Design and measured performance of a porous evaporative cooler for preservation of fruits and vegetables

International Nuclear Information System (INIS)

Anyanwu, E.E.

2004-01-01

The design, construction and measured performance of a porous evaporative cooler for preservation of fruits and vegetables are reported. The experimental cooler, with a total storage space of 0.014 m 3 , consists of a cuboid shaped porous clay container located inside another clay container. The gap between them is filled with coconut fibre. A water reservoir linked to the cooler at the top through a flexible pipe supplied water to fill the gap, thus keeping the coconut fibre continuously wet. Results of the transient performance tests revealed that the cooler storage chamber temperature depression from ambient air temperature varied over 0.1-12 deg. C. Ambient air temperatures during the test periods ranged over 22-38 deg. C. The results also illustrate superior performance of the cooler over open air preservation of vegetables soon after harvest during the diurnal operations. Thus, the evaporative cooler has prospects for use for short term preservation of vegetables and fruits soon after harvest

Hybrid coolers allow important water saving; Les refroidisseurs ''hybrides'' permettent des economies d'eau importantes

Energy Technology Data Exchange (ETDEWEB)

Bitsch, V. [Societe Jaeggi-France (France)

2005-03-01

Air cooling systems used with refrigerating machineries are in general highly water and electricity consuming. The use of 'hybrid' systems having the characteristics of both close-cycle evaporative systems and dry coolers allow important water saving. This article presents the operation principle and characteristics of such cooling systems. (J.S.)

Feasibility and impact of placing water coolers on sales of sugar-sweetened beverages in Dutch secondary school canteens

NARCIS (Netherlands)

Visscher, Tommy L S; van Hal, Wendy C W; Blokdijk, Lobke; Seidell, Jaap C; Renders, Carry M; Bemelmans, Wanda J E

2010-01-01

AIMS: The aim of this pilot study was to investigate the feasibility and effectiveness of placing water coolers on sugar-sweetened beverage sales at secondary schools (age 12-18 years) in the city of Zwolle, the Netherlands. METHODS: Six schools, hosting 5,866 pupils, were divided in three

Direct Evaporatrive Coolers of Gases and Liquids with Lowered Limit of Cooling

Directory of Open Access Journals (Sweden)

Doroshenko A.V.

2015-12-01

Full Text Available We have developed main technical solutions solution of indirect evaporative water and air coolers with reduced cooling limit. Packed part of heat-mass transfer devices is made of the film type based monoblock compositions of polymer materials. A mathematical model describing the processes of joint heat and mass transfer in evaporative coolers is executed. A comparative analysis of the possibilities of coolers designed based on experimental data on the efficiency of processes of heat and mass transfer.

The Recycler Electron Cooler

Energy Technology Data Exchange (ETDEWEB)

Shemyakin, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Prost, L. R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

2013-03-19

The Recycler Electron cooler was the first (and so far, the only) cooler working at a relativistic energy (γ = 9.5). It was successfully developed in 1995-2004 and was in operation at Fermilab in 2005-2011, providing cooling of antiprotons in the Recycler ring. This paper describes the cooler, difficulties in achieving the required electron beam parameters and the ways to overcome them, cooling measurements, and details of operation.

Sodium flow distribution test of the air cooler tubes

International Nuclear Information System (INIS)

Uchida, Hiroyuki; Ohta, Hidehisa; Shimazu, Hisashi

1980-01-01

In the heat transfer tubes of the air cooler which is installed in the auxiliary core cooling system of the fast breeder prototype plant reactor ''Monju'', sodium freezing may be caused by undercooling the sodium induced by an extremely unbalanced sodium flow in the tubes. Thus, the sodium flow distribution test of the air cooler tubes was performed to examine the flow distribution of the tubes and to estimate the possibility of sodium freezing in the tubes. This test was performed by using a one fourth air cooler model installed in the water flow test facility. As the test results show, the flow distribution from the inlet header to each tube is almost equal at any operating condition, that is, the velocity deviation from normalized mean velocity is less than 6% and sodium freezing does not occur up to 250% air velocity deviation at stand-by condition. It was clear that the proposed air cooler design for the ''Monju'' will have a good sodium flow distribution at any operating condition. (author)

Impulse sales cooler. Final report

Energy Technology Data Exchange (ETDEWEB)

Pedersen, Per Henrik (DTI, Taastrup (Denmark))

2010-11-15

In the past years, the use of impulse coolers has increased considerably and it is estimated that at least 30.000 are installed in shops in Denmark. In addition, there are many small barrel-shaped can coolers. Most impulse coolers are open, which results in a large consumption of energy, and the refrigeration systems are often quite inefficient. A typical impulse cooler uses app. 5 - 8 kWh/day corresponding to a consumption of energy in the magnitude of 60 GWh/year. For several years, the Danish company Vestfrost A/S has produced an impulse sales cooler in the high-efficiency end and the energy consumption of the cooler is measured to be 4.15 kWh/day. The POS72 cooler formed the baseline of this project. At the start-up meeting in 2008, several ideas were discussed with the objective to reduce energy consumption and to use natural refrigerants. Among the ideas were better air curtains, removable lids, better condensers, use of R600a refrigeration system and better insulation. Three generations of prototypes were built and tested in a climate chamber at Danish Technological Institute and the third generation showed very good performance: the energy consumption was measured to 2.215 kWh/day, which is a 47% reduction compared to the baseline. That was achieved by: 1) Improving the cold air cycling system including the air curtain. 2) Using the natural refrigerant R600a (isobutane) and the Danfoss NLE9KTK compressor, which has better efficiency compared to the compressor in the baseline product. 3) Using a box type condenser without fins (preventing dust build-up) and with a relatively high surface area. 4) Improving the insulation value of the plastic cabinet by reducing turbulence in the air gap between the plastic walls and improving the insulation value of the EPS moulded insulation surrounding the refrigeration system at the bottom of the cooler. 5) Preventing short-circuit of warm air around the condenser. 6) The improvements are cost efficient and will not add

Solution for Direct Solar Impingement Problem on Landsat-7 ETM+ Cooler Door During Cooler Outgas in Flight

Science.gov (United States)

Choi, Michael K.

1999-01-01

There was a thermal anomaly of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) radiative cooler cold stage during the cooler outgas phase in flight. With the cooler door in the outgas position and the outgas heaters enabled, the cold stage temperature increased to a maximum of 323 K when the spacecraft was in the sunlight, which was warmer than the 316.3 K upper set point of the outgas heater controller on the cold stage. Also, the outgas heater cycled off when the cold stage was warming up to 323 K. A corrective action was taken before the attitude of the spacecraft was changed during the first week in flight. One orbit before the attitude was changed, the outgas heaters were disabled to cool off the cold stage. The cold stage temperature increase was strongly dependent on the spacecraft roll and yaw. It provided evidence that direct solar radiation entered the gap between the cooler door and cooler shroud. There was a concern that the direct solar radiation could cause polymerization of hydrocarbons, which could contaminate the cooler and lead to a thermal short. After outgas with the cooler door in the outgas position for seven days, the cooler door was changed to the fully open position. With the cooler door fully open, the maximum cold stage temperature was 316.3 K when the spacecraft was in the sunlight, and the duty cycle of the outgas heater in the eclipse was the same as that in the sunlight. It provided more evidence that direct solar radiation had entered the gap between the cooler door and cooler shroud. Cooler outgas continued for seven more days, with the cooler door fully open. The corrective actions had prevented overheating of the cold stage and cold focal plane array (CFPA), which could damage these two components. They also minimized the risk of contamination on the cold stage, which could lead to a thermal short.

Evaluation on Cooling Performance of Containment Fan Cooler during Design Basis Accident with Loss of Offsite Power for Kori 3 and 4 Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Lee, Sung Bok; Lee, Sang Won [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of); Park, Young Chan [Atomic Creative Technology Co., LTD., Daejeon (Korea, Republic of)

2007-10-15

The purpose of this study is to evaluate cooling performance of containment fan cooler units and to review a technical background related to Generic Letter 96-06. In case that design basis accident (DBA) and loss of offsite power (LOOP) occurs, component cooling water (CCW) pumps cannot provide the cooling water source to fan cooler units while fan coolers coast down. Fan cooler units and CCW pumps are restarted by emergency diesel generator (EDG) operation and it takes about 30 seconds. In this scenario, before the EDG restarts and CCW flowrate is restored, heated air in the containment passes through coil of fan cooler units without cooling water source. In this situation, the boiling of water in the fan cooler units may occur. Restarting of CCW pumps may bring about condensation by injected cooling water and water hammer may occur. This thermal-hydraulic effect is sensitive to system configuration, i.e system pressure, containment pressure/temperature, EDG restarting time, etc. In this study, the evaluation of containment fan cooler units was performed for Kori 3 and 4 nuclear power plant.

Operation of a pond-cooler: the case of Berezovskaya GRES-1

Science.gov (United States)

Morozova, O. G.; Kamoza, T. L.; Koyupchenko, I. N.; Savelyev, A. S.; Pen, R. Z.; Veselkova, N. S.; Kudryavtsev, M. D.

2017-08-01

Pond-coolers at heat and nuclear power stations are natural-technological systems, so the program of their monitoring should include the effect made by the SRPS (state regional power station) on the pond ecosystem, including thermal discharge of cooling water. The objectives of this study were development and implementation of a monitoring program for the cooling pond of Berezovskaya SRPS-1 on the chemical and biological water quality indicators and identification of patterns of the thermal and hydrochemical regime when operating the progressive power plant (from 1996 to 2015). The quality of the cooling water of the pond-cooler BGRES-1 was studied under full-scale conditions by selecting and analyzing the water samples of the pond in accordance with the principles of complexity, systematic observation, and consistency of timing their conduct with the characteristic hydrological phases. Processing of the obtained array of monitoring data by methods of mathematical statistics makes it possible to identify the main factors affecting the water quality of the pond. The data on water quality obtained during their monitoring and mathematical processing over a long time interval are the scientific basis for forecasting the ecological state of the pond, which is necessary to economically ensure the efficient energy production and safety of water use. Recommendations proposed by these authors, including those partially already implemented, have been to prevent the development of eutrophication processes in the pond-cooler: the construction of a dam that cuts off the main peat massif and cleaning the river banks forming the cooling pond.

Experimental testing of the thermal performance of finned air coolers

International Nuclear Information System (INIS)

Imhof, A.; Keller, J.; Koelliker, A.

1988-05-01

Finned heat exchangers are often used as regenerators in heat recovery systems or as a heat source for heat pump installations. These exchangers are usually operating as air coolers. Heat is extracted from the air flowing through the heat exchanger. If the fin temperature lies below the dew point at the air inlet, water vapour may be condensed, increasing the thermal performance of the cooler. If the air/water heat exchanger is installed outdoors, the blower is usually mounted directly at the exchaner's case. In general this leads to non-ideal air flow conditions. For the sizing of such components the manufacturers dispose of design rules which are based either on theoretical models or on experiments using a uniform air stream. These rules which are mostly internal codes of the individual companies presumably do not take into account some non-ideal conditions such as an inhomogeneous air flow, a poorly sized blower or an increased pressure drop between the fins due to condensed water vapour. Moreover, these codes are possibly not sophisticated enough to enable a correct sizing of the products for any given condition of operation, especially in heat pumps operating under condensation conditions. Therfore, the Swiss Federal Institute for Reactor Research (EIR) carried out a research program dealing with the thermal performance of commercially available finned air coolers. The results give a strong evidence that the sizing of finned air coolers involving a phase change in one of the heat transfer fluids is not yet a procedure belonging to the common knowledge of most of the manufacturers. Moreover, the correct sizing of the blower is at least as important as the sizing of the finned exchanger itself. However, it is evident that there are companies on the Swiss market which use already reliable design tools. 25 refs., 81 figs., 12 tabs

The COOLER Code

DEFF Research Database (Denmark)

Siragusa, Mattia; Baiocco, Giorgio; Fredericia, Nina Pil Møntegaard

2017-01-01

COmputation of Local Electron Release (COOLER), a software program designed for dosimetry assessment at the cellular/subcellular scale, with a given distribution of administered low-energy electron-emitting radionuclides in cellular compartments, which remains a critical step in risk/benefit...... calculations with PARTRAC. Results from PARTRAC calculations on electron range, stopping power and residual energy versus traveled distance curves are presented and, when useful for implementation in COOLER, analytical fit functions are given. Example configurations for cells in different culture conditions (V...

Surface tension confined liquid cryogen cooler

Science.gov (United States)

Castles, Stephen H. (Inventor); Schein, Michael E. (Inventor)

1989-01-01

A cryogenic cooler is provided for use in craft such as launch, orbital, and space vehicles subject to substantial vibration, changes in orientation, and weightlessness. The cooler contains a small pore, large free volume, low density material to restrain a cryogen through surface tension effects during launch and zero-g operations and maintains instrumentation within the temperature range of 10 to 140 K. The cooler operation is completely passive, with no inherent vibration or power requirements.

Mitigation of Syngas Cooler Plugging and Fouling

Energy Technology Data Exchange (ETDEWEB)

Bockelie, Michael J. [Reaction Engineering International, Salt Lake City, UT (United States)

2015-06-29

This Final Report summarizes research performed to develop a technology to mitigate the plugging and fouling that occurs in the syngas cooler used in many Integrated Gasification Combined Cycle (IGCC) plants. The syngas cooler is a firetube heat exchanger located downstream of the gasifier. It offers high thermal efficiency, but its’ reliability has generally been lower than other process equipment in the gasification island. The buildup of ash deposits that form on the fireside surfaces in the syngas cooler (i.e., fouling) lead to reduced equipment life and increased maintenance costs. Our approach to address this problem is that fouling of the syngas cooler cannot be eliminated, but it can be better managed. The research program was funded by DOE using two budget periods: Budget Period 1 (BP1) and Budget Period 2 (BP2). The project used a combination of laboratory scale experiments, analysis of syngas cooler deposits, modeling and guidance from industry to develop a better understanding of fouling mechanisms and to develop and evaluate strategies to mitigate syngas cooler fouling and thereby improve syngas cooler performance. The work effort in BP 1 and BP 2 focused on developing a better understanding of the mechanisms that lead to syngas cooler plugging and fouling and investigating promising concepts to mitigate syngas cooler plugging and fouling. The work effort focused on the following: • analysis of syngas cooler deposits and fuels provided by an IGCC plant collaborating with this project; • performing Jet cleaning tests in the University of Utah Laminar Entrained Flow Reactor to determine the bond strength between an ash deposit to a metal plate, as well as implementing planned equipment modifications to the University of Utah Laminar Entrained Flow Reactor and the one ton per day, pressurized Pilot Scale Gasifier; • performing Computational Fluid Dynamic modeling of industrially relevant syngas cooler configurations to develop a better

Small high cooling power space cooler

Energy Technology Data Exchange (ETDEWEB)

Nguyen, T. V.; Raab, J.; Durand, D.; Tward, E. [Northrop Grumman Aerospace Systems Redondo Beach, Ca, 90278 (United States)

2014-01-29

The small High Efficiency pulse tube Cooler (HEC) cooler, that has been produced and flown on a number of space infrared instruments, was originally designed to provide cooling of 10 W @ 95 K. It achieved its goal with >50% margin when limited by the 180 W output ac power of its flight electronics. It has also been produced in 2 stage configurations, typically for simultaneously cooling of focal planes to temperatures as low as 35 K and optics at higher temperatures. The need for even higher cooling power in such a low mass cryocooler is motivated by the advent of large focal plane arrays. With the current availability at NGAS of much larger power cryocooler flight electronics, reliable long term operation in space with much larger cooling powers is now possible with the flight proven 4 kg HEC mechanical cooler. Even though the single stage cooler design can be re-qualified for those larger input powers without design change, we redesigned both the linear and coaxial version passive pulse tube cold heads to re-optimize them for high power cooling at temperatures above 130 K while rejecting heat to 300 K. Small changes to the regenerator packing, the re-optimization of the tuned inertance and no change to the compressor resulted in the increased performance at 150 K. The cooler operating at 290 W input power achieves 35 W@ 150 K corresponding to a specific cooling power at 150 K of 8.25 W/W and a very high specific power of 72.5 W/Kg. At these powers the cooler still maintains large stroke, thermal and current margins. In this paper we will present the measured data and the changes to this flight proven cooler that were made to achieve this increased performance.

Heat transfer and evaporative cooling in the function of pot-in-pot coolers

Science.gov (United States)

Chemin, Arsène; Levy Dit Vehel, Victor; Caussarieu, Aude; Plihon, Nicolas; Taberlet, Nicolas

2018-03-01

A pot-in-pot cooler is an affordable electricity-free refrigerator which uses the latent heat of vaporization of water to maintain a low temperature inside an inner compartment. In this article, we experimentally investigate the influence of the main physical parameters in model pot-in-pot coolers. The effect of the wind on the evaporation rate of the cooling fluid is studied in model experiments while the influence of the fluid properties (thermal conductivity, specific heat, and latent heat) is elucidated using a variety of cooling fluids (water, ethanol, and ether). A model based on a simplified heat conduction equation is proposed and is shown to be in good quantitative agreement with the experimental measurements.

Thermoelectric coolers as power generators

International Nuclear Information System (INIS)

Burke, E.J.; Buist, R.J.

1984-01-01

There are many applications where thermoelectric (TE) coolers can be used effectively as power generators. The literature available on this subject is scarce and very limited in scope. This paper describes the configuration, capability, limitations and performance of TE coolers to be used as power generators. Also presented are performance curves enabling the user to design the optimum TE module for any given power generation application

Advances in a high efficiency commercial pulse tube cooler

Science.gov (United States)

Zhang, Yibing; Li, Haibing; Wang, Xiaotao; Dai, Wei; Yang, Zhaohui; Luo, Ercang

2017-12-01

The pulse tube cryocooler has the advantage of no moving part at the cold end and offers a high reliability. To further extend its use in commercial applications, efforts are still needed to improve efficiency, reliability and cost effectiveness. This paper generalizes several key innovations in our newest cooler. The cooler consists of a moving magnet compressor with dual-opposed pistons, and a co-axial cold finger. Ambient displacers are employed to recover the expansion work to increase cooling efficiency. Inside the cold finger, the conventional flow straightener screens are replaced by a tapered throat between the cold heat exchanger and the pulse tube to strengthen its immunity to the working gas contamination as well as to simplify the manufacturing processes. The cold heat exchanger is made by copper forging process which further reduces the cost. Inside the compressor, a new gas bearing design has brought in assembling simplicity and running reliability. Besides the cooler itself, electronic controller is also important for actual application. A dual channel and dual driving mode control mechanism has been selected, which reduces the vibration to a minimum, meanwhile the cool-down speed becomes faster and run-time efficiency is higher. With these innovations, the cooler TC4189 reached a no-load temperature of 44 K and provided 15 W cooling power at 80K, with an input electric power of 244 W and a cooling water temperature of 23 ℃. The efficiency reached 16.9% of Carnot at 80 K. The whole system has a total mass of 4.3 kg.

Heat driven thermoacoustic cooler based on traveling-standing wave

International Nuclear Information System (INIS)

Kang Huifang; Zhou Gang; Li Qing

2010-01-01

This paper presents a heat driven thermoacoustic cooler system without any moving part. It consists of a thermoacoustic engine and a thermoacoustic cooler, and the former is the driving source of the latter. Both the engine and the cooler are located in one loop tube coupled with a resonator tube, and the acoustic power produced by the engine is used to drive the cooler directly. Both regenerators of the engine and the cooler are located in the near region of the pressure antinode, and operate in traveling-standing wave phase region. In the engine's regenerator, both components of the standing wave and the traveling wave realize the conversion from heat to acoustic energy. This improves the efficiency of the engine. In the cooler's regenerator, both components of the traveling wave and the standing wave pump heat from the cold end. This improves the efficiency of the cooler. At the operating point with a mean pressure of 22 bar, helium as working gas, a frequency of 234 Hz, and a heating power of 300 W, the experimental cooler provides a no-load temperature of -30 deg. C and a cooling power of 40 W at the cooling temperature of 0 deg. C. The total length of this cooler system is less than 1 m, which shows a good prospect for the domestic cooler system in room-temperature cooling such as food refrigeration and air-conditioning.

Optimising the operation of hybrid coolers by means of efficient control equipment; Optimierung der Betriebsweise von Hybridkuehlern durch effiziente Steuerungstechnik

Energy Technology Data Exchange (ETDEWEB)

Odrich, T.; Koenig, H. [Jaeggi/Guentner (Schweiz) AG, Trimbach (Switzerland)

2007-07-01

Due to its functional principle and design, the hybrid dry cooler holds a high potential for saving water and energy. Purely convective heat discharge during dry operation in the case of a high annual rate of utilisation, evaporative cooling during the wetting cycle at peak load times or high ambient temperatures and infinitely adjustable fan speed in both operating modes permit a very substantial recooling performance at low operating costs and with little space requirement. However, the efficiency of hybrid dry coolers depends to a large degree on how intelligently the cooling functions are controlled and on the control strategy. The present article demonstrates that the control strategy contributes decisively to minimising water and energy consumption and costs. Besides describing the actual functions of a hybrid cooler control system it presents a control strategy for automatic lowering of the setpoint and hence optimisation of the refrigeration process. It discusses the option of operating multiple hybrid coolers by means of a hydraulic network and presents an optimised control concept for this purpose which is based on a master control unit. In conclusion the study shows that hybrid coolers need their own optimised control unit if maximum savings in energy and water are to be achieved.

Dry coolers and air-condensing units (Review)

Science.gov (United States)

Milman, O. O.; Anan'ev, P. A.

2016-03-01

The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that

The Liquefaction of Hydrogen and Helium Using Small Coolers

International Nuclear Information System (INIS)

Green, Michael A.

2006-01-01

This report discusses the history of the liquefaction of hydrogen and helium using small coolers. This history dates form the 1960's when two stage GM coolers capable of reaching 7 K were used to liquefy helium and hydrogen by suing an added compressor and J-T circuit. Liquefaction using the added circuit failed to become mainstream because the J-T valve and heat exchanger clogged because of impurities in the gas being liquefied. Liquefaction using a GM cooler without an added J-T circuit proved to be difficult because the first stage was not used to pre-cool the gas coming to the second stage of the cooler. Once the gas being liquefied was pre-cooled using the cooler first stage, improvements in the liquefaction rates were noted. The advent of low temperature pulse tube cooler (down to 2.5 K) permitted one to achieve dramatic improvement is the liquefactions rates for helium. Similar but less dramatic improvements are expected for hydrogen as well. Using the PT-415 cooler, one can expect liquefaction rates of 15 to 20 liters per day for helium or hydrogen provided the heat leak into the cooler and the storage vessel is low. A hydrogen liquefier for MICE is presented at the end of this report

Sensitivity of Micromachined Joule-Thomson Cooler to Clogging Due to Moisture

NARCIS (Netherlands)

Cao, Haishan; Vanapalli, Srinivas; Holland, Herman J.; Vermeer, Cristian Hendrik; ter Brake, Hermanus J.M.

2015-01-01

A major issue in long-term operation of micromachined Joule-Thomson coolers is the clogging of the microchannels and/or the restriction due to the deposition of water molecules present in the working fluid. In this study, we present the performance of a microcooler operated with nitrogen gas with

Thermosyphon Cooler Hybrid System for Water Savings in an Energy-Efficient HPC Data Center: Modeling and Installation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Carter, Thomas; Liu, Zan; Sickinger, David; Regimbal, Kevin; Martinez, David

2017-02-01

The Thermosyphon Cooler Hybrid System (TCHS) integrates the control of a dry heat rejection device, the thermosyphon cooler (TSC), with an open cooling tower. A combination of equipment and controls, this new heat rejection system embraces the 'smart use of water,' using evaporative cooling when it is most advantageous and then saving water and modulating toward increased dry sensible cooling as system operations and ambient weather conditions permit. Innovative fan control strategies ensure the most economical balance between water savings and parasitic fan energy. The unique low-pressure-drop design of the TSC allows water to be cooled directly by the TSC evaporator without risk of bursting tubes in subfreezing ambient conditions. Johnson Controls partnered with the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories to deploy the TSC as a test bed at NREL's high-performance computing (HPC) data center in the first half of 2016. Located in NREL's Energy Systems Integration Facility (ESIF), this HPC data center has achieved an annualized average power usage effectiveness rating of 1.06 or better since 2012. Warm-water liquid cooling is used to capture heat generated by computer systems direct to water; that waste heat is either reused as the primary heat source in the ESIF building or rejected using evaporative cooling. This data center is the single largest source of water and power demand on the NREL campus, using about 7,600 m3 (2.0 million gal) of water during the past year with an hourly average IT load of nearly 1 MW (3.4 million Btu/h) -- so dramatically reducing water use while continuing efficient data center operations is of significant interest. Because Sandia's climate is similar to NREL's, this new heat rejection system being deployed at NREL has gained interest at Sandia. Sandia's data centers utilize an hourly average of 8.5 MW (29 million Btu/h) and are also one of the largest consumers of

Pulse tube coolers for Meteosat third generation

International Nuclear Information System (INIS)

Butterworth, James; Aigouy, Gérald; Chassaing, Clement; Debray, Benoît; Huguet, Alexandre

2014-01-01

Air Liquide's Large Pulse Tube Coolers (LPTC) will be used to cool the focal planes of the Infrared Sounder (IRS) and Flexible Combined Imager (FCI) instruments aboard the ESA/Eumetsat satellites Meteosat Third Generation (MTG). This cooler consists of an opposed piston linear compressor driving a pulse tube cold head and the associated drive electronics including temperature regulation and vibration cancellation algorithms. Preparations for flight qualification of the cooler are now underway. In this paper we present results of the optimization and qualification activities as well as an update on endurance testing

Radiant coolers - Theory, flight histories, design comparisons and future applications

Science.gov (United States)

Donohoe, M. J.; Sherman, A.; Hickman, D. E.

1975-01-01

Radiant coolers have been developed for application to the cooling of infrared detectors aboard NASA earth observation systems and as part of the Defense Meteorological Satellite Program. The prime design constraints for these coolers are the location of the cooler aboard the satellite and the satellite orbit. Flight data from several coolers indicates that, in general, design temperatures are achieved. However, potential problems relative to the contamination of cold surfaces are also revealed by the data. A comparison among the various cooler designs and flight performances indicates design improvements that can minimize the contamination problem in the future.

The Cooling of a Liquid Absorber using a Small Cooler

International Nuclear Information System (INIS)

Baynham, D.E.; Bradshaw, T.W.; Green, M.A.; Ishimoto, S.; Liggins, N.

2005-01-01

This report discusses the use of small cryogenic coolers for cooling the Muon Ionization Cooling Experiment (MICE) liquid cryogen absorbers. Since the absorber must be able contain liquid helium as well liquid hydrogen, the characteristics of the available 4.2 K coolers are used here. The issues associated with connecting two-stage coolers to liquid absorbers are discussed. The projected heat flows into an absorber and the cool-down of the absorbers using the cooler are presented. The warm-up of the absorber is discussed. Special hydrogen safety issues that may result from the use of a cooler on the absorbers are also discussed

Micro-cooler enhancements by barrier interface analysis

International Nuclear Information System (INIS)

Stephen, A.; Dunn, G. M.; Glover, J.; Oxley, C. H.; Bajo, M. Montes; Kuball, M.; Cumming, D. R. S.; Khalid, A.

2014-01-01

A novel gallium arsenide (GaAs) based micro-cooler design, previously analysed both experimentally and by an analytical Heat Transfer (HT) model, has been simulated using a self-consistent Ensemble Monte Carlo (EMC) model for a more in depth analysis of the thermionic cooling in the device. The best fit to the experimental data was found and was used in conjunction with the HT model to estimate the cooler-contact resistance. The cooling results from EMC indicated that the cooling power of the device is highly dependent on the charge distribution across the leading interface. Alteration of this charge distribution via interface extensions on the nanometre scale has shown to produce significant changes in cooler performance

Mid Infrared Instrument cooler subsystem test facility overview

Science.gov (United States)

Moore, B.; Zan, J.; Hannah, B.; Chui, T.; Penanen, K.; Weilert, M.

2017-12-01

The Cryocooler for the Mid Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) provides cooling at 6.2K on the instrument interface. The cooler system design has been incrementally documented in previous publications [1][2][3][4][5]. It has components that traverse three primary thermal regions on JWST: Region 1, approximated by 40K; Region 2, approximated by 100K; and Region 3, which is at the allowable flight temperatures for the spacecraft bus. However, there are several sub-regions that exist in the transition between primary regions and at the heat reject interfaces of the Cooler Compressor Assembly (CCA) and Cooler Control Electronics Assembly (CCEA). The design and performance of the test facility to provide a flight representative thermal environment for acceptance testing and characterization of the complete MIRI cooler subsystem are presented.

Cool down time optimization of the Stirling cooler

Science.gov (United States)

Xia, M.; Chen, X. P.; Y Li, H.; Gan, Z. H.

2017-12-01

The cooling power is one of the most important performances of a Stirling cooler. However, in some special fields, the cool down time is more important. It is a great challenge to improve the cool down time of the Stirling cooler. A new split Stirling linear cryogenic cooler SCI09H was designed in this study. A new structure of linear motor is used in the compressor, and the machine spring is used in the expander. In order to reduce the cool down time, the stainless-steel mesh of regenerator is optimized. The weight of the cooler is 1.1 kg, the cool down time to 80K is 2 minutes at 296K with a 250J thermal mass, the cooling power is 1.1W at 80K, and the input power is 50W.

Performance characterization of the TRW 35K pulse tube cooler

International Nuclear Information System (INIS)

Collins, S.A.; Johnson, D.L.; Smedley, G.T.; Ross, R.G. Jr.

1996-01-01

The TRW 35K pulse tube cooler is configured as an integral cooler, with the pulse tube attached perpendicular to a pair of compressors operating into a common compression chamber. The cooler was optimized for 35K operation and has a nominal cooling capacity of 850 mW at 35 K with a cooler input power of 200 W. It also provides 2 W of cooling at 60 K for 90 W of input power. The cooler was extensively characterized by JPL, measuring the thermal performance and the cooler-generated vibration and EMI as a function of piston stroke and offset position. The thermal performance was found to be quite sensitive to the piston offset position. The pulse tube parasitic conduction levels were also measured and shown to have a strong angular dependence relative to gravity. Magnetic shielding studies were performed to examine radiated magnetic emission levels from compressors with and without shielding

Variable-speed air-forced cooler technology

OpenAIRE

Siffring, Wolfgang

2016-01-01

Advanced air coolers are able to cool transformer oil more efficiently than older systems. Replacement or expansion of cooling plants by a new solution can lead to reduction of oil temperatures by several degrees and have a positive influence on the service lifetimes of oil and therefore transformers. Or, conversely, better coolers can – at the same oil temperatures – enhance the maximum performance of a transformer or allow it to operate at a higher average load. The upgrade or expansion of ...

Re-Condensation and Liquefaction of Helium and Hydrogen Using Coolers

International Nuclear Information System (INIS)

Green, Michael A.

2009-01-01

Coolers are used to cool cryogen free devices at temperatures from 5 to 30 K. Cryogen free cooling involves a temperature drop within the device being cooled and between the device and the cooler cold heads. Liquid cooling with a liquid cryogen distributed over the surface of a device combined with re-condensation can result in a much lower temperature drop between the cooler and the device being cooled. The next logical step beyond simple re-condensation is using a cooler to liquefy the liquid cryogen in the device. A number of tests of helium liquefaction and re-condensation of helium have been run using a pulse tube cooler in the drop-in mode. This report discusses the parameter space over which re-condensation and liquefaction for helium and hydrogen can occur.

Improvement In The COP Of Thermoelectric Cooler

Directory of Open Access Journals (Sweden)

Jatin Patel

2015-08-01

Full Text Available This paper described the study for heat transfer through thermoelectric cooler TEC by use of multistage thermoelectric module. To satisfy the heat dissipation of modern electronic element thermal designers have to increase fin area and fan speed to improve its cooling capacity. However the increase of fin area is restricted by the space. Besides the increase of fan speed would induce noise which damages human health. So air cooling by fan is hardly to meet the requirement of modern electronic component. Recently thermoelectric cooler TEC is applied to electronic cooling with the advantages of small size quietness and reliability. A typical thermoelectric cooler consists of p-type and n-type semiconductor pellets connected electrically in series and sandwiched between two ceramic substrates. Whenever direct current passes through the circuit it causes temperature differential between TEC sides. As a result one face of TEC which is called cold side will be cooled while its opposite face which is called hot side is simultaneously heated. The main problem over the use of TEC is the limited COP and its thermal performance. But these can be eliminated by use of multistage thermoelectric cooler.

Conversion of St. Marys conventional grate cooler at the Bowmanville plant

Energy Technology Data Exchange (ETDEWEB)

Keefe, B.P. (Fuller Co., Bethlehem, PA (United States))

1993-11-01

Fuller Company has recently retrofitted the largest operating clinker cooler in North America with its CFG (Controlled Flow Grate) system. The cooler conversion was made to the St. Mary's Cement's 5000 mtpd Folax grate cooler at the Bowmanville plant. The project included conversion of the entire first drive section to Fuller's new cooler design featuring its increased flow resistance grate plates, a maintenance-friendly air distribution system, and a new hydraulic drive unit. As a result of the cooler conversion, significant power and fuel savings were made possible for an already efficient and modern cement producing facility. (author)

Development of the Sandia Cooler

Energy Technology Data Exchange (ETDEWEB)

Johnson, Terry Alan [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Koplow, Jeffrey P. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Staats, Wayne Lawrence [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Curgus, Dita Brigitte [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Leick, Michael Thomas. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Matthew, Ned Daniel [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Zimmerman, Mark D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Arienti, Marco [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Gharagozloo, Patricia E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hecht, Ethan S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Spencer, Nathan A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Vanness, Justin William. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Gorman, Ryan [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2013-12-01

This report describes an FY13 effort to develop the latest version of the Sandia Cooler, a breakthrough technology for air-cooled heat exchangers that was developed at Sandia National Laboratories. The project was focused on fabrication, assembly and demonstration of ten prototype systems for the cooling of high power density electronics, specifically high performance desktop computers (CPUs). In addition, computational simulation and experimentation was carried out to fully understand the performance characteristics of each of the key design aspects. This work culminated in a parameter and scaling study that now provides a design framework, including a number of design and analysis tools, for Sandia Cooler development for applications beyond CPU cooling.

Performance of an irreversible quantum Ericsson cooler at low temperature limit

International Nuclear Information System (INIS)

Wu Feng; Chen Lingen; Wu Shuang; Sun Fengrui

2006-01-01

The purpose of this paper is to investigate the effect of quantum properties of the working medium on the performance of an irreversible quantum Ericsson cooler with spin-1/2. The cooler is studied with the losses of heat resistance, heat leakage and internal irreversibility. The optimal relationship between the dimensionless cooling load R * versus the coefficient of performance ε for the irreversible quantum Ericsson cooler is derived. In particular, the performance characteristics of the cooler at the low temperature limit are discussed

Low Energy Electron Cooler for NICA Booster

CERN Document Server

Denisov, A P

2017-01-01

BINP has developed an electron cooler to increase the ion accumulation efficiency in the NICA (Nuclotron-based Ion Collider fAcility) heavy ion booster (JINR, Dubna). Adjustment of the cooler magnetic system provides highly homogeneous magnetic field in the cooling section B trans/B long ≤ 4∙10-5 which is vital for efficient electron cooling. First experiments with an electron beam performed at BINP demonstrated the target DC current of 500 mA and electron energy 6 keV.

Microsystem Cooler Concept Developed and Being Fabricated

Science.gov (United States)

Moran, Matthew E.

2005-01-01

A patented microsystem cooler concept has been developed by the NASA Glenn Research Center. It incorporates diaphragm actuators to produce the Stirling refrigeration cycle within a planar configuration compatible with the thermal management of electronics, sensors, optical and radiofrequency systems, microarrays, and other microsystems. The microsystem cooler is most suited to volume-limited applications that require cooling below the ambient or sink temperature. Johns Hopkins University Applied Physics Laboratory is conducting development testing and fabrication of a prototype under a grant from Glenn.

Microsystem Cooler Development

Science.gov (United States)

Moran, Matthew E.; Wesolek, Danielle M.; Berhane, Bruk T.; Rebello, Keith J.

2004-01-01

A patented microsystem Stirling cooler is under development with potential application to electronics, sensors, optical and radio frequency (RF) systems, microarrays, and other microsystems. The microsystem Stirling cooler is most suited to volume-limited applications that require cooling below the ambient or sink temperature. Primary components of the planar device include: two diaphragm actuators that replace the pistons found in traditional-scale Stirling machines; and a micro-regenerator that stores and releases thermal energy to the working gas during the Stirling cycle. The use of diaphragms eliminates frictional losses and bypass leakage concerns associated with pistons, while permitting reversal of the hot and cold sides of the device during operation to allow precise temperature control. Three candidate microregenerators were custom fabricated for initial evaluation: two constructed of porous ceramic, and one made of multiple layers of nickel and photoresist in an offset grating pattern. An additional regenerator was prepared with a random stainless steel fiber matrix commonly used in existing Stirling machines for comparison to the custom fabricated regenerators. The candidate regenerators were tested in a piezoelectric-actuated test apparatus designed to simulate the Stirling refrigeration cycle. In parallel with the regenerator testing, electrostatically-driven comb-drive diaphragm actuators for the prototype device have been designed for deep reactive ion etching (DRIE) fabrication.

Development of a 15 K hydrogen-based sorption cooler

NARCIS (Netherlands)

Burger, Johannes Faas; Holland, Herman J.; Meijer, R.J.; Linder, M.; ter Brake, Hermanus J.M.

2010-01-01

At the University of Twente, a 15 K hydrogen-based sorption cooler is under development, which has no moving parts and, therefore, is essentially vibration-free. Moreover, it has the potential of a very long life. Although the cooler may operate standalone, it is designed to precool a helium-based

Technical assistance for the evaluation of fluid loop components (Peltier cooler)

Science.gov (United States)

Best, R.; Biemann, W.; Bosch, R.; Hingst, U.; Kreeb, H.; Mueller, W.

1980-07-01

The application of Peltier elements for refrigeration with source temperature control and heat rejection to a fluid loop was investigated using commercially available Peltier cooling elements. Peltier element performance with Peltier elements integrated into a cooler unit, investigation of possible temperature stabilization of the source side of the Peltier cooler arrangement, investigation of the necessary power supply and the power consumption for certain requirements for temperature range and heat load at the source, and investigation of mounting and integration aspects are discussed. Analytical calculations for the performance of Peltier elements in a cooler unit are relevant for a power supply, a temperature regulation system, and the design of bread board cooler unit.

Study of containment air cooler capacity in steam air environment during accident conditions

International Nuclear Information System (INIS)

Kansal, M.; Mohan, N.; Bhawal, R.N.; Bajaj, S.S.

2002-01-01

Full text: The air coolers are provided for controlling the temperature in the reactor building during normal operation. These air coolers also serve as the main heat sink for the removal of energy from high enthalpy air-steam mixture expected in reactor building under accident conditions. A subroutine COOLER has been developed to estimate the heat removal rate of the air coolers at high temperature and steam conditions. The subroutine COOLER has been attached with the code PACSR (post accident containment system response) used for containment pressure temperature calculation. The subroutine was validated using design parameters at normal operating condition. A study was done to estimate the heat removal rate for some postulated accident conditions. The study reveals that, under accident conditions, the heat removal rate of air coolers increases several times compared with normal operating conditions

Heat jettisoning from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water; Waermeabwurf aus einer solarthermisch getriebenen LiBr- H{sub 2}O Absorptionskaeltemaschine durch gepulstes Bespruehen eines Trockenkuehlers mit Wasser

Energy Technology Data Exchange (ETDEWEB)

Gantenbein, P.; Helfenberger, R.; Frank, E.

2010-07-01

This short, illustrated final report discusses the removal of heat from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water. The reduction of electricity consumption for room cooling using conventional chillers is examined. Heat dissipation using open cooling towers and the disadvantages encountered are compared with heat dissipation using a dry cooler with heat-exchanger and fans. Additional evaporation cooling achieved by spraying the heat exchanger with water is described and discussed. The results of measurements made at the Institute for Solar Technology in Rapperswil, Switzerland, are presented and discussed.

Thermal analysis for steering cooler and hose to reduce product design cost

International Nuclear Information System (INIS)

Wang, L.

2002-01-01

This paper describes the procedures to conduct a thermal analysis to determine the right sizing of a typical steering cooler and hose system. A commercial CFD (Computational Fluid Dynamics) package, Star-CD, was used to solve the heat transfer problem. Instead of modelling the actual finned cooler, a porous media box cooler was simulated in the analysis and the effective conductivity for the box cooler was obtained through the simulation of a submodel, which was consisted of one layer of the aluminium fin and two layers of air around it. A user-defined subroutine was used in the simulation to correctly represent the contact area in the box cooler. In addition, a comparison between the numerical results and the experimental testing was provided. The good agreement between them validates the methodology used in this analysis. (author)

A numerical study on the usage of phase change material (PCM) to prolong compressor off period in a beverage cooler

International Nuclear Information System (INIS)

Ezan, Mehmet Akif; Ozcan Doganay, Esra; Yavuz, Fazil Erinc; Tavman, Ismail Hakkı

2017-01-01

Highlights: • A 3D transient model is developed in a commercial CFD solver for vertical beverage cooler with PCM. • PCM slab is directly contacted with the airflow. • Regarding the run-time ratio best performance is achieved with 6 mm PCM slab. • Due to thermal inertia within the PCM domain, the VBC preserves its temperature for a long time. - Abstract: This study numerically investigates the influence of integration of a phase change material (PCM) slab inside a vertical beverage cooler (VBC) on the energy consumption, the thermal stability and flow characteristics of air inside the cooler. The PCM, water, slab is placed on the rear side of the flat plate roll bond evaporator with five different thicknesses, such as 2, 4, 6, 8, and 10 mm. In the current work, transient numerical analyses are performed with ANSYS-FLUENT software for an empty cooler. To simulate the on/off controller of the cooling system a dedicated user-defined-function (UDF) is implemented in the software. Unlike the counterparts in the recent literature, instead of reducing the problem into a 1D or 2D lumped models a three-dimensional cooler domain is simulated in a commercial CFD solver. The predictions are compared with the experimental measurement for the cooler without PCM regarding the transient variations of the mean temperatures of evaporator surface and the indoor air. Consequently, the parametric set of analyses deduced that the PCM integration into the cooler enhances the cooling performance of the VBC by prolonging compressor off duration. Moreover, during the compressor off time, PCM preserves the air temperature inside the refrigerated space in the desired range by limiting the sudden temperature increments.

Calculations of air cooler for new subsonic wind tunnel

Science.gov (United States)

Rtishcheva, A. S.

2017-10-01

As part of the component development of TsAGI’s new subsonic wind tunnel where the air flow velocity in the closed test section is up to 160 m/sec hydraulic and thermal characteristics of air cooler are calculated. The air cooler is one of the most important components due to its highest hydraulic resistance in the whole wind tunnel design. It is important to minimize its hydraulic resistance to ensure the energy efficiency of wind tunnel fans and the cost-cutting of tests. On the other hand the air cooler is to assure the efficient cooling of air flow in such a manner as to maintain the temperature below 40 °C for seamless operation of measuring equipment. Therefore the relevance of this project is driven by the need to develop the air cooler that would demonstrate low hydraulic resistance of air and high thermal effectiveness of heat exchanging surfaces; insofar as the cooling section must be given up per unit time with the amount of heat Q=30 MW according to preliminary evaluations. On basis of calculation research some variants of air cooler designs are proposed including elliptical tubes, round tubes, and lateral plate-like fins. These designs differ by the number of tubes and plates, geometrical characteristics and the material of finned surfaces (aluminium or cooper). Due to the choice of component configurations a high thermal effectiveness is achieved for finned surfaces. The obtained results form the basis of R&D support in designing the new subsonic wind tunnel.

6D “Garren” snake cooler and ring cooler for µ{sup ±} cooling of a muon collider

Energy Technology Data Exchange (ETDEWEB)

Ding, X., E-mail: xding@bnl.gov [UCLA, Los Angeles, CA 90095 (United States); Berg, J.S. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Cline, D. [UCLA, Los Angeles, CA 90095 (United States); Garren, Al [Particle Beam Lasers, Inc., Northridge, CA 91324 (United States); Kirk, H.G. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

2014-12-21

Six dimensional cooling of large emittance µ{sup +} and µ{sup −} beams is required in order to obtain the desired luminosity for a muon collider. In our previous study, we demonstrated that a 6D “Garren” ring cooler using both dipoles and solenoids in four 90{sup 0} achromatic arcs can give substantial cooling in all six phase space dimensions. In this paper, we describe the injection/extraction requirements of this four-sided ring. We also present the performance of an achromat-based 6D “Garren” snake cooler. The achromatic design permits the design to easily switch between a closed ring and a snaking geometry on injection or extraction from the ring.

Inter-cooler in solar-assisted refrigeration system: Theory and experimental verification

Directory of Open Access Journals (Sweden)

Zheng Hui-Fan

2015-01-01

Full Text Available An inter-cooler in the solar-assisted refrigeration system was investigated experimentally and theoretically, and the theoretical prediction was fairly in good agreement with the experimental data. The influence of pipe diameter, tooth depth, and spiral angle of inter-cooler on the performance of the refrigerant system was analyzed. It was concluded that heat transfer is influenced deeply by the structure parameters of inter-cooler, and the heat transfer capacity increases with tooth depth and spiral angle increasing, and decreases with tooth apex angle increasing.

Transient Air Infiltration/Exfiltration in Walk-In Coolers

Energy Technology Data Exchange (ETDEWEB)

Faramarzi, Ramin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Navaz, H. K. [Kettering University; Kamensky, K. [Michigan State University

2018-03-01

Walk-in coolers are room-sized, insulated, and refrigerated compartments for food product storage. Walk-ins have areas equal or below 280 m2 (3,000 ft2), and are classified either as coolers operating above 0 degrees C (32 degrees F) (medium-temperature) to store fresh fruit, vegetables, and dairy products, or freezers that operate below 0 degrees C (32 degrees F) (low-temperature) to meet health and safety standards of frozen food products. Walk-ins are typically found in restaurants as well as small- and medium-to-large grocery stores or supermarkets.

Laser pumping of ions in a cooler buncher

Energy Technology Data Exchange (ETDEWEB)

Cheal, B., E-mail: bradley.cheal@manchester.ac.uk [University of Manchester (United Kingdom); Baczynska, K. [University of Birmingham, School of Physics and Astronomy (United Kingdom); Billowes, J.; Campbell, P. [University of Manchester (United Kingdom); Eronen, T. [University of Jyvaeskylae, Department of Physics (Finland); Forest, D. H. [University of Birmingham, School of Physics and Astronomy (United Kingdom); Kessler, T.; Moore, I. D. [University of Jyvaeskylae, Department of Physics (Finland); Rueffer, M. [University of Birmingham, School of Physics and Astronomy (United Kingdom); Tordoff, B. [University of Manchester (United Kingdom); Tungate, G. [University of Birmingham, School of Physics and Astronomy (United Kingdom); Aystoe, J. [University of Jyvaeskylae, Department of Physics (Finland)

2008-01-15

Optical experiments at the IGISOL isotope separator facility, Jyvaeskylae, have for many years benefited from the introduction of an ion beam cooler. The device, a gas-filled RF quadrupole, reduces the emittance and longitudinal energy spread of the ion beam. Very recently, use has been made of the axial confinement of slowly travelling ions at the end of the cooler to redistribute the electronic populations through efficient laser excitation. Such a technique has proved beneficial to laser spectroscopic measurements and is a precursor to using the method to polarize the ion beam.

The Optimum Selection and Drawing Output Program Development of Shell and Tube Type Oil Cooler

International Nuclear Information System (INIS)

Lee, Y. B.; Kim, T. S.; Ko, J. M

2007-01-01

Shell and Tube type Oil Cooler is widely used for hydraulic presses, die casting machines, generation equipments, machine tools and construction heavy machinery. Temperature of oil in the hydraulic system changes viscosity and thickness of oil film. They have a bad effect to performance and lubrication of hydraulic machinery, so it is important to know exactly the heat exchanging efficiency of oil cooler for controlling oil temperature. But most Korean manufacturers do not have test equipment for oil cooler, so they cannot carry out the efficiency test of oil cooler and it is impossible to verify its performance. This paper includes information of construction of necessary utilities for oil cooler test and design and manufacture of test equipment. One can select the optimum product by obtaining performance data through tests of various kinds of oil coolers. And also the paper developed a program which can be easily used for design of 2D and 3D drawings of oil cooler

The performance evaluation of a micro/nano-scaled cooler working with an ideal Bose gas

International Nuclear Information System (INIS)

Guo, Juncheng; Su, Guozhen; Chen, Jincan

2012-01-01

Based on the size effect of a confined ideal Bose gas, the design concept of a quantum cooler is originally put forward. The cooler consists of two long tubes with the same length but different sizes of cross section, which are filled up with the ideal Bose gas, and is operated between two heat reservoirs. Expressions for the refrigeration rate and coefficient of performance (COP) of the cooler are derived. The effects of the size effect on the refrigeration rate and COP are discussed. The general performance characteristics of the cooler are revealed. -- Highlights: ► The design concept of a quantum cooler is originally put forward. ► Expressions for the refrigeration rate and coefficient of performance (COP) of the cooler are derived. ► The effects of the size effect on the refrigeration rate and COP are discussed. ► The general performance characteristics of the cooler are revealed. ► The results obtained are more general and significant than those in the current literature.

Investigation of the vibration and EMC characteristics of miniature Stirling electric coolers for space applications

Science.gov (United States)

Kondratjev, V.; Gostilo, V.; Owens, anb A.

2017-08-01

We present the results of an investigation into the detrimental effects that electromechanical coolers can have on the spectral performance of compact, large volume HPGe spectrometers for space applications. Both mechanical vibration and electromagnetic pickup effects were considered, as well as a comparative assessment between three miniature Stirling cycle coolers—two Ricor model K508 coolers and one Thales model RM3 cooler. In spite of the limited number of coolers tested, the following conclusions can be made. There are significant differences in the vibration characteristics not only between the various types of cooler but also between coolers of the same type. It was also found that compared to the noise induced by mechanical vibrations, electromagnetic interference emanating from the embedded controllers does not significantly impact the energy resolution of detectors.

Evaporative Air Coolers Optimization for Energy Consumption Reduction and Energy Efficiency Ratio Increment

OpenAIRE

Leila Torkaman; Nasser Ghassembaglou

2015-01-01

Significant quota of Municipal Electrical Energy consumption is related to Decentralized Air Conditioning which is mostly provided by evaporative coolers. So the aim is to optimize design of air conditioners to increase their efficiencies. To achieve this goal, results of practical standardized tests for 40 evaporative coolers in different types collected and simultaneously results for same coolers based on one of EER (Energy Efficiency Ratio) modeling styles are figured ...

20 K continuous cycle sorption coolers for the Planck flight mission

Science.gov (United States)

Bhandari, P.; Prina, M.; Bowman, R. C., Jr.; Paine, C.; Pearson, D.; Nash, A.

2003-01-01

In this paper we present the level of maturity of the hydrogen sorption cooler technology at JPL by describing the design and how it has been validated at the subsystem and system levels. In addition, we will describe how such systems could be advantageously used for other space missions with similar needs and cooler attributes.

Cryogenic cooler thermal coupler

International Nuclear Information System (INIS)

Green, K.E.; Talbourdet, J.A.

1984-01-01

A thermal coupler assembly mounted to the coldfinger of a cryogenic cooler which provides improved thermal transfer between the coldfinger and the detector assembly mounted on the dewar endwell. The thermal coupler design comprises a stud and spring-loaded cap mounted on the coldfinger assembly. Thermal transfer is made primarily through the air space between the cap and coldwell walls along the radial surfaces. The cap is spring loaded to provide thermal contact between the cap and endwell end surfaces

Material Selection for Competition–A Case Study for Air Coolers

Directory of Open Access Journals (Sweden)

Luma A. H. Al Kindi

2018-02-01

Full Text Available Competition is one of the most important challenges that is facing the marketing of industrial products in today's markets. In this research study of the impact of material selection factor for air coolers of different materials is applied. Investigation on the air cooler windows which are part of the body of air coolers is conducted. Corrosion resistance, thermal conductivity, strength of material, weight, shape, cost and manufacturing process are the factors that are applied and calculated on three types of materials Aluminum, Galvanized steel and polypropylene. The physical properties of the three mentioned materials are used to calculate Merit Index .The corrosion average, according to Tafel Method depending the corrosion current and adopting contactors for the anodic and cathodic metals behaviors is performed. ANSYS is adopted using the three samples for the selected materials Aluminum, Galvanized steel and polypropylene to measure maximum stress and deflection are measured. Accordingly, the results are compared to choose the best alternative. It is observed that the polypropylene is the best choice depending three factors while the aluminum material is better depending two factors and the galvanized steel is regarded as the best in only one factor, the rest factors are identical when choosing  an alternative material for manufacturing the air cooler windows.

Performance Analysis of Joule-Thomson Cooler Supplied with Gas Mixtures

Science.gov (United States)

Piotrowska, A.; Chorowski, M.; Dorosz, P.

2017-02-01

Joule-Thomson (J-T) cryo-coolers working in closed cycles and supplied with gas mixtures are the subject of intensive research in different laboratories. The replacement of pure nitrogen by nitrogen-hydrocarbon mixtures allows to improve both thermodynamic parameters and economy of the refrigerators. It is possible to avoid high pressures in the heat exchanger and to use standard refrigeration compressor instead of gas bottles or high-pressure oil free compressor. Closed cycle and mixture filled Joule-Thomson cryogenic refrigerator providing 10-20 W of cooling power at temperature range 90-100 K has been designed and manufactured. Thermodynamic analysis including the optimization of the cryo-cooler mixture has been performed with ASPEN HYSYS software. The paper describes the design of the cryo-cooler and provides thermodynamic analysis of the system. The test results are presented and discussed.

Oxide-cathode activation and surface temperature calculation of electron cooler

International Nuclear Information System (INIS)

Li Jie; Yang Xiaodong; Mao Lijun; Li Guohong; Yuan Youjin; Liu Zhanwen; Zhang Junhui; Yang Xiaotian; Ma Xiaoming; Yan Tailai

2011-01-01

The pollution on electron gun ceramic insulation of electron cooler restricted the operation of electron cooler at HIRFL-CSR main ring. To cool and accumulate ion beam well, the pollution was cleared and a new oxide-coated cathode was assembled. The processes of cathode replacement,vacuum chamber baking-out, and thermal decomposition of coating binders and alkaline earth metal carbonates, and cathode activation are presented. The electron gun perveance of 10.6 μA/V 1.5 was attained under the heating power of 60 W. The typical surface temperature of oxide-coated cathode that is calculated through grey-body radiation is 1 108 K which shows a comparable result to the experimental measurement 1 078 K. The perveance growth of electron gun during the electron cooler operation is also explained by partial activation of the cathode. (authors)

USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

Science.gov (United States)

Weaver, H.L.; Campbell, G.S.

1985-01-01

Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

MEMS Stirling Cooler Development Update

Science.gov (United States)

Moran, Matthew E.; Wesolek, Danielle

2003-01-01

This presentation provides an update on the effort to build and test a prototype unit of the patented MEMS Stirling cooler concept. A micro-scale regenerator has been fabricated by Polar Thermal Technologies and is currently being integrated into a Stirling cycle simulator at Johns Hopkins University Applied Physics Laboratory. A discussion of the analysis, design, assembly, and test plans for the prototype will be presented.

Design, construction, and measurement of a large solar powered thermoacoustic cooler

Science.gov (United States)

Chen, Reh-Lin

2001-07-01

A device based on harnessing concentrated solar power in combination with using thermoacoustic principles has been built, instrumented, and tested. Its acoustic power is generated by solar radiation and is subsequently used to pump heat from external loads. The direct conversion between thermal and mechanical energy without going through any electronic stage makes the mechanism simple. Construction of the solar collector is also rather unsophisticated. It was converted from a 10-ft satellite dish with aluminized Mylar glued on the surface. The thermoacoustic device was mounted on the dish with its engine's hot side positioned near the focus of the parabolic dish, about 1 meter above the center of the dish. A 2-dimensional solar tracking system was built, using two servo motors to position the dish at pre-calculated coordinates. The solar powered thermoacoustic cooler is intended to be used where solar power is abundant and electricity may not be available or reliable. The cooler provides cooling during solar availability. Cooling can be maintained by the latent heat of ice when solar power is unattainable. The device has achieved cooling although compromised by gas leakage and thermal losses and was not able to provide temperatures low enough to freeze water. Improvements of the device are expected through modifications suggested herein.

The making of automation air fiddling unit (AHU) for G 71 cooler system

International Nuclear Information System (INIS)

Suripto

2003-01-01

A design of the making automation of air handling unit (AHU) for G. 71 cooler system at the design it has been conducted AHU operational time programming for G. 71 cooler system, when applied if will operate as programmed. flopefully, it mill save electric power and the dependency to the operator can be reduced significantly therefore it will increase efficiency and optimization in the usage of the cooler system. At the and if will reduce and save operational cost mainly in maintenance cost

CFD study of a simple orifice pulse tube cooler

Science.gov (United States)

Zhang, X. B.; Qiu, L. M.; Gan, Z. H.; He, Y. L.

2007-05-01

Pulse tube cooler (PTC) has the advantages of long-life and low vibration over the conventional cryocoolers, such as G-M and Stirling coolers because of the absence of moving parts in low temperature. This paper performs a two-dimensional axis-symmetric computational fluid dynamic (CFD) simulation of a GM-type simple orifice PTC (OPTC). The detailed modeling process and the general results such as the phase difference between velocity and pressure at cold end, the temperature profiles along the wall as well as the temperature oscillations at cold end with different heat loads are presented. Emphases are put on analyzing the complicated phenomena of multi-dimensional flow and heat transfer in the pulse tube under conditions of oscillating pressure. Swirling flow pattern in the pulse tube is observed and the mechanism of formation is analyzed in details, which is further validated by modeling a basic PTC. The swirl causes undesirable mixing in the thermally stratified fluid and is partially responsible for the poor overall performance of the cooler, such as unsteady cold-end temperature.

Modeling of Hydrate Formation Mode in Raw Natural Gas Air Coolers

Science.gov (United States)

Scherbinin, S. V.; Prakhova, M. Yu; Krasnov, A. N.; Khoroshavina, E. A.

2018-05-01

Air cooling units (ACU) are used at all the gas fields for cooling natural gas after compressing. When using ACUs on raw (wet) gas in a low temperature condition, there is a danger of hydrate plug formation in the heat exchanging tubes of the ACU. To predict possible hydrate formation, a mathematical model of the air cooler thermal behavior used in the control system shall adequately calculate not only gas temperature at the cooler's outlet, but also a dew point value, a temperature at which condensation, as well as the gas hydrate formation point, onsets. This paper proposes a mathematical model allowing one to determine the pressure in the air cooler which makes hydrate formation for a given gas composition possible.

Micro-coolers fabricated as a component in an integrated circuit

International Nuclear Information System (INIS)

Glover, James; Oxley, Chris H; Khalid, Ata; Cumming, David; Stephen, Alex; Dunn, Geoff

2015-01-01

The packing density and power capacity of integrated electronics is increasing resulting in higher thermal flux densities. Improved thermal management techniques are required and one approach is to include thermoelectric coolers as part of the integrated circuit. An analysis will be described showing that the supporting substrate will have a large influence on the cooling capacity of the thermoelectric cooler. In particular, for materials with a low ZT figure of merit (for example gallium arsenide (GaAs) based compounds) the substrate will have to be substantially thinned to obtain cooling, which may preclude the use of thermoelectric coolers, for example, as part of a GaAs based integrated circuit. Further, using experimental techniques to measure only the small positive cooling temperature difference (ΔT) between the anode (T h ) and the cathode (T c ) contacts can be misinterpreted as cooling when in fact it is heating. (paper)

Initial operation of cooler ring, TARN II

International Nuclear Information System (INIS)

Katayama, T.; Chida, K.; Honma, T.

1989-01-01

TARN II is a heavy ion cooler synchrotron for the studies of accelerator, atomic and nuclear physics, presently being constructed at the Institute for Nuclear Study, University of Tokyo. Its maximum energy is 370 MeV/u for the ions of a charge to mass ratio of q/A = 0.5, corresponding to a magnetic rigidity of 6.1 T·m. The circumference is 77.76 m, just 17 times the extraction orbit of injector cyclotron. Six long straight sections, 4.20 m in length each, are used for the beam injection, extraction, electron cooler and RF accelerating cavity, respectively. At the beginning of 1989, the first experiment of beam injection has been performed successfully with use of 28 MeV α particles. In this paper, the status and initial results of operation of TARN II are presented. (author)

3-D thermal hydraulic analysis of transient heat removal from fast reactor core using immersion coolers

International Nuclear Information System (INIS)

Chvetsov, I.; Volkov, A.

2000-01-01

For advanced fast reactors (EFR, BN-600M, BN-1600, CEFR) the special complementary loop is envisaged in order to ensure the decay heat removal from the core in the case of LOF accidents. This complementary loop includes immersion coolers that are located in the hot reactor plenum. To analyze the transient process in the reactor when immersion coolers come into operation one needs to involve 3-D thermal hydraulics code. Furthermore sometimes the problem becomes more complicated due to necessity of simulation of the thermal hydraulics processes into the core interwrapper space. For example on BN-600M and CEFR reactors it is supposed to ensure the effective removal of decay heat from core subassemblies by specially arranged internal circulation circuit: 'inter-wrapper space'. For thermal hydraulics analysis of the transients in the core and in the whole reactor including hot plenum with immersion coolers and considering heat and mass exchange between the main sodium flow and sodium that moves in the inter-wrapper space the code GRIFIC (the version of GRIF code family) was developed in IPPE. GRIFIC code was tested on experimental data obtained on RAMONA rig under conditions simulating decay heat removal of a reactor with the use of immersion coolers. Comparison has been made of calculated and experimental result, such as integral characteristics (flow rate through the core and water temperature at the core inlet and outlet) and the local temperatures (at thermocouple location) as well. In order to show the capabilities of the code some results of the transient analysis of heat removal from the core of BN-600M - type reactor under loss-of-flow accident are presented. (author)

Modeling of a regenerative indirect evaporative cooler for a desiccant cooling system

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Reinholdt, Lars O.

This paper presents a numerical study of a regenerative indirect evaporative cooler, the so-called Dew Point Cooler (DPC), which is part of a Desiccant Cooling system that may both dehumidify and cool humid air. The DPC model is based on first principles using a 1D finite volume scheme...

MEMS based shock pulse detection sensor for improved rotary Stirling cooler end of life prediction

Science.gov (United States)

Hübner, M.; Münzberg, M.

