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Sample records for absorption cooling cycle

  1. A Novel Absorption Cycle for Combined Water Heating, Dehumidification, and Evaporative Cooling

    SciTech Connect

    CHUGH, Devesh; Gluesenkamp, Kyle R; Abdelaziz, Omar; Moghaddam, Saeed

    2014-01-01

    In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser. The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the

  2. Design, evaluation and recommedation effort relating to the modification of a residential 3-ton absorption cycle cooling unit for operation with solar energy

    NASA Technical Reports Server (NTRS)

    Merrick, R. H.; Anderson, P. P.

    1973-01-01

    The possible use of solar energy powered absorption units to provide cooling and heating of residential buildings is studied. Both, the ammonia-water and the water-lithium bromide cycles, are considered. It is shown that the air cooled ammonia water unit does not meet the criteria for COP and pump power on the cooling cycle and the heat obtained from it acting as a heat pump is at too low a temperature. If the ammonia machine is water cooled it will meet the design criteria for cooling but can not supply the heating needs. The water cooled lithium bromide unit meets the specified performance for cooling with appreciably lower generator temperatures and without a mechanical solution pump. It is recommeded that in the demonstration project a direct expansion lithium bromide unit be used for cooling and an auxiliary duct coil using the solar heated water be employed for heating.

  3. The economics of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1978-01-01

    Analytic procedure evaluates cost of combining absorption-cycle chiller with solar-energy system in residential or commercial application. Procedure assumes that solar-energy system already exists to heat building and that cooling system must be added. Decision is whether to cool building with conventional vapor-compression-cycle chiller or to use solar-energy system to provide heat input to absorption chiller.

  4. Closed-Cycle He-Cooled Absorption Cells Designed for a Bruker IFS-125HR: First Results Between 79 K and 297K

    NASA Astrophysics Data System (ADS)

    Mantz, Arlan W.; Sung, Keeyoon; Brown, Linda R.; Crawford, Timothy J.; Smith, Mary Ann H.; Devi, V. Malathy; Benner, D. Chris

    2010-06-01

    Gas absorption cells specifically designed to achieve stable temperatures down to ˜70 K to fit inside the sample compartment of an evacuated Bruker (IFS-125HR) Fourier Transform spectrometer (FTS) have been developed at Connecticut College, and tested at the Jet Propulsion Laboratory (JPL). In operation, the temperature-controlled cooling by a closed-cycle helium refrigerator achieved a temperature stability of ±0.01 K. The unwanted absorption features initially observed from cryo-deposits formed on the outside cell windows were eliminated by adding an internal vacuum shroud box around the coolable cell to isolate it from residual gases in the evacuated FTS chambers. The effects of vibrations arising from the closed-cycle helium refrigerator upon the FTS spectra were characterized. Using this set up, high resolution spectra of several methane isotopologues (such as 12CH_4, 13CH_4 and 12CH_3D) broadened by N_2, were recorded in the 1230 to 1850 cm-1 spectral region. Such data are needed to characterize the temperature dependence of line shapes at very low temperatures for remote sensing of outer planets and their moons. Results from the initial analysis of the R(2) manifold of the ν_4 fundamental band of 13CH_4 are discussed to examine whether the N_2-broadened half width coefficients follow a simple exponential temperature-dependence over the entire 80 - 296 K temperature range. This initial test was very successful, proving that a high precision Fourier transform spectrometer can be easily configured for spectroscopic studies at very low temperatures relevant to planetary atmospheres. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  5. Closed-cycle He-cooled Absorption Cells Designed For A Bruker Ifs-125hr: First Results Between 79 - 297 K

    NASA Astrophysics Data System (ADS)

    Sung, Keeyoon; Mantz, A. W.; Smith, M. A. H.; Brown, L. R.; Crawford, T. J.; Malathy Devi, V.; Benner, D. Chris

    2010-10-01

    Gas absorption cells specifically designed to achieve stable temperatures down to 66K were developed at Connecticut College to fit inside the sample compartment of an evacuated Bruker (IFS-125HR) Fourier Transform spectrometer (FTS) at the Jet Propulsion Laboratory. The temperature-controlled cooling by a closed-cycle helium refrigerator achieved a temperature stability of ±0.01 K. Such temperature control is essential to characterize the temperature dependence of line shapes at the very low temperatures found in outer planets and their moons. In operation, the effects of vibrations arising from the closed-cycle helium refrigerator upon the FTS spectra were minimized. Initial unwanted absorption features from cryo-deposits on the cell windows were eliminated by adding a separately-pumped vacuum shroud box around the coolable cell to isolate it from residual gases in the evacuated FTS chambers. Using this setup, high resolution spectra of several methane isotopologues (12CH4, 13CH4 and 12CH3D) broadened by N2, were recorded in the 1230 to 1850 cm-1 spectral region. Initial analysis of the R(2) manifold of the v4 fundamental band of 13CH4 examined whether the N2-broadened half width coefficients follow a simple power-law temperature-dependence over the entire 80 - 296 K temperature range. The results from this work were published by Sung et al. [1]. Low-temperature spectra of ethane [2-3] and carbon monoxide have also been recorded. This research is supported by NASA's Planetary Atmospheres Program. [1] K. Sung et al., J. Mol. Spectrosc. (2010) doi:10.1016/j.jms.2010.05.004. [2] V. Malathy Devi et al., JQSRT (2010) submitted. [3] L. R. Brown et al., adjacent poster.

  6. Air cooled absorption chillers for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Biermann, W. J.; Reimann, R. C.

    1982-03-01

    The chemical composition of a 'best' absorption refrigerant system is identified, and those properties of the system necessary to design hot water operated, air cooled chilling equipment are determined. Air cooled chillers from single family residential sizes into the commercial rooftop size range are designed and operated.

  7. Enhanced absorption cycle computer model

    NASA Astrophysics Data System (ADS)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  8. Advanced regenerative absorption refrigeration cycles

    DOEpatents

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  9. Closed cycle desiccant cooling system

    NASA Astrophysics Data System (ADS)

    Tchernev, D. I.; Emerson, D. T.

    1986-10-01

    The breadboard prototype of a closed cycle desiccant cooling system was designed, constructed and its performance tested. The system combines the sorption properties of solid zeolite/refrigerant vapor pairs with the principle of regenerative heat exchangers. Since solid zeolites are difficult to move in vacuum tight containers and in order to avoid intermittent operation, the desiccant is housed in two separate containers which are alternately heated and cooled by a heat transfer fluid. Using the principle of energy regeneration, the heat removed from the container being cooled is recycled in the container being heated. The breadboard system, with 90 pounds of zeolite, demonstrated a recycling efficiency of 75%, while the system capacity was 2,000 Btu/hr. This significantly increased the system thermal Coefficient of Performance (COP) to 1.1 at ARI conditions from the single container thermal COP of 0.4.

  10. Adopting steam-driven absorption cooling

    SciTech Connect

    Rose, D.T.; Perez-Blanco, H.; Ryan, W.A.

    1995-10-01

    Proper installation, water quality, and maintenance are essential to operating a cost-effective absorption system. Concerns about energy efficiency and the use of chlorofluorocarbons have led to the greater use of absorption machines for cooling applications. These machines, which reclaim condenser or exhaust-gas heat, are used in the most advanced cogeneration systems. Although absorption technology has a long history--with mixed success--its versatility has only recently begun to payoff.

  11. GAX absorption cycle design process

    SciTech Connect

    Priedeman, D.K.; Christensen, R.N.

    1999-07-01

    This paper presents an absorption system design process that relies on computer simulations that are validated by experimental findings. An ammonia-water absorption heat pump cycle at 3 refrigeration tons (RT) and chillers at 3.3 RT and 5 RT (10.5 kW, 11.6 kW, and 17.6 kW) were initially modeled and then built and tested. The experimental results were used to calibrate both the cycle simulation and the component simulations, yielding computer design routines that could accurately predict component and cycle performance. Each system was a generator-absorber heat exchange (GAX) cycle, and all were sized for residential and light commercial use, where very little absorption equipment is currently used. The specific findings of the 5 RT (17.6 kW) chiller are presented. Modeling incorporated a heat loss from the gas-fired generator and pressure drops in both the evaporator and absorber. Simulation results and experimental findings agreed closely and validated the modeling method and simulation software.

  12. Rankine-cycle heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Design for domestic or commercial solar heating and cooling system based on rankine heat pump cycle includes detailed drawings, performance data, equipment specifications, and other pertinent information.

  13. Solar absorption cooling plant in Seville

    SciTech Connect

    Bermejo, Pablo; Pino, Francisco Javier; Rosa, Felipe

    2010-08-15

    A solar/gas cooling plant at the Engineering School of Seville (Spain) was tested during the period 2008-2009. The system is composed of a double-effect LiBr + water absorption chiller of 174 kW nominal cooling capacity, powered by: (1) a pressurized hot water flow delivered by mean of a 352 m{sup 2} solar field of a linear concentrating Fresnel collector and (2) a direct-fired natural gas burner. The objective of the project is to indentify design improvements for future plants and to serve as a guideline. We focused our attention on the solar collector size and dirtiness, climatology, piping heat losses, operation control and coupling between solar collector and chiller. The daily average Fresnel collector efficiency was 0.35 with a maximum of 0.4. The absorption chiller operated with a daily average coefficient of performance of 1.1-1.25, where the solar energy represented the 75% of generator's total heat input, and the solar cooling ratio (quotient between useful cooling and insolation incident on the solar field) was 0.44. (author)

  14. Fundamental Study of Absorption Cycle without Electric Solution Pump

    NASA Astrophysics Data System (ADS)

    Tsujimori, Atsushi; Sato, Kazuo; Nakao, Kazushige; Ohgushi, Tetsuro; Katsuta, Masafumi

    The absorption refrigerant cycle has been used in Japan, as energy shortage problem is more and more serious and environmental protection is of increasing importance. This type of air conditioner and chiller consume less electric power input than the electric one. However, the absorption refrigerator of large cooling capacity consumes some electric power with the required facility. Then in this research, the absorption cycle without the electric solution pump is proposed using a capillary pump and the possibility of making this cycle running using LiBr solution as a working fluid is investigated. As a result, it was found that the absorption cycle could be reached using a capillary wick in the generator to circulate the refrigerant and kept the strong and weak solution low pressure.

  15. Open cycle lithium chloride cooling system

    NASA Astrophysics Data System (ADS)

    Lenz, T. G.; Loef, G. O. G.; Iyer, R.; Wenger, J.

    1983-05-01

    A lithium chloride open cycle absorption chiller has been designed, built and tested. Solution reconcentration takes place in a small counter current packed column supplied with solar heated air. Removal of noncondensable gases that enter the chiller dissolved in the strong solution and the make-up refrigerant streams is accomplished by a liquid-jet ejector and a small vacuum pump. Cooling capacities approaching 1.4 tons and COP levels of 0.58 have been achieved at non-optimum operating conditions. Test results from preliminary system operation suggest that mass transfer processes in both the packed column reconcentrator and the absorber are controlled by concentration gradients in the lithium chloride solution. Liquid phase controlled mass transfer dictates an operating strategy different from the previously assumed gas phase controlled process to obtain maximum rates of evaporation in the packed column. Determination of optimal operating conditions leading to decreased electrical power consumption and improved cooling capacity and coefficient of performance will require further analysis and testing.

  16. Overview-absorption/Rankine solar cooling program

    NASA Astrophysics Data System (ADS)

    Wahlig, M.; Heitz, A.; Boyce, B.

    1980-03-01

    The tasks being performed in the absorption and Rankine program areas run the gamut from basic work on fluids to development of chillers and chiller components, to field and reliability testing of complete cooling systems. In the absorption program, there are six current and five essentially completed projects. In the Rankine program, there are five current projects directly supported by DOE, and three projects funded through and managed by NASA/MSFC (Manned Space Flight Center, Huntsville, Alabama). The basic features of these projects are discussed. The systems under development in five of these current projects were selected for field testing in the SOLERAS program, a joint US-Saudi Arabian enterprise. Some technical highlights of the program are presented.

  17. Rankine-cycle solar-cooling systems

    NASA Technical Reports Server (NTRS)

    Weathers, H. M.

    1979-01-01

    Report reviews progress made by three contractors to Marshall Space Flight Center and Department of Energy in developing Rankine-cycle machines for solar cooling and testing of commercially available equipment involved.

  18. Triple-effect absorption chiller cycles

    SciTech Connect

    DeVault, R.C.; Grossman, G.

    1992-06-01

    Gas-fired absorption chillers are widely used for air-conditioning buildings. Even the highest efficiency double-effect absorption chillers used more primary energy for air-conditioning buildings than the better electric chillers. Two different triple-effect absorption chiller cycles are capable of substantial performance improvement over equivalent double-effect cycles. One cycle uses two condensers and two absorbers to achieve the ``triple effect.`` A second cycle, the Double-Condenser Coupled Triple-Effect, uses three condensers as well as a third condenser subcooler (which exchanges heat with the lowest temperature first-effect generator). These triple-effect absorption cycles have the potential to be as energy efficient (on a primary fuel basis) as the best electric chillers. 19 refs.

  19. Triple-effect absorption chiller cycles

    SciTech Connect

    DeVault, R.C. ); Grossman, G. )

    1992-01-01

    Gas-fired absorption chillers are widely used for air-conditioning buildings. Even the highest efficiency double-effect absorption chillers used more primary energy for air-conditioning buildings than the better electric chillers. Two different triple-effect absorption chiller cycles are capable of substantial performance improvement over equivalent double-effect cycles. One cycle uses two condensers and two absorbers to achieve the triple effect.'' A second cycle, the Double-Condenser Coupled Triple-Effect, uses three condensers as well as a third condenser subcooler (which exchanges heat with the lowest temperature first-effect generator). These triple-effect absorption cycles have the potential to be as energy efficient (on a primary fuel basis) as the best electric chillers. 19 refs.

  20. Preformance Analysis of NH3-H2O Absorption Cycle

    NASA Astrophysics Data System (ADS)

    Tsujimori, Atsushi; Ozaki, Eiichi

    Different from H2O-LiBr absorption cycle, it is necessary to have rectifier between generator and condenser in NH3-H2O absorption cycle, because there mixes some steam in refrigerant vapor in the process of regenerating refrigerant from the ammonia strong aqueous solution. And in some case ex. partial load or heating, the efficiency of rectifier might decrease, if the flow rate of refrigerant vapor and ammonia aqueous solution decrease. As a result, steam flow into condenser with ammonia refrigerant vapor, which reduces cycle COPs of cooling and heating. Accordingly in order to evaluate the effect of ammonia concentration in refrigerant for the performance of NH3-H2O absorption heat pump, the simple design approach of modeling condenser and evaporator is introduced in this paper. In the model, the calculation of heat rate in condenser and evaporator was simplified considering the characteristic of NH3-H2O liquid-vapor equilibrium. Then the simulation for cycle perforance based on GAX absorption cycle was made using the efficiency of rectifier that established the ammonia concentration in refrigerant and it was derived that 3 [%] decrease of ammonia concentration in refrigerant induced 15 [%] decrcase of cooling COP and 7 [%] decrease of heating COP and that there existed the most suitable circulation ratio for each ammonia concentration in refrigerant.

  1. Gemini helium closed cycle cooling system

    NASA Astrophysics Data System (ADS)

    Lazo, Manuel; Galvez, Ramon; Rogers, Rolando; Solis, Hernan; Tapia, Eduardo; Maltes, Diego; Collins, Paul; White, John; Cavedoni, Chas; Yamasaki, Chris; Sheehan, Michael P.; Walls, Brian

    2008-07-01

    The Gemini Observatory presents the Helium Closed Cycle Cooling System that provides cooling capacity at cryogenic temperatures for instruments and detectors. It is implemented by running three independent helium closed cycle cooling circuits with several banks of compressors in parallel to continuously supply high purity helium gas to cryocoolers located about 100-120 meters apart. This poster describes how the system has been implemented, the required helium pressures and gas flow to reach cryogenic temperature, the performance it has achieved, the helium compressors and cryocoolers in use and the level of vibration the cryocoolers produce in the telescope environment. The poster also describes the new technology for cryocoolers that Gemini is considering in the development of new instruments.

  2. Enhanced absorption cycle computer model. Final report

    SciTech Connect

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperatures boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorptions systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system`s components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H{sub 2}O triple-effect cycles, LiCl-H{sub 2}O solar-powered open absorption cycles, and NH{sub 3}-H{sub 2}O single-effect and generator-absorber heat exchange cycles. An appendix contains the User`s Manual.

  3. Cycle Simulation of HotWater Fired Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Esaki, Shuji; Iramina, Kazuyasu; Kobayashi, Takahiro; Ohnou, Masayuki; Kaneko, Toshiyuki; Soga, Takashi

    The design limits were examined to determine the lowest temperature for hot water that can be used as a heat source to drive a hot water fired absorption chiller. Advantage was taken of the fact that the cycle calculation method using the minimum temperature difference is quite effective. This minimum temperature difference was the lower of the two temperature differences used to get the logarithmic mean temperature difference that need to design the evaporator, absorber, condenser and generator in an absorption refrigerator. This report proposes a new solution algorithm employing this minimum temperature difference to make a cycle simulation of the hot water fired absorption chiller. It shows the lowest usable temperature for hot water and makes clear the chilled water and cooling water temperature conditions that can provide the lowest temperature.

  4. Overview of Resources for Geothermal Absorption Cooling for Buildings

    SciTech Connect

    Liu, Xiaobing; Gluesenkamp, Kyle R; Mehdizadeh Momen, Ayyoub

    2015-06-01

    This report summarizes the results of a literature review in three areas: available low-temperature/coproduced geothermal resources in the United States, energy use for space conditioning in commercial buildings, and state of the art of geothermal absorption cooling.

  5. Cycle Analysis using Exhaust Heat of SOFC and Turbine Combined Cycle by Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Takezawa, Shinya; Wakahara, Kenji; Araki, Takuto; Onda, Kazuo; Nagata, Susumu

    A power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300°C. So it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. Then, we propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500kW class SOFC, the bottoming single-effect absorption chiller can produce the refrigerating capacity of about 120kW, and the double-effect absorption chiller can produce a little higher refrigerating capacity of about 130kW without any additional fuel. But the double-effect absorption chiller became more expensive and complex than the single-effect chiller.

  6. Water cooled absorption chillers for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Biermann, W. J.; Reimann, R. C.

    1982-03-01

    A broad line of absorption chillers designed to operate with hot fluids at as low a temperature as practical while rejecting heat to a stream of water was developed. A packaging concept for solar application in which controls, pumps, valves and other system components could be factor assembled into a unitary solar module was investigated.

  7. Site dependent factors affecting the economic feasibility of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1978-01-01

    A procedure was developed to evaluate the cost effectiveness of combining an absorption cycle chiller with a solar energy system. A basic assumption of the procedure is that a solar energy system exists for meeting the heating load of the building, and that the building must be cooled. The decision to be made is to either cool the building with a conventional vapor compression cycle chiller or to use the existing solar energy system to provide a heat input to the absorption chiller. Two methods of meeting the cooling load not supplied by solar energy were considered. In the first method, heat is supplied to the absorption chiller by a boiler using fossil fuel. In the second method, the load not met by solar energy is net by a conventional vapor compression chiller. In addition, the procedure can consider waste heat as another form of auxiliary energy. Commercial applications of solar cooling with an absorption chiller were found to be more cost effective than the residential applications. In general, it was found that the larger the chiller, the more economically feasible it would be. Also, it was found that a conventional vapor compression chiller is a viable alternative for the auxiliary cooling source, especially for the larger chillers. The results of the analysis gives a relative rating of the sites considered as to their economic feasibility of solar cooling.

  8. Water-lithium bromide double-effect absorption cooling analysis

    NASA Astrophysics Data System (ADS)

    Vliet, G. C.; Lawson, M. B.; Lithgow, R. A.

    1980-12-01

    A numerical model was developed for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine and was used to determine the effect of the various design and input variables on the absorption unit performance. The performance parameters considered were coefficient of performance and cooling capacity. The variables considered include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods. The performance sensitivity study indicates that the distribution of heat exchanger area among the various (seven) heat exchange components is a very important design consideration. Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity. The model was used to predict the performance of the Trane absorption unit with fairly good accuracy.

  9. Cascade Reverse Osmosis Air Conditioning System: Cascade Reverse Osmosis and the Absorption Osmosis Cycle

    SciTech Connect

    2010-09-01

    BEETIT Project: Battelle is developing a new air conditioning system that uses a cascade reverse osmosis (RO)-based absorption cycle. Analyses show that this new cycle can be as much as 60% more efficient than vapor compression, which is used in 90% of air conditioners. Traditional vapor-compression systems use polluting liquids for a cooling effect. Absorption cycles use benign refrigerants such as water, which is absorbed in a salt solution and pumped as liquid—replacing compression of vapor. The refrigerant is subsequently separated from absorbing salt using heat for re-use in the cooling cycle. Battelle is replacing thermal separation of refrigerant with a more efficient reverse osmosis process. Research has shown that the cycle is possible, but further investment will be needed to reduce the number of cascade reverse osmosis stages and therefore cost.

  10. Some heat pump concepts for residual heat utilization. [Absorption-cycle and open-cycle systems

    SciTech Connect

    Perez-Blanco, H.; Chen, F. C.

    1980-01-01

    Large quantities of low temperature heat in the industrial sector are rejected in the cooling water, condensate, and process water streams. While the energy rejected in these streams at temperatures between 40 and 80/sup 0/C amounts to 2.95 x 10/sup 9/ GJ/y, 2.42 x 10/sup 9/ GJ/y of process energy in the form of hot water and steam are needed in the United States. Industrial heat pumps, that recover the low temperature heat energy and upgrade it to a more usable temperature level, may improve the energy supply and demand situation. Two heat activated heat pump concepts - an absorption cycle system and an open cycle system are analyzed from the conceptual systems design and energy savings point of view. The results of the analysis and further research needs are presented.

  11. Dilution cycle control for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    A dilution cycle control system for an absorption refrigeration system is disclosed. The control system includes a time delay relay for sensing shutdown of the absorption refrigeration system and for generating a control signal only after expiration of a preselected time period measured from the sensed shutdown of the absorption refrigeration system, during which the absorption refrigeration system is not restarted. A dilution cycle for the absorption refrigeration system is initiated in response to generation of a control signal by the time delay relay. This control system is particularly suitable for use with an absorption refrigeration system which is frequently cycled on and off since the time delay provided by the control system prevents needless dilution of the absorption refrigeration system when the system is turned off for only a short period of time and then is turned back on.

  12. Advances in open-cycle solid desiccant cooling

    SciTech Connect

    Penney, T R; Maclaine-cross, I

    1985-05-01

    Of the solar cooling options available open cycle solid desiccant cooling looks very promising. A brief review of the experimental and analytical efforts to date shows that within the last 10 years thermal performance has doubled. Research centers have been developed to explore new materials and geometry options and to improve and validate mathematical models that can be used by design engineers to develop new product lines. Typical results from the Solar Energy Research Institute's (SERI) Desiccant Cooling Research Program are shown. Innovative ideas for new cycles and spinoff benefits provide incentives to continue research in this promising field.

  13. Optimum hot water temperature for absorption solar cooling

    SciTech Connect

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R.; Zacarias, A.

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  15. Site-dependent factors affecting the economic feasibility of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1977-01-01

    A procedure has been developed which can be used to determine the economic feasibility of solar powered absorption cooling systems. This procedure has been used in a study to investigate the influence of the site-dependent parameters on the economic feasibility of solar absorption cooling. The purpose of this study was to make preliminary site selections for solar powered absorption cooling systems. This paper summarizes the results of that study.

  16. Absorption heat pump in heating and cooling systems of buildings

    NASA Astrophysics Data System (ADS)

    Aho, I.

    This report focuses on the operation and applicability of absorption heat pumps (AHP) in building heating and cooling systems. Examples are presented on heating systems of residential buildings and a heating/cooling system of an office building. Despite the limitations of present AHP technology the examples assume AHPs which produce heat at an appropriate temperature level for each application. According to the calculations the primary energy saving potential of AHPs in building specific heat production is 20 to 40 percent. For AHPs coupled with district heating systems the primary energy saving potential can not be unambiguously defined because it is influenced by the production form of district heat, the influence of district heat demand on power generation etc. For the time being economical aspects limit the application potential of AHPs. The profitability of AHP investments is quite poor because of present energy prices, the price ratio of different energy forms and the high investment cost of AHP-systems. The environmental impact of AHPs depend on the fuel used in the generator. Using fuel oil or gas will decrease sulphur and particle emissions but might increase the emissions of NO(x) and hydrocarbons because of the smaller size of combustion units. CFC-emissions will be decreased because AHPs apply alternative refrigerants.

  17. Integrated vacuum absorption steam cycle gas separation

    SciTech Connect

    Chen, Shiaguo; Lu, Yonggi; Rostam-Abadi, Massoud

    2011-11-22

    Methods and systems for separating a targeted gas from a gas stream emitted from a power plant. The gas stream is brought into contact with an absorption solution to preferentially absorb the targeted gas to be separated from the gas stream so that an absorbed gas is present within the absorption solution. This provides a gas-rich solution, which is introduced into a stripper. Low pressure exhaust steam from a low pressure steam turbine of the power plant is injected into the stripper with the gas-rich solution. The absorbed gas from the gas-rich solution is stripped in the stripper using the injected low pressure steam to provide a gas stream containing the targeted gas. The stripper is at or near vacuum. Water vapor in a gas stream from the stripper is condensed in a condenser operating at a pressure lower than the stripper to concentrate the targeted gas. Condensed water is separated from the concentrated targeted gas.

  18. Emissions-critical charge cooling using an organic rankine cycle

    DOEpatents

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-07-15

    The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.

  19. Modelling aging effects on a thermal cycling absorption process column

    SciTech Connect

    Laquerbe, C.; Contreras, S.; Demoment, J.

    2008-07-15

    Palladium coated on alumina is used in hydrogen separation systems operated at CEA/Valduc, and more particularly in Thermal Cycling Absorption Process columns. With such materials, tritium decay is known to induce aging effects which have direct side effects on hydrogen isotopes absorption isotherms. Furthermore in a TCAP column, aging occurs in an heterogeneous way. The possible impacts of these intrinsic material evolutions on the separation performances are investigated here through a numerical approach. (authors)

  20. Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

    NASA Astrophysics Data System (ADS)

    Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

    2016-02-01

    A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

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

    SciTech Connect

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

    1985-05-01

    The performance of a prototype 3 ton cooling capacity air-cooled lithium bromide/water absorption chiller was tested using an absorption chiller test facility which was modified to expand its testing capabilities to include air-cooled chillers in addition to water-cooled chillers. Temperatures of the three externally supplied fluid loops: hot water, chilled water, and cooling air, were varied in order to determine the effects this would have on the two principal measures of chiller performance: cooling capacity and thermal coefficient of performance (COP). A number of interrelated factors were identified as contributing to less than expected performance. For comparison, experimental correlations of other investigators for this and other similar absorption chillers are presented. These have been plotted as both contour and three-dimensional performance maps in order to more clearly show the functional dependence of the chiller performance on the fluid loop temperatures.

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

    NASA Astrophysics Data System (ADS)

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

    1985-05-01

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

  3. Effects of cooling time on a closed LWR fuel cycle

    SciTech Connect

    Arnold, R. P.; Forsberg, C. W.; Shwageraus, E.

    2012-07-01

    In this study, the effects of cooling time prior to reprocessing spent LWR fuel has on the reactor physics characteristics of a PWR fully loaded with homogeneously mixed U-Pu or U-TRU oxide (MOX) fuel is examined. A reactor physics analysis was completed using the CASM04e code. A void reactivity feedback coefficient analysis was also completed for an infinite lattice of fresh fuel assemblies. Some useful conclusions can be made regarding the effect that cooling time prior to reprocessing spent LWR fuel has on a closed homogeneous MOX fuel cycle. The computational analysis shows that it is more neutronically efficient to reprocess cooled spent fuel into homogeneous MOX fuel rods earlier rather than later as the fissile fuel content decreases with time. Also, the number of spent fuel rods needed to fabricate one MOX fuel rod increases as cooling time increases. In the case of TRU MOX fuel, with time, there is an economic tradeoff between fuel handling difficulty and higher throughput of fuel to be reprocessed. The void coefficient analysis shows that the void coefficient becomes progressively more restrictive on fuel Pu content with increasing spent fuel cooling time before reprocessing. (authors)

  4. ABSORPTIONS IN THE VISIBLE OF PROTONATED PYRENE COLLISIONALLY COOLED TO 15 K

    SciTech Connect

    Hardy, F.-X.; Gause, O.; Rice, C. A.; Maier, J. P.

    2013-12-01

    Protonated polycyclic hydrocarbons have been added to the list of suggested carriers of diffuse interstellar absorptions. To test this proposition requires laboratory spectra measured under interstellar conditions, in particular with the rotational and vibrational degrees of freedom equilibrated to low temperatures. This has been achieved for protonated pyrene with absorption bands in the visible, using an ion trap and collisional cooling to ≈15 K. A two-photon excitation-dissociation scheme was employed to record the (1) {sup 1} A' ← X {sup 1} A' electronic spectrum on around 10{sup 5} ions per duty cycle. The origin band of the absorption spectrum of this relatively large polycyclic aromatic species with 27 atoms is located at 4858.86 Å. Two further comparably intense spectral features are present at 4834.48 and 4809.32 Å. This is one of the largest protonated aromatics studied in the gas phase and compared to astronomical observations; however, it is not a carrier of known diffuse interstellar bands.

  5. Brayton Cycle for High-Temperature Gas-Cooled Reactors

    SciTech Connect

    Oh, Chang H.; Moore, Richard L.

    2005-03-15

    This paper describes research on improving the Brayton cycle efficiency for a high-temperature gas-cooled reactor (HTGR). In this study, we are investigating the efficiency of an indirect helium Brayton cycle for the power conversion side of an HTGR power plant. A reference case based on a 250-MW(thermal) pebble bed HTGR was developed using helium gas as a working fluid in both the primary and power conversion sides. The commercial computer code HYSYS was used for process optimization. A numerical model using the Visual-Basic (V-B) computer language was also developed to assist in the evaluation of the Brayton cycle efficiency. Results from both the HYSYS simulation and the V-B model were compared with Japanese calculations based on the 300-MW(electric) Gas Turbine High-Temperature Reactor (GTHTR) that was developed by the Japan Atomic Energy Research Institute. After benchmarking our models, parametric investigations were performed to see the effect of important parameters on the cycle efficiency. We also investigated single-shaft versus multiple-shaft arrangements for the turbomachinery. The results from this study are applicable to other reactor concepts such as fast gas-cooled reactors, supercritical water reactors, and others.The ultimate goal of this study is to use other fluids such as supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency over that of the helium Brayton cycle. This study is in progress, and the results will be published in a subsequent paper.

  6. Brayton Cycle for High Temperature Gas-Cooled Reactors

    SciTech Connect

    Chang Oh

    2005-03-01

    This paper describes research on improving the Brayton cycle efficiency for a high-temperature gas-cooled reactor (HTGR). In this study, we are investigating the efficiency of an indirect helium Brayton cycle for the power conversion side of an HTGR power plant. A reference case based on a 250-MW(thermal) pebble bed HTGR was developed using helium gas as a working fluid in both the primary and power conversion sides. The commercial computer code HYSYS was used for process optimization. A numerical model using the Visual-Basic (V-B) computer language was also developed to assist in the evaluation of the Brayton cycle efficiency. Results from both the HYSYS simulation and the V-B model were compared with Japanese calculations based on the 300-MW(electric) Gas Turbine High-Temperature Reactor (GTHTR) that was developed by the Japan Atomic Energy Research Institute. After benchmarking our models, parametric investigations were performed to see the effect of important parameters on the cycle efficiency. We also investigated single-shaft versus multiple-shaft arrangements for the turbomachinery. The results from this study are applicable to other reactor concepts such as fast gas-cooled reactors, supercritical water reactors, and others. The ultimate goal of this study is to use other fluids such as supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency over that of the helium Brayton cycle. This study is in progress, and the results will be published in a subsequent paper.

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

    NASA Astrophysics Data System (ADS)

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

    1984-02-01

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

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

    EPA Science Inventory

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

  9. Operating data on a novel absorption refrigeration cycle. Progress report

    SciTech Connect

    McCluskey, R.J.

    1993-12-23

    This report describes the modifications and repairs made to the 200 ton absorption refrigeration pilot plant since April 1992, when Clarkson University assumed responsibility for it. Current operating problems and the performance of the plant, achieved to date, are detailed. Performance has been limited by small air leaks into the absorption section of the plant and by plugging in a heat exchanger which has limited the flow of purified glycol to the absorber. Nonetheless, the plant has been operated for periods of over eight hours with sustained cooling loads of 40 tons. Chilled water has been produced at a temperature as low as 38 degrees Fahrenheit. The principal leak sources have been pinpointed. Plans are described for achieving plant operation at designed levels.

  10. Effects of Interstage Cooling on Brayton Cycle Efficiency

    SciTech Connect

    Chang Oh; Robert Barner; Paul Pickard

    2006-06-01

    The US Department of Energy is investigating the use of high-temperature gas-cooled reactors (HTGR) [Oh,2005] to produce electricity and hydrogen. In anticipation of the design, development and procurement of an advanced power conversion system for HTGR, this study was initiated to identify the major design and technology options and their tradeoffs in the evaluation of power conversion system (PCS) options to support future research and procurement decisions. These PCS technology options affect cycle efficiency, capital cost, system reliability and maintainability and technical risk, and therefore the cost of electricity from Generation IV systems. In this study, we investigated the effect of interstage cooling in the PCS and present some results.

  11. Cycle reset in a melanoma cell line caused by cooling.

    PubMed

    Dewey, D L

    1987-11-01

    When cells in culture are released from G0 into cycle by diluting into fresh medium there is a delay of many hours before they re-enter the cycle and start DNA synthesis. A mouse melanoma cell line designated HP2 has been used to investigate the effects of non-standard temperatures between the time of plating and DNA synthesis. When the cells were incubated in a 5% CO2 box at 8 degrees C for periods during the G0-G1 transition there was an extra delay before the start of S, approximately equal to the time that the cells were held at 8 degrees C and independent of the time when the cold pulse was administered. When the cells were cooled to 25 degrees C the delay was longer than the time for which the cells had been kept at 25 degrees C, and this extra delay was also dependent on the point in G0-G1 when the cells were cooled, as though the cells could be reset to an earlier time by this treatment. It is suggested that a labile substance required for progression is destroyed faster than it is made at 25 degrees C but at 8 degrees C the rate of destruction is very low. Another phenomenon noted during these cooling experiments was that the peak height of the S phase profile, as measured by frequent pulse-thymidine incorporation experiments, was substantially higher for cells which had been cooled at a later stage in the G0-G1 transition, even though the overall times at 37 degrees C and at the colder temperature were identical. By varying the temperature of the cold pulse it was possible to separate the change in the peak height and the delay as separate entities. PMID:3502929

  12. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    DOE PAGESBeta

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  13. Collision--induced absorption in dense atmospheres of cool stars

    SciTech Connect

    Borysow, Aleksandra; Joergensen, Uffe Graae

    1999-04-01

    In the atmosphere of the Sun the major interaction between the matter and the radiation is through light absorption by ions (predominantly the negative ion of hydrogen atoms), neutral atoms and a small amount of polar molecules. The majority of stars in the universe are, however, cooler and denser than our Sun, and for a large fraction of these, the above absorption processes are very weak. Here, collision-induced absorption (CIA) becomes the dominant opacity source. The radiation is absorbed during very short mutual passages ('collisions') of two non-polar molecules (and/or atoms), while their electric charge distributions are temporarily distorted which gives rise to a transient dipole moment. We present here a review of the present-day knowledge about the impact of collision-induced absorption processes on the structure and the spectrum of such stars.

  14. Integrated energy, economic, and environmental assessment for the optimal solar absorption cooling and heating system

    NASA Astrophysics Data System (ADS)

    Hang, Yin

    Buildings in the United States are responsible for 41% of the primary energy use and 30% of carbon dioxide emissions. Due to mounting concerns about climate change and resource depletion, meeting building heating and cooling demand with renewable energy has attracted increasing attention in the energy system design of green buildings. One of these approaches, the solar absorption cooling and heating (SACH) technology can be a key solution to addressing the energy and environmental challenges. SACH system is an integration of solar thermal heating system and solar thermal driven absorption cooling system. So far, SACH systems still remain at the demonstration and testing stage due to not only its high cost but also complicated system characteristics. This research aims to develop a methodology to evaluate the life cycle energy, economic and environmental performance of SACH systems by high-fidelity simulations validated by experimental data. The developed methodology can be used to assist the system design. In order to achieve this goal, the study includes four objectives as follows: * Objective 1: Develop the evaluation model for the SACH system. The model includes three aspects: energy, economy, and environment from a life cycle point of view. * Objective 2: Validate the energy system model by solar experiments performance data. * Objective 3: Develop a fast and effective multi-objective optimization methodology to find the optimal system configuration which achieves the maximum system benefits on energy, economy and environment. Statistic techniques are explored to reveal the relations between the system key parameters and the three evaluation targets. The Pareto front is generated by solving this multi-objective optimization problem. * Objective 4: Apply the developed assessment methodology to different building types and locations. Furthermore, this study considered the influence of the input uncertainties on the overall system performance. The sensitivity

  15. Advanced heat pump cycle for district heating and cooling systems

    SciTech Connect

    Radermacher, R.

    1991-07-01

    A bread board heat pump was designed and built to test the performance of a vapor compression heat pump with two stage ammonia-water solution circuits. The design was updated based on the experience gained with the single stage version of this heat pump. A major improvement was obtained by eliminating the rectifier. The new scheme was first investigated by computer simulation and then incorporated in the experimental setup. Water balance in the high and low temperature circuits is now maintained by bleeding up to 2.5% of the weak solution flow from one solution circuit to the other. The advantages of this scheme are reduced first cost, simplified design and control, 20--30% improvement in cooling coefficient of performance and 10--15% increase in cooling capacity as compared to the cycle with a rectifier. Coefficients of performance in the range of 0.84 to 1.03 were obtained experimentally for a temperature lift of 100-K. The pressure ratios encountered were in the range of 7.6 to 9.9, which are 35 to 50% of the pressure ratio expected for a conventional heat pump. Thus the results demonstrate that high temperature lifts can be achieved at pressure ratios which are less than half as large as for conventional systems. The cooling capacities were in the range of 2.79 to 4.21 kW. 13 refs., 5 figs., 2 tabs.

  16. Improvement of the COP of the LiBr-Water Double-Effect Absorption Cycles

    NASA Astrophysics Data System (ADS)

    Shitara, Atsushi

    Prevention of the global warming has called for a great necessity for energy saving. This applies to the improvement of the COP of absorption chiller-heaters. We started the development of the high efficiency gas-fired double-effect absorption chiller-heater using LiBr-H2O to achieve target performance in short or middle term. To maintain marketability, the volume of the high efficiency machine has been set below the equal to the conventional machine. The absorption cycle technology for improving the COP and the element technology for downsizing the machine is necessary in this development. In this study, the former is investigated. In this report, first of all the target performance has been set at cooling COP of 1.35(on HHV), which is 0.35 higher than the COP of 1.0 for conventional machines in the market. This COP of 1.35 is practically close to the maximum limit achievable by double-effect absorption chiller-heater. Next, the design condition of each element to achieve the target performance and the effect of each mean to improve the COP are investigated. Moreover, as a result of comparing the various flows(series, parallel, reverse)to which the each mean is applied, it has been found the optimum cycle is the parallel flow.

  17. Performance Prediction Method of CO2 Cycle for Air Cooling

    NASA Astrophysics Data System (ADS)

    Koyama, Shigeru; Xue, Jun; Kuwahara, Ken

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

  18. Near-UV absorption in very cool DA white dwarfs

    SciTech Connect

    Saumon, D.; Holberg, J. B.; Kowalski, P. M. E-mail: holberg@argus.lpl.arizona.edu

    2014-07-20

    The atmospheres of very cool, hydrogen-rich white dwarfs (WDs) (T{sub eff} < 6000 K) are challenging to model because of the increased complexity of the equation of state, chemical equilibrium, and opacity sources in a low-temperature, weakly ionized dense gas. In particular, many models that assume relatively simple models for the broadening of atomic levels and mostly ideal gas physics overestimate the flux in the blue part of their spectra. A solution to this problem that has met with some success is that additional opacity at short wavelengths comes for the extreme broadening of the Lyman α line of atomic H by collisions primarily with H{sub 2}. For the purpose of validating this model more rigorously, we acquired Hubble Space Telescope STIS spectra of eight very cool WDs (five DA and three DC stars). Combined with their known parallaxes, BVRIJHK, and Spitzer IRAC photometry, we analyze their entire spectral energy distribution (from 0.24 to 9.3 μm) with a large grid of model atmospheres and synthetic spectra. We find that the red wing of the Lyman α line reproduces the rapidly decreasing near-UV flux of these very cool stars very well. We determine better constrained values of T{sub eff} and gravity as well as upper limits to the helium abundance in their atmospheres.

  19. Development and proof-testing of advanced absorption refrigeration cycle concepts

    SciTech Connect

    Modahl, R.J.; Hayes, F.C. . Applied Unitary/Refrigeration Systems Div.)

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  20. Water-lithium bromide double-effect absorption cooling analysis. Final report

    SciTech Connect

    Vliet, G.C.; Lawson, M.B.; Lithgow, R.A.

    1980-12-01

    This investigation involved the development of a numerical model for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine, and the use of the model to determine the effect of the various design and input variables on the absorption unit performance. The performance parameters considered were coefficient of performance and cooling capacity. The sensitivity analysis was performed by selecting a nominal condition and determining performance sensitivity for each variable with others held constant. The variables considered in the study include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods. The performance sensitivity study indicated in particular that the distribution of heat exchanger area among the various (seven) heat exchange components is a very important design consideration. Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity. The model was used to predict the performance of the Trane absorption unit with fairly good accuracy. The dynamic model should be valuable as a design tool for developing new absorption machines or modifying current machines to make them optimal based on current and future energy costs.

  1. Analysis of a solar heat pipe heating and absorption cooling system

    NASA Astrophysics Data System (ADS)

    Munje, S. R.

    A new concept which combines a flat-plate heat-pipe solar collector for daytime solar water heating by evaporation of a refrigerant and night-time water chilling by absorption refrigeration was analyzed. A comprehensive survey of literature was completed to establish the existing state of knowledge on intermittent absorption refrigeration, flat-plate solar heat collectors and night sky radiation cooling. The literature survey showed that the idea of using a passive device such as a heat pipe with the absorption refrigeration principle for both heating and cooling is relatively new. A mathematical model for the heat-pipe flat-plate collector and the absorption refrigeration process was developed. A cost-effectiveness study was also carried out to find the optimum thickness of the collector plate. The optimum plate thickness was used in the parametric study of the system.

  2. Experimental investigation of an ammonia-based combined power and cooling cycle

    NASA Astrophysics Data System (ADS)

    Tamm, Gunnar Olavi

    A novel ammonia-water thermodynamic cycle, capable of producing both power and refrigeration, was proposed by D. Yogi Goswami. The binary mixture exhibits variable boiling temperatures during the boiling process, which leads to a good thermal match between the heating fluid and working fluid for efficient heat source utilization. The cycle can be driven by low temperature sources such as solar, geothermal, and waste heat from a conventional power cycle, reducing the reliance on high temperature sources such as fossil fuels. A theoretical simulation of the cycle at heat source temperatures obtainable from low and mid temperature solar collectors showed that the ideal cycle could produce power and refrigeration at a maximum exergy efficiency, defined as the ratio of the net work and refrigeration output to the change in availability of the heat source, of over 60%. The exergy efficiency is a useful measure of the cycle's performance as it compares the effectiveness of different cycles in harnessing the same source. An experimental system was constructed to demonstrate the feasibility of the cycle and to compare the experimental results with the theoretical simulations. In this first phase of experimentation, the turbine expansion was simulated with a throttling valve and a heat exchanger. Results showed that the vapor generation and absorption condensation processes work experimentally. The potential for combined turbine work and refrigeration output was evidenced in operating the system. Analysis of losses led to modifications in the system design, which were implemented to yield improvements in heat exchange, vapor generation, pump performance and overall stability. The research that has been conducted verifies the potential of the power and cooling cycle as an alternative to using conventional fossil fuel technologies. The research that continues is to further demonstrate the concept and direct it towards industry. On the large scale, the cycle can be used for

  3. Thermal design of lithium bromide-water solution vapor absorption cooling system for indirect evaporative cooling for IT pod

    NASA Astrophysics Data System (ADS)

    Sawant, Digvijay Ramkrishna

    Nowadays with increase use of internet, mobile there is increase in heat which ultimately increases the efficient cooling system of server room or IT POD. Use of traditional ways of cooling system has ultimately increased CO2 emission and depletion of CFC's are serious environmental issues which led scientific people to improve cooling techniques and eliminate use of CFC's. To reduce dependency on fossil fuels and 4environmental friendly system needed to be design. For being utilizing low grade energy source such as solar collector and reducing dependency on fossil fuel vapour absorption cooling system has shown a great driving force in today's refrigeration systems. This LiBr-water aabsorption cooling consists of five heat exchanger namely: Evaporator, Absorber, Solution Heat Exchanger, Generator, Condenser. The thermal design was done for a load of 23 kW and the procedure was described in the thesis. There are 120 servers in the IT POD emitting 196 W of heat each on full load and some of the heat was generated by the computer placed inside the IT POD. A detailed procedure has been discussed. A excel spreadsheet was to prepared with varying tube sizes to see the effect on flows and ultimately overall heat transfer coefficient.

  4. Evaluation of absorption cycle for space station environmental control system application

    NASA Technical Reports Server (NTRS)

    Sims, W. H.; Oneill, M. J.; Reid, H. C.; Bisenius, P. M.

    1972-01-01

    The study to evaluate an absorption cycle refrigeration system to provide environmental control for the space stations is reported. A zero-gravity liquid/vapor separator was designed and tested. The results were used to design a light-weight, efficient generator for the absorption refrigeration system. It is concluded that absorption cycle refrigeration is feasible for providing space station environmental control.

  5. Properties of the Carrol system and a machine design for solar-powered, air cooled, absorption space cooling

    NASA Astrophysics Data System (ADS)

    1981-05-01

    The name Carrol was selected as a convenient shorthand designation for a prime candidate chemical system comprising ethylene glycol-lithium bromide as an absorbent mixture with water as a refrigerant. The instrumentation, methods of handling data and numerical results from a systematic determination of Carrol property data required to design an air cooled absorption machine based on this chemical system are described. These data include saturation temperature, relative enthalpy, density, specific heat capacity, thermal conductivity, viscosity and absorber film heat transfer coefficient as functions of solution temperature and Carrol concentration over applicable ranges. For each of the major components of the absorption chiller, i.e., generator, chiller, absorber, condenser, heat exchanger, purge and controls, the report contains an assembly drawing and the principal operating characteristics of that component.

  6. Recent advances in SRS on hydrogen isotope separation using thermal cycling absorption process

    SciTech Connect

    Xiao, X.; Kit Heung, L.; Sessions, H.T.

    2015-03-15

    TCAP (Thermal Cycling Absorption Process) is a gas chromatograph in principle using palladium in the column packing, but it is unique in the fact that the carrier gas, hydrogen, is being isotopically separated and the system is operated in a semi-continuous manner. TCAP units are used to purify tritium. The recent TCAP advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10 of the current production system's footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects.

  7. Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat

    SciTech Connect

    2010-09-01

    BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

  8. Investigation of Absorption Cooling Application Powered by Solar Energy in the South Coast Region of Turkey

    NASA Astrophysics Data System (ADS)

    Babayigit, O.; Aksoy, M. H.; Ozgoren, M.; Solmaz, O.

