant linear correlation (R = 0.85, P = 0.01) between body mass index and time to reach 67% of Delta T (max) could be determined.

  6. Method and apparatus for enhancing reactor air-cooling system performance

    DOEpatents

    Hunsbedt, Anstein

    1996-01-01

    An enhanced decay heat removal system for removing heat from the inert gas-filled gap space between the reactor vessel and the containment vessel of a liquid metal-cooled nuclear reactor. Multiple cooling ducts in flow communication with the inert gas-filled gap space are incorporated to provide multiple flow paths for the inert gas to circulate to heat exchangers which remove heat from the inert gas, thereby introducing natural convection flows in the inert gas. The inert gas in turn absorbs heat directly from the reactor vessel by natural convection heat transfer.

  7. Method and apparatus for enhancing reactor air-cooling system performance

    DOEpatents

    Hunsbedt, A.

    1996-03-12

    An enhanced decay heat removal system is disclosed for removing heat from the inert gas-filled gap space between the reactor vessel and the containment vessel of a liquid metal-cooled nuclear reactor. Multiple cooling ducts in flow communication with the inert gas-filled gap space are incorporated to provide multiple flow paths for the inert gas to circulate to heat exchangers which remove heat from the inert gas, thereby introducing natural convection flows in the inert gas. The inert gas in turn absorbs heat directly from the reactor vessel by natural convection heat transfer. 6 figs.

  8. Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion

    SciTech Connect

    Cornejo, J. M.; Colombano, M.; Doménech, J.; Rodríguez, D.; Block, M.; Delahaye, P.

    2015-10-15

    A special ion trap was initially built up to perform β-ν correlation experiments with radioactive ions. The trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single {sup 40}Ca{sup +} ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on {sup 40}Ca{sup +} ions, starting from large clouds and reaching single ion sensitivity. This new feature of the trap might be important also for other experiments with ions produced at radioactive ion beam facilities. In this publication, the trap and the laser system will be described, together with their performance with respect to laser cooling applied to large ion clouds down to a single ion.

  9. Experimental study on corrugated cross-flow air-cooled plate heat exchangers

    SciTech Connect

    Kim, Minsung; Baik, Young-Jin; Park, Seong-Ryong; Ra, Ho-Sang; Lim, Hyug

    2010-11-15

    Experimental study on cross-flow air-cooled plate heat exchangers (PHEs) was performed. The two prototype PHEs were manufactured in a stack of single-wave plates and double-wave plates in parallel. Cooling air flows through the PHEs in a crosswise direction against internal cooling water. The heat exchanger aims to substitute open-loop cooling towers with closed-loop water circulation, which guarantees cleanliness and compactness. In this study, the prototype PHEs were tested in a laboratory scale experiments. From the tests, double-wave PHE shows approximately 50% enhanced heat transfer performance compared to single-wave PHE. However, double-wave PHE costs 30% additional pressure drop. For commercialization, a wide channel design for air flow would be essential for reliable performance. (author)

  10. FLORIDA TOWER FOOTPRINT EXPERIMENTS

    SciTech Connect

    WATSON,T.B.; DIETZ, R.N.; WILKE, R.; HENDREY, G.; LEWIN, K.; NAGY, J.; LECLERC, M.

    2007-01-01

    The Florida Footprint experiments were a series of field programs in which perfluorocarbon tracers were released in different configurations centered on a flux tower to generate a data set that can be used to test transport and dispersion models. These models are used to determine the sources of the CO{sub 2} that cause the fluxes measured at eddy covariance towers. Experiments were conducted in a managed slash pine forest, 10 km northeast of Gainesville, Florida, in 2002, 2004, and 2006 and in atmospheric conditions that ranged from well mixed, to very stable, including the transition period between convective conditions at midday to stable conditions after sun set. There were a total of 15 experiments. The characteristics of the PFTs, details of sampling and analysis methods, quality control measures, and analytical statistics including confidence limits are presented. Details of the field programs including tracer release rates, tracer source configurations, and configuration of the samplers are discussed. The result of this experiment is a high quality, well documented tracer and meteorological data set that can be used to improve and validate canopy dispersion models.