2018-05-01

The widespread use of rotary Stirling coolers in high performance thermal imagers used for critical 24/7 surveillance tasks justifies any effort to significantly enhance the reliability and predictable uptime of those coolers. Typically the lifetime of the whole imaging device is limited due to continuous wear and finally failure of the rotary compressor of the Stirling cooler, especially due to failure of the comprised bearings. MTTF based lifetime predictions, even based on refined MTTF models taking operational scenario dependent scaling factors into account, still lack in precision to forecast accurately the end of life (EOL) of individual coolers. Consequently preventive maintenance of individual coolers to avoid failures of the main sensor in critical operational scenarios are very costly or even useless. We have developed an integrated test method based on `Micro Electromechanical Systems', so called MEMS sensors, which significantly improves the cooler EOL prediction. The recently commercially available MEMS acceleration sensors have mechanical resonance frequencies up to 50 kHz. They are able to detect solid borne shock pulses in the cooler structure, originating from e.g. metal on metal impacts driven by periodical forces acting on moving inner parts of the rotary compressor within wear dependent slack and play. The impact driven transient shock pulse analyses uses only the high frequency signal <10kHz and differs therefore from the commonly used broadband low frequencies vibrational analysis of reciprocating machines. It offers a direct indicator of the individual state of wear. The predictive cooler lifetime model based on the shock pulse analysis is presented and results are discussed.

Boiling process in oil coolers on porous elements

Directory of Open Access Journals (Sweden)

Genbach Alexander A.

2016-01-01

Full Text Available Holography and high-speed filming were used to reveal movements and deformations of the capillary and porous material, allowing to calculate thermo-hydraulic characteristics of boiling liquid in the porous structures. These porous structures work at the joint action of capillary and mass forces, which are generalised in the form of dependences used in the calculation for oil coolers in thermal power plants (TPP. Furthermore, the mechanism of the boiling process in porous structures in the field of mass forces is explained. The development process of water steam formation in the mesh porous structures working at joint action of gravitational and capillary forces is investigated. Certain regularities pertained to the internal characteristics of boiling in cells of porous structure are revealed, by means of a holographic interferometry and high-speed filming. Formulas for calculation of specific thermal streams through thermo-hydraulic characteristics of water steam formation in mesh structures are obtained, in relation to heat engineering of thermal power plants. This is the first calculation of heat flow through the thermal-hydraulic characteristics of the boiling process in a reticulated porous structure obtained by a photo film and holographic observations.

Improvement of cooldown time of LSF9599 flexure-bearing SADA cooler

Science.gov (United States)

Mullié, Jeroen; vd Groep, Willem; Bruins, Peter; Benschop, Tonny; de Koning, Arjan; Dam, Jacques

2006-05-01

Thales Cryogenics has presented the LSF 9599 SADA II flexure cooler in 2005. Based on Thales' well-known moving magnet flexure technology, the LSF 9599 complies with the SADA II specification with respect to performance, envelope and mass. Being the first manufacturer offering a full flexure-bearing supported cooler that fits within the SADA II envelope, Thales Cryogenics has been selected in several new (military) programs with their LSF coolers. For many of these new programs, the cooldown time requirements are more stringent than in the past, whereas at the same time size, complexity and thus thermal mass of the infrared sensor tends to increase. In order to respond to the need created by the combination of these trends, Thales Cryogenics started a development program to optimize cryogenic performance of the LSF 9599 cooler. The main goal for the development program is to reduce the cooldown time, while maintaining the SADA II compatible interface, and maintaining the robustness and proven reliability of the cooler. Within these constraints, the regenerator was further optimized using among others the experience with mixed-gauze regenerators obtained from our pulse tube research. Using the mixed gauze approach, the heat storage capacity of the regenerator is adapted as a function of the temperature profile over the regenerator, thus giving the optimum balance between heat storage capacity and pressure drop. A novel way of constructing the regenerator further decreases shuttle heat losses and other thermal losses in the regenerator. This paper describes the first results of the trade-offs and gives an overview of impact on cooldown times and efficiency figures achieved after the regenerator and displacer optimization.

Reliability improvements on Thales RM2 rotary Stirling coolers: analysis and methodology

Science.gov (United States)

Cauquil, J. M.; Seguineau, C.; Martin, J.-Y.; Benschop, T.

2016-05-01

The cooled IR detectors are used in a wide range of applications. Most of the time, the cryocoolers are one of the components dimensioning the lifetime of the system. The cooler reliability is thus one of its most important parameters. This parameter has to increase to answer market needs. To do this, the data for identifying the weakest element determining cooler reliability has to be collected. Yet, data collection based on field are hardly usable due to lack of informations. A method for identifying the improvement in reliability has then to be set up which can be used even without field return. This paper will describe the method followed by Thales Cryogénie SAS to reach such a result. First, a database was built from extensive expertizes of RM2 failures occurring in accelerate ageing. Failure modes have then been identified and corrective actions achieved. Besides this, a hierarchical organization of the functions of the cooler has been done with regard to the potential increase of its efficiency. Specific changes have been introduced on the functions most likely to impact efficiency. The link between efficiency and reliability will be described in this paper. The work on the two axes - weak spots for cooler reliability and efficiency - permitted us to increase in a drastic way the MTTF of the RM2 cooler. Huge improvements in RM2 reliability are actually proven by both field return and reliability monitoring. These figures will be discussed in the paper.

Development and Evaluation of a Sandia Cooler-based Refrigerator Condenser

Energy Technology Data Exchange (ETDEWEB)

Johnson, Terry A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kariya, Harumichi Arthur [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Leick, Michael T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zimmerman, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Li, Manjie [Univ. of Maryland, College Park, MD (United States); Du, Yilin [Univ. of Maryland, College Park, MD (United States); Lee, Hoseong [Univ. of Maryland, College Park, MD (United States); Hwang, Yunho [Univ. of Maryland, College Park, MD (United States); Radermacher, Reinhard [Univ. of Maryland, College Park, MD (United States)

2015-07-01

This report describes the first design of a refrigerator condenser using the Sandia Cooler, i.e. air - bearing supported rotating heat - sink impeller. The project included ba seline performance testing of a residential refrigerator, analysis and design development of a Sandia Cooler condenser assembly including a spiral channel baseplate, and performance measurement and validation of this condenser system as incorporated into the residential refrigerator. Comparable performance was achieved in a 60% smaller volume package. The improved modeling parameters can now be used to guide more optimized designs and more accurately predict performance.

Market Assessment and Commercialization Strategy for the Radial Sandia Cooler

Energy Technology Data Exchange (ETDEWEB)

Goetzler, William [Navigant Consulting, Inc., Burlington, MA (United States); Shandross, Richard [Navigant Consulting, Inc., Burlington, MA (United States); Weintraub, Daniel [Navigant Consulting, Inc., Burlington, MA (United States); Young, Jim [Navigant Consulting, Inc., Burlington, MA (United States)

2014-02-01

This market assessment and commercialization report characterizes and assesses the market potential of the rotating heat exchanger technology developed at Sandia National Laboratories (SNL), known as the Radial Sandia Cooler. The RSC is a novel, motor-driven, rotating, finned heat exchanger technology. The RSC was evaluated for the residential, commercial, industrial, and transportation markets. Recommendations for commercialization were made based on assessments of the prototype RSC and the Sandia Cooler technology in general, as well as an in-depth analysis of the six most promising products for initial RSC commercialization.

Simulations of space charge neutralization in a magnetized electron cooler

Energy Technology Data Exchange (ETDEWEB)

Gerity, James [Texas A-M; McIntyre, Peter M. [Texas A-M; Bruhwiler, David Leslie [RadiaSoft, Boulder; Hall, Christopher [RadiaSoft, Boulder; Moens, Vince Jan [Ecole Polytechnique, Lausanne; Park, Chong Shik [Fermilab; Stancari, Giulio [Fermilab

2017-02-02

Magnetized electron cooling at relativistic energies and Ampere scale current is essential to achieve the proposed ion luminosities in a future electron-ion collider (EIC). Neutralization of the space charge in such a cooler can significantly increase the magnetized dynamic friction and, hence, the cooling rate. The Warp framework is being used to simulate magnetized electron beam dynamics during and after the build-up of neutralizing ions, via ionization of residual gas in the cooler. The design follows previous experiments at Fermilab as a verification case. We also discuss the relevance to EIC designs.

Thermoelectric cooler application in electronic cooling

International Nuclear Information System (INIS)

Chein Reiyu; Huang Guanming

2004-01-01

This study addresses thermoelectric cooler (TEC) applications in the electronic cooling. The cold side temperature (T c ) and temperature difference between TEC cold and hot sides (ΔT=T h -T c , T h =temperature of hot side of TEC) were used as the parameters. The cooling capacity, junction temperature, coefficient of performance (COP) of TEC and the required heat sink thermal resistance at the TEC hot side were computed. The results indicated that the cooling capacity could be increased as T c increased and ΔT was reduced. The maximum cooling capacity and chip junction temperature obtained were 207 W and 88 deg. C, respectively. The required heat sink thermal resistance on TEC hot side was 0.054 deg. C/W. Larger cooling capacity and higher COP could be obtained when the TEC was operated in the enforced regimes (ΔT c values and heat sink thermal resistance at the TEC hot side. A microchannel heat sink using water or air as the coolant was demonstrated to meet the low thermal heat sink resistance requirement for TEC operated at maximum cooling capacity conditions

Experimental characterization of the Hitrap Cooler trap with highly charged ions.

OpenAIRE

Fedotova, Svetlana

2013-01-01

The HITRAP (Highly charged Ions TRAP)facility is being set up and commissioned at GSI, Darmstadt. It will provide heavy, highly charged ions at low velocities to high-precision atomic physics experiments. Within this work the Cooler trap- the key element of the HITRAP facility was tested. The Cooler trap was assembled, aligned, and commissioned in trapping experiments with ions from off-line sources.The work performed within the scope of this thesis provided the baseline for further operation...

Comparative analysis of linear motor geometries for Stirling coolers

Science.gov (United States)

R, Rajesh V.; Kuzhiveli, Biju T.

2017-12-01

Compared to rotary motor driven Stirling coolers, linear motor coolers are characterized by small volume and long life, making them more suitable for space and military applications. The motor design and operational characteristics have a direct effect on the operation of the cooler. In this perspective, ample scope exists in understanding the behavioural description of linear motor systems. In the present work, the authors compare and analyze different moving magnet linear motor geometries to finalize the most favourable one for Stirling coolers. The required axial force in the linear motors is generated by the interaction of magnetic fields of a current carrying coil and that of a permanent magnet. The compact size, commercial availability of permanent magnets and low weight requirement of the system are quite a few constraints for the design. The finite element analysis performed using Maxwell software serves as the basic tool to analyze the magnet movement, flux distribution in the air gap and the magnetic saturation levels on the core. A number of material combinations are investigated for core before finalizing the design. The effect of varying the core geometry on the flux produced in the air gap is also analyzed. The electromagnetic analysis of the motor indicates that the permanent magnet height ought to be taken in such a way that it is under the influence of electromagnetic field of current carrying coil as well as the outer core in the balanced position. This is necessary so that sufficient amount of thrust force is developed by efficient utilisation of the air gap flux density. Also, the outer core ends need to be designed to facilitate enough room for the magnet movement under the operating conditions.

Thermoelectric Coolers with Sintered Silver Interconnects

Science.gov (United States)

Kähler, Julian; Stranz, Andrej; Waag, Andreas; Peiner, Erwin

2014-06-01

The fabrication and performance of a sintered Peltier cooler (SPC) based on bismuth telluride with sintered silver interconnects are described. Miniature SPC modules with a footprint of 20 mm2 were assembled using pick-and-place pressure-assisted silver sintering at low pressure (5.5 N/mm2) and moderate temperature (250°C to 270°C). A modified flip-chip bonder combined with screen/stencil printing for paste transfer was used for the pick-and-place process, enabling high positioning accuracy, easy handling of the tiny bismuth telluride pellets, and immediate visual process control. A specific contact resistance of (1.4 ± 0.1) × 10-5 Ω cm2 was found, which is in the range of values reported for high-temperature solder interconnects of bismuth telluride pellets. The realized SPCs were evaluated from room temperature to 300°C, considerably outperforming the operating temperature range of standard commercial Peltier coolers. Temperature cycling capability was investigated from 100°C to 235°C over more than 200 h, i.e., 850 cycles, during which no degradation of module resistance or cooling performance occurred.

The impact of fouling on performance evaluation of evaporative coolers and condensers

Energy Technology Data Exchange (ETDEWEB)

Qureshi, B.A.; Zubair, S.M. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia). Mechanical Engineering Dept.

2005-11-15

Fouling of evaporative cooler and condenser tubes is one of the most important factors affecting their thermal performance, which reduces effectiveness and heat transfer capability with time. In this paper, the experimental data on fouling reported in the literature are used to develop a fouling model for this class of heat exchangers. The model predicts the decrease in heat transfer rate with the growth of fouling. A detailed model of evaporative coolers and condensers, in conjunction with the fouling model, is used to study the effect of fouling on the thermal performance of these heat exchangers at different air inlet wet bulb temperatures. The results demonstrate that fouling of tubes reduces gains in performance resulting from decreasing values of air inlet wet bulb temperature. It is found that the maximum decrease in effectiveness due to fouling is about 55 and 78% for the evaporative coolers and condensers, respectively, investigated in this study. For the evaporative cooler, the value of process fluid outlet temperature T{sub p,out} varies by 0.66% only at the clean condition for the ambient wet bulb temperatures considered. (author)

Results from the Cooler and Lead Tests

International Nuclear Information System (INIS)

Green, Michael A.

2010-01-01

The report presents the results of testing MICE spectrometer magnet current leads on a test apparatus that combines both the copper leads and the high temperature superconducting (HTS) leads with a single Cryomech PT415 cooler and liquid helium tank. The current is carried through the copper leads from 300 K to the top of the HTS leads. The current is then carried through the HTS leads to a feed-through from the vacuum space to the inside of a liquid helium tank. The experiment allows one to measure the performance of both cooler stages along with the performance of the leads. While the leads were powered we measured the voltage drops through the copper leads, through the HTS leads, through spliced to the feed-through, through the feed-through and through the low-temperature superconducting loop that connects one lead to the other. Measurements were made using the leads that were used in spectrometer magnet 1A and spectrometer magnet 2A. These are the same leads that were used for Superbend and Venus magnets at LBNL. The IL/A for these leads was 5.2 x 10 6 m -1 . The leads turned out to be too long. The same measurements were made using the leads that were installed in magnet 2B. The magnet 2B leads had an IL/A of 3.3 x 10 6 A m -1 . This report discusses the cooler performance and the measured electrical performance of the lead circuit that contains the copper leads and the superconducting leads. All of the HTS leads that were installed in magnet 2B were current tested using this apparatus.

Thermoelectric cooler concepts and the limit for maximum cooling

International Nuclear Information System (INIS)

Seifert, W; Hinsche, N F; Pluschke, V

2014-01-01

The conventional analysis of a Peltier cooler approximates the material properties as independent of temperature using a constant properties model (CPM). Alternative concepts have been published by Bian and Shakouri (2006 Appl. Phys. Lett. 89 212101), Bian (et al 2007 Phys. Rev. B 75 245208) and Snyder et al (2012 Phys. Rev. B 86 045202). While Snyder's Thomson cooler concept results from a consideration of compatibility, the method of Bian et al focuses on the redistribution of heat. Thus, both approaches are based on different principles. In this paper we compare the new concepts to CPM and we reconsider the limit for maximum cooling. The results provide a new perspective on maximum cooling. (paper)

Experimental testing of a small sorption air cooler using composite material made from natural siliceous shale and chloride

International Nuclear Information System (INIS)

Liu, Hongzhi; Nagano, Katsunori; Morita, Atsushi; Togawa, Junya; Nakamura, Makoto

2015-01-01

A sorption air cooler experimental setup including a reactor and fin tube condenser/evaporator was built. The reactor was developed with inner copper fins and dual layers of curing copper meshes. Composite material made by impregnating LiCl into the mesopores of Wakkanai Siliceous Shale (WSS) micropowders was packed between the intervals of two fins. Heat transfer was enhanced by the attached fins, and the dual layers of curing meshes installed between each interval of two fins were designed to improve the sorbate mass transfer. On the other hand, the fin-tube evaporator/condenser with fins outside is valuable for improving the convective heat transfer between the functional water inside the evaporator/condenser and the flowing outside heat transfer medium, air. The sorption capacity of the composite material increased dramatically after being impregnated with LiCl. Among the four tested samples, WSS + 40 wt% LiCl exhibits the best performance. A regeneration temperature of 80 °C appears to be optimal for obtaining both a high COP and high specific cooling power. A lower condensation temperature can increase the cooling power. The sorption and desorption times of 60 min yield a reasonable compromise between cooling COP and mass specific cooling powers. The developed sorption air cooler system using WSS + 40 wt% LiCl can store heat at temperatures below 100 °C and produce cooling energy with a cooling coefficient of performance (COP) of approximately 0.3. - Highlights: • Mesoporous composite material was developed using natural siliceous shale and LiCl. • Properties of the developed material were measured. • A sorption air cooler experimental setup including an inner-fin reactor and a fin tube condenser/evaporator was built. • The performance of the composite material in the sorption air cooler was examined. • The sorption air cooler system can produce cooling energy with a cooling COP around 0.3

Improved cooler design of electric arc furnace refractory in mining industry using thermal analysis modeling and simulation

International Nuclear Information System (INIS)

Istadi, I.; Bindar, Y.

2014-01-01

Production of steel and nickel using the electric arc furnace should be focused on the intensification of energy. Improvement of energy efficiency of the most consuming facilities was achieved by improving the use of alternative energy minimization such as reducing the heat lost of hot gases, minimizing the heat radiated through refractory linings of metallurgical furnaces, and cooling the highly thermally stressed components. The refractory of electric arc furnace should be modified to achieve the best cooling system of the furnace. In this physical modeling and simulation works, four modification scenarios of wall refractory designs were simulated, i.e. refractory with basic design, refractory with deep plate coolers, refractory with extra plate coolers, and refractory with wall falling film coolers. Finally, the use of deep plate cooler and the existing waffle cooler system was considered to be the best design of efficient electric arc furnace operationally. - Highlights: • Electric arc furnace design should be focused on the intensification of energy. • Refractory of electric arc furnace were modified to achieve the best cooling system. • Four modification scenarios of the wall refractory designs were simulated. • Use of deep plate cooler and existing waffle cooler system is the best cooling

Fan Cooler Operation in Kori 1 for Mitigating Severe Accident

International Nuclear Information System (INIS)

Suh, Nam Duk; Park, Jae Hong

2005-01-01

The Korea Ministry of Science and Technology (MOST) issued the 'Policy on Severe Accident of Nuclear Power Plants' in August 2001. According to the policy it was required for the licensee to develop a plant specific severe accident management guideline (SAMG) and to implement it. Thus the utility has made an implementation plan to develop SAMGs for operating plants. The SAMG for Kori unit 1 was submitted to the government on January 2004. Since then, the government trusted KINS to review the submitted SAMG in view of its feasibility and effectiveness. The first principle of the developed SAMG is to use only the available facilities as it is without introducing any system change. Because Kori-1 has no mitigative facility against combustible gases during severe accident, it relies heavily both on spray and on fan cooler systems to control the containment condition. Thus one of the issues raised during the review is to know whether the fan coolers which are designed for DBA LOCA can be effective in mitigating the severe accident conditions. This paper presents an analysis result of fan cooler operation in controlling the containment condition during severe accident of Kori 1

Feasibility of a solar-assisted winter air-conditioning system using evaporative air-coolers

Energy Technology Data Exchange (ETDEWEB)

El-Awad, Mohamed M. [Mechanical Engineering Department, the University of Khartoum, P.O. Box 321 Khartoum (Sudan)

2011-07-01

The paper presents a winter air-conditioning system which is suitable for regions with mildly cold but dry winters. The system modifies the evaporative air-cooler that is commonly used for summer air-conditioning in such regions by adding a heating process after the humidification process. The paper describes a theoretical model that is used to estimate the system's water and energy consumption. It is shown that a 150-LPD solar heater is adequate for air-conditioning a 500 ft3/min (14.4 m3/min) air flow rate for four hours of operation. The maximum air-flow rate that can be heated by a single solar water-heater for four hours of operation is about 900-cfm, unless a solar water heater large than a 250-LPD heater is used. For the 500 ft3/min air flow rate the paper shows that the 150, 200, 250 and 300 LPD solar water-heaters can provide air-conditioning for 4, 6, 8 and 10 hours, respectively, while consuming less energy than the equivalent refrigerated-type air-conditioner.

An implantable nerve cooler for the exercising dog.

Science.gov (United States)

Borgdorff, P; Versteeg, P G

1984-01-01

An implantable nerve cooler has been constructed to block cervical vago-sympathetic activity in the exercising dog reversibly. An insulated gilt brass container implanted around the nerve is perfused with cooled alcohol via silicone tubes. The flow of alcohol is controlled by an electromagnetic valve to keep nerve temperature at the required value. Nerve temperature is measured by a thermistor attached to the housing and in contact with the nerve. It is shown that, during cooling, temperature at this location differs less than 2 degrees C from nerve core temperature. Measurement of changes in heart rate revealed that complete vagal block in the conscious animal is obtained at a nerve temperature of 2 degrees C and can be achieved within 50 s. During steady-state cooling in the exercising animal nerve temperature varied less than 0.5 degree C. When the coolers after 2 weeks of implantation were removed they showed no oxydation and could be used again.

Influence of the outlet air temperature on the thermohydraulic behaviour of air coolers

Directory of Open Access Journals (Sweden)

Đorđević Emila M.

2003-01-01

Full Text Available The determination of the optimal process conditions for the operation of air coolers demands a detailed analysis of their thermohydraulic behaviour on the one hand, and the estimation of the operating costs, on the other. One of the main parameters of the thermohydraulic behaviour of this type of equipment, is the outlet air temperature. The influence of the outlet air temperature on the performance of air coolers (heat transfer coefficient overall heat transfer coefficient, required surface area for heat transfer air-side pressure drop, fan power consumption and sound pressure level was investigated in this study. All the computations, using AirCooler software [1], were applied to cooling of the process fluid and the condensation of a multicomponent vapour mixture on two industrial devices of known geometries.

Numerical study on interaction of local air cooler with stratified hydrogen cloud in a large vessel

Energy Technology Data Exchange (ETDEWEB)

Liang, Z. [Atomic Energy of Canada Limited, Chalk River Laboratories, ON K0J 1J0 (Canada); Andreani, M. [Laboratory for Thermal-Hydraulics, Paul Scherrer Institut, 5232 Villigen (Switzerland)

2012-07-01

Within the framework of the ERCOSAM project, planning calculations are performed to examine sensitivity parameters that can affect the break-up (erosion) of a helium layer by mitigation devices (i.e., cooler, spray, or Passive Autocatalytic Recombiner - PAR). This paper reports the GOTHIC analysis results for the cooler tests to be performed in the PANDA facility. The cooler elevation and geometry, helium layer thickness, steam distribution in the vessel, and the vessel geometry (inter-connected multi-compartments versus a single volume) on the erosion process as well as the cooling capacity are studied. This analysis is valuable because only a limited number of conditions will be examined in the planned experiments. The study provides a useful understanding of the interaction of a cooler with a stratified atmosphere. (authors)

Experimental study of a high intensity radio-frequency cooler

Directory of Open Access Journals (Sweden)

Ramzi Boussaid

2015-07-01

Full Text Available Within the framework of the DESIR/SPIRAL-2 project, a radio-frequency quadrupole cooler named SHIRaC has been studied. SHIRaC is a key device of SPIRAL-2, designed to enhance the beam quality required by DESIR. The preliminary study and development of this device has been carried out at Laboratoire de Physique Corpusculaire de CAEN (LPC Caen, France. The goal of this paper is to present the experimental studies conducted on a SHIRaC prototype. The main peculiarity of this cooler is its efficient handling and cooling of ion beams with currents going up as high as 1  μA which has never before been achieved in any of the previous coolers. Much effort has been made lately into these studies for development of appropriate optics, vacuum and rf systems which allow cooling of beams of large emittance (∼80π  mm mrad and high current. The dependencies of SHIRaC’s transmission and the cooled beam parameters in terms of geometrical transverse emittance and the longitudinal energy spread have also been discussed. Investigation of beam purity at optimum cooling condition has also been done. Results from the experiments indicate that an emittance reduction of less than 2.5π  mm mrad and a longitudinal energy spread reduction of less than 4 eV are obtained with more than 70% of ion transmission. The emittance is at expected values whereas the energy spread is not.

Six Sigma methods applied to cryogenic coolers assembly line

Science.gov (United States)

Ventre, Jean-Marc; Germain-Lacour, Michel; Martin, Jean-Yves; Cauquil, Jean-Marc; Benschop, Tonny; Griot, René

2009-05-01

Six Sigma method have been applied to manufacturing process of a rotary Stirling cooler: RM2. Name of the project is NoVa as main goal of the Six Sigma approach is to reduce variability (No Variability). Project has been based on the DMAIC guideline following five stages: Define, Measure, Analyse, Improve, Control. Objective has been set on the rate of coolers succeeding performance at first attempt with a goal value of 95%. A team has been gathered involving people and skills acting on the RM2 manufacturing line. Measurement System Analysis (MSA) has been applied to test bench and results after R&R gage show that measurement is one of the root cause for variability in RM2 process. Two more root causes have been identified by the team after process mapping analysis: regenerator filling factor and cleaning procedure. Causes for measurement variability have been identified and eradicated as shown by new results from R&R gage. Experimental results show that regenerator filling factor impacts process variability and affects yield. Improved process haven been set after new calibration process for test bench, new filling procedure for regenerator and an additional cleaning stage have been implemented. The objective for 95% coolers succeeding performance test at first attempt has been reached and kept for a significant period. RM2 manufacturing process is now managed according to Statistical Process Control based on control charts. Improvement in process capability have enabled introduction of sample testing procedure before delivery.

Condensing and water supplying systems in an atomic power plant

International Nuclear Information System (INIS)

Shinmura, Akira.

1975-01-01

Object: To reduce heat loss and eliminate accumulation of drain in water supplying and heating units in an atomic power plant by providing a direct contact type drain cooler between a gland-exhauster vapor condenser and a condensing and de-salting means, the drain from each water supplying and heating unit being collected in said cooler for heating the condensed water. Structure: Condensed water from a condenser is fed by a low pressure condensing pump through an air ejector and gland-exhauster vapor condenser to the direct-contact type drain cooler and is condensed in each water supply heater. Next, it is heated by drain fed through a drain level adjuster valve and an orifice and then forced by a medium pressure condenser pump into the condensing and de-salting means. It is then supplied by a high pressure condensing pump into the successive water supply heater. (Kamimura, M.)

Report on the status of linear drive coolers for the Department of Defense Standard Advanced Dewar Assembly (SADA)

Science.gov (United States)

Salazar, William

2003-01-01

The Standard Advanced Dewar Assembly (SADA) is the critical module in the Department of Defense (DoD) standardization effort of scanning second-generation thermal imaging systems. DoD has established a family of SADA's to address requirements for high performance (SADA I), mid-to-high performance (SADA II), and compact class (SADA III) systems. SADA's consist of the Infrared Focal Plane Array (IRFPA), Dewar, Command and Control Electronics (C&CE), and the cryogenic cooler. SADA's are used in weapons systems such as Comanche and Apache helicopters, the M1 Abrams Tank, the M2 Bradley Fighting Vehicle, the Line of Sight Antitank (LOSAT) system, the Improved Target Acquisition System (ITAS), and Javelin's Command Launch Unit (CLU). DOD has defined a family of tactical linear drive coolers in support of the family of SADA's. The Stirling linear drive cryo-coolers are utilized to cool the SADA's Infrared Focal Plane Arrays (IRFPAs) to their operating cryogenic temperatures. These linear drive coolers are required to meet strict cool-down time requirements along with lower vibration output, lower audible noise, and higher reliability than currently fielded rotary coolers. This paper will (1) outline the characteristics of each cooler, (2) present the status and results of qualification tests, and (3) present the status and test results of efforts to increase linear drive cooler reliability.

Method for thermoelectric cooler utilization using manufacturer's technical information

Science.gov (United States)

Ajiwiguna, Tri Ayodha; Nugroho, Rio; Ismardi, Abrar

2018-03-01

Thermoelectric cooler (TEC) module has been widely used for many applications. In this study, a procedure to use TEC module for specific requirement is developed based on manufacturer's technical data. For study case, the cooling system using TEC module is designed and tested to maintain 6.6 liter of water at 24 °C while surrounding temperature is 26 °C. First, cooling load estimation is performed empirically by observing the temperature change when cold water is inside the container. Second, the working temperature on hot side and cold side of TEC are determined. Third, the parameters of Seebeck coefficient, thermal resistance and electrical resistance are predicted by using information from the manufacturer. Fourth, the operating current is determined by the assumption the voltage across the TEC is 12V. Fifth, cooling capacity of TEC module is calculated by using energy balance equation of TEC. Sixth, the cooling load and cooling capacity are compared to determine the number of TEC module needed. The result of these calculations showed that one TEC module is enough for cooling system since the cooling load is 17.5 W while the cooling capacity is 18.87 W. From the experimental result, the set point temperature was achieved using one TEC module as predicted in calculations steps.

Status of the cooler synchrotron COSY Juelich. Papers

International Nuclear Information System (INIS)

1994-09-01

The eight papers present the status of COSY, operational characteristics of the COSY electron cooler, a broad-band multiple-harmonic acceleration structure, diagnostic tools, a stochastic cooling system, a narrow-band digital RF-noise generator, an RF-synthesizer, and a longitudinal phase space tracking of particles in a multiple harmonic RF-system. (DG)

Qualification campaign of the 50 mK hybrid sorption-ADR cooler for SPICA/SAFARI

Science.gov (United States)

Duval, J.-M.; Duband, L.; Attard, A.

2015-12-01

SAFARI (SpicA FAR-infrared Instrument) is an infrared instrument planned to be part of the SPICA (SPace Infrared telescope for Cosmology and Astrophysics) Satellite. It will offer high spectral resolution in the 30 - 210 μm frequency range. SAFARI will benefit from the cold telescope of SPICA and to obtain the required detectors sensitivity, a temperature of 50 mK is required. This temperature is reached thanks to the use of a hybrid sorption - ADR (Adiabatic Demagnetization Refrigerator) cooler presented here. This cooler provides respectively 14 μW and 0.4 μW of cooling power at 300 mK and 50 mK. The cooler is planned to advantageously use two thermal interfaces of the instrument at 1.8 and 4.9 K. One of the challenges discussed in this paper is the low power available at each intercept. A dedicated laboratory electronic is being designed based on previous development with a particular focus on the 50 mK readout. Temperature regulation at 50 mK is also discussed. This cooler has been designed following flight constraints and will reach a high TRL, including mechanical and environmental tests at the end of the on-going qualification campaign.

A study on the effects of system pressure on heat and mass transfer rates of an air cooler

International Nuclear Information System (INIS)

Jung, Hyung Ho

2002-01-01

In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements

Effect of operating conditions on performance of silica gel-water air-fluidised desiccant cooler

Directory of Open Access Journals (Sweden)

Rogala Zbigniew

2017-01-01

Full Text Available Fluidised desiccant cooling is reported in the literature as an efficient way to provide cooling for air-conditioning purposes. The performance of this technology can be described by electric and thermal Coefficients of Performance (COP and Specific Cooling Power (SCP. In this paper comprehensive theoretical study was carried out in order to assess the effect of operating conditions such as: superficial air velocity, desiccant particle diameter, bed switching time and desiccant filling height on the performance of fluidised desiccant cooler (FDC. It was concluded that FDC should be filled with as small as possible desiccant particles featuring diameters and should not be operated with shorter switching times than optimum. Moreover in order to efficiently run such systems superficial air velocities during adsorption and desorption should be similar. At last substantial effect of desiccant filling height on performance of FDC was presented.

NASA Lewis Stirling SPRE testing and analysis with reduced number of cooler tubes

International Nuclear Information System (INIS)

Wong, W.A.; Cairelli, J.E.; Swec, D.M.; Doeberling, T.J.; Lakatos, T.F.; Madi, F.J.

1994-01-01

Free-piston Stirling power converters are a candidate for high capacity space power applications. The Space Power Research Engine (SPRE), a free-piston Stirling engine coupled with a linear alternator, is being tested at the NASA Lewis Research Center in support of the Civil Space Technology Initiative. The SPRE is used as a test bed for evaluating converter modifications which have the potential to improve converter performance and for validating computer code predictions. Reducing the number of cooler tubes on the SPRE has been identified as a modification with the potential to significantly improve power and efficiency. This paper describes experimental tests designed to investigate the effects of reducing the number of cooler tubes on converter power, efficiency and dynamics. Presented are test results from the converter operating with a reduced number of cooler tubes and comparisons between this data and both baseline test data and computer code predictions

How the Performance of a Superconducting Magnet is affected by the Connection between a small cooler and the Magnet

International Nuclear Information System (INIS)

Green, Michael A.

2005-01-01

As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the magnet cold during a loss of cooling, and (3) constraints on the distance from the cooler cold heads and the magnet and its shield. Two methods for connecting low temperature coolers to superconducting magnets have been studied. The first method uses a cold strap to connect the cold heads directly to the loads. This method is commonly used for cryogen-free magnets. The second method uses a thermal siphon and liquid cryogens to make the connection between the load being cooled and the cold head. The two methods of transferring heat from the magnet to the cooler low temperature cold head are compared for the two temperature ranges given above

Performance of the natural cooler to keep the freshness of vegetables and fruits in Medan City

Science.gov (United States)

Sitorus, T. B.; Ambarita, H.; Ariani, F.; Sitepu, T.

2018-02-01

One application in a direct evaporative cooling system was a natural cooler. The advantages of this system were not using the electrical energy and so far also environmentally. This research aims to obtain a performance analysis of the natural cooler as a store for vegetables and fruits in Medan city. The materials for natural cooler consists of teak wood and gunny. This study makes experiments during seven days in the open air. The parameter measurement on the weather was using HOBO devices and to record the temperature changes for vegetables or even fruits is using its acquisition data. The results showed that the maximum efficiency of the natural cooler could be obtained for 43.79% in the average air temperature of 30.51°C, the air humidity average is 85.12% with average solar radiation of 183.98 W/m2. Experimental data were showing that the condition of freshness on vegetables or even on fruits was heavily influenced by weather conditions.

NUMERICAL STUDIES OF THE FRICTION FORCE FOR THE RHIC ELECTRON COOLER

International Nuclear Information System (INIS)

FEDOTOV, A.V.; BEN-ZVI, I.; LITVINENKO, V.

2005-01-01

Accurate calculation of electron cooling times requires an accurate description of the dynamical friction force. The proposed RHIC cooler will require ∼55 MeV electrons, which must be obtained from an RF linac, leading to very high transverse electron temperatures. A strong solenoid will be used to magnetize the electrons and suppress the transverse temperature, but the achievable magnetized cooling logarithm will not be large. In this paper, we explore the magnetized friction force for parameters of the RHIC cooler, using the VORPAL code [l]. VORPAL can simulate dynamical friction and diffusion coefficients directly from first principles [2]. Various aspects of the fiction force are addressed for the problem of high-energy electron cooling in the RHIC regime

RFQ Cooler and Buncher (and beam line section associated)

CERN Document Server

Podadera-Aliseda, I

2003-01-01

Developing a new RFQ cooler and buncher for ISOLDE. Such a device combines an energy loss in buffer gas atom-ion collisions with confinement provided by RF-field in transverse plane. Optional confinement in longitudinal direction is provided by static potential dwell. Then, an improvement of the beam line is achieved for all the experiments at ISOLDE. The RFQ operates inside a high voltage cage of 60 kV, and with a system of turbomulecular pumps both to keep the high vacuum before/after the RFQ and to keep a low pressure (around 0,1 mbar) inside the RFQ. The project is to be thought not only as a mechanical design and construction project, unless as a project of research and development, since it is about improving (operationally and technically) the existing RFQ cooler and buncher placed around the world. Due to ion optical reasons whole beam line section has to be redesigned and constructed as a part of this project.

Qualification campaign of the 50 mK hybrid sorption-ADR cooler for SPICA/SAFARI

International Nuclear Information System (INIS)

Duval, J-M; Duband, L; Attard, A

2015-01-01

SAFARI (SpicA FAR-infrared Instrument) is an infrared instrument planned to be part of the SPICA (SPace Infrared telescope for Cosmology and Astrophysics) Satellite. It will offer high spectral resolution in the 30 - 210 μm frequency range. SAFARI will benefit from the cold telescope of SPICA and to obtain the required detectors sensitivity, a temperature of 50 mK is required. This temperature is reached thanks to the use of a hybrid sorption - ADR (Adiabatic Demagnetization Refrigerator) cooler presented here. This cooler provides respectively 14 μW and 0.4 μW of cooling power at 300 mK and 50 mK. The cooler is planned to advantageously use two thermal interfaces of the instrument at 1.8 and 4.9 K. One of the challenges discussed in this paper is the low power available at each intercept. A dedicated laboratory electronic is being designed based on previous development with a particular focus on the 50 mK readout. Temperature regulation at 50 mK is also discussed. This cooler has been designed following flight constraints and will reach a high TRL, including mechanical and environmental tests at the end of the on-going qualification campaign. (paper)

First turn simulations in the cooler synchrotron COSY

International Nuclear Information System (INIS)

Dinev, D.

1991-07-01

This paper is devoted to the first turn correction and related problems in particle accelerators of synchrotron type. The paper consists of two parts. The first part is a survey of the existing methods for first turn steering. The second part is entirely devoted to the first turn in the cooler synchrotron COSY which is under assembling in KFA-Julich, Germany. (orig.)

Thermodynamic comparison of Peltier, Stirling, and vapor compression portable coolers

International Nuclear Information System (INIS)

Hermes, Christian J.L.; Barbosa, Jader R.

2012-01-01

Highlights: ► A Peltier, a Stirling, and two vapor compression refrigerators were compared. ► Tests were carried out to obtain key performance parameters of the systems. ► The overall 2nd-law efficiency was splited to take into account the internal and external irreversibilities. ► The Stirling and vapor compression refrigeration systems presented higher efficiencies. ► The thermoelectric device was not at the same efficiency level as the other coolers. -- Abstract: The present study compares the thermodynamic performance of four small-capacity portable coolers that employ different cooling technologies: thermoelectric, Stirling, and vapor compression using two different compressors (reciprocating and linear). The refrigeration systems were experimentally evaluated in a climatized chamber with controlled temperature and humidity. Tests were carried out at two different ambient temperatures (21 and 32 °C) in order to obtain key performance parameters of the systems (e.g., power consumption, cooling capacity, internal air temperature, and the hot end and cold end temperatures). These performance parameters were compared using a thermodynamic approach that splits the overall 2nd law efficiency into two terms, namely, the internal and external efficiencies. In doing so, the internal irreversibilities (e.g., friction in the working fluid in the Stirling and vapor compression machines, Joule heating and heat conduction in the thermoelectric devices of the Peltier cooler) were separated from the heat exchanger losses (external irreversibilities), allowing the comparison between different refrigeration technologies with respect to the same thermodynamic baseline.

Production induced boiling and cold water entry in the Cerro Prieto geothermal reservoir indicated by chemical and physical measurements

Energy Technology Data Exchange (ETDEWEB)

Grant, M.A. (DSIR, Wellington, New Zealand); Truesdell, A.H.; Manon, A.

1981-01-01

Chemical and physical data suggest that the relatively shallow western part of the Cerro Prieto reservoir is bounded below by low permeability rocks, and above and at the sides by an interface with cooler water. There is no continuous permeability barrier around or immediately above the reservoir. Permeability within the reservoir is dominantly intergranular. Mixture with cooler water rather than boiling is the dominant cooling process in the natural state, and production causes displacement of hot water by cooler water, not by vapor. Local boiling occurs near most wells in response to pressure decreases, but no general vapor zone has formed.

Numerical study on transverse asymmetry in the temperature profile of a regenerator in a pulse tube cooler

DEFF Research Database (Denmark)

Andersen, Stig Kildegård; Dietrich, M.; Carlsen, Henrik

2007-01-01

Transverse asymmetry in the temperature profile of the regenerator in a Stirling-type pulse tube cooler as observed in experiments was analysed in a numerical study. The asymmetry was reproduced using a one-dimensional model of the cooler where the regenerator was modelled using two identical...

Calculation of forces on reactor containment fan cooler piping

International Nuclear Information System (INIS)

Miller, J.S.; Ramsden, K.

2004-01-01

The purpose of this paper is to present the results of the Reactor Containment Fan Cooler (RCFC) system piping load calculations. These calculations are based on piping loads calculated using the EPRI methodology and RELAP5 to simulate the hydraulic behavior of the system. The RELAP5 generated loads were compared to loads calculated using the EPRI GL-96-06 methodology. This evaluation was based on a pressurized water reactor's RCFC coils thermal hydraulic behavior during a Loss of Offsite Power (LOOP) and a loss of coolant accident (LOCA). The RCFC consist of two banks of service water and chill water coils. There are 5 SX and 5 chill water coils per bank. Therefore, there are 4 RCFC units in the containment with 2 banks of coils per RCFC. Two Service water pumps provide coolant for the 4 RCFC units (8 banks total, 2 banks per RCFC unit and 2 RCFC units per pump). Following a LOOP/LOCA condition, the RCFC fans would coast down and upon being re-energized, would shift to low-speed operation. The fan coast down is anticipated to occur very rapidly due to the closure of the exhaust damper as a result of LOCA pressurization effects. The service water flow would also coast down and be restarted in approximately 43 seconds after the initiation of the event. The service water would drain from the RCFC coils during the pump shutdown and once the pumps restart, water is quickly forced into the RCFC coils causing hydraulic loading on the piping. Because of this scenario and the potential for over stressing the piping, an evaluation was performed by the utility using RELAP5 to assess the piping loads. Subsequent to the hydraulic loads being analyzed using RELAP5, EPRI through GL-96-06 provided another methodology to assess loads on the RCFC piping system. This paper presents the results of using the EPRI methodology and RELAP5 to perform thermal hydraulic load calculations. It is shown that both EPRI methodology and RELAP5 calculations can be used to generate hydraulic loads

Optimization of multiple-module thermoelectric coolers using artificial-intelligence techniques

Energy Technology Data Exchange (ETDEWEB)

Chen, K. [University of Utah (United States). Dept. of Mechanical Engineering; Lin, G.T. [National Taiwan University of Science and Technology, Taipei (China). Dept. of Mechanical Engineering

2002-07-01

Genetic algorithm (GA) and simulated annealing (SA) methods were employed to optimize the current distribution of a cooler made up of a large number of thermoelectric (TE) modules. The TE modules were grouped into several clusters in the flow direction, and the electric currents supplied to different clusters were adjusted separately to achieve maximum energy efficiency or minimum refrigeration temperature for different,operating conditions and cooling requirements. Optimization results based on the design parameters of a large TE cooler showed considerable improvements in energy efficiency and refrigeration temperature when compared to the results of uniform current for the parallel-flow arrangement. On the other hand, results of the counter-flow arrangement showed only slight differences between uniform- and non-uniform-current optimizations. The optimization results of GA and SA were very close to each other. SA converged faster and was more computationally economical than GA for TE system optimization. (author)

Beam-plasma interaction in a synchrotron-cooler ring

International Nuclear Information System (INIS)

Itahashi, T.

1989-01-01

We propose a plasma target installed in the synchrotron-cooler ring in order to study the beam-plasma interaction. Various types of beam diagnostic devices and precise techniques developed for stochastic cooling and rf-stacking in the storage ring would be a powerful tool to approach the problems concerning the plasma behavior induced by the beam, such as plasma lens effect, anomalous stopping power and plasma instability. (author)

RFQ beam cooler and buncher for collinear laser spectroscopy of rare isotopes

Science.gov (United States)

Barquest, B. R.; Bollen, G.; Mantica, P. F.; Minamisono, K.; Ringle, R.; Schwarz, S.; Sumithrarachchi, C. S.

2017-09-01

A radiofrequency quadrupole (RFQ) ion beam cooler and buncher has been developed to deliver bunched beams with low transverse emittance, energy spread, and time spread to the BECOLA collinear laser spectroscopy system at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The beam cooler and buncher contains new features which enhance performance, especially for high count rate beams, as well as simplifying construction, maintenance, and operation. The transverse emittance, energy spread, and time spread of the bunched beam, as well as buncher efficiency are reported, showcasing the capabilities of the BECOLA facility to perform collinear laser spectroscopy measurements with bunched rare isotope beams at NSCL and at the future Facility for Rare Isotope Beams (FRIB).

Improving the Efficiency of the Heat Pump Control System of Carbon Dioxide Heat Pump with Several Evaporators and Gas Coolers

Directory of Open Access Journals (Sweden)

Sit M.L.

2016-12-01

Full Text Available The problem of coordination of the values of the refrigerant flow through the evaporators and gas coolers of the heat pump for the simultaneous production of heat and cold is studied. The compensation of the variations of the total flow through the evaporators is implemented using the variation of the capacity of the compressor and a corresponding change in flow through the auxiliary gas cooler of the heat pump. Control system of this gas cooler is constructed using the invariance principle of the output value (outlet temperature of the heated agent with respect to perturbations on the control channel (the refrigerant flow through the gas cooler. Principle of dual-channel compensation of the disturbance and advancing signal on input of control valve of the refrigerant through the gas cooler is ensured. Due to proposed solution, the intensity of the disturbances on the flow of refrigerant is reduced. Due to proposed technical solution power consumed by the heat pump compressor drive under transients is decreased.

Comparison of desiccant air conditioning systems with different indirect evaporative air coolers

International Nuclear Information System (INIS)

Pandelidis, Demis; Anisimov, Sergey; Worek, William M.; Drąg, Paweł

2016-01-01

Highlights: • A numerical study of desiccant air conditioning systems is presented. • The ε-NTU model is used for the analysis. • Different arrangements of the desiccant systems were compared. • The systems were compared under different operating conditions. - Abstract: This paper presents a numerical analysis of three desiccant air-conditioning systems equipped with different indirect evaporative air coolers: (1) the cross-flow Maisotsenko cycle heat and mass exchanger (HMX), (2) the regenerative counter-flow Maisotsenko cycle heat and mass exchanger and (3) the standard cross-flow evaporative air cooler. To analyze the desiccant wheel and the indirect evaporative air coolers, the modified ε-NTU-model was used. The simulations were performed under assumption that the desiccant wheel is regenerated with air heated to relatively low temperature values (50–60 °C), which can be produced with solar panels in typical moderate climatic conditions. It was established that the main advantage of the presented solutions is that they can provide comfort conditions even with less effective dehumidification. The different systems were compared under variable selected operational factors (i.e. inlet air temperature, humidity and regeneration air temperature). The analysis allowed establishing the advantages and disadvantages of presented solutions and allowed estimating their application potential.

Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

Energy Technology Data Exchange (ETDEWEB)

Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-07-28

Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO₂) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO₂ Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO₂ Brayton cycle is that it enables dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately

Implementation of a new blood cooler insert and tracking technology with educational initiatives and its effect on reducing red blood cell wastage.

Science.gov (United States)

Fadeyi, Emmanuel A; Emery, Wanda; Simmons, Julie H; Jones, Mary Rose; Pomper, Gregory J

2017-10-01

The objective was to report a successful implementation of a blood cooler insert and tracking technology with educational initiatives and its effect on reducing red blood cell (RBC) wastage. The blood bank database was used to quantify and categorize total RBC units issued in blood coolers from January 2010 to December 2015 with and without the new inserts throughout the hospital. Radiofrequency identification tags were used with special software to monitor blood cooler tracking. An educational policy on how to handle the coolers was initiated. Data were gathered from the software that provided a real-time location monitoring of the blood coolers with inserts throughout the institution. The implementation of the blood cooler with inserts and tracking device reduced mean yearly RBC wastage by fourfold from 0.64% to 0.17% between 2010 and 2015. The conserved RBCs corresponded to a total cost savings of $167,844 during the 3-year postimplementation period. The implementation of new blood cooler inserts, tracking system, and educational initiatives substantially reduced the mean annual total RBC wastage. The cost to implement this initiative may be small if there is an existing institutional infrastructure to monitor and track hospital equipment into which the blood bank intervention can be adapted when compared to the cost of blood wastage. © 2017 AABB.

Comparison of Test Stand and Helicopter Oil Cooler Bearing Condition Indicators

Science.gov (United States)

Dempsey, Paula J.; Branning, Jeremy; Wade, Damiel R.; Bolander, Nathan

2010-01-01

The focus of this paper was to compare the performance of HUMS condition indicators (CI) when detecting a bearing fault in a test stand or on a helicopter. This study compared data from two sources: first, CI data collected from accelerometers installed on two UH-60 Black Hawk helicopters when oil cooler bearing faults occurred, along with data from helicopters with no bearing faults; and second, CI data that was collected from ten cooler bearings, healthy and faulted, that were removed from fielded helicopters and installed in a test stand. A method using Receiver Operating Characteristic (ROC) curves to compare CI performance was demonstrated. Results indicated the bearing energy CI responded differently for the helicopter and the test stand. Future research is required if test stand data is to be used validate condition indicator performance on a helicopter.

Metal foams as gas coolers for exhaust gas recirculation systems subjected to particulate fouling

International Nuclear Information System (INIS)

Hooman, K.; Malayeri, M.R.

2016-01-01

Highlights: • Fouling of metal foam heat exchangers as EGR gas coolers is tested. • An optimal design was inferred based on the generated data. • A simple cleaning technique was suggested and evaluated. - Abstract: This paper presents experimental results indicating the benefits and challenges associated with the use of metal foams as Exhaust Gas Recirculation (EGR) coolers. Fouling of such heat exchangers is a critical issue and, as such, special attention has been paid to address this very issue in the present study where a soot generator has been employed to simulate the engine running condition. Effects of aluminium foam PPI and height as well as gas velocity are investigated. It has been noted that proper design of the foam can lead to significantly higher heat transfer rate and reasonable pressure drop compared to no-foam cases. More interestingly, it is demonstrated that the foams can be cleaned easily without relying on expensive cleaning techniques. Using simple brush-cleaning, the foams can be reused as EGR gas coolers with a performance penalty of only 17% (compared to a new or clean foam).

Solar-Powered Cooler and Heater for an Automobile Interior

Science.gov (United States)

Howard, Richard T.

2006-01-01

The apparatus would include a solar photovoltaic panel mounted on the roof and a panellike assembly mounted in a window opening. The window-mounted assembly would include a stack of thermoelectric devices sandwiched between two heat sinks. A fan would circulate interior air over one heat sink. Another fan would circulate exterior air over the other heat sink. The fans and the thermoelectric devices would be powered by the solar photovoltaic panel. By means of a double-pole, double-throw switch, the panel voltage fed to the thermoelectric stack would be set to the desired polarity: For cooling operation, the chosen polarity would be one in which the thermoelectric devices transport heat from the inside heat sink to the outside one; for heating operation, the opposite polarity would be chosen. Because thermoelectric devices are more efficient in heating than in cooling, this apparatus would be more effective as a heater than as a cooler. However, if the apparatus were to include means to circulate air between the outside and the inside without opening the windows, then its effectiveness as a cooler in a hot, sunny location would be increased.

Numerical simulation of a semi-indirect evaporative cooler

Energy Technology Data Exchange (ETDEWEB)

Martin, R. Herrero [Departamento de Ingenieria Termica y de Fluidos, Universidad Politecnica de Cartagena, C/Dr. Fleming, s/n (Campus Muralla), 30202 Cartagena, Murcia (Spain)

2009-11-15

This paper presents the experimental study and numerical simulation of a semi-indirect evaporative cooler (SIEC), which acts as an energy recovery device in air conditioning systems. The numerical simulation was conducted by applying the CFD software FLUENT implementing a UDF to model evaporation/condensation. The numerical model was validated by comparing the simulation results with experimental data. Experimental data and numerical results agree for the lower relative humidity series but not for higher relative humidity values. (author)

Electron gun design for HIRFL-CSR electron cooler

International Nuclear Information System (INIS)

Rao Yinong; Xia Jiawen; Yuan Youjin; Wei Baowen

1996-01-01

Adiabatic acceleration is employed to design the electron gun of HIRFL-CSR e-cooler by using the modified EGUN code. The electron beam transverse temperature variations with anode region and acceleration tube design parameters as well as the uniform solenoidal magnetic field are presented. Transversal temperature of less than 0.1 eV at a maximum current density of 0.244 A/cm 2 are obtained over the full energy range of 2.75∼165 keV

Surface tension confined liquid cryogen cooler

International Nuclear Information System (INIS)

Castles, S.H.; Schein, M.E.

1989-01-01

A cryogenic cooler is described for use in craft such as launch, orbital and space vehicles subject to changes in orientation and conditions of vibration and weightlessness comprising: an insulated tank; a porous open celled sponge-like material disposed substantially throughout the contained volume of the insulated tank; a cryogenic fluid disposed within the sponge-like material; a cooling finger immersed in the cryogenic fluid, the finger extending from inside the insulated tank externally to an outside source such as an instrument detector for the purpose of transmitting heat from the outside source into the cryogenic fluid; means for filling the insulated tank with cryogenic fluid; and means for venting vaporized cryogenic fluid from the insulated tank

Numerical Studies of the Friction Force for the RHIC Electron Cooler

CERN Document Server

Fedotov, Alexei V; Ben-Zvi, Ilan; Bruhwiler, David L; Busby, Richard; Litvinenko, Vladimir N; Schoessow, Paul

2005-01-01

Accurate calculation of electron cooling times requires an accurate description of the dynamical friction force. The proposed RHIC cooler will require ~55 MeV electrons, which must be obtained from an RF linac, leading to very high transverse electron temperatures. A strong solenoid will be used to magnetize the electrons and suppress the transverse temperature, but the achievable magnetized cooling logarithm will not be large. Available formulas for magnetized dynamical friction are derived in the logarithmic approximation, which is questionable in this regime. In this paper, we explore the magnetized friction force for parameters of the RHIC cooler, using the VORPAL code.* VORPAL can simulate dynamical friction and diffusion coefficients directly from first principles.** Various aspects of the friction force, such as dependence on magnetic field, scaling with ion charge number and others, are addressed for the problem of high-energy electron cooling in the RHIC regime.

Moderator clean-up system in a heavy water reactor

International Nuclear Information System (INIS)

Sasada, Yasuhiro; Hamamura, Kenji.

1983-01-01

Purpose: To decrease the fluctuation of the poison concentration in heavy water moderator due to a heavy water clean-up system. Constitution: To a calandria tank filled with heavy water as poison-containing moderators, are connected both end of a pipeway through which heavy water flows and to which a clean-up device is provided. Strongly basic resin is filled within the clean-up device and a cooler is disposed to a pipeway at the upstream of the clean-up device. In this structure, the temperature of heavy water at the inlet of the clean-up device at a constant level between the temperature at the exit of the cooler and the lowest temperature for the moderator to thereby decrease the fluctuation in the poison concentration in the heavy water moderator due to the heavy water clean-up device. (Moriyama, K.)

Commissioning of the LEIR electron cooler with Pb$^{+54}$ ions

CERN Document Server

Tranquille, G; Carly, Ch; Prieto, V; Sautier, R; Bubley, A; Parkhomchuk, V; Reva, V; Brizgunov, M; Vedenev, M; Panasyuk, V

2006-01-01

The new LEIR cooler with a variable profile of the electron beam and electrostatic bending was commissioned in 2005-2006. In this paper we present our experience with the commissioning of the new device as well as the first results of the ion beam Pb +54 cooling with a high-intensity variable-density electron beam.

Characterization of a thermoelectric cooler based thermal management system under different operating conditions

International Nuclear Information System (INIS)

Russel, M.K.; Ewing, D.; Ching, C.Y.

2013-01-01

The performance of a thermoelectric cooler (TEC) based thermal management system for an electronic packaging design that operates under a range of ambient conditions and system loads is examined using a standard model for the TEC and a thermal resistance network for the other components. Experiments were performed and it was found that the model predictions were in good agreement with the experimental results. An operating envelope is developed to characterize the TEC based thermal management system for peak and off peak operating conditions. Parametric studies were performed to analyze the effect of the number of TEC module(s) in the system, geometric factor of the thermo-elements and the cold to hot side thermal resistances on the system performance. The results showed that there is a tradeoff between the extent of off peak heat fluxes and ambient temperatures when the system can be operated at a low power penalty region and the maximum capacity of the system. - Highlights: ► A model was developed for thermal management systems using thermoelectric coolers. ► Model predictions were in good agreement with experimental results. ► An operating envelope was developed for peak and off peak conditions. ► The effect of the number of thermoelectric coolers on the system was determined.

Optimal analysis of gas cooler and intercooler for two-stage CO2 trans-critical refrigeration system

International Nuclear Information System (INIS)

Li, Wenhua

2013-01-01

Highlights: • Simplified model for tube-fin gas cooler for CO 2 refrigeration system was presented and validated. • Several parameters were investigated using 1st law and 2nd law in component and system level. • Practical guidelines of optimum for tube-fin gas cooler and intercooler were proposed. - Abstract: Energy-based 1st law and exergy-based 2nd law are both employed in the paper to assess the optimal design of gas cooler and intercooler for two-stage CO 2 refrigeration system. A simplified mathematical model of the air-cooled coil is presented and validated against experimental data with good accuracy. The optimum circuit length under the influence of frontal air velocity and deep rows is investigated first. Thereafter, designed coil with optimum circuit length is further evaluated within the two-stage refrigeration system. It is found out the optimum point using 1st law does not coincide with the point using 2nd law in isolated component and the simulation results from isolated component by 2nd law are closer to system analysis. Results show optimum circuit length is much bigger for gas cooler than intercooler and the influence on the length from variation of frontal air velocity and deep rows may be neglected. There does exist optimum frontal air velocity which will decrease with more number of deep rows

Note: Wide-operating-range control for thermoelectric coolers

Science.gov (United States)

Peronio, P.; Labanca, I.; Ghioni, M.; Rech, I.

2017-11-01

A new algorithm for controlling the temperature of a thermoelectric cooler is proposed. Unlike a classic proportional-integral-derivative (PID) control, which computes the bias voltage from the temperature error, the proposed algorithm exploits the linear relation that exists between the cold side's temperature and the amount of heat that is removed per unit time. Since this control is based on an existing linear relation, it is insensitive to changes in the operating point that are instead crucial in classic PID control of a non-linear system.

Integral finned heater and cooler for stirling engines

Science.gov (United States)

Corey, John A.

1984-01-01

A piston and cylinder for a Stirling engine and the like having top and bottom meshing or nesting finned conical surfaces to provide large surface areas in close proximity to the working gas for good thermal (addition and subtraction of heat) exchange to the working gas and elimination of the usual heater and cooler dead volume. The piston fins at the hot end of the cylinder are perforated to permit the gas to pass into the piston interior and through a regenerator contained therein.

Improving the Efficiency of the Heat Pump Control System of Carbon Di-oxide Heat Pump with Several Evaporators and Gas Coolers

OpenAIRE

Sit, M.L.; Juravliov, A.A.; Sit, B.M.; Timchenko, D.

2016-01-01

The problem of coordination of the values of the refrigerant flow through the evaporators and gas coolers of the heat pump for the simultaneous production of heat and cold is studied. The compensation of the variations of the total flow through the evaporators is implemented using the variation of the capacity of the compressor and a corresponding change in flow through the auxiliary gas cooler of the heat pump. Control system of this gas cooler is constructed using the invariance principle o...

Desiccant Dewpoint Cooling System Independent of External Water Sources

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Markussen, Wiebke B.

2015-01-01

the air that regenerates the desiccant dehumidifier, and using it for running the evaporative coolers in the system. A closed regeneration circuit is used for maximizing the amount of condensed water. This solution is applied to a system with a desiccant wheel dehumidifier and a dew point cooler, termed...... desiccant dew-point cooling system, for demonstrating its function and applicability. Simulations are carried out for varying outdoor conditions under constant supply conditions. The results show that the system is independent of external water supply for the majority of simulated conditions. In comparison...... to the desiccant dew-point system without water recovery, the required regeneration temperature increases and the system thermal efficiency decreases....

How is the operation of a dew point cooler effected? Part 1; Waardoor wordt de werking van een daupuntkoeler beinvloed? Deel 1

Energy Technology Data Exchange (ETDEWEB)

Janssen, M. [Re/genT, Helmond (Netherlands); Uges, P.G.H. [StatiqCooling, Rijssen (Netherlands)

2010-11-15

A dewpoint cooler is defined as an indirect evaporative cooler with a countercurrent heat exchanger that cools the primary air, humidifies the process air and exudes it to the environment. Because of the countercurrent heat exchanger, the air outlet temperature is not limited to the wet bulb temperature. The structure consists of polypropylene slabs in which the primary air flow is conducted through the channels. The plates are covered with a hygroscopic foil. The process air is forced to flow between the plates and thus comes into direct contact with the foil. Water is supplied to the foil by means of a distribution system. A number of such systems has been experimentally investigated by Re/genT by order of StatiqCooling. [Dutch] Een dauwpuntkoeler wordt gedefinieerd als een indirecte verdampingskoeler met een tegenstroom warmtewisselaar die de primaire lucht koelt en de proceslucht bevochtigt en afgeeft aan de omgeving. Door de tegenstroomwarmtewisselaar is de luchtuitblaastemperatuur niet beperkt tot de natteboltemperatuur. De constructie bestaat uit polipropyleen kanaalplaten waarbij de primaire luchtstroom door de kanalen geleid wordt. De platen zijn bedekt met een hygroscopische folie. De proceslucht wordt gedwongen tussen de platen door te stromen en komt daarmee in direct contact met de folie. Aan de folie wordt water toegevoerd door middel van een distributiesysteem. Een aantal van dergelijke installaties is in opdracht van StatiqCooling experimenteel onderzocht door Re/genT.

Effects of PM fouling on the heat exchange effectiveness of wave fin type EGR cooler for diesel engine use

Science.gov (United States)

Jang, Sang-Hoon; Hwang, Se-Joon; Park, Sang-Ki; Choi, Kap-Seung; Kim, Hyung-Man

2012-06-01

Developing an effective method of reducing nitrogen oxide emissions is an important goal in diesel engine research. The use of cooled exhaust gas recirculation has been considered one of the most effective techniques of reducing nitrogen oxide. However, since the combustion characteristics in a diesel engine involves high temperature and load, the amount of particulate matter emission tends to increase, and there is a trade-off between the amount of nitrogen oxide and particulate matter emissions. In the present study, engine dynamometer experiments are performed to investigate the effects of particulate matter fouling on the heat exchange characteristics of wave fin type exhaust gas recirculation coolers that have four cases of two wave pitch and three fin pitch lengths. To optimize the fin and wave pitches of the EGR cooler, the exhaust gas temperature, pressure drop and heat exchange effectiveness are compared. The experimental results show that the exhaust gas recirculation cooler with a fin pitch of 3.6 mm and a wave pitch of 8.8 mm exhibits better heat exchange characteristics and smaller particulate matter fouling effect than the other coolers.

40 CFR 63.1348 - Standards for affected sources other than kilns; in-line kiln/raw mills; clinker coolers; new and...

Science.gov (United States)

2010-07-01

... than kilns; in-line kiln/raw mills; clinker coolers; new and reconstructed raw material dryers; and raw and finish mills. 63.1348 Section 63.1348 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...; in-line kiln/raw mills; clinker coolers; new and reconstructed raw material dryers; and raw and...

