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Sample records for absorb thermal energy

  1. Development of a carbonaceous selective absorber for solar thermal energy collection and process for its formation

    NASA Astrophysics Data System (ADS)

    Garrison, John D.

    1989-02-01

    The main goal of the US Department of Energy supported part of this project is to develop information about controlling the complicated chemical processes involved in the formation of a carbonaceous selective absorber and learn what equipment will allow production of this absorber commercially. The work necessary to accomplish this goal is not yet complete. Formation of the carbonaceous selective absorber in the conveyor oven tried so far has been unsatisfactory, because the proper conditions for applying the carbonaceous coating in each conveyor oven fabricated, either have been difficult to obtain, or have been difficult to maintain over an extended period of time. A new conveyor oven is nearing completion which is expected to allow formation of the carbonaceous selective absorber on absorber tubes in a continuous operation over many days without the necessity of cleaning the conveyor oven or changing the thickness of the electroplated nickel catalyst to compensate for changes in the coating environment in the oven. Work under this project concerned with forming and sealing glass panels to test ideas on evacuated glass solar collector designs and production have been generally quite satisfactory. Delays in completion of the selective absorber work, has caused postponement of the fabrication of a small prototype evacuated glass solar collector panel. Preliminary cost estimates of the selective absorber and solar collector panel indicate that this collector system should be lower in cost than evacuated solar collectors now on the market.

  2. Apollo couch energy absorbers

    NASA Technical Reports Server (NTRS)

    Wesselski, C. J.; Drexel, R. E.

    1972-01-01

    Load attenuators for the Apollo spacecraft crew couch and its potential applications are described. Energy absorption is achieved through friction and cyclic deformation of material. In one concept, energy absorption is accomplished by rolling a compressed ring of metal between two surfaces. In another concept, energy is absorbed by forcing a plastically deformed washer along a rod. Among the design problems that had to be solved were material selection, fatigue life, ring slippage, lubrication, and friction loading.

  3. Demonstration of thermal dissipation of absorbed quanta during energy-dependent quenching of chlorophyll fluorescence in photosynthetic membranes.

    PubMed

    Yahyaoui, W; Harnois, J; Carpentier, R

    1998-11-27

    When plant leaves or chloroplasts are exposed to illumination that exceeds their photosynthetic capacity, photoprotective mechanisms such as described by the energy-dependent (non-photochemical) quenching of chlorophyll fluorescence are involved. The protective action is attributed to an increased rate constant for thermal dissipation of absorbed quanta. We applied photoacoustic spectroscopy to monitor thermal dissipation in spinach thylakoid membranes together with simultaneous measurement of chlorophyll fluorescence in the presence of inhibitors of opposite action on the formation of delta pH across the thylakoid membrane (tentoxin and nigericin/valinomycin). A linear relationship between the appearance of fluorescence quenching during formation of the delta pH and the reciprocal variation of thermal dissipation was demonstrated. Dicyclohexylcarbodiimide, which is known to prevent protonation of the minor light-harvesting complexes of photosystem II, significantly reduced the formation of fluorescence quenching and the concurrent increase in thermal dissipation. However, the addition of exogenous ascorbate to activate the xanthophyll de-epoxidase increased non-photochemical fluorescence quenching without affecting the measured thermal dissipation. It is concluded that a portion of energy-dependent fluorescence quenching that is independent of de-epoxidase activity can be readily measured by photoacoustic spectroscopy as an increase in thermal deactivation processes.

  4. Energy absorber for the CETA

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1994-01-01

    The energy absorber that was developed for the CETA (Crew Equipment and Translation Aid) on Space Station Freedom is a metal on metal frictional type and has a load regulating feature that prevents excessive stroking loads from occurring while in operation. This paper highlights some of the design and operating aspects and the testing of this energy absorber.

  5. Metal-shearing energy absorber

    NASA Technical Reports Server (NTRS)

    Fay, R. J.; Wittrock, E. P.

    1971-01-01

    Device, consisting of tongue of thin aluminum alloy strip, pull tab, slotted steel plate which serves as cutter, and steel buckle, absorbs mechanical energy when its ends are subjected to tensile loading. Device is applicable as auxiliary shock absorbing anchor for automobile and airplane safety belts.

  6. Energy Absorbing Protective Shroud

    NASA Technical Reports Server (NTRS)

    Schneider, William C. (Inventor)

    2001-01-01

    The present invention is a dissipating protection energy system designed to receive and safely dissipate the kinetic energy from high energy fragments. The energy dissipation system dissipates energy transferred to it by the incremental and progressive rupturing at an approximately constant force of strategically placed sacrificial stitching applied to a number of high strength straps, such as an aromatic polyimide fiber of extremely high tensile strength. Thus, the energy dissipation system provides a lightweight device for controlling and dissipating the dangerous and destructive energy stored in high strength fragments released by catastrophic failures of machinery minimizing damage to other critical components.

  7. Energy-Absorbing, Lightweight Wheels

    NASA Technical Reports Server (NTRS)

    Waydo, Peter

    2003-01-01

    Improved energy-absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways that result in lighter weights and more effective reduction of stresses generated by ground/wheel contact forces. These wheels could be made of metals and/or composite materials to withstand the expected extreme operating conditions. As shown in the figure, a wheel according to this concept would include an isogrid tire connected to a hub via spring rods. The isogrid tire would be a stiff, lightweight structure typically made of aluminum. The isogrid aspect of the structure would both impart stiffness and act as a traction surface. The hub would be a thin-walled body of revolution having a simple or compound conical or other shape chosen for structural efficiency. The spring rods would absorb energy and partially isolate the hub and the supported vehicle from impact loads. The general spring-rod configuration shown in the figure was chosen because it would distribute contact and impact loads nearly evenly around the periphery of the hub, thereby helping to protect the hub against damage that would otherwise be caused by large loads concentrated onto small portions of the hub.

  8. Thermal energy storage material

    DOEpatents

    Leifer, Leslie

    1976-01-01

    A thermal energy storage material which is stable at atmospheric temperature and pressure and has a melting point higher than 32.degree.F. is prepared by dissolving a specific class of clathrate forming compounds, such as tetra n-propyl or tetra n-butyl ammonium fluoride, in water to form a substantially solid clathrate. The resultant thermal energy storage material is capable of absorbing heat from or releasing heat to a given region as it transforms between solid and liquid states in response to temperature changes in the region above and below its melting point.

  9. Energy absorber uses expanded coiled tube

    NASA Technical Reports Server (NTRS)

    Johnson, E. F.

    1972-01-01

    Mechanical shock mitigating device, based on working material to its failure point, absorbs mechanical energy by bending or twisting tubing. It functions under axial or tangential loading, has no rebound, is area independent, and is easy and inexpensive to build.

  10. Analysis of Energy-Absorbing Foundations.

    DTIC Science & Technology

    1978-12-15

    1ENN51YVAN&A 5TATL UNIV UNIVERSITY PARK DEPT OF ENGI-CYTC F/S 13/h ANALYSIS OF ENERGY -ABSORBING POUNDATIONS.(U) ECC 78 V H NEUBERT, S Ji YIN DNA01-78...C-0036 UNCLASSIFIED DNA-48OFP NL "M~ENOMOEE MIflfl END ______ 1 32 112.2 MICROCOPY RILSOLUTION TEST CHIART LELL ,NA 480 MIL ANALYSIS OF ENERGY ...8217 REPORT & PERIOD COVERED Final Report for Period ANALYSIS OF ENERGY -ABSORBING FOUNDATIONS I Dee 77-1S Dee 78 6. PERFORMING ORG, REPORT NUMBER 7AUTHOR

  11. Seasonal thermal energy storage

    SciTech Connect

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

    1984-05-01

    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  12. Moving core beam energy absorber and converter

    DOEpatents

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  13. Energy deposition studies for the LBNE beam absorber

    SciTech Connect

    Rakhno, Igor L.; Mokhov, Nikolai V.; Tropin, Igor S.

    2015-01-29

    Results of detailed Monte Carlo energy deposition studies performed for the LBNE absorber core and the surrounding shielding with the MARS15 code are described. The model of the entire facility, that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system – all with corresponding radiation shielding – was developed using the recently implemented ROOT-based geometry option in the MARS15 code. This option provides substantial flexibility and automation when developing complex geometry models. Both normal operation and accidental conditions were studied. Various design options were considered, in particular the following: (i) filling the decay pipe with air or helium; (ii) the absorber mask material and shape; (iii) the beam spoiler material and size. Results of detailed thermal calculations with the ANSYS code helped to select the most viable absorber design options.

  14. Optical analysis of solar energy tubular absorbers.

    PubMed

    Saltiel, C; Sokolov, M

    1982-11-15

    The energy absorbed by a solar energy tubular receiver element for a single incident ray is derived. Two types of receiver elements were analyzed: (1) an inner tube with an absorbing coating surrounded by a semitransparent cover tube, and (2) a semitransparent inner tube filled with an absorbing fluid surrounded by a semitransparent cover tube. The formation of ray cascades in the semitransparent tubes is considered. A numerical simulation to investigate the influence of the angle of incidence, sizing, thickness, and coefficient of extinction of the tubes was performed. A comparison was made between receiver elements with and without cover tubes. Ray tracing analyses in which rays were followed within the tubular receiver element as well as throughout the rest of the collector were performed for parabolic and circular trough concentrating collectors.

  15. Thin-film infrared absorber structures for advanced thermal detectors

    NASA Astrophysics Data System (ADS)

    Parsons, A. D.; Pedder, D. J.

    1988-06-01

    Imaging thermal detector technology is a rapidly advancing field in which the current emphasis is towards the development of very large arrays of very small pyroelectric detector elements. For maximum responsivity, each of the thin pyroelectric elements in an array must be provided with a thermal absorber to convert incoming infrared radiation into heat. This paper describes one such absorber structure, comprising a thin metal film, impedance matched to free space, and a quarter-wave polymer film which offers an acceptably low thermal mass. The structure and properties of this thin-film absorber are compared with those of an electroplated platinum black absorber commonly used in thermal detectors. The theory of the absorber is presented and good agreement is shown between calculated and experimentally derived absorption spectra.

  16. Energy Deposition and Radiological Studies for the LBNF Hadron Absorber

    SciTech Connect

    Rakhno, I. L.; Mokhov, N. V.; Tropin, I. S.; Eidelman, Y. I.

    2015-06-25

    Results of detailed Monte Carlo energy deposition and radiological studies performed for the LBNF hadron absorber with the MARS15 code are described. The model of the entire facility, that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system – all with corresponding radiation shielding – was developed using the recently implemented ROOT-based geometry option in the MARS15 code. Both normal operation and accidental conditions were studied. Results of detailed thermal calculations with the ANSYS code helped to select the most viable design options.

  17. Tech Transfer Webinar: Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2016-07-12

    A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  18. Lightweight Energy Absorbers for Blast Containers

    NASA Technical Reports Server (NTRS)

    Balles, Donald L.; Ingram, Thomas M.; Novak, Howard L.; Schricker, Albert F.

    2003-01-01

    Kinetic-energy-absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.

  19. Design and Manufacture of Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2016-07-12

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  20. Tech Transfer Webinar: Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-06-17

    A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  1. Design and Manufacture of Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-05-28

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  2. Flat solar energy collector with low heat contact between absorber and edge of collector

    SciTech Connect

    Hussmann, E.

    1981-10-27

    The present invention relates to a flat, gas-tight solar energy collector having a novel absorber means consisting of an absorber plate and an edge connecting means attached thereto for connecting the absorber to the edge structure of the collector. No direct thermal contact exists between the edge of the absorber plate and the edge structure means. Thus, heat losses on the sides of the collector are kept to a minimum.

  3. Load limiting energy absorbing lightweight debris catcher

    NASA Technical Reports Server (NTRS)

    Kahn, Jon B. (Inventor); Schneider, William C. (Inventor)

    1991-01-01

    In the representative embodiment of the invention disclosed, a load limiting, energy absorbing net is arranged to overlay a normally-covered vent opening in the rear bulkhead of the space orbiter vehicle. Spatially-disposed flexible retainer straps are extended from the net and respectively secured to bulkhead brackets spaced around the vent opening. The intermediate portions of the straps are doubled over and stitched together in a pattern enabling the doubled-over portions to progressively separate at a predicable load designed to be well below the tensile capability of the straps as the stitches are successively torn apart by the forces imposed on the retainer members whenever the cover plate is explosively separated from the bulkhead and propelled into the net. By arranging these stitches to be successively torn away at a load below the strap strength in response to forces acting on the retainers that are less than the combined strength of the retainers, this tearing action serves as a predictable compact energy absorber for safely halting the cover plate as the retainers are extended as the net is deployed. The invention further includes a block of an energy-absorbing material positioned in the net for receiving loose debris produced by the explosive release of the cover plate.

  4. Thermally tunable water-substrate broadband metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Pang, Yongqiang; Wang, Jiafu; Cheng, Qiang; Xia, Song; Zhou, Xiao Yang; Xu, Zhuo; Cui, Tie Jun; Qu, Shaobo

    2017-03-01

    The naturally occurring water has frequency dispersive permittivity at microwave frequencies and thus is a promising constituent material for broadband absorbers. Here, we develop water as the dielectric spacer in the substrate of metal-backed metamaterial (MM) absorbers. The designed substrate is a hybrid of water and a low-permittivity dielectric material. Such a design allows tight packaging of water and easy fabrication of the absorber. We obtain broadband absorption at temperatures of interest by designing the hybrid substrate and MM inclusions. Additionally, the absorption performance of the water-substrate MM absorbers could be tunable according to the environment temperature. We experimentally demonstrate the broadband and thermally tunable absorption performance. We expect that water could replace dielectric layers in other structural MM absorbers to achieve the broadband and thermally tunable absorption performance.

  5. Energy harvesting from an autoparametric vibration absorber

    NASA Astrophysics Data System (ADS)

    Yan, Zhimiao; Hajj, Muhammad R.

    2015-11-01

    The combined control and energy harvesting characteristics of an autoparametric vibration absorber consisting of a base structure subjected to the external force and a cantilever beam with a tip mass are investigated. The piezoelectric sheets are attached to the cantilever beam to convert the vibrations of the base structure into electrical energy. The coupled nonlinear representative model is developed by using the extended Hamiton’s principle. The effects of the electrical load resistance on the frequency and damping ratio of the cantilever beam are analyzed. The impacts of the external force and load resistance on the structural displacements of the base structure and the beam and on the level of harvested energy are determined. The results show that the initial conditions have a significant impact on the system’s response. The relatively high level of energy harvesting is not necessarily accompanied with the minimum displacements of the base structure.

  6. Method and apparatus for determining the content and distribution of a thermal neutron absorbing material in an object

    DOEpatents

    Crane, Thomas W.

    1986-01-01

    The disclosure is directed to an apparatus and method for determining the content and distribution of a thermal neutron absorbing material within an object. Neutrons having an energy higher than thermal neutrons are generated and thermalized. The thermal neutrons are detected and counted. The object is placed between the neutron generator and the neutron detector. The reduction in the neutron flux corresponds to the amount of thermal neutron absorbing material in the object. The object is advanced past the neutron generator and neutron detector to obtain neutron flux data for each segment of the object. The object may comprise a space reactor heat pipe and the thermal neutron absorbing material may comprise lithium.

  7. Method and apparatus for determining the content and distribution of a thermal neutron absorbing material in an object

    DOEpatents

    Crane, T.W.

    1983-12-21

    The disclosure is directed to an apparatus and method for determining the content and distribution of a thermal neutron absorbing material within an object. Neutrons having an energy higher than thermal neutrons are generated and thermalized. The thermal neutrons are detected and counted. The object is placed between the neutron generator and the neutron detector. The reduction in the neutron flux corresponds to the amount of thermal neutron absorbing material in the object. The object is advanced past the neutron generator and neutron detector to obtain neutron flux data for each segment of the object. The object may comprise a space reactor heat pipe and the thermal neutron absorbing material may comprise lithium.

  8. Electronic and thermally tunable infrared metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Shrekenhamer, David; Miragliotta, Joseph A.; Brinkley, Matthew; Fan, Kebin; Peng, Fenglin; Montoya, John A.; Gauza, Sebastian; Wu, Shin-Tson; Padilla, Willie J.

    2016-09-01

    In this paper, we report a computational and experimental study using tunable infrared (IR) metamaterial absorbers (MMAs) to demonstrate frequency tunable (7%) and amplitude modulation (61%) designs. The dynamic tuning of each structure was achieved through the addition of an active material—liquid crystals (LC) or vanadium dioxide (VO2)-within the unit cell of the MMA architecture. In both systems, an applied stimulus (electric field or temperature) induced a dielectric change in the active material and subsequent variation in the absorption and reflection properties of the MMA in the mid- to long-wavelength region of the IR (MWIR and LWIR, respectively). These changes were observed to be reversible for both systems and dynamic in the LC-based structure.

  9. Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

    SciTech Connect

    Guddala, Sriram Kumar, Raghwendra; Ramakrishna, S. Anantha

    2015-03-16

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm{sup 2}.

  10. Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

    NASA Astrophysics Data System (ADS)

    Guddala, Sriram; Kumar, Raghwendra; Ramakrishna, S. Anantha

    2015-03-01

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm2.

  11. An Energy Absorber for the International Space Station

    NASA Technical Reports Server (NTRS)

    Wilkes, Bob; Laurence, Lora

    2000-01-01

    The energy absorber described herein is similar in size and shape to an automotive shock absorber, requiring a constant, high load to compress over the stroke, and self-resetting with a small load. The differences in these loads over the stroke represent the energy absorbed by the device, which is dissipated as friction. This paper describes the evolution of the energy absorber, presents the results of testing performed, and shows the sensitivity of this device to several key design variables.

  12. Wave energy extraction by coupled resonant absorbers.

    PubMed

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.

  13. Thermal analysis of the crotch absorber in APS

    NASA Astrophysics Data System (ADS)

    Sheng, I. C. A.; Howell, Joseph W.

    1993-02-01

    A crotch absorber design for use in the Advanced Photon Source (APS) has been proposed and analyzed. The absorber is placed downstream of sectors S2 and S4 in the curved storage ring chamber and is subjected to a peak power of 120 W/mm2 per 100 mA synchrotron radiation. A beryllium ring is brazed on the GlidCop cooling cylinder in order to diffuse the concentrated bending magnet heating. One concentric water channel and two annular return water channels are arranged in the GlidCop cylinder to enhance the cooling. A Bodner-Partom thermoviscoplastic constitutive equation and a modified Manson-Coffin fatigue relation are proposed to simulate the cyclic thermal loading, as well as to predict the thermal fatigue life of the crotch absorber. Results of temperature and stress using finite element computations are displayed and a series of e-beam welder tests and microstructure measurements are reported.

  14. Thermal analysis of the crotch absorber in APS

    SciTech Connect

    Sheng, I.C.; Howell, J.

    1992-01-01

    A crotch absorber design for use in the Advanced Photon source (APS) has been proposed and analyzed. the absorber is placed downstream of sectors S2 and S4 in the curved storage ring chamber and will be subjected to a peak power of 120 W/mm{sup 2} per 100mA synchrotron radiation. A beryllium ring is brazed on the GlidCop cooling cylinder in order to diffuse the concentrated bending magnet heating. One concentric water channel and two annular return water channels are arranged in the GlidCop cylinder to enhance the cooling. A Bodner-Partom thermoviscoplastic constitutive equation and a modified Manson-Coffin fatigue relation are proposed to simulate the cyclic thermal loading, as well as to predict the thermal fatigue life of the crotch absorber. Results of temperature and stress using finite element computations are displayed and series of e-beam welder tests and microstructure measurements are reported.

  15. Thermal analysis of the crotch absorber in APS

    SciTech Connect

    Sheng, I.C.; Howell, J.

    1992-10-01

    A crotch absorber design for use in the Advanced Photon source (APS) has been proposed and analyzed. the absorber is placed downstream of sectors S2 and S4 in the curved storage ring chamber and will be subjected to a peak power of 120 W/mm{sup 2} per 100mA synchrotron radiation. A beryllium ring is brazed on the GlidCop cooling cylinder in order to diffuse the concentrated bending magnet heating. One concentric water channel and two annular return water channels are arranged in the GlidCop cylinder to enhance the cooling. A Bodner-Partom thermoviscoplastic constitutive equation and a modified Manson-Coffin fatigue relation are proposed to simulate the cyclic thermal loading, as well as to predict the thermal fatigue life of the crotch absorber. Results of temperature and stress using finite element computations are displayed and series of e-beam welder tests and microstructure measurements are reported.

  16. Absorbed dose rates in tissue from prompt gamma emissions from near-thermal neutron absorption

    DOE PAGES

    Schwahn, Scott O.

    2015-10-01

    Prompt gamma emission data from the International Atomic Energy Agency s Prompt Gamma-ray Neutron Activation Analysis database are analyzed to determine the absorbed dose rates in tissue to be expected when natural elements are exposed in a near-thermal neutron environment.

  17. HEATS: Thermal Energy Storage

    SciTech Connect

    2012-01-01

    HEATS Project: The 15 projects that make up ARPA-E’s HEATS program, short for “High Energy Advanced Thermal Storage,” seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.

  18. Thermal energy transformer

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.; Thiele, C. L. (Inventor)

    1979-01-01

    For use in combination with a heat engine, a thermal energy transformer is presented. It is comprised of a flux receiver having a first wall defining therein a radiation absorption cavity for converting solar flux to thermal energy, and a second wall defining an energy transfer wall for the heat engine. There is a heat pipe chamber interposed between the first and second walls having a working fluid disposed within the chamber and a wick lining the chamber for conducting the working fluid from the second wall to the first wall. Thermal energy is transferred from the radiation absorption cavity to the heat engine.

  19. Thermal energy storage

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.; Picklesimer, E. A.

    1978-01-01

    The general scope of study on thermal energy storage development includes: (1) survey and review possible concepts for storing thermal energy; (2) evaluate the potentials of the surveyed concepts for practical applications in the low and high temperature ranges for thermal control and storage, with particular emphasis on the low temperature range, and designate the most promising concepts; and (3) determine the nature of further studies required to expeditiously convert the most promising concept(s) to practical applications. Cryogenic temperature control by means of energy storage materials was also included.

  20. Thermal radiation absorbed by dairy cows in pasture.

    PubMed

    da Silva, Roberto Gomes; Guilhermino, Magda Maria; de Morais, Débora Andréia E Façanha

    2010-01-01

    The goal of the present paper was to assess a method for estimating the thermal radiation absorbed by dairy cows (0.875 Holstein-0.125 Guzerath) on pasture. A field test was conducted with 472 crossbred dairy cows in three locations of a tropical region. The following environmental data were collected: air temperature, partial vapour pressure, wind speed, black globe temperature, ground surface temperature and solar radiation. Average total radiation absorbed by animals was calculated as R(abs) = 640.0 +/- 3.1 W .m(-2). Absorbed short-wave radiation (solar direct, diffuse and reflected) averaged 297.9 +/- 2.7 W m(-2); long wave (from the sky and from terrestrial surfaces) averaged 342.1 +/- 1.5 W m(-2). It was suggested that a new environmental measurement, the effective radiant heat load (ERHL), could be used to assess the effective mean radiant temperature (T*(mr)). Average T*(mr) was 101.4 +/- 1.2 degrees C, in contrast to the usual mean radiant temperature, T(mr) = 65.1 +/- 0.5 degrees C. Estimates of T*(mr) were considered as more reliable than those of T (mr) in evaluating the thermal environment in the open field, because T (mr) is almost totally associated only with long wave radiation.

  1. Reprint of : Thermoelectricity without absorbing energy from the heat sources

    NASA Astrophysics Data System (ADS)

    Whitney, Robert S.; Sánchez, Rafael; Haupt, Federica; Splettstoesser, Janine

    2016-08-01

    We analyze the power output of a quantum dot machine coupled to two electronic reservoirs via thermoelectric contacts, and to two thermal reservoirs - one hot and one cold. This machine is a nanoscale analogue of a conventional thermocouple heat-engine, in which the active region being heated is unavoidably also exchanging heat with its cold environment. Heat exchange between the dot and the thermal reservoirs is treated as a capacitive coupling to electronic fluctuations in localized levels, modeled as two additional quantum dots. The resulting multiple-dot setup is described using a master equation approach. We observe an "exotic" power generation, which remains finite even when the heat absorbed from the thermal reservoirs is zero (in other words the heat coming from the hot reservoir all escapes into the cold environment). This effect can be understood in terms of a non-local effect in which the heat flow from heat source to the cold environment generates power via a mechanism which we refer to as Coulomb heat drag. It relies on the fact that there is no relaxation in the quantum dot system, so electrons within it have a non-thermal energy distribution. More poetically, one can say that we find a spatial separation of the first-law of thermodynamics (heat to work conversion) from the second-law of thermodynamics (generation of entropy). We present circumstances in which this non-thermal system can generate more power than any conventional macroscopic thermocouple (with local thermalization), even when the latter works with Carnot efficiency.

  2. Thermal energy storage

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The planning and implementation of activities associated with lead center management role and the technical accomplishments pertaining to high temperature thermal energy storage subsystems are described. Major elements reported are: (1) program definition and assessment; (2) research and technology development; (3) industrial storage applications; (4) solar thermal power storage applications; and (5) building heating and cooling applications.

  3. Thermal Treatment Improvement of CuSbS2 Absorbers

    SciTech Connect

    de Souza Lucas, Francisco Willian; Welch, Adam W.; Baranowski, Lauryn L.; Dippo, Patricia C.; Mascaro, Lucia H.; Zakutayev, Andriy

    2015-06-14

    Thermal treatment in Sb2S3 vapor was used to improve the quality of CuSbS2 thin films, a promising non-toxic and earth-abundant absorber. A change in the CuSbS2 crystallographic texture and a decrease in the lattice stress were observed, as well as increases in the grain size, photoluminescence intensity and photoconductivity. To eliminate the influence of the possible Sb2S3 rich surface layer on photovoltaic performance, a selective chemical etching with KOH was developed.

  4. Thermally Resilient, Broadband Optical Absorber from UV to IR Derived from Carbon Nanostructures

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Coles, James B.

    2012-01-01

    Optical absorber coatings have been developed from carbon-based paints, metal blacks, or glassy carbon. However, such materials are not truly black and have poor absorption characteristics at longer wavelengths. The blackness of such coatings is important to increase the accuracy of calibration targets used in radiometric imaging spectrometers since blackbody cavities are prohibitively large in size. Such coatings are also useful potentially for thermal detectors, where a broadband absorber is desired. Au-black has been a commonly used broadband optical absorber, but it is very fragile and can easily be damaged by heat and mechanical vibration. An optically efficient, thermally rugged absorber could also be beneficial for thermal solar cell applications for energy harnessing, particularly in the 350-2,500 nm spectral window. It has been demonstrated that arrays of vertically oriented carbon nanotubes (CNTs), specifically multi-walled-carbon- nanotubes (MWCNTs), are an exceptional optical absorber over a broad range of wavelengths well into the infrared (IR). The reflectance of such arrays is 100x lower compared to conventional black materials, such as Au black in the spectral window of 350-2,500 nm. Total hemispherical measurements revealed a reflectance of approximately equal to 1.7% at lambda approximately equal to 1 micrometer, and at longer wavelengths into the infrared (IR), the specular reflectance was approximately equal to 2.4% at lambda approximately equal to 7 micrometers. The previously synthesized CNTs for optical absorber applications were formed using water-assisted thermal chemical vapor deposition (CVD), which yields CNT lengths in excess of 100's of microns. Vertical alignment, deemed to be a critical feature in enabling the high optical absorption from CNT arrays, occurs primarily via the crowding effect with thermal CVD synthesized CNTs, which is generally not effective in aligning CNTs with lengths less than 10 m. Here it has been shown that the

  5. Ocean Thermal Energy.

    ERIC Educational Resources Information Center

    Berkovsky, Boris

    1987-01-01

    Describes Ocean Thermal Energy Conservation (OTEC) as a method for exploiting the temperature difference between warm surface waters of the sea and its cold depths. Argues for full-scale demonstrations of the technique for producing energy for coastal regions. (TW)

  6. Ocean thermal energy conversion

    SciTech Connect

    Avery, W.H.

    1983-03-17

    A brief explanation of the Ocean Thermal Energy Conversion (OTEC) concept and an estimate of the amount of energy that can be produced from the ocean resource without introducing environmental concerns are presented. Use of the OTEC system to generate electric power and products which can replace fossil fuels is shown. The OTEC program status and its prospects for the future are discussed.

  7. Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector

    NASA Astrophysics Data System (ADS)

    Li, Qiyuan; Zheng, Cheng; Mesgari, Sara; Hewakuruppu, Yasitha L.; Hjerrild, Natasha; Crisostomo, Felipe; Morrison, Karl; Woffenden, Albert; Rosengarten, Gary; Scott, Jason A.; Taylor, Robert A.

    2015-12-01

    Recent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (<100 °C) [4] or higher temperature (>100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (<10 cm height) solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 +/- 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal

  8. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of-the-art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments, and or heavy phase change material heat exchangers for thermal storage. These approaches can lead to large loss of water and a significant mass penalties for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. This paper describes analysis models to predict performance and optimize the size of the SEAR system, estimated size and mass of key components, and an assessment of potential mass savings compared with alternative thermal management approaches. We also describe a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  9. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of the- art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments. This approach can lead to large loss of water and a significant mass penalty for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. The optimal system is based on a trade-off between the mass of water saved and extra power needed to regenerate the LiCl absorber. This paper describes analysis models and the predicted performance and optimize the size of the SEAR system, estimated size and mass of key components, and power requirements for regeneration. We also present a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  10. Delayed-feedback vibration absorbers to enhance energy harvesting

    NASA Astrophysics Data System (ADS)

    Kammer, Ayhan S.; Olgac, Nejat

    2016-02-01

    Recovering energy from ambient vibrations has recently been a popular research topic. This article is conceived as a concept study that explores new directions to enhance the performance of such energy harvesting devices from base excitation. The main idea revolves around the introduction of delayed feedback sensitization (or tuning) of an active vibration absorber setup. To clarify the concept, the Delayed Resonator theory is reviewed and its suitability for energy harvesting purposes is studied. It is recognized that an actively tuned and purely resonant absorber is infeasible for such applications. The focus is then shifted to alternative tuning schemes that deviate from resonance conditions. Also called Delayed Feedback Vibration Absorbers, these devices may indeed provide significant enhancements in energy harvesting capacity. Analytical developments are presented to study energy generation and consumption characteristics. Effects of excitation frequency and absorber damping are investigated. The influences of time-delayed feedback on the stability and the transient performance of the system are also treated. The analysis starts from a stand-alone absorber, emulating seismic mass type harvesters. The work is then extended to vibration control applications, where an absorber/harvester is coupled with a primary structure. The results are demonstrated with numerical simulations on a case study.

  11. Solar thermal energy receiver

    NASA Technical Reports Server (NTRS)

    Baker, Karl W. (Inventor); Dustin, Miles O. (Inventor)

    1992-01-01

    A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity.

  12. Improving impact resistance of ceramic materials by energy absorbing surface layers

    NASA Technical Reports Server (NTRS)

    Kirchner, H. P.; Seretsky, J.

    1974-01-01

    Energy absorbing surface layers were used to improve the impact resistance of silicon nitride and silicon carbide ceramics. Low elastic modulus materials were used. In some cases, the low elastic modulus was achieved using materials that form localized microcracks as a result of thermal expansion anisotropy, thermal expansion differences between phases, or phase transformations. In other cases, semi-vitreous or vitreous materials were used. Substantial improvements in impact resistance were observed at room and elevated temperatures.

  13. Multiobjective Topology Optimization of Energy Absorbing Materials

    DTIC Science & Technology

    2015-08-01

    overlapping function. This data structure is tree-shaped and so genetic programming is used as the optimizer. The forward problem is solved with a...strain energy. Results demonstrate the efficacy of the proposed algorithm. 15. SUBJECT TERMS topology optimization; Pareto optimization; genetic ...combined using an overlapping function. This data structure is tree-shaped and so genetic programming is used as the optimizer. The forward problem

  14. Phase-Change Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    1989-11-01

    The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100 C in low-temperature troughs to over 1500 C in dish and central receiver systems.

  15. Article for thermal energy storage

    DOEpatents

    Salyer, Ival O.

    2000-06-27

    A thermal energy storage composition is provided which is in the form of a gel. The composition includes a phase change material and silica particles, where the phase change material may comprise a linear alkyl hydrocarbon, water/urea, or water. The thermal energy storage composition has a high thermal conductivity, high thermal energy storage, and may be used in a variety of applications such as in thermal shipping containers and gel packs.

  16. Energy absorber for sodium-heated heat exchanger

    DOEpatents

    Essebaggers, J.

    1975-12-01

    A heat exchanger is described in which water-carrying tubes are heated by liquid sodium and in which the results of accidental contact between the water and the sodium caused by failure of one or more of the water tubes is minimized. An energy absorbing chamber contains a compressible gas and is connected to the body of flowing sodium by a channel so that, in the event of a sodium-water reaction, products of the reaction will partially fill the energy absorbing chamber to attenuate the rise in pressure within the heat exchanger.

  17. Energy-harvesting shock absorber with a mechanical motion rectifier

    NASA Astrophysics Data System (ADS)

    Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George

    2013-02-01

    Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges.

  18. Unglazed transpired solar collector having a low thermal-conductance absorber

    DOEpatents

    Christensen, Craig B.; Kutscher, Charles F.; Gawlik, Keith M.

    1997-01-01

    An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprising an unglazed absorber formed of low thermal-conductance material having a front surface for receiving the solar radiation and openings in the unglazed absorber for passage of the incoming air such that the incoming air is heated as it passes towards the front surface of the absorber and the heated air passes through the openings in the absorber for distribution.

  19. Unglazed transpired solar collector having a low thermal-conductance absorber

    DOEpatents

    Christensen, C.B.; Kutscher, C.F.; Gawlik, K.M.

    1997-12-02

    An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprises an unglazed absorber formed of low thermal-conductance material having a front surface for receiving the solar radiation and openings in the unglazed absorber for passage of the incoming air such that the incoming air is heated as it passes towards the front surface of the absorber and the heated air passes through the openings in the absorber for distribution. 3 figs.

  20. Thermal Energy Conversion Branch

    NASA Technical Reports Server (NTRS)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  1. Aquifer thermal energy storage program

    NASA Technical Reports Server (NTRS)

    Fox, K.

    1980-01-01

    The purpose of the Aquifer Thermal Energy Storage Demonstration Program is to stimulate the interest of industry by demonstrating the feasibility of using a geological formation for seasonal thermal energy storage, thereby, reducing crude oil consumption, minimizing thermal pollution, and significantly reducing utility capital investments required to account for peak power requirements. This purpose will be served if several diverse projects can be operated which will demonstrate the technical, economic, environmental, and institutional feasibility of aquifer thermal energy storage systems.

  2. A novel self-locked energy absorbing system

    NASA Astrophysics Data System (ADS)

    Chen, Yuli; Qiao, Chuan; Qiu, Xinming; Zhao, Shougen; Zhen, Cairu; Liu, Bin

    2016-02-01

    Metallic thin-walled round tubes are widely used as energy absorption elements. However, lateral splash of the round tubes under impact loadings reduces the energy absorption efficiency and may cause secondary damage. Therefore, it is necessary to assemble and fasten round tubes together by boundary constraints and/or fasteners between tubes, which increases the time and labor cost and affects the mechanical performance of round tubes. In an effort to break through this limitation, a novel self-locked energy-absorbing system has been proposed in this paper. The proposed system is made up of thin-walled tubes with dumbbell-shaped cross section, which are specially designed to interlock with each other and thus provide lateral constraint under impact loadings. Both finite element simulations and impact experiment demonstrated that without boundary constraints or fasteners between tubes, the proposed self-locked energy-absorbing system can still effectively attenuate impact loads while the round tube systems fail to carry load due to the lateral splashing of tubes. Furthermore, the geometric design for a single dumbbell-shaped tube and the stacking arrangement for the system are discussed, and a general guideline on the structural design of the proposed self-locked energy absorbing system is provided.

  3. Structural and optical properties of copper-coated substrates for solar thermal absorbers

    NASA Astrophysics Data System (ADS)

    Pratesi, Stefano; De Lucia, Maurizio; Meucci, Marco; Sani, Elisa

    2016-10-01

    Spectral selectivity, i.e. merging a high absorbance at sunlight wavelengths to a low emittance at the wavelengths of thermal spectrum, is a key characteristics for materials to be used for solar thermal receivers. It is known that spectrally selective absorbers can raise the receiver efficiency for all solar thermal technologies. Tubular sunlight receivers for parabolic trough collector (PTC) systems can be improved by the use of spectrally selective coatings. Their absorbance is increased by deposing black films, while the thermal emittance is minimized by the use of properly-prepared substrates. In this work we describe the intermediate step in the fabrication of black-chrome coated solar absorbers, namely the fabrication and characterization of copper coatings on previously nickel-plated stainless steel substrates. We investigate the copper surface features and optical properties, correlating them to the coating thickness and to the deposition process, in the perspective to assess optimal conditions for solar absorber applications.

  4. Energy Absorbing Seat System for an Agricultural Aircraft

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Jones, Lisa E. (Technical Monitor)

    2002-01-01

    A task was initiated to improve the energy absorption capability of an existing aircraft seat through cost-effective retrofitting, while keeping seat-weight increase to a minimum. This task was undertaken as an extension of NASA ongoing safety research and commitment to general aviation customer needs. Only vertical crash scenarios have been considered in this task which required the energy absorbing system to protect the seat occupant in a range of crash speeds up to 31 ft/sec. It was anticipated that, the forward and/or side crash accelerations could be attenuated with the aid of airbags, the technology of which is currently available in automobiles and military helicopters. Steps which were followed include, preliminary crush load determination, conceptual design of cost effective energy absorbers, fabrication and testing (static and dynamic) of energy absorbers, system analysis, design and fabrication of dummy seat/rail assembly, dynamic testing of dummy seat/rail assembly, and finally, testing of actual modified seat system with a dummy occupant. A total of ten full scale tests have been performed including three of the actual aircraft seat. Results from full-scale tests indicated that occupant loads were attenuated successfully to survivable levels.

  5. Energy scavenging strain absorber: application to kinetic dielectric elastomer generator

    NASA Astrophysics Data System (ADS)

    Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.

    2014-03-01

    Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

  6. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-09-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor.

  7. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    PubMed Central

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-01-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor. PMID:25200005

  8. A universal electromagnetic energy conversion adapter based on a metamaterial absorber.

    PubMed

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D; Simons, Rainee N; Chen, Yunpeng; Xiao, John Q

    2014-09-09

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor.

  9. Enhancing radiative energy transfer through thermal extraction

    NASA Astrophysics Data System (ADS)

    Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

    2016-06-01

    Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

  10. Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

    SciTech Connect

    Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S.; Rakhno, I.; /Fermilab

    2012-05-10

    A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.

  11. Thermal energy storage test facility

    NASA Technical Reports Server (NTRS)

    Ternes, M. P.

    1980-01-01

    The thermal behavior of prototype thermal energy storage units (TES) in both heating and cooling modes is determined. Improved and advanced storage systems are developed and performance standards are proposed. The design and construction of a thermal cycling facility for determining the thermal behavior of full scale TES units is described. The facility has the capability for testing with both liquid and air heat transport, at variable heat input/extraction rates, over a temperature range of 0 to 280 F.

  12. Crash-Energy Absorbing Composite Structure and Method of Fabrication

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris (Inventor); Carden, Huey D. (Inventor)

    1998-01-01

    A stand-alone, crash-energy absorbing structure and fabrication method are provided. A plurality of adjoining rigid cells are each constructed of resin-cured fiber reinforcement and are arranged in a geometric configuration. The geometric configuration of cells is integrated by means of continuous fibers wrapped thereabout in order to maintain the cells in the geometric configuration. The cured part results in a net shape, stable structure that can function on its own with no additional reinforcement and can withstand combined loading while crushing in a desired direction.

  13. Water absorbance and thermal properties of sulfated wheat gluten films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat gluten films of varying thicknesses formed at 30C to 70C were treated with cold sulfuric acid to produce sulfated gluten films. Chemical, thermal, thermal stability, and water uptake properties were characterized for neat and sulfated films. The sulfated gluten films were able ...

  14. Ocean Thermal Extractable Energy Visualization

    SciTech Connect

    Ascari, Matthew

    2012-10-28

    The Ocean Thermal Extractable Energy Visualization (OTEEV) project focuses on assessing the Maximum Practicably Extractable Energy (MPEE) from the world’s ocean thermal resources. MPEE is defined as being sustainable and technically feasible, given today’s state-of-the-art ocean energy technology. Under this project the OTEEV team developed a comprehensive Geospatial Information System (GIS) dataset and software tool, and used the tool to provide a meaningful assessment of MPEE from the global and domestic U.S. ocean thermal resources.

  15. Energy-absorbing-beam design for composite aircraft subfloors

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Kellas, Sotiris

    1993-01-01

    Data have been presented from the design support testing of composite energy absorbing (EA) aircraft subfloor structures. The focus of the current study is the design and testing of subfloor structural concepts that would limit the loads transmitted to occupants to less than 20 g at crush speeds of approximately 30 fps. The EA composite subfloor is being designed to replace an existing noncrashworthy metallic subfloor in a composite aircraft prior to a full-scale crash test. A sandwich spar construction of a sine wave beam was chosen for evaluation and was found to have excellent energy absorbing characteristics. The design objective of obtaining sustained crushing loads of the spar between 200-300 lbf/inch were achieved for potentially limiting occupants loads to around 20 g's. Stroke efficiency of up to 79 percent of the initial spar height under desired sustained crushing loads was obtained which is far greater than the level provided by metal structure. Additionally, a substantial residual spar stiffness was retained after impact, and the flange integrity, which is critical for seat retention, was maintained after crushing of the spars.

  16. Material Model Evaluation of a Composite Honeycomb Energy Absorber

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Annett, Martin S.; Fasanella, Edwin L.; Polanco, Michael A.

    2012-01-01

    A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of three DEA components were simulated using the nonlinear, explicit transient dynamic code, LS-DYNA . In addition, a full-scale crash test of an MD-500 helicopter, retrofitted with DEA blocks, was simulated. The four material models used to represent the DEA included: *MAT_CRUSHABLE_FOAM (Mat 63), *MAT_HONEYCOMB (Mat 26), *MAT_SIMPLIFIED_RUBBER/FOAM (Mat 181), and *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM (Mat 142). Test-analysis calibration metrics included simple percentage error comparisons of initial peak acceleration, sustained crush stress, and peak compaction acceleration of the DEA components. In addition, the Roadside Safety Verification and Validation Program (RSVVP) was used to assess similarities and differences between the experimental and analytical curves for the full-scale crash test.