  11. The Cooling and Lubrication Performance of Graphene Platelets in Micro-Machining Environments

    NASA Astrophysics Data System (ADS)

    Chu, Bryan

    The research presented in this thesis is aimed at investigating the use of graphene platelets (GPL) to address the challenges of excessive tool wear, reduced part quality, and high specific power consumption encountered in micro-machining processes. There are two viable methods of introducing GPL into micro-machining environments, viz., the embedded delivery method, where the platelets are embedded into the part being machined, and the external delivery method, where graphene is carried into the cutting zone by jetting or atomizing a carrier fluid. The study involving the embedded delivery method is focused on the micro-machining performance of hierarchical graphene composites. The results of this study show that the presence of graphene in the epoxy matrix improves the machinability of the composite. In general, the tool wear, cutting forces, surface roughness, and extent of delamination are all seen to be lower for the hierarchical composite when compared to the conventional two-phase glass fiber composite. These improvements are attributed to the fact that graphene platelets improve the thermal conductivity of the matrix, provide lubrication at the tool-chip interface and also improve the interface strength between the glass fibers and the matrix. The benefits of graphene are seen to also carry over to the external delivery method. The platelets provide improved cooling and lubrication performance to both environmentally-benign cutting fluids as well as to semi-synthetic cutting fluids used in micro-machining. The cutting performance is seen to be a function of the geometry (i.e., lateral size and thickness) and extent of oxygen-functionalization of the platelet. Ultrasonically exfoliated platelets (with 2--3 graphene layers and lowest in-solution characteristic lateral length of 120 nm) appear to be the most favorable for micro-machining applications. Even at the lowest concentration of 0.1 wt%, they are capable of providing a 51% reduction in the cutting

  12. Optomechanical performance of 3D-printed mirrors with embedded cooling channels and substructures

    NASA Astrophysics Data System (ADS)

    Mici, Joni; Rothenberg, Bradley; Brisson, Erik; Wicks, Sunny; Stubbs, David M.

    2015-09-01

    Advances in 3D printing technology allow for the manufacture of topologically complex parts not otherwise feasible through conventional manufacturing methods. Maturing metal and ceramic 3D printing technologies are becoming more adept at printing complex shapes, enabling topologically intricate mirror substrates. One application area that can benefit from additive manufacturing is reflective optics used in high energy laser (HEL) systems that require materials with a low coefficient of thermal expansion (CTE), high specific stiffness, and (most importantly) high thermal conductivity to effectively dissipate heat from the optical surface. Currently, the limits of conventional manufacturing dictate the topology of HEL optics to be monolithic structures that rely on passive cooling mechanisms and high reflectivity coatings to withstand laser damage. 3D printing enables the manufacture of embedded cooling channels in metallic mirror substrates to allow for (1) active cooling and (2) tunable structures. This paper describes the engineering and analysis of an actively cooled composite optical structure to demonstrate the potential of 3D printing on the improvement of optomechanical systems.

  13. Improved Performance of an Air Cooled Condenser (ACC) Using SPX Wind Guide Technology at Coal-Based Thermoelectric Power Plants

    SciTech Connect

    Ken Mortensen

    2010-12-31

    This project added a new airflow enhancement technology to an existing ACC cooling process at a selected coal power plant. Airflow parameters and efficiency improvement for the main plant cooling process using the applied technology were determined and compared with the capabilities of existing systems. The project required significant planning and pre-test execution in order to reach the required Air Cooled Condenser system configuration for evaluation. A host Power Plant ACC system had to be identified, agreement finalized, and addition of the SPX ACC Wind Guide Technology completed on that site. Design of the modification, along with procurement, fabrication, instrumentation, and installation of the new airflow enhancement technology were executed. Baseline and post-modification cooling system data was collected and evaluated. The improvement of ACC thermal performance after SPX wind guide installation was clear. Testing of the improvement indicates there is a 5% improvement in heat transfer coefficient in high wind conditions and 1% improvement at low wind speed. The benefit increased with increasing wind speed. This project was completed on schedule and within budget.