Heat Exchange and Fouling Analysis on a Set of Hydrogen Sulphide Gas Coolers

Directory of Open Access Journals (Sweden)

Andrés Adrian Sánchez-Escalona

2017-07-01

Full Text Available The sulphide acid coolers are tube and shell jacketed heat exchangers designed to cool down the produced gas from 416,15 K to 310,15 K in addition to separate the sulphur carried over by the outlet gas from the reactor tower. The investigation was carried out by applying the passive experimentation process in an online cooler set in order to determine the heat transfer rates and fouling based on heat resistance. It was corroborated that the operation of this equipment outside design parameters increases outlet gas temperature and liquid sulphur carryovers. Efficiency loss is caused by fouling elements in the fluid, which results in changes in the overall heat transfer rate. The linear tendency of the fouling heat resistance based on time for three gas flowrates.

Topology optimisation of passive coolers for light-emitting diode lamps

DEFF Research Database (Denmark)

Alexandersen, Joe

2015-01-01

This work applies topology optimisation to the design of passive coolers for light-emitting diode (LED) lamps. The heat sinks are cooled by the natural convection currents arising from the temperature difference between the LED lamp and the surrounding air. A large scale parallel computational....... The optimisation results show interesting features that are currently being incorporated into industrial designs for enhanced passive cooling abilities....

An experimental study of trans-critical CO2 water–water heat pump using compact tube-in-tube heat exchangers

International Nuclear Information System (INIS)

Jiang, Yuntao; Ma, Yitai; Li, Minxia; Fu, Lin

2013-01-01

Highlights: • Thermodynamic analyses of transcritical CO 2 cycle with and without IHX are provided. • A transcritical CO 2 heat pump system adopts compact tube-in-tube heat exchangers. • Experiment results of systems with and without IHX have been analyzed and compared. • IHX can improve the performance of the transcritical CO 2 heat pump system. - Abstract: A transcritical CO 2 water–water heat pump system is introduced in this study, which employs compact tube-in-tube evaporator and gas cooler. Its primary test standards and operating conditions are introduced. Under test conditions, experiments have been carried out with compression cycles with and without internal heat exchanger (IHX). Experiment results have been analyzed and compared, showing that IHX can improve the coefficient of performance of the system. The analyses are done mainly on the variations of outlet CO 2 temperature of the gas cooler, compressor discharge pressure, compressor lubricant temperature, hot water mass flow rate, etc. When the inlet water temperature of the gas cooler is 15 °C, 20 °C, 25 °C respectively, the hot water temperature ranges from 45 °C to 70 °C, the relative COP h (coefficient of performance when heating) change index (RCI COP ) of the heat pump system with IHX is about 3.5–8% higher than that without IHX. The relative capacity change index (RCI Q ) of the heat pump system with IHX is about 5–10% higher than that without IHX. Temperature of CO 2 increases at the outlet of the gas cooler when the outlet water temperature of the gas cooler increases. Lowering the outlet CO 2 temperature of the gas cooler is an important way to improve the performance of the system

Design and performance of an RFQ cooler and buncher

Energy Technology Data Exchange (ETDEWEB)

Szerypo, J.; Ban, G.; Le Brun, C.; Delahaye, P.; Lienard, E.; Mauger, F.; Naviliat, O.; Tamain, B. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Hennecart, D. [Centre Interdisciplinaire de Recherche Ions Lasers, 14 - Caen (France)

1999-10-01

Several new experiments, planned or in preparation at low energy radioactive beam facilities, require the cooling and bunching of radioactive beams. This may be performed with a radiofrequency quadruple (RFQ) cooler and buncher, where the ions are cooled in a buffer gas while being guided by an oscillating RFQ field. This work describes the performance of such a device, which has been designed and studied in order to be extended for the cooling of light ions. The analysis requires extensive computer simulations, which are done with two approaches: the macroscopic and the microscopic. The latter approach is able to account for the RF-heating effect and the calculations were performed by the monte Carlo method. The cooling formalism was extendedto include a charge-exchange effect. The charge-exchange cross sections were calculated theoretically in a quantum-mechanical formalism for different ion-atom combinations. The simulations have shown in particular that for the cooling of {sup 6}He{sup +} ions, {sup 4}He is excluded as buffer gas because of the resonant charge exchange processes which drastically decreases the transmission. On the other hand, the cooling of {sup 6}He{sup +} ions with H{sub 2} as buffer gas appears as a promising solution. The most relevant cooler design parameters are proposed. A project of a complete system, including the deceleration, extraction and transfer sections, is presented. (authors)

Chemical composition and water quality of Tashlyk Water-cooling reservoir of South-Ukraine NPP

International Nuclear Information System (INIS)

Kosheleva, S.I.; Gajdar, E.M.

1995-01-01

Information about water quality in Tashlyk water reservoir (cooler of South-Ukrainian NPP) during 9 years (1980-1992) is presented. Comparative data about Water Quality of South Bug (its source of water nutrition) and this reservoir point on the periodical pollution by surface waters and industrial wastes with a great contain of sulphates and chlorides. The class of water has been changed from hydrocarbonat calcium to sulfur-chlorine-magnesium or chlorine-natrium. The contain of biogenic and organic components in reservoir's water has been corresponded to the main class of waters satisfactory cleanliness

Improvement of the cooldown time of LSF 9599 flexure bearing SADA cooler

NARCIS (Netherlands)

Mullié, J.; Groep, van der W.; Bruins, P.; Benschop, T.; Koning, de A.; Dam, J.A.M.; Andresen, B.F.; Fulop, G.F.; Norton, P.R.

2006-01-01

Thales Cryogenics has presented the LSF 9599 SADA II flexure cooler in 2005. Based on Thales' well-known moving magnet flexure technology, the LSF 9599 complies with the SADA II specification with respect to performance, envelope and mass. Being the first manufacturer offering a full flexure-bearing

Data exchange system in cooler-storage-ring virtual accelerator

International Nuclear Information System (INIS)

Liu Wufeng; Qiao Weimin; Jing Lan; Guo Yuhui

2009-01-01

The data exchange system of the cooler-storage-ring (CSR) control system for heavy ion radiotherapy has been introduced for the heavy ion CSR at Lanzhou (HIRFL-CSR). Using techniques of Java, component object model (COM), Oracle, DSP and FPGA, this system can achieve real-time control of magnet power supplies sanctimoniously, and control beams and their switching in 256 energy levels. It has been used in the commissioning of slow extraction for the main CSR (CSRm), showing stable and reliable performance. (authors)

Development and Testing of an Integrated Sandia Cooler Thermoelectric Device (SCTD).

Energy Technology Data Exchange (ETDEWEB)

Johnson, Terry A.; Staats, Wayne Lawrence,; Leick, Michael Thomas; Zimmerman, Mark D.; Radermacher, Reinhard; Martin, Cara; Nasuta, Dennis; Kalinowski, Paul; Hoffman, William

2014-12-01

This report describes a FY14 effort to develop an integrated Sandia Cooler T hermoelectric D evice (SCTD) . The project included a review of feasible thermoelectric (TE) cooling applications, baseline performance testing of an existing TE device, analysis and design development of an integrated SCTD assembly, and performance measurement and validation of the integrated SCTD prototype.

Elimination of Acid Cleaning of High Temperature Salt Water Heat Exchangers: Redesigned Pre-Production Full-Scale Heat Pipe Bleed Air Cooler for Shipboard Evaluation

Science.gov (United States)

2011-11-01

Acronyms ASW Anti Submarine Warfare AUX Auxillary Room BAC Bleed Air Cooler BAS Bleed Air System BTU British Thermal Unit BOSS...improvements which should be considered when making a production decision following successful shipboard tests. 5. Since this technology was proposed...However, to maintain schedule, a decision was made prior to this structural analysis being completed on how long to make the heat pipes. With using the

Linear motor driven Stirling coolers for military and commercial applications

International Nuclear Information System (INIS)

Berry, R.

1992-01-01

This paper discusses the design and performance of a miniature, closed cycle, split stirling, cryogenic cooler that provides 1 watt of cooling at 80 K. The compressor uses two opposed linear motors to drive opposed pistons and the expander uses a pneumatically driven displacer. A single electronics module and compressor has been developed to drive three different expanders that have nominal cold cylinder diameters of 5, 8 and 13 mm

Effects of PM fouling on the heat exchange effectiveness of wave fin type EGR cooler for diesel engine use

Energy Technology Data Exchange (ETDEWEB)

Jang, Sang-Hoon; Hwang, Se-Joon; Choi, Kap-Seung; Kim, Hyung-Man [INJE University, Department of Mechanical Engineering, High Safety Vehicle Core Technology Research Center, Gimhae-si, Gyeongnam-do (Korea, Republic of); Park, Sang-Ki [Hanyang University, Graduate School of Mechanical Engineering, Ansan, Gyeonggido (Korea, Republic of)

2012-06-15

Developing an effective method of reducing nitrogen oxide emissions is an important goal in diesel engine research. The use of cooled exhaust gas recirculation has been considered one of the most effective techniques of reducing nitrogen oxide. However, since the combustion characteristics in a diesel engine involves high temperature and load, the amount of particulate matter emission tends to increase, and there is a trade-off between the amount of nitrogen oxide and particulate matter emissions. In the present study, engine dynamometer experiments are performed to investigate the effects of particulate matter fouling on the heat exchange characteristics of wave fin type exhaust gas recirculation coolers that have four cases of two wave pitch and three fin pitch lengths. To optimize the fin and wave pitches of the EGR cooler, the exhaust gas temperature, pressure drop and heat exchange effectiveness are compared. The experimental results show that the exhaust gas recirculation cooler with a fin pitch of 3.6 mm and a wave pitch of 8.8 mm exhibits better heat exchange characteristics and smaller particulate matter fouling effect than the other coolers. (orig.)

Studies and conception of a radiofrequency cooler for high intensity beams

International Nuclear Information System (INIS)

Duval, Florian

2009-01-01

The topic of this thesis is the study and the conception of a RFQ Cooler with buffer gas for high intensity radioactive beams. This project is in the frame of the next extension of GANIL, Spiral2, and the future low-energy facility DESIR ('Decay, Excitation and Storage of Radioactive ions'). The goal is to reduce the beams emittance of Spiral2 beams to allow their purification (ideally at isobaric level) with a high resolution separator. This cooler consists on a quadrupolar structure on which ions are confined by RF potential in opposite phase at an energy of 100 eV. A light buffer-gas, typically helium, is injected in the quadrupole and, after each collision, the ion lose a part of its energy and is finally cooled. The main problem on our project concerns the space charge. The existing devices are able to cool currents of few 10 nA whereas we have to treat beam intensities around 1 μA which induce an increase of the Coulomb repulsion between ions. That needs to produce strong RF fields which induce high RF potentials (≅ 10 kV_p_p) and a low inner radius (r_0 ≅ 3 a 5 mm). We have worked on a first prototype, SHIRaC-Phase1 ('Spiral2 High Intensity Radiofrequency Cooler'), with a 3 mm-inner radius, built at CSNSM-Orsay and moved at LPC-Caen at the end of 2007. The main R and D effort concerns the electronic part. A first RF system, based on a LC resonant circuit, has been developed and has provided up to 2500 V_p_p between 4.5 and 6.3 MHz. In these conditions, we have checked that we didn't have strong limitations from electrical breakdown between our electrodes. With this device, we have reduced the beam emittance to a value around 2 π.mm.mrad at 60 keV and the longitudinal energy spread to 146 meV. The maximum transmission of Sodium "2"3Na"+ and Rubidium "8"7Rb"+ is 25% with an ionization source for which the beam quality is better than Spiral2. For this reason, we have conceived a new cooler with an acceptance of 80 π.mm.mrad at 60 keV. This second

Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

Science.gov (United States)

Johnston, James D; Tuttle, Steven C; Nelson, Morgan C; Bradshaw, Rebecca K; Hoybjerg, Taylor G; Johnson, Julene B; Kruman, Bryce A; Orton, Taylor S; Cook, Ryan B; Eggett, Dennis L; Weber, K Scott

2016-01-01

Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr) and summer (July-Sept), 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction.

ANALISIS PERFORMA SISTEM PENDINGIN RAMAH LINGKUNGAN UNTUK KABIN MOBIL CITY CAR MENGGUNAKAN MODUL TERMO ELECTRIC COOLER TERHADAP KONSUMSI BAHAN BAKAR

Directory of Open Access Journals (Sweden)

Mirza Yusuf

2017-12-01

Full Text Available Ramah lingkungan menjadi isu yang gencar dalam penelitian. Cloro Fluoro Carbon (CFC yang digunakan dalam AC konvensional akan menguap ke udara bebas  berdampak kerusakan lapisan ozon. Ditinjau secara micro dalam penggunaan sitem pendingin dapat diterapkan pada pendingin kabin mobil. System pendingin mobil konfensional menimbulkan 2 kerugian yaitu lebih boros bahan bakar karena couple pulley compressor AC membebani putaran mesin dan penggunaan CFC yang tidak ramah lingkungan.   System pendingin ramah lingkunagan dan mampu menghemat bahan bakar mesin tersebut dapat kita temukan pada modul thermoelectric.  terobosan baru sistem pendingin tersebut menggunakan modul pendingin Thermo Electric Cooler (TEC yang memanfaatkan sisi dingin pada Thermo Electric Cooler (TEC dengan memanfaatkan seaback effect .  Thermo Electric Cooler (TEC ketika dialiri tegangan DC (arus searah pada kedua jalur kabel penghubungnya maka salah satu sisi akan menjadi panas, sementara sisi satunya akan menjadi dingin. Salahsatu cara yang dapat ditempuh untuk memaksimalkan proses pendinginan, maka sisi panas Thermo Electric Cooler (TEC harus diturunkan temperaturenya serendah mungkin mungkin dengan menggunakan alat penukar kalor heat sink serta dibantu kipas(fan. semakin lama proses pendinginan, maka semakin optimal suhu ruangan yang didinginkan. Dari data Hasil pengujian dapat diketahui perangkat pendingin tersebut mampu bekerja dengan rate penurunan temperature memadai. Selanjutnya dapat dapat diaplikasikan sebagai alat pendingin ruangan yang efektif, efisien dan ramah lingkungan.    Kata kunci:  Kabin mobil, Air Conditioner (AC konvensional, Cloro Fluoro Carbon (CFC, Thermo Electric Cooler (TEC, komponen sistem pendingin.

Nanoscale coatings for erosion and corrosion protection of copper microchannel coolers for high powered laser diodes

Science.gov (United States)

Flannery, Matthew; Fan, Angie; Desai, Tapan G.

2014-03-01

High powered laser diodes are used in a wide variety of applications ranging from telecommunications to industrial applications. Copper microchannel coolers (MCCs) utilizing high velocity, de-ionized water coolant are used to maintain diode temperatures in the recommended range to produce stable optical power output and control output wavelength. However, aggressive erosion and corrosion attack from the coolant limits the lifetime of the cooler to only 6 months of operation. Currently, gold plating is the industry standard for corrosion and erosion protection in MCCs. However, this technique cannot perform a pin-hole free coating and furthermore cannot uniformly cover the complex geometries of current MCCs involving small diameter primary and secondary channels. Advanced Cooling Technologies, Inc., presents a corrosion and erosion resistant coating (ANCERTM) applied by a vapor phase deposition process for enhanced protection of MCCs. To optimize the coating formation and thickness, coated copper samples were tested in 0.125% NaCl solution and high purity de-ionized (DIW) flow loop. The effects of DIW flow rates and qualities on erosion and corrosion of the ANCERTM coated samples were evaluated in long-term erosion and corrosion testing. The robustness of the coating was also evaluated in thermal cycles between 30°C - 75°C. After 1000 hours flow testing and 30 thermal cycles, the ANCERTM coated copper MCCs showed a corrosion rate 100 times lower than the gold plated ones and furthermore were barely affected by flow rates or temperatures thus demonstrating superior corrosion and erosion protection and long term reliability.

Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

Directory of Open Access Journals (Sweden)

James D Johnston

Full Text Available Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr and summer (July-Sept, 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction.

Micromachined Joule-Thomson coolers for cooling low-temperature detectors and electronics

Science.gov (United States)

ter Brake, Marcel; Lerou, P. P. P. M.; Burger, J. F.; Holland, H. J.; Derking, J. H.; Rogalla, H.

2017-11-01

The performance of electronic devices can often be improved by lowering the operating temperature resulting in lower noise and larger speed. Also, new phenomena can be applied at low temperatures, as for instance superconductivity. In order to fully exploit lowtemperature electronic devices, the cryogenic system (cooler plus interface) should be `invisible' to the user. It should be small, low-cost, low-interference, and above all very reliable (long-life). The realization of cryogenic systems fulfilling these requirements is the topic of research of the Cooling and Instrumentation group at the University of Twente. A MEMS-based cold stage was designed and prototypes were realized and tested. The cooler operates on basis of the Joule-Thomson effect. Here, a high-pressure gas expands adiabatically over a flow restriction and thus cools and liquefies. Heat from the environment (e.g., an optical detector) can be absorbed in the evaporation of the liquid. The evaporated working fluid returns to the low-pressure side of the system via a counter-flow heat exchanger. In passing this heat exchanger, it takes up heat from the incoming high-pressure gas that thus is precooled on its way to the restriction. The cold stage consists of a stack of three glass wafers. In the top wafer, a high-pressure channel is etched that ends in a flow restriction with a height of typically 300 nm. An evaporator volume crosses the center wafer into the bottom wafer. This bottom wafer contains the lowpressure channel thus forming a counter-flow heat exchanger. A design aiming at a net cooling power of 10 mW at 96 K and operating with nitrogen as the working fluid was optimized based on the minimization of entropy production. The optimum cold finger measures 28 mm x 2.2 mm x 0.8 mm operating with a nitrogen flow of 1 mg/s at a high pressure of 80 bar and a low pressure of 6 bar. The design and fabrication of the coolers will be discussed along with experimental results.

Insulated Containers for Bottled Water (ICB)-Performance Evaluation

Science.gov (United States)

2017-04-21

Plastic   Wrapped  Cordura  Rubberized traction pad  PE  Plastic   Liner  No  Yes  Yes  No  Safe Tie‐Down  Capability  Yes  Yes  Yes  No  Easy Access...mounted Soldiers. The ICBs are lighter, require less storage space, and have more effective tie-down characteristics than coolers often used to carry...bottled water in vehicles. The performance of the ICBs and a commonly used cooler was assessed to determine whether the easier-to-stow ICBs would be as

Effect of cooler electrons on a compressive ion acoustic solitary wave in a warm ion plasma — Forbidden regions, double layers, and supersolitons

International Nuclear Information System (INIS)

Ghosh, S. S.; Sekar Iyengar, A. N.

2014-01-01

It is observed that the presence of a minority component of cooler electrons in a three component plasma plays a deterministic role in the evolution of solitary waves, double layers, or the newly discovered structures called supersolitons. The inclusion of the cooler component of electrons in a single electron plasma produces sharp increase in nonlinearity in spite of a decrease in the overall energy of the system. The effect maximizes at certain critical value of the number density of the cooler component (typically 15%–20%) giving rise to a hump in the amplitude variation profile. For larger amplitudes, the hump leads to a forbidden region in the ambient cooler electron concentration which dissociates the overall existence domain of solitary wave solutions in two distinct parameter regime. It is observed that an inclusion of the cooler component of electrons as low as < 1% affects the plasma system significantly resulting in compressive double layers. The solution is further affected by the cold to hot electron temperature ratio. In an adequately hotter bulk plasma (i.e., moderately low cold to hot electron temperature ratio), the parameter domain of compressive double layers is bounded by a sharp discontinuity in the corresponding amplitude variation profile which may lead to supersolitons

Effect of cooler electrons on a compressive ion acoustic solitary wave in a warm ion plasma — Forbidden regions, double layers, and supersolitons

Energy Technology Data Exchange (ETDEWEB)

Ghosh, S. S., E-mail: sukti@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410218 (India); Sekar Iyengar, A. N. [Plasma Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India)

2014-08-15

It is observed that the presence of a minority component of cooler electrons in a three component plasma plays a deterministic role in the evolution of solitary waves, double layers, or the newly discovered structures called supersolitons. The inclusion of the cooler component of electrons in a single electron plasma produces sharp increase in nonlinearity in spite of a decrease in the overall energy of the system. The effect maximizes at certain critical value of the number density of the cooler component (typically 15%–20%) giving rise to a hump in the amplitude variation profile. For larger amplitudes, the hump leads to a forbidden region in the ambient cooler electron concentration which dissociates the overall existence domain of solitary wave solutions in two distinct parameter regime. It is observed that an inclusion of the cooler component of electrons as low as < 1% affects the plasma system significantly resulting in compressive double layers. The solution is further affected by the cold to hot electron temperature ratio. In an adequately hotter bulk plasma (i.e., moderately low cold to hot electron temperature ratio), the parameter domain of compressive double layers is bounded by a sharp discontinuity in the corresponding amplitude variation profile which may lead to supersolitons.

Cooler reflective pavements give benefits beyond energy savings: durability and illumination

International Nuclear Information System (INIS)

Pomerantz, Melvin; Akbari, Hashem; Harvey, John T.

2000-01-01

City streets are usually paved with asphalt concrete because this material gives good service and is relatively inexpensive to construct and maintain. We show that making asphalt pavements cooler, by increasing their reflection of sunlight, may lead to longer lifetime of the pavement, lower initial costs of the asphalt binder, and savings on street lighting and signs. Excessive glare due to the whiter surface is not likely to be a problem

Improving eco-sustainable characteristics and energy efficiency of evaporative fluid cooler via experimental and numerical study

Directory of Open Access Journals (Sweden)

Rašković Predrag O.

2008-01-01

Full Text Available This paper presents an on-going research project that aims to identify possibilities for wider use of evaporative cooling in process industry, especially the use of evaporative fluid cooler units. Experimental study is performed on small scale evaporative fluid cooler, while the correlation based model has been carried out to explore the detailed heat and mass transfer processes inside this unit. Numerical integration of mathematical model is executed by new approach, based on differential, collocation Simpson method. Proposed models have been verified by comparing the computed results with those obtained by the experimental measurements. The results of research will enable the creation of more comprehensive simulation software, with wider range of operating and construction parameters.

Gasket structure improvement for the spent fuel pool cooler

International Nuclear Information System (INIS)

Li Yun; He Shaohua; Qi Hongchang; Wang Cong; Wang Chenglin; Zhong Boling

2014-01-01

The two spent fuel pool coolers for the 320 MW unit in CNNC Nuclear Power Operation Management Co., Ltd. have operated for more than 20 years. In accordance with the preventive maintenance programs, they must be overhauled. It is decided to improve the original gasket structure of the component and adopt the method of a short-length U-tubes pulling after analysis and study. There are no leakages and other abnormal situations after the equipment being put into operation. The unit is kept safe and stable. At the same time, thought and method for the maintenance of other similar equipment are provided. (authors)

Study of beam dynamics at cooler synchrotron TARN-II

International Nuclear Information System (INIS)

Watanabe, S.; Katayama, T.; Watanabe, T.; Yoshizawa, M.; Tomizawa, M.; Chida, K.; Arakaki, Y.; Noda, K.; Kanazawa, M.

1992-08-01

Several kinds of beam diagnostic instruments, have been developed at cooler-synchrotron TARN-II. These are intended to study beam dynamics at low beam current of several microamperes and then have high sensitivity of good S/N ratio. In addition, the acceleration system, especially low level RF system, has been improved to attain the maximum beam energy. With the successful performance of these instrumentations, the study of beam dynamics are presently being carried out. For example, the synchrotron acceleration of the light ions was achieved up to 220 MeV/u without any beam loss. (author)

Experimental investigation of the performance of an elbow-bend type heat exchanger with a water tube bank used as a heater or cooler in alpha-type Stirling machines

Energy Technology Data Exchange (ETDEWEB)

El-Ehwany, A.A.; Hennes, G.M. [Mech. Power Dept., Faculty of Eng., Ain Shams University, Cairo (Egypt); Eid, E.I. [Mech. Dept., Faculty of Ind. Education, Suez Canal University, Suez 43515 (Egypt); El-Kenany, E. [The Specialized Studies Academy, Workers University, Tech. Dept., Mansura (Egypt)

2011-02-15

In this work the effect of the elbow-bend geometry and the effect of the tube arrangement on the performance of air-to-water heat exchanger is studied experimentally. In elbow-bend heat exchanger, the direction of the working fluid is bended at 90 degrees to its inlet direction. The heating or cooling fluid flows inside straight tubes while the working fluid flows past the tubes along an elbow pass. Three different types of the geometry of the elbow with three different tube bank arrangements were studied. The results were plotted and analyzed to clarify the effects of the elbow-bend geometry, the tube bank arrangements and the dead volume in the heat exchanger on the heat transfer and pressure drop. Two empirical correlations were deduced for each design, one to predict the relation between Nusselt and Reynolds numbers, while the other relation is between the friction factor and Reynolds number. This work was done to select the more suitable design to be used as a heater or a cooler in Stirling machines. (author)

Synthetical optimization of hydraulic radius and acoustic field for thermoacoustic cooler

International Nuclear Information System (INIS)

Kang Huifang; Li Qing; Zhou Gang

2009-01-01

It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of hydraulic radius and acoustic field which is characterized by the ratio of the traveling wave component to the standing wave component. In this paper, we discussed the heat flux, cooling power, temperature gradient and coefficient of performance of thermoacoustic cooler with different combinations of hydraulic radiuses and acoustic fields. The calculation results show that, in the cooler's regenerator, due to the acoustic wave, the heat is transferred towards the pressure antinodes in the pure standing wave, while the heat is transferred in the opposite direction of the wave propagation in the pure traveling wave. The better working condition for the regenerator appears in the traveling wave phase region of the like-standing wave, where the directions of the heat transfer by traveling wave component and standing wave component are the same. Otherwise, the small hydraulic radius is not a good choice for acoustic field with excessively high ratio of traveling wave, and the small hydraulic radius is only needed by the traveling wave phase region of like-standing wave.

Laser spectroscopy of gallium isotopes using the ISCOOL RFQ cooler

CERN Multimedia

Blaum, K; Kowalska, M; Ware, T; Procter, T J

2007-01-01

We propose to study the radioisotopes of gallium (Z=31) by collinear laser spectroscopy using the ISCOOL RFQ ion cooler. The proposed measurements on $^{62-83}$Ga will span both neutron-deficient and neutron-rich isotopes. Of key interest is the suggested development of a proton-skin in the neutron-deficient isotopes. The isotope shifts measured by laser spectroscopy will be uniquely sensitive to this feature. The measurements will also provide a wealth of new information on the gallium nuclear spins, static moments and nuclear charge radii.

Impact of an Ultraviolet Reactor on the Improvement of Air Quality Leaving a Direct Evaporative Cooler

Directory of Open Access Journals (Sweden)

Wonjun Kim

2018-04-01

Full Text Available The purpose of this study is to improve microbial air quality by improving water quality, particularly concerning microbiological aspects, by applying an ultraviolet water purifier system to a direct evaporative cooling (DEC system. A direct evaporative cooler is an air cooling technique that uses the evaporation of water. Most DECs recirculate water to reduce water use. Evaporative cooling pads and water are biologically contaminated by recirculating water. This contamination can develop into air contamination and cause respiratory illnesses in occupants. It is necessary to use sterilized water in a DEC to prevent respiratory diseases and maintain air quality. In this study, we examine whether improvements in water quality in a DEC affect air quality by dividing experiments into a control group (Control and a treated group (UV-treated. In the control group, the degree of contamination was measured when a DEC operated for four weeks without ultraviolet water treatment. In UV-treated, the degree of contamination was measured when UV water treatment was applied to a DEC for four weeks. In both Control and UV-treated, microbes were sampled from the water, the evaporative cooling pad surface, and the DEC inlet and outlet air samples in order to compare the levels of contamination. The surface was measured once at four points, and the air was measured four times at two points. A comparison of the two experiments indicated that the degree of microbial contamination of water and air was significantly reduced in the UV-treated group when compared to that in the control group. When the pollution degree of the evaporative cooling pad was compared to the degree of air pollution, it was difficult to obtain a correlation between the two factors, although the results confirmed that the contamination of the evaporative cooling pad caused water pollution. Therefore, it is necessary to operate a water treatment system to maintain the clean air in DECs.

Method for separation of water from bituminous shales, etc. [water-free heavy product and water-containing light product

Energy Technology Data Exchange (ETDEWEB)

Hellsing, G H

1908-10-13

The method is characterized by conducting all the products of distillation, coming from the retorts, into a controllable system of condensation. This system of condensation is so constructed that the products of distillation are cooled to such a temperature that only the water-free heavy distillates are being condensed, and is furthermore so constructed that the other products of distillation, not yet condensed, are being condensed in an ordinary system of coolers. The purpose is to separate the distillates into a water-free heavy product and a water-containing lighter product. The patent includes an additional claim.

Influence of constructive parameters on the performance of two indirect evaporative cooler prototypes

International Nuclear Information System (INIS)

Tejero-González, Ana; Andrés-Chicote, Manuel; Velasco-Gómez, Eloy; Rey-Martínez, Francisco Javier

2013-01-01

Two equally-sized cross-flow heat-exchanger prototypes have been designed with a total heat exchange area of 6 m 2 and 3 m 2 respectively, constructed with polycarbonate hollow panels of different cross section. They are connected into a heat-recovery cycle within the whole experimental setup constructed for the tests, which mainly consists of: an Air Handling Unit to simulate the outdoor airstream conditions, a conditioned climate chamber, and a water circuit to provide the water supply required. They have been experimentally characterised in two operating modes in order to determine how evaporative cooling improves heat recovery in each case, focussing on the influence of modifying the constructive characteristics. To perform the evaporative cooling process, water is supplied to the exhaust airstream. Results are studied considering how constructive issues, outdoor air volume flow rate and temperature, as well as operating mode influence on the performance obtained. An Analysis of Variance shows how outdoor airflow has a key role in the performance of the systems; whereas entering outdoor air temperature determines cooling capacities. Improvements introduced by larger heat exchange areas compensate with their corresponding smaller cross sections, which hinder water – air distribution on the exhaust air side of the heat exchanger. Finally, these small devices achieve cooling capacities of up to 800 W, being able to partly support ventilation load and achieving around 50% of energy saving in ventilation cooling. -- Highlights: ► Two indirect evaporative cooler prototypes are experimentally characterised. ► Evaporative cooling improves heat recovery. ► Influence on performance of different heat exchange area and cross section is studied. ► Larger cross section favours evaporative cooling process. ► Effect of smaller heat exchange area is compensated by that of larger cross section

Experimental investigation of water sprayed finned heat exchanger tube bundles

International Nuclear Information System (INIS)

Sommer, A.

1987-07-01

Experimental investigations have been made to study the performance of two finned tube-bundle heat exchangers (FORGO type) when wetted by water sprays. The heat exchangers are designed to cool water in a dry cooling tower. The test-elements had a frontal area of 1 m 2 . The water sprays were created by 20 nozzles, 200 mm in front of the heat exchangers. Air velocities at the inlet of the coolers were in the range 0,8 m/s to 12 m/s and initial temperature differences ITD reached 45 degrees C. The test facility was designed to determine the combined latent and sensible heat fluxes in the wetted heat exchanger, the airside pressure drop and the air humidity and temperature at the exchanger inlet and outlet, and to measure the weight of the water wetting the cooler's surface. The sprayed test elements were investigated in different positions, but most of the experiments were carried out in the position with the fins horizontal

Thermal energy analysis of a lime production process: Rotary kiln, preheater and cooler

International Nuclear Information System (INIS)

Shahin, Hamed; Hassanpour, Saeid; Saboonchi, Ahmad

2016-01-01

Highlights: • The integrated model for lime production unit which includes cooler, preheater and rotary kiln is developed. • The effect of residence time in each section on efficiency is investigated. • Influence of material feed rate and excess air on specific fuel consumption is analyzed. • The significant effect of particle size on efficiency and specific fuel consumption is shown. - Abstract: In this paper, thermal energy analysis of three zones of a lime production process, which are preheater, rotary kiln and cooler, is performed. In order to perform a proper quantitative estimation, the system was modeled using energy balance equations including coupled heat transfer and chemical reaction mechanisms. A mathematical model was developed, and consequently, the thermal and chemical behavior of limestone was investigated. The model was verified using empirical data. After model confirmation, the variation of Specific Fuel Consumption (SFC) versus production rate was predicted and the optimum condition was determined. Subsequently, fuel consumption was calculated regarding to altered residence time inside each zone of lime production process, for a constant output. Results indicate that increasing the residence time inside each zone of lime production process, will enhance thermal efficiency and saves fuel consumption. Relative enhancement will be the same for different sizes of limestone. It was found that a 10-min increase in material residence time inside the preheater or rotary kiln can reduce fuel consumption by around two percent. Whereas, a 5-min increase in material residence time inside the cooler would be enough to obtain a similar result. Finally, the ratio of air-to-fuel and production rate are changed in such a way that the same product is achieved. The model predicts that lowering excess air from 15% to 10% leads to a 2.5% reduction of Specific Fuel Consumption (SFC).

Microbiological problems and biofilms associated with Mycobacterium chimaera in heater-cooler units used for cardiopulmonary bypass.

Science.gov (United States)

Walker, J; Moore, G; Collins, S; Parks, S; Garvey, M I; Lamagni, T; Smith, G; Dawkin, L; Goldenberg, S; Chand, M

2017-07-01

The role of heater-cooler units (HCUs) in the transmission of Mycobacterium chimaera during open heart surgery has been recognized since 2013. Subsequent investigations uncovered a remarkable global outbreak reflecting the wide distribution of implicated devices. HCUs are an essential component of cardiopulmonary bypass operations and their withdrawal would severely affect capacity for life-saving cardiac surgery. However, studies have demonstrated that many HCUs are contaminated with a wide range of micro-organisms, including M. chimaera and complex biofilms. Whole genome sequencing of M. chimaera isolates recovered from one manufacturer's HCUs, worldwide, has demonstrated a high level of genetic similarity, for which the most plausible hypothesis is a point source contamination of the devices. Dissemination of bioaerosols through breaches in the HCU water tanks is the most likely route of transmission and airborne bacteria have been shown to have reached the surgical field even with the use of ultraclean theatre ventilation. Controlling the microbiological quality of the water circulating in HCUs and reducing biofilm formation has been a major challenge for many hospitals. However, enhanced decontamination strategies have been recommended by manufacturers, and, although they are not always effective in eradicating M. chimaera from HCUs, UK hospitals have not reported any new cases of M. chimaera infection since implementing these mitigation strategies. Water safety groups in hospitals should be aware that water in medical devices such as HCUs may act as a vector in the transmission of potentially fatal water-borne infections. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

SAFARI engineering model 50 mK cooler

Science.gov (United States)

Duband, L.; Duval, J. M.; Luchier, N.

2014-11-01

SAFARI is an infrared instrument developed by a European based consortium to be flown in SPICA, a Japanese led mission. The SAFARI detectors are transition edge sensors (TES) and require temperatures down to 50 mK for their operation. For that purpose we have developed a hybrid architecture based on the combination of a 300 mK sorption stage and a small adiabatic demagnetization stage. An engineering model has been designed to provide net heat lifts of 0.4 and 14 μW respectively at 50 and 300 mK, with an overall cycle duration of 48 h and a duty cycle objective of over 75%. The cooler is self-contained, fits in a volume of 156 × 312 × 182 mm and is expected to weigh 5.1 kg. It has been designed to withstand static loads of 120 g and a random vibration level of 21 g RMS.

Design of passive coolers for light-emitting diode lamps using topology optimisation

DEFF Research Database (Denmark)

Alexandersen, Joe; Sigmund, Ole; Meyer, Knud Erik

2018-01-01

Topology optimised designs for passive cooling of light-emitting diode (LED) lamps are investigated through extensive numerical parameter studies. The designs are optimised for either horizontal or vertical orientations and are compared to a lattice-fin design as well as a simple parameter......, while maintaining low sensitivity to orientation. Furthermore, they exhibit several defining features and provide insight and general guidelines for the design of passive coolers for LED lamps....

Performance improvement of a hybrid air conditioning system using the indirect evaporative cooler with internal baffles as a pre-cooling unit

Directory of Open Access Journals (Sweden)

A.E. Kabeel

2017-12-01

Full Text Available In the present paper, the effects of the indirect evaporative cooler with internal baffle on the performance of the hybrid air conditioning system are numerically investigated. The hybrid air conditioning system contains two indirect evaporative coolers with internal baffle, one is utilized to pre-cool the air inlet to the desiccant wheel and the other is utilized to pre-cool the supply air inlet to the room. The effects of the inlet conditions of the process and reactivation air and working air ratio on the thermal performance of the hybrid air conditioning system have been analyzed. The results of this study show that in the hybrid air conditioning system for using the indirect evaporative cooler with internal baffle as a pre-cooling unit, the supply air temperature reduced by 21% and the coefficient of performance improved by 71% as compared to previous designs of the hybrid air conditioning system at the same inlet conditions. For increasing process air inlet temperature from 25 °C to 45 °C, supply air temperature increases from 12.7 °C to 14.2 °C, thermal COP increases from 1.87 to 2.84, and supply air relative humidity increases from 76.7% to 77.4%. Also, for increasing the reactivation air inlet temperature from 70 °C to 110 °C, supply air temperature dropped from 15.9 °C to 10.9 °C, supply air relative humidity dropped from 82.7% to 71.8%, and thermal COP dropped from 4.5 to 1.7. The recommended optimal air working ratio in the indirect evaporative cooler with internal baffle should be 0.15. Keywords: Desiccant material, Solar air collector, Evaporative cooler, Internal baffles, Air conditioning

Reemergence of Mycobacterium chimaera in Heater-Cooler Units despite Intensified Cleaning and Disinfection Protocol.

Science.gov (United States)

Schreiber, Peter W; Kuster, Stefan P; Hasse, Barbara; Bayard, Cornelia; Rüegg, Christian; Kohler, Philipp; Keller, Peter M; Bloemberg, Guido V; Maisano, Francesco; Bettex, Dominique; Halbe, Maximilian; Sommerstein, Rami; Sax, Hugo

2016-10-01

Invasive Mycobacterium chimaera infections after open-heart surgery have been reported internationally. These devastating infections result from aerosols generated by contaminated heater-cooler units used with extracorporeal circulation during surgery. Despite intensified cleaning and disinfection, surveillance samples from factory-new units acquired during 2014 grew nontuberculous mycobacteria after a median of 174 days.

Accelerator studies at cooler rings TARN and TARN II

International Nuclear Information System (INIS)

Katayama, Takeshi.

1992-07-01

Two ion cooler rings, TARN and TARN II were constructed and operated from 1975 to 1992 at the Institute for Nuclear Study, Univ. of Tokyo, for mainly accelerator studies concerning the beam accumulation, acceleration and cooling. The main subjects performed in these facilities were; 1) beam stacking in transverse and longitudinal phase spaces, 2) stochastic momentum cooling, 3) electron cooling, 4) synchrotron acceleration and 5) slow beam extraction. In the present paper, typical experimental results on these subjects, arc described as well as the basic physical idea underlying these experimental results. The technical details are out of scope of the present paper. They can be found in the other papers refered in the concerned section in the text. (author)

LOREF: Air cooler optimisation with reduction of ice and frost formation - Optimisation of lamella air-coolers/evaporators of air/water heat pumps - Part 1: theoretical and experimental research; LOREF: Luftkuehler-Optimierung mit Reduktion von Eis- und Frostbildung - Optimierung des Lamellenluftkuehlers/Verdampfers von Luft/Wasser-Waermepumpen - Teil 1: theoretische und experimentelle Untersuchungen

Energy Technology Data Exchange (ETDEWEB)

Berlinger, L.; Imholz, M.; Albert, M.; Wellig, B.; Hilfiker, K.

2008-04-15

The use of air/water heat pumps for heating of houses is progressively increasing. It is to be expected that the average coefficient of performance (COP) can be improved substantially over the next decade. Its success will depend on controlling and reducing the formation of frost and ice which reduce the air flow and the heat and mass transfer in the fin tube evaporator. In the LOREF research project a mathematical-physical simulation program has been developed which permits to calculate the formation of condensate, ice and frost and also the pressure loss of the air as a function of space and time at any condition of the ambient air. The theoretical results have been validated by numerous experiments in which the air temperature and humidity, the temperature difference and the air velocity have been systematically varied. Particular emphasis has been given to the geometries of the fin tube evaporator. Several fin partitions along the cooler have been investigated. Using the simulation program the evaporator of a commercial heat pump was optimized and experimentally compared to the original evaporator. The resulting seasonal performance factors were nearly equal what confirms the small differences obtained by simulations. Nevertheless, the optimized evaporator features advantages in respect of the defrosting with ambient air because of its bigger fin spacing and the resulting decrease in pressure drop. The results of the LOREF research project are now the basis for the overall optimization of air/water heat pumps. (author)

Indirect evaporative coolers with enhanced heat transfer

Science.gov (United States)

Kozubal, Eric; Woods, Jason; Judkoff, Ron

2015-09-22

A separator plate assembly for use in an indirect evaporative cooler (IEC) with an air-to-air heat exchanger. The assembly includes a separator plate with a first surface defining a dry channel and a second surface defining a wet channel. The assembly includes heat transfer enhancements provided on the first surface for increasing heat transfer rates. The heat transfer enhancements may include slit fins with bodies extending outward from the first surface of separator plate or may take other forms including vortex generators, offset strip fins, and wavy fins. In slit fin implementations, the separator plate has holes proximate to each of the slit fins, and the separator plate assembly may include a sealing layer applied to the second surface of the separator plate to block air flow through the holes. The sealing layer can be a thickness of adhesive, and a layer of wicking material is applied to the adhesive.

Efficiency of the Fermilab Electron Cooler's Collector

CERN Document Server

Prost, L R

2005-01-01

The newly installed high-energy Recycler Electron Cooling system (REC) at Fermilab will work at an electron energy of 4.34 MeV and a DC beam current of 0.5 A in an energy recovery scheme. For reliable operation of the system, the relative beam current loss must be maintained to levels < 3.e-5. Experiments have shown that the loss is determined by the performance of the electron beam collector, which must retain secondary electrons generated by the primary beam hitting its walls. As a part of the Electron cooling project, the efficiency of the collector for the REC was optimized, both with dedicated test bench experiments and on two versions of the cooler prototype. We find that to achieve the required relative current loss, an axially-symmetric collector must be immersed in a transverse magnetic field with certain strength and gradient prescriptions. Collector efficiencies in various magnetic field configurations, including without a transverse field on the collector, are presented and discussed

Numerical modeling of the thermoelectric cooler with a complementary equation for heat circulation in air gaps

Science.gov (United States)

Fang, En; Wu, Xiaojie; Yu, Yuesen; Xiu, Junrui

2017-03-01

In this paper, a numerical model is developed by combining thermodynamics with heat transfer theory. Taking inner and external multi-irreversibility into account, it is with a complementary equation for heat circulation in air gaps of a steady cooling system with commercial thermoelectric modules operating in refrigeration mode. With two modes concerned, the equation presents the heat flowing through air gaps which forms heat circulations between both sides of thermoelectric coolers (TECs). In numerical modelling, a TEC is separated as two temperature controlled constant heat flux reservoirs in a thermal resistance network. In order to obtain the parameter values, an experimental apparatus with a commercial thermoelectric cooler was built to characterize the performance of a TEC with heat source and sink assembly. At constant power dissipation, steady temperatures of heat source and both sides of the thermoelectric cooler were compared with those in a standard numerical model. The method displayed that the relationship between Φf and the ratio Φ_{c}'/Φ_{c} was linear as expected. Then, for verifying the accuracy of proposed numerical model, the data in another system were recorded. It is evident that the experimental results are in good agreement with simulation(proposed model) data at different heat transfer rates. The error is small and mainly results from the instabilities of thermal resistances with temperature change and heat flux, heat loss of the device vertical surfaces and measurements.

Forecast of winter performances of dry coolers with fin tubes; Voorspelling winterprestaties droge koelers met ribbenbuizen

Energy Technology Data Exchange (ETDEWEB)

Yu, Bing [Shanghai DFYH Tech Services Co. Ltd, Shanghai (China); Wang, Xichun [Arup, Shanghai (China); Luscuere, P.G. [Faculteit Bouwkunde, Technische Universiteit Delft, Delft (Netherlands)

2011-01-15

A mathematical model is presented to predict the behaviors of dry coolers by considering the condensing and frosting. It employs one-dimensional transient finite differential formulation with variation of the frost density and thickness. The model is validated by experiments and predicts the heat transfer performance with an accuracy within 2.19%. It is helpful for the operation of dry coolers in winter. [Dutch] In dit artikel wordt een wiskundig model gepresenteerd, waarmee voortschrijdende condens- en ijsvorming op warmteoverdrachtsoppervlakken kunnen worden voorspeld aan de hand van de gevormde condens- en ijslagen. Het model maakt gebruik van eendimensionale transiente formuleringen op basis van een techniek voor lokale uitmiddeling. Hierbij wordt rekening gehouden met de varierende dichtheid en dikte van de ijslaag. Validatie van het model heeft plaatsgevonden door de resultaten te vergelijken met proefgegevens van de fabrikant van de droge koeler.

Development of the performance of an alpha-type heat engine by using elbow-bend transposed-fluids heat exchanger as a heater and a cooler

Energy Technology Data Exchange (ETDEWEB)

El-Ehwany, A.A.; Hennes, G.M. [Mechanical Power Department, Faculty of Engineering, Ain Shams University, 11566 Cairo (Egypt); Eid, E.I. [Mechanical Department, Faculty of Industrial Education, Suez Canal University, 43515 Suez (Egypt); El-Kenany, E.A. [Technological Development Department, Technological Studies Academy, Workers University, Tanta (Egypt)

2011-02-15

In this work, elbow-bend heat exchangers were suggested to be used as a heater and a cooler in an alpha-type Stirling engine. Elbow-bend heat exchanger is a bank of tubes arranged in a quadrant either in line or staggered with different normal and parallel pitches. Eight of such heat exchangers having different dimensions were tested experimentally for steady flow (in a previous work by the same authors). The experimental results were correlated for heat transfer and pressure drop. In the present work, an alpha-Stirling engine with twin parallel cylinders on a common crankcase was suggested to use elbow-bend heat exchangers as a heater and a cooler. In the heater, the flue gases flow inside the tubes and the working gas fluctuates about the heater tubes. In the cooler, the coolant flows inside the cooler tubes and the gas flows about the cooler tubes. A computer program in the form of a spread sheet was prepared to solve numerically the engine cycle in the vision of Schmidt theory. Upon calculations, the most suitable stroke/bore ratio, phase angle and speed were found out for nitrogen as a working gas. In a comparison among the proposed engine and practical ones by the literature, it was found that; the proposed engine delivers about 13% more power per cc per {delta}T than those by the literature at high thermal efficiency level. (author)

Reemergence of Mycobacterium chimaera in Heater–Cooler Units despite Intensified Cleaning and Disinfection Protocol

Science.gov (United States)

Schreiber, Peter W.; Kuster, Stefan P.; Hasse, Barbara; Bayard, Cornelia; Rüegg, Christian; Kohler, Philipp; Keller, Peter M.; Bloemberg, Guido V.; Maisano, Francesco; Bettex, Dominique; Halbe, Maximilian; Sommerstein, Rami

2016-01-01

Invasive Mycobacterium chimaera infections after open-heart surgery have been reported internationally. These devastating infections result from aerosols generated by contaminated heater–cooler units used with extracorporeal circulation during surgery. Despite intensified cleaning and disinfection, surveillance samples from factory-new units acquired during 2014 grew nontuberculous mycobacteria after a median of 174 days. PMID:27649345

Commissioning of HIRFL-CSR and its Electron Coolers

International Nuclear Information System (INIS)

Yang Xiaodong; Zhan Wenlong; Xia Jiawen; Zhao Hongwei; Yuan Youjin; Song Mingtao; Li Jie; Mao Lijun; Lu Wang; Wang Zhixue; Parkhomchuk, Vasily

2006-01-01

The brief achievements of HIRFL-CSR commissioning and the achieved parameters of its coolers were presented. With the help of electron cooling code, the cooling time of ion beam were extensive simulated in various parameters of the ion beam in the HIRFL-CSR electron cooling storage rings respectively, such as ion beam energy, initial transverse emittance, and momentum spread. The influence of the machine lattice parameters-betatron function, and dispersion function on the cooling time was investigated. The parameters of electron beam and cooling devices were taken into account, such as effective cooling length, magnetic field strength and its parallelism in cooling section, electron beam size and density. As a result, the lattice parameters of HIRFL-CSR were optimal for electron cooling, and the parameters of electron beam can be optimized according to the parameters of heavy ion beam

Fabrication of a Micro Cooler using Thermoelectric Thin Film

International Nuclear Information System (INIS)

Han, S. W.; Choi, H. J.; Kim, D. H.; Kim, W. J.; Kim, B. I.; Kim, K. M.

2007-01-01

In general a ThermoElectric Cooler (TEC) consists of a series of P type and N type thermoelectric materials sandwiched between two wafers. When a DC current passes through these materials, three different effects take place; Peltier effect, Joule heating effect and heat transfer by conduction due to temperature difference between hot and cold plates. In this study we have developed a micro TEC using Bi2Te3 (N type) and Bi0.5Sb1.5Te3 (P type) thin films. In order to improve that performance of a micro TEC, we made 10 um height TE legs using special PR only for lift-off. We measured COP (coefficient of performance) and temperature difference between hot and cold connectors with current

Regulatory analysis for the resolution of Generic Issue 130: Essential service water system failures at multi-unit sites

International Nuclear Information System (INIS)

Leung, V.; Basdekas, D.; Mazetis, G.

1991-06-01

The essential service water system (ESWS) is required to provide cooling in nuclear power plants during normal operation and accident conditions. The ESWS typically supports component cooling water heat exchangers, containment spray heat exchangers, high-pressure injection pump oil coolers, emergency diesel generators, and auxiliary building ventilation coolers. Failure of the ESWS function could lead to severe consequences. This report presents the regulatory analysis for GI-130, ''Essential Service Water System Failures at Multi-Unit Sites.'' The risk reduction estimates, cost/benefit analyses, and other insights gained during this effort have shown that implementation of the recommendations will significantly reduce risk and that these improvements are warranted in accordance with the backfit rule, 10 CFR 50.109(a)(3). 19 refs., 16 tabs

75 FR 55067 - Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In Freezers

Science.gov (United States)

2010-09-09

... submitted using any of the following methods: 1. Federal eRulemaking Portal: http://www.regulations.gov... Proposal III. Discussion A. Overall Issues 1. Definition of Walk-In Cooler or Freezer: Temperature Limit 2.... Description and Estimated Number of Small Entities Regulated 4. Description and Estimate of Compliance...

Design and development of a four-cell sorption compressor based J-T cooler using R134a as working fluid

Energy Technology Data Exchange (ETDEWEB)

Mehta, R. N. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai - 400076, India and Government Engineering College Bharuch, Gujarat - 392002 (India); Bapat, S. L.; Atrey, M. D. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai - 400076 (India)

2014-01-29

The need of a cooler with no electromagnetic interference and practically zero vibration has led to sorption compressor based Joule-Thomson (J-T) coolers. These are useful for sophisticated electronic, ground based and space borne systems. In a Sorption compressor, adsorbed gases are desorbed into a confined volume by raising temperature of the sorption bed resulting in an increase in pressure of the liberated gas. In order to have the system (compressor) functioning on a continuous basis, with almost a constant gas flow rate, multiple cells are used with the adaptation of Temperature Swing Adsorption (TSA) process. As the mass of the desorbed gas dictates the compressor throughput, a combination of sorbent material with high adsorption capacity for a chosen gas or gas mixture has to be selected for efficient operation of the compressor. Commercially available (coconut-shell base) activated carbon has been selected for the present application. The characterization study for variation of discharge pressure is used to design the Four-cell sorption compressor based cryocooler with a desired output. Apart from compressor, the system includes a) After cooler b) Return gas heat exchanger c) capillary tube as the J-T expansion device and d) Evaporator.

Optimization of a microfluidic electrophoretic immunoassay using a Peltier cooler.

Science.gov (United States)

Mukhitov, Nikita; Yi, Lian; Schrell, Adrian M; Roper, Michael G

2014-11-07

Successful analysis of electrophoretic affinity assays depends strongly on the preservation of the affinity complex during separations. Elevated separation temperatures due to Joule heating promotes complex dissociation leading to a reduction in sensitivity. Affinity assays performed in glass microfluidic devices may be especially prone to this problem due to poor heat dissipation due to the low thermal conductivity of glass and the large amount of bulk material surrounding separation channels. To address this limitation, a method to cool a glass microfluidic chip for performing an affinity assay for insulin was achieved by a Peltier cooler localized over the separation channel. The Peltier cooler allowed for rapid stabilization of temperatures, with 21°C the lowest temperature that was possible to use without producing detrimental thermal gradients throughout the device. The introduction of cooling improved the preservation of the affinity complex, with even passive cooling of the separation channel improving the amount of complex observed by 2-fold. Additionally, the capability to thermostabilize the separation channel allowed for utilization of higher separation voltages than what was possible without temperature control. Kinetic CE analysis was utilized as a diagnostic of the affinity assay and indicated that optimal conditions were at the highest separation voltage, 6 kV, and the lowest separation temperature, 21°C, leading to 3.4% dissociation of the complex peak during the separation. These optimum conditions were used to generate a calibration curve and produced 1 nM limits of detection, representing a 10-fold improvement over non-thermostated conditions. This methodology of cooling glass microfluidic devices for performing robust and high sensitivity affinity assays on microfluidic systems should be amenable in a number of applications. Copyright © 2014 Elsevier B.V. All rights reserved.

75 FR 186 - Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In Freezers

Science.gov (United States)

2010-01-04

.... Measuring the U Value of glass 10. Floor R Value 11. Electrical Duty Cycle 12. Normalization Factor 13... coolers and freezers. The walk-in envelope includes, but may not be limited to, walls, floor, ceiling... performance (this process is also known as ``aging''). This diffusion process causes foam to lose insulating...

Studying the operational regimes of air-radiator coolers at the Bilibin NPP

International Nuclear Information System (INIS)

Gutsev, D.F.; Dembovskij, A.V.; Kuznetsov, R.K.; Lukashenko, Eh.M.; Morozov, S.K.; Soldatov, G.E.

1985-01-01

Results of experimental and calculational-theoretical studies of operational regimes of airradiator coolers at the Bilibin NPP are set out. For the first time dry fan towers are used there under the Far North conditions. Operational experience of the Forgo cooling towers under the above conditions is given. The mathematical model of monstationary heat transfer in a pipe heat exchanger ribbed with perforated plates is worked out for numerical analysis of the tower operational regimes. The results of studies point out the ways for improvement of the cooling towers and their operational conditions

A radio frequency ring electrode cooler for low-energy ion beams

International Nuclear Information System (INIS)

Heinz, S.; Aeystoe, J.; Habs, D.; Hegewisch, S.; Huikari, J.; Nieminen, A.; Rinta-Antila, S.; Schumann, M.; Szerypo, J.

2004-01-01

We are investigating a new concept for ion confinement while buffer-gas-cooling low-energy ion beams. Instead of applying the well-established technique of Radio Frequency Quadrupoles (RFQs) where the ions are transversely confined by a quadratic-pseudo potential we are using a stack of thin ring electrodes supplied by an RF field (RF funnel) which creates a box-shaped potential well. In Monte Carlo simulations we have investigated the transmission behavior and cooling performance of the RF funnel. First experimental investigations with ion currents up to 20 nA revealed a promising transmission characteristic which qualifies the RF funnel as high-current cooler

A beam position monitor system for electron cooler in HIRFL-CSR

International Nuclear Information System (INIS)

Li Guohong; Li Jie; Yang Xiaodong; Yan Tailai; Ma Xiaoming

2010-01-01

The efficient electron cooling requires that the ion beam and electron beam are parallel and overlapped. In order to measure the positions of ion beam and electron beam simultaneously, a beam position monitor system is developed for the HIRFL-CSR electron cooler device, which probe consists of four capacitive cylinder linear-cut poles. One can get the both beam positions from the picking up signals of four poles by using Fourier transform (FFT) method. The measurement results show that the beam position monitor system is accurate. This system is suitable for investigating the relation between electron cooling processing and the angle of ion beam and electron beam. (authors)

A comparative study on energetic, exergetic and environmental performance assessments of novel M-Cycle based air coolers for buildings

International Nuclear Information System (INIS)

Caliskan, Hakan; Dincer, Ibrahim; Hepbasli, Arif

2012-01-01

Highlights: ► Applying exergy, environment and sustainability analyses to the three (novel M-Cycle based) air coolers. ► Assessing energy and exergy efficiencies, environmental impact and sustainability. ► Proposing System II (using PV-based electricity) as the most environmentally friendly air cooler. ► Proposing System III (using coal-based electricity) as the most efficient air cooler. - Abstract: In this study, three various novel air coolers based on M-Cycle are evaluated using energy and exergy analyses based efficiency assessments along with environmental impact and sustainability parameters. The M-Cycle systems are considered to cool a building room air while their inlet air parameters are same, but outlet cooled air parameters are different. Systems I and III draw electricity directly taken from an electric grid in the building while System II, which is stand alone system, produces and draws electricity from its solar PV panels. In the energy analysis, wet bulb effectiveness, cooling capacity, Coefficient of Performance (energetic COP) and Primary Energy Ratio (PER) are found. In the exergy analysis, exergy input and output rates, exergy loss rate, exergy destruction rate, Exergetic Coefficient of Performance (COP ex ), Primary Exergy Ratio (PE x R) and exergy efficiency are obtained for six different dead state temperatures changing between 10 °C and 35 °C. Also, sustainability assessments of the systems are obtained using sustainability index (SI) tool for these various dead state temperatures. Finally, environmental assessments of the systems are calculated from their greenhouse gas (GHG) emissions (gCO 2 /kW h) due to their electricity consumptions. Maximum exergy efficiencies and sustainability assessments are found to be 35.13% and 1.5415 for System III and 34.94% and 1.5372 for System II, respectively. GHG emissions of the systems are calculated to be 2119.68 gCO 2 /day, 153.6 gCO 2 /day and 3840 gCO 2 /day for Systems I, II and III

Beam accumulation with the SIS electron cooler

International Nuclear Information System (INIS)

Steck, M.; Groening, L.; Blasche, K.; Franczak, B.; Franzke, B.; Winkler, T.; Parkhomchuk, V.V.

2000-01-01

An electron cooling system has started operation in the heavy ion synchrotron SIS which is used to increase the intensity for highly charged ions. Fast transverse cooling of the hot ion beam after horizontal multiturn injection allows beam accumulation at the injection energy. After optimization of the accumulation process an intensity increase in a synchrotron pulse by more than one order of magnitude has been achieved. For highly charged ions the maximum number of particles has been increased from 1x10 8 to 1x10 9 . For lighter ions intensity limitations have been encountered which are caused by the high phase space density of the cooled ion beam. Momentum spreads in the 10 -4 range and emittances well below 10 π mm mrad have been demonstrated. Recombination losses both in the residual gas and with the free cooler electrons determine the maximum intensity for highly charged ions. Systematic measurements of the recombination rates have been performed providing data for an optimum choice of the charge state. Strong enhancement of the recombination rate with free electrons compared to theoretical calculations of radiative electron capture have been observed

A techno-economic analysis of cost savings for retrofitting industrial aerial coolers with variable frequency drives

International Nuclear Information System (INIS)

Miller, Patrick; Olateju, Babatunde; Kumar, Amit

2012-01-01

Highlights: ► Techno-economic models were developed to assess the retrofitting of aerial coolers. ► The IRR for retrofitting with VFDs exceeds 10% for motor sizes above 20 hp. ► The IRR reaches a maximum of 220% for a cooler with fifty, 250 hp motors. ► The simple payback becomes less than 1 year for motors larger than 120 hp. ► Ambient temperature and location affects the profitability of VFD investment. - Abstract: A techno-economic model was created in order to develop curves that show the typical annual energy savings, rate of return, and payback for retrofitting aerial coolers with variable frequency drives (VFDs) for up to 50 motors, motor sizes from 4 to 186 kW (5–250 hp), and varying climate conditions. The cost savings due to installing a VFD depends on the reduction in energy used, as well as the reduction in power demand, the capital cost of the VFD, installation cost of the VFD, change in operating cost, and cost of electricity. The geographic locations examined in this report were Fort McMurray, Calgary, Vancouver, and Thunder Bay. This study found that the IRR increases rapidly with motor size, becomes greater than 10% at a motor size of approximately 15 kW, and may be as high as 220% (for the case of fifty, 186 kW motors). The IRR is sensitive to the number of fan motors retrofitted with VFDs, however the sensitivity rapidly declines as the number of motors is increased beyond five. The simple payback period becomes less than 1 year and nearly independent of number of motors and motor size for motors larger than 90 kW. Ambient temperature and geographic location affect the profitability of the investment, although the IRR only changes by approximately 4%.

Groundwater heat pump performance improvement with pre-coolers and pump modification: Final report for the 1985-86 SOMED (School of Mines and Energy Development) project year

Energy Technology Data Exchange (ETDEWEB)

Kavanaugh, S.

1986-09-30

Improved performance of groundwater heat pumps can be realized with a more effective and efficient utilization of the thermal properties of shallow groundwater. These systems circulate water from aquifers through water source heat pumps to achieved high efficiencies and capacities. This project concludes that a 10 to 15 percent cooling performance improvement can be realized by pre-cooling the room air with the 55/sup 0/ to 67/sup 0/F groundwater available in large portions of the Southeast. Proper design of these pre-coolers eliminates unnecessary auxiliary energy requirements. The efficiency of the overall system can be further improved with modifications to current methods of water circulation system design. Pressure requirements are minimized by maintaining a low unit inlet pressure (8 psig maximum), removing unnecessary loop restrictions and injection below the water table. Standard submersible water pumps exceed the resulting required size for residential groundwater heat pumps. Simple modifications can be made by the manufacturer to correct this problem. The result is an overall 15 to 40 percent performance improvement over high efficiency air source heat pumps with a simple payback of between 0 to 10 years in most cases.

Water conservation and improved production efficiency using closed-loop evaporative cooling systems

Energy Technology Data Exchange (ETDEWEB)

Marchetta, C. [Niagara Blower Co., Buffalo, NY (United States)

2009-07-01

This paper described wet surface air coolers (WSAC) that can be used in refineries and hydrocarbon processing plants to address water use issues. These closed-loop evaporative cooling systems are a cost-effective technology for both heat transfer and water conservation. WSACs can help deliver required cooling water temperatures and improve plant performance while using water streams currently considered to be unusable with conventional towers and heat exchangers. WSACs are versatile and can provide solutions to water use, water quality, and outlet temperature. The benefits of the WSAC include capital cost savings, reduced system pressures, lower carbon footprint, and the ability to use poor quality water as makeup. Water makeup can be blowdown from other equipment, plant effluent, reclaimed water, produced water, flue gas desulphurization (FGD) wastewater, and even seawater. Units can be manufactured with a wide variety of materials depending on water quality, water treatment, and cycles of concentration. This paper also provided comparisons to other alternative technologies, capital and operating cost savings, and site specific case studies. Two other system designs can accommodate closed-loop heat transfer applications, notably an open tower with a heat exchanger and a dry, air-cooled system. A WSAC system is an efficient and effective heat rejection technology for several reasons. The WSAC cooler or condenser utilizes latent cooling, which is far more efficient than sensible cooling. This means that a WSAC system can cool the same heat load with a smaller footprint than all-dry systems. 6 figs.