    2013-04-01

    In this study, an absorption system using ammonia-water (NH3-H2O) solution has been theoretically examined in order to meet the cooling need of a detached building having 150 m2 floor area for Antalya, Mersin and Mugla provinces in Turkey. Hourly dynamic cooling load capacities of the building were determined by using Radiant Time Series (RTS) method in the chosen cities. For the analysis, hourly average meteorological data such as atmospheric air temperature and solar radiation belonging to the years 1998-2008 are used for performance prediction of the proposed system. Thermodynamic relations for each component of absorption cooling system is explained and coefficients of performance of the system are calculated. The maximum daily total radiation data were calculated as 7173 W/m2day on July 15, 7277 W/m2 day on July 19 and 7231 W/m2day on July 19 for Mersin, Antalya and Mugla, respectively on the 23° toward to south oriented panels from horizontal surface. The generator operating temperatures are considered between 90-130°C and the best result for 110°C is found the optimum degree for maximum coefficient of performance (COP) values at the highest solar radiation occurred time during the considered days for each province. The COP values varies between 0.521 and 0.530 for the provinces. In addition, absorber and condenser capacities and thermal efficiency for the absorption cooling system were calculated. The necessary evacuated tube collector area for the different provinces were found in the range of 45 m2 to 47 m2. It is shown that although the initial investment cost is higher for the proposed absorption cooling system, it is economically feasible because of its lower annual operation costs and can successfully be operated for the considered provinces.

  9. Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production

    NASA Astrophysics Data System (ADS)

    Al-Sulaiman, Fahad A.; Dincer, Ibrahim; Hamdullahpur, Feridun

    The study examines a novel system that combined a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC) for cooling, heating and power production (trigeneration) through exergy analysis. The system consists of an SOFC, an ORC, a heat exchanger and a single-effect absorption chiller. The system is modeled to produce a net electricity of around 500 kW. The study reveals that there is 3-25% gain on exergy efficiency when trigeneration is used compared with the power cycle only. Also, the study shows that as the current density of the SOFC increases, the exergy efficiencies of power cycle, cooling cogeneration, heating cogeneration and trigeneration decreases. In addition, it was shown that the effect of changing the turbine inlet pressure and ORC pump inlet temperature are insignificant on the exergy efficiencies of the power cycle, cooling cogeneration, heating cogeneration and trigeneration. Also, the study reveals that the significant sources of exergy destruction are the ORC evaporator, air heat exchanger at the SOFC inlet and heating process heat exchanger.

  10. Absorption-line profiles in a companion spectrum of a mass-losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1992-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10 (exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  11. Absorption line profiles in a companion spectrum of a mass losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1990-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  12. Parallel LC circuit model for multi-band absorption and preliminary design of radiative cooling.

    PubMed

    Feng, Rui; Qiu, Jun; Liu, Linhua; Ding, Weiqiang; Chen, Lixue

    2014-12-15

    We perform a comprehensive analysis of multi-band absorption by exciting magnetic polaritons in the infrared region. According to the independent properties of the magnetic polaritons, we propose a parallel inductance and capacitance(PLC) circuit model to explain and predict the multi-band resonant absorption peaks, which is fully validated by using the multi-sized structure with identical dielectric spacing layer and the multilayer structure with the same strip width. More importantly, we present the application of the PLC circuit model to preliminarily design a radiative cooling structure realized by merging several close peaks together. This omnidirectional and polarization insensitive structure is a good candidate for radiative cooling application. PMID:25607485

  13. Optical and ultraviolet absorption studies of cool gas in the Milky Way halo

    NASA Technical Reports Server (NTRS)

    Danly, L.

    1990-01-01

    This paper focuses on the contributions from absorption techniques to the knowledge of halo gas with temperatures below 10 to the 5th K. The results from observations of the neutral and singly ionized species on the nature of cool gas in the halo, its structure and its kinematics are presented. An overview of past and optical and ultraviolet observational studies of halo gas is included.

  14. Discovery of spontaneous deformation of Pd metal during hydrogen absorption/desorption cycles

    PubMed Central

    Yamazaki, Toshimitsu; Sato, Masaharu; Itoh, Satoshi

    2009-01-01

    A drastic deformation was observed in Pd metal of various shapes after hydrogen absorption and desorption cycles at 150 °C at a gas pressure of 1–5 MPa. All of the phenomena observed indicate that some strong internal force is induced spontaneously during hydrogen absorption/desorption cycles to produce a collective deformation so as to minimize the surface. PMID:19444010

  15. Small quantum absorption refrigerator in the transient regime: Time scales, enhanced cooling, and entanglement.

    PubMed

    Brask, Jonatan Bohr; Brunner, Nicolas

    2015-12-01

    A small quantum absorption refrigerator, consisting of three qubits, is discussed in the transient regime. We discuss time scales for coherent dynamics, damping, and approach to the steady state, and we study cooling and entanglement. We observe that cooling can be enhanced in the transient regime, in the sense that lower temperatures can be achieved compared to the steady-state regime. This is a consequence of coherent dynamics but can occur even when this dynamics is strongly damped by the dissipative thermal environment, and we note that precise control over couplings or timing is not needed to achieve enhanced cooling. We also show that the amount of entanglement present in the refrigerator can be much larger in the transient regime compared to the steady state. These results are of relevance to future implementations of quantum thermal machines. PMID:26764626

  16. Small quantum absorption refrigerator in the transient regime: Time scales, enhanced cooling, and entanglement

    NASA Astrophysics Data System (ADS)

    Brask, Jonatan Bohr; Brunner, Nicolas

    2015-12-01

    A small quantum absorption refrigerator, consisting of three qubits, is discussed in the transient regime. We discuss time scales for coherent dynamics, damping, and approach to the steady state, and we study cooling and entanglement. We observe that cooling can be enhanced in the transient regime, in the sense that lower temperatures can be achieved compared to the steady-state regime. This is a consequence of coherent dynamics but can occur even when this dynamics is strongly damped by the dissipative thermal environment, and we note that precise control over couplings or timing is not needed to achieve enhanced cooling. We also show that the amount of entanglement present in the refrigerator can be much larger in the transient regime compared to the steady state. These results are of relevance to future implementations of quantum thermal machines.

  17. SIMPLE MODELS OF METAL-LINE ABSORPTION AND EMISSION FROM COOL GAS OUTFLOWS

    SciTech Connect

    Prochaska, J. Xavier; Rubin, Kate

    2011-06-10

    We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We implement Monte Carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate one-dimensional spectra and two-dimensional spectral images. We focus on the Mg II {lambda}{lambda}2796, 2803 doublet and Fe II UV1 multiplet at {lambda} {approx} 2600 A, but the results are applicable to other transitions that trace outflows (e.g., Na I, H I Ly{alpha}, Si II). By design, the resonance transitions show blueshifted absorption but one also predicts strong resonance and fine-structure line emission at roughly the systemic velocity. This line-emission 'fills in' the absorption, reducing the equivalent width by up to 50%, shifting the absorption-line centroid by tens of km s{sup -1}, and reducing the effective opacity near systemic. Analysis of cool gas outflows that ignores this line emission may incorrectly infer that the gas is partially covered, measure a significantly lower peak optical depth, and/or conclude that gas at systemic velocity is absent (e.g., an interstellar or slowly infalling component). Because the Fe II lines are connected by optically thin transitions to fine-structure levels, their profiles more closely reproduce the intrinsic opacity of the wind. Together these results naturally explain the absorption and emission-line characteristics observed for star-forming galaxies at z < 1. We also study a scenario promoted to describe the outflows of z {approx} 3 Lyman break galaxies and find profiles inconsistent with the observations due to scattered photon emission. Although line emission complicates the analysis of absorption-line profiles, the surface brightness profiles offer a unique means of assessing the morphology and size of galactic-scale winds. Furthermore, the kinematics and line ratios offer powerful diagnostics of outflows, motivating deep

  18. Simple Models of Metal-line Absorption and Emission from Cool Gas Outflows

    NASA Astrophysics Data System (ADS)

    Prochaska, J. Xavier; Kasen, Daniel; Rubin, Kate

    2011-06-01

    We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We implement Monte Carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate one-dimensional spectra and two-dimensional spectral images. We focus on the Mg II λλ2796, 2803 doublet and Fe II UV1 multiplet at λ ≈ 2600 Å, but the results are applicable to other transitions that trace outflows (e.g., Na I, H I Lyα, Si II). By design, the resonance transitions show blueshifted absorption but one also predicts strong resonance and fine-structure line emission at roughly the systemic velocity. This line-emission "fills in" the absorption, reducing the equivalent width by up to 50%, shifting the absorption-line centroid by tens of km s-1, and reducing the effective opacity near systemic. Analysis of cool gas outflows that ignores this line emission may incorrectly infer that the gas is partially covered, measure a significantly lower peak optical depth, and/or conclude that gas at systemic velocity is absent (e.g., an interstellar or slowly infalling component). Because the Fe II lines are connected by optically thin transitions to fine-structure levels, their profiles more closely reproduce the intrinsic opacity of the wind. Together these results naturally explain the absorption and emission-line characteristics observed for star-forming galaxies at z < 1. We also study a scenario promoted to describe the outflows of z ~ 3 Lyman break galaxies and find profiles inconsistent with the observations due to scattered photon emission. Although line emission complicates the analysis of absorption-line profiles, the surface brightness profiles offer a unique means of assessing the morphology and size of galactic-scale winds. Furthermore, the kinematics and line ratios offer powerful diagnostics of outflows, motivating deep, spatially extended spectroscopic

  19. System and method for regulating EGR cooling using a rankine cycle

    DOEpatents

    Ernst, Timothy C.; Morris, Dave

    2015-12-22

    This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

  20. Passive vibration isolation for SITELLE's closed cycle cooled cryostats

    NASA Astrophysics Data System (ADS)

    Baril, Marc; Benedict, Tom; Barrick, Gregory; Ho, Kevin

    2012-09-01

    The SITELLE Imaging Fourier Transform Spectrometer system being developed by l'Université Laval at ABB-Bomem will require two identical CCD detector systems. Our requirements for the cryogenic system for these cameras are: cooling to below 190 K, extremely low vibrational input from the cryogenic system (<1 mg RMS from 0-2 kHz), hands-off operation over long periods of time and low original capital outlay and continued operation cost. These constraints drove towards the selection of a Polycold PCC cooled system which exhibits relatively low vibrational noise and can efficiently achieve the required cooling power in our target temperature range. This paper will present work performed to passively mitigate high frequency vibrations imparted by the Polycold PCC cryo-head on the detector cryostat.

  1. Infrared absorption of dense helium and its importance in the atmospheres of cool white dwarfs

    NASA Astrophysics Data System (ADS)

    Kowalski, Piotr M.

    2014-06-01

    Aims: Hydrogen-deficient white dwarfs are characterized by very dense, fluid-like atmospheres of complex physics and chemistry that are still poorly understood. The incomplete description of these atmospheres by the models results in serious problems with the description of spectra of these stars and subsequent difficulties in derivation of their surface parameters. Here, we address the problem of infrared (IR) opacities in the atmospheres of cool white dwarfs by direct ab initio simulations of IR absorption of dense helium. Methods: We applied state-of-the-art density functional theory-based quantum molecular dynamics simulations to obtain the time evolution of the induced dipole moment. The IR absorption coefficients were obtained by the Fourier transform of the dipole moment time autocorrelation function. Results: We found that a dipole moment is induced due to three- and more-body simultaneous collisions between helium atoms in highly compressed helium. This results in a significant IR absorption that is directly proportional to ρHe3, where ρHe is the density of helium. To our knowledge, this absorption mechanism has never been measured or computed before and is therefore not accounted for in the current atmosphere models. It should dominate the other collisionally induced absorptions (CIA), arising from H-He and H2-He pair collisions, and therefore shape the IR spectra of helium-dominated and pure helium atmosphere cool white dwarfs for He/H > 104. Conclusions: Our work shows that there exists an unaccounted IR absorption mechanism arising from the multi-collisions between He atoms in the helium-rich atmospheres of cool white dwarfs, including pure helium atmospheres. This absorption may be responsible for a yet unexplained frequency dependence of near- and mid-IR spectra of helium-rich stars. The opacity table is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  2. Measured performance of a 3-ton LiBr absorption water chiller and its effect on cooling system operation

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1976-01-01

    A 3-ton lithium bromide absorption water chiller was tested for a number of conditions involving hot-water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It is concluded that a 3-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

  3. Measured performance of a 3 ton LiBr absorption water chiller and its effect on cooling system operation

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1976-01-01

    A three ton lithium bromide absorption water chiller was tested for a number of conditions involving hot water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It was concluded that a three-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

  4. The influence of external cooling system on the performance of supercritical steam turbine cycles

    NASA Astrophysics Data System (ADS)

    Kosman, Wojciech

    2010-09-01

    The problem presented in this paper refers to the concepts applied to the design of supercritical steam turbines. The issue under the investigation is the presence of a cooling system. Cooling systems aim to protect the main components of the turbines against overheating. However the cooling flows mix with the main flow and modify the expansion line in the steam path. This affects the expansion process in the turbine and changes the performance when compared to the uncooled turbine. The analysis described here investigates the range of the influence of the cooling system on the turbine cycle. This influence is measured mainly through the change of the power generation efficiency. The paper explains the approach towards the assessment of the cooling effects and presents results of the modeling for three supercritical steam cycles.

  5. A combined gas cooled nuclear reactor and fuel cell cycle

    NASA Astrophysics Data System (ADS)

    Palmer, David J.

    Rising oil costs, global warming, national security concerns, economic concerns and escalating energy demands are forcing the engineering communities to explore methods to address these concerns. It is the intention of this thesis to offer a proposal for a novel design of a combined cycle, an advanced nuclear helium reactor/solid oxide fuel cell (SOFC) plant that will help to mitigate some of the above concerns. Moreover, the adoption of this proposal may help to reinvigorate the Nuclear Power industry while providing a practical method to foster the development of a hydrogen economy. Specifically, this thesis concentrates on the importance of the U.S. Nuclear Navy adopting this novel design for its nuclear electric vessels of the future with discussion on efficiency and thermodynamic performance characteristics related to the combined cycle. Thus, the goals and objectives are to develop an innovative combined cycle that provides a solution to the stated concerns and show that it provides superior performance. In order to show performance, it is necessary to develop a rigorous thermodynamic model and computer program to analyze the SOFC in relation with the overall cycle. A large increase in efficiency over the conventional pressurized water reactor cycle is realized. Both sides of the cycle achieve higher efficiencies at partial loads which is extremely important as most naval vessels operate at partial loads as well as the fact that traditional gas turbines operating alone have poor performance at reduced speeds. Furthermore, each side of the cycle provides important benefits to the other side. The high temperature exhaust from the overall exothermic reaction of the fuel cell provides heat for the reheater allowing for an overall increase in power on the nuclear side of the cycle. Likewise, the high temperature helium exiting the nuclear reactor provides a controllable method to stabilize the fuel cell at an optimal temperature band even during transients helping

  6. Improving the performance of ammonia-water absorption cycles using salt additives and membranes

    SciTech Connect

    Ibrahim, O.M.; Barnett, S.M.; Balamuru, V.G.

    1997-12-31

    This paper proposes a new design of an ammonia-water absorption refrigeration cycle for low-temperature heat sources such as solar energy and waste heat. The proposed cycle uses a salt additive to shift the chemical equilibrium toward more effective separation of ammonia molecules from aqueous solution (i.e., salting out). Since salt additives can affect all aspects of the absorption cycle, membranes have been chosen to control the flow of ions in the cycle and limit their effects to the generation side. This paper describes an absorption cycle that uses membrane separation processes, such as reverse osmosis, dialysis, and electrodialysis. To optimize the performance of the cycle, however, the membranes and salts must be carefully chosen.

  7. Development and proof-testing of advanced absorption refrigeration cycle concepts. Report on Phases 1 and 1A

    SciTech Connect

    Modahl, R.J.; Hayes, F.C.

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  8. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, A.A.

    1985-07-02

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs. 3 figs.

  9. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, Anthony A.

    1985-01-01

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

  10. Cycle simulation of the low-temperature triple-effect absorption chiller with vapor compression unit

    SciTech Connect

    Kim, J.S.; Lee, H.

    1999-07-01

    The construction of a triple-effect absorption chiller machine using the lithium bromide-water solution as a working fluid is strongly limited by corrosion problems caused by the high generator temperature. In this work, three new cycles having the additional vapor compression units were suggested in order to lower the generator temperature of a triple-effect absorption chiller. Each new cycle has one compressor located at the different position which was used to elevate the pressure of the refrigerant vapor. Computer simulations were carried out in order to examine both the basic triple-effect cycle and three new cycles. All types of triple-effect absorption chiller cycles were found to be able to lower the temperature of high-temperature generator to the more favorable operation range. The COPs of three cycles calculated by considering the additional compressor works showed a small level of decrease or increase compared with that of the basic triple-effect cycle. Consequently, a low-temperature triple-effect absorption chiller can be possibly constructed by adapting one of three new cycles. A great advantage of these new cycles over the basic one is that the conventionally used lithium bromide-water solution can be successfully used as a working fluid without the danger of corrosion.

  11. Parametric Investigation of Brayton Cycle for High Temperature Gas-Cooled Reactor

    SciTech Connect

    Chang Oh

    2004-07-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is investigating a Brayton cycle efficiency improvement on a high temperature gas-cooled reactor (HTGR) as part of Generation-IV nuclear engineering research initiative. In this project, we are investigating helium Brayton cycles for the secondary side of an indirect energy conversion system. Ultimately we will investigate the improvement of the Brayton cycle using other fluids, such as supercritical carbon dioxide. Prior to the cycle improvement study, we established a number of baseline cases for the helium indirect Brayton cycle. These cases look at both single-shaft and multiple-shaft turbomachinary. The baseline cases are based on a 250 MW thermal pebble bed HTGR. The results from this study are applicable to other reactor concepts such as a very high temperature gas-cooled reactor (VHTR), fast gas-cooled reactor (FGR), supercritical water reactor (SWR), and others. In this study, we are using the HYSYS computer code for optimization of the helium Brayton cycle. Besides the HYSYS process optimization, we performed parametric study to see the effect of important parameters on the cycle efficiency. For these parametric calculations, we use a cycle efficiency model that was developed based on the Visual Basic computer language. As a part of this study we are currently investigated single-shaft vs. multiple shaft arrangement for cycle efficiency and comparison, which will be published in the next paper.The ultimate goal of this study is to use supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency to values great than that of the helium Brayton cycle. This paper includes preliminary calculations of the steady state overall Brayton cycle efficiency based on the pebble bed reactor reference design (helium used as the working fluid) and compares those results with an initial calculation of a CO2 Brayton cycle.

  12. Polarization reversal induced by heating-cooling cycles in MgO doped lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Shur, V. Ya.; Mingaliev, E. A.; Lebedev, V. A.; Kuznetsov, D. K.; Fursov, D. V.

    2013-05-01

    Polarization reversal during heating-cooling cycles was investigated in MgO doped lithium niobate (MgO:LN) crystal using piezoresponse force microscopy. The essential dependence of the domain structure evolution scenario on the maximal temperature in the cycle has been revealed experimentally. It has been shown that the heating of the engineered domain matrix from room temperature to 85 °C leads to light size reduction of the isolated domains at the matrix edges, whereas the heating to 170 °C leads to essential reduction of the domain size. The opposite strong effect of the domain formation and growth during cooling after pulse heating have been revealed in single domain MgO:LN. The simulation of the time dependence of the pyroelectric field during heating-cooling cycle allowed to reveal the temperature hysteresis and to explain all observed effects taking into account the temperature dependence of the bulk conductivity.

  13. Effects of geometric configuration on the cooling performance of Vuilleumier cycle heat pump

    SciTech Connect

    Lee, G.T.; Kang, B.H.; Yoo, H.

    1996-12-31

    An experimental study has been carried out to investigate the effects of the combination of the different wire mesh number in regenerator, and the tube number in cooler on the cooling performance of a Vuilleumier cycle heat pump. A wide range of charging pressures, heater tube temperatures and revolution speeds are also considered. The results indicate that the cooling performance is improved with the proper combination of different wire meshes in the cold regenerator. More tubes in a cooler are desirable for better cooling performance. It is also found that the cooling capacity is enhanced, whereas COP is reduced, with an increase in the heater tube temperature and revolution speed. Both the cooling capacity and COP are increased with a higher charger pressure.

  14. New cooling system chemistry provides 45% cost savings through high cycle operation

    SciTech Connect

    Tylec, M.; Janeczko, J.; Tari, K.

    1998-07-01

    Operating cost minimization is an everyday goal for the Power Generation Industry. The cost-effective treatment of open recirculating cooling systems for corrosion, mineral scale, fouling, and microbiological growth is critical to ensure optimal generation of power. Capitalizing on an advancement in alkaline cooling water technology enabled a northeastern cogeneration plant to reduce water consumption, discharge costs, and treatment costs. This paper discusses the conversion from a conventional phosphonate technology to Continuum{reg{underscore}sign} AEC, a revolutionary cooling water treatment program. It details the increased cycles of concentration, improved treatment performance, and reduced overall operating costs provided by the new treatment program.

  15. Open cycle liquid desiccant dehumidifier and hybrid solar/electric absorption refrigeration system. Annual report, January 1993--December 1993. Calendar year 1993

    SciTech Connect

    Nimmo, B.G.; Thornbloom, M.D.

    1995-04-01

    This annual report presents work performed during calendar year 1993 by the Florida Solar Energy Center under contract to the US Department of Energy. Two distinctively different solar powered indoor climate control systems were analyzed: the open cycle liquid desiccant dehumidifier, and an improved efficiency absorption system which may be fired by flat plate solar collectors. Both tasks represent new directions relative to prior FSEC research in Solar Cooling and Dehumidification.

  16. Self operating absorption cooling system using solar energy: Small power experimental plant

    NASA Astrophysics Data System (ADS)

    Velluet, P.; Dehausse, R.

    This study deals with a solar system for refrigeration specially designed for remote areas conditions. So, it must be very simple and reliable, and in addition it must be also mechanically self-operating. The thermodynamic cycle used is an ammonia-water absorption one. It consumes only thermal energy, which is easily and cheaply converted directly from solar radiation. In order to make a self-operating system, an engine is located between the boiler (at high pressure) and the absorber (at low pressure). It expands ammonia vapor and produces mechanical energy to run the solution pump.

  17. The Hopf's limiting cycle -- A method to measure the electron cooling force

    SciTech Connect

    King-Yuen Ng

    2002-09-30

    The longitudinal phase space structure of protons in the presence of an electron drag force is studied. Depending on the relative difference in average proton velocity and electron velocity, the fixed point near the center of the phase space can be stable or unstable. When it is unstable, a stable Hopf's limit cycle exists. By measuring the appearance and size of the Hopf's limit cycle, the electron cooling force can be deduced.

  18. Coherence-assisted single-shot cooling by quantum absorption refrigerators

    NASA Astrophysics Data System (ADS)

    Mitchison, Mark T.; Woods, Mischa P.; Prior, Javier; Huber, Marcus

    2015-11-01

    The extension of thermodynamics into the quantum regime has received much attention in recent years. A primary objective of current research is to find thermodynamic tasks which can be enhanced by quantum mechanical effects. With this goal in mind, we explore the finite-time dynamics of absorption refrigerators composed of three quantum bits (qubits). The aim of this finite-time cooling is to reach low temperatures as fast as possible and subsequently extract the cold particle to exploit it for information processing purposes. We show that the coherent oscillations inherent to quantum dynamics can be harnessed to reach temperatures that are colder than the steady state in orders of magnitude less time, thereby providing a fast source of low-entropy qubits. This effect demonstrates that quantum thermal machines can surpass classical ones, reminiscent of quantum advantages in other fields, and is applicable to a broad range of technologically important scenarios.

  19. The performance of a solar-regenerated open-cycle desiccant bed grain cooling system

    SciTech Connect

    Ismail, M.Z.; Angus, D.E. ); Thorpe, G.R. )

    1991-01-01

    The cooling of stored food grains suppresses the growth of populations of insect pests, inhibits spoilage by fungi and helps to preserve grain quality. In temperate and subtropical climates, grains may be effectively cooled by ventilating them with ambient air. In tropical climates, the enthalpy of the air must be reduced before it can be used for cooling grain. One method of achieving this is to isothermally reduce the humidity of the air. This paper describes experiments carried out on a simple-to-build solar-regenerated open-cycle grain cooling system. The device consists of a 5.85 m{sup 2} collector coupled with two beds of silica gel. Results from a series of experiments suggest that the device may be used to cool up to 200 tons of grain. The electrical power consumption of the device is of the order of 0.3 watt per ton of grain cooled, and the total electrical energy consumption is of the order of 0.7 kWh per ton of grain stored for a six-month period. The effectiveness of the device is a function of air flow rate and the enthalpy of ambient air, and results presented in this paper suggest that the solar cooling device is particularly effective in tropical climates.

  20. Open cycle He-3 cooling to 0.18 K for space operation

    NASA Astrophysics Data System (ADS)

    Frank, D.; Nast, T. C.

    It is pointed out that many space instruments will require very low cryogenic temperatures to perform satisfactorily. Thus, instruments for telescopes such as the Space Infrared Telescope Facility (SIRTF) will require a cooler to provide approximately 50 microwatts total cooling power at temperatures in the range from 0.1 to 0.3 K. The present paper is concerned with a long life open-cycle He-3 cooler which provides low cooling (50 microwatts) to a temperature as low as 0.18 K on the basis of a process involving the continuous evaporation of liquid He-3 and the loss of vapor through a vent tube. Attention is given to an open cycle He-3 cooler used in conjunction with a telescope which utilizes superfluid He-4, the venting characteristics, on-orbit liquid retention, and closed-cycle refrigeration below 1 K.

  1. A small helium liquifier which provides continuous cooling based on cycled isentropic expansion

    NASA Technical Reports Server (NTRS)

    Winter, C.; Gygax, S.; Myrtle, K.; Barton, R.

    1985-01-01

    This simple cryocooler provides a small reservoir of liquid helium at a stable temperature of 4.2K. It uses a novel adaptation of the Simon expansion cryocooler to provide continuous cooling. Operation is in a four stage cycle: (1) A closed vessel of helium under high pressure is cooled to 12K using a conventional Gifford-McMahon closed-cycle cryocooler. (2) The pressure is released adiabatically providing cooling to 4.2K. (3) Liquid helium is collected in a second, well insulated, vessel. (4) The first vessel is repressurized. The cycle time is 15-30 minutes. In this manner, a pool of liquid helium is continuously maintained in the second vessel, with a temperature stability of 0.03 degrees. The continuous cooling power available is 3mW. This design provides simplicity and reliability through the absence of any orifices or moving parts at cryogenic temperatures except for the conventional Gifford-McMahon cryocooler.

  2. Thermodynamic modelling of a double-effect LiBr-H2O absorption refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Iranmanesh, A.; Mehrabian, M. A.

    2012-12-01

    The goal of this paper is to estimate the conductance of components required to achieve the approach temperatures, and gain insights into a double-effect absorption chiller using LiBr-H2O solution as the working fluid. An in-house computer program is developed to simulate the cycle. Conductance of all components is evaluated based on the approach temperatures assumed as input parameters. The effect of input data on the cycle performance and the exergetic efficiency are investigated.

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

    NASA Astrophysics Data System (ADS)

    Bauthier, J.

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

  4. The absorption chiller in large scale solar pond cooling design with condenser heat rejection in the upper convecting zone

    SciTech Connect

    Tsilingiris, P.T. )

    1992-07-01

    The possibility of using solar ponds as low-cost solar collectors combined with commercial absorption chillers in large scale solar cooling design is investigated. The analysis is based on the combination of a steady-state solar pond mathematical model with the operational characteristics of a commercial absorption chiller, assuming condenser heat rejection in the upper convecting zone (U.C.Z.). The numerical solution of the nonlinear equations involved leads to results which relate the chiller capacity with pond design and environmental parameters, which are also employed for the investigation of the optimum pond size for a minimum capital cost. The derived cost per cooling kW for a 350 kW chiller ranges from about 300 to 500 $/kW cooling. This is almost an order of magnitude lower than using a solar collector field of evacuated tube type.

  5. Development of a Water Based, Critical Flow, Non-Vapor Compression cooling Cycle

    SciTech Connect

    Hosni, Mohammad H.

    2014-03-30

    Expansion of a high-pressure liquid refrigerant through the use of a thermostatic expansion valve or other device is commonplace in vapor-compression cycles to regulate the quality and flow rate of the refrigerant entering the evaporator. In vapor-compression systems, as the condensed refrigerant undergoes this expansion, its pressure and temperature drop, and part of the liquid evaporates. We (researchers at Kansas State University) are developing a cooling cycle that instead pumps a high-pressure refrigerant through a supersonic converging-diverging nozzle. As the liquid refrigerant passes through the nozzle, its velocity reaches supersonic (or critical-flow) conditions, substantially decreasing the refrigerant’s pressure. This sharp pressure change vaporizes some of the refrigerant and absorbs heat from the surrounding conditions during this phase change. Due to the design of the nozzle, a shockwave trips the supersonic two-phase refrigerant back to the starting conditions, condensing the remaining vapor. The critical-flow refrigeration cycle would provide space cooling, similar to a chiller, by running a secondary fluid such as water or glycol over one or more nozzles. Rather than utilizing a compressor to raise the pressure of the refrigerant, as in a vapor-cycle system, the critical-flow cycle utilizes a high-pressure pump to drive refrigerant liquid through the cooling cycle. Additionally, the design of the nozzle can be tailored for a given refrigerant, such that environmentally benign substances can act as the working fluid. This refrigeration cycle is still in early-stage development with prototype development several years away. The complex multi-phase flow at supersonic conditions presents numerous challenges to fully understanding and modeling the cycle. With the support of DOE and venture-capital investors, initial research was conducted at PAX Streamline, and later, at Caitin. We (researchers at Kansas State University) have continued development

  6. Personal, closed-cycle cooling and protective apparatus and thermal battery therefor

    DOEpatents

    Klett, James W.; Klett, Lynn B.

    2004-07-20

    A closed-cycle apparatus for cooling a living body includes a heat pickup body or garment which permits evaporation of an evaporating fluid, transmission of the vapor to a condenser, and return of the condensate to the heat pickup body. A thermal battery cooling source is provided for removing heat from the condenser. The apparatus requires no external power and provides a cooling system for soldiers, race car drivers, police officers, firefighters, bomb squad technicians, and other personnel who may utilize protective clothing to work in hostile environments. An additional shield layer may simultaneously provide protection from discomfort, illness or injury due to harmful atmospheres, projectiles, edged weapons, impacts, explosions, heat, poisons, microbes, corrosive agents, or radiation, while simultaneously removing body heat from the wearer.

  7. Structural stability of 1100{degree}C heated Pd/k during absorption cycling in protium

    SciTech Connect

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110{degree}C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100{degree}C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100{degree}C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100{degree}C.

  8. Low-cycle fatigue analysis of a cooled copper combustion chamber

    NASA Technical Reports Server (NTRS)

    Miller, R. W.

    1974-01-01

    A three-dimensional finite element elastoplastic strain analysis was performed for the throat section of regeneratively cooled rocket engine combustion chamber. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the engine operating cycle. The strain range was used in conjunction with OFHC copper isothermal fatigue test data to predict engine low-cycle fatigue life. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen chamber which was fatigue tested to failure at the NASA Lewis Research Center.

  9. Evaluation of Indirect Combined Cycle in Very High Temperature Gas--Cooled Reactor

    SciTech Connect

    Chang Oh; Robert Barner; Cliff Davis; Steven Sherman; Paul Pickard

    2006-10-01

    The U.S. Department of Energy and Idaho National Laboratory are developing a very high temperature reactor to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is twofold: (a) efficient, low-cost energy generation and (b) hydrogen production. Although a next-generation plant could be developed as a single-purpose facility, early designs are expected to be dual purpose, as assumed here. A dual-purpose design with a combined cycle of a Brayton top cycle and a bottom Rankine cycle was investigated. An intermediate heat transport loop for transporting heat to a hydrogen production plant was used. Helium, CO2, and a helium-nitrogen mixture were studied to determine the best working fluid in terms of the cycle efficiency. The relative component sizes were estimated for the different working fluids to provide an indication of the relative capital costs. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the cycle were performed to determine the effects of varying conditions in the cycle. This gives some insight into the sensitivity of the cycle to various operating conditions as well as trade-offs between efficiency and component size. Parametric studies were carried out on reactor outlet temperature, mass flow, pressure, and turbine cooling.

  10. Study on High Efficient Absorption Refrigerator Using Multi-effect Cycle

    NASA Astrophysics Data System (ADS)

    Inoue, Naoyuki; Irie, Tomoyoshi; Saito, Kiyoshi; Kawai, Sunao

    Double effect chillers are commonly used as cooling machines for air condition. Great efforts have been making to improve the efficiency for a long time, and now the COP is very near to the limitation of double effect cycles. Triple effect cycles are expected for the next step beyond double effect cycles, but have some problems of high temperature and high pressure in the high stage generator. High temperature of absorbent causes corrosion problem and high vapor pressure over atmospheric pressure causes the restriction of legal regulation. This paper deals with many types of triple effect cycles. The temperature and dew point of the high stage generator are analyzed, several types are selected for low dew point, and one of them is more analyzed in detail.

  11. A Gas-Cooled-Reactor Closed-Brayton-Cycle Demonstration with Nuclear Heating

    SciTech Connect

    Lipinski, Ronald J.; Wright, Steven A.; Dorsey, Daniel J.; Williamson, Joshua; Peters, Curtis D.; Brown, Nicholas; Jablonski, Jennifer

    2005-02-06

    A gas-cooled reactor may be coupled directly to turbomachinery to form a closed-Brayton-cycle (CBC) system in which the CBC working fluid serves as the reactor coolant. Such a system has the potential to be a very simple and robust space-reactor power system. Gas-cooled reactors have been built and operated in the past, but very few have been coupled directly to the turbomachinery in this fashion. In this paper we describe the option for testing such a system with a small reactor and turbomachinery at Sandia National Laboratories. Sandia currently operates the Annular Core Research Reactor (ACRR) at steady-state powers up to 4 MW and has an adjacent facility with heavy shielding in which another reactor recently operated. Sandia also has a closed-Brayton-Cycle test bed with a converted commercial turbomachinery unit that is rated for up to 30 kWe of power. It is proposed to construct a small experimental gas-cooled reactor core and attach this via ducting to the CBC turbomachinery for cooling and electricity production. Calculations suggest that such a unit could produce about 20 kWe, which would be a good power level for initial surface power units on the Moon or Mars. The intent of this experiment is to demonstrate the stable start-up and operation of such a system. Of particular interest is the effect of a negative temperature power coefficient as the initially cold Brayton gas passes through the core during startup or power changes. Sandia's dynamic model for such a system would be compared with the performance data. This paper describes the neutronics, heat transfer, and cycle dynamics of this proposed system. Safety and radiation issues are presented. The views expressed in this document are those of the author and do not necessarily reflect agreement by the government.

  12. A Gas-Cooled-Reactor Closed-Brayton-Cycle Demonstration with Nuclear Heating

    NASA Astrophysics Data System (ADS)

    Lipinski, Ronald J.; Wright, Steven A.; Dorsey, Daniel J.; Peters, Curtis D.; Brown, Nicholas; Williamson, Joshua; Jablonski, Jennifer

    2005-02-01

    A gas-cooled reactor may be coupled directly to turbomachinery to form a closed-Brayton-cycle (CBC) system in which the CBC working fluid serves as the reactor coolant. Such a system has the potential to be a very simple and robust space-reactor power system. Gas-cooled reactors have been built and operated in the past, but very few have been coupled directly to the turbomachinery in this fashion. In this paper we describe the option for testing such a system with a small reactor and turbomachinery at Sandia National Laboratories. Sandia currently operates the Annular Core Research Reactor (ACRR) at steady-state powers up to 4 MW and has an adjacent facility with heavy shielding in which another reactor recently operated. Sandia also has a closed-Brayton-Cycle test bed with a converted commercial turbomachinery unit that is rated for up to 30 kWe of power. It is proposed to construct a small experimental gas-cooled reactor core and attach this via ducting to the CBC turbomachinery for cooling and electricity production. Calculations suggest that such a unit could produce about 20 kWe, which would be a good power level for initial surface power units on the Moon or Mars. The intent of this experiment is to demonstrate the stable start-up and operation of such a system. Of particular interest is the effect of a negative temperature power coefficient as the initially cold Brayton gas passes through the core during startup or power changes. Sandia's dynamic model for such a system would be compared with the performance data. This paper describes the neutronics, heat transfer, and cycle dynamics of this proposed system. Safety and radiation issues are presented. The views expressed in this document are those of the author and do not necessarily reflect agreement by the government.

  13. Thermodynamic optimization of a solar system for cogeneration of water heating/purification and absorption cooling

    NASA Astrophysics Data System (ADS)

    Hovsapian, Zohrob O.

    This dissertation presents a contribution to understanding the behavior of solar powered air conditioning and refrigeration systems with a view to determining the manner in which refrigeration rate; mass flows, heat transfer areas, and internal architecture are related. A cogeneration system consisting of a solar concentrator, a cavity-type receiver, a gas burner, and a thermal storage reservoir is devised to simultaneously produce water heating/purification and cooling (absorption refrigerator system). A simplified mathematical model, which combines fundamental and empirical correlations, and principles of classical thermodynamics, mass and heat transfer, is developed. An experimental setup was built to adjust and validate the numerical results obtained with the mathematical model. The proposed model is then utilized to simulate numerically the system transient and steady state response under different operating and design conditions. A system global optimization for maximum performance (or minimum exergy destruction) in the search for minimum pull-down and pull-up times, and maximum system second law efficiency is performed with low computational time. Appropriate dimensionless groups are identified and the results presented in normalized charts for general application. The numerical results show that the three way maximized system second law efficiency, etaII,max,max,max, occurs when three system characteristic mass flow rates are optimally selected in general terms as dimensionless heat capacity rates, i.e., (Psisps , Psiwxwx, PsiHs)opt ≅ (1.43, 0.17, 0.19). The minimum pull-down and pull-up times, and maximum second law efficiencies found with respect to the optimized operating parameters are sharp and, therefore important to be considered in actual design. As a result, the model is expected to be a useful tool for simulation, design, and optimization of solar energy systems in the context of distributed power generation.

  14. Solar-powered/fuel-assisted Rankine cycle power and cooling system - Sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Lior, N.; Koai, K.

    1984-11-01

    The subject of this analysis is a solar power/cooling system based on a novel hybrid steam Rankine cycle. Steam is generated by the use of solar energy collected at about 100 C, and it is then superheated to about 600 C in a fossil-fuel-fired superheater. The addition of about 20-26 percent of energy as fuel doubles the power cycle's efficiency as compared to organic fluid Rankine cycles operating at similar collector temperatures. A sensitivity analysis of the system's performance to the size and type of its components was performed by a transient (hourly) computer simulation over the month of August in two representative climatic regions (Washington, D.C. and Phoenix, Ariz.), and led to the description of a system configuration which provides optimal energy performance. The newly designed turbine's predicted efficiency is seen to be essentially invariant with system configuration, and has a monthly average value of about 73 percent.

  15. A closed-cycle refrigerator for cooling maser amplifiers below 4 Kelvin

    NASA Technical Reports Server (NTRS)

    Britcliffe, M.

    1989-01-01

    A helium refrigerator utilizing the Gifford-McMahon/Joule-Thomson (GM/JT) cycle was designed and tested to demonstrate the feasibility of using small closed-cycle refrigerators as an alternative to batch-filled cryostats for operating temperatures below 4 K. The systems could be used to cool low-noise microwave maser amplifiers located in large parabolic antennas. These antennas tilt vertically, making conventional liquid-filled dewars difficult to use. The system could also be used for a non-tilting beam waveguide antenna to reduce the helium consumption of a liquid helium cryostat. The prototype system is adjustable to provide 700 mW of cooling at 2.5 K to 3 W at 4.3 K. Performance of the unit is not significantly affected by physical orientation. The volume occupied by the refrigerator is less than 0.1 cu m. Two JT expansion stages are used to maximize cooling capacity per unit mass flow. The heat exchangers were designed to produce minimum pressure drop in the return gas stream. Pressure drop for the entire JT return circuit is less than 5 kpa at a mass flow of 0.06 g/sec when operating at 2.5 K.

  16. Experimental Investigations on the Characteristics of the Ammonia-Water Absorption Refrigerator for Low Temperature Solution Cycle

    NASA Astrophysics Data System (ADS)

    Takei, Toshitaka; Kimijima, Shinji; Saito, Kiyoshi; Kawai, Sunao

    This report refers to some static characteristics of the ammonia-water absorption refrigerator for low temperature refrigerating process which needs the temperature below the freezing point. Especially, the influence of evaporating temperature and cooling water temperature is clarified by the experimental investigation. In addition to this, the validity of constructed simulation model of this absorption refrigerator is mentioned. The validity of simulation model is verified by the comparison of experimental results and calculation. To examine the characteristics, we conducted the performance test using the trial product of which the standard cooling capacity is 175kW. The performance is estimated according to cooling capacity and COP. As a result, the effects of the evaporating temperature and cooling water temperature on the cooling performance are clarified by the experimental research. Furthermore, the calculation of the static characteristics predicted by the simulation model is in good agreements with the experimental results.

  17. Sensitivity Analysis of Reprocessing Cooling Times on Light Water Reactor and Sodium Fast Reactor Fuel Cycles

    SciTech Connect

    R. M. Ferrer; S. Bays; M. Pope

    2008-04-01

    The purpose of this study is to quantify the effects of variations of the Light Water Reactor (LWR) Spent Nuclear Fuel (SNF) and fast reactor reprocessing cooling time on a Sodium Fast Reactor (SFR) assuming a single-tier fuel cycle scenario. The results from this study show the effects of different cooling times on the SFR’s transuranic (TRU) conversion ratio (CR) and transuranic fuel enrichment. Also, the decay heat, gamma heat and neutron emission of the SFR’s fresh fuel charge were evaluated. A 1000 MWth commercial-scale SFR design was selected as the baseline in this study. Both metal and oxide CR=0.50 SFR designs are investigated.

  18. Coupling a Supercritical Carbon Dioxide Brayton Cycle to a Helium-Cooled Reactor.

    SciTech Connect

    Middleton, Bobby; Pasch, James Jay; Kruizenga, Alan Michael; Walker, Matthew

    2016-01-01

    This report outlines the thermodynamics of a supercritical carbon dioxide (sCO2) recompression closed Brayton cycle (RCBC) coupled to a Helium-cooled nuclear reactor. The baseline reactor design for the study is the AREVA High Temperature Gas-Cooled Reactor (HTGR). Using the AREVA HTGR nominal operating parameters, an initial thermodynamic study was performed using Sandia's deterministic RCBC analysis program. Utilizing the output of the RCBC thermodynamic analysis, preliminary values of reactor power and of Helium flow rate through the reactor were calculated in Sandia's HelCO2 code. Some research regarding materials requirements was then conducted to determine aspects of corrosion related to both Helium and to sCO2 , as well as some mechanical considerations for pressures and temperatures that will be seen by the piping and other components. This analysis resulted in a list of materials-related research items that need to be conducted in the future. A short assessment of dry heat rejection advantages of sCO2> Brayton cycles was also included. This assessment lists some items that should be investigated in the future to better understand how sCO2 Brayton cycles and nuclear can maximally contribute to optimizing the water efficiency of carbon free power generation

  19. System design and analysis of hydrocarbon scramjet with regeneration cooling and expansion cycle

    NASA Astrophysics Data System (ADS)

    Wu, Xianyu; Yang, Jun; Zhang, Hua; Shen, Chibing

    2015-06-01

    A new expansion cycle scheme of the scramjet engine system including a hydrocarbon-fuel-based (kerosene) regenerativecooling system and supercritical/cracking kerosene-based turbo-pump was proposed in this paper. In this cycle scheme, the supercritical/cracking kerosene with high pressure and high temperature is formed through the cooling channel. And then, in order to make better use of the high energy of the supercritical/cracking fuel, the supercritical/cracking kerosene fuel was used to drive the turbo-pump to obtain a high pressure of the cold kerosenefuel at the entrance of the cooling channel. In the end, the supercritical/cracking kerosene from the turbine exit is injected into the scramjet combustor. Such supercritical/cracking kerosene fuel can decrease the fuel-air mixing length and increase the combustion efficiency, due to the gas state and low molecular weight of the cracking fuel. In order to ignite the cold kerosene in the start-up stage, the ethylene-assisted ignition subsystem was applied. In the present paper, operating modes and characteristics of the expansion cycle system are first described.And then, the overall design of the system and the characterisitics of the start-up process are analyzed numerically to investigate effects of the system parameters on the scramjet start-up performance. The results show that the expansion cycle system proposed in this paper can work well under typical conditions. The research work in this paper can help to make a solid foundation for the research on the coupling characteristics between the dynamicsand thermodynamics of the scramjet expansion cycle system

  20. Effect of Gas/Steam Turbine Inlet Temperatures on Combined Cycle Having Air Transpiration Cooled Gas Turbine

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Singh, O.

    2012-10-01

    Worldwide efforts are being made for further improving the gas/steam combined cycle performance by having better blade cooling technology in topping cycle and enhanced heat recovery in bottoming cycle. The scope of improvement is possible through turbines having higher turbine inlet temperatures (TITs) of both gas turbine and steam turbine. Literature review shows that a combined cycle with transpiration cooled gas turbine has not been analyzed with varying gas/steam TITs. In view of above the present study has been undertaken for thermodynamic study of gas/steam combined cycle with respect to variation in TIT in both topping and bottoming cycles, for air transpiration cooled gas turbine. The performance of combined cycle with dual pressure heat recovery steam generator has been evaluated for different cycle pressure ratios (CPRs) varying from 11 to 23 and the selection diagrams presented for TIT varying from 1,600 to 1,900 K. Both the cycle efficiency and specific work increase with TIT for each pressure ratio. For each TIT there exists an optimum pressure ratio for cycle efficiency and specific work. For the CPR of 23 the best cycle performance is seen at a TIT of 1,900 K for maximum steam temperature of 570 °C, which gives the cycle efficiency of 60.9 % with net specific work of 909 kJ/kg.

  1. Water-cooled hard-soldered kilowatt laser diode arrays operating at high duty cycle

    NASA Astrophysics Data System (ADS)

    Klumel, Genady; Karni, Yoram; Oppenhaim, Jacob; Berk, Yuri; Shamay, Moshe; Tessler, Renana; Cohen, Shalom; Risemberg, Shlomo

    2010-04-01

    High brightness laser diode arrays are increasingly found in defense applications either as efficient optical pumps or as direct energy sources. In many instances, duty cycles of 10- 20 % are required, together with precise optical collimation. System requirements are not always compatible with the use of microchannel based cooling, notwithstanding their remarkable efficiency. Simpler but effective solutions, which will not involve high fluid pressure drops as well as deionized water, are needed. The designer is faced with a number of challenges: effective heat removal, minimization of the built- in and operational stresses as well as precise and accurate fast axis collimation. In this article, we report on a novel laser diode array which includes an integral tap water cooling system. Robustness is achieved by all around hard solder bonding of passivated 940nm laser bars. Far field mapping of the beam, after accurate fast axis collimation will be presented. It will be shown that the design of water cooling channels , proper selection of package materials, careful design of fatigue sensitive parts and active collimation technique allow for long life time and reliability, while not compromising the laser diode array efficiency, optical power density ,brightness and compactness. Main performance characteristics are 150W/bar peak optical power, 10% duty cycle and more than 50% wall plug efficiency with less than 1° fast axis divergence. Lifetime of 0.5 Gshots with less than 10% power degradation has been proved. Additionally, the devices have successfully survived harsh environmental conditions such as thermal cycling of the coolant temperature and mechanical shocks.