  14. Comparison of active cooling devices to passive cooling for rehabilitation of firefighters performing exercise in thermal protective clothing: A report from the Fireground Rehab Evaluation (FIRE) trial

    PubMed Central

    Hostler, David; Reis, Steven E; Bednez, James C; Kerin, Sarah; Suyama, Joe

    2010-01-01

    Background Thermal protective clothing (TPC) worn by firefighters provides considerable protection from the external environment during structural fire suppression. However, TPC is associated with physiological derangements that may have adverse cardiovascular consequences. These derangements should be treated during on-scene rehabilitation periods. Objective The present study examined heart rate and core temperature responses during the application of four active cooling devices, currently being marketed to the fire service for on-scene rehab, and compared them to passive cooling in a moderate temperature (approximately 24°C) and to an infusion of cold (4°C) saline. Methods Subjects exercised in TPC in a heated room. Following an initial exercise period (BOUT 1) the subjects exited the room, removed TPC, and for 20 minutes cooled passively at room temperature, received an infusion of cold normal saline, or were cooled by one of four devices (fan, forearm immersion in water, hand cooling, water perfused cooling vest). After cooling, subjects donned TPC and entered the heated room for another 50-minute exercise period (BOUT 2). Results Subjects were not able to fully recover core temperature during a 20-minute rehab period when provided rehydration and the opportunity to completely remove TPC. Exercise duration was shorter during BOUT 2 when compared to BOUT 1 but did not differ by cooling intervention. The overall magnitude and rate of cooling and heart rate recovery did not differ by intervention. Conclusions No clear advantage was identified when active cooling devices and cold intravenous saline were compared to passive cooling in a moderate temperature after treadmill exercise in TPC. PMID:20397868

  15. Numerical investigation of thermal performance of a water-cooled mini-channel heat sink for different chip arrangement

    NASA Astrophysics Data System (ADS)

    Tikadar, Amitav; Hossain, Md. Mahamudul; Morshed, A. K. M. M.

    2016-07-01

    Heat transfer from electronic chip is always challenging and very crucial for electronic industry. Electronic chips are assembled in various manners according to the design conditions and limitationsand thus the influence of chip assembly on the overall thermal performance needs to be understand for the efficient design of electronic cooling system. Due to shrinkage of the dimension of channel and continuous increment of thermal load, conventional heat extraction techniques sometimes become inadequate. Due to high surface area to volume ratio, mini-channel have the natural advantage to enhance convective heat transfer and thus to play a vital role in the advanced heat transfer devices with limited surface area and high heat flux. In this paper, a water cooled mini-channel heat sink was considered for electronic chip cooling and five different chip arrangements were designed and studied, namely: the diagonal arrangement, parallel arrangement, stacked arrangement, longitudinal arrangement and sandwiched arrangement. Temperature distribution on the chip surfaces was presented and the thermal performance of the heat sink in terms of overall thermal resistance was also compared. It is found that the sandwiched arrangement of chip provides better thermal performance compared to conventional in line chip arrangement.

  16. Vibration analysis of three guyed tower designs for intermediate size wind turbines

    NASA Technical Reports Server (NTRS)

    Christie, R. J.

    1982-01-01

    Three guyed tower designs were analyzed for intermediate size wind turbines. The four lowest natural frequencies of vibration of the three towers concepts were estimated. A parametric study was performed on each tower to determine the effect of varying such tower properties as the inertia and stiffness of the tower and guys, the inertia values of the nacelle and rotor, and the rotational speed of the rotor. Only the two lowest frequencies were in a range where they could be excited by the rotor blade passing frequencies. There two frequencies could be tuned by varying the guy stiffness, the guy attachment point on the tower, the tower and mass stiffness, and the nacelle/rotor/power train masses.

  17. Correlation of the Characteristics of Single-Cylinder and Flight Engines in Tests of High-Performance Fuels in an Air-Cooled Engine I : Cooling Characteristics

    NASA Technical Reports Server (NTRS)

    Wilson, Robert W.; Richard, Paul H.; Brown, Kenneth D.

    1945-01-01

    Variable charge-air flow, cooling-air pressure drop, and fuel-air ration investigations were conducted to determine the cooling characteristics of a full-scale air-cooled single cylinder on a CUE setup. The data are compared with similar data that were available for the same model multicylinder engine tested in flight in a four-engine airplane. The cylinder-head cooling correlations were the same for both the single-cylinder and the flight engine. The cooling correlations for the barrels differed slightly in that the barrel of the single-cylinder engine runs cooler than the barrel of te flight engine for the same head temperatures and engine conditions.