Multi-objective optimization design of air distribution of grate cooler by entropy generation minimization and genetic algorithm

International Nuclear Information System (INIS)

Shao, Wei; Cui, Zheng; Cheng, Lin

2016-01-01

Highlights: • A multi-objective optimization model of air distribution of grate cooler by genetic algorithm is proposed. • Pareto Front is obtained and validated by comparing with operating data. • Optimal schemes are compared and selected by engineering background. • Total power consumption after optimization decreases 61.10%. • Thickness of clinker on three grate plates is thinner. - Abstract: The cooling air distributions of grate cooler exercise a great influence on the clinker cooling efficiency and power consumption of cooling fans. A multi-objective optimization model of air distributions of grate cooler with cross-flow heat exchanger analogy is proposed in this paper. Firstly, thermodynamic and flow models of clinker cooling process is carried out. Then based on entropy generation minimization analysis, modified entropy generation numbers caused by heat transfer and pressure drop are chosen as objective functions respectively which optimized by genetic algorithm. The design variables are superficial velocities of air chambers and thicknesses of clinker layers on different grate plates. A set of Pareto optimal solutions which two objectives are optimized simultaneously is achieved. Scattered distributions of design variables resulting in the conflict between two objectives are brought out. The final optimal air distribution and thicknesses of clinker layers are selected from the Pareto optimal solutions based on power consumption of cooling fans minimization and validated by measurements. Compared with actual operating scheme, the total air volumes of optimized schemes decrease 2.4%, total power consumption of cooling fans decreases 61.1% and the outlet temperature of clinker decreases 122.9 °C which shows a remarkable energy-saving effect on energy consumption.

Spin flipping a stored polarized proton beam at the IUCF cooler ring

International Nuclear Information System (INIS)

Phelps, R.A.

1995-01-01

We recently studied the spin flip of a vertically polarized 139 MeV proton beam stored in the IUCF Cooler Ring. We used an rf solenoid to induce a depolarizing resonance in the ring; we flipped the spin by varying the solenoid field's frequency through this resonance. We found a polarization loss after multiple spin flips less than 0.1% per flip; we also found that this loss increased for very slow frequency changes. This spin flip could reduce systematic errors in stored polarization beam experiments by allowing frequent beam polarization reversals during the experiment. copyright 1995 American Institute of Physics

The Next Generation Sky Survey and the Quest for Cooler Brown Dwarfs

OpenAIRE

Kirkpatrick, J. Davy

2002-01-01

The Next Generation Sky Survey (NGSS) is a proposed NASA MIDEX mission to map the entire sky in four infrared bandpasses - 3.5, 4.7, 12, and 23 um. The seven-month mission will use a 50-cm telescope and four-channel imager to survey the sky from a circular orbit above the Earth. Expected sensitivities will be half a million times that of COBE/DIRBE at 3.5 and 4.7 um and a thousand times that of IRAS at 12 and 23 um. NGSS will be particularly sensitive to brown dwarfs cooler than those present...

Interference characterisation of a commercial Joule-Thomson cooler to be used in a SQUID-based heart monitor

NARCIS (Netherlands)

Bangma, M.R.; Bangma, M.R.; Rijpma, A.P.; de Vries, E.; Reincke, H.A.; Holland, Herman J.; ter Brake, Hermanus J.M.; Rogalla, Horst

2001-01-01

At the University of Twente, a foetal heart monitor based on a high-TC SQUID magnetometer system is under development. The purpose of this system is to measure a foetal heart signal in a clinical environment. For cooling a first demonstrator version, a closed-cycle Joule–Thomson cooler from APD

Optimal Integration of Cascade Thermoelectric Cooler into Electronic Housing: Experimental Approach

Science.gov (United States)

Semeniuk, V.; Protsenko, D.

2018-06-01

The problem of the optimal integration of thermoelectrically cooled optoelectronic components into an electronic housing is studied with the emphasis on practical implementation. The lines of 2-stage and 3-stage thermoelectric coolers (TECs) compatible with TO8 housing have been developed, and their parameters are measured in a wide range of heat sink temperatures. The TECs are optimized to receive a temperature difference of 100-110 K under a heat load from 70 mW to 100 mW with minimal power consumption. To fit into a standard housing interior, all the TECs have the same overall dimensions, regardless of the number of stages. Details of the TEC configurations and their performance characteristics are presented and discussed.

A water-cooling solution for PC-racks of the LHC experiments

CERN Document Server

Vannerem, P

2004-01-01

With ever increasing power consumption and heat dissipation of todays CPUs, cooling of rack-mounted PCs is an issue for the future online farms of the LHC experiments. In order to investigate the viability of a water-cooling solution, a prototype PC-farm rack has been equipped with a commercially available retrofitted heat exchanger. The project has been carried out as a collaboration of the four LHC experiments and the PH-ESS group . This note reports on the results of a series of cooling and power measurements of the prototype rack with configurations of 30 to 48 PCs. The cooling performance of the rack-cooler is found to be adequate; it extracts the heat dissipated by the CPUs efficiently into the cooling water. Hence, the closed PC rack transfers almost no heat into the room. The measurements and the failure tests show that the rack-cooler concept is a viable solution for the future PC farms of the LHC experiments.

Experiments in a natural circulation loop with supercritical water at low powers

International Nuclear Information System (INIS)

Pilkhwal, D.S.; Sharma, Manish; Jana, S.S.; Vijayan, P.K.

2013-05-01

Earlier, 1/2 ″ uniform diameter Supercritical Pressure Natural Circulation Loop (SPNL) was set-up in hall-7, BARC for carrying out experiments related to supercritical fluids. The loop is a rectangular loop having two heaters and two coolers. Experiments were carried out with CO 2 under supercritical conditions for various pressures and different combinations of heater and cooler orientations. Since, the design conditions are more severe for supercritical water (SCW) experiments, the loop was modified for SCW by installing new test sections, pressurizer and power supply for operation with supercritical water. Experimental data were generated on steady state, heat transfer and stability under natural circulation conditions for the horizontal heater and horizontal cooler (HHHC) orientation with SCW up to a heater power of 8.5 kW. The flow rate data and instability data were compared with the predictions of in-house developed 1-D code NOLSTA, which showed reasonable agreement. The heat transfer coefficient data were also compared with the predictions of various correlations exhibit peak at bulk temperature lower than that obtained in the experiments. Most of these correlations predicted experimental data well in the pseudo-critical region. However, all correlations are matching well with experimental data beyond the pseudo-critical region. The details of the experimental facility, Experiments carried out and the results presented in this report. (author)

Growth Rate Potential of Juvenile Sockeye Salmon in Warmer and Cooler Years on the Eastern Bering Sea Shelf

Directory of Open Access Journals (Sweden)

Edward V. Farley

2009-01-01

Full Text Available A spatially explicit bioenergetics model was used to predict juvenile sockeye salmon Oncorhynchus nerka growth rate potential (GRP on the eastern Bering Sea shelf during years with cooler and warmer spring sea surface temperatures (SSTs. Annual averages of juvenile sockeye salmon GRP were generally lower among years with cooler SSTs and generally higher in offshore than nearshore regions of the eastern Bering Sea shelf during years with warmer SSTs. Juvenile sockeye salmon distribution was significantly (P<.05 related to GRP and their prey densities were positively related to spring SST (P<.05. Juvenile sockeye salmon GRP was more sensitive to changes in prey density and observed SSTs during years when spring SSTs were warmer (2002, 2003, and 2005. Our results suggest that the pelagic productivity on the eastern Bering Sea shelf was higher during years with warmer spring SSTs and highlight the importance of bottom-up control on the eastern Bering Sea ecosystem.

Development of a new RFQ beam cooler and buncher for the CANREB project at TRIUMF

Energy Technology Data Exchange (ETDEWEB)

Barquest, B.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Bale, J.C.; Dilling, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); UBC Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Gwinner, G. [University of Manitoba, Department of Physics and Astronomy, Allen Building, Winnipeg, MB R3T 2N2 (Canada); Kanungo, R. [Saint Mary’s University, Astronomy and Physics Department, 923 Robie Street, Halifax, NS B3H 3C3 (Canada); Krücken, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); UBC Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Pearson, M.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada)

2016-06-01

A new radiofrequency quadrupole (RFQ) based ion beam cooler and buncher is under development for the CANadian Rare-isotope facility with Electron Beam ion source (CANREB) project at TRIUMF. The CANREB project requires an RFQ buncher that will efficiently accept continuous beams of rare isotopes from either the Advanced Rare IsotopE Laboratory (ARIEL) or Isotope Separator and ACcelerator (ISAC) target by way of a high resolution magnetic spectrometer, with energies up to 60 keV and deliver bunched beams to an electron beam ion source (EBIS) for charge breeding. The energy of the bunched beam delivered to the EBIS will be adjustable to match the requirements of the existing post acceleration infrastructure. The CANREB RFQ incorporates design considerations to facilitate ease of use over a wide range of ion masses, and is intended to accommodate incident beam rates as high as 10{sup 8} pps, delivering beam bunches at 100 Hz. An overview of the CANREB RFQ design concept will be presented, informed by results from both ion optical simulations as well as commissioning efforts with other beam cooler and buncher devices. Simulation results indicate that the design is well suited to deliver high quality bunched beams with high efficiency with as many as 10{sup 6} ions per bunch.

Geometric Optimization of Thermo-electric Coolers Using Simulated Annealing

International Nuclear Information System (INIS)

Khanh, D V K; Vasant, P M; Elamvazuthi, I; Dieu, V N

2015-01-01

The field of thermo-electric coolers (TECs) has grown drastically in recent years. In an extreme environment as thermal energy and gas drilling operations, TEC is an effective cooling mechanism for instrument. However, limitations such as the relatively low energy conversion efficiency and ability to dissipate only a limited amount of heat flux may seriously damage the lifetime and performance of the instrument. Until now, many researches were conducted to expand the efficiency of TECs. The material parameters are the most significant, but they are restricted by currently available materials and module fabricating technologies. Therefore, the main objective of finding the optimal TECs design is to define a set of design parameters. In this paper, a new method of optimizing the dimension of TECs using simulated annealing (SA), to maximize the rate of refrigeration (ROR) was proposed. Equality constraint and inequality constraint were taken into consideration. This work reveals that SA shows better performance than Cheng's work. (paper)

Consideration of Relativistic Dynamics in High-Energy Electron Coolers

CERN Document Server

Bruhwiler, David L

2005-01-01

A proposed electron cooler for RHIC would use ~55 MeV electrons to cool fully-ionized 100 GeV/nucleon gold ions.* At two locations in the collider ring, the electrons and ions will co-propagate for ~13 m, with velocities close to c and gamma>100. To lowest-order, one can Lorentz transform all physical quantities into the beam frame and calculate the dynamical friction forces assuming a nonrelativisitc, electrostatic plasma. However, we show that nonlinear space charge forces of the bunched electron beam on the ions must be calculated relativistically, because an electrostatic beam-frame calculation is not valid for such short interaction times. The validity of nonrelativistic friction force calculations must also be considered. Further, the transverse thermal velocities of the high-charge (~20 nC) electron bunch are large enough that some electrons have marginally relativistic velocities, even in the beam frame. Hence, we consider relativistic binary collisions – treating the model problem of ...

Thermoelectric mini cooler coupled with micro thermosiphon for CPU cooling system

International Nuclear Information System (INIS)

Liu, Di; Zhao, Fu-Yun; Yang, Hong-Xing; Tang, Guang-Fa

2015-01-01

In the present study, a thermoelectric mini cooler coupling with a micro thermosiphon cooling system has been proposed for the purpose of CPU cooling. A mathematical model of heat transfer, depending on one-dimensional treatment of thermal and electric power, is firstly established for the thermoelectric module. Analytical results demonstrate the relationship between the maximal COP (Coefficient of Performance) and Q c with the figure of merit. Full-scale experiments have been conducted to investigate the effect of thermoelectric operating voltage, power input of heat source, and thermoelectric module number on the performance of the cooling system. Experimental results indicated that the cooling production increases with promotion of thermoelectric operating voltage. Surface temperature of CPU heat source linearly increases with increasing of power input, and its maximum value reached 70 °C as the prototype CPU power input was equivalent to 84 W. Insulation between air and heat source surface can prevent the condensate water due to low surface temperature. In addition, thermal performance of this cooling system could be enhanced when the total dimension of thermoelectric module matched well with the dimension of CPU. This research could benefit the design of thermal dissipation of electronic chips and CPU units. - Highlights: • A cooling system coupled with thermoelectric module and loop thermosiphon is developed. • Thermoelectric module coupled with loop thermosiphon can achieve high heat-transfer efficiency. • A mathematical model of thermoelectric cooling is built. • An analysis of modeling results for design and experimental data are presented. • Influence of power input and operating voltage on the cooling system are researched

Water management of HWP - Hazira

International Nuclear Information System (INIS)

Nagar, A.K.

2008-01-01

Water is a precious gift of nature to the mankind and it is vital for living beings and industries. It may become a scarce resource, if proper measures are not adopted timely to conserve the same. Water Management with measures taken for water, energy conservation and effluent reduction at HWP - Hazira are described in the present paper. System details of pre-treatment, cooling water, steam, boiler, effluent etc. pertaining to HWP-Hazira are described. Cooling water treatment adopted in HWP-HAZIRA is operating at 3-4 concentration cycles. Treatment is found to be satisfactory as revealed by the absence of scaling or corrosion induced by microbial fouling in coolers, heat exchangers etc. due to observations made during the last ATR. The cooling water treatment adopted and followed by KRIBHCO is also described. KRIBHCO is operating their cooling water system at a cycle of concentration of 7-8 to conserve water and chemicals. (author)

Interference characterisation of a commercial Joule-Thomson cooler to be used in a SQUID-based foetal heart monitor

NARCIS (Netherlands)

Bangma, M.R.; Rijpma, A.P.; Vries, de E.; Reincke, H.A.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

2001-01-01

At the University of Twente, a fetal heart monitor based on a high-TC SQUID magnetometer system is under development. The purpose of this system is to measure a fetal heart signal in a clin. environment. For cooling a first demonstrator version, a closed-cycle Joule-Thomson cooler from APD

Analysis of helium purification system capability during water ingress accident in RDE

Science.gov (United States)

Sriyono; Kusmastuti, Rahayu; Bakhri, Syaiful; Sunaryo, Geni Rina

2018-02-01

The water ingress accident caused by steam generator tube rupture (SGTR) in RDE (Experimental Power Reactor) must be anticipated. During the accident, steam from secondary system diffused and mixed with helium gas in the primary coolant. To avoid graphite corrosion in the core, steam will be removed by Helium purification system (HPS). There are two trains in HPS, first train for normal operation and the second for the regeneration and accident. The second train is responsible to clean the coolant during accident condition. The second train is equipped with additional component, i.e. water cooler, post accident blower, and water separator to remove this mixture gas. During water ingress, the water release from rupture tube is mixed with helium gas. The water cooler acts as a steam condenser, where the steam will be separated by water separator from the helium gas. This paper analyses capability of HPS during water ingress accident. The goal of the research is to determine the time consumed by HPS to remove the total amount of water ingress. The method used is modelling and simulation of the HPS by using ChemCAD software. The BDBA and DBA scenarios will be simulated. In BDBA scenario, up to 110 kg of water is assumed to infiltrate to primary coolant while DBA is up to 35 kg. By using ChemCAD simulation, the second train will purify steam ingress maximum in 0.5 hours. The HPS of RDE has a capability to anticipate the water ingress accident.

Diagnosis of Catalyst Cooler and Riser in RFCC using Sealed gamma-ray Source

International Nuclear Information System (INIS)

Kim, Jin Seop; Kim, Jong Bum; Jung, Sung Hee; Kim, Jae Ho

2005-12-01

With a quantitative growth of the petroleum industry, a lot of budget are spent for the maintenance and repairs of facilities related to the process annually. Among them, the RFCC(residual fluid catalytic cracking) is a highly value-added unit which converts gas oil and heavier streams to lighter, more valuable products such as propylene, gasoline by an injection of atmospheric residue into the fluided catalyst. In this study, field experiments were performed to analyze the reasons of an abnormal operation in the catalyst cooler and the catalyst riser belonged to the RFCC unit respectively and to estimate the amount of seriousness using sealed gamma-ray source( 60 Co). The catalyst cooler functions cooling for the regeneration of a catalyst, which will be used to a new media in the RFCC unit. The catalyst riser, while, plays an important part in transporting to next cyclotron steps by mixing of an oil, steam and a catalyst mechanically. The purposes of this study is what was the condition of catalyst flow pattern and whether the coke was produced in an inside process or not. Gamma radiation counts were measured by the detector(NaI) positioned outside the pipe-wall diametrically opposite to the gamma source with a regular space. From the results, the section different from the distribution pattern of nearby catalyst in a facility was found. And this became the definitive information to a process operator. Diagnosis technique using gamma radiation source is proved to be the effective and reliable method in providing information on the media distribution in a facility

Applicability of a desiccant dew-point cooling system independent of external water sources

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin Ryhl

2015-01-01

The applicability of a technical solution for making desiccant cooling systems independent of external water sources is investigated. Water is produced by condensing the desorbed water vapour in a closed regeneration circuit. Desorbed water recovery is applied to a desiccant dew-point cooling...... system, which includes a desiccant wheel and a dew point cooler. The system is simulated during the summer period in the Mediterranean climate of Rome and it results completely independent of external water sources. The seasonal thermal COP drops 8% in comparison to the open regeneration circuit solution...

GOTHIC-IST 6.1b code validation exercises relating to heat removal by dousing and air coolers in CANDU containment

International Nuclear Information System (INIS)

Ramachandran, S.; Krause, M.; Nguyen, T.

2003-01-01

This paper presents validation results relating to the use of the GOTHIC containment analysis code for CANDU safety analysis. The validation results indicate that GOTHIC predicts heat removal by dousing and air cooler heat transfer with reasonable accuracy. (author)

Insulated Containers For Bottled Water (ICB)- Performance Evaluation

Science.gov (United States)

2017-04-21

WATER STOWAGE PROTOTYPES BOTTLED WATER HIGH TEMPERATURE WEIGHT EJECTION CONTAINERS ...Soldiers are ineffectively mounting commercially  available  coolers and they,  as well as the bottles they  contain , are becoming projectile hazards... container  (shown in Figure 15). The tie‐down procedures were determined by a professional  rigger; a video of the procedures is  available  from NSRDEC

Water supply method to the fuel cell cooling water system; Nenryo denchi reikyakusuikei eno kyusui hoho

Energy Technology Data Exchange (ETDEWEB)

Urata, T. [Tokyo (Japan); Nishida, S. [Tokyo (Japan)

1996-12-17

The conventional fuel cell has long cooling water piping ranging from the fuel cell exit to the steam separator; in addition, the supply water is cooler than the cooling water. When the amount of supply water increases, the temperature of the cooling water is lowered, and the pressure fluctuation in the steam separator becomes larger. This invention relates to the water supply method of opening the supply water valve and supplying water from the supply water system to the cooling water system in accordance with the signal of the level sensor of the steam separator, wherein opening and closing of the supply valve are repeated during water supply. According to the method the pressure drop in every water supply becomes negligibly small; therefore, the pressure fluctuation of the cooling water system can be made small. The interval of the supply water valve from opening to closing is preferably from 3 seconds to 2 minutes. The method is effective when equipment for recovering heat from the cooling water is installed in the downstream pipeline of the fuel cell. 2 figs.

Design aspects of an electrostatic electron cooler for low-energy RHIC operation

International Nuclear Information System (INIS)

Fedotov, A.; Ben-Zvi, I.; Brodowski, J.; Chang, X.Y.; Gassner, D.; Hoff, L.; Kayran, D.; Kewisch, J.; Oerter, B.; Pendzick, A.; Tepikian, S.; Thieberger, P.; Prost, L.; Shemyakin, A.

2011-01-01

Electron cooling was proposed to increase the luminosity of the Relativistic Heavy Ion Collider (RHIC) operation for heavy ion beam energies below 10 GeV/nucleon. The electron cooling system needed should be able to deliver an electron beam of adequate quality in a wide range of electron beam energies (0.9-5 MeV). An option of using an electrostatic accelerator to produce electrons for cooling heavy ions in RHIC was evaluated in detail. In this paper, we describe the requirements and options which were considered in the design of such a cooler for RHIC, as well as the associated challenges. The expected luminosity improvement and limitations with such an electron cooling system are also discussed.

Experimental study on the thermal management of high-power LED headlight cooling device integrated with thermoelectric cooler package

International Nuclear Information System (INIS)

Wang, Jing; Zhao, Xin-Jie; Cai, Yi-Xi; Zhang, Chun; Bao, Wei-Wei

2015-01-01

Highlights: • A novel TEC cooling system for multi-chip LED module was successfully developed. • Influences of liquid velocity on the system thermal performance were investigated. • TEC system is more sensitive to the input current than that of the mere air cooling. • The junction temperature can be maintained below 61.8 °C (liquid cooling & TEC). - Abstract: In view of the characteristics of high power light-emitting diodes (LEDs), such as strict junction temperature (T j ) control, the enhanced cooling models based on the thermoelectric cooler (TEC) were presented to meet the thermal demand of high-power LED headlight. The cooling performance of different devices (air cooling & TEC, liquid cooling & TEC) was evaluated and compared by measuring the LED case temperature. Details of the heat transfer performance, particularly, the start-up performances of the TEC cooler, as well as the influence of the fan rotate speed or liquid velocity on the system thermal performance were obtained. It was found that the thermal performance had been elevated dramatically due to the reduction of the hot side temperature, and the thermoelectric cooler was more sensitive to the external fan speed or liquid velocity than purely air cooling or liquid cooling. In addition, the optimal current for air cooling & TEC was 3A, and 5A for liquid cooling + TEC. Investigations of the simulated ambient temperature on junction temperature, forward voltage, and output light were conducted. Results indicated that the case temperature changed linear basically with the increase in heating power or the simulated ambient temperature. When the ambient temperature was within its severe level (60–65 °C), the junction temperature could be calculated to 59.5 °C, and the corresponding output light was 1607.3 lm

An analysis of system pressure and temperature distribution in self-pressurizer of SMART and calculation of sizing of wet thermal insulator and pressurizer cooler

Energy Technology Data Exchange (ETDEWEB)

Kang, Yeon Moon; Lee, Doo Jeong; Yoon, Ju Hyun; Kim, Hwan Yeol [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-03-01

To evaluate the amount of heat transfer from coolant to gas in reactor vessel heat transfer through the structure of pressurizer and evaporation/condensation on surface of liquid pool should be considered. And, also the heat exchange by pressurizer cooler and heat transfer to upper plate of reactor vessel should be considered. Thus, overall examinations on design variables which affect the heat transfer from coolant to gas are needed to maintain the pressurizer conditions at designed value for normal operation through heatup process. The major design variables, which affect system pressure and gas temperature during heatup, and the sizes of wet thermal insulator and pressurizer cooler, and volume of gas cylinder connected to pressurizer. A computer program is developed for the prediction of system pressure and temperature of pressurizer gas region with considering volume expansion of coolant and heat transfer from coolant to gas during heatup. Using the program, this report suggests the optimized design values of wet thermal insulator, pressurizer cooler, and volume of gas cylinder to meet the target conditions for normal operation of SMART. (author). 6 refs., 17 figs., 5 tabs.

Efficient on-chip hotspot removal combined solution of thermoelectric cooler and mini-channel heat sink

International Nuclear Information System (INIS)

Hao, Xiaohong; Peng, Bei; Xie, Gongnan; Chen, Yi

2016-01-01

Highlights: • A combined solution of thermoelectric cooler (TEC) and mini-channel heat sink to remove the hotspot of the chip has been proposed. • The TEC's mathematical model is established to assess its work performance. • A comparative study on the proposed efficient On-Chip Hotspot Removal Combined Solution. - Abstract: Hotspot will significantly degrade the reliability and performance of the electronic equipment. The efficient removal of hotspot can make the temperature distribution uniform, and ensure the reliable operation of the electronic equipment. This study proposes a combined solution of thermoelectric cooler (TEC) and mini-channel heat sink to remove the hotspot of the chip in the electronic equipment. Firstly, The TEC's mathematical model is established to assess its work performance under different boundary conditions. Then, the hotspot removal capability of the TEC is discussed for different cooling conditions, which has shown that the combined equipment has better hotspot removal capability compared with others. Finally, A TEC is employed to investigate the hotspot removal capacity of the combined solution, and the results have indicated that it can effectively remove hotspot in the diameter of 0.5 mm, the power density of 600W/cm 2 when its working current is 3A and heat transfer thermal resistance is 0 K/W.

Numerical study on the performance of vacuum cooler and evaporation-boiling phenomena during vacuum cooling of cooked meat

International Nuclear Information System (INIS)

Jin, T.X.; Xu, L.

2006-01-01

The vacuum cooling of cooked meats is described in this paper. Based on the energy and mass balance, a modified mathematical model based on a previous model is developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of cooked meat. Validation experimentation is performed in the designed vacuum cooler. Boiling occurs inside the cooked meat. There is a boiling front, and the boiling front moves toward the center of the cooked meat as the vacuum cooling proceeds. The experimental data are compared with the simulation results. It is found that the differences of the temperature between the simulation and the experimentation are within 5 deg. C, and the deviation of weight loss between the simulation and the experimentation is within 4%. The simulation results agree with the experimental data well. The modified model can be used to predict the variation of the vacuum pressure in the chamber, the temperature and pressure distributions and the weight loss profiles of cylindrical cooked meats

Three-ring stable oxygen isotope ratios indicating cooler and wetter climate conditions and high flood frequency periods in the Red River Basin, Manitoba, Canada

International Nuclear Information System (INIS)

Buhay, W.M.; Harms, P.; Marcino, D.; Mayer, B.; St. George, S.; Nielsen, E.

2002-01-01

In the Red River region of southern Manitoba, Canada, the frequency of flood events tends to increase during cooler and wetter climate conditions. Predictably, recorded Red River flood stages are primarily a result of meteorological conditions which produce an increase runoff due to excess snowmelt and heavy spring precipitation. Winter skewed precipitation periods corresponding to cooler and wetter conditions in the Red River Basin may provide traceable oxygen isotope signals in hydrologically sensitive trees occupying the basin. To test this hypothesis, three overlapping oak tree-ring chronologies (KPO1: 1990 to 1795; STVO1: 1985 to 1797; STVO2: 1990 to 1845) were annually sampled and processed for their cellulose

Can restoration convert a degraded bog in southern Bavaria to a carbon sink and climate cooler?

Science.gov (United States)

Förster, Christoph; Drösler, Matthias

2014-05-01

The peatland area of Germany is about 14.000 km² (Succow & Joosten 2001) with 8% natural like bogs and 4% natural like fens (Höper 2006). All other peatland areas are more or less intensively used and thus, lost their sink function for carbon. If, theoretically, all German peatlands would be rewetted, this restoration would lead to a carbon mitigation of 9.5 Mio. t CO2-C equivalents (Freibauer et al. 2009). In test areas like the studied bog, the viability and potential of peatland restoration for climate mitigation can be proofed. The investigated bog is situated close to the Bavarian Alps; one part of this bog is extensively used and had been rewetted in 1993 except of a small stripe; management was stopped totally at another stripe. The second part of this bog had been drained without any further use. Here a Calluna heath established, accompanied by Pine trees. The restoration of this bog heath was done in two time steps; here a chronosequence of succession after restoration at different water table levels was investigated. To get to the greenhouse gas (GHG) balances of CO2 CH4 and N2O, gas flux measurements were done for two years using the chamber technique of Drösler (2005). At both areas, the degraded sites were sources for GHG (+203 to +736 g CO2-C-equiv m-2 a-1). Restoration reduced these emissions depending on water table and succession of bog species (-51 to +557 g CO2-C-equiv m-2 a-1). Depending on the vegetation's vitality GHG balances of already established natural like sites varied in between the years (-189 to +264 g CO2-C-equiv m-2 a-1) mainly driven by the oscillation of their water table. Stop of management and development of Sphagnum communities turned most of the sites into sinks for GHG (-216 to +7 g CO2-C-equiv m-2 a-1). Thus restoration turned degraded bogs efficiently to carbon sinks and climate coolers in dependence of a proper water table management, withdrawal of land use and vegetation succession. Key words: bog, greenhouse gases

Hybrid coolers under part-load conditions - Optimisation of operating costs and energy consumption; Simulation und Berechnung von hybriden Trockenkuehlern imTeillastbereich - Optimierung von Betriebskosten und Energieverbrauch

Energy Technology Data Exchange (ETDEWEB)

Koenig, H.

2007-07-01

This comprehensive article takes a look at new European guidelines on the energy performance of buildings in which the total efficiency of the buildings or heat-transportation systems under partial loading is considered. On the basis of a real-life example, the author examines the influence of various components such as compressors, pumps and ventilators on energy consumption. Hybrid coolers are looked at and the characteristics of refrigeration machines with respect to varying outside temperature are discussed. Combined cooling for computer centres is examined and switchable, redundant combined systems are looked at. Optimisation of cooling systems for falling outside temperatures and the operation of cold-water systems are looked at. Simulation topics are discussed and optimisation with respect to costs and energy consumption are examined.

General Approach for Composite Thermoelectric Systems with Thermal Coupling: The Case of a Dual Thermoelectric Cooler

Directory of Open Access Journals (Sweden)

Cuautli Yanehowi Flores-Niño

2015-06-01

Full Text Available In this work, we show a general approach for inhomogeneous composite thermoelectric systems, and as an illustrative case, we consider a dual thermoelectric cooler. This composite cooler consists of two thermoelectric modules (TEMs connected thermally in parallel and electrically in series. Each TEM has different thermoelectric (TE properties, namely thermal conductance, electrical resistance and the Seebeck coefficient. The system is coupled by thermal conductances to heat reservoirs. The proposed approach consists of derivation of the dimensionless thermoelectric properties for the whole system. Thus, we obtain an equivalent figure of merit whose impact and meaning is discussed. We make use of dimensionless equations to study the impact of the thermal conductance matching on the cooling capacity and the coefficient of the performance of the system. The equivalent thermoelectric properties derived with our formalism include the external conductances and all intrinsic thermoelectric properties of each component of the system. Our proposed approach permits us changing the thermoelectric parameters of the TEMs and the working conditions of the composite system. Furthermore, our analysis shows the effect of the number of thermocouples on the system. These considerations are very useful for the design of thermoelectric composite systems. We reproduce the qualitative behavior of a commercial composite TEM connected electrically in series.

Supply of clean water to the bearings and mechanical seals of the backup pumps

International Nuclear Information System (INIS)

Jolas, C.

1997-01-01

The purpose of the backup pumps is to cool the primary circuit and pressurised water reactor containment in the case of a primary cooler loss accident. The water taken in by these pumps in the case of accident is loaded with solid particles. In order to ensure correct operation of the bearings and mechanical seals of these machines, they must be supplied with clean water. In other words, the solid particles must be removed from the water intake. Manufacturers generally use cyclonic separators to achieve this. (author)

Multi-objective optimization of cooling air distributions of grate cooler with different clinker particles diameters and air chambers by genetic algorithm

International Nuclear Information System (INIS)

Shao, Wei; Cui, Zheng; Cheng, Lin

2017-01-01

Highlights: • A multi-objective optimization model of air distributions of grate cooler by genetic algorithm is proposed. • Optimal air distributions of different conditions are obtained and validated by measurements. • The most economic average diameters of clinker particles is 0.02 m. • The most economic amount of air chambers is 9. - Abstract: The paper proposes a multi-objective optimization model of cooling air distributions of grate cooler in cement plant based on convective heat transfer principle and entropy generation minimization analysis. The heat transfer and flow models of clinker cooling process are brought out at first. Then the modified entropy generation numbers caused by heat transfer and viscous dissipation are considered as objective functions respectively which are optimized by genetic algorithm simultaneously. The design variables are superficial velocities of air chambers and thicknesses of clinker layer on different grate plates. The model is verified by a set of Pareto optimal solutions and scattered distributions of design variables. Sensitive analysis of average diameters of clinker particles and amount of air chambers are carried out based on the optimization model. The optimal cooling air distributions are compared by heat recovered, energy consumption of cooling fans and heat efficiency of grate cooler. And all of them are selected from the Pareto optimal solutions based on energy consumption of cooling fans minimization. The results show that the most effective and economic average diameter of clinker particles is 0.02 m and the amount of air chambers is 9.

Do cold, low salinity waters pass through the Indo-Sri Lanka Channel during winter?

Digital Repository Service at National Institute of Oceanography (India)

Rao, R.R.; Girishkumar, M.S.; Ravichandran, M.; Gopalakrishna, V.V.; Pankajakshan, T.

cooler, low-salinity waters from the head Bay of Bengal (BoB) into the south-eastern AS. But due to a lack of any direct in situ measurements, it is not clear whether any part of this current that flows through the Indo-Sri Lanka Channel (ISLC...

Assessment on the Reactor Containment Cooling Capability of Kori Unit 1 Under LOCA Conditions with Loss of Offsite Power

International Nuclear Information System (INIS)

Lee, Jin Yong; Park, Jong Woon; Kim, Hyeong Taek

2006-01-01

The fan cooler system is designed to remove heat from containment under postulated accident conditions. During a postulated LOCA concurrent with a Loss of Offsite Power (LOOP), the Component Cooling Water (CCW) pumps that supply cooling water to the fan cooler and the fan that supplies containment air to the fan cooler will temporarily lose power. Then, the high temperature steam in the containment atmosphere will pass over the fan cooler tubing without forced cooling water flow. In that case, boiling may occur in the fan cooler tubes causing steam bubbles to form and pass into the attached CCW piping creating steam voids. Prior to the CCW pumps restart, the presence of steam and subcooled water can induce the potential for water hammer. As the CCW pumps restart, the accumulated steam condenses and the pumped water can produce a water hammer when the void closes. The hydrodynamic loads caused by such a water hammer event could challenge the integrity and the function of the fan cooler and associated CCW system. With respect to this phenomena, the United States Nuclear Regulatory Commission (USNRC) issued the Generic Letter (GL) 96-06, which requests an assessment of the possibility of boiling and water hammer in the cooling water system. The objectives of this study are to develop a analysis method for predicting the thermal hydraulic status of containment fan cooler and then to assess the containment fan cooler of Kori Unit 1 using the developed model under a LOCA with LOOP

Robust Temperature Control of a Thermoelectric Cooler via μ -Synthesis

Science.gov (United States)

Kürkçü, Burak; Kasnakoğlu, Coşku

2018-02-01

In this work robust temperature control of a thermoelectric cooler (TEC) via μ -synthesis is studied. An uncertain dynamical model for the TEC that is suitable for robust control methods is derived. The model captures variations in operating point due to current, load and temperature changes. A temperature controller is designed utilizing μ -synthesis, a powerful method guaranteeing robust stability and performance. For comparison two well-known control methods, namely proportional-integral-derivative (PID) and internal model control (IMC), are also realized to benchmark the proposed approach. It is observed that the stability and performance on the nominal model are satisfactory for all cases. On the other hand, under perturbations the responses of PID and IMC deteriorate and even become unstable. In contrast, the μ -synthesis controller succeeds in keeping system stability and achieving good performance under all perturbations within the operating range, while at the same time providing good disturbance rejection.

Novel concept for driving the linear compressor of a micro-miniature split Stirling cryogenic cooler

Science.gov (United States)

Maron, V.; Veprik, A.; Finkelstein, L.; Vilenchik, H.; Ziv, I.; Pundak, N.

2009-05-01

New methods of carrying out homeland security and antiterrorist operations call for the development of a new generation of mechanically cooled, portable, battery powered infrared imagers, relying on micro-miniature Stirling cryogenic coolers of rotary or linear types. Since split Stirling linearly driven micro-miniature cryogenic coolers have inherently longer life spans, low vibration export and better aural stealth as compared to their rotary driven rivals, they are more suitable for the above applications. The performance of such cryogenic coolers depends strongly on the efficacy of their electronic drivers. In a traditional approach, the PWM power electronics produce the fixed frequency tonal driving voltage/current, the magnitude of which is modulated via a PID control law so as to maintain the desired focal plane array temperature. The disadvantage of such drivers is that they draw high ripple current from the system's power bus. This results in the need for an oversized DC power supply (battery packs) and power electronic components, low efficiency due to excessive conductive losses and high residual electromagnetic interference which in turn degrades the performance of other systems connected to the same power bus. Without either an active line filter or large and heavy passive filtering, other electronics can not be powered from the same power bus, unless they incorporate heavy filtering at their inputs. The authors present the results of a feasibility study towards developing a novel "pumping" driver consuming essentially constant instant battery power/current without making use of an active or passive filter. In the tested setup, the driver relies on a bidirectional controllable bridge, invertible with the driving frequency, and a fast regulated DC/DC converter which maintains a constant level of current consumed from the DC power supply and thus operates in input current control mode. From the experimental results, the steady-state power consumed by the

A Harmonic Kicker Scheme for the Circulator Cooler Ring in the Proposed Medium Energy Electron-Ion Collider

Energy Technology Data Exchange (ETDEWEB)

Nissen, Edward W.; Hutton, Andrew M.; Kimber, Andrew J.

2013-06-01

The current electron cooler design for the proposed Medium Energy Electron-Ion collider (MEIC) at Jefferson Lab utilizes a circulator ring for reuse of the cooling electron bunch up to 100 times to cool the ion beams. This cooler requires a fast kicker system for injecting and extracting individual bunches in the circulator ring. Such a kicker must work at a high repetition rate, up to 7.5 to 75 MHz depending on the number of turns in the recirculator ring. It also must have a very short rise and fall time (of order of 1 ns) such that it will kick an individual bunch without disturbing the others in the ring. Both requirements are orders of magnitude beyond the present state-of-the-art as well as the goals of other on-going kicker R&D programs such as that for the ILC damping rings. In this paper we report a scheme of creating this fast, high repetition rate kicker by combining RF waveforms at multiple frequencies to create a kicker waveform that will, for example, kick every eleventh bunch while leaving the other ten unperturbed. We also present a possible implementation of this scheme as well as discuss its limitations.

10 CFR 431.304 - Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in...

Science.gov (United States)

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in freezers. 431.304 Section 431.304 Energy DEPARTMENT OF ENERGY... measuring, pursuant to EPCA, the energy consumption of refrigerated bottled or canned beverage vending...

Considerations on the application in supermarkets. The high performance air cooler in the course of time; Ueberlegungen fuer die Anwendung im Supermarkt. Der Hochleistungsluftkuehler im Wandel der Zeit

Energy Technology Data Exchange (ETDEWEB)

Lich, Mathias [GEA Kueba GmbH, Baierbrunn (Germany)

2011-08-15

In the last twenty years, the high performant air cooler has undergone a rapid development. Power, energy efficiency and compact size an important role in the selection for the application in the supermarket. The development of the technology of EC fans shows that there always are potentials for an optimal development of products. While an air cooler needed a current consumption of 180 W for the fan twenty years ago, now significantly less than 100 W are necessary. Fan diameter, pipe diameter, shell size and all incorporated components have become more powerful and more efficient.

Cooler Storage Ring at China Institute of Modern Physics

CERN Document Server

Wen-Xia, Jia; Zhan, W

2005-01-01

CSR, a new ion cooler-storage-ring project in China IMP, is a double ring system, and consists of a main ring (CSRm) and an experimental ring (CSRe). The two existing cyclotrons SFC (K=69) and SSC (K=450) of the Heavy Ion Research Facility in Lanzhou (HIRFL) will be used as its injector system. The heavy ion beams with the energy range of 7-30 MeV/nucleus from the HIRFL will be accumulated, cooled and accelerated to the higher energy range of 100-500 MeV/ nucleus in CSRm, and then extracted fast to produce radioactive ion beams or highly charged heavy ions. Those secondary beams will be accepted and stored or decelerated by CSRe for many internal-target experiments or high precision spectroscopy with beam cooling. On the other hand, the beams with the energy range of 100-1000MeV/ nucleus will also be extracted from CSRm by using slow extraction or fast extraction for many external-target experiments. CSR project was started in the end of 1999 and will be finished in 2006. In this paper the outline and the act...

Larval fish assemblages in coastal waters of central Greece: reflections of topographic and oceanographic heterogeneity

Directory of Open Access Journals (Sweden)

Stylianos Somarakis

2011-04-01

Full Text Available Patterns in the mesoscale distribution of larval fish in the coastal waters of central Greece, an area of high topographic and bathymetric complexity, were analysed using samples collected during two ichthyoplankton surveys in July 1998 and June 1999. Salinities were lower in the eastern (Aegean part of the study area due to the influence of waters originating from the Black Sea. In this region, larvae of many epipelagic and benthopelagic (typically summer spawning species were less abundant in June 1999, when waters were significantly cooler, compared to July 1998. Multivariate analyses identified ‘neritic’ and ‘pelagic’ groups of stations dominated by larvae of epipelagic/bethopelagic (typically shelf dwelling and mesopelagic species. In the west (Ionian Sea, a prominent third group of stations located in the deep and highly enclosed Korinthiakos Gulf was also defined with very high abundances of mesopelagic fish larvae. However, the genera Cyclothone and Vinciguerria that dominated the neighbouring offshore assemblage of the Ionian Sea were absent from this gulf. In the study area, Korinthiakós Gulf ( > 900 m and North Evoikos ( > 400 m Gulf comprise unique ‘fjord-like’ ecosystems in the Mediterranean with increased productivity and significantly cooler deep waters compared to adjacent open sea basins.

Dwarfs Cooler Than M: The Definition of Spectral Type L Using Discoveries form the 2-Micron All-Sky Survey (2MASS)

Science.gov (United States)

Kirkpatrick, J.; Reid, I.; Liebert, J.; Cutri, R.; Nelson, B.; Beichan, C.; Dahn, C.; Monet, D.; Gizis, J.; Skrutskie, M.

2000-01-01

Because the TiO and VO bands, which dominate the far-optical portions of late-M spectra, disappear in these cooler dwarfs, we define a new spectral class L in wich metallic oxides are replaced by metallic hydrides and neutral alkali metals as the major spectroscopic signatures.

Development of a Bunched Beam Electron Cooler based on ERL and Circulator Ring Technology for the Jefferson Lab Electron-Ion Collider

Energy Technology Data Exchange (ETDEWEB)

Benson, Stephen V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hannon, Fay E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hutton, Andrew M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Rimmer, Robert A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Roblin, Yves R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, Haipeng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, He [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2018-01-01

Jefferson Lab is in the process of designing an electron ion collider with unprecedented luminosity at a 45 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires novel use of bunched-beam cooling. There are two designs for such a cooler. The first uses a conventional Energy Recovery Linac (ERL) with a magnetized beam while the second uses a circulating ring to enhance both peak and average currents experienced by the ion beam. This presentation will describe the design of both the Circulator Cooling Ring (CCR) design and that of the backup option using the stand-alone ERL operated at lower charge but higher repetition rate than the ERL injector required by the CCR-based design.

Simultaneous high-speed gas property measurements at the exhaust gas recirculation cooler exit and at the turbocharger inlet of a multicylinder diesel engine using diode-laser-absorption spectroscopy.

Science.gov (United States)

Jatana, Gurneesh S; Magee, Mark; Fain, David; Naik, Sameer V; Shaver, Gregory M; Lucht, Robert P

2015-02-10

A diode-laser-absorption-spectroscopy-based sensor system was used to perform high-speed (100 Hz to 5 kHz) measurements of gas properties (temperature, pressure, and H(2)O vapor concentration) at the turbocharger inlet and at the exhaust gas recirculation (EGR) cooler exit of a diesel engine. An earlier version of this system was previously used for high-speed measurements of gas temperature and H(2)O vapor concentration in the intake manifold of the diesel engine. A 1387.2 N m tunable distributed feedback diode laser was used to scan across multiple H(2)O absorption transitions, and the direct absorption signal was recorded using a high-speed data acquisition system. Compact optical connectors were designed to conduct simultaneous measurements in the intake manifold, the EGR cooler exit, and the turbocharger inlet of the engine. For measurements at the turbocharger inlet, these custom optical connectors survived gas temperatures as high as 800 K using a simple and passive arrangement in which the temperature-sensitive components were protected from high temperatures using ceramic insulators. This arrangement reduced system cost and complexity by eliminating the need for any active water or oil cooling. Diode-laser measurements performed during steady-state engine operation were within 5% of the thermocouple and pressure sensor measurements, and within 10% of the H(2)O concentration values derived from the CO(2) gas analyzer measurements. Measurements were also performed in the engine during transient events. In one such transient event, where a step change in fueling was introduced, the diode-laser sensor was able to capture the 30 ms change in the gas properties; the thermocouple, on the other hand, required 7.4 s to accurately reflect the change in gas conditions, while the gas analyzer required nearly 600 ms. To the best of our knowledge, this is the first implementation of such a simple and passive arrangement of high-temperature optical connectors as well

Simulations of injection optics for an RFQ cooler and buncher

CERN Document Server

Eronen, Tommi

2002-01-01

This report is about injection of ions to a new RFQ (which stands for a Radio Frequency Quadrupole) cooler & trap which will be built at ISOLDE, CERN. This device brings very good advantages to existing beamline - for instance, lower emittance in transversal plane and lower energy spread in longitudinal direction. It will be possible to bunch the beam. Lower emittance means that ions can be focused to smaller spot thus improving precision of measurements. For laser experiments bunched beam is much more useful compared to continuous beam. Bunch can be adjusted such that lasers are synchronized with the ion bunch thus increasing signal-to-background ratio. Using buffer gas cooling is also very cost effective and easy to operate - there is only a few tunable parameters in the RFQ. Buffer gas cooling is effective only if ions are much heavier than the buffer gas. Usually this is the case at ISOLDE. One of the most crucial part in the whole RFQ project is the injection. Because of the presence of buffer gas, R...

COSY, proposal for a cooler synchrotron at the KFA Julich

International Nuclear Information System (INIS)

Berg, G.P.A.; Gaul, G.; Hacker, H.

1986-01-01

The Cooler Synchrotron COSY is being planned in cooperation between scientists of the Kernforschungsanlage Julich, nuclear physicists of the neighbouring universities and other interested scientists. COSY is designed to provide beams of very light ions with energies ranging from 40 MeV to a maximum of 2.5 GeV for protons. This energy range allows a variety of studies in the so called energy window between 150 and 500 MeV, and it permits different kinds of investigations in the medium-energy region including the KΛ-threshold. Both electron cooling and stochastic cooling are foreseen in order to obtain very high phase-space density. The existing isochronous cyclotron JULIC will serve as injector. COSY will contain two bending sections, each consisting of three unit cells, and two long straight sections between the bends. Large flexibility is guaranteed by the ion-optical design. Experiments are being planned that make use either of the high quality external beam prepared by slow extraction or of the very high luminosity that is effective in the recirculator mode of operation

Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant; Kombineret brugsvands- og rumvarmepumpe med CO{sub 2} som koelemiddel

Energy Technology Data Exchange (ETDEWEB)

Schoen Poulsen, C. [Teknologisk Institut (Denmark)

2006-05-19

This project report describes the implementation of the Danish project called 'Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant'. In the course of the project, a combined heat pump has been developed for heating sanitary hot water and producing domestic space heating. The project shows that CO2 has excellent properties in systems where a high temperature is desired on the gas cooler side and that it is possible to combine the production of sanitary hot water with the production of domestic space heating. During the project, a number of system solutions have been analysed and at the end of the project a prototype was built. It was tested in the laboratory according to a current Dutch standard for heat pumps for sanitary hot water. The prototype was constructed without the space heat part which solely has been analysed according to calculations. The reason is that there currently are no applicable European standards for the testing of combined systems and as the total efficiency of the system mainly depends on the temperature out of the gas cooler it was decided not to spend resources on the construction of the combined system in the prototype version of the unit. Instead, a number of proposals have been submitted to how the system with a space heat section could be constructed. The main components used in the prototype (compressor, exchangers, valve, control and tank) are all partly commercially available and therefore focus has been on the system construction. During the project, a number of CFD calculations have been carried out on the gas cooler in the hot water tank and the results show how important it is that the gas cooler is designed and placed correctly. The laboratory tests carried out on the unit show that the COP of the heat pump plant in connection with sanitary hot water tapping (according to Dutch standard) is 1.4 1.5 which is not immediately satisfactory. But when it is considered that the unit is a

Ice detection in heat pumps and coolers. [By thermal resistance and capacitance detection

Energy Technology Data Exchange (ETDEWEB)

Buick, T R; McMullan, J T; Morgan, R; Murray, R B

1978-01-01

Some methods are discussed for detecting the formation of ice on the evaporators of air-source heat pumps and air coolers by electronic means. The sensing of thermal resistance caused by ice build-up can be done by measuring temperature differences between the evaporator and the air, and analyses are presented of the effect of using both linear and non-linear temperature sensors for this purpose. The direct detection of the presence of ice can be done by measuring the capacitance of a suitably-placed pair of plates, and the performance of such a system is analyzed. Preliminary reports are presented of the use of both of these methods of ice detection in the defrosting of an experimental heat pump.

Experimental Investigation of 2D thermal signature and 3D X-Ray Computed Tomography in contrasting Wettable and Water-Repellent Beads

Science.gov (United States)

Alsih, Abdulkareem; Flavel, Richard; McGrath, Gavan

2017-04-01

This study presents experimental results investigating spatial patterns of infiltration and evaporation in heterogeneous water repellent media. Infrared camera measurements and 3D X-ray computed tomography imaging was performed across wet-dry cycles on glass beads with engineered patches of water repellence. The imaging revealed spatial variability in infiltration and the redistribution of water in the media resulting in differences in relative evaporation rates during drying. It appears that the spatial organization of the heterogeneity play a role in the breakdown of water repellence at the interface of the two media. This suggests a potential mechanism for self-organization of repellency spatial patterns in field soils. At the interface between wettable and water repellent beads a lateral drying front propagates towards the wettable beads from the repellent beads. During this drying the relative surface temperatures change from a relatively cooler repellent media surface to a relatively cooler wettable media surface indicating the changes in evaporative water loss between the beads of varying water repellence. The lateral drying front was confirmed using thermography in a small-scale model of glass beads with chemically induced repellence and then subjected to 3D X-ray imaging. Pore-scale imaging identified the hydrology at the interface of the two media and at the drying front giving insights into the physics of water flow in water repellent soil.

Airborne exposure to trihalomethanes from tap water in homes with refrigeration-type and evaporative cooling systems.

Science.gov (United States)

Kerger, Brent D; Suder, David R; Schmidt, Chuck E; Paustenbach, Dennis J

2005-03-26

This study evaluates airborne concentrations of common trihalomethane compounds (THM) in selected living spaces of homes supplied with chlorinated tap water containing >85 ppb total THM. Three small homes in an arid urban area were selected, each having three bedrooms, a full bath, and approximately 1000 square feet; two homes had standard (refrigeration-type) central air conditioning and the third had a central evaporative cooling system ("swamp cooler"). A high-end water-use pattern was used at each home in this exposure simulation. THM were concurrently measured on 4 separate test days in tap water and air in the bathroom, living room, the bedroom closest to the bathroom, and outside using Summa canisters. Chloroform (trichloromethane, TCM), bromodichloromethane (BDCM), and dibromochloromethane (DBCM) concentrations were quantified using U.S. EPA Method TO-14. The apparent volatilization fraction consistently followed the order: TCM > BDCM > DBCM. Relatively low airborne THM concentrations (similar to outdoors) were found in the living room and bedroom samples for the home with evaporative cooling, while the refrigeration-cooled homes showed significantly higher THM levels (three- to fourfold). This differential remained after normalizing the air concentrations based on estimated THM throughput or water concentrations. These findings indicate that, despite higher throughput of THM-containing water in homes using evaporative coolers, the higher air exchange rates associated with these systems rapidly clears THM to levels similar to ambient outdoor concentrations.

High power vertical stacked and horizontal arrayed diode laser bar development based on insulation micro-channel cooling (IMCC) and hard solder bonding technology

Science.gov (United States)

Wang, Boxue; Jia, Yangtao; Zhang, Haoyu; Jia, Shiyin; Liu, Jindou; Wang, Weifeng; Liu, Xingsheng

2018-02-01

An insulation micro-channel cooling (IMCC) has been developed for packaging high power bar-based vertical stack and horizontal array diode lasers, which eliminates many issues caused in its congener packaged by commercial copper formed micro-channel cooler(MCC), such as coefficient of thermal expansion (CTE) mismatch between cooler and diode laser bar, high coolant quality requirement (DI water) and channel corrosion and electro-corrosion induced by DI water if the DI-water quality is not well maintained The IMCC cooler separates water flow route and electrical route, which allows tap-water as coolant without electro-corrosion and therefore prolongs cooler lifetime dramatically and escalated the reliability of these diode lasers. The thickness of ceramic and copper in an IMCC cooler is well designed to minimize the CTE mismatch between laser bar and cooler, consequently, a very low "SMILE" of the laser bar can be achieved for small fast axis divergence after collimation. In additional, gold-tin hard solder bonding technology was also developed to minimize the risk of solder electromigration at high current density and thermal fatigue under hard-pulse operation mode. Testing results of IMCC packaged diode lasers are presented in this report.

Laser spectroscopy with a cooler ring at the ESR (GSI) and the TSR (MPI Heidelberg)

International Nuclear Information System (INIS)

Kuehl, T.; Borneis, S.; Greten, G.; Marx, D.; Neumann, R.; Schroeder, S.; Grieser, R.; Hoog, I.; Huber, G.; Klaft, I.; Klein, R.; Merz, P.; Balykin, V.; Bock, M.; Ellert, C.; Forck, P.; Grieser, M.; Grimm, R.; Habs, D.; Miesner, H.J.; Petrich, W.; Wanner, B.; Becker, C.; Schwalm, D.; Wolf, A.

1992-01-01

At the TSR cooler ring at Heidelberg, laser studies were carried out using singly charged lithium and beryllium ions. Laser spectroscopy of relativistic lithium ions (υ = 0.04c) yielded signals with a narrow linewidth, suitable for an experimental test of special relativity. A dramatic reduction of the beam temperature, as defined by the longitudinal velocity spread, was achieved via laser cooling in both cases. At the ion energies available at ESR it will become possible to prepare and store bare ions up to U 92+ . Electron cooling was successfully demonstrated for hydrogen-like Bi 82+ ions, where a laser experiment is scheduled to study the ground-state hyperfine splitting. (orig.)

Numerical investigation on various heat exchanger performances to determine an optimum configuration for charge air cooler, oil and water radiators in F1 sidepods

International Nuclear Information System (INIS)

Salmon, Pierre; Könözsy, László; Temple, Clive; Grove, Stuart

2017-01-01

Highlights: • Three-dimensional CFD transitional flow simulations in formula one car sidepods. • Determination of an optimum heat exchanger configuration placed in the sidepods. • Prediction of heat transfer and pressure drop to mass flow rate correlation curves. • Performance of heat exchanger configurations for non-isothermal transitional flows. • Overcome the difficulties of macroscopic heat exchanger and porous media methods. - Abstract: The present work focuses on a three-dimensional CFD approach to predict the performance of various heat exchangers in conjunction with non-isothermal transitional flows for motorsport applications. The objective of this study is to determine the heat transfer, pressure drop and inhomogeneous flow behaviour for distinct heat exchangers to identify an optimum configuration for the charge air cooler, water and oil radiators placed in the sidepods of a formula one (F1) car. Therefore, a comprehensive analysis of various heat exchanger configurations has been carried out in this work. In order to assess the reliability of the obtained results, a mesh sensitivity study along with additional parametric investigations have been performed to provide numerical parameters predicting accurately (a) the heat transfer rate at the fluid-solid interface and (b) the sporadic separation. As a result of the performed validation procedure in this study, the aerodynamic- and thermal boundary layer development along with the convective characteristics of the air flow have been captured accurately near to the heated surface. The characterization of a heat exchanger core and a core configuration in a closed domain is also possible with this procedure. The presented three-dimensional CFD approach could overcome the difficulties of macroscopic heat exchanger and porous media methods for F1 applications, because it can be used to predict the heat transfer and pressure drop related to the mass flow rate correlation curves. The contribution of

Development of a small Stirling-cycle cooler for spaceflight applications

Energy Technology Data Exchange (ETDEWEB)

Werrett, S.T.; Peskett, G.D.; Davey, G.; Bradshaw, T.W.; Delderfield, J.

1985-01-01

The paper describes the development, from a previously proven design approach, of a robust and simple Stirling-cycle cooler with long-life potential. The need for a closed-cycle refrigerator for use in a spacecraft borne infrared radiometer is explained. The refrigerator is to supply 1 watt of cooling at 80 K for less than 80 watts of input power, be able to survive the launch environment and subsequently run for 26000 hours. Clearance seals achieved with a spring suspension developed from earlier space-proven mechanisms have led to the production of a linear split Stirling-cycle machine with no apparent life limiting features. A servo-control system, in conjunction with moving coil motors and LVDT position sensors, permits running of balanced pairs of mechanisms. The working fluid, helium at a pressure of 1.2 MPa, is contained within titanium bodies having gold O-ring seals. A vacuum-bakeout procedure, based upon experience and outgassing trials, reduces residual contaminant release to acceptable levels. A prototype refrigerator was subjected to a vibration test and has subsequently run for 6000 hours with no detectable change in performance.

Development of a small Stirling cycle cooler for spaceflight applications

International Nuclear Information System (INIS)

Werrett, S.T.; Bradshaw, T.W.; Davey, G.; Delderfield, T.W.; Peskett, G.D.

1986-01-01

This paper describes the development, from a previously proven design approach, of a robust and simple Stirling cycle cooler with long life potential. The need for a closed cycle refrigerator for use in a spacecraft borne infra-red radiometer is explained. The refrigerator is to supply 1 watt of cooling at 80 K for less than 80 watts of input power, be able to survive the launch environment and subsequently run for 26000 hours. Clearance seals achieved with a spring suspension developed from earlier space proven mechanisms have led to the production of a linear split Stirling cycle machine with no apparent life limiting features. A servo control system, in conjunction with moving coil motors and LVDT position sensors, permits running of balanced pairs of mechanisms. The working fluid, helium at a pressure of 1.2 MPa, is contained within titanium bodies having gold O-ring seals. A vacuum bakeout procedure, based upon experience and outgassing trials, reduces residual contaminant release to acceptable levels. A prototype refrigerator has been subjected to a vibration test and has subsequently run for 6000 hours with no detectable change in performance

Measurement of RF characteristics of magnetic alloys for an RF cavity of the accumulator cooler ring

International Nuclear Information System (INIS)

Watanabe, M.; Chiba, Y.; Katayama, T.; Koseki, T.; Ohtomo, K.; Tsutsui, H.

2004-01-01

The magnetic alloy (MA)-loaded RF cavity has been studied for an RF stacking system of the accumulator cooler ring (ACR). RF characteristics of several high-permeability MA cores were measured in the frequency range between 1 and 50 MHz. The effects of the cut-core configuration, cutting the core and leaving air gaps between two circular halves, were also investigated. The results show that the shunt impedance remains high and the appropriate inductance and Q-value can be obtained by increasing the gap width of the cut core in the frequency region of the ACR cavity

Residential CO{sub 2} heat pump system for combined space heating and hot water heating

Energy Technology Data Exchange (ETDEWEB)

Stene, Joern

2004-02-01

the inlet water temperature for the Dh preheating gas cooler unit. The lower the inlet temperature, the higher the Cop. The CO{sub 2} system will therefore achieve the highest COP at low city water temperatures, and when there is negligible mixing and minimum conductive heat transfer between the hot and cold water in the DHW tank during the tapping and charging periods. (5) The COP for the integrated CO{sub 2} heat pump is generally more sensitive to variations in the compressor efficiency than that of conventional brine/water-to-water heat pump systems. It is therefore of particular importance to apply a high-efficiency compressor. (6) At each operating mode and temperature programme, there will be an optimum gas cooler (high-side) pressure that leads to a maximum COP for the integrated CO{sub 2} heat pump. However, at moderate DHW temperatures, the heat pump can be operated at constant high-side pressure in all heating modes with only a minor reduction in the COP. This is favourable, since it simplifies the operation of the system and reduces the first cost. (7) During operation in the combined heating mode, the COP for the integrated CO{sub 2} heat pump may be higher than in the DHW heating mode due to similar temperature approaches at the cold outlet of the gas coolers and lower optimum high-side pressure. The higher the DHW temperature, the larger the COP difference for the operating modes. (8) The integrated CO{sub 2} heat pump system will be more complex than the state-of-the art residential heat pump systems due to the requirement for a tripartite gas cooler, extra valves and tubing for by-pass of fluids, an inverter controlled pump in the DHW circuit as well as an especially designed DHW storage tank. The application of optimum high-side pressure control will further increase the technical and operational complexity of the system. (9) Conductive heat transfer between the DHW and the cold city water in the storage tank during the tapping and charging periods

Study about ion exchange for decreasing the conductivity of water in power plant and refineries

International Nuclear Information System (INIS)

Khosravi, M.; Samani; Hajihosseini, N.

2002-01-01

Water has been used directly or indirectly for industries, its use would be in factories: such as steam or as a cooler or the product of the industrial material. water is used more than other material in many industries and what ever is obtained as the effect of industrial activities, it is destabilising like waste. By the control of P H and reducing (total dissolved solid) of water or decreasing conductivity of water, we can protect boiler from corrosion. We want to study this article for different method of decreasing (TDS) in order to produce <1μs/cm conductivity. The suitable method which is ion exchange system will be selected

Concerning modeling of double-stage water evaporation cooling

Science.gov (United States)

Shatskiy, V. P.; Fedulova, L. I.; Gridneva, I. V.

2018-03-01

The matter of need for setting technical norms for production, as well as acceptable microclimate parameters, such as temperature and humidity, at the work place, remains urgent. Use of certain units should be economically sound and that should be taken into account for construction, assembly, operation, technological, and environmental requirements. Water evaporation coolers are simple to maintain, environmentally friendly, and quite cheap, but the development of the most efficient solutions requires mathematical modeling of the heat and mass transfer processes that take place in them.

A versatile local control system for the LEIR/AD electron cooler

CERN Document Server

MacCaferri, R

1999-01-01

With the end of antiproton physics at LEAR in 1996, the electron cooling device was modified in order that it could be used for experiments with lead ions in 1997 in LEIR and then for installation in the AD machine the following year. As a consequence, as well as the mechanical modifications to the cooler, the control system also needed to be upgraded and it was decided to build a system that could run either from a PC or from a Workstation as used in the accelerator control rooms. This turned out to be the most efficient solution as no support was given for the maintenance of the old control system during the experiments with lead ions. The PC system was realised during the shutdown before the machine experiments started, leaving time during the rest of 1997 to build the VME interface for installation in the AD. In this paper the hardware and software implementations of this new control system are described and some ideas for the near future are also presented.

Water use alternatives for Navajo energy production

International Nuclear Information System (INIS)

Abbey, D.

1979-01-01

The Navajo have substantial resources of coal and uranium, and water use is certain to accompany development of these resources. A variety of supplies, however, are available--water in storage in Navajo Reservoir, water in existing uses which may be transferred, and groundwater. Furthermore, the quantity of water use varies over a wide range depending on the use of water conservation technologies such as dry coolers and wastewater treatment units. Joint management of energy and water resources requires a basic understanding of the water supply and demand alternatives available to the energy industry. Thus, the uses of water for key energy activities--coal and uranium mining, coal transportation (slurry pipelines), and coal conversion (electricity and synthetic gas production) are reviewed. For those activities for which water conservation is feasible, the technologies and estimate costs ($/af saved) are described. The range of water requirements are then compared to energy and water resource estimates. Finally, alternative (not necessarily exclusive) criteria for energy and water resource management are discussed: a) promote energy activities with the lowest minimum water requirements; b) require industry to use low-quality water resources and the most effective water conservation technology; and c) maximize the economic return on Navajo water resources

Cooler temperatures destabilize RNA interference and increase susceptibility of disease vector mosquitoes to viral infection.