  17. Energy absorption of refractory absorber with periodic nanostructures

    NASA Astrophysics Data System (ADS)

    Kang, Yuchen; Yang, Shuhan; Wang, Yanhong; Wu, Jingzhi

    2016-10-01

    Refractory material with surface plasmonic structures have the function of spectrum selective absorption and radiation spectrum regulation. In this paper, we design an absorber with periodic cylindrical nanostructures and a dielectric layer of Al2O3 based on the substrate of metal Tantalum (Ta). The energy absorption characteristics of the absorber have been simulated and analyzed by changing various constructional parameters. The simulation results indicate that structural parameters have great influence on the spectrum absorption in the range of wavelength 400-4000nm. The period and radius of nanostructure have a important effect on the absorption peaks in the infrared region. Infrared absorption peak can reach more than 99% and produce a red shift due to parameters changing. At the whole visible field, the absorption enhancement effect is significant. The refractive index and thickness of dielectric layer also have an obviously effect on the absorption spectrum. Furthermore, it is also obviously that thickness of dielectric layer has enhancement effect on absorption of infrared spectrum. The research found that the absorption and radiation spectrum of surface plasmonic materials can be effectively controlled by combining the high temperature radiation characteristics of high temperature metal. Thermophotovoltaic system can provide a kind of new methods and ideas for improving conversion efficiency, energy saving and consumption reducing.

  18. Ocean Thermal Energy Conversion (OTEC)

    NASA Technical Reports Server (NTRS)

    Lavi, A.

    1977-01-01

    Energy Research and Development Administration research progress in Ocean Thermal Energy Conversion (OTEC) is outlined. The development program is being focused on cost effective heat exchangers; ammonia is generally used as the heat exchange fluid. Projected costs for energy production by OTEC vary between $1000 to $1700 per kW.

  19. Lih thermal energy storage device

    DOEpatents

    Olszewski, Mitchell; Morris, David G.

    1994-01-01

    A thermal energy storage device for use in a pulsed power supply to store waste heat produced in a high-power burst operation utilizes lithium hydride as the phase change thermal energy storage material. The device includes an outer container encapsulating the lithium hydride and an inner container supporting a hydrogen sorbing sponge material such as activated carbon. The inner container is in communication with the interior of the outer container to receive hydrogen dissociated from the lithium hydride at elevated temperatures.

  20. Study of thermal effects and optical properties of an innovative absorber in integrated collector storage solar water heater

    NASA Astrophysics Data System (ADS)

    Taheri, Yaser; Alimardani, Kazem; Ziapour, Behrooz M.

    2015-10-01

    Solar passive water heaters are potential candidates for enhanced heat transfer. Solar water heaters with an integrated water tank and with the low temperature energy resource are used as the simplest and cheapest recipient devices of the solar energy for heating and supplying hot water in the buildings. The solar thermal performances of one primitive absorber were determined by using both the experimental and the simulation model of it. All materials applied for absorber such as the cover glass, the black colored sands and the V shaped galvanized plate were submerged into the water. The water storage tank was manufactured from galvanized sheet of 0.0015 m in thickness and the effective area of the collector was 0.67 m2. The absorber was installed on a compact solar water heater. The constructed flat-plate collectors were tested outdoors. However the simulation results showed that the absorbers operated near to the gray materials and all experimental results showed that the thermal efficiencies of the collector are over than 70 %.

  1. Theoretical and thermal characterization of a wideband perfect absorber for application in solar cells

    NASA Astrophysics Data System (ADS)

    Rufangura, Patrick; Sabah, Cumali

    2016-12-01

    This paper suggests a metamaterial (MTM) absorber structure to be used for efficiency improved solar cell. The proposed MTM absorber consists of the topmost three concentric circular ring resonators, and a ground metal plane sandwiched to the top layer with a dielectric spacer. Numerical simulation and theoretical (interference theory) studies on the proposed design show a wideband with near-perfect (>99%) absorption response in the visible frequency region of the solar spectrum. Thermal characterization of the suggested design is also conducted in order to investigate its absorption capability at different temperatures. The proposed MTM absorber design is believed to be an outstanding candidate toward high-efficiency solar photovoltaic cell.

  2. Thermal mechanisms of laser marking in transparent polymers with light-absorbing microparticles

    NASA Astrophysics Data System (ADS)

    Zelenska, K. S.; Zelensky, S. E.; Poperenko, L. V.; Kanev, K.; Mizeikis, V.; Gnatyuk, V. A.

    2016-01-01

    Interaction of highly viscous polystyrene suspensions of light-absorbing microparticles with pulsed radiation of a Q-switched YAG:Nd3+ laser is investigated. Absorption of laser radiation by the suspended microparticles causes thermal decomposition (pyrolysis) of the polymer in the vicinity of the overheated particles. Laser-induced incandescence (LII) of light-absorbing microparticles under irradiation by a sequence of laser pulses is observed. The mechanism of laser marking includes formation of light-absorbing and scattering centers by accumulation of carbonaceous and gaseous products of pyrolysis.

  3. Seasonal Thermal Energy Storage Program

    NASA Technical Reports Server (NTRS)

    Minor, J. E.

    1980-01-01

    The Seasonal Thermal Energy Storage (STES) Program designed to demonstrate the storage and retrieval of energy on a seasonal basis using heat or cold available from waste or other sources during a surplus period is described. Factors considered include reduction of peak period demand and electric utility load problems and establishment of favorable economics for district heating and cooling systems for commercialization of the technology. The initial thrust of the STES Program toward utilization of ground water systems (aquifers) for thermal energy storage is emphasized.

  4. Prompt-gamma detection towards absorbed energy monitoring during hadrontherapy

    SciTech Connect

    Krimmer, J.; Balleyguier, L.; Dauvergne, D.; Mathez, H.; Pinto, M.; Testa, E.; Zoccarato, Y.; Herault, J.; Amblard, R.; Angellier, G.

    2015-07-01

    Hadrontherapy is an emerging technique which exploits the fact that a large quantity of the energy of the incident particles is deposited at the end of their flight path. This allows a conformation of the applied dose to the tumor volume and a simultaneous sparing of surrounding healthy tissue. A real-time control of the ion range during the treatment is possible via the detection of prompt secondary radiation (gamma rays or charged particles). Besides a monitoring of the ion range, the knowledge of the total energy absorbed inside the patient is also of importance for an improvement of the treatment quality. It has been shown that the ambient dose in a treatment room is correlated to the monitoring units, i.e. the number of protons of the beam delivery system. The present study consists in applying time-of-flight (TOF) information to identify prompt gamma-rays generated by interactions inside the patient which provides a direct information on the energy imparted. Results from test measurements will be given, which show that events generated in the nozzle and the target phantom can be discriminated. Furthermore, a standalone detection system is being developed which will be read out by a standard PC. The status of the developments for the corresponding electronics will be presented. (authors)

  5. Thermal and optical analysis of selective absorber coatings based on soot for applications in solar cookers

    NASA Astrophysics Data System (ADS)

    Servín, H.; Peña, M.; Sobral, H.; González, M.

    2017-01-01

    The thermal and optical properties of selective absorber coatings of a solar cooker have been investigated. Coatings have been prepared using soot from pine resin, wood stove and sugarcane, previously separated by size. Results show that the cooking power and the overall efficiency of these pots are higher than others painted with black primer. Besides, by using an integrating sphere, the diffuse reflectance of absorbers has been obtained. Lower values of the reflectance have been measured for the pots covered with soot, showing a high correlation with the results achieved from the thermal tests, considering the measurement errors.

  6. Thermal Energy Storage: Fourth Annual Review Meeting

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The development of low cost thermal energy storage technologies is discussed in terms of near term oil savings, solar energy applications, and dispersed energy systems for energy conservation policies. Program definition and assessment and research and technology development are considered along with industrial storage, solar thermal power storage, building heating and cooling, and seasonal thermal storage. A bibliography on seasonal thermal energy storage emphasizing aquifer thermal energy is included.

  7. Thermal energy storage and transport

    NASA Technical Reports Server (NTRS)

    Hausz, W.

    1980-01-01

    The extraction of thermal energy from large LWR and coal fired plants for long distance transport to industrial and residential/commercial users is analyzed. Transport of thermal energy as high temperature water is shown to be considerably cheaper than transport as steam, hot oil, or molten salt over a wide temperature range. The delivered heat is competitive with user-generated heat from oil, coal, or electrode boilers at distances well over 50 km when the pipeline operates at high capacity factor. Results indicate that thermal energy storage makes meeting of even very low capacity factor heat demands economic and feasible and gives the utility flexibility to meet coincident electricity and heat demands effectively.

  8. Thermal tuning of infrared resonant absorbers based on hybrid gold-VO{sub 2} nanostructures

    SciTech Connect

    Kocer, Hasan; Butun, Serkan; Aydin, Koray; Banar, Berker; Wang, Kevin; Wu, Junqiao; Tongay, Sefaatttin

    2015-04-20

    Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO{sub 2}) nanostructure arrays. Absorption intensity is tuned from 90% to 20% and 96% to 32% using hybrid gold-VO{sub 2} nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO{sub 2} (68 °C). Phase change materials such as VO{sub 2} deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity.

  9. Thermal tuning of infrared resonant absorbers based on hybrid gold-VO2 nanostructures

    NASA Astrophysics Data System (ADS)

    Kocer, Hasan; Butun, Serkan; Banar, Berker; Wang, Kevin; Tongay, Sefaatttin; Wu, Junqiao; Aydin, Koray

    2015-04-01

    Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO2) nanostructure arrays. Absorption intensity is tuned from 90% to 20% and 96% to 32% using hybrid gold-VO2 nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO2 (68 °C). Phase change materials such as VO2 deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity.

  10. Infrared broadband metasurface absorber for reducing the thermal mass of a microbolometer.

    PubMed

    Jung, Joo-Yun; Song, Kyungjun; Choi, Jun-Hyuk; Lee, Jihye; Choi, Dae-Geun; Jeong, Jun-Ho; Neikirk, Dean P

    2017-03-27

    We demonstrate an infrared broadband metasurface absorber that is suitable for increasing the response speed of a microbolometer by reducing its thermal mass. A large fraction of holes are made in a periodic pattern on a thin lossy metal layer characterised with a non-dispersive effective surface impedance. This can be used as a non-resonant metasurface that can be integrated with a Salisbury screen absorber to construct an absorbing membrane for a microbolometer that can significantly reduce the thermal mass while maintaining high infrared broadband absorption in the long wavelength infrared (LWIR) band. The non-dispersive effective surface impedance can be matched to the free space by optimising the surface resistance of the thin lossy metal layer depending on the size of the patterned holes by using a dc approximation method. In experiments a high broadband absorption was maintained even when the fill factor of the absorbing area was reduced to 28% (hole area: 72%), and it was theoretically maintained even when the fill factor of the absorbing area was reduced to 19% (hole area: 81%). Therefore, a metasurface with a non-dispersive effective surface impedance is a promising solution for reducing the thermal mass of infrared microbolometer pixels.

  11. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    PubMed Central

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  12. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    PubMed

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-06

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

  13. Measurement of photochemical quenching of absorbed quanta in photosystem I of intact leaves using simultaneous measurements of absorbance changes at 830 nm and thermal dissipation.

    PubMed

    Bukhov, Nikolai G; Carpentier, Robert

    2003-02-01

    The relationship between the redox state of the photosystem (PS) I primary donor, P700, and thermal energy dissipation in PSI were examined in intact leaves using simultaneous measurements of absorbance changes at 830 nm and variations of thermal emission monitored by photoacoustic (PA) spectroscopy, respectively. A strict proportionality (close to a 1:1 ratio) was found between the magnitudes of P700 oxidation and a positive variable PA signal induced by far-red light of various irradiances under conditions favoring effective electron donation from PSII to PSI. The proportionality was observed also between the ratio of reduced P700 to the total P700 content and the ratio of the variable component to the total PA signal measured with modulated light of 695 nm. Those findings clearly revealed that in intact leaves, variable thermal dissipation in PSI is determined by the fraction of P700 in the reduced state. Diuron-treated leaves exposed to 45 degrees C in which PSI received electrons not from PSII, but from soluble reductants localized in the chloroplast stroma were also used. In such leaves, the linear relationship between the ratio of reduced P700 to the total P700 content and the ratio of the variable component to the total PA signal measured with modulated light of 700 nm has been found as well, but its slope was twice smaller than in untreated leaves. This is probably related to an increased contribution of thermal emission from inactive PSII to the steady-state level of the PA signal in diuron-treated leaves exposed to high temperatures. The results demonstrated that the yield of variable thermal dissipation is strictly dependent on the redox pressure applied to the photosystem. The above illustrates the strong photochemical energy quenching occurring when the reaction centers are in open state (reduced P700).

  14. Phase-change thermal energy storage: Final subcontract report

    SciTech Connect

    Not Available

    1989-11-01

    The research and development described in this document was conducted within the US Department of Energy's Solar Thermal Technology Program. The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100{degree}C in low-temperature troughs to over 1500{degree}C in dish and central receiver systems. 12 refs., 119 figs., 4 tabs.

  15. Anti-terrorist vehicle crash impact energy absorbing barrier

    DOEpatents

    Swahlan, David J.

    1989-01-01

    An anti-terrorist vehicle crash barrier includes side support structures, crushable energy absorbing aluminum honeycomb modules, and an elongated impact-resistant beam extending between, and at its opposite ends through vertical guideways defined by, the side support structures. An actuating mechanism supports the beam at its opposite ends for movement between a lowered barrier-withdrawn position in which a traffic-supporting side of the beam is aligned with a traffic-bearing surface permitting vehicular traffic between the side support structures and over the beam, and a raised barrier-imposed position in which the beam is aligned with horizontal guideways defined in the side support structures above the traffic-bearing surface, providing an obstruction to vehicular traffic between the side support structures. The beam is movable rearwardly in the horizontal guideways with its opposite ends disposed transversely therethrough upon being impacted at its forward side by an incoming vehicle. The crushable modules are replaceably disposed in the horizontal guideways between aft ends thereof and the beam. The beam, replaceable modules, side support structures and actuating mechanism are separate and detached from one another such that the beam and replaceable modules are capable of coacting to disable and stop an incoming vehicle without causing structural damage to the side support structures and actuating mechanism.

  16. Anti-terrorist vehicle crash impact energy absorbing barrier

    SciTech Connect

    Swahlan, D.J.

    1989-04-18

    An anti-terrorist vehicle crash barrier includes side support structures, crushable energy absorbing aluminum honeycomb modules, and an elongated impact-resistant beam extending between, and at its opposite ends through vertical guideways defined by, the side support structures. An actuating mechanism supports the beam at its opposite ends for movement between a lowered barrier-withdrawn position in which a traffic-supporting side of the beam is aligned with a traffic-bearing surface permitting vehicular traffic between the side support structures and over the beam, and a raised barrier-imposed position in which the beam is aligned with horizontal guideways defined in the side support structures above the traffic-bearing surface, providing an obstruction to vehicular traffic between the side support structures. The beam is movable rearwardly in the horizontal guideways with its opposite ends disposed transversely therethrough upon being impacted at its forward side by an incoming vehicle. The crushable modules are replaceably disposed in the horizontal guideways between aft ends thereof and the beam. The beam, replaceable modules, side support structures and actuating mechanism are separate and detached from one another such that the beam and replaceable modules are capable of coacting to disable and stop an incoming vehicle without causing structural damage to the side support structures and actuating mechanism. 6 figs.

  17. Nonlinear modeling of magnetorheological energy absorbers under impact conditions

    NASA Astrophysics Data System (ADS)

    Mao, Min; Hu, Wei; Choi, Young-Tai; Wereley, Norman M.; Browne, Alan L.; Ulicny, John; Johnson, Nancy

    2013-11-01

    Magnetorheological energy absorbers (MREAs) provide adaptive vibration and shock mitigation capabilities to accommodate varying payloads, vibration spectra, and shock pulses, as well as other environmental factors. A key performance metric is the dynamic range, which is defined as the ratio of the force at maximum field to the force in the absence of field. The off-state force is typically assumed to increase linearly with speed, but at the higher shaft speeds occurring in impact events, the off-state damping exhibits nonlinear velocity squared damping effects. To improve understanding of MREA behavior under high-speed impact conditions, this study focuses on nonlinear MREA models that can more accurately predict MREA dynamic behavior for nominal impact speeds of up to 6 m s-1. Three models were examined in this study. First, a nonlinear Bingham-plastic (BP) model incorporating Darcy friction and fluid inertia (Unsteady-BP) was formulated where the force is proportional to the velocity. Second, a Bingham-plastic model incorporating minor loss factors and fluid inertia (Unsteady-BPM) to better account for high-speed behavior was formulated. Third, a hydromechanical (HM) analysis was developed to account for fluid compressibility and inertia as well as minor loss factors. These models were validated using drop test data obtained using the drop tower facility at GM R&D Center for nominal drop speeds of up to 6 m s-1.

  18. Ocean thermal energy conversion (OTEC)

    SciTech Connect

    Lockerby, R.W.

    1981-01-01

    Ocean thermal energy conversion (OTEC) is reviewed briefly. The two types of OTEC system (open and closed) are described and limitations are pointed out. A bibliography of 148 references on OTEC is given for the time period 1975 to 1980. Entries are arranged alphabetically according to the author's name. (MJJ)

  19. Semi-transparent solar energy thermal storage device

    DOEpatents

    McClelland, John F.

    1985-06-18

    A visually transmitting solar energy absorbing thermal storage module includes a thermal storage liquid containment chamber defined by an interior solar absorber panel, an exterior transparent panel having a heat mirror surface substantially covering the exterior surface thereof and associated top, bottom and side walls, Evaporation of the thermal storage liquid is controlled by a low vapor pressure liquid layer that floats on and seals the top surface of the liquid. Porous filter plugs are placed in filler holes of the module. An algicide and a chelating compound are added to the liquid to control biological and chemical activity while retaining visual clarity. A plurality of modules may be supported in stacked relation by a support frame to form a thermal storage wall structure.

  20. Semi-transparent solar energy thermal storage device

    DOEpatents

    McClelland, John F.

    1986-04-08

    A visually transmitting solar energy absorbing thermal storage module includes a thermal storage liquid containment chamber defined by an interior solar absorber panel, an exterior transparent panel having a heat mirror surface substantially covering the exterior surface thereof and associated top, bottom and side walls. Evaporation of the thermal storage liquid is controlled by a low vapor pressure liquid layer that floats on and seals the top surface of the liquid. Porous filter plugs are placed in filler holes of the module. An algicide and a chelating compound are added to the liquid to control biological and chemical activity while retaining visual clarity. A plurality of modules may be supported in stacked relation by a support frame to form a thermal storage wall structure.

  1. Determination of the optical and the thermal properties of an absorbing medium by using infrared thermometry

    NASA Astrophysics Data System (ADS)

    Yang, Seung-Jin; Baek, Jun-Hyeok; Kim, Seung-Eun; Kwon, Min-Ki; Park, Jong-Rak; Yeom, Dong-Il; Kim, Ji-Sun; Baek, Jin-Young; Kim, Hyung-Sik; Jun, Jae-Hoon; Chung, Soon-Cheol

    2016-12-01

    Spatiotemporal changes in the surface temperature of an absorbing medium irradiated by using 532-nm laser pulses were measured using an infrared camera. Relevant numerical simulations of the heat transfer equation were performed. The simulations showed that the maximum temperature increase was linearly proportional to the absorption coefficient with no dependence on the thermal conductivity and that the decay time constant depended on both the absorption coefficient and the thermal conductivity. The absorption coefficient and the thermal conductivity of the medium were determined by fitting the simulated results for the maximum temperature increase and decay time constant to the measured results.

  2. CPCs with segmented absorbers

    SciTech Connect

    Keita, M.; Robertson, H.S. )

    1991-01-01

    One of the most promising means of improving the performance of solar thermal collectors is to reduce the energy lost by the hot absorber. One way to do this, not currently part of the technology, is to recognize that since the absorber is usually not irradiated uniformly, it is therefore possible to construct an absorber of thermally isolated segments, circulate the fluid in sequence from low to high irradiance segments, and reduce loss by improving effective concentration. This procedure works even for ideal concentrators, without violating Winston's theorem. Two equivalent CPC collectors with single and segmented absorber were constructed and compared under actual operating conditions. The results showed that the daily thermal efficiency of the collector with segmented absorber is higher (about 13%) than that of the collector with nonsegmented absorber.

  3. Thermal energy storage devices, systems, and thermal energy storage device monitoring methods

    DOEpatents

    Tugurlan, Maria; Tuffner, Francis K; Chassin, David P.

    2016-09-13

    Thermal energy storage devices, systems, and thermal energy storage device monitoring methods are described. According to one aspect, a thermal energy storage device includes a reservoir configured to hold a thermal energy storage medium, a temperature control system configured to adjust a temperature of the thermal energy storage medium, and a state observation system configured to provide information regarding an energy state of the thermal energy storage device at a plurality of different moments in time.

  4. Solar Thermal Energy Storage in a Photochromic Macrocycle.

    PubMed

    Vlasceanu, Alexandru; Broman, Søren L; Hansen, Anne S; Skov, Anders B; Cacciarini, Martina; Kadziola, Anders; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2016-07-25

    The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA-DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF-VHF). A stepwise energy release over two sequential ring-closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long-term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release.

  5. Antireflection treatment of thickness sensitive spectrally selective (TSSS) paints for thermal solar absorbers

    SciTech Connect

    Lundh, M.; Waeckelgaard, E.; Blom, T.

    2010-01-15

    There are several methods to produce solar absorbers, and one cheap alternative is painted absorbers, preferably painted with a spectrally selective paint. The optical properties of Thickness Sensitive Spectrally Selective (TSSS) paints are, however, limited by the thickness of the paint layer. In this study it is shown that the solar absorptance of two commercial TSSS paints can be increased between 0.01 and 0.02 units with an antireflection treatment using a silicon dioxide layer deposited from silica-gel. It was found that the thermal emittance (100 C) did not change significantly after the treatment. (author)

  6. Triplet-triplet energy transfer from a UV-A absorber butylmethoxydibenzoylmethane to UV-B absorbers.

    PubMed

    Kikuchi, Azusa; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Yagi, Mikio

    2014-01-01

    The phosphorescence decay of a UV-A absorber, 4-tert-butyl-4'-methoxydibenzolymethane (BMDBM) has been observed following a 355 nm laser excitation in the absence and presence of UV-B absorbers, 2-ethylhexyl 4-methoxycinnamate (octyl methoxycinnamate, OMC) and octocrylene (OCR) in ethanol at 77 K. The lifetime of the lowest excited triplet (T1) state of BMDBM is significantly reduced in the presence of OMC and OCR. The observed quenching of BMDBM triplet by OMC and OCR suggests that the intermolecular triplet-triplet energy transfer occurs from BMDBM to OMC and OCR. The T1 state of OCR is nonphosphorescent or very weakly phosphorescent. However, we have shown that the energy level of the T1 state of OCR is lower than that of the enol form of BMDBM. Our methodology of energy-donor phosphorescence decay measurements can be applied to the study of the triplet-triplet energy transfer between UV absorbers even if the energy acceptor is nonphosphorescent. In addition, the delayed fluorescence of BMDBM due to triplet-triplet annihilation was observed in the BMDBM-OMC and BMDBM-OCR mixtures in ethanol at 77 K. Delayed fluorescence is one of the deactivation processes of the excited states of BMDBM under our experimental conditions.

  7. Thermal energy storage program description

    SciTech Connect

    Reimers, E.

    1989-03-01

    The U.S. Department of Energy (DOE) has sponsored applied research, development, and demonstration of technologies aimed at reducing energy consumption and encouraging replacement of premium fuels (notably oil) with renewable or abundant indigenous fuels. One of the technologies identified as being able to contribute to these goals is thermal energy storage (TES). Based on the potential for TES to contribute to the historic mission of the DOE and to address emerging energy issues related to the environment, a program to develop specific TES technologies for diurnal, industrial, and seasonal applications is underway. Currently, the program is directed toward three major application targets: (1) TES development for efficient off-peak building heating and cooling, (2) development of advanced TES building materials, and (3) TES development to reduce industrial energy consumption.

  8. Experimental evaluation of a stationary spherical reflector tracking absorber solar energy collector

    NASA Technical Reports Server (NTRS)

    Steward, W. G.; Kreider, J. F.; Caruso, P. S., Jr.; Kreith, F.

    1976-01-01

    This article presents experimental data for the thermal performance of a stationary, spherical-reflector, tracking-absorber solar energy collector (SRTA). The principle of operation and details of thermal performance of such an SRTA have previously been described. These experimental results were compared with the predictions of a thermal analysis previously published. Experimental results were compared with the prediction of Kreider's computer model. Within the range of the temperature of the experiments, the predicted performance of the unit agreed well with experimental data collected under clear sky conditions. In addition, the extrapolation of the efficiency to higher temperature is shown so that the potential of an SRTA solar collector as a means of providing high temperature steam to operate an electric power facility or for process heat can be evaluated. As a result of the tests conducted by NASA, and an economic analysis not yet publicly available, it appears that the SRTA solar collector concept will be economically viable in competition with any other existing solar system in providing electrical energy.

  9. Moving body velocity arresting line. [stainless steel cables with energy absorbing sleeves

    NASA Technical Reports Server (NTRS)

    Hull, R. A. (Inventor)

    1981-01-01

    The arresting of a moving body is improved through the use of steel cables that elongate to absorb the kinetic energy of the body. A sleeve surrounds the cables, protecting them from chafing and providing a failsafe energy absorbing system should the cables fail.

  10. Nano-Textured Fiber Coatings for Energy Absorbing Polymer Matrix Composite Materials

    DTIC Science & Technology

    2004-12-01

    NANO-TEXTURED FIBER COATINGS FOR ENERGY ABSORBING POLYMER MATRIX COMPOSITE MATERIALS R. E. Jensen and S. H. McKnight Army Research Laboratory...Textured Fiber Coatings For Energy Absorbing Polymer Matrix Composite Materials 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  11. Microwavable thermal energy storage material

    DOEpatents

    Salyer, I.O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments. 3 figs.

  12. Microwavable thermal energy storage material

    DOEpatents

    Salyer, Ival O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene-vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments.

  13. Thermal energy storage flight experiments

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1989-01-01

    Consideration is given to the development of an experimental program to study heat transfer, energy storage, fluid movement, and void location under microgravity. Plans for experimental flight packages containing Thermal Energy Storage (TES) material applicable for advanced solar heat receivers are discussed. Candidate materials for TES include fluoride salts, salt eutectics, silicides, and metals. The development of a three-dimensional computer program to describe TES material behavior undergoing melting and freezing under microgravity is also discussed. The TES experiment concept and plans for ground and flight tests are outlined.

  14. Sound-absorbing slabs and structures based on granular materials (bound and unbound). [energy absorbing efficiency of porous material

    NASA Technical Reports Server (NTRS)

    Petre-Lazar, S.; Popeea, G.

    1974-01-01

    Sound absorbing slabs and structures made up of bound or unbound granular materials are considered and how to manufacture these elements at the building site. The raw material is a single grain powder (sand, expanded blast furnace slag, etc.) that imparts to the end products an apparent porosity of 25-45% and an energy dissipation within the structure leading to absorption coefficients that can be compared with those of mineral wool and urethane.

  15. More Efficient Solar Thermal-Energy Receiver

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.

    1987-01-01

    Thermal stresses and reradiation reduced. Improved design for solar thermal-energy receiver overcomes three major deficiencies of solar dynamic receivers described in literature. Concentrator and receiver part of solar-thermal-energy system. Receiver divided into radiation section and storage section. Concentrated solar radiation falls on boiling ends of heat pipes, which transmit heat to thermal-energy-storage medium. Receiver used in number of applications to produce thermal energy directly for use or to store thermal energy for subsequent use in heat engine.

  16. Reducing heat loss from the energy absorber of a solar collector

    DOEpatents

    Chao, Bei Tse; Rabl, Ari

    1976-01-01

    A device is provided for reducing convective heat loss in a cylindrical radiant energy collector. It includes a curved reflective wall in the shape of the arc of a circle positioned on the opposite side of the exit aperture from the reflective side walls of the collector. Radiant energy exiting the exit aperture is directed by the curved wall onto an energy absorber such that the portion of the absorber upon which the energy is directed faces downward to reduce convective heat loss from the absorber.

  17. Impact resistance of fiber composites - Energy-absorbing mechanisms and environmental effects

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Sinclair, J. H.

    1985-01-01

    Energy absorbing mechanisms were identified by several approaches. The energy absorbing mechanisms considered are those in unidirectional composite beams subjected to impact. The approaches used include: mechanic models, statistical models, transient finite element analysis, and simple beam theory. Predicted results are correlated with experimental data from Charpy impact tests. The environmental effects on impact resistance are evaluated. Working definitions for energy absorbing and energy releasing mechanisms are proposed and a dynamic fracture progression is outlined. Possible generalizations to angle-plied laminates are described.

  18. Impact resistance of fiber composites: Energy absorbing mechanisms and environmental effects

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Sinclair, J. H.

    1983-01-01

    Energy absorbing mechanisms were identified by several approaches. The energy absorbing mechanisms considered are those in unidirectional composite beams subjected to impact. The approaches used include: mechanic models, statistical models, transient finite element analysis, and simple beam theory. Predicted results are correlated with experimental data from Charpy impact tests. The environmental effects on impact resistance are evaluated. Working definitions for energy absorbing and energy releasing mechanisms are proposed and a dynamic fracture progression is outlined. Possible generalizations to angle-plied laminates are described.

  19. Energy from ocean thermal gradients

    NASA Astrophysics Data System (ADS)

    Cohen, R.

    1980-02-01

    Ocean Thermal Energy Conversion (OTEC) transforms the solar heating of the ocean surface into electrical energy, either transmitting it to shore or using it to manufacture energy-intensive products such as aluminum, ammonia, hydrogen or magnesium at sea. Open-cycle systems, requiring extremely large turbines and degasifiers, are not thought to be as advanced as closed-cycle systems which use heat exchangers (either shell-and-tube or plate) that are made of titanium, stainless steel or aluminum alloys, which must minimize corrosion and biofouling, and that use ammonia, propane or fluorocarbons as working fluids. OTEC platform configurations include ship shapes and submersibles, such as spar buoys, and require cold-water pipes 1,000 m long, made of such materials as elastomers, lightweight concrete and fiberglass-reinforced plastic.

  20. Thermal preparation of chitosan-acrylic acid superabsorbent: optimization, characteristic and water absorbency.

    PubMed

    Ge, Huacai; Wang, Senkang

    2014-11-26

    Chitosan-acrylic acid superabsorbent polymer was successfully prepared by the thermal reaction without using initiator and crosslinker in air. The effects of some reaction variables on the water absorbency of this polymer were investigated by orthogonal tests, and the optimal conditions were described. The influences of temperature, time, ratio of the reactants and neutralization degree of acrylic acid on the reaction were further studied. These polymers were also prepared in nitrogen atmosphere and by using a radical initiator and compared against thermal reaction obtained polymers. The structures of the polymers were characterized by FT-IR, TGA, XRD, (13)C NMR and elemental analyses. The results showed that the thermal reaction product of acrylic acid with chitosan might form N-carboxyethyl grafted and amide-linked polymer and this product could absorb water 644 times its own dry weight. The possible mechanism for the thermal reaction was further suggested. The purpose of this research was to explore the friendly synthesized method of the superabsorbent.

  1. Ocean thermal-energy conversion

    NASA Astrophysics Data System (ADS)

    Ford, G.; Niblett, C.; Walker, L.

    1983-03-01

    The principles underlying ocean thermal-energy conversion (OTEC) are reviewed, and a schematic layout of a system is included. The two systems currently under study, the open system and the closed system, are described. The prospect now, it is noted, is that OTEC plants will not be commercially viable on a widespread basis, even in the tropics. This is especially true of the large-scale plants that have been envisioned. A strong possibility is seen, however, that smaller plants, generating about 40 megawatts of electrical power, can survive commercially. The following conditions would favor their success: placement on land rather than at sea; placement in areas (such as islands) where alternative energy supplies are at a premium; and designing the plant to operate in conjunction with either an aquaculture or a desalination plant.

  2. Optimisation of dynamic vibration absorbers to minimise kinetic energy and maximise internal power dissipation

    NASA Astrophysics Data System (ADS)

    Zilletti, Michele; Elliott, Stephen J.; Rustighi, Emiliano

    2012-08-01

    The tuning of a dynamic vibration absorber is considered such that either the kinetic energy of the host structure is minimised or the power dissipation within the absorber is maximised. If the host structure is approximated as a damped single degree of freedom, the optimal values for the ratio of the absorber's natural frequency to the host structure and the optimal damping ratio of the absorber are shown to be the same whether the kinetic energy of the host structure is minimised or the power dissipation of the absorber is maximised. It is also demonstrated that the total power input into the system does not depend on the two parameters but only on the host structure's mass.

  3. Development of 2 underseat energy absorbers for application to crashworthy passenger seats for general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Warrick, J. C.; Desjardins, S. P.

    1979-01-01

    This report presents the methodology and results of a program conducted to develop two underseat energy absorber (E/A) concepts for application to nonadjustable crashworthy passenger seats for general aviation aircraft. One concept utilizes an inflated air bag, and the other, a convoluted sheet metal bellows. Prototypes of both were designed, built, and tested. Both concepts demonstrated the necessary features of an energy absorber (load-limiter); however, the air bag concept is particularly encouraging because of its light weight. Several seat frame concepts also were investigated as a means of resisting longitudinal and lateral loads and of guiding the primary vertical stroke of the underseat energy absorber. Further development of a seat system design using the underseat energy absorbers is recommended because they provide greatly enhanced crash survivability as compared with existing general aviation aircraft seats.

  4. Energy deposition through radiative processes in absorbers irradiated by electron beams

    NASA Astrophysics Data System (ADS)

    Tatsuo, Tabata; Pedro, Andreo; Kunihiko, Shinoda; Rinsuke, Ito

    1994-09-01

    The component of energy deposition due to radiative processes (bremsstrahlung component) in absorbers irradiated by electron beams has been computed together with the total energy deposition by using the ITS Monte Carlo system version 3.0. Plane-parallel electron beams with energies from 0.1 to 100 MeV have been assumed to be incident normally on the slab absorber, whose thickness is 2.5 times the continuous slowing-down approximation (csda) range of the incident electrons. Absorber materials considered are elemental solids with atomic numbers between 4 and 92 (Be, C, Al, Cu, Ag, Au and U). An analytic formula is given to express the depth profile of the bremsstrahlung component as a function of scaled depth (depth in units of the csda range), incident-electron energy and absorber atomic number. It is also applicable to compounds.

  5. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

    SciTech Connect

    Dubey, P. K. Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-15

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  6. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target.

    PubMed

    Dubey, P K; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  7. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

    NASA Astrophysics Data System (ADS)

    Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  8. Solar energy thermally powered electrical generating system

    NASA Technical Reports Server (NTRS)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  9. Soft Landing of Spacecraft on Energy-Absorbing Self-Deployable Cushions

    NASA Technical Reports Server (NTRS)

    Sokolowski, Witold

    2003-01-01

    A report proposes the use of cold hibernated elastic memory (CHEM) foam structures to cushion impacts of small (1 to 50 kg) exploratory spacecraft on remote planets. Airbags, which are used on larger (800 to 1,000 kg) spacecraft have been found to (1) be too complex for smaller spacecraft; (2) provide insufficient thermal insulation between spacecraft and ground; (3) bounce on impact, thereby making it difficult to land spacecraft in precisely designated positions; and (4) be too unstable to serve as platforms for scientific observations. A CHEM foam pad according to the proposal would have a glass-transition temperature (Tg) well above ambient temperature. It would be compacted, at a temperature above Tg, to about a tenth or less of its original volume, then cooled below Tg, then installed on a spacecraft without compacting restraints. Upon entry of the spacecraft into a planetary atmosphere, the temperature would rise above Tg, causing the pad to expand to its original volume and shape. As the spacecraft decelerated and cooled, the temperature would fall below Tg, rigidifying the foam structure. The structure would absorb kinetic energy during ground impact by inelastic crushing, thus protecting the payload from damaging shocks. Thereafter, this pad would serve as a mechanically stable, thermally insulating platform for the landed spacecraft.

  10. Thermal Energy Harvesting from Wildlife

    NASA Astrophysics Data System (ADS)

    Woias, P.; Schule, F.; Bäumke, E.; Mehne, P.; Kroener, M.

    2014-11-01

    In this paper we present the measurement of temperature differences between the ambient air and the body temperature of a sheep (Heidschnucke) and its applicability for thermoelectric energy harvesting from livestock, demonstrated via the test of a specially tailored TEG system in a real-life experiment. In three measurement campaigns average temperature differences were found between 2.5 K and 3.5 K. Analytical models and FEM simulations were carried out to determine the actual thermal resistance of the sheep's fur from comparisons with the temperature measurements. With these data a thermoelectric (TEG) generator was built in a thermally optimized housing with adapted heats sink. The whole TEG system was mounted to a collar, including a data logger for recording temperature and TEG voltage. First measurements at the neck of a sheep were accomplished, with a calculated maximal average power output of 173 μW at the TEG. Taking the necessity of a low-voltage step-up converter into account, an electric output power of 54 μW is available which comes close to the power consumption of a low-power VHF tracking system.

  11. Thermal energy management process experiment

    NASA Technical Reports Server (NTRS)

    Ollendorf, S.

    1984-01-01

    The thermal energy management processes experiment (TEMP) will demonstrate that through the use of two-phase flow technology, thermal systems can be significantly enhanced by increasing heat transport capabilities at reduced power consumption while operating within narrow temperature limits. It has been noted that such phenomena as excess fluid puddling, priming, stratification, and surface tension effects all tend to mask the performance of two-phase flow systems in a 1-g field. The flight experiment approach would be to attack the experiment to an appropriate mounting surface with a 15 to 20 meter effective length and provide a heat input and output station in the form of heaters and a radiator. Using environmental data, the size, location, and orientation of the experiment can be optimized. The approach would be to provide a self-contained panel and mount it to the STEP through a frame. A small electronics package would be developed to interface with the STEP avionics for command and data handling. During the flight, heaters on the evaporator will be exercised to determine performance. Flight data will be evaluated against the ground tests to determine any anomalous behavior.

  12. Solar energy thermalization and storage device

    DOEpatents

    McClelland, J.F.

    A passive solar thermalization and thermal energy storage assembly which is visually transparent is described. The assembly consists of two substantial parallel, transparent wall members mounted in a rectangular support frame to form a liquid-tight chamber. A semitransparent thermalization plate is located in the chamber, substantially paralled to and about equidistant from the transparent wall members to thermalize solar radiation which is stored in a transparent thermal energy storage liquid which fills the chamber. A number of the devices, as modules, can be stacked together to construct a visually transparent, thermal storage wall for passive solar-heated buildings.

  13. Solar energy thermalization and storage device

    DOEpatents

    McClelland, John F.

    1981-09-01

    A passive solar thermalization and thermal energy storage assembly which is visually transparent. The assembly consists of two substantial parallel, transparent wall members mounted in a rectangular support frame to form a liquid-tight chamber. A semitransparent thermalization plate is located in the chamber, substantially paralled to and about equidistant from the transparent wall members to thermalize solar radiation which is stored in a transparent thermal energy storage liquid which fills the chamber. A number of the devices, as modules, can be stacked together to construct a visually transparent, thermal storage wall for passive solar-heated buildings.

  14. Measurement and Simulation of Thermal Conductivity of Hafnium-Aluminum Thermal Neutron Absorber Material

    NASA Astrophysics Data System (ADS)

    Guillen, Donna Post; Harris, William H.

    2016-09-01

    A metal matrix composite (MMC) material composed of hafnium aluminide (Al3Hf) intermetallic particles in an aluminum matrix has been identified as a promising material for fast flux irradiation testing applications. This material can filter thermal neutrons while simultaneously providing high rates of conductive cooling for experiment capsules. The purpose of this work is to investigate effects of Hf-Al material composition and neutron irradiation on thermophysical properties, which were measured before and after irradiation. When performing differential scanning calorimetry (DSC) on the irradiated specimens, a large exotherm corresponding to material annealment was observed. Therefore, a test procedure was developed to perform DSC and laser flash analysis (LFA) to obtain the specific heat and thermal diffusivity of pre- and post-annealment specimens. This paper presents the thermal properties for three states of the MMC material: (1) unirradiated, (2) as-irradiated, and (3) irradiated and annealed. Microstructure-property relationships were obtained for the thermal conductivity. These relationships are useful for designing components from this material to operate in irradiation environments. The ability of this material to effectively conduct heat as a function of temperature, volume fraction Al3Hf, radiation damage, and annealing is assessed using the MOOSE suite of computational tools.

  15. Harnessing snap-through instability for shape-recoverable energy-absorbing structure

    NASA Astrophysics Data System (ADS)

    Kang, Sung; Shan, Sicong; Raney, Jordan; Wang, Pai; Candido, Francisco; Lewis, Jennifer; Bertoldi, Katia

    2015-03-01

    Energy absorbing materials and structures are used in numerous areas for maintaining structural integrity, protection and comfort. To absorb/dissipate energy from shock/vibration, one generally relies on processes such as plastic deformation and damping as the case of metal foams and suspensions. Because plastic deformation and damping induce irreversible change in the energy-absorbing systems such as shape changes and degradation of damping elements by heat dissipation, it would be desirable to develop a new energy-absorption mechanism with reversibility. Furthermore, it would be desirable to implement energy-absorption mechanisms whose behavior is not affected by the rate of loading. Here, we report a shape-recoverable system that absorbs energy without degradation by harnessing multistability in elastic structures. Using numerical simulations, we investigate geometrical parameters that determine the onset of the snap-through and multi-stability. We subsequently manufacture structures with different geometrical parameters and sizes using a scalable direct-write 3D printing approach. We experimentally demonstrate reversible energy-absorption in these structures at strain rates over three orders of magnitudes, with reduced peak acceleration under impact by up to one order of magnitude compared with control samples. Our findings can open new opportunities for scalable design and manufacturing of energy-absorbing materials and structures.

  16. High-energy thermal synchrotron emission

    NASA Technical Reports Server (NTRS)

    Imamura, J. N.; Epstein, R. I.; Petrosian, V.

    1985-01-01

    It is shown how the thermal synchrotron emission spectrum is modified when the photon energy is greater than the mean energy of the radiating particles. The effect if applying this energy conservation constraint is to produce spectra which have less high-energy photon emission than had been previously estimated. The thermal synchrotron spectra provide satisfactory fits to recently observed very high energy gamma ray spectra of certain burst sources.

  17. A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Shuja, S. Z.

    2017-01-01

    Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

  18. Measurements of the Thermal Neutron Macroscopic Absorption Cross Section for Neutron Absorbing Layers

    NASA Astrophysics Data System (ADS)

    Kiyani, Abouzar; Rostam, G. Gh.; Sadat Kiai, S. M.; Bakhsh, Hossin Jahan; Mahdavi, Farzad

    2011-12-01

    Objective of this study is measuring the macroscopic cross section of a neutron absorbing layer for thermal neutrons. For this purpose a neutron source and BF 3 detector have been applied. For measuring macroscopic cross section of thermal neutrons by the Formula, it is necessary to provide suitable geometric conditions in order to assume the production and build-up coefficient to be the unit value (=1). To fulfill required conditions for this assumption, surface of the detector is covered with a 2 mm thick layer of cadmium. Radiation window of the detector has a 3 cm diameter, situated directly in front of the source. By placing the cadmium cover over the detector, variation of values verses thickness of absorbent layer, renders linear function behavior, making it possible to measure the macroscopic cross section. The next stage is applying the MCNP code by simulating F1 tally and cosine-cards for calculating Total Macroscopic Cross-Section. Validation of this study is achieved through comparison of simulation by the MCNP code and results rendered by experiment measurements.