  18. Design, construction and cooling system performance of a prototype cryogenic stopping cell for the Super-FRS at FAIR

    NASA Astrophysics Data System (ADS)

    Ranjan, M.; Dendooven, P.; Purushothaman, S.; Dickel, T.; Reiter, M. P.; Ayet, S.; Haettner, E.; Moore, I. D.; Kalantar-Nayestanaki, N.; Geissel, H.; Plaß, W. R.; Schäfer, D.; Scheidenberger, C.; Schreuder, F.; Timersma, H.; Van de Walle, J.; Weick, H.

    2015-01-01

    A cryogenic stopping cell for stopping energetic radioactive ions and extracting them as a low energy beam was developed. This first ever cryogenically operated stopping cell serves as prototype device for the Low-Energy Branch of the Super-FRS at FAIR. The cell has a stopping volume that is 1 m long and 25 cm in diameter. Ions are guided by a DC field along the length of the stopping cell and by a combined RF and DC fields provided by an RF carpet at the exit-hole side. The ultra-high purity of the stopping gas required for optimum ion survival is reached by cryogenic operation. The design considerations and construction of the cryogenic stopping cell, as well as some performance characteristics, are described in detail. Special attention is given to the cryogenic aspects in the design and construction of the stopping cell and the cryocooler-based cooling system. The cooling system allows the operation of the stopping cell at any desired temperature between about 70 K and room temperature. The cooling system performance in realistic on-line conditions at the FRS Ion Catcher Facility at GSI is discussed. A temperature of 110 K at which efficient ion survival was observed is obtained after 10 h of cooling. A minimum temperature of the stopping gas of 72 K was reached. The expertise gained from the design, construction and performance of the prototype cryogenic stopping cell has allowed the development of a final version for the Low-Energy Branch of the Super-FRS to proceed.

  19. Experimental and numerical analysis of the cooling performance of water spraying systems during a fire.

    PubMed

    Chen, YaoHan; Su, ChungHwei; Tseng, JoMing; Li, WunJie

    2015-01-01

    The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS) overestimated the space temperature before water spraying in the case of the same water spray system.

  20. Experimental and numerical analysis of the cooling performance of water spraying systems during a fire.

    PubMed

    Chen, YaoHan; Su, ChungHwei; Tseng, JoMing; Li, WunJie

    2015-01-01

    The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS) overestimated the space temperature before water spraying in the case of the same water spray system. PMID:25723519

  1. Radiation protection performance for the dismantling of the WWR-M primary cooling circuit.

    PubMed

    Lobach, Yu N; Luferenko, E D; Shevel, V N

    2014-12-01

    The WWR-M is a light-water-cooled and moderated heterogonous research reactor with a thermal output of 10 MW. The reactor has been in operation for >50 y and has had an excellent safety record. A non-hermeticity of the inlet line of the primary cooling circuit (PCC) was found, and the only reasonable technical solution was the complete replacement of the PCC inlet and outlet pipe lines. Such a replacement was a challenging technical task due to the necessity to handle large size components with complex geometries under conditions of high-level radiation fields, and therefore, it required detailed planning aiming to reduce staff exposure. This paper describes the dismantling and removal of the PCC components focusing on radiation protection issues.

  2. Experimental and Numerical Analysis of the Cooling Performance of Water Spraying Systems during a Fire

    PubMed Central

    Chen, YaoHan; Su, ChungHwei; Tseng, JoMing; Li, WunJie

    2015-01-01

    The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS) overestimated the space temperature before water spraying in the case of the same water spray system. PMID:25723519

  3. Meta-analysis of the effects of microclimate cooling systems on human performance under thermal stressful environments: potential applications to occupational workers.