Directory of Open Access Journals (Sweden)

Zach N Adelman

Full Text Available The impact of global climate change on the transmission dynamics of infectious diseases is the subject of extensive debate. The transmission of mosquito-borne viral diseases is particularly complex, with climatic variables directly affecting many parameters associated with the prevalence of disease vectors. While evidence shows that warmer temperatures often decrease the extrinsic incubation period of an arthropod-borne virus (arbovirus, exposure to cooler temperatures often predisposes disease vector mosquitoes to higher infection rates. RNA interference (RNAi pathways are essential to antiviral immunity in the mosquito; however, few experiments have explored the effects of temperature on the RNAi machinery.We utilized transgenic "sensor" strains of Aedes aegypti to examine the role of temperature on RNA silencing. These "sensor" strains express EGFP only when RNAi is inhibited; for example, after knockdown of the effector proteins Dicer-2 (DCR-2 or Argonaute-2 (AGO-2. We observed an increase in EGFP expression in transgenic sensor mosquitoes reared at 18°C as compared with 28°C. Changes in expression were dependent on the presence of an inverted repeat with homology to a portion of the EGFP sequence, as transgenic strains lacking this sequence, the double stranded RNA (dsRNA trigger for RNAi, showed no change in EGFP expression when reared at 18°C. Sequencing small RNAs in sensor mosquitoes reared at low temperature revealed normal processing of dsRNA substrates, suggesting the observed deficiency in RNAi occurs downstream of DCR-2. Rearing at cooler temperatures also predisposed mosquitoes to higher levels of infection with both chikungunya and yellow fever viruses.This data suggest that microclimates, such as those present in mosquito breeding sites, as well as more general climactic variables may influence the dynamics of mosquito-borne viral diseases by affecting the antiviral immunity of disease vectors.

Using Solar Hot Water to Address Piping Heat Losses in Multifamily Buildings

Energy Technology Data Exchange (ETDEWEB)

Springer, David [Alliance for Residential Building Innovation, Davis, CA (United States); Seitzler, Matt [Alliance for Residential Building Innovation, Davis, CA (United States); Backman, Christine [Alliance for Residential Building Innovation, Davis, CA (United States); Weitzel, Elizabeth [Alliance for Residential Building Innovation, Davis, CA (United States)

2015-10-01

Solar thermal water heating is most cost effective when applied to multifamily buildings and some states offer incentives or other inducements to install them. However, typical solar water heating designs do not allow the solar generated heat to be applied to recirculation losses, only to reduce the amount of gas or electric energy needed for hot water that is delivered to the fixtures. For good reasons, hot water that is recirculated through the building is returned to the water heater, not to the solar storage tank. The project described in this report investigated the effectiveness of using automatic valves to divert water that is normally returned through the recirculation piping to the gas or electric water heater instead to the solar storage tank. The valves can be controlled so that the flow is only diverted when the returning water is cooler than the water in the solar storage tank.

Water cooler towers and other man-made aquatic systems as environmental collection systems for agents of concern

Science.gov (United States)

Brigmon, Robin; Kingsley, Mark T.

2018-04-03

An apparatus and process of using existing process water sources such as cooling towers, fountains, and waterfalls is provided in which the water sources are utilized as monitoring system for the detection of environmental agents which may be present in the environment. The process water is associated with structures and have an inherent filtering or absorbing capability available in the materials and therefore can be used as a rapid screening tool for quality and quantitative assessment of environmental agents.

Estimating survival rates of quagga mussel (Dreissena rostriformis bugensis veliger larvae under summer and autumn temperature regimes in residual water of trailered watercraft at Lake Mead, USA

Directory of Open Access Journals (Sweden)

Wook Jin Choi

2013-01-01

Full Text Available On 6 January 2007, invasive quagga mussels [Dreissena rostriformis bugensis (Andrusov, 1897] were discovered in the Boulder Basin ofLake Mead, Nevada, a popular site for recreational boating in the southwestern United States. Recreational watercraft are considered aprimary vector for overland dispersal of quagga mussel veliger larvae between water bodies. Thus, effective decontamination of veligers inresidual water carried by trailered recreation boats is critical to controlling this species’ spread. The survival rate of quagga mussel veligerswas measured during exposure to environmental temperature conditions mimicking those experienced in the residual water of traileredvessels during warm summer and cooler autumn months in the semi-arid southwestern United States. Under warm summer conditions,quagga mussel veligers survived approximately five days while under cooler autumn conditions they survived 27 days. When tested underautumn temperature conditions veliger survival times increased with increased level of larval development. The results suggested a greaterlikelihood of veliger transport in the residual water of trailered watercraft during autumn months. The results indicated that presentlyrecommended vessel quarantine times to kill all externally attached juvenile and adult dreissenid mussels prior to launching in an uninfested water body should be increased to generate 100% veliger mortality in residual water unable to be fully drained from the internal areas of watercraft.

Thermal performance of a modified ammonia–water power cycle for reclaiming mid/low-grade waste heat

International Nuclear Information System (INIS)

Junye, Hua; Yaping, Chen; Jiafeng, Wu

2014-01-01

Highlights: • A modified Kalina cycle is proposed for power and heat cogeneration from mid/low-grade waste heat. • A water-cooling solution cooler is set for cogeneration of sanitary or heating hot water. • Work concentration is determined for suitable turbine inlet pressure and positive back pressure. • Basic concentration should match work concentration for higher efficiency. • Sanitary water with 50.7 °C and capacity of a quarter of total reclaimed heat load is cogenerated. - Abstract: A modified Kalina cycle was simulated, which is a triple-pressure ammonia–water power cycle adding a preheater and a water-cooling solution cooler to the original loop. The cycle acquires higher power recovery efficiency by realizing proper internal recuperation and suitable temperature-difference in phase change processes to match both heat source and cooling water. The influences of some key parameters on the thermodynamic performance of the cycle were discussed, including the work and basic concentrations of solution, circulation multiple and the turbine inlet temperature. It is shown that the basic concentration should match the work concentration for higher efficiency. Although higher work concentration could be slightly beneficial to cycle efficiency, the work concentration is mainly determined by considering the suitable turbine inlet/back pressure. Besides, this cycle can be used as a cogeneration system of power and sanitary or heating hot water. The calculation example presented finally with the turbine inlet parameters of 300 °C/6 MPa and the cycle lowest temperature of 30 °C shows that the power recovery efficiency reaches 15.87%, which is about 16.6% higher than that of the steam Rankine cycle. And it also provides 50.7 °C sanitary water with about a quarter of the total heating load reclaimed

First use of a laser-driven polarized H/D target at the IUCF cooler

International Nuclear Information System (INIS)

Bailey, K.; Brack, J.; Cadman, R. V.; Cummings, W. J.; Fedchak, J.; Fox, B.; Gao, H.; Grosshauser, C.; Holt, R. J.; Jones, C.; Kinney, E.; Kowalczyk, R.; Lu, Z.-T.; Miller, M. A.; Nagengast, W.; Owen, B.; Rith, K.; Schmidt, F.; Schulte, E.; Sowinski, J.; Sperisen, F.; Stenger, J.; Thorsland, E.; Williamson, S.

1997-01-01

The HERMES Laser-Driven Target Task Force (Argonne, Erlangen and Illinois) is charged with developing a polarized H/D target for use in the HERA ring at DESY. Rapid progress was made in the beginning of 1996, leading us to the decision to test the target in a realistic experimental environment. In particular, polarizations of 0.6 and flows above 10 18 atoms·s -1 have been achieved on the bench. The laser-driven target and a simple detector system are currently installed in Cooler storage ring at the Indiana University Cyclotron Facility in order to test its applicability to nuclear physics experiments. Target polarizations are being measured using the rvec H(p, p) and rvec D(p, p) reactions. Initial tests were reasonably successful and the target is well along toward becoming viable for nuclear physics

Building America Case Study: Addressing Multifamily Piping Losses with Solar Hot Water, Davis, California

Energy Technology Data Exchange (ETDEWEB)

2016-12-01

Solar thermal water heating is most cost effective when applied to multifamily buildings and some states offer incentives or other inducements to install them. However, typical solar water heating designs do not allow the solar generated heat to be applied to recirculation losses, only to reduce the amount of gas or electric energy needed for hot water that is delivered to the fixtures. For good reasons, hot water that is recirculated through the building is returned to the water heater, not to the solar storage tank. The project described in this report investigated the effectiveness of using automatic valves to divert water that is normally returned through the recirculation piping to the gas or electric water heater instead to the solar storage tank. The valves can be controlled so that the flow is only diverted when the returning water is cooler than the water in the solar storage tank.

High Surface Area Nanoporous Ti02 Coating for Effective Water Condensation.

Science.gov (United States)

Kaynar, Mehmet; McGarity, Mark; Yassitepe, Emre; Shah, S.

2013-03-01

A water collection device utilizing nanoparticles has been researched, towards the possible goal of providing water in much needed areas on Earth. Titanium dioxide nanoparticles were spray coated on stainless steel substrates to measure their effect on atmospheric water condensation. A simple thermoelectric cooler, also called a Peltier device, was used to lower the temperature of the coated and uncoated stainless steel substrates to below the dew point temperature of the surrounding air. The thickness of the spray coating was varied to measure its effect on water condensation. This increase in surface area had a direct effect on the amount of water condensed. Compared with bare stainless steel, the TiO2 spray coated stainless steel had a considerably smaller contact angle of H20 droplets. In addition, the super-hydrophilic properties of TiO2 allowed water to flow more easily off the device. Supported by TUBITAK-BIDEB 2214-Abroad Research Scholarship program.

Sorghum Landrace Collections from Cooler Regions of the World Exhibit Magnificent Genetic Differentiation and Early Season Cold Tolerance

Directory of Open Access Journals (Sweden)

Frank Maulana

2017-05-01

Full Text Available Cold temperature is an important abiotic stress affecting sorghum production in temperate regions. It reduces seed germination, seedling emergence and seedling vigor thus limiting the production of the crop both temporally and spatially. The objectives of this study were (1 to assess early season cold temperature stress response of sorghum germplasm from cooler environments and identify sources of tolerance for use in breeding programs, (2 to determine population structure and marker-trait association among these germplasms for eventual development of marker tools for improving cold tolerance. A total of 136 sorghum accessions from cooler regions of the world were phenotyped for seedling growth characteristics under cold temperature imposed through early planting. The accessions were genotyped using 67 simple sequence repeats markers spanning all ten linkage groups of sorghum, of which 50 highly polymorphic markers were used in the analysis. Genetic diversity and population structure analyses sorted the population into four subpopulations. Several accessions distributed in all subpopulations showed either better or comparable level of tolerance to the standard cold tolerance source, Shan qui red. Association analysis between the markers and seedling traits identified markers Xtxp34, Xtxp88, and Xtxp319 as associated with seedling emergence, Xtxp211 and Xtxp304 with seedling dry weight, and Xtxp20 with seedling height. The markers were detected on chromosomes previously found to harbor QTLs associated with cold tolerance in sorghum. Once validated these may serve as genomic tools in marker-assisted breeding or for screening larger pool of genotypes to identify additional sources of cold tolerance.

Changes of reproductive system of pike Esox Lucius L. in lake Drukshiai -the cooler of Ignalina NPP

International Nuclear Information System (INIS)

Lukshiene, D.

1995-01-01

On studying the reproductive system of pike in lake Drukshiai during 1992-1994 the same changes in fish gameto- and gonadogenesis as in other coolers were observed: -intensification of gametogenesis processes - earlier sexual maturity; -changes in gonadogenesis processes - a bias of all stages of sexual cycle as well as a change in duration; -disturbance of gametogenesis processes - total and partial degeneration of oocytes causing the disturbance of reproduction cycle what is reflected in the changes of some biological indices (gonadosomatic index and oocyte diameter). The above mentioned disturbances have a negative effect on normal functioning and reproduction of a pike population. (author). 8 refs., 2 figs

Operational cost minimization in cooling water systems

Directory of Open Access Journals (Sweden)

Castro M.M.

2000-01-01

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

The refrigerant plant engineer. Vol. 2. Application of coldness. 4. new rev. and enl. ed.; Der Kaelteanlagenbauer. Bd. 2. Kaelteanwendungen

Energy Technology Data Exchange (ETDEWEB)

Breidenbach, Karl

2004-07-01

Specialists within the range of the refrigerant plant engineering need comprehensive knowledge in the everyday life of occupation. The standard work under consideration very vividly offers an introduction to the technology of refrigerant plants. The second volume of this standard work contains the following chapters: Evaporator; Air cooler and liquid cooler; Air humidification in the cooled room; Condensor; Evaporation cooler and hybrid cooler, cooling towers; Refrigeration compressor; Coolant filling material; Two-phase coolant (binary ice); Water cooling machine with water as refrigerants; Fluid mechanical fundamentals; Expansion valves; Control and adjustment of refrigerant plants; Dimensioning of components; Planning fundamentals; Dimensioning of refrigerant leading pipes for refrigerants.

Upgrade of the radio frequency quadrupole cooler and buncher for the HIE-ISOLDE project

CERN Document Server

Babcock, Carla

2013-01-01

The upgrade to the ISOLDE facility, HIE-ISOLDE, will include an upgrade to the RFQCB (radio frequency quadrupole cooler and buncher), the focus of which will be fixing the problems of alignment with the current machine, improving the integrity of the vacuum system, stabilizing the internal gas pressure, and the changes associated with a new position. The beam passage inside the RFQCB has been simulated with an independent code to highlight the importance of the internal gas pressure, to motivate design changes in the new RFQCB and to explain ways to improve the performance of the current machine. The suspected misalignment of ISCOOL has been quantified, and, using a simulation of ions passing through the external injection electrodes, the effect of the misalignment on machine acceptance has been detailed. Plans for the future RFQCB test stand and HIE-ISOLDE installation have been outlined. (C) 2013 Elsevier B.V. All rights reserved.

Numerical Analysis and Design of Thermal Management System for Lithium Ion Battery Pack Using Thermoelectric Coolers

Directory of Open Access Journals (Sweden)

Yong Liu

2014-08-01

Full Text Available A new design of thermal management system for lithium ion battery pack using thermoelectric coolers (TECs is proposed. Firstly, the 3D thermal model of a high power lithium ion battery and the TEC is elaborated. Then the model is calibrated with experiment results. Finally, the calibrated model is applied to investigate the performance of a thermal management system for a lithium ion battery pack. The results show that battery thermal management system (BTMS with TEC can cool the battery in very high ambient temperature. It can also keep a more uniform temperature distribution in the battery pack than common BTMS, which will extend the life of the battery pack and may save the expensive battery equalization system.

Supply of clean water to the bearings and mechanical seals of the backup pumps; Alimentation en eau propre des paliers et garnitures mecaniques des pompes de sauvetage

Energy Technology Data Exchange (ETDEWEB)

Jolas, C. [Department Machines, Service Ensembles de Production, Direction des Etudes et Recherches, Electricite de France (EDF), 92 - Clamart (France)

1997-01-01

The purpose of the backup pumps is to cool the primary circuit and pressurised water reactor containment in the case of a primary cooler loss accident. The water taken in by these pumps in the case of accident is loaded with solid particles. In order to ensure correct operation of the bearings and mechanical seals of these machines, they must be supplied with clean water. In other words, the solid particles must be removed from the water intake. Manufacturers generally use cyclonic separators to achieve this. (author) 5 refs., 14 figs.

Geometric optimization of thermoelectric coolers in a confined volume using genetic algorithms

International Nuclear Information System (INIS)

Cheng, Y.-H.; Lin, W.-K.

2005-01-01

The demand for thermoelectric coolers (TEC) has grown significantly because of the need for a steady, low-temperature operating environment for various electronic devices such as laser diodes, semiconductor equipment, infrared detectors and others. The cooling capacity and its coefficient of performance (COP) are both extremely important in considering applications. Optimizing the dimensions of the TEC legs provides the advantage of increasing the cooling capacity, while simultaneously considering its minimum COP. This study proposed a method of optimizing the dimensions of the TEC legs using genetic algorithms (GAs), to maximize the cooling capacity. A confined volume in which the TEC can be placed and the technological limitation in manufacturing a TEC leg were considered, and three parameters - leg length, leg area and the number of legs - were taken as the variables to be optimized. The constraints of minimum COP and maximum cost of the material were set, and a genetic search was performed to determine the optimal dimensions of the TEC legs. This work reveals that optimizing the dimensions of the TEC can increase its cooling capacity. The results also show that GAs can determine the optimal dimensions according to various input currents and various cold-side operating temperatures

A technique to simulate a tube break in a high-pressure gas/cooling water heat exchanger - HTR2008-58161

International Nuclear Information System (INIS)

Antwerpen, H. J. V.; Mulder, E. J.

2008-01-01

The gas cycles of most High Temperature Gas-Cooled Reactors (HTR's) reject heat to water at some stage. In the helium/water heat exchangers of HTR's with direct Brayton cycles, the helium is usually at a much higher pressure than the water. If the pressure boundary between the helium and the water fails inside the heat exchanger. the effect on the rest of the water system has to be established in order to do a proper system design. This can be done most efficiently by using a system simulation code, however, very few system simulation codes has the capability to do gas/liquid interface tracking as required for this problem. This study describes a calculation method with which a gas/liquid heat exchanger tube rupture can be calculated in a simulation code without interface tracking. The course of events after tube rupture is described and appropriate calculation models derived. A mathematical model for a pressure relief valve (PRV) was also created. The calculation models were implemented in the system simulation software Flownex and used to study a tube rupture on a 5000 kPa helium/water heat exchanger. The assembled calculation network solved stable and within reasonable time. The simulation provided insight into the course of events following the tube break. It was shown that the acceleration of water out of the helium cooler, by choked-flow helium, caused the main pressure pulses during the event. The maximum pressure in the water loop occurs on the opposite side of the helium cooler due to constructive interference of the initial pressure wave with itself. It was also shown that by changing only pipe lengths, the system could become prone to severe oscillations after a tube rupture event. (authors)

Optimal operation of thermoelectric cooler driven by solar thermoelectric generator

International Nuclear Information System (INIS)

Khattab, N.M.; El Shenawy, E.T.

2006-01-01

The possibility of using a solar thermoelectric generator (TEG) to drive a small thermoelectric cooler (TEC) is studied in the present work. The study includes the theory of both the TEG and the TEC, giving special consideration to determination of the number of TEG modules required to power the TEC to achieve the best performance of the TEG-TEC system all year round. Commercially available thermoelectric modules (TE) are used in the system. The TEG contains 49 thermocouples and the TEC contains 127 thermocouples. A simple arrangement of plane reflectors that are designed to receive maximum solar energy during noon time is used to heat the TEG. Performance tests are conducted to determine both the physical properties and the performance curves of the available TE modules. Also, empirical relations describing the performance of the TEG and TEC modules have been established. These relations are used to develop a mathematical model simulating the TEG-TEC system to predict its performance all year round under the actual climatic conditions of Cairo, Egypt (30 deg. N latitude). The model results are used to determine the number of TEG modules required to drive a single TEC module at maximum cooling capacity. The results show that five thermocouples of the TEG can drive one thermocouple of the TEC, which coincides with the previous theory of the TEG-TEC. This means that 10 of the used TEG modules are required to power the used TEC at optimum performance most times of the year

Simulating future water temperatures in the North Santiam River, Oregon

Science.gov (United States)

Buccola, Norman; Risley, John C.; Rounds, Stewart A.

2016-01-01

A previously calibrated two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Detroit Lake in western Oregon was used in conjunction with inflows derived from Precipitation-Runoff Modeling System (PRMS) hydrologic models to examine in-lake and downstream water temperature effects under future climate conditions. Current and hypothetical operations and structures at Detroit Dam were imposed on boundary conditions derived from downscaled General Circulation Models in base (1990–1999) and future (2059–2068) periods. Compared with the base period, future air temperatures were about 2 °C warmer year-round. Higher air temperature and lower precipitation under the future period resulted in a 23% reduction in mean annual PRMS-simulated discharge and a 1 °C increase in mean annual estimated stream temperatures flowing into the lake compared to the base period. Simulations incorporating current operational rules and minimum release rates at Detroit Dam to support downstream habitat, irrigation, and water supply during key times of year resulted in lower future lake levels. That scenario results in a lake level that is above the dam’s spillway crest only about half as many days in the future compared to historical frequencies. Managing temperature downstream of Detroit Dam depends on the ability to blend warmer water from the lake’s surface with cooler water from deep in the lake, and the spillway is an important release point near the lake’s surface. Annual average in-lake and release temperatures from Detroit Lake warmed 1.1 °C and 1.5 °C from base to future periods under present-day dam operational rules and fill schedules. Simulated dam operations such as beginning refill of the lake 30 days earlier or reducing minimum release rates (to keep more water in the lake to retain the use of the spillway) mitigated future warming to 0.4 and 0.9 °C below existing operational scenarios during the critical autumn spawning period for endangered

Simulating future water temperatures in the North Santiam River, Oregon

Science.gov (United States)

Buccola, Norman L.; Risley, John C.; Rounds, Stewart A.

2016-04-01

A previously calibrated two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Detroit Lake in western Oregon was used in conjunction with inflows derived from Precipitation-Runoff Modeling System (PRMS) hydrologic models to examine in-lake and downstream water temperature effects under future climate conditions. Current and hypothetical operations and structures at Detroit Dam were imposed on boundary conditions derived from downscaled General Circulation Models in base (1990-1999) and future (2059-2068) periods. Compared with the base period, future air temperatures were about 2 °C warmer year-round. Higher air temperature and lower precipitation under the future period resulted in a 23% reduction in mean annual PRMS-simulated discharge and a 1 °C increase in mean annual estimated stream temperatures flowing into the lake compared to the base period. Simulations incorporating current operational rules and minimum release rates at Detroit Dam to support downstream habitat, irrigation, and water supply during key times of year resulted in lower future lake levels. That scenario results in a lake level that is above the dam's spillway crest only about half as many days in the future compared to historical frequencies. Managing temperature downstream of Detroit Dam depends on the ability to blend warmer water from the lake's surface with cooler water from deep in the lake, and the spillway is an important release point near the lake's surface. Annual average in-lake and release temperatures from Detroit Lake warmed 1.1 °C and 1.5 °C from base to future periods under present-day dam operational rules and fill schedules. Simulated dam operations such as beginning refill of the lake 30 days earlier or reducing minimum release rates (to keep more water in the lake to retain the use of the spillway) mitigated future warming to 0.4 and 0.9 °C below existing operational scenarios during the critical autumn spawning period for endangered salmonids. A

Gateways and Water Mass Mixing in the Late Cretaceous North Atlantic

Science.gov (United States)

Asgharian Rostami, M.; Martin, E. E.; MacLeod, K. G.; Poulsen, C. J.; Vande Guchte, A.; Haynes, S.

2017-12-01

Regions of intermediate/deep water formation and water-mass mixing in the North Atlantic are poorly defined for the Late Cretaceous, a time of gateway evolution and cooler conditions following the Mid Cretaceous greenhouse. Improved proxy data combined with modeling efforts are required to effectively evaluate the relationship between CO2, paleogeography, and circulation during this cooler interval. We analyzed and compiled latest Cretaceous (79 - 66 Ma) ɛNd and δ13C records from seven bathyal (paleodepths 0.2 - 2 km) and eight abyssal (paleodepths > 2 km) sites in the North Atlantic. Data suggest local downwelling of Northern Component Water (NCW; ɛNd -9.5 and δ13C 1.7 ‰) is the primary source of intermediate/deep water masses in the basin. As this water flows southward and ages, δ13C values decrease and ɛNd values increase; however, additional chemical changes at several sites require mixing with contributions from several additional water masses. Lower ɛNd ( -10) and higher δ13C ( 1.9 ‰) values in the deep NW part of the basin indicate proximal contributions from a region draining old continental crust, potentially representing deep convection following opening of the Labrador Sea. In the deep NE Iberian Basin, higher ɛNd ( -7) and lower δ13C ( 0.8 ‰) during the Campanian suggest mixing with a Tethyan source (ɛNd -7 and δ13C 0.1 ‰) whose importance decreased with restriction of that gateway in the Maastrichtian. Data from bathyal sites suggest additional mixing. In the SE Cape Verde region, observed ɛNd variations from -10 in the Campanian to -13 and -12 in the early and late Maastrichtian, respectively, may record variations in output rates of Tethyan and/or NCW sources and Demerara Bottom Water (ɛNd -16), a proposed warm saline intermediate water mass formed in shallow, equatorial seas. Pacific inflow through the Caribbean gateway impacts intermediate sites at Blake Nose (ɛNd values -8), particularly the shallowest site during the late

Natural convection in a water tank with a heated horizontal plate facing downward

International Nuclear Information System (INIS)

Yang, Sun Kyoo; Jung, Moon Kee; Helmut Hoffmann

1995-01-01

Experimental and computational studies were carried out to investigate the natural convection of the single phase flow in a tank with a heated horizontal plate facing downward. This is a simplified model for investigations of the influence of a core melt at the bottom of a reactor vessel on the thermal hydraulic behavior in a water filled cavity surrounding the vessel. In this case the vessel is simulated by a hexahedron insulated box with a heated plate horizontally mounted at the bottom of the box. The box with the heated plate is installed in a water filled hexahedron tank. Coolers are immersed in the U-type water volume between the box and the tank. Although the multicomponent flows exist more probably below the heated plate in reality, present study concentrates on the single phase flow in a first step prior to investigating the complicated multicomponent thermal hydraulic phenomena. In the present study, in order to get a better understanding for the natural convection characteristics below the heated plate, the velocity and temperature are measured by LDA(Laser Doppler Anemometry) and thermocouples, respectively. And flow fields are visualized by taking pictures of the flow region with suspended particles. The results show the occurrence of a very effective circulation of the fluid in the whole flow area as the heater and coolers are put into operation. In the remote region below the heated plate the flow is nearly stagnant, and a remarkable temperature stratification can be observed with very thin thermal boundary. Analytical predictions using the FLUTAN code show a reasonable matching of the measured velocity fields. 18 figs., 2 tabs., 18 refs. (Author)

Optimization Of Thermo-Electric Coolers Using Hybrid Genetic Algorithm And Simulated Annealing

Directory of Open Access Journals (Sweden)

Khanh Doan V.K.

2014-06-01

Full Text Available Thermo-electric Coolers (TECs nowadays are applied in a wide range of thermal energy systems. This is due to their superior features where no refrigerant and dynamic parts are needed. TECs generate no electrical or acoustical noise and are environmentally friendly. Over the past decades, many researches were employed to improve the efficiency of TECs by enhancing the material parameters and design parameters. The material parameters are restricted by currently available materials and module fabricating technologies. Therefore, the main objective of TECs design is to determine a set of design parameters such as leg area, leg length and the number of legs. Two elements that play an important role when considering the suitability of TECs in applications are rated of refrigeration (ROR and coefficient of performance (COP. In this paper, the review of some previous researches will be conducted to see the diversity of optimization in the design of TECs in enhancing the performance and efficiency. After that, single-objective optimization problems (SOP will be tested first by using Genetic Algorithm (GA and Simulated Annealing (SA to optimize geometry properties so that TECs will operate at near optimal conditions. Equality constraint and inequality constraint were taken into consideration.

Water temperature effects from simulated changes to dam operations and structures in the Middle and South Santiam Rivers, Oregon

Science.gov (United States)

Buccola, Norman L.

2017-05-31

Green Peter and Foster Dams on the Middle and South Santiam Rivers, Oregon, have altered the annual downstream water temperature profile (cycle). Operation of the dams has resulted in cooler summer releases and warmer autumn releases relative to pre-dam conditions, and that alteration can hinder recovery of various life stages of threatened spring-run Chinook salmon (Oncorhyncus tshawytscha) and winter steelhead (O. mykiss). Lake level management and the use of multiple outlets from varying depths at the dams can enable the maintenance of a temperature regime more closely resembling that in which the fish evolved by releasing warm surface water during summer and cooler, deeper water in the autumn. At Green Peter and Foster Dams, the outlet configuration is such that temperature control is often limited by hydropower production at the dams. Previously calibrated CE-QUAL-W2 water temperature models of Green Peter and Foster Lakes were used to simulate the downstream thermal effects from hypothetical structures and modified operations at the dams. Scenarios with no minimum power production requirements allowed some releases through shallower and deeper outlets (summer and autumn) to achieve better temperature control throughout the year and less year-to-year variability in autumn release temperatures. Scenarios including a hypothetical outlet floating 1 meter below the lake surface resulted in greater ability to release warm water during summer compared to existing structures. Later in Autumn (October 15–December 31), a limited amount of temperature control was realized downstream from Foster Dam by scenarios limited to operational changes with existing structures, resulting in 15-day averages within 1.0 degree Celsius of current operations.

Drought and Cooler Temperatures Are Associated with Higher Nest Survival in Mountain Plovers

Directory of Open Access Journals (Sweden)

Victoria J. Dreitz

2012-06-01

Full Text Available Native grasslands have been altered to a greater extent than any other biome in North America. The habitats and resources needed to support breeding performance of grassland birds endemic to prairie ecosystems are currently threatened by land management practices and impending climate change. Climate models for the Great Plains prairie region predict a future of hotter and drier summers with strong multiyear droughts and more frequent and severe precipitation events. We examined how fluctuations in weather conditions in eastern Colorado influenced nest survival of an avian species that has experienced recent population declines, the Mountain Plover (Charadrius montanus. Nest survival averaged 27.2% over a 7-yr period (n = 936 nests and declined as the breeding season progressed. Nest survival was favored by dry conditions and cooler temperatures. Projected changes in regional precipitation patterns will likely influence nest survival, with positive influences of predicted declines in summer rainfall yet negative effects of more intense rain events. The interplay of climate change and land use practices within prairie ecosystems may result in Mountain Plovers shifting their distribution, changing local abundance, and adjusting fecundity to adapt to their changing environment.

How to repel hot water from a superhydrophobic surface?

KAUST Repository

Yu, Zhejun

2014-01-01

Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a superhydrophobic surface loses its superhydrophobicity in contact with water hotter than 50 °C. Such a phenomenon was recently demonstrated by Liu et al. [J. Mater. Chem., 2009, 19, 5602], using both natural lotus leaf and artificial leaf-like surfaces. However, our work has shown that superhydrophobic surfaces maintained their superhydrophobicity, even in water at 80 °C, provided that the leaf temperature is greater than that of the water droplet. In this paper, we report on the wettability of water droplets on superhydrophobic thin films, as a function of both their temperatures. The results have shown that both the water contact and slide angles on the surfaces will remain unchanged when the temperature of the water droplet is greater than that of the surface. The water contact angle, or the slide angle, will decrease or increase, however, with droplet temperatures increasingly greater than that of the surfaces. We propose that, in such cases, the loss of superhydrophobicity of the surfaces is caused by evaporation of the hot water molecules and their condensation on the cooler surface. © 2014 the Partner Organisations.

Effect of water side deposits on the energy performance of coal fired thermal power plants

International Nuclear Information System (INIS)

Bhatt, M. Siddhartha

2006-01-01

This paper presents the effects of water side deposits in the 210 MW coal fired thermal power plant components (viz., boiler, turbine, feed water heaters, condensers and lube oil coolers) on the energy efficiency of these components and that of the overall system at 100% maximum continuous rating (MCR). The origin, composition and rate of build up of deposits on the water side are presented. A linear growth rate of deposits is assumed for simplicity. The effects of the reduction in heat transfer, increased pressure drop and increased pumping power/reduced power output in the components are quantified in the form of curve fits as functions of the deposit thickness (μm). The reduction in heat transfer in the boiler components is in the range of 0.2-2.0% under normal scaling. The increased pumping power is of the order of 0.6-7.6% in the boiler components, 29% in the BFP circuit, 26% in the LPH circuit, 21% in the HPH circuit and 18% in the lube oil cooler circuits. The effects on the overall coal fired plant is quantified through functional relations between the efficiencies and the notional deposit thickness. The sensitivity indices to the notional deposit thickness are: boiler efficiency: -0.0021% points/μm, turbine circuit efficiency: -0.0037% points/μm, auxiliary power efficiency: -0.00129% points/μm, gross overall efficiency: -0.0039% points/μm and net overall efficiency: -0.0040% points/μm. The overall effect of scale build up is either increased power input of ∼68 kW/μm (at a constant power output) or decreased power output ∼25 kW/μm (at a constant power input). Successful contaminant control techniques are highlighted. Capacity reduction effects due to water side deposits are negligible

Development of a radio-frequency quadrupole cooler for high beam currents

Science.gov (United States)

Boussaid, Ramzi; Ban, G.; Quéméner, G.; Merrer, Y.; Lorry, J.

2017-12-01

The SHIRaC prototype is a recently developed radio-frequency quadrupole (RFQ) beam cooler with an improved optics design to deliver the required beam quality to a high resolution separator (HRS). For an isobaric separation of isotopes, the HRS demands beams with emittance not exceeding 3 π mm mrad and longitudinal energy spread ˜1 eV . Simulation studies showed a significant contribution of the buffer gas diffusion, space charge effect and mainly the rf fringe field to degrade the achieved beam quality at the RFQ exit. A miniature rf quadrupole (μ RFQ ) has been implemented at that exit to remove the degrading effects and provide beams with 1 eV of energy spread and around 1.75 π mm mrad of emittance for 4 Pa gas pressure. This solution enables also to transmit more than 60% of the incoming ions for currents up to 1 μ A . Detailed studies of this development are presented and discussed in this paper. Transport of beams from SHIRaC towards the HRS has been done with an electrostatic quadrupole triplet. Simulations and first experimental tests showed that more than 95% of ions can reach the HRS. Because SPIRAL-2 beams are of high current and very radioactive, the buffer gas will be highly contaminated. Safe maintenance of the SHIRaC beam line needs exceptional treatment of radioactive contaminants. For that, special vinyl sleep should be mounted on elements to be maintained. A detailed maintenance process will be presented.

Multi-stage circulating fluidized bed syngas cooling

Science.gov (United States)

Liu, Guohai; Vimalchand, Pannalal; Guan, Xiaofeng; Peng, WanWang

2016-10-11

A method and apparatus for cooling hot gas streams in the temperature range 800.degree. C. to 1600.degree. C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers. Higher process efficiencies can be realized as the invention can handle hot syngas from various types of gasifiers without the need for a less efficient precooling step.

The physics of highly charged heavy ions revealed by storage/cooler rings

International Nuclear Information System (INIS)

Mokler, P.H.; Stoehlker, T.

1996-01-01

With the successful commissioning of storage and cooler rings for bright beams of very heavy ions near the threshold of the last decade of this century, not only did a prosperous development in heavy ion accelerator technology come to its present summit, but also fundamental fields in heavy ion physics were opened widely for exciting explorations. Now, essential aspects in this area are accessible, aspects one only dared to dream of another decade ago. In the meantime, great progress already has been made in the fundamental physics in this field. This is particularly true for achievements in the atomic physics of highly charged heavy ions. In this chapter, we present a review of the current advances in this rapidly developing field. There are two general domains to be considered in the atomic physics of highly charged heavy ions: the fields of collisions and of atomic structure. Both aspects have to be explored equally, as they are strongly interconnected. One has to investigate the interaction processes to know, for instance, the population of excited states to help answer questions on the atomic structure; and conversely, one has to know the structure to understand the interactions. In both the fields, fundamental principles can be studied uniquely. This is in particular true for the heaviest ion species with only a few- or even zero-electrons left. 140 refs., 39 figs

Meteorological, stream-discharge, and water-quality data for water year 1992 from two basins in Central Nevada

International Nuclear Information System (INIS)

McKinley, P.W.; Oliver, T.A.

1995-01-01

The US Geological Survey, in cooperation with the US Department of Energy, is studying Yucca Mountain, Nevada, as a potential repository for high level nuclear waste. As part of the Yucca Mountain Site Project, the analog recharge study is providing data for the evaluation of recharge to the Yucca Mountain ground-water system given a cooler and wetter climate than currently exists. The current and climatic conditions are favorable to the isolation of radioactive waste. Because waste isolation from the accessible environment for 10,000 years is necessary, climatic change and the potential for increased ground-water recharge need to be considered as part of the characterization of the potential repository. Therefore, two small basins, measuring less than 2 square miles, were studied to determine the volume of precipitation available for recharge to ground water. The semiarid 3-Springs Basin is located to the east of Kawich Peak in the Kawich Range east of Tonopah, Nevada. Stewart Basin is a subalpine drainage basin north of Arc Dome in the Toiyabe Range north of Tonopah, Nevada. The purpose of this publication is to make available the meteorological, stream-discharge, and water-quality data collected during the study. Meteorological data collected include air temperature, soil temperature, solar radiation, and relative humidity. Stream-discharge data were collected from the surface-water outlet of each basin. Water-quality data are chemical analyses of water samples collected from surface- and ground-water sources. Each basin has a meteorological station located in the lower and upper reaches of the basin. Hydrologic records include stream-discharge and water-quality data from the lower meteorological site and water-quality data from springs within the basins

Metabolic rates and tissue composition of the coral Pocillopora verrucosa over 12 latitudes in the Red Sea characterized by strong temperature and nutrient gradient, supplement to: Sawall, Yvonne; Al-Sofyani, A; Hohn, S; Banguera-Hinestroza, E; Voolstra, Christian R; Wahl, Martin (2015): Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming. Scientific Reports, 5, 8940

KAUST Repository

Sawall, Yvonne; Al-Sofyani, A; Hohn, S; Banguera-Hinestroza, E; Voolstra, Christian R.; Wahl, Martin

2015-01-01

Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo

Sump water usability analysis following LB LOCA of CANDU 6 reactor

Energy Technology Data Exchange (ETDEWEB)

Jang, M.S. [Nuclear Engineering Service & Solution, Daejeon (Korea, Republic of); Kim, S.M. [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of); Moon, B.J.; Kim, S.R. [Nuclear Engineering Service & Solution, Daejeon (Korea, Republic of)

2014-07-01

This paper focused on the analysis of sump water usability as a source for low pressure emergency core cooling injection in CANDU 6 for large break loss of coolant accident, using GOTHIC-IST code. For a long term cooling, the operation of low pressure recirculation using an emergency core cooling pump is required. To operate an emergency core cooling pump, the net positive suction head of the pump should be satisfied. The maximum permissible temperature of sump water to meet the net positive suction head of an emergency core cooling pump is 87.73{sup o}C. In this study, the temperature and the level of sump water were monitored for the large break loss of coolant accident with malfunction of spray system and local air coolers. For all considered accident cases, the temperature of containment basement water was analyzed to be lower than 87.73{sup o}C and it was possible to operate the low pressure recirculation using an emergency core cooling pump for the most restricted scenario. (author)

Radiofrequency quadrupole-based beam cooler and buncher for the CANREB project at TRIUMF

Science.gov (United States)

Barquest, Brad; Pearson, Matt; Ames, Friedhelm; Dilling, Jens; Gwinner, Gerald; Kanungo, Rituparna; Kruecken, Reiner

2016-09-01

A new radiofrequency quadrupole-based ion beam cooler and buncher (BCB) and pulsed drift tube (PDT) have been designed as part of the CANREB project at TRIUMF. The BCB is designed to accept continuous 60 keV rare isotope beams from the ARIEL or ISAC production targets and efficiently deliver low-emittance, bunched beams of up to 107 ions per bunch to an electron beam ion source (EBIS) to charge-breed the bunch for post-acceleration. The PDT will adjust the energy of the bunched beam from 60 keV to 10-14 keV for injection into the EBIS. The injection energy is determined by the acceptance of the post-accelerating RFQ. The design of the BCB is nearing completion, and fabrication and assembly effort will proceed shortly. In addition, a PDT prototype is under development to test that the design concept satisfies the voltage and switching time requirements. Design features of the BCB and PDT will be discussed, and an update on BCB assembly and PDT testing progress will be presented. CANREB is funded by CFI, NSRIT, Manitoba Research and Innovation Fund, AAPS, Saint Mary's U, U of Manitoba and TRIUMF. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

Multi Channels PWM Controller for Thermoelectric Cooler Using a Programmable Logic Device and Lab-Windows CVI

Directory of Open Access Journals (Sweden)

Eli FLAXER

2008-09-01

Full Text Available We present a complete design of a multi channels PID controller for Thermoelectric Cooler (TEC using a pulse width modulation (PWM technique implemented by a dedicated programmable logic device (PLD programmed by VHDL. The PID control loop is implemented by software written by National Instrument Lab-Windows CVI. Due to the fact that the implementation is by a VHDL and PLD the design is modular, as a result, the circuit is very compact in size and very low cost as compared to any commercial product. In addition, since the control loop is implemented by software running on a personal computer (PC using a C language, it is easy to adjust the controller to various environmental conditions and for a width range of sensors like: a thermo couple (TC, thermistor, resistance temperature detectors (RTD etc. We demonstrate the performance of this circuit as a controller for a small incubator using thermistor as the temperature sensor.

Modeling of hydrogen stratification in a pressurized water reactor containment with the contain computer code

International Nuclear Information System (INIS)

Kljenak, I.; Skerlavaj, A.; Parzer, I.

1999-01-01

Hydrogen distribution during a severe accident in a nuclear power plant with a two-loop Westinghouse-type pressurized water reactor was simulated with the CONTAIN computer code. The accidents is initiated by a large-break loss-of-coolant accident which is nit successfully mitigated by the action of the emergency core cooling system. Cases with and without successful actuation of spray systems and fan coolers were considered. The simulations predicted hydrogen stratification within the containment main compartment with intensive hydrogen mixing in the containment dome region. Pressure and temperature responses were analyzed as well.(author)

Methodology on sizing and selecting thermoelectric cooler from different TEC manufacturers in cooling system design

International Nuclear Information System (INIS)

Tan, F.L.; Fok, S.C.

2008-01-01

The search and selection for a suitable thermoelectric cooler (TEC) to optimize a cooling system design can be a tedious task as there are many product ranges from several TEC manufacturers. Although the manufacturers do provide proprietary manuals or electronic search facilities for their products, the process is still cumbersome as these facilities are incompatible. The electronic facilities often have different user interfaces and functionalities, while the manual facilities have different presentations of the performance characteristics. This paper presents a methodology to assist the designer to size and select the TECs from different manufacturers. The approach will allow designers to find quickly and to evaluate the devices from different TEC manufacturers. Based on the approach, the article introduces a new operational framework for an Internet based thermoelectric cooling system design process that would promote the interaction and collaboration between the designers and TEC manufacturers. It is hoped that this work would be useful for the advancement of future tools to assist designers to develop, analyze and optimize thermoelectric cooling system design in minimal time using the latest TECs available on the market

A novel magnetic suspension cum linear actuator system for satellite cryo coolers

International Nuclear Information System (INIS)

Sivadasan, K.K.

1994-01-01

Stirling cycle cryogenic coolers have been widely used for device cooling in satellites. Various types of magnetic bearings and linear actuators find application in such systems. The most widely used configurations have two-axis-radially-active suspension stations placed at either ends of a reciprocating shaft in the compression and expansion sections. Separate or integral liner motors are provided in each section for axial shaft movement. It may be noted that such configurations are rather complicated and less reliable because of the presence of numerous electro-mechanical components, sensors and electronic servo channels. In this paper, a simple and reliable scheme is suggested which axially stabilizes and linearly perturbs the piston so that the need for a separate motor for axial actuation can be totally dispensed with. The piston is radially supported by passive repulsive bearings. In the axial direction, a servo actuator ''balances'' the piston and also actuates it bi-directionally. Implemented of this ''bearing cum motor theme,'' reduces the number of electromechanical and electronic components required to operate the system and hence minimizes the chances of system failure. Apart from this, the system's power consumption is reduced and efficiency is improved as electrical heating losses caused by quiescent-operating currents are removed and electromagnetic losses on the moving parts are minimized. The necessary system parameters have been derived using finite element analysis techniques. Finally, the proposed design is validated by computer-aided system simulation

Modelling contrasting responses of wetland productivity to changes in water table depth

Directory of Open Access Journals (Sweden)

R. F. Grant

2012-11-01

Full Text Available Responses of wetland productivity to changes in water table depth (WTD are controlled by complex interactions among several soil and plant processes, and hence are site-specific rather than general in nature. Hydrological controls on wetland productivity were studied by representing these interactions in connected hummock and hollow sites in the ecosystem model ecosys, and by testing CO₂ and energy fluxes from the model with those measured by eddy covariance (EC during years with contrasting WTD in a shrub fen at Lost Creek, WI. Modelled interactions among coupled processes for O₂ transfer, O₂ uptake, C oxidation, N mineralization, N uptake and C fixation by diverse microbial, root and mycorrhizal populations enabled the model to simulate complex responses of CO₂ exchange to changes in WTD that depended on the WTD at which change was occurring. At the site scale, greater WTD caused the model to simulate greater CO₂ influxes and effluxes over hummocks vs. hollows, as has been found at field sites. At the landscape scale, greater WTD caused the model to simulate greater diurnal CO₂ influxes and effluxes under cooler weather when water tables were shallow, but also smaller diurnal CO₂ influxes and effluxes under warmer weather when water tables were deeper, as was also apparent in the EC flux measurements. At an annual time scale, these diurnal responses to WTD in the model caused lower net primary productivity (NPP and heterotrophic respiration (R_h, but higher net ecosystem productivity (NEP = NPP − R_h, to be simulated in a cooler year with a shallower water table than in a warmer year with a deeper one. This difference in NEP was consistent with those estimated from gap-filled EC fluxes in years with different water tables at Lost Creek and at similar boreal fens elsewhere. In sensitivity tests of the model, annual NEP

Solar heater/cooler for mass market

Science.gov (United States)

1981-01-01

Report describes project to design, build, and test simple and affordable solar systems. Four combinations of heating, cooling, and domestic hot water supply systems were developed and installed. Test sites, plan for systems and components, and performance are discussed; text is complimented by detailed drawings and test data.

Cyclonic entrainment of preconditioned shelf waters into a frontal eddy

Science.gov (United States)

Everett, J. D.; Macdonald, H.; Baird, M. E.; Humphries, J.; Roughan, M.; Suthers, I. M.

2015-02-01

The volume transport of nutrient-rich continental shelf water into a cyclonic frontal eddy (entrainment) was examined from satellite observations, a Slocum glider and numerical simulation outputs. Within the frontal eddy, parcels of water with temperature/salinity signatures of the continental shelf (18-19°C and >35.5, respectively) were recorded. The distribution of patches of shelf water observed within the eddy was consistent with the spiral pattern shown within the numerical simulations. A numerical dye tracer experiment showed that the surface waters (≤50 m depth) of the frontal eddy are almost entirely (≥95%) shelf waters. Particle tracking experiments showed that water was drawn into the eddy from over 4° of latitude (30-34.5°S). Consistent with the glider observations, the modeled particles entrained into the eddy sunk relative to their initial position. Particles released south of 33°S, where the waters are cooler and denser, sunk 34 m deeper than their release position. Distance to the shelf was a critical factor in determining the volume of shelf water entrained into the eddy. Entrainment reduced to 0.23 Sv when the eddy was furthest from the shelf, compared to 0.61 Sv when the eddy was within 10 km of the shelf. From a biological perspective, quantifying the entrainment of shelf water into frontal eddies is important, as it is thought to play a significant role in providing an offshore nursery habitat for coastally spawned larval fish.

Elevated service water temperature systems analysis for a nuclear power plant

International Nuclear Information System (INIS)

Lewis, T.; Hurt, W.

1992-01-01

This paper describes analyses performed to support the evaluation of the effects of elevated Service Water (SW) temperatures on the operation of a Pressurized Water Reactor. The purpose of the analyses is to provide justification of continued plant operation with SW temperatures up to 5 degrees F (3 degrees C) above the original temperature design limit. The study involved evaluation of the following major components or plant transients: Containment Design Basis Accident (DBA), Emergency Diesel Generator (EDG), Plant Cooldown, Engineered Safety Feature (ESF) Room Coolers, Engineered Safety Feature Pumps, and Assessment for Impact on Normal Operation. The principal objective was related to raising the design maximum temperature of the SW system from 95 degrees F (35 degrees C) to 100 degrees F (38 degrees C). since the Service Water system is safety related, an serves a plant during both normal and design basis conditions, a wide variety of components must be analyzed under various operating modes. The evaluation of systems and components affected by elevated SW temperature is presented, along with conclusions

Mediating Water Temperature Increases Due to Livestock and Global Change in High Elevation Meadow Streams of the Golden Trout Wilderness

Science.gov (United States)

Nusslé, Sébastien; Matthews, Kathleen R.; Carlson, Stephanie M.

2015-01-01

Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measured riparian vegetation and monitored water temperature in three meadow streams between 2008 and 2013, including two “resting” meadows and one meadow that is partially grazed. All three meadows have been subject to grazing by cattle and sheep since the 1800s and their streams are home to the imperiled California golden trout (Oncorhynchus mykiss aguabonita). In 1991, a livestock exclosure was constructed in one of the meadows (Mulkey), leaving a portion of stream ungrazed to minimize the negative effects of cattle. In 2001, cattle were removed completely from two other meadows (Big Whitney and Ramshaw), which have been in a “resting” state since that time. Inside the livestock exclosure in Mulkey, we found that riverbank vegetation was both larger and denser than outside the exclosure where cattle were present, resulting in more shaded waters and cooler maximal temperatures inside the exclosure. In addition, between meadows comparisons showed that water temperatures were cooler in the ungrazed meadows compared to the grazed area in the partially grazed meadow. Finally, we found that predicted temperatures under different global warming scenarios were likely to be higher in presence of livestock grazing. Our results highlight that land use can interact with climate change to worsen the local thermal conditions for taxa on the edge and that protecting riparian vegetation is likely to increase the resiliency of these ecosystems to climate change. PMID:26565706

Influence of fine water droplets to temperature and humidity

Science.gov (United States)

Hafidzal, M. H. M.; Hamzah, A.; Manaf, M. Z. A.; Saadun, M. N. A.; Zakaria, M. S.; Roslizar, A.; Jumaidin, R.

2015-05-01

Excessively dry air can cause dry skin, dry eyes and exacerbation of medical conditions. Therefore, many researches have been done in order to increase humidity in our environment. One of the ways is by using water droplets. Nowadays, it is well known in market stand fan equipped with water mister in order to increase the humidity of certain area. In this study, the same concept is applied to the ceiling fan. This study uses a model that combines a humidifier which functions as cooler, ceiling fan and scaled down model of house. The objective of this study is to analyze the influence of ceiling fan humidifier to the temperature and humidity in a house. The mechanism of this small model uses batteries as the power source, connected to the fan and the humidifier. The small water tank's function is to store and supply water to the humidifier. The humidifier is used to cool the room by changing water phase to fine water droplets. Fine water droplets are created from mechanism of the humidifier, which is by increasing the kinetic energy of water molecule using high frequency vibration that overcome the holding force between water molecules. Thus, the molecule of water will change to state of gas or mist. The fan is used to spread out the mist of water to surrounding of the room in order to enhance the humidity. Thermocouple and humidity meter are used to measure temperature and humidity in some period of times. The result shows that humidity increases and temperature decreases with time. This application of water droplet can be applied in the vehicles and engine in order to decrease the temperature.

Solar chimney integrated with passive evaporative cooler applied on glazing surfaces

International Nuclear Information System (INIS)

Al Touma, Albert; Ghali, Kamel; Ghaddar, Nesreen; Ismail, Nagham

2016-01-01

This study investigates the performance of a hybrid system applied on glazing surfaces for reducing the space cooling load and radiation asymmetry. The proposed system combines the principles of passive evaporative cooling with the natural buoyant flow in solar chimneys to entrain outdoor air and attenuate the window surface temperature. A predictive heat and mass transport model combining the evaporative cooler, glazing section, solar chimney and an office space is developed to study the system performance in harshly hot climates. The developed model was validated through experiments conducted in a twin climatic chamber for given ambient temperature, humidity, and solar radiation conditions. Good agreement was found between the measured and the predicted window temperatures and space loads at maximum discrepancy lower than 4.3%. The proposed system is applied to a typical office space to analyze its effectiveness in reducing the window temperature, the space load and radiation asymmetry, while maintaining the indoor comfort conditions. Results have shown that the system is reduced the space load by −19.8% and attenuated the radiation asymmetry significantly for office spaces having window-to-wall ratio of 40% in climate of Riyadh, KSA. The system performance diminished when applied in locations suffering from humid weather climates. - Highlights: • A passive evaporative-cooled solar chimney system is introduced to decrease window temperature. • A mathematical model is developed of the system to predict induce air flow and window surface temperature. • The model is validated with experiments in twin room climatic chamber and using artificial solar lamps. • The system reduces window maximum temperature by 5 °C in the hot dry climate of Riyadh, KSA. • It reduced the space load by 19.4% for office spaces at window-to-wall ratio of 40% in Riyadh, KSA.

Comparative study between a ceramic evaporative cooler (CEC) and an air-source heat pump applied to a dwelling in Spain

Energy Technology Data Exchange (ETDEWEB)

Martinez, Francisco Javier Rey; Gomez, Eloy Velasco; Gonzalez, Ana Tejero [University of Valladolid, Dept. of Energy and Fluidmechanics, School of Engineering, Paseo del Cauce s/n, C. P. 47011, Valladolid (Spain); Murrieta, Fernando Enrique Flores [University of Quintana Roo, Science and Engineering Division, Blvd. Bahia s/n esq. I. Comonfort. Col. Del Bosque. 77019, Chetumal, Quintana Roo (Mexico)

2010-10-15

The study described in this paper aims to evaluate comparatively the interest of an implementation of a ceramic evaporative cooler (CEC) compared to the use of a conventional device such as an air-source heat pump. This comparison is presented in three closely related ways: energy consumption, environmental impact and economic costs. This analysis is based on the hypothetical cooling of a specific room in a dwelling in six Spanish cities, each characterised by a different climate. The behaviour of the CEC in each climate is determined experimentally, reproducing the typical air conditions by an air-treatment unit. The total cooling demand in each city during the summer months is obtained from the data of the thermal load evolution in the room, provided by thermal load calculation software. (author)

Perceptions about availability and adequacy of drinking water in a large California school district.

Science.gov (United States)

Patel, Anisha I; Bogart, Laura M; Uyeda, Kimberly E; Rabin, Alexa; Schuster, Mark A

2010-03-01

Concerns about the influence of sugar-sweetened beverage consumption on obesity have led experts to recommend that water be freely available in schools. We explored perceptions about the adequacy of drinking water provision in a large California school district to develop policies and programs to encourage student water consumption. From March to September 2007, we used semistructured interviews to ask 26 California key stakeholders - including school administrators and staff, health and nutrition agency representatives, and families - about school drinking water accessibility; attitudes about, facilitators of, and barriers to drinking water provision; and ideas for increasing water consumption. Interviews were analyzed to determine common themes. Although stakeholders said that water was available from school drinking fountains, they expressed concerns about the appeal, taste, appearance, and safety of fountain water and worried about the affordability and environmental effect of bottled water sold in schools. Stakeholders supported efforts to improve free drinking water availability in schools, but perceived barriers (eg, cost) and mistaken beliefs that regulations and beverage contracts prohibit serving free water may prevent schools from doing so. Some schools provide water through cold-filtered water dispensers and self-serve water coolers. This is the first study to explore stakeholder perceptions about the adequacy of drinking water in US schools. Although limited in scope, our study suggests that water available in at least some schools may be inadequate. Collaborative efforts among schools, communities, and policy makers are needed to improve school drinking water provision.

Modelling of Disinfection by-products formation via UV irradiation of the water from Tajan River (source water for Sari drinking water, Iran

Directory of Open Access Journals (Sweden)

Allahbakhsh Javid

2013-11-01

Full Text Available Background & Aims of the Study Irradiation with ultraviolet light (UV is used for the disinfection of bacterial contaminants in the production of potable water. The main objective of the study was to investigate and model Disinfection By-Products (DBPs formation due to the UV Irradiation of the Tajan River water under different Irradiation conditions. Materials & Methods:  Water samples were collected throughout September 2011 to August 2013. Transportation of the sample to the laboratory was done on ice in a cooler, and physiochemical analysis was conducted immediately within one day. Dissolved organic carbon (DOC was determined by a TOC analyzer. Irradiation experiments were conducted in a series of 25 mL glass serum bottles with Teflon septa. The present study adopts an orthogonal design. The design involved irradiation with UV at a UV/DOC ratio of 0.5–3.0 and incubating (headspace-free storage for 5–25 sec. A 1 mM phosphate buffer maintained the pH at 6, 7, or 8 respectively, and an incubator maintained the temperature (Temp at 15, 20, or 25 °C respectively. The development of empirical models for DBPs formation used a multivariate regression procedure (stepwise which applied the SPSS System for Windows (Version 16.0. Results:  The results showed that the total DBPs formation ranged between 12.3 and 67.4 mg/l and that control of the levels was primarily due to the reaction time and the dissolved organic carbon level (DOC in the water. Conclusions:  Reaction time and level of DOC concentrations in water exerted a dominant influence on the formation of DBPs during the UV irradiation of water from the Tajan River. The relationships between the measured and predicted values were satisfactory with R 2 values ranging from 0.89 (for Octanal–0.92 (for Formaldehydes. The DOC level in water is the key factor in controlling DBPs formation.

Plate heat exchangers in air conditioning applications. Development of air-coolers, air-heaters and air-conditioning units with low pressure loss. Plattenwaermetauscher in raumlufttechnischen Anlagen. Entwicklung stroemungsoptimierter Luftkuehler, Lufterhitzer und Klimageraete

Energy Technology Data Exchange (ETDEWEB)

Bach, H; Diemer, R; Eisenmann, G; Goettling, D; Madjidi, M

1989-08-01

To prepare the development of a water to air plate heat exchanger the state of the art, i.e. the technological knowhow and the design basis are given. The concept and ideas are presented which lead to a slightly wavy plate. Furthermore an exemplary design of a plate heat exchanger and an air-conditioning unit is described and finally the application of plate heat exchangers as direct evaporators and the potential icing problems are investigated. Comparing measured and calculated data shows that the performance of plates with plane surfaces can be predicted fairly well by the presented design methods. The performance of plates with strongly wavy surface however has to be measured. Optimization calculations yield to an air gap of slightly over 4 mm. Comparison with an air-conditioning unit demonstrates that the strongest advantage is for the air cooler (one third of the pressure loss) that a new concept of an air-conditioning unit has lower losses in the fan unit and that it does not need an eliminator. This results in half the volume for the new unit, in a pressure drop of 88%, fan power of 90% and fan revolutions of 50%. (orig./GL).

Device for district heating with utilization of waste heat from power plants

International Nuclear Information System (INIS)

Korek, J.

1976-01-01

In order to utilize the waste heat developing in power plants - especially in nuclear power plants - the author suggests to lead the waste heat of the coolers for oil (which the bearings are lubricated with), hydrogen (which serves for the stator rotor-cooling), and the stator cooling water to the circulating district heating water and to arrange these heat exchangers one behind another or parallel to each other in the water circuit of the district heating system. The oil cooler of the engine transformer is also connected with the circulation of the district heating water. The runback water of the district heating network could thus be heated from approx. 40 0 C up to 65 0 C. (UA) [de

Operating experience feedback report: Service water system failures and degradations: Volume 3

International Nuclear Information System (INIS)

Lam, P.; Leeds, E.

1988-11-01

A comprehensive review and evaluation of service water system failures and degradations observed in operating events in light water reactors from 1980 to 1987 has been conducted. The review and evaluation focused on the identification of causes of system failures and degradations, the adequacy of corrective actions implemented and planned, and the safety significance of the operating events. The results of this review and evaluation indicate that the service water system failures and degradations have significant safety implications. These system failures and degradations are attributable to a great variety of causes, and have adverse impact on a large number of safety-related systems and components which are required to mitigate reactor accidents. Specifically, the causes of failures and degradations include various fouling mechanisms (sediment deposition, biofouling, corrosion and erosion, pipe coating failure, calcium carbonate, foreign material and debris intrusion); single failures and other design deficiencies; flooding; multiple equipment failures; personnel and procedural errors; and seismic deficiencies. Systems and components adversely impacted by a service water system failure or degradation include the component cooling water system, emergency diesel generators, emergency core cooling system pumps and heat exchangers, the residual heat removal system, containment spray and fan coolers, control room chillers, and reactor building cooling units. 44 refs., 10 figs., 5 tabs

Sensitivity and Design of a Transcritical CO2 Cooling and Heating System

DEFF Research Database (Denmark)

Nguyen, Chan; Veje, Christian; Willatzen, Morten

2012-01-01

This paper presents a theoretical design study of a transcritical CO2 heat pump system for simultaneous cooling and heating. The heat pump model consists of the components: compressor, internal heat exchanger, valve, evaporator and gas cooler. The evaporator and the gas cooler are both water...... exchangers. The results show that COP is particular sensitive to the pinch temperature in the gas cooler and to the compressor isentropic efficiency but not to pressure loss. However it is found that the heat exchanger weights are very sensitive to pressure loss. The thermodynamic and heat exchanger models...

Water and sediment temperatures at mussel beds in the upper Mississippi River basin

Science.gov (United States)

Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

2013-01-01

Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually cause mortality in laboratory studies. These data suggest that elevated water temperatures resulting from global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

Economic and thermal feasibility of multi stage flash desalination plant with brine–feed mixing and cooling

International Nuclear Information System (INIS)

Alhazmy, Majed M.

2014-01-01

Improving the performance of MSF (multi stage flash) desalination plants is a major challenge for desalination industry. High feed temperature in summer shortens the evaporation range of MSF plants and limits their yield. Installing a cooler at the feed intake expands the evaporation range of MSF plants and increases their yield. Adding a cooler and a mixing chamber increases the capital and operational costs of MSF plants. This paper presents thermal and economic analysis of installing a feed cooler at the plant intake. The profit of selling the additionally produced water must cover the cost of the cooling system. The selling prices for a reasonable breakeven depend on the selected cooling temperature. The cost of installing coolers capable of maintaining feed–brine mixture temperatures of 18–20 °C shows breakeven selling prices of 0.5–0.9 $/m 3 . These prices fall within the current range of potable water selling prices. - Highlights: • Thermo-economic analysis for MSF plant with brine mixing and cooling is presented. • Analysis is based on first and second laws of thermodynamics. • The profit gained from producing additional water covers the cooling cost. • The suggested modification is a promising technique for plants in hot climates

Deuterium concentration deterioration in feed synthesis gas from ammonia plant to heavy water plant (Preprint No. ED-5)

International Nuclear Information System (INIS)

Sah, A.K.