  2. Soy-Based, Water-Cooled, TC W-III Two Cycle Engine Oil

    SciTech Connect

    Scharf, Curtis R.; Miller, Mark E.

    2003-08-30

    The objective of this project was to achieve technical approval and commercial launch for a biodegradable soy oil-based, environmentally safe, TC W-III performance, water-cooled, two cycle engine oil. To do so would: (1) develop a new use for RBD soybean oil; (2) increase soybean utilization in North America in the range of 500 K-3.0 MM bushels; and (3) open up supply opportunities of 1.5-5.0 MM bushels worldwide. These goals have been successfully obtained.

  3. Water chemistry of a combined-cycle power plant's auxiliary equipment cooling system

    NASA Astrophysics Data System (ADS)

    Larin, B. M.; Korotkov, A. N.; Oparin, M. Yu.; Larin, A. B.

    2013-04-01

    Results from an analysis of methods aimed at reducing the corrosion rate of structural metal used in heat-transfer systems with water coolant are presented. Data from examination of the closed-circuit system for cooling the auxiliary mechanisms of a combined-cycle plant-based power unit and the results from adjustment of its water chemistry are given. A conclusion is drawn about the possibility of using a reagent prepared on the basis of sodium sulfite for reducing the corrosion rate when the loss of coolant is replenished with nondeaerated water.

  4. A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides.

    PubMed

    Powell, J R; Salzano, F J; Yu, W S; Milau, J S

    1976-07-23

    A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output. PMID:17745726

  5. Thermodynamic modeling and performance analysis of the variable-temperature heat reservoir absorption heat pump cycle

    NASA Astrophysics Data System (ADS)

    Qin, Xiaoyong; Chen, Lingen; Ge, Yanlin; Sun, Fengrui

    2015-10-01

    For practical absorption heat pump (AHP) plants, not all external heat reservoir heat capacities are infinite. External heat reservoir heat capacity should be an effect factor in modeling and performance analysis of AHP cycles. A variable-temperature heat reservoir AHP cycle is modeled, in which internal working substance is working in four temperature levels and all irreversibility factors are considered. The irreversibility includes heat transfer irreversibility, internal dissipation irreversibility and heat leakage irreversibility. The general equations among coefficient of performance (COP), heating load and some key characteristic parameters are obtained. The general and optimal characteristics are obtained by using numerical calculations. Besides, the influences of heat capacities of heat reservoirs, internal dissipation irreversibility, and heat leakage irreversibility on cycle performance are analyzed. The conclusions can offer some guidelines for design and operation of AHP plants.

  6. POWER CYCLE AND STRESS ANALYSES FOR HIGH TEMPERATURE GAS-COOLED REACTOR

    SciTech Connect

    Oh, Chang H; Davis, Cliff; Hawkes, Brian D; Sherman, Steven R

    2007-05-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with three turbines and four compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with three stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and a 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to

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

    NASA Astrophysics Data System (ADS)

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

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

  8. Evidence for Solar Cycle Influence on the Infrared Energy Budget and Radiative Cooling of the Thermosphere

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Martin-Torres, F. Javier; Marshall, B. Thomas; Thompson, R. Earl; Williams, Joshua; Turpin, TImothy; Kratz, D. P.; Russell, James M.; Woods, Tom; Gordley, Larry L.

    2007-01-01

    We present direct observational evidence for solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. By analyzing nearly five years of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, we show that the annual mean infrared power radiated by the nitric oxide (NO) molecule at 5.3 m has decreased by a factor of 2.9. This decrease is correlated (r = 0.96) with the decrease in the annual mean F10.7 solar index. Despite the sharp decrease in radiated power (which is equivalent to a decrease in the vertical integrated radiative cooling rate), the variability of the power as given in the standard deviation of the annual means remains approximately constant. A simple relationship is shown to exist between the infrared power radiated by NO and the F10.7 index, thus providing a fundamental relationship between solar activity and the thermospheric cooling rate for use in thermospheric models. The change in NO radiated power is also consistent with changes in absorbed ultraviolet radiation over the same time period.

  9. New Fuel Cycle and Fuel Management Options in Heavy Liquid Metal-Cooled Reactors

    SciTech Connect

    Greenspan, Ehud; Hejzlar, Pavel; Sekimoto, Hiroshi; Toshinsky, Georgy; Wade, David

    2005-08-15

    Fast reactors cooled by lead or lead-bismuth alloy offer new interesting fuel cycle and fuel management options by virtue of the superb neutronics and safety features of these heavy liquid metal (HLM) coolants. One option is once-for-life cores having relatively low power density. These cores are fueled in the factory; there is no refueling or fuel shuffling on site. A second option is very long-life cores being made of a fissioning zone and a natural uranium blanket zone. The fissioning zone very slowly drifts toward the blanket. A third option is multirecycling of light water reactor (LWR) discharged fuel without partitioning of transuranics (TRUs) in fuel-self-sustaining reactors. LWR spent fuel could provide the initial fuel loading after extracting fission products and {approx}90% of its uranium. The makeup fuel is natural or depleted uranium. A fourth option is the high-burnup once-through fuel cycle using natural or depleted uranium feed. The initial fuel loading of this reactor is a mixture of enriched and natural uranium. The natural uranium utilization is 10 to 20 times higher than that of a once-through LWR. A fifth option is transmutation of TRUs from LWRs using critical HLM-cooled reactors; such reactors could be designed to have the same high actinide burning capability of accelerator-driven systems and have comparable safety, but at a substantially lower cost. These novel reactor designs and fuel management options are hereby reviewed.

  10. Development of a single-family absorption chiller for use in a solar heating and cooling system. Phase III, final report. Volume II

    SciTech Connect

    Reimann, R.C.; Biermann, W.J.

    1984-10-01

    The appendices provide supporting information on: properties of a chemical system for solar fired, air-cooled absorption equipment, air-side performance of a one-inch tube, absorber plate-fin coil, listings of the programs used for simulation and data reduction, and evaluation of the Carrier 3-ton chiller in an integrated heating and cooling system. (LEW)

  11. Development of a single-family absorption chiller for use in a solar heating and cooling system, phase 3, volume 2

    NASA Astrophysics Data System (ADS)

    Reimann, R. C.; Biermann, W. J.

    1984-10-01

    Supporting information is presented on: properties of a chemical system for solar fired, air-cooled absorption equipment, air-side performance of a one-inch tube, absorber plate-fin coil, listings of the programs used for simulation and data reduction, and evaluation of the Carrier three-tone chiller in an integrated heating and cooling system.

  12. The absorption process for heating, cooling and energy storage - An historical survey

    NASA Astrophysics Data System (ADS)

    Bjurstrom, H.; Raldow, W.

    1981-03-01

    A historical overview of the absorption process is given and a wide range of applications, from household refrigerators and air conditioners to topping processes in power plants, are surveyed in historical perspective. The production of mechanical energy and open systems are also included. The current development of the absorption process is sketched out and special attention is given to the aspects of thermal energy storage.

  13. Thermal Cycling Absorption Process (TCAP): Instrument and Simulation Development Status at Los Alamos National Laboratory

    SciTech Connect

    Arias, Angela A.; Schmierer, Eric N.; Gettemy, Donald; Howard, David W.; Wermer, Joseph R.; Tuggle, Dale G.

    2005-07-15

    The Thermal Cycling Absorption Process (TCAP) Project at Los Alamos National Laboratory has been a collaborative effort with Savannah River Site to demonstrate the Tube-in-Tube (TnT) column design and to improve TCAP science. TnT TCAP is an alternative design which uses a liquid to thermally cycle the metal hydride packed column. Inert gas displacement tests and deuterium pulse tests have been performed on the TnT TCAP column. The inert gas displacement tests are designed to measure plug flow in the column while the deuterium pulse tests determine the separation ability of the column. A residual gas analyzer measures the gases in the exit stream and the experimental results are compared with pulse test model results.

  14. Organic Fluids and Passive Cooling in a Supercritical Rankine Cycle for Power Generation from Low Grade Heat Sources

    NASA Astrophysics Data System (ADS)

    Vidhi, Rachana

    Low grade heat sources have a large amount of thermal energy content. Due to low temperature, the conventional power generation technologies result in lower efficiency and hence cannot be used. In order to efficiently generate power, alternate methods need to be used. In this study, a supercritical organic Rankine cycle was used for heat source temperatures varying from 125°C to 200°C. Organic refrigerants with zero ozone depletion potential and their mixtures were selected as working fluid for this study while the cooling water temperature was changed from 10-25°C. Operating pressure of the cycle has been optimized for each fluid at every heat source temperature to obtain the highest thermal efficiency. Energy and exergy efficiencies of the thermodynamic cycle have been obtained as a function of heat source temperature. Efficiency of a thermodynamic cycle depends significantly on the sink temperature. At areas where water cooling is not available and ambient air temperature is high, efficient power generation from low grade heat sources may be a challenge. Use of passive cooling systems coupled with the condenser was studied, so that lower sink temperatures could be obtained. Underground tunnels, buried at a depth of few meters, were used as earth-air-heat-exchanger (EAHE) through which hot ambient air was passed. It was observed that the air temperature could be lowered by 5-10°C in the EAHE. Vertical pipes were used to lower the temperature of water by 5°C by passing it underground. Nocturnal cooling of stored water has been studied that can be used to cool the working fluid in the thermodynamic cycle. It was observed that the water temperature can be lowered by 10-20°C during the night when it is allowed to cool. The amount of water lost was calculated and was found to be approximately 0.1% over 10 days. The different passive cooling systems were studied separately and their effects on the efficiency of the thermodynamic cycle were investigated. They were

  15. Performance Analysis of the Absorption Refrigeration Cycle using TFE/NMP as a Working Fluid

    NASA Astrophysics Data System (ADS)

    Kato, Masashi; Tsujimori, Atsushi; Nakaguchi, Kentaro; Yabune, Hiroyuki; Akutsu, Toshinosuke; Nakao, Kazusige

    Performance analysis was made for the generator of the absorption refrigeration cycle using TFE/NMP as a working fluid. In this study the dynamic model was constructed. This model includes the heat and mass transfer characteristics in the generator and is able to predict the outlet concentration and the flow rate of the generated refrigerant vapor according to the change of the operating conditions of the absorption refrigeration cycle. The heat transfer in the generator was decided giving the heat transfer coefficient with temperature difference between the heat transfer wall of the generator and the solution. And the mass transfer was decided giving the over-all mass transfer coefficient between the solution bulk flow and the generated refrigerant bubbles. In this study the change of the concentration and the flow rate of the generated refrigerant vapor was mainly calculated when the strong solution flow rate, the generator wall temperature and the generation pressure were dynamically increased in incremental steps. And in starting and stopping the system, the effect of the generative heat transfer coefficient, over-all mass transfer coefficient and the strong solution flow rate were investigated.

  16. Marine biological productivity, carbon cycling, and climate cooling during the Oligocene to Miocene transition

    NASA Astrophysics Data System (ADS)

    Diester-Haass, Liselotte; Billups, Katharina; Emeis, Kay-Christian

    2010-05-01

    The Oligocene to Miocene boundary (the so-called Mi1 event) marks one of the major Cenozoic cooling steps. A corresponding but slightly out of phase 13C maximum has been attributed to increased organic matter burial associated with global climate cooling (e.g., Zachos et al., 2001). To test this idea we have constructed records of marine biological productivity (based on benthic foraminiferal accumulation rates, BFAR) to parallel the stable isotope records from 20-25 Ma at three sites from the Atlantic Ocean sampling different hydrographic regimes. Our data show that the 18O and 13C maximum that characterize the Oligocene/Miocene boundary is accompanied by a pronounced maximum in BFAR derived paleoproductivity at all sites. In the subtropical Atlantic (Site 1265) and the Southern Ocean (Site 1090), productivity increases about 500 kyr prior to Mi1 in tune with the beginning of enhanced amplitude variations in the benthic foraminiferal 13C record. In the tropical Atlantic (Site 926), where we have appropriate sampling resolution (~10 kyr), eccentricity-scale variations in paleoproductivity are coherent with the stable isotope records and in-phase with the 18O values. Paleoproductivity leads 13C at the 400 kyr period in agreement with the lead of 18O values with respect to 13C values. These results illustrate that the link between Oligocene to Miocene climate transition and the carbon cycle is one of marine primary productivity both during the glacial event of Mi1 as well as on eccentricity time scales. The late Oligocene (24 Ma) increase of productivity suggests that a reduction of atmospheric CO2 levels mediated by increased biological productivity may have lead to climate cooling at the Oligocene to Miocene boundary.

  17. Optimization of a solar powered absorption cycle under Abu Dhabi's weather conditions

    SciTech Connect

    Al-Alili, A.; Hwang, Y.; Radermacher, R.; Kubo, I.

    2010-12-15

    In order for the solar absorption air conditioners to become a real alternative to the conventional vapour compression systems, their performance has to be improved and their total cost has to be reduced. A solar powered absorption cycle is modeled using the Transient System Simulation (TRNSYS) program and Typical Meteorological Year 2 data of Abu Dhabi. It uses evacuated tube collectors to drive a 10 kW ammonia-water absorption chiller. Firstly, the system performance and its total cost are optimized separately using single objective optimization algorithms. The design variables considered are: the collector slope, the collector mass flow rate, the collector area and the storage tank volume. The single objective optimization results show that MATLAB global optimization methods agree with the TRNSYS optimizer. Secondly, MATLAB is used to solve a multi-objective optimization problem to improve the system's performance and cost, simultaneously. The optimum designs are presented using Pareto curve and show the potential improvements of the baseline system. (author)

  18. Strong neutrino cooling by cycles of electron capture and β- decay in neutron star crusts.

    PubMed

    Schatz, H; Gupta, S; Möller, P; Beard, M; Brown, E F; Deibel, A T; Gasques, L R; Hix, W R; Keek, L; Lau, R; Steiner, A W; Wiescher, M

    2014-01-01

    The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, β(-) decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This 'Urca' mechanism has been studied in the context of white dwarfs and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface. PMID:24291788

  19. Strong neutrino cooling by cycles of electron capture and decay in neutron star crusts

    SciTech Connect

    Schatz, Hendrik; Gupta, Sanjib; Moeller, Peter; Beard, Mary; Brown, Edward; Deibel, A. T.; Gasques, Leandro; Hix, William Raphael; Keek, Laurens; Lau, Rita; Steiner, Andrew M; Wiescher, Michael

    2013-01-01

    The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This Urca mechanism has been studied in the context of white dwarfs13 and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models1, 2 computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface.

  20. Carbon Dioxide Absorption Heat Pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  1. 1- and 2-photon absorption by laser-cooled 85Rb using an optical nanofiber

    NASA Astrophysics Data System (ADS)

    Russell, L.; Daly, M.; Chormaic, S. Nic

    2012-09-01

    The characteristics of a cold cloud of 85Rb can be non-destructively examined using an optical nanofiber. The nanofiber is a submicron-diameter cylindrical waveguide fabricated from commercially-available optical fiber using a heat-and-pull rig. The nanofiber can be used as a 'dark' or 'bright' probe depending on whether laser light is coupled into the nanofiber. We demonstrate the use of an optical nanofiber as an absorption spectroscopy tool for cold atoms. A frequency-scanned probe beam is launched through the nanofiber and the resonant light is absorbed at the waist of the nanofiber by nearby cold 85Rb atoms. We present recent singlephoton absorption results and comment on the role of surface interactions. Future work on 2-photon absorption using excited state electronic transitions in 85Rb is discussed.

  2. Supercontinuum based absorption spectrometer for cycle-resolved multiparameter measurements in a rapid compression machine.

    PubMed

    Werblinski, Thomas; Kleindienst, Stefan; Engelbrecht, Rainer; Zigan, Lars; Will, Stefan

    2016-06-10

    A broadband supercontinuum (SC) based absorption spectrometer capable of cycle-resolved multiparameter measurements at internal combustion (IC) engine conditions is presented. Three parameters, temperature, pressure and water mole fraction, were extracted from broadband near-infrared H2O absorption spectra, spanning the wavelength-range from 1340 to 1405.5 nm, which exhibits a large number of specific H2O transitions. The spectrometer is based on spatial domain detection and features a near-infrared line scan camera as a detector. Measurements were performed during a compression cycle of a rapid compression machine comprising a pressure and temperature range from 2.5 to 65 bar and 300 to 900 K, respectively. With the new spectrometer, we are for the first time, based on the authors' knowledge, able to perform measurements based on SC radiation over a complete compression and expansion stroke at measurement rates up to 50 kHz. A detailed overview is provided about the best match algorithm between theory and experiments, including parameters from two different spectral databases, namely the Barber-Tennyson database (BT2) and HITRAN2012. The results indicate that spectral broadening effects are not properly described by theory, especially at pressure levels exceeding 20 bar, which culminates in a clear underestimation of the derived pressure data by SC absorption spectroscopy. Nevertheless, temperature can be determined accurately by performing a three-parameter fit based on water mole fraction, temperature, and pressure. In contrast, making use of pressure transducer data as look-up values and varying only temperature and H2O mole fraction to find the best match leads to a clear overestimation of temperature at elevated pressures. PMID:27409013

  3. Interim Report: Air-Cooled Condensers for Next Generation Geothermal Power Plants Improved Binary Cycle Performance

    SciTech Connect

    Daniel S. Wendt; Greg L. Mines

    2010-09-01

    As geothermal resources that are more expensive to develop are utilized for power generation, there will be increased incentive to use more efficient power plants. This is expected to be the case with Enhanced Geothermal System (EGS) resources. These resources will likely require wells drilled to depths greater than encountered with hydrothermal resources, and will have the added costs for stimulation to create the subsurface reservoir. It is postulated that plants generating power from these resources will likely utilize the binary cycle technology where heat is rejected sensibly to the ambient. The consumptive use of a portion of the produced geothermal fluid for evaporative heat rejection in the conventional flash-steam conversion cycle is likely to preclude its use with EGS resources. This will be especially true in those areas where there is a high demand for finite supplies of water. Though they have no consumptive use of water, using air-cooling systems for heat rejection has disadvantages. These systems have higher capital costs, reduced power output (heat is rejected at the higher dry-bulb temperature), increased parasitics (fan power), and greater variability in power generation on both a diurnal and annual basis (larger variation in the dry-bulb temperature). This is an interim report for the task ‘Air-Cooled Condensers in Next- Generation Conversion Systems’. The work performed was specifically aimed at a plant that uses commercially available binary cycle technologies with an EGS resource. Concepts were evaluated that have the potential to increase performance, lower cost, or mitigate the adverse effects of off-design operation. The impact on both cost and performance were determined for the concepts considered, and the scenarios identified where a particular concept is best suited. Most, but not all, of the concepts evaluated are associated with the rejection of heat. This report specifically addresses three of the concepts evaluated: the use of

  4. Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigeration for lesser developed countries

    NASA Astrophysics Data System (ADS)

    Erickson, Donald C.

    1990-02-01

    The Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigerator is a solar thermal technology which provides low cost, efficient, reliable ice-making to areas without ready access to electricity. An ISAAC refrigeration system consists of a compound parabolic solar collector, two pressure vessels, a condenser, a cold box or refrigerated space, and simple connective piping -- no moving parts or electrical components. Most parts are simple construction or plumbing grade materials, locally available in many remote areas. This technology has numerous potential benefits in lesser developed countries both by providing a cheap, reliable source of ice, and, since manufacture requires only semi-skilled labor, a source of employment to the local economy. Applications include vaccine storage for health care clinics; fish, meat, and dairy product storage; and personal consumption. Importantly, this technology increases the quality of life for people in lesser developed countries without depleting fossil fuel resources or increasing the release of greenhouse gases such as CO2 and chlorofluorocarbons.

  5. Optimization of absorption air-conditioning for solar energy applications

    NASA Technical Reports Server (NTRS)

    Perry, E. H.

    1976-01-01

    Improved performance of solar cooling systems using the lithium bromide water absorption cycle is investigated. Included are computer simulations of a solar-cooled house, analyses and measurements of heat transfer rates in absorption system components, and design and fabrication of various system components. A survey of solar collector convection suppression methods is presented.

  6. Simulation model of a single-stage lithium bromide-water absorption cooling unit

    NASA Technical Reports Server (NTRS)

    Miao, D.

    1978-01-01

    A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.

  7. The integrated radio continuum spectrum of M33 - Evidence for free-free absorption by cool ionized gas

    NASA Technical Reports Server (NTRS)

    Israel, F. P.; Mahoney, M. J.; Howarth, N.

    1992-01-01

    We present measurements of the integrated radio continuum flux density of M33 at frequencies between 22 and 610 MHz and discuss the radio continuum spectrum of M33 between 22 MHz and 10 GHz. This spectrum has a turnover between 500 and 900 MHz, depending on the steepness of the high frequency radio spectrum of M33. Below 500 MHz the spectrum is relatively flat. We discuss possible mechanisms to explain this spectral shape and consider efficient free-free absorption of nonthermal emission by a cool (not greater than 1000 K) ionized gas to be a very likely possibility. The surface filling factor of both the nonthermal and the thermal material appears to be small (of order 0.001), which could be explained by magnetic field/density fluctuations in the M 33 interstellar medium. We briefly speculate on the possible presence of a nuclear radio source with a steep spectrum.

  8. Paleoecology of cool-water, subtidal cycles in mid-cenozoic limestones, Eucla Platform, Southern Australia

    SciTech Connect

    James, N.P.; Bone, Y.

    1994-10-01

    The open-shelf, subtidal, bryozoan-rich Abrakurrie Limestone beneath the Nullarbor Plain (Eucla Platform) is cyclic at the meter-scale. Best developed cycles are asymmetric and comprise three distinct parts with a capping hardground. The basal part (A) is a thin, coarse, grainstone or rudstone that is rich in robust bryosoan and epifaunal echinoid fragments and pecten bivalves, reflecting growth and accumulation in generally high energy, hard bottom environments. The middle part (B), intepreted as a low-energy, sub-swellbase accumulation, is a burrowed to planar cross-laminated fine grainstone or packstone with a low diversity, delicate-branching bryozoan assemblage and little else except scattered infaunal echinoids and pectens. The upper part (C) is a burrowed, abundantly fossilferous (bryozoan, bivalve, echinoid) rudstone or floatstone. Upward increases in the numbers and diversity of Mg-calcite and aragonitic cheilostome bryozoans (especially erect rigid, flat robust branching and nodular/arborescent types), gastropods, infaunal bivalves, and infaunal echinoids points to a high-energy environment. Sediments at the top of C are variably cemented by inclusion-rich marine cement (now calcite) that formed a hardground which was subsequently physically and biologically eroded and stained by iron oxides during a period of non-deposition. Sediments from the next overlying cycle succeed cements in uppermost intergranular pores and fill open crustacean burrows. Variably developed cyclicity is interpreted, on the basis of comparable Holocene cool-water shelf sediments, to reflect deposition in generally sub-photic environments that ranged from just below swell base (B) upwards towards the zone of wave abrasion (A and C). Hardgrounds (H) formed when the seafloor was within the zone of wave abrasion. Shallowing and deepening of these critical interfaces was controlled by fluctuating sea level and/or climatic change. 55 refs., 12 figs.

  9. Emittance and absorptance of NASA ceramic thermal barrier coating system. [for turbine cooling

    NASA Technical Reports Server (NTRS)

    Liebert, C. H.

    1978-01-01

    Spectral emittance measurements were made on a two-layer ceramic thermal barrier coating system consisting of a metal substrate, a NiCrAly bond coating and a yttria-stabilized zirconia ceramic coating. Spectral emittance data were obtained for the coating system at temperatures of 300 to 1590 K, ceramic thickness of zero to 0.076 centimeter, and wavelengths of 0.4 to 14.6 micrometers. The data were transformed into total hemispherical emittance values and correlated with respect to ceramic coating thickness and temperature using multiple regression curve fitting techniques. The results show that the ceramic thermal barrier coating system is highly reflective and significantly reduces radiation heat loads on cooled gas turbine engine components. Calculation of the radiant heat transfer within the nonisothermal, translucent ceramic coating material shows that the gas-side ceramic coating surface temperature can be used in heat transfer analysis of radiation heat loads on the coating system.

  10. HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

    SciTech Connect

    Gorensek, M.

    2011-07-06

    Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.

  11. Characterization of external quantum efficiency and absorption efficiency in GaAs/ InGaP double heterostructures for laser cooling applications

    NASA Astrophysics Data System (ADS)

    Wang, Chengao; Hasselbeck, Michael P.; Li, Chia-Yeh; Sheik-Bahae, Mansoor

    2010-02-01

    The state of current research in laser cooling of semiconductors is reviewed. Emphasis is placed on the characterization of external quantum efficiency and absorption efficiency in GaAs/InGaP double heterostuctures. New experimental results will be presented that characterize device operation as a function of laser excitation power and temperature. Optimum carrier density is obtained independently and used as a screening tool for sample quality. The crucial importance of parasitic background absorption is discussed.

  12. The effect of mass recovery adsorption cooling cycle to optimize the collector number and time allocation

    NASA Astrophysics Data System (ADS)

    Kabir, K. M. Ariful; Alam, K. C. Amanul; Rouf, Rifat A.; Sarker, M. M. A.

    2016-07-01

    The performance of mass recovery for solar adsorption cooling system has been investigated numerically. Solar adsorption cooling appears to have a prospect in tropical region. Though it has a huge installation cost, its long term payback could be a considerable fact. Mass recovery scheme increases Average Cooling Capacity (ACC) and Coefficient of Performance (COP) values of the adsorption cooling system. In intension to reduce cost and maximize system performance, a two bed solar driven conventional cooling system run by silica gel and water along with mass recovery process has been investigated mathematically.

  13. Impact of Cooling Rate-Induced Recrystallization on High G Mechanical Shock and Thermal Cycling in Sn-Ag-Cu Solder Interconnects

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Kyu; Bieler, Thomas R.; Kim, Choong-Un

    2016-01-01

    The mechanical stability and thermo-mechanical fatigue performance of solder joints with low silver content Sn-1.0Ag-0.5Cu (wt.%) (SAC105) alloy based on different cooling rates are investigated in high G level shock environment and thermal cycling conditions. The cooling rate-controlled samples ranging from 1°C/min to 75°C/min cooling rate, not only show differences in microstructure, where a fine poly-granular microstructure develops in the case of fast cooling versus normal cooling, but also show various shock performances based on the microstructure changes. The fast cooling rate improves the high G shock performance by over 90% compared to the normal cooled SAC105 alloy air-cooling environment commonly used after assembly reflow. The microstructure effect on thermal cycling performance is also discussed, which is analyzed based on the Sn grain orientation, interconnect stability, and solder joint bulk microstructure.

  14. The effect of cooling management on blood flow to the dominant follicle and estrous cycle length at heat stress.

    PubMed

    Honig, Hen; Ofer, Lior; Kaim, Moshe; Jacobi, Shamay; Shinder, Dima; Gershon, Eran

    2016-07-15

    The use of ultrasound imaging for the examination of reproductive organs has contributed substantially to the fertility management of dairy cows around the world. This method has many advantages such as noninvasiveness and immediate availability of information. Adding Doppler index to the ultrasound imaging examination, improved the estimation of blood volume and flow rate to the ovaries in general and to the dominant follicle in particular. The aim of this study was to examine changes in the blood flow to the dominant follicle and compare them to the follicular development throughout the cycle. We further set out to examine the effects of different types of cooling management during the summer on the changes in blood flow to the dominant follicle. For this purpose, 24 Israeli-Holstein dairy cows, under heat stress, were randomly assigned one of two groups: one was exposed to five cooling sessions per day (5CS) and the other to eight cooling sessions per day (8CS). Blood flow to the dominant follicle was measured daily using Doppler index throughout the estrous cycle. No differences in the preovulatory dominant follicle diameter were detected between the two cooling management regimens during the cycle. However, the length of the first follicular wave was significantly longer, whereas the second follicular wave was nonsignificantly shorter in the 5CS group as compared to the 8CS group. In addition, no difference in blood flow was found during the first 18 days of the cycle between the two groups. However, from Day 20 until ovulation a higher rate of blood flow was measured in the ovaries of cows cooled 8 times per day as compared to the 5CS group. No differences in progesterone levels were noted. Finally, the estrous cycle length was shorter in the 8CS group as compared to the 5CS group. Our data suggest that blood flow to the dominant follicle and estrous cycle length is affected by heat stress. Using the appropriate cooling management during heat stress can

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

    NASA Astrophysics Data System (ADS)

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

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

  16. Optimization of power-cycle arrangements for Supercritical Water cooled Reactors (SCWRs)

    NASA Astrophysics Data System (ADS)

    Lizon-A-Lugrin, Laure

    The world energy demand is continuously rising due to the increase of both the world population and the standard of life quality. Further, to assure both a healthy world economy as well as adequate social standards, in a relatively short term, new energy-conversion technologies are mandatory. Within this framework, a Generation IV International Forum (GIF) was established by the participation of 10 countries to collaborate for developing nuclear power reactors that will replace the present technology by 2030. The main goals of these nuclear-power reactors are: economic competitiveness, sustainability, safety, reliability and resistance to proliferation. As a member of the GIF, Canada has decided to orient its efforts towards the design of a CANDU-type Super Critical Water-cooled Reactor (SCWR). Such a system must run at a coolant outlet temperature of about 625°C and at a pressure of 25 MPa. It is obvious that at such conditions the overall efficiency of this kind of Nuclear Power Plant (NPP) will compete with actual supercritical water-power boilers. In addition, from a heat-transfer viewpoint, the use of a supercritical fluid allows the limitation imposed by Critical Heat Flux (CHF) conditions, which characterize actual technologies, to be removed. Furthermore, it will be also possible to use direct thermodynamic cycles where the supercritical fluid expands right away in a turbine without the necessity of using intermediate steam generators and/or separators. This work presents several thermodynamic cycles that could be appropriate to run SCWR power plants. Improving both thermal efficiency and mechanical power constitutes a multi-objective optimization problem and requires specific tools. To this aim, an efficient and robust evolutionary algorithm, based on genetic algorithm, is used and coupled to an appropriate power plant thermodynamic simulation model. The results provide numerous combinations to achieve a thermal efficiency higher than 50% with a

  17. Solid Desiccant Cooling System Employed with Ventilation Cycle: A Sensitivity Analysis

    NASA Astrophysics Data System (ADS)

    Parmar, H.; Hindoliya, D. A.

    2012-10-01

    For better use of evaporative cooling techniques in humid climate, employment of desiccant cooling system (DCS) can be a suitable option. Desiccant augmented evaporative cooling system may be employed for energy saving in buildings in place of conventional vapour compression based cooling system. This article presents a sensitive analysis of DCS simulated under the humid climate of Mumbai, India. Mathematical computations have been performed using outdoor specific humidity, ambient dry bulb temperature and room supply temperature. A sensitive analysis considering some important forcing parameters was conducted. It was observed that the "effectiveness" of direct evaporative cooler to be predominantly high influencing parameter compared to others, for the performance of DCS.

  18. Developments in absorptive glass mat separators for cycling applications and 36 V lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Toniazzo, V.; Lambert, U.

    The major markets for valve-regulated lead-acid (VRLA) batteries are undergoing a radical upheaval. In particular, the telecommunications industry requires more reliable power supplies, and the familiar 12 V electrical system in cars will probably be soon replaced by a 36/42 V system, or by other electrical systems if part of the automotive market is taken over by hybrid electrical vehicles (HEVs). In order to meet these new challenges and enable VRLA batteries to provide a satisfactory life in float and cycling applications in the telecommunication field, or in the high-rate-partial-state-of-charge service required by both 36/42 V automobiles and HEVs, the lead-acid battery industry has to improve substantially the quality of present VRLA batteries based on absorptive glass mat (AGM) technology. Therefore, manufacturing steps and cell components have to be optimized, especially AGM separators as these are key components for better production yields and battery performance. This paper shows how the optimal segregation of the coarse and fine fibres in an AGM separator structure can improve greatly the properties of the material. The superior capillarity, springiness and mechanical properties of the 100% glass Amerglass multilayer separator compared with commercial monolayer counterparts with the same specific surface-area is highlighted.

  19. Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids.

    PubMed

    Ferrebee, Courtney B; Dawson, Paul A

    2015-03-01

    The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5). PMID:26579438

  20. Structural stability of 1100[degree]C heated Pd/k during absorption cycling in protium. [Palladium supported on kieselguhr

    SciTech Connect

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110[degree]C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100[degree]C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100[degree]C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100[degree]C.

  1. Static Characteristics of Absorption Chiller-Heater Supplying Cold and Hot Water Simultaneously

    NASA Astrophysics Data System (ADS)

    Inoue, Naoyuki; Irie, Tomoyoshi

    Absorption chiller-heaters which can supply both chilled water and hot water at the same time, are used for cooling and heating air conditioning systems. In this paper, we classified absorption cold and hot water generating cycles and control methods, studied these absorption cycles by cycle simulation. In economizer cycle, condensed refrigerant which heats hot water is transported to cooling cycle and used effectively for cooling chilled water, Concerning with transported condensed refrigerant, there are two methods, all condensed refrigerant or required refrigerant for cooling are transported to cooling cycle, and required refrigerant method is better for energy saving. Adding improvement of solution control to this economizer cycle, simultaneous cold and hot water supplying chiller-heaters have good characteristics of energy saving in the all region.

  2. Design and Economic Analysis of a Heating/Absorption Cooling System Operating with Municipal Solid Waste Digester: A Case Study of Gazi University

    NASA Astrophysics Data System (ADS)

    Coşar, Gökhan; Pooyanfar, Mirparham; Amirabedin, Ehsan; Topal, Hüseyin

    2013-12-01

    Recovering energy from municipal solid waste (MSW) is one of the most important issues of energy management in developed countries. This raises even more interest as world fossil fuel reserves diminish and fuel prices rise. Being one of main processes of waste disposal, anaerobic digestion can be used as a means to reduce fossil fuel and electricity consumption as well as reducing emissions. With growing demand for cooling in Turkey, especially during warm seasons and considering the energy costs, utilizing heat-driven absorption cooling systems coupled with an anaerobic digester for local cooling purposes is a potentially interesting alternative for electricity driven compression cooling. The aim of this article is to study the viability of utilizing biogas obtained from MSW anaerobic digestion as the main fuel for heating facilities of Gazi University, Turkey and also the energy source for an absorption cooling system designed for the central library of the aforementioned campus. The results prove that the suggested system is sustainably and financially appealing and has the potential to replace the conventional electricity driven cooling systems with a reasonable net present worth; moreover, it can notably reduce carbon dioxide emissions.

  3. Influence of Accelerated Cooling Condition on Welding Thermal Cycle, Residual Stress, and Deformation in SM490A Steel ESW Joint

    NASA Astrophysics Data System (ADS)

    Deng, Dean; Sun, Jiamin; Dai, Deping; Jiang, Xiaohua

    2015-09-01

    Electro-slag welding (ESW) has been widely used to join the box column because of high productivity. The heat input of ESW is far larger than those of other fusion welding processes, so ESW usually results in a long holding time over certain elevated temperature (∆ t H time), a long cooling time from 800 to 500 °C (∆ t 8/5 time), and a wide heat-affected zone (HAZ). It can be foreseen that the mechanical properties especially fracture toughness of the fusion zone and HAZ will be inferior to those of base metal. As a fundamental research, a computational approach based on MSC.Marc code was developed to simulate the thermo-mechanical behaviors in a typical SM490A steel ESW joint under different cooling conditions. Meanwhile, the thermal cycles computed by numerical model were compared with the experimental measurements. Moreover, the influence of accelerated cooling methods on welding residual stress and deformation was examined numerically. Simulation results show that accelerated cooling methods not only can largely shorten ∆ t H time as well as ∆ t 8/5 time and reduce the size of HAZ, but also can affect the residual stress distribution and deformation. It is believed that the accelerated cooling methods proposed by this study potentially improve the mechanical properties of ESW joint.

  4. Thermal and economic assessment of hot side sensible heat and cold side phase change storage combination fo absorption solar cooling system

    NASA Astrophysics Data System (ADS)

    Choi, M. K.; Morehouse, J. H.

    An analysis of a solar assisted absorption cooling system which employs a combination of phase change on the cold side and sensible heat storage on the hot side of the cooling machine for small commercial buildings is given. The year-round thermal performance of this system for space cooling were determined by simulation and compared against conventional cooling systems in three geographic locations: Phoenix, Arizona; Miami, Florida and Washington, D.C. The results indicate that the hot-cold storage combination has a considerable amount of energy and economical savings over hot side sensible heat storage. Using the hot-cold storage combination, the optimum collector areas for Washington, D.C., Phoenix and Miami are 355 m squared, 250 m squared and 495 m squared, respectively. Compared against conventional vapor compression chiller, the net solar fractions are 61, 67 and 69 percent, respectively.

  5. Preliminary Design Study of Medium Sized Gas Cooled Fast Reactor with Natural Uranium as Fuel Cycle Input

    NASA Astrophysics Data System (ADS)

    Meriyanti, Su'ud, Zaki; Rijal, K.; Zuhair, Ferhat, A.; Sekimoto, H.

    2010-06-01

    In this study a fesibility design study of medium sized (1000 MWt) gas cooled fast reactors which can utilize natural uranium as fuel cycle input has been conducted. Gas Cooled Fast Reactor (GFR) is among six types of Generation IV Nuclear Power Plants. GFR with its hard neuron spectrum is superior for closed fuel cycle, and its ability to be operated in high temperature (850° C) makes various options of utilizations become possible. To obtain the capability of consuming natural uranium as fuel cycle input, modified CANDLE burn-up scheme[1-6] is adopted this GFR system by dividing the core into 10 parts of equal volume axially. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 70 W/cc. As an optimization results, a design of 1000 MWt reactors which can be operated 10 years without refueling and fuel shuffling and just need natural uranium as fuel cycle input is discussed. The average discharge burn-up is about 280 GWd/ton HM. Enough margin for criticallity was obtained for this reactor.

  6. Preliminary Design Study of Medium Sized Gas Cooled Fast Reactor with Natural Uranium as Fuel Cycle Input

    SciTech Connect

    Meriyanti; Su'ud, Zaki; Rijal, K.; Zuhair; Ferhat, A.; Sekimoto, H.

    2010-06-22

    In this study a feasibility design study of medium sized (1000 MWt) gas cooled fast reactors which can utilize natural uranium as fuel cycle input has been conducted. Gas Cooled Fast Reactor (GFR) is among six types of Generation IV Nuclear Power Plants. GFR with its hard neuron spectrum is superior for closed fuel cycle, and its ability to be operated in high temperature (850 deg. C) makes various options of utilizations become possible. To obtain the capability of consuming natural uranium as fuel cycle input, modified CANDLE burn-up scheme[1-6] is adopted this GFR system by dividing the core into 10 parts of equal volume axially. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 70 W/cc. As an optimization results, a design of 1000 MWt reactors which can be operated 10 years without refueling and fuel shuffling and just need natural uranium as fuel cycle input is discussed. The average discharge burn-up is about 280 GWd/ton HM. Enough margin for criticality was obtained for this reactor.

  7. Maintaining gas cooling equipment

    SciTech Connect

    Rector, J.D.

    1997-05-01

    An often overlooked key to satisfactory operation and longevity of any mechanical device is proper operation and maintenance in accordance with the manufacturer`s written instructions. Absorption chillers, although they use a different technology than the more familiar vapor compression cycle to produce chilled water, operate successfully in a variety of applications if operated and maintained properly. Maintenance procedures may be more frequent than those required for vapor compression chillers, but they are also typically less complex. The goal of this article is to describe the basic operation of an absorption chiller to provide an understanding of the relatively simple tasks required to keep the machine operating at maximum efficiency for its design life and beyond. A good starting point is definitions. Gas cooling equipment is generally defined as alternative energy, non-electric cooling products. This includes absorption chillers, engine-drive chillers and packaged desiccant units, among others. Natural gas combustion drives the equipment.

  8. Evaluation of Hybrid Air-Cooled Flash/Binary Power Cycle

    SciTech Connect

    Greg Mines

    2005-10-01

    Geothermal binary power plants reject a significant portion of the heat removed from the geothermal fluid. Because of the relatively low temperature of the heat source (geothermal fluid), the performance of these plants is quite sensitive to the sink temperature to which heat is rejected. This is particularly true of air-cooled binary plants. Recent efforts by the geothermal industry have examined the potential to evaporatively cool the air entering the air-cooled condensers during the hotter portions of a summer day. While the work has shown the benefit of this concept, air-cooled binary plants are typically located in regions that lack an adequate supply of clean water for use in this evaporative cooling. In the work presented, this water issue is addressed by pre-flashing the geothermal fluid to produce a clean condensate that can be utilized during the hotter portions of the year to evaporatively cool the air. This study examines both the impact of this pre-flash on the performance of the binary plant, and the increase in power output due to the ability to incorporate an evaporative component to the heat rejection process.

  9. Investigation of alternative layouts for the supercritical carbon dioxide Brayton cycle for a sodium-cooled fast reactor.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.

    2009-07-01

    Analyses of supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle performance have largely settled on the recompression supercritical cycle (or Feher cycle) incorporating a flow split between the main compressor downstream of heat rejection, a recompressing compressor providing direct compression without heat rejection, and high and low temperature recuperators to raise the effectiveness of recuperation and the cycle efficiency. Alternative cycle layouts have been previously examined by Angelino (Politecnico, Milan), by MIT (Dostal, Hejzlar, and Driscoll), and possibly others but not for sodium-cooled fast reactors (SFRs) operating at relatively low core outlet temperature. Thus, the present authors could not be sure that the recompression cycle is an optimal arrangement for application to the SFR. To ensure that an advantageous alternative layout has not been overlooked, several alternative cycle layouts have been investigated for a S-CO{sub 2} Brayton cycle coupled to the Advanced Burner Test Reactor (ABTR) SFR preconceptual design having a 510 C core outlet temperature and a 470 C turbine inlet temperature to determine if they provide any benefit in cycle performance (e.g., enhanced cycle efficiency). No such benefits were identified, consistent with the previous examinations, such that attention was devoted to optimizing the recompression supercritical cycle. The effects of optimizing the cycle minimum temperature and pressure are investigated including minimum temperatures and/or pressures below the critical values. It is found that improvements in the cycle efficiency of 1% or greater relative to previous analyses which arbitrarily fixed the minimum temperature and pressure can be realized through an optimal choice of the combination of the minimum cycle temperature and pressure (e.g., for a fixed minimum temperature there is an optimal minimum pressure). However, this leads to a requirement for a larger cooler for heat rejection which may impact the

  10. Economic feasibility and performance study of a solar-powered absorption cycle using some aqueous salt solutions

    SciTech Connect

    Malik, I.H.; Siddiqui, M.A.

    1997-02-01

    Economic analyses of solar collectors, for optimizing generator temperatures in the absorption cycle using aqueous solutions of LiBr, LiBr-ZnBr{sub 2}, LiBr-ZnBr{sub 2}-LiCl, and LiBr-ZnCl{sub 2}-CaBr{sub 2} salts, have been carried out for a wide range of the operating conditions. Ordinary collectors with two glass covers and evacuated-tubular collectors have been selected as the sources of energy for providing hot liquid in the generator of the absorption cycle. Of the four solutions, as the working fluids in the absorption cycles, those having better coefficients of performance are the LiBr/H{sub 2}O at the low evaporator temperatures, and the (LiBr-ZnBr{sub 2}-LiCl)/H{sub 2}O as well as the (LiBr-ZnCl{sub 2}-CaBr{sub 2})/H{sub 2}O at the high evaporator temperatures. Similarly, costs of the solar collectors are low, at low evaporation temperatures for the LiBr/H{sub 2}O and at high temperatures for the other two solutions: the (LiBr-ZnBr{sub 2})/H{sub 2}O, on the other hand, have relatively low COP and high operating costs.

  11. Solar powered absorption cycle heat pump using phase change materials for energy storage

    NASA Technical Reports Server (NTRS)

    Middleton, R. L.

    1972-01-01

    Solar powered heating and cooling system with possible application to residential homes is described. Operating principles of system are defined and illustration of typical energy storage and exchange system is provided.

  12. Steam Generator Component Model in a Combined Cycle of Power Conversion Unit for Very High Temperature Gas-Cooled Reactor

    SciTech Connect

    Oh, Chang H; Han, James; Barner, Robert; Sherman, Steven R

    2007-06-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP), Very High Temperature Gas-Cooled Reactor (VHTR) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. A combined cycle is considered as one of the power conversion units to be coupled to the very high-temperature gas-cooled reactor (VHTR). The combined cycle configuration consists of a Brayton top cycle coupled to a Rankine bottoming cycle by means of a steam generator. A detailed sizing and pressure drop model of a steam generator is not available in the HYSYS processes code. Therefore a four region model was developed for implementation into HYSYS. The focus of this study was the validation of a HYSYS steam generator model of two phase flow correlations. The correlations calculated the size and heat exchange of the steam generator. To assess the model, those calculations were input into a RELAP5 model and its results were compared with HYSYS results. The comparison showed many differences in parameters such as the heat transfer coefficients and revealed the different methods used by the codes. Despite differences in approach, the overall results of heat transfer were in good agreement.

  13. The effect of using a heat recovery absorber on the performance and operating cost of the solar ammonia absorption cycles

    SciTech Connect

    Saghiruddin; Siddiqui, M.A.

    1997-02-01

    Economic analysis of ordinary and evacuated tubular type flat-plate collectors have been carried out for operating absorption cycles with and without heat recovery absorber. Water-ammonia, NaSCN-NH{sub 3} and LiNO{sub 3}-NH{sub 3} have been selected as the working fluids in the cycles. Use of a heat recovery absorber, in addition to the primary absorber in the conventional absorption cycles, lead to improvement in the system performances by about 20--30% in the H{sub 2}O-NH{sub 3} and 33--36% in the NaSCN-NH{sub 3} and LiNO{sub 3}-NH{sub 3} mixtures. Subsequently, there is a considerable amount of reduction in the cost of the solar collector required to operate them. For the set of operating conditions, in this theoretical study, the cost reduces to about 25% in the H{sub 2}O-NH{sub 3} and 30% in the NaSCN and LiNO{sub 3}-NH{sub 3} cycles.

  14. Equatorial ionospheric absorption during half a solar cycle (1964-1970)

    NASA Technical Reports Server (NTRS)

    Gnanalingam, S.

    1972-01-01

    An extensive series of vertical incidence absorption measurements made at an equatorial station is analyzed in detail for a better understanding of the lower ionosphere. A quantitive empirical relationship is derived between absorption and 1 to 8 A solar flux for moderate levels of solar activity. It is shown that the threshold flux for D region modification, at a solar zenith angle of 10 deg, is approximately 0.0005 erg/sq/cm/sec. Attention is drawn to the incidence of days of high absorption even in the absence of solar X-ray activity. Available evidence points to variability of the order of 10 to 40% in the intensity of the solar Lyman alpha radiation as the most likely cause of these unusual, though infrequent, enhancements in absorption.

  15. Integrating district cooling with cogeneration

    SciTech Connect

    Spurr, M.

    1996-11-01

    Chillers can be driven with cogenerated thermal energy, thereby offering the potential to increase utilization of cogeneration throughout the year. However, cogeneration decreases electric output compared to condensing power generation in power plants using a steam cycle (steam turbine or gas turbine combined cycle plants). The foregone electric production increases with increasing temperature of heat recovery. Given a range of conditions for key variables (such as cogeneration utilization, chiller utilization, cost of fuel, value of electricity, value of heat and temperature of heat recovered), how do technology alternatives for combining district cooling with cogeneration compare? This paper summarizes key findings from a report recently published by the International Energy Agency which examines the energy efficiency and economics of alternatives for combining cogeneration technology options (gas turbine simple cycle, diesel engine, steam turbine, gas turbine combined cycle) with chiller options (electric centrifugal, steam turbine centrifugal one-stage steam absorption, two-stage steam absorption, hot water absorption).