    PubMed

    Chan, Albert P C; Song, Wenfang; Yang, Yang

    2015-01-01

    This study aims to determine the appropriate microclimate cooling systems (MCSs) to reduce heat stress and improve human performance of occupational workers and their practicality in the occupational field. Meta-analysis was employed to summarize, analyze, and compare the effects of various MCSs on human performance with corresponding physiological and psychological responses, thereby providing solid suggestions for selecting suitable MCSs for occupational workers. Wearing MCSs significantly attenuated the increases in core temperature (-0.34 °C/h) and sweating rate (-0.30 L/h), and significantly improved human performance (+29.9%, effect size [EFS] = 1.1) compared with no cooling condition (CON). Cold air-cooled garments (ACG-Cs; +106.2%, EFS = 2.32) exhibited greater effects on improving human performance among various microclimate cooling garments (MCGs), followed by liquid cooling garments (LCGs; +68.1%, EFS = 1.86) and hybrid cooling garment combining air and liquid cooling (HBCG-AL; +59.1%, EFS=3.38), natural air-cooled garments (ACG-Ns; +39.9%, EFS = 1.12), and phase change material cooling garments (PCMCGs; +19.5%, EFS = 1.2). Performance improvement was observed to be positively and linearly correlated to the differences of core temperature increase rate (r = 0.65, p < 0.01) and sweating rate (r = 0.80, p < 0.001) between MCSs and CON. Considering their application in industrial settings, ACG-Cs, LCGs, and HBCG-AL are practical for work, in which workers do not move frequently, whereas ACG-Ns and PCMCGs are more applicable for the majority of occupational workers. Further enhancement of the cooling efficiency of these two cooling strategies should be initiated.

  4. Meta-analysis of the effects of microclimate cooling systems on human performance under thermal stressful environments: potential applications to occupational workers.

    PubMed

    Chan, Albert P C; Song, Wenfang; Yang, Yang

    2015-01-01

    This study aims to determine the appropriate microclimate cooling systems (MCSs) to reduce heat stress and improve human performance of occupational workers and their practicality in the occupational field. Meta-analysis was employed to summarize, analyze, and compare the effects of various MCSs on human performance with corresponding physiological and psychological responses, thereby providing solid suggestions for selecting suitable MCSs for occupational workers. Wearing MCSs significantly attenuated the increases in core temperature (-0.34 °C/h) and sweating rate (-0.30 L/h), and significantly improved human performance (+29.9%, effect size [EFS] = 1.1) compared with no cooling condition (CON). Cold air-cooled garments (ACG-Cs; +106.2%, EFS = 2.32) exhibited greater effects on improving human performance among various microclimate cooling garments (MCGs), followed by liquid cooling garments (LCGs; +68.1%, EFS = 1.86) and hybrid cooling garment combining air and liquid cooling (HBCG-AL; +59.1%, EFS=3.38), natural air-cooled garments (ACG-Ns; +39.9%, EFS = 1.12), and phase change material cooling garments (PCMCGs; +19.5%, EFS = 1.2). Performance improvement was observed to be positively and linearly correlated to the differences of core temperature increase rate (r = 0.65, p < 0.01) and sweating rate (r = 0.80, p < 0.001) between MCSs and CON. Considering their application in industrial settings, ACG-Cs, LCGs, and HBCG-AL are practical for work, in which workers do not move frequently, whereas ACG-Ns and PCMCGs are more applicable for the majority of occupational workers. Further enhancement of the cooling efficiency of these two cooling strategies should be initiated. PMID:25774023

  5. Performance of thermal shields of LHD cryostat cooled by gaseous helium with parallel paths

    NASA Astrophysics Data System (ADS)

    Imagawa, S.; Tamura, H.; Yanagi, N.; Sekiguchi, H.; Mito, T.; Satow, T.

    2002-05-01

    The Large Helical Device is the largest cryogenic apparatus for a research of fusion plasma. Thermal shields are installed to reduce heat loads to the superconducting coils. Since the total area is very wide, seamless pipes were adopted to reduce the possibility of helium leakage, and parallel cooling path is indispensable to reduce the pressure drop. Temperature differences between parallel paths will be enlarged with the procedure of cool-down, but the final temperature should be determined uniquely by each heat load in the case of gaseous helium. The number of parallel paths of the thermal shields for the plasma vacuum vessel and the cryostat vessel are set to 20 and 10, respectively, to form the periodic symmetry. The pipes were attached on the segmented plates of SUS316 by metal cleats mechanically and by high conductive epoxy resin thermally. The maximum temperature difference between the outlets of the paths was enlarged with the procedure of cool-down, but it was saturated within 40% of the average temperature rise. This difference is allowable in this system, and the temperature differences are coincide the difference of area due to the irregular shape.