1989-04-01

Heavy Water Plant (Thal) is designed for 110 T/ Year capacity (55 T/Year each stream), with inlet deuterium concentration of feed synthesis gas at 115 ppm and depleted to 15 ppm. During first start up of plant the inlet concentration to feed synthesis gas was about 97 ppm. At that time the rich condensate recirculation was not there. To make the effective recirculation of deuterium rich condensate and minimum posssible losses some modifications were carried out in ammonia plant. Major ones are: (i)Demineralised (DM) water export for heavy water plant and urea plant which was having deuterium rich DM water connection was connected with DM water of urea plant which is not rich in deuterium, (ii)Sample cooler pump suction was connected with raw water, (iii)Ammonia plant line No.II condensate stripper was rectified during annual shut down to avoid excessive steam venting from its top and other draining, and (iv)Stripper condensate directly connected to make up water bypassing open settler to avoid evaporation and diffusion losses. With these modifications the deuterium concentration in feed synthesis gas improved to about 105 ppm. To improve it to 115 ppm, further modifications are suggested. (author). 5 figs

Isotopic and chemical composition of water and steam discharges from volcanic-magmatic-hydrothermal systems of the Guanacaste Geothermal Province, Costa Rica

Energy Technology Data Exchange (ETDEWEB)

Giggenbach, W.F. (Department of Scientific and Industrial Research, Petone (New Zealand). Chemistry Div.); Soto, R.C. (Instituto Costarricense de Electricidad, San Jose (Costa Rica))

1992-07-01

The Guanacaste Geothermal Province encompasses three major geothermal systems, each centered on its respective volcanic structure: Rincon de la Vieja to the NW, Miravalles in the center and Tenorio to the SE. Each shows corresponding sets of surface manifestations: vapor discharges from fumaroles and steam-heated pools at altitudes >500 m; lower temperature SO{sub 4}-Cl springs on the lower slopes of the respective volcano; and cooler neutral Cl springs to the S of the volcanic chain, at altitudes <500 m. The production of HCO{sub 3}-rich waters is limited to a narrow belt stretching to the S of Miravalles volcano. Chemical and isotopic evidence suggests that the neutral Cl waters, also discharged from deep wells, are derived from a more primitive Cl-SO{sub 4} water formed by transfer of readily mobilised, originally magmatic constituents to deeply circulating groundwater. (author).

Development of maintenance procedure for plate type heat exchanger taking into account preventing radioactive contamination

International Nuclear Information System (INIS)

Terai, Kensuke; Someki, Hiroyuki; Ueda, Yuya

2017-01-01

In Japanese pressurized water reactors (PWR), heat loads of spent fuel pools (SFP) is increasing due to rising spent fuels and use of mixed oxide (MOX) fuels. Therefore, SFP cooling capacities are necessary to be enhanced, and replacement of SFP coolers or installation of additional coolers is needed. On the other hand, installation spaces of SFP coolers are limited in existing buildings. Therefore, plate type heat exchangers which can be designed to be compact because of the high heat efficiency have often been adopted for SFP coolers instead of shell and tube type heat exchangers in general use. Plate type heat exchangers have to be overhauled periodically for inspection and gasket replacement. However, in plate type SFP coolers, radioactive SFP water and non-radioactive component cooling water (CCW) alternately run through between each plate. Thus there is a concern that the CCW system may be contaminated by radioactive materials from the SFP water during overhaul of the SFP cooler. In order to solve this problem, we have developed the maintenance procedure of the plate type SFP coolers to prevent CCW side contamination by coating the contaminated surfaces with strippable paint prior to disassembly. Before applying this developed maintenance procedure to actual equipment, we have performed the following verification tests. (1) Confirmation of fundamental characteristics for strippable paint. Firstly, we selected both water-based and solvent-based strippable paints. Secondly, we tested and confirmed the detachability and the drying time of the selected strippable paints respectively. Moreover we also confirmed that the selected strippable paints are appropriate materials from the viewpoint of chemical composition restriction of consumable materials used in nuclear power plant. (2) Confirmation of workability for paint filling, drying and peeling off. The strippable paints need to be peeled off after filling into plate type heat exchanger and draining

A passive decay heat removal system for LWRs based on air cooling

Energy Technology Data Exchange (ETDEWEB)

Mochizuki, Hiroyasu, E-mail: mochizki@u-fukui.ac.jp [Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan); Yano, Takahiro [Graduate School of Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan)

2015-05-15

Highlights: • A passive decay heat removal system for LWRs is discussed. • An air cooler model which condenses steam is developed. • The decay heat can be removed by air coolers with forced convection. • The dimensions of the air cooler are proposed. - Abstract: The present paper describes the capability of an air cooling system (ACS) to remove decay heat from a core of LWR such as an advanced boiling water reactor (ABWR) and a pressurized water reactor (PWR). The motivation of the present research is the Fukushima severe accident (SA) on 11 March 2011. Since emergency cooling systems using electricity were not available due to station blackout (SBO) and malfunctions, many engineers might understand that water cooling was not completely reliable. Therefore, a passive decay heat removal (DHR) system would be proposed in order to prevent such an SA under the conditions of an SBO event. The plant behaviors during the SBO are calculated using the system code NETFLOW++ for the ABWR and PWR with the ACS. Two types of air coolers (ACs) are applied for the ABWR, i.e., a steam condensing air cooler (SCAC) of which intake for heat transfer tubes is provided in the steam region, and single-phase type of which intake is provided in the water region. The DHR characteristics are calculated under the conditions of the forced air circulation and also the natural air convection. As a result of the calculations, the decay heat can be removed safely by the reasonably sized ACS when heat transfer tubes are cooled with the forced air circulation. The heat removal rate per one finned heat transfer tube is evaluated as a function of air flow rate. The heat removal rate increases as a function of the air flow rate.

Developments for the HITRAP cooler trap and mass measurements around A = 96 at SHIPTRAP

Energy Technology Data Exchange (ETDEWEB)

Koszudowski, Stephen

2009-07-08

The HITRAP (Highly charged Ions Trap) facility is currently being set up and commissioned at GSI in Darmstadt. It will provide bunches of 10{sup 5} heavy highly-charged ions, for example hydrogen-like uranium (U{sup 91+}), to high-precision atomic physics experiments. The ions are produced by the GSI accelerator complex and decelerated to 4 MeV/u in the Experimental Storage Ring. Then the ions are decelerated by a two-step linear decelerator down to 6 keV/u. The first deceleration step down to 500 keV/u was successfully commissioned. The decelerated ions are injected into a Penning trap (the Cooler Trap), where they are cooled to 4 K by electron and resistive cooling. Resonant circuits for non-destructive detection and the resistive cooling of the trapped particles were designed and tested. The time control of the trap-cycle (trapping, cooling, extraction) with a time resolution of 25 ns was implemented into the control system CS. CS is also used at the mass measurement Penning trap SHIPTRAP, where the new time control is successfully operated. SHIPTRAP measures radioactive ions stemming from fusion evaporation reactions at the velocity filter SHIP. The masses of 9 nuclides ({sup 93,94,95}Technetium, {sup 94,96}Ruthenium, {sup 95,96,97,98}Rhodium) near the line of stability were precisely measured and compared with the Atomic Mass Evaluation. The detection of isomeric states with the present SHIPTRAP set-up was studied. (orig.)

Developments for the HITRAP cooler trap and mass measurements around A = 96 at SHIPTRAP

International Nuclear Information System (INIS)

Koszudowski, Stephen

2009-01-01

The HITRAP (Highly charged Ions Trap) facility is currently being set up and commissioned at GSI in Darmstadt. It will provide bunches of 10 5 heavy highly-charged ions, for example hydrogen-like uranium (U 91+ ), to high-precision atomic physics experiments. The ions are produced by the GSI accelerator complex and decelerated to 4 MeV/u in the Experimental Storage Ring. Then the ions are decelerated by a two-step linear decelerator down to 6 keV/u. The first deceleration step down to 500 keV/u was successfully commissioned. The decelerated ions are injected into a Penning trap (the Cooler Trap), where they are cooled to 4 K by electron and resistive cooling. Resonant circuits for non-destructive detection and the resistive cooling of the trapped particles were designed and tested. The time control of the trap-cycle (trapping, cooling, extraction) with a time resolution of 25 ns was implemented into the control system CS. CS is also used at the mass measurement Penning trap SHIPTRAP, where the new time control is successfully operated. SHIPTRAP measures radioactive ions stemming from fusion evaporation reactions at the velocity filter SHIP. The masses of 9 nuclides ( 93,94,95 Technetium, 94,96 Ruthenium, 95,96,97,98 Rhodium) near the line of stability were precisely measured and compared with the Atomic Mass Evaluation. The detection of isomeric states with the present SHIPTRAP set-up was studied. (orig.)

3D Analysis of Cooling Performance with Loss of Offsite Power Using GOTHIC Code

International Nuclear Information System (INIS)

Oh, Kye Min; Heo, Gyun Young; Na, In Sik; Choi, Yu Jung

2010-01-01

GOTHIC code enables to analyze one-dimensional or multi-dimensional problems for evaluating the cooling performance of loss of offsite power. The conventional GOTHIC code analysis performs heat transfer between plant containment and the outside of the fan cooler tubes by modeling each of fan cooler part model and component cooling water inside tube each to analyze boiling probability. In this paper, we suggest a way which reduces the multi-procedure of the cooling performance with loss of offsite power or the heat transfer states with complex geometrical structure to a single-procedure and verify the applicability of the heat transfer differences from the containment atmosphere humidity changes by the multi-nodes which component cooling water of tube or air of Reactor Containment Fan Cooler in the containment, otherwise the component model uses only one node

Experimental study on solar desiccant cooling system. 2nd Report; Taiyonetsu kudo desiccant cooling system no jikkenteki kento. 2

Energy Technology Data Exchange (ETDEWEB)

Tanaka, H; Funato, H [Fukuoka Institute of Technology, Fukuoka (Japan); Kuma, T [Seibu Giken Co. Ltd., Fukuoka (Japan)

1996-10-27

Study has been made about a desiccant cleaning system using solar heated water for regenerating the dehumidifier. A dehumidifier and evaporation coolers are combined to attain a synergistic effect in dehumidifying and cooling the air in the house. The simultaneous control of humidity and temperature, however, is quite difficult. Under the circumstances, an evaporation cooler was removed from the outdoor air intake side, to leave a humidifier alone for the control of humidity only. In addition, the length of the dehumidifier was reduced into half for saving fan driving power and for downscaling the model. With only one evaporation cooler in operation that is installed at the exhaust side, the cooling effect is diminished by half. For dealing with the situation, ultrasonic atomization is performed at the exhaust side evaporation cooler for the improvement of the air cooling effect for the next sensible heat exchanger (intake side). The return air is heated by the solar heater water (approximately 60{degree}C hot), regenerates the dehumidifier, and then exhausted. The atomization process elevates the cooling effect, and the resultant cooling effect was as high as that expected from a 2-cooler setup. The dehumidification effect, however, lowers a little. Exclusion of the atomization process will enhance the dehumidification effect, but will reduce the cooling effect as well. 3 refs., 8 figs., 3 tabs.

Ultrasonically facilitated adsorption of an azo dye onto nanostructures obtained from cellulosic wastes of broom and cooler straw.

Science.gov (United States)

Safari, Mahdi; Khataee, Alireza; Darvishi Cheshmeh Soltani, Reza; Rezaee, Reza

2018-07-15

In the present work, ultrasonically facilitated adsorption (UFA) of a cationic dye [Basic Red 46 (BR46)] was examined using cellulosic nanostructures obtained from broom and cooler straw. Although the exclusive application of the nanostructured broom resulted in the 43.51% adsorption of BR46, the UFA process gave rise to the substantial removal efficiency of about 93%. In the case of the nanostructured straw, the efficiency was increased from 36.9% to 55.7%. The UFA process for both adsorbents reached the equilibrium within 60 min which was shorter than the time for the only adsorption. According to the values of the mean free energy (E), the decolorization via the UFA process applying broom (15.81 kJ/mol) and straw (11.18 kJ/mol) nanostructures was occurred chemically. An insignificant loss in the adsorption capacity of both adsorbents was observed after three regeneration tests by means of 0.05 M hydrochloric acid, indicating the good reusability potential of the as-synthesized cellulosic nanostructures. Copyright © 2018 Elsevier Inc. All rights reserved.

A concept of passive safety pressurized water reactor system with inherent matching nature of core heat generation and heat removal

International Nuclear Information System (INIS)

Murao, Yoshio; Araya, Fumimasa; Iwamura, Takamichi; Okumura, Keisuke

1995-01-01

The reduction of manpower in operation and maintenance by simplification of the system are essential to improve the safety and the economy of future light water reactors. At the Japan Atomic Energy Research Institute (JAERI), a concept of a simplified passive safety reactor system JPSR was developed for this purpose and in the concept minimization of developing work and conservation of scale-up capability in design were considered. The inherent matching nature of core heat generation and heat removal rate is introduced by the core with high reactivity coefficient for moderator density and low reactivity coefficient for fuel temperature (Doppler effect) and once-through steam generators (SGs). This nature makes the nuclear steam supply system physically-slave for the steam and energy conversion system by controlling feed water mass flow rate. The nature can be obtained by eliminating chemical shim and adopting in-vessel control rod drive mechanism (CRDM) units and a low power density core. In order to simplify the system, a large pressurizer, canned pumps, passive residual heat removal systems with air coolers as a final heat sink and passive coolant injection system are adopted and the functions of volume and boron concentration control and seal water supply are eliminated from the chemical and volume control system (CVCS). The emergency diesel generators and auxiliary component cooling system of 'safety class' for transferring heat to sea water as a final heat sink in emergency are also eliminated. All of systems are built in the containment except for the air coolers of the passive residual heat removal system. The analysis of the system revealed that the primary coolant expansion in 100% load reduction in 60 s can be mitigated in the pressurizer without actuating the pressure relief valves and the pressure in 50% load change in 30 s does not exceed the maximum allowable pressure in accidental conditions in regardless of pressure regulation. (author)

Method to improve near-field nonlinearity of a high-power diode laser array on a microchannel cooler

Science.gov (United States)

Zhang, Hongyou; Jia, Yangtao; Cai, Wanshao; Tao, Chunhua; Zah, Chung-en; Liu, Xingsheng

2018-03-01

Due to thermal stress, each emitter in a semiconductor laser bar or array is vertically displaced along the p-n junction; the result is that each emitter is not in a line, called near-field nonlinearity. Near-field nonlinearity along a laser bar (also known as "SMILE" effect) degrades the laser beam brightness, which causes an adverse effect on optical coupling and beam shaping. A large SMILE value causes a large divergence angle after collimation and a wider line after collimation and focusing. We simulate the factors affecting the SMILE value of a high-power diode laser array on a microchannel cooler (MCC). According to the simulation results, we have fabricated a series of laser bars bonded on MCCs with lower SMILE value. After simulation and experiment analysis, we found the key factor to affect SMILE is the deformation of the thin MCC because of the distribution of strain and stress in it. We also decreased the SMILE value of 1-cm-wide full bar AuSn bonded on MCCs from 12 to 1 μm by balancing force on MCC to minimize the deformation.

FPGA-based upgrade of the read-out electronics for the low energy polarimeter at the cooler synchrotron

Energy Technology Data Exchange (ETDEWEB)

Hempelmann, Nils [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Collaboration: JEDI-Collaboration

2015-07-01

The Cooler Synchrotron (COSY) is a storage ring used for experiments with polarized proton and deuteron beams. The low energy polarimeter is used to determine the vector and tensor polarization of the beam before injection at kinetic energies up to 45 MeV for protons and 75 MeV for deuterons. The polarimeter uses scintillators to measure the energy of both outgoing particles of a scattering reaction and the time between their detection. The present read-out electronics consists of analog NIM modules and is limited in terms of time resolution and the capability for online data analysis. The read-out electronics will be replaced with a a new system based on analog pulse sampling and an FPGA chip for logic operations. The new system will be able to measure the time at which particles arrive to a precision better than 50 ps, facilitating better background reduction using coincidence measurement. In addition to measuring the beam polarization, the system will be used to precisely determine the vector and tensor analyzing powers for deuteron scattering off carbon at a kinetic energy of 75 MeV.

Effect of cold water and inverse lighting on growth performance of broiler chickens under extreme heat stress.

Science.gov (United States)

Park, Sang-oh; Park, Byung-sung; Hwangbo, Jong

2015-07-01

The present study was carried out to investigate the effect of provision of extreme heat stress diet (EHD), inverse lighting, cold water on growth performance of broiler chickens exposed to extreme heat stress. The chickens were divided into four treatment groups, (T1, T2, T3, T4) as given below: Ti (EHD 1, 10:00-19:00 dark, 19:00-10:00 light, cool water 9 degrees C); T2 (EHD 2, 10:00-19:00 dark, 19:00-10:00 light, cool water 9 degrees C); T3 (EHD 1, 09:00-18:00 dark, 18:00-09:00 light, cool water 141C); T4 (EHD 2, 09:00-18:00 dark, 18:00-09:00 light, cool water 14 degrees C. EHD 1 contained soybean oil, molasses, methionine and lysine; EHD 2 contained the same ingredients as EHD 1 with addition of vitamin C. Groups T1 and T2 were given cooler water than the othertwo groups, and displayed higher body weight increase and diet intake as compared to T3 and T4 (pstress diet, inverse lighting (10:00-19:00 dark, 19:00-10:00 light) with cold water at 9 degrees C under extreme heat stress could enhance growth performance of broiler chickens.

Carbon-14, tritium, stable isotope and chemical measurements on thermal waters from the Tauranga region

International Nuclear Information System (INIS)

Stewart, M.K.; McGill, R.C.; Taylor, C.B.; Whitehead, N.E.; Downes, C.J.

1984-03-01

The chemical compositions of groundwater from the Tauranga region are affected to varying degrees by reducing conditions due to buried organic matter. The levels of some dissolved constituents are also affected by mixing with sea water contained within the rocks and by rock-water interaction. Dissolved gas compositions range from oxygen-bearing to methane-bearing reflecting the varying redox conditions. Excess air may be present but further experiments are necessary to confirm this. Apparent ages deduced from carbon-14 measurements (corrected using 12C dilution and 13C fractionation methods) range from 2-25,000 years, suggesting that some of the waters were recharged during late Pleistocene or early Holocene time. ΔD and Δ18 O values of the oldest waters are slightly more negative than those of younger samples; this may indicate recharge during a cooler climate, in agreement with the 14C ages. Very low but significantly non-zero tritium contents (TR=(0.007-0.059)+-0.007) were measured using the high tritium-enrichment facilities at INS and the very low-background counters at the University of Bern. The tritium is thought to derive from contamination or nuclear reactions in the aquifer rocks rather than from recharge water

Tests of the heat transfer characteristic of air cooler during cooling by natural convection of the Fast Breeder Reactor plants

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

The purpose of this study is to confirm the heat transfer characteristics of the air cooler (AC) of the Fast Breeder Reactor(FBR) which has a function to remove the residual heat of the reactor by heat exchange between sodium and air in natural convection region if electric power would be lost. In order to confirm the characteristics of the AC installed in the FBR plant, the heat transfer test by using the AC which is installed in the sodium test loop owned by Toshiba Corporation has been planned. In this study, the heat transfer characteristic tests were performed by using the AC in sodium test loop, and the CFD analyses were conducted to evaluate the test results and the heat transfer characteristics of the plant scale AC at the condition of natural convection. In addition, the elemental tests to confirm the influence of the heat transfer tube placement by using the heat transfer tube of the same specification as the AC of Monju were performed. (author)

Sensitivity of Sump Water Temperature to Containment Integrity

Energy Technology Data Exchange (ETDEWEB)

Jang, Misuk; Kim, Seoung Rae [Nuclear Engineering Service and Solution, Daejeon (Korea, Republic of)

2014-05-15

This paper is focused on the containment behavior analysis in the above described cases using GOTHIC-IST (generation of thermal-hydraulic information for containments, industry standard toolset). GOTHIC-IST version 7.2a is an integrated, general purpose thermal-hydraulics software package for design, licensing, safety and operating analysis of nuclear power plant containments and other confinement buildings. In this study, we perform the sensitivity the sump water temperature to containment integrity. For 35% RIH break accident with the malfunction of spray system, local air coolers, ECC(emergency core cooling) pump and heat exchanger, the peak pressure at boiler room do not exceed the design pressure 124kPa(g) of the containment and containment integrity is secured. If accompanied the malfunction of heat exchanger or pump in the time of low pressure safety injection, of ECCS, it will be one of the aggravating factors to the integrity of core and containment.

Analysis of closed orbit deviations for a first direct deuteron electric dipole moment measurement at the cooler synchrotron COSY

Science.gov (United States)

Schmidt, V.; Lehrach, A.

2017-07-01

The Jülich Electric Dipole moment Investigations (JEDI) collaboration in Julich is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. Ensuring a precise measurement, various beam and spin manipulating effects have to be considered and investigated. A distortion of the closed orbit is one of the major sources for systematic uncertainties. Therefore misalignments of magnets and residual power supply oscillations are simulated using the MAD-X code in order to analyse their effect on the orbit. The underlying model for all simulations includes the dipoles, quadrupoles and sextupoles at COSY as well as the corrector magnets and BPMs (Beam Position Monitors). Since most sextupoles are only used during beam extraction, the sextupole strengths are set to zero resulting in a linear machine. The optics is adjusted in a way that the dispersion is zero in the straight sections. The closed orbit studies are performed for deuterons with a momentum of 970 MeV/c.

Processing of coke oven gas. Primary gas cooling

Energy Technology Data Exchange (ETDEWEB)

Ullrich, H [Otto (C.) und Co. G.m.b.H., Bochum (Germany, F.R.)

1976-11-01

The primary cooler is an indispensable part of all byproduct processing plants. Its purpose is to cool the raw gas from the coke oven battery and to remove the accompanying water vapor. The greater part of the cooling capacity is utilized for the condensation of water vapor and only a small capacity is needed for the gas cooling. Impurities in the gas, like naphthalene, tar and solid particles, necessitate a special design in view of the inclination to dirt accumulation. Standard types of direct and indirect primary gas coolers are described, with a discussion of their advantages and disadvantages.

Comparative study in LTC Combustion between a short HP EGR loop without cooler and a variable lift and duration system

Energy Technology Data Exchange (ETDEWEB)

Bression, Guillaume; Pacaud, Pierre; Soleri, Dominique; Cessou, Jerome [IFP (France); Azoulay, David [Renault Powertrain Div. (France); Lawrence, David [Mechadyne (United Kingdom); Doradoux, Laurent; Guerrassi, Noureddine [Delphi Diesel Systems (France)

2008-07-01

In order to reach future Diesel emission standards such as Euro 6 or Tier 2 Bin 5, NO{sub x} emissions need to be dramatically reduced. Advanced technologies and engine settings such as higher EGR rates, reduced compression ratio, EGR cooler and low-pressure EGR loop - depending on vehicle application - may help to reach this target whilst maintaining low CO{sub 2} emissions and fuel consumption. However, the resulting low combustion temperatures and the low air-fuel ratios lead to a significant increase in HC and CO emissions, especially during the start-up phase prior to catalyst light-off. Moreover, high levels of EGR make transient operation even more difficult. So HC-CO emissions and EGR transient operation represent two key issues that could limit the extension of this alternative combustion mode. Consequently, an in-depth investigation of a variable lift and duration (VLD) system was performed to overcome these problems on a 4-cylinder engine, which was also equipped with a dual HP-LP EGR loop. The VLD system tested in this paper produces a variable camshaft-operated exhaust valve re-opening, which is controlled by a hydraulic rotary actuator, ensuring quick and accurate regulation of the internal gas recirculation (IGR). By increasing gas temperature in the combustion chamber, this advanced technology allows us to reduce HC-CO emissions by 50% under 3 bar BMEP. Although efficient, this technology has to be compared with other solutions from a cost-to-value point of view. The aim of this paper is firstly to compare the double lift exhaust system with a short route high-performance EGR loop without cooler by quantifying their respective gains on steady state points of the NEDC cycle, then by evaluating their potential performances during transient conditions. With the short-route EGR, the potential in HC-CO emission reduction remains significant on a large scale of engine temperatures representative of engine warm up. However, the VLD system allows us to

Heat capacity mapping mission (HCMM) thermal surface water mapping and its correlation to LANDSAT

International Nuclear Information System (INIS)

Colvocoresses, A.P.

1980-03-01

Graphics are presented which show HCMM mapped water-surface temperature in Lake Anna, a 13,000 dendrically-shaped lake which provides cooling for a nuclear power plant in Virginia. The HCMM digital data, produced by NASA were processed by NOAA/NESS into image and line-printer form. A LANDSAT image of the lake illustrates the relationship between MSS band 7 data and the HCMM data as processed by the NASA image processing facility which transforms the data to the same distortion-free hotline oblique Mercator projection. Spatial correlation of the two images is relatively simple by either digital or analog means and the HCMM image has a potential accuracy approaching the 80 m of the original LANDSAT data. While it is difficult to get readings that are not diluted by radiation from cooler adjacent land areas in narrow portions of the lake, digital data indicated by the line-printer display five different temperatures for open-water areas. Where the water surface response was not diluted by land areas, the temperature difference recorded by HCMM corresponds to in situ readings with rsme on the order of 1 C

77 FR 277 - Sabine Pass Liquefaction, LLC and Sabine Pass LNG, L.P; Notice of Availability of the...

Science.gov (United States)

2012-01-04

... contains gas treatment facilities, six gas turbine-driven refrigerant compressors, waste heat recovery systems, induced draft air coolers, fire and gas detection and safety systems, control systems, and... compressors, potable water, service water, and demineralized water systems); and New and remodeled buildings...

A thermodynamic analysis of a transcritical cycle with refrigerant mixture R32/R290 for a small heat pump water heater

Energy Technology Data Exchange (ETDEWEB)

Yu, Jianlin; Xu, Zong; Tian, Gaolei [Department of Refrigeration and Cryogenic Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, West Xianning Road, No. 28, Xianning West Road, Xi' an Shaanxi 710049 (China)

2010-12-15

In this study, a thermodynamic analysis on the performance of a transcritical cycle using azeotropic refrigerant mixtures of R32/R290 with mass fraction of 70/30 has been performed. The main purpose of this study is to theoretically verify the possibility of applying the chosen refrigerant mixture in small heat pumps for high temperature water heating applications. Performance evaluation has been carried out for a simple azeotropic mixture R32/R290 transcritical cycle by varying evaporator temperature, outlet temperature of gas cooler and compressor discharge pressure. Furthermore, the effects of an internal heat exchanger on the transcritical R32/R290 cycle have been presented at different operating conditions. The results show that high heating coefficient of performance (COP{sub h}) and volumetric heating capacity can be achieved by using this transcritical cycle. It is desirable to apply the chosen refrigerant mixture R32/R290 in small heat pump water heater for high temperature water heating applications, which may produce hot water with temperature up to 90 C. (author)

Timing of Indonesian Gateway Restriction Between 4.0 and 2.8 Ma and its Impact on Indian Ocean Surface Waters Based on Calcareous Nannoplankton Assemblages

Science.gov (United States)

Auer, G.; De Vleeschouwer, D.; Groeneveld, J.; Bogus, K.; Henderiks, J.; Castañeda, I. S.; Expedition 356 Scientists, I.

2017-12-01

The Early Pliocene is characterized by a fundamental reorganization of Earth's climate. In particular, the ongoing constriction of the Indonesian Gateway (IG) around 4.0 - 3.0 Ma is commonly evoked cause for these climatic changes (Christensen et al., 2017; De Schepper et al., 2014; Karas et al., 2009; 2017). The constriction of the IG, caused by the northward movement of Australia and related uplift of Indonesia, had major effects on global climate and may have contributed to Northern Hemisphere cooling via complex atmospheric and oceanographic teleconnections. Untangling the exact timing of IG constriction is thus critical for resolving the mechanisms driving Earth's climatic evolution during the Pliocene. Here we present high-resolution reconstructions of surface water conditions and IG connectivity using calcareous nannoplankton (CNP) assemblages between 4.0 and 2.8 Ma at Site U1463 (18°59'S, 117°37'E; IODP Expedition 356). Located on the Northwest Shelf (NWS) of Australia, the site lies directly in the path of the upper branch of the Leeuwin-Holloway current, making it an ideal location to study Pliocene IG dynamics and their influence on the eastern Indian Ocean. Using modern analogue based interpretation of CNP assemblages, in combination with an independent orbitally tuned age model, shows a change in surface water conditions along the NWS 3.8 Ma recognizable by a decrease in tropical taxa like Umbilicosphaera sibogae and Sphenolithus spp. Subsequently, a shift from Gephyrocapsa sp. to Reticulofenestra sp. dominated CNP assemblages and the increase of mesotrophic CNP taxa (e.g. Umbilicosphaera jafari; Helicosphaera spp.), suggests that warm, stratified, oligotrophic (i.e. tropical) waters were replaced by cooler, more turbulent, and less saline waters by 3.8 - 3.6 Ma. We relate this switch in dominant water masses to changes in IG geometry delivering relatively cooler and fresher waters from northern Pacific sources to the NWS. The abundance of

Vacuum packaging of InGaAs focal plane array with four-stage thermoelectric cooler

Science.gov (United States)

Mo, De-feng; Liu, Da-fu; Yang, Li-yi; Xu, Qin-fei; Li, Xue

2013-09-01

The InGaAs focal plane array (FPA) detectors, covering the near-infrared 1~2.4 μm wavelength range, have been developed for application in space-based spectroscopy of the Earth atmosphere. This paper shows an all-metal vacuum package design for area array InGaAs detector of 1024×64 pixels, and its architecture will be given. Four-stage thermoelectric cooler (TEC) is used to cool down the FPA chip. To acquire high heat dissipation for TEC's Joule-heat, tungsten copper (CuW80) and kovar (4J29) is used as motherboard and cavity material respectively which joined by brazing. The heat loss including conduction, convection and radiation is analyzed. Finite element model is established to analyze the temperature uniformity of the chip substrate which is made of aluminum nitride (AlN). The performance of The TEC with and without heat load in vacuum condition is tested. The results show that the heat load has little influence to current-voltage relationship of TEC. The temperature difference (ΔT) increases as the input current increases. A linear relationship exists between heat load and ΔT of the TEC. Theoretical analysis and calculation show that the heat loss of radiation and conduction is about 187 mW and 82 mW respectively. Considering the Joule-heat of readout circuit and the heat loss of radiation and conduction, the FPA for a 220 K operation at room temperature can be achieved. As the thickness of AlN chip substrate is thicker than 1 millimeter, the temperature difference can be less than 0.3 K.

The Influence of Heat Treatment and Quencing Media at Bronze 80% Cu–20% Sn toward Fatique Life

Directory of Open Access Journals (Sweden)

Anak Agung Istri Agung Sri Komaladewi

2012-11-01

Full Text Available Production of the Balinese gamelan product rest on molding process which then continued with forging process, adjustment,and finally the finishing process. But still often to make the failure from this material like. The material become brokebecause heavy thing with the user processing (playing gambelan with continuity in the long time. The broke that happenfrom the heavy thing by the continuety that is called fatigue. At this examination the things that will be up is how much theheat treatment influence and the cooler thing with the fatigue life through the Reversed Bending process. By to variated theheat treatment and cooler thing to Bronze mixture 80%Cu and 20%Sn. This examination to aim at knowing the heattreatment influence and cooler thing at the composition of Bronze 80%Cu and 20%Sn about the fatigue life.The makingprocess of this things made by copper solution and the white Tin with the composition are 80%Cu and 20%Sn by variatedheat treatment and cooler media. The produce of this solution will print with the Reversed Bending speciment. Then thespeciment gift the heat treatment about 6500 C, 7000 C till 7500 C, and then the speciment keep cold by the water, oil and theair. The thing will be analize from the breach counture, Macro Structure and Micro Structure.The examination produceshowing the growing up at the fatigue life in the Bronze mixture 80%Cu - 20%Sn, From the heat treatment 6500 C, 7000 Cand 7500 C and become the drop age fatigue with the water cooler media with the age fatigue abaut 36621 cycle, and thefatigue by oil about 44975 cycle and the air cooler age fatigue about 55191 cycle. The inspection makro structure thebreach face colouring litle bit dark and the inspection mikro structure, the metal structure lool more bright.

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

International Nuclear Information System (INIS)

Farforovsky, V.B.

1990-01-01

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

Shell coal IGCCS with carbon capture. Conventional gas quench vs. innovative configurations

Energy Technology Data Exchange (ETDEWEB)

Martellia, E.; Consonni, S. [Politecnico di Milano, Via Scalabrini 76, Piacenza (Italy); Kreutz, T. [Princeton University, Guyot Hall, Room 129, Princeton, NJ (United States); Carbo, M.; Jansen, D. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG, Petten (Netherlands)

2011-11-15

The Shell coal integrated gasification combined cycle (IGCC) based on the gas quench system is one of the most fuel flexible and energy efficient gasification processes because is dry feed and employs high temperature syngas coolers capable of rising high pressure steam. Indeed the efficiency of a Shell IGCC with the best available technologies is calculated to be 47-48%. However the system looses many percentage points of efficiency (up to 10) when introducing carbon capture. To overcome this penalty, two approaches have been proposed. In the first, the expensive syngas coolers are replaced by a 'partial water quench' where the raw syngas stream is cooled and humidified via direct injection of hot water. This design is less costly, but also less efficient. The second approach retains syngas coolers but instead employs novel water-gas shift (WGS) configurations that requires substantially less steam to obtain the same degree of CO conversion to CO2, and thus increases the overall plant efficiency. We simulate and optimize these novel configurations, provide a detailed thermodynamic and economic analysis and investigate how these innovations alter the plant's efficiency, cost and complexity.

Water-Stressed Loquat Trees Need More Time and Heat to Ripen Their Fruits

Directory of Open Access Journals (Sweden)

Julián Cuevas

2018-06-01

Full Text Available To determine if water-stressed trees need more time and heat to mature their fruits, we compared chronological and thermal time from bloom to harvest among control fully-irrigated ‘Algerie’ loquat trees and trees suffering prior-to-bloom deficit irrigation (DI. Heat requirement calculation was performed using the double sine method with a lower threshold temperature of 3 °C. The results show that the greater the blooming advancement achieved by DI, the longer the period to mature the fruits. Such a pattern indicates that the longer duration for bloom-harvest period under DI is due to a displacement of the reproductive phenology to cooler dates. However, some effects of DI on heat requirements for ripening persist, indicating a slower fruit development in some, but not all, DI treatments. The differences in fruit development rate between fully-irrigated and water-stressed trees were established during the phase of rapid fruit growth. The comparison of water stress effects on sink (flower size and seed number and source (leaf number and size, gas exchange and mineral and carbohydrate nutrition of DI treatments seems to indicate that the amount of stored reserves in the leaves to sustain early fruit development is the most plausible reason behind the increase in thermal time between bloom and harvest in water-stressed loquats.

MODELLING OF RADIONUCLIDE MIGRATION IN THE SYSTEM OF NUCLEAR POWER PLANT BIOLOGICAL PONDS

Directory of Open Access Journals (Sweden)

Ю. Кутлахмедов

2011-04-01

Full Text Available Migration of radionuclide coming from nuclear power plant into the system of biological pondsand then into the water reservoir-cooler is considered in the article. The theme of the work ismodeling of radionuclide migration process in the system of biological ponds on the example of thePivdennoukrainska nuclear power plant using chamber models method. Typical water ecosystemconsisting of three chambers (chamber-water, chamber-biota and chamber-bed silt was the basistaken by the authors. Application of chamber models method allowed authors to develop thedynamic chamber model of radionuclide migration in nuclear power plant biological ponds. Thismodel allows to forecast values and dynamics of radioactive water pollution based on limitedecosystem monitoring data. Thus, parameters of radioactive capacity of nuclear power plantbiological ponds system and water reservoir-cooler were modeled by authors, the estimation andprognosis of radionuclide distribution and accumulation in the system of nuclear power plantbiological ponds were done. Authors also explain the roles of basin water, biomass and bed silt inradionuclide deposition

The Behavior of Corrosion Products in Sampling Systems under Boiling Water Reactor Conditions

Energy Technology Data Exchange (ETDEWEB)

Hermansson, Hans-Peter

1977-08-15

A high pressure loop has been used to simulate sampling systems employed under BWR conditions. The reliability of the sampling method was studied in a series of six test runs. A variety of parameters that are thought to influence the reliability of the sampling was investigated. These included piping geometry, water oxygen content, flow, temperature and temperature gradients. Amongst other things the results indicate that the loss by deposition of iron containing corrosion products does not exceed 50 %; this figure is only influenced to a minor extent by the above mentioned parameters. The major part of the corrosion products thus deposited is found along the first few meters of the piping and cooler coil. A moderate prolongation of a pipe which is already relatively long should thus be incapable of producing a major influence on the sampling error

77 FR 72763 - Energy Conservation Program: Certification of Commercial and Industrial HVAC, Refrigeration and...

Science.gov (United States)

2012-12-06

... Commercial and Industrial HVAC, Refrigeration and Water Heating Equipment AGENCY: Office of Energy Efficiency...; commercial heating, ventilating, air-conditioning (HVAC) equipment; and commercial water heating equipment... refrigeration equipment; commercial HVAC equipment; commercial WH equipment; and walk-in coolers and freezers...

Longitudinal thermal heterogeneity in rivers and refugia for coldwater species: effects of scale and climate change

Science.gov (United States)

Climate-change driven increases in water temperature pose multiple challenges for aquatic organisms. Predictions of climate change impacts to biota typically do not account for fine-grained spatiotemporal patterns of stream networks; yet patches of cooler water within rivers c...

Theoretical analysis of thermal molten metal-water reactions

International Nuclear Information System (INIS)

Schwalbe, W.

1982-01-01

In experiments with greater masses (kg-scale) two extreme cases had been oberved during the course of reaction when hot melt reacted with a vaporizable cooler liquid. Relatively mild hot interactions with slow pressure build-up and small pressure peak in the reaction volume often occurred but there were also some very violent reactions (steam explosions) where a remarkable portion of thermal energy had been transformed into mechanical energy with high pressure peaks. For the two types of reactions overall models for water as a coolant are developed here. Based on calculations and on comparisons with corresponding experiments it is shown that a relatively mild course of reaction can be explained by a fragmentation of the melt under following violent evaporation of the cooling medium. Pressures only with small reaction volumes up to the MPa range can be found in these reactions. The calculations, for example of Bird and Millington, showed a pressure maximum of 1 MPa after 170 ms of the start of the reaction; this agrees very well with the result of the experiment of 1.08 MPa. (orig./GL) [de

Cooling of nuclear power stations with high temperature reactors and helium turbine cycles

International Nuclear Information System (INIS)

Foerster, S.; Hewing, G.

1977-01-01

On nuclear power stations with high temperature reactors and helium turbine cycles (HTR-single circuits) the residual heat from the energy conversion process in the primary and intermediate coolers is removed from cycled gas, helium. Water, which is circulated for safety reasons through a closed circuit, is used for cooling. The primary and intermediate coolers as well as other cooling equipment of the power plant are installed within the reactor building. The heat from the helium turbine cycle is removed to the environment most effectively by natural draught cooling towers. In this way a net plant efficiency of about 40% is attainable. The low quantities of residual heat thereby produced and the high (in comparison with power stations with steam turbine cycles) cooling agent pressure and cooling water reheat pressure in the circulating coolers enable an economically favourable design of the overall 'cold end' to be expected. In the so-called unit range it is possible to make do with one or two cooling towers. Known techniques and existing operating experience can be used for these dry cooling towers. After-heat removal reactor shutdown is effected by a separate, redundant cooling system with forced air dry coolers. The heat from the cooling process at such locations in the power station is removed to the environment either by a forced air dry cooling installation or by a wet cooling system. (orig.) [de

Energetic optimization of the chilled water systems operation at hotels

Directory of Open Access Journals (Sweden)

Reineris Montero Laurencio

2015-12-01

Full Text Available The hotel exploitation, while continuing to satisfy the customers, needs to decrease the requests of electric power as the principal energy carrier. Solving issues regarding the occupation of a hotel integrally, taking the air conditioning as center of attention, which demands the bigger consumptions of electricity, results in a complex task. To solve this issue, a procedure was implemented to optimize the operation of the water-chilled systems. The procedure integrates an energy model with a strategy of low occupation following energetic criteria based on combinatorial-evolutionary criteria. To classify the information, the formulation of the tasks and the synthesis of the solutions, a methodology of analysis and synthesis of engineering is used. The energetic model considers the variability of the local climatology and the occupation of the selected rooms, and includes: the thermal model of the building obtained by means of artificial neural networks, the hydraulic model and the model of the compression work. These elements allow to find the variable of decision occupation, performing intermediate calculations to obtain the velocity of rotation in the centrifugal pump and the output temperature of the cooler water, minimizing the requirements of electric power in the water-chilled systems. To evaluate the states of the system, a combinatorial optimization is used through the following methods: simple exhaustive, stepped exhaustive or genetic algorithm depending on the quantity of variants of occupation. All calculation tasks and algorithms of the procedure were automated through a computer application.

Emergency cooling system for a liquid metal cooled reactor

International Nuclear Information System (INIS)

Murata, Ryoichi; Fujiwara, Toshikatsu.

1980-01-01

Purpose: To suitably cool liquid metal as coolant in emergency in a liquid metal cooled reactor by providing a detector for the pressure loss of the liquid metal passing through a cooling device in a loop in which the liquid metal is flowed and communicating the detector with a coolant flow regulator. Constitution: A nuclear reactor is stopped in nuclear reaction by control element or the like in emergency. If decay heat is continuously generated for a while and secondary coolant is insufficiently cooled with water or steam flowed through a steam and water loop, a cooler is started. That is, low temperature air is supplied by a blower through an inlet damper to the cooler to cool the secondary coolant flowed into the cooler through a bypass pipe so as to finally safely stop an entire plant. Since the liquid metal is altered in its physical properties by the temperature at this time, it is detected to regulate the opening of the valve of the damper according to the detected value. (Sekiya, K.)

Use of the water supply system of special purpose in buildings

Directory of Open Access Journals (Sweden)

Orlov Evgeniy Vladimirovich

proved upon transition from coolers on machine guns of drinking water that allowed refusing the order of plastic bottles, which after use start accumulating on dumps, polluting the environment.

δD values of hydrated volcanic glass : a potential record of ancient meteoric water and climate in New Zealand

International Nuclear Information System (INIS)

Shane, P.; Ingraham, N.

2002-01-01

Tephra beds that are well drained and have been buried by thin paleosols become hydrated within 2-3000 yr on reaction with meteoric waters. Hence, the absorbed water within silicic volcanic glass shards provides a potential record of δD values of ancient meteoric water. Such isotopic records have previously received little investigation. We demonstrate that 1.5-2 m thick tephra beds in central North Island, New Zealand, display uniform δD values vertically through their profiles and laterally up to 250 m in outcrop. Reproducibility is not influenced by grain size or age of the tephra. We obtained an average δD value of -48 ± 3 permille for water within the 1.8 ka Taupo Tephra. This is similar to the composition of present-day surface waters. δD values of -73 ± 2 and -60 ± 2 permille for the 25 ka Kawakawa and 30 ka Mangaone Tephra beds are significantly lower than present waters, indicating that they have been hydrated under different surficial conditions. This is consistent with other proxy paleoclimatic indicators that suggest a cooler, drier, and windier climate at the time of their eruption. Tephra beds are a potential source of paleoclimatic data in terrestrial environments that otherwise may lack proxy records. (author). 17 refs., 5 figs., 3 tabs

Containment fan cooler heat transfer calculation during main steam line break for Maanshan PWR plant

Energy Technology Data Exchange (ETDEWEB)

Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw; Kao, Lain-Su, E-mail: lskao@iner.gov.tw

2013-10-15

Highlights: • Evaluate component cooling water (CCW) thermal response during MSLB for Maanshan. • Using GOTHIC to calculate CCW temperature and determine time required to boil CCW. • Both convective and condensation heat transfer from the air side are considered. • Boiling will not occur since T{sub B} is sufficiently longer than CCW pump restart time. -- Abstract: A thermal analysis has been performed for the Containment Fan Cooler Unit (FCU) during Main Steam Line Break (MSLB) accident, concurrent with loss of offsite power, for Maanshan PWR plant. The analysis is performed in order to address the waterhammer and two-phase flow issues discussed in USNRC's Generic Letter 96-06 (GL 96-06). Maanshan plant is a twin-unit Westinghouse 3-loop PWR currently operated at rated core thermal power of 2822 MWt for each unit. The design basis for containment temperature is Main Steam Line Break (MSLB) accident at power of 2830.5 MWt, which results in peak vapor temperature of 387.6 °F. The design is such that when MSLB occurs concurrent with loss of offsite power (MSLB/LOOP), both the coolant pump on the secondary side and the fan on the air side of the FCU loose power and coast down. The pump has little inertia and coasts down in 2–3 s, while the FCU fan coasts down over much longer period. Before the pump is restored through emergency diesel generator, there is potential for boiling the coolant in the cooling coils by the high-temperature air/steam mixture entering the FCU. The time to boiling depends on the operating pressure of the coolant before the pump is restored. The prediction of the time to boiling is important because it determines whether there is potential for waterhammer or two-phase flow to occur before the pump is restored. If boiling occurs then there exists steam region in the pipe, which may cause the so called condensation induced waterhammer or column closure waterhammer. In either case, a great amount of effort has to be spent to

Thermal Water of Utah Topical Report

Energy Technology Data Exchange (ETDEWEB)

Goode, Harry D.

1978-11-01

Western and central Utah has 16 areas whose wells or springs yield hot water (35 C or higher), warm water (20-34.5 C), and slightly warm water (15.5-19.5 C). These areas and the highest recorded water temperature for each are: Lower Bear River Area, 105 C; Bonneville Salt Flats, 88 C; Cove Fort-Sulphurdale, 77 C; Curlew Valley, 43 C; East Shore Area, 60 C; Escalante Desert, 149 C; Escalante Valley (Roosevelt, 269 C, and Thermo, 85C); Fish Springs, 60.5 C; Grouse Creek Valley, 42 C; Heber Valley (Midway, 45 C); Jordan Valley, 58.5 C; Pavant Valley-Black Rock Desert, 67 C; Sevier Desert ( Abraham-Crater Hot Springs, 82 C); Sevier Valley (Monroe-Red Hill, 76.5 C, and Joseph Hot Spring, 64 C); Utah Valley, 46 C; and Central Virgin River Basin, 42 C. The only hot water in eastern Utah comes from the oil wells of the Ashley Valley Oil Field, which in 1977 yielded 4400 acre-feet of water at 43 C to 55 C. Many other areas yield warm water (20 to 34.5 C) and slightly warm water (15.5 to 19.5 C). With the possible exception of the Roosevelt KGRA, Crater Hot Springs in the Sevier Desert, Escalante Desert, Pavant-Black Rock, Cove Fort-Sulphurdale, and Coyote Spring in Curlew Valley, which may derive their heat from buried igneous bodies, the heat that warms the thermal water is derived from the geothermal gradient. Meteoric water circulates through fractures or permeable rocks deep within the earth, where it is warmed; it then rises by convection or artesian pressure and issues at the surface as springs or is tapped by wells. Most thermal springs thus rise along faults, but some thermal water is trapped in confined aquifers so that it spreads laterally as it mixes with and warms cooler near-surface water. This spreading of thermal waters is evident in Cache Valley, in Jordan Valley, and in southern Utah Valley; likely the spreading occurs in many other artesian basins where it has not yet been recognized. In the East Shore Area thermal water trapped in confined aquifers warms

Geochemical and Mineralogical Changes in Compacted MX-80 Bentonite Submitted to Heat and Water Gradients

International Nuclear Information System (INIS)

Gomez-Espina, R.; Villar, M. V.

2010-01-01

A 20-cm high column of MX80 bentonite compacted at dry density 1.70 g/cm 3 with an initial water content of 16 percent was submitted to heating and hydration by opposite ends for 496 days (TH test). The temperature at the bottom of the column was set at 140 degree centigrade and on top at 30 degree centigrade, and deionised water was injected on top at a pressure of 0.01 MPa. Upon dismantling water content, dry density, mineralogy, specific surface area, cation exchange capacity, content of exchangeable cations, and concentration of soluble salts and pH of aqueous extracts were determined in different positions along the bentonite column. The pore water composition was modelled with a geochemical software. The test tried to simulate the conditions of an engineered barrier in a deep geological repository for high-level radioactive waste. The water intake and distribution of water content and dry density along the bentonite were conditioned by the thermal gradient. Liquid water did not penetrate into the column beyond the area in which the temperature was higher than 100 degree centigrade. A convection cell was formed above this area, and liquid water loaded with ions evaporated towards cooler bentonite as it reached the area where the temperature was too high. In this area precipitation of mineral phases took place, Advection, interlayer exchange and dissolution/precipitation processes conditioned the composition of the pore water along the column. In most of the column the pore water was Na-SO 4 2 - type, and changed to Na-Cl near the heater. TH treatment did not cause significant changes in the smectite content or the other mineral phases of the bentonite. (Author) 41 refs.

Geochemical and Mineralogical Changes in Compacted MX-80 Bentonite Submitted to Heat and Water Gradients

Energy Technology Data Exchange (ETDEWEB)

Gomez-Espina, R.; Villar, M. V.

2010-05-01

A 20-cm high column of MX80 bentonite compacted at dry density 1.70 g/cm{sup 3} with an initial water content of 16 percent was submitted to heating and hydration by opposite ends for 496 days (TH test). The temperature at the bottom of the column was set at 140 degree centigrade and on top at 30 degree centigrade, and deionised water was injected on top at a pressure of 0.01 MPa. Upon dismantling water content, dry density, mineralogy, specific surface area, cation exchange capacity, content of exchangeable cations, and concentration of soluble salts and pH of aqueous extracts were determined in different positions along the bentonite column. The pore water composition was modelled with a geochemical software. The test tried to simulate the conditions of an engineered barrier in a deep geological repository for high-level radioactive waste. The water intake and distribution of water content and dry density along the bentonite were conditioned by the thermal gradient. Liquid water did not penetrate into the column beyond the area in which the temperature was higher than 100 degree centigrade. A convection cell was formed above this area, and liquid water loaded with ions evaporated towards cooler bentonite as it reached the area where the temperature was too high. In this area precipitation of mineral phases took place, Advection, interlayer exchange and dissolution/precipitation processes conditioned the composition of the pore water along the column. In most of the column the pore water was Na-SO{sub 4} {sup 2}- type, and changed to Na-Cl near the heater. TH treatment did not cause significant changes in the smectite content or the other mineral phases of the bentonite. (Author) 41 refs.

Pressure tube reactors

International Nuclear Information System (INIS)

Natori, Hisahide.

1981-01-01

Purpose: To improve the electrical power generation efficiency in a pressure tube reactor in which coolants and moderators are separated by feedwater heating with heat generated in heavy water and by decreasing the amount of steams to be extracted from the turbine. Constitution: A heat exchanger and a heavy water cooler are additionally provided to a conventional pressure tube reactor. The heat exchanger is disposed at the pre-stage of a low pressure feedwater heater series. High temperature heavy water heated in the core is passed through the primary side of the exchanger, while feedwater is passed through the secondary side. The cooler is disposed on the downstream of the heat exchanger in the flowing direction of the heavy water, in which heavy water from the heat exchanger is passed through the primary side and the auxiliary equipment cooling water is sent to the secondary side thereof. Accordingly, since extraction of heating steams is no more necessary, the steam can be used for the rotation of the turbine, and the electrical power generation efficiency can be improved. (Seki, T.)

Ten steps to a cooler planet

International Nuclear Information System (INIS)

2001-01-01

The overwhelming scientific consensus is that human activities, especially activities that produce greenhouse gases are accumulating in the atmosphere and are changing the intricate balance that has sustained life on earth for millions of years. The estimate is that in Canada about 35 per cent of the greenhouse gases released to the atmosphere come from personal sources. This booklet provides brief account of the ways that individuals contribute to green house gas emissions and provides some helpful hints on how to reduce this personal contribution to the climate change problem. The ten ways suggested are: (1) use public transport as much as possible, (2) buy smaller cars , (3) use the train instead of flying, make fewer long distance trips by combining business and vacation travel, (4) set the thermostat one degree lower and save 525 kg of carbon dioxide per year, (5) avoid overhousing by choosing a smaller house and by making every square foot count, (6) buy energy efficient appliances, (7) reduce water heater's energy consumption by insulating it, (8) reduce meat intake and buy locally produced food in season, (9) minimize garbage production by reusing and recycling, (10) use green power wherever available and contribute to the development of renewable energy sources

Climate change and managing water crisis: Pakistan's perspective.

Science.gov (United States)

Hussain, Mumtaz; Mumtaz, Saniea

2014-01-01

Climate change is a global phenomenon manifested mainly through global warming. The International Panel on Climate Change (IPCC) has reported its negative consequences on natural resources, anthropogenic activities, and natural disasters. The El Nino and La Nina have affected hydrologic regimes and ecosystems. It has been observed that the average temperature in 1995 was 0.4°C higher than that in 1895. By the end of the 21st century, 10% of the area of Bangladesh is likely to be submerged by the sea. Most of the islands of Pacific Ocean will disappear. A major part of Maldives will be submerged. The sea level is expected to rise by 30-150 cm. Extreme events such as floods, cyclones, tsunamis, and droughts have become regular phenomena in many parts of the world. Other adverse impacts are proliferation of water-borne diseases, sea water intrusion, salinization of coastal areas, loss of biodiversity, eco-degradation of watersheds and global glacial decline, and haphazard snow melts/thaws. In turn, these factors have serious effect on water resources. Pakistan is confronting similar climate change. Meteorological data reveal that winter temperatures are rising and summers are getting cooler. Temperature is expected to increase by 0.9°C and 1.5°C by years 2020 and 2050, respectively. Water resources in Pakistan are affected by climate change as it impacts the behavior of glaciers, rainfall patterns, greenhouse gas emissions, recurrence of extreme events such as floods and droughts. Severe floods have occurred in the years 1950, 1956, 1957, 1973, 1976, 1978, 1988, 1992, 2010, 2011, and 2012. Pakistan has faced the worst-ever droughts during the period from 1998 to 2004. Pakistan has surface water potential of 140 million acre feet (MAF) and underground water reserve of 56 MAF. It is one of the most water-stressed countries in the world. The per capita annual availability of water has reduced from 5140 m3 in 1950 to 1000 m3 now. It is fast approaching towards water

Second law analysis of double effect vapour absorption cooler system

International Nuclear Information System (INIS)

Gomri, Rabah; Hakimi, Riad

2008-01-01

In this paper, exergy analysis of double effect lithium bromide/water absorption refrigeration system is presented. The system consists of a second effect generator between the generator and condenser of the single effect absorption refrigeration system, including two solution heat exchangers between the absorber and the two generators. In order to simulate the refrigeration system by using a computer, a new set of computationally efficient formulations of thermodynamic properties of lithium bromide/water solution developed is used. The exergy analysis is carried out for each component of the system. All exergy losses that exist in double effect lithium bromide/water absorption system are calculated. In addition to the coefficient of performance and the exergetic efficiency of the system, the number of exergy of each component of the system is also estimated. This study suggests the component of the absorption refrigeration system that should be developed. The results show that the performance of the system increases with increasing low pressure generator (LPG) temperature, but decreases with increasing high pressure generator (HPG) temperature. The highest exergy loss occurs in the absorber and in the HPG, which therefore makes the absorber and HPG the most important components of the double effect refrigeration system

The climatic water balance in an ecological context

Science.gov (United States)

Stephenson, N. L.

2011-12-01

; for example, a warmer, wetter environment will support a fundamentally different biota than the original cooler, drier environment. Thus, a sharp distinction must always be made between the effects of changing energy and water supplies, and the terms "wetter" and "drier" must be carefully defined in terms of AET and Deficit. An understanding of the relationships between the water balance and biotic patterns and processes in space -- particularly within the extreme topographic and edaphic complexity of mountain ranges -- provides a solid foundation for understanding and predicting the ecological effects of climatic changes in time. I will provide concrete examples, particularly from California's Sierra Nevada, with emphasis on cases in which predictions may deviate from intuitive expectations.

Gamma-ray application to the measurement of a media distribution at the catalyst cooler of a residue fluid catalytic cracking unit (RFCCU) in the petrochemical industry

International Nuclear Information System (INIS)

Kim, Jin Seop; Jung, Sung Hee; Kim, Jong Bum

2006-01-01

The dynamic behavior of the process media in the petrochemical industry can hardly be observed during its operation. Because the information on the process media is directly related to the processes efficiency, therefore it is necessary to establish what is actually happening inside the process unit. For this purpose, a field experiment was performed to study the fluidized catalyst patterns and confirm the internal conditions by using a sealed gamma-ray source. From the results, the areas showing a different pattern from the surrounding vicinity were found successfully. Especially at the upper part of the connection point at which the pipeline from are generator was joined, a relatively low amount of catalyst was distributed. Sealed gamma-ray application to the catalyst cooler is considered as a worthwhile technique for a measurement of the catalyst distribution at the RFCCU.

Gamma-ray application to the measurement of a media distribution at the catayst cooler of a residue fluid catalytic cracking unit (RFCCU) in the petrochemical industry

International Nuclear Information System (INIS)

Kim, Jin Seop; Jung, Sung Hee; Kim, Jong Bum

2006-01-01

The dynamic behavior of the process media in the petrochemical industry can hardly be observed during its operation. Because the information on the process media is directly related to the processes efficiency, therefore it is necessary to establish what is actually happening inside the process unit. For this purpose, a field experiment was performed to study the fluidized catalyst patterns and confirm the internal conditions by using a sealed gamma-ray source. From the results, the areas showing a different pattern from the surrounding vicinity were found successfully. Especially at the upper part of the connection point at which the pipeline from are generator was joined, a relatively low amount of catalyst was distributed. Sealed gamma-ray application to the catalyst cooler is considered as a worthwhile technique for a measurement of the catalyst distribution at the RFCCU.

Application of cascading thermoelectric generator and cooler for waste heat recovery from solid oxide fuel cells

International Nuclear Information System (INIS)

Zhang, Houcheng; Kong, Wei; Dong, Feifei; Xu, Haoran; Chen, Bin; Ni, Meng

2017-01-01

Highlights: • Cascading thermoelectric devices are proposed to recover waste heat from SOFCs. • A theoretical model is developed to analyze the new hybrid system performance. • Performance parameters for evaluating the hybrid system are specified. • Feasibility and effectiveness of the proposed system are demonstrated. • Effects of some important parameters on the system performance are discussed. - Abstract: Besides electricity generation, solid oxide fuel cells (SOFCs) produce a significant amount of waste heat, which needs to be immediately removed to ensure the normal operation of SOFCs. If the waste heat is recovered through bottoming thermal devices, the global efficiency of SOFCs can be improved. In this study, a new hybrid system mainly consisting of a thermoelectric generator, a thermoelectric cooler and an SOFC is proposed to recover the waste heat from SOFC for performance enhancement. The thermodynamic and electrochemical irreversible losses in each component are fully considered. An analytical relationship between the SOFC operating current density and the thermoelectric devices dimensionless electric current is derived, from which the range of SOFC operating current density that permits the thermoelectric devices to effectively work is determined. The equivalent power output and efficiency for the hybrid system are specified under different operating current density regions. The feasibility and effectiveness are illustrated by comparing the proposed hybrid system with the stand-alone SOFC. It is found that the power density and efficiency of the proposed system allow 2.3% and 4.6% larger than that of the stand-alone SOFC, respectively. Finally, various parametric analyses are performed to discuss the effects of some design and operation parameters on the hybrid system performance.

Dielectric Constant of Undercooled Water.

Science.gov (United States)

1981-09-01

can or radiation shield, and the experimental stage. The two cans are evacu- -3 ated to about 10 3 mm Hg. The outer can is made of aluminum and is...wrapped with aluminum tubing through which a commercial circulator-cooler pumps a circulating fluid with its tempera- ture controlled to 20 mK between...Control and Measurement System" Strem, R.B., Das, B.K., and Greer, S.C., Rev. Sci. Instrum., in press. 17 Type S-1, Thermometrics , Inc., Ediaon, N.J. 183

Assessment of CO2 emission reduction and identification of CDM potential in a township

Energy Technology Data Exchange (ETDEWEB)

Misra, R.; Aseri, Tarun Kumar; Jamuwa, Doraj Karnal [Department of Mechanical Engineering, Government Engineering College, Ajmer, Rajasthan (India); Bansal, V. [Department of Mechanical Engineering, Government Mahila Engineering College, Ajmer, Rajasthan (India)

2012-11-15

This paper presents the theoretical investigation of CDM opportunity in a township at Jaipur, India. The purpose of study is to identify and analyze the various opportunities viz., installation of solar water heater, energy efficient lighting, energy efficient air conditioners, and energy efficient submersible water pumps in desert coolers and thus achieve a considerable (65.7 %) reduction in GHG emissions. Out of the various opportunities considered, the retrofitting with solar water heater can be recommended for CDM. Though, the retrofitting with energy efficient lighting, energy efficient air conditioners and energy efficient submersible water pumps in desert coolers claimed CO2 emission reduction of 104.84, 25.92, and 36.94 tons per annum, respectively, but the only opportunity which got through CDM was retrofitting with solar water heater claiming 115.70 tCO2 (100 %) emission reductions per annum which could result into net earnings of 115.70 CERs. The simple and discounted payback period for all four project activities are also calculated with and without CDM and tax benefits.

Development and Performance of Alternative Electricity Sector Pathways Subject to Multiple Climate and Water Projections

Science.gov (United States)

Newmark, R. L.; Vorosmarty, C. J.; Miara, A.; Cohen, S.; Macknick, J.; Sun, Y.; Corsi, F.; Fekete, B. M.; Tidwell, V. C.

2017-12-01

Climate change impacts on air temperatures and water availability have the potential to alter future electricity sector investment decisions as well as the reliability and performance of the power sector. Different electricity sector configurations are more or less vulnerable to climate-induced changes. For example, once-through cooled thermal facilities are the most cost-effective and efficient technologies under cooler and wetter conditions, but can be substantially affected by and vulnerable to warmer and drier conditions. Non-thermal renewable technologies, such as PV and wind, are essentially "drought-proof" but have other integration and reliability challenges. Prior efforts have explored the impacts of climate change on electric sector development for a limited set of climate and electricity scenarios. Here, we provide a comprehensive suite of scenarios that evaluate how different electricity sector pathways could be affected by a range of climate and water resource conditions. We use four representative concentration pathway (RCP) scenarios under five global circulation models (GCM) as climate drivers to a Water Balance Model (WBM), to provide twenty separate future climate-water conditions. These climate-water conditions influence electricity sector development from present day to 2050 as determined using the Regional Energy Deployment Systems (ReEDS) model. Four unique electricity sector pathways will be considered, including business-as-usual, carbon cap, high renewable energy technology costs, and coal reliance scenarios. The combination of climate-water and electricity sector pathway scenarios leads to 80 potential future cases resulting in different national and regional electricity infrastructure configurations. The vulnerability of these configurations in relation to climate change (including in-stream thermal pollution impacts and environmental regulations) is evaluated using the Thermoelectric Power and Thermal Pollution (TP2M) model, providing

Mechanical damage and corrosion in the primary system purification cooler

International Nuclear Information System (INIS)

Sainz, R.A.; Fiorini, R.H.; Semino, C.J.