  16. Review of the absorption spectra of solid O2 and N2 as they relate to contamination of a cooled infrared telescope

    NASA Technical Reports Server (NTRS)

    Smith, S. M.

    1977-01-01

    During contamination studies for the liquid helium cooled shuttle infrared telescope facility, a literature search was conducted to determine the absorption spectra of the solid state of homonuclear molecules of O2 and N2, and ascertain what laboratory measurements of the solid have been made in the infrared. With the inclusion of one unpublished spectrum, the absorption spectrum of the solid oxygen molecule has been thoroughly studied from visible to millimeter wavelengths. Only two lines appear in the solid that do not also appear in the gas or liquid. A similar result is implied for the solid nitrogen molecule because it also is homonuclear. The observed infrared absorption lines result from lattice modes of the alpha phase of the solid, and disappear at the warmer temperatures of the beta, gamma, and liquid phases. They are not observed from polycrystalline forms of O2, while strong scattering is. Scattering, rather than absorption, is considered to be the principal natural contamination problem for cooled infrared telescopes in low earth orbit.

  17. Hybrid sulfur cycle operation for high-temperature gas-cooled reactors

    SciTech Connect

    Gorensek, Maximilian B

    2015-02-17

    A hybrid sulfur (HyS) cycle process for the production of hydrogen is provided. The process uses a proton exchange membrane (PEM) SO.sub.2-depolarized electrolyzer (SDE) for the low-temperature, electrochemical reaction step and a bayonet reactor for the high-temperature decomposition step The process can be operated at lower temperature and pressure ranges while still providing an overall energy efficient cycle process.

  18. Study of a Vuilleumier cycle cryogenic refrigerator for detector cooling on the limb scanning infrared radiometer

    NASA Technical Reports Server (NTRS)

    Russo, S. C.

    1976-01-01

    A program to detect and monitor the presence of trace constituents in the earth's atmosphere by using the Limb Scanning Infrared Radiometer (LSIR) is reported. The LSIR, which makes radiometric measurements of the earth's limb radiance profile from a space platform, contains a detector assembly that must be cooled to a temperature of 65 + or - 2 K. The feasibility of cooling the NASA-type detector package with Vuilleumier (VM) cryogenic refrigerator was investigated to develop a preliminary conceptual design of a VM refrigerator that is compatible with a flight-type LSIR instrument. The scope of the LSIR program consists of analytical and design work to establish the size, weight, power consumption, interface requirements, and other important characteristics of a cryogenic cooler that would meet the requirements of the LSIR. The cryogenic cooling requirements under the conditions that NASA specified were defined. Following this, a parametric performance analysis was performed to define the interrelationships between refrigeration characteristics and mission requirements. This effort led to the selection of an optimum refrigerator design for the LSIR mission.

  19. Photochromic cycle of 2'-hydroxyacetophenone azine studied by absorption and emission spectroscopy in different solvents

    NASA Astrophysics Data System (ADS)

    Filipczak, Katarzyna; Karolczak, Jerzy; Lipkowski, Pawel; Filarowski, Aleksander; Ziółek, Marcin

    2013-09-01

    This paper reports on the investigations of the synthesized di-(o-hydroxyaryl ketoimine) compound by the steady state absorption and emission techniques as well as picosecond time resolved emission and femtosecond transient absorption methods in different solvents. The results of the experimental observation have been supported by the theoretical DFT and TD-DFT calculations. The theoretical data have revealed the completed influence of the environmental polarity on particular conformers of studied compound. Dependencies between the activation rate constant and polarizability function as well as Kamlet-Abbond-Taft hydrogen-bonding parameter have been obtained in different solvent. The mechanism of photodynamic changes of di-(o-hydroxyaryl ketoimine) is presented.

  20. Design and experimental testing of the performance of an outdoor LiBr/H{sub 2}O solar thermal absorption cooling system with a cold store

    SciTech Connect

    Agyenim, Francis; Knight, Ian; Rhodes, Michael

    2010-05-15

    A domestic-scale prototype experimental solar cooling system has been developed based on a LiBr/H{sub 2}O absorption system and tested during the 2007 summer and autumn months in Cardiff University, UK. The system consisted of a 12 m{sup 2} vacuum tube solar collector, a 4.5 kW LiBr/H{sub 2}O absorption chiller, a 1000 l cold storage tank and a 6 kW fan coil. The system performance, as well as the performances of the individual components in the system, were evaluated based on the physical measurements of the daily solar radiation, ambient temperature, inlet and outlet fluid temperatures, mass flow rates and electrical consumption by component. The average coefficient of thermal performance (COP) of the system was 0.58, based on the thermal cooling power output per unit of available thermal solar energy from the 12 m{sup 2} Thermomax DF100 vacuum tube collector on a hot sunny day with average peak insolation of 800 W/m{sup 2} (between 11 and 13.30 h) and ambient temperature of 24 C. The system produced an electrical COP of 3.6. Experimental results prove the feasibility of the new concept of cold store at this scale, with chilled water temperatures as low as 7.4 C, demonstrating its potential use in cooling domestic scale buildings. (author)

  1. Experiences in solar cooling systems

    NASA Astrophysics Data System (ADS)

    Ward, D. S.

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

  2. Development of solar driven absorption air conditioners and heat pumps

    NASA Astrophysics Data System (ADS)

    Dao, K.; Wahlig, M.; Wali, E.; Rasson, J.; Molishever, E.

    1980-03-01

    The development of absorption refrigeration systems for solar active heating and cooling applications is discussed. The approaches investigated are those using air-cooled condenser-absorber and those leading to coefficient of performances (COP) that increase continuously with heat source temperature. This is primarily an experimental project, with the emphasis on designing, fabricating and testing absorption chillers in operating regimes that are particularly suited for solar energy applications. Its demonstrated that the conventional single-effect ammonia-water absorption cycle can be used (with minor modifications) for solar cooling.

  3. Fuel Cycle System Analysis Implications of Sodium-Cooled Metal-Fueled Fast Reactor Transuranic Conversion Ratio

    SciTech Connect

    Steven J. Piet; Edward A. Hoffman; Samuel E. Bays; Gretchen E. Matthern; Jacob J. Jacobson; Ryan Clement; David W. Gerts

    2013-03-01

    If advanced fuel cycles are to include a large number of fast reactors (FRs), what should be the transuranic (TRU) conversion ratio (CR)? The nuclear energy era started with the assumption that they should be breeder reactors (CR > 1), but the full range of possible CRs eventually received attention. For example, during the recent U.S. Global Nuclear Energy Partnership program, the proposal was burner reactors (CR < 1). Yet, more recently, Massachusetts Institute of Technology's "Future of the Nuclear Fuel Cycle" proposed CR [approximately] 1. Meanwhile, the French company EDF remains focused on breeders. At least one of the reasons for the differences of approach is different fuel cycle objectives. To clarify matters, this paper analyzes the impact of TRU CR on many parameters relevant to fuel cycle systems and therefore spans a broad range of topic areas. The analyses are based on a FR physics parameter scan of TRU CR from 0 to [approximately]1.8 in a sodium-cooled metal-fueled FR (SMFR), in which the fuel from uranium-oxide-fueled light water reactors (LWRs) is recycled directly to FRs and FRs displace LWRs in the fleet. In this instance, the FRs are sodium cooled and metal fueled. Generally, it is assumed that all TRU elements are recycled, which maximizes uranium ore utilization for a given TRU CR and waste radiotoxicity reduction and is consistent with the assumption of used metal fuel separated by electrochemical means. In these analyses, the fuel burnup was constrained by imposing a neutron fluence limit to fuel cladding to the same constant value. This paper first presents static, time-independent measures of performance for the LWR [right arrow] FR fuel cycle, including mass, heat, gamma emission, radiotoxicity, and the two figures of merit for materials for weapon attractiveness developed by C. Bathke et al. No new fuel cycle will achieve a static equilibrium in the foreseeable future. Therefore, additional analyses are shown with dynamic, time

  4. Performance evaluation of a solar ejector-vapour compression cycle for cooling application

    NASA Astrophysics Data System (ADS)

    Megdouli, K.; Elakhdar, M.; Nahdi, E.; Kairouani, L.; Mhimid, A.

    2015-04-01

    This study deals with the performance of the ejector-vapour compression cycle assisted by solar. The effect of operating conditions on the combined cycle performance is examined. Also, a comparison of the system performance with environment friendly refrigerants (R134a, R600, R123, R141b, R142b, R152a, R290, and R245fa) is made. This performance is calculated using an empirical correlation. Thermodynamic properties of functioning fluids are obtained with package REFPROP 8. Using the typical meteorological year file containing the weather data of the city of Tunis, the system performance is computed for three collector types. The theoretical results show that the R290 offers the highest coefficient of performance, COP=3.75, for generator temperature TB = 78°C, condenser temperature Tc = 30°C and the intercooler temperature Te = 15°C.

  5. Stirling cycle heat pump for heating and/or cooling systems

    SciTech Connect

    Meijer, R.J.; Khalili, K.; Meijer, E.; Godett, T.M.

    1991-03-05

    This patent describes a duplex Stirling cycle machine acting as a heat pump. It comprises: a Stirling engine having pistons axially displaceable within parallel cylinders, the engine further having a swashplate rotatable about an axis of, rotation parallel to the cylinders and defining a plane inclined from the axis of rotation. The pistons connected to the swashplate via crossheads whereby axial displacement of the pistons is converted to rotation of the swashplate, and a Stirling cycle heat pump having a compression heat exchanger, an expansion heat exchanger and a regenerator with pistons equal in number to the engine pistons and axially displaceable within cylinders which are oriented co-axially with the engine cylinders. The crossheads further connected to the heat pump pistons whereby the heat pump pistons move simultaneously with the engine pistons over an equal stroke distance.

  6. Numerical Hydraulic Study on Seawater Cooling System of Combined Cycle Power Plant

    NASA Astrophysics Data System (ADS)

    Kim, J. Y.; Park, S. M.; Kim, J. H.; Kim, S. W.

    2010-06-01

    As the rated flow and pressure increase in pumping facilities, a proper design against surges and severe cavitations in the pipeline system is required. Pressure surge due to start-up, shut-down process and operation failure causes the water hammer in upstream of the closing valve and the cavitational hammer in downstream of the valve. Typical cause of water hammer is the urgent closure of valves by breakdown of power supply and unexpected failure of pumps. The abrupt changes in the flow rate of the liquid results in high pressure surges in upstream of the valves, thus kinetic energy is transformed into potential energy which leads to the sudden increase of the pressure that is called as water hammer. Also, by the inertia, the liquid continues to flow downstream of the valve with initial speed. Accordingly, the pressure decreases and an expanding vapor bubble known as column separation are formed near the valve. In this research, the hydraulic study on the closed cooling water heat exchanger line, which is the one part of the power plant, is introduced. The whole power plant consists of 1,200 MW combined power plant and 220,000 m3/day desalination facility. Cooling water for the plant is supplied by sea water circulating system with a capacity of 29 m3/s. The primary focus is to verify the steady state hydraulic capacity of the system. The secondary is to quantify transient issues and solutions in the system. The circuit was modeled using a commercial software. The stable piping network was designed through the hydraulic studies using the simulation for the various scenarios.

  7. Apparatus and methods of reheating gas turbine cooling steam and high pressure steam turbine exhaust in a combined cycle power generating system

    DOEpatents

    Tomlinson, Leroy Omar; Smith, Raub Warfield

    2002-01-01

    In a combined cycle system having a multi-pressure heat recovery steam generator, a gas turbine and steam turbine, steam for cooling gas turbine components is supplied from the intermediate pressure section of the heat recovery steam generator supplemented by a portion of the steam exhausting from the HP section of the steam turbine, steam from the gas turbine cooling cycle and the exhaust from the HP section of the steam turbine are combined for flow through a reheat section of the HRSG. The reheated steam is supplied to the IP section inlet of the steam turbine. Thus, where gas turbine cooling steam temperature is lower than optimum, a net improvement in performance is achieved by flowing the cooling steam exhausting from the gas turbine and the exhaust steam from the high pressure section of the steam turbine in series through the reheater of the HRSG for applying steam at optimum temperature to the IP section of the steam turbine.

  8. High cycle fatigue behavior of Incoloy 800H in a simulated high-temperature gas-cooled reactor helium environment

    SciTech Connect

    Soo, P.; Sabatini, R.L.; Epel, L.G.; Hare, J.R. Sr.

    1980-01-01

    The current study was an attempt to evaluate the high cycle fatigue strength of Incoloy 800H in a High-Temperature Gas-Cooled Reactor helium environment containing significant quantities of moisture. As-heat-treated and thermally-aged materials were tested to determine the effects of long term corrosion in the helium test gas. Results from in-helium tests were compared to those from a standard air environment. It was found that the mechanisms of fatigue failure were very complex and involved recovery/recrystallization of the surface ground layer on the specimens, sensitization, hardness changes, oxide scale integrity, and oxidation at the tips of propagation cracks. For certain situations a corrosion-fatigue process seems to be controlling. However, for the helium environment studied, there was usually no aging or test condition for which air gave a higher fatigue strength.

  9. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Sawicki, Jerzy T.

    2003-01-01

    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

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

    SciTech Connect

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

    2007-01-01

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

  11. What Dominates the Coronal Emission Spectrum During the Cycle of Impulsive Heating and Cooling?

    NASA Technical Reports Server (NTRS)

    Bradshaw, Stephen J.; Klimchuk, James A.

    2011-01-01

    The smoking gun of small-scale, impulsive events heating the solar corona is expected to be the presence of a hot ( > 5 MK) plasma component. Evidence for this has been scarce, but has gradually begun to accumulate due to recent studies designed to constrain the high temperature part of the emission measure distribution. However, the detected hot component is often weaker than models predict and this is due in part to the common modeling assumption that the ionization balance remains in equilibrium. The launch of the latest generation of space-based observing instrumentation aboard Hinode and the Solar Dynamics Observatory (SDO) has brought the matter of the ionization state of the plasma firmly to the forefront. It is timely to consider exactly what emission current instruments would detect when observing a corona heated impulsively on small-scales by nanoflares. Only after we understand the full effects of nonequilibrium ionization can we draw meaningful conclusions about the plasma that is (or is not) present. We have therefore performed a series of hydrodynamic simulations for a variety of different nanoflare properties and initial conditions. Our study has led to several key conclusions. 1. Deviations from equilibrium are greatest for short-duration nanoflares at low initial coronal densities. 2. Hot emission lines are the most affected and are suppressed sometimes to the point of being invisible. 3. The emission detected in all of the SDO-AIA channels is generally dominated by warm, over-dense, cooling plasma. 4. It is difficult not to create coronal loops that emit strongly at 1.5 MK and in the range 2 to 5 MK, which are the most commonly observed kind, for a broad range of nanoflare scenarios. 5. The Fe XV (284.16 ) emission in most of our models is about 10 times brighter than the Ca XVII (192.82 ) emission, consistent with observations. Our overarching conclusion is that small-scale, impulsive heating inducing a nonequilibrium ionization state leads to

  12. High-Temperature Gas-Cooled Reactor Steam Cycle/Cogeneration Lead Project strategy plan

    SciTech Connect

    1982-03-01

    The strategy for developing the HTGR system and introducing it into the energy marketplace is based on using the most developed technology path to establish a HTGR-Steam Cycle/Cogeneration (SC/C) Lead Project. Given the status of the HTGR-SC/C technology, a Lead Plant could be completed and operational by the mid 1990s. While there is remaining design and technology development that must be accomplished to fulfill technical and licensing requirements for a Lead Project commitment, the major barriers to the realization a HTGR-SC/C Lead Project are institutional in nature, e.g. Project organization and management, vendor/supplier development, cost/risk sharing between the public and private sector, and Project financing. These problems are further exacerbated by the overall pervading issues of economic and regulatory instability that presently confront the utility and nuclear industries. This document addresses the major institutional issues associated with the HTGR-SC/C Lead Project and provides a starting point for discussions between prospective Lead Project participants toward the realization of such a Project.

  13. Doubling the electrocaloric cooling of poled ferroelectric materials by bipolar cycling

    NASA Astrophysics Data System (ADS)

    Basso, Vittorio; Gerard, Jean-François; Pruvost, Sébastien

    2014-08-01

    We have investigated the entropy change in the ferroelectric phase of poly(vinylidene fluoride-trifluoroethylene) 70/30 films by direct heat flux calorimetry using Peltier cell heat flux sensors. We find that by applying a negative electric field to a positively poled state, the entropy can be further increased without any significantly change of the remanent polarization or the domain structure. By cycling between positive and negative values of the electric field, the electrocaloric effect (ECE) can be then improved by a factor of 2. As an example, we measured, around the positive remanence Pr = 60 × 10-3 C m-2, a fully reversible entropy change |Δs| = 1 J kg-1K-1 for a field change from 40 × 106 to -40 × 106 V m-1 and a maximum of |Δs| = 3.2 J kg-1K-1 for an asymmetric field change from 200 × 106 to -40 × 106 V m-1. This effect can be exploited to significantly increase the range of operating temperature for ECE materials below their Curie temperature.

  14. Energy Absorption in a Load-Unload Cycle of Knee Implant Using Fractal Model of Rough Surfaces

    NASA Astrophysics Data System (ADS)

    Hodaei, Mohammad; Farhang, Kambiz

    2016-05-01

    Roughness measurement of knee implant surfaces is investigated. The study of roughness measurement show that the topography of knee implant surface is multi-scale and surface spectra follows a power law behavior. A magnification of rough surface topography implies that there is no difference between original and magnified profile of implant surface. For implant surface, statistical parameters such as variance of height, curvature, and slope are found to be scale-dependent. Fractal representation of implant surface shows that the size-distribution of the multi-scale contacts spots follows a power law and is characterized by the fractal dimension of implant surface. Fractal surface description of the rough surfaces of knee implant is used to obtain force-displacement relationship of the contact force. Using an approximate function through the fusion of two piecewise functions, energy absorption of a knee implant in a single cycle of load-unload is obtained.

  15. An examination of the proposition to use membrane transport in an aqueous solution absorption heat pump cycle

    NASA Astrophysics Data System (ADS)

    Yu, J. S.; Haskin, W. L.; Chang, W. S.

    1990-06-01

    A thermal transfer cycle utilizing membrane osmotic transport of water against a pressure rise is investigated from the viewpoint of the operation of a conventional absorption heat pump using an aqueous solution as the working fluid. Physical sorption, similar or equivalent to condensation, of water vapor in the membrane material is considered to be an essential step in the overall process of water transport. The thermal nature of this step during which the heat of sorption similar in amount to the heat of condensation for water vapor must evolve at the evaporator temperature or lower disqualifies the system in performance as a heat pump. Simple flow relations for the aqueous sugar solution are derived under simplifying assumptions. A set of numerical calculations is given as an illustration to show that the inferred steps are well within the limits of thermodynamics.

  16. Physical and Perceptual Cooling with Beverages to Increase Cycle Performance in a Tropical Climate

    PubMed Central

    Riera, Florence; Trong, Than Tran; Sinnapah, Stéphane; Hue, Olivier

    2014-01-01

    Purpose This study compares the effects of neutral temperature, cold and ice-slush beverages, with and without 0.5% menthol on cycling performance, core temperature (Tco) and stress responses in a tropical climate (hot and humid conditions). Methods Twelve trained male cyclists/triathletes completed six 20-km exercise trials against the clock in 30.7°C±0.8°C and 78%±0.03% relative humidity. Before and after warm-up, and before exercise and every 5 km during exercise, athletes drank 190 mL of either aromatized (i.e., with 0.5 mL of menthol (5 gr/L)) or a non-aromatized beverage (neutral temperature: 23°C±0.1°C, cold: 3°C±0.1°C, or ice-slush: −1°C±0.7°C). During the trials, heart rate (HR) was continuously monitored, whereas core temperature (Tco), thermal comfort (TC), thermal sensation (TS) and rate of perceived exertion (RPE) were measured before and after warm-up, every 5 km of exercise, and at the end of exercise and after recovery. Results Both the beverage aroma (P<0.02) and beverage temperature (P<0.02) had significant and positive effects on performance, which was considerably better with ice-slush than with a neutral temperature beverage, whatever the aroma (P<0.002), and with menthol vs non-menthol (P<0.02). The best performances were obtained with ice-slush/menthol and cold/menthol, as opposed to neutral/menthol. No differences were noted in HR and Tco between trials. Conclusion Cold water or ice-slush with menthol aroma seems to be the most effective beverage for endurance exercise in a tropical climate. Further studies are needed to explore its effects in field competition. PMID:25084009

  17. Investigation of the Performance of D2O-Cooled High-Conversion Reactors for Fuel Cycle Calculations

    SciTech Connect

    Hikaru Hiruta; Gilles Youinou

    2013-09-01

    This report presents FY13 activities for the analysis of D2O cooled tight-pitch High-Conversion PWRs (HCPWRs) with U-Pu and Th-U fueled cores aiming at break-even or near breeder conditions while retaining the negative void reactivity. The analyses are carried out from several aspects which could not be covered in FY12 activities. SCALE 6.1 code system is utilized, and a series of simple 3D fuel pin-cell models are developed in order to perform Monte Carlo based criticality and burnup calculations. The performance of U-Pu fueled cores with axial and internal blankets is analyzed in terms of their impact on the relative fissile Pu mass balance, initial Pu enrichment, and void coefficient. In FY12, Pu conversion performances of D2O-cooled HCPWRs fueled with MOX were evaluated with small sized axial/internal DU blankets (approximately 4cm of axial length) in order to ensure the negative void reactivity, which evidently limits the conversion performance of HCPWRs. In this fiscal year report, the axial sizes of DU blankets are extended up to 30 cm in order to evaluate the amount of DU necessary to reach break-even and/or breeding conditions. Several attempts are made in order to attain the milestone of the HCPWR designs (i.e., break-even condition and negative void reactivity) by modeling of HCPWRs under different conditions such as boiling of D2O coolant, MOX with different 235U enrichment, and different target burnups. A similar set of analyses are performed for Th-U fueled cores. Several promising characteristics of 233U over other fissile like 239Pu and 235U, most notably its higher fission neutrons per absorption in thermal and epithermal ranges combined with lower ___ in the fast range than 239Pu allows Th-U cores to be taller than MOX ones. Such an advantage results in 4% higher relative fissile mass balance than that of U-Pu fueled cores while retaining the negative void reactivity until the target burnup of 51 GWd/t. Several other distinctions between U-Pu and

  18. Laser cooling of Er3+-doped solids

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2010-10-01

    We consider theoretically a mechanism for laser cooling in rare-earth-doped low-phonon materials based simultaneously on two cooling cycles: a traditional cooling cycle with an anti-Stokes fluorescence transition as well as an infrared-to-visible upconversion cycle, to overcome the self-termination effects in either anti-Stokes or upconversion cooling on its own. Our simulations, performed for erbium-doped potassium-lead chloride crystal ( Er3+:KPl 2Cl 5) known to be an extremely low phonon energy host, uses two pump wavelengths corresponding to the long wavelength tails of the absorption spectra of the 4I15/2 → 4I13/2 and 4I15/2 → 4I9/2 transitions. The contribution of each pump source to the cooling process is comprehensively investigated. We show that, although the energy gap between 4I15/2 and 4I9/2 levels exceeds the energy gap between 4I15/2 and 4I13/2 levels and cooling process is more efficient with the cycle based on the 4I15/2 → 4I13/2 transition, the second cooling cycle based on the 4I15/2 → 4I9/2 transition can be used as a supplementary one.

  19. An Active Broad Area Cooling Model of a Cryogenic Propellant Tank with a Single Stage Reverse Turbo-Brayton Cycle Cryocooler

    NASA Technical Reports Server (NTRS)

    Guzik, Monica C.; Tomsik, Thomas M.

    2011-01-01

    As focus shifts towards long-duration space exploration missions, an increased interest in active thermal control of cryogenic propellants to achieve zero boil-off of cryogens has emerged. An active thermal control concept of considerable merit is the integration of a broad area cooling system for a cryogenic propellant tank with a combined cryocooler and circulator system that can be used to reduce or even eliminate liquid cryogen boil-off. One prospective cryocooler and circulator combination is the reverse turbo-Brayton cycle cryocooler. This system is unique in that it has the ability to both cool and circulate the coolant gas efficiently in the same loop as the broad area cooling lines, allowing for a single cooling gas loop, with the primary heat rejection occurring by way of a radiator and/or aftercooler. Currently few modeling tools exist that can size and characterize an integrated reverse turbo-Brayton cycle cryocooler in combination with a broad area cooling design. This paper addresses efforts to create such a tool to assist in gaining a broader understanding of these systems, and investigate their performance in potential space missions. The model uses conventional engineering and thermodynamic relationships to predict the preliminary design parameters, including input power requirements, pressure drops, flow rate, cycle performance, cooling lift, broad area cooler line sizing, and component operating temperatures and pressures given the cooling load operating temperature, heat rejection temperature, compressor inlet pressure, compressor rotational speed, and cryogenic tank geometry. In addition, the model allows for the preliminary design analysis of the broad area cooling tubing, to determine the effect of tube sizing on the reverse turbo-Brayton cycle system performance. At the time this paper was written, the model was verified to match existing theoretical documentation within a reasonable margin. While further experimental data is needed for full

  20. Design and Economic Potential of an Integrated High-Temperature Fuel Cell and Absorption Chiller Combined Cooling, Heat, and Power System

    NASA Astrophysics Data System (ADS)

    Hosford, Kyle S.

    Clean distributed generation power plants can provide a much needed balance to our energy infrastructure in the future. A high-temperature fuel cell and an absorption chiller can be integrated to create an ideal combined cooling, heat, and power system that is efficient, quiet, fuel flexible, scalable, and environmentally friendly. With few real-world installations of this type, research remains to identify the best integration and operating strategy and to evaluate the economic viability and market potential of this system. This thesis informs and documents the design of a high-temperature fuel cell and absorption chiller demonstration system at a generic office building on the University of California, Irvine (UCI) campus. This work details the extension of prior theoretical work to a financially-viable power purchase agreement (PPA) with regard to system design, equipment sizing, and operating strategy. This work also addresses the metering and monitoring for the system showcase and research and details the development of a MATLAB code to evaluate the economics associated with different equipment selections, building loads, and economic parameters. The series configuration of a high-temperature fuel cell, heat recovery unit, and absorption chiller with chiller exhaust recirculation was identified as the optimal system design for the installation in terms of efficiency, controls, ducting, and cost. The initial economic results show that high-temperature fuel cell and absorption chiller systems are already economically competitive with utility-purchased generation, and a brief case study of a southern California hospital shows that the systems are scalable and viable for larger stationary power applications.

  1. Helium heater design for the helium direct cycle component test facility. [for gas-cooled nuclear reactor power plant

    NASA Technical Reports Server (NTRS)

    Larson, V. R.; Gunn, S. V.; Lee, J. C.

    1975-01-01

    The paper describes a helium heater to be used to conduct non-nuclear demonstration tests of the complete power conversion loop for a direct-cycle gas-cooled nuclear reactor power plant. Requirements for the heater include: heating the helium to a 1500 F temperature, operating at a 1000 psia helium pressure, providing a thermal response capability and helium volume similar to that of the nuclear reactor, and a total heater system helium pressure drop of not more than 15 psi. The unique compact heater system design proposed consists of 18 heater modules; air preheaters, compressors, and compressor drive systems; an integral control system; piping; and auxiliary equipment. The heater modules incorporate the dual-concentric-tube 'Variflux' heat exchanger design which provides a controlled heat flux along the entire length of the tube element. The heater design as proposed will meet all system requirements. The heater uses pressurized combustion (50 psia) to provide intensive heat transfer, and to minimize furnace volume and heat storage mass.

  2. Development of Exhaust Gas Driven Absorption Chiller-Heater

    NASA Astrophysics Data System (ADS)

    Inoue, Naoyuki; Endou, Tetsuya; Saito, Kiyoshi; Kawai, Sunao

    Waste heat from co-generation systems are usually recovered by hot water or steam, those are used to drive absorption refrigerators at cooling time, and those are used for heating via heat exchangers at heating time. However waste heat from micro gas turbines are discharged in the form of exhaust gas, it is simple that exhaust gas is directly supplied to absorption chiller-heaters. In the first report we studied cooling cycle, and this second paper, we evaluated various absorption heating cycles for exhaust gas driven absorption chiller-heaters, and adopted one of these cycles for the prototype machine. Also, we experimented with the prototype for wide range condition and got the heating characteristics. Based on the experimental data, we developed a simulation model of the static characteristics, and then studied how to increase the output by limited exhaust gas.

  3. Low-cost, heated, and/or cooled flow-through cell for transmission x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Jentoft, R. E.; Deutsch, S. E.; Gates, B. C.

    1996-06-01

    A transmission x-ray absorption spectroscopy cell that can be used for air-sensitive samples with in situ treatment is described. The cell is designed with a relatively small size for use with air-sensitive powdered catalyst samples that must be loaded in a glove box. Samples can be treated in situ with gas flow or vacuum and temperature control up to 500 °C. The cell is constructed of stainless steel and designed for durability as well as ease of repair. The cells are vacuum tight and equipped with beryllium windows sealed with vacuum O-ring flanges for easy loading. Each cell, with all parts excluding the windows, costs about 2700.

  4. Towards elucidating the energy of the first excited singlet state of xanthophyll cycle pigments by X-ray absorption spectroscopy.

    PubMed

    Gruszecki, W I; Stiel, H; Niedzwiedzki, D; Beck, M; Milanowska, J; Lokstein, H; Leupold, D

    2005-06-01

    The first excited singlet state (S(1)) of carotenoids (also termed 2A(g)(-)) plays a key role in photosynthetic excitation energy transfer due to its close proximity to the S(1) (Q(y)) level of chlorophylls. The determination of carotenoid 2A(g)(-) energies by optical techniques is difficult; transitions from the ground state (S(0), 1A(g)(-)) to the 2A(g)(-) state are forbidden ("optically dark") due to parity (g <-- //--> g) as well as pseudo-parity selection rules (- <-- //--> -). Of particular interest are S(1) energies of the so-called xanthophyll-cycle pigments (violaxanthin, antheraxanthin and zeaxanthin) due to their involvement in photoprotection in plants. Previous determinations of S(1) energies of violaxanthin and zeaxanthin by different spectroscopic techniques vary considerably. Here we present an alternative approach towards elucidation of the optically dark states of xanthophylls by near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The indication of at least one pi* energy level (about 0.5 eV below the lowest 1B(u)(+) vibronic sublevel) has been found for zeaxanthin. Present limitations and future improvements of NEXAFS to study optically dark states of carotenoids are discussed. NEXAFS combined with simultaneous optical pumping will further aid the investigation of these otherwise hardly accessible states. PMID:15949988

  5. Rapid freeze-drying cycle optimization using computer programs developed based on heat and mass transfer models and facilitated by tunable diode laser absorption spectroscopy (TDLAS).

    PubMed

    Kuu, Wei Y; Nail, Steven L

    2009-09-01

    Computer programs in FORTRAN were developed to rapidly determine the optimal shelf temperature, T(f), and chamber pressure, P(c), to achieve the shortest primary drying time. The constraint for the optimization is to ensure that the product temperature profile, T(b), is below the target temperature, T(target). Five percent mannitol was chosen as the model formulation. After obtaining the optimal sets of T(f) and P(c), each cycle was assigned with a cycle rank number in terms of the length of drying time. Further optimization was achieved by dividing the drying time into a series of ramping steps for T(f), in a cascading manner (termed the cascading T(f) cycle), to further shorten the cycle time. For the purpose of demonstrating the validity of the optimized T(f) and P(c), four cycles with different predicted lengths of drying time, along with the cascading T(f) cycle, were chosen for experimental cycle runs. Tunable diode laser absorption spectroscopy (TDLAS) was used to continuously measure the sublimation rate. As predicted, maximum product temperatures were controlled slightly below the target temperature of -25 degrees C, and the cascading T(f)-ramping cycle is the most efficient cycle design. In addition, the experimental cycle rank order closely matches with that determined by modeling. PMID:19504575

  6. Heat-activated cooling devices: A guidebook for general audiences

    SciTech Connect

    Wiltsee, G.

    1994-02-01

    Heat-activated cooling is refrigeration or air conditioning driven by heat instead of electricity. A mill or processing facility can us its waste fuel to air condition its offices or plant; using waste fuel in this way can save money. The four basic types of heat-activated cooling systems available today are absorption cycle, desiccant system, steam jet ejector, and steam turbine drive. Each is discussed, along with cool storage and biomass boilers. Steps in determining the feasibility of heat-activated cooling are discussed, as are biomass conversion, system cost and integration, permits, and contractor selection. Case studies are given.

  7. Effect of thermal barrier coatings on the performance of steam and water-cooled gas turbine/steam turbine combined cycle system

    NASA Technical Reports Server (NTRS)

    Nainiger, J. J.

    1978-01-01

    An analytical study was made of the performance of air, steam, and water-cooled gas-turbine/steam turbine combined-cycle systems with and without thermal-barrier coatings. For steam cooling, thermal barrier coatings permit an increase in the turbine inlet temperature from 1205 C (2200 F), resulting in an efficiency improvement of 1.9 percentage points. The maximum specific power improvement with thermal barriers is 32.4 percent, when the turbine inlet temperature is increased from 1425 C (2600 F) to 1675 C (3050 F) and the airfoil temperature is kept the same. For water cooling, the maximum efficiency improvement is 2.2 percentage points at a turbine inlet temperature of 1683 C (3062 F) and the maximum specific power improvement is 36.6 percent by increasing the turbine inlet temperature from 1425 C (2600 F) to 1730 C (3150 F) and keeping the airfoil temperatures the same. These improvements are greater than that obtained with combined cycles using air cooling at a turbine inlet temperature of 1205 C (2200 F). The large temperature differences across the thermal barriers at these high temperatures, however, indicate that thermal stresses may present obstacles to the use of coatings at high turbine inlet temperatures.

  8. Preliminary Investigations on Therapy Thresholds for Laser Dosimetry, Cryogen Spray Cooling Duration, and Treatment Cycles for Laser Cartilage Reshaping in the New Zealand White Rabbit Auricle

    PubMed Central

    Chlebicki, Cara A.; Protsenko, Dmitry E.; Wong, Brian J.

    2014-01-01

    Previous studies have demonstrated the feasibility of laser irradiation (λ=1.45 μm) in tandem with cryogen spray cooling (CSC) to reshape rabbit auricular cartilage using total energy density of 14 J/cm2. The aim of this study was to further explore and identify the dosimetry parameter space for laser output energy, CSC duration, and treatment cycles required to achieve shape change while limiting skin and cartilage injury. Ten New Zealand white rabbits were treated with the 1.45 μm diode laser combined with cryogen spray cooling (Candela Smoothbeam™, Candela Co., Wayland, MA). The ear's central portion was bent around a cylindrical jig and irradiated in consecutive spots of 6 mm diameter (13 J/cm2 or 14 J/cm2 per spot) along 3 rows encompassing the bend. CSC was delivered during irradiation in cycles consisting of 25-35 ms. At thin and thick portions of the ear, 4-7 and 6-10 treatment cycles were delivered, respectively. After surgery, ears were examined and splinted for 6 weeks. Treatment parameters resulting in acceptable (Grades 1 & 2) and unacceptable (Grade 3) skin injuries for thick and thin regions were identified and shape change was observed. Confocal and histological analysis of cartilage tissue revealed several outcomes correlating to laser dosimetry, CSC duration, and treatment cycles. These outcomes included expansion of cartilage layers (thickening), partial cartilage injuries, and full thickness cartilage injuries. We determined therapy thresholds for laser output energy, cryogen spray cooling duration, and treatment cycles in the rabbit auricular model. These parameters are a starting point for future clinical procedures aimed at correcting external ear deformities. PMID:24202858

  9. Thermodynamic study of air-cycle and mercury-vapor-cycle systems for refrigerating cooling air for turbines or other components

    NASA Technical Reports Server (NTRS)

    Nachtigall, Alfred J; Freche, John C; Esgar, Jack B

    1956-01-01

    An analysis of air refrigeration systems indicated that air cycles are generally less satisfactory than simple heat exchangers unless high component efficiencies and high values of heat-exchanger effectiveness can be obtained. A system employing a mercury-vapor cycle appears to be feasible for refrigerating air that must enter the system at temperature levels of approximately 1500 degrees R, and this cycle is more efficient than the air cycle. Weight of the systems was not considered. The analysis of the systems is presented in a generalized dimensionless form.

  10. SOLERAS - Saudi University Solar Cooling Laboratories Project. Final report, project summary

    SciTech Connect

    Not Available

    1986-01-01

    Proposals for research on solar cooling are presented for four Saudi Arabian universities. The universities are the University of Petroleum and Minerals in Dhahran, King Saud University in Riyadh, King Abdulaziz University in Jeddah, and King Faisal University in Dammam. Topics researched include the Rankine cycle, passive solar cooling systems, a solar-powered lithium bromide-water absorption machine and a photovoltaic-powered thermoelectric cooling machine. (BCS)

  11. Numerical and experimental analysis of a thin liquid film on a rotating disk related to development of a spacecraft absorption cooling system

    NASA Technical Reports Server (NTRS)

    Faghri, Amir; Swanson, Theodore D.

    1989-01-01

    The numerical and experimental analysis of a thin liquid film on a rotating and a stationary disk related to the development of an absorber unit for a high capacity spacecraft absorption cooling system, is described. The creation of artificial gravity by the use of a centrifugal field was focused upon in this report. Areas covered include: (1) One-dimensional computation of thin liquid film flows; (2) Experimental measurement of film height and visualization of flow; (3) Two-dimensional computation of the free surface flow of a thin liquid film using a pressure optimization method; (4) Computation of heat transfer in two-dimensional thin film flow; (5) Development of a new computational methodology for the free surface flows using a permeable wall; (6) Analysis of fluid flow and heat transfer in a thin film in the presence and absence of gravity; and (7) Comparison of theoretical prediction and experimental data. The basic phenomena related to fluid flow and heat transfer on rotating systems reported here can also be applied to other areas of space systems.

  12. Coordinated optimization of the parameters of the cooled gas-turbine flow path and the parameters of gas-turbine cycles and combined-cycle power plants

    NASA Astrophysics Data System (ADS)

    Kler, A. M.; Zakharov, Yu. B.; Potanina, Yu. M.

    2014-06-01

    In the present paper, we evaluate the effectiveness of the coordinated solution to the optimization problem for the parameters of cycles in gas turbine and combined cycle power plants and to the optimization problem for the gas-turbine flow path parameters within an integral complex problem. We report comparative data for optimizations of the combined cycle power plant at coordinated and separate optimizations, when, first, the gas turbine and, then, the steam part of a combined cycle plant is optimized. The comparative data are presented in terms of economic indicators, energy-effectiveness characteristics, and specific costs. Models that were used in the present study for calculating the flow path enable taking into account, as a factor influencing the economic and energy effectiveness of the power plant, the heat stability of alloys from which the nozzle and rotor blades of gas-turbine stages are made.

  13. Feasibility study on ultralong-cycle operation and material performance for compact liquid metal-cooled fast reactors: a review work

    SciTech Connect

    Tak, Taewoo; Choe, Jiwon; Jeong, Yongjin; Lee, Deokjung; Kim, T. K.; Hong, Ser Gi

    2015-11-01

    This paper reviews the feasibility of ultralong-cycle operation on a compact liquid metal-cooled fast reactor (LMR) firstly by assessing the operation of a long-life fast reactor core and secondly by evaluating material performance in respect to both long-cycle operation and compact-size fast reactor. Many kinds of reactor concepts have been proposed, and LMR and small modular reactor (SMR) are the issued leading technologies for generation four (Gen-IV) reactor system development. The breed-and-burn strategy was proposed as a core burning strategy to operate a long cycle, and it has been evaluated in this paper with two reactor concepts: constant axial shape of neutron flux, nuclide densities, and power shape during life of energy and ultralong cycle fast reactor. In addition, Super-Safe, Small, and Simple and small modular fast reactor, compact LMR concepts, have been simulated to evaluate their long-life operation strategies. For the other practical issues, the materials for fuel, coolant, and structure have been identified and some of them are selected to have their performance optimized specifically for compact LMR with a long-cycle operation. It is believed that this comprehensive review will propose a proper direction for future reactor development and will be followed by the next step research for a complete reactor model with the other reactor components.

  14. CLOSED-CYCLE COOLING SYSTEMS FOR STEAM-ELECTRIC POWER PLANTS: A STATE-OF-THE-ART MANUAL

    EPA Science Inventory

    The report, in a practical manual format, gives results of a technical review of the state-of-the-art of thermal pollution control and treatment of cooling water in the steam-electric power generation industry. It assesses current, near horizon, and future technologies utilized o...

  15. Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists.

    PubMed

    Karlsen, A; Racinais, S; Jensen, M V; Nørgaard, S J; Bonne, T; Nybo, L

    2015-06-01

    This study investigated if well-trained cyclists improve V ˙ O 2 m a x and performance in cool conditions following heat acclimatization through natural outdoor training in hot conditions. Eighteen trained male cyclists were tested for physiological adaptations, V ˙ O 2 m a x , peak aerobic power output, exercise efficiency, and outdoor time trial (TT) performance (43.4 km in cool environment, ∼5-13 °C) before and after 2 weeks of training in a cool (CON, n = 9) or hot (∼35 °C, HA, n = 9) environment. After heat acclimatization, TT performance in the heat was improved by 16%; however, there was no change in the HA group in V ˙ O 2 m a x (4.79 ± 0.21 L/min vs 4.82 ± 0.35 L/min), peak aerobic power output (417 ± 16 W vs 422 ± 17 W), and outdoor TT performance in cool conditions (300 ± 14 W/69 ± 3 min vs 302 ± 9 W/69 ± 4 min). The present study shows that 2 weeks of heat acclimatization was associated with marked improvements in TT performance in the heat. However, for the well-trained endurance athletes, this did not transfer to an improved aerobic exercise capacity or outdoor TT performance in cool conditions. PMID:25943678

  16. High-resolution absorption spectrum of jet-cooled CH3Cl between 70 000 and 85 000 cm-1: New assignments

    NASA Astrophysics Data System (ADS)

    Cossart-Magos, Claudina; Jungen, Martin; Stalder, Joerg; Launay, Françoise

    2005-09-01

    The absorption spectrum of jet-cooled CH3Cl was photographed from 165to117nm (or 60000-85000cm-1, 7.5-10.5eV) at a resolution limit of 0.0008nm (0.3-0.6cm-1 or 0.04-0.08meV). Even in the best structured region of the spectrum, from 70000to85000cm-1 (8.7-10.5eV ), observed bandwidths (full width at half maximum) are large, from 50to150cm-1. No rotational feature could be resolved. The spectrum is dominated by two strong bands near 9eV, 140nm, the D and E bands of Mulliken [J. Chem. Phys. 8, 382 (1940)] or the spectral region D of Price [J. Chem. Phys.4, 539 (1936)]. Their relative intensity is incompatible with previous assignments, namely, to a triplet and a singlet state belonging to the same configuration. On the basis of the present ab initio calculations, those bands are now assigned to two singlet states, the A11 and E1 excited states resulting from the 2e34pe Rydberg configuration. The present calculations also reveal that the two E1 states issued from 2e34sa1 and 2e34pa1 are quasidegenerate and strongly mixed. They should be assigned to the two broad bands near 8eV, 160nm, the B and C bands of Mulliken and Price. Three vibrational modes are observed to be active: the CCl bond stretch ν3(a1), and the CH3 umbrella and rocking vibrations, respectively, ν2(a1) and ν6(e ). The fundamental frequencies deduced are well within the ranges defined by the corresponding values in the neutral and ion ground states. The possibility of a dynamical Jahn-Teller effect induced by the ν6(e) vibrational mode in the E1 Rydberg states is discussed.

  17. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    NASA Astrophysics Data System (ADS)

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Aziz, Ferhat; Permana, Sidik; Sekimoto, Hiroshi

    2014-02-01

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.

  18. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    SciTech Connect

    Monado, Fiber; Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Permana, Sidik; Aziz, Ferhat; Sekimoto, Hiroshi

    2014-02-12

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.

  19. Measurement of the cooling capacity of an RMC-Cryosystems Model LTS 4.5-025 closed-cycle helium refrigerator

    NASA Technical Reports Server (NTRS)

    De Zafra, R. L.; Mallison, W. H.; Emmons, L. K.; Koller, D.

    1991-01-01

    The cooling capacity of a recently purchased RMC-Cryosystems Model LTS 4.5-025 closed-cycle He refrigerator was measured over the range 4-35 K. It is found that the nominal cooling capacity of 250 mW is only met or exceeded over a narrow temperature range around 4.3 + or - 0.5 K, and that, above this range, there exists a considerable region of much lower cooling capacity, not exceeding about 100 mW. It is believed that this behavior results from use of a fixed-aperture Joule-Thompson expansion valve, and might be alleviated if the J-T valve could be adjusted to compensate for changing flow within the 5-20 K temperature range. Present performance may severely limit or prevent effective use in applications where an irreducible heat inflow exists which is greater than about 100 mW, yet substantially less than the quoted capacity at about 4 K.

  20. The second-law analysis of a recirculation cycle desiccant cooling system: Cosorption of water vapor and carbon dioxide

    NASA Astrophysics Data System (ADS)

    Shen, C. M.; Worek, W. M.

    The second law, of thermodynamics is applied to a desiccant cooling system operating in the recirculation mode. In this study, the adsorbent is 13X molecular sieve, and the process air stream is assumed to contain only dry air, water vapor, and carbon dioxide. The second law efficiencies of a desiccant wheel are documented in terms of overall number of transfer units and the regeneration temperature. The results show that based on the first law and second law of thermodynamics, a solid desiccant adsorber using 13X molecular sieve can be optimally designed.

  1. Thermal design and verification of an instrument cooling system for infrared detectors utilizing the Oxford Stirling cycle refrigerator

    NASA Technical Reports Server (NTRS)

    Werrett, Stephen; Seivold, Alfred L.

    1990-01-01

    A detailed nodal computer model was developed to thermally represent the hardware, and sensitivity studies were performed to evaluate design parameters and orbital environmental effects of an instrument cooling system for IR detectors. Thermal-vacuum testing showed excellent performance of the system and a correspondence with math model predictions to within 3 K. Results show cold stage temperature sensitivity to cold patch backload, outer stage external surface emittance degradation, and cold stage emittance degradation, respectively. The increase in backload on the cold patch over the mission lifetime is anticipated to be less than 3.0 watts, which translates to less than a 3-degree increase in detector temperatures.

  2. Simulating a 4-effect absorption chiller

    SciTech Connect

    Grossman, G.; Zaltash, A.; Adcock, P.W.; DeVault, R.C.

    1995-06-01

    Absorption chillers are heat-operated refrigeration machines that operate on one of the earliest known principles of refrigeration. Current absorption chillers typically use either steam or a gas-fired burner as the energy source. All current gas-fired absorption cooling systems are based on the well known single-effect or double-effect cycles. To further improve utilization of the high temperature heat available from natural gas, a variety of triple-effect cycles have been proposed and are being developed that are capable of substantial performance improvement over equivalent double-effect cycles. This article describes a study that investigated the possibility of even further improving utilization of the high temperature heat available from natural gas combustion. During the study, performance simulation was conducted for a 4-effect lithium bromide/water cycle. From an environmental perspective, absorption chillers provide several benefits. They use absorption pairs (such as lithium bromide/water) as the working fluids, rather than chlorofluorocarbons or hydrochlorofluorocarbons, which contribute to ozone depletion and global warming.