  19. RF-Thermal-Structural Analysis of a Waveguide Higher Order Mode Absorber

    SciTech Connect

    G. Cheng; E. F. Daly; R. A. Rimmer; M. Stirbet; L. Vogel; H. Wang; K. M. Wilson

    2007-07-03

    For an ongoing high current cryomodule project, a total of 5 higher order mode (HOM) absorbers are required per cavity. The load is designed to absorb Radio Frequency (RF) heat induced by HOMs in a 748.5MHz cavity. Each load is targeted at a 4 kW dissipation capability. Water cooling is employed to remove the heat generated in ceramic tiles and by surface losses on the waveguide walls. A sequentially coupled RF-thermal-structural analysis was developed in ANSYS to optimize the HOM load design. Frequency-dependent dielectric material properties measured from samples and RF power spectrum calculated by the beam-cavity interaction codes were considered. The coupled field analysis capability of ANSYS avoided mapping of results between separate RF and thermal/structural simulation codes. For verification purposes, RF results obtained from ANSYS were compared to those from MAFIA, HFSS, and Microwave Studio. Good agreement was reached and this confirms that multiple-field coupled analysis is a desirable choice in analysis of HOM loads. Similar analysis could be performed on other particle accelerator components where distributed RF heating and surface current induced losses are inevitable.

  20. Thermal energy storage for cogeneration applications

    NASA Astrophysics Data System (ADS)

    Drost, M. K.; Antoniak, Z. I.

    1992-04-01

    Cogeneration is playing an increasingly important role in providing energy efficient power generation and thermal energy for space heating and industrial process heat applications. However, the range of applications for cogeneration could be further increased if the generation of electricity could be decoupled from the generation of process heat. Thermal energy storage (TES) can decouple power generation from the production of process heat, allowing the production of dispatchable power while fully utilizing the thermal energy available from the prime mover. The Pacific Northwest Laboratory (PNL) leads the US Department of Energy's Thermal Energy Storage Program. The program focuses on developing TES for daily cycling (diurnal storage), annual cycling (seasonal storage), and utility applications (utility thermal energy storage (UTES)). Several of these technologies can be used in a cogeneration facility. This paper discusses TES concepts relevant to cogeneration and describes the current status of these TES systems.

  1. Stowable Energy-Absorbing Rocker-Bogie Suspensions

    NASA Technical Reports Server (NTRS)

    Harrington, Brian; Voorhees, Christopher

    2007-01-01

    A report discusses the design of the rocker-bogie suspensions of the Mars Exploration Rover vehicles, which were landed on Mars in January 2004. Going beyond the basic requirements regarding mobility on uneven terrain, the design had to satisfy requirements (1) to enable each suspension to contort so that the rover could be stowed within limited space in a tetrahedral lander prior to deployment and (2) that the suspension be able to absorb appreciable impact loads, with limited deflection, during egress from the lander and traversal of terrain. For stowability, six joints (three on the right, three on the left) were added to the basic rocker-bogie mechanism. One of the joints on each side was a yoke-and-clevis joint at the suspension/differential interface, one was a motorized twist joint in the forward portion of the rocker, and one was a linear joint created by modifying a fixed-length bogie member into a telescoping member. For absorption of impact, the structural members were in the form of box beams made by electron-beam welding of machined, thin-walled, C-channel, titanium components. The box beams were very lightweight and could withstand high bending and torsional loads.

  2. Solar concentrator/absorber

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G. F.

    1976-01-01

    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  3. Microwave impregnation of porous materials with thermal energy storage materials

    SciTech Connect

    Benson, D.K.; Burrows, R.W.

    1991-03-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent tc the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  4. Microwave impregnation of porous materials with thermal energy storage materials

    SciTech Connect

    Benson, D.K.; Burrows, R.W.

    1992-12-31

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  5. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, David K.; Burrows, Richard W.

    1993-01-01

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  6. Microwave impregnation of porous materials with thermal energy storage materials

    DOEpatents

    Benson, D.K.; Burrows, R.W.

    1993-04-13

    A method for impregnating a porous, non-metallic construction material with a solid phase-change material is described. The phase-change material in finely divided form is spread onto the surface of the porous material, after which the porous material is exposed to microwave energy for a time sufficient to melt the phase-change material. The melted material is spontaneously absorbed into the pores of the porous material. A sealing chemical may also be included with the phase-change material (or applied subsequent to the phase-change material) to seal the surface of the porous material. Fire retardant chemicals may also be included with the phase-change materials. The treated construction materials are better able to absorb thermal energy and exhibit increased heat storage capacity.

  7. Energy loss by resonance line photons in an absorbing medium

    NASA Technical Reports Server (NTRS)

    Hummer, D. G.; Kunasz, P. B.

    1980-01-01

    The mean path length of photons undergoing repeated scatterings in media of large optical thickness is calculated from accurate numerical solutions of the transfer equation including the effect of frequency redistribution characteristic of combined Doppler and natural broadening. Energy loss by continuous absorption processes, such as ionization or dust absorption, is discussed, and asymptotic scaling laws for the energy loss, the mean path length, and the mean number of scatterings are inferred from the numerical data.

  8. Thermal energy storage apparatus, controllers and thermal energy storage control methods

    DOEpatents

    Hammerstrom, Donald J.

    2016-05-03

    Thermal energy storage apparatus, controllers and thermal energy storage control methods are described. According to one aspect, a thermal energy storage apparatus controller includes processing circuitry configured to access first information which is indicative of surpluses and deficiencies of electrical energy upon an electrical power system at a plurality of moments in time, access second information which is indicative of temperature of a thermal energy storage medium at a plurality of moments in time, and use the first and second information to control an amount of electrical energy which is utilized by a heating element to heat the thermal energy storage medium at a plurality of moments in time.

  9. Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers: Preprint

    SciTech Connect

    Li, Y.; Yu, Y. H.

    2012-05-01

    During the past few decades, wave energy has received significant attention among all ocean energy formats. Industry has proposed hundreds of prototypes such as an oscillating water column, a point absorber, an overtopping system, and a bottom-hinged system. In particular, many researchers have focused on modeling the floating-point absorber as the technology to extract wave energy. Several modeling methods have been used such as the analytical method, the boundary-integral equation method, the Navier-Stokes equations method, and the empirical method. However, no standardized method has been decided. To assist the development of wave energy conversion technologies, this report reviews the methods for modeling the floating-point absorber.

  10. MCNP simulation of absorbed energy and dose by iodinated contrast agent

    NASA Astrophysics Data System (ADS)

    He, Wenjun; Mah, Eugene; Huda, Walter; Yao, Hai

    2012-03-01

    The purpose of this study is to investigate the absorbed dose and energy by iodinated contrast medium in diagnostic radiology. A simulation geometry in which an inner sphere (d = 0.2cm, 1cm, 5cm) filled with iodinated contrast medium (or water) is located at the center of a 20cm diameter water sphere was used in simulations performed with MCNP5 codes. Monoenergetic x-rays with energies ranging from 40 to 80keV from a cone beam source were utilized and contrast medium concentration ranged from 100 to 1mg/ml. Absorbed dose ratio (RD) to inner sphere and total absorbed energies ratio (RE) to the whole phantom with and without iodinated contrast medium were investigated. The maximum RD was ~13 for the 0.2cm diameter sphere with 100mg/ml contrast medium. The maximum RE was ~1.05 for the 5cm diameter contrast sphere at 80keV with 100mg/ml contrast medium. Under the same incident photon energy, increasing the inner sphere size from 0.2cm to 5cm caused a ~63% increase in the RD on average. Decreasing the contrast medium concentration from 100 to 10 mg/ml caused a decrease of RD of ~ 76%. A conclusion was reached that although local absorbed dose increase caused by iodinated contrast agent could be high; the increase in total absorbed energy is negligible.

  11. Ammonia thermochemical energy transport in a distributed collector solar thermal power plant

    NASA Astrophysics Data System (ADS)

    Williams, O. M.

    1981-01-01

    A thermochemical energy transport system based on ammonia dissociation/synthesis is shown to have potential for reliable cost-effective operation in a distributed collector solar thermal power plant. Liquid ammonia returned to the central plant from a shaded absorber remains inherently separated from the synthesis gas mixture returned from an exposed absorber, enabling the maintenance of a centralized fluid control. Temporal characteristics of the ammonia-based solar thermochemical absorbers are developed by numerical analysis. Sources of energy loss are examined, and it is shown that flow rates to individual absorbers may cover a 12% range of variation without degradation to the overall energy transport efficiency. Operation of the absorber array is examined under conditions of extreme insolation variation due to a scattered cloud cover. The importance of minimizing the absorber thermal capacity is discussed in relation to the available energy required to restore operation after each cloud period. It is shown that the system is relatively immune to large energy losses in this area, compared to the alternative system where both the pipelines and absorbers must be reheated.

  12. Thermal Lens Phenomenon Studied by the Z-Scan Technique: Measurement of the Thermal Conductivity of Highly Absorbing Colloidal Solutions

    NASA Astrophysics Data System (ADS)

    Sehnem, A. L.; Espinosa, D.; Gonçalves, E. S.; Figueiredo Neto, A. M.

    2016-10-01

    We discuss the thermal lens phenomenon in high-absorbing colloidal systems, studied by using the Z-scan technique. The characteristics of the experimental setup to avoid undesirable effects are presented, in particular when pulsed laser beam is used. We show that a cumulative effect may appear in the experiment with chopped laser beams and compromise the results obtained with this technique. This artefact is more significative when colloidal suspensions are investigated. These materials have different characteristic times of heat and mass diffusion, which must be carefully considered to choose the appropriate time interval for the laser pulse and the time between pulses. Two experimental cases with a chopped laser beam, with and without a shutter, are discussed. The sample employed is a magnetic colloidal suspension (a ferrofluid). This sample has magnetic nanoparticles electrically charged in an aqueous solution with free ions and counter ions. Besides the thermal lens effect, charge and mass diffusion may take place when the sample is illuminated by the Gaussian beam, which imposes a thermal gradient on it. The results show that, with the experimental setup without a shutter, the sample does not achieve a complete relaxation between two laser pulses. This generates a measurable cumulative effect after the sample is illuminated during a relatively long period of time. A time modulation with longer time interval between chopped pulses allows the complete relaxation of the sample. This procedure is important for the correct analysis of the thermal lens effect. Reliable values of the thermal conductivity of the sample in different temperatures are obtained and discussed.

  13. Effects of weld damage on the dynamics of energy absorbing lanyards.

    PubMed

    Katona, David N; Bennett, Charlie R; McKoryk, Michael; Brisson, Andre L; Sparrey, Carolyn J

    2017-01-26

    Manufacturers recommend removing fall protection system components from service for any indication of weld spatter or tool damage; however, little is known about the specific effects of lanyard damage on fall arrest dynamics. Thirty-two energy absorbing lanyards were drop tested after being damaged with weld spatter, plasma torches and cutting tools and compared with new, undamaged lanyards. Two lanyards damaged with a plasma torch failed completely without deploying the energy absorber while weld spatter damage and tool cuts, up to 2/3 through the width of the webbing, had no effect on fall arrest dynamics. The results highlight the catastrophic implications of high temperature damage to lanyard webbing resulting from plasma torches - which require immediate removal from service. In addition, the integrated energy absorber design in bungee style lanyards makes them more susceptible to damage anywhere along its length. We therefore recommended against bungee lanyards for ironworkers and welders.

  14. Ultroviolet (UV)- and thermal-stability of absorbing coatings for space instrumentation

    NASA Astrophysics Data System (ADS)

    Weissbrodt, P.; Raupach, L.; Hacker, Erich; Wagner, S.; Kappel, H.

    1994-09-01

    Absorbing coatings for space-borne optical instruments must accept - besides optical requirements - unusual challenges regarding their chemical stability and their emission of gaseous and condensable materials under space conditions. Consideration of mass balances according to ANSI/ASTM E 595 do not provide enough information for proper choice of the coatings in the vicinity of sensitive optical elements. By in-situ mass spectrometric and XPS measurements we have investigated chemical changes of different black paints and inorganic coatings, their outgassing and the contamination of the surfaces near the coatings. In general, organic black paints are threatened by UV- irradiation and by thermal loads. Changes of their chemical composition under energetic UV-irradiation and the intense emission of contaminating materials were proved. The inorganic coatings investigated do not change their chemical composition and cause only comparatively small contamination on surfaces in their vicinity. For reducing the problem of contamination in optical systems it is still necessary to make available appropriate inorganic coatings with improved absorbing characteristics. However, if lower absorption can be tolerated, the use of inorganic coatings in sensible optical equipment should be considered already now.

  15. Multi-Level Experimental and Analytical Evaluation of Two Composite Energy Absorbers

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Littell, Justin D.; Fasanella, Edwin L.; Annett, Martin S.; Seal, Michael D., II

    2015-01-01

    Two composite energy absorbers were developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program. A conical-shaped energy absorber, designated the conusoid, was evaluated that consisted of four layers of hybrid carbon-Kevlar plain weave fabric oriented at [+45 deg/-45 deg/-45 deg/+45 deg] with respect to the vertical, or crush, direction. A sinusoidal-shaped energy absorber, designated the sinusoid, was developed that consisted of hybrid carbon-Kevlar plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical direction and a closed-cell ELFOAM P200 polyisocyanurate (2.0-lb/cu ft) foam core. The design goal for the energy absorbers was to achieve average floor-level accelerations of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in both designs were assessed through dynamic crush testing of component specimens. Once the designs were finalized, subfloor beams of each configuration were fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorbers prior to retrofit into TRACT 2. The retrofitted airframe was crash tested under combined forward and vertical velocity conditions onto soil, which is characterized as a sand/clay mixture. Finite element models were developed of all test articles and simulations were performed using LS-DYNA, a commercial nonlinear explicit transient dynamic finite element code. Test-analysis results are presented for each energy absorber as comparisons of time-history responses, as well as predicted and experimental structural deformations and progressive damage under impact loading for each evaluation level.

  16. Descriptive analysis of aquifer thermal energy storage systems

    SciTech Connect

    Reilly, R.W.

    1980-06-01

    The technical and economic feasibility of large-scale aquifer thermal energy storage (ATES) was examined. A key to ATESs attractiveness is its simplicity of design and construction. The storage device consists of two ordinary water wells drilled into an aquifer, connected at the surface by piping and a heat exchanger. During the storage cycle water is pumped out of the aquifer, through the heat exchanger to absorb thermal energy, and then back down into the aquifer through the second well. The thermal storage remains in the aquifer storage bubble until required for use, when it is recovered by reversing the storage operation. For many applications the installation can probably be designed and constructed using existing site-specific information and modern well-drilling techniques. The potential for cost-effective implementation of ATES was investigated in the Twin Cities District Heating-Cogeneration Study in Minnesota. In the study, ATES demonstrated a net energy saving of 32% over the nonstorage scenario, with an annual energy cost saving of $31 million. Discounting these savings over the life of the project, the authors found that the break-even capital cost for ATES construction was $76/kW thermal, far above the estimated ATES development cost of $23 to 50/kW thermal. It appears tht ATES can be highly cost effective as well as achieve substantial fuel savings. ATES would be environmentally beneficial and could be used in many parts of the USA. The existing body of information on ATES indicates that it is a cost-effective, fuel-conserving technique for providing thermal energy for residential, commercial, and industrial users. The negative aspects are minor and highly site-specific, and do not seem to pose a threat to widespread commercialization. With a suitable institutional framework, ATES promises to supply a substantial portion of the nation's future energy needs. (LCL)

  17. Hybrid energy harvesting using active thermal backplane

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Wook; Lee, Dong-Gun

    2016-04-01

    In this study, we demonstrate the concept of a new hybrid energy harvesting system by combing solar cells with magneto-thermoelectric generator (MTG, i.e., thermal energy harvesting). The silicon solar cell can easily reach high temperature under normal operating conditions. Thus the heated solar cell becomes rapidly less efficient as the temperature of solar cell rises. To increase the efficiency of the solar cell, air or water-based cooling system is used. To surpass conventional cooling devices requiring additional power as well as large working space for air/water collectors, we develop a new technology of pairing an active thermal backplane (ATB) to solar cell. The ATB design is based on MTG technology utilizing the physics of the 2nd order phase transition of active ferromagnetic materials. The MTG is cost-effective conversion of thermal energy to electrical energy and is fundamentally different from Seebeck TEG devices. The ATB (MTG) is in addition to being an energy conversion system, a very good conveyor of heat through both conduction and convection. Therefore, the ATB can provide dual-mode for the proposed hybrid energy harvesting. One is active convective and conductive cooling for heated solar cell. Another is active thermal energy harvesting from heat of solar cell. These novel hybrid energy harvesting device have potentially simultaneous energy conversion capability of solar and thermal energy into electricity. The results presented can be used for better understanding of hybrid energy harvesting system that can be integrated into commercial applications.

  18. Effects of Consecutive Wideband Tympanometry Trials on Energy Absorbance Measures of the Middle Ear

    ERIC Educational Resources Information Center

    Burdiek, Laina M.; Sun, Xiao-Ming

    2014-01-01

    Purpose: Wideband acoustic immittance (WAI) is a new technique for assessing middle ear transfer function. It includes energy absorbance (EA) measures and can be acquired with the ear canal pressure varied, known as "wideband tympanometry" (WBTymp). The authors of this study aimed to investigate effects of consecutive WBTymp testing on…

  19. Advances in Thermal Spray Coatings for Gas Turbines and Energy Generation: A Review

    NASA Astrophysics Data System (ADS)

    Hardwicke, Canan U.; Lau, Yuk-Chiu

    2013-06-01

    Functional coatings are widely used in energy generation equipment in industries such as renewables, oil and gas, propulsion engines, and gas turbines. Intelligent thermal spray processing is vital in many of these areas for efficient manufacturing. Advanced thermal spray coating applications include thermal management, wear, oxidation, corrosion resistance, sealing systems, vibration and sound absorbance, and component repair. This paper reviews the current status of materials, equipment, processing, and properties' aspects for key coatings in the energy industry, especially the developments in large-scale gas turbines. In addition to the most recent industrial advances in thermal spray technologies, future technical needs are also highlighted.

  20. Thermal Comfort and Strategies for Energy Conservation.

    ERIC Educational Resources Information Center

    Rohles, Frederick H., Jr.

    1981-01-01

    Discusses studies in thermal comfort which served as the basis for the comfort standard. Examines seven variables in the human response to the thermal environment in terms of the ways in which they can be modified to conserve energy. (Author/MK)

  1. Energy conservation, using remote thermal scanning

    NASA Technical Reports Server (NTRS)

    Bowman, R. L.; Jack, J. R.

    1978-01-01

    Airborne thermal infrared scans and thermal maps utilized in NASA's energy conservation program have proven to be efficient cost-effective method for identifying heat losses from building roofs and heating system distribution lines. Method employs commercially available equipment in highly developed way.

  2. TES (Thermal Energy Storage) Video News Release

    NASA Technical Reports Server (NTRS)

    1994-01-01

    TES is an in-space technology experiment that flew on STS-62. Its intent is to investigate the behavior of two different thermal energy storage materials as they undergo repeated melting and freezing in the microgravity environment.

  3. Modeling Laser-Tissue Interactions: Implementing the Heat Diffusion Equation and Wave Equation to Simulate Thermal Interactions of Absorber Distributions in Biological Tissues

    NASA Astrophysics Data System (ADS)

    Barrera, Frederick; Ahmed, Elharith; Nash, Patrick; Sardar, Dhiraj

    2011-03-01

    The tracking of photons through turbid media (e.g. tissues) has been studied extensively from an experimental vantage point. These turbid media are difficult to characterize- since their components are exceedingly variegated- and thus present many challenges to clinicians who require models which precisely predict the location and time evolution of energy deposition. Furthermore, the interaction of the turbid media sample with the source of radiation typically involves many dynamic mechanisms (e.g. photothermal etc.) Using diffuse light transport, and an electromagnetic wave approach (e.g. Maxwell's equations), an analysis of thermal energy distribution in tissues is performed. Assuming a highly absorbing chromophore model of melanocytes in tissues, a comparison of the variation of thermal energy is determined for different collections of melanocyte spatial distributions. This work was funded by NIH/NIGMS MBRS-RISE GM60655.

  4. Efficient hybrid electric and thermal energy generation

    NASA Astrophysics Data System (ADS)

    Xia, X. Winston; Parfenov, Alexander V.; Aye, Tin M.; Shih, Min-Yi

    2011-10-01

    We demonstrate a novel hybrid solar photovoltaic electrical and thermal energy cogeneration system with high efficiency, at potentially reduced overall weight and size compared with current solar energy systems. The new system is based on highly efficient photovoltaic solar cells and tubular water thermal receivers, incorporating holographic spectral beam light guide concentrators resulting in a more cost-effective solution. Details of fabrication and preliminary experimental testing results are presented.

  5. Ocean Thermal Energy Conversion: An overview

    SciTech Connect

    Not Available

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the US Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential -- either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. This publication provides an overview of the OTEC technology. 47 refs., 25 figs.

  6. Ocean thermal energy conversion: An overview

    NASA Astrophysics Data System (ADS)

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the U.S. Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential; either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. An overview of the OTEC technology is provided.

  7. Impact Testing and Simulation of a Sinusoid Foam Sandwich Energy Absorber

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L; Littell, Justin D.

    2015-01-01

    A sinusoidal-shaped foam sandwich energy absorber was developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research project. The energy absorber, designated the "sinusoid," consisted of hybrid carbon- Kevlar® plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical or crush direction, and a closed-cell ELFOAM(TradeMark) P200 polyisocyanurate (2.0-lb/ft3) foam core. The design goal for the energy absorber was to achieve an average floor-level acceleration of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in the design were assessed through quasi-static and dynamic crush testing of component specimens. Once the design was finalized, a 5-ft-long subfloor beam was fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorber prior to retrofit into TRACT 2. Finite element models were developed of all test articles and simulations were performed using LSDYNA ®, a commercial nonlinear explicit transient dynamic finite element code. Test analysis results are presented for the sinusoid foam sandwich energy absorber as comparisons of load-displacement and acceleration-time-history responses, as well as predicted and experimental structural deformations and progressive damage for each evaluation level (component testing through barrel section drop testing).

  8. Partitioning of absorbed light energy differed between the sun-exposed side and the shaded side of apple fruits under high light conditions.

    PubMed

    Chen, Changsheng; Zhang, Di; Li, Pengmin; Ma, Fengwang

    2012-11-01

    Fractions of absorbed light energy consumed via photochemistry and different thermal dissipation processes was quantified and compared between the sun-exposed peel and the shaded peel of apple fruits at different developmental stages. During fruit development, the fraction of absorbed light consumed via photochemistry was no more than 7% in the sun-exposed peel and no more than 5% in the shaded peel under high light conditions. Under high light, the fraction of absorbed light energy consumed via light dependent thermal dissipation was higher whereas that via constitutive thermal dissipation was lower in the sun-exposed peel. The light dependent thermal dissipation in the sun-exposed peel mainly depended on the xanthophyll cycle, and the xanthophyll cycle pool size was significantly larger in the sun-exposed peel than in the shaded peel. The light dependent thermal dissipation in the shaded peel was dependent on both the xanthophyll cycle and the presence of inactivated reaction centers. Under high light conditions, the densities of both Q(A)-reducing reaction centers and Q(B)-reducing reaction centers decreased faster in the shaded peel than in the sun-exposed peel. The thermal dissipation related to photoinhibition increased and then kept unchanged in the sun-exposed peel but decreased in the shaded peel during fruit development. We conclude that under high light intensities, fruit peel looses the excess energy in order of predominance: first by the xanthophyll cycle, then the thermal dissipation related to photoinhibition, next through inactivated reaction centers, and finally by constitutive thermal dissipation.

  9. Cyanine dyes with high-absorbance cross section as donor chromophores in energy transfer labels

    DOEpatents

    Glazer, A.N.; Mathies, R.A.; Hung, S.C.; Ju, J.

    1998-12-29

    Cyanine dyes are used as the donor fluorophore in energy transfer labels in which light energy is absorbed by a donor fluorophore and transferred to an acceptor fluorophore which responds to the transfer by emitting fluorescent light for detection. The cyanine dyes impart an unusually high sensitivity to the labels thereby improving their usefulness in a wide variety of biochemical procedures, particularly nucleic acid sequencing, nucleic acid fragment sizing, and related procedures. 22 figs.

  10. Cyanine dyes with high-absorbance cross section as donor chromophores in energy transfer labels

    DOEpatents

    Glazer, Alexander N.; Mathies, Richard A.; Hung, Su-Chun; Ju, Jingyue

    1998-01-01

    Cyanine dyes are used as the donor fluorophore in energy transfer labels in which light energy is absorbed by a donor fluorophore and transferred to an acceptor fluorophore which responds to the transfer by emitting fluorescent light for detection. The cyanine dyes impart an unusually high sensitivity to the labels thereby improving their usefulness in a wide variety of biochemical procedures, particularly nucleic acid sequencing, nucleic acid fragment sizing, and related procedures.

  11. Performance evaluation and parameter sensitivity of energy-harvesting shock absorbers on different vehicles

    NASA Astrophysics Data System (ADS)

    Guo, Sijing; Liu, Yilun; Xu, Lin; Guo, Xuexun; Zuo, Lei

    2016-07-01

    Traditional shock absorbers provide favourable ride comfort and road handling by dissipating the suspension vibration energy into heat waste. In order to harvest this dissipated energy and improve the vehicle fuel efficiency, many energy-harvesting shock absorbers (EHSAs) have been proposed in recent years. Among them, two types of EHSAs have attracted much attention. One is a traditional EHSA which converts the oscillatory vibration into bidirectional rotation using rack-pinion, ball-screw or other mechanisms. The other EHSA is equipped with a mechanical motion rectifier (MMR) that transforms the bidirectional vibration into unidirectional rotation. Hereinafter, they are referred to as NonMMR-EHSA and MMR-EHSA, respectively. This paper compares their performances with the corresponding traditional shock absorber by using closed-form analysis and numerical simulations on various types of vehicles, including passenger cars, buses and trucks. Results suggest that MMR-EHSA provides better ride performances than NonMMR-EHSA, and that MMR-EHSA is able to improve both the ride comfort and road handling simultaneously over the traditional shock absorber when installed on light-damped, heavy-duty vehicles. Additionally, the optimal parameters of MMR-EHSA are obtained for ride comfort. The optimal solutions ('Pareto-optimal solutions') are also obtained by considering the trade-off between ride comfort and road handling.

  12. Technical use of solar energy: Conversion from solar to thermal energy, solar cooling and thermal energy storage

    NASA Astrophysics Data System (ADS)

    Arafa, A.; Fisch, N.; Hahne, E.; Kraus, K.; Seemann, D.; Seifert, B.; Sohns, J.; Schetter, G.; Schweigerer, W.

    1983-12-01

    Experimental and theoretical studies in the field of solar energy utilization are reviewed. Specific topics considered are: flat plate water collectors, solar absorbers, air collectors, solar absorption cooling, solar simulators, aquifiers, latent heat stores, and space heating systems.

  13. Design, Fabrication and Testing of a Crushable Energy Absorber for a Passive Earth Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Corliss, James M. (Technical Monitor)

    2002-01-01

    A conceptual study was performed to investigate the impact response of a crushable energy absorber for a passive Earth entry vehicle. The spherical energy-absorbing concept consisted of a foam-filled composite cellular structure capable of omni-directional impact-load attenuation as well as penetration resistance. Five composite cellular samples of hemispherical geometry were fabricated and tested dynamically with impact speeds varying from 30 to 42 meters per second. Theoretical crush load predictions were obtained with the aid of a generalized theory which accounts for the energy dissipated during the folding deformation of the cell-walls. Excellent correlation was obtained between theoretical predictions and experimental tests on characteristic cell-web intersections. Good correlation of theory with experiment was also found to exist for the more complex spherical cellular structures. All preliminary design requirements were met by the cellular structure concept, which exhibited a near-ideal sustained crush-load and approximately 90% crush stroke.

  14. Thermal Energy Storage Flight Experiment in Microgravity

    NASA Technical Reports Server (NTRS)

    Namkoong, David

    1992-01-01

    The Thermal Energy Storage Flight Experiment was designed to characterize void shape and location in LiF-based phase change materials in different energy storage configurations representative of advanced solar dynamic systems. Experiment goals and payload design are described in outline and graphic form.

  15. Incorporating piezoelectric energy harvester in tunable vibration absorber for application in multi-modal vibration reduction of a platform structure

    NASA Astrophysics Data System (ADS)

    Lee, Chun-Ying; Lin, Jia-Hong

    2017-02-01

    Tunable vibration absorber is an effective device to reduce the vibration of structure subjected to harmonic excitation. The vibration energy is transferred mostly to the absorber when the natural frequency of the absorber is tuned to the excitation frequency. In this study, a piezoelectric (PZT) transducer was incorporated into the absorber in order to harvest the vibration energy and still alleviate the vibration of a platform structure. The tuning in dynamic characteristics of the absorber was facilitated by controlling its tip mass. The design formulation of the absorber was presented with a single degree-of-freedom (SDOF) model having the equivalent parameters. In the meantime, an optimal electric load resistor was determined to maximize the power output from the PZT transducer. The experimental measurement validated the SDOF model with good accuracy both in the vibration response and the output electric voltage. Finally, the absorber was installed on a platform structure to investigate its vibration reduction and energy harvesting capability for the external disturbance frequency covering certain frequency span. With three resonance modes of the platform studied, the absorber was able to reduce more than 80% of its original vibration and harvest several folds of electric power comparing with the untuned absorber. Although the performance in vibration reduction was slightly influenced (<6%), the great increase in the electric energy harvested revealed the absorber design a good potential toward self-powered sensor or actuator applications.

  16. The use of lipids as phase change materials for thermal energy storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phase change materials (PCMs) are substances capable of absorbing and releasing large 2 amounts of thermal energy (heat or cold) as latent heat over constant temperature as they 3 undergo a change in state of matter (phase transition), commonly, between solid and 4 liquid phases. Since the late 194...

  17. Nonimaging concentrators for solar thermal energy. Final report

    SciTech Connect

    Winston, R.

    1980-03-21

    A small experimental solar collector test facility has been established on the campus of the University of Chicago. This capability has been used to explore applications of nonimaging optics for solar thermal concentration in three substantially different configurations: (1) a single stage system with moderate concentration on an evacuated absorber (a 5.25X evacuated tube Compound Parabolic Concentrator or CPC), (2) a two stage system with high concentration and a non-evacuated absorber (a 16X Fresnel lens/CPC type mirror) and (3) moderate concentration single stage systems with non-evacuated absorbers for lower temperature (a 3X and a 6.5X CPC). Prototypes of each of these systems have been designed, built and tested. The performance characteristics are presented. In addition a 73 m/sup 2/ experimental array of 3X non-evacuated CPC's has been installed in a school heating system on the Navajo Indian Reservation in New Mexico. The full array has a peak noon time efficiency of approx. 50% at ..delta..T = 50/sup 0/C above ambient and has supplied about half the school's heat load for the past two heating seasons. Several theoretical features of nonimaging concentration have been investigated including their long term energy collecting behavior. The measured performance of the different systems shows clearly that non-tracking concentrators can provide solar thermal energy from moderately high low temperature regimes (> 50/sup 0/C above ambient) up into the mid-temperature region (well above 200/sup 0/C above ambient). The measured efficiency at 220/sup 0/C for the 5.25X CPC was as high or higher than that for any of the commercial tracking systems tested.

  18. The role of thermal energy storage in industrial energy conservation

    NASA Technical Reports Server (NTRS)

    Duscha, R. A.; Masica, W. J.

    1979-01-01

    Thermal Energy Storage for Industrial Applications is a major thrust of the Department of Energy's Thermal Energy Storage Program. Utilizing Thermal Energy Storage (TES) with process or reject heat recovery systems is shown to be extremely beneficial for several applications. Recent system studies resulting from contracts awarded by the Department of Energy (DOE) identified four especially significant industries where TES appears attractive - food processing, paper and pulp, iron and steel, and cement. Potential annual fuel savings with large scale implementation of near term TES systems for these industries is over 9,000,000 bbl of oil. This savings is due to recuperation and storage in the food processing industry, direct fuel substitution in the paper and pulp industry and reduction in electric utility peak fuel use through inplant production of electricity from utilization of reject heat in the steel and cement industries.

  19. Evaluation of New Thermally Conductive Geopolymer in Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    Černý, Matěj; Uhlík, Jan; Nosek, Jaroslav; Lachman, Vladimír; Hladký, Radim; Franěk, Jan; Brož, Milan

    This paper describes an evaluation of a newly developed thermally conductive geopolymer (TCG), consisting of a mixture of sodium silicate and carbon micro-particles. The TCG is intended to be used as a component of high temperature energy storage (HTTES) to improve its thermal diffusivity. Energy storage is crucial for both ecological and economical sustainability. HTTES plays a vital role in solar energy technologies and in waste heat recovery. The most advanced HTTES technologies are based on phase change materials or molten salts, but suffer with economic and technological limitations. Rock or concrete HTTES are cheaper, but they have low thermal conductivity without incorporation of TCG. It was observed that TCG is stable up to 400 °C. The thermal conductivity was measured in range of 20-23 W m-1 K-1. The effect of TCG was tested by heating a granite block with an artificial fissure. One half of the fissure was filled with TCG and the other with ballotini. 28 thermometers, 5 dilatometers and strain sensors were installed on the block. The heat transport experiment was evaluated with COMSOL Multiphysics software.

  20. Estimation of RF energy absorbed in the brain from mobile phones in the Interphone Study

    PubMed Central

    Varsier, N; Bowman, J D; Deltour, I; Figuerola, J; Mann, S; Moissonnier, M; Taki, M; Vecchia, P; Villegas, R; Vrijheid, M; Wake, K; Wiart, J

    2011-01-01

    Objectives The objective of this study was to develop an estimate of a radio frequency (RF) dose as the amount of mobile phone RF energy absorbed at the location of a brain tumour, for use in the Interphone Epidemiological Study. Methods We systematically evaluated and quantified all the main parameters thought to influence the amount of specific RF energy absorbed in the brain from mobile telephone use. For this, we identified the likely important determinants of RF specific energy absorption rate during protocol and questionnaire design, we collected information from study subjects, network operators and laboratories involved in specific energy absorption rate measurements and we studied potential modifiers of phone output through the use of software-modified phones. Data collected were analysed to assess the relative importance of the different factors, leading to the development of an algorithm to evaluate the total cumulative specific RF energy (in joules per kilogram), or dose, absorbed at a particular location in the brain. This algorithm was applied to Interphone Study subjects in five countries. Results The main determinants of total cumulative specific RF energy from mobile phones were communication system and frequency band, location in the brain and amount and duration of mobile phone use. Though there was substantial agreement between categorisation of subjects by cumulative specific RF energy and cumulative call time, misclassification was non-negligible, particularly at higher frequency bands. Factors such as adaptive power control (except in Code Division Multiple Access networks), discontinuous transmission and conditions of phone use were found to have a relatively minor influence on total cumulative specific RF energy. Conclusions While amount and duration of use are important determinants of RF dose in the brain, their impact can be substantially modified by communication system, frequency band and location in the brain. It is important to take

  1. Molten Salt Thermal Energy Storage Systems

    NASA Technical Reports Server (NTRS)

    Maru, H. C.; Dullea, J. F.; Kardas, A.; Paul, L.; Marianowski, L. G.; Ong, E.; Sampath, V.; Huang, V. M.; Wolak, J. C.

    1978-01-01

    The feasibility of storing thermal energy at temperatures of 450 C to 535 C in the form of latent heat of fusion was examined for over 30 inorganic salts and salt mixtures. Alkali carbonate mixtures were chosen as phase-change storage materials in this temperature range because of their relatively high storage capacity and thermal conductivity, moderate cost, low volumetric expansion upon melting, low corrosivity, and good chemical stability. Means of improving heat conduction through the solid salt were explored.

  2. Finite Element Analysis of an Energy Absorbing Sub-floor Structure

    NASA Technical Reports Server (NTRS)

    Moore, Scott C.

    1995-01-01

    As part of the Advanced General Aviation Transportation Experiments program, the National Aeronautics and Space Administration's Langley Research Center is conducting tests to design energy absorbing structures to improve occupant survivability in aircraft crashes. An effort is currently underway to design an Energy Absorbing (EA) sub-floor structure which will reduce occupant loads in an aircraft crash. However, a recent drop test of a fuselage specimen with a proposed EA sub-floor structure demonstrated that the effects of sectioning the fuselage on both the fuselage section's stiffness and the performance of the EA structure were not fully understood. Therefore, attempts are underway to model the proposed sub-floor structure on computers using the DYCAST finite element code to provide a better understanding of the structure's behavior in testing, and in an actual crash.

  3. Development of an energy-absorbing passenger seat for a transport aircraft

    NASA Technical Reports Server (NTRS)

    Eichelberger, C. P.; Alfaro-Bou, E.; Fasanella, E. L.

    1985-01-01

    Commercial air transport passenger safety and survivability, in the event of an impact-survivable crash, are subjects receiving increased technical focus/study by the aviation community. A B-720 aircraft, highly instrumented, and remotely controlled from the ground by a pilot in a simulated cockpit, was crashed on a specially prepared gravel covered impact site. The aircraft was impacted under controlled conditions in an air-to-ground gear-up mode, at a nominal speed of 150 knots and 4-1/2 deg glide slope. Data from a number of on board, crash worthiness experiments provided valuable information related to structural loads/failure modes, antimisting kerosene fuel, passenger and attendant restraint systems and energy absorbing seats. The development of an energy absorbing (EA) seat accomplished through innovative modification of a typical modern standard commercial aviation transport, three passenger seat is described.

  4. Calculation of fluence and absorbed dose in head tissues due to different photon energies.

    PubMed

    Azorín, C; Vega-Carrillo, H R; Rivera, T; Azorín, J

    2014-01-01

    Calculations of fluence and absorbed dose in head tissues due to different photon energies were carried out using the MCNPX code, to simulate two models of a patient's head: one spherical and another more realistic ellipsoidal. Both head models had concentric shells to describe the scalp skin, the cranium and the brain. The tumor was located at the center of the head and it was a 1 cm-radius sphere. The MCNPX code was run for different energies. Results showed that the fluence decreases as the photons pass through the different head tissues. It can be observed that, although the fluence into the tumor is different for both head models, absorbed dose is the same.

  5. Thermal energy in Robertson-Walker universes

    NASA Astrophysics Data System (ADS)

    Ruiz, Fernando Ruiz

    1989-03-01

    The covariant functional Schrödinger formalism is used to study thermal equilibrium for a scalar field in Robertson-Walker spacetimes. It is found that thermal equilibrium can be maintained for field masses, coupling constants and geometries satisfying a given differential equation, of which the massless conformally coupled case is a solution, but not the only one. The thermal energy is computed; it contains a term which for particular geometries, such as de Sitter spacetime, grows in time. On leave of absence from Departamento de Física Teórica, Universidad Complutense, 28040 Madrid 3, Spain.

  6. Numerical simulation of energy-absorbing capacity of metal sheet under penetration

    NASA Astrophysics Data System (ADS)

    Kaminishi, K.

    1997-07-01

    A finite element program employing a new explicit and consistent scheme for dynamic plasticity problems has been developed and deformation analysis of metal sheet under penetration has been carried out by this program. On the basis of this simulation, formulae for estimating the energy-absorbing capacity of thin metal sheet are proposed and the validity of this formulae has been shown numerically and experimentally.

  7. Methacrylic resin having a high solar radiant energy absorbing property and process for producing the same

    SciTech Connect

    Abe, K.; Kamada, K.; Nakai, Y.

    1981-10-20

    A methacrylic resin having a high solar radiant energy absorbing property wherein an organic compound (A) containing cupric ion and a compound (B) having at least one p-o-h bond in a molecule are contained into the methacrylic resin selected from poly(Methyl methacrylate) or methacrylic polymers containing at least 50% by weight of a methyl methacrylate unit. A process for producing said methacrylic resin is also disclosed.

  8. Thermal energy harvesting plasmonic based chemical sensors.

    PubMed

    Karker, Nicholas; Dharmalingam, Gnanaprakash; Carpenter, Michael A

    2014-10-28

    Detection of gases such as H2, CO, and NO2 at 500 °C or greater requires materials with thermal stability and reliability. One of the major barriers toward integration of plasmonic-based chemical sensors is the requirement of multiple components such as light sources and spectrometers. In this work, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis offers a novel path toward simplification and integration of plasmonic-based sensing methods.

  9. Spatial distribution of thermal energy in equilibrium.

    PubMed

    Bar-Sinai, Yohai; Bouchbinder, Eran

    2015-06-01

    The equipartition theorem states that in equilibrium, thermal energy is equally distributed among uncoupled degrees of freedom that appear quadratically in the system's Hamiltonian. However, for spatially coupled degrees of freedom, such as interacting particles, one may speculate that the spatial distribution of thermal energy may differ from the value predicted by equipartition, possibly quite substantially in strongly inhomogeneous or disordered systems. Here we show that for systems undergoing simple Gaussian fluctuations around an equilibrium state, the spatial distribution is universally bounded from above by 1/2k(B)T. We further show that in one-dimensional systems with short-range interactions, the thermal energy is equally partitioned even for coupled degrees of freedom in the thermodynamic limit and that in higher dimensions nontrivial spatial distributions emerge. Some implications are discussed.

  10. Spatial and spectral distributions of thermal radiation emitted by a semi-infinite body and absorbed by a flat film

    SciTech Connect

    Blandre, Etienne Chapuis, Pierre-Olivier; Vaillon, Rodolphe; Francoeur, Mathieu

    2015-05-15

    We analyze the radiative power emitted by a semi-infinite medium and absorbed by a flat film located in its vicinity. In the near-field regime, if the film is thin enough, the surface waves at the rear interface of the film can contribute to the heat transfer. As a result, the absorbed power can be enhanced farther from the front surface. In the near-to-far field transition regime, temporal coherence of thermal radiation and the associated interferences can be used to shape the spectrum of the transferred radiative heat flux by selecting approriate geometrical parameters. These results highlight possibilities to control both the location where the radiative power is absorbed in the film and the spectral distribution, which are of paramount importance for applications such as near-field thermophotovoltaics.

  11. Cost-Effective Solar Thermal Energy Storage: Thermal Energy Storage With Supercritical Fluids

    SciTech Connect

    2011-02-01

    Broad Funding Opportunity Announcement Project: UCLA and JPL are creating cost-effective storage systems for solar thermal energy using new materials and designs. A major drawback to the widespread use of solar thermal energy is its inability to cost-effectively supply electric power at night. State-of-the-art energy storage for solar thermal power plants uses molten salt to help store thermal energy. Molten salt systems can be expensive and complex, which is not attractive from a long-term investment standpoint. UCLA and JPL are developing a supercritical fluid-based thermal energy storage system, which would be much less expensive than molten-salt-based systems. The team’s design also uses a smaller, modular, single-tank design that is more reliable and scalable for large-scale storage applications.

  12. Design, Fabrication, and Testing of Composite Energy-Absorbing Keel Beams for General Aviation Type Aircraft

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Knight, Norman F., Jr.