1987-01-01

Through the routine measurements of tritium activity and isotopic content in the exchanger's cooling water, a loss of heavy water was detected. During the decommissioning programmed for October 1986, the equipment was dismantled and the tubes losses were identified through helium fugue tests; subsequently, a 100% inspection of the tubes by atmospheric currents were performed, verifying reductions exceeding 50% of the original width in 70 tubes of the first section at the top plate level. These indications were verified through the study of the two extracted tubes, one of them observing a passing failure where marks appeared at all levels of the support and corrosion plates through splits at the top plates level. The corrosion causes were due to the low cooling flow which results from the primary system's reduction regarding the purification flow design, thus permitting the deposits accumulation. (Author)

Independent criticality safety evaluation of deposits in cooler equipment in Building K-31 at the Oak Ridge K-25 Site, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1996-10-01

This report provides an independent assessment of nuclear criticality issues associated with uranium deposits in the West and East Coolers for the 6A Booster Station in Building K-31 at the Oak Ridge K-25 Site. This assessment investigates the applicability of the initial assumptions used by Lockheed Martin Energy Systems (Energy Systems) and evaluates criticality calculations previously completed by Energy Systems. The calculations were independently verified. Each component was evaluated for its ability to satisfy requirements for subcriticality and meet the double contingency principle. Facility walk downs, detailed neutronics analysis, and fault tree analysis (FTA) were performed. The facility walk downs provided a better understanding of the building condition and status, equipment configuration, and uranium deposit locations. The detailed neutronics analysis focused on system geometry and moderation levels applicable to the individual components. The FTA considered the annual rate of occurrence for the events identified as potential causes of criticality issues. This report also examines the advantages of using this type of evaluation to assess the removal process for additional components and equipment

Determination of benzene, toluene, ethylbenzene and xylene in field and laboratory by means of cold fiber SPME equipped with thermoelectric cooler and GC/FID method

Directory of Open Access Journals (Sweden)

Tajik Leila

2017-09-01

Full Text Available A simple and effective cooling device based on a thermoelectric cooler was applied to cool the SPME fiber. The device was used for quantitative extraction of aromatic hydrocarbons in the air. Several factors such as coating temperature, extraction temperature and relative humidity in the laboratory setting were optimized. Comparison of the results between the cold fiber SPME (CF-SPME and NIOSH 1501 method on standard test atmosphere indicated a satisfactory agreement. The CF-SPME and SPME method were also compared. The results revealed that CF-SPME has the most appropriate outcome for the extraction of aromatic hydrocarbons from the ambient air. The cold fiber SPME technique showed good results for several validation parameters. Under the optimized conditions, the limits of detection (LOD and the limits of quantification (LOQ ranged from 0.00019 to 0.00033 and 0.0006 to 0.001 ng ml−1, respectively. The intra-day relative standard deviation (RSD showed ranging from 4.8 to 10.5%.

Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States†

Science.gov (United States)

Lemons, Angela R.; Hogan, Mary Beth; Gault, Ruth A.; Holland, Kathleen; Sobek, Edward; Olsen-Wilson, Kimberly A.; Park, Yeonmi; Park, Ju-Hyeong; Gu, Ja Kook; Kashon, Michael L.; Green, Brett J.

2017-01-01

Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region. PMID:28091681

Durability of thin-walled concrete structures

International Nuclear Information System (INIS)

Salomon, M.; Gallias, J.L.

1991-01-01

The aim of the present document is to draw up a survey of knowledge of the problems of ageing of reinforced concrete shell structure atmospheric coolers. The exposure conditions are particularly favourable to the induction and development of degradation which, because of the thinness of the reinforced concrete can compromise the stability and the durability of coolers. The study will be axed on the link between the specific characteristics of coolers from the point of view of operation, design and environment, also the durability of reinforced concrete. The set of factors exerting their influence on the reinforced concrete of the shell structure (condensates, rain water, temperature and humidity gradients, dynamic loads, weathering, etc.) is particularly complex. The principal degradation reactions involved are classified according to the chemical and physical action on concrete and on the reinforcement. Particular emphasis is placed on the analysis of degradation processes and the influence of the characteristics of the materials and of the medium. The aim is to determine the mechanisms which present the greatest risk for coolers. The interaction between the degradation to concrete and the change in mechanical characteristics is also studied [fr

Shell coal IGCCS with carbon capture: Conventional gas quench vs. innovative configurations

International Nuclear Information System (INIS)

Martelli, Emanuele; Kreutz, Thomas; Carbo, Michiel; Consonni, Stefano; Jansen, Daniel

2011-01-01

Highlights: → We aim at defining the preferred IGCC design for dry feed gasifiers with CO 2 capture. → Multiple options of syngas cooling, humidification, and WGS are considered. → Plants are designed, modeled, numerically optimized and costs are carefully assessed. → Partial water quench has poor efficiency but low capital cost, then good performance. → Gas quench with the ECN staged WGS design has the best thermo-economic performance. -- Abstract: The Shell coal integrated gasification combined cycle (IGCC) based on the gas quench system is one of the most fuel flexible and energy efficient gasification processes because is dry feed and employs high temperature syngas coolers capable of rising high pressure steam. Indeed the efficiency of a Shell IGCC with the best available technologies is calculated to be 47-48%. However the system looses many percentage points of efficiency (up to 10) when introducing carbon capture. To overcome this penalty, two approaches have been proposed. In the first, the expensive syngas coolers are replaced by a 'partial water quench' where the raw syngas stream is cooled and humidified via direct injection of hot water. This design is less costly, but also less efficient. The second approach retains syngas coolers but instead employs novel water-gas shift (WGS) configurations that requires substantially less steam to obtain the same degree of CO conversion to CO 2 , and thus increases the overall plant efficiency. We simulate and optimize these novel configurations, provide a detailed thermodynamic and economic analysis and investigate how these innovations alter the plant's efficiency, cost and complexity.

Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia.

Science.gov (United States)

Ramos, Jorge E; Pecl, Gretta T; Moltschaniwskyj, Natalie A; Strugnell, Jan M; León, Rafael I; Semmens, Jayson M

2014-01-01

Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters.

DCDM1: Lessons Learned from the World's Most Energy Efficient Data Center

Energy Technology Data Exchange (ETDEWEB)

Sickinger, David E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Van Geet, Otto D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Carter, Thomas [Johnson Controls

2018-05-03

This presentation discusses the holistic approach to design the world's most energy-efficient data center, which is located at the U.S. Department of Energy National Renewable Energy Laboratory (NREL). This high-performance computing (HPC) data center has achieved a trailing twelve-month average power usage effectiveness (PUE) of 1.04 and features a chiller-less design, component-level warm-water liquid cooling, and waste heat capture and reuse. We provide details of the demonstrated PUE and energy reuse effectiveness (ERE) and lessons learned during four years of production operation. Recent efforts to dramatically reduce the water footprint will also be discussed. Johnson Controls partnered with NREL and Sandia National Laboratories to deploy a thermosyphon cooler (TSC) as a test bed at NREL's HPC data center that resulted in a 50% reduction in water usage during the first year of operation. The Thermosyphon Cooler Hybrid System (TCHS) integrates the control of a dry heat rejection device with an open cooling tower.

Water Use in Parabolic Trough Power Plants: Summary Results from WorleyParsons' Analyses

Energy Technology Data Exchange (ETDEWEB)

Turchi, C. S.; Wagner, M. J.; Kutscher, C. F.

2010-12-01

The National Renewable Energy Laboratory (NREL) contracted with WorleyParsons Group, Inc. to examine the effect of switching from evaporative cooling to alternative cooling systems on a nominal 100-MW parabolic trough concentrating solar power (CSP) plant. WorleyParsons analyzed 13 different cases spanning three different geographic locations (Daggett, California; Las Vegas, Nevada; and Alamosa, Colorado) to assess the performance, cost, and water use impacts of switching from wet to dry or hybrid cooling systems. NREL developed matching cases in its Solar Advisor Model (SAM) for each scenario to allow for hourly modeling and provide a comparison to the WorleyParsons results.Our findings indicate that switching from 100% wet to 100% dry cooling will result in levelized cost of electricity (LCOE) increases of approximately 3% to 8% for parabolic trough plants throughout most of the southwestern United States. In cooler, high-altitude areas like Colorado's San Luis Valley, WorleyParsons estimated the increase at only 2.5%, while SAM predicted a 4.4% difference. In all cases, the transition to dry cooling will reduce water consumption by over 90%. Utility time-of-delivery (TOD) schedules had similar impacts for wet- and dry-cooled plants, suggesting that TOD schedules have a relatively minor effect on the dry-cooling penalty.

Variability in cold front activities modulating cool-season evaporation from a southern inland water in the USA

International Nuclear Information System (INIS)

Liu Heping; Blanken, Peter D; Weidinger, Tamas; Nordbo, Annika; Vesala, Timo

2011-01-01

Understanding seasonal variations in the evaporation of inland waters (e.g., lakes and reservoirs) is important for water resource management as well as the prediction of the hydrological cycles in response to climate change. We analyzed eddy covariance-based evaporation measurements from the Ross Barnett Reservoir (32 deg. 26'N, 90 0 02'W; which is always ice-free) in central Mississippi during the cool months (i.e., September-March) of 2007 and 2008, and found that the variability in cold front activities (i.e., passages of cold fronts and cold/dry air masses behind cold fronts) played an important role in modulating the exchange of sensible (H) and latent (λE) heat fluxes. Our analysis showed that 2007's warmer cool season had smaller mean H and λE than 2008's cooler cool season. This implies that the warmer cool season did not accelerate evaporation and heat exchange between the water surface and the atmosphere. Instead, more frequent cold fronts and longer periods of cold/dry air masses behind the cold fronts in 2008 resulted in overall larger H and λE as compared with 2007, this primarily taking the form of sporadic short-term rapid 'pulses' of H and λE losses from the water's surface. These results suggest that future climate-induced changes in frequency of cold fronts and the meteorological properties of the air masses behind cold fronts (e.g., wind speeds, temperature, and humidity), rather than other factors of climate change, would produce significant variations in the water surface's energy fluxes and subsequent evaporation rates.

Coastal circulation and water column properties off Kalaupapa National Historical Park, Molokai, Hawaii, 2008-2010

Science.gov (United States)

Storlazzi, Curt D.; Presto, Katherine; Brown, Eric K.

2011-01-01

More than 2.2 million measurements of oceanographic forcing and the resulting water-column properties were made off U.S. National Park Service's Kalaupapa National Historical Park on the north shore of Molokai, Hawaii, between 2008 and 2010 to understand the role of oceanographic processes on the health and sustainability of the area's marine resources. The tides off the Kalaupapa Peninsula are mixed semidiurnal. The wave climate is dominated by two end-members: large northwest Pacific winter swell that directly impacts the study site, and smaller, shorter-period northeast trade-wind waves that have to refract around the peninsula, resulting in a more northerly direction before propagating over the study site. The currents primarily are alongshore and are faster at the surface than close to the seabed; large wave events, however, tend to drive flow in a more cross-shore orientation. The tidal currents flood to the north and ebb to the south. The waters off the peninsula appear to be a mix of cooler, more saline, deeper oceanic waters and shallow, warmer, lower-salinity nearshore waters, with intermittent injections of freshwater, generally during the winters. Overall, the turbidity levels were low, except during large wave events. The low overall turbidity levels and rapid return to pre-event background levels following the cessation of forcing suggest that there is little fine-grained material. Large wave events likely inhibit the settlement of fine-grained sediment at the site. A number of phenomena were observed that indicate the complexity of coastal circulation and water-column properties in the area and may help scientists and resource managers to better understand the implications of the processes on marine ecosystem health.

Variability of the subtropical mode water in the Southwest Pacific

Science.gov (United States)

Fernandez, Denise; Sutton, Philip; Bowen, Melissa

2017-09-01

The variability of Subtropical Mode Water (STMW) in the Southwest Pacific is investigated using a 28 year-long time series (1986-2014) of high-resolution expendable bathythermograph data north of New Zealand (PX06) and a shorter time series, the Roemmich-Gilson monthly Argo optimal interpolation for the 2004-2014 period. The variability in STMW inventories is compared to the variability in air-sea heat fluxes, mixed layer depths and transport of the East Auckland Current (EAUC) to assess both the atmospheric and oceanic roles influencing the formation and decay of STMW. The STMW north of New Zealand has a short lifespan with little persistence of the water mass from 1 year to the next one. Deeper mixed layers and negative anomalies in surface heat fluxes are correlated with increased formation of STMW. The heat content of the STMW layer is anticorrelated with inventories, particularly during the El Niño years. This suggests that large volumes of STMW are coincident with cooler conditions in the prior winter and less oceanic heat storage. There is significant seasonal and interannual variability in STMW inventories, however there are no trends in STMW properties, including its core layer temperature over the last decade. The variability of the winter EAUC transport is highly correlated with the STMW inventories and thermocline depth in the following spring, suggesting ocean dynamics deepen the thermocline and precondition for deeper mixed layers.

AMATEUR "HAM" RADIO

Science.gov (United States)

these cooler months. Did you know your body can cool 25 times faster in water than in air? That water code at 13 or 20 words-per-minute will no longer be required to obtain amateur radio operating be found by contacting the ARRL or using an Internet search engine to search on such topics as "

Energy Supply System for Industrial Poultry Houses

Directory of Open Access Journals (Sweden)

Sit M.L.

2016-04-01

Full Text Available The gas engine driven carbon dioxide heat pump designed for providing the heat, cold and electricity for industrial poultry house is proposed. The scheme differs from the known by using recuperative heat exchanger installed between the exhaust air duct of poultry house and heat pump evaporator and the heat curtain installed on the air duct after the evaporator. The air coming into the poultry house after the regenerative heat exchanger is supplied to the heat pump gas cooler. The heat pump produces heat of the required parameters of the input air and water for watering of poultry, space heating, etc. Heat pump compressor is driven by gas engine (GPA, by natural gas or biogas. The part of the gas-piston engine heat is used for adjusting the optimal heat pump mode and for regeneration of the absorbent in an evaporative cooler. The proposed technical solution of the above scheme provides a higher COP of the heat pump. Installing of heat curtain does not require the use of non-freezing solution to prevent icing of the air outlet of heat pump evaporator. The latter allows producing, besides electric power and heat, still cold (with the use off the adsorption-refrigerating machine and provide drying air inlet evaporative cooler (if necessary.

A regional neural network model for predicting mean daily river water temperature

Science.gov (United States)

Wagner, Tyler; DeWeber, Jefferson Tyrell

2014-01-01

Water temperature is a fundamental property of river habitat and often a key aspect of river resource management, but measurements to characterize thermal regimes are not available for most streams and rivers. As such, we developed an artificial neural network (ANN) ensemble model to predict mean daily water temperature in 197,402 individual stream reaches during the warm season (May–October) throughout the native range of brook trout Salvelinus fontinalis in the eastern U.S. We compared four models with different groups of predictors to determine how well water temperature could be predicted by climatic, landform, and land cover attributes, and used the median prediction from an ensemble of 100 ANNs as our final prediction for each model. The final model included air temperature, landform attributes and forested land cover and predicted mean daily water temperatures with moderate accuracy as determined by root mean squared error (RMSE) at 886 training sites with data from 1980 to 2009 (RMSE = 1.91 °C). Based on validation at 96 sites (RMSE = 1.82) and separately for data from 2010 (RMSE = 1.93), a year with relatively warmer conditions, the model was able to generalize to new stream reaches and years. The most important predictors were mean daily air temperature, prior 7 day mean air temperature, and network catchment area according to sensitivity analyses. Forest land cover at both riparian and catchment extents had relatively weak but clear negative effects. Predicted daily water temperature averaged for the month of July matched expected spatial trends with cooler temperatures in headwaters and at higher elevations and latitudes. Our ANN ensemble is unique in predicting daily temperatures throughout a large region, while other regional efforts have predicted at relatively coarse time steps. The model may prove a useful tool for predicting water temperatures in sampled and unsampled rivers under current conditions and future projections of climate

Nothing a hot bath won't cure: infection rates of amphibian chytrid fungus correlate negatively with water temperature under natural field settings.

Science.gov (United States)

Forrest, Matthew J; Schlaepfer, Martin A

2011-01-01

Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd). Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis), from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10-50°C), including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75-100% in water 30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications.There must be quite a few things a hot bath won't cure, but I don't know many of them--Sylvia Plath, "The Bell Jar" (1963).

Nothing a hot bath won't cure: infection rates of amphibian chytrid fungus correlate negatively with water temperature under natural field settings.

Directory of Open Access Journals (Sweden)

Matthew J Forrest

Full Text Available Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd. Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis, from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10-50°C, including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75-100% in water 30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications.There must be quite a few things a hot bath won't cure, but I don't know many of them--Sylvia Plath, "The Bell Jar" (1963.

Method for Qualification of Coatings Applied to Wet Surfaces

Science.gov (United States)

2009-12-16

The field application of a pipeline repair or rehabilitation coating usually cannot wait until ambient conditions become optimal. In a humid environment, water can condense on the pipe surface because the pipe surface is usually cooler than the ambie...

Incorporating Water Boiling in the Numerical Modelling of Thermal Remediation by Electrical Resistance Heating

Science.gov (United States)

Molnar, I. L.; Krol, M.; Mumford, K. G.

2017-12-01

Developing numerical models for subsurface thermal remediation techniques - such as Electrical Resistive Heating (ERH) - that include multiphase processes such as in-situ water boiling, gas production and recovery has remained a significant challenge. These subsurface gas generation and recovery processes are driven by physical phenomena such as discrete and unstable gas (bubble) flow as well as water-gas phase mass transfer rates during bubble flow. Traditional approaches to multiphase flow modeling soil remain unable to accurately describe these phenomena. However, it has been demonstrated that Macroscopic Invasion Percolation (MIP) can successfully simulate discrete and unstable gas transport1. This has lead to the development of a coupled Electro Thermal-MIP Model2 (ET-MIP) capable of simulating multiple key processes in the thermal remediation and gas recovery process including: electrical heating of soil and groundwater, water flow, geological heterogeneity, heating-induced buoyant flow, water boiling, gas bubble generation and mobilization, contaminant mass transport and removal, and additional mechanisms such as bubble collapse in cooler regions. This study presents the first rigorous validation of a coupled ET-MIP model against two-dimensional water boiling and water/NAPL co-boiling experiments3. Once validated, the model was used to explore the impact of water and co-boiling events and subsequent gas generation and mobilization on ERH's ability to 1) generate, expand and mobilize gas at boiling and NAPL co-boiling temperatures, 2) efficiently strip contaminants from soil during both boiling and co-boiling. In addition, a quantification of the energy losses arising from steam generation during subsurface water boiling was examined with respect to its impact on the efficacy of thermal remediation. While this study specifically targets ERH, the study's focus on examining the fundamental mechanisms driving thermal remediation (e.g., water boiling) renders

Age dating ground water by use of chlorofluorocarbons (CCl3F and CCl2F2), and distribution of chlorofluorocarbons in the unsaturated zone, Snake River Plain aquifer, Idaho National Engineering Laboratory, Idaho

International Nuclear Information System (INIS)

Busenberg, E.; Weeks, E.P.; Plummer, L.N.; Bartholomay, R.C.

1993-04-01

Detectable concentrations of chlorofluorocarbons (CFC's) were observed in ground water and unsaturated-zone air at the Idaho National Engineering Laboratory (INEL) and vicinity. The recharge ages of waters were determined to be from 4 to more than 50 years on the basis of CFC concentrations and other environmental data; most ground waters have ages of 14 to 30 years. These results indicate that young ground water was added at various locations to the older regional ground water (greater than 50 years) within and outside the INEL boundaries. The wells drilled into the Snake River Plain aquifer at INEL sampled mainly this local recharge. The Big Lost River, Birch Creek, the Little Lost River, and the Mud Lake-Terreton area appear to be major sources of recharge of the Snake River Plain aquifer at INEL. An average recharge temperature of 9.7±1.3 degrees C (degrees Celsius) was calculated from dissolved nitrogen and argon concentrations in the ground waters, a temperature that is similar to the mean annual soil temperature of 9 degrees C measured at INEL. This similarity indicates that the aquifer was recharged at INEL and not at higher elevations that would have cooler soil temperatures than INEL. Soil-gas concentrations at Test Area North (TAN) are explained by diffusion theory

77 FR 76825 - Energy Conservation Program: Certification of Commercial and Industrial HVAC, Refrigeration and...

Science.gov (United States)

2012-12-31

... Energy Conservation Program: Certification of Commercial and Industrial HVAC, Refrigeration and Water... provisions for commercial refrigeration equipment; commercial heating, ventilating, air-conditioning (HVAC...; commercial HVAC equipment; commercial WH equipment; and walk-in coolers and freezers (June 30 Final Rule). 76...

Control systems for condensing flue-gas coolers related to natural-gas-fired heating plants

International Nuclear Information System (INIS)

Krighaar, M.; Paulsen, O.

1992-01-01

A theoretical study is made of the enthalpy-efficiency for a water-cooled heat exchanger added to a natural gas-fired boiler. Under varying conditions of both water flow and temperature and flue-gas flow and temperature, both in condensing and non-condensing mode, the efficiency seems to be constant. The result is very useful for comparison between two different working conditions. The efficiency is used to calculate the savings achieved for a district heating plant by using a heat exchanger. The energy economic calculations are also helpful for estimating the most appropriate size of heat exchanger. The annual savings are calculated by means of data regarding heat production, flue gas temperature and water return temperature. The savings achieved by using different connection principles such as bypass, reheating and controlled water temperature are also calculated. (author)

Methodology for Outdoor Water Savings Model and Spreadsheet Tool for U.S. and Selected States

Energy Technology Data Exchange (ETDEWEB)

Williams, Alison A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Yuting [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dunham, Camilla [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fuchs, Heidi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Stratton, Hannah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-07-31

Green lawns and landscaping are archetypical of the populated American landscape, and typically require irrigation, which corresponds to a significant fraction of residential, commercial, and institutional water use. In North American cities, the estimated portion of residential water used for outdoor purposes ranges from 22-38% in cooler climates up to 59-67% in dry and hot environments, while turfgrass coverage within the United States spans 11.1-20.2 million hectares (Milesi et al. 2009). One national estimate uses satellite and aerial photography data to develop a relationship between impervious surface and lawn surface area, yielding a conservative estimate of 16.4 (± 3.6) million hectares of lawn surface area in the United States—an area three times larger than that devoted to any irrigated crop (Milesi et al. 2005). One approach that holds promise for cutting unnecessary outdoor water use is the increased deployment of “smart” irrigation controllers to increase the water efficiency of irrigation systems. This report describes the methodology and inputs employed in a mathematical model that quantifies the effects of the U.S. Environmental Protection Agency’s WaterSense labeling program for one such type of controller, weather-based irrigation controllers (WBIC). This model builds off that described in “Methodology for National Water Savings Model and Spreadsheet Tool–Outdoor Water Use” and uses a two-tiered approach to quantify outdoor water savings attributable to the WaterSense program for WBIC, as well as net present value (NPV) of that savings. While the first iteration of the model assessed national impacts using averaged national values, this version begins by evaluating impacts in three key large states that make up a sizable portion of the irrigation market: California, Florida, and Texas. These states are considered to be the principal market of “smart” irrigation controllers that may result in the bulk of national savings. Modeled

ICE911 Research: Floating Safe Inert Materials to Preserve Ice and Conserve Water in Order to Mitigate Climate Change Impacts

Science.gov (United States)

Field, L. A.; Manzara, A.; Chetty, S.; Venkatesh, S.; Scholtz, A.

2015-12-01

Ice911 Research has conducted years of field testing to develop and test localized reversible engineering techniques to mitigate the negative impacts of polar ice melt. The technology uses environmentally safe materials to reflect energy in carefully selected, limited areas from summertime polar sun. The technology is now being adapted to help with California's drought. We have tested the albedo modification technique on a small scale over seven Winter/Spring seasons at sites including California's Sierra Nevada Mountains, a Canadian lake, and a small artificial pond in Minnesota about 100 ft in diameter and 6 ft deep at the center, using various materials and an evolving array of instrumentation. On the pond in Minnesota, this year's test results for ice preservation, using hollow glass spheres deployed over our largest test areas yet, showed that glass bubbles can provide an effective material for increasing albedo, significantly reducing the melting rate of ice. This year Ice911 also undertook its first small Arctic field test in Barrow, Alaska on a lake in Barrow's BEO area, and results are still coming in. The technology that Ice911 has been developing for ice preservation has also been shown to keep small test areas of water cooler, in various small-scale tests spanning years. We believe that with some adaptations of the technology, the materials can be applied to reservoirs and lakes to help stretch these precious resources further in California's ongoing drought. There are several distinct advantages for this method over alternatives such as large reverse osmosis projects or building new reservoirs, which could possibly allow a drought-stricken state to build fewer of these more-costly alternatives. First, applying an ecologically benign surface treatment of Ice911's materials can be accomplished within a season, at a lower cost, with far less secondary environmental impact, than such capital-and-time-intensive infrastructure projects. Second, keeping

Influence of biofilms on iron and manganese deposition in drinking water distribution systems.

Science.gov (United States)

Ginige, Maneesha P; Wylie, Jason; Plumb, Jason

2011-02-01

Although health risk due to discoloured water is minimal, such water continues to be the source of one of the major complaints received by most water utilities in Australia. Elevated levels of iron (Fe) and/or manganese (Mn) in bulk water are associated with discoloured water incidents. The accumulation of these two elements in distribution systems is believed to be one of the main causes for such elevated levels. An investigation into the contribution of pipe wall biofilms towards Fe and Mn deposition, and discoloured water events is reported in this study. Eight laboratory-scale reactors were operated to test four different conditions in duplicate. Four reactors were exposed to low Fe (0.05 mg l(-1)) and Mn (0.02 mg l(-1)) concentrations and the remaining four were exposed to a higher (0.3 and 0.4 mg l(-1) for Fe and Mn, respectively) concentration. Two of the four reactors which received low and high Fe and Mn concentrations were chlorinated (3.0 mg l(-1) of chlorine). The biological activity (measured in terms of ATP) on the glass rings in these reactors was very low (∼1.5 ng cm(-2) ring). Higher concentrations of Fe and Mn in bulk water and active biofilms resulted in increased deposition of Fe and Mn on the glass rings. Moreover, with an increase in biological activity, an increase in Fe and Mn deposition was observed. The observations in the laboratory-scale experiments were in line with the results of field observations that were carried out using biofilm monitors. The field data additionally demonstrated the effect of seasons, where increased biofilm activities observed on pipe wall biofilms during late summer and early autumn were found to be associated with increased deposition of Fe and Mn. In contrast, during the cooler months, biofilm activities were a magnitude lower and the deposited metal concentrations were also significantly less (ie a drop of 68% for Fe and 86% for Mn). Based on the laboratory-scale investigations, detachment of pipe wall

Water temperature change caused by reservoirs; Alteracion que presenta la temperatura del agua por la existencia de embalses

Energy Technology Data Exchange (ETDEWEB)

Val, Rafael [Universidad Nacional Autonoma de Mexico (Mexico); Ninerola, Daniel; Pomares, Juan; Dolz, Jose [Universidad Politecnica de Cataluna (Spain); Armengol, Juan [Universidad de Barcelona (Spain)

2006-01-15

The water of a river exchanges heat with the atmosphere and with the riverbed; this process can reach its equilibrium along a stretch of river with similar geologic and climatic characteristics. This behavior can be modified by artificial effects; for example the use of the river water as a cooler in thermal power stations or in reservoir existent. The case of regions with Mediterranean climate, where the reservoirs here studied are found, the effects of changes in the natural thermal regime caused by dams and reservoirs are evaluated through: seasonal and daily thermal constancies, warmer winter water temperatures and reduced summer water temperature. Downstream from the power station or downstream the dam, the water temperature will evolve in such a way as to achieve the environmental equilibrium. The water temperature is a main factor in the ecology of the river; already it conditions in importance the life in fluvial reservoirs. [Spanish] El agua de un rio mantiene un intercambio de calor con la atmosfera y con el fondo. Este proceso puede alcanzar su equilibrio siempre y cuando las caracteristicas geologicas y climaticas a lo largo de un tramo del rio sean similares. Sin embargo, el comportamiento termico del rio puede ser alterado por los diversos usos del agua, como la refrigeracion de centrales termoelectricas, o por el almacenamiento del agua debido a la existencia de una presa. En el caso de las regiones con clima mediterraneo, donde se encuentran los embalses aqui estudiados, los efectos de las alteraciones en el regimen termico, resultado a su vez de dichos embalses, provocan una tendencia a la constancia termica estacional (elevacion de las temperaturas invernales y disminucion de las temperaturas estivales) y tambien un aumento de la uniformidad diaria. Aguas abajo de las termoelectricas o presas, la temperatura del agua evoluciona de tal forma que tiende a lograr el equilibrio con el medio ambiente.

Analyse numérique des dynamiques d'obstruction dans les refroidisseurs Joule-Thomson micro-usinés

NARCIS (Netherlands)

Cao, H. S.; Vanapalli, S.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J.M.

2017-01-01

Micromachined Joule–Thomson (JT) coolers are of interest for cooling small electronic devices. The long-term performance of JT microcoolers is limited by the clogging phenomenon caused by the deposition of water molecules present as impurity in the working fluid. This work investigates the clogging

Water use, root activity and deep drainage within a perennial legume-grass pasture: A case study in southern inland Queensland, Australia

Directory of Open Access Journals (Sweden)

A. Nahuel A. Pachas

2016-09-01

Full Text Available Water use and depth of water extraction of leucaena (Leucaena leucocephala and Rhodes grass (Chloris gayana pasture, irrigated with desalinated coal seam water (a by-product of the coal seam gas industry, were monitored to provide background information on root activity, spatial and temporal water use and deep drainage over a 757-day period from August 2011 to August 2013. Methodology comprised measurement of soil water from surface to 4 m depth using 8 EnviroSCAN probes connected to dataloggers positioned within leucaena twin rows and within the Rhodes grass inter-row. Just over 581,000 individual moisture measurements were collated and are reported here. Water extraction (and by inference root activity of leucaena and Rhodes grass showed marked seasonal fluctuation with deepest and highest water extraction occurring during the first growing season; water extraction was greatly diminished during the following drier and cooler seasons due to the negative influences of lower soil moisture contents, lower temperatures and increased defoliation on pasture growth. The highest values of deep drainage below 4 m depth occurred when high rainfall events corresponded with high soil water storage in the entire profile (0–4 m depth. Given that water usage by both leucaena and Rhodes grass was greatest in the upper layers of soil (<1.5 m, future research should focus on how the level of competitive interaction might be managed by choice of row spacing and frequency of irrigation. Further studies are needed, including: (a physical sampling to determine the depth of active roots; (b how defoliation affects rooting behaviours and water use of leucaena; and (c modelling of the water and salt balances of leucaena and grass inter-row systems using data from this study, with various levels of irrigation, to investigate the risks of deep drainage over an extended climate sequence.Keywords: Active rooting depth, agroforestry, Chloris gayana, Leucaena leucocephala

The Little Ice Age was 1.0-1.5 °C cooler than current warm period according to LOD and NAO

Science.gov (United States)

Mazzarella, Adriano; Scafetta, Nicola

2018-02-01

We study the yearly values of the length of day (LOD, 1623-2016) and its link to the zonal index (ZI, 1873-2003), the Northern Atlantic oscillation index (NAO, 1659-2000) and the global sea surface temperature (SST, 1850-2016). LOD is herein assumed to be mostly the result of the overall circulations occurring within the ocean-atmospheric system. We find that LOD is negatively correlated with the global SST and with both the integral function of ZI and NAO, which are labeled as IZI and INAO. A first result is that LOD must be driven by a climatic change induced by an external (e.g. solar/astronomical) forcing since internal variability alone would have likely induced a positive correlation among the same variables because of the conservation of the Earth's angular momentum. A second result is that the high correlation among the variables implies that the LOD and INAO records can be adopted as global proxies to reconstruct past climate change. Tentative global SST reconstructions since the seventeenth century suggest that around 1700, that is during the coolest period of the Little Ice Age (LIA), SST could have been about 1.0-1.5 °C cooler than the 1950-1980 period. This estimated LIA cooling is greater than what some multiproxy global climate reconstructions suggested, but it is in good agreement with other more recent climate reconstructions including those based on borehole temperature data.

Soil-water flux in the southern Great Basin, United States: temporal and spatial variations over the last 120,000 years

International Nuclear Information System (INIS)

Tyler, S.W.; Chapman, J.B.; Conrad, S.H.; Hammermeister, D.P.; Blout, D.O.; Miller, J.J.; Sully, M.J.; Ginanni, J.M.

1996-01-01

The disposal of hazardous and radioactive waste in arid regions requires a thorough understanding of the occurrence of soil-water flux and recharge. Soil-water chemistry and isotopic data are presented from three deep vadose zone boreholes (> 230 m) at the Nevada Test Site, located in the Great Basin geographic province of the southwestern United States, to quantify soil-water flux and its relation to climate. The low water contents found in the soils significantly reduce the mixing of tracers in the subsurface and provide a unique opportunity to examine the role of climate variation on recharge in arid climates. Tracing techniques and core data are examined in this work to reconstruct the paleohydrologic conditions existing in the vadose zone well beyond the timescales typically investigated. Stable chloride and chlorine 36 profiles indicate that the soil waters deep in the vadose zone range in age from approximately 20,000 to 120,000 years. Secondary chloride bulges that are present in two of the three profiles support the concept of recharge occurring at or near the last two glacial maxima, when the climate of the area was considerably wetter and cooler. The stable isotopic composition of the soil water in the profiles is significantly more depleted in heavy isotopes than is modern precipitation, suggesting that recharge under the current climate is not occurring at this arid site. Past and present recharge appears to have been strongly controlled by surface topography, with increased incidence of recharge where runoff from the surrounding mountains may have been concentrated. The data obtained from this detailed drilling and sampling program shed new light on the behavior of water in thick vadose zones and, in particular, show the sensitivity of arid regions to the extreme variations in climate experienced by the region over the last two glacial maxima

Performance comparison of a silica gel-water and activated carbon-methanol two beds adsorption chillers

Directory of Open Access Journals (Sweden)

Szelągowski Adam

2017-01-01

Full Text Available The aim of the study is to compare the efficiency of adsorption refrigerating equipment working with different working pairs. Adsorption cooling devices can operate with a relatively low temperature of heat sources while consuming only a small amount of electricity for the operation of auxiliary equipment. Refrigerants used in adsorption devices are substances that do not have a negative impact on the environment. All that makes that adsorption refrigeration seems to be a good solution for utilizing renewable and waste heat sources for cold production. To carry out the experiment the adsorption cooling device has been developed and researched in Institute of Heat Engineering at Warsaw University of Technology. The test bench consisted of two cylindrical adsorbers, condenser, evaporator, oil heater and two oil coolers. In order to perform the correct action it has been developed and implemented special control algorithm device, allowed to keep the temperature in the evaporator at a preset level. The unit tested for two sorption pairs: activated carbon – methanol, and silica gel – water. For activated carbon - methanol working pair it was obtained energy efficiency rating (EER equals to 0.14 and specific cooling power (SPC of 16 W/kg. For silica gel - water EER of refrigeration unit was 0.25 and SPC was equal to 208 W/kg.

Engineering solutions to improve environmental characteristics of coke-chemical industry

Energy Technology Data Exchange (ETDEWEB)

Lavrov, K G; Cherkashina, O I; Pushkarev, G P; Pakhomov, V A; Florinskii, N V; Oleinik, K P; Likhogub, E P; Dorfman, G A; Gorelik, Ya L; Vorona, V K

1979-06-01

In future projects consideration will be given to reduction of air and water pollution. Escape of dust from coke-batteries and coal preparation plants will be stopped by using hermetic enclosures with aspirators. Effluent gases and vapours will be curbed by using more efficient scrubbers and flare systems. Effluent waters will be treated at two-stage flotation stations and recycled to 95% as cooling and utility water. Cooling water consumption will be reduced by the use of air coolers. Pollution monitoring will be improved.

Distillation irrigation: a low-energy process for coupling water purification and drip irrigation

Science.gov (United States)

Constantz, J.

1989-01-01

A method is proposed for combining solar distillation and drip irrigation to simultaneously desalinize water and apply this water to row crops. In this paper, the basic method is illustrated by a simple device constructed primarily of sheets of plastic, which uses solar energy to distill impaired water and apply the distillate to a widely spaced row crop. To predict the performance of the proposed device, an empirical equation for distillate production, dp, is developed from reported solar still production rates, and a modified Jensen-Haise equation is used to calculate the potential evapotranspiration, et, for a row crop. Monthly values for et and dp are calculated by using a generalized row crop at five locations in the Western United States. Calculated et values range from 1 to 22 cm month-1 and calculated dp values range from 2 to 11 cm month-1, depending on the location, the month, and the crop average. When the sum of dp plus precipitation, dp + P, is compared to et for the case of 50% distillation irrigation system coverage, the results indicate that the crop's et is matched by dp + P, at the cooler locations only. However, when the system coverage is increased to 66%, the crop's et is matched by dp + P even at the hottest location. Potential advantages of distillation irrigation include the ability: (a) to convert impaired water resources to water containing no salts or sediments; and (b) to efficiently and automatically irrigate crops at a rate that is controlled primarily by radiation intensities. The anticipated disadvantages of distillation irrigation include: (a) the high costs of a system, due to the large amounts of sheeting required, the short lifetime of the sheeting, and the physically cumbersome nature of a system; (b) the need for a widely spaced crop to reduce shading of the system by the crop; and (c) the production of a concentrated brine or precipitate, requiring proper off-site disposal. ?? 1989.

Assessment of water/glass interactions in waste glass melter operation

International Nuclear Information System (INIS)

Postma, A.K.; Chapman, C.C.; Buelt, J.L.

1980-04-01

A study was made to assess the possibility of a vapor explosion in a liquid-fed glass melter and during off-standard conditions for other vitrification processes. The glass melter considered is one designed for the vitrification of high-level nuclear wastes and is comprised of a ceramic-lined cavity with electrodes for joule heating and processing equipment required to add feed and withdraw glass. Vapor explosions needed to be considered because experience in other industrial processes has shown that violent interactions can occur if a hot liquid is mixed with a cooler, vaporizable liquid. Available experimental evidence and theoretical analyses indicate that destructive glass/water interactions are low probability events, if they are possible at all. Under standard conditions, aspects of liquid-fed melter operation which work against explosive interactions include: (1) the aqueous feed is near its boiling point; (2) the feed contains high concentrations of suspended particles; (3) molten glass has high viscosity (greater than 20 poise); and (4) the glass solidifies before film boiling can collapse. While it was concluded that vapor explosions are not expected in a liquid-fed melter, available information does not allow them to be ruled out altogether. Several precautionary measures which are easily incorporated into melter operation procedures were identified and additional experiments were recommended

The global impact of alien trout species — a review; with reference ...

African Journals Online (AJOL)

Brown trout, Salmo trutta, and rainbow trout, Oncorhynchus mykiss, were first introduced into South African waters as angling species in the later part of the nineteenth century, when environmental impact studies were neither considered nor undertaken. Trout have since been introduced mainly into the cooler upper ...

Impact of individual and worksite environmental factors on water and sugar-sweetened beverage consumption among overweight employees.

Science.gov (United States)

Davy, Brenda M; You, Wen; Almeida, Fabio; Wall, Sarah; Harden, Samantha; Comber, Dana L; Estabrooks, Paul A

2014-05-01

The worksite environment may influence employees' dietary behaviors. Consumption of water and sugar-sweetened beverages (SSBs) affect weight management; however, little research has evaluated the influence of worksite factors on beverage consumption. Our purpose was to determine whether individual and worksite factors are associated with water and SSB intake among overweight and obese employees. Data were collected as part of baseline assessments for a worksite-based, weight-management intervention trial. Height and weight of participants (N = 1,482; 74% female; mean age = 47 y [standard deviation (SD) = 11 y]; mean weight = 208 lbs [SD = 46 lbs]) were assessed, and participants completed a validated beverage intake questionnaire. Environmental characteristics of worksites (N = 28) were audited. A qualitative comparative analysis (QCA) was used to identify worksite conditions that may support healthier beverage intake patterns. Most participants were white (75% of sample) with at least some college education or a college degree (approximately 82% of sample). Mean water and SSB intake were 27 fl oz (SD = 18 fl oz) and 17 fl oz (SD = 18 fl oz), respectively; SSB intake (191 kcal [SD = 218 kcal]) exceeded the recommended discretionary energy intake. Statistical models did not identify any significant predictors of water intake. Female sex and increasing level of education and household income were associated with lower SSB intake; baseline body weight and greater number of worksite water coolers and vending machines were associated with higher SSB intake. The QCA identified worksite type (ie, not manual labor) as a condition necessary for healthier beverage consumption; a worksite break policy of 2 or more per day may lead to unhealthy beverage consumption. Lower SSB consumption was noted among older participants, female participants, and among participants with higher education and income levels. Workplace factors influence beverage consumption among overweight

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

International Nuclear Information System (INIS)

He Suyan; Li Yunfei

2008-01-01

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1 deg. C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

Energy Technology Data Exchange (ETDEWEB)

He, Su-Yan [School of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071 (China); Li, Yun-Fei [Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University (China)

2008-10-15

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1{sup o}C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data. (author)

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

Energy Technology Data Exchange (ETDEWEB)

He Suyan [School of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071 (China)], E-mail: hesuyan67829@sina.com; Li Yunfei [Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University (China)

2008-10-15

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1 deg. C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data.

Initial observation of upwelling along east coast of Peninsular Malaysia musica-gratis.softonic.it/ >musica gratis

Science.gov (United States)

Akhir, M.; Tanggang, F.

2013-12-01

There is no published evidence of upwelling in coastal area along the east coast of Peninsular Malaysia. However numbers of recent cruise data collected during the southwest monsoon found features of thermocline lifting and isolated cooler temperature water along the coast, These sign was observed along the 104°E from numbers of parallel transects. To confirm the presence of upwelling, satellite remote sensing data was used, and numerical model experiments were conducted. Cooler sea-surface temperature along the coast was observed from both in-situ and satellite data, while upward movement in the vertical profiles agreed with the location of upwelling from both in-situ and satellite data. Moreover, these data also show that the upwelled water band along the 104°E longitude stretch approximately 650 km long. Initially, southwesterly wind during this season is believed to be the important mechanism that contributed to this wind-induced Ekman upwelling. musica-gratis.softonic.it/ >musica gratis

LMTD Design Methodology Assessment of Spiral Tube Heat Exchanger under the S-CO2 cycle operating condition

International Nuclear Information System (INIS)

Jung, Hwa Young; Lee, Jeong Ik; Ahn, Yoon Han

2013-01-01

The advantages of PCHE are compact high pressure difference endurance high temperature operation. However, PCHE is quite expensive and the resistance to the fast thermal cycling is questionable. In order to overcome this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is considering an alternative for the PCHE. Currently KAIST research team is using a Spiral Tube Heat Exchanger (STHE) of Sentry Equipment Corp. as a pre cooler in the SCO 2 PE facility. A STHE is relatively cheap but the operating pressure and temperature are acceptable for utilizing it as a pre cooler. A STHE is consisted of spiral shaped tubes (hot side i.e. S-CO 2 ) immersed in a shell (cold side i.e. water). This study is aimed at whether the logarithmic mean temperature difference (LMTD) heat exchanger design methodology is acceptable for designing the S-CO 2 cycle pre cooler. This is because the LMTD method usually assumes a constant specific heat, but the pre cooler in the S-CO 2 cycle operates at the nearest point to the critical point where a dramatic change in properties is expected. Experimentally obtained data are compared to the vendor provided technical specification based on the LMTD method. The detailed specifications provided by the vendor are listed in Table 1

LMTD Design Methodology Assessment of Spiral Tube Heat Exchanger under the S-CO{sub 2} cycle operating condition

Energy Technology Data Exchange (ETDEWEB)

Jung, Hwa Young; Lee, Jeong Ik; Ahn, Yoon Han [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2013-05-15

The advantages of PCHE are compact high pressure difference endurance high temperature operation. However, PCHE is quite expensive and the resistance to the fast thermal cycling is questionable. In order to overcome this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is considering an alternative for the PCHE. Currently KAIST research team is using a Spiral Tube Heat Exchanger (STHE) of Sentry Equipment Corp. as a pre cooler in the SCO{sub 2}PE facility. A STHE is relatively cheap but the operating pressure and temperature are acceptable for utilizing it as a pre cooler. A STHE is consisted of spiral shaped tubes (hot side i.e. S-CO{sub 2}) immersed in a shell (cold side i.e. water). This study is aimed at whether the logarithmic mean temperature difference (LMTD) heat exchanger design methodology is acceptable for designing the S-CO{sub 2} cycle pre cooler. This is because the LMTD method usually assumes a constant specific heat, but the pre cooler in the S-CO{sub 2} cycle operates at the nearest point to the critical point where a dramatic change in properties is expected. Experimentally obtained data are compared to the vendor provided technical specification based on the LMTD method. The detailed specifications provided by the vendor are listed in Table 1.

Performance analysis of proposed hybrid air conditioning and humidification–dehumidification systems for energy saving and water production in hot and dry climatic regions

International Nuclear Information System (INIS)

Nada, S.A.; Elattar, H.F.; Fouda, A.

2015-01-01

Highlights: • Integrative air-conditioning (A/C) and humidification–dehumidification desalination systems are proposed. • Effects of operating parameters on the proposed systems are investigated. • System configurations that have the highest fresh water production rate, power saving and total cost saving are identified. - Abstract: Performance of integrative air-conditioning (A/C) and humidification–dehumidification desalination systems proposed for hot and dry climatic regions is theoretically investigated. The proposed systems aim to energy saving and systems utilization in fresh water production. Four systems with evaporative cooler and heat recovery units located at different locations are proposed, analyzed and evaluated at different operating parameters (fresh air ratio, supply air temperature and outside air wet bulb temperature). Other two basic systems are used as reference systems in proposed systems assessment. Fresh water production rate, A/C cooling capacity, A/C electrical power consumption, saving in power consumptions and total cost saving (TCS) parameters are used for systems evaluations and comparisons. The results show that (i) the fresh water production rates of the proposed systems increase with increasing fresh air ratio, supply air temperature and outdoor wet bulb temperature, (ii) powers saving of the proposed systems increase with increasing fresh air ratio and supply air temperature and decreasing of the outdoor air wet bulb temperature, (iii) locating the evaporative cooling after the fresh air mixing remarkably increases water production rate, and (vi) incorporating heat recovery in the air conditioning systems with evaporative cooling may adversely affect both of the water production rate and the total cost saving of the system. Comparison study has been presented to identify systems configurations that have the highest fresh water production rate, highest power saving and highest total cost saving. Numerical correlations for

Annual Tropical Cyclone Report, 1984.

Science.gov (United States)

1984-01-01

5 2. Reconnaissance Availabilit ---------------------------------S5 3. Aircraft Reconnaissance Summary--------------------------- 5 4. Satellite...similar to that described by Sadler (1976). an MLSP of 1004 mb with estimated maximum While remaining over water its entire life, surface winds of 25 kt...until late on the Ed transited the East China Sea, entrainment 24th that the cloud mass became detached of drier air and passage over cooler waters from

Daily and seasonal trends of electricity and water use on pasture-based automatic milking dairy farms.

Science.gov (United States)

Shortall, J; O'Brien, B; Sleator, R D; Upton, J

2018-02-01

The objective of this study was to identify the major electricity and water-consuming components of a pasture-based automatic milking (AM) system and to establish the daily and seasonal consumption trends. Electricity and water meters were installed on 7 seasonal calving pasture-based AM farms across Ireland. Electricity-consuming processes and equipment that were metered for consumption included milk cooling components, air compressors, AM unit(s), auxiliary water heaters, water pumps, lights, sockets, automatic manure scrapers, and so on. On-farm direct water-consuming processes and equipment were metered and included AM unit(s), auxiliary water heaters, tubular coolers, wash-down water pumps, livestock drinking water supply, and miscellaneous water taps. Data were collected and analyzed for the 12-mo period of 2015. The average AM farm examined had 114 cows, milking with 1.85 robots, performing a total of 105 milkings/AM unit per day. Total electricity consumption and costs were 62.6 Wh/L of milk produced and 0.91 cents/L, respectively. Milking (vacuum and milk pumping, within-AM unit water heating) had the largest electrical consumption at 33%, followed by air compressing (26%), milk cooling (18%), auxiliary water heating (8%), water pumping (4%), and other electricity-consuming processes (11%). Electricity costs followed a similar trend to that of consumption, with the milking process and water pumping accounting for the highest and lowest cost, respectively. The pattern of daily electricity consumption was similar across the lactation periods, with peak consumption occurring at 0100, 0800, and between 1300 and 1600 h. The trends in seasonal electricity consumption followed the seasonal milk production curve. Total water consumption was 3.7 L of water/L of milk produced. Water consumption associated with the dairy herd at the milking shed represented 42% of total water consumed on the farm. Daily water consumption trends indicated consumption to be lowest in

Water mass characteristic in the outflow region of the Indonesian throughflow during and post 2016 negative Indian ocean dipole event

Science.gov (United States)

Bayhaqi, A.; Iskandar, I.; Surinati, D.; Budiman, A. S.; Wardhana, A. K.; Dirhamsyah; Yuan, D.; Lestari, D. O.

2018-05-01

Strong El Niño and positive Indian Ocean Dipole (pIOD) events in 2015/2016 followed by relatively strong negative Indian Ocean Dipole (nIOD) and weak La Niña in 2016 events have affected hydrography conditions in the Indonesian Throughflow (ITF) region. Two research cruises were conducted using RV Baruna Jaya VIII in August and November 2016. These cruises aim to evaluate possible impact of those two climate mode events on the water mass characteristic in the outflow region of the ITF. Hydrographic data from those two cruises were combined with the sea surface temperature (SST) from the Advanced Very High Resolution Radiometer (AVHRR) and surface wind data from the European Centre for Medium-Range Weather Forecasts (ECMWF). The results showed that in the 2016 anomaly year, the cooler sea surface temperature was observed during the negative IOD (nIOD) event while the warmer temperature was found in the post of nIOD event. The observed water mass characteristics in the outflow region of the ITF revealed that the upper layer was dominated by the Indian Ocean water mass, while the Pacific Ocean water mass was observed in the deeper layer. The observed current data across the Sumba Strait showed that the South Java Coastal Current (SJCC) was observed in the upper layer, propagating eastward toward the Savu Sea. A few days later, the observed currents in the upper layer of the Ombai Strait revealed the ITF flow towards the Indian Ocean. Meanwhile, the lower layer showed an eastward flow towards the Ombai Strait.

Ultrafast harmonic rf kicker design and beam dynamics analysis for an energy recovery linac based electron circulator cooler ring

Directory of Open Access Journals (Sweden)

Yulu Huang

2016-08-01

Full Text Available An ultrafast kicker system is being developed for the energy recovery linac (ERL based electron circulator cooler ring (CCR in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously named MEIC. In the CCR, the injected electron bunches can be recirculated while performing ion cooling for 10–30 turns before the extraction, thus reducing the recirculation beam current in the ERL to 1/10−1/30 (150  mA-50  mA of the cooling beam current (up to 1.5 A. Assuming a bunch repetition rate of 476.3 MHz and a recirculating factor of 10 in the CCR, the kicker is required to operate at a pulse repetition rate of 47.63 MHz with pulse width of around 2 ns, so that only every 10th bunch in the CCR will experience a transverse kick while the rest of the bunches will not be disturbed. Such a kicker pulse can be synthesized by ten harmonic modes of the 47.63 MHz kicker pulse repetition frequency, using up to four quarter wavelength resonator (QWR based deflecting cavities. In this paper, several methods to synthesize such a kicker waveform will be discussed and a comparison of their beam dynamics performance is made using ELEGANT. Four QWR cavities are envisaged with high transverse shunt impedance requiring less than 100 W of total rf power for a Flat-Top kick pulse. Multipole fields due to the asymmetry of this type of cavity are analyzed. The transverse emittance growth due to the sextupole component is simulated in ELEGANT. Off-axis injection and extraction issues and beam optics using a multicavity kick-drift scheme will also be discussed.

Contract Management Process and Mentorship Analysis of United States Special Operations Command’s (USSOCOM) Special Operations Acquisition and Logistics Directorate of Procurement (SOAL-K)

Science.gov (United States)

2009-12-01

classroom instruction and by reading printed text and remain comfortable with both. They are verbally adept.  Gen X-ers (born 1965-1979)—Adapt easily to...11. Peer Assist 12. Podcasts 13. Retrospect (team meeting held after an event) 14. Storytelling (water-cooler conversation) 15. Wikis (web

Coolers of the emergency cooling system for VVER 1000 Temelin

International Nuclear Information System (INIS)

Prchal, J.

1997-01-01

The fabrication of 6 heat exchangers for the new nuclear power plant at Temelin was successfully finished by the Kralovopolska Company in August 1993. All parts of the emergency cooling exchangers that will get into contact with the water coolant will be fitted with two-phase steel. The exchanger design is based on the AO 257 572 heat exchanger with helical partitions. The advantage of this patented solution is a significant intensification of the heat exchange at a minimum loss in pressure, which makes it possible to use tubes of a smaller diameter. The simplicity of this solution leads to a reduction in the number and length of welded joints and thus increases the reliability. (M.D.)

COSY Juelich - a cooler synchrotron for unpolarized and polarized medium-energy studies

International Nuclear Information System (INIS)

Seyfarth, H.

2001-01-01

Full text: The Forschungszentrum Juelich (Research Center Juelich) is one of the sixteen national research institutions in the 'Hermann von Helmholtz Association of German Research Centers'. It is dedicated to fundamental and applied research and development which can be summarized under five priorities: (i) structure of matter and materials research, (ii) information technology, (iii) life sciences, (iv) environment precaution research, and (v) energy technology. As one of the institutes within (i). the Institut fur Kernphysik (Institute for Nuclear Research) operates the COSY cooler synchrotron which allows to accelerate unpolarized and polarized protons and deuterons to the maximum momentum of 3450 MeV/c (2640 MeV and 2050 MeV kinetic energy for protons and deuterons, respectively). At low energy electron cooling can be used for beam preparation, whereas stochastic cooling can be applied to the accelerated beam. In the first years of operation since 1993 the experiments have been performed with the unpolarized proton beam. Since 1997 the polarized proton beam is available with increasing intensity and a typical degree of polarization of about 75 % up to the maximum beam energy. In 2000 the first unpolarized deuteron beam could be accelerated and stored at the maximum energy. Four target places exist for the internal experiments PISA. EDDA, COSY-II, and ANKE which use the circulating beam with thin solid strip or fiber targets and gas targets. The four experiments TOF, MOMO, GEM, NESSI, and JESSICA are using external beams. The programs of the experiments JESSICA (Juelich Experimental Spallation Setup in the COSY Area), NESSI (Neutron Scintillator and Silicon), and PISA (Proton Induced Spallation) aim at the measurement of data needed or the design of the target station of the planned European Spallation neutron Source (ESS). The set-up of PISA is replacing the earlier experiment COSY-13 which successfully completed its investigations on the production of

New arrangement for the air cleanup system to recover tritium

International Nuclear Information System (INIS)

Nishikawa, Masabumi; Takahashi, Kohsaku; Munakata, Kenzo; Fukada, Satoshi; Kotoh, Kenji; Takeishi, Toshiharu

1997-01-01

At present, the standard arrangement of the air cleanup system responsible for emergency tritium recovery from room air is a catalytic oxidation bed with a heater followed by an adsorption bed with a cooler. One disadvantage of this arrangement is that trouble with the heater or the cooler could result in a loss of capacity to recover tritium. Another disadvantage of the catalyst-adsorption-bed arrangement is that tritiated water must be recovered with a high decontamination factor after dilution with a large amount of water vapor in the working atmosphere. The performance of a new arrangement for the air cleanup system, which consists of a precious metal catalyst bed preceded by an adsorption bed without heating equipment, is discussed. According to calculations, most of the tritium released to the room air is recovered in the catalyst bed through oxidation, adsorption, and isotope exchange reaction when the new arrangement is applied. The adsorption bed placed before the catalyst bed dehumidifies the process gas to such a degree that the oxidation reaction of tritium in the catalyst bed is not hindered by water vapor. 15 refs., 6 figs., 6 tabs

Effect of water temperature on survival of early-life stages of marbled flounder Pseudopleuronectes yokohamae in Tokyo Bay, Japan.

Science.gov (United States)

Lee, Jeong-Hoon; Kodama, Keita; Oyama, Masaaki; Shiraishi, Hiroaki; Horiguchi, Toshihiro

2017-07-01

We investigated factors that might have disturbed the stock recovery of marbled flounder in Tokyo Bay by focusing on the early life stages. Field surveys in Tokyo Bay from 2006 to 2011 revealed that mature adult biomass increased from 2006 to 2008 and decreased thereafter. Meanwhile, larval and juvenile densities were high in 2006 and 2008 but low in other years. Discrepancies in the yearly trends of these parameters suggest that mortality during life stages between spawning and early larval phases might have affected the abundance of the subsequent life stages. Monthly mean water temperature between January and February, in which hatching and pelagic larvae occur in the bay, was lower in 2006 (8.6 °C) and 2008 (9.6 °C) than was observed in other years (10.4-11.4 °C). Significant negative correlation between water temperature and larval density implies that mortality during pre- and post-larval stages would be higher in warmer winter years (>10 °C). To test this hypothesis, we examined the effects of water temperature on mortality and development in egg and larval stages under controlled laboratory conditions. Hatching rate was high in a water temperature range of 9.2-12.7 °C (66.6-82.5%), whereas it decreased in cooler (3.7% at 5.9 °C) or warmer (33.9% at 14.8 °C) conditions. Meanwhile, days from fertilization to hatching, size of larvae at hatching and survival rate of larvae after 18 d from hatching were monotonically and significantly decreased as water temperature was elevated. Combined evidence of the field and laboratory studies suggests that a warmer reproductive season (>10 °C) might induce mortalities of marbled flounder larvae in Tokyo Bay. Copyright © 2016 Elsevier Ltd. All rights reserved.

Water and steam sampling systems; Provtagningssystem foer vatten och aanga

Energy Technology Data Exchange (ETDEWEB)

Hellman, Mats

2009-10-15

The supervision of cycle chemistry can be divided into two parts, the sampling system and the chemical analysis. In modern steam generating plants most of the chemical analyses are carried out on-line. The detection limits of these analyzers are pushed downward to the ppt-range (parts per trillion), however the analyses are not more correct than the accuracy of the sampling system. A lot of attention has been put to the analyzers and the statistics to interpret the results but the sampling procedures has gained much less attention. This report aims to give guidance of the considerations to be made regarding sampling systems. Sampling is necessary since most analysis of interesting parameters cannot be carried out in- situ on-line in the steam cycle. Today's on-line instruments for pH, conductivity, silica etc. are designed to meet a water sample at a temperature of 10-30 deg C. This means that the sampling system has to extract a representative sample from the process, transport and cool it down to room temperature without changing the characteristics of the fluid. In the literature research work, standards and other reports can be found. Although giving similar recommendations in most aspects there are some discrepancies that may be confusing. This report covers all parts in the sampling system: Sample points and nozzles; Sample lines; Valves, regulating and on-off; Sample coolers; Temperature, pressure and flow rate control; Cooling water; and Water recovery. On-line analyzers connecting to the sampling system are not covered. This report aims to clarify what guidelines are most appropriate amongst the existing ones. The report should also give guidance to the design of the sampling system in order to achieve representative samples. In addition to this the report gives an overview of the fluid mechanics involved in sampling. The target group of this report is owners and operators of steam generators, vendors of power plant equipment, consultants working in

Water resources of Parowan Valley, Iron County, Utah

Science.gov (United States)

Marston, Thomas M.

2017-08-29

. Groundwater flows from the high-altitude recharge areas downward toward the basin-fill aquifer in Parowan Valley. Almost all groundwater discharge occurs as withdrawals from irrigation wells in the valley with a small amount of discharge from phreatophytic evapotranspiration. Subsurface groundwater discharge to Cedar Valley is likely minimal. Withdrawals from wells during 2013 were about 32,000 acre-ft. The estimated withdrawals from wells from 1994 to 2013 have ranged from 22,000 to 39,000 acre-ft per year. Declining water levels are an indication of the estimated average annual decrease in groundwater storage of 15,000 acre-ft from 1994 to 2013.Groundwater and surface-water samples were collected from 46 sites in Parowan Valley and Cedar Valley near the town of Enoch during June 2013. Groundwater samples from 34 wells were submitted for geochemical analysis. The total dissolved-solids concentration in water from these wells ranged from 142 to 886 milligrams per liter. Results of stable isotope analysis of oxygen and deuterium from groundwater and surface-water samples indicate that most of the groundwater in Parowan Valley and in Cedar Valley near Enoch is similar in isotopic composition to water from mountain streams, which reflects meteoric water recharged in high-altitude areas east of the valley. In addition, results of stable isotope analysis of a subset of samples from wells located near Little Salt Lake may indicate recharge of precipitation that occurred during cooler climatic conditions of the Pleistocene Epoch.

Air cooling of refrigerating loops: 'dry-hybrid' systems; Refroidissement par air des circuits frigorifiques: les systemes ''secs hybrides''

Energy Technology Data Exchange (ETDEWEB)

Becker, W. [Societe Jaggi-Gunter (Switzerland)

2003-02-01

Different type of cooling systems can be implemented on coldness production plants. The choice very often depends on the initial investment, but from a technical and economical point of view, this choice is not necessary the best solution. Thus, it can be useful to know the different existing systems and their exploitation costs with respect to the expected needs. A particular solution which uses a 'dry-hybrid' cooler is presented in this study: 1 - open-loop evaporative cooler; 2 - open-loop evaporative cooler with intermediate exchanger; 3 - close-loop evaporative cooler; 4 - dry-cooler; 5 - dry cooler with spraying in the air flow way; 6 - dry cooler with counterflow spraying; 7 - hybrid dry cooler; 8 - example of a realization in Germany: technical and economical value of the project, description of compared solutions and hypotheses, interpretation of results. (J.S.)

Near-shore distribution of Heaviside's ( Cephalorhynchus heavisidii ...

African Journals Online (AJOL)

Heaviside's dolphins were found in shallower, cooler water than dusky dolphins and were more likely to be seen during brighter phases of the moon (when nocturnal light conditions may influence the vertical migration patterns of prey) and in areas of high hake abundance. Near-shore fishing activity was higher in the ...

Tests of cooling water pumps at Dukovany nuclear power plant

International Nuclear Information System (INIS)

Travnicek, J.

1986-01-01

Tests were performed to examine the operating conditions of the 1600 BQDV cooling pumps of the main coolant circuit of unit 1 of the Dukovany nuclear power plant. For the pumps, the performance was tested in the permissible operating range, points were measured below this range and the guaranteed operating point was verified. Pump efficiency was calculated from the measured values. The discussion of the measurement of parameters has not yet been finished because the obtained values of the amount delivered and thus of the pump efficiency were not up to expectation in all detail. It was also found that for obtaining the guaranteed flow the pump impeller had to be opened to 5deg -5.5deg instead of the declared 3deg. Also tested were pump transients, including the start of the pump, its stop, the operation and failure of one of the two pumps. In these tests, pressures were also measured at the inlet and the outlet of the inner part of the TG 11 turbine condenser. It was shown that the time course and the pressure course of the processes were acceptable. In addition to these tests, pressure losses in the condenser and the cooling water flow through the feed pump electromotor cooler wre tested for the case of a failure of one of the two pumps. (E.S.)

Ecosystem maturation follows the warming of the Arctic fjords

OpenAIRE

Jan Marcin Węsławski; Friedrich Buchholz; Marta Głuchowska; Agata Weydmann

2017-01-01

Two fjords in West Spitsbergen (Hornsund 77°N and Kongsfjorden 79°N) differ with regard to their exposure towards increasingly warm Atlantic water inflow. Hornsund remains in many respects cooler than Kongsfjorden (on average 2°C SST in summer) and is less influenced by warmer and more saline Atlantic waters. Reported changes in the physical environment (temperature rise, freshwater inflow, salinity drop, turbidity, fast-ice reduction, coastal change) are discussed in the context of biologica...