  3. Performance Analysis of Solution Transportation Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Kiani, Behdad; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Thermally activated advanced absorption cycles are considered promising candidates to replace CFCs, HCFCs and HFCs for residential and commercial applications. In such absorption systems, it is desirable to utilize the waste heat from industries for heating and cooling applications in commercial and residential sectors. For this purpose, it is necessary to transport energy over some distance because the waste heat source and demand are generally located apart from each other. Transportation of steam, hot water or chilled water requires high construction costs for insulation. There is an efficient method of energy transportation using absorption system called “ Solution Transportation Absorption System (STA)”. The solution is transported at an ambient temperature so that tube-insulations not required. This paper shows the simulation of the abovementioned system and the optimal result, using mathematical optimization. The optimum system with industry‧s waste heat utilization is obtained. At the end, the effect on the pollution emission and energy conservation is obtained.

  4. The feasibility study of small long-life gas cooled fast reactor with mixed natural Uranium/Thorium as fuel cycle input

    SciTech Connect

    Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Khairurrijal,; Monado, Fiber; Sekimoto, Hiroshi

    2012-06-06

    A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE burn-up scheme has been performed. In this study, design GCFR with Helium coolant which can be continuously operated by supplying mixed Natural Uranium/Thorium without fuel enrichment plant or fuel reprocessing plant. The active reactor cores are divided into two region, Thorium fuel region and Uranium fuel region. Each fuel core regions are subdivided into ten parts (region-1 until region-10) with the same volume in the axial direction. The fresh Natural Uranium and Thorium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh natural Uranium/Thorium fuel. This concept is basically applied to all regions in both cores area, i.e. shifted the core of i{sup th} region into i+1 region after the end of 10 years burn-up cycle. For the next cycles, we will add only Natural Uranium and Thorium on each region-1. The calculation results show the reactivity reached by mixed Natural Uranium/Thorium with volume ratio is 4.7:1. This reactor can results power thermal 550 MWth. After reactor start-up the operation, furthermore reactor only needs Natural Uranium/Thorium supply for continue operation along 100 years.

  5. The feasibility study of small long-life gas cooled fast reactor with mixed natural Uranium/Thorium as fuel cycle input

    NASA Astrophysics Data System (ADS)

    Ariani, Menik; Su'ud, Zaki; Waris, Abdul; Khairurrijal, Monado, Fiber; Sekimoto, Hiroshi

    2012-06-01

    A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE burn-up scheme has been performed. In this study, design GCFR with Helium coolant which can be continuously operated by supplying mixed Natural Uranium/Thorium without fuel enrichment plant or fuel reprocessing plant. The active reactor cores are divided into two region, Thorium fuel region and Uranium fuel region. Each fuel core regions are subdivided into ten parts (region-1 until region-10) with the same volume in the axial direction. The fresh Natural Uranium and Thorium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh natural Uranium/Thorium fuel. This concept is basically applied to all regions in both cores area, i.e. shifted the core of ith region into i+1 region after the end of 10 years burn-up cycle. For the next cycles, we will add only Natural Uranium and Thorium on each region-1. The calculation results show the reactivity reached by mixed Natural Uranium/Thorium with volume ratio is 4.7:1. This reactor can results power thermal 550 MWth. After reactor start-up the operation, furthermore reactor only needs Natural Uranium/Thorium supply for continue operation along 100 years.

  6. Effects of Lithospheric and Crustal Cooling and Global Sea-level Changes due to Glaciation Cycles on Paleogeography of the Galapagos

    NASA Astrophysics Data System (ADS)

    Zhong, S.; Geist, D.

    2012-12-01

    The paleogeography of the Galapagos archipelago is important in evolutionary and biogeographic studies. The Galapagos islands are located on young (< 12 Ma) seafloor near the spreading center between the Cocos and Nazca plates, and they are products of volcanism associated with melting of a mantle upwelling plume underlying the eastward moving Nazca plate. Most of the major islands lie on the Galapagos Platform, a broad plateau that rises 2 km above the surrounding seafloor. Many of the islands are separated by shallow seas only 100's meters deep, thus an accurate model of island elevation with time is necessary for assessing the paleogeography. A number of processes affect the paleogeography of oceanic islands, including erosion, thermal subsidence due to cooling of lithosphere, subsidence due to lithospheric loading, isostacy, and global sea-level changes. We examine the effects of thermal subsidence and global sea-level changes on the paleogeography of the Galapagos. We use the present day bathymetry and topography data from GEBCO as a starting point and reconstruct the bathymetry and topography for the Galapagos back in time by considering the effects of thermal subsidence and global sea-level changes. Thermal subsidence due to lithospheric cooling is relatively straightforward, provided that lithospheric age is known. However, this process is complicated by the continual construction of the platform over the course of > 2 million years, which slows down the lithospheric cooling and resets the cooling age. Therefore, the net thermal subsidence is controlled by the cooling of the both lithosphere and the newly added volcanic rocks (i.e., locally on the islands and the regional platform). Global sea-level changes due to glaciation cycles occur on a relatively short time scales (~10 ka) and can cause more than 100 meter sea level drops in the Galapagos at the last glacial maximum 25 ka ago, according to recent global sea-level change models that consider ice

  7. Stability of IRA-45 solid amine resin as a function of carbon dioxide absorption and steam desorption cycling

    NASA Technical Reports Server (NTRS)

    Wood, Peter C.; Wydeven, Theodore

    1987-01-01

    The removal of CO2 from the NASA Space Station's cabin atmosphere, which may be undertaken by a solid-amine water (steam)-desorbed system, is presently evaluated with a view to long-term amine resin stability and adsorption/desorption cycling by means of an automated laboratory flow-testing facility. While the CO2-adsorption capacity of the IRA-45 amine resin used gradually decreased over time, the rate of degradation significantly decreased after the first 10 cycles. Attention is given to the presence (and possible need for removal) of trimethylamine in the process air downstream of the resin bed.

  8. Energy-conserving passive solar multi-family retrofit projects. Cycle 5, category 1: HUD Solar Heating and Cooling Demonstration Program

    NASA Astrophysics Data System (ADS)

    1981-10-01

    A total of 14 passive solar retrofit buildings are described. The concept of passive solar energy and the various types of passive systems found in the Cycle 5 projects are discussed. Each of the 14 solar designs is described, and some of the key points raised in the discussion of passive concepts are illustrated. Each project description cites the location of the passive solar home and presents the following information: grantee/builder, designer, solar designer, price, number of units, net heated area, heat load, degree days, solar fraction of the total heat load, and auxiliary heat required. Project descriptions also include data on recognition factors (the five passive elements necessary for a complete passive system), the type of auxiliary heating system used in the building, the solar water heating system (if any), and the passive cooling techniques used (if any).

  9. Phase Transfer-Catalyzed Fast CO2 Absorption by MgO-Based Absorbents with High Cycling Capacity

    SciTech Connect

    Zhang, Keling; Li, Xiaohong S.; Li, Weizhen; Rohatgi, Aashish; Duan, Yuhua; Singh, Prabhakar; Li, Liyu; King, David L.

    2014-06-01

    CO2 capture from pre-combustion syngas in the temperature range of 250-400°C is highly desirable from an energy efficiency perspective. Thermodynamically, MgO is a promising material for CO2 capture, but the gas-solid reaction to produce MgCO3 is kinetically slow due to high lattice energy. We report here fast CO2 absorption over a solid MgO-molten nitrate/nitrite aggregate through phase transfer catalysis, in which the molten phase serves as both a catalyst and reaction medium. Reaction with CO2 at the gas-solid-liquid triple phase boundary results in formation of MgCO3 with significant reaction rate and a high conversion of MgO. This methodology is also applicable to other alkaline earth oxides, inspiring the design of absorbents which require activation of the bulk material.

  10. The study of capability natural uranium as fuel cycle input for long life gas cooled fast reactors with helium as coolant

    NASA Astrophysics Data System (ADS)

    Ariani, Menik; Satya, Octavianus Cakra; Monado, Fiber; Su'ud, Zaki; Sekimoto, Hiroshi

    2016-03-01

    The objective of the present research is to assess the feasibility design of small long-life Gas Cooled Fast Reactor with helium as coolant. GCFR included in the Generation-IV reactor systems are being developed to provide sustainable energy resources that meet future energy demand in a reliable, safe, and proliferation-resistant manner. This reactor can be operated without enrichment and reprocessing forever, once it starts. To obtain the capability of consuming natural uranium as fuel cycle input modified CANDLE burn-up scheme was adopted in this system with different core design. This study has compared the core with three designs of core reactors with the same thermal power 600 MWth. The fuel composition each design was arranged by divided core into several parts of equal volume axially i.e. 6, 8 and 10 parts related to material burn-up history. The fresh natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of the region (i) into region (i+1) region after the end of 10 years burn-up cycle. The calculation results shows that for the burn-up strategy on "Region-8" and "Region-10" core designs, after the reactors start-up the operation furthermore they only needs natural uranium supply to the next life operation until one period of refueling (10 years).

  11. Neon helium mixtures as a refrigerant for the FCC beam screen cooling: comparison of cycle design options

    NASA Astrophysics Data System (ADS)

    Kloeppel, S.; Quack, H.; Haberstroh, C.; Holdener, F.

    2015-12-01

    In the course of the studies for the next generation particle accelerators, in this case the Future Circular Collider for hadron-hadron interaction (FCC-hh), different aspects are being investigated. One of these is the heat load on the beam screen, which results mainly from the synchrotron radiation. In case of the FCC-hh, a heat load of 6 MW is expected. The heat has to be absorbed at 40 to 60 K due to vacuum restrictions. In this range, refrigeration is possible with both helium and neon. Our investigations are focused on a mixed refrigerant of these two components, which combines the advantages of both. Especially promising is the possible substitution of the oil flooded screw compressors by more efficient turbo compressors. This paper investigates different flow schemes and mixture compositions with respect to complexity and efficiency. Furthermore, thermodynamic aspects, e.g. whether to use cold or warm secondary cycle compressors are discussed. Additionally, parameters of the main compressor are established.

  12. State-of-the-Art Review on Crystallization Control Technologies for water/LiBr Absorption Heat Pumps

    SciTech Connect

    Wang, Kai; Abdelaziz, Omar; Kisari, Padmaja; Vineyard, Edward Allan

    2011-01-01

    The key technical barrier to using water/lithium bromide (LiBr) as the working fluid in aircooled absorption chillers and absorption heat-pump systems is the risk of crystallization when the absorber temperature rises at fixed evaporating pressure. This article reviews various crystallization control technologies available to resolve this problem: chemical inhibitors, heat and mass transfer enhancement methods, thermodynamic cycle modifications, and absorption system-control strategies. Other approaches, such as boosting absorber pressure and J-tube technology, are reviewed as well. This review can help guide future efforts to develop water/LiBr air-cooled absorption chillers and absorption heatpump systems.

  13. Development of Exhaust Gas Driven Absorption Chiller-Heater

    NASA Astrophysics Data System (ADS)

    Inoue, Naoyuki; Endou, Tetsuya; Saito, Kiyoshi; Kawai, Sunao

    Micro gas turbines are expected as engines for the distributed co-generation systems, performing power generation and heat recovery. Waste heat from micro gas turbines are discharged in the form of exhaust gas, and it is simple that exhaust gas is directly supplied to an absorption refrigerator. In this paper, we evaluated various single-double effect absorption cycles for exhaust gas driven absorption refrigerators, and clarified that the difference of performance among these cycles are little. We adopted one of these cycles for the prototype machine, and experimented with it to get the partial load characteristics and the effect of cooling water temperature on the performance. Based on the experimental data, we developed as imulation model of the static characteristics, and studied the direction of improvement.

  14. Sodium supplementation has no effect on endurance performance during a cycling time-trial in cool conditions: a randomised cross-over trial

    PubMed Central

    2013-01-01

    Background Sodium ingestion during exercise may exert beneficial effects on endurance performance by either its ability to attenuate the decrease in plasma volume or reduce the risk of Exercise Associated Hyponatremia (EAH). This study aimed to investigate the effect of sodium supplements on endurance performance during a 72 km road cycling time-trial in cool conditions (13.8 ± 2.0°C). Methods Nine well-trained cyclists (5 male, 4 female) participated in this randomized, double-blinded cross-over study, receiving either a 700 mg.h-1 salt capsule, or a corn flour placebo during the time trial. Water was ingested ad-libitum throughout the time trial. Measurements were taken pre, post, and 40 min following time-trials, analysing blood, sweat, and urinary hydration and sodium concentration. Results Sodium supplements had no effect on time-trial performance (overall time = 171 min sodium vs. 172 min placebo; p = 0.46). There was also no effect on the change in plasma sodium concentration from pre to post time trial between trials (relative plasma [Na+] change (pre-post): sodium = 0.56%, placebo = 0.47%; p = 0.60). The greatest difference observed was a significantly change in plasma volume from pre to post exercise between the salt and the placebo trial (p = 0.02), which corresponded with an increased thirst with sodium supplementation. Conclusion Sodium supplements therefore do not improving performance during exercise of approximately 3 h duration in cool conditions. PMID:23731903

  15. Formation of an SEI on a LiMn(2)O(4) Cathode during Room Temperature Charge-Discharge Cycling Studied by Soft X-Ray Absorption Spectroscopy at the Fluorine K-edge

    SciTech Connect

    Chung, K.Y.; Yang, X.; Yoon, W.-S.; Kim, K.-B.; Cho, B.-W.

    2011-11-01

    The solid electrolyte interface (SEI) formation on the surface of LiMn{sub 2}O{sub 4} electrodes during room temperature charge-discharge cycling was studied using soft X-ray absorption spectroscopy at the Fluorine (F) K-edge. LiMn{sub 2}O{sub 4} electrodes without any binder were prepared by electrostatic spray deposition to eliminate the signal originating from the PVDF binder in the F K-edge X-ray absorption spectra. The F K-edge absorption spectra show that the SEI layer forms at a very early stage of cycling. SEI growth takes place during discharge. In addition, LiF formation is accelerated if the discharge step follows a charge step. The F K-edge absorption spectra suggest that the major component of the SEI is LiF.

  16. Purge needs in absorption chillers

    SciTech Connect

    Murray, J.G. )

    1993-10-01

    Absorption chillers are regaining a significant share of large tonnage chiller sales, such as they had 20 years ago. Gas-fired chillers are now available that have a base energy (ultimate fuel usage) consumption rate per ton comparable to that in electric units. Effective purging in an absorption chiller is an absolute necessity to achieve the low chilled water temperature needed for dehumidification and to fully benefit from the energy savings offered by double-effect cycles. Although the purge system is usually not shown on the typical cycle schematic, its proper functioning is a key requirement for satisfactory machine operation. This article discusses the effect of noncondensible (N/C) gases on the absorption cooling process and the basics of purge systems. In addition, the article discusses the rationale for the important design step of selecting the location of the N/C probe, and discusses purge systems applicable to the direct-fired, double-effect machines now entering the marketplace.

  17. Degradation of thermal barrier coatings on an Integrated Gasification Combined Cycle (IGCC) simulated film-cooled turbine vane pressure surface due to particulate fly ash deposition

    NASA Astrophysics Data System (ADS)

    Luo, Kevin

    Coal synthesis gas (syngas) can introduce contaminants into the flow of an Integrated Gasification Combined Cycle (IGCC) industrial gas turbine which can form molten deposits onto components of the first stage of a turbine. Research is being conducted at West Virginia University (WVU) to study the effects of particulate deposition on thermal barrier coatings (TBC) employed on the airfoils of an IGCC turbine hot section. WVU had been working with U.S. Department of Energy, National Energy Technology Laboratory (NETL) to simulate deposition on the pressure side of an IGCC turbine first stage vane to study the effects on film cooling. To simulate the particulate deposition, TBC coated, angled film-cooled test articles were subjected to accelerated deposition injected into the flow of a combustor facility with a pressure of approximately 4 atm and a gas temperature of 1560 K. The particle characteristics between engine conditions and laboratory are matched using the Stokes number and particulate loading. To investigate the degradation on the TBC from the particulate deposition, non-destructive evaluations were performed using a load-based multiple-partial unloading micro-indentation technique and were followed by scanning electron microscopy (SEM) evaluation and energy dispersive X-ray spectroscopy (EDS) examinations. The micro-indentation technique used in the study was developed by Kang et al. and can quantitatively evaluate the mechanical properties of materials. The indentation results found that the Young's Modulus of the ceramic top coat is higher in areas with deposition formation due to the penetration of the fly ash. The increase in the modulus of elasticity has been shown to result in a reduction of strain tolerance of the 7% yttria-stabilized zirconia (7YSZ) TBC coatings. The increase in the Young's modulus of the ceramic top coat is due to the stiffening of the YSZ columnar microstructure from the cooled particulate fly ash. SEM evaluation was used to

  18. Development of a plant dynamics computer code for analysis of a supercritical carbon dioxide Brayton cycle energy converter coupled to a natural circulation lead-cooled fast reactor.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.

    2007-03-08

    STAR-LM is a lead-cooled pool-type fast reactor concept operating under natural circulation of the coolant. The reactor core power is 400 MWt. The open-lattice core consists of fuel pins attached to the core support plate, (the does not consist of removable fuel assemblies). The coolant flows outside of the fuel pins. The fuel is transuranic nitride, fabricated from reprocessed LWR spent fuel. The cladding material is HT-9 stainless steel; the steady-state peak cladding temperature is 650 C. The coolant is single-phase liquid lead under atmospheric pressure; the core inlet and outlet temperatures are 438 C and 578 C, respectively. (The Pb coolant freezing and boiling temperatures are 327 C and 1749 C, respectively). The coolant is contained inside of a reactor vessel. The vessel material is Type 316 stainless steel. The reactor is autonomous meaning that the reactor power is self-regulated based on inherent reactivity feedbacks and no external power control (through control rods) is utilized. The shutdown (scram) control rods are used for startup and shutdown and to stop the fission reaction in case of an emergency. The heat from the reactor is transferred to the S-CO{sub 2} Brayton cycle in in-reactor heat exchangers (IRHX) located inside the reactor vessel. The IRHXs are shell-and-tube type heat exchangers with lead flowing downwards on the shell side and CO{sub 2} flowing upwards on the tube side. No intermediate circuit is utilized. The guard vessel surrounds the reactor vessel to contain the coolant, in the very unlikely event of reactor vessel failure. The Reactor Vessel Auxiliary Cooling System (RVACS) implementing the natural circulation of air flowing upwards over the guard vessel is used to cool the reactor, in the case of loss of normal heat removal through the IRHXs. The RVACS is always in operation. The gap between the vessels is filled with liquid lead-bismuth eutectic (LBE) to enhance the heat removal by air by significantly reducing the thermal

  19. Absorption and adsorption chillers applied to air conditioning systems

    NASA Astrophysics Data System (ADS)

    Kuczyńska, Agnieszka; Szaflik, Władysław

    2010-07-01

    This work presents an application possibility of sorption refrigerators driven by low temperature fluid for air conditioning of buildings. Thermodynamic models were formulated and absorption LiBr-water chiller with 10 kW cooling power as well as adsorption chiller with silica gel bed were investigated. Both of them are using water for desorption process with temperature Tdes = 80 °C. Coefficient of performance (COP) for both cooling cycles was analyzed in the same conditions of the driving heat source, cooling water Tc = 25 °C and temperature in evaporator Tevap = 5 °C. In this study, the computer software EES was used to investigate the performance of absorption heat pump system and its behaviour in configuration with geothermal heat source.

  20. Parametric study of a silica gel-water adsorption refrigeration cycle -- The influence of thermal capacitance and heat exchanger UA-values on cooling capacity, power density, and COP

    SciTech Connect

    Boelman, E.C.; Saha, B.B.; Kashiwagi, Takao

    1997-12-31

    The influence of heat exchanger UA-values (adsorber/desorber, evaporator, and condenser) is investigated for an adsorption chiller, with consideration given to the thermal capacitance of the adsorber/desorber by means of a lumped-parameter cycle simulation model developed by the authors and co-workers for the single-stage silica gel-water adsorption chiller. The closed-cycle-type chiller, for use in air conditioning, is driven by low-grade waste heat (85 C [185 F]) and cooled by water at 31 C (88 F) and operates on relatively short cycle times (420 seconds adsorption/desorption; 30 second adsorber/desorber sensible cooling and heating). The results showed cycle performance to be considerably affected by the thermal capacitance and UA-value of the adsorber/desorber, which is attributed to the severe sensible cooling/heating requirements resulting from batched cycle operation. The model is also sensitive to the evaporator UA-value--but to a lesser extent. The condenser UA-value is the least sensitive parameter due to the working pair adsorption behavior in the temperature range defined for desorption and condensation.

  1. High-resolution absorption cross section measurements of supersonic jet-cooled carbon monoxide between 92.5 and 97.4 nanometers

    NASA Technical Reports Server (NTRS)

    Yoshino, K.; Stark, G.; Esmond, J. R.; Smith, P. L.; Ito, K.; Matsui, T.

    1995-01-01

    High-resolution photoabsorption cross sections for eight CO bands, at wavelengths between 92.5 nm and 97.4 nm, have been measured in a supersonic jet-cooled source (approximately equals 20 K) at the Photon Factory synchrotron radiation facility. New integrated cross sections are reported for four bands between 92.5 nm and 94.2 nm. A low-temperature spectrum of the W(1)-X(0) band (95.6 nm), which was used to determine the absorbing CO column densities, is also presented. Additional jet-cooled cross section measurements were made on the L(0)-X(0), K(0)-X(0), and W(0)-X(0) bands (96.7-97.4 nm) which verify previously published results. A self-consistent set of band oscillator strengths is presented for the eight bands studied.

  2. Investigation of plant control strategies for the supercritical C0{sub 2}Brayton cycle for a sodium-cooled fast reactor using the plant dynamics code.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J.

    2011-04-12

    The development of a control strategy for the supercritical CO{sub 2} (S-CO{sub 2}) Brayton cycle has been extended to the investigation of alternate control strategies for a Sodium-Cooled Fast Reactor (SFR) nuclear power plant incorporating a S-CO{sub 2} Brayton cycle power converter. The SFR assumed is the 400 MWe (1000 MWt) ABR-1000 preconceptual design incorporating metallic fuel. Three alternative idealized schemes for controlling the reactor side of the plant in combination with the existing automatic control strategy for the S-CO{sub 2} Brayton cycle are explored using the ANL Plant Dynamics Code together with the SAS4A/SASSYS-1 Liquid Metal Reactor (LMR) Analysis Code System coupled together using the iterative coupling formulation previously developed and implemented into the Plant Dynamics Code. The first option assumes that the reactor side can be ideally controlled through movement of control rods and changing the speeds of both the primary and intermediate coolant system sodium pumps such that the intermediate sodium flow rate and inlet temperature to the sodium-to-CO{sub 2} heat exchanger (RHX) remain unvarying while the intermediate sodium outlet temperature changes as the load demand from the electric grid changes and the S-CO{sub 2} cycle conditions adjust according to the S-CO{sub 2} cycle control strategy. For this option, the reactor plant follows an assumed change in load demand from 100 to 0 % nominal at 5 % reduction per minute in a suitable fashion. The second option allows the reactor core power and primary and intermediate coolant system sodium pump flow rates to change autonomously in response to the strong reactivity feedbacks of the metallic fueled core and assumed constant pump torques representing unchanging output from the pump electric motors. The plant behavior to the assumed load demand reduction is surprising close to that calculated for the first option. The only negative result observed is a slight increase in the intermediate

  3. Nebular UV Absorption Lines in Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Dinerstein, Harriet

    We propose to continue our Cycle 1 program of studying the Lyman and Werner bands of H_2, seen in absorption against the UV continua of planetary nebula central stars, which arise within neutral-molecular envelopes surrounding the ionized gas. These are the pump lines for a fluorescent cascade of near-infrared emission lines which are observed in many planetary nebulae. By observing the UV lines we can probe the chemical and thermal structure of the envelopes, as well as measure molecular column densities and clarify the excitation processes for the infrared lines. In Cycle 1 we were granted time for three targets, one of which was successfully observed shortly before submission of this proposal. Although the data were not yet available for examination, similar target observed by the project team revealed a rich set of H_2 circumstellar absorption features, demonstrating the feasibility of our program. FUSE spectra also include absorption features from atomic species such as O I and C II, which give rise to important far-infrared fine-structure cooling lines that likewise have been observed from planetary nebulae. In Cycle 2, we add as a secondary goal a search for nebular components of the O VI 032, 1038 AA absorption lines, which trace the presence of hot shocked gas, in nebulae with anomalously strong optical recombination lines of ions of oxygen and nitrogen. This will test a plausible hypothesis for the origin of this anomaly.

  4. Power electronics cooling apparatus

    DOEpatents

    Sanger, Philip Albert; Lindberg, Frank A.; Garcen, Walter

    2000-01-01

    A semiconductor cooling arrangement wherein a semiconductor is affixed to a thermally and electrically conducting carrier such as by brazing. The coefficient of thermal expansion of the semiconductor and carrier are closely matched to one another so that during operation they will not be overstressed mechanically due to thermal cycling. Electrical connection is made to the semiconductor and carrier, and a porous metal heat exchanger is thermally connected to the carrier. The heat exchanger is positioned within an electrically insulating cooling assembly having cooling oil flowing therethrough. The arrangement is particularly well adapted for the cooling of high power switching elements in a power bridge.

  5. The development of a solar-powered residential heating and cooling system

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Efforts to demonstrate the engineering feasibility of utilizing solar power for residential heating and cooling are described. These efforts were concentrated on the analysis, design, and test of a full-scale demonstration system which is currently under construction at the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville, Alabama. The basic solar heating and cooling system under development utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating and water heating, and an absorption cycle air conditioner for space cooling.

  6. High-efficiency gas heat pump air-conditioner equipped with absorption refrigerator

    NASA Astrophysics Data System (ADS)

    Imai, Yosuke; Ohashi, Toshinori; Okamoto, Hiroaki; Hihara, Eiji; Kawakami, Ryuichiro

    On conventional gas heat pump(GHP), waste heat from gas engine that uses as driving source is emitted into outside. So from the standpoint of efficient use of waste heat, it is assumed that waste heat from gas engine is used as driving source of absorption chiller, and high temperature condensate refrigerant in GHP is subcooled to middle temperature by cold source from absorption cycle, and as a result, GHP makes more efficiency. However, in equipping GHP with absorption cycle, downsizing and high-efficiency of absorption cycle is required. In this study, air-cooled subcooled adiabatic absorber is focused and physical phenomenon in it is analyzed, and finally one perception of the optimized designing is shown.

  7. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  8. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  9. Experimental investigation of an advanced adsorption refrigeration cycle

    SciTech Connect

    Saha, B.B.; Kashiwagi, Takao

    1997-12-31

    Experimental measurements are made for a silica gel-water advanced absorption refrigeration chiller (1.2-kW [4,095-Btu/h] cooling capacity) to evaluate its performance under different temperature and adsorption/desorption cycle time conditions. This paper describes the operating principle of the chiller, outlines the experimental hardware, and discusses results obtained by varying the cooling and hot water inlet temperatures and adsorption/desorption cycle times, as well as their agreement with the simulated results given by a lumped parameter model. The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). Excellent qualitative agreement was obtained between the experimental data and simulated results. The results showed the advanced three-stage cycle to be particularly well suited for operation with low-grade-temperature waste heat as the driving source, since it worked with small regenerating temperature lifts (heat source-heat sink temperature) of 10 to 30 K.

  10. Thermal model of solar absorption HVAC systems

    SciTech Connect

    Bergquam, J.B.; Brezner, J.M. |

    1995-11-01

    This paper presents a thermal model that describes the performance of solar absorption HVAC systems. The model considers the collector array, the building cooling and heating loads, the absorption chiller and the high temperature storage. Heat losses from the storage tank and piping are included in the model. All of the results presented in the paper are for an array of flat plate solar collectors with black chrome (selective surface) absorber plates. The collector efficiency equation is used to calculate the useful heat output from the array. The storage is modeled as a non-stratified tank with polyurethane foam insulation. The system is assumed to operate continuously providing air conditioning during the cooling season, space heating during the winter and hot water throughout the year. The amount of heat required to drive the chiller is determined from the coefficient of performance of the absorption cycle. Results are presented for a typical COP of 0.7. The cooling capacity of the chiller is a function of storage (generator) temperature. The nominal value is 190 F (88 C) and the range of values considered is 180 F (82 C) to 210 F (99 C). Typical building cooling and heating loads are determined as a function of ambient conditions. Performance results are presented for Sacramento, CA and Washington, D.C. The model described in the paper makes use of National Solar Radiation Data Base (NSRDB) data and results are presented for these two locations. The uncertainties in the NSRDB are estimated to be in a range of 6% to 9%. This is a significant improvement over previously available data. The model makes it possible to predict the performance of solar HVAC systems and calculate quantities such as solar fraction, storage temperature, heat losses and parasitic power for every hour of the period for which data are available.

  11. Stochastic Cooling

    SciTech Connect

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  12. Semioptimal practicable algorithmic cooling

    SciTech Connect

    Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2011-04-15

    Algorithmic cooling (AC) of spins applies entropy manipulation algorithms in open spin systems in order to cool spins far beyond Shannon's entropy bound. Algorithmic cooling of nuclear spins was demonstrated experimentally and may contribute to nuclear magnetic resonance spectroscopy. Several cooling algorithms were suggested in recent years, including practicable algorithmic cooling (PAC) and exhaustive AC. Practicable algorithms have simple implementations, yet their level of cooling is far from optimal; exhaustive algorithms, on the other hand, cool much better, and some even reach (asymptotically) an optimal level of cooling, but they are not practicable. We introduce here semioptimal practicable AC (SOPAC), wherein a few cycles (typically two to six) are performed at each recursive level. Two classes of SOPAC algorithms are proposed and analyzed. Both attain cooling levels significantly better than PAC and are much more efficient than the exhaustive algorithms. These algorithms are shown to bridge the gap between PAC and exhaustive AC. In addition, we calculated the number of spins required by SOPAC in order to purify qubits for quantum computation. As few as 12 and 7 spins are required (in an ideal scenario) to yield a mildly pure spin (60% polarized) from initial polarizations of 1% and 10%, respectively. In the latter case, about five more spins are sufficient to produce a highly pure spin (99.99% polarized), which could be relevant for fault-tolerant quantum computing.

  13. Simulation of Bichromatic Force Cooling

    NASA Astrophysics Data System (ADS)

    Hua, Xiang; Corder, Christopher; Metcalf, Harold

    2016-05-01

    Laser cooling without spontaneous emission as implemented by the bichromatic force (BF) remains a controversial topic. We have done a numerical simulation of the BF on He using the 23 S <--> 33 P transition at λ = 389 nm in order to support the interpretation of previously reported measurements. Our experiments and the simulation reported here use a time scale comparable to the excited state lifetime so that spontaneous emission cannot contribute significantly. The average velocity change is 30 - 40 times larger than the recoil velocity but the measurements of both phase space and velocity space compression are limited by the longitudinal velocity spread of the atomic beam to ~ 2. The simulation clearly shows this spreading. The code passed several preliminary tests using single-frequency traveling and standing waves, and then it was run with the appropriate bichromatic light fields. Its output agrees very well with the measurements and, most importantly, shows that significant laser cooling is indeed possible on a time scale comparable to that of a single absorption-spontaneous cycle. Supported by ONR.

  14. Stability of CsH5(PO4)2-based composites at fixed temperatures and during heating-cooling cycles for solid-state intermediate temperature fuel cells

    NASA Astrophysics Data System (ADS)

    Qing, Geletu; Kikuchi, Ryuji; Takagaki, Atsushi; Sugawara, Takashi; Oyama, Shigeo Ted

    2016-02-01

    This work reports the stability of CsH5(PO4)2-based composites at fixed temperatures (158 °C and 210 °C) and during three heating-cooling cycles (106 °C → 158 °C → 106 °C). Composites of CsH5(PO4)2 and SiO2 prepared by pressing the corresponding powders were stable at fixed temperatures, but were not stable during repeated heating and cooling due to the structural damage or existence of CsH5(PO4)2 particles that were not highly dispersed in the silica matrix. Composites of CsH5(PO4)2 and SiP2O7 absorbed a large amount of water into the electrolyte inner phase and formed a paste. The absorbed water had a significant influence on the electrolyte conductivity. Doped glasses of CsH5(PO4)2, which had an interconnected silica matrix with 5-12 nm pores filled with CsH5(PO4)2, exhibited stable conductivity both at fixed temperatures and during three heating-cooling cycles. From these findings, it was concluded that matrices with both strong interfacial interaction with CsH5(PO4)2 and interconnected structure were important to the preparation of CsH5(PO4)2-based composites with high stability.

  15. Sorption Refrigeration / Heat Pump Cycles

    NASA Astrophysics Data System (ADS)

    Saha, Bidyut Baran; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Over the past few decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Up to now, only the desiccant evaporative cooling system of the open type has achieved commercial use, predominantly in the United States. Closed-type adsorption refrigeration and heat pump systems are rarely seen in the market, or are still in the laboratory testing stage. Promising recent development have been made in Japan for the use of porous metal hydrides and composite adsorbents. In this paper, a short description of adsorption theories along with an overview of present status and future development trends of thermally powered adsorption refrigeration cycles are outlined putting emphasis on experimental achievements. This paper also addressed some advanced absorption cycles having relatively higher COP, and also summarizes fundamental concepts of GAX cycles and various GAX cycles developed for heat pump applications.

  16. Cool Stars Sing the Blues

    NASA Astrophysics Data System (ADS)

    Luttermoser, D. G.

    2005-12-01

    A high-dispersion spectral atlas of cool red giant stars in the blue and violet is presented. The spectra were obtained over a six-year time period with the stellar spectrograph of the McMath-Pierce Telescope on Kitt Peak. Both N-type carbon stars and M-type oxygen-rich stars are presented from 3900 to 4600 Å, with the M-type stars containing both semiregular and Mira-type variables. The dominant absorption features in these stars at these wavelength result primarily from neutral metals, especially iron, and the CH and CN diatomic molecules. The Miras also show strong emission lines during some of their pulsation cycle. Many of these emission lines result from fluorescence from the Mg II h & k lines in the UV. For these fluoresced features, comparisons are made between the Miras and the semiregular carbon-rich and oxygen-rich variables. Where the oxygen-rich semiregulars show no hint of fluorescence in these features, the carbon stars show a definite ``filling-in'' of the absorption lines.

  17. Internal dissipation and heat leaks in quantum thermodynamic cycles.

    PubMed

    Correa, Luis A; Palao, José P; Alonso, Daniel

    2015-09-01

    The direction of the steady-state heat currents across a generic quantum system connected to multiple baths may be engineered to realize virtually any thermodynamic cycle. In spite of their versatility, such continuous energy-conversion systems are generally unable to operate at maximum efficiency due to non-negligible sources of irreversible entropy production. In this paper we introduce a minimal model of irreversible absorption chiller. We identify and characterize the different mechanisms responsible for its irreversibility, namely heat leaks and internal dissipation, and gauge their relative impact in the overall cooling performance. We also propose reservoir engineering techniques to minimize these detrimental effects. Finally, by looking into a known three-qubit embodiment of the absorption cooling cycle, we illustrate how our simple model may help to pinpoint the different sources of irreversibility naturally arising in more complex practical heat devices. PMID:26465455

  18. Internal dissipation and heat leaks in quantum thermodynamic cycles

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.; Palao, José P.; Alonso, Daniel

    2015-09-01

    The direction of the steady-state heat currents across a generic quantum system connected to multiple baths may be engineered to realize virtually any thermodynamic cycle. In spite of their versatility, such continuous energy-conversion systems are generally unable to operate at maximum efficiency due to non-negligible sources of irreversible entropy production. In this paper we introduce a minimal model of irreversible absorption chiller. We identify and characterize the different mechanisms responsible for its irreversibility, namely heat leaks and internal dissipation, and gauge their relative impact in the overall cooling performance. We also propose reservoir engineering techniques to minimize these detrimental effects. Finally, by looking into a known three-qubit embodiment of the absorption cooling cycle, we illustrate how our simple model may help to pinpoint the different sources of irreversibility naturally arising in more complex practical heat devices.

  19. Development of an Ionic-Liquid Absorption Heat Pump

    SciTech Connect

    Holcomb, Don

    2011-03-29

    Solar Fueled Products (SFP) is developing an innovative ionic-liquid absorption heat pump (ILAHP). The development of an ILAHP is extremely significant, as it could result in annual savings of more than 190 billion kW h of electrical energy and $19 billion. This absorption cooler uses about 75 percent less electricity than conventional cooling and heating units. The ILAHP also has significant environmental sustainability benefits, due to reduced CO2 emissions. Phase I established the feasibility and showed the economic viability of an ILAHP with these key accomplishments: • Used the breakthrough capabilities provided by ionic liquids which overcome the key difficulties of the common absorption coolers. • Showed that the theoretical thermodynamic performance of an ILAHP is similar to existing absorption-cooling systems. • Established that the half-effect absorption cycle reduces the peak generator temperature, improving collector efficiency and reducing collector area. • Component testing demonstrated that the most critical components, absorber and generator, operate well with conventional heat exchangers. • Showed the economic viability of an ILAHP. The significant energy savings, sustainability benefits, and economic viability are compelling reasons to continue the ILAHP development.

  20. Feasibility and operating costs of an air cycle for CCHP in a fast food restaurant

    DOE PAGESBeta

    Perez-Blanco, Horacio; Vineyard, Edward

    2016-05-06

    This work considers the possibilities of an air-based Brayton cycle to provide the power, heating and cooling needs of fast-food restaurants. A model of the cycle based on conventional turbomachinery loss coefficients is formulated. The heating, cooling and power capabilities of the cycle are extracted from simulation results. Power and thermal loads for restaurants in Knoxville, TN and in International Falls, MN, are considered. It is found that the cycle can meet the loads by setting speed and mass flow-rate apportionment between the power and cooling functional sections. The associated energy costs appear elevated when compared to the cost ofmore » operating individual components or a more conventional, absorption-based CHP system. Lastly, a first-order estimate of capital investments is provided. Suggestions for future work whereby the operational costs could be reduced are given in the conclusions.« less

  1. Study on the Partial Load Characteristics of Double-Effect Absorption Systems

    NASA Astrophysics Data System (ADS)

    Kawakami, Ryuichiro; Fukuchi, Toru; Kaita, Yoshio

    Simulation analysis was carried out to study the partial load characteristics of three different types of double-effect LiBr-water absorption cycle, namely series flow, parallel flow and reverse flow. A computer program was developed for this study to simulate the behavior of the absorption cycles equipped with flow rate control of absorbent, cooling water and chilling water on partial load. The effects of the flow rate control on the coefficient of performance (COP), the maximum temperature and maximum pressure were studied. The results show that not only flow rate control of absorbent is essential for high COP on the partial load, but also flow rate control of cooling water and chilling water is recommendable to save the power of pumping.

  2. Design and operation of a solar heating and cooling system for a residential size building

    NASA Technical Reports Server (NTRS)

    Littles, J. W.; Humphries, W. R.; Cody, J. C.

    1978-01-01

    The first year of operation of solar house is discussed. Selected design information, together with a brief system description is included. The house was equipped with an integrated solar heating and cooling system which uses fully automated state-of-the art. Evaluation of the data indicate that the solar house heating and cooling system is capable of supplying nearly 100 percent of the thermal energy required for heating and approximately 50 percent of the thermal energy required to operate the absorption cycle air conditioner.

  3. Preliminary studies on the heat exchanger option for S-CO{sub 2} power conversion cycle coupled to water cooled SMR

    SciTech Connect

    Ahn, Y.; Lee, J.; Lee, J. I.

    2012-07-01

    For more than a half century, the steam Rankine cycle had been the major power conversion cycle for a nuclear power plant. However, as the interest on the next generation reactors grows, a variety of alternative power conversion systems have been studied. Among them, the S-CO{sub 2} cycle (Supercritical carbon dioxide Brayton cycle) is considered as a promising candidate due to several benefits such as 1) Relatively high thermal efficiency at relatively low turbine inlet temperature, 2) High efficiency with simple lay-out 3) Compactness of turbo-machineries. 4) Compactness of total cycle combined with PCHE (Printed Circuit Heat Exchanger). According to the conventional classification of heat exchangers (HE), there are three kind of HE, 1) Tubular HEs, 2) Plate-type HEs, 3) Extended surface HEs. So far, the researcher has mostly assumed PCHE type HE for the S-CO{sub 2} cycle due to its compactness with reasonably low pressure drop. However, PCHE is currently one of the most expensive components in the cycle, which can have a negative effect on the economics of the cycle. Therefore, an alternative for the HE should be seriously investigated. By comparing the operating condition (pressure and temperature) there are three kind of HE in the S-CO{sub 2} cycle, 1) IHX (Intermediate Heat exchanger) 2) Recuperator and 3) Pre-cooler. In each heat exchanger, hot side and cold side coolants are different, i.e. reactor coolant to S-CO{sub 2} (IHX), S-CO{sub 2} to S-CO{sub 2}(Recuperator), S-CO{sub 2} to water (Pre-cooler). By considering all the attributes mentioned above, all existing types of heat exchangers are compared to find a possible alternative to PCHE. The comparing factors are 1) Size(volume), 2) Cost. Plate fin type HEs are considered to be the most competitive heat exchanger regarding the size and the cost after some improvements on the design limit are made. (authors)

  4. 40 CFR 86.1335-90 - Cool-down procedure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... cold cycle exhaust emission test may begin after a cool-down only when the engine oil and water... Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1335-90 Cool-down procedure. (a) This cool-down procedure applies to Otto-cycle and diesel...

  5. 40 CFR 86.1335-90 - Cool-down procedure.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... cold cycle exhaust emission test may begin after a cool-down only when the engine oil and water... Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1335-90 Cool-down procedure. (a) This cool-down procedure applies to Otto-cycle and diesel...

  6. 40 CFR 86.1335-90 - Cool-down procedure.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... cold cycle exhaust emission test may begin after a cool-down only when the engine oil and water... Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1335-90 Cool-down procedure. (a) This cool-down procedure applies to Otto-cycle and diesel...

  7. Cooling wall

    SciTech Connect

    Nosenko, V.I.

    1995-07-01

    Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.

  8. Life Cycle Assessment of Residential Heating and Cooling Systems in Minnesota A comprehensive analysis on life cycle greenhouse gas (GHG) emissions and cost-effectiveness of ground source heat pump (GSHP) systems compared to the conventional gas furnace and air conditioner system

    NASA Astrophysics Data System (ADS)

    Li, Mo

    Ground Source Heat Pump (GSHP) technologies for residential heating and cooling are often suggested as an effective means to curb energy consumption, reduce greenhouse gas (GHG) emissions and lower homeowners' heating and cooling costs. As such, numerous federal, state and utility-based incentives, most often in the forms of financial incentives, installation rebates, and loan programs, have been made available for these technologies. While GSHP technology for space heating and cooling is well understood, with widespread implementation across the U.S., research specific to the environmental and economic performance of these systems in cold climates, such as Minnesota, is limited. In this study, a comparative environmental life cycle assessment (LCA) is conducted of typical residential HVAC (Heating, Ventilation, and Air Conditioning) systems in Minnesota to investigate greenhouse gas (GHG) emissions for delivering 20 years of residential heating and cooling—maintaining indoor temperatures of 68°F (20°C) and 75°F (24°C) in Minnesota-specific heating and cooling seasons, respectively. Eight residential GSHP design scenarios (i.e. horizontal loop field, vertical loop field, high coefficient of performance, low coefficient of performance, hybrid natural gas heat back-up) and one conventional natural gas furnace and air conditioner system are assessed for GHG and life cycle economic costs. Life cycle GHG emissions were found to range between 1.09 × 105 kg CO2 eq. and 1.86 × 10 5 kg CO2 eq. Six of the eight GSHP technology scenarios had fewer carbon impacts than the conventional system. Only in cases of horizontal low-efficiency GSHP and hybrid, do results suggest increased GHGs. Life cycle costs and present value analyses suggest GSHP technologies can be cost competitive over their 20-year life, but that policy incentives may be required to reduce the high up-front capital costs of GSHPs and relatively long payback periods of more than 20 years. In addition

  9. Quantum noise in photothermal cooling

    SciTech Connect

    De Liberato, Simone; Lambert, Neill; Nori, Franco

    2011-03-15

    We study the problem of cooling a mechanical oscillator using the photothermal (bolometric) force. Contrary to previous attempts to model this system, we take into account the noise effects due to the granular nature of photon absorption. We achieve this by developing a Langevin formalism for the motion of the cantilever, valid in the bad-cavity limit, which includes both photon absorption shot noise and the noise due to radiation pressure. This allows us to tackle the cooling problem down to the noise-dominated regime and to find reasonable estimates for the lowest achievable phonon occupation in the cantilever.

  10. Weld electrode cooling study

    NASA Astrophysics Data System (ADS)

    Masters, Robert C.; Simon, Daniel L.

    1999-03-01

    The U.S. auto/truck industry has been mandated by the Federal government to continuously improve their fleet average gas mileage, measured in miles per gallon. Several techniques are typically used to meet these mandates, one of which is to reduce the overall mass of cars and trucks. To help accomplish this goal, lighter weight sheet metal parts, with smaller weld flanges, have been designed and fabricated. This paper will examine the cooling characteristics of various water cooled weld electrodes and shanks used in resistance spot welding applications. The smaller weld flanges utilized in modern vehicle sheet metal fabrications have increased industry's interest in using one size of weld electrode (1/2 inch diameter) for certain spot welding operations. The welding community wants more data about the cooling characteristics of these 1/2 inch weld electrodes. To hep define the cooling characteristics, an infrared radiometer thermal vision system (TVS) was used to capture images (thermograms) of the heating and cooling cycles of several size combinations of weld electrodes under typical production conditions. Tests results will show why the open ended shanks are more suitable for cooling the weld electrode assembly then closed ended shanks.

  11. Cool Shelter

    ERIC Educational Resources Information Center

    Praeger, Charles E.

    2005-01-01

    Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from collecting…

  12. Early developments in solar cooling equipment

    NASA Technical Reports Server (NTRS)

    Price, J. M.

    1978-01-01

    A brief description of a development program to design, fabricate and field test a series of solar operated or driven cooling devices, undertaken by the Marshall Space Flight Center in the context of the Solar Heating and Cooling Demonstration Act of 1974, is presented. Attention is given to two basic design concepts: the Rankine cycle principle and the use of a dessicant for cooling.

  13. BaH molecular spectroscopy with relevance to laser cooling

    NASA Astrophysics Data System (ADS)

    Tarallo, M. G.; Iwata, G. Z.; Zelevinsky, T.

    2016-03-01

    We describe a simple experimental apparatus for laser ablation of barium monohydride (BaH) molecules and the study of their rovibrational spectra relevant to direct laser cooling. BaH is a promising candidate for laser cooling and ultracold fragmentation, both of which are precursors to novel experiments in many-body physics and precision measurement. We present a detailed analysis of the properties of ablation plumes that can improve the understanding of surface ablation and deposition technologies. A range of absorption spectroscopy and collisional thermalization regimes has been studied. We directly measured the Franck-Condon factor of the B 2Σ+(v'=0 ) ←X 2Σ+(v''=1 ) cycling transition. Prospects for production of a high luminosity cryogenic BaH beam are outlined.

  14. Cooled railplug

    DOEpatents

    Weldon, William F.

    1996-01-01

    The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers.

  15. Color-preserving daytime radiative cooling

    NASA Astrophysics Data System (ADS)

    Zhu, Linxiao; Raman, Aaswath; Fan, Shanhui

    2013-11-01

    We introduce a general approach to radiatively lower the temperature of a structure, while preserving its color under sunlight. The cooling effect persists in the presence of considerable convective and conductive heat exchange and for different solar absorptances.

  16. Color-preserving daytime radiative cooling

    SciTech Connect

    Zhu, Linxiao; Raman, Aaswath; Fan, Shanhui

    2013-11-25

    We introduce a general approach to radiatively lower the temperature of a structure, while preserving its color under sunlight. The cooling effect persists in the presence of considerable convective and conductive heat exchange and for different solar absorptances.