    2002-01-01

    A lightweight energy-absorbing keel-beam concept was developed and retrofitted in a general aviation type aircraft to improve crashworthiness performance. The energy-absorbing beam consisted of a foam-filled cellular structure with glass fiber and hybrid glass/kevlar cell walls. Design, analysis, fabrication and testing of the keel beams prior to installation and subsequent full-scale crash testing of the aircraft are described. Factors such as material and fabrication constraints, damage tolerance, crush stress/strain response, seat-rail loading, and post crush integrity, which influenced the course of the design process are also presented. A theory similar to the one often used for ductile metal box structures was employed with appropriate modifications to estimate the sustained crush loads for the beams. This, analytical tool, coupled with dynamic finite element simulation using MSC.Dytran were the prime design and analysis tools. The validity of the theory as a reliable design tool was examined against test data from static crush tests of beam sections while the overall performance of the energy-absorbing subfloor was assessed through dynamic testing of 24 in long subfloor assemblies.

  13. Aquifer thermal energy (heat and chill) storage

    SciTech Connect

    Jenne, E.A.

    1992-11-01

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  14. Spacecraft thermal energy accommodation from atomic recombination

    NASA Technical Reports Server (NTRS)

    Carleton, Karen L.; Marinelli, William J.

    1991-01-01

    Measurements of atomic recombination probabilities important in determining energy release to reusable spacecraft thermal protection surfaces during reentry are presented. An experimental apparatus constructed to examine recombination of atomic oxygen from thermal protection and reference materials at reentry temperatures is described. The materials are examined under ultrahigh vacuum conditions to develop and maintain well characterized surface conditions that are free of contamination. When compared with stagnation point heat transfer measurements performed in arc jet facilities, these measurements indicate that a significant fraction of the excess energy available from atom recombination is removed from the surface as metastable O2.

  15. LiH thermal energy storage device

    DOEpatents

    Olszewski, M.; Morris, D.G.

    1994-06-28

    A thermal energy storage device for use in a pulsed power supply to store waste heat produced in a high-power burst operation utilizes lithium hydride as the phase change thermal energy storage material. The device includes an outer container encapsulating the lithium hydride and an inner container supporting a hydrogen sorbing sponge material such as activated carbon. The inner container is in communication with the interior of the outer container to receive hydrogen dissociated from the lithium hydride at elevated temperatures. 5 figures.

  16. Thermal energy recycling fuel cell arrangement

    DOEpatents

    Hanrahan, Paul R.

    2017-04-11

    An example fuel cell arrangement includes a fuel cell stack configured to receive a supply fluid and to provide an exhaust fluid that has more thermal energy than the supply fluid. The arrangement also includes an ejector and a heat exchanger. The ejector is configured to direct at least some of the exhaust fluid into the supply fluid. The heat exchanger is configured to increase thermal energy in the supply fluid using at least some of the exhaust fluid that was not directed into the supply fluid.

  17. Aquifer thermal energy storage. International symposium: Proceedings

    SciTech Connect

    1995-05-01

    Aquifers have been used to store large quantities of thermal energy to supply process cooling, space cooling, space heating, and ventilation air preheating, and can be used with or without heat pumps. Aquifers are used as energy sinks and sources when supply and demand for energy do not coincide. Aquifer thermal energy storage may be used on a short-term or long-term basis; as the sole source of energy or as a partial storage; at a temperature useful for direct application or needing upgrade. The sources of energy used for aquifer storage are ambient air, usually cold winter air; waste or by-product energy; and renewable energy such as solar. The present technical, financial and environmental status of ATES is promising. Numerous projects are operating and under development in several countries. These projects are listed and results from Canada and elsewhere are used to illustrate the present status of ATES. Technical obstacles have been addressed and have largely been overcome. Cold storage in aquifers can be seen as a standard design option in the near future as it presently is in some countries. The cost-effectiveness of aquifer thermal energy storage is based on the capital cost avoidance of conventional chilling equipment and energy savings. ATES is one of many developments in energy efficient building technology and its success depends on relating it to important building market and environmental trends. This paper attempts to provide guidance for the future implementation of ATES. Individual projects have been processed separately for entry onto the Department of Energy databases.

  18. Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

    NASA Astrophysics Data System (ADS)

    Gao, Xiang-Hu; Wang, Cheng-Bing; Guo, Zhi-Ming; Geng, Qing-Fen; Theiss, Wolfgang; Liu, Gang

    2016-08-01

    Traditional metal-dielectric composite coating has found important application in spectrally selective solar absorbers. However, fine metal particles can easily diffuse, congregate, or be oxidized at high temperature, which causes deterioration in the optical properties. In this work, we report a new spectrally selective solar absorber coating, composed of low Al2O3 ceramic volume fraction (Al2O3(L)-WC) layer, high Al2O3 ceramic volume fraction (Al2O3(H)-WC layer) and Al2O3 antireflection layer. The features of our work are: 1) compared with the metal-dielectric composites concept, Al2O3-WC nanocomposite ceramic successfully achieves the all-ceramic concept, which exhibits a high solar absorptance of 0.94 and a low thermal emittance of 0.08, 2) Al2O3 and WC act as filler material and host material, respectively, which are different from traditional concept, 3) Al2O3-WC nanocomposite ceramic solar absorber coating exhibits good thermal stability at 600 °C. In addition, the solar absorber coating is successfully modelled by a commercial optical simulation programme, the result of which agrees with the experimental results.

  19. Applications and challenges for thermal energy storage

    NASA Astrophysics Data System (ADS)

    Kannberg, L. D.; Tomlinson, J. T.

    1991-04-01

    New thermal energy storage (TES) technologies are being developed and applied as society strives to relieve increasing energy and environmental stresses. Applications for these new technologies range from residential and district heating and cooling using waste and solar energy, to high-temperature energy storage for power production and industrial processes. In the last two decades there has been great interest and development of heat storage systems, primarily for residential and commercial buildings. While development has continued, the rate of advancement has slowed with current technology considered adequate for electrically charged heat storage furnaces. Use of chill storage for building diurnal cooling has received substantial development.

  20. Thermal Insulation Strips Conserve Energy

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Launching the space shuttle involves an interesting paradox: While the temperatures inside the shuttle s main engines climb higher than 6,000 F hot enough to boil iron for fuel, the engines use liquid hydrogen, the second coldest liquid on Earth after liquid helium. Maintained below 20 K (-423 F), the liquid hydrogen is contained in the shuttle s rust-colored external tank. The external tank also contains liquid oxygen (kept below a somewhat less chilly 90 K or -297 F) that combines with the hydrogen to create an explosive mixture that along with the shuttle s two, powdered aluminum-fueled solid rocket boosters allows the shuttle to escape Earth s gravity. The cryogenic temperatures of the main engines liquid fuel can cause ice, frost, or liquefied air to build up on the external tank and other parts of the numerous launch fueling systems, posing a possible debris risk when the ice breaks off during launch and causing difficulties in the transfer and control of these cryogenic liquid propellants. Keeping the fuel at the necessary ultra-cold temperatures while minimizing ice buildup and other safety hazards, as well as reducing the operational maintenance costs, has required NASA to explore innovative ways for providing superior thermal insulation systems. To address the challenge, the Agency turned to an insulating technology so effective that, even though it is mostly air, a thin sheet can prevent a blowtorch from igniting a match. Aerogels were invented in 1931 and demonstrate properties that make them the most extraordinary insulating materials known; a 1-inch-thick piece of aerogel provides the same insulation as layering 15 panes of glass with air pockets in between. Derived from silica, aluminum oxide, or carbon gels using a supercritical drying process - resulting in a composition of almost 99-percent air - aerogels are the world s lightest solid (among 15 other titles they hold in the Guinness World Records), can float indefinitely on water if treated to be

  1. Ocean thermal energy conversion: Materials issues

    NASA Astrophysics Data System (ADS)

    Darby, J. B., Jr.

    The Ocean thermal Energy Conversion (OTEC) Program, in the Ocean Energy Technology Division of the U.S. Department of Energy, is concerned with the development of options that can be utilized to extract and distribute significant amounts of energy from the ocean. The biofouling control and materials portion of the program is concerned with the development of effective and environmentally acceptable methods to minimize biofouling and corrosion in high thermal conductivity materials suitable for use in heat exchangers and condensers. The mechanical and chemical techniques employed for biofouling control are reviewed and the recent success with chlorination is presented. The corrosion of aluminum alloys, copper alloys, stainless steel, stainless alloys, and titanium in near-surface warm and deep cold water is reviewed with emphasis on aluminum alloys. The major materials issues are reviewed with emphasis on lifetime and cost.

  2. Making `Internal Thermal Energy' Visible

    NASA Astrophysics Data System (ADS)

    Zou, Xueli

    2004-09-01

    In a 1992 paper published in this journal, Uri Ganiel described a pair of model carts used to demonstrate elastic and inelastic collisions. The wooden carts had low-friction wheels and a steel-strip bumper on one end. On one of the carts, a number of brass washers were rigidly mounted in vertical stacks to a wooden framework. The other cart was similar except that the washers were tied to rubber bands that were stretched horizontally and diagonally across the framework. When the first cart was rolled into a wall it bounced off with only a small reduction in speed ("elastic" collision). The second cart, on the other hand, was found to come nearly to a complete stop upon colliding with the wall ("inelastic" collision). Following the instructions given in Ganiel's paper, I built a pair of carts and demonstrated them to introductory-level physics students at a large public university. It was interesting to find that many students were distracted by the different-looking structures of the two model carts.2 They thought the different distributions of washers between the carts resulted in the rubber-band cart bouncing back a significantly shorter distance than the rigid-rod one after they both collided with a wall at the same initial speed. Apparently, the students had difficulties in understanding the collisions and used surface features to reason about them. To avoid this superficial distraction and to help students visualize easily "where the kinetic energy goes in an inelastic collision," I modified the rigid-rod cart to have washers fixed on hollow aluminum rods mounted at four different levels horizontally and diagonally (see Fig. 1). The new pair of the model carts look very similar to each other: They have the same bumpers, same wheels, same distributions of washers, and same masses.

  3. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting.

    PubMed

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-09-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed.

  4. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    PubMed Central

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-01-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed. PMID:27582317

  5. Point-by-point near-field optical energy deposition around plasmonic nanospheres in absorbing media.

    PubMed

    Harrison, R K; Ben-Yakar, Adela

    2015-08-01

    Here we investigate the effects of absorbing media on plasmon-enhanced near-field optical energy deposition. We find that increasing absorption by the medium results in increased particle scattering at the expense of particle absorption, and that much of this increased particle scattering is absorbed by the medium close to the particle surface. We present an analytical method for evaluating the spatial distribution of near-field enhanced absorption surrounding plasmonic metal nanospheres in absorbing media using a new point-by-point method. We propose criteria to define relevant near-field boundaries and calculate the properties of the local absorption enhancement, which redistributes absorption to the near-field and decays asymptotically as a function of the distance from the particle to background levels. Using this method, we performed a large-scale parametric study to understand the effect of particle size and wavelength on the near-field absorption for gold nanoparticles in aqueous media and silicon, and identified conditions that are relevant to enhanced local infrared absorption in silicon. The presented approach provides insight into the local energy transfer around plasmonic nanoparticles for predicting near-field effects for advanced concepts in optical sensing, thin-film solar cells, nonlinear imaging, and photochemical applications.

  6. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-09-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed.

  7. The series elastic shock absorber: tendon elasticity modulates energy dissipation by muscle during burst deceleration.

    PubMed

    Konow, Nicolai; Roberts, Thomas J

    2015-04-07

    During downhill running, manoeuvring, negotiation of obstacles and landings from a jump, mechanical energy is dissipated via active lengthening of limb muscles. Tendon compliance provides a 'shock-absorber' mechanism that rapidly absorbs mechanical energy and releases it more slowly as the recoil of the tendon does work to stretch muscle fascicles. By lowering the rate of muscular energy dissipation, tendon compliance likely reduces the risk of muscle injury that can result from rapid and forceful muscle lengthening. Here, we examine how muscle-tendon mechanics are modulated in response to changes in demand for energy dissipation. We measured lateral gastrocnemius (LG) muscle activity, force and fascicle length, as well as leg joint kinematics and ground-reaction force, as turkeys performed drop-landings from three heights (0.5-1.5 m centre-of-mass elevation). Negative work by the LG muscle-tendon unit during landing increased with drop height, mainly owing to greater muscle recruitment and force as drop height increased. Although muscle strain did not increase with landing height, ankle flexion increased owing to increased tendon strain at higher muscle forces. Measurements of the length-tension relationship of the muscle indicated that the muscle reached peak force at shorter and likely safer operating lengths as drop height increased. Our results indicate that tendon compliance is important to the modulation of energy dissipation by active muscle with changes in demand and may provide a mechanism for rapid adjustment of function during deceleration tasks of unpredictable intensity.

  8. Phase change thermal energy storage material

    DOEpatents

    Benson, David K.; Burrows, Richard W.

    1987-01-01

    A thermal energy storge composition is disclosed. The composition comprises a non-chloride hydrate having a phase change transition temperature in the range of 70.degree.-95.degree. F. and a latent heat of transformation of at least about 35 calories/gram.

  9. Concrete for Ocean Thermal Energy, Conversion Structures.

    DTIC Science & Technology

    1976-08-01

    construction of massive floating structures to house ocean thermal energy conversion ( OTEC ) systems. The relevant capabilities and limitations of available...which reasonable improvements can be made in the near term to provide greater assurances of long-term safe and reliable operation of the OTEC systems and to provide lower cost structures. (Author)

  10. Modelling a point absorbing wave energy converter by the equivalent electric circuit theory: A feasibility study

    NASA Astrophysics Data System (ADS)

    Hai, Ling; Svensson, Olle; Isberg, Jan; Leijon, Mats

    2015-04-01

    There is a need to have a reliable tool to quickly assess wave energy converters (WECs). This paper explores whether it is possible to apply the equivalent electric circuit theory as an evaluation tool for point absorbing WEC system modelling. The circuits were developed starting from the force analysis, in which the hydrodynamic, mechanical, and electrical parameters were expressed by electrical components. A methodology on how to determine the parameters for electrical components has been explained. It is found that by using a multimeter, forces in the connection line and the absorbed electric power can be simulated and read directly from the electric circuit model. Finally, the circuit model has been validated against the full scale offshore experiment. The results indicated that the captured power could be predicted rather accurately and the line force could be estimated accurately near the designed working condition of the WEC.

  11. An APL program for the distribution of energy deposition by charged particles passing through thin absorbers

    NASA Technical Reports Server (NTRS)

    Howell, L. W.

    1985-01-01

    An APL program which numerically evaluates the probability density function (PDF) for the energy deposited in a thin absorber by a charged particle is proposed, with application to the construction, pointing, and control of spacecraft. With this program, the PDF of the restricted energy loss distribution of Watts (1973) is derived, and Vavilov's (1957) distribution is obtained by proper parameter selection. The method is demonstrated with the example of the effect of charged particle induced radiation on the Hubble Space Telescope (HST) pointing accuracy. A Monte Carlo study simulates the photon noise caused by charged particles passing through the photomultiplier tube window, and the stochastic variation of energy loss is introduced into the simulation by generating random energy losses from a power law distribution. The program eliminates annoying loop procedures, and model parameter sensitivity can be studied using the graphical output.

  12. Environmental impacts of ocean thermal energy conversion

    SciTech Connect

    Not Available

    1986-04-01

    Ocean thermal energy conversion (OTEC) is a promising technology for production of energy and usable by-products from solar-generated temperature gradients in the world's oceans. Although considered benign compared to alternative forms of energy generation, deployment of OTEC plants will result in interactions with marine, terrestrial, and atmospheric environments and in socioeconomic interactions with surrounding areas. The Ocean Energy Technology Program of the Department of Energy has funded research to improve the understanding of these interactions. No insurmountable environmental obstacle to OTEC deployment has been uncovered. This document contains a summary of that research for entrepreneurs, utility engineers, and others interested in pursuing OTEC's potential. In addition, it provides a guide to permits, regulations, and licenses applicable to construction of an OTEC plant.

  13. Differential absorbed dose distributions in lineal energy for neutrons and gamma rays at the mono-energetic neutron calibration facility.

    PubMed

    Takada, M; Baba, M; Yamaguchi, H; Fujitaka, K

    2005-01-01

    Absorbed dose distributions in lineal energy for neutrons and gamma rays of mono-energetic neutron sources from 140 keV to 15 MeV were measured in the Fast Neutron Laboratory at Tohoku University. By using both a tissue-equivalent plastic walled counter and a graphite-walled low-pressure proportional counter, absorbed dose distributions in lineal energy for neutrons were obtained separately from those for gamma rays. This method needs no knowledge of energy spectra and dose distributions for gamma rays. The gamma-ray contribution in this neutron calibration field >1 MeV neutron was <3%, while for <550 keV it was >40%. The measured neutron absolute absorbed doses per unit neutron fluence agreed with the LA150 evaluated kerma factors. By using this method, absorbed dose distributions in lineal energy for neutrons and gamma rays in an unknown neutron field can be obtained separately.

  14. Design and testing of an energy-absorbing crewseat for the F/FB-111 aircraft, volume 1

    NASA Technical Reports Server (NTRS)

    Shane, S. J.

    1985-01-01

    A program to determine if the injury potential could be reduced by replacing the existing crewseats with energy absorbing crewseats is explored. An energy-absorbing test seat was designed using much of the existing seat hardware. An extensive dynamic seat test series, designed to duplicate various crew module ground impact conditions, was conducted at a sled test facility. Comparative tests with operational F-111 crewseats were also conducted. After successful dynamic testing of the seat, more testing was conducted with the seats mounted in an F-111 crew module. Both swing tests and vertical drop tests were conducted. The vertical drop tests were used to obtain comparative data between the energy-absorbing and operational seats. Volume 1 describes the energy absorbing test seat and testing conducted, and evaluates the data from both test series.

  15. Diamond detector in absorbed dose measurements in high-energy linear accelerator photon and electron beams.

    PubMed

    Ravichandran, Ramamoorthy; Binukumar, John Pichy; Al Amri, Iqbal; Davis, Cheriyathmanjiyil Antony

    2016-03-08

    Diamond detectors (DD) are preferred in small field dosimetry of radiation beams because of small dose profile penumbras, better spatial resolution, and tissue-equivalent properties. We investigated a commercially available 'microdiamond' detector in realizing absorbed dose from first principles. A microdiamond detector, type TM 60019 with tandem electrometer is used to measure absorbed doses in water, nylon, and PMMA phantoms. With sensitive volume 0.004 mm3, radius 1.1mm, thickness 1 x10(-3) mm, the nominal response is 1 nC/Gy. It is assumed that the diamond detector could collect total electric charge (nC) developed during irradiation at 0 V bias. We found that dose rate effect is less than 0.7% for changing dose rate by 500 MU/min. The reproducibility in obtaining readings with diamond detector is found to be ± 0.17% (1 SD) (n = 11). The measured absorbed doses for 6 MV and 15 MV photons arrived at using mass energy absorption coefficients and stop-ping power ratios compared well with Nd, water calibrated ion chamber measured absorbed doses within 3% in water, PMMA, and nylon media. The calibration factor obtained for diamond detector confirmed response variation is due to sensitivity due to difference in manufacturing process. For electron beams, we had to apply ratio of electron densities of water to carbon. Our results qualify diamond dosimeter as a transfer standard, based on long-term stability and reproducibility. Based on micro-dimensions, we recommend these detectors for pretreatment dose verifications in small field irradiations like stereotactic treatments with image guidance.

  16. Balancing the energy budget of short-period giant planets: evidence for reflective clouds and optical absorbers

    NASA Astrophysics Data System (ADS)

    Schwartz, J. C.; Cowan, N. B.

    2015-06-01

    We consider 50 transiting short-period giant planets for which eclipse depths have been measured at multiple infrared wavelengths. The aggregate dayside emission spectrum of these planets exhibits no molecular features, nor is brightness temperature greater in the near-infrared. We combine brightness temperatures at various infrared wavelengths to estimate the dayside effective temperature of each planet. We find that dayside temperatures are proportional to irradiation temperatures, indicating modest Bond albedo and no internal energy sources. We place joint constraints on Bond albedo, AB, and day-to-night heat transport efficiency, ε, for six planets by combining thermal eclipse and phase variation measurements (HD 149026b, HD 189733b, HD 209458b, WASP-12b, WASP-18b, and WASP-43b). We confirm that planets with high irradiation temperatures have low heat transport and that WASP-43b has inexplicably poor transport; these results are statistically significant even if the precision of single-eclipse measurements has been overstated by a factor of 3. Lastly, we attempt to break the AB-ε degeneracy for nine planets with both thermal and optical eclipse observations, but no thermal phase measurements. We find a systematic offset between Bond albedos inferred from thermal phase variations (AB ≈ 0.35) and geometric albedos extracted from visible light measurements (Ag ≈ 0.1). These observations can be reconciled if most hot Jupiters have clouds that reflect 30-50 per cent of incident near-infrared radiation, and optical absorbers in the cloud particles or above the cloud deck.

  17. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    SciTech Connect

    Rothe, R.E.

    1996-09-30

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution`s concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the `Poisoned Tube Tank` because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service.

  18. Thermal Profiling of Residential Energy Use

    SciTech Connect

    Albert, A; Rajagopal, R

    2015-03-01

    This work describes a methodology for informing targeted demand-response (DR) and marketing programs that focus on the temperature-sensitive part of residential electricity demand. Our methodology uses data that is becoming readily available at utility companies-hourly energy consumption readings collected from "smart" electricity meters, as well as hourly temperature readings. To decompose individual consumption into a thermal-sensitive part and a base load (non-thermally-sensitive), we propose a model of temperature response that is based on thermal regimes, i.e., unobserved decisions of consumers to use their heating or cooling appliances. We use this model to extract useful benchmarks that compose thermal profiles of individual users, i.e., terse characterizations of the statistics of these users' temperature-sensitive consumption. We present example profiles generated using our model on real consumers, and show its performance on a large sample of residential users. This knowledge may, in turn, inform the DR program by allowing scarce operational and marketing budgets to be spent on the right users-those whose influencing will yield highest energy reductions-at the right time. We show that such segmentation and targeting of users may offer savings exceeding 100% of a random strategy.

  19. Aquifer thermal energy storage: a survey

    SciTech Connect

    Tsang, C.F.; Hopkins, D.; Hellstroem, G.

    1980-01-01

    The disparity between energy production and demand in many power plants has led to increased research on the long-term, large-scale storage of thermal energy in aquifers. Field experiments have been conducted in Switzerland, France, the United States, Japan, and the People's Republic of China to study various technical aspects of aquifer storage of both hot and cold water. Furthermore, feasibility studies now in progress include technical, economic, and environmental analyses, regional exploration to locate favorable storage sites, and evaluation and design of pilot plants. Several theoretical and modeling studies are also under way. Among the topics being studied using numerical models are fluid and heat flow, dispersion, land subsidence or uplift, the efficiency of different injection/withdrawal schemes, buoyancy tilting, numerical dispersion, the use of compensation wells to counter regional flow, steam injection, and storage in narrow glacial deposits of high permeability. Experiments to date illustrate the need for further research and development to ensure successful implementation of an aquifer storage system. Some of the areas identified for further research include shape and location of the hydrodynamic and thermal fronts, choice of appropriate aquifers, thermal dispersion, possibility of land subsidence or uplift, thermal pollution, water chemistry, wellbore plugging and heat exchange efficiency, and control of corrosion.

  20. Operational Experience from Solar Thermal Energy Projects

    NASA Technical Reports Server (NTRS)

    Cameron, C. P.

    1984-01-01

    Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

  1. Operational experience from solar thermal energy projects

    NASA Astrophysics Data System (ADS)

    Cameron, C. P.

    1984-03-01

    Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

  2. Solar Thermal Energy Storage Device: Hybrid Nanostructures for High-Energy-Density Solar Thermal Fuels

    SciTech Connect

    2012-01-09

    HEATS Project: MIT is developing a thermal energy storage device that captures energy from the sun; this energy can be stored and released at a later time when it is needed most. Within the device, the absorption of sunlight causes the solar thermal fuel’s photoactive molecules to change shape, which allows energy to be stored within their chemical bonds. A trigger is applied to release the stored energy as heat, where it can be converted into electricity or used directly as heat. The molecules would then revert to their original shape, and can be recharged using sunlight to begin the process anew. MIT’s technology would be 100% renewable, rechargeable like a battery, and emissions-free. Devices using these solar thermal fuels—called Hybrisol—can also be used without a grid infrastructure for applications such as de-icing, heating, cooking, and water purification.

  3. Energy, Power and Thermal Research Overview

    DTIC Science & Technology

    2010-09-01

    Research Overview Rick Fingers, Ph.D. Chief Energy/Power/Thermal Division Propulsion Directorate Air Force Research ... Air Vehicles Sensors AFOSR 5 AFRL People & Facilities • 10 Major R&D Sites across US • 40 Sites World-Wide • $40B Real Property & Capital throughout... AFRL • 5,764 Government Employees – 4570 Air Force Civilian – 1194 Military • 3,844 Onsite Contractors 6 Propulsion Directorate’s Strategic

  4. Development of Equipment to Separate Nonthermal and Thermal Effects of Radio Frequency Energy on Microorganisms

    SciTech Connect

    D.J. Geveke; M. Kozempel; C. Brunkhorst

    1999-11-01

    A radio frequency (RF) dielectric heater has been developed for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The modified heater enables the simultaneous application of RF energy and removal of thermal energy from the liquids. A double-pipe heat exchanger is an integral part of the heater. The outer pipe is made of Teflon. The inner pipe is made of stainless steel that is grounded in the RF circuit. Liquid food flows through the annular region between the two concentric pipes. Cooling water flows through the stainless steel pipe. The food in the annular region absorbs the RF energy. Concurrently, the cooling water flowing in the inner pipe removes the thermal energy from the food, thus controlling the temperature.

  5. Specific absorbed fractions of energy from internal photon sources in brain tumor and cerebrospinal fluid

    SciTech Connect

    Evans, J.F. )); Stubbs, J.B. )

    1995-03-01

    Transferrin, radiolabeled with In-111, can be coinjected into glioblastoma multiforme lesions, and subsequent scintigraphic imaging can demonstrate the biokinetics of the cytotoxic transferrin. The administration of [sup 111]In transferrin into a brain tumor results in distribution of radioactivity in the brain, brain tumor, and the cerebrospinal fluid (CSF). Information about absorbed radiation doses to these regions, as well as other nearby tissues and organs, is important for evaluating radiation-related risks from this procedure. The radiation dose is usually estimated for a mathematical representation of the human body. We have included source/target regions for the eye, lens of the eye, spinal column, spinal CSF, cranial CSF, and a 100-g tumor within the brain of an adult male phantom developed by Cristy and Eckerman. The spinal column, spinal CSF, and the eyes have not been routinely included in photon transport simulations. Specific absorbed fractions (SAFs) as a function of photon energy were calculated using the ALGAMP computer code, which utilizes Monte Carlo techniques for simulating photon transport. The ALGAMP code was run three times, with the source activity distributed uniformly within the tumor, cranial CSF, and the spinal CSF volumes. These SAFs, which were generated for 12 discrete photon energies ranging from 0.01 to 4.0 MeV, were used with decay scheme data to calculate [ital S]-values needed for estimating absorbed doses. [ital S]-values for [sup 111]In are given for three source regions (brain tumor, cranial CSF, and spinal CSF) and all standard target regions/organs, the eye and lens, as well as to tissues within these source regions. [ital S]-values for the skeletal regions containing active marrow are estimated. These results are useful in evaluating the radiation doses from intracranial administration of [sup 111]In transferrin.

  6. Analysis of lunar regolith thermal energy storage

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    1991-01-01

    The concept of using lunar regolith as a thermal energy storage medium was evaluated. The concept was examined by mathematically modeling the absorption and transfer of heat by the lunar regolith. Regolith thermal and physical properties were established through various sources as functions of temperature. Two cases were considered: a semi-infinite, constant temperature, cylindrical heat source embedded in a continuum of lunar regolith and a spherically shaped molten zone of lunar regolith set with an initial temperature profile. The cylindrical analysis was performed in order to examine the amount of energy which can be stored in the regolith during the day. At night, the cylinder acted as a perfect insulator. This cycling was performed until a steady state situation was reached in the surrounding regolith. It was determined that a cycling steady state occurs after approximately 15 day/night cycles. Results were obtained for cylinders of various diameters. The spherical molten zone analysis was performed to establish the amount of thermal energy, within the regolith, necessary to maintain some molten material throughout a nighttime period. This surrounding temperature profile was modeled after the cycling steady state temperature profile established by the cylindrical analysis. It was determined that a molten sphere diameter of 4.76 m is needed to maintain a core temperature near the low end of the melting temperature range throughout one nighttime period.

  7. Analytical Simulations of Energy-Absorbing Impact Spheres for a Mars Sample Return Earth Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Billings, Marcus Dwight; Fasanella, Edwin L. (Technical Monitor)

    2002-01-01

    Nonlinear dynamic finite element simulations were performed to aid in the design of an energy-absorbing impact sphere for a passive Earth Entry Vehicle (EEV) that is a possible architecture for the Mars Sample Return (MSR) mission. The MSR EEV concept uses an entry capsule and energy-absorbing impact sphere designed to contain and limit the acceleration of collected samples during Earth impact without a parachute. The spherical shaped impact sphere is composed of solid hexagonal and pentagonal foam-filled cells with hybrid composite, graphite-epoxy/Kevlar cell walls. Collected Martian samples will fit inside a smaller spherical sample container at the center of the EEV's cellular structure. Comparisons were made of analytical results obtained using MSC.Dytran with test results obtained from impact tests performed at NASA Langley Research Center for impact velocities from 30 to 40 m/s. Acceleration, velocity, and deformation results compared well with the test results. The correlated finite element model was then used for simulations of various off-nominal impact scenarios. Off-nominal simulations at an impact velocity of 40 m/s included a rotated cellular structure impact onto a flat surface, a cellular structure impact onto an angled surface, and a cellular structure impact onto the corner of a step.

  8. Full-Scale Crash Test of a MD-500 Helicopter with Deployable Energy Absorbers

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Jackson, Karen E.; Littell, Justin D.

    2010-01-01

    A new externally deployable energy absorbing system was demonstrated during a full-scale crash test of an MD-500 helicopter. The deployable system is a honeycomb structure and utilizes composite materials in its construction. A set of two Deployable Energy Absorbers (DEAs) were fitted on the MD-500 helicopter for the full-scale crash demonstration. Four anthropomorphic dummy occupants were also used to assess human survivability. A demonstration test was performed at NASA Langley's Landing and Impact Research Facility (LandIR). The test involved impacting the helicopter on a concrete surface with combined forward and vertical velocity components of 40-ft/s and 26-ft/s, respectively. The objectives of the test were to evaluate the performance of the DEA concept under realistic crash conditions and to generate test data for validation of dynamic finite element simulations. Descriptions of this test as well as other component and full-scale tests leading to the helicopter test are discussed. Acceleration data from the anthropomorphic dummies showed that dynamic loads were successfully attenuated to within non-injurious levels. Moreover, the airframe itself survived the relatively severe impact and was retested to provide baseline data for comparison for cases with and without DEAs.

  9. Impact Test and Simulation of Energy Absorbing Concepts for Earth Entry Vehicles

    NASA Technical Reports Server (NTRS)

    Billings, Marcus D.; Fasanella, Edwin L.; Kellas, Sotiris

    2001-01-01

    Nonlinear dynamic finite element simulations have been performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite- epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the center of the EEV's cellular structure. Comparisons of analytical predictions using MSC,Dytran with test results obtained from impact tests performed at NASA Langley Research Center were made for three impact velocities ranging from 32 to 40 m/s. Acceleration and deformation results compared well with the test results. These finite element models will be useful for parametric studies of off-nominal impact conditions.

  10. Absorbable energy monitoring scheme: new design protocol to test vehicle structural crashworthiness.

    PubMed

    Ofochebe, Sunday M; Enibe, Samuel O; Ozoegwu, Chigbogu G

    2016-05-01

    In vehicle crashworthiness design optimization detailed system evaluation capable of producing reliable results are basically achieved through high-order numerical computational (HNC) models such as the dynamic finite element model, mesh-free model etc. However the application of these models especially during optimization studies is basically challenged by their inherent high demand on computational resources, conditional stability of the solution process, and lack of knowledge of viable parameter range for detailed optimization studies. The absorbable energy monitoring scheme (AEMS) presented in this paper suggests a new design protocol that attempts to overcome such problems in evaluation of vehicle structure for crashworthiness. The implementation of the AEMS involves studying crash performance of vehicle components at various absorbable energy ratios based on a 2DOF lumped-mass-spring (LMS) vehicle impact model. This allows for prompt prediction of useful parameter values in a given design problem. The application of the classical one-dimensional LMS model in vehicle crash analysis is further improved in the present work by developing a critical load matching criterion which allows for quantitative interpretation of the results of the abstract model in a typical vehicle crash design. The adequacy of the proposed AEMS for preliminary vehicle crashworthiness design is demonstrated in this paper, however its extension to full-scale design-optimization problem involving full vehicle model that shows greater structural detail requires more theoretical development.

  11. High temperature underground thermal energy storage system for solar energy

    NASA Astrophysics Data System (ADS)

    Collins, R. E.

    1980-08-01

    The activities feasibility of high temperature underground thermal storage of energy was investigated. Results indicate that salt cavern storage of hot oil is both technically and economically feasible as a method of storing huge quantities of heat at relatively low cost. One particular system identified utilizes a gravel filled cavern leached within a salt dome. Thermal losses are shown to be less than one percent of cyclically transferred heat. A system like this having a 40 MW sub t transfer rate capability and over eight hours of storage capacity is shown to cost about $13.50 per KWh sub t.

  12. High temperature underground thermal energy storage system for solar energy

    NASA Technical Reports Server (NTRS)

    Collins, R. E.

    1980-01-01

    The activities feasibility of high temperature underground thermal storage of energy was investigated. Results indicate that salt cavern storage of hot oil is both technically and economically feasible as a method of storing huge quantities of heat at relatively low cost. One particular system identified utilizes a gravel filled cavern leached within a salt dome. Thermal losses are shown to be less than one percent of cyclically transferred heat. A system like this having a 40 MW sub t transfer rate capability and over eight hours of storage capacity is shown to cost about $13.50 per KWh sub t.

  13. An energy absorbing far-field boundary condition for the elastic wave equation

    SciTech Connect

    Petersson, N A; Sjogreen, B

    2008-07-15

    The authors present an energy absorbing non-reflecting boundary condition of Clayton-Engquist type for the elastic wave equation together with a discretization which is stable for any ratio of compressional to shear wave speed. They prove stability for a second order accurate finite-difference discretization of the elastic wave equation in three space dimensions together with a discretization of the proposed non-reflecting boundary condition. The stability proof is based on a discrete energy estimate and is valid for heterogeneous materials. The proof includes all six boundaries of the computational domain where special discretizations are needed at the edges and corners. The stability proof holds also when a free surface boundary condition is imposed on some sides of the computational domain.

  14. Experimental Investigation of the Power Generation Performance of Floating-Point Absorber Wave Energy Systems: Preprint

    SciTech Connect

    Li, Y.; Yu, Y.; Epler, J.; Previsic, M.

    2012-04-01

    The extraction of energy from ocean waves has gained interest in recent years. The floating-point absorber (FPA) is one of the most promising devices among a wide variety of wave energy conversion technologies. Early theoretical studies mainly focused on understanding the hydrodynamics of the system and on predicting the maximum power that could be extracted by a heaving body. These studies evolve from the investigation of floating-body interactions in offshore engineering and naval architecture disciplines. To our best knowledge, no systematic study has been reported about the investigation of the power generation performance of an FPA with a close-to-commercial design. A series of experimental tests was conducted to investigate the power extraction performance of an FPA system.

  15. Thermally-Resilient, Broadband Optical Absorber from UV-to-IR Derived from Carbon Nanostructures and Method of Making the Same

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B. (Inventor); Coles, James B. (Inventor)

    2015-01-01

    A monolithic optical absorber and methods of making same. The monolithic optical absorber uses an array of mutually aligned carbon nanotubes that are grown using a PECVD growth process and a structure that includes a conductive substrate, a refractory template layer and a nucleation layer. Monolithic optical absorbers made according to the described structure and method exhibit high absorptivity, high site densities (greater than 10.sup.9 nanotubes/cm.sup.2), very low reflectivity (below 1%), and high thermal stability in air (up to at least 400.degree. C.). The PECVD process allows the application of such absorbers in a wide variety of end uses.

  16. Lumbar load attenuation for rotorcraft occupants using a design methodology for the seat impact energy-absorbing system

    NASA Astrophysics Data System (ADS)

    Moradi, Rasoul; Beheshti, Hamid; Lankarani, Hamid

    2012-12-01

    Aircraft occupant crash-safety considerations require a minimum cushion thickness to limit the relative vertical motion of the seat-pelvis during high vertical impact loadings in crash landings or accidents. In military aircraft and helicopter seat design, due to the potential for high vertical accelerations in crash scenarios, the seat system must be provided with an energy absorber to attenuate the acceleration level sustained by the occupants. Because of the limited stroke available for the seat structure, the design of the energy absorber becomes a trade-off problem between minimizing the stroke and maximizing the energy absorption. The available stroke must be used to prevent bottoming out of the seat as well as to absorb maximum impact energy to protect the occupant. In this study, the energy-absorbing system in a rotorcraft seat design is investigated using a mathematical model of the occupant/seat system. Impact theories between interconnected bodies in multibody mechanical systems are utilized to study the impact between the seat pan and the occupant. Experimental responses of the seat system and the occupant are utilized to validate the results from this study for civil and military helicopters according to FAR 23 and 25 and MIL-S-58095 requirements. A model for the load limiter is proposed to minimize the lumbar load for the occupant by minimizing the relative velocity between the seat pan and the occupant's pelvis. The modified energy absorber/load limiter is then implemented for the seat structure so that it absorbs the energy of impact in an effective manner and below the tolerable limit for the occupant in a minimum stroke. Results show that for a designed stroke, the level of occupant lumbar spine injury would be significantly attenuated using this modified energy-absorber system.

  17. Thermal stress depletes energy reserves in Drosophila

    PubMed Central

    Klepsatel, Peter; Gáliková, Martina; Xu, Yanjun; Kühnlein, Ronald P.

    2016-01-01

    Understanding how environmental temperature affects metabolic and physiological functions is of crucial importance to assess the impacts of climate change on organisms. Here, we used different laboratory strains and a wild-caught population of the fruit fly Drosophila melanogaster to examine the effect of temperature on the body energy reserves of an ectothermic organism. We found that permanent ambient temperature elevation or transient thermal stress causes significant depletion of body fat stores. Surprisingly, transient thermal stress induces a lasting “memory effect” on body fat storage, which also reduces survivorship of the flies upon food deprivation later after stress exposure. Functional analyses revealed that an intact heat-shock response is essential to protect flies from temperature-dependent body fat decline. Moreover, we found that the temperature-dependent body fat reduction is caused at least in part by apoptosis of fat body cells, which might irreversibly compromise the fat storage capacity of the flies. Altogether, our results provide evidence that thermal stress has a significant negative impact on organismal energy reserves, which in turn might affect individual fitness. PMID:27641694

  18. Thermal stress depletes energy reserves in Drosophila.

    PubMed

    Klepsatel, Peter; Gáliková, Martina; Xu, Yanjun; Kühnlein, Ronald P

    2016-09-19

    Understanding how environmental temperature affects metabolic and physiological functions is of crucial importance to assess the impacts of climate change on organisms. Here, we used different laboratory strains and a wild-caught population of the fruit fly Drosophila melanogaster to examine the effect of temperature on the body energy reserves of an ectothermic organism. We found that permanent ambient temperature elevation or transient thermal stress causes significant depletion of body fat stores. Surprisingly, transient thermal stress induces a lasting "memory effect" on body fat storage, which also reduces survivorship of the flies upon food deprivation later after stress exposure. Functional analyses revealed that an intact heat-shock response is essential to protect flies from temperature-dependent body fat decline. Moreover, we found that the temperature-dependent body fat reduction is caused at least in part by apoptosis of fat body cells, which might irreversibly compromise the fat storage capacity of the flies. Altogether, our results provide evidence that thermal stress has a significant negative impact on organismal energy reserves, which in turn might affect individual fitness.

  19. Experimental and Analytical Evaluation of a Composite Honeycomb Deployable Energy Absorber

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Kellas, Sotiris; Horta, Lucas G.; Annett, Martin S.; Polanco, Michael A.; Littell, Justin D.; Fasanella, Edwin L.

    2011-01-01

    In 2006, the NASA Subsonic Rotary Wing Aeronautics Program sponsored the experimental and analytical evaluation of an externally deployable composite honeycomb structure that is designed to attenuate impact energy during helicopter crashes. The concept, which is designated the Deployable Energy Absorber (DEA), utilizes an expandable Kevlar honeycomb structure to dissipate kinetic energy through crushing. The DEA incorporates a unique flexible hinge design that allows the honeycomb to be packaged and stowed flat until needed for deployment. A variety of deployment options such as linear, radial, and/or hybrid methods can be used. Experimental evaluation of the DEA utilized a building block approach that included material characterization testing of its constituent, Kevlar -129 fabric/epoxy, and flexural testing of single hexagonal cells. In addition, the energy attenuation capabilities of the DEA were demonstrated through multi-cell component dynamic crush tests, and vertical drop tests of a composite fuselage section, retrofitted with DEA blocks, onto concrete, water, and soft soil. During each stage of the DEA evaluation process, finite element models of the test articles were developed and simulations were performed using the explicit, nonlinear transient dynamic finite element code, LS-DYNA. This report documents the results of the experimental evaluation that was conducted to assess the energy absorption capabilities of the DEA.

  20. Methods for absorbing neutrons

    DOEpatents

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  1. Maximizing Thermal Efficiency and Optimizing Energy Management (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    Researchers at the Thermal Test Facility (TTF) on the campus of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, are addressing maximizing thermal efficiency and optimizing energy management through analysis of efficient heating, ventilating, and air conditioning (HVAC) strategies, automated home energy management (AHEM), and energy storage systems.

  2. Conversion of concentrated solar thermal energy into chemical energy.

    PubMed

    Tamaura, Yutaka

    2012-01-01

    When a concentrated solar beam is irradiated to the ceramics such as Ni-ferrite, the high-energy flux in the range of 1500-2500 kW/m(2) is absorbed by an excess Frenkel defect formation. This non-equilibrium state defect is generated not by heating at a low heating-rate (30 K/min), but by irradiating high flux energy of concentrated solar beam rapidly at a high heating rate (200 K/min). The defect can be spontaneously converted to chemical energy of a cation-excess spinel structure (reduced-oxide form) at the temperature around 1773 K. Thus, the O(2) releasing reaction (α-O(2) releasing reaction) proceeds in two-steps; (1) high flux energy of concentrated solar beam absorption by formation of the non-equilibrium Frenkel defect and (2) the O(2) gas formation from the O(2-) in the Frenkel defect even in air atmosphere. The 2nd step proceeds without the solar radiation. We may say that the 1st step is light reaction, and 2nd step, dark reaction, just like in photosynthesis process.

  3. Attenuation of Scattered Thermal Energy Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce a.; Seroka, Katelyn T.; McPhate, Jason B.; Miller, Sharon K.