Proceedings of the Gulf Stream Workshop Held at West Greenwich, Rhode Island on 23-26 April 1985,

Science.gov (United States)

1985-04-01

from the cooler (blue-to- green ) slope water to the warmer (yellow-to-red) waters of the Gulf Stream and Sargasso Sea. Further use. of satellite...baroclinic instability. In fact, Hogg (1985) has shown that these motions closely resemble those predicted by the Gill, Green and Simmons (1974...experiment in which observations in .., e form of 4x instead of Ay were provtied c"velocity" instea of "svrearmfunctaon"). The behavor of the error

Investigation of the effect of pressure increasing in condensing heat-exchanger

Science.gov (United States)

Murmanskii, I. B.; Aronson, K. E.; Brodov, Yu M.; Galperin, L. G.; Ryabchikov, A. Yu.; Brezgin, D. V.

2017-11-01

The effect of pressure increase was observed in steam condensation in the intermediate coolers of multistage steam ejector. Steam pressure increase for ejector cooler amounts up to 1.5 kPa in the first ejector stage, 5 kPa in the second and 7 kPa in the third one. Pressure ratios are equal to 2.0, 1.3 and 1.1 respectively. As a rule steam velocities at the cooler inlets do not exceed 40…100 m/s and are subsonic in all regimes. The report presents a computational model that describes the effect of pressure increase in the cooler. The steam entering the heat exchanger tears the drops from the condensate film flowing down vertical tubes. At the inlet of heat exchanger the steam flow capturing condensate droplets forms a steam-water mixture in which the sound velocity is significantly reduced. If the flow rate of steam-water mixture in heat exchanger is greater than the sound velocity, there occurs a pressure shock in the wet steam. On the basis of the equations of mass, momentum and energy conservation the authors derived the expressions for calculation of steam flow dryness degree before and after the shock. The model assumes that droplet velocity is close to the velocity of the steam phase (slipping is absent); drops do not come into thermal interaction with the steam phase; liquid phase specific volume compared to the volume of steam is neglected; pressure shock is calculated taking into account the gas-dynamic flow resistance of the tube bundle. It is also assumed that the temperature of steam after the shock is equal to the saturation temperature. The calculations have shown that the rise of steam pressure and temperature in the shock results in dryness degree increase. For calculated flow parameters the velocity value before the shock is greater than the sound velocity. Thus, on the basis of generally accepted physics knowledge the computational model has been formulated for the effect of steam pressure rise in the condensing heat exchanger.

Atmospheric Radiation Measurement Program facilities newsletter, February 2001.; TOPICAL

International Nuclear Information System (INIS)

Holdridge, D. J.

2001-01-01

This newsletter consists of the following: (1) ARM Science Team Meeting Scheduled-The 11th Annual ARM Science Team meeting is scheduled for March 19-23, 2001, in Atlanta, Georgia. Members of the science team will exchange research results achieved by using ARM data. The science team is composed of working groups that investigate four topics: instantaneous radiative flux, cloud parameterizations and modeling, cloud properties, and aerosols. The annual meeting brings together the science team's 150 members to discuss issues related to ARM and its research. The members represent universities, government laboratories and research facilities, and independent research companies. (2) Communications to Extended Facilities Upgraded-New communications equipment has been installed at all of the SGP extended facilities. Shelters were installed to house the new equipment used to transfer data from instruments via the Internet to the site data system at the central facility. This upgrade has improved data availability from the extended facilities to 100% and reduced telephone costs greatly. (3) SGP Goes ''Buggy''-Steve Sekelsky, a researcher from the University of Massachusetts, is planning to bring a 95-GHz radar to the SGP central facility for deployment in March-October 2001. The radar will help to identify signals due to insects flying in the air. The ARM millimeter cloud radar, which operates at 35 GHz, is sensitive to such insect interference. Testing will also be performed by using a second 35-GHz radar with a polarized radar beam, which can differentiate signals from insects versus cloud droplets. (4) Winter Fog-Fog can add to hazards already associated with winter weather. Common types of fog formation include advection, radiation, and steam. Advection fog: An advection fog is a dense fog that forms when a warm, moist air mass moves into an area with cooler ground below. For example, fog can form in winter when warmer, water-saturated air from the south (associated with

The Influence of the Silicon Component in the Paste for Processor Cooling

Directory of Open Access Journals (Sweden)

Antun Koren

2003-12-01

Full Text Available The development of computer coolers foreseen for the processors keeps step with the processors for PC platform. There are still working and development areas where one could find new technologies and the kinds of the alternative cooling which give better results that the existing classical methods. There are several kinds of alternative cooling, from cooling with the mixture of water and methanol to the usage of freon and liquid nitrogen as the cooling media. The purpose of this work is to point at some new alternative cooling methods and to compare them with the classical ones as well as to stress the problems in classical - mechanically treated cooler and additives of chemically prepared pastes for better heat conductivity from the core surface of the processor.

Last glacial-Holocene temperatures and hydrology of the Sea of Galilee and Hula Valley from clumped isotopes in Melanopsis shells

Science.gov (United States)

Zaarur, Shikma; Affek, Hagit P.; Stein, Mordechai

2016-04-01

The carbonate clumped isotope (Δ47) thermometer was applied to fresh water snails (Melanopsis spp.) grown in the waters of the Sea of Galilee and Hula Valley, in the north of Israel. Modern shells, grown at known temperatures agree with the Δ47-T calibration of Zaarur et al. (2013). Fossil Melanopsis shells from 2 locations, Gesher Bnot Ya'aqov (at the southern tip of the Hula Valley) and the Sea of Galilee provide a temperature record for the region during the time interval of the past 20 kyrs. Glacial temperatures are ∼5 °C cooler than mid-Holocene and ∼3 °C cooler than modern, similar to other records in the region. These Δ47-derived temperatures are combined with δ18O of the shell carbonate to calculate the oxygen isotopic composition of the habitat waters. Contrary to global trends and other regional records, reconstructed δ18Owater values increase from the late glacial through the Holocene. This reversed signal reflects a decrease in the relative contribution of snowmelt to the watershed post-LGM and a transition to a more rain dominated inflow. A fairly constant difference in δ18Owater values between the Hula Valley and Sea of Galilee waters, suggests that the hydrological relationship of the two water bodies had remained constant, with the temperature changes playing only a minor role in the extent of evaporation of the Sea of Galilee relative to the Hula.

Tactical versus space cryocoolers: a comparision

Science.gov (United States)

Arts, R.; Mullié, J.; Leenders, H.; de Jonge, G.; Benschop, T.

2017-05-01

In recent years, several space cryocooler developments have been performed in parallel at Thales Cryogenics. On one end of the spectrum are research programmes such as the ESA-funded 30-50 K system developed in cooperation with CEA and Absolut System and the LPT6510 cooler developed in cooperation with Absolut System. On the other end of the spectrum are commercial designs adapted for space applications, such as the LPT9310 commercial coolers delivered for JPL's ECOSTRESS instrument and the LSF9199/30 SADA-compatible cooler delivered for various space programmes at Sofradir. In this paper, an overview is presented of the latest developments regarding these coolers. Initial performance results of the 30-50K cooler are discussed, pending developments for the LPT6510 cooler are presented, and the synergies between COTS and space are reviewed, such as design principles from space coolers being applied to an upgraded variant of the COTS LPT9310, as well as design principles from COTS coolers being applied to the LPT6510 for improved manufacturability.

Hydrological information products for the Off-Project Water Program of the Klamath Basin Restoration Agreement

Science.gov (United States)

Snyder, Daniel T.; Risley, John C.; Haynes, Jonathan V.

2012-01-01

distribution of ET. The METRIC technique uses thermal infrared Landsat imagery to quantify actual evapotranspiration at a 30-meter resolution that can be related to individual irrigated fields. Because evaporation uses heat energy, ground surfaces with large ET rates are left cooler as a result of ET than ground surfaces that have less ET. As a consequence, irrigated fields appear in the Landsat images as cooler than nonirrigated fields. Products produced from this study include total seasonal and total monthly (April-October) actual evapotranspiration maps for 2004 (a dry year) and 2006 (a wet year). Maps showing indicators of natural subirrigation were also provided by this study. "Subirrigation" as used here is the evapotranspiration of shallow groundwater by plants with roots that penetrate to or near the water table. Subirrigation often occurs at locations where the water table is at or above the plant rooting depth. Natural consumptive use by plants diminishes the benefit of retiring water rights in subirrigated areas. Some agricultural production may be possible, however, on subirrigated lands for which water rights are retired. Because of the difficulty in precisely mapping and quantifying subirrigation, this study presents several sources of spatially mapped data that can be used as indicators of higher subirrigation probability. These include the floodplain boundaries defined by stream geomorphology, water-table depth defined in Natural Resources Conservation Service (NRCS) soil surveys, and soil rooting depth defined in NRCS soil surveys. The two water-rights mapping products created in the study were "points of diversion" (POD) and "place of use" (POU) for surface-water irrigation rights. To create these maps, all surface-water rights data, decrees, certificates, permits, and unadjudicated claims within the entire 1,900 square mile study area were aggregated into a common GIS geodatabase. Surface-water irrigation rights within a 5-mile buffer of the study area were

Seasonally-Active Water on Mars: Vapour, Ice, Adsorbate, and the Possibility of Liquid

Science.gov (United States)

Richardson, M. I.

2002-12-01

Seasonally-active water can be defined to include any water reservoir that communicates with other reservoirs on time scales of a year or shorter. It is the interaction of these water reservoirs, under the influence of varying solar radiation and in conjunction with surface and atmospheric temperatures, that determines the phase-stability field for water at the surface, and the distribution of water in various forms below, on, and above the surface. The atmosphere is the critical, dynamical link in this cycling system, and also (fortunately) one of the easiest to observe. Viking and Mars Global Surveyor observations paint a strongly asymmetric picture of the global seasonal water cycle, tied proximately to planetary eccentricity, and the existence of residual ice caps of different composition at the two poles. The northern summer experiences the largest water vapour columns, and is associated with sublimation from the northern residual water ice cap. The southern summer residual carbon dioxide ice cap is cold trap for water. Asymmetry in the water cycle is an unsolved problem. Possible solutions may involve the current timing of perihelion (the water cap resides at the pole experiencing the longer but cooler summer), the trapping of water ice in the northern hemisphere by tropical water ice clouds, and the bias in the annual-average, zonal-mean atmospheric circulation resulting from the zonal-mean difference in the elevation of the northern and southern hemispheres. Adsorbed and frozen water have proven harder to constrain. Recent Odyssey Gamma Ray Spectrometer results suggest substantial ground ice in the mid- and high-latitudes, but this water is likely below the seasonal skin depth for two reasons: the GRS results are best fit with such a model, and GCM models of the water cycle produce dramatically unrealistic atmospheric vapour distributions when such a very near surface, GRS-like distribution is initialized - ultimately removing the water to the northern and

The effect of increasing water temperatures on Schistosoma mansoni transmission and Biomphalaria pfeifferi population dynamics: an agent-based modelling study.

Directory of Open Access Journals (Sweden)

Nicky McCreesh

Full Text Available There is increasing interest in the control and elimination of schistosomiasis. Little is known, however, about the likely effects of increasing water-body temperatures on transmission.We have developed an agent-based model of the temperature-sensitive stages of the Schistosoma and intermediate host snail life-cycles, parameterised using data from S. mansoni and Biomphalaria pfeifferi laboratory and field-based observations. Infection risk is calculated as the number of cercariae in the model, adjusted for their probability of causing infection.The number of snails in the model is approximately constant between 15-31°C. Outside this range, snail numbers drop sharply, and the snail population cannot survive outside the range 14-32°C. Mean snail generation time decreases with increasing temperature from 176 days at 14°C to 46 days at 26°C. Human infection risk is highest between 16-18°C and 1pm and 6-10pm in calm water, and 20-25°C and 12-4pm in flowing water. Infection risk increases sharply when temperatures increase above the minimum necessary for sustained transmission.The model suggests that, in areas where S. mansoni is already endemic, warming of the water at transmission sites will have differential effects on both snails and parasites depending on abiotic properties of the water-body. Snail generation times will decrease in most areas, meaning that snail populations will recover faster from natural population reductions and from snail-control efforts. We suggest a link between the ecological properties of transmission sites and infection risk which could significantly affect the outcomes of interventions designed to alter water contact behaviour--proposing that such interventions are more likely to reduce infection levels at river locations than lakes, where infection risk remains high for longer. In cooler areas where snails are currently found, increasing temperatures may significantly increase infection risk, potentially leading

Infrared remote sensing for canopy temperature in paddy field and relationship between leaf temperature and leaf color

International Nuclear Information System (INIS)

Wakiyama, Y.

2002-01-01

Infrared remote sensing is used for crop monitoring, for example evaluation of water stress, detection of infected crops and estimation of transpiration and photosynthetic rates. This study was conducted to show another application of remote sensing information. The relationship between rice leaf temperature and chlorophyll content in the leaf blade was investigated by using thermography during the ripening period. The canopy of a rice community fertilized by top dressing was cooler than that not fertilized in a 1999 field experiment. In an experiment using thermocouples to measure leaf temperature, a rice leaf with high chlorophyll content was also cooler than that with a low chlorophyll content. Transpiration resistance and transpiration rate were measured with a porometer. Transpiration rate was higher with increasing chlorophyll content in the leaf blade. Stomatal aperture is related to chlorophyll content in the leaf blade. High degree of stomatal aperture is caused by high chlorophyll content in the leaf blade. As degree of stomatal aperture increases, transpiration rate increases. Therefore the rice leaf got cooler with increasing chlorophyll content in leaf blade. Paddy rice communities with different chlorophyll contents were provided with fertilization of different nitrogen levels on basal and top dressing in a 2000 field experiment. Canopy temperature of the rice community with high chlorophyll content was 0.85°C cooler than that of the rice community with low chlorophyll content. Results of this study revealed that infrared remote sensing could detect difference in chlorophyll contents in rice communities and could be used in fertilizer management in paddy fields. (author)

Design, fabrication and thermal characterization of a magnetocaloric microcooler

Energy Technology Data Exchange (ETDEWEB)

Kim, S.; Ghirlanda, S.; Adams, C.; Bethala, B.; Sambandam, S.N.; Bhansali, S. [BioMEMS and Microsystems Laboratory, Department of Electrical Engineering, University of South Florida, 4202 E. Fowler Ave., ENB118, Tampa, FL 33620, (United States)

2006-12-11

Magnetocaloric cooling is an alternative, high-efficiency cooling technology. In this paper, we present the design and fabrication of a micromachined magnetocaloric cooler and demonstrate its ability to work in a small magnetic field (<1.2 T) with a cooling test. The cooler was built by fabricating Si microfluidic channels, and it was integrated with a Gd{sub 5}(Si{sub 2}Ge{sub 2}) magnetocaloric refrigeration element. The magnetic properties of the Gd{sub 5}(Si{sub 2}Ge{sub 2}) material were characterized to calculate the magnetic entropy change at different ambient temperatures. Three different methods to integrate the channel layer and the magnetocaloric element were evaluated to test sealing and cooling performance. The cooling tests were performed by providing a magnetic field using an electromagnet. A test jig was constructed between the poles of an electromagnet to maintain a steady temperature during the test. Cooling tests were performed on the magnetocaloric element at ambient temperatures ranging from 258 to 280 K using a magnetic field of 1.2 T. Experimental results showed a maximum temperature change of 7 K on the magnetocaloric element alone at an ambient temperature of 258 K. Cooling tests of the fully integrated coolers were also performed. A solution of anti-freeze fluid (propylene glycol) and water was used as the coolant. The temperature of the working fluid decreased by 4.6 and 9 K for the glass and Si intermediate layers, respectively, confirming that the thermal conductivity of the materials is also an important factor in cooler performance. (Author)

Satellite tagging highlights the importance of productive Mozambican coastal waters to the ecology and conservation of whale sharks

Science.gov (United States)

Richardson, Anthony J.; Jaine, Fabrice R. A.; Bennett, Michael B.; Weeks, Scarla J.; Cliff, Geremy; Robinson, David P.; Reeve-Arnold, Katie E.; Pierce, Simon J.

2018-01-01

The whale shark Rhincodon typus is an endangered, highly migratory species with a wide, albeit patchy, distribution through tropical oceans. Ten aerial survey flights along the southern Mozambican coast, conducted between 2004–2008, documented a relatively high density of whale sharks along a 200 km stretch of the Inhambane Province, with a pronounced hotspot adjacent to Praia do Tofo. To examine the residency and movement of whale sharks in coastal areas around Praia do Tofo, where they may be more susceptible to gill net entanglement, we tagged 15 juveniles with SPOT5 satellite tags and tracked them for 2–88 days (mean = 27 days) as they dispersed from this area. Sharks travelled between 10 and 2,737 km (mean = 738 km) at a mean horizontal speed of 28 ± 17.1 SD km day−1. While several individuals left shelf waters and travelled across international boundaries, most sharks stayed in Mozambican coastal waters over the tracking period. We tested for whale shark habitat preferences, using sea surface temperature, chlorophyll-a concentration and water depth as variables, by computing 100 random model tracks for each real shark based on their empirical movement characteristics. Whale sharks spent significantly more time in cooler, shallower water with higher chlorophyll-a concentrations than model sharks, suggesting that feeding in productive coastal waters is an important driver of their movements. To investigate what this coastal habitat choice means for their conservation in Mozambique, we mapped gill nets during two dedicated aerial surveys along the Inhambane coast and counted gill nets in 1,323 boat-based surveys near Praia do Tofo. Our results show that, while whale sharks are capable of long-distance oceanic movements, they can spend a disproportionate amount of time in specific areas, such as along the southern Mozambique coast. The increasing use of drifting gill nets in this coastal hotspot for whale sharks is likely to be a threat to regional

Late Glacial temperature and precipitation changes in the lowland Neotropics by tandem measurement of δ 18O in biogenic carbonate and gypsum hydration water

Science.gov (United States)

Hodell, David A.; Turchyn, Alexandra V.; Wiseman, Camilla J.; Escobar, Jaime; Curtis, Jason H.; Brenner, Mark; Gilli, Adrian; Mueller, Andreas D.; Anselmetti, Flavio; Ariztegui, Daniel; Brown, Erik T.

2012-01-01

We applied a new method to reconstruct paleotemperature in the tropics during the last deglaciation by measuring oxygen isotopes of co-occurring gypsum hydration water and biogenic carbonate in sediment cores from two lakes on the Yucatan Peninsula. Oxygen and hydrogen isotope values of interstitial and gypsum hydration water indicate that the crystallization water preserves the isotopic signal of the lake water, and has not undergone post-depositional isotopic exchange with sediment pore water. The estimated lake water δ18O is combined with carbonate δ18O to calculate paleotemperature. Three paired measurements of 1200-yr-old gypsum and gastropod aragonite from Lake Chichancanab, Mexico, yielded a mean temperature of 26 °C (range 23-29.5 °C), which is consistent with the mean and range of mean annual temperatures (MAT) in the region today. Paired measurements of ostracods, gastropods, and gypsum hydration water samples were measured in cores from Lake Petén Itzá, Guatemala, spanning the Late Glacial and early Holocene period (18.5-10.4 ka). The lowest recorded temperatures occurred at the start of Heinrich Stadial (HS) 1 at 18.5 ka. Inferred temperatures from benthic ostracods ranged from 16 to 20 °C during HS 1, which is 6-10 °C cooler than MAT in the region today, whereas temperatures derived from shallow-water gastropods were generally warmer (20-25 °C), reflecting epilimnetic temperatures. The derived temperatures support previous findings of greater tropical cooling on land in Central America during the Late Glacial than indicated by nearby marine records. Temperature increased in two steps during the last deglaciation. The first occurred during the Bolling-Allerod (B-A; from 14.7 to 13 ka) when temperature rose to 20-24 °C towards the end of this period. The second step occurred at 10.4 ka near the beginning of the Holocene when ostracod-inferred temperature rose to 26 °C, reflecting modern hypolimnetic temperature set during winter, whereas

Value impact analysis of Generic Issue 143, Availability of Heating, Ventilation, Air Conditioning (HVAC) and Chilled Water Systems

Energy Technology Data Exchange (ETDEWEB)

Daling, P.M.; Marler, J.E.; Vo, T.V.; Phan, H.; Friley, J.R. [Pacific Northwest Lab., Richland, WA (United States)

1993-11-01

This study evaluates the values (benefits) and impacts (costs) associated with potential resolutions to Generic Issue 143, ``Availability of HVAC and Chilled Water Systems.`` The study identifies vulnerabilities related to failures of HVAC, chilled water, and room cooling systems; develops estimates of room heatup rates and safety-related equipment vulnerabilities following losses of HVAC/room cooler systems; develops estimates of the core damage frequencies and public risks associated with failures of these systems; develops three proposed resolution strategies to this generic issue; and performs a value/impact analysis of the proposed resolutions. Existing probabilistic risk assessments for four representative plants, including one plant from each vendor, form the basis for the core damage frequency and public risk calculations. Both internal and external events were considered. It was concluded that all three proposed resolution strategies exceed the $1,000/person-rem cost-effectiveness ratio. Additional evaluations were performed to develop ``generic`` insights on potential design-related and configuration-related vulnerabilities and potential high-frequency ({approximately}1E-04/RY) accident sequences that involve failures of HVAC/room cooling functions. It was concluded that, although high-frequency accident sequences may exist at some plants, these high-frequency sequences are plant-specific in nature or have been resolved through hardware and/or operational changes. The plant-specific Individual Plant Examinations are an effective vehicle for identification and resolution of these plant-specific anomalies and hardware configurations.

Value impact analysis of Generic Issue 143, Availability of Heating, Ventilation, Air Conditioning (HVAC) and Chilled Water Systems

International Nuclear Information System (INIS)

Daling, P.M.; Marler, J.E.; Vo, T.V.; Phan, H.; Friley, J.R.

1993-11-01

This study evaluates the values (benefits) and impacts (costs) associated with potential resolutions to Generic Issue 143, ''Availability of HVAC and Chilled Water Systems.'' The study identifies vulnerabilities related to failures of HVAC, chilled water, and room cooling systems; develops estimates of room heatup rates and safety-related equipment vulnerabilities following losses of HVAC/room cooler systems; develops estimates of the core damage frequencies and public risks associated with failures of these systems; develops three proposed resolution strategies to this generic issue; and performs a value/impact analysis of the proposed resolutions. Existing probabilistic risk assessments for four representative plants, including one plant from each vendor, form the basis for the core damage frequency and public risk calculations. Both internal and external events were considered. It was concluded that all three proposed resolution strategies exceed the $1,000/person-rem cost-effectiveness ratio. Additional evaluations were performed to develop ''generic'' insights on potential design-related and configuration-related vulnerabilities and potential high-frequency (∼1E-04/RY) accident sequences that involve failures of HVAC/room cooling functions. It was concluded that, although high-frequency accident sequences may exist at some plants, these high-frequency sequences are plant-specific in nature or have been resolved through hardware and/or operational changes. The plant-specific Individual Plant Examinations are an effective vehicle for identification and resolution of these plant-specific anomalies and hardware configurations

What do computer worlds tell us about changes to rain and falling ice-water in the state where this meeting is usually held?

Science.gov (United States)

Langenbrunner, B.

2017-12-01

To learn how the world will change because of human-caused warming, we use computer-made worlds that couple land, water, and air to study their responses to the causes of warming over many years. For changes to rain and falling ice-water, these computer worlds are great at answering questions about very large places, like big areas of land or water, but they are not as good when thinking about more focused areas, like cities or states. This is especially true in the state where this meeting happens most years; will it be wetter or drier by the year 2100, and by how much? I will talk about the work being done to learn why these computer worlds do not always agree, as well as the work that finds changes on which they do agree. One big reason they don't agree is because these computer worlds arrive at different guesses on how winds will shift high up in the air in cooler months. These winds will push rain and falling ice-water to different places up and down the state over time, making it hard to know what we can expect, though our best guess is that it will be ever-so-slightly wetter. Computer worlds do agree, however, on two important things across most of the state: that the very largest bursts of rain will happen more often as the world warms, and that more often, very wet years will follow very dry years immediately before them. Taken together, these changes are important to the those in the state who plan for up-coming water needs. Knowing how normal rain and ice-water will change is part of the story, but perhaps more important is understanding how the very biggest showers are shifting, which will help the state plan for and handle these more sudden (and serious) bursts of water.

Dipole vortices in the Great Australian Bight

DEFF Research Database (Denmark)

Cresswell, George R.; Lund-Hansen, Lars C.; Nielsen, Morten Holtegaard

2015-01-01

Shipboard measurements from late 2006 made by the Danish Galathea 3 Expedition and satellite sea surface temperature images revealed a chain of cool and warm mushroom' dipole vortices that mixed warm, salty, oxygen-poor waters on and near the continental shelf of the Great Australian Bight (GAB...... denser than the cooler offshore waters. The field of dipoles evolved and distorted, but appeared to drift westwards at 5km day-1 over two weeks, and one new mushroom carried GAB water southwards at 7km day(-1). Other features encountered between Cape Leeuwin and Tasmania included the Leeuwin Current...

Mono screw-type compressor with R410-A. The StarGate{sup TM} of McQuay; Monoschroefcompressor met R410-A. De StarGate{sup T}M van McQuay

Energy Technology Data Exchange (ETDEWEB)

Vermeule, P. [McQuay Stulz Groep, Amstelveen (Netherlands)

1997-03-01

R410-A is mentioned in many articles as a refrigerant for the future. However, a specially designed compressor is required which can resist the higher pressure as a result of applying that coolant. A description is given of the title compressor which is said to be appropriate for R410-A, applied in water-cooled fluid coolers. 2 ills., 3 tabs.

Thermal analysis of a direct evaporative cooling system enhancement with desiccant dehumidification for vehicular air conditioning

International Nuclear Information System (INIS)

Alahmer, Ali

2016-01-01

Highlights: • Thermal analysis was conducted to design a desiccant evaporative cooling system for vehicular air conditioning. • EC is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter. • Drawbacks of evaporative cooler of increased weight and reduced COP. • A rotary desiccant dehumidifier with generation was combined with evaporative cooling to be more efficient. - Abstract: This manuscript analyzes the sub-systems of evaporative cooler (EC) combined with desiccant dehumidification and regeneration for automotive air conditioning purpose. The thermodynamic and psychometric analysis was conducted to design all evaporative cooling system components in terms of desiccant selection, regeneration process, compact heat exchanger and evaporative cooler. Moreover, the effect of the desiccant, heat exchanger and evaporative performances on the mass flow rate and water sprayed required for evaporative cooling system was investigated. The results show that the theoretical evaporative cooling design will achieve two main objectives: lower fuel consumption and less environmental pollutants. However, it has the two drawbacks in terms of increased weight and reduces the coefficient of performance (COP). The main remark is that evaporating cooling system is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter.

Rapid fluctuations in flow and water-column properties in Asan Bay, Guam: implications for selective resilience of coral reefs in warming seas

Science.gov (United States)

Storlazzi, C. D.; Field, M. E.; Cheriton, O. M.; Presto, M. K.; Logan, J. B.

2013-12-01

Hydrodynamics and water-column properties were investigated off west-central Guam from July 2007 through January 2008. Rapid fluctuations, on time scales of 10s of min, in currents, temperature, salinity, and acoustic backscatter were observed to occur on sub-diurnal frequencies along more than 2 km of the fore reef but not at the reef crest. During periods characterized by higher sea-surface temperatures (SSTs), weaker wind forcing, smaller ocean surface waves, and greater thermal stratification, rapid decreases in temperature and concurrent rapid increases in salinity and acoustic backscatter coincided with onshore-directed near-bed currents and offshore-directed near-surface currents. During the study, these cool-water events, on average, lasted 2.3 h and decreased the water temperature 0.57 °C, increased the salinity 0.25 PSU, and were two orders of magnitude more prevalent during the summer season than the winter. During the summer season when the average satellite-derived SST anomaly was +0.63 °C, these cooling events, on average, lowered the temperature 1.14 °C along the fore reef but only 0.11 °C along the reef crest. The rapid shifts appear to be the result of internal tidal bores pumping cooler, more saline, higher-backscatter oceanic water from depths >50 m over cross-shore distances of 100 s of m into the warmer, less saline waters at depths of 20 m and shallower. Such internal bores appear to have the potential to buffer shallow coral reefs from predicted increases in SSTs by bringing cool, offshore water to shallow coral environments. These cooling internal bores may also provide additional benefits to offset stress such as supplying food to thermally stressed corals, reducing stress due to ultraviolet radiation and/or low salinity, and delivering coral larvae from deeper reefs not impacted by surface thermal stress. Thus, the presence of internal bores might be an important factor locally in the resilience of select coral reefs facing increased

Rapid fluctuations in flow and water-column properties in Asan Bay, Guam: implications for selective resilience of coral reefs in warming seas

Science.gov (United States)

Storlazzi, Curt D.; Field, Michael E.; Cheriton, Olivia M.; Presto, M.K.; Logan, J.B.

2013-01-01

Hydrodynamics and water-column properties were investigated off west-central Guam from July 2007 through January 2008. Rapid fluctuations, on time scales of 10s of min, in currents, temperature, salinity, and acoustic backscatter were observed to occur on sub-diurnal frequencies along more than 2 km of the fore reef but not at the reef crest. During periods characterized by higher sea-surface temperatures (SSTs), weaker wind forcing, smaller ocean surface waves, and greater thermal stratification, rapid decreases in temperature and concurrent rapid increases in salinity and acoustic backscatter coincided with onshore-directed near-bed currents and offshore-directed near-surface currents. During the study, these cool-water events, on average, lasted 2.3 h and decreased the water temperature 0.57 °C, increased the salinity 0.25 PSU, and were two orders of magnitude more prevalent during the summer season than the winter. During the summer season when the average satellite-derived SST anomaly was +0.63 °C, these cooling events, on average, lowered the temperature 1.14 °C along the fore reef but only 0.11 °C along the reef crest. The rapid shifts appear to be the result of internal tidal bores pumping cooler, more saline, higher-backscatter oceanic water from depths >50 m over cross-shore distances of 100 s of m into the warmer, less saline waters at depths of 20 m and shallower. Such internal bores appear to have the potential to buffer shallow coral reefs from predicted increases in SSTs by bringing cool, offshore water to shallow coral environments. These cooling internal bores may also provide additional benefits to offset stress such as supplying food to thermally stressed corals, reducing stress due to ultraviolet radiation and/or low salinity, and delivering coral larvae from deeper reefs not impacted by surface thermal stress. Thus, the presence of internal bores might be an important factor locally in the resilience of select coral reefs facing increased

Split-Stirling Cryogenic Refrigerators For Detector Cooling

Science.gov (United States)

Lehrfeld, Daniel

1983-08-01

Unfortunately, for user and manufacturer both, the closed-cycle cryogenic cooler to date has deserved its reputation as the "weak-link" in IR systems. When the cooler requires service at intervals of a few hundred hours at best, the quality of the system it serves is unfairly diminished. This paper addresses technological advances in the art of Stirling-cycle coolers which will increasingly cause that image of military cryocoolers to change for the better. A family of split-cycle coolers designed for long MTBF and in the final stages of development is the focus of the discussion. Their technological evolution, from multi-year-MTBF satellite system Stirling coolers developed in the U.S., and the UA 7011 cooler (tne first all-linear, military, production cooler) developed in Holland, is explained. Three new machines are discussed. Both 1/4 watt and 1 watt (nominal capacity) at 80°K linear-resonant, free-dispLacer Stirling coolers designed for thousands of hours of service-free operation are examined. The third machine is an advanced 1/4 watt at 80°K Stirling cooler incorporating the same component improvements in its free-displacer while utilizing a crankshaft-driven compressor. All three are designed to be compatible with standard U.S. 60 element and 120/180 element detector/dewars. The technologies of linear-resonant compressor and free-displacer expanders as embodied in these machines is discussed in sufficient detail that the reasons for their superior performance will he clear.

Air liquide's space pulse tube cryocooler systems

Science.gov (United States)

Trollier, T.; Tanchon, J.; Buquet, J.; Ravex, A.

2017-11-01

Thanks to important development efforts completed with ESA funding, Air Liquide Advanced Technology Division (AL/DTA), is now in position to propose two Pulse Tube cooler systems in the 40-80K temperature range for coming Earth Observation missions such as Meteosat Third Generation (MTG), SIFTI, etc… The Miniature Pulse Tube Cooler (MPTC) is lifting up to 2.47W@80K with 50W compressor input power and 10°C rejection temperature. The weight is 2.8 kg. The Large Pulse Tube Cooler (LPTC) is providing 2.3W@50K for 160W input power and 10°C rejection temperature. This product is weighing 5.1 kg. The two pulse tube coolers thermo-mechanical units are qualified against environmental constraints as per ECSS-E-30. They are both using dual opposed pistons flexure bearing compressor with moving magnet linear motors in order to ensure very high lifetime. The associated Cooler Drive Electronics is also an important aspect specifically regarding the active control of the cooler thermo-mechanical unit during the launch phase and the active reduction of the vibrations induced by the compressor (partly supported by the French Agency CNES). This paper details the presentation of the two Pulse Tube Coolers together with the Cooler Drive Electronics aspects.

Leakage detection system in nuclear reactor container

International Nuclear Information System (INIS)

Kurosawa, Masahiko.

1993-01-01

The present invention comprises an injection means for adding radioactive materials to coolants in a container cooler, a gamma ray amplitude analyzer connected to coolant pipelines and a means for recording/transferring the data of the result of the measurement, a gamma ray amplitude analyzer connected to a drain water sump and a means for recording/transferring the data of the result of the measurement, a gamma ray amplitude analyzer connected to various kinds of pipelines and a means for recording/transferring the data of the result of the measurement, and a data processing means for comparing and analyzing the measured data of each of the gamma ray amplitude analyzers inputted from each of date recording/transferring means. The gamma ray amplitude analysis for each of the pipelines and drain water sump are conducted at an appropriate frequency, and the measured data are compared and analyzed, to improve the detection accuracy for a trace amount of leakage from each of the pressure pipelines and the container cooler coolant pipelines, thereby enabling to specify the pipeline having leakage. Maintenance efficiency is improved, and severe rupture accident in each of pressure pipelines is prevented previously. (N.H.)

Clinical pathology reference intervals for an in-water population of juvenile loggerhead sea turtles (Caretta caretta) in Core Sound, North Carolina, USA.

Science.gov (United States)

Kelly, Terra R; McNeill, Joanne Braun; Avens, Larisa; Hall, April Goodman; Goshe, Lisa R; Hohn, Aleta A; Godfrey, Matthew H; Mihnovets, A Nicole; Cluse, Wendy M; Harms, Craig A

2015-01-01

The loggerhead sea turtle (Caretta caretta) is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as "threatened" on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing rehabilitation.

Clinical pathology reference intervals for an in-water population of juvenile loggerhead sea turtles (Caretta caretta in Core Sound, North Carolina, USA.

Directory of Open Access Journals (Sweden)

Terra R Kelly

Full Text Available The loggerhead sea turtle (Caretta caretta is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as "threatened" on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing

Stream-Groundwater Interaction Buffers Seasonal Changes in Urban Stream Water Quality

Science.gov (United States)

Ledford, S. H.; Lautz, L. K.

2013-12-01

Urban streams in the northeastern United States have large road salt inputs during winter, increased nonpoint sources of inorganic nitrogen, and decreased short-term and permanent storage of nutrients. Meadowbrook Creek, a first order stream in Syracuse, New York, flows along a negative urbanization gradient, from a channelized and armored stream running through the middle of a roadway to a pool-riffle stream meandering through a broad, vegetated floodplain with a riparian aquifer. In this study we investigated how reconnection to groundwater and introduction of riparian vegetation impacted surface water chemistry by making bi-weekly longitudinal surveys of stream water chemistry in the creek from May 2012 until June 2013. Chloride concentrations in the upstream, urban reach of Meadowbrook Creek were strongly influenced by discharge of road salt to the creek during snow melt events in winter and by the chemistry of water draining an upstream retention basin in summer. Chloride concentrations ranged from 161.2 mg/L in August to 2172 mg/L in February. Chloride concentrations in the downstream, 'connected' reach had less temporal variation, ranging from 252.0 mg/L in August to 1049 mg/L in January, and were buffered by groundwater discharge, as the groundwater chloride concentrations during the sampling period ranged from 84.0 to 655.4 mg/L. Groundwater discharge resulted in higher chloride concentrations in summer and lower concentrations in winter in the connected reach relative to the urban reach, minimizing annual variation. In summer, there was little-to-no nitrate in the urban reach due to a combination of limited sources and high primary productivity. In contrast, during the summer, nitrate concentrations reached over 1 mg N/L in the connected reach due to the presence of riparian vegetation and lower nitrate uptake due to cooler temperatures and shading. During the winter, when temperatures fell below freezing, nitrate concentrations in the urban reach

Bull trout (Salvelinus confluentus) movement in relation to water temperature, season, and habitat features in Arrowrock Reservoir, Idaho, 2012

Science.gov (United States)

Maret, Terry R.; Schultz, Justin E.

2013-01-01

detected in early June, suggesting that fish used little, if any, summertime habitat within the reservoir. Water-quality profile measurements indicated that temperature could limit bull trout use of the reservoir during warm, summer months that coincide with decreased water volume. Thermal refuge during this study appeared to be limited based on scarcity of water that was 15°C and cooler. From the first week of August through the latter part of September, little if any suitable habitat remained for bull trout, with most temperatures exceeding 15°C at all locations where water quality profiles were measured.

Can Cooler Heads Prevail?

Science.gov (United States)

Rice, A. R.

2015-12-01

The significant correlation between dropping temperatures throughout the Pliocene and the concomitant explosive expansion of the Hominid brain has led a number of workers to postulate climate change drove human evolution. Our brain (that of Homo sapiens), comprises 1-2 percent of our body weight but consumes 20 -25 percent of the body's caloric intake. We are "hotheads". Brains are extremely sensitive to overheating but we are endowed with unparalleled thermal regulation, much of it given over to protecting the Central Nervous System (CNS). Will there be reversed trends with global warming? The human brain has been shrinking since the end of the Ice Ages, losing about 150cc over the past 10,000 years. Polar bear skulls have been downsizing as well. Almost all mass extinctions or evolutionary upheavals are attributed to global warming: e.g. the Permian/Triassic (P/T) event, i.e., "The Great Dying", 250 million years ago (~90% of all life forms wiped out); the Paleocene/ Eocene Thermal Maximum (PETM) 55 million years ago. They may be analogs for what might await us. Large creatures, whose body size inhibits cooling, melted away during the PETM. Horses, initially the size of dogs then, reduced to the size of cats. An unanticipated hazard for humans that may attend extreme global warming is dumbing down or needing to retreat to the Poles as did those creatures that survived the P/T event (some references: http://johnhawks.net/research/hawks-2011-brain-size-selection-holocene; Kandel, E. et al Principles of Neural Science 4th ed. New York (US): McGraw-Hill, 2000; Selective Brain Cooling in Early Hominids:phylogenetic and evolutionary implications, Reeser, H., reeser@flmnh.ufl.edu; How the body controls brain temperature; the temperature shielding effect of cerebral blood flow, Mingming Z. et al. J Appl Physiol. 2006 November; 101(5): 1481-1488; news.nationalgeographic.com/ news/2014/03/140327-climate-change-shrinks-salamanders-global-warming-science/; Heat illness and heat stroke, www.ozemedicine.com/wiki/doku.php?id=heat illness 7/3/2010)

Detailed Theoretical Characterization of a Transcritical CO2 Direct Expansion Ground Source Heat Pump Water Heater

Directory of Open Access Journals (Sweden)

Parham Eslami-Nejad

2018-02-01

Full Text Available A new avenue in modern heat pump technology is related to the use of natural refrigerants such as carbon dioxide (CO2. The use of CO2 in direct expansion ground source heat pumps (DX-GSHP has also gained significant interest as it offers opportunities for cost reduction of the ground loop, albeit some challenges remain in their development, design and use. To address these challenges and to characterize CO2-DX-GSHP performance for water heating applications, a detailed theoretical model and a fully-instrumented test apparatus was developed and built at CanmetENERGY Research Laboratory. The theoretical model was validated against a set of experimental results and adopted to investigate the performance of the system over a wide operating range. Validation results showed that the model predicts the experimental results within the measurement uncertainty. A detailed system performance analysis was also performed using the theoretical model to understand the system behavior and explore the actions required for performance improvement in future installations. The results of the analysis showed that improper design and control of some components, such as the gas cooler and ground heat exchanger can degrade the system performance by up to 25%, and the heat pump heating capacity by 7.5%.

Coastal circulation and water-column properties in the National Park of American Samoa, February–July 2015

Science.gov (United States)

Storlazzi, Curt; Cheriton, Olivia; Rosenberger, Kurt; Logan, Joshua; Clark, Timothy B.

2017-06-06

saline, relatively less optically clear, and more stratified. When winds shifted to a more consistent trade wind pattern in the austral fall, the waters cooled and became less stratified because of decreased insolation. There are consistent spatial patterns in water column characteristics—Waters were warmer and less saline near the surface and closer to shore, especially in embayments, which tended to be more turbid, less clear, and characterized by higher chlorophyll than waters offshore. Water residence times were shorter farther offshore and longer closer to shore and in embayments, but varied spatially because of different forcing. Warmer, lower salinity, higher chlorophyll, and more turbid waters in embayments tend to reside in those locations for much greater durations, resulting in greater exposure of embayment ecosystems to those waters. This is in contrast with waters farther offshore, where the combination of shorter residence times and cooler, higher salinity water results in less exposure to land runoff. Understanding coastal circulation patterns and water-column properties in NPSA’s waters along north-central Tutuila may help to better understand how meteorological and oceanographic processes, at the regional and local scale, affect coral reef health and sustainability in this region.

Experimental study of the causes for the dispersion of the Leidenfrost temperature

International Nuclear Information System (INIS)

Zach, O.

1976-12-01

This paper studies the effects of various external disturbances on the collapse of a steam film forming after hot copper spheres are immersed in water. The steam film can already be destroyed at high sphere temperatures by influences of the sphere's surface (geometrical disturbances, oxidation) and by influences on the boundary layer ( afflux of cooler water, vibrations of the boundary surface). There is therefore only a lower limit for the Leidenfrost temperature where the steam film becomes unstable alone by the effect of the so-called unintended disturbances which are always existing. (orig.) [de

Seed germination of Stenocereus thurberi (Cactaceae) under different solar irradiation levels

International Nuclear Information System (INIS)

Nolasco, H.; Vega-Villasante, F.; Diaz-Rondero, A.

1997-01-01

Germination of Stenocereus thurberi seeds was evaluated under different conditions of solar irradiation and humidity. Seed germination increased under higher humidity and low solar irradiation which provided cooler temperatures and higher water availability. Seedlings were also greener and more turgid under these conditions. Increased solar irradiation reduced seed germination and decreased seedling size and water content. The results of this study support the importance of natural shelter systems in the arid zones in providing better conditions for S. thurberi seeds germination and seedling establishment, particularly in the desert of Baja California. (author)

A passive decay-heat removal system for an ABWR based on air cooling

Energy Technology Data Exchange (ETDEWEB)

Mochizuki, Hiroyasu, E-mail: mochizki@u-fukui.ac.jp [Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan); Yano, Takahiro [School of Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan)

2017-01-15

Highlights: • A passive decay heat removal system for an ABWR is discussed using combined system of the reactor and an air cooler. • Effect of number of pass of the finned heat transfer tubes on heat removal is investigated. • The decay heat can be removed by air coolers with natural convection. • Two types of air cooler are evaluated, i.e., steam condensing and water cooling types. • Measures how to improve the heat removal rate and to make compact air cooler are discussed. - Abstract: This paper describes the capability of an air cooling system (ACS) operated under natural convection conditions to remove decay heat from the core of an Advanced Boiling Water Reactor (ABWR). The motivation of the present research is the Fukushima Severe Accident (SA). The plant suffered damages due to the tsunami and entered a state of Station Blackout (SBO) during which seawater cooling was not available. To prevent this kind of situation, we proposed a passive decay heat removal system (DHRS) in the previous study. The plant behavior during the SBO was calculated using the system code NETFLOW++ assuming an ABWR with the ACS. However, decay heat removal under an air natural convection was difficult. In the present study, a countermeasure to increase heat removal rate is proposed and plant transients with the ACS are calculated under natural convection conditions. The key issue is decreasing pressure drop over the tube banks in order to increase air flow rate. The results of the calculations indicate that the decay heat can be removed by the air natural convection after safety relief valves are actuated many times during a day. Duct height and heat transfer tube arrangement of the AC are discussed in order to design a compact and efficient AC for the natural convection mode. As a result, a 4-pass heat transfer tubes with 2-row staggered arrangement is the candidate of the AC for the DHRS under the air natural convection conditions. The heat removal rate is re-evaluated as

Restoration to serviceability of Bruce 'A' heat transfer equipment

International Nuclear Information System (INIS)

Gammage, D.; Machowski, C.; McGillivray, R.; Durance, D.; Kazimer, D.; Werner, K.

2009-01-01

Bruce Units 1 to 4 were shut down during the 1990s by the former Ontario Hydro, due in part to a long list of system and equipment deficiencies and concerns, including steam generator tube degradation as a consequence of the then-existing steam generator secondary side water chemistry conditions. Upon its creation in 2001, and following a program of condition assessment, Bruce Power was able to determine that Units 3 and 4 could return to service; but that Units 1 and 2 would require refurbishment. That Refurbishment Program, which is currently well advanced, included the re-assessment of the condition of equipment throughout the plant including the heat transfer equipment; and determination item-by-item as to what inspection, cleaning, repair, or even replacement would be required to put the equipment into a condition where it could be expected to operate reliably for the additional 30 years expected from the plant. Clearly the objective is to suitably restore the equipment to serviceability without doing more refurbishment work than is warranted - without replacing equipment except where absolutely necessary. The first task in such a program is determination of its scope - i.e. a listing of all heat exchangers. That list included everything from the steam generators (which required replacement, now completed), to much smaller heat exchangers in the heavy water upgrader systems (which were found to be in very good overall condition). There is also a very large number of other so-called 'balance-of-plant' heat exchangers; these include the maintenance coolers, moderator heat exchangers, shutdown coolers and a whole raft of smaller coolers - many of which are cooled directly by lake water with its potential for bio-fouling and 'BIC' (Biologically Induced Corrosion). This paper focuses primarily on the engineering assessment, inspection, repair and general refurbishment of the balance-of-plant heat exchangers. As will be discussed in the paper, the assessment of the

Copper and nickel alloys and titanium for seawater applications

International Nuclear Information System (INIS)

Richter, H.

1977-01-01

Copper and nickel alloys and titanium have been successfully used for heat exchangers on ships, in power plants and for chemical apparatus and piping systems because of their resistance against corrosion in sea water. Aluminium brass and copper nickel alloys, the standard materials for condensers and coolers, however, may be attacked, the corrosion depending on water quality, water velocity, and structural conditions. The mechanisms of corrosion are discussed. Under severe conditions the use of titanium may be indicated. The use of nickel base alloys is advantageous at elevated temperatures, e.g. for chemical reactions and for evaporation processes. Examples are given for application and for prevention of corrosion. (orig.) [de

The preparation of computer-supported methods for the analysis of radiation situation at particle accelerators and their exemplary application to the cooler synchrotron COSY

International Nuclear Information System (INIS)

Moll, J.

1991-01-01

In this thesis the applicability of modern particle transport programs for the radiation protection of the new cooler synchrotron COSY has been investigated. Monte Carlo codes as the program system HERMES offer a large flexibility in geometry simulation and a wide spread applicability up to the GeV energy region because of its implemented physical models. These codes are very suitable for detailed analysis of radiation sources within the accelerator and for dose rate estimations behind radiation shields. Detailed calculations of double differentional flux spectra and surface dose rate distributions at a cylindrical standard target for different materials (iron, copper and lead) were done for 2.5GeV protons incident. In case of deep penetration problems it turns out, that the CPU-time requirement of the Monte Carlo codes increases rapidely. Therefore the Monte Carlo codes were coupled with a one-dimentional S n transport code to treat deep penetration problems in a reasonable computer CPU-time. For this purpose a new high energy neutron-γ transport library was evaluated taking into account the upper energy limit of COSY with 2.8GeV. The needed cross sections have been calculated by using the physical models of one of the HERMES-codes. Several Fortran-routines were developed to get an automatically procedure, which is used to evaluate the results and determine Legendre polynominals of order P3, which had to be inserted as coefficients into the library. The coupling procedure between the programs has been automated by means of several Fortran-routines, which does transformation, normalisation and formatting of the flux-data. (orig./HST) [de

Multiple stressors in agricultural streams: a mesocosm study of interactions among raised water temperature, sediment addition and nutrient enrichment.

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Jeremy J Piggott

strips, both in reducing sediment input and in maintaining cooler water temperatures.

Ecological studies of neritic phytoplankton of Southern California: seasonal variations, associations, and responses to temperature elevations

International Nuclear Information System (INIS)

Briand, F.J.P.

1974-01-01

The first part of this study investigates the seasonal variations and associations of the nearshore phytoplankton communities at Seal Beach, Orange County, California. A total of 90 species was recorded in samples taken weekly from June 1972 to May 1973. On a yearly basis, the two dominant algal groups were diatoms (46 species) and dinoflagellates (36 species), accounting respectively for 64.1 percent and 30.4 percent of the total cell number, and for 20.2 percent and 79.2 percent of the total cell volume. The species diversity index (H') remained relatively stable during the year, showing no distinct seasonal pattern. The major group, composed mainly of dinoflagellates, was correlated with warm water conditions at Seal Beach. At this location, two electric power plants use sea-water for cooling purposes at the rate of six million l/min, which subjects the planktonic organisms entrained in the condenser systems to appreciable temperature increases. This problem is general in southern California, where 14 coastal power plants draw presently no less than 20 billion l/day from the ocean. The large quantities of marine phytoplankton passing through the cooling systems of the two power plants studied were found greatly reduced in numbers (41.7 percent) and in volume (33.7 percent). There was no apparent reduction in phytoplankton stocks when the intake water was cooler than 15 0 C. Species diversity (H') in the effluent was consistently lower than in the influent. Temperature elevations up to 10 0 C increased the gross primary productivity by 37 percent when intake water temperatures were 19 0 C or cooler, and reduced productivity by 22 percent when ambient water temperatures were warmer than 21.5 0 C. Since heating was consistently less damaging when applied to relatively cold water, use by coastal power plants of deep sea-water for cooling is strongly advocated. (U.S.)

Water-tunnel studies of heat balance in swimming mako sharks.

Science.gov (United States)

Bernal, D; Sepulveda, C; Graham, J B

2001-12-01

The mako shark (Isurus oxyrinchus) has specialized vascular networks (retia mirabilia) forming counter-current heat exchangers that allow metabolic heat retention in certain regions of the body, including the aerobic, locomotor red muscle and the viscera. Red muscle, white muscle and stomach temperatures were measured in juvenile (5-13.6 kg) makos swimming steadily in a water tunnel and exposed to stepwise square-wave changes in ambient temperature (T(a)) to estimate the rates of heat transfer and to determine their capacity for the activity-independent control of heat balance. The rates of heat gain of red muscle during warming were significantly higher than the rates of heat loss during cooling, and neither the magnitude of the change in T(a) nor the direction of change in T(a) had a significant effect on red muscle latency time. Our findings for mako red muscle are similar to those recorded for tunas and suggest modulation of retial heat-exchange efficiency as the underlying mechanism controlling heat balance. However, the red muscle temperatures measured in swimming makos (0.3-3 degrees C above T(a)) are cooler than those measured previously in larger decked makos. Also, the finding of non-stable stomach temperatures contrasts with the predicted independence from T(a) recorded in telemetry studies of mako and white sharks. Our studies on live makos provide new evidence that, in addition to the unique convergent morphological properties between makos and tunas, there is a strong functional similarity in the mechanisms used to regulate heat transfer.

An optimal multivariable controller for transcritical CO2 refrigeration cycle with an adjustable ejector

International Nuclear Information System (INIS)

He, Yang; Deng, Jianqiang; Yang, Fusheng; Zhang, Zaoxiao

2017-01-01

Highlights: • Dynamic model for transcritical CO 2 ejector refrigeration system is developed. • A model-driven optimal multivariable controller is proposed. • Gas cooler pressure and cooling capacity are tracked independently. • Maximal performance for a given load is achieved by the optimal controller. - Abstract: The fixed ejector has to work under a restricted operating condition to keep its positive effectiveness on the transcritical CO 2 refrigeration cycle, and a controllable ejector will be helpful. In this paper, an optimal multivariable controller based on the dynamic model is proposed to improve transcritical CO 2 refrigeration cycle with an adjustable ejector (TCRAE). A nonlinear dynamic model is first developed to model the dynamic characteristic of TCRAE. The corresponding model linearization is carried out and the simulation results reproduce transient behavior of the nonlinear model very well. Based on the developed model, an optimal multivariable controller with a tracker based linear quadratic state feedback algorithm and a predictor using steepest descent method is designed. The controller is finally applied on the experimental apparatus and the performance is verified. Using the tracker only, the gas cooler pressure and chilled water outlet temperature (cooling capacity) are well tracked rejecting the disturbances from each other. Furthermore, by the predictor, the optimal gas cooler pressure for a constant cooling capacity is actually approached on the experimental apparatus with a settling time about 700 s.

Cooling systems for waste heat. Cooling systems, review and selection criteria. Kuehlsysteme fuer Abwaerme. Kuehlsysteme, Ueberblick und Auswahlkriterien

Energy Technology Data Exchange (ETDEWEB)

Mueller, W. (Jaeggi, Wallisellen (Switzerland))

1990-05-01

In many areas of ventilation, air-conditioning and refrigeration engineering, chemical and process engineering and energy production waste heat occurs. If a reduction in energy losses or heat recovery is not possible waste heat has to be drawn off through cooling systems. For this the following systems can be used: dry cooling systems, dry cooler with spray system, open-cycle wet cooler, hybrid dry cooler, and closed-cycle wet cooler. Particularly hybrid cooling systems can give acceptable solutions when the results with other systems are only unsatisfactory. (BWI).

Sound propagation in narrow tubes including effects of viscothermal and turbulent damping with application to charge air coolers

Science.gov (United States)

Knutsson, Magnus; Åbom, Mats

2009-02-01

Charge air coolers (CACs) are used on turbocharged internal combustion engines to enhance the overall gas-exchange performance. The cooling of the charged air results in higher density and thus volumetric efficiency. It is also important for petrol engines that the knock margin increases with reduced charge air temperature. A property that is still not very well investigated is the sound transmission through a CAC. The losses, due to viscous and thermal boundary layers as well as turbulence, in the narrow cooling tubes result in frequency dependent attenuation of the transmitted sound that is significant and dependent on the flow conditions. Normally, the cross-sections of the cooling tubes are neither circular nor rectangular, which is why no analytical solution accounting for a superimposed mean flow exists. The cross-dimensions of the connecting tanks, located on each side of the cooling tubes, are large compared to the diameters of the inlet and outlet ducts. Three-dimensional effects will therefore be important at frequencies significantly lower than the cut-on frequencies of the inlet/outlet ducts. In this study the two-dimensional finite element solution scheme for sound propagation in narrow tubes, including the effect of viscous and thermal boundary layers, originally derived by Astley and Cummings [Wave propagation in catalytic converters: Formulation of the problem and finite element scheme, Journal of Sound and Vibration 188 (5) (1995) 635-657] is used to extract two-ports to represent the cooling tubes. The approximate solutions for sound propagation, accounting for viscothermal and turbulent boundary layers derived by Dokumaci [Sound transmission in narrow pipes with superimposed uniform mean flow and acoustic modelling of automobile catalytic converters, Journal of Sound and Vibration 182 (5) (1995) 799-808] and Howe [The damping of sound by wall turbulent shear layers, Journal of the Acoustical Society of America 98 (3) (1995) 1723-1730], are

Biogenic elements in bottom sediments of lake Drukshiai - the cooler of Ignalina nuclear power plant

International Nuclear Information System (INIS)

Ilgevichiute, J.

1995-01-01

The accumulation and distribution of nitrogen, phosphorus, organic carbon, iron and calcium in sediments from different test - places of lake Drukshiai were investigated. The fractional composition of phosphorus and concentration of soluble phosphorus in liquid fraction of sediments and in water were determined. (author). 7 refs., 1 tab., 2 figs

Phonic and induced level of mutations and mutagenicity in bioorganisms habitating in the environs of Ignalina APP

International Nuclear Information System (INIS)

Lekevichius, R.; Morkunas, V.; Knabikas, A.

1992-01-01

The investigation of the extracts from the water, mud and hydrobionts of the lake Drukshiai before the construction of the Ignalina atomic power plant (1982-1984) and after its construction enabled to detect the moment of the build-up of mutagens in the hydrobionts (in 1986), when the extracts began to induce spot mutations in Salmonella typhimurium and exchanges of sister chromatids in human leukocytes in vitro. The mutagenicity of rain water, sewerage water and water from the cooler of the atomic power plant to drosophila and Salmonella typhimurium has been detected. The increments of mutations in the populations of Larus ridibundus and Microtus arvalis inhabiting the surroundings of the atomic power plant has not been noticed. (author). 4 figs., 4 refs

THE USE OF POROUS CERAMICS FOR EVAPORATIVE AND EVAPORATIVE – VAPOR –COMPRESSION SYSTEMS

Directory of Open Access Journals (Sweden)

Cheban D.N.

2013-04-01

Full Text Available The use of natural evaporative cooling is one of technical solutions of problem of energy efficiency in air conditioning systems. The use of evaporative cooling in the first combined cooling stage allows reducing the load on the condenser of the cooling machine due to reducing of the condensing temperature. This combination allows the use of this type of system in any climatic conditions, including regions with small water resources. Multi-porous ceramic structure is used in evaporative air coolers and water coolers in this case. The objective of this paper is to show advantages of the using of porous ceramic as a working attachment, and to show advantages of the proposed scheme of compression-evaporation systems in comparison with standard vapor compression systems. Experimental research proved the fact, that in the film mode cooling efficiency of air flow is between EA=0,6÷0,7 and is slightly dependent of water flow. For countries with hot and dry climate where reserves of water are limited, it is recommended to use cyclical regime with EA≈0,65 value, or to use channel regime with a value of EA≈0,55. This leads to considerable energy savings. It has been determined, that combined air conditioning system is completely closed on the consumption of water at the parameters of the outside air equal to tA =32ºC and XA>13g/kg (in system with direct evaporative cooling machine, and tA=32ºC and XA>12g/kg (in system with indirect evaporative cooling machine. With these parameters, the cost of water in evaporative cooling stage can be fully compensated by condensate from the evaporator chiller.

Study on dew point evaporative cooling system with counter-flow configuration

International Nuclear Information System (INIS)

Lin, J.; Thu, K.; Bui, T.D.; Wang, R.Z.; Ng, K.C.; Chua, K.J.

2016-01-01

Highlights: • Numerical model for a dew point evaporative cooler verified with experiments. • Saturation point of the working air is independent of the inlet air conditions. • The intensity of cooling capacity and water evaporation are studied. • The overall heat transfer coefficient for the working air is analyzed. • The conditions to achieve sub-wet bulb cooling are examined. - Abstract: Dew point evaporative cooling has great potential as a disruptive process for sensible cooling of air below its entering wet bulb temperature. This paper presents an improved mathematical model for a single-stage dew point evaporative cooler in a counter-flow configuration. Longitudinal heat conduction and mass diffusion of the air streams, channel plate and water film, as well as the temperature difference between the plate and water film, are accounted for in the model. Predictions of the product air temperature are validated using three sets of experimental data within a discrepancy of 4%. The cooler’s heat and mass transfer process is analyzed in terms of its cooling capacity intensity, water evaporation intensity, and overall heat transfer coefficient along the channel. Parametric studies are conducted at different geometric and operating conditions. For the conditions evaluated, the study reveals that (1) the saturation point of the working air occurs at a fixed point regardless of the inlet air conditions, and it is mainly influenced by the working air ratio and channel height; (2) the intensity of the water evaporation approaches a minimum at 0.2 to 0.3 m from the entrance; (3) the wet channel can be separated into two zones, and the overall heat transfer coefficient is above 100 W/(m"2·K) after the temperature of water film becomes higher than the working air temperature.

Effects of Mesocyclops longisetus (Copepoda:Cyclopidae) on mosquitoes that inhabit tires: influence of litter type, quality, and quantity.

Science.gov (United States)

Schreiber, E T; Hallmon, C F; Eskridge, K M; Marten, G G

1996-12-01

A 59-week study was conducted to evaluate the impact of adult Mesocyclops longisetus populations on larval mosquito species inhabiting tires. Greater than 90% reduction of number of 1st and 2nd instars was recorded by 4 wk with 90% reduction of number of 3rd and 4th instars after 7 wk. Reduced control was noted with the onset of cooler winter water temperature. Overall. a 52% reduction in the number of 1st and 2nd instars was achieved, and a 57% reduction was noted in number of 3rd- and 4th-instar mosquito larvae. Cooler temperatures resulted in a decline of adult Mesocyclops, which resulted in reduced larval control. Significantly greater numbers of Mesocyclops adults were collected in tires with either new litter or heavy amounts of litter regardless of litter type. Lastly, litter type, either oak leaves or pine needles, did not influence mosquito reduction or abundance of Mesocyclops populations.

Study on blast furnace cooling stave for various refractory linings based on numerical modeling

International Nuclear Information System (INIS)

Mohanty, T R; Sahoo, S K; Moharana, M K

2016-01-01

Cooling technology for refractory lining of blast furnace is very important for the metallurgical industry, because it can substantially increase output and operation life of furnaces. A three dimensional mathematical model for the temperature field of the blast furnace stave cooler with refractory lining has been developed and analyzed. The temperature and heat dissipated by stave cooler is examined by using the finite element method. The cast steel stave is studied and computational analysis is made to know the effect of the cooling water velocity, temperature, and the lining material on the maximum temperature of the stave hot surface. The refractory lining materials, which are used in this experiment, are high alumina bricks with different stave materials (copper, aluminum and cast iron). The obtained numerical calculations are compared with that obtained from experiments performed at Rourkela Steel Plant, Odisha taking a stave in belly zone having maximum heat load shows very good agreement. (paper)

Characterization of commercial building appliances. Final report

Energy Technology Data Exchange (ETDEWEB)

Patel, R.F.; Teagan, P.W.; Dieckmann, J.T.

1993-08-01

This study focuses on ``other`` end-uses category. The purpose of this study was to determine the relative importance of energy end-use functions other than HVAC and lighting for commercial buildings, and to identify general avenues and approaches for energy use reduction. Specific energy consuming technologies addressed include non-HVAC and lighting technologies in commercial buildings with significant energy use to warrant detailed analyses. The end-uses include office equipment, refrigeration, water heating, cooking, vending machines, water coolers, laundry equipment and electronics other than office equipment. The building types include offices, retail, restaurants, schools, hospitals, hotels/motels, grocery stores, and warehouses.

The spatial distribution of silicoflagellates in the region of the Gulf Stream warm-core ring 82B: application to water mass tracer studies