  17. Orbital control on carbon cycle alterations and hyperthermal events in a cooling world: the late Early to Mid Eocene record at Possagno (southern Alps, Italy)

    NASA Astrophysics Data System (ADS)

    Galeotti, Simone; Sprovieri, Mario; Moretti, Matteo; Rio, Domenico; Fornaciari, Eliana; Giusberti, Luca; Agnini, Claudia; Backman, Jan; Lanci, Luca; Luciani, Valeria

    2013-04-01

    The late Early Eocene to Middle Eocene ~50-45 Million years ago (Ma) time interval in the middle bathyal, pelagic/hemipelagic succession of the Western Tethys Possagno section (southern Alps, Veneto), contains several episodes of negative carbon isotope excursions (CIEs) and concomitant dissolution of carbonates. These episodes are superimposed on a long term global climate cooling that started at about 51 Ma following the Early Eocene Climatic Optimum (EECO). Spectral analysis indicates that CIEs and dissolution events are paced by orbital forcing, confirming the global significance of previous finding on the same interval from Western and Southern Atlantic and Equatorial Pacific sites. The frequency and magnitude of CIEs through time is controlled by long-term modulations of orbital parameters, including long eccentricity (400 kyr) and a 1.2 million year modulation. Highest frequency of events - at the orbital scale - is observed across the EECO, which provides an observational basis to validate theoretical models predicting a threshold effect resulting from orbital forcing superimposed on gradually changing mean global boundary conditions. The observation of the 1.2 million year beat (long-term modulation of obliquity) together with previously published observation of enhanced obliquity (41 kyr) forcing across major CIEs and dissolution intervals indicates that high latitude feedbacks to orbital forcing played a fundamental role in the emplacement of the hyperthermals. The observed orbital forcing signature closely match that of early Eocene hyperthermals, suggesting similar driving processes.

  18. Cool School.

    ERIC Educational Resources Information Center

    Stephens, Suzanne

    1980-01-01

    The design for Floyd Elementary School in Miami (Florida) seeks to harness solar energy to provide at least 70 percent of the annual energy for cooling needs and 90 percent for hot water. (Author/MLF)

  19. Revised estimates of the ocean energy cycle and the key role of the western boundary in the APE to KE conversion due to high latitude cooling

    NASA Astrophysics Data System (ADS)

    Tailleux, Remi

    2014-05-01

    The ocean energy cycle is a key aspect of the ocean circulation, and has been traditionally framed in terms of Lorenz (1955) theory of available potential energy. However, the latest available observational estimate of the ocean energy cycle is due to Oort and Peixoto (1994) and is now very dated. Moreover, the latter estimate relies on the so-called Lorenz quasi-geostrophic approximation, which is known to be very inaccurate. Oort and Peixoto also neglected the internal energy contribution to the total available potential energy, which is now understood to be far from negligible, and to account for up to 40 percent of the total APE. The purpose of this work is to revisit observational estimates of the ocean energy cycle by taking advantage of a newly developed APE framework, as well as of the many new available observational products for temperature, salinity and surface buoyancy fluxes. In contrast to previous frameworks, our APE framework (Tailleux, 2013) relies on a physically well defined local APE definition, which is valid for a binary Boussinesq or fully compressible fluid with an arbitrary nonlinear equation of state. As part of our approach, we also developed a new fast and accurate way to construct Lorenz reference state of minimum potential energy, based on using the joint probability distribution function for temperature and salinity. Results will be presented for a variety of observational products, as well as for the ECCO2 ocean state estimate. The role of the deep western boundary as the place where the APE created by high latitude is converted into kinetic energy (KE) as part of driving the Atlantic meridional overturning circulation will be emphasized. References: Tailleux, R., 2013: Available potential energy density for a multicomponent Boussinesq fluid with arbitrary nonlinear equation of state.J. Fluid Mech., 735,499-518. Sijp, W., J.M.Gregory, R. Tailleux, P. Spence, 2012: The key role of the western boundary in linking the AMOC strength to

  20. Up-cycling waste glass to minimal water adsorption/absorption lightweight aggregate by rapid low temperature sintering: optimization by dual process-mixture response surface methodology.

    PubMed

    Velis, Costas A; Franco-Salinas, Claudia; O'Sullivan, Catherine; Najorka, Jens; Boccaccini, Aldo R; Cheeseman, Christopher R

    2014-07-01

    Mixed color waste glass extracted from municipal solid waste is either not recycled, in which case it is an environmental and financial liability, or it is used in relatively low value applications such as normal weight aggregate. Here, we report on converting it into a novel glass-ceramic lightweight aggregate (LWA), potentially suitable for high added value applications in structural concrete (upcycling). The artificial LWA particles were formed by rapidly sintering (<10 min) waste glass powder with clay mixes using sodium silicate as binder and borate salt as flux. Composition and processing were optimized using response surface methodology (RSM) modeling, and specifically (i) a combined process-mixture dual RSM, and (ii) multiobjective optimization functions. The optimization considered raw materials and energy costs. Mineralogical and physical transformations occur during sintering and a cellular vesicular glass-ceramic composite microstructure is formed, with strong correlations existing between bloating/shrinkage during sintering, density and water adsorption/absorption. The diametrical expansion could be effectively modeled via the RSM and controlled to meet a wide range of specifications; here we optimized for LWA structural concrete. The optimally designed LWA is sintered in comparatively low temperatures (825-835 °C), thus potentially saving costs and lowering emissions; it had exceptionally low water adsorption/absorption (6.1-7.2% w/wd; optimization target: 1.5-7.5% w/wd); while remaining substantially lightweight (density: 1.24-1.28 g.cm(-3); target: 0.9-1.3 g.cm(-3)). This is a considerable advancement for designing effective environmentally friendly lightweight concrete constructions, and boosting resource efficiency of waste glass flows. PMID:24871934

  1. Acoustic power absorption and enhancement generated by slow and fast MHD waves. Evidence of solar cycle velocity/intensity amplitude changes consistent with the mode conversion theory

    NASA Astrophysics Data System (ADS)

    Simoniello, R.; Finsterle, W.; García, R. A.; Salabert, D.; Jiménez, A.; Elsworth, Y.; Schunker, H.

    2010-06-01

    We used long duration, high quality, unresolved (Sun-as-a star) observations collected by the ground based network BiSON and by the instruments GOLF and VIRGO on board the ESA/NASA SOHO satellite to search for solar-cycle-related changes in mode characteristics in velocity and continuum intensity for the frequency range between 2.5 mHz <ν< 6.8 mHz. Over the ascending phase of solar cycle 23 we found a suppression in the p-mode amplitudes both in the velocity and intensity data between 2.5 mHz <ν< 4.5 mHz with a maximum suppression for frequencies in the range between 2.5 mHz <ν< 3.5 mHz. The size of the amplitude suppression is 13 ± 2 per cent for the velocity and 9 ± 2 per cent for the intensity observations. Over the range of 4.5 mHz <ν< 5.5 mHz the findings hint within the errors to a null change both in the velocity and intensity amplitudes. At still higher frequencies, in the so called High-frequency Interference Peaks (HIPs) between 5.8 mHz <ν< 6.8 mHz, we found an enhancement in the velocity amplitudes with the maximum 36 ± 7 per cent occurring for 6.3 mHz <ν< 6.8 mHz. However, in intensity observations we found a rather smaller enhancement of about 5 ± 2 per cent in the same interval. There is evidence that the frequency dependence of solar-cycle velocity amplitude changes is consistent with the theory behind the mode conversion of acoustic waves in a non-vertical magnetic field, but there are some problems with the intensity data, which may be due to the height in the solar atmosphere at which the VIRGO data are taken.

  2. Solar Absorption Refrigeration System for Air-Conditioning of a Classroom Building in Northern India

    NASA Astrophysics Data System (ADS)

    Agrawal, Tanmay; Varun; Kumar, Anoop

    2015-10-01

    Air-conditioning is a basic tool to provide human thermal comfort in a building space. The primary aim of the present work is to design an air-conditioning system based on vapour absorption cycle that utilizes a renewable energy source for its operation. The building under consideration is a classroom of dimensions 18.5 m × 13 m × 4.5 m located in Hamirpur district of Himachal Pradesh in India. For this purpose, cooling load of the building was calculated first by using cooling load temperature difference method to estimate cooling capacity of the air-conditioning system. Coefficient of performance of the refrigeration system was computed for various values of strong and weak solution concentration. In this work, a solar collector is also designed to provide required amount of heat energy by the absorption system. This heat energy is taken from solar energy which makes this system eco-friendly and sustainable. A computer program was written in MATLAB to calculate the design parameters. Results were obtained for various values of solution concentrations throughout the year. Cost analysis has also been carried out to compare absorption refrigeration system with conventional vapour compression cycle based air-conditioners.

  3. Deep mine cooling system

    SciTech Connect

    Conan, J.

    1984-11-06

    A deep mine cooling system comprising a compressor supplied with air and rotatively driven by a motor and an expansion turbine supplied with compressed air from said compressor and driving an actuating unit, wherein the compressed air, after leaving the compressor but prior to reaching the expansion turbine, passes through a steam generator whose output provides the energy required to operate an absorption refrigeration machine used to cool utility water for mining, said compressed air on leaving the steam generator going to a first heat exchanger in which it yields calories to a water circuit comprising a second heat exchanger, said second heat exchanger giving off the calories absorbed by the water in the first heat exchanger to the air fed by the second heat exchanger to a drying cell that is regenerated by said air from the second heat exchanger, said drying cell being part of a set of two cells working in alternation, the other cell in the set receiving the compressed air from the first heat exchanger, such that the compressed air is fed to said expansion turbine after leaving said drying unit, and wherein the air exhausted from said expansion turbine is sent to a third heat exchanger after which it is distributed according to the needs of the mine, said third exchanger being traversed by the water collected in the mine, cooled in said exchanger and circulated upon leaving said exchanger to meet the cool water requirements of the mine.

  4. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  5. Aqueous absorption fluids. Annual report, July 1989-October 1990

    SciTech Connect

    Langeliers, J.; Chandler, T.; Rockenfeller, U.

    1990-11-01

    The report describes the third year of study of aqueous-based working fluids that will allow air-cooled absorption chiller operation. The successful development of such fluids will eliminate the need for cooling towers in gas-fired chiller equipment for residential and unitary markets and possibly allow for building heating with absorber heat. The thermophysical property measurements were completed and the vapor pressure and specific heat data were used to compute the enthalpy of LB621-H2O solutions. Solution film heat transfer coefficients were measured in the test sorber apparatus and a dramatic increase in film heat transfer was observed in the presence of heat transfer additives. Measured equilibrium and film heat transfer data were used in the single-stage absorption cycle computer model to analyze the potential performance of LB621-H2O; the analysis confirmed the superiority of LB621-H2O as a single-stage working fluid. In addition, thermal stability and corrosion rate tests demonstrated that LB621-H2O is stable and non-corrosive in a single-stage absorption chiller environment.

  6. Cooled railplug

    DOEpatents

    Weldon, W.F.

    1996-05-07

    The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers. 10 figs.

  7. Cooling Vest

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Because quadriplegics are unable to perspire below the level of spinal injury, they cannot tolerate heat stress. A cooling vest developed by Ames Research Center and Upjohn Company allows them to participate in outdoor activities. The vest is an adaptation of Ames technology for thermal control garments used to remove excess body heat of astronauts. The vest consists of a series of corrugated channels through which cooled water circulates. Its two outer layers are urethane coated nylon, and there is an inner layer which incorporates the corrugated channels. It can be worn as a backpack or affixed to a wheelchair. The unit includes a rechargeable battery, mini-pump, two quart reservoir and heat sink to cool the water.

  8. Cholesterol absorption.

    PubMed

    Ostlund, Richard E

    2002-03-01

    Cholesterol absorption is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol absorption and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol absorption is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol absorption when dietary intake is high. New clinical treatments based on better understanding of absorption physiology are likely to substantially improve clinical cholesterol management in the future. PMID:17033296

  9. The development of a solar residential heating and cooling system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The MSFC solar heating and cooling facility was assembled to demonstrate the engineering feasibility of utilizing solar energy for heating and cooling buildings, to provide an engineering evaluation of the total system and the key subsystems, and to investigate areas of possible improvement in design and efficiency. The basic solar heating and cooling system utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating, and an absorption cycle air conditioner for space cooling. A complete description of all systems is given. Development activities for this test system included assembly, checkout, operation, modification, and data analysis, all of which are discussed. Selected data analyses for the first 15 weeks of testing are included, findings associated with energy storage and the energy storage system are outlined, and conclusions resulting from test findings are provided. An evaluation of the data for summer operation indicates that the current system is capable of supplying an average of 50 percent of the thermal energy required to drive the air conditioner. Preliminary evaluation of data collected for operation in the heating mode during the winter indicates that nearly 100 percent of the thermal energy required for heating can be supplied by the system.

  10. Closed loop steam cooled airfoil

    SciTech Connect

    Widrig, Scott M.; Rudolph, Ronald J.; Wagner, Gregg P.

    2006-04-18

    An airfoil, a method of manufacturing an airfoil, and a system for cooling an airfoil is provided. The cooling system can be used with an airfoil located in the first stages of a combustion turbine within a combined cycle power generation plant and involves flowing closed loop steam through a pin array set within an airfoil. The airfoil can comprise a cavity having a cooling chamber bounded by an interior wall and an exterior wall so that steam can enter the cavity, pass through the pin array, and then return to the cavity to thereby cool the airfoil. The method of manufacturing an airfoil can include a type of lost wax investment casting process in which a pin array is cast into an airfoil to form a cooling chamber.

  11. [Ecological and radio-ecological effects from long-term use of the lake Kyzyl-Tash as a cooling reservoir by the nuclear fuel cycle facility].

    PubMed

    Smagin, A I

    2010-01-01

    This review introduces long-term study findings on ecological and radiation induced regime of the water reservoir - lake Kyzyl-Tash (R-2) - used as a heat sink of nuclear-power reactors in the Southern Urals from 1948 through 2008. It was exhibited that water reservoir exploitation by the nuclear fuel cycle facility "Mayak" PA resulted in hydrological, thermal, hydrochemical and radiological ecosystem regimes changes. The central radioactive substances depot in the water reservoir was determined to be the upper 20-30 cm bed silt layers, contamination density of which in 1980-1990s amounted on average approximately 0.2 PBq/km2 (about 5 kKu/km2). Some regularities of radionuclide distribution in bed sediments and biota were ascertained. Dose estimates from ionizing exposure to fish inhabited the water reservoir were experimentally made. Dose contribution was mainly due to incorporated beta-emitters amounted up to 2-3 Gy/y in 1980s. The leading role in the reservoir life belonged to phytoplankton with its algal nuisance periodicity constituting 5-6 years for blue-green and diatomic algae, and 2-3 years for green algae. During periods of the highest development pressure phytoplankton productive capacity in the reservoir was by an order of magnitude greater compared to control water reservoirs of the region. Combined long-term impact of radiological and chemical factors did not cause irreversible changes either in fish populations or ecological system in general. It can be proved by the fact that during 1970-1980s the water reservoir R-2 was inhabited by such cleanness indicators as crawfish (Astacus leptodactylus) and shellfish (Anodonta cygnea L.). On reducing of thermal and chemical pressure in the end of 1980s some processes observed gave evidence of ecosystem restoration in the lake Kyzyl-Tash. At the present moment the situation of the water reservoir exploiting as a heat sink is stabilized with preserved self-cleaning capacity. PMID:20968056

  12. Laser cooling, slowing and trapping of a diatomic molecule

    NASA Astrophysics Data System (ADS)

    Barry, John

    2015-05-01

    Roughly three decades ago, laser cooling and trapping succeeded in producing ultracold ions and atoms, sparking a revolution in atomic physics and subsequently becoming workhorse techniques within the field. These techniques require a ``cycling transition,'' where the particle of interest is repeatedly driven by a photon into an excited electronic state and quickly decays back to the initial ground state, allowing the process to repeat. Because photon absorption transfers momentum to the particle, application of force is possible. Adjusting the geometry and frequency of the applied photons allows creation of a damping (cooling) force. Further addition of a quadrupole magnetic field allows for a restoring (trapping) force. Prior to this thesis, straightforward extension of these methods to molecules was considered a practical impossibility; electronic decays in molecules tend to populate multiple rotational and vibrational states, preventing creation of a cycling transition. While a variety of ultracold molecular species is desirable to satisfy a range of applications, the only other production method is limited to species where the constituent atoms are themselves amenable to laser cooling. For other species, a different technique is required. Here we outline the methods and experiments in which laser cooling and trapping were first applied to molecules. By careful molecule choice, by using a cooling transition that exploits selection rules, and by counteracting dark states with a magnetic field, we create a cycling transition for the diatomic molecule strontium monofluoride (SrF). We show the power of this technique by demonstrating Doppler and sub-Doppler cooling in 1-D, radiation pressure slowing and stopping of a molecular beam, and finally a 3-D magneto-optical trap (MOT). Our MOT produces the coldest trapped sample of directly-cooled molecules to date, with a temperature of T ~ 2.5 mK. This method is viable for several classes of diatomic molecules with a

  13. Photoexcitation and cooling of positronium

    SciTech Connect

    Dermer, C.D.; Howell, R.H.; Jones, K.M.; Liang, E.P.; Magnotta, F.; Ziock, K.P.

    1988-08-01

    Our demonstration of multiple-photon resonant cycling between the 1/sup 3/S and 2/sup 3/P states of ortho-Positronium (oPs) makes possible the production of cold positronium (Ps) through the technique of laser cooling. A simplified analysis of magnetic mixing in excited-state Ps is given. This effect is important both as a diagnostic of resonant cycling and Ps cooling. The significance of cold Ps in fine structure measurements and the formation of a Bose-Einstein condensate is discussed. 13 refs., 3 figs.

  14. Surface and in-depth characterization of lithium-ion battery cathodes at different cycle states using confocal micro-X-ray fluorescence-X-ray absorption near edge structure analysis

    NASA Astrophysics Data System (ADS)

    Menzel, Magnus; Schlifke, Annalena; Falk, Mareike; Janek, Jürgen; Fröba, Michael; Fittschen, Ursula Elisabeth Adriane

    2013-07-01

    The cathode material LiNi0.5Mn1.5O4 for lithium-ion batteries has been studied with confocal micro-X-ray fluorescence (CMXRF) combined with X-ray absorption near edge structure (XANES) at the Mn-K edge and the Ni-K edge. This technique allows for a non-destructive, spatially resolved (x, y and z) investigation of the oxidation states of surface areas and to some extent of deeper layers of the electrode. Until now CMXRF-XANES has been applied to a limited number of applications, mainly geo-science. Here, we introduce this technique to material science applications and show its performance to study a part of a working system. A novel mesoporous LiNi0.5Mn1.5O4 material was cycled (charged and discharged) to investigate the effects on the oxidation states at the cathode/electrolyte interface. With this approach the degradation of Mn3 + to Mn4 + only observable at the surface of the electrode could be directly shown. The spatially resolved non-destructive analysis provides knowledge helpful for further understanding of deterioration and the development of high voltage battery materials, because of its nondestructive nature it will be also suitable to monitor processes during battery cycling.

  15. Development of New Air-Cooled Heat Pump Chiller 'Compact Cube'

    NASA Astrophysics Data System (ADS)

    Ookoshi, Yasushi; Ito, Takuya; Yamaguchi, Hiroshi; Kato, Yohei; Ochiai, Yasutaka; Tanaka, Kosuke; Uji, Yoshihiro; Nakayama, Hiroshi

    Further improvement of the performance is requested to air-cooled heat pump chiller from the viewpoint of the global warming prevention. Smaller unit is needed to facilitate the renewal from absorption chiller to air-cooled heat pump chiller. To meet such needs, we developed compact new air-cooled heat pump chiller with high efficiency, 'Compact cube'. The developed machine is side-flow type with U-shaped fin and tube heat exchangers. With this structure, the uniform air velocity, high packed density of the heat exchangers, and the unit miniaturization have been implemented. The refrigeration cycle with two-evaporating temperature has also been implemented. The cooling COP of this cycle is 2% higher compared with conventional one-evaporating temperature cycle because of the rise of average evaporating temperature. In a new model, a new control system, which controls both capacity of compressors and air flow rate corresponding to heat load, has been implemented. As a result, the developed machine achieved IPLV(Integrated Part load Value) to 6.2(MCHV-P1800AE) which is 29% better than the conventional unit.

  16. Stochastic cooling

    SciTech Connect

    Bisognano, J.; Leemann, C.

    1982-03-01

    Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron.

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

    NASA Astrophysics Data System (ADS)

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

    1980-12-01

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

  18. Laser cooling of solids

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2010-08-01

    Laser cooling of solids, sometimes also known as optical refrigeration, is a fast developing area of optical science, investigating the interaction of light with condensed matter. Apart from being of fundamental scientific interest, this topic addresses a very important practical issue: design and construction of laser pumped solid-state cryocoolers, which are compact, free from mechanical vibrations, moving parts, fluids and can cause only low electromagnetic interference in the cooled area. The optical cryocooler has a broad area of applications such as in the development of magnetometers for geophysical sensors, in biomedical sensing and can be beneficial for satellite instrumentations and small sensors, where compactness and the lack of vibrations are very important. Simply, a laser cooler works on the conversion of low energy pump photons into high-energy anti-Stokes fluorescence photons by extracting some of the phonons (heat energy) in a material. That is, the process of laser cooling of solids is based on anti-Stokes fluorescence also known as luminescence upconversion, when light quanta in the red tail of the absorption spectrum are absorbed from a pump laser, and blue-shifted photons are spontaneously emitted. The extra energy extracted from the solid-state lattice in the form of the phonons is the quanta of vibrational energy which generates heat. The idea to cool solids with anti-Stokes fluorescence was proposed in 1929 by Peter Pringsheim and first demonstrated experimentally by Epstein's research team in 1995. In 1999, Steven Bowman proposed to use the optical refrigeration by anti-Stokes fluorescence within the laser medium to balance the heat generated by the Stokes shifted stimulated emission in a high-power solid-state bulk laser. Such a laser without internal heating named radiation-balanced or athermal laser was experimentally demonstrated for the first time in 2002. At the present time laser cooling of solids can be largely divided into three

  19. Radial turbine cooling

    NASA Technical Reports Server (NTRS)

    Roelke, Richard J.

    1992-01-01

    Radial turbines have been used extensively in many applications including small ground based electrical power generators, automotive engine turbochargers and aircraft auxiliary power units. In all of these applications the turbine inlet temperature is limited to a value commensurate with the material strength limitations and life requirements of uncooled metal rotors. To take advantage of all the benefits that higher temperatures offer, such as increased turbine specific power output or higher cycle thermal efficiency, requires improved high temperature materials and/or blade cooling. Extensive research is on-going to advance the material properties of high temperature superalloys as well as composite materials including ceramics. The use of ceramics with their high temperature potential and low cost is particularly appealing for radial turbines. However until these programs reach fruition the only way to make significant step increases beyond the present material temperature barriers is to cool the radial blading.

  20. Performance Analysis of XCPC Powered Solar Cooling Demonstration Project

    NASA Astrophysics Data System (ADS)

    Widyolar, Bennett K.

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

  1. Methods of beam cooling

    SciTech Connect

    Sessler, A.M.

    1996-02-01

    Diverse methods which are available for particle beam cooling are reviewed. They consist of some highly developed techniques such as radiation damping, electron cooling, stochastic cooling and the more recently developed, laser cooling. Methods which have been theoretically developed, but not yet achieved experimentally, are also reviewed. They consist of ionization cooling, laser cooling in three dimensions and stimulated radiation cooling.

  2. Simulation Analysis of the NH3-H2O Two-Stage Desorption Type Absorption Refrigerator Driven by Low Grade Waste Heat

    NASA Astrophysics Data System (ADS)

    Takei, Toshitaka; Kimijima, Shinji; Saito, Kiyoshi; Kawai, Sunao

    Recently, from a view point of the environmental protection, NH3-H2O absorption refrigerator attracts attention in the field of the refrigeration and the air conditioning. Since NH3-H2O absorption refrigerators can produce below zero degree products, this type of refrigerators have many usages in the refrigeration. This paper describes the two-stage desorption type absorption refrigerator driven by waste heat of co-generation system. There are two absorption cycles which are operated under the condition of the different pressure and the solution concentration in this absorption refrigerator. It becomes essential to clarify the characteristics of this absorption refrigerator since the operating conditions are changed through out the year in the co-generation system. Particularly, in this paper, we investigate the effects of evaporating temperature of ammonia and cooling water temperature for the performance of this absorption refrigerator by simulation analysis. Through out the research, it is shown that COP can be improved when evaporating temperature is higher or cooling water temperature is lower. In addition to this, it is obtained that the necessary temperature of hot water becomes lower in such condition. As a result, the effectiveness of using this absorption refrigerator under the operating condition of which hot watertemperatureis90∼100[°C] and evaporating temperature is -10∼- 20 [°C] is clarified

  3. Cool Sportswear

    NASA Technical Reports Server (NTRS)

    1982-01-01

    New athletic wear design based on the circulating liquid cooling system used in the astronaut's space suits, allows athletes to perform more strenuous activity without becoming overheated. Techni-Clothes gear incorporates packets containing a heat-absorbing gel that slips into an insulated pocket of the athletic garment and is positioned near parts of the body where heat transfer is most efficient. A gel packet is good for about one hour. Easily replaced from a supply of spares in an insulated container worn on the belt. The products, targeted primarily for runners and joggers and any other athlete whose performance may be affected by hot weather, include cooling headbands, wrist bands and running shorts with gel-pack pockets.

  4. Inhomogeneous thermal conductivity enhances thermoelectric cooling

    NASA Astrophysics Data System (ADS)

    Lu, Tingyu; Zhou, Jun; Li, Nianbei; Yang, Ronggui; Li, Baowen

    2014-12-01

    We theoretically investigate the enhancement of thermoelectric cooling performance in thermoelectric refrigerators made of materials with inhomogeneous thermal conductivity, beyond the usual practice of enhancing thermoelectric figure of merit (ZT) of materials. The dissipation of the Joule heat in such thermoelectric refrigerators is asymmetric which can give rise to better thermoelectric cooling performance. Although the thermoelectric figure of merit and the coefficient-of-performance are slightly enhanced, both the maximum cooling power and the maximum cooling temperature difference can be enhanced significantly. This finding can be used to increase the heat absorption at the cold end. We further find that the asymmetric dissipation of Joule heat leads to thermal rectification.

  5. Parametric analysis of a double-effect steam absorption chiller

    NASA Astrophysics Data System (ADS)

    Mohammed Salih Ahmed, Mojahid Sid Ahmed; Gilani, Syed Ihtsham Ul-Haq

    2012-06-01

    The development in the field of refrigeration and cooling systems based on absorption cycles has attained its own internal dynamic in the last decade. A major obstacle for developing model is the lack of available component specifications. These specifications are commonly proprietary of the chiller's manufacturers and normally the available information is not sufficient. This work presented a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations. The chiller studied is 1250 RT (Refrigeration Tons) using lithium bromide -water as working pair. The mathematical equations that govern the operation of the steam absorption chiller are developed, and from the available design data the values of the overall heat transfer coefficient multiplied by the heat exchanger surface area and the characteristics of each component of the absorption chiller at the design point are calculated. For thermo physical and thermodynamic properties for lithium bromide-water solution, set of computationally efficient formulations are used. The model gives the required information about temperature, concentration, and flow rate at each state point of the system. The model calculates the heat load at each component as well as the performance of the system.

  6. The effect of pre-cooling intensity on cooling efficiency and exercise performance.

    PubMed

    Bogerd, Nina; Perret, Claudio; Bogerd, Cornelis P; Rossi, René M; Daanen, Hein A M

    2010-05-01

    Although pre-cooling is known to enhance exercise performance, the optimal cooling intensity is unknown. We hypothesized that mild cooling opposed to strong cooling circumvents skin vasoconstriction and thermogenesis, and thus improves cooling efficiency reflected in improved time to exhaustion. Eight males undertook three randomized trials, consisting of a pre-cooling and an exercise session. During the pre-cooling, performed in a room of 24.6 +/- 0.4 degrees C and 24 +/- 6% relative humidity, participants received either 45 min of mild cooling using an evaporative cooling shirt or strong cooling using an ice-vest. A no-cooling condition was added as a control. Subsequent cycling exercise was performed at 65%[Vdot]O(2peak) in a climatic chamber of 29.3 +/- 0.2 degrees C and 80 +/- 3% relative humidity. During the pre-cooling session, mild and strong cooling decreased the skin blood flow compared with the control. However, no differences were observed between mild and strong cooling. No thermogenesis was observed in any conditions investigated. The reduction of body heat content after pre-cooling was two times larger with strong cooling (39.5 +/- 8.4 W . m(-2)) than mild cooling (21.2 +/- 5.1 W . m(-2)). This resulted in the greatest improvement in time to exhaustion with strong cooling. We conclude that the cooling intensities investigated had a similar effect on cooling efficiency (vasoconstriction and thermogenesis) and that the improved performance after strong cooling is attributable to the greater decrease in body heat content. PMID:20496225

  7. Absorption refrigeration machine driven by solar heat

    NASA Astrophysics Data System (ADS)

    Keizer, C.; Liem, S. H.

    1980-04-01

    A mathematical model of a single and a two stage solar absorption refrigeration system is developed in which data of collectors and weather data can be implicated. The influence of the generator, the absorber efficiencies, and the cooling temperature on the coefficient of performance (COP) of a single and two stage absorption refrigeration process are investigated. For low generator temperatures the absorber efficiency has more influence on COP than the generator efficiency. Only spectral selective double window and high performance collectors can be used for air cooled solar absorption refrigeration systems at an evaporator temperature of -5 C. It is concluded that a water cooled solar absorption refrigeration system in combination with a solar tapwater installation for household use can be achieved with 6 to 8 square meters high performance collector area.

  8. Debuncher Cooling Limitations to Stacking

    SciTech Connect

    Halling, Mike

    1991-08-13

    During the January studies period we performed studies to determine the effect that debuncher cooling has on the stacking rate. Two different sets of measurements were made separated by about a week. Most measurements reported here are in PBAR log 16, page 243-247. These measurements were made by changing the accelerator timeline to give about 6 seconds between 29's, and then gating the cooling systems to simulate reduced cycle times. For the measurement of the momentum cooling effectiveness the gating switches could not be made to work, so the timeline was changed for each measurement. The cooling power of all three systems was about 800 watts for the tests reported here. We now regularly run at 1200 watts per system.

  9. REACTOR COOLING

    DOEpatents

    Quackenbush, C.F.

    1959-09-29

    A nuclear reactor with provisions for selectively cooling the fuel elements is described. The reactor has a plurality of tubes extending throughout. Cylindrical fuel elements are disposed within the tubes and the coolant flows through the tubes and around the fuel elements. The fuel elements within the central portion of the reactor are provided with roughened surfaces of material. The fuel elements in the end portions of the tubes within the reactor are provlded with low conduction jackets and the fuel elements in the region between the central portion and the end portions are provided with smooth surfaces of high heat conduction material.

  10. Annual DOE Active Solar Heating and Cooling Contractors Review meeting

    NASA Astrophysics Data System (ADS)

    1981-09-01

    Ninety three project summaries dicussing the following aspects of active solar heating and cooling are presented: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology.

  11. Solar powered absorption air conditioning

    NASA Astrophysics Data System (ADS)

    Vardon, J. M.

    1980-04-01

    Artificial means of providing or removing heat from the building are discussed along with the problem of the appropriate building design and construction for a suitable heat climate inside the building. The use of a lithium bromide-water absorption chiller, powered by a hot water store heated by an array of stationary flat collectors, is analyzed. An iterative method of predicting the cooling output from a LiBr-water absorption refrigeration plant having variable heat input is described and a model allowing investigation of the performance of a solar collector and thermal storage system is developed.

  12. X-Ray spectroscopy of cooling flows

    NASA Technical Reports Server (NTRS)

    Prestwich, Andrea

    1996-01-01

    Cooling flows in clusters of galaxies occur when the cooling time of the gas is shorter than the age of the cluster; material cools and falls to the center of the cluster potential. Evidence for short X-ray cooling times comes from imaging studies of clusters and X-ray spectroscopy of a few bright clusters. Because the mass accretion rate can be high (a few 100 solar mass units/year) the mass of material accumulated over the lifetime of a cluster can be as high as 10(exp 12) solar mass units. However, there is little evidence for this material at other wavelengths, and the final fate of the accretion material is unknown. X-ray spectra obtained with the Einstein SSS show evidence for absorption; if confirmed this result would imply that the accretion material is in the form of cool dense clouds. However ice on the SSS make these data difficult to interpret. We obtained ASCA spectra of the cooling flow cluster Abell 85. Our primary goals were to search for multi-temperature components that may be indicative of cool gas; search for temperature gradients across the cluster; and look for excess absorption in the cooling region.

  13. Interferometric Laser Cooling of Atomic Rubidium.

    PubMed

    Dunning, Alexander; Gregory, Rachel; Bateman, James; Himsworth, Matthew; Freegarde, Tim

    2015-08-14

    We report the 1D cooling of ^{85}Rb atoms using a velocity-dependent optical force based upon Ramsey matter-wave interferometry. Using stimulated Raman transitions between ground hyperfine states, 12 cycles of the interferometer sequence cool a freely moving atom cloud from 21 to 3 μK. This pulsed analog of continuous-wave Doppler cooling is effective at temperatures down to the recoil limit; with augmentation pulses to increase the interferometer area, it should cool more quickly than conventional methods and be more suitable for species that lack a closed radiative transition. PMID:26317719

  14. Interferometric Laser Cooling of Atomic Rubidium

    NASA Astrophysics Data System (ADS)

    Dunning, Alexander; Gregory, Rachel; Bateman, James; Himsworth, Matthew; Freegarde, Tim

    2015-08-01

    We report the 1D cooling of 85Rb atoms using a velocity-dependent optical force based upon Ramsey matter-wave interferometry. Using stimulated Raman transitions between ground hyperfine states, 12 cycles of the interferometer sequence cool a freely moving atom cloud from 21 to 3 μ K . This pulsed analog of continuous-wave Doppler cooling is effective at temperatures down to the recoil limit; with augmentation pulses to increase the interferometer area, it should cool more quickly than conventional methods and be more suitable for species that lack a closed radiative transition.

  15. Characteristics of Single/Double-Effect Combination Absorption Refrigerator

    NASA Astrophysics Data System (ADS)

    Kimijima, Shingi; Waragai, Shisei; Uekusa, Tsuneo; Nakao, Masaki; Kawai, Sunao

    This report refers to the single/double-effect combination absorption refrigerator, which is driven by waste heat from phosphoric acid fuel cells, and investigates the influence of heat supply conditions, for the purpose of the effectual utilization of the low grade waste heat such as hot water (60~90([°C]). Since waste heat from fuel cells is recovered in two forms of steam and hot water, there is a characteristic of mutual intervention between steam and hot water in absorption refrigeration cycle. For effective use of waste heat, it becomes necessary to clarify this characteristic of mutual intervention. Accordingly, we inquire the effect of heat supply conditions on above mentioned characteristic by simulation. In addition to this, the cooling performance of the absorption refrigerators with two different ways to use hot water (preheating of solution type and generating refrigerant vapor in the low temperature generator type) is investigated. Through out the research, some knowledges for effective use of low grade waste heat are obtained

  16. Measuring the anti-Stokes luminescence of CdSe/ZnS quantum dots for laser cooling applications

    NASA Astrophysics Data System (ADS)

    Fontenot, Ross S.; Mathur, Veerendra K.; Barkyoumb, John H.; Mungan, Carl E.; Tran, Thanh N.

    2016-05-01

    The first demonstration of laser cooling of solids was of an ytterbium doped fluorozirconate glass. While this groundbreaking work successfully showed that it is possible to cool solids using laser cooling, rare-earth materials are governed by Boltzmann statistics limiting their cooling ability to about 100 K. Direct-bandgap semiconductors, on the other hand, are governed by Fermi-Dirac statistics, which allows for a theoretical cooling limit of 10 K as well as higher cooling efficiencies. Recently, it was demonstrated that it is possible to cool CdS nanoribbons by 40 K. That success was attributed to CdS strong electron-phonon coupling, which makes it possible to resonantly annihilate more than one longitudinal optical phonon during each up conversion cycle. To further increase the cooling power, large external quantum efficiency is required. A nanostructure is preferred because it creates confined excitons of tunable wavelength and reduces the self-absorption of the anti-Stokes fluorescence owing to the shorter path length for photons to escape the crystal. However, organically passivated quantum dots have a low quantum yield due to surface related trap states. A core-shell nanostructure alleviates this problem by passivating the surface trap states and protecting against environmental changes and photo-oxidative degradation. As such, we chose to investigate CdSe/ZnS core shell structure for laser cooling applications. This article highlights the measurement of the anti-Stokes luminescence, the dependence of the laser wavelength on the anti-Stokes emission of colloidal quantum dots, and the successful incorporation of CdSe/ZnS into polymers.

  17. Thermochemical cycles

    NASA Technical Reports Server (NTRS)

    Funk, J. E.; Soliman, M. A.; Carty, R. H.; Conger, W. L.; Cox, K. E.; Lawson, D.

    1975-01-01

    The thermochemical production of hydrogen is described along with the HYDRGN computer program which attempts to rate the various thermochemical cycles. Specific thermochemical cycles discussed include: iron sulfur cycle; iron chloride cycle; and hybrid sulfuric acid cycle.

  18. Solar Induced Climate Changes and Cooling of the Earth

    NASA Astrophysics Data System (ADS)

    Yousef, Shahinaz M.

    2011-06-01

    Evidences are given for the cooling effect induced by solar weak cycles. It is forecasted that the coming solar cycle number 24, which has started on January 2008, would be very weak. This cycle would be followed by several weak cycles. Its very start on January 2008 have induced a climate change that forced global cooling, Indeed all global temperature monitors have shown temperature drops. The GISS monitor showed a 0.75°C drop between January 2007 and January 2008. This sharp temperature drop characterizes cooling induced by weak cycles as was evident by historical temperature records. It also happened in the right exact timing of the start of cycle 24. This cooling is real and could last for some time. The cooling well width is location dependant. Last January cooling left many countries in deep freeze. Cooling is very serious and can destroy crops and cause famines. This cooling is instrumentally recorded. This is an appeal to scientists to consider the present cooling seriously, after all the truth ought to be followed. Alert is also given to the reaponsible authorities to work promptly to choose the proper crops that can tolerate the cold otherwise it would be a disaster worldwide.

  19. Preliminary concepts for high-temperature mold heating and cooling

    SciTech Connect

    Larson, J.P.

    1990-12-01

    The feasibility and limitations of various methods for mold heating and cooling were investigated. Two methods were chosen for evaluation: electrical heating and water cooling, and electrical heating and heat pipe conduction cooling. A model mold of each method was built. Test results indicated that the electrical heating and circulated water cooling was the better method. An injection mold utilizing this method was fabricated and temperature-cycled between 300 and 770{degree}F. 1 ref., 2 figs., 7 tabs.

  20. Laser cooling by collisional redistribution of radiation.

    PubMed

    Vogl, Ulrich; Weitz, Martin

    2009-09-01

    The general idea that optical radiation may cool matter was put forward 80 years ago. Doppler cooling of dilute atomic gases is an extremely successful application of this concept. More recently, anti-Stokes cooling in multilevel systems has been explored, culminating in the optical refrigeration of solids. Collisional redistribution of radiation has been proposed as a different cooling mechanism for atomic two-level systems, although experimental investigations using moderate-density gases have not reached the cooling regime. Here we experimentally demonstrate laser cooling of an atomic gas based on collisional redistribution of radiation, using rubidium atoms in argon buffer gas at a pressure of 230 bar. The frequent collisions in the ultradense gas transiently shift a highly red-detuned laser beam (that is, one detuned to a much lower frequency) into resonance, whereas spontaneous decay occurs close to the unperturbed atomic resonance frequency. During each excitation cycle, kinetic energy of order k(B)T-that is, the thermal energy (k(B), Boltzmann's constant; T, temperature)-is extracted from the dense atomic sample. In a proof-of-principle experiment with a thermally non-isolated sample, we demonstrate relative cooling by 66 K. The cooled gas has a density more than ten orders of magnitude greater than the typical values used in Doppler-cooling experiments, and the cooling power reaches 87 mW. Future applications of the technique may include supercooling beyond the homogeneous nucleation temperature and optical chillers. PMID:19727195

  1. Gas hydrate cool storage system

    DOEpatents

    Ternes, M.P.; Kedl, R.J.

    1984-09-12

    The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

  2. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  3. Terrestrial cooling and solar variability

    NASA Technical Reports Server (NTRS)

    Agee, E. M.

    1982-01-01

    Observational evidence from surface temperature records is presented and discussed which suggests a significant cooling trend over the Northern Hemisphere from 1940 to the present. This cooling trend is associated with an increase of the latitudinal gradient of temperature and the lapse rate, as predicted by climate models with decreased solar input and feedback mechanisms. Evidence suggests that four of these 80- to 100-year cycles of global surface temperature fluctuation may have occurred, and in succession, from 1600 to the present. Interpretation of sunspot activity were used to infer a direct thermal response of terrestrial temperature to solar variability on the time scale of the Gleissberg cycle (90 years, an amplitude of the 11-year cycles). A physical link between the sunspot activity and the solar parameter is hypothesized. Observations of sensible heat flux by stationary planetary waves and transient eddies, as well as general circulation modeling results of these processes, were examined from the viewpoint of the hypothesis of cooling due to reduced insolation.

  4. Heavy Elements and Cool Stars

    NASA Astrophysics Data System (ADS)

    Wahlgren, Glenn M.; Carpenter, Kenneth G.; Norris, Ryan P.

    2009-02-01

    We report on progress in the analysis of high-resolution near-IR spectra of α Orionis (M2 Iab) and other cool, luminous stars. Using synthetic spectrum techniques, we search for atomic absorption lines in the stellar spectra and evaluate the available line parameter data for use in our abundance analyses. Our study concentrates on the post iron-group elements copper through zirconium as a means of investigating the slow neutron-capture process of nucleosynthesis in massive stars and the mechanisms that transport recently processed material up into the photospheric region. We discuss problems with the atomic data and model atmospheres that need to be addressed before theoretically derived elemental abundances from pre-supernova nucleosynthesis calculations can be tested by comparison with abundances determined from observations of cool, massive stars.

  5. Heavy Elements and Cool Stars

    NASA Technical Reports Server (NTRS)

    Wahlgren, Glenn M.; Carpenter, Kenneth G.; Norris, Ryan P.

    2008-01-01

    We report on progress in the analysis of high-resolution near-IR spectra of alpha Orionis (M2 Iab) and other cool, luminous stars. Using synthetic spectrum techniques, we search for atomic absorption lines in the stellar spectra and evaluate the available line parameter data for use in our abundance analyses. Our study concentrates on the post iron-group elements copper through zirconium as a means of investigating the slow neutron-capture process of nucleosynthesis in massive stars and the mechanisms that transport recently processed material up into the photospheric region. We discuss problems with the atomic data and model atmospheres that need to be addressed before theoretically derived elemental abundances from pre-supernova nucleosynthesis calculations can be tested by comparison with abundances determined from observations of cool, massive stars.

  6. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, Gregory W.; Kotsubo, Vincent Y.

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of .sup.3 He in a single phase .sup.3 He-.sup.4 He solution. The .sup.3 He in superfluid .sup.4 He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid .sup.3 He at an initial concentration in superfluid .sup.4 He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of .sup.4 He while restricting passage of .sup.3 He. The .sup.3 He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K.

  7. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, G.W.; Kotsubo, V.Y.

    1992-12-22

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of [sup 3]He in a single phase [sup 3]He-[sup 4]He solution. The [sup 3]He in superfluid [sup 4]He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid [sup 3]He at an initial concentration in superfluid [sup 4]He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of [sup 4]He while restricting passage of [sup 3]He. The [sup 3]He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K. 12 figs.

  8. Absorption-heat-pump system

    DOEpatents

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  9. Alternatives to compressor cooling in California climates

    SciTech Connect

    Feustel, H. ); de Almeida, A. . Dept. of Electrical Engineering); Blumstein, C. . Universitywide Energy Research Group)

    1991-01-01

    This review and discussion has been prepared for the California Institute for Energy Efficiency (CIEE) to examine research on alternatives to compressor cooling. The report focuses on strategies for eliminating compressors in California's transition climates -- moderately warm areas located between the cool coastal regions and the hot central regions. Many of these strategies could also help reduce compressor use in hotter climates. Compressor-driven cooling of residences in California's transition climate regions is an undesirable load for California's electric utilities because load factor is poor and usage is typically high during periods of system peak demand. We review a number of alternatives to compressors, including low-energy strategies: evaporative cooling, natural and induced ventilation, reflective coatings, shading with vegetation and improved glazing, thermal storage, and radiative cooling. Also included are two energy-intensive strategies: absorption cooling and desiccant cooling. Our literature survey leads us to conclude that many of these strategies, used either singly or in combination, are technically and economically feasible alternatives to compressor-driven cooling. 78 refs., 8 figs.

  10. Hydrogen Refrigerator Would Cool Below 10 K

    NASA Technical Reports Server (NTRS)

    Jones, J. A.

    1986-01-01

    Closed-cycle hydrogen refrigerator uses low-level heat energy to cool objects to temperature of 10 K. Refrigerator needs only fraction of energy of previous equipment with similar low-temperature capability. Unit compact and light in weight. With valves as only moving parts, reliable for many years. Refrigeration concept adapted to cooling superconducting magnets on magnetically levitated railcars, nuclear-particle accelerators, and variety of other cryogenic equipment.

  11. Stirling Air Conditioner for Compact Cooling

    SciTech Connect

    2010-09-01

    BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry to make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.

  12. Hybrid radiator cooling system

    DOEpatents

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  13. User manual for GEOCITY: a computer model for cost analysis of geothermal district-heating-and-cooling systems. Volume I. Main text

    SciTech Connect

    Huber, H.D.; Fassbender, L.L.; Bloomster, C.H.

    1982-09-01

    The purpose of this model is to calculate the costs of residential space heating, space cooling, and sanitary water heating or process heating (cooling) using geothermal energy from a hydrothermal reservoir. The model can calculate geothermal heating and cooling costs for residential developments, a multi-district city, or a point demand such as an industrial factory or commercial building. GEOCITY simulates the complete geothermal heating and cooling system, which consists of two principal parts: the reservoir and fluid transmission system and the distribution system. The reservoir and fluid transmission submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the reservoir and fluid transmission system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. Geothermal space heating is assumed to be provided by circulating hot water through radiators, convectors, fan-coil units, or other in-house heating systems. Geothermal process heating is provided by directly using the hot water or by circulating it through a process heat exchanger. Geothermal space or process cooling is simulated by circulating hot water through lithium bromide/water absorption chillers located at each building. Retrofit costs for both heating and cooling applications can be input by the user. The life-cycle cost of thermal energy from the reservoir and fluid transmission system to the distribution system and the life-cycle cost of heat (chill) to the end-users are calculated using discounted cash flow analysis.

  14. Permeability enhancement by shock cooling

    NASA Astrophysics Data System (ADS)

    Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean

    2015-04-01

    The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

  15. Analyzing Water's Optical Absorption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

  16. Elastocaloric cooling materials and systems

    NASA Astrophysics Data System (ADS)

    Takeuchi, Ichiro

    2015-03-01

    We are actively pursuing applications of thermoelastic (elastocaloric) cooling using shape memory alloys. Latent heat associated with martensitic transformation of shape memory alloys can be used to run cooling cycles with stress-inducing mechanical drives. The coefficient of performance of thermoelastic cooling materials can be as high as 11 with the directly measured DT of around 17 °C. Depending on the stress application mode, the number of cycles to fatigue can be as large as of the order of 105. Efforts to design and develop thermoelastic alloys with long fatigue life will be discussed. The current project at the University of Maryland is focused on development of building air-conditioners, and at Maryland Energy and Sensor Technologies, smaller scale commercial applications are being pursued. This work is carried out in collaboration with Jun Cui, Yiming Wu, Suxin Qian, Yunho Hwang, Jan Muehlbauer, and Reinhard Radermacher, and it is funded by the ARPA-E BEETIT program and the State of Maryland.