  6. Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow

    PubMed Central

    2011-01-01

    This study analyzes the characteristics of alumina (Al2O3)/water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3/water nanofluid produced by the direct synthesis method at three different concentrations (0.5, 1.0, and 1.5 wt.%). The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample temperatures (20-60°C), and then used the nanofluid in an actual air-cooled heat exchanger to assess its heat exchange capacity and pressure drop under laminar flow. Experimental results show that the nanofluid has a higher heat exchange capacity than water, and a higher concentration of nanoparticles provides an even better ratio of the heat exchange. The maximum enhanced ratio of heat exchange and pressure drop for all the experimental parameters in this study was about 39% and 5.6%, respectively. In addition to nanoparticle concentration, the temperature and mass flow rates of the working fluid can affect the enhanced ratio of heat exchange and pressure drop of nanofluid. The cross-section aspect ratio of tube in the heat exchanger is another important factor to be taken into consideration. PMID:21827644

  7. Effect of porosity and the inlet heat transfer fluid temperature variation on the performance of cool thermal energy storage system

    NASA Astrophysics Data System (ADS)

    Cheralathan, M.; Velraj, R.; Renganarayanan, S.

    2007-06-01

    This paper discusses the results of numerical and experimental study of an encapsulated cool thermal energy storage system. The storage system is a cylindrical storage tank filled with phase change material encapsulated in spherical container, placed in a refrigeration loop. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid and the phase change material at any axial location during the charging period. The present analysis aims at studying the influence of the inlet heat transfer fluid temperature and porosity on system performance. An experimental setup was designed and constructed to conduct the experiments. The results of the model were validated by comparison with experimental results of temperature profiles for different inlet heat transfer fluid temperatures and porosity. The results are in good agreement with the experimental results. The results reported are much useful for designing cool thermal energy storage systems.

  8. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

  9. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

    NASA Astrophysics Data System (ADS)

    1981-03-01

    The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

  10. Solar heating and cooling with the CaCl2-CH3OH chemical heat pump

    NASA Astrophysics Data System (ADS)

    Offenhartz, P. O.

    1982-03-01

    A chemical heat pump based on the reaction of calcium chloride and methanol is being designed and optimized for solar heating and air conditioning, primarily for the residential and light commercial market. The performance requirements for this application are quite stringent. For example, to minimize maintenance, a cooling tower should not be used, and the solar collectors should be fixed rooftop flat plates or evacuated tubes. The chiller should be capable of reaching 45 F on a 95 F day in order to provide effective dehumidification. Energy storage for late afternoon and early evening cooling, as well as night time winter heating, must be provided.

  11. The effect of passive heating and head cooling on perception, cardiovascular function and cognitive performance in the heat.

    PubMed

    Simmons, Shona E; Saxby, Brian K; McGlone, Francis P; Jones, David A

    2008-09-01

    The present study examined the effects of raising both skin temperature and core temperature, separately and in combination, on perceptions of heat-related fatigue (alertness, contentment, calmness and thermal comfort), cardiovascular function and on objective measures of cognitive performance (reaction time and accuracy). Ten (six males) subjects had cognitive performance assessed in three conditions; at low skin and low core temperature (LL), at high skin and low core temperature (HL) and at high skin and high core temperatures (HH). In one trial, subjects had their head and neck cooled (HC); the other trial was a control (CON). Raising skin temperature increased heart rate and decreased perception of thermal comfort (P < 0.05), whereas raising both skin and core temperature decreased perception of heat-related fatigue (P < 0.05) and increased cardiovascular strain (P < 0.05) resulting in decrements in cognitive performance shown by faster reaction times (P < 0.05) and a loss of accuracy (P < 0.05). At high skin and core temperatures, cooling the head and neck improved feelings of heat-related fatigue (P < 0.05) and cardiovascular strain (P < 0.05), but had no effect on cognitive performance. In conclusion, the results of this study suggest that feelings of heat-related fatigue and cardiovascular strain can be attributed to a combination of elevated skin and core body temperature, whereas decrements in cognitive performance can be attributed to an elevated core temperature.