    2011-01-01

    The attenuation of scattered thermal energy atomic oxygen is relevant to the potential damage that can occur within a spacecraft which sweeps through atomic oxygen in low Earth orbit (LEO). Although there can be significant oxidation and resulting degradation of polymers and some metals on the external surfaces of spacecraft, there are often openings on a spacecraft such as telescope apertures, vents, and microwave cavities that can allow atomic oxygen to enter and scatter internally to the spacecraft. Atomic oxygen that enters a spacecraft can thermally accommodate and scatter to ultimately react or recombine on surfaces. The atomic oxygen that does enter a spacecraft can be scavenged by use of high erosion yield polymers to reduce its reaction on critical surfaces and materials. Polyoxymethylene and polyethylene can be used as effective atomic oxygen scavenging polymers.

  4. Study on preparation of the core-nanoshell composite absorbers by high-energy ball milling at room temperature.

    PubMed

    Che, Ruxin; Gao, Hong; Yu, Bing; Wang, Shuo; Wang, Chunxia

    2012-02-01

    Electromagnetic (EM) wave pollution has become the chief physical pollution for environment. In recent years, some researches have been focused on the preparation of nano-composite absorbers at low temperatures or even at room temperature. In this letter, preparation of nanocomposite by using high-energy ball milling at room temperature is reported. The core-nanoshell composite absorbers with magnetic fly-ash hollow cenosphere (MFHC) as nuclear and nanocrystalline magnetic material as shell were prepared by high-energy ball milling and vacuum-sintering in this paper. The pre-treatment of MFHC, the sintering process and the mol ratio of starting chemicals had a significant impact for property of composite absorbers. The results of X-ray diffraction analysis (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA) analysis indicated that perfect-crystalline nanomagnetic material coating was gotten with a particle size of 12 nm after ball milling. The results show the MFHC is dielectric loss and magnetic loss too; the exchange-coupling interaction happened between ferrite of the MFHC and nanocrystalline magnetic material coating. The exchange-coupling interaction enhances magnetic loss of composite absorbers. They have a perfect EM parameters at low microwave frequency. The core-nanoshell composite absorbers have a higher magnetic loss at low frequencies, and it is consistent with requirements of the microwave absorbing material at the low-frequency absorption. The microwave absorptivity of the core-nanoshell composite absorbers is better than single material.

  5. Methods for applying microchannels to separate methane using liquid absorbents, especially ionic liquid absorbents from a mixture comprising methane and nitrogen

    DOEpatents

    Tonkovich, Anna Lee Y.; Litt, Robert D.; Dongming, Qiu; Silva, Laura J.; Lamont, Micheal Jay; Fanelli, Maddalena; Simmons, Wayne W.; Perry, Steven

    2011-10-04

    Methods of using microchannel separation systems including absorbents to improve thermal efficiency and reduce parasitic power loss. Energy is typically added to desorb methane and then energy or heat is removed to absorb methane using a working solution. The working solution or absorbent may comprise an ionic liquid, or other fluids that demonstrate a difference in affinity between methane and nitrogen in a solution.

  6. Levelized cost of energy (LCOE) metric to characterize solar absorber coatings for the CSP industry

    DOE PAGES

    Boubault, Antoine; Ho, Clifford K.; Hall, Aaron; ...

    2015-07-08

    The contribution of each component of a power generation plant to the levelized cost of energy (LCOE) can be estimated and used to increase the power output while reducing system operation and maintenance costs. The LCOE is used in order to quantify solar receiver coating influence on the LCOE of solar power towers. Two new parameters are introduced: the absolute levelized cost of coating (LCOC) and the LCOC efficiency. Depending on the material properties, aging, costs, and temperature, the absolute LCOC enables quantifying the cost-effectiveness of absorber coatings, as well as finding optimal operating conditions. The absolute LCOC is investigatedmore » for different hypothetic coatings and is demonstrated on Pyromark 2500 paint. Results show that absorber coatings yield lower LCOE values in most cases, even at significant costs. Optimal reapplication intervals range from one to five years. At receiver temperatures greater than 700 °C, non-selective coatings are not always worthwhile while durable selective coatings consistently reduce the LCOE—up to 12% of the value obtained for an uncoated receiver. Moreover the absolute LCOC is a powerful tool to characterize and compare different coatings, not only considering their initial efficiencies but also including their durability.« less

  7. Levelized cost of energy (LCOE) metric to characterize solar absorber coatings for the CSP industry

    SciTech Connect

    Boubault, Antoine; Ho, Clifford K.; Hall, Aaron; Lambert, Timothy N.; Ambrosini, Andrea

    2015-07-08

    The contribution of each component of a power generation plant to the levelized cost of energy (LCOE) can be estimated and used to increase the power output while reducing system operation and maintenance costs. The LCOE is used in order to quantify solar receiver coating influence on the LCOE of solar power towers. Two new parameters are introduced: the absolute levelized cost of coating (LCOC) and the LCOC efficiency. Depending on the material properties, aging, costs, and temperature, the absolute LCOC enables quantifying the cost-effectiveness of absorber coatings, as well as finding optimal operating conditions. The absolute LCOC is investigated for different hypothetic coatings and is demonstrated on Pyromark 2500 paint. Results show that absorber coatings yield lower LCOE values in most cases, even at significant costs. Optimal reapplication intervals range from one to five years. At receiver temperatures greater than 700 °C, non-selective coatings are not always worthwhile while durable selective coatings consistently reduce the LCOE—up to 12% of the value obtained for an uncoated receiver. Moreover the absolute LCOC is a powerful tool to characterize and compare different coatings, not only considering their initial efficiencies but also including their durability.

  8. High shear rate flow in a linear stroke magnetorheological energy absorber

    NASA Astrophysics Data System (ADS)

    Hu, W.; Wereley, N. M.; Hiemenz, G. J.; Ngatu, G. T.

    2014-05-01

    To provide adaptive stroking load in the crew seats of ground vehicles to protect crew from blast or impact loads, a magnetorheological energy absorber (MREA) or shock absorber was developed. The MREA provides appropriate levels of controllable stroking load for different occupant weights and peak acceleration because the viscous stroking load generated by the MREA force increases with velocity squared, thereby reducing its controllable range at high piston velocity. Therefore, MREA behavior at high piston velocity is analyzed and validated experimentally in order to investigate the effects of velocity and magnetic field on MREA performance. The analysis used to predict the MREA force as a function of piston velocity squared and applied field is presented. A conical fairing is mounted to the piston head of the MREA in order reduce predicted inlet flow loss by 9% at nominal velocity of 8 m/s, which resulted in a viscous force reduction of nominally 4%. The MREA behavior is experimentally measured using a high speed servo-hydraulic testing system for speeds up to 8 m/s. The measured MREA force is used to validate the analysis, which captures the transient force quite accurately, although the peak force is under-predicted at the peak speed of 8 m/s.

  9. Multi-Terrain Impact Testing and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Lyle, Karen H.; Sparks, Chad E.; Sareen, Ashish K.

    2004-01-01

    Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.

  10. Multi-Terrain Impact Testing and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Lyle, Karen H.; Sparks, Chad E.; Sareen, Ashish K.

    2007-01-01

    Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.

  11. A fail-safe magnetorheological energy absorber for shock and vibration isolation

    NASA Astrophysics Data System (ADS)

    Bai, Xian-Xu; Wereley, Norman M.

    2014-05-01

    Magnetorheological (MR) energy absorbers (EAs) are an effective adaptive EA technology with which to maximize shock and vibration isolation. However, to realize maximum performance of the semi-active control system, the off-state (i.e., field off) stroking load of the MREA must be minimized at all speeds, and the dynamic range of the MREA must be maximized at high speed. This study presents a fail-safe MREA (MREA-FS) concept that, can produce a greater dynamic range at all piston speeds. A bias damping force is generated in the MREA-FS using permanent magnetic fields, which enables fail-safe behavior in the case of power failure. To investigate the feasibility and capability of the MREA-FS in the context of the semi-active control systems, a single-degree-of-freedom base excited rigid payload is mathematically constructed and simulated with skyhook control.

  12. A fail-safe magnetorheological energy absorber for shock and vibration isolation

    SciTech Connect

    Bai, Xian-Xu; Wereley, Norman M.

    2014-05-07

    Magnetorheological (MR) energy absorbers (EAs) are an effective adaptive EA technology with which to maximize shock and vibration isolation. However, to realize maximum performance of the semi-active control system, the off-state (i.e., field off) stroking load of the MREA must be minimized at all speeds, and the dynamic range of the MREA must be maximized at high speed. This study presents a fail-safe MREA (MREA-FS) concept that, can produce a greater dynamic range at all piston speeds. A bias damping force is generated in the MREA-FS using permanent magnetic fields, which enables fail-safe behavior in the case of power failure. To investigate the feasibility and capability of the MREA-FS in the context of the semi-active control systems, a single-degree-of-freedom base excited rigid payload is mathematically constructed and simulated with skyhook control.

  13. Development of Lead Free Energy Absorber for Space Shuttle Blast Container

    NASA Technical Reports Server (NTRS)

    Balles, Donald; Ingram, Thomas; Novak, Howard; Schricker, Albert

    1999-01-01

    The Space Shuttle is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the Space Shuttle and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the blast container for two specific reasons: (1) To eliminate lead for environmental concerns, and (2) To reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hang-ups. This upgrade will replace the lead liner with a unique open cell aluminum foam material, that has commercial and military uses. The aluminum foam used as an energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: (1) Lead handling / exposure and possible contamination, along with hazardous waste disposal, will be eliminated; (2) Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam instead of lead; (3) The new aluminum liner is designed to catch all shrapnel from frangible nuts, thus virtually eliminating chance of debris exiting the HDP and causing potential damage to the vehicle; (4) Using the lighter aluminum liner instead of lead, allows for easier assembly and disassembly of blast container elements, which also improves safety, operator handling, and the efficiency of operations.

  14. Crash Test of an MD-500 Helicopter with a Deployable Energy Absorber Concept

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Jackson, Karen E.; Kellas, Sotiris

    2010-01-01

    On December 2, 2009, a full scale crash test was successfully conducted of a MD-500 helicopter at the NASA Langley Research Center Landing and Impact Research Facility . The purpose of this test was to evaluate a novel composite honeycomb deployable energy absorbing (DEA) concept for attenuation of structural and crew loads during helicopter crashes under realistic crash conditions. The DEA concept is an alternative to external airbags, and absorbs impact energy through crushing. In the test, the helicopter impacted the concrete surface with 11.83 m/s (38.8 ft/s) horizontal, 7.80 m/s (25.6 ft/s) vertical and 0.15 m/s (0.5 ft/s) lateral velocities; corresponding to a resultant velocity of 14.2 m/s (46.5 ft/s). The airframe and skid gear were instrumented with accelerometers and strain gages to determine structural integrity and load attenuation, while the skin of the airframe was covered with targets for use by photogrammetry to record gross vehicle motion before, during, and after the impact. Along with the collection of airframe data, one Hybrid III 50th percentile anthropomorphic test device (ATD), two Hybrid II 50th percentile ATDs and a specialized human surrogate torso model (HSTM) occupant were seated in the airframe and instrumented for the collection of occupant loads. Resultant occupant data showed that by using the DEA, the loads on the Hybrid II and Hybrid III ATDs were in the Low Risk regime for the injury criteria, while structural data showed the airframe retained its structural integrity post crash. Preliminary results show that the DEA is a viable concept for the attenuation of impact loads.

  15. Development of Lead Free Energy Absorber for Space Shuttle Blast Container

    NASA Technical Reports Server (NTRS)

    Balles, Donald; Ingram, Thomas; Novak, Howard; Schricker, Albert

    1998-01-01

    The Space Shuttle is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the Space Shuttle and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the blast container for two specific reasons: (1) To eliminate lead for environmental concerns, and (2) To reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hang-ups. This upgrade will replace the lead liner with a unique open cell aluminum foam material, that has commercial and military uses. The aluminum foam used as an energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: (A) Lead handling/exposure and possible contamination, along with hazardous waste disposal, will be eliminated; (B) Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam instead of lead; (C) The new aluminum liner is designed to catch all shrapnel from frangible nuts, thus virtually eliminating chance of debris exiting the HDP and causing potential damage to the vehicle; and (D) Using the lighter aluminum liner instead of lead, allows for easier assembly and disassembly of blast container elements, which also improves safety, operator handling, and the efficiency of operations.

  16. Experimental Results From the Thermal Energy Storage-1 (TES-1) Flight Experiment

    NASA Technical Reports Server (NTRS)

    Jacqmin, David

    1995-01-01

    The Thermal Energy Storage (TES) experiments are designed to provide data to help researchers understand the long-duration microgravity behavior of thermal energy storage fluoride salts that undergo repeated melting and freezing. Such data, which have never been obtained before, have direct application to space-based solar dynamic power systems. These power systems will store solar energy in a thermal energy salt, such as lithium fluoride (LiF) or a eutectic of lithium fluoride/calcium difluoride (LiF-CaF2) (which melts at a lower temperature). The energy will be stored as the latent heat of fusion when the salt is melted by absorbing solar thermal energy. The stored energy will then be extracted during the shade portion of the orbit, enabling the solar dynamic power system to provide constant electrical power over the entire orbit. Analytical computer codes have been developed to predict the performance of a spacebased solar dynamic power system. However, the analytical predictions must be verified experimentally before the analytical results can be used for future space power design applications. Four TES flight experiments will be used to obtain the needed experimental data. This article focuses on the flight results from the first experiment, TES-1, in comparison to the predicted results from the Thermal Energy Storage Simulation (TESSIM) analytical computer code.

  17. Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams

    SciTech Connect

    Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; Bentsen, G.S.; /Rochester U.

    2011-12-13

    The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

  18. OCEAN THERMAL ENERGY CONVERSION PROGRAMMATIC ENVIRONMENTAL ASSESSMENT

    SciTech Connect

    Sands, M. Dale

    1980-08-01

    Significant achievements in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power in this decade with subsequent large-scale commercialization to follow by the turn of the century. Under U.S. Department of Energy funding, Interstate Electronics has prepared an OTEC Programmatic Environmental Assessment (EA) that considers tne development, demonstration, and commercialization of OTEC power systems. The EA considers several tecnnological designs (open cycle and closed cycle), plant configurations (land-based, moored, and plantship), and power usages (baseload electricity and production of ammonia and aluminum). Potencial environmental impacts, health and safety issues, and a status update of international, federal, and state plans and policies, as they may influence OTEC deployments, are included.

  19. Ocean thermal energy conversion: Perspective and status

    SciTech Connect

    Thomas, A.; Hillis, D.L.

    1990-01-01

    The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully be George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250--400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore-based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed-cycle concept. Cost-effective heat-exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat-transfer augmentation techniques were identified, which promised a reduction on heat-exchanger size and cost. Fresh water was produced by an OTEC open-cycle flash evaporator, using the heat energy in the seawater itself. The current R D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open-cycle process. The 10 MW shore-based, closed-cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power -- both valuable commodities on many tropical islands. The open-cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources. 7 refs.

  20. Ocean thermal energy conversion: Perspective and status

    NASA Astrophysics Data System (ADS)

    Thomas, Anthony; Hillis, David L.

    The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully by George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250 to 400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed cycle concept. Cost effective heat exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat transfer augmentation techniques were identified, which promised a reduction on heat exchanger size and cost. Fresh water was produced by an OTEC open cycle flash evaporator, using the heat energy in the seawater itself. The current R and D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open cycle process. The 10 MW shore-based, closed cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power; both valuable commodities on many tropical islands. The open cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources.

  1. Buck-boost converter for simultaneous semi-active vibration control and energy harvesting for electromagnetic regenerative shock absorber

    NASA Astrophysics Data System (ADS)

    Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

    2014-04-01

    Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.

  2. Commercialization of aquifer thermal energy storage technology

    SciTech Connect

    Hattrup, M.P.; Weijo, R.O.

    1989-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the US Department of Energy's (DOE) Office of Energy Storage and Distribution. The purpose of the study was to develop and screen a list of potential entry market applications for aquifer thermal energy storage (ATES). Several initial screening criteria were used to identify promising ATES applications. These include the existence of an energy availability/usage mismatch, the existence of many similar applications or commercial sites, the ability to utilize proven technology, the type of location, market characteristics, the size of and access to capital investment, and the number of decision makers involved. The in-depth analysis identified several additional screening criteria to consider in the selection of an entry market application. This analysis revealed that the best initial applications for ATES are those where reliability is acceptable, and relatively high temperatures are allowable. Although chill storage was the primary focus of this study, applications that are good candidates for heat ATES were also of special interest. 11 refs., 3 tabs.

  3. District Energy Corporation SW 40th Street Thermal Energy Plant

    SciTech Connect

    Davlin, Thomas

    2014-06-06

    The overall deliverable from the project is the design, construction and commissioning of a detention facility heating and cooling system that minimizes ownership costs and maximizes efficiency (and therefore minimizes environmental impact). The primary deliverables were the proof of concept for the application of geothermal systems for an institutional facility and the ongoing, quarterly system operating data downloads to the Department of Energy . The primary advantage of geothermal based heat pump systems is the higher efficiency of the system compared to a conventional chiller, boiler, cooling tower based system. The higher efficiency results in a smaller environmental foot print and lower energy costs for the detention facility owner, Lancaster County. The higher efficiency for building cooling is primarily due to a more constant compressor condensing temperature with the geothermal well field acting as a thermal “sink” (in place of the conventional system’s cooling tower). In the heating mode, Ground Couple Heat Pump (GCHP) systems benefits from the advantage of a heat pump Coefficient of Performance (COP) of approximately 3.6, significantly better than a conventional gas boiler. The geothermal well field acting as a thermal “source” allows the heat pumps to operate efficiently in the heating mode regardless of ambient temperatures. The well field is partially located in a wetland with a high water table so, over time, the project will be able to identify the thermal loading characteristics of a well field located in a high water table location. The project demonstrated how a large geothermal well field can be installed in a wetland area in an economical and environmentally sound manner. Finally, the SW 40th Street Thermal Energy Plant project demonstrates the benefits of providing domestic hot water energy, as well as space heating, to help balance well filed thermal loading in a cooling dominated application. During the period of August 2012 thru

  4. An investigation into the simultaneous use of a resonator as an energy harvester and a vibration absorber

    NASA Astrophysics Data System (ADS)

    Brennan, M. J.; Tang, B.; Melo, G. Pechoto; Lopes, V.

    2014-02-01

    A mass-spring-damper system is at the core of both a vibration absorber and a harvester of energy from ambient vibrations. If such a device is attached to a structure that has a high impedance, then it will have very little effect on the vibrations of the structure, but it can be used to convert mechanical vibrations into electrical energy (act as an energy harvester). However, if the same device is attached to a structure that has a relatively low impedance, then the device may attenuate the vibrations as it may act as both a vibration absorber and an energy harvester simultaneously. In this paper such a device is discussed. Two situations are considered; the first is when the structure is excited with broadband random excitation and the second is when the structure is excited by a single frequency. The optimum parameters of the device for both energy harvesting and vibration attenuation are discussed for these two cases. For random excitation it is found that if the device is optimized for vibration suppression, then this is also adequate for maximizing the energy absorbed (harvested), and thus a single device can effectively suppress vibration and harvest energy at the same time. For single frequency excitation this is found not to be the case. To maximize the energy harvested, the natural frequency of the system (host structure and absorber) has to coincide with the forcing frequency, but to minimize vibration of the host structure, the natural frequency of the absorber has to coincide with the forcing frequency. In this case, therefore, a single resonator cannot effectively suppress vibration and harvest energy at the same time.

  5. High strength semi-active energy absorbers using shear- and mixedmode operation at high shear rates

    NASA Astrophysics Data System (ADS)

    Becnel, Andrew C.

    This body of research expands the design space of semi-active energy absorbers for shock isolation and crash safety by investigating and characterizing magnetorheological fluids (MRFs) at high shear rates ( > 25,000 1/s) under shear and mixed-mode operation. Magnetorheological energy absorbers (MREAs) work well as adaptive isolators due to their ability to quickly and controllably adjust to changes in system mass or impact speed while providing fail-safe operation. However, typical linear stroking MREAs using pressure-driven flows have been shown to exhibit reduced controllability as impact speed (shear rate) increases. The objective of this work is to develop MREAs that improve controllability at high shear rates by using pure shear and mixed shear-squeeze modes of operation, and to present the fundamental theory and models of MR fluids under these conditions. A proof of concept instrument verified that the MR effect persists in shear mode devices at shear rates corresponding to low speed impacts. This instrument, a concentric cylinder Searle cell magnetorheometer, was then used to characterize three commercially available MRFs across a wide range of shear rates, applied magnetic fields, and temperatures. Characterization results are presented both as flow curves according to established practice, and as an alternate nondimensionalized analysis based on Mason number. The Mason number plots show that, with appropriate correction coefficients for operating temperature, the varied flow curve data can be collapsed to a single master curve. This work represents the first shear mode characterization of MRFs at shear rates over 10 times greater than available with commercial rheometers, as well as the first validation of Mason number analysis to high shear rate flows in MRFs. Using the results from the magnetorheometer, a full scale rotary vane MREA was developed as part of the Lightweight Magnetorheological Energy Absorber System (LMEAS) for an SH-60 Seahawk helicopter

  6. Development of Lead Free Energy Absorber for Space Shuttle Blast Container

    NASA Technical Reports Server (NTRS)

    Ingram, T.; Balles, D.; Schricker, A.; Novak, H.

    1998-01-01

    The Space Shuttle vehicle (SSV) is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers (BC) are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the SSV and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the BC for two specific reasons; 1. to eliminate lead for environmental concerns, and 2. to reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hangups. This upgrade will replace the lead liner with an aluminum foam material. The aluminum foam used as a energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: A. Lead handling/ exposure, and possible contamination, along with hazardous waste disposal will be eliminated; B. Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam over lead; C. The new aluminum liner is designed to catch all shrapnel from frangible nuts thus virtually eliminating chance of foreign object debris (FOD) exiting the HDP, and causing potential damage to the vehicle; D. Potential of using the lighter aluminum liner over lead, allows for easier assembly and disassembly of blast container elements, also allowing for improvements in safety, operator handling, and efficiency of operations. Six BC firing tests will be required to determine if the new liner material will perform in a way to decrease the chance of stud hangups and enhance the ability of the BC to retain blast debris. Testing will be performed at the Kennedy Space Center (KSC) facility known as the Launch Equipment Test Facility (LETF), and will simulate the

  7. Vapor shielding models and the energy absorbed by divertor targets during transient events

    NASA Astrophysics Data System (ADS)

    Skovorodin, D. I.; Pshenov, A. A.; Arakcheev, A. S.; Eksaeva, E. A.; Marenkov, E. D.; Krasheninnikov, S. I.

    2016-02-01

    The erosion of divertor targets caused by high heat fluxes during transients is a serious threat to ITER operation, as it is going to be the main factor determining the divertor lifetime. Under the influence of extreme heat fluxes, the surface temperature of plasma facing components can reach some certain threshold, leading to an onset of intense material evaporation. The latter results in formation of cold dense vapor and secondary plasma cloud. This layer effectively absorbs the energy of the incident plasma flow, turning it into its own kinetic and internal energy and radiating it. This so called vapor shielding is a phenomenon that may help mitigating the erosion during transient events. In particular, the vapor shielding results in saturation of energy (per unit surface area) accumulated by the target during single pulse of heat load at some level Emax. Matching this value is one of the possible tests to verify complicated numerical codes, developed to calculate the erosion rate during abnormal events in tokamaks. The paper presents three very different models of vapor shielding, demonstrating that Emax depends strongly on the heat pulse duration, thermodynamic properties, and evaporation energy of the irradiated target material. While its dependence on the other shielding details such as radiation capabilities of material and dynamics of the vapor cloud is logarithmically weak. The reason for this is a strong (exponential) dependence of the target material evaporation rate, and therefore the "strength" of vapor shield on the target surface temperature. As a result, the influence of the vapor shielding phenomena details, such as radiation transport in the vapor cloud and evaporated material dynamics, on the Emax is virtually completely masked by the strong dependence of the evaporation rate on the target surface temperature. However, the very same details define the amount of evaporated particles, needed to provide an effective shielding to the target, and

  8. Development of thermal energy storage units for spacecraft cryogenic coolers

    NASA Technical Reports Server (NTRS)

    Richter, R.; Mahefkey, E. T.

    1980-01-01

    Thermal Energy Storage Units were developed for storing thermal energy required for operating Vuilleumier cryogenic space coolers. In the course of the development work the thermal characteristics of thermal energy storage material was investigated. By three distinctly different methods it was established that ternary salts did not release fusion energy as determined by ideality at the melting point of the eutectic salt. Phase change energy was released over a relatively wide range of temperature with a large change in volume. This strongly affects the amount of thermal energy that is available to the Vuilleumier cryogenic cooler at its operating temperature range and the amount of thermal energy that can be stored and released during a single storage cycle.

  9. MEMS based pyroelectric thermal energy harvester

    DOEpatents

    Hunter, Scott R; Datskos, Panagiotis G

    2013-08-27

    A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.

  10. Ocean Thermal Energy Conversion Act of 1980

    SciTech Connect

    Not Available

    1980-01-01

    A legislative proposal to develop ocean thermal energy conversion (OTEC) facilities for power generation was the subject of hearings held on April 10 and May 1, 1980. Following the test of S. 2492 are the statements of 20 witnesses and additional materials submitted for consideration. The need for a large-scale demonstration of OTEC and the need for a Federal regulatory, siting, and financial-assistance framework are the major commercialization issues. S. 2492 provides one-stop licensing by treating the facilities as vessels and making them eligible for loan guarantees. The bill complements S. 1430, which deals with the demonstration program. OTEC development in Hawaii has progressed to a second pilot project. (DCK)

  11. Influence of nanoscale temperature rises on photoacoustic generation: Discrimination between optical absorbers based on thermal nonlinearity at high frequency.

    PubMed

    Simandoux, Olivier; Prost, Amaury; Gateau, Jérôme; Bossy, Emmanuel

    2015-03-01

    In this work, we experimentally investigate thermal-based nonlinear photoacoustic generation as a mean to discriminate between different types of absorbing particles. The photoacoustic generation from solutions of dye molecules and gold nanospheres (same optical densities) was detected using a high frequency ultrasound transducer (20 MHz). Photoacoustic emission was observed with gold nanospheres at low fluence for an equilibrium temperature around 4 °C, where the linear photoacoustic effect in water vanishes, highlighting the nonlinear emission from the solution of nanospheres. The photoacoustic amplitude was also studied as a function of the equilibrium temperature from 2 °C to 20 °C. While the photoacoustic amplitude from the dye molecules vanished around 4 °C, the photoacoustic amplitude from the gold nanospheres remained significant over the whole temperature range. Our preliminary results suggest that in the context of high frequency photoacoustic imaging, nanoparticles may be discriminated from molecular absorbers based on nanoscale temperature rises.

  12. Photothermal Spectroscopy of Weakly Absorbing Samples Using a Thermal Wave Phase Shifter.

    DTIC Science & Technology

    1984-06-05

    Code 413 June 5. 1984 800 N. Quincy Street 13. NUMBER OF PAGES Arlington, VA 22217 i MONITORING AGENCY NAME & AORESS(II different from Controlling...be 90% throughout the entire visible spectrum. .. NI In photothermalI or photoacoustic 2 techniques the sample under study is excited with a modulated...imaging are numerous. The fact that besides optical also thermal and in the case of photoacoustics even acoustic properties are involved in the

  13. Development of MEMS based pyroelectric thermal energy harvesters

    SciTech Connect

    Hunter, Scott Robert; Lavrik, Nickolay V; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slobodan; Datskos, Panos G

    2011-01-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  14. Development of MEMS based pyroelectric thermal energy harvesters

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2011-06-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  15. Advanced Thermal Energy Storage: Novel Tuning of Critical Fluctuations for Advanced Thermal Energy Storage

    SciTech Connect

    2011-12-01

    HEATS Project: NAVITASMAX is developing a novel thermal energy storage solution. This innovative technology is based on simple and complex supercritical fluids— substances where distinct liquid and gas phases do not exist, and tuning the properties of these fluid systems to increase their ability to store more heat. In solar thermal storage systems, heat can be stored in NAVITASMAX’s system during the day and released at night—when the sun is not shining—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in NAVITASMAX’s system at night and released to produce electricity during daytime peak-demand hours.

  16. Heat pipe solar receiver with thermal energy storage

    NASA Technical Reports Server (NTRS)

    Zimmerman, W. F.

    1981-01-01

    An HPSR Stirling engine generator system featuring latent heat thermal energy storge, excellent thermal stability and self regulating, effective thermal transport at low system delta T is described. The system was supported by component technology testing of heat pipes and of thermal storage and energy transport models which define the expected performance of the system. Preliminary and detailed design efforts were completed and manufacturing of HPSR components has begun.

  17. Capturing the Energy Absorbing Mechanisms of Composite Structures under Crash Loading

    NASA Astrophysics Data System (ADS)

    Wade, Bonnie

    As fiber reinforced composite material systems become increasingly utilized in primary aircraft and automotive structures, the need to understand their contribution to the crashworthiness of the structure is of great interest to meet safety certification requirements. The energy absorbing behavior of a composite structure, however, is not easily predicted due to the great complexity of the failure mechanisms that occur within the material. Challenges arise both in the experimental characterization and in the numerical modeling of the material/structure combination. At present, there is no standardized test method to characterize the energy absorbing capability of composite materials to aide crashworthy structural design. In addition, although many commercial finite element analysis codes exist and offer a means to simulate composite failure initiation and propagation, these models are still under development and refinement. As more metallic structures are replaced by composite structures, the need for both experimental guidelines to characterize the energy absorbing capability of a composite structure, as well as guidelines for using numerical tools to simulate composite materials in crash conditions has become a critical matter. This body of research addresses both the experimental characterization of the energy absorption mechanisms occurring in composite materials during crushing, as well as the numerical simulation of composite materials undergoing crushing. In the experimental investigation, the specific energy absorption (SEA) of a composite material system is measured using a variety of test element geometries, such as corrugated plates and tubes. Results from several crush experiments reveal that SEA is not a constant material property for laminated composites, and varies significantly with the geometry of the test specimen used. The variation of SEA measured for a single material system requires that crush test data must be generated for a range of

  18. Hot Thermal Storage in a Variable Power, Renewable Energy System

    DTIC Science & Technology

    2014-06-01

    characteristics and may not necessarily be available in all cases. Types of direct heat energy systems include solar thermal, waste heat , and geothermal ...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) This thesis outlines the design of a renewable energy heat generation system with thermal...LEFT BLANK v ABSTRACT This thesis outlines the design of a renewable energy heat generation system with thermal storage for DOD facilities. The

  19. A Computational Approach for Model Update of an LS-DYNA Energy Absorbing Cell

    NASA Technical Reports Server (NTRS)

    Horta, Lucas G.; Jackson, Karen E.; Kellas, Sotiris

    2008-01-01

    NASA and its contractors are working on structural concepts for absorbing impact energy of aerospace vehicles. Recently, concepts in the form of multi-cell honeycomb-like structures designed to crush under load have been investigated for both space and aeronautics applications. Efforts to understand these concepts are progressing from tests of individual cells to tests of systems with hundreds of cells. Because of fabrication irregularities, geometry irregularities, and material properties uncertainties, the problem of reconciling analytical models, in particular LS-DYNA models, with experimental data is a challenge. A first look at the correlation results between single cell load/deflection data with LS-DYNA predictions showed problems which prompted additional work in this area. This paper describes a computational approach that uses analysis of variance, deterministic sampling techniques, response surface modeling, and genetic optimization to reconcile test with analysis results. Analysis of variance provides a screening technique for selection of critical parameters used when reconciling test with analysis. In this study, complete ignorance of the parameter distribution is assumed and, therefore, the value of any parameter within the range that is computed using the optimization procedure is considered to be equally likely. Mean values from tests are matched against LS-DYNA solutions by minimizing the square error using a genetic optimization. The paper presents the computational methodology along with results obtained using this approach.

  20. Experimental validation of a magnetorheological energy absorber design optimized for shock and impact loads

    NASA Astrophysics Data System (ADS)

    Singh, Harinder J.; Hu, Wei; Wereley, Norman M.; Glass, William

    2014-12-01

    A linear stroke adaptive magnetorheological energy absorber (MREA) was designed, fabricated and tested for intense impact conditions with piston velocities up to 8 m s-1. The performance of the MREA was characterized using dynamic range, which is defined as the ratio of maximum on-state MREA force to the off-state MREA force. Design optimization techniques were employed in order to maximize the dynamic range at high impact velocities such that MREA maintained good control authority. Geometrical parameters of the MREA were optimized by evaluating MREA performance on the basis of a Bingham-plastic analysis incorporating minor losses (BPM analysis). Computational fluid dynamics and magnetic FE analysis were conducted to verify the performance of passive and controllable MREA force, respectively. Subsequently, high-speed drop testing (0-4.5 m s-1 at 0 A) was conducted for quantitative comparison with the numerical simulations. Refinements to the nonlinear BPM analysis were carried out to improve prediction of MREA performance.

  1. Simulating the Response of a Composite Honeycomb Energy Absorber. Part 2; Full-Scale Impact Testing

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Annett, Martin S.; Jackson, Karen E.; Polanco, Michael A.

    2012-01-01

    NASA has sponsored research to evaluate an externally deployable composite honeycomb designed to attenuate loads in the event of a helicopter crash. The concept, designated the Deployable Energy Absorber (DEA), is an expandable Kevlar(Registered TradeMark) honeycomb. The DEA has a flexible hinge that allows the honeycomb to be stowed collapsed until needed during an emergency. Evaluation of the DEA began with material characterization of the Kevlar(Registered TradeMark)-129 fabric/epoxy, and ended with a full-scale crash test of a retrofitted MD-500 helicopter. During each evaluation phase, finite element models of the test articles were developed and simulations were performed using the dynamic finite element code, LS-DYNA(Registered TradeMark). The paper will focus on simulations of two full-scale impact tests involving the DEA, a mass-simulator and a full-scale crash of an instrumented MD-500 helicopter. Isotropic (MAT24) and composite (MAT58) material models, which were assigned to DEA shell elements, were compared. Based on simulations results, the MAT58 model showed better agreement with test.

  2. Relative Efficiency of TLD-100 to High Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to 137Cs) dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  3. Relative Efficiency of TLD-100 to Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to (137)Cs dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  4. Specific absorbed fractions of energy at various ages from internal photon sources: 6, Newborn

    SciTech Connect

    Cristy, M.; Eckerman, K.F.

    1987-04-01

    Specific absorbed fraction (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a newborn or 3.4-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs.

  5. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  6. A New HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring

    SciTech Connect

    Weathersby, Stephen; Kosovsky, Michael; Kurita, Nadine; Novokhatski, Alexander; Seeman, John; /SLAC

    2006-09-05

    At high currents and small bunch lengths beam line components in the PEP-II B-factory experience RF induced heating from higher order RF modes (HOMs) produced by scattered intense beam fields. A design for a passive HOM water cooled absorber for the PEP-II low energy ring is presented. This device is situated near HOM producing beamline components such as collimators and provide HOM damping for dipole and quadrupole modes without impacting beam impedance. We optimized the impedance characteristics of the device through the evaluation of absorber effectiveness for specific modes using scattering parameter and wakefield analysis. Operational results are presented and agree very well with the predicted effectiveness.

  7. Vapor shielding models and the energy absorbed by divertor targets during transient events

    SciTech Connect

    Skovorodin, D. I. Arakcheev, A. S.; Pshenov, A. A.; Eksaeva, E. A.; Marenkov, E. D.; Krasheninnikov, S. I.

    2016-02-15

    The erosion of divertor targets caused by high heat fluxes during transients is a serious threat to ITER operation, as it is going to be the main factor determining the divertor lifetime. Under the influence of extreme heat fluxes, the surface temperature of plasma facing components can reach some certain threshold, leading to an onset of intense material evaporation. The latter results in formation of cold dense vapor and secondary plasma cloud. This layer effectively absorbs the energy of the incident plasma flow, turning it into its own kinetic and internal energy and radiating it. This so called vapor shielding is a phenomenon that may help mitigating the erosion during transient events. In particular, the vapor shielding results in saturation of energy (per unit surface area) accumulated by the target during single pulse of heat load at some level E{sub max}. Matching this value is one of the possible tests to verify complicated numerical codes, developed to calculate the erosion rate during abnormal events in tokamaks. The paper presents three very different models of vapor shielding, demonstrating that E{sub max} depends strongly on the heat pulse duration, thermodynamic properties, and evaporation energy of the irradiated target material. While its dependence on the other shielding details such as radiation capabilities of material and dynamics of the vapor cloud is logarithmically weak. The reason for this is a strong (exponential) dependence of the target material evaporation rate, and therefore the “strength” of vapor shield on the target surface temperature. As a result, the influence of the vapor shielding phenomena details, such as radiation transport in the vapor cloud and evaporated material dynamics, on the E{sub max} is virtually completely masked by the strong dependence of the evaporation rate on the target surface temperature. However, the very same details define the amount of evaporated particles, needed to provide an effective shielding

  8. Development of energy-absorbing reaction-sintered Si3N4 surface layers on hot-pressed Si3N4

    NASA Technical Reports Server (NTRS)

    Brennan, J. J.

    1981-01-01

    Energy-absorbing Si3N4 surface layers on dense Si3N4 substrates were formed by in-place nitridation of fine-grained silicon powder. Ballistic impact tests performed on samples with 1-mm thick layers at room temperature and 1370 C showed up to an eightfold increase in the energy necessary to fracture the substrate. For maximum impact resistance, a small amount (about 20 vol %) of residual Si must be present in the reaction-sintered Si3N4 surface layer. Thermal cycling to 1370 C did not affect impact resistance, even though a considerable amount of SiO2 formed within the reaction-sintered Si3N4 layer during cycling. Erosion testing of samples in a Mach 0.8 burner rig at 1370 C resulted in minimal surface recession of the surface layer. Chemically vapor-deposited SiC-coated material similarly tested exhibited no surface recession.

  9. Graphene Ink Laminate Structures on Poly(vinylidene difluoride) (PVDF) for Pyroelectric Thermal Energy Harvesting and Waste Heat Recovery.

    PubMed

    Zabek, Daniel; Seunarine, Kris; Spacie, Chris; Bowen, Chris

    2017-03-15

    Thermal energy can be effectively converted into electricity using pyroelectrics, which act as small scale power generator and energy harvesters providing nanowatts to milliwatts of electrical power. In this paper, a novel pyroelectric harvester based on free-standing poly(vinylidene difluoride) (PVDF) was manufactured that exploits the high thermal radiation absorbance of a screen printed graphene ink electrode structure to facilitate the conversion of the available thermal radiation energy into electrical energy. The use of interconnected graphene nanoplatelets (GNPs) as an electrode enable high thermal radiation absorbance and high electrical conductivity along with the ease of deposition using a screen print technique. For the asymmetric structure, the pyroelectric open-circuit voltage and closed-circuit current were measured, and the harvested electrical energy was stored in an external capacitor. For the graphene ink/PVDF/aluminum system the closed circuit pyroelectric current improves by 7.5 times, the open circuit voltage by 3.4 times, and the harvested energy by 25 times compared to a standard aluminum/PVDF/aluminum system electrode design, with a peak energy density of 1.13 μJ/cm(3). For the pyroelectric device employed in this work, a complete manufacturing process and device characterization of these structures are reported along with the thermal conductivity of the graphene ink. The material combination presented here provides a new approach for delivering smart materials and structures, wireless technologies, and Internet of Things (IoT) devices.

  10. Mathematical modeling of moving boundary problems in thermal energy storage

    NASA Technical Reports Server (NTRS)

    Solomon, A. D.

    1980-01-01

    The capability for predicting the performance of thermal energy storage (RES) subsystems and components using PCM's based on mathematical and physical models is developed. Mathematical models of the dynamic thermal behavior of (TES) subsystems using PCM's based on solutions of the moving boundary thermal conduction problem and on heat and mass transfer engineering correlations are also discussed.

  11. Optimizing Ice Thermal Storage to Reduce Energy Cost

    NASA Astrophysics Data System (ADS)

    Hall, Christopher L.

    Energy cost for buildings is an issue of concern for owners across the U.S. The bigger the building, the greater the concern. A part of this is due to the energy required to cool the building and the way in which charges are set when paying for energy consumed during different times of the day. This study will prove that designing ice thermal storage properly will minimize energy cost in buildings. The effectiveness of ice thermal storage as a means to reduce energy costs lies within transferring the time of most energy consumption from on-peak to off-peak periods. Multiple variables go into the equation of finding the optimal use of ice thermal storage and they are all judged with the final objective of minimizing monthly energy costs. This research discusses the optimal design of ice thermal storage and its impact on energy consumption, energy demand, and the total energy cost. A tool for optimal design of ice thermal storage is developed, considering variables such as chiller and ice storage sizes and charging and discharge times. The simulations take place in a four-story building and investigate the potential of Ice Thermal Storage as a resource in reducing and minimizing energy cost for cooling. The simulations test the effectiveness of Ice Thermal Storage implemented into the four-story building in ten locations across the United States.

  12. The effective absorption cross-section of thermal neutrons in a medium containing strongly or weakly absorbing centres

    NASA Astrophysics Data System (ADS)

    Drozdowicz, Krzysztof; Gabańska, Barbara; Igielski, Andrzej; Krynicka, Ewa; Woźnicka, Urszula

    2003-06-01

    The structure of a heterogeneous system influences diffusion of thermal neutrons. The thermal-neutron absorption in grained media is considered in the paper. A simple theory is presented for a two-component medium treated as grains embedded in the matrix or as a system built of two types of grains (of strongly differing absorption cross-sections). A grain parameter is defined as the ratio of the effective macroscopic absorption cross-section of the heterogeneous medium to the absorption cross-section of the corresponding homogeneous medium (consisting of the same components in the same proportions). The grain parameter depends on the ratio of the absorption cross-sections and contributions of the components and on the size of grains. The theoretical approach has been verified in experiments on prepared dedicated models which have kept required geometrical and physical conditions (silver grains distributed regularly in Plexiglas). The effective absorption cross-sections have been measured and compared with the results of calculations. A very good agreement has been observed. In certain cases the differences between the absorption in the heterogeneous and homogeneous media are very significant. A validity of an extension of the theoretical model on natural, two-component, heterogeneous mixtures has been tested experimentally. Aqueous solutions of boric acid have been used as the strongly absorbing component. Fine- and coarse-grained pure silicon has been used as the second component with well-defined thermal-neutron parameters. Small and large grains of diabase have been used as the second natural component. The theoretical predictions have been confirmed in these experiments.

  13. Prevention of thermal buildup by controlled exterior means and solar energy collectors

    SciTech Connect

    Nevins, R.L.

    1981-09-01

    An illustrative embodiment of the invention discloses a solar energy system for a building. A plurality of interlocked thermally conductive flat solar energy collecting plates form a portion of the building's surface. Each of these plates has a web which is generally perpendicular to the web surface. This web supports a suitable tube which is received in notched rafters. The tube contains working fluid which absorbs thermal energy collected by the plates and transfers it to storage or to air flowing in a duct which is formed in the building or structure between a sheet which is attached to the opposite side of the rafters and the flat solar collecting plates which provide one surface of the building.