  17. Triple effect absorption chiller utilizing two refrigeration circuits

    DOEpatents

    DeVault, Robert C.

    1988-01-01

    A triple effect absorption method and apparatus having a high coefficient of performance. Two single effect absorption circuits are combined with heat exchange occurring between a condenser and absorber of a high temperature circuit, and a generator of a low temperature circuit. The evaporators of both the high and low temperature circuits provide cooling to an external heat load.

  18. Adiabatic cooling of antiprotons.

    PubMed

    Gabrielse, G; Kolthammer, W S; McConnell, R; Richerme, P; Kalra, R; Novitski, E; Grzonka, D; Oelert, W; Sefzick, T; Zielinski, M; Fitzakerley, D; George, M C; Hessels, E A; Storry, C H; Weel, M; Müllers, A; Walz, J

    2011-02-18

    Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3×10(6) p are cooled to 3.5 K-10(3) times more cold p and a 3 times lower p temperature than previously reported. A second cooling method cools p plasmas via the synchrotron radiation of embedded e(-) (with many fewer e(-) than p in preparation for adiabatic cooling. No p are lost during either process-a significant advantage for rare particles. PMID:21405511

  19. Adiabatic Cooling of Antiprotons

    SciTech Connect

    Gabrielse, G.; Kolthammer, W. S.; McConnell, R.; Richerme, P.; Kalra, R.; Novitski, E.; Oelert, W.; Grzonka, D.; Sefzick, T.; Zielinski, M.; Fitzakerley, D.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Muellers, A.; Walz, J.

    2011-02-18

    Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3x10{sup 6} p are cooled to 3.5 K--10{sup 3} times more cold p and a 3 times lower p temperature than previously reported. A second cooling method cools p plasmas via the synchrotron radiation of embedded e{sup -} (with many fewer e{sup -} than p) in preparation for adiabatic cooling. No p are lost during either process--a significant advantage for rare particles.

  20. Cooling, AGN Feedback and Star Formation in Cool-Core Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Bryan, Greg; Ruszkowski, Mateusz

    2015-01-01

    The feedback from active galactic nuclei (AGNs) is widely considered to be the major heating source in cool-core galaxy clusters to prevent a classical cooling flow. Numerical simulations with AGN feedback have successfully suppressed radiative cooling, but generally fail to reproduce the right amount of cold gas and the expected cyclical AGN activities. We perform adaptive mesh simulations including both momentum-driven AGN feedback and star formation to study the interplay between cooling, AGN heating and star formation over ~ 6.5 Gyr time in an isolated cool-core cluster. Cold clumps first cool out of the ICM due to the non-liner perturbation driven by the AGN jets. These cold clumps feed both star formation and the supermassive black hole (SMBH), triggering an AGN outburst which increases the entropy of the ICM and reduces its cooling rate. Within 1-2 Gyr, star formation completely consumes the cold gas, which leads to a brief shutoff of the AGN. The ICM quickly cools and develops multiphase gas again, followed by another cycle of star formation/AGN outburst. Within 6.5 Gyr, we observe three such cycles. The average star formation rate is ~40 solar mass/yr. The black hole accretion rate shows a large scatter, but the average correlates well with the star formation rate and is roughly one order of magnitude lower.

  1. Evaluation of thermal-storage concepts for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Hughes, P. J.; Morehouse, J. H.; Choi, M. K.; White, N. M.; Scholten, W. B.

    1981-10-01

    Various configuration concepts for utilizing thermal energy storage to improve the thermal and economic performance of solar cooling systems for buildings were analyzed. The storge concepts evaluated provide short-term thermal storge via the bulk containment of water or salt hydrates. The evaluations were made for both residential-size cooling systems (3-ton) and small commercial-size cooling systems (25-ton). The residential analysis considers energy requirements for space heating, space cooling and water heating, while the commercial building analysis is based only on energy requirements for space cooling. The commercial building analysis considered a total of 10 different thermal storage/solar systems, 5 each for absorption and Rankine chiller concepts. The residential analysis considered 4 thermal storage/solar systems, all utilizing an absorption chiller. The trade-offs considered include: cold-side versus hot-side storage, single vs multiple stage storage, and phase-change vs sensible heat storage.

  2. Liquid cooled garments

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Liquid cooled garments employed in several applications in which severe heat is encountered are discussed. In particular, the use of the garments to replace air line cooling units in a variety of industrial processing situations is discussed.

  3. Debuncher cooling performance

    SciTech Connect

    Derwent, P.F.; McGinnis, David; Pasquinelli, Ralph; Vander Meulen, David; Werkema, Steven; /Fermilab

    2005-11-01

    We present measurements of the Fermilab Debuncher momentum and transverse cooling systems. These systems use liquid helium cooled waveguide pickups and slotted waveguide kickers covering the frequency range 4-8 GHz.

  4. Debuncher Cooling Performance

    SciTech Connect

    Derwent, P. F.; McGinnis, David; Pasquinelli, Ralph; Vander Meulen, David; Werkema, Steven

    2006-03-20

    We present measurements of the Fermilab Debuncher momentum and transverse cooling systems. These systems use liquid helium cooled waveguide pickups and slotted waveguide kickers covering the frequency range 4-8 GHz.

  5. Liquid-Cooled Garment

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A liquid-cooled bra, offshoot of Apollo moon suit technology, aids the cancer-detection technique known as infrared thermography. Water flowing through tubes in the bra cools the skin surface to improve resolution of thermograph image.

  6. Radial turbine cooling

    NASA Astrophysics Data System (ADS)

    Roelke, Richard J.

    The technology of high temperature cooled radial turbines is reviewed. Aerodynamic performance considerations are described. Heat transfer and structural analysis are addressed, and in doing so the following topics are covered: cooling considerations, hot side convection, coolant side convection, and rotor mechanical analysis. Cooled rotor concepts and fabrication are described, and the following are covered in this context: internally cooled rotor, hot isostatic pressure bonded rotor, laminated rotor, split blade rotor, and the NASA radial turbine program.

  7. Radial turbine cooling

    NASA Technical Reports Server (NTRS)

    Roelke, Richard J.

    1992-01-01

    The technology of high temperature cooled radial turbines is reviewed. Aerodynamic performance considerations are described. Heat transfer and structural analysis are addressed, and in doing so the following topics are covered: cooling considerations, hot side convection, coolant side convection, and rotor mechanical analysis. Cooled rotor concepts and fabrication are described, and the following are covered in this context: internally cooled rotor, hot isostatic pressure bonded rotor, laminated rotor, split blade rotor, and the NASA radial turbine program.

  8. Data center cooling system

    DOEpatents

    Chainer, Timothy J; Dang, Hien P; Parida, Pritish R; Schultz, Mark D; Sharma, Arun

    2015-03-17

    A data center cooling system may include heat transfer equipment to cool a liquid coolant without vapor compression refrigeration, and the liquid coolant is used on a liquid cooled information technology equipment rack housed in the data center. The system may also include a controller-apparatus to regulate the liquid coolant flow to the liquid cooled information technology equipment rack through a range of liquid coolant flow values based upon information technology equipment temperature thresholds.

  9. RE cycle: A system for good off-design performance

    SciTech Connect

    Facchini, B.; Sguanci, S.

    1994-12-31

    The paper presents a modified Joule cycle with intermediate regeneration along the expansion phase called RE (Regenerative Expansion turbine). The cycle offers efficiency increments with respect to simple Joule cycles and to the conventional regenerative cycle, even at high compression ratios. In particular, the features of off-design performance in a twin-shaft cycle arrangement are very interesting, because higher efficiency is obtained at partial loads. The blade cooling effects are also investigated and show a strongly negative influence on the cycle`s performance, therefore, the introduction of a high efficiency blade cooling system would be very important to the RE cycle.

  10. Controlled Rate Cooling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlled-rate cooling is one of several techniques available for the long-term storage of plants in liquid nitrogen. In this technique samples are slowly cooled to an intermediate temperature and then plunged in liquid nitrogen. Controlled rate cooling is based on osmotic regulation of cell conte...

  11. Stochastic cooling in RHIC

    SciTech Connect

    Brennan,J.M.; Blaskiewicz, M. M.; Severino, F.

    2009-05-04

    After the success of longitudinal stochastic cooling of bunched heavy ion beam in RHIC, transverse stochastic cooling in the vertical plane of Yellow ring was installed and is being commissioned with proton beam. This report presents the status of the effort and gives an estimate, based on simulation, of the RHIC luminosity with stochastic cooling in all planes.

  12. Cooling apparatus for water-cooled engines

    SciTech Connect

    Fujikawa, T.; Tamba, S.

    1986-05-20

    A cooling apparatus is described for a water-cooled internal combustion engine including a shaft that rotates when the engine is running, the apparatus comprising a centrifugal fan adapted to be connected to and rotated by the shaft, the fan having an intake air port and a discharge air opening, a rotary screen adapted to be operatively connected to and rotated by the shaft, the screen being disposed in the intake air port, a cooling radiator, a spiral-shaped duct connecting the radiator with the discharge air opening, and separating means on the duct, the separating means comprising an opening formed in the outer wall of the duct.

  13. Optical cooling of Nd-doped solids

    NASA Astrophysics Data System (ADS)

    Garcia-Adeva, Angel J.; Balda, Rolindes; Al Saleh, Mohammed; Garcia-Revilla, Sara; Sola, Daniel; Fernández, Joaquín

    2012-03-01

    In this work we present a comprehensive review of recent work carried out by our group in the field of optical refrigeration of Nd-doped solids. Several infrared thermography measurements in Nd-doped KPb2Cl5 crystals and micro-powders both above and below the barycentre of the 4F3/2 are presented. These include some of our most recent ones obtained by employing a novel technique that allows one to perform differential temperature measurements. The role of both the direct anti-Stokes absorption processes and those assisted by either excited state absorption or energy transfer upconversion in the cooling process is discussed.

  14. Cooling water distribution system

    DOEpatents

    Orr, Richard

    1994-01-01

    A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

  15. Heating and cooling system

    SciTech Connect

    Imig, L.A.; Gardner, M.R.

    1982-08-01

    A heating and cooling apparatus capable of cyclic heating and cooling of a test specimen undergoing fatigue testing is discussed. Cryogenic fluid is passed through a block clamped to the speciment to cool the block and the specimen. Heating cartridges penetrate the block to heat the block and the specimen to very hot temperaures. Control apparatus is provided to alternatively activate the cooling and heating modes to effect cyclic heating and cooling between very hot and very cold temperatures. The block is constructed of minimal mass to facilitate the rapid temperature changes. Official Gazette of the U.S. Patent and Trademark Office.

  16. Prospects of laser cooling in atomic thallium

    SciTech Connect

    Fan, Isaac; Chen, Tzu-Ling; Liu, Yu-Sheng; Lien, Yu-Hung; Liu, Yi-Wei; Shy, Jow-Tsong

    2011-10-15

    One of the most precisely determined upper limits for the electron electric dipole moment (EDM) is set by the thallium (Tl) atomic beam experiment. One way to enhance the sensitivity of the atomic beam setup is to laser cool the Tl atoms to reduce the EDM-like phase caused by the Exv effect. In this report, a cooling scheme based on the 6P{sub 3/2}(F=2){r_reversible}6D{sub 5/2}(F{sup '}=3) transition in Tl is proposed. The absolute frequency measurement of this nearly closed-cycle transition was performed in an atomic beam apparatus. Two Ti:sapphire lasers were frequency-doubled using enhancement cavities in X-type configurations to provide the needed 377- and 352-nm light sources for the optical pumping and cooling transitions, respectively. The absolute frequency of this cooling transition is determined to be 851 634 646(56) MHz.

  17. Integrated turbine-compressor provides air flow for cooling

    NASA Technical Reports Server (NTRS)

    Ferri, A.

    1970-01-01

    Modified supersonic turbine cycle provides cooling air to surrounding structures. Simplified mechanical design assures correct balance of air flow, allows direct issue of cool air to the structure, and assists in matching turbine work output to work input required by the compressor.

  18. Keeping cool while planning a major cooling system modification for a large base-loaded power plant

    SciTech Connect

    Mallory, J.; Randels, R.; Penrose, J.; Ludovisi, D.

    2012-07-01

    This paper addresses vital considerations which need to be addressed to help ensure that the wisest approach is used for evaluating or modifying existing open or closed cycle cooling systems. (authors)

  19. The photochemical cycle of bacteriorhodopsin

    NASA Technical Reports Server (NTRS)

    Lozier, R. H.; Niederberger, W.

    1977-01-01

    The reaction cycle of bacteriorhodopsin in the purple membrane isolated from Halobacterium halobium has been studied by optical absorption spectroscopy using low-temperature and flash kinetic techniques. After absorption of light, bacteriorhodopsin passes through at least five distinct intermediates. The temperature and pH dependence of the absorbance changes suggests that branch points and/or reversible steps exist in this cycle. Flash spectroscopy in the presence of a pH-indicating dye shows that the transient release of a proton accompanies the photoreaction cycle. The proton release occurs from the exterior and the uptake is on the cytoplasmic side of the membrane, as required by the function of bacteriorhodopsin as a light-driven proton pump. Proton translocating steps connecting release and uptake are indicated by deuterium isotope effects on the kinetics of the cycle. The rapid decay of a light-induced linear dichroism shows that a chromophore orientation change occurs during the reaction cycle.

  20. Evolution of cool-roof standards in the United States

    SciTech Connect

    Akbari, Hashem; Akbari, Hashem; Levinson, Ronnen

    2008-07-11

    Roofs that have high solar reflectance and high thermal emittance stay cool in the sun. A roof with lower thermal emittance but exceptionally high solar reflectance can also stay cool in the sun. Substituting a cool roof for a noncool roof decreases cooling-electricity use, cooling-power demand, and cooling-equipment capacity requirements, while slightly increasing heating-energy consumption. Cool roofs can also lower citywide ambient air temperature in summer, slowing ozone formation and increasing human comfort. Provisions for cool roofs in energy-efficiency standards can promote the building- and climate-appropriate use of cool roofing technologies. Cool-roof requirements are designed to reduce building energy use, while energy-neutral cool-roof credits permit the use of less energy-efficient components (e.g., larger windows) in a building that has energy-saving cool roofs. Both types of measures can reduce the life-cycle cost of a building (initial cost plus lifetime energy cost). Since 1999, several widely used building energy-efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool-roof credits or requirements. This paper reviews the technical development of cool-roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discusses the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool-roof provisions can be used as models to address cool roofs in building energy-efficiency standards worldwide.

  1. Raman cooling in silicon photonic crystals

    NASA Astrophysics Data System (ADS)

    Chen, Yin-Chung; Bahl, Gaurav

    2016-03-01

    Laser cooling of solids can be achieved through various photon up-conversion processes including anti-Stokes photoluminescence and anti-Stokes light scattering. While it has been shown that cooling using photoluminescence-based methods can achieve efficiency comparable to that of thermoelectric cooling, the reliance on specific transitions of the rare-earth dopants limits material choice. Light scattering, on the other hand, occurs in all materials, and has the potential to enable cooling in most materials. We show that by engineering the photonic density of states of a material, one can suppress the Stokes process, and enhance the anti-Stokes radiation. We employ the well-known diamond-structured photonic crystal patterned in crystalline silicon to demonstrate theoretically that when operating within a high transparency regime, the net energy removal rate from phonon annihilation can overcome the optical absorption. The engineered photonic density of states can thus enable simultaneous cooling of all Raman-active phonon modes and the net cooling of the solid.

  2. Cooling, AGN Feedback, and Star Formation in Simulated Cool-core Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Bryan, Greg L.; Ruszkowski, Mateusz; Voit, G. Mark; O'Shea, Brian W.; Donahue, Megan

    2015-10-01

    Numerical simulations of active galactic nuclei (AGNs) feedback in cool-core galaxy clusters have successfully avoided classical cooling flows, but often produce too much cold gas. We perform adaptive mesh simulations that include momentum-driven AGN feedback, self-gravity, star formation, and stellar feedback, focusing on the interplay between cooling, AGN heating, and star formation in an isolated cool-core cluster. Cold clumps triggered by AGN jets and turbulence form filamentary structures tens of kpc long. This cold gas feeds both star formation and the supermassive black hole (SMBH), triggering an AGN outburst that increases the entropy of the intracluster medium (ICM) and reduces its cooling rate. Within 1-2 Gyr, star formation completely consumes the cold gas, leading to a brief shutoff of the AGN. The ICM quickly cools and redevelops multiphase gas, followed by another cycle of star formation/AGN outburst. Within 6.5 Gyr, we observe three such cycles. There is good agreement between our simulated cluster and the observations of cool-core clusters. ICM cooling is dynamically balanced by AGN heating, and a cool-core appearance is preserved. The minimum cooling time to free-fall time ratio typically varies between a few and ≳ 20. The star formation rate (SFR) covers a wide range, from 0 to a few hundred {M}⊙ {{yr}}-1, with an average of ˜ 40 {M}⊙ {{yr}}-1. The instantaneous SMBH accretion rate shows large variations on short timescales, but the average value correlates well with the SFR. Simulations without stellar feedback or self-gravity produce qualitatively similar results, but a lower SMBH feedback efficiency (0.1% compared to 1%) results in too many stars.

  3. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    SciTech Connect

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  4. Hole Cooling Is Much Faster than Electron Cooling in PbSe Quantum Dots.

    PubMed

    Spoor, Frank C M; Kunneman, Lucas T; Evers, Wiel H; Renaud, Nicolas; Grozema, Ferdinand C; Houtepen, Arjan J; Siebbeles, Laurens D A

    2016-01-26

    In semiconductor quantum dots (QDs), charge carrier cooling is in direct competition with processes such as carrier multiplication or hot charge extraction that may improve the light conversion efficiency of photovoltaic devices. Understanding charge carrier cooling is therefore of great interest. We investigate high-energy optical transitions in PbSe QDs using hyperspectral transient absorption spectroscopy. We observe bleaching of optical transitions involving higher valence and conduction bands upon band edge excitation. The kinetics of rise of the bleach of these transitions after a pump laser pulse allow us to monitor, for the first time, cooling of hot electrons and hot holes separately. Our results show that holes cool significantly faster than electrons in PbSe QDs. This is in contrast to the common assumption that electrons and holes behave similarly in Pb chalcogenide QDs and has important implications for the utilization of hot charge carriers in photovoltaic devices. PMID:26654878

  5. Stochastic cooling in RHIC

    SciTech Connect

    Brennan J. M.; Blaskiewicz, M.; Mernick, K.

    2012-05-20

    The full 6-dimensional [x,x'; y,y'; z,z'] stochastic cooling system for RHIC was completed and operational for the FY12 Uranium-Uranium collider run. Cooling enhances the integrated luminosity of the Uranium collisions by a factor of 5, primarily by reducing the transverse emittances but also by cooling in the longitudinal plane to preserve the bunch length. The components have been deployed incrementally over the past several runs, beginning with longitudinal cooling, then cooling in the vertical planes but multiplexed between the Yellow and Blue rings, next cooling both rings simultaneously in vertical (the horizontal plane was cooled by betatron coupling), and now simultaneous horizontal cooling has been commissioned. The system operated between 5 and 9 GHz and with 3 x 10{sup 8} Uranium ions per bunch and produces a cooling half-time of approximately 20 minutes. The ultimate emittance is determined by the balance between cooling and emittance growth from Intra-Beam Scattering. Specific details of the apparatus and mathematical techniques for calculating its performance have been published elsewhere. Here we report on: the method of operation, results with beam, and comparison of results to simulations.

  6. Potential of solar cooling systems for peak demand reduction

    SciTech Connect

    Pesaran, A A; Neymark, J

    1994-11-01

    We investigated the technical feasibility of solar cooling for peak demand reduction using a building energy simulation program (DOE2.1D). The system studied was an absorption cooling system with a thermal coefficient of performance of 0.8 driven by a solar collector system with an efficiency of 50% with no thermal storage. The analysis for three different climates showed that, on the day with peak cooling load, about 17% of the peak load could be met satisfactorily with the solar-assisted cooling system without any thermal storage. A performance availability analysis indicated that the solar cooling system should be designed for lower amounts of available solar resources that coincide with the hours during which peak demand reduction is required. The analysis indicated that in dry climates, direct-normal concentrating collectors work well for solar cooling; however, in humid climates, collectors that absorb diffuse radiation work better.

  7. Direct-Circulation Stirling-Cycle Refrigerator

    NASA Technical Reports Server (NTRS)

    Ellison, Woody; Kohuth, Randall, Sr.

    1995-01-01

    In proposed cryogenic system, cold working fluid (helium) circulated directly from Stirling-cycle refrigerator machinery through loop of tubing to provide 15 W of cooling power at temperature of 80 K to scientific instruments or other devices located at some distance from machinery. (Separation of cooled devices from machinery may be dictated by engineering requirements including, need to isolate cooled devices from vibrations of machinery.) Advantages include less complexity, smaller size, lighter weight, and lower power consumption.

  8. Fragile cycles

    NASA Astrophysics Data System (ADS)

    Bonatti, Ch.; Díaz, L. J.

    We study diffeomorphisms f with heterodimensional cycles, that is, heteroclinic cycles associated to saddles p and q with different indices. Such a cycle is called fragile if there is no diffeomorphism close to f with a robust cycle associated to hyperbolic sets containing the continuations of p and q. We construct a codimension one submanifold of Diff(S×S) that consists of diffeomorphisms with fragile heterodimensional cycles. Our construction holds for any manifold of dimension ⩾4.

  9. NASA Microclimate Cooling Challenges

    NASA Technical Reports Server (NTRS)

    Trevino, Luis A.

    2004-01-01

    The purpose of this outline form presentation is to present NASA's challenges in microclimate cooling as related to the spacesuit. An overview of spacesuit flight-rated personal cooling systems is presented, which includes a brief history of cooling systems from Gemini through Space Station missions. The roles of the liquid cooling garment, thermal environment extremes, the sublimator, multi-layer insulation, and helmet visor UV and solar coatings are reviewed. A second section is presented on advanced personal cooling systems studies, which include heat acquisition studies on cooling garments, heat rejection studies on water boiler & radiators, thermal storage studies, and insulation studies. Past and present research and development and challenges are summarized for the advanced studies.

  10. Enhanced squeezing by absorption

    NASA Astrophysics Data System (ADS)

    Grünwald, P.; Vogel, W.

    2016-04-01

    Absorption is usually expected to be detrimental to quantum coherence effects. However, there have been few studies into the situation for complex absorption spectra. We consider the resonance fluorescence of excitons in a semiconductor quantum well. The creation of excitons requires absorption of the incoming pump-laser light. Thus, the absorption spectrum of the medium acts as a spectral filter for the emitted light. Surprisingly, absorption can even improve quantum effects, as is demonstrated for the squeezing of the resonance fluorescence of the quantum-well system. This effect can be explained by an improved phase matching due to absorption.

  11. Solar heating and cooling

    NASA Technical Reports Server (NTRS)

    Bartera, R. E.

    1978-01-01

    To emphasize energy conservation and low cost energy, the systems of solar heating and cooling are analyzed and compared with fossil fuel systems. The application of solar heating and cooling systems for industrial and domestic use are discussed. Topics of discussion include: solar collectors; space heating; pools and spas; domestic hot water; industrial heat less than 200 F; space cooling; industrial steam; and initial systems cost. A question and answer period is generated which closes out the discussion.

  12. High energy electron cooling

    SciTech Connect

    Parkhomchuk, V.

    1997-09-01

    High energy electron cooling requires a very cold electron beam. The questions of using electron cooling with and without a magnetic field are presented for discussion at this workshop. The electron cooling method was suggested by G. Budker in the middle sixties. The original idea of the electron cooling was published in 1966. The design activities for the NAP-M project was started in November 1971 and the first run using a proton beam occurred in September 1973. The first experiment with both electron and proton beams was started in May 1974. In this experiment good result was achieved very close to theoretical prediction for a usual two component plasma heat exchange.

  13. Hydrogen film cooling investigation

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Ewen, R. L.

    1973-01-01

    Effects of flow turning, flow acceleration, and supersonic flow on film cooling were determined experimentally and correlated in terms of an entrainment film cooling model. Experiments were conducted using thin walled metal test sections, hot nitrogen mainstream gas, and ambient hydrogen or nitrogen as film coolants. The entrainment film cooling model relates film cooling effectiveness to the amount of mainstream gases entrained with the film coolant in a mixing layer. The experimental apparatus and the analytical model used are described in detail and correlations for the entrainment fraction and film coolant-to-wall heat transfer coefficient are presented.

  14. Passive containment cooling system

    DOEpatents

    Conway, Lawrence E.; Stewart, William A.

    1991-01-01

    A containment cooling system utilizes a naturally induced air flow and a gravity flow of water over the containment shell which encloses a reactor core to cool reactor core decay heat in two stages. When core decay heat is greatest, the water and air flow combine to provide adequate evaporative cooling as heat from within the containment is transferred to the water flowing over the same. The water is heated by heat transfer and then evaporated and removed by the air flow. After an initial period of about three to four days when core decay heat is greatest, air flow alone is sufficient to cool the containment.

  15. Malone cycle refrigerator development

    SciTech Connect

    Shimko, M.A.; Crowley, C.J.

    1999-07-01

    This paper describes the progress made in demonstrating a Malone Cycle Refrigerator/Freezer. The Malone cycle is similar to the Stirling cycle but uses a supercritical fluid in place of real gas. In the approach, solid-metal diaphragms are used to seal and sweep the working volumes against the high working fluid pressures required in Malone cycle machines. This feature eliminates the friction and leakage that accounted for nearly half the losses in the best piston-defined Malone cycle machines built to date. The authors successfully built a Malone cycle refrigerator that: (1) used CO{sub 2} as the working fluid, (2) operated at pressures up to 19.3 Mpa (2,800 psi), (3) achieved a cold end metal temperatures of {minus}29 C ({minus}20 F), and (4) produced over 400 Watts of cooling at near ambient temperatures. The critical diaphragm components operated flawlessly throughout characterization and performance testing, supporting the conclusion of high reliability based on analysis of fatigue date and actual strain measurements.

  16. D-xylose absorption

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  17. Solar heating and cooling buildings

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Sunshine is available in differing amounts everywhere in the world and the easiest method of capturing it is by absorption in the form of thermal energy (heat). Therefore, it is logical to utilize it directly in the heating and cooling of buildings and avoid losses that would occur by conversion to some other form. It may be emphasized that of the total energy consumed annually in the U.S., about 25% is used for heating and cooling in buildings. It is generally agreed that of all the possible widespread uses of solar energy, this application has the highest probability of success in the near term. Although there are significant uncertainties associated with some technological and economic aspects, they do not loom as large as those associated with other potentially significant applications, such as electrical power generation. It may, however, be noted that solar electrical power generation at the building site, or at a centralized station is an excellent long term prospect. Approximately 25 experimental solar heated structures have been built in various parts of the world.

  18. Stacking with stochastic cooling

    NASA Astrophysics Data System (ADS)

    Caspers, Fritz; Möhl, Dieter

    2004-10-01

    Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some considerations to the 'azimuthal' schemes.

  19. Low cost solar energy collection for cooling applications

    NASA Astrophysics Data System (ADS)

    Wilhelm, W. G.

    1981-06-01

    Solar energy collector designs utilizing thin-film polymeric materials in the absorber and glazing are investigated. The main objective is dramatic cost reduction consistent with acceptable performance and life. These collectors now appear capable of high temperature applications including desiccant and absorption cooling (1500 to 2000 F). The performance and economics of the thin-film collector are compared with those of conventional flat-plate designs in cooling applications.

  20. Proposal for laser cooling of rare-earth ions

    NASA Astrophysics Data System (ADS)

    Lepers, Maxence; Hong, Ye; Wyart, Jean-François; Dulieu, Olivier

    2016-01-01

    The efficiency of laser cooling relies on the existence of an almost closed optical-transition cycle in the energy spectrum of the considered species. In this respect, rare-earth elements exhibit many transitions which are likely to induce noticeable leaks from the cooling cycle. In this work, to determine whether laser cooling of singly ionized erbium Er+ is feasible, we have performed accurate electronic-structure calculations of energies and spontaneous-emission Einstein coefficients of Er+, using a combination of ab initio and least-squares-fitting techniques. We identify five weak closed transitions suitable for laser cooling, the broadest of which is in the kilohertz range. For the strongest transitions, by simulating the cascade dynamics of spontaneous emission, we show that repumping is necessary, and we discuss possible repumping schemes. We expect our detailed study on Er+ to give good insight into the laser cooling of neighboring ions such as Dy+.

  1. Liquid metal cooled nuclear reactors with passive cooling system

    DOEpatents

    Hunsbedt, Anstein; Fanning, Alan W.

    1991-01-01

    A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of cooling medium flow circuits which cooperate to remove and carry heat away from the fuel core upon loss of the normal cooling flow circuit to areas external thereto.

  2. Passive Reactor Cooling Using Capillary Porous Wick

    SciTech Connect

    Miller, Christopher G.; Lin, Thomas F.

    2006-07-01

    Long-term reliability of actively pumped cooling systems is a concern in space-based nuclear reactors. Capillary-driven passive cooling systems are being considered as an alternative to gravity-driven systems. The high surface tension of liquid lithium makes it attractive as the coolant in a capillary-driven cooling system. A system has been conceived in which the fuel rod of a reactor is surrounded by a concentric wick through which liquid lithium flows to provide cooling under normal and emergency operating conditions. Unheated wicking experiments at three pressures using four layered screen mesh wicks of different porosities and three relatively high surface tension fluids have been conducted to gain insight into capillary phenomena for such a capillary cooling system. All fluids tested demonstrated wicking ability in each of the wick structures for all pressures, and wicking ability for each fluid increased with decreasing wick pore size. An externally heated wicking experiment with liquid lithium as the wicking fluid was also conducted. In addition to wicking experiments, a heater rod is under development to simulate the fuel rod of a space based nuclear reactor by providing a heat flux of up to 110 kW/m{sup 2}. Testing of this heater rod has shown its ability to undergo repeated cycling from below 533 K to over 1255 K without failure. This heater rod will be integrated into lithium wicking experiments to provide more realistic simulation of the proposed capillary-driven space nuclear reactor cooling system. (authors)

  3. DOAS, Radiant Cooling Revisited

    SciTech Connect

    Hastbacka, Mildred; Dieckmann, John; Bouza, Antonio

    2012-12-01

    The article discusses dedicated outdoor air systems (DOAS) and radiant cooling technologies. Both of these topics were covered in previous ASHRAE Journal columns. This article reviews the technologies and their increasing acceptance. The two steps that ASHRAE is taking to disseminate DOAS information to the design community, available energy savings and the market potential of radiant cooling systems are addressed as well.

  4. Measure Guideline: Ventilation Cooling

    SciTech Connect

    Springer, D.; Dakin, B.; German, A.

    2012-04-01

    The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  5. Why Cool Roofs?

    ScienceCinema

    Chu, Steven

    2013-05-29

    By installing a cool roof at DOE, the federal government and Secretary Chu are helping to educate families and businesses about the important energy and cost savings that can come with this simple, low-cost technology. Cool roofs have the potential to quickly and dramatically reduce global carbon emissions while saving money every month on consumers' electrical bills.

  6. Cool Earth Solar

    ScienceCinema

    Lamkin, Rob; McIlroy, Andy; Swalwell, Eric; Rajan, Kish

    2014-02-26

    In a public-private partnership that takes full advantage of the Livermore Valley Open Campus (LVOC) for the first time, Sandia National Laboratories and Cool Earth Solar have signed an agreement that could make solar energy more affordable and accessible. In this piece, representatives from Sandia, Cool Earth Solar, and leaders in California government all discuss the unique partnership and its expected impact.

  7. Data center cooling method

    DOEpatents

    Chainer, Timothy J.; Dang, Hien P.; Parida, Pritish R.; Schultz, Mark D.; Sharma, Arun

    2015-08-11

    A method aspect for removing heat from a data center may use liquid coolant cooled without vapor compression refrigeration on a liquid cooled information technology equipment rack. The method may also include regulating liquid coolant flow to the data center through a range of liquid coolant flow values with a controller-apparatus based upon information technology equipment temperature threshold of the data center.

  8. Coherent electron cooling

    SciTech Connect

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  9. District cooling in Scandinavia

    SciTech Connect

    Andersson, B.

    1996-11-01

    This paper will present the status of the development of district cooling systems in Scandinavia over the last 5 years. It will describe the technologies used in the systems that have been constructed as well as the options considered in different locations. It will identify the drivers for the development of the cooling business to-date, and what future drivers for a continuing development of district cooling in Sweden. To-date, approximately 25 different cities of varying sizes have completed feasibility studies to determine if district cooling is an attractive option. In a survey, that was conducted by the Swedish District Heating Association, some 25 cities expected to have district cooling systems in place by the year 2000. In Sweden, district heating systems with hot water is very common. In many cases, it is simply an addition to the current service for the district heating company to also supply district cooling to the building owners. A parallel from this can be drawn to North America where district cooling systems now are developing rapidly. I am convinced that in these cities a district heating service will be added as a natural expansion of the district cooling company`s service.

  10. Liquid Cooled Garments

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Astronauts working on the surface of the moon had to wear liquid-cooled garments under their space suits as protection from lunar temperatures which sometimes reach 250 degrees Fahrenheit. In community service projects conducted by NASA's Ames Research Center, the technology developed for astronaut needs has been adapted to portable cooling systems which will permit two youngsters to lead more normal lives.

  11. Why Cool Roofs?

    SciTech Connect

    Chu, Steven

    2010-01-01

    By installing a cool roof at DOE, the federal government and Secretary Chu are helping to educate families and businesses about the important energy and cost savings that can come with this simple, low-cost technology. Cool roofs have the potential to quickly and dramatically reduce global carbon emissions while saving money every month on consumers' electrical bills.

  12. S'COOL Science

    ERIC Educational Resources Information Center

    Bryson, Linda

    2004-01-01

    This article describes one fifth grade's participation in in NASA's S'COOL (Students' Cloud Observations On-Line) Project, making cloud observations, reporting them online, exploring weather concepts, and gleaning some of the things involved in authentic scientific research. S?COOL is part of a real scientific study of the effect of clouds on…

  13. First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

    2009-01-01

    Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong vs band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

  14. First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

    2009-01-01

    Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong n8 band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

  15. In Hot Water: A Cooling Tower Case Study

    ERIC Educational Resources Information Center

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

    2005-01-01

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

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

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  17. Menstrual Cycle

    MedlinePlus

    ... Pregnancy This information in Spanish ( en español ) The menstrual cycle Day 1 starts with the first day of ... drop around Day 25 . This signals the next menstrual cycle to begin. The egg will break apart and ...

  18. Turbine blade cooling

    DOEpatents

    Staub, Fred Wolf; Willett, Fred Thomas

    1999-07-20

    A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number.

  19. Turbine blade cooling

    DOEpatents

    Staub, Fred Wolf; Willett, Fred Thomas

    2000-01-01

    A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number.

  20. Hydronic rooftop cooling systems

    DOEpatents

    Bourne, Richard C.; Lee, Brian Eric; Berman, Mark J.

    2008-01-29

    A roof top cooling unit has an evaporative cooling section that includes at least one evaporative module that pre-cools ventilation air and water; a condenser; a water reservoir and pump that captures and re-circulates water within the evaporative modules; a fan that exhausts air from the building and the evaporative modules and systems that refill and drain the water reservoir. The cooling unit also has a refrigerant section that includes a compressor, an expansion device, evaporator and condenser heat exchangers, and connecting refrigerant piping. Supply air components include a blower, an air filter, a cooling and/or heating coil to condition air for supply to the building, and optional dampers that, in designs that supply less than 100% outdoor air to the building, control the mixture of return and ventilation air.

  1. Water cooled steam jet

    DOEpatents

    Wagner, Jr., Edward P.

    1999-01-01

    A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed therebetween. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock.

  2. Turbine blade cooling

    SciTech Connect

    Staub, F.W.; Willett, F.T.

    1999-07-20

    A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number. 13 figs.

  3. Water cooled steam jet

    DOEpatents

    Wagner, E.P. Jr.

    1999-01-12

    A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed there between. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock. 2 figs.

  4. Multistage quantum absorption heat pumps

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N -2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

  5. Multistage quantum absorption heat pumps.

    PubMed

    Correa, Luis A

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration. PMID:24827213

  6. Quantum-enhanced absorption refrigerators

    PubMed Central

    Correa, Luis A.; Palao, José P.; Alonso, Daniel; Adesso, Gerardo

    2014-01-01

    Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators. PMID:24492860

  7. Transient simulation of absorption machines

    NASA Astrophysics Data System (ADS)

    Anand, D. K.; Allen, R. W.; Kumar, B.

    A model for a water-cooled Lithium-Bromide/water absorption chiller is presented. Its transient response both during the start-up phase and during the shut-off period is predicted. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steady-state value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation.

  8. Quantum-enhanced absorption refrigerators

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.; Palao, José P.; Alonso, Daniel; Adesso, Gerardo

    2014-02-01

    Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators.

  9. Quantum-enhanced absorption refrigerators.

    PubMed

    Correa, Luis A; Palao, José P; Alonso, Daniel; Adesso, Gerardo

    2014-01-01

    Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators. PMID:24492860

  10. Solar space heating and cooling by selective use of the components of a desiccant cooling system

    NASA Astrophysics Data System (ADS)

    Abbud, Ihsan Aladdin

    The economic advantages of by-passing various components of a desiccant cooling system under conditions not requiring their use are estimated by evaluating the annual costs of heating and cooling a commercial building in three representative U.S. cities. Life-cycle costs of systems employing solar heat for space heating and desiccant regeneration are compared with those using electric heat. The costs of purchasing and operating heating and desiccant cooling systems, with and without solar heat supply, are compared with those employing conventional heating and vapor compression cooling. The conditions under which commercial buildings can be cooled with desiccant systems at costs competitive with conventional systems are identified. A commercially available vapor compression air conditioner is used as a standard of comparison for energy consumption and room comfort. Heating and cooling requirements of the building are determined by use of the BLAST computer model in a simulation of long term system operation. Performance of the desiccant cooling system and life cycle savings obtained by its use are determined by simulation employing the TRNSYS computer model. TRNSYS compatible subroutines are developed to simulate operation of the desiccant equipment, the building, and the controllers that operate and monitor the system components. The results are presented in tabular and graphical form. This study shows that in the widely different climates represented in Los Angeles, New York, and Miami, by-passing various components in the desiccant cooling system when they are not needed is economically advantageous. Operation cost of the complete system decreased by 47.3% in Los Angeles, by 30.9% in New York City, and by 23.9% in Miami by not operating the desiccant wheel and other elements. The ventilation desiccant cooling system has major economic advantage over conventional systems under conditions of moderate humidity, as in Los Angeles and New York City. In Miami, however

  11. Advantages and disadvantages of using absorption chillers to lower utility bills

    SciTech Connect

    Kistler, P.

    1997-04-01

    Absorption chillers have a proven history of providing low-cost reliable cooling and should continue to do so in the future. Absorption chiller systems can provide significant energy savings for a particular application. To maximize savings, the various system arrangements should be evaluated; for example, single effect versus double effect, chiller versus chiller/heater, straight absorption chiller or the electric/absorption hybrid.

  12. Nanofibrous membrane-based absorption refrigeration system

    SciTech Connect

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  13. Grey-molasses cooling of an optically trapped Fermi gas

    NASA Astrophysics Data System (ADS)

    Day, Ryan; Jervis, Dylan; Edge, Graham; Anderson, Rhys; Trotzky, Stefan; Thywissen, Joseph

    2014-05-01

    Robust sub-Doppler cooling has recently been demonstrated at the D1 (nS1/2 to nP1/2) transition of potassium and lithium, atoms that are challenging to cool on the D2 cycling transition. Two mechanisms are at work: first, Sisyphus cooling in the standing-wave dipole potential, at least partially due to polarization gradients; second, velocity-selective coherent population trapping (VSCPT) in a superposition of the two hyperfine ground states. We extend this technique to the cooling of dense clouds in optical traps. Since the VSCPT dark state relies only on ground-state coherences, it is insensitive to optical shifts from far-detuned optical traps. We also observe that the molasses has sufficient cooling power to withstand light scattering on the 4S-5P transition. Together these observations indicate that D1 cooling is a promising approach to fluorescent imaging of single fermions in an optical lattice.

  14. MEIC electron cooling program

    SciTech Connect

    Derbenev, Yaroslav S.; Zhang, Yuhong

    2014-12-01

    Cooling of proton and ion beams is essential for achieving high luminosities (up to above 1034 cm-2s-1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); the other is a high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D.

  15. MEIC electron cooling program

    DOE PAGESBeta

    Derbenev, Yaroslav S.; Zhang, Yuhong

    2014-12-01

    Cooling of proton and ion beams is essential for achieving high luminosities (up to above 1034 cm-2s-1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); the other is amore » high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D.« less

  16. [Scalp cooling for chemotherapy-induced alopecia].

    PubMed

    Komen, Marion M C; Smorenburg, Carolien H; van den Hurk, Corina J G; Nortier, J W R Hans

    2011-01-01

    Alopecia is a very common side effect of cytostatic therapy and is considered one of the most emotionally distressing effects. To prevent alopecia scalp cooling is currently used in some indications in medical oncology in 59 hospitals in the Netherlands. The success of scalp cooling depends on various factors such as type of chemotherapy, dose, infusion time, number of treatment cycles and combinations of drugs. In general, scalp cooling is well tolerated. The reported side-effects are headache, coldness, dizziness and sometimes claustrophobia. An increase in the risk of scalp metastases has not been demonstrated. Proceeding from the South Netherlands Comprehensive Cancer Centre a national working group is put together in order to draw up a national guideline for chemotherapy-induced alopecia. PMID:22085565

  17. Transient simulation of absorption machines

    SciTech Connect

    Anand, D.K.; Allen, R.W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steadystate value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  18. Transient simulation of absorption machines

    NASA Astrophysics Data System (ADS)

    Anand, D. K.; Allen, R. W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steady-state value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  19. Theoretical model for Sub-Doppler Cooling with EIT System

    NASA Astrophysics Data System (ADS)

    He, Peiru; Tengdin, Phoebe; Anderson, Dana; Rey, Ana Maria; Holland, Murray

    2016-05-01

    We propose a of sub-Doppler cooling mechanism that takes advantage of the unique spectral features and extreme dispersion generated by the so-called Electromagnetically Induced Transparency (EIT) effect, a destructive quantum interference phenomenon experienced by atoms with Lambda-shaped energy levels when illuminated by two light fields with appropriate frequencies. By detuning the probe lasers slightly from the ``dark resonance'', we observe that atoms can be significantly cooled down by the strong viscous force within the transparency window, while being just slightly heated by the diffusion caused by the small absorption near resonance. In contrast to polarization gradient cooling or EIT sideband cooling, no external magnetic field or external confining potential are required. Using a semi-classical method, analytical expressions, and numerical simulations, we demonstrate that the proposed EIT cooling method can lead to temperatures well below the Doppler limit. This work is supported by NSF and NIST.

  20. Optimization of evaporative cooling

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Bradley, C. C.; Hulet, R. G.

    1997-05-01

    Recent experiments have used forced evaporative cooling to produce Bose-Einstein condensation in dilute gases. The evaporative cooling process can be optimized to provide the maximum phase-space density with a specified number of atoms remaining. We show that this global optimization is approximately achieved by locally optimizing the cooling efficiency at each instant. We discuss how this method can be implemented, and present the results for our 7Li trap. The predicted behavior of the gas is found to agree well with experiment.

  1. Personal Cooling System

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Cool Head, a personal cooling system for use in heat stress occupations, is a spinoff of a channeled cooling garment for space wear. It is portable and includes a heat exchanger, control display unit, liquid reservoir and temperature control unit. The user can eliminate 40 to 60 percent of his body's heat storage and lower heart rate by 50 to 80 beats a minute. The system is used by the Army, Navy, crop dusting pilots, heavy equipment operators and auto racing drivers and is marketed by Life Enhancement Technologies, LLC. Further applications are under consideration.

  2. Feedback cooling of currents

    NASA Astrophysics Data System (ADS)

    Washburn, Sean

    1989-02-01

    Just as feedback can be used to correct errors in the output voltages of amplifiers, it can also be used to remove noise from the current through a resistor. Such a feedback amplifier behaves as a refrigerator cooling the electrons in a resistor connnected to it. This principle has been recognized since the 1940s but has been largely ignored because the cooling power available from such refrigerators is miniscule. It is pointed out here that the method might be practical for cooling the currents in the microscopic circuits that are typical of modern electrical engineering and recent studies in transport physics.

  3. 53. VIEW LOOKING S.E. AT THE CATALYZER BUILDINGS, COOLING SHEDS ...

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

    53. VIEW LOOKING S.E. AT THE CATALYZER BUILDINGS, COOLING SHEDS AND ABSORPTION BUILDINGS IN THE BACKGROUND. MAY 29, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  4. Polk power station syngas cooling system

    SciTech Connect

    Jenkins, S.D.

    1995-01-01

    Tampa Electric Company (TEC) is in the site development and construction phase of the new Polk Power Station Unit No. 1. This will be the first unit at a new site and will use Integrated Gasification Combined Cycle (IGCC) Technology. The unit will utilize Texaco`s oxygen-blown, entrained-flow coal gasification, along with combined cycle power generation, to produce nominal 260MW. Integral to the gasification process is the syngas cooling system. The design, integration, fabrication, transportation, and erection of this equipment have provided and continue to provide major challenges for this project.

  5. Absorption chillers: Technology for the future

    SciTech Connect

    Garland, P.W.; Garland, R.W.

    1997-12-31

    In an era of heightened awareness of energy efficiency and the associated environmental impacts, many industries worldwide are exploring ``environmentally friendly`` technologies that provide equivalent or improved performance while reducing or eliminating harmful side-effects. The refrigeration and air-conditioning industry, due to its reliance on CFCs and HCFCs, has invested in research in alternatives to the industry standard vapor compression machines. One alternative technology with great promise is chemical absorption. Absorption chillers offer comparable refrigeration output with reduced SO{sub 2}, CO{sub 2}, and NO{sub x} emissions. Absorption chillers do not use CFCs or HCFCs, refrigerants that contribute to ozone depletion and global warming. Additionally, gas-fired absorption chillers can save significant amounts in energy costs when used in combination with a vapor compression chiller in a hybrid system. The hybrid system can take advantage of the comparatively low price of natural gas (per unit ton) and rely on the high performance of vapor compression when electricity prices are lower. The purpose of this article is to provide an introduction for those new to absorption technology as well as a discussion of selected high efficiency cycles, a discussion on the technology of coupling absorption with vapor compression systems to form a hybrid system, and the environmental impacts of absorption.

  6. Advanced Spectral Library (ASTRAL): Cool stars edition

    NASA Astrophysics Data System (ADS)

    Ayres, T. R.

    2013-02-01

    ASTRAL is a project to create high-resolution, high-S/N UV (1150-3200 Å) atlases of bright stars utilizing {HST}/STIS. During Cycle 18 (2010-2011), eight cool star targets were observed, including key objects like Procyon and Betelgeuse, churning through 146 orbits in the process. The new spectral atlases are publically available through the project website. Data were obtained with the Hubble Space Telescope.