  12. You're a What?: Tower Technician

    ERIC Educational Resources Information Center

    Vilorio, Dennis

    2012-01-01

    In this article, the author talks about the role and functions of a tower technician. A tower technician climbs up the face of telecommunications towers to remove, install, test, maintain, and repair a variety of equipment--from antennas to light bulbs. Tower technicians also build shelters and radiofrequency shields for electronic equipment, lay…

  13. 11. SITE BUILDING 002 SCANNER BUILDING EVAPORATIVE COOLING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. SITE BUILDING 002 - SCANNER BUILDING - EVAPORATIVE COOLING TOWER SYSTEM IN FOREGROUND. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

  14. Dynamic analysis of the Milad Tower

    NASA Astrophysics Data System (ADS)

    Wilhelm, Edwin; Ford, Mitchell; Coelho, Darren; Lawler, Lachlan; Ansourian, Peter; Alonso-Marroquin, Fernando; Tahmasebinia, Faham

    2016-08-01

    This report involves the modelling of the Milad Tower using the finite element analysis program Strand7. A dynamic analysis was performed on the structure in order to understand the deflections and stresses as a result of earthquake and wind loading. In particular, Linear Static as well as Natural Frequency and Spectral Response solvers were used to determine the behaviour of the structure under loading. The findings of the report highlight that the structure was modelled accurately with the outputs representing realistic values. The report suggests that the design of the beams, columns, slabs and all structural members was sufficient enough to support the tower during maximum loading cases. The governing load case was earthquake loading.

  15. Performance of semi-transportation-cooled liner in high-temperature-rise combustors

    NASA Technical Reports Server (NTRS)

    Wear, J. D.; Trout, A. M.; Smith, J. M.

    1981-01-01

    Results from tests with the Lamilloy combustor liner are compared with results obtained from a conventionally designed, film cooled, step-louver liner. Operation of the Lamilloy liner with counterrotating swirl combustor fuel modules with mixing venturis was possible to a fuel-air ratio of 0.065 without obtaining excessive liner metal temperatures. At the 0.065 fuel-air condition the average liner metal temperature was 140 K and the maximum local temperature 280 K above the inlet air temperature. Combustion efficiency, pattern factor, and smoke data are discussed.

  16. Improving photovoltaic performance through radiative cooling in both terrestrial and extraterrestrial environments.

    PubMed

    Safi, Taqiyyah S; Munday, Jeremy N

    2015-09-21

    The method of detailed balance, introduced by Shockley and Queisser, is often used to find an upper theoretical limit for the efficiency of semiconductor pn-junction based photovoltaics. Typically the solar cell is assumed to be at an ambient temperature of 300 K. In this paper, we describe and analyze the use of radiative cooling techniques to lower the solar cell temperature below the ambient to surpass the detailed balance limit for a cell in contact with an ideal heat sink. We show that by combining specifically designed radiative cooling structures with solar cells, efficiencies higher than the limiting efficiency achievable at 300 K can be obtained for solar cells in both terrestrial and extraterrestrial environments. We show that our proposed structure yields an efficiency 0.87% higher than a typical PV module at operating temperatures in a terrestrial application. We also demonstrate an efficiency advantage of 0.4-2.6% for solar cells in an extraterrestrial environment in near-earth orbit.

  17. Improving photovoltaic performance through radiative cooling in both terrestrial and extraterrestrial environments.

    PubMed

    Safi, Taqiyyah S; Munday, Jeremy N

    2015-09-21

    The method of detailed balance, introduced by Shockley and Queisser, is often used to find an upper theoretical limit for the efficiency of semiconductor pn-junction based photovoltaics. Typically the solar cell is assumed to be at an ambient temperature of 300 K. In this paper, we describe and analyze the use of radiative cooling techniques to lower the solar cell temperature below the ambient to surpass the detailed balance limit for a cell in contact with an ideal heat sink. We show that by combining specifically designed radiative cooling structures with solar cells, efficiencies higher than the limiting efficiency achievable at 300 K can be obtained for solar cells in both terrestrial and extraterrestrial environments. We show that our proposed structure yields an efficiency 0.87% higher than a typical PV module at operating temperatures in a terrestrial application. We also demonstrate an efficiency advantage of 0.4-2.6% for solar cells in an extraterrestrial environment in near-earth orbit. PMID:26406742

  18. Carbohydrate ingestion and pre-cooling improves exercise capacity following soccer-specific intermittent exercise performed in the heat.