  14. Flight experiment of thermal energy storage

    NASA Technical Reports Server (NTRS)

    Namkoong, David

    1989-01-01

    Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. These salts store energy as a heat of fusion, thereby transferring heat to the fluid at constant temperature during shade. The principal feature of fluorides that must be taken into account is the change in volume that occurs with melting and freezing. Salts shrink as they solidify, a change reaching 30 percent for some salts. The location of voids that form as result of the shrinkage is critical when the solar dynamic system reemerges into the sun. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The code is capable of analysis under microgravity as well as 1 g. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity. Each test package will be installed in a Getaway Special container to be carried by the shuttle. The package will be self-contained and independent of shuttle operations other than the initial opening of the container lid and the final closing of the lid. Upon the return of the test package from flight, the TES container will be radiographed and finally partitioned to examine the exact location and shape of the void. Visual inspection of the void and the temperature data during flight will constitute the bases for code verification.

  15. Composite materials for thermal energy storage

    DOEpatents

    Benson, D.K.; Burrows, R.W.; Shinton, Y.D.

    1985-01-04

    A composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These PCM's do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon, siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon, siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.

  16. Composite materials for thermal energy storage

    DOEpatents

    Benson, David K.; Burrows, Richard W.; Shinton, Yvonne D.

    1986-01-01

    The present invention discloses composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These phase change materials do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions, such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.

  17. Feasibility studies of aquifer thermal energy storage

    SciTech Connect

    Hall, S. H.

    1993-01-01

    Determining the feasibility of using aquifer thermal energy storage (ATES) for a particular heating or cooling application is an interdisciplinary effort, requiring (at a minimum) expertise in engineering and hydrology. The feasibility study should proceed in two distinct stages. The first stage, which is limited in scope and detail, is intended to show if an ATES system is technically and economically suited to the application. Focus of this preliminary investigation is on revealing the existence of factors that might weigh heavily against the use of ATES methods, and, in the absence of such factors, on choosing a suitable scale for the ATES plant and well field. The results of the preliminary investigation are used to determine if more detailed investigation--including field studies--are justified, and to facilitate comparing the advantages of ATES to those of other means of providing heating or cooling. The second stage of the feasibility study focuses on detailed aquifer characterization, refinement of engineering design and cost estimates, and economic and environmental risk analysis. The results of this investigation, if favorable, will be used to justify the expense of constructing the ATES system.

  18. Ocean thermal energy conversion: a review

    SciTech Connect

    Yuen, P.C.

    1981-10-01

    The OTEC principle is discussed along with general system and cycle types, specific OTEC designs, OTEC applications, and the ocean thermal resource. The historic development of OTEC is briefly reviewed, and the status of French, Japanese, EUROCEAN, and US programs is assessed. US efforts are detailed and DOE's strategy outlined with OTEC-1 and Mini-OTEC information. Power system components of the more technically advanced closed-cycle OTEC concept are discussed. These include: heat exchangers, corrosion and biofouling countermeasures, working fluids, ammonia power systems, and on-platform seawater systems. Several open-cycle features are also discussed. A critical review is presented of the ocean engineering aspects of OTEC power systems. Major subsystems such as platform, cold water pipe, mooring system, dynamic positioning system, power transmission cable system are assessed for their relationships with the ocean environment and with each other. Nine available studies of OTEC costs are reviewed. Tentative comparisons are made between OTEC and traditional fuel costs, and OTEC products and markets are considered. Possible environmental and social effects of OTEC development are discussed. International, national, and local laws regulating OTEC plants and OTEC energy products are reviewed. Tax incentives, attitudes of the utilities, and additional legislative needs are considered. (LEW)

  19. Composite materials for thermal energy storage: enhancing performance through microstructures.

    PubMed

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-05-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are investigated. The ceramic supporting material is essential for preventing salt leakage and hence provides a solution to the chemical incompatibility issue. The use of graphite gives a significant enhancement on the thermal conductivity of the composite. Analyses suggest that the experimentally observed microstructural development of the composite is associated with the wettability of the salt on the ceramic substrate and that on the thermal conduction enhancer.

  20. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  1. Preliminary investigation into the design of thermally responsive Forster resonance energy transfer colloids

    NASA Astrophysics Data System (ADS)

    Bedford, Monte Scott

    While nuclear imaging techniques (Magnetic Resonance Imaging, Computed Tomography, and Positron Emission Tomography) have proven effective for diagnosis and treatment of disease in the human body, fluorescence-enhanced optical imaging offers additional benefits. Fluorescent imaging provides high resolution with real-time response, persistent lifetime (hours to days), cell targeting, and transdermal penetration with minimal physical encumbrance. Malignant cells can be targeted by absorbance of exogenous fluorescent nanoprobe contrast agents. Imaging is improved by fluorescent enhancement, especially by energy transfer between attached dyes. Also for use against cancer are heat-active treatments, such as hyperthermal, photothermal, and chemothermal therapies. Helpful to these treatments is the thermal response from nanoprobes, within human cells, which provide real-time feedback. The present study investigates the design and feasibility of a nanoprobe molecular device, absorbable into malignant human cells, which provides real-time tracking and thermal response, as indicated by enhanced fluorescence by energy transfer. A poly(propargyl acrylate) colloidal suspension was synthesized. The particles were modified with a triblock copolymer, previously shown to be thermally responsive, and an end-attached fluorescent dye. A second dye was modeled for attachment in subsequent work. When two fluorescent dyes are brought within sufficiently close proximity, and excitation light is supplied, energy can be transferred between dyes to give enhanced fluorescence with a large Stokes shift (increase in wavelength between excitation and emission). The dye pair was modeled for overlap of emission and absorbance wavelengths, and energy transfer was demonstrated with 23% efficiency and a 209 nm Stokes shift. The quantum yield of the donor dye was determined at 70%, and the distance for 50% energy transfer was calculated at 2.9 nm, consistent with reports for similar compounds. When

  2. Anisotropy Enhancement of Thermal Energy Transport in Supported Black Phosphorene.

    PubMed

    Chen, Jige; Chen, Shunda; Gao, Yi

    2016-07-07

    Thermal anisotropy along the basal plane of materials possesses both theoretical importance and application value in thermal transport and thermoelectricity. Though common two-dimensional materials may exhibit in-plane thermal anisotropy when suspended, thermal anisotropy would often disappear when supported on a substrate. In this Letter, we find a strong anisotropy enhancement of thermal energy transport in supported black phosphorene. The chiral preference of energy transport in the zigzag rather than the armchair direction is greatly enhanced by coupling to the substrate, up to a factor of approximately 2-fold compared to the suspended one. The enhancement originates from its puckered lattice structure, where the nonplanar armchair energy transport relies on the out-of-plane corrugation and thus would be hindered by the flexural suppression due to the substrate, while the planar zigzag energy transport is not. As a result, thermal conductivity of supported black phosphorene shows a consistent anisotropy enhancement under different temperatures and substrate coupling strengths.

  3. Thermal noise can facilitate energy conversion by a ratchet system.

    PubMed

    Takagi, F; Hondou, T

    1999-10-01

    Molecular motors in biological systems are expected to use ambient fluctuation. In a recent paper [Phys. Rev. Lett. 80, 5251 (1998)], it was shown that the following question was unanswered: Can thermal noise facilitate energy conversion by ratchet system? We consider it using stochastic energetics, and show that there exist systems where thermal noise helps the energy conversion.

  4. Solar-thermal conversion and thermal energy storage of graphene foam-based composites

    NASA Astrophysics Data System (ADS)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-07-01

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a

  5. Method and apparatus for thermal energy storage. [Patent application

    DOEpatents

    Gruen, D.M.

    1975-08-19

    A method and apparatus for storing energy by converting thermal energy to potential chemically bound energy in which a first metal hydride is heated to dissociation temperature, liberating hydrogen gas which is compressed and reacted with a second metal to form a second metal hydride while releasing thermal energy. Cooling the first metal while warming the second metal hydride to dissociation temperature will reverse the flow of hydrogen gas back to the first metal, releasing additional thermal energy. The method and apparatus are particularly useful for the storage and conversion of thermal energy from solar heat sources and for the utilization of this energy for space heating purposes, such as for homes or offices.

  6. A robust method for determining the absorbed dose to water in a phantom for low-energy photon radiation

    NASA Astrophysics Data System (ADS)

    Schneider, T.

    2011-06-01

    The application of more and more low-energy photon radiation in brachytherapy—either in the form of low-dose-rate radioactive seeds such as Pd-103 or I-125 or in the form of miniature x-ray tubes—has induced greater interest in determining the absorbed dose to water in water in this energy range. As it seems to be hardly feasible to measure the absorbed dose with calorimetric methods in this low energy range, ionometric methods are the preferred choice. However, the determination of the absorbed dose to water in water by ionometric methods is difficult in this energy range. With decreasing energy, the relative uncertainty of the photon cross sections increases and as the mass energy transfer coefficients show a steep gradient, the spectra of the radiation field must be known precisely. In this work two ionometric methods to determine the absorbed dose to water are evaluated with respect to their sensitivity to the uncertainties of the spectra and of the atomic database. The first is the measurement of the air kerma free in air and the application of an MC-based conversion factor to the absorbed dose to water. The second is the determination of the absorbed dose to water by means of an extrapolation chamber as an integral part of a phantom. In the complementing MC-calculations, two assortments of spectra each of which is based on a separate unfolding procedure were used as well as two kinds of databases: the standard PEGS and the recently implemented NIST database of EGSnrc. Experimental results were obtained by using a parallel-plate graphite extrapolation chamber and a free-air chamber. In the case when the water kerma in a phantom is determined from the measurements of air kerma free in air, differences in the order of 10% were found, according to which the database or the kind of spectrum is used. In contrast to this, for the second method, the differences found were about 0.5%.

  7. Impact of improved building thermal efficiency on residential energy demand

    SciTech Connect

    Adams, R.C.; Rockwood, A.D.

    1983-04-01

    The impact of improved building shell thermal efficiency on residential energy demand is explored in a theoretical framework. The important economic literature on estimating the price elasticity of residential energy demand is reviewed. The specification of the residential energy demand model is presented. The data used are described. The empirical estimation of the residential energy demand model is described. (MHR)

  8. Development and testing of a dynamic absorber with corrugated piezoelectric spring for vibration control and energy harvesting applications

    NASA Astrophysics Data System (ADS)

    Harne, R. L.

    2013-04-01

    Vibrational energy harvesting devices are often designed in a manner analogous to classical dynamic vibration absorbers (DVAs). An electromechanical mass-spring system is devised so as to resonate at the frequency most dominant in the environmental vibration spectrum; the consequent device oscillation is converted to a electrical signal which is harnessed for immediate usage or as a charging mechanism for a battery. The DVA is likewise designed but with the intention of inducing substantial inertial influence upon a host structure for vibration control purposes, either to globally dampen the vibration of the main body or, in an undamped configuration to "absorb" the primary system vibration at a single frequency. This paper describes the development of an electromechanical mass-spring-damper which seeks to serve both goals of passive vibration control and energy harvesting. The device utilizes a piezoelectric film spring and a distributed mass layer so as to be suitable for the attenuation of surface vibrations and to convert a portion of the absorbed energy into electric power. The development and design of the device are presented and the results of realistic tests are provided to show both the potentials and the challenges encountered when attempting to superpose the goals of vibration control and energy harvesting.

  9. Open cycle ocean thermal energy conversion system

    DOEpatents

    Wittig, J. Michael

    1980-01-01

    An improved open cycle ocean thermal energy conversion system including a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flowpath of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flowpath and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support therefor and impart a desired flow direction to the steam.

  10. Thermal Energy Storage in Phase Change Material.

    DTIC Science & Technology

    1982-03-01

    Graphs of the exnerimental results follow: tney are groupea in the tree categories: tube cross flow, ricked bed, and tube parallel flow. A. Tube Cross... Riordan , Michael, "Thermal Storage: A Rtsic Guile to the Ptate of the Art", Solar Age, Aril, 1978, P. 10. 5. Telkes, Maria, "Thermal Lner y Storage in

  11. Photoswitchable Molecular Rings for Solar-Thermal Energy Storage.

    PubMed

    Durgun, E; Grossman, Jeffrey C

    2013-03-21

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density or short lifetime in the photoinduced high-energy metastable state, rendering their practical use unfeasible. We present a new approach to the design of chemistries for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, or the type of linkers.

  12. Study of light-absorbing crystal birefringence and electrical modulation mechanisms for coupled thermal-optical effects.

    PubMed

    Zhou, Ji; He, Zhihong; Ma, Yu; Dong, Shikui

    2014-09-20

    This paper discusses Gaussian laser transmission in double-refraction crystal whose incident light wavelength is within its absorption wave band. Two scenarios for coupled radiation and heat conduction are considered: one is provided with an applied external electric field, the other is not. A circular heat source with a Gaussian energy distribution is introduced to present the crystal's light-absorption process. The electromagnetic field frequency domain analysis equation and energy equation are solved to simulate the phenomenon by using the finite element method. It focuses on the influence of different values such as wavelength, incident light intensity, heat transfer coefficient, ambient temperature, crystal thickness, and applied electric field strength. The results show that the refraction index of polarized light increases with the increase of crystal temperature. It decreases as the strength of the applied electric field increases if it is positive. The mechanism of electrical modulation for the thermo-optical effect is used to keep the polarized light's index of refraction constant in our simulation. The quantitative relation between thermal boundary condition and strength of applied electric field during electrical modulation is determined. Numerical results indicate a possible approach to removing adverse thermal effects such as depolarization and wavefront distortion, which are caused by thermal deposition during linear laser absorption.

  13. Impact Testing and Simulation of a Crashworthy Composite Fuselage Section with Energy-Absorbing Seats and Dummies

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2002-01-01

    A 25-ft/s vertical drop test of a composite fuselage section was conducted with two energy-absorbing seats occupied by anthropomorphic dummies to evaluate the crashworthy features of the fuselage section and to determine its interaction with the seats and dummies. The 5-ft diameter fuselage section consists of a stiff structural floor and an energy-absorbing subfloor constructed of Rohacel foam blocks. The experimental data from this test were analyzed and correlated with predictions from a crash simulation developed using the nonlinear, explicit transient dynamic computer code, MSC.Dytran. The anthropomorphic dummies were simulated using the Articulated Total Body (ATB) code, which is integrated into MSC.Dytran.

  14. Impact Testing and Simulation of a Crashworthy Composite Fuselage Section with Energy-Absorbing Seats and Dummies

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2002-01-01

    A 25-ft/s vertical drop test of a composite fuselage section was conducted with two energy-absorbing seats occupied by anthropomorphic dummies to evaluate the crashworthy features of the fuselage section and to determine its interaction with the seats and dummies. The 5-ft. diameter fuselage section consists of a stiff structural floor and an energy-absorbing subfloor constructed of Rohacel foam blocks. The experimental data from this test were analyzed and correlated with predictions from a crash simulation developed using the nonlinear, explicit transient dynamic computer code, MSC.Dytran. The anthropomorphic dummies were simulated using the Articulated Total Body (ATB) code, which is integrated into MSC.Dytran.

  15. Alternative biomass sources for thermal energy generation

    NASA Astrophysics Data System (ADS)

    Steensen, Torge; Müller, Sönke; Dresen, Boris; Büscher, Olaf

    2015-04-01

    of Bottrop-Kirchhellen in the state of North Rhine-Westphalia. This region consists of nature reserves, forests, farmland and a few villages. To present a qualitative comparison between simulated and true biomass volume, we conducted field work by mapping the spatial extent of the desired biomass occurrences in the area. First results indicate a qualitative match of about 75%. Our research highlights the small-scale biomass features that have not been incorporated in previous biomass estimates. With the regular trimming and the accompanied raw material that becomes available, a new sector of thermal energy generation can be outlined. An automated quantification using satellite and GIS data will allow a regular monitoring of the vegetation growth and an assessment of the transport routes and costs as well as the location of the prospective power plants. In the endeavour of creating a sustainable energy supply, these biomass units should not be neglected, especially since the usage of the traditional units is limited due to competing interests in food production and nature conservation.

  16. Building heating and cooling applications thermal energy storage program overview

    NASA Technical Reports Server (NTRS)

    Eissenberg, D. M.

    1980-01-01

    Thermal energy storage technology and development of building heating and cooling applications in the residential and commercial sectors is outlined. Three elements are identified to undergo an applications assessment, technology development, and demonstration. Emphasis is given to utility load management thermal energy system application where the stress is on the 'customer side of the meter'. Thermal storage subsystems for space conditioning and conservation means of increased thermal mass within the building envelope and by means of low-grade waste heat recovery are covered.

  17. 15 K liquid hydrogen thermal Energy Storage Unit for future ESA science missions

    NASA Astrophysics Data System (ADS)

    Borges de Sousa, P.; Martins, D.; Tomás, G.; Barreto, J.; Noite, J.; Linder, M.; Fruchart, D.; de Rango, P.; Haettel, R.; Catarino, I.; Bonfait, G.

    2015-12-01

    A thermal Energy Storage Unit (ESU) using liquid hydrogen has been developed as a solution for absorbing the heat peaks released by the recycling phase of a 300 mK cooler that is a part of the cryogenic chain of one of ESA's new satellites for science missions. This device is capable of storing 400 J of thermal energy between 15 and 16 K by taking advantage of the liquid-to-vapor latent heat of hydrogen in a closed system. This paper describes some results obtained with the development model of the ESU under different configurations and using two types of hydrogen storage: a large expansion volume for ground testing and a much more compact unit, suitable for space applications and that can comply with ESA's mass budget.

  18. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    PubMed

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  19. Thermal energy dissipation and xanthophyll cycles beyond the Arabidopsis model.

    PubMed

    García-Plazaola, José Ignacio; Esteban, Raquel; Fernández-Marín, Beatriz; Kranner, Ilse; Porcar-Castell, Albert

    2012-09-01

    Thermal dissipation of excitation energy is a fundamental photoprotection mechanism in plants. Thermal energy dissipation is frequently estimated using the quenching of the chlorophyll fluorescence signal, termed non-photochemical quenching. Over the last two decades, great progress has been made in the understanding of the mechanism of thermal energy dissipation through the use of a few model plants, mainly Arabidopsis. Nonetheless, an emerging number of studies suggest that this model represents only one strategy among several different solutions for the environmental adjustment of thermal energy dissipation that have evolved among photosynthetic organisms in the course of evolution. In this review, a detailed analysis of three examples highlights the need to use models other than Arabidopsis: first, overwintering evergreens that develop a sustained form of thermal energy dissipation; second, desiccation tolerant plants that induce rapid thermal energy dissipation; and third, understorey plants in which a complementary lutein epoxide cycle modulates thermal energy dissipation. The three examples have in common a shift from a photosynthetically efficient state to a dissipative conformation, a strategy widely distributed among stress-tolerant evergreen perennials. Likewise, they show a distinct operation of the xanthophyll cycle. Expanding the list of model species beyond Arabidopsis will enhance our knowledge of these mechanisms and increase the synergy of the current studies now dispersed over a wide number of species.

  20. Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation

    PubMed Central

    Oka, Hisaki

    2016-01-01

    Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature. PMID:27173144

  1. Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation.

    PubMed

    Oka, Hisaki

    2016-05-13

    Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature.

  2. Low-cost and high-throughput realization of metasurface-based absorber/emitter for thermal-photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Bonakdar, Alireza; Rezaei, Mohsen; Dexheimer, Eric; Mohseni, Hooman

    2015-08-01

    A thermal photovoltaic cell (TPV) is an optical heat engine that can extract energy from an emitter with elevated temperature. In theory, the efficiency of a TPV can reach to 80% by wavelength conversion, yet in practice, only 3.2% efficiency has been achieved. The main physical drawback is to maintain the device operation at very high temperature while managing total solar spectrum absorption and efficient coupling of the narrow-band thermal radiation into the photovoltaic cell. In this vein, utilizing of a nanophotonic structure to undergo the wavelength conversion of solar energy is inevitable. Furthermore, low cost, large area and high throughput realization of such a structure brings TPV beyond the research lab. Simultaneous tailoring of UV/visible and mid-infrared spectrums requires sub-100-nm feature size, which is challenging with conventional photolithography if it is not impossible. We have developed a microsphere deep-UV lithography that can produce minimum feature size of ~ 50 nm at extremely low cost and high throughput. In this work, we demonstrate a metasurface platform fabricated with this lithography technique which has omni-polarization and -angle absorption in visible spectrum and efficient emission at mid-infrared as confirmed both by FDTD simulation and Fourier transform infrared spectroscopy (FTIR) measurement. The developed technique is promising technology to expedite TPV in real-life energy harvesting applications.

  3. Thermal energy storage for industrial waste heat recovery

    NASA Technical Reports Server (NTRS)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    Thermal energy storage systems designed for energy conservation through the recovery, storage, and reuse of industrial process waste heat are reviewed. Consideration is given to systems developed for primary aluminum, cement, the food processing industry, paper and pulp, and primary iron and steel. Projected waste-heat recovery and energy savings are listed for each category.

  4. Buffer thermal energy storage for an air Brayton solar engine

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    The application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine was studied. To demonstrate the effect of buffer thermal energy storage on engine operation, a computer program was written which models the recuperator, receiver, and thermal storage device as finite-element thermal masses. Actual operating or predicted performance data are used for all components, including the rotating equipment. Based on insolation input and a specified control scheme, the program predicts the Brayton engine operation, including flows, temperatures, and pressures for the various components, along with the engine output power. An economic parametric study indicates that the economic viability of buffer thermal energy storage is largely a function of the achievable engine life.

  5. Solar photovoltaic/thermal (hybrid) energy project

    NASA Astrophysics Data System (ADS)

    Sheldon, D. B.

    1981-09-01

    Development of photovoltaic/thermal (PV/T) collectors and residential heat pump systems is reported. Candidate collector and residential heat pump systems were evaluated using the TRNSYS computer program. It is found that combined heat pump and PV array is a promising method for achieving economical solar cooling. Where the cooling load is dominant, exclusively PV collectors rather than PV/T collectors are preferred. Where the heating load is dominant, the thermal component of PV/T collectors makes a significant contribution to heating a residence. PV/T collectors were developed whose combined efficiency approaches the efficiency of a double glazed, exclusively thermal collector. The design and operational problems of air source heat pumps are reviewed. Possible effects of compressor startup transients on PV power system operation are discussed.

  6. Electromagnetic energy, absorption, and Casimir forces: Uniform dielectric media in thermal equilibrium

    NASA Astrophysics Data System (ADS)

    Rosa, F. S. S.; Dalvit, D. A. R.; Milonni, P. W.

    2010-03-01

    The derivation of Casimir forces between dielectrics can be simplified by ignoring absorption, calculating energy changes due to displacements of the dielectrics, and only then admitting absorption by allowing permittivities to be complex. As a first step toward a better understanding of this situation we consider in this article the model of a dielectric as a collection of oscillators, each of which is coupled to a reservoir giving rise to damping and Langevin forces on the oscillators and a noise polarization acting as a source of a fluctuating electromagnetic field in the dielectric. The model leads naturally to expressions for the quantized electric and magnetic fields that are consistent with those obtained in approaches that diagonalize the coupled system of oscillators for the dielectric medium, the reservoir, and the electromagnetic field. It also results in a fluctuation-dissipation relation between the noise polarization and the imaginary part of the permittivity; comparison with the Rytov fluctuation-dissipation relation employed in the well-known Lifshitz theory for the van der Waals (or Casimir) force shows that the Lifshitz theory is actually a classical stochastic electrodynamical theory. The approximate classical expression for the energy density in a band of frequencies at which absorption in a dielectric is negligible is shown to be exact as a spectral thermal equilibrium expectation value in quantum electrodynamic theory. Our main result is the derivation of an expression for the QED energy density of a uniform dispersive, absorbing media in thermal equilibrium. The spectral density of the energy is found to have the same form with or without absorption. We also show how the fluctuation-dissipation theorem ensures a detailed balance of energy exchange between the (absorbing) medium, the reservoir, and the electromagnetic field in thermal equilibrium.

  7. Influence of the electron energy and number of beams on the absorbed dose distributions in radiotherapy of deep seated targets.

    PubMed

    Garnica-Garza, H M

    2014-12-01

    With the advent of compact laser-based electron accelerators, there has been some renewed interest on the use of such charged particles for radiotherapy purposes. Traditionally, electrons have been used for the treatment of fairly superficial lesions located at depths of no more than 4cm inside the patient, but lately it has been proposed that by using very high energy electrons, i.e. those with an energy in the order of 200-250MeV it should be possible to safely reach deeper targets. In this paper, we used a realistic patient model coupled with detailed Monte Carlo simulations of the electron transport in such a patient model to examine the characteristics of the resultant absorbed dose distributions as a function of both the electron beam energy as well as the number of beams for a particular type of treatment, namely, a prostate radiotherapy treatment. Each treatment is modeled as consisting of nine, five or three beam ports isocentrically distributed around the patient. An optimization algorithm is then applied to obtain the beam weights in each treatment plan. It is shown that for this particularly challenging case, both excellent target coverage and critical structure sparing can be obtained for energies in the order of 150MeV and for as few as three treatment ports, while significantly reducing the total energy absorbed by the patient with respect to a conventional megavoltage x-ray treatment.

  8. Applications of thermal energy storage in the cement industry

    NASA Technical Reports Server (NTRS)

    Jaeger, F. A.; Beshore, D. G.; Miller, F. M.; Gartner, E. M.

    1978-01-01

    In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development.

  9. Thermal response and recyclability of poly(stearylacrylate-co-ethylene glycol dimethacrylate) gel as a VOCs absorbent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of absorbent materials for volatile organic compounds (VOCs) is in demand for a variety of environmental applications including protective barriers for VOCs point sources. One of the challenges for the currently available VOCs absorbents is their recyclability. In this study, we syn...

  10. Making Heat Visible: Promoting Energy Conservation Behaviors Through Thermal Imaging.

    PubMed

    Goodhew, Julie; Pahl, Sabine; Auburn, Tim; Goodhew, Steve

    2015-12-01

    Householders play a role in energy conservation through the decisions they make about purchases and installations such as insulation, and through their habitual behavior. The present U.K. study investigated the effect of thermal imaging technology on energy conservation, by measuring the behavioral effect after householders viewed images of heat escaping from or cold air entering their homes. In Study 1 (n = 43), householders who received a thermal image reduced their energy use at a 1-year follow-up, whereas householders who received a carbon footprint audit and a non-intervention control demonstrated no change. In Study 2 (n = 87), householders were nearly 5 times more likely to install draught proofing measures after seeing a thermal image. The effect was especially pronounced for actions that addressed an issue visible in the images. Findings indicate that using thermal imaging to make heat loss visible can promote energy conservation.

  11. Optical theory of partially coherent thin-film energy-absorbing structures for power detectors and imaging arrays.

    PubMed

    Withington, Stafford; Thomas, Christopher N

    2009-06-01

    Free-space power detectors often have energy absorbing structures comprising multilayer systems of patterned thin films. We show that for any system of interacting resistive films, the expectation value of the absorbed power is given by the contraction of two tensor fields: one describes the spatial state of coherence of the incoming radiation, the other the state of coherence to which the detector is sensitive. Equivalently, the natural modes of the optical field scatter power into the natural modes of the detector. We describe a procedure for determining the amplitude, phase, and polarization patterns of a detector's optical modes and their relative responsivities. The procedure gives the state of coherence of the currents flowing in the system and leads to important conceptual insights into the way the pixels of an imaging array interact and extract information from an optical field.

  12. Energy consumption in buildings and female thermal demand

    NASA Astrophysics Data System (ADS)

    Kingma, Boris; van Marken Lichtenbelt, Wouter

    2015-12-01

    Energy consumption of residential buildings and offices adds up to about 30% of total carbon dioxide emissions; and occupant behaviour contributes to 80% of the variation in energy consumption. Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s (ref. ). Standard values for one of its primary variables--metabolic rate--are based on an average male, and may overestimate female metabolic rate by up to 35% (ref. ). This may cause buildings to be intrinsically non-energy-efficient in providing comfort to females. Therefore, we make a case to use actual metabolic rates. Moreover, with a biophysical analysis we illustrate the effect of miscalculating metabolic rate on female thermal demand. The approach is fundamentally different from current empirical thermal comfort models and builds up predictions from the physical and physiological constraints, rather than statistical association to thermal comfort. It provides a substantiation of the thermal comfort standard on the population level and adds flexibility to predict thermal demand of subpopulations and individuals. Ultimately, an accurate representation of thermal demand of all occupants leads to actual energy consumption predictions and real energy savings of buildings that are designed and operated by the buildings services community.

  13. Pulse thermal energy transport/storage system

    DOEpatents

    Weislogel, Mark M.

    1992-07-07

    A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

  14. Aquifer thermal energy storage reference manual: seasonal thermal energy storage program

    SciTech Connect

    Prater, L.S.

    1980-01-01

    This is the reference manual of the Seasonal Thermal Energy Storage (STES) Program, and is the primary document for the transfer of technical information of the STES Program. It has been issued in preliminary form and will be updated periodically to include more technical data and results of research. As the program progresses and new technical data become available, sections of the manual will be revised to incorporate these data. This primary document contains summaries of: the TRW, incorporated demonstration project at Behtel, Alaska, Dames and Moore demonstration project at Stony Brook, New York, and the University of Minnesota demonstration project at Minneapolis-St. Paul, Minnesota; the technical support programs including legal/institutional assessment; economic assessment; environmental assessment; field test facilities; a compendia of existing information; numerical simulation; and non-aquifer STES concepts. (LCL)

  15. Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)

    SciTech Connect

    Demuth, R.B.; Harlow, F.H.

    1980-12-01

    A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling of the rock produces thermal stresses that fracture the rock adjacent to the primary crack, thereby enhancing the heat extraction rate by means of convective transport. The properties of the thermal fracture network vary with position and time. The REX code for high-speed computer was written and used to study the coupled processes of primary-crack flow and lateral thermal fracture heat transport. Calculations for elapsed times of 100 y show that thermal fracture enhancement can double the heat extraction rate over the results from conduction alone. Long-term enhancement predictions depend on data from rock-mechanics studies, which the REX code is prepared to accept as they become available.

  16. Design Considerations of a Solid State Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    Janbozorgi, Mohammad; Houssainy, Sammy; Thacker, Ariana; Ip, Peggy; Ismail, Walid; Kavehpour, Pirouz

    2016-11-01

    With the growing governmental restrictions on carbon emission, renewable energies are becoming more prevalent. A reliable use of a renewable source however requires a built-in storage to overcome the inherent intermittent nature of the available energy. Thermal design of a solid state energy storage has been investigated for optimal performance. The impact of flow regime, laminar vs. turbulent, on the design and sizing of the system is also studied. The implications of low thermal conductivity of the storage material are discussed and a design that maximizes the round trip efficiency is presented. This study was supported by Award No. EPC-14-027 Granted by California Energy Commission (CEC).

  17. Legal and regulatory issues affecting aquifer thermal energy storage

    SciTech Connect

    Hendrickson, P.L.

    1981-10-01

    This document updates and expands the report with a similar title issued in October 1980. This document examines a number of legal and regulatory issues that potentially can affect implementation of the aquifer thermal energy storage (ATES) concept. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.

  18. Thermally driven electrokinetic energy conversion with liquid water microjets

    NASA Astrophysics Data System (ADS)

    Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; Saykally, Richard J.

    2015-11-01

    A goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

  19. The effect of the elliptical ratio on the tubular energy absorber subjected to lateral loading under quasistatic conditions

    NASA Astrophysics Data System (ADS)

    Baroutaji, A.; Olabi, A. G.

    2010-06-01

    Tubular systems are proposed to be used as energy absorber because they are cheap and easy to manufacture; recently some researchers use the elliptical tube as energy absorber. In this work, the influence of elliptical ratio (r =D1/D2) on energy absorption capability and load carrying capacity and stress of mild steel elliptical tubes has been investigated both experimentally and numerically, the experimental analyses conducted by using Zwick Type BT1-FB050TN testing instrument. This machine is universal instrument for performing tensile test and compression test, Fig (1) and bending test and it is consider as an important machine for measuring the mechanical properties of materials and structures. The loading frame consist of two vertical lead screws, a moving crosshead and an upper and lower bearing plate which bears the load of the lead screws. The maximum capacity of the loading frame attached to the table mounted unit is 50KN In this study a velocity between 310mm/min was applied to the moving component to ensure the quasistatic conditions whereas velocities between 0.5mm/min and 15 mm/min have been used by many researchers to simulate the quasi-static lateral compression of tubes between various indenters [1-2]. In addition to the experimental work, computational method using ANSYS is used to predict the loading and response of such tubes where series of models was performed with elliptical ratios ranging from 0.5 to 1.5. Comparison of numerical and experimental forcedeflection response is presented. It has been found that with changing the elliptical ratio of the tube the loaddeflection curve change and this leads to change the energy absorbed by tube, the changing of the geometrical shape of the tube leads to change the volume of this tube and hence the mass. By reducing the elliptical ratio to 0.5 the tube will absorb 43.3% more energy and the system will gain 102% more in terms of specific energy, fig (2).

  20. Smart Building: Decision Making Architecture for Thermal Energy Management.

    PubMed

    Uribe, Oscar Hernández; Martin, Juan Pablo San; Garcia-Alegre, María C; Santos, Matilde; Guinea, Domingo

    2015-10-30

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  1. Smart Building: Decision Making Architecture for Thermal Energy Management

    PubMed Central

    Hernández Uribe, Oscar; San Martin, Juan Pablo; Garcia-Alegre, María C.; Santos, Matilde; Guinea, Domingo

    2015-01-01

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction. PMID:26528978

  2. Seasonal Evolution and Interannual Variability of the Local Solar Energy Absorbed by the Arctic Sea Ice-Ocean System

    NASA Technical Reports Server (NTRS)

    Perovich, Donald K.; Nghiem, Son V.; Markus, Thorsten; Schwieger, Axel

    2007-01-01

    The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(sup -2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(sup -2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup.

  3. High Density Thermal Energy Storage with Supercritical Fluids

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  4. Study on thermal evolution of the CuSe phase in nanoparticle-based absorber layers for solution-processed chalcopyrite photovoltaic devices.

    PubMed

    Seo, Yeong-Hui; Lee, Byung-Seok; Jo, Yejin; Kim, Han-Gyeol; Woo, Kyoohee; Moon, Jooho; Choi, Youngmin; Ryu, Beyong-Hwan; Jeong, Sunho

    2013-08-14

    Nanoparticle-based, solution-processed chalcopyrite photovoltaic devices have drawn tremendous attraction for the realization of low-cost, large-area solar cell applications. In particular, it has been recently demonstrated that the CuSe phase plays a critical role in allowing the formation of device-quality, nanoparticle-based chalcopyrite absorber layers. For further in-depth study, with the aim of understanding the thermal behavior of the CuSe phase that triggers the vigorous densification reaction, a requisite for high-performance chalcopyrite absorber layers, both multiphase (CuSe-phase including) and single-phase (CuSe-phase free) CISe nanoparticles are investigated from the viewpoint of compositional variation and crystalline structural evolution. In addition, with CuSe-phase including CISe particulate layers, the basic restrictions in thermal treatment necessary for activating effectively the CuSe-phase induced densification reaction are suggested, in conjunction with consideration on the thermal decomposition of organic additives that are inevitably incorporated in nanoparticle-based absorber layers.

  5. Preparation of thermal infrared and microwave absorber using SrTiO3/BaFe12O19/polyaniline nanocomposites

    NASA Astrophysics Data System (ADS)

    Hosseini, Seyed Hossein; Zamani, Parisa

    2016-01-01

    In this research, first, SrTiO3 was synthesized as thermal infrared (TIR) absorbent and core and then BaFe12O19 as microwave absorbent was prepared on SrTiO3 via co-precipitation method as first shell. Second, polyaniline (PANI) was coated on SrTiO3/BaFe12O19 NPs (NPs) via in situ polymerization by multi core-shell structures (SrTiO3/BaFe12O19/PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe methods. The TIR absorption and microwave reflection loss of nanocomposites were investigated at 10-40 μm and 8-12 GHz, TIR and microwave frequencies, respectively. The results showed that the SrTiO3/BaFe12O19/PANI nanocomposites have good compatible electric and magnetic properties and hence the microwave absorbency show wide bandwidth properties. The infrared thermal image testing showed that the ability of infrared thermal imaging was increased by increasing SrTiO3/BaFe12O19 as core and independent to increasing PANI as final shell.

  6. Guide to Setting Thermal Comfort Criteria and Minimizing Energy Use in Delivering Thermal Comfort

    SciTech Connect

    Regnier, Cindy

    2012-08-01

    Historically thermal comfort in buildings has been controlled by simple dry bulb temperature settings. As we move into more sophisticated low energy building systems that make use of alternate systems such as natural ventilation, mixed mode system and radiant thermal conditioning strategies, a more complete understanding of human comfort is needed for both design and control. This guide will support building designers, owners, operators and other stakeholders in defining quantifiable thermal comfort parameters?these can be used to support design, energy analysis and the evaluation of the thermal comfort benefits of design strategies. This guide also contains information that building owners and operators will find helpful for understanding the core concepts of thermal comfort. Whether for one building, or for a portfolio of buildings, this guide will also assist owners and designers in how to identify the mechanisms of thermal comfort and space conditioning strategies most important for their building and climate, and provide guidance towards low energy design options and operations that can successfully address thermal comfort. An example of low energy design options for thermal comfort is presented in some detail for cooling, while the fundamentals to follow a similar approach for heating are presented.

  7. Thermal Energy Corporation in Houston, Texas Earns ENERGY STAR Award for Carbon Pollution Reductions

    EPA Pesticide Factsheets

    DALLAS - (June 29, 2015) The U.S. Environmental Protection Agency (EPA) recently recognized Thermal Energy Corporation (TECO) of Houston, Texas with the ENERGY STAR Combined Heat and Power (CHP) Award. TECO substantially reduced emissions of carbon

  8. Rapid charging of thermal energy storage materials through plasmonic heating.

    PubMed

    Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

    2014-09-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites.

  9. Rapid Charging of Thermal Energy Storage Materials through Plasmonic Heating

    PubMed Central

    Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

    2014-01-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites. PMID:25175717

  10. Absorbed doses and energy imparted from radiographic examination of velopharyngeal function during speech

    SciTech Connect

    Isberg, A.; Julin, P.; Kraepelien, T.; Henrikson, C.O. )

    1989-04-01

    Absorbed doses of radiation were measured by thermoluminescent dosimeters (TLDs) using a skull phantom during simulated cinefluorographic and videofluorographic examination of velopharyngeal function in frontal and lateral projections. Dosages to the thyroid gland, the parotid gland, the pituitary gland, and ocular lens were measured. Radiation dosage was found to be approximately 10 times less for videofluoroscopy when compared with that of cinefluoroscopy. In addition, precautionary measures were found to reduce further the exposure of radiation-sensitive tissues. Head fixation and shielding resulted in dose reduction for both video- and cinefluoroscopy. Pulsing exposure for cinefluoroscopy also reduced the dosage.

  11. Photon energy upconversion through thermal radiation with the power efficiency reaching 16%.

    PubMed

    Wang, Junxin; Ming, Tian; Jin, Zhao; Wang, Jianfang; Sun, Ling-Dong; Yan, Chun-Hua

    2014-11-28

    The efficiency of many solar energy conversion technologies is limited by their poor response to low-energy solar photons. One way for overcoming this limitation is to develop materials and methods that can efficiently convert low-energy photons into high-energy ones. Here we show that thermal radiation is an attractive route for photon energy upconversion, with efficiencies higher than those of state-of-the-art energy transfer upconversion under continuous wave laser excitation. A maximal power upconversion efficiency of 16% is achieved on Yb(3+)-doped ZrO2. By examining various oxide samples doped with lanthanide or transition metal ions, we draw guidelines that materials with high melting points, low thermal conductivities and strong absorption to infrared light deliver high upconversion efficiencies. The feasibility of our upconversion approach is further demonstrated under concentrated sunlight excitation and continuous wave 976-nm laser excitation, where the upconverted white light is absorbed by Si solar cells to generate electricity and drive optical and electrical devices.

  12. Thermal effects on isoscalar giant resonance energies in hot nuclei

    SciTech Connect

    Wen, W.; Dai, G.; Jin, G.

    1995-07-01

    The thermal effects on the energies of the isoscalar giant multipole resonances of hot nuclei are discussed and an approximate formula for the energy as a function of temperature is derived via a hydrodynamic theory. The energy difference between the isoscalar giant multipole resonance of a hot nucleus and its ground-state resonance depends on the competition between the volume expansion and the increase of the average kinetic energy per nucleon of hot nuclei, which lower and raise the resonance energy, respectively, and nearly counteract each other in magnitude. The variaiton of the isoscalar giant resonance energy with temperature is very small.

  13. Impact behavior of a high viscosity magnetorheological fluid-based energy absorber with a radial flow mode

    NASA Astrophysics Data System (ADS)

    Fu, Benyuan; Liao, Changrong; Li, Zhuqiang; Xie, Lei; Zhang, Peng; Jian, Xiaochun

    2017-02-01

    High viscosity linear polysiloxane magnetorheological fluid (HVLP MRF) was demonstrated with excellent suspension stability. Such material is suitable for application in the magnetorheological energy absorbers (MREAs) under axial impact loading conditions. On this basis, a new energy absorber incorporating a radial valve with high magnetic field utilization and a corrugated tube is proposed. In energy absorption applications where the MREA is rarely if ever used, our MREA takes the ultra-stable HVLP MRF as controlled medium in order for a long-term stability. For MREA performing at very high shear rates where the minor losses are important contributing factors to damping, a nonlinear analytical model, based on the Herschel-Bulkley flow model (HB model), is developed taking into account the effects of minor losses (called HBM model). The HB model parameters are determined by rheological experiments with a commercial shear rheometer. Then, continuity equation and governing differential equation of the HVLP MRF in radial flow are established. Based on the HB model, the expressions of radial velocity distribution are deduced. The influences of minor losses on pressure drop are analyzed with mean fluid velocities. Further, mechanical behavior of the corrugated tube is investigated via drop test. In order to verify the theoretical methodology, a MREA is fabricated and tested using a high-speed drop tower facility with a 600 kg mass at different drop heights and in various magnetic fields. The experiment results show that the HBM model is capable of well predicting the impact behavior of the proposed MREA.

  14. The Development of a Conical Composite Energy Absorber for Use in the Attenuation of Crash/Impact Loads

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2014-01-01

    A design for a novel light-weight conical shaped energy absorbing (EA) composite subfloor structure is proposed. This composite EA is fabricated using repeated alternating patterns of a conical geometry to form long beam structures which can be implemented as aircraft subfloor keel beams or frame sections. The geometrical features of this conical design, along with the hybrid composite materials used in the manufacturing process give a strength tailored to achieve a constant 25-40 g sustained crush load, small peak crush loads and long stroke limits. This report will discuss the geometrical design and fabrication methods, along with results from static and dynamic crush testing of 12-in. long subcomponents.

  15. ENERGY PARTITIONS AND EVOLUTION IN A PURELY THERMAL SOLAR FLARE

    SciTech Connect

    Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E.

    2015-04-01

    This paper presents a solely thermal flare, which we detected in the microwave range from the thermal gyro- and free–free emission it produced. An advantage of analyzing thermal gyro emission is its unique ability to precisely yield the magnetic field in the radiating volume. When combined with observationally deduced plasma density and temperature, these magnetic field measurements offer a straightforward way of tracking evolution of the magnetic and thermal energies in the flare. For the event described here, the magnetic energy density in the radio-emitting volume declines over the flare rise phase, then stays roughly constant during the extended peak phase, but recovers to the original level over the decay phase. At the stage where the magnetic energy density decreases, the thermal energy density increases; however, this increase is insufficient, by roughly an order of magnitude, to compensate for the magnetic energy decrease. When the magnetic energy release is over, the source parameters come back to nearly their original values. We discuss possible scenarios to explain this behavior.