  7. Mechano-caloric cooling device

    NASA Technical Reports Server (NTRS)

    Frederking, T. H. K.; Luna, Jack; Abbassi, P.; Carandang, R. M.

    1989-01-01

    The mechano-caloric effect is potentially useful in the He II temperature range. Aside from demonstration work, little quantification effort appears to have been known since other refrigeration possibilities have been available for some time. Successful He II use-related system examples are as follows: in space, the utilization of the latent heat of vaporization has been quite successful in vapor-liquid phase separation (VLPS) in conjunction with thermomechanical force application in plugs. In magnet cooling systems, the possibility of using the mechano-caloric cooling effect in conjunction with thermo-mechanical circulation pump schemes, has been assessed (but not quantified yet to the extent desirable). A third example is quoted in conjunction with superfluid wind tunnel studies and liquid helium tow tank for surface vessels respectively. In all of these (partially future) R and D areas, the question of refrigerator effectiveness using the mechano-caloric effect appears to be relevant, possibly in conjunction with questions of reliability and simplicity. The present work is concerned with quantification of phenomena including simplified thermodynamic cycle calculations.

  8. Stimulated radiative laser cooling

    NASA Astrophysics Data System (ADS)

    Muys, P.

    2008-04-01

    Building a refrigerator based on the conversion of heat into optical energy is an ongoing engineering challenge. Under well-defined conditions, spontaneous anti-Stokes fluorescence of a dopant material in a host matrix is capable of lowering the host temperature. The fluorescence is conveying away a part of the thermal energy stored in the vibrational oscillations of the host lattice. In particular, applying this principle to the cooling of (solid-state) lasers opens up many potential device applications, especially in the domain of high-power lasers. In this paper, an alternative optical cooling scheme is outlined, leading to the radiative cooling of solid-state lasers. It is based on converting the thermal energy stored in the host into optical energy by means of a stimulated nonlinear process, rather than a spontaneous process. This should lead to better cooling efficiencies and a higher potential of applying the principle for device applications.

  9. Sisyphus cooling of lithium

    NASA Astrophysics Data System (ADS)

    Hamilton, Paul; Kim, Geena; Joshi, Trinity; Mukherjee, Biswaroop; Tiarks, Daniel; Müller, Holger

    2014-02-01

    Laser cooling to sub-Doppler temperatures by optical molasses is thought to be inhibited in atoms with unresolved, near-degenerate hyperfine structure in the excited state. We demonstrate that such cooling is possible in one to three dimensions, not only near the standard D2 line for laser cooling, but over a wide range extending to the D1 line. Via a combination of Sisyphus cooling followed by adiabatic expansion, we reach temperatures as low as 40 μK, which corresponds to atomic velocities a factor of 2.6 above the limit imposed by a single-photon recoil. Our method requires modest laser power at a frequency within reach of standard frequency-locking methods. It is largely insensitive to laser power, polarization and detuning, magnetic fields, and initial hyperfine populations. Our results suggest that optical molasses should be possible with all alkali-metal species.

  10. Why Exercise Is Cool

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Why Exercise Is Cool KidsHealth > For Kids > Why Exercise Is ... day and your body will thank you later! Exercise Makes Your Heart Happy You may know that ...

  11. Cooling of dense stars

    NASA Technical Reports Server (NTRS)

    Tsuruta, S.

    1972-01-01

    Cooling rates were calculated for neutron stars of about one solar mass and 10 km radius, with magnetic fields from zero to about 10 to the 14th power gauss, for extreme cases of maximum and zero superfluidity. The results show that most pulsars are so cold that thermal ionization of surface atoms would be negligible. Nucleon superfluidity and crystallization of heavy nuclei were treated quantitatively, and more realistic hadron star models were chosen. Cooling rates were calculated for a stable hyperon star near the maximum mass limit, a medium weight neutron star, and a light neutron star with neutron-rich heavy nuclei near the minimum mass limit. Results show that cooling rates are a sensitive function of density. The Crab and Vela pulsars are considered, as well as cooling of a massive white dwarf star.

  12. Too cool to work

    NASA Astrophysics Data System (ADS)

    Moya, Xavier; Defay, Emmanuel; Heine, Volker; Mathur, Neil D.

    2015-03-01

    Magnetocaloric and electrocaloric effects are driven by doing work, but this work has barely been explored, even though these caloric effects are being exploited in a growing number of prototype cooling devices.

  13. Warm and Cool Dinosaurs.

    ERIC Educational Resources Information Center

    Mannlein, Sally

    2001-01-01

    Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of warm and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)

  14. Waveguide cooling system

    NASA Technical Reports Server (NTRS)

    Chen, B. C. J.; Hartop, R. W. (Inventor)

    1981-01-01

    An improved system is described for cooling high power waveguides by the use of cooling ducts extending along the waveguide, which minimizes hot spots at the flanges where waveguide sections are connected together. The cooling duct extends along substantially the full length of the waveguide section, and each flange at the end of the section has a through hole with an inner end connected to the duct and an opposite end that can be aligned with a flange hole in another waveguide section. Earth flange is formed with a drainage groove in its face, between the through hole and the waveguide conduit to prevent leakage of cooling fluid into the waveguide. The ducts have narrowed sections immediately adjacent to the flanges to provide room for the installation of fasteners closely around the waveguide channel.

  15. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Moskito, John (Inventor)

    1999-01-01

    An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

  16. WATER COOLED RETORT COVER

    DOEpatents

    Ash, W.J.; Pozzi, J.F.

    1962-05-01

    A retort cover is designed for use in the production of magnesium metal by the condensation of vaporized metal on a collecting surface. The cover includes a condensing surface, insulating means adjacent to the condensing surface, ind a water-cooled means for the insulating means. The irrangement of insulation and the cooling means permits the magnesium to be condensed at a high temperature and in massive nonpyrophoric form. (AEC)

  17. Liquid cooled helmet

    NASA Technical Reports Server (NTRS)

    Elkins, William (Inventor); Williams, Bill A. (Inventor)

    1979-01-01

    Liquid cooled helmet comprising a cap of flexible material adapted to fit the head of a person, cooling panels mounted inside the cap forming passageways for carrying a liquid coolant, the panels being positioned to engage the cranium and neck of a person wearing the helmet, inlet and outlet lines communicating with the passageways, and releasable straps for securing the helmet about the neck of the wearer.

  18. Laser cooling of solids

    SciTech Connect

    Epstein, Richard I; Sheik-bahae, Mansoor

    2008-01-01

    We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

  19. Refrigerant directly cooled capacitors

    DOEpatents

    Hsu, John S.; Seiber, Larry E.; Marlino, Laura D.; Ayers, Curtis W.

    2007-09-11

    The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

  20. Stirling cycle cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P.

    1983-06-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  1. Stirling cycle cryogenic cooler

    NASA Technical Reports Server (NTRS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P. (Inventor)

    1983-01-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  2. Variants of closing the nuclear fuel cycle

    NASA Astrophysics Data System (ADS)

    Andrianova, E. A.; Davidenko, V. D.; Tsibulskiy, V. F.; Tsibulskiy, S. V.

    2015-12-01

    Influence of the nuclear energy structure, the conditions of fuel burnup, and accumulation of new fissile isotopes from the raw isotopes on the main parameters of a closed fuel cycle is considered. The effects of the breeding ratio, the cooling time of the spent fuel in the external fuel cycle, and the separation of the breeding area and the fissile isotope burning area on the parameters of the fuel cycle are analyzed.

  3. Variants of closing the nuclear fuel cycle

    SciTech Connect

    Andrianova, E. A. Davidenko, V. D.; Tsibulskiy, V. F.; Tsibulskiy, S. V.

    2015-12-15

    Influence of the nuclear energy structure, the conditions of fuel burnup, and accumulation of new fissile isotopes from the raw isotopes on the main parameters of a closed fuel cycle is considered. The effects of the breeding ratio, the cooling time of the spent fuel in the external fuel cycle, and the separation of the breeding area and the fissile isotope burning area on the parameters of the fuel cycle are analyzed.

  4. United States Department of Energy large commercial absorption chiller development program

    SciTech Connect

    Garland, P.W.; DeVault, R.C.; Zaltash, A.

    1998-11-01

    The US Department of Energy (DOE) is working with partners from the gas cooling industry to improve energy efficiency and US competitiveness by using advanced absorption technologies that eliminate the use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), refrigerants that contribute to ozone depletion and global warming. Absorption cooling uses natural gas as the heat source, which produces much lower NO{sub x} emissions than oil- or coal-generated electricity. Gas-fired chillers also have the advantage of helping reduce peak electrical usage during summer months. To assist industry in developing advanced absorption cooling technologies, DOE sponsors the Large Commercial Chiller Development Program. The goal of the program is to improve chiller cooling efficiency by 30--50% compared with the best currently available absorption systems.

  5. Solar-Heated and Cooled Office Building--Columbus, Ohio

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Final report documents solar-energy system installed in office building to provide space heating, space cooling and domestic hot water. Collectors mounted on roof track Sun and concentrate rays on fluid-circulating tubes. Collected energy is distributed to hot-water-fired absorption chiller and space-heating and domestic-hot-water preheating systems.

  6. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-07-01

    This eighteenth quarterly technical progress report of the MHD Integrated Topping cycle Project presents the accomplishments during the period November 1, 1991 to January 31, 1992. The precombustor is fully assembled. Manufacturing of all slagging stage components has been completed. All cooling panels were welded in place and the panel/shell gap was filled with RTV. Final combustor assembly is in progress. The low pressure cooling subsystem (LPCS) was delivered to the CDIF. Second stage brazing issues were resolved. The construction of the two anode power cabinets was completed.

  7. Nonlinear microwave absorption in weak-link Josephson junctions

    SciTech Connect

    Xie, L.M.; Wosik, J.; Wolfe, J.C.

    1996-12-01

    A model, based on the resistively shunted junction theory, is developed and used to study microwave absorption in weak-link Josephson junctions in high-{ital T}{sub {ital c}} superconductors. Both linear and nonlinear cases of microwave absorption in Josephson junctions are analyzed. A comparison of the model with microwave absorption loop theory is presented along with a general condition for the applicability of both models. The nonlinear case was solved numerically and the threshold points of sharp microwave absorption are presented. At these points, a 2{pi} phase quantization takes place within each microwave cycle, leading to an onset of a sharp rise of absorption. Existence of the 2{pi} dynamic quantization is the key to the interpretation of nonlinear microwave absorption data. The nonlinear microwave absorption model is extended to the study of nonuniformly coupled junctions, and a general statement for the applicability of such a model is presented. {copyright} {ital 1996 The American Physical Society.}

  8. Comparing Social Stories™ to Cool versus Not Cool

    ERIC Educational Resources Information Center

    Leaf, Justin B.; Mitchell, Erin; Townley-Cochran, Donna; McEachin, John; Taubman, Mitchell; Leaf, Ronald

    2016-01-01

    In this study we compared the cool versus not cool procedure to Social Stories™ for teaching various social behaviors to one individual diagnosed with autism spectrum disorder. The researchers randomly assigned three social skills to the cool versus not cool procedure and three social skills to the Social Stories™ procedure. Naturalistic probes…

  9. Cool Flame Quenching

    NASA Technical Reports Server (NTRS)

    Pearlman, Howard; Chapek, Richard

    2001-01-01

    Cool flame quenching distances are generally presumed to be larger than those associated with hot flames, because the quenching distance scales with the inverse of the flame propagation speed, and cool flame propagation speeds are often times slower than those associated with hot flames. To date, this presumption has never been put to a rigorous test, because unstirred, non-isothermal cool flame studies on Earth are complicated by natural convection. Moreover, the critical Peclet number (Pe) for quenching of cool flames has never been established and may not be the same as that associated with wall quenching due to conduction heat loss in hot flames, Pe approx. = 40-60. The objectives of this ground-based study are to: (1) better understand the role of conduction heat loss and species diffusion on cool flame quenching (i.e., Lewis number effects), (2) determine cool flame quenching distances (i.e, critical Peclet number, Pe) for different experimental parameters and vessel surface pretreatments, and (3) understand the mechanisms that govern the quenching distances in premixtures that support cool flames as well as hot flames induced by spark-ignition. Objective (3) poses a unique fire safety hazard if conditions exist where cool flame quenching distances are smaller than those associated with hot flames. For example, a significant, yet unexplored risk, can occur if a multi-stage ignition (a cool flame that transitions to a hot flame) occurs in a vessel size that is smaller than that associated with the hot quenching distance. To accomplish the above objectives, a variety of hydrocarbon-air mixtures will be tested in a static reactor at elevated temperature in the laboratory (1g). In addition, reactions with chemical induction times that are sufficiently short will be tested aboard NASA's KC-135 microgravity (mu-g) aircraft. The mu-g results will be compared to a numerical model that includes species diffusion, heat conduction, and a skeletal kinetic mechanism

  10. Combined rankine and vapor compression cycles

    DOEpatents

    Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

    2005-04-19

    An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

  11. Simulation and performance analysis of a 4-effect lithium bromide-water absorption chiller

    SciTech Connect

    Grossman, G.; Zaltash, A.; DeVault, R.C.

    1995-02-01

    Performance simulation has been conducted for a 4-effect lithium bromide-water chiller, capable of substantial performance improvement over state-of-the-art double-effect cycles. The system investigated includes four condensers and four desorbers coupled together, forming an extension of the conventional double-effect cycle; based on prior analytical studies, a parallel flow system was preferred over series flow, and double-condenser coupling was employed, to further improve performance. A modular computer code for simulation of absorption systems (ABSIM) was used to investigate the performances of the cycle. The simulation was carried out to investigate the influence of some major design parameters. A coefficient of performance around 2.0 (cooling) was calculated at the design point, with a heat supply temperature of 600{degrees}F (315{degrees}C) at the solution outlet from the high temperature desorber. With some optimization of the weak (pumped) solution flowrate and of the solution split among the four desorbers, this COP may be raised above 2.2.

  12. X ray opacity in cluster cooling flows

    NASA Technical Reports Server (NTRS)

    Wise, Michael W.; Sarazin, Craig L.

    1993-01-01

    We have calculated the emergent x-ray properties for a set of spherically symmetric, steady-state cluster cooling flow models including the effects of radiative transfer. Opacity due to resonant x-ray lines, photoelectric absorption, and electron scattering have been included in these calculations, and homogeneous and inhomogeneous gas distributions were considered. The effects of photoionization opacity are small for both types of models. In contrast, resonant line optical depths can be quite high in both homogeneous and inhomogeneous models. The presence of turbulence in the gas can significantly lower the line opacity. We find that integrated x-ray spectra for the flow cooling now are only slightly affected by radiative transfer effects. However x-ray line surface brightness profiles can be dramatically affected by radiative transfer. Line profiles are also strongly affected by transfer effects. The combined effects of opacity and inflow cause many of the lines in optically thick models to be asymmetrical.

  13. Conservation laws and laser cooling of atoms

    NASA Astrophysics Data System (ADS)

    Giuliani, Giuseppe

    2015-11-01

    The straightforward application of energy and linear momentum conservation to the absorption/emission of photons by atoms allows us to establish the essential features of laser cooling of two level atoms at low laser intensities. The lowest attainable average kinetic energy of the atoms depends on the ratio {{Γ }}/{E}{{R}} between the natural linewidth and the recoil energy and tends to ER as {{Γ }}/{E}{{R}} tends to zero (in one dimension). This treatment, like the quantum mechanical ones, is valid for any value of the ratio {{Γ }}/{E}{{R}} and contains the semiclassical theory of laser cooling as the limiting case in which {E}{{R}}\\ll {{Γ }}.

  14. Heating and cooling of the earth's plasma sheet

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1990-01-01

    Magnetic-field models based on pressure equilibrium in the quiet magnetotail require nonadiabatic cooling of the plasma as it convects inward or a decrease of the flux tube content. Recent in situ observations of plasma density and temperature indicate that, during quiet convection, the flux tube content may actually increase. Thus the plasma must be cooled during quiet times. The earth plasma sheet is generally significantly hotter after the expansion phase of a substorm than before the plasma sheet thinning begins and cools during the recovery phase. Heating mechanisms such as reconnection, current sheet acceleration, plasma expansion, and resonant absorption of surface waves are discussed. It seems that all mechanisms are active, albeit in different regions of the plasma sheet. Near-earth tail signatures of substorms require local heating as well as a decrease of the flux tube content. It is shown that the resonant absorption of surface waves can provide both.

  15. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  16. Cool WISPs for stellar cooling excesses

    NASA Astrophysics Data System (ADS)

    Giannotti, Maurizio; Irastorza, Igor; Redondo, Javier; Ringwald, Andreas

    2016-05-01

    Several stellar systems (white dwarfs, red giants, horizontal branch stars and possibly the neutron star in the supernova remnant Cassiopeia A) show a mild preference for a non-standard cooling mechanism when compared with theoretical models. This exotic cooling could be provided by Weakly Interacting Slim Particles (WISPs), produced in the hot cores and abandoning the star unimpeded, contributing directly to the energy loss. Taken individually, these excesses do not show a strong statistical weight. However, if one mechanism could consistently explain several of them, the hint could be significant. We analyze the hints in terms of neutrino anomalous magnetic moments, minicharged particles, hidden photons and axion-like particles (ALPs). Among them, the ALP or a massless HP represent the best solution. Interestingly, the hinted ALP parameter space is accessible to the next generation proposed ALP searches, such as ALPS II and IAXO and the massless HP requires a multi TeV energy scale of new physics that might be accessible at the LHC.

  17. Tracing inflows and outflows with absorption lines in circumgalactic gas

    NASA Astrophysics Data System (ADS)

    Ford, Amanda Brady; Davé, Romeel; Oppenheimer, Benjamin D.; Katz, Neal; Kollmeier, Juna A.; Thompson, Robert; Weinberg, David H.

    2014-10-01

    We examine how H I and metal absorption lines within low-redshift galaxy haloes trace the dynamical state of circumgalactic gas, using cosmological hydrodynamic simulations that include a well-vetted heuristic model for galactic outflows. We categorize inflowing, outflowing, and ambient gas based on its history and fate as tracked in our simulation. Following our earlier work, showing that the ionization level of absorbers was a primary factor in determining the physical conditions of absorbing gas, we show here that it is also a governing factor for its dynamical state. Low-ionization metal absorbers (e.g. Mg II) tend to arise in gas that will fall on to galaxies within several Gyr, while high-ionization metal absorbers (e.g. O VI) generally trace material that was deposited by outflows many Gyr ago. Inflowing gas is dominated by enriched material that was previously ejected in an outflow; hence, accretion at low redshifts is typically substantially enriched. Recycling wind material is preferentially found closer to galaxies, and is more dominant in lower mass haloes since high-mass haloes have more hot gas that is able to support itself against infall. Low-mass haloes also tend to re-eject more of their accreted material, owing to our outflow prescription that employs higher mass loading factors for lower mass galaxies. Typical H I absorbers trace unenriched ambient material that is not participating in the baryon cycle, but stronger H I absorbers arise in cool, enriched inflowing gas. Instantaneous radial velocity measures of absorbers are generally poor at distinguishing between inflowing and outflowing gas, except in the case of very recent outflows. These results suggest that probing halo gas using a range of absorbers can provide detailed information about the amount and physical conditions of material that is participating in the baryon cycle.

  18. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  19. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-06-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  20. System and method for cooling a combustion gas charge

    DOEpatents

    Massey, Mary Cecelia; Boberg, Thomas Earl

    2010-05-25

    The present invention relates to a system and method for cooling a combustion gas charge prior. The combustion gas charge may include compressed intake air, exhaust gas, or a mixture thereof. An evaporator is provided that may then receive a relatively high temperature combustion gas charge and discharge at a relatively lower temperature. The evaporator may be configured to operate with refrigeration cycle components and/or to receive a fluid below atmospheric pressure as the phase-change cooling medium.

  1. Percutaneous absorption of drugs.

    PubMed

    Wester, R C; Maibach, H I

    1992-10-01

    The skin is an evolutionary masterpiece of living tissue which is the final control unit for determining the local and systemic availability of any drug which must pass into and through it. In vivo in humans, many factors will affect the absorption of drugs. These include individual biological variation and may be influenced by race. The skin site of the body will also influence percutaneous absorption. Generally, those body parts exposed to the open environment (and to cosmetics, drugs and hazardous toxic substances) are most affected. Treating patients may involve single daily drug treatment or multiple daily administration. Finally, the body will be washed (normal daily process or when there is concern about skin decontamination) and this will influence percutaneous absorption. The vehicle of a drug will affect release of drug to skin. On skin, the interrelationships of this form of administration involve drug concentration, surface area exposed, frequency and time of exposure. These interrelationships determine percutaneous absorption. Accounting for all the drug administered is desirable in controlled studies. The bioavailability of the drug then is assessed in relationship to its efficacy and toxicity in drug development. There are methods, both quantitative and qualitative, in vitro and in vivo, for studying percutaneous absorption of drugs. Animal models are substituted for humans to determine percutaneous absorption. Each of these methods thus becomes a factor in determining percutaneous absorption because they predict absorption in humans. The relevance of these predictions to humans in vivo is of intense research interest. The most relevant determination of percutaneous absorption of a drug in humans is when the drug in its approved formulation is applied in vivo to humans in the intended clinical situation. Deviation from this scenario involves the introduction of variables which may alter percutaneous absorption. PMID:1296607

  2. Hybrid Cooling for Geothermal Power Plants: Final ARRA Project Report

    SciTech Connect

    Bharathan, D.

    2013-06-01

    Many binary-cycle geothermal plants use air as the heat rejection medium. Usually this is accomplished by using an air-cooled condenser (ACC) system to condense the vapor of the working fluid in the cycle. Many air-cooled plants suffer a loss of production capacity of up to 50% during times of high ambient temperatures. Use of limited amounts of water to supplement the performance of ACCs is investigated. Deluge cooling is found to be one of the least-cost options. Limiting the use of water in such an application to less than one thousand operating hours per year can boost plant output during critical high-demand periods while minimizing water use in binary-cycle geothermal power plants.

  3. Cooling System Using Natural Circulation for Air Conditioning

    NASA Astrophysics Data System (ADS)

    Okazaki, Takashi; Seshimo, Yu

    In this paper, Cooling systems with natural circulation loop of refrigerants are reviewed. The cooling system can largely reduce energy consumption of a cooling system for the telecommunication base site. The cooling system consists of two refrigeration units; vapor compression refrigeration unit and sub-cooling unit with a natural-circulation loop. The experiments and calculations were carried out to evaluate the cycle performance of natural circulation loop with HFCs and CO2. The experimental results showed that the cooling capacity of R410A is approximately 30% larger than that of R407C at the temperature difference of 20K and the cooling capacity of CO2 was approximately 4-13% larger than that of R410A under the two-phase condition. On the other hand, the cooling capacity of CO2 was approximately 11% smaller than that of R410A under the supercritical condition. The cooling capacity took a maximum value at an amount of refrigerant and lineally increased as the temperature difference increases and the slightly increased as the height difference. The air intake temperature profile in the inlet of the heat exchangers makes the reverse circulation under the supercritical state and the driving head difference for the reverse circulation depends on the density change to temperature under the supercritical state. Also, a new fan control method to convert the reverse circulation into the normal circulation was reviewed.

  4. Cycle Analysis

    2012-03-20

    1. The Cycle Analysis code is an Microsoft Excel code that performs many different types of thermodynamic cycle analysis for power producing systems. The code will calculate the temperature and pressure and all other thermodynamic properties at the inlet and outlet of each component. The code also calculates the power that is produced, the efficiency, and the heat transported in the heater, gas chiller and recuperators. The code provides a schematic of the loop andmore » provides the temperature and pressure at each location in the loop. The code also provides a T-S (temperature-entropy) diagram of the loop and often it provides an pressure enthalpy plot as well. 2. This version of the code concentrates on supercritical CO2 power cycles, but by simply changing the name of the working fluid many other types of fluids can be analyzed. The Cycle Analysis code provided here contains 18 different types of power cycles. Each cycle is contained in one worksheet or tab that the user can select. The user can change the yellow highlighted regions to perform different thermodynamic cycle analysis.« less

  5. Cooling in a compound bucket

    SciTech Connect

    Shemyakin, A.; Bhat, C.; Broemmelsiek, D.; Burov, A.; Hu, M.; /Fermilab

    2007-09-01

    Electron cooling in the Fermilab Recycler ring is found to create correlation between longitudinal and transverse tails of the antiproton distribution. By separating the core of the beam from the tail and cooling the tail using 'gated' stochastic cooling while applying electron cooling on the entire beam, one may be able to significantly increase the overall cooling rate. In this paper, we describe the procedure and first experimental results.

  6. Passive containment cooling system

    DOEpatents

    Billig, P.F.; Cooke, F.E.; Fitch, J.R.

    1994-01-25

    A passive containment cooling system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel and is vented to the drywell. An isolation pool is disposed above the GDCS pool and includes an isolation condenser therein. The condenser has an inlet line disposed in flow communication with the drywell for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser also has an outlet line disposed in flow communication with the drywell for returning to the drywell both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA. 1 figure.

  7. STOCHASTIC COOLING FOR RHIC.

    SciTech Connect

    BLASKIEWICZ,M.BRENNAN,J.M.CAMERON,P.WEI,J.

    2003-05-12

    Emittance growth due to Intra-Beam Scattering significantly reduces the heavy ion luminosity lifetime in RHIC. Stochastic cooling of the stored beam could improve things considerably by counteracting IBS and preventing particles from escaping the rf bucket [1]. High frequency bunched-beam stochastic cooling is especially challenging but observations of Schottky signals in the 4-8 GHz band indicate that conditions are favorable in RHIC [2]. We report here on measurements of the longitudinal beam transfer function carried out with a pickup kicker pair on loan from FNAL TEVATRON. Results imply that for ions a coasting beam description is applicable and we outline some general features of a viable momentum cooling system for RHIC.

  8. Cooling of neutron stars

    NASA Technical Reports Server (NTRS)

    Pethick, C. J.

    1992-01-01

    It is at present impossible to predict the interior constitution of neutron stars based on theory and results from laboratory studies. It has been proposed that it is possible to obtain information on neutron star interiors by studying thermal radiation from their surfaces, because neutrino emission rates, and hence the temperature of the central part of a neutron star, depend on the properties of dense matter. The theory predicts that neutron stars cool relatively slowly if their cores are made up of nucleons, and cool faster if the matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been questioned by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

  9. Monitoring Cray Cooling Systems

    SciTech Connect

    Maxwell, Don E; Ezell, Matthew A; Becklehimer, Jeff; Donovan, Matthew J; Layton, Christopher C

    2014-01-01

    While sites generally have systems in place to monitor the health of Cray computers themselves, often the cooling systems are ignored until a computer failure requires investigation into the source of the failure. The Liebert XDP units used to cool the Cray XE/XK models as well as the Cray proprietary cooling system used for the Cray XC30 models provide data useful for health monitoring. Unfortunately, this valuable information is often available only to custom solutions not accessible by a center-wide monitoring system or is simply ignored entirely. In this paper, methods and tools used to harvest the monitoring data available are discussed, and the implementation needed to integrate the data into a center-wide monitoring system at the Oak Ridge National Laboratory is provided.

  10. Passive containment cooling system

    DOEpatents

    Billig, Paul F.; Cooke, Franklin E.; Fitch, James R.

    1994-01-01

    A passive containment cooling system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel and is vented to the drywell. An isolation pool is disposed above the GDCS pool and includes an isolation condenser therein. The condenser has an inlet line disposed in flow communication with the drywell for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser also has an outlet line disposed in flow communication with the drywell for returning to the drywell both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA.

  11. Assessment of the Thermal Advantages of Biased Supersonic Cooling

    NASA Astrophysics Data System (ADS)

    Carkin, Michael J.

    The following work investigates an alternative supersonic film cooling method for hydrogen-fueled, gas-generator cycle rocket engines. The research is intended to serve as an initial proof-of-concept for a biased supersonic film cooling method envisioned for nozzle extension thermal management. The proposed method utilizes a dual-stream injection process that leverages the high heat capacity of the fuel-rich gas-generator gases. By comparing the proposed cooling strategy to the conventional mixed injection process, the research numerically validates the biased supersonic film cooling scheme for low supersonic slot Mach numbers. The average film cooling effectiveness was improved 5%-8% with increases as high as 12%. The average reduction in wall temperature ranged from 9%-15% with maximum reductions as high as 36% over the conventional method.

  12. Combustor liner cooling system

    DOEpatents

    Lacy, Benjamin Paul; Berkman, Mert Enis

    2013-08-06

    A combustor liner is disclosed. The combustor liner includes an upstream portion, a downstream end portion extending from the upstream portion along a generally longitudinal axis, and a cover layer associated with an inner surface of the downstream end portion. The downstream end portion includes the inner surface and an outer surface, the inner surface defining a plurality of microchannels. The downstream end portion further defines a plurality of passages extending between the inner surface and the outer surface. The plurality of microchannels are fluidly connected to the plurality of passages, and are configured to flow a cooling medium therethrough, cooling the combustor liner.

  13. Cyclic cooling algorithm

    SciTech Connect

    Rempp, Florian; Mahler, Guenter; Michel, Mathias

    2007-09-15

    We introduce a scheme to perform the cooling algorithm, first presented by Boykin et al. in 2002, for an arbitrary number of times on the same set of qbits. We achieve this goal by adding an additional SWAP gate and a bath contact to the algorithm. This way one qbit may repeatedly be cooled without adding additional qbits to the system. By using a product Liouville space to model the bath contact we calculate the density matrix of the system after a given number of applications of the algorithm.

  14. Anomalous law of cooling

    SciTech Connect

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  15. Superconductor rotor cooling system

    DOEpatents

    Gamble, Bruce B.; Sidi-Yekhlef, Ahmed; Schwall, Robert E.; Driscoll, David I.; Shoykhet, Boris A.

    2002-01-01

    A system for cooling a superconductor device includes a cryocooler located in a stationary reference frame and a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with a rotating reference frame in which the superconductor device is located. A method of cooling a superconductor device includes locating a cryocooler in a stationary reference frame, and transferring heat from a superconductor device located in a rotating reference frame to the cryocooler through a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with the rotating reference frame.

  16. Anomalous law of cooling.

    PubMed

    Lapas, Luciano C; Ferreira, Rogelma M S; Rubí, J Miguel; Oliveira, Fernando A

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics. PMID:25770525

  17. Anomalous law of cooling

    NASA Astrophysics Data System (ADS)

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-01

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  18. Superconductor rotor cooling system

    DOEpatents

    Gamble, Bruce B.; Sidi-Yekhlef, Ahmed; Schwall, Robert E.; Driscoll, David I.; Shoykhet, Boris A.

    2004-11-02

    A system for cooling a superconductor device includes a cryocooler located in a stationary reference frame and a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with a rotating reference frame in which the superconductor device is located. A method of cooling a superconductor device includes locating a cryocooler in a stationary reference frame, and transferring heat from a superconductor device located in a rotating reference frame to the cryocooler through a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with the rotating reference frame.

  19. Research on cooling effectiveness in stepped slot film cooling vane

    NASA Astrophysics Data System (ADS)

    Li, Yulong; Wu, Hong; Zhou, Feng; Rong, Chengjun

    2016-06-01

    As one of the most important developments in air cooling technology for hot parts of the aero-engine, film cooling technology has been widely used. Film cooling hole structure exists mainly in areas that have high temperature, uneven cooling effectiveness issues when in actual use. The first stage turbine vanes of the aero-engine consume the largest portion of cooling air, thereby the research on reducing the amount of cooling air has the greatest potential. A new stepped slot film cooling vane with a high cooling effectiveness and a high cooling uniformity was researched initially. Through numerical methods, the affecting factors of the cooling effectiveness of a vane with the stepped slot film cooling structure were researched. This paper focuses on the cooling effectiveness and the pressure loss in different blowing ratio conditions, then the most reasonable and scientific structure parameter can be obtained by analyzing the results. The results show that 1.0 mm is the optimum slot width and 10.0 is the most reasonable blowing ratio. Under this condition, the vane achieved the best cooling result and the highest cooling effectiveness, and also retained a low pressure loss.

  20. Active cooling requirements for propellant storage

    NASA Technical Reports Server (NTRS)

    Klein, G. A.

    1984-01-01

    Recent NASA and DOD mission models have indicated future needs for orbital cryogenic storage and supply systems. Two thermal control systems which show the greatest promise for improving propellant storage life were evaluated. One system was an open cycle thermodynamic vent type with a refrigeration system for partial hydrogen reliquefaction located at the LH2 tank and a vapor cooled shield for integrated and non-integrated tank designs to reduce boiloff. The other was a closed system with direct refrigeration at the LH2 tank. A reversed Brayton cycle unit was baselined for the propellant processor. It is concluded that: (1) reliquefaction systems are not attractive for minimizing propellant boiloff; (2) open cycle systems may not be economically attractive for long term storage; (3) a number of refrigeration systems are available to assist in the long term storage of cryogenic propellants; and (4) shields can significantly improve the performance of mechanical coolers.

  1. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  2. Cooling athletes with a spinal cord injury.

    PubMed

    Griggs, Katy E; Price, Michael J; Goosey-Tolfrey, Victoria L

    2015-01-01

    Cooling strategies that help prevent a reduction in exercise capacity whilst exercising in the heat have received considerable research interest over the past 3 decades, especially in the lead up to a relatively hot Olympic and Paralympic Games. Progressing into the next Olympic/Paralympic cycle, the host, Rio de Janeiro, could again present an environmental challenge for competing athletes. Despite the interest and vast array of research into cooling strategies for the able-bodied athlete, less is known regarding the application of these cooling strategies in the thermoregulatory impaired spinal cord injured (SCI) athletic population. Individuals with a spinal cord injury (SCI) have a reduced afferent input to the thermoregulatory centre and a loss of both sweating capacity and vasomotor control below the level of the spinal cord lesion. The magnitude of this thermoregulatory impairment is proportional to the level of the lesion. For instance, individuals with high-level lesions (tetraplegia) are at a greater risk of heat illness than individuals with lower-level lesions (paraplegia) at a given exercise intensity. Therefore, cooling strategies may be highly beneficial in this population group, even in moderate ambient conditions (~21 °C). This review was undertaken to examine the scientific literature that addresses the application of cooling strategies in individuals with an SCI. Each method is discussed in regards to the practical issues associated with the method and the potential underlying mechanism. For instance, site-specific cooling would be more suitable for an athlete with an SCI than whole body water immersion, due to the practical difficulties of administering this method in this population group. From the studies reviewed, wearing an ice vest during intermittent sprint exercise has been shown to decrease thermal strain and improve performance. These garments have also been shown to be effective during exercise in the able-bodied. Drawing on

  3. Rotating diffuser for pressure recovery in a steam cooling circuit of a gas turbine

    SciTech Connect

    Eldrid, Sacheverel Q.; Salamah, Samir A.; DeStefano, Thomas Daniel

    2002-01-01

    The buckets of a gas turbine are steam-cooled via a bore tube assembly having concentric supply and spent cooling steam return passages rotating with the rotor. A diffuser is provided in the return passage to reduce the pressure drop. In a combined cycle system, the spent return cooling steam with reduced pressure drop is combined with reheat steam from a heat recovery steam generator for flow to the intermediate pressure turbine. The exhaust steam from the high pressure turbine of the combined cycle unit supplies cooling steam to the supply conduit of the gas turbine.

  4. Absorption type water chiller fired directly by waste heat

    NASA Astrophysics Data System (ADS)

    Sauer, K. L.; Kalwar, K.

    1982-08-01

    The direct use of waste heat as heating element in a water chiller of the absorption type was studied. The chilled water is used as cooling element in the industrial process, producing the waste heat or for conditioning the workplace or further located places. The heat source is gaseous or liquid. The cooling capacity is in the range from 10 to 120 kW. After reviewing the different absorption systems, LiBr/H20 proved to be the most suitable. The process retained for experimenting was the manufacturing of synthetic materials polymer industry and was tested in two different factories. It is proved that the use of absorption type water chillers is practicable with an efficiency of 10% to 25% of the waste heat energy, but that the existing chillers need extensive conversion for obtaining economical operation when using a low temperature heating source.

  5. Cycling injuries.

    PubMed Central

    Cohen, G. C.

    1993-01-01

    Bicycle-related injuries have increased as cycling has become more popular. Most injuries to recreational riders are associated with overuse or improper fit of the bicycle. Injuries to racers often result from high speeds, which predispose riders to muscle strains, collisions, and falls. Cyclists contact bicycles at the pedals, seat, and handlebars. Each is associated with particular cycling injuries. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8471908

  6. Laser-driven Sisyphus cooling in an optical dipole trap

    SciTech Connect

    Ivanov, Vladyslav V.; Gupta, Subhadeep

    2011-12-15

    We propose a laser-driven Sisyphus-cooling scheme for atoms confined in a far-off resonance optical dipole trap. Utilizing the differential trap-induced ac Stark shift, two electronic levels of the atom are resonantly coupled by a cooling laser preferentially near the trap bottom. After absorption of a cooling photon, the atom loses energy by climbing the steeper potential, and then spontaneously decays preferentially away from the trap bottom. The proposed method is particularly suited to cooling alkaline-earth-metal-like atoms where two-level systems with narrow electronic transitions are present. Numerical simulations for the cases of {sup 88}Sr and {sup 174}Yb demonstrate the expected recoil and Doppler temperature limits. The method requires a relatively small number of scattered photons and can potentially lead to phase-space densities approaching quantum degeneracy in subsecond time scales.

  7. Laser-driven Sisyphus cooling in an optical dipole trap

    NASA Astrophysics Data System (ADS)

    Ivanov, Vladyslav V.; Gupta, Subhadeep

    2011-12-01

    We propose a laser-driven Sisyphus-cooling scheme for atoms confined in a far-off resonance optical dipole trap. Utilizing the differential trap-induced ac Stark shift, two electronic levels of the atom are resonantly coupled by a cooling laser preferentially near the trap bottom. After absorption of a cooling photon, the atom loses energy by climbing the steeper potential, and then spontaneously decays preferentially away from the trap bottom. The proposed method is particularly suited to cooling alkaline-earth-metal-like atoms where two-level systems with narrow electronic transitions are present. Numerical simulations for the cases of 88Sr and 174Yb demonstrate the expected recoil and Doppler temperature limits. The method requires a relatively small number of scattered photons and can potentially lead to phase-space densities approaching quantum degeneracy in subsecond time scales.

  8. Effect of tropospheric aerosols upon atmospheric infrared cooling rates

    NASA Technical Reports Server (NTRS)

    Harshvardhan, MR.; Cess, R. D.

    1978-01-01

    The effect of tropospheric aerosols on atmospheric infrared cooling rates is investigated by the use of recent models of infrared gaseous absorption. A radiative model of the atmosphere that incorporates dust as an absorber and scatterer of infrared radiation is constructed by employing the exponential kernel approximation to the radiative transfer equation. Scattering effects are represented in terms of a single scattering albedo and an asymmetry factor. The model is applied to estimate the effect of an aerosol layer made of spherical quartz particles on the infrared cooling rate. Calculations performed for a reference wavelength of 0.55 microns show an increased greenhouse effect, where the net upward flux at the surface is reduced by 10% owing to the strongly enhanced downward emission. There is a substantial increase in the cooling rate near the surface, but the mean cooling rate throughout the lower troposphere was only 10%.

  9. Selective radiative cooling with MgO and/or LiF layers

    DOEpatents

    Berdahl, Paul H.

    1986-01-01

    A material for a wavelength-selective radiative cooling system, the material comprising an infrared-reflective substrate coated with magnesium oxide and/or lithium fluoride in a polycrystalline form. The material is non-absorptive for short wavelengths, absorptive from 8 to 13 microns, and reflective at longer wavelengths. The infrared-reflective substrate inhibits absorption at wavelengths shorter than 8 microns, and the magnesium oxide and/or lithium fluoride layers reflect radiation at wavelengths longer than 13 microns.

  10. Use of a temperature-initiated passive cooling system (TIPACS) for the modular high-temperature gas-cooled reactor cavity cooling system (RCCS)

    SciTech Connect

    Forsberg, C.W.; Conklin, J.; Reich, W.J.

    1994-04-01

    A new type of passive cooling system has been invented (Forsberg 1993): the Temperature-Initiated Passive Cooling System (TIPACS). The characteristics of the TIPACS potentially match requirements for an improved reactor-cavity-cooling system (RCCS) for the modular high-temperature gas-cooled reactor (MHTGR). This report is an initial evaluation of the TIPACS for the MHTGR with a Rankines (steam) power conversion cycle. Limited evaluations were made of applying the TIPACS to MHTGRs with reactor pressure vessel temperatures up to 450 C. These temperatures may occur in designs of Brayton cycle (gas turbine) and process heat MHTGRs. The report is structured as follows. Section 2 describes the containment cooling issues associated with the MHTGR and the requirements for such a cooling system. Section 3 describes TIPACS in nonmathematical terms. Section 4 describes TIPACS`s heat-removal capabilities. Section 5 analyzes the operation of the temperature-control mechanism that determines under what conditions the TIPACS rejects heat to the environment. Section 6 addresses other design and operational issues. Section 7 identifies uncertainties, and Section 8 provides conclusions. The appendixes provide the detailed data and models used in the analysis.

  11. Nutrient cycling.

    PubMed

    Bormann, F H; Likens, G E

    1967-01-27

    The small-watershed approach to problems of nutrient cycling has these advantages. (i) The small watershed is a natural unit of suitable size for intensive study of nutrient cycling at the ecosystem level. (ii) It provides a means of reducing to a minimum, or virtually eliminating, the effect of the difficult-to-measure variables of geologic input and nutrient losses in deep seepage. Control of these variables makes possible accurate measurement of nutrient input and output (erosion) and therefore establishes the relationship of the smaller ecosystem to the larger biospheric cycles. (iii) The small-watershed approach provides a method whereby such important parameters as nutrient release from minerals (weathering) and annual nutrient budgets may be calculated. (iv) It provides a means of studying the interrelationships between the biota and the hydrologic cycle, various nutrient cycles, and energy flow in a single system. (v) Finally, with the small-watershed system we can test the effect of various land-management practices or environmental pollutants on nutrient cycling in natural systems. PMID:17737551

  12. Short-Cycle Adsorption Refrigerator

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1988-01-01

    Modular adsorption/Joule-Thomson-effect refrigerator offers fast regeneration; adsorption/desorption cycle time expected to be 1 minute. Pressurized hydrogen generated by bank of compressor modules during heating phase passes through system of check valves and expands in Joule-Thomson junction as it enters refrigeration chamber. Hydrogen absorbs heat from load before it is sucked out by another bank of compressor modules in cooling phase.

  13. Turbomachine rotor with improved cooling

    DOEpatents

    Hultgren, K.G.; McLaurin, L.D.; Bertsch, O.L.; Lowe, P.E.

    1998-05-26

    A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn. 5 figs.

  14. Turbomachine rotor with improved cooling

    DOEpatents

    Hultgren, Kent Goran; McLaurin, Leroy Dixon; Bertsch, Oran Leroy; Lowe, Perry Eugene

    1998-01-01

    A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn.

  15. Desiccant cooling using unglazed transpired solar collectors

    NASA Astrophysics Data System (ADS)

    Pesaran, A. A.; Wipke, K.

    1992-05-01

    The use of unglazed solar collectors for desiccant regeneration in a solid desiccant cooling cycle was investigated because these collectors are lower in cost than conventional glazed flat-plate collectors. Using computer models, the performance of a desiccant cooling ventilation cycle integrated with either unglazed transpired collectors or conventional glazed flat-plate collectors was obtained. We found that the thermal performance of the unglazed system was lower than the thermal performance of the glazed system because the unglazed system could not take advantage of the heat of adsorption released during the dehumidification process. For a 3-ton cooling system, although the area required for the unglazed collector was 69 percent more than that required for the glazed collector, the cost of the unglazed collector array was 44 percent less than the cost of the glazed collector array. The simple payback period of the unglazed system was half of the payback period of the glazed collector when compared to an equivalent gas-fired system. Although the use of unglazed transpired collectors makes economic sense, some practical considerations may limit their use in desiccant regeneration.

  16. CO2 cooling in terrestrial planet thermospheres

    NASA Technical Reports Server (NTRS)

    Bougher, S. W.; Hunten, D. M.; Roble, R. G.

    1994-01-01

    We examine the recent progress in the debate on the CO2-O relaxation rate, its temperature dependence, and its corresponding impact on the thermospheric heat budgets of Venus, Earth, and Mars. This comparative approach provides the broadest range of conditions under which a common CO2-O relaxation rate should provide consistent results. New global mean calculations are presented for the heat budgets of these three planets using large CO2-O relaxation rates that have been inferred recently from Earth CO2 radiance measurements and laboratory studies. Results indicate that available Venus and Mars data constrain the CO2-O relaxation rate to be 2-4 x 10(exp -12)/cu cm/s at 300 K. For Venus, this strong cooling serves as an effective thermostat that gives rise to a small variation of thermospheric temperatures over the solar cycle, just as observed. Conversely, CO2 cooling does not appear to be dominant in the dayside heat budget of the Mars thermosphere over most of the solar cycle. For the Earth, this strong cooling implies that the lower thermosphere does not typically require significant eddy diffusion or heat conduction. However, global-scale dynamics or an additional heating mechanism may be needed to restore calculated temperatures to observed values when relaxation rates exceeding 2 x 10(exp -12)/cu cm/s are employed.

  17. Measure Guideline: Ventilation Cooling

    SciTech Connect

    Springer, D.; Dakin, B.; German, A.

    2012-04-01

    The purpose of this measure guideline is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  18. Electron Cooling of RHIC

    SciTech Connect

    I. Ben-Zvi; D.S. Barton; D.B. Beavis; M. Blaskiewicz; J.M. Brennan; A. Burrill; R. Calaga; P. Cameron; X.Y. Chang; R. Connolly; Yu.I. Eidelman; A.V. Fedotov; W. Fischer; D.M. Gassner; H. Hahn; M. Harrison; A. Hershcovitch; H.-C. Hseuh; A.K. Jain; P.D.J. Johnson; D. Kayran; J. Kewisch; R.F. Lambiase; V. Litvinenko; W.W. MacKay; G.J. Mahler; N. Malitsky; G.T. McIntyre; W. Meng; K.A.M. Mirabella; C. Montag; T.C.N. Nehring; T. Nicoletti; B. Oerter; G. Parzen; D. Pate; J. Rank; T. Rao; T. Roser; T. Russo; J. Scaduto; K. Smith; D. Trbojevic; G. Wang; J. Wei; N.W.W. Williams; K.-C. Wu; V. Yakimenko; A. Zaltsman; Y. Zhao; D.T. Abell; D.L. Bruhwiler; H. Bluem; A. Burger; M.D. Cole; A.J. Favale; D. Holmes; J. Rathke; T. Schultheiss; A.M.M. Todd; A.V. Burov; S. Nagaitsev; J.R. Delayen; Y.S. Derbenev; L. W. Funk; P. Kneisel; L. Merminga; H.L. Phillips; J.P. Preble; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; J.S. Sekutowicz

    2005-05-16

    We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV. A Zeroth Order Design Report is in an advanced draft state, and can be found on the web at http://www.agsrhichome.bnl.gov/eCool/.

  19. Guide to Cool Roofs

    SciTech Connect

    2011-02-01

    Traditional dark-colored roofing materials absorb sunlight, making them warm in the sun and increasing the need for air conditioning. White or special "cool color" roofs absorb less sunlight, stay cooler in the sun and transmit less heat into the building.

  20. Elementary stochastic cooling

    SciTech Connect

    Tollestrup, A.V.; Dugan, G

    1983-12-01

    Major headings in this review include: proton sources; antiproton production; antiproton sources and Liouville, the role of the Debuncher; transverse stochastic cooling, time domain; the accumulator; frequency domain; pickups and kickers; Fokker-Planck equation; calculation of constants in the Fokker-Planck equation; and beam feedback. (GHT)