    PubMed

    Clarke, N D; Maclaren, D P M; Reilly, T; Drust, B

    2011-07-01

    Ingestion of carbohydrate and reducing core body temperature pre-exercise, either separately or combined, may have ergogenic effects during prolonged intermittent exercise in hot conditions. The aim of this investigation was to examine the effect of carbohydrate ingestion and pre-cooling on the physiological responses to soccer-specific intermittent exercise and the impact on subsequent high-intensity exercise performance in the heat. Twelve male soccer players performed a soccer-specific intermittent protocol for 90 min in the heat (30.5°C and 42.2% r.h.) on four occasions. On two occasions, the participants underwent a pre-cooling manoeuvre. During these sessions either a carbohydrate-electrolyte solution (CHOc) or a placebo was consumed at (PLAc). During the remaining sessions either the carbohydrate-electrolyte solution (CHO) or placebo (PLA) was consumed. At 15-min intervals throughout the protocol participants performed a mental concentration test. Following the soccer-specific protocol participants performed a self-chosen pace test and a test of high-intensity exercise capacity. The period of pre-cooling significantly reduced core temperature, muscle temperature and thermal sensation (P < 0.05). Self-chosen pace was greater with CHOc (12.5 ± 0.5 km h(-1)) compared with CHO (11.3 ± 0.4 km h(-1)), PLA (11.3 ± 0.4 km h(-1)) and PLAc (11.6 ± 0.5 km h(-1)) (P < 0.05). High-intensity exercise capacity was improved with CHOc and CHO when compared with PLA (CHOc; 79.8 ± 7 s, CHO; 72.1 ± 5 s, PLAc; 70.1 ± 8 s, PLA; 57.1 ± 5 s; P < 0.05). Mental concentration during the protocol was also enhanced during CHOc compared with PLA (P < 0.05). These results suggest pre-cooling in conjunction with the ingestion of carbohydrate during exercise enhances exercise capacity and helps maintain mental performance during intermittent exercise in hot conditions.

  19. Simulated performance of CIEE's 'Alternatives to Compressive Cooling' prototype house under design conditions in various California climates

    SciTech Connect

    Huang, Yu Joe

    1999-12-01

    To support the design development of a compressorless house that does not rely on mechanical air-conditioning, the author carried out detailed computer analysis of a prototypical house design to determine the indoor thermal conditions during peak cooling periods for over 170 California locations. The peak cooling periods are five-day sequences at 2{percent} frequency determined through statistical analysis of long-term historical weather data. The DOE-2 program was used to simulate the indoor temperatures of the house under four operating options: windows closed, with mechanical ventilation, evaporatively-cooled mechanical ventilation, or a conventional 1 1/2-ton air conditioner. The study found that with a 1500 CFM mechanical ventilation system, the house design would maintain comfort under peak conditions in the San Francisco Bay Area out to Walnut Creek, but not beyond. In southern California, the same system and house design would maintain adequate comfort only along the coast. With the evaporatively-cooled ventilation system, the applicability of the house design can be extended to Fairfield and Livermore in northern California, but in southern California a larger 3000 CFM system would be needed to maintain comfort conditions over half of the greater Los Angeles area, the southern half of the Inland Empire, and most of San Diego county. With the 1 1/2-ton air conditioner, the proposed house design would perform satisfactorily through most of the state, except in the upper areas of the Central Valley and the hot desert areas in southern California. In terms of energy savings, the simulations showed that the prototypical house design would save from 0.20 to 0.43 in northern California, 0.20 to 0.53 in southern California, and 0.16 to 0.35 in the Central Valley, the energy used by the same house design built to Title-24 requirements.

  20. Tower Temperature and Humidity Sensors (TWR) Handbook

    SciTech Connect

    Cook, DR

    2010-02-01

    Three tall towers are installed at the Atmospheric Radiation Measurement (ARM) Climate Research Facility: a 60-meter triangular tower at the Southern Great Plains (SGP) Central Facility (CF), a 21-meter walkup scaffolding tower at the SGP Okmulgee forest site (E21), and a 40-meter triangular tower at the North Slope of Alaska (NSA) Barrow site. The towers are used for meteorological, radiological, and other measurements.