  16. Magneto-Thermo-Triboelectric Generator (MTTG) for thermal energy harvesting

    NASA Astrophysics Data System (ADS)

    Jang, Kwang Yeop; Lee, James; Lee, Dong-Gun

    2016-04-01

    We present a novel thermal energy harvesting system using triboelectric effect. Recently, there has been intensive research efforts on energy harvesting using triboelectric effect, which can produce surprising amount of electric power (when compared to piezoelectric materials) by rubbing or touching (i.e, electric charge by contact and separation) two different materials together. Numerous studies have shown the possibility as an attractive alternative with good transparency, flexibility and low cost abilities for its use in wearable device and smart phone applications markets. However, its application has been limited to only vibration source, which can produce sustained oscillation with maintaining contact and separation states repeatedly for triboelectric effect. Thus, there has been no attempt toward thermal energy source. The proposed approach can convert thermal energy into electricity by pairing triboelectric effect and active ferromagnetic materials The objective of the research is to develop a new manufacturing process of design, fabrication, and testing of a Magneto-Thermo-Triboelectric Generator (MTTG). The results obtained from the approach show that MTTG devices have a feasible power energy conversion capability from thermal energy sources. The tunable design of the device is such that it has efficient thermal capture over a wide range of operation temperature in waste heat.

  17. Engineering evaluation of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Perdue, D. G.; Gordon, L. H.

    1980-01-01

    An engineering evaluation of thermal energy storage prototypes was performed in order to assess the development status of latent heat storage media. The testing and the evaluation of a prototype sodium hydroxide module is described. This module stored off-peak electrical energy as heat for later conversion to domestic hot water needs.

  18. Ocean thermal energy conversion: report to congress - fiscal year 1982

    SciTech Connect

    Not Available

    1983-03-31

    National Oceanic and Atmospheric Administration (NOAA) activities related to ocean thermal energy conversion (OTEC) during fiscal year 1982 are described. The agency focus has been in the areas of providing ocean engineering and technical assistance to the Department of Energy (DOE), in streamlining the administration of the Federal OTEC licensing system, and in environmental assistance.

  19. Energy Aspects of Thermal Molecular Switching: Molecular Thermal Hysteresis of Helicene Oligomers.

    PubMed

    Shigeno, Masanori; Kushida, Yo; Yamaguchi, Masahiko

    2015-07-20

    Molecular switching is a phenomenon by which a molecule reversibly changes its structure and state in response to external stimuli or energy. Herein, molecular switching is discussed from thermodynamic and kinetic aspects in terms of energy supply with an emphasis on the thermal switching exhibited by helicene oligomers. It includes the inversion of relative thermodynamic stability induced by temperature changes and molecular thermal hysteresis in a closed system. The thermal phenomenon associated with the oligomers involves population/concentration changes between metastable states under nonequilibrium thermodynamic control.

  20. Thermal conductor for high-energy electrochemical cells

    DOEpatents

    Hoffman, Joseph A.; Domroese, Michael K.; Lindeman, David D.; Radewald, Vern E.; Rouillard, Roger; Trice, Jennifer L.

    2000-01-01

    A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

  1. Study of thermal energy storage using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Weast, T. E.; Shannon, L. J.; Ananth, K. P.

    1980-01-01

    The technical and economic feasibility of fluid bed heat exchangers (FBHX) for thermal energy storage (TES) in waste heat recovery applications is assessed by analysis of two selected conceptual systems, the rotary cement kiln and the electric arc furnace. It is shown that the inclusion of TES in the energy recovery system requires that the difference in off-peak and on-peak energy rates be large enough so that the value of the recovered energy exceeds the value of the stored energy by a wide enough margin to offset parasitic power and thermal losses. Escalation of on-peak energy rates due to fuel shortages could make the FBHX/TES applications economically attractive in the future.

  2. Solar thermal parabolic dish energy applications

    NASA Technical Reports Server (NTRS)

    Pijawka, W.

    1981-01-01

    Vu-graphs are presented that show that applications are a viable distributed renewable power generation option. Quality energy can be produced in the form of electricity and high temperature heat. Modular systems are described that can be distributed to new or existing plants and that are mass producible with the associated economies of production.

  3. Energy, Electron Transfer and Photocatalytic Reactions of Visible Light Absorbing Transition Metal Complexes

    SciTech Connect

    Schmehl, Russell H.

    2016-03-02

    This is the final technical report for a project carried out at Tulane University of New Orleans that describes the development of light induced (solar) reactions geared toward decomposing water into its component elements : hydrogen and oxygen. Much of the work involved optimizing systems for absorbing visible light and undergoing light promoted reactions to generate very strong reducing agents that are capable of reacting with water to produce hydrogen. Additional portions of the research were collaborative efforts to put the strong reducing agents to work in reaction with hydrogen generation catalysts prepared elsewhere. Time resolved laser spectroscopic methods were used to evaluate the light induced reactions and characterize very reactive intermediate substances formed during the reactions.

  4. Metal hydrides for concentrating solar thermal power energy storage

    NASA Astrophysics Data System (ADS)

    Sheppard, D. A.; Paskevicius, M.; Humphries, T. D.; Felderhoff, M.; Capurso, G.; Bellosta von Colbe, J.; Dornheim, M.; Klassen, T.; Ward, P. A.; Teprovich, J. A.; Corgnale, C.; Zidan, R.; Grant, D. M.; Buckley, C. E.

    2016-04-01

    The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed.

  5. Alcan's ocean thermal energy conversion (OTEC) program

    SciTech Connect

    Hron, V.; Fitzpatrick, N.P. ); Hay, E. ); Johnson, F.A. )

    1991-01-01

    Since 1985 Alcan has been operating equipment at a test site at the National Energy Laboratory of Hawaii at Keahole Point near Kona in Hawaii. Segments of aluminum heat exchangers are exposed to surface sea water at 27{degrees} C and to water from 2000 ft down coming in at 7{degrees} C. Progress was such that in 1988 Alcan contracted GEC to design a 250 kW pilot facility. The cold deep water, suitable for air conditioning, is rich in nutrients and the hierarchy of mariculture products one might select is outlined. This paper reports that closed-cycle OTEC may be economical, practical and capable of having a significant impact upon world energy needs. It can be implemented on a small scale using revenues derived from fresh water production and mariculture.

  6. Micro rectennas: Brownian ratchets for thermal-energy harvesting

    SciTech Connect

    Pan, Y.; Powell, C. V.; Balocco, C.; Song, A. M.

    2014-12-22

    We experimentally demonstrated the operation of a rectenna for harvesting thermal (blackbody) radiation and converting it into dc electric power. The device integrates an ultrafast rectifier, the self-switching nanodiode, with a wideband log-periodic spiral microantenna. The radiation from the thermal source drives the rectenna out of thermal equilibrium, permitting the rectification of the excess thermal fluctuations from the antenna. The power conversion efficiency increases with the source temperatures up to 0.02% at 973 K. The low efficiency is attributed mainly to the impedance mismatch between antenna and rectifier, and partially to the large field of view of the antenna. Our device not only opens a potential solution for harvesting thermal energy but also provides a platform for experimenting with Brownian ratchets.

  7. Predicting the biological effects of mobile phone radiation absorbed energy linked to the MRI-obtained structure.

    PubMed

    Krstić, Dejan; Zigar, Darko; Petković, Dejan; Sokolović, Dušan; Dinđić, Boris; Cvetković, Nenad; Jovanović, Jovica; Dinđić, Nataša

    2013-01-01

    The nature of an electromagnetic field is not the same outside and inside a biological subject. Numerical bioelectromagnetic simulation methods for penetrating electromagnetic fields facilitate the calculation of field components in biological entities. Calculating energy absorbed from known sources, such as mobile phones when placed near the head, is a prerequisite for studying the biological influence of an electromagnetic field. Such research requires approximate anatomical models which are used to calculate the field components and absorbed energy. In order to explore the biological effects in organs and tissues, it is necessary to establish a relationship between an analogous anatomical model and the real structure. We propose a new approach in exploring biological effects through combining two different techniques: 1) numerical electromagnetic simulation, which is used to calculate the field components in a similar anatomical model and 2) Magnetic Resonance Imaging (MRI), which is used to accurately locate sites with increased absorption. By overlapping images obtained by both methods, we can precisely locate the spots with maximum absorption effects. This way, we can detect the site where the most pronounced biological effects are to be expected. This novel approach successfully overcomes the standard limitations of working with analogous anatomical models.

  8. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    SciTech Connect

    Bakar, Khomsaton Abu; Zulkafli,; Hashim, Siti A'aisah; Ahmad, Pauzi

    2014-09-03

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD{sub 5}, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

  9. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    NASA Astrophysics Data System (ADS)

    Bakar, Khomsaton Abu; Ahmad, Pauzi; Zulkafli, Hashim, Siti A'aisah

    2014-09-01

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD5, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

  10. Buffer thermal energy storage for a solar Brayton engine

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    A study has been completed on the application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine. To aid in the study, a computer program was written for complete transient/stead-state Brayton cycle performance. The results indicated that thermal storage can afford a significant decrease in the number of engine shutdowns as compared to operating without thermal storage. However, the number of shutdowns does not continuously decrease as the storage material weight increases. In fact, there appears to be an optimum weight for minimizing the number of shutdowns.

  11. Diurnal and developmental changes in energy allocation of absorbed light at PSII in field-grown rice.

    PubMed

    Ishida, Satoshi; Uebayashi, Nozomu; Tazoe, Youshi; Ikeuchi, Masahiro; Homma, Koki; Sato, Fumihiko; Endo, Tsuyoshi

    2014-01-01

    The allocation of absorbed light energy in PSII to electron transport and heat dissipation processes in rice grown under waterlogged conditions was estimated with the lake model of energy transfer. With regard to diurnal changes in energy allocation, the peak of the energy flux to electron transport, J(PSII), occurred in the morning and the peak of the energy flux to heat dissipation associated with non-photochemical quenching of Chl fluorescence, J(NPQ), occurred in the afternoon. With regard to seasonal changes in energy allocation, J(PSII) in the rapidly growing phase was greater than that in the ripening phase, even though the leaves of rice receive less light in the growing phase than in the ripening period in Japan. This seasonal decrease in J(PSII) was accompanied by an increase in J(NPQ). One of the reasons for the lower J(PSII) in the ripening phase might be a more sever afternoon suppression of J(PSII). To estimate energy dissipation due to photoinhibition of PSII, J(NPQ) was divided into J(fast), which is associated with fast-recovering NPQ mainly due to qE, and J(slow), which is mainly due to photoinhibition. The integrated daily energy loss by photoinhibiton was calculated to be about 3-8% of light energy absorption in PSII. Strategies for the utilization of light energy adopted by rice are discussed. For example, very efficient photosynthesis under non-saturating light in the rapidly growing phase is proposed.

  12. Thermal energy storage technical progress report, April 1992--March 1993

    SciTech Connect

    Olszewski, M.

    1993-05-01

    The Department of Energy (DOE) is supporting development of thermal energy storage (TES) as a means of efficiently coupling energy supplies to variable heating or cooling demands. Uses of TES include electrical demand-side management in buildings and industry, extending the utilization of renewable energy resources such as solar, and recovery of waste heat from periodic industrial processes. Technical progress to develop TES for specific diurnal and industrial applications under the Oak Ridge National Laboratory`s TES program from April 1992 to March 1993 is reported and covers research in the areas of low temperature sorption, thermal energy storage water heater, latent heat storage wallboard and latent/sensible heat regenerator technology development.

  13. PHITS simulations of absorbed dose out-of-field and neutron energy spectra for ELEKTA SL25 medical linear accelerator

    NASA Astrophysics Data System (ADS)

    Puchalska, Monika; Sihver, Lembit

    2015-06-01

    Monte Carlo (MC) based calculation methods for modeling photon and particle transport, have several potential applications in radiotherapy. An essential requirement for successful radiation therapy is that the discrepancies between dose distributions calculated at the treatment planning stage and those delivered to the patient are minimized. It is also essential to minimize the dose to radiosensitive and critical organs. With MC technique, the dose distributions from both the primary and scattered photons can be calculated. The out-of-field radiation doses are of particular concern when high energy photons are used, since then neutrons are produced both in the accelerator head and inside the patients. Using MC technique, the created photons and particles can be followed and the transport and energy deposition in all the tissues of the patient can be estimated. This is of great importance during pediatric treatments when minimizing the risk for normal healthy tissue, e.g. secondary cancer. The purpose of this work was to evaluate 3D general purpose PHITS MC code efficiency as an alternative approach for photon beam specification. In this study, we developed a model of an ELEKTA SL25 accelerator and used the transport code PHITS for calculating the total absorbed dose and the neutron energy spectra infield and outside the treatment field. This model was validated against measurements performed with bubble detector spectrometers and Boner sphere for 18 MV linacs, including both photons and neutrons. The average absolute difference between the calculated and measured absorbed dose for the out-of-field region was around 11%. Taking into account a simplification for simulated geometry, which does not include any potential scattering materials around, the obtained result is very satisfactorily. A good agreement between the simulated and measured neutron energy spectra was observed while comparing to data found in the literature.

  14. PHITS simulations of absorbed dose out-of-field and neutron energy spectra for ELEKTA SL25 medical linear accelerator.

    PubMed

    Puchalska, Monika; Sihver, Lembit

    2015-06-21

    Monte Carlo (MC) based calculation methods for modeling photon and particle transport, have several potential applications in radiotherapy. An essential requirement for successful radiation therapy is that the discrepancies between dose distributions calculated at the treatment planning stage and those delivered to the patient are minimized. It is also essential to minimize the dose to radiosensitive and critical organs. With MC technique, the dose distributions from both the primary and scattered photons can be calculated. The out-of-field radiation doses are of particular concern when high energy photons are used, since then neutrons are produced both in the accelerator head and inside the patients. Using MC technique, the created photons and particles can be followed and the transport and energy deposition in all the tissues of the patient can be estimated. This is of great importance during pediatric treatments when minimizing the risk for normal healthy tissue, e.g. secondary cancer. The purpose of this work was to evaluate 3D general purpose PHITS MC code efficiency as an alternative approach for photon beam specification. In this study, we developed a model of an ELEKTA SL25 accelerator and used the transport code PHITS for calculating the total absorbed dose and the neutron energy spectra infield and outside the treatment field. This model was validated against measurements performed with bubble detector spectrometers and Boner sphere for 18 MV linacs, including both photons and neutrons. The average absolute difference between the calculated and measured absorbed dose for the out-of-field region was around 11%. Taking into account a simplification for simulated geometry, which does not include any potential scattering materials around, the obtained result is very satisfactorily. A good agreement between the simulated and measured neutron energy spectra was observed while comparing to data found in the literature.

  15. Pyroelectric energy harvesting using liquid-based switchable thermal interfaces

    SciTech Connect

    Cha, G; Ju, YS

    2013-01-15

    The pyroelectric effect offers an intriguing solid-state approach for harvesting ambient thermal energy to power distributed networks of sensors and actuators that are remotely located or otherwise difficult to access. There have been, however, few device-level demonstrations due to challenges in converting spatial temperature gradients into temporal temperature oscillations necessary for pyroelectric energy harvesting. We demonstrate the feasibility of a device concept that uses liquid-based thermal interfaces for rapid switching of the thermal conductance between a pyroelectric material and a heat source/sink and can thereby deliver high output power density. Using a thin film of a pyroelectric co-polymer together with a macroscale mechanical actuator, we operate pyroelectric thermal energy harvesting cycles at frequencies close to 1 Hz. Film-level power densities as high as 110 mW/cm(3) were achieved, limited by slow heat diffusion across a glass substrate. When combined with a laterally interdigitated electrode array and a MEMS actuator, the present design offers an attractive option for compact high-power density thermal energy harvesters. (C) 2012 Elsevier B.V. All rights reserved.

  16. Thermal stability and energy harvesting characteristics of Au nanorods: harsh environment chemical sensing

    NASA Astrophysics Data System (ADS)

    Karker, Nicholas; Dharmalingam, Gnanaprakash; Carpenter, Michael A.

    2015-05-01

    Monitoring the levels of polluting gases such as CO and NOx from high temperature (500°C and higher) combustion environments requires materials with high thermal stability and resilience that can withstand harsh oxidizing and reducing environments. Au nanorods (AuNRs) have shown potential in plasmonic gas sensing due to their catalytic activity, high oxidation stability, and absorbance sensitivity to changes in the surrounding environment. By using electron beam lithography, AuNR geometries can be patterned with tight control of the rod dimensions and spacings, allowing tunability of their optical properties. Methods such as NR encapsulation within an yttria-stabilized zirconia overcoat layer with subsequent annealing procedures will be shown to improve temperature stability within a simulated harsh environment. Since light sources and spectrometers are typically required to obtain optical measurements, integration is a major barrier for harsh environment sensing. Plasmonic sensing results will be presented where thermal energy is harvested by the AuNRs, which replaces the need for an external incident light source. Results from gas sensing experiments that utilize thermal energy harvesting are in good agreement with experiments which use an external incident light source. Principal component analysis results demonstrate that by selecting the most "active" wavelengths in a plasmonic band, the wavelength space can be reduced from hundreds of monitored wavelengths to just four, without loss of information about selectivity of the AuNRs. By combining thermal stability, the thermal energy harvesting capability, and the selectivity in gas detection (achieved through multivariate analysis), integration of plasmonic sensors into combustion environments can be greatly simplified.

  17. Phase change thermal storage for a solar total energy system

    NASA Technical Reports Server (NTRS)

    Rice, R. E.; Cohen, B. M.

    1978-01-01

    An analytical and experimental program is being conducted on a one-tenth scale model of a high-temperature (584 K) phase-change thermal energy storage system for installation in a solar total energy test facility at Albuquerque, New Mexico, U.S.A. The thermal storage medium is anhydrous sodium hydroxide with 8% sodium nitrate. The program will produce data on the dynamic response of the system to repeated cycles of charging and discharging simulating those of the test facility. Data will be correlated with a mathematical model which will then be used in the design of the full-scale system.

  18. Experimental Wave Tank Test for Reference Model 3 Floating-Point Absorber Wave Energy Converter Project

    SciTech Connect

    Yu, Y. H.; Lawson, M.; Li, Y.; Previsic, M.; Epler, J.; Lou, J.

    2015-01-01

    The U.S. Department of Energy established a reference model project to benchmark a set of marine and hydrokinetic technologies including current (tidal, open-ocean, and river) turbines and wave energy converters. The objectives of the project were to first evaluate the status of these technologies and their readiness for commercial applications. Second, to evaluate the potential cost of energy and identify cost-reduction pathways and areas where additional research could be best applied to accelerate technology development to market readiness.

  19. Revealing the Dusty Warm Absorber in MCG -6-30-15 with the Chandra High-Energy Transmission Grating

    NASA Astrophysics Data System (ADS)

    Lee, Julia C.; Ogle, Patrick M.; Canizares, Claude R.; Marshall, Herman L.; Schulz, Norbert S.; Morales, Raquel; Fabian, Andrew C.; Iwasawa, Kazushi

    2001-06-01

    We present detailed evidence for a warm absorber in the Seyfert 1 galaxy MCG -6-30-15 and dispute earlier claims for relativistic O line emission. The High-Energy Transmission Grating spectra show numerous narrow, unresolved (FWHM<~200 km s-1) absorption lines from a wide range of ionization states of N, O, Mg, Ne, Si, S, Ar, and Fe. The O VII edge and the 1s2-1snp resonance line series to n=9 are clearly detected at rest in the active galactic nucleus frame. We attribute previous reports of an apparently highly redshifted O VII edge to the 1s2-1snp (n>5) O VII resonance lines and a neutral Fe L absorption complex. The shape of the Fe L feature is nearly identical to that seen in the spectra of several X-ray binaries and in laboratory data. The implied dust column density agrees with that obtained from reddening studies and gives the first direct X-ray evidence for dust embedded in a warm absorber. The O VIII resonance lines and the weak edge are also detected, and the spectral rollover below ~2 keV is explained by the superposition of numerous absorption lines and edges. We identify, for the first time, a KLL resonance in the O VI photoabsorption cross section, giving a measure of the O VI column density. The O VII (f) emission detected at the systemic velocity implies a covering fraction of ~5% (depending on the observed vs. time-averaged ionizing flux). Our observations show that a dusty warm absorber model is not only adequate to explain all the spectral features >~0.48 keV (<~26 Å) but that the data require it. This contradicts the interpretation of Branduardi-Raymont and coworkers that this spectral region is dominated by highly relativistic line emission from the vicinity of the black hole.

  20. Modeling Thermal and Environmental Effects of Prototype Scale Ocean Thermal Energy Conversion

    NASA Astrophysics Data System (ADS)

    Hamrick, J. M.

    2010-12-01

    Ocean thermal energy conversion (OTEC) utilizes the temperature difference between the mix lay and deep water electricity generation. The small temperature difference compared to other thermal-electric generation devises, typically between 20 and 25 C, requires the substantial volumetric flows on the order of hundreds of cubic meters per second to generate net energy and recover capital investments. This presentation described the use of a high resolution three-dimensional EFDC model with an embedded jet-plume model to simulate the thermal and environmental impacts of a number of prototype OTEC configurations on the southwest coast of Oahu, Hawaii. The EFDC model is one-way nested into a larger scale ROMS model to allow for realistic incorporation of region processes including external and internal tides and sub-tidal circulation. Impacts on local thermal structure and the potential for nutrient enrichment of the mixed layer are addressed with model and presented.

  1. Solar Energy - An Option for Future Energy Production

    ERIC Educational Resources Information Center

    Glaser, Peter E.

    1972-01-01

    Discusses the exponential growth of energy consumption and future consequences. Possible methods of converting solar energy to power such as direct energy conversion, focusing collectors, selective rediation absorbers, ocean thermal gradient, and space solar power are considered. (DF)

  2. Thermal energy storage technical progress report, April 1990--March 1991

    SciTech Connect

    Tomlinson, J.J.

    1992-03-01

    The Department of Energy (DOE) is supporting development of thermal energy storage (TES) as a means of efficiently coupling energy supplies to variable heating or cooling demands. Uses of TES include electrical demand-side management in buildings and industry, extending the utilization of renewable energy resources such as solar, and recovery of waste heat from periodic industrial processes. Technical progress to develop TES for specific diurnal and industrial applications under Oak Ridge National Laboratory`s TES program from April 1990 to March 1992 is reported and covers research in the areas of low temperature sorption, direct contact ice making, latent heat storage plasterboard and latent/sensible heat regenerator technology development.

  3. Thermal energy storage technical progress report, April 1990--March 1991

    SciTech Connect

    Tomlinson, J.J.

    1992-03-01

    The Department of Energy (DOE) is supporting development of thermal energy storage (TES) as a means of efficiently coupling energy supplies to variable heating or cooling demands. Uses of TES include electrical demand-side management in buildings and industry, extending the utilization of renewable energy resources such as solar, and recovery of waste heat from periodic industrial processes. Technical progress to develop TES for specific diurnal and industrial applications under Oak Ridge National Laboratory's TES program from April 1990 to March 1992 is reported and covers research in the areas of low temperature sorption, direct contact ice making, latent heat storage plasterboard and latent/sensible heat regenerator technology development.

  4. Ocean Thermal Energy Conversion Program Management Plan

    SciTech Connect

    Combs, R E

    1980-01-01

    The Office of the Associate Laboratory Director for Energy and Environmental Technology has established the OTEC Program Management Office to be responsible for the ANL-assigned tasks of the OTEC Program under DOE's Chicago Operations and Regional Office (DOE/CORO). The ANL OTEC Program Management Plan is essentially a management-by-objective plan. The principal objective of the program is to provide lead technical support to CORO in its capacity as manager of the DOE power-system program. The Argonne OTEC Program is divided into three components: the first deals with development of heat exchangers and other components of OTEC power systems, the second with development of biofouling counter-measures and corrosion-resistant materials for these components in seawater service, and the third with environmental and climatic impacts of OTEC power-system operation. The essential points of the Management Plan are summarized, and the OTEC Program is described. The organization of the OTEC Program at ANL is described including the functions, responsibilities, and authorities of the organizational groupings. The system and policies necessary for the support and control functions within the organization are discussed. These functions cross organizational lines, in that they are common to all of the organization groups. Also included are requirements for internal and external reports.

  5. Advanced phase change composite by thermally annealed defect-free graphene for thermal energy storage.

    PubMed

    Xin, Guoqing; Sun, Hongtao; Scott, Spencer Michael; Yao, Tiankai; Lu, Fengyuan; Shao, Dali; Hu, Tao; Wang, Gongkai; Ran, Guang; Lian, Jie

    2014-09-10

    Organic phase change materials (PCMs) have been utilized as latent heat energy storage and release media for effective thermal management. A major challenge exists for organic PCMs in which their low thermal conductivity leads to a slow transient temperature response and reduced heat transfer efficiency. In this work, 2D thermally annealed defect-free graphene sheets (GSs) can be obtained upon high temperature annealing in removing defects and oxygen functional groups. As a result of greatly reduced phonon scattering centers for thermal transport, the incorporation of ultralight weight and defect free graphene applied as nanoscale additives into a phase change composite (PCC) drastically improve thermal conductivity and meanwhile minimize the reduction of heat of fusion. A high thermal conductivity of the defect-free graphene-PCC can be achieved up to 3.55 W/(m K) at a 10 wt % graphene loading. This represents an enhancement of over 600% as compared to pristine graphene-PCC without annealing at a comparable loading, and a 16-fold enhancement than the pure PCM (1-octadecanol). The defect-free graphene-PCC displays rapid temperature response and superior heat transfer capability as compared to the pristine graphene-PCC or pure PCM, enabling transformational thermal energy storage and management.

  6. Efficient thermal energy harvesting using nanoscale magnetoelectric heterostructures

    NASA Astrophysics Data System (ADS)

    Etesami, S. R.; Berakdar, J.

    2016-02-01

    Thermomechanical cycles with a ferroelectric working substance convert heat to electrical energy. As shown here, magnetoelectrically coupled ferroelectric/ferromagnetic composites (also called multiferroics) allow for an efficient thermal energy harvesting at room temperature by exploiting the pyroelectric effect. By virtue of the magnetoelectric coupling, external electric and magnetic fields can steer the operation of these heat engines. Our theoretical predictions are based on a combination of Landau-Khalatnikov-Tani approach (with a Ginzburg-Landau-Devonshire potential) to simulate the ferroelectric dynamics coupled to the magnetic dynamics. The latter is treated via the electric-polarization-dependent Landau-Lifshitz-Gilbert equation. By performing an adapted Olsen cycle we show that a multiferroic working substance is potentially much more superior to the sole ferroelectrics, as far as the thermal energy harvesting using pyroelectric effect is concerned. Our proposal holds promise not only for low-energy consuming devices but also for cooling technology.

  7. Research and development on ocean thermal energy conversion in Japan

    SciTech Connect

    Uehara, H.

    1982-08-01

    The study of Ocean Thermal Energy Conversion (OTEC) in Japan has been conducted under the leadership of a team of the ''Sunshine Project'', a national new energy development project promoted by the Ministry of International Trade and Industries (MITI) since 1974. At present, two experimental OTEC power plants -Nauru's OTEC plant and Imari's OTEC plant are operating. In this paper, the review of research and development activity of these two OTEC plants in Japan is made.

  8. High temperature latent heat thermal energy storage to augment solar thermal propulsion for microsatellites

    NASA Astrophysics Data System (ADS)

    Gilpin, Matthew R.

    Solar thermal propulsion (STP) offers an unique combination of thrust and efficiency, providing greater total DeltaV capability than chemical propulsion systems without the order of magnitude increase in total mission duration associated with electric propulsion. Despite an over 50 year development history, no STP spacecraft has flown to-date as both perceived and actual complexity have overshadowed the potential performance benefit in relation to conventional technologies. The trend in solar thermal research over the past two decades has been towards simplification and miniaturization to overcome this complexity barrier in an effort finally mount an in-flight test. A review of micro-propulsion technologies recently conducted by the Air Force Research Laboratory (AFRL) has identified solar thermal propulsion as a promising configuration for microsatellite missions requiring a substantial Delta V and recommended further study. A STP system provides performance which cannot be matched by conventional propulsion technologies in the context of the proposed microsatellite ''inspector" requiring rapid delivery of greater than 1500 m/s DeltaV. With this mission profile as the target, the development of an effective STP architecture goes beyond incremental improvements and enables a new class of microsatellite missions. Here, it is proposed that a bi-modal solar thermal propulsion system on a microsatellite platform can provide a greater than 50% increase in Delta V vs. chemical systems while maintaining delivery times measured in days. The realization of a microsatellite scale bi-modal STP system requires the integration of multiple new technologies, and with the exception of high performance thermal energy storage, the long history of STP development has provided "ready" solutions. For the target bi-modal STP microsatellite, sensible heat thermal energy storage is insufficient and the development of high temperature latent heat thermal energy storage is an enabling

  9. Regolith thermal energy storage for lunar nighttime power

    NASA Technical Reports Server (NTRS)

    Tillotson, Brian

    1992-01-01

    A scheme for providing nighttime electric power to a lunar base is described. This scheme stores thermal energy in a pile of regolith. Any such scheme must somehow improve on the poor thermal conductivity of lunar regolith in vacuum. Two previous schemes accomplish this by casting or melting the regolith. The scheme described here wraps the regolith in a gas-tight bag and introduces a light gas to enhance thermal conductivity. This allows the system to be assembled with less energy and equipment than schemes which require melting of regolith. A point design based on the new scheme is presented. Its mass from Earth compares favorably with the mass of a regenerative fuel cell of equal capacity.

  10. Dark energy in thermal equilibrium with the cosmological horizon?

    NASA Astrophysics Data System (ADS)

    Poitras, Vincent

    2014-03-01

    According to a generalization of black hole thermodynamics to a cosmological framework, it is possible to define a temperature for the cosmological horizon. The hypothesis of thermal equilibrium between the dark energy and the horizon has been considered by many authors. We find the restrictions imposed by this hypothesis on the energy transfer rate (Qi) between the cosmological fluids, assuming that the temperature of the horizon has the form T =b/2πR, where R is the radius of the horizon. We more specifically consider two types of dark energy: Chaplygin gas (CG) and dark energy with a constant equation of state parameter (wDE). In each case, we show that for a given radius R, there is a unique term Qde that is consistent with thermal equilibrium. We also consider the situation where, in addition to dark energy, other fluids (cold matter, radiation) are in thermal equilibrium with the horizon. We find that the interaction terms required for this will generally violate energy conservation (∑iQi=0).

  11. Robust energy-absorbing compensators for the ACTEX II test article

    NASA Astrophysics Data System (ADS)

    Blaurock, Carl A.; Miller, David W.; Nye, Ted

    1995-05-01

    The paper addresses the problem of satellite solar panel vibration. A multi-layer vibration control scheme is investigated using a flight test article. Key issues in the active control portion are presented in the paper. The paper discusses the primary control design drivers, which are the time variations in modal frequencies due to configuration and thermal changes. A local control design approach is investigated, but found to be unworkable due to sensor/actuator non-collocation. An alternate design process uses linear robust control techniques, by describing the modal shifts as uncertainties. Multiple modal design, alpha- shifted multiple model, and a feedthrough compensation scheme are examined. Ground and simulation tests demonstrate that the resulting controllers provide significant vibration reduction in the presence of expected system variations.

  12. Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.

    ERIC Educational Resources Information Center

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

  13. Thermal energy storage. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-09-01

    The cited reports of federally-funded research concern thermal energy storage. The citations cover the design of equipment, performance evaluation, theory, materials used, and experimental design. This updated bibliography contains 240 citations, 128 of which are new entries to the previous edition.

  14. CALORSTOCK 1994: Thermal energy storage. Better economy, environment, technology

    NASA Astrophysics Data System (ADS)

    Kangas, M. T.; Lund, P. D.

    This publication is the second volume of the Proceedings of CALORSTOCK'94, the Sixth International Conference on Thermal Energy Storage held in Espoo, Finland on 22-25 Aug. 1994. This volume contains 51 presentations from the following six sessions: Chemical storage; Heat storage and environment; Central solar heating plants with seasonal storage; Water storage pits and tanks; Cooling; and National activities.

  15. Fuels and chemicals from biomass using solar thermal energy

    NASA Technical Reports Server (NTRS)

    Giori, G.; Leitheiser, R.; Wayman, M.

    1981-01-01

    The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry.

  16. Quantitative evaluation of ocean thermal energy conversion (OTEC): executive briefing

    SciTech Connect

    Gritton, E.C.; Pei, R.Y.; Hess, R.W.

    1980-08-01

    Documentation is provided of a briefing summarizing the results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications. The study concentrated on a central station power plant located in the Gulf of Mexico and delivering power to the mainland United States. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

  17. Fuels and chemicals from biomass using solar thermal energy

    NASA Astrophysics Data System (ADS)

    Giori, G.; Leitheiser, R.; Wayman, M.

    1981-05-01

    The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry.

  18. Thermal energy storage subsystems. A collection of quarterly reports

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The design, development, and progress toward the delivery of three subsystems is discussed. The subsystem used a salt hydrate mixture for thermal energy storage. The program schedules, technical data, and other program activities from October 1, 1976, through December 31, 1977 are presented.

  19. Quantitation of absorbed or deposited materials on a substrate that measures energy deposition

    DOEpatents

    Grant, Patrick G.; Bakajin, Olgica; Vogel, John S.; Bench, Graham

    2005-01-18

    This invention provides a system and method for measuring an energy differential that correlates to quantitative measurement of an amount mass of an applied localized material. Such a system and method remains compatible with other methods of analysis, such as, for example, quantitating the elemental or isotopic content, identifying the material, or using the material in biochemical analysis.

  20. Thermal damage suppression of a black phosphorus saturable absorber for high-power operation of pulsed fiber lasers

    NASA Astrophysics Data System (ADS)

    Lee, Donghyun; Park, Kichul; Debnath, Pulak C.; Kim, Inho; Song, Yong-Won

    2016-09-01

    Recent studies of black phosphorus (BP) have shown its future potential in the field of photonics. We determined the optical damage threshold of BP at 21.8 dBm in a fiber ring laser cavity, and demonstrated the high-power operation capacity of an evanescent field interaction-based BP saturable absorber. The long-term stability of a passively mode-locked fiber laser with a saturable absorber operating at the optical power of 23.3 dBm was verified for 168 h without any significant performance degradation. The center wavelength, spectral width, and pulse width of the laser output are 1558.8 nm, 14.2 nm, and 805 fs, respectively.

  1. Thermal damage suppression of a black phosphorus saturable absorber for high-power operation of pulsed fiber lasers.

    PubMed

    Lee, Donghyun; Park, Kichul; Debnath, Pulak C; Kim, Inho; Song, Yong-Won

    2016-09-09

    Recent studies of black phosphorus (BP) have shown its future potential in the field of photonics. We determined the optical damage threshold of BP at 21.8 dBm in a fiber ring laser cavity, and demonstrated the high-power operation capacity of an evanescent field interaction-based BP saturable absorber. The long-term stability of a passively mode-locked fiber laser with a saturable absorber operating at the optical power of 23.3 dBm was verified for 168 h without any significant performance degradation. The center wavelength, spectral width, and pulse width of the laser output are 1558.8 nm, 14.2 nm, and 805 fs, respectively.

  2. Enhancing low-grade thermal energy recovery in a thermally regenerative ammonia battery using elevated temperatures.

    PubMed

    Zhang, Fang; LaBarge, Nicole; Yang, Wulin; Liu, Jia; Logan, Bruce E

    2015-03-01

    A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72 °C produced a power density of 236 ± 8 Wm(-2), with a linear decrease in power to 95 ± 5 Wm(-2) at 23 °C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Wh m(-3) at a discharge energy efficiency of 54% and a temperature of 37 °C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.

  3. Spider orb webs rely on radial threads to absorb prey kinetic energy.

    PubMed

    Sensenig, Andrew T; Lorentz, Kimberly A; Kelly, Sean P; Blackledge, Todd A

    2012-08-07

    The kinetic energy of flying insect prey is a formidable challenge for orb-weaving spiders. These spiders construct two-dimensional, round webs from a combination of stiff, strong radial silk and highly elastic, glue-coated capture spirals. Orb webs must first stop the flight of insect prey and then retain those insects long enough to be subdued by the spiders. Consequently, spider silks rank among the toughest known biomaterials. The large number of silk threads composing a web suggests that aerodynamic dissipation may also play an important role in stopping prey. Here, we quantify energy dissipation in orb webs spun by diverse species of spiders using data derived from high-speed videos of web deformation under prey impact. By integrating video data with material testing of silks, we compare the relative contributions of radial silk, the capture spiral and aerodynamic dissipation. Radial silk dominated energy absorption in all webs, with the potential to account for approximately 100 per cent of the work of stopping prey in larger webs. The most generous estimates for the roles of capture spirals and aerodynamic dissipation show that they rarely contribute more than 30 per cent and 10 per cent of the total work of stopping prey, respectively, and then only for smaller orb webs. The reliance of spider orb webs upon internal energy absorption by radial threads for prey capture suggests that the material properties of the capture spirals are largely unconstrained by the selective pressures of stopping prey and can instead evolve freely in response to alternative functional constraints such as adhering to prey.

  4. Thermal energy storage - overview and specific insight into nitrate salts for sensible and latent heat storage.

    PubMed

    Pfleger, Nicole; Bauer, Thomas; Martin, Claudia; Eck, Markus; Wörner, Antje

    2015-01-01

    Thermal energy storage (TES) is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition processes as well as a new method to develop optimized salt systems.

  5. Flexible hybrid energy cell for simultaneously harvesting thermal, mechanical, and solar energies.

    PubMed

    Yang, Ya; Zhang, Hulin; Zhu, Guang; Lee, Sangmin; Lin, Zong-Hong; Wang, Zhong Lin

    2013-01-22

    We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs).

  6. High-temperature molten salt thermal energy storage systems

    NASA Technical Reports Server (NTRS)

    Petri, R. J.; Claar, T. D.; Tison, R. R.; Marianowski, L. G.

    1980-01-01

    The results of comparative screening studies of candidate molten carbonate salts as phase change materials (PCM) for advanced solar thermal energy storage applications at 540 to 870 C (1004 to 1600 F) and steam Rankine electric generation at 400 to 540 C (752 to 1004 F) are presented. Alkali carbonates are attractive as latent heat storage materials because of their relatively high storage capacity and thermal conductivity, low corrosivity, moderate cost, and safe and simple handling requirements. Salts were tested in 0.1 kWhr lab scale modules and evaluated on the basis of discharge heat flux, solidification temperature range, thermal cycling stability, and compatibility with containment materials. The feasibility of using a distributed network of high conductivity material to increase the heat flux through the layer of solidified salt was evaluated. The thermal performance of an 8 kWhr thermal energy storage (TES) module containing LiKCO3 remained very stable throughout 5650 hours and 130 charge/discharge cycles at 480 to 535 C (896 to 995 F). A TES utilization concept of an electrical generation peaking subsystem composed of a multistage condensing steam turbine and a TES subsystem with a separate power conversion loop was defined. Conceptual designs for a 100 MW sub e TES peaking system providing steam at 316 C, 427 C, and 454 C (600 F, 800 F, and 850 F) at 3.79 million Pa (550 psia) were developed and evaluated. Areas requiring further investigation have also been identified.

  7. Information-to-free-energy conversion: Utilizing thermal fluctuations

    PubMed Central

    Toyabe, Shoichi; Muneyuki, Eiro

    2013-01-01

    Maxwell’s demon is a hypothetical creature that can convert information to free energy. A debate that has lasted for more than 100 years has revealed that the demon’s operation does not contradict the laws of thermodynamics; hence, the demon can be realized physically. We briefly review the first experimental demonstration of Maxwell’s demon of Szilard’s engine type that converts information to free energy. We pump heat from an isothermal environment by using the information about the thermal fluctuations of a Brownian particle and increase the particle’s free energy. PMID:27493548

  8. Simulating the Response of a Composite Honeycomb Energy Absorber. Part 1; Dynamic Crushing of Components and Multi-Terrain Impacts

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.; Polanco, Michael A.

    2012-01-01

    This paper describes the experimental and analytical evaluation of an externally deployable composite honeycomb structure that is designed to attenuate impact energy during helicopter crashes. The concept, designated the Deployable Energy Absorber (DEA), utilizes an expandable Kevlar (Registered Trademark) honeycomb to dissipate kinetic energy through crushing. The DEA incorporates a unique flexible hinge design that allows the honeycomb to be packaged and stowed until needed for deployment. Experimental evaluation of the DEA included dynamic crush tests of multi-cell components and vertical drop tests of a composite fuselage section, retrofitted with DEA blocks, onto multi-terrain. Finite element models of the test articles were developed and simulations were performed using the transient dynamic code, LSDYNA (Registered Trademark). In each simulation, the DEA was represented using shell elements assigned two different material properties: Mat 24, an isotropic piecewise linear plasticity model, and Mat 58, a continuum damage mechanics model used to represent laminated composite fabrics. DEA model development and test-analysis comparisons are presented.

  9. Wedge Absorbers for Final Cooling for a High-Energy High-Luminosity Lepton Collider

    SciTech Connect

    Neuffer, David; Mohayai, Tanaz; Snopok, Pavel; Summers, Don

    2016-06-01

    A high-energy high-luminosity muon collider scenario requires a "final cooling" system that reduces transverse emittance to ~25 microns (normalized) while allowing longitudinal emittance increase. Ionization cooling using high-field solenoids (or Li Lens) can reduce transverse emittances to ~100 microns in readily achievable configurations, confirmed by simulation. Passing these muon beams at ~100 MeV/c through cm-sized diamond wedges can reduce transverse emittances to ~25 microns, while increasing longitudinal emittance by a factor of ~5. Implementation will require optical matching of the exiting beam into downstream acceleration systems.

  10. Experimental investigation of a packed bed thermal energy storage system

    NASA Astrophysics Data System (ADS)

    Cascetta, Mario; Cau, Giorgio; Puddu, Pierpaolo; Serra, Fabio

    2015-11-01

    In this work experimental investigations on a thermal energy storage system with a solid material as storage media and air as heat transfer fluid will be presented. The experimental test rig, installed at the DIMCM of the University of Cagliari, consists of a carbon steel tank filled with freely poured alumina beads that allows investigations of heat transfer phenomena in packed beds. The aim of this work is to show the influence of the operating conditions and physical parameters on thermocline formation and, in particular, the thermal behaviour of the thermal energy storage for repeated charging and discharging cycles. Better charging efficiency is obtained for lower values of mass flow rate and maximum air temperature and for increasing aspect ratio. A decreasing influence of the metal wall with continuous operation is also highlighted. In conclusion, the analysis focuses on the thermal hysteresis phenomenon, which causes degradation of the thermocline and the reduction of the energy that can be stored by the accumulator as the repeated number of cycles increases.

  11. Nanoparticles for heat transfer and thermal energy storage

    DOEpatents

    Singh, Dileep; Cingarapu, Sreeram; Timofeeva, Elena V.; Moravek, Michael

    2015-07-14

    An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

  12. Dimensional Analysis of Ocean Thermal Energy Conversion Heat Exchangers

    DTIC Science & Technology

    1977-06-30

    8217thIJt4IiTY CLASSIFICATION OF TWI4S PAG(E ona Dola t ern.r) 20. (continued) c-a• of factors having significance in OTEC (Ocean Thermal Energy Conversion...heat exchangers. Certain of these groups are then evaluated for a model and prototype OTEC -Type heat exchanger using the same working fluid and ex...Development Administration, and the U. S. Navy are brought out. Chapter II investigates the scaling problems of heat ex- changers in OTEC (Ocean Thermal

  13. Composite salt/ceramic media for thermal energy storage applications

    NASA Astrophysics Data System (ADS)

    Claar, T. D.; Petri, R. J.; Ong, E. T.

    An advanced thermal energy storage (TES) media concept based on composite carbonate salt/ceramic materials is being developed for high-temperature applications such as industrial waste heat recovery and storage and solar thermal power systems. This composite latent/sensible media concept permits direct-contact heat exchange between the storage media and compatible working fluids, thus offering significant potential TES system performance and cost advantages over previous molten-salt latent-heat storage systems. Composite media development activities, materials stability test results, and planned TES performance evaluation tests are discussed.

  14. Simulation and evaluation of latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Sigmon, T. W.

    1980-01-01

    The relative value of thermal energy storage (TES) for heat pump storage (heating and cooling) as a function of storage temperature, mode of storage (hotside or coldside), geographic locations, and utility time of use rate structures were derived. Computer models used to simulate the performance of a number of TES/heat pump configurations are described. The models are based on existing performance data of heat pump components, available building thermal load computational procedures, and generalized TES subsystem design. Life cycle costs computed for each site, configuration, and rate structure are discussed.

  15. Modeling Pumped Thermal Energy Storage with Waste Heat Harvesting

    NASA Astrophysics Data System (ADS)

    Abarr, Miles L. Lindsey

    This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual-functionality. This dissertation first presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was +/- 0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed <1% error for bottoming mode heat transfer. The system model was used to conduct sensitivity analysis, baseline performance, and levelized cost of energy of a recently proposed Pumped Thermal Energy Storage and Bottoming System (Bot-PTES) that uses ammonia as the working fluid. This analysis focused on the effects of hot thermal storage utilization, system pressure, and evaporator/condenser size on the system performance. This work presents the estimated performance for a proposed baseline Bot-PTES. Results of this analysis showed that all selected parameters had significant effects on efficiency, with the evaporator/condenser size having the largest effect over the selected ranges. Results for the baseline case showed stand-alone energy storage efficiencies between 51 and 66% for varying power levels and charge states, and a stand-alone bottoming efficiency of 24%. The resulting efficiencies for this case were low compared to competing technologies; however, the dual-functionality of the Bot-PTES enables it to have higher capacity factor, leading to 91-197/MWh levelized cost

  16. The Development of Two Composite Energy Absorbers for Use in a Transport Rotorcraft Airframe Crash Testbed (TRACT 2) Full-Scale Crash Test

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Jackson, Karen E.; Annett, Martin S.; Seal, Michael D.; Fasanella, Edwin L.

    2015-01-01

    Two composite energy absorbers were developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program. A conical-shaped energy absorber, designated the conusoid, was evaluated that consisted of four layers of hybrid carbon-Kevlar plain weave fabric oriented at [+45deg/-45deg/-45deg/+45deg] with respect to the vertical direction. A sinusoidal-shaped energy absorber, designated the sinusoid, was developed that consisted of hybrid carbon-Kevlar plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical direction, and a closed-cell ELFOAM P200 polyisocyanurate (2.0-lb/cu ft) foam core. The design goal for the energy absorbers was to achieve average floor-level accelerations of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in both designs were assessed through dynamic crush testing of component specimens. Once the designs were finalized, subfloor beams of each configuration were fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorbers prior to retrofit into TRACT 2. The retrofitted airframe was crash tested under combined forward and vertical velocity conditions onto soft soil. Finite element models were developed of all test articles and simulations were performed using LS-DYNA, a commercial nonlinear explicit transient dynamic finite element code. Test-analysis results are presented for each energy absorber as comparisons of time-history responses, as well as predicted and experimental structural deformations and progressive damage under impact loading for each evaluation level.

  17. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Efficient and Robust Design for Absorbing Boundary Conditions in Atomistic Computations

    NASA Astrophysics Data System (ADS)

    Fang, Ming; Tang, Shao-Qiang

    2009-11-01

    We propose an efficient and robust way to design absorbing boundary conditions in atomistic computations. An optimal discrete boundary condition is obtained by minimizing a functional of a reflection coefficient integral over a range of wave numbers. The minimization is performed with respect to a set of wave numbers, at which transparent absorption is reached. Compared with the optimization with respect to the boundary condition coefficients suggested by E and Huang [Phys. Rev. Lett. 87 (2001) 133501], we reduce considerably the number of independent variables and the computing cost. We further demonstrate with numerical examples that both the optimization and the wave absorption are more robust in the proposed design.

  18. Reconstructing the energy band electronic structure of pulsed laser deposited CZTS thin films intended for solar cell absorber applications

    NASA Astrophysics Data System (ADS)

    Pandiyan, Rajesh; Oulad Elhmaidi, Zakaria; Sekkat, Zouheir; Abd-lefdil, Mohammed; El Khakani, My Ali

    2017-02-01

    We report here on the use of pulsed KrF-laser deposition (PLD) technique for the growth of high-quality Cu2ZnSnS4 (CZTS) thin films onto Si, and glass substrates without resorting to any post sulfurization process. The PLD-CZTS films were deposited at room temperature (RT) and then subjected to post annealing at different temperatures ranging from 200 to 500 °C in Argon atmosphere. The X-ray diffraction and Raman spectroscopy confirmed that the PLD films crystallize in the characteristic kesterite CZTS structure regardless of their annealing temperature (Ta), but their crystallinity is much improved for Ta ≥ 400 °C. The PLD-CZTS films were found to exhibit a relatively dense morphology with a surface roughness (RMS) that increases with Ta (from ∼14 nm at RT to 70 nm at Ta = 500 °C with a value around 40 nm for Ta = 300-400 °C). The optical bandgap of the PLD-CZTS films, was derived from UV-vis transmission spectra analysis, and found to decrease from 1.73 eV for non-annealed films to ∼1.58 eV for those annealed at Ta = 300 °C. These band gap values are very close to the optimum value needed for an ideal solar cell absorber. In order to achieve a complete reconstruction of the one-dimensional energy band structure of these PLD-CZTS absorbers, we have combined both XPS and UPS spectroscopies to determine their chemical bondings, the position of their valence band maximum (relative to Fermi level), and their work function values. This enabled us to sketch out, as accurately as possible, the band alignment of the heterojunction interface formed between CZTS and both CdS and ZnS buffer layer materials.

  19. A fibre optic scintillator dosemeter for absorbed dose measurements of low-energy X-ray-emitting brachytherapy sources.

    PubMed

    Sliski, Alan; Soares, Christopher; Mitch, Michael G

    2006-01-01

    A newly developed dosemeter using a 0.5 mm diameter x 0.5 mm thick cylindrical plastic scintillator coupled to the end of a fibre optic cable is capable of measuring the absorbed dose rate in water around low-activity, low-energy X-ray emitters typically used in prostate brachytherapy. Recent tests of this dosemeter showed that it is possible to measure the dose rate as a function of distance in water from 2 to 30 mm of a (103)Pd source of air-kerma strength 3.4 U (1 U = 1 microGy m(2) h(-1)), or 97 MBq (2.6 mCi) apparent activity, with good signal-to-noise ratio. The signal-to-noise ratio is only dependent on the integration time and background subtraction. The detector volume is enclosed in optically opaque, nearly water-equivalent materials so that there is no polar response other than that due to the shape of the scintillator volume chosen, in this case cylindrical. The absorbed dose rate very close to commercial brachytherapy sources can be mapped in an automated water phantom, providing a 3-D dose distribution with sub-millimeter spatial resolution. The sensitive volume of the detector is 0.5 mm from the end of the optically opaque waterproof housing, enabling measurements at very close distances to sources. The sensitive detector electronics allow the measurement of very low dose rates, as exist at centimeter distances from these sources. The detector is also applicable to mapping dose distributions from more complex source geometries such as eye applicators for treating macular degeneration.

  20. Monte Carlo MCNP-4B energy absorbed fractions in Head and Brain calculated in "The ORNL mathematical phantom series" and in "MIRD 15" mathematical phantoms

    NASA Astrophysics Data System (ADS)

    Valle, Saúl H.; Lorenzo, Daniel M.; Gual, Maritza R.

    2002-08-01

    Due to the use of many new radiopharmaceuticals in Brain imaging there exists the need of predicting absorbed energy and doses during the irradiation process within the head specificity in brain. In order to evaluate the MCNP-4b capability of calculating absorbed energy in Brain and Head we calculated it first using the geometrical data from "The ORNL mathematical phantom series" and subsequently a more anthropomorphic model "current MIRD 15". The results are compared with validated data and the conclusions are shown at the end.

  1. Higher-order-mode absorbers for energy recovery linac cryomodules at Brookhaven National Laboratory

    SciTech Connect

    Hahn, H.; Ben-Zvi, I.; Calaga, R,; Hammons, L.; Johnson, E.C.; Kewisch, J.; Litvinenko, V.N.; Xu, W.

    2010-12-03

    Several future accelerator projects at Brookhaven for the Relativistic Heavy Ion Collider (RHIC) are based on energy recovery linacs (ERLs) with high-charge high-current electron beams. Their stable operation mandates effective higher-order-mode (HOM) damping. The development of HOM dampers for these projects is pursued actively at this laboratory. Strong HOM damping was experimentally demonstrated both at room and at superconducting (SC) temperatures in a prototype research and development (R&D) five-cell niobium superconducting rf (SRF) cavity with ferrite dampers. Two room-temperature mock-up five-cell copper cavities were used to study various damper configurations with emphasis on capacitive antenna dampers. An innovative type of ferrite damper over a ceramic break for an R&D SRF electron gun also was developed. For future SRF linacs longer cryomodules comprised of multiple superconducting cavities with reasonably short intercavity transitions are planned. In such a configuration, the dampers, located closer to the cavities, will be at cryogenic temperatures; this will impose additional constraints and complications. This paper presents the results of simulations and measurements of several damper configurations.

  2. Molten Glass for Thermal Storage: Advanced Molten Glass for Heat Transfer and Thermal Energy Storage

    SciTech Connect

    2012-01-01

    HEATS Project: Halotechnics is developing a high-temperature thermal energy storage system using a new thermal-storage and heat-transfer material: earth-abundant and low-melting-point molten glass. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Halotechnics new thermal storage material targets a price that is potentially cheaper than the molten salt used in most commercial solar thermal storage systems today. It is also extremely stable at temperatures up to 1200°C—hundreds of degrees hotter than the highest temperature molten salt can handle. Being able to function at high temperatures will significantly increase the efficiency of turning heat into electricity. Halotechnics is developing a scalable system to pump, heat, store, and discharge the molten glass. The company is leveraging technology used in the modern glass industry, which has decades of experience handling molten glass.

  3. Review of pyroelectric thermal energy harvesting and new MEMs based resonant energy conversion techniques

    SciTech Connect

    Hunter, Scott Robert; Lavrik, Nickolay V; Mostafa, Salwa; Rajic, Slobodan; Datskos, Panos G

    2012-01-01

    Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal

  4. Performance issues in solar thermal energy transport systems

    NASA Astrophysics Data System (ADS)

    Zimmerman, P. W.

    1986-07-01

    Pacific Northwest Laboratory, sponsored by the US Department of Energy through Sandia National Laboratories, is performing an assessment of three solar thermal electricity generating concepts; central receivers, dishes, and troughs. Concepts are being studied over a range of system sizes 0.5 MWe to 100 MWe with solar multiples from 1.0 to 2.8. Central receiver systems using molten salt, sodium, and water-steam working fluids are studied. The dish system selected for study uses a kinematic Stirling engine at the focal point, and the trough system is based on Accurex designed collectors heating a heat transfer oil. Of the three concepts studied, the central receiver and trough systems utilize thermal transport systems. A thermal transport system is the piping and fluid required to transfer thermal energy between receiver, and storage and between storage and steam generator. The literature contains many transport system designs, most of which are optimized with regard to cost and performance. We used the parameters specified from the optimizations to design our systems and scale the designs over the 0.5 MWe to 100 MWe size range. From these designs, thermal losses and pump sizes are derived then combined in a system model to obtain total annual averaged efficiency as a function of plant field size. We found that central receiver transport efficiency improves with field size whereas trough transport efficiency degrades with field size. We found that overnight cooldown accounts for roughly 50% of the total thermal losses for all transport systems. Trough performance is substantially degraded because the receiver tubes are not drained which allows a large overnight heat loss. Trough transport performance was found to be sensitive to fluid velocity.

  5. High Energy Density Thermal Batteries: Thermoelectric Reactors for Efficient Automotive Thermal Storage

    SciTech Connect

    2011-11-15

    HEATS Project: Sheetak is developing a new HVAC system to store the energy required for heating and cooling in EVs. This system will replace the traditional refrigerant-based vapor compressors and inefficient heaters used in today’s EVs with efficient, light, and rechargeable hot-and-cold thermal batteries. The high energy density thermal battery—which does not use any hazardous substances—can be recharged by an integrated solid-state thermoelectric energy converter while the vehicle is parked and its electrical battery is being charged. Sheetak’s converters can also run on the electric battery if needed and provide the required cooling and heating to the passengers—eliminating the space constraint and reducing the weight of EVs that use more traditional compressors and heaters.

  6. Comparison of the NMIJ and the ARPANSA standards for absorbed dose to water in high-energy photon beams.

    PubMed

    Shimizu, M; Morishita, Y; Kato, M; Tanaka, T; Kurosawa, T; Takata, N; Saito, N; Ramanathan, G; Harty, P D; Oliver, C; Wright, T; Butler, D J

    2015-04-01

    The authors report the results of an indirect comparison of the standards of absorbed dose to water in high-energy photon beams from a clinical linac and (60)Co radiation beam performed between the National Metrology Institute of Japan (NMIJ) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Three ionisation chambers were calibrated by the NMIJ in April and June 2013 and by the ARPANSA in May 2013. The average ratios of the calibration coefficients for the three ionisation chambers obtained by the NMIJ to those obtained by the ARPANSA were 0.9994, 1.0040 and 1.0045 for 6-, 10- and 15-MV (18 MV at the ARPANSA) high-energy photon beams, respectively. The relative standard uncertainty of the value was 7.2 × 10(-3). The ratio for (60)Co radiation was 0.9986(66), which is consistent with the results published in the key comparison of BIPM.RI(I)-K4.

  7. Absorbed dose measurements in dual energy X-ray absorptiometry (DXA).

    PubMed

    Bezakova, E; Collins, P J; Beddoe, A H

    1997-02-01

    In this study a predominantly film dosimetric method was used to measure the effective dose from posteroanterior (PA) lumbar spine and proximal femur scans performed on a Lunar DPX-L machine. Because of the very low dose rate in scanning mode, the depth dose data were determined using a stationary detector configuration. The characteristic curve for the film (Kodak TMAT-H) was obtained and depth dose measurements were made using slabs of "solid water". The film was calibrated using a superficial X-ray unit (calibrated against a standard traceable to a national standard). To assess the change in film response with beam hardening at depth, the film was exposed to calibration beams of different half value layer (HVL). The HVL of the DXA beam was determined for surface and depth doses using aluminium filters and a diamond detector (an energy independent device). All measurements were performed three times. Beam size was measured using film, and the scan areas and times were determined by scanning phantoms. The dose from a scan was calculated using Dsc = DTscAb/Asc, where D = dose rate (stationary), Tsc = scan time, Ab = beam area, and Asc = scan area. Organ doses were determined using an anatomical atlas and ICRP 23 female reference. All film measurements had good precision (coefficient of variation < 4%). There was little variation in film sensitivity with change in HVL (< 1% change for the first three HVLs) and consequently no corrections were applied to the depth dose data. Skin entrance dose was 11.5 microGy. Effective dose in females was 0.19 microSv for the PA lumbar spine. For the proximal femur scan, the effective dose was 0.14 microSv (ovaries included) and 0.023 microSv (ovaries excluded) for pre-menopausal and pos-menopausal women, respectively.

  8. High temperature thermal energy storage in steel and sand

    NASA Technical Reports Server (NTRS)

    Turner, R. H.

    1979-01-01

    The technical and economic potential for high temperature (343 C, 650 F) thermal energy storage in hollow steel ingots, pipes embedded in concrete, and for pipes buried in sand was evaluated. Because it was determined that concrete would separate from pipes due to thermal stresses, concrete was replaced by sand, which is free from thermal stresses. Variations of the steel ingot concept were not cost effective compared to the sand-pipe approach, therefore, the sand-pipe thermal storage unit (TSU) was evaluated in depth to assess the approximate tube spacing requirements consistent with different system performance characteristics and also attendant system costs. For large TSUs which do not require fast response times, the sand-pipe approach offers attractive possibilities. A pipe diameter about 9 cm (3.5 in) and pipe spacing of approximately 25 cm (10 in), with sand filling the interspaces, appears appropriate. Such a TSU system designed for 8 hours charge/discharge cycle has an energy unit storage cost (CE) of $2.63/kWhr-t and a power unit storage cost (Cp) of $42/kW-t (in 1977 dollars).

  9. An assessment methodology for thermal energy storage evaluation

    NASA Astrophysics Data System (ADS)

    Brown, D. R.; Dirks, J. A.; Drost, M. K.; Spanner, G. E.; Williams, T. A.

    1987-11-01

    This report documents an assessment methodology for evaluating the cost, performance, and overall economic feasibility of thermal energy storage (TES) concepts. The methodology was developed by Thermal Energy Storage Evaluation Program personnel at Pacific Northwest Laboratory (PNL) for use by PNL and other TES concept evaluators. The methodology is generically applicable to all TES concepts; however, specific analyses may require additional or more detailed definition of the ground rules, assumptions, and analytical approach. The overall objective of the assessment methodology is to assist in preparing equitable and proper evaluations of TES concepts that will allow developers and end-users to make valid decisions about research and development (R and D) and implementation. The methodology meets this objective by establishing standard approaches, ground rules, assumptions, and definitions that are analytically correct and can be consistently applied by concept evaluators.

  10. Designing energy dissipation properties via thermal spray coatings

    SciTech Connect

    Brake, Matthew R. W.; Hall, Aaron Christopher; Madison, Jonathan D.

    2016-12-14

    The coefficient of restitution is a measure of energy dissipation in a system across impact events. Often, the dissipative qualities of a pair of impacting components are neglected during the design phase. This research looks at the effect of applying a thin layer of metallic coating, using thermal spray technologies, to significantly alter the dissipative properties of a system. We studied the dissipative properties across multiple impacts in order to assess the effects of work hardening, the change in microstructure, and the change in surface topography. The results of the experiments indicate that any work hardening-like effects are likely attributable to the crushing of asperities, and the permanent changes in the dissipative properties of the system, as measured by the coefficient of restitution, are attributable to the microstructure formed by the thermal spray coating. Furthermore, the microstructure appears to be robust across impact events of moderate energy levels, exhibiting negligible changes across multiple impact events.

  11. An assessment methodology for thermal energy storage evaluation

    SciTech Connect

    Brown, D.R.; Dirks, J.A.; Drost, M.K.; Spanner, G.E.; Williams, T.A.

    1987-11-01

    This report documents an assessment methodology for evaluating the cost, performance, and overall economic feasibility of thermal energy storage (TES) concepts. The methodology was developed by Thermal Energy Storage Evaluation Program personnel at Pacific Northwest Laboratory (PNL) for use by PNL and other TES concept evaluators. The methodology is generically applicable to all TES concepts; however, specific analyses may require additional or more detailed definition of the ground rules, assumptions, and analytical approach. The overall objective of the assessment methodology is to assist in preparing equitable and proper evaluations of TES concepts that will allow developers and end-users to make valid decisions about research and development (R and D) and implementation. The methodology meets this objective by establishing standard approaches, ground rules, assumptions, and definitions that are analytically correct and can be consistently applied by concept evaluators. 15 refs., 4 figs., 13 tabs.

  12. Thermal modeling with solid/liquid phase change of the thermal energy storage experiment

    NASA Technical Reports Server (NTRS)

    Skarda, J. Raymond Lee

    1991-01-01

    A thermal model which simulates combined conduction and phase change characteristics of thermal energy storage (TES) materials is presented. Both the model and results are presented for the purpose of benchmarking the conduction and phase change capabilities of recently developed and unvalidated microgravity TES computer programs. Specifically, operation of TES-1 is simulated. A two-dimensional SINDA85 model of the TES experiment in cylindrical coordinates was constructed. The phase change model accounts for latent heat stored in, or released from, a node undergoing melting and freezing.

  13. Thermal Energy in Carbon Nanotube and Graphene Composite Materials

    NASA Astrophysics Data System (ADS)

    Schiffres, Scott N.

    Low-dimensional materials, like carbon nanotubes (CNTs) and graphene, possess extraordinary properties---higher thermal conductivity than any bulk material, mechanical strength 10-100 times greater than steel on a mass basis, and electrical current capacity 1000 times greater than copper. While composites incorporating these low-dimensional materials promise solutions to global sustainability challenges, significant transport barriers exist at the matrix interface that influence the composite properties. My PhD research sought to address this knowledge gap. I've experimentally explored how CNTs and graphene impact thermal conductivity when added in small volume fractions to gases, liquids and solids through the study of CNT aerogels (ultra lightweight, 8 kg/m3, 99.6% void space), and phase change nanocomposites (hexadecane-graphene). I measured the thermal conductivity of the CNT aerogel with various filling gases versus pressure using a novel technique that targeted ultralow thermal conductivity materials, called metal-coated 3o. I observed amplified energy transport length scales resulting from low gas accommodation, which is a general feature of carbon based nanoporous materials. Our evidence also shows that despite the high thermal conductivity of CNTs, thermal conduction through the CNT network is limited by the high thermal boundary resistance at van der Waals bonded CNT junctions. In the second system, I studied thermal and electrical conductivity of hexadecane- multi-layered-graphene (MLG) phase change nanocomposites to understand how morphology of the MLG network impacts transport. By adjusting the freezing rate, the electrical conductivity in the solid phase can be tuned between 1 and 5 orders-of-magnitude and the solid-liquid thermal conductivity ratio can be varied between 2.6 to 3.0. This research has yielded interesting insights into the tunability of nanocomposites and the physics underlying it, including evidence to indicate that the presence of

  14. Internal absorber solar collector

    DOEpatents

    Sletten, Carlyle J.; Herskovitz, Sheldon B.; Holt, F. S.; Sletten, E. J.

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

  15. Data Analysis for Ocean Thermal Energy Conversion (otec)

    DTIC Science & Technology

    1979-11-01

    Unit Number 01. The author wishes to thank Mr. David Boswell of DTNSRDC, Annapolis, Maryland for his work on OTEC software development. The...assistance of Mr. Glenn Grannemann of Carnegie-Mellon University, Pittsburgh, Pennsylvania, in reviewing Panama City OTEC data analysis techniques is...FOR OCEAN THERMAL ENERGY Technical Memodnndum CONVERSION ( OTEC ) , * IERFORMING Ono, XCIPOOT mulesea 7. AUTNORf.) .. CONTRACT OR GRANT S411jbdb .ftf

  16. Dish concentrators for solar thermal energy: Status and technology development

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.

    1982-01-01

    Point-focusing concentrators under consideration for solar thermal energy use are reviewed. These concentrators differ in such characteristics as optical configuration, optical materials, structure for support of the optical elements and of the receiver, mount, foundation, drive, controls and enclosure. Concentrator performance and cost are considered. Technology development is outlined, including wind loads and aerodynamics; precipitation, sand, and seismic considerations; and maintenance and cleaning.

  17. Experimental measurements of thermal properties of high-temperature refractory materials used for thermal energy storage

    NASA Astrophysics Data System (ADS)

    El-Leathy, Abdelrahman; Jeter, Sheldon; Al-Ansary, Hany; Abdel-Khalik, Said; Golob, Matthew; Danish, Syed Noman; Saeed, Rageh; Djajadiwinata, Eldwin; Al-Suhaibani, Zeyad

    2016-05-01

    This paper builds on studies conducted on thermal energy storage (TES) systems that were built as a part of the work performed for a DOE-funded SunShot project titled "High Temperature Falling Particle Receiver". In previous studies, two small-scale TES systems were constructed for measuring heat loss at high temperatures that are compatible with the falling particle receiver concept, both of which had shown very limited heat loss. Through the course of those studies, it became evident that there was a lack of information about the thermal performance of some of the insulating refractory materials used in the experiments at high temperatures, especially insulating firebrick and perlite concrete. This work focuses on determining the thermal conductivities of those materials at high temperatures. The apparatus consists of a prototype cylindrical TES bin built with the same wall construction used in previous studies. An electric heater is placed along the centerline of the bin, and thermocouples are used to measure temperature at the interfaces between all layers. Heat loss is measured across one of the layers whose thermal conductivity had already been well established using laboratory experiments. This value is used to deduce the thermal conductivity of other layers. Three interior temperature levels were considered; namely, 300°C, 500°C, and 700°C. Results show that the thermal conductivity of insulating firebrick remains low (approximately 0.22 W/m.K) at an average layer temperature as high as 640°C, but it was evident that the addition of mortar had an impact on its effective thermal conductivity. Results also show that the thermal conductivity of perlite concrete is very low, approximately 0.15 W/m.K at an average layer temperature of 360°C. This is evident by the large temperature drop that occurs across the perlite concrete layer. These results should be useful for future studies, especially those that focus on numerical modeling of TES bins.

  18. Thermal energy storage for industrial waste heat recovery

    NASA Technical Reports Server (NTRS)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    The potential is examined for waste heat recovery and reuse through thermal energy storage in five specific industrial categories: (1) primary aluminum, (2) cement, (3) food processing, (4) paper and pulp, and (5) iron and steel. Preliminary results from Phase 1 feasibility studies suggest energy savings through fossil fuel displacement approaching 0.1 quad/yr in the 1985 period. Early implementation of recovery technologies with minimal development appears likely in the food processing and paper and pulp industries; development of the other three categories, though equally desirable, will probably require a greater investment in time and dollars.

  19. Energy storage and thermal control system design status

    NASA Technical Reports Server (NTRS)

    Simons, Stephen N.; Willhoite, Bryan C.; Vanommering, Gert

    1989-01-01

    The Space Station Freedom electric power system (EPS) will initially rely on photovoltaics for power generation and Ni/H2 batteries for electrical energy storage. The current design for and the development status of two major subsystems in the PV Power Module is discussed. The energy storage subsystem comprised of high capacity Ni/H2 batteries and the single-phase thermal control system that rejects the excess heat generated by the batteries and other components associated with power generation and storage is described.

  20. United States Department of Energy Thermally Activated Heat Pump Program

    SciTech Connect

    Fiskum, R.J.; Adcock, P.W.; DeVault, R.C.

    1996-06-01

    The US Department of Energy (DOE) is working with partners from the gas heating and cooling industry to improve energy efficiency using advance absorption technologies, to eliminate chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), to reduce global warming through more efficient combustion of natural gas, and to impact electric peak demand of air conditioning. To assist industry in developing these gas heating and cooling absorption technologies, the US DOE sponsors the Thermally Activated Heat Pump Program. It is divided into five key activities, addressing residential gas absorption heat pumps, large commercial chillers, advanced absorption fluids, computer-aided design, and advanced ``Hi-Cool`` heat pumps.

  1. Product suitable for the storage and conveyance of thermal energy

    SciTech Connect

    Babin, L.; Clausse, D.

    1981-09-01

    This invention concerns the storage and conveyance of thermal energy at low temperature, by using the latent heat produced by a substance during changes of state. This substance consists of a salt producing considerable latent heat during change of state, such as NA/sub 2/SO/sub 4/, 10 H/sub 2/O, combined closely with a nucleating agent such as borax and dispersed in an oil to which an emulsifying agent has been added. This product is particularly suitable for storage of solar energy at low temperature and for heating of enclosed areas.

  2. Literature review of market studies of thermal energy storage

    SciTech Connect

    Hattrup, M.P.

    1988-02-01

    This report presents the results of a review of market studies of thermal energy storage (TES). This project was conducted by Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE). PNL staff reviewed and consolidated the findings of existing TES market studies conducted in the industrial, commercial, and residential sectors. The purpose of this project was to review and assess previous work and to use the information obtained to help provide direction for future technology transfer planning activities and to identify additional economic research needed within those three sectors. 37 refs.

  3. Thermal energy storage technologies for heating and cooling applications

    NASA Astrophysics Data System (ADS)

    Tomlinson, John J.

    1990-12-01

    Recent results from selected thermal energy storage (TES) research activities in Germany and Sweden are discussed. In addition, several new technologies for heating and cooling of buildings and automobiles were reviewed and found to benefit similar efforts in the United states. Details of a meeting with Didier-Werke AG, a leading German ceramics manufacturer who will provide TES media necessary for the United States to complete field tests of an advanced high temperature latent heat storage material, are presented. Finally, an overview of the December 1990 International Energy Agency (IEA) Executive Committee deliberations on TES is presented.

  4. Environmental risk assessment for aquifer thermal energy storage

    SciTech Connect

    Hall, S.H.

    1993-01-01

    This report has been prepared by Pacific Northwest Laboratory at the request of the International Energy Agency (IEA). The US Department of Energy represents the United States in the IEA for Annex IV, the IEA task for research and development in aquifer thermal energy storage (ATES). Installation and operation of an ATES system is necessarily intrusive to ground-water resources. Therefore, governmental authorities usually require an environmental risk assessment to be performed before permission to construct an ATES system is granted. Writing an accurate statement of risk presupposes a knowledge of aquifer and ground-water characteristics and that an engineering feasibility study has taken place. Effective and logical presentation of the results of the risk assessment can expedite the grant of approval. Introductory remarks should address questions regarding why the ATES project has been proposed, what it is expected to accomplish, and what the expected benefits are. Next, the system configuration, including the aquifer, ATES plant, and well field, should be described in terms of size and location, design components, and thermal and hydraulic capacity. The final element of system design, the predicted annual operating cycle, needs to be described in sufficient detail to allow the reviewer to appreciate the net hydraulic, thermal, and hydrochemical effects imposed on the aquifer. Risks may be environmental or legal. Only after a reviewer has been introduced to the proposed system`s design, operation, and scale can risk issues can be identified and weighed against the benefits of the proposed ATES system.

  5. Environmental risk assessment for aquifer thermal energy storage

    SciTech Connect

    Hall, S.H.

    1993-01-01

    This report has been prepared by Pacific Northwest Laboratory at the request of the International Energy Agency (IEA). The US Department of Energy represents the United States in the IEA for Annex IV, the IEA task for research and development in aquifer thermal energy storage (ATES). Installation and operation of an ATES system is necessarily intrusive to ground-water resources. Therefore, governmental authorities usually require an environmental risk assessment to be performed before permission to construct an ATES system is granted. Writing an accurate statement of risk presupposes a knowledge of aquifer and ground-water characteristics and that an engineering feasibility study has taken place. Effective and logical presentation of the results of the risk assessment can expedite the grant of approval. Introductory remarks should address questions regarding why the ATES project has been proposed, what it is expected to accomplish, and what the expected benefits are. Next, the system configuration, including the aquifer, ATES plant, and well field, should be described in terms of size and location, design components, and thermal and hydraulic capacity. The final element of system design, the predicted annual operating cycle, needs to be described in sufficient detail to allow the reviewer to appreciate the net hydraulic, thermal, and hydrochemical effects imposed on the aquifer. Risks may be environmental or legal. Only after a reviewer has been introduced to the proposed system's design, operation, and scale can risk issues can be identified and weighed against the benefits of the proposed ATES system.

  6. Thermal energy conversion by coupled shape memory and piezoelectric effects

    NASA Astrophysics Data System (ADS)

    Zakharov, Dmitry; Lebedev, Gor; Cugat, Orphee; Delamare, Jerome; Viala, Bernard; Lafont, Thomas; Gimeno, Leticia; Shelyakov, Alexander

    2012-09-01

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations.

  7. The transfer between electron bulk kinetic energy and thermal energy in collisionless magnetic reconnection

    SciTech Connect

    Lu, San; Lu, Quanming; Huang, Can; Wang, Shui

    2013-06-15

    By performing two-dimensional particle-in-cell simulations, we investigate the transfer between electron bulk kinetic and electron thermal energy in collisionless magnetic reconnection. In the vicinity of the X line, the electron bulk kinetic energy density is much larger than the electron thermal energy density. The evolution of the electron bulk kinetic energy is mainly determined by the work done by the electric field force and electron pressure gradient force. The work done by the electron gradient pressure force in the vicinity of the X line is changed to the electron enthalpy flux. In the magnetic island, the electron enthalpy flux is transferred to the electron thermal energy due to the compressibility of the plasma in the magnetic island. The compression of the plasma in the magnetic island is the consequence of the electromagnetic force acting on the plasma as the magnetic field lines release their tension after being reconnected. Therefore, we can observe that in the magnetic island the electron thermal energy density is much larger than the electron bulk kinetic energy density.

  8. Laser diode structures with a saturable absorber for high-energy picosecond optical pulse generation by combined gain-and Q-switching

    NASA Astrophysics Data System (ADS)

    Ryvkin, B. S.; Avrutin, E. A.; Kostamovaara, J. E. K.; Kostamovaara, J. T.

    2017-02-01

    The performance of gain-switched Fabry-Perot asymmetric-waveguide semiconductor lasers with a large equivalent spot size and an intracavity saturable absorber was investigated experimentally and theoretically. The laser with a short (˜20 μm) absorber emitted high-energy afterpulse-free optical pulses in a broad range of injection current pulse amplitudes; optical pulses with a peak power of about 35 W and a duration of about 80 ps at half maximum were achieved with a current pulse with an amplitude of just 8 A and a duration of 1.5 ns. Good quality pulsations were observed in a broad range of elevated temperatures. The introduction of a substantially longer absorber section leads to strong spectral broadening of the output without a significant improvement to pulse energy and peak power.

  9. First international comparison of primary absorbed dose to water standards in the medium-energy X-ray range

    NASA Astrophysics Data System (ADS)

    Büermann, Ludwig; Guerra, Antonio Stefano; Pimpinella, Maria; Pinto, Massimo; de Pooter, Jacco; de Prez, Leon; Jansen, Bartel; Denoziere, Marc; Rapp, Benjamin

    2016-01-01

    This report presents the results of the first international comparison of primary measurement standards of absorbed dose to water for the medium-energy X-ray range. Three of the participants (VSL, PTB, LNE-LNHB) used their existing water calorimeter based standards and one participant (ENEA) recently developed a new standard based on a water-graphite calorimeter. The participants calibrated three transfer chambers of the same type in terms of absorbed dose to water (NDw) and in addition in terms of air kerma (NK) using the CCRI radiation qualities in the range 100 kV to 250 kV. The additional NK values were intended to be used for a physical analysis of the ratios NDw/NK. All participants had previously participated in the BIPM.RI(I)-K3 key comparison of air kerma standards. Ratios of pairs of NMI's NK results of the current comparison were found to be consistent with the corresponding key comparison results within the expanded uncertainties of 0.6 % - 1 %. The NDw results were analysed in terms of the degrees of equivalence with the comparison reference values which were calculated for each beam quality as the weighted means of all results. The participant's results were consistent with the reference value within the expanded uncertainties. However, these expanded uncertainties varied significantly and ranged between about 1-1.8 % for the water calorimeter based standards and were estimated at 3.7 % for the water-graphite calorimeter. It was shown previously that the ratios NDw/NK for the type of ionization chamber used as transfer chamber in this comparison were very close (within less than 1 %) to the calculated values of (bar muen/ρ)w,ad, the mean values of the water-to-air ratio of the mass-energy-absorption coefficients at the depth d in water. Some of the participant's results deviated significantly from the expected behavior. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of

  10. THERMAL-ENERGY STORAGE IN A DEEP SANDSTONE AQUIFER IN MINNESOTA: FIELD OBSERVATIONS AND THERMAL ENERGY-TRANSPORT MODELING.

    USGS Publications Warehouse

    Miller, R.T.

    1986-01-01

    A study of the feasibility of storing heated water in a deep sandstone aquifer in Minnesota is described. The aquifer consists of four hydraulic zones that are areally anisotropic and have average hydraulic conductivities that range from 0. 03 to 1. 2 meters per day. A preliminary axially symmetric, nonisothermal, isotropic, single-phase, radial-flow, thermal-energy-transport model was constructed to investigate the sensitivity of model simulation to various hydraulic and thermal properties of the aquifer. A three-dimensional flow and thermal-energy transport model was constructed to incorporate the areal anisotropy of the aquifer. Analytical solutions of equations describing areally anisotropic groundwater flow around a doublet-well system were used to specify model boundary conditions for simulation of heat injection. The entire heat-injection-testing period of approximately 400 days was simulated. Model-computed temperatures compared favorably with field-recorded temperatures, with differences of no more than plus or minus 8 degree C. For each test cycle, model-computed aquifer thermal efficiency, defined as total heat withdrawn divided by total heat injected, was within plus or minus 2% of the field-calculated values.

  11. Numerical Modeling of a Shallow Borehole Thermal Energy Storage System

    NASA Astrophysics Data System (ADS)

    Catolico, N.; Ge, S.; Lu, N.; McCartney, J. S.

    2014-12-01

    Borehole thermal energy storage (BTES) combined with solar thermal energy harvesting is an economic technological system to garner and store energy as well as an environmentally-sustainable alternative for the heating of buildings. The first community-scale BTES system in North America was installed in 2007 in the Drake Landing Solar Community (DLSC), about 35 miles south of Calgary, Canada. The BTES system involves direct circulation of water heated from solar thermal panels in the summer into a storage tank, after which it is circulate within an array of 144 closed-loop geothermal heat exchangers having a depth of 35 m and a spacing of 2.5 m. In the winter the circulation direction is reversed to supply heat to houses. Data collection over a six year period indicates that this system can supply more than 90% of the winter heating energy needs for 52 houses in the community. One major challenge facing the BTES system technology is the relatively low annual efficiency, i.e., the ratio of energy input and output is in the range of 15% to 40% for the system in Drake Landing. To better understand the working principles of BTES and to improve BTES performance for future applications at larger scales, a three-dimensional transient coupled fluid and heat transfer model is established using TOUGH2. The time-dependent injection temperatures and circulation rate measured over the six years of monitoring are used as model input. The simulations are calibrated using soil temperature data measured at different locations over time. The time-dependent temperature distributions within the borehole region agree well with the measured temperatures for soil with an intrinsic permeability of 10e-19 m2, an apparent thermal conductivity of 2.03 W/m°C, and a volumetric heat capacity of 2.31 MJ/m-3°C. The calibrated model serves as the basis for a sensitivity analysis of soil and operational parameters on BTES system efficiency preformed with TOUGH2. Preliminary results suggest 1) BTES

  12. Thermal performance evaluation of Solar Energy Products Company (SEPCO) 'Soloron' collector tested outdoors

    NASA Technical Reports Server (NTRS)

    Chiou, J., Sr.

    1977-01-01

    The test article, Model EF-212, Serial Nr. 002, is a single glazed collector with a nonselective absorber plate, using flowing air as the heat transfer medium. The absorber plate and box frame are aluminum and the insulation is one inch isocyanurate foam board with thermal conductivity of 0.11 (BTU/sq ft Hr0/ft.) The tests included the following. (1) time constant test, (2) collector efficiency test, (3) collector stagnation test, (4) incident angle modifier test, (5) load test, (6) weathering test, and (7) absorber plate optical properties test. The results of these tests are tabulated, graphed, or otherwise recorded.

  13. Calculation of the absorbed dose and dose equivalent induced by medium energy neutrons and protons and comparison with experiment

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Bishop, B. L.

    1972-01-01

    Monte Carlo calculations have been carried out to determine the absorbed dose and dose equivalent for 592-MeV protons incident on a cylindrical phantom and for neutrons from 580-MeV proton-Be collisions incident on a semi-infinite phantom. For both configurations, the calculated depth dependence of the absorbed dose is in good agreement with experimental data.

  14. Thermal Energy Storage in a Confined Aquifer: Second Cycle

    NASA Astrophysics Data System (ADS)

    Molz, F. J.; Parr, A. D.; Andersen, P. F.

    1981-06-01

    During the first 6-month injection-storage-recovery cycle of the Auburn University Aquifer Thermal Energy Storage Project, water pumped from an upper supply aquifer was heated to an average temperature of 55°C with an oil-fired boiler and then injected into a lower storage aquifer. Injection and recovery temperatures, flow rates, and temperatures at six depths in 10 observation wells and hydraulic heads in seven wells were recorded twice daily. The second-cycle injection, which was performed in a manner similar to the first, began on September 23, 1978, and continued until November 25, 1978, when 58,010 m3 of water had been pumped into the storage aquifer. The major problem experienced during the first cycle, a clogging injection well, was reduced by regular backwashing. This was done 8 times during injection and resulted in a 24% average injection rate increase compared to the first cycle. A 63-day storage period ended on January 27, 1979, and production of hot water began with an initial temperature of 54°C. By March 23 this temperature had dropped to 33°C, with 66,400 m3 of water and 76% of the injected thermal energy recovered. This compares to 66% recovery during the first cycle over the same drop in production temperature. Production of hot water continued until April 20, at which time 100,100 m3 of water and 89% of the injected thermal energy was recovered at a final production temperature of 27.5°C. During the second cycle, measurements were made of relative land subsidence and rebound to a precision approaching 0.1 mm. The surface elevation near the injection well rose 4 mm during injection, fell during storage, and fell more rapidly toward its original elevation during production. This movement was due to thermal expansion and contraction rather than to effects caused by head changes in the storage aquifer.

  15. Design and testing of an energy-absorbing crewseat for the F/FB-111 aircraft. Volume 2: Data from seat testing

    NASA Technical Reports Server (NTRS)

    Shane, S. J.

    1985-01-01

    The unacceptably high injury rate during the escape sequence (including the ejection and ground impact) of the crew module for F/FB-111 aircraft is reviewed. A program to determine if the injury potential could be reduced by replacing the existing crewseats with energy absorbing crewseats is presented. An energy absorbing test seat is designed using much of the existing seat hardware. An extensive dynamic seat test series, designed to duplicate various crew module ground impact conditions is conducted at a sled test facility. Comparative tests with operational F-111 crewseats are also conducted. After successful dynamic testing of the seat, more testing is conducted with the seats mounted in an F-111 crew module. Both swing tests and vertical drop tests are conducted. The vertical drop tests are used to obtain comparative data between the energy absorbing and operational seats. Volume 1 describes the energy absorbing test seat and testing conducted, and evaluates the data from both test series. Volume 2 presents the data obtained during the seat test series, while Volume 3 presents the data from the crew module test series.

  16. Thermal Energy Harvesting Using Pyroelectric and Piezoelectric Effect

    NASA Astrophysics Data System (ADS)

    Kang, Miwon; Yeatman, Eric M.

    2016-11-01

    This paper presents a prototype of a thermal energy harvesting mechanism using both pyroelectric and piezoelectric effect. Thermal energy is one of abundant energy sources from various processes. Waste heat from a chip on a circuit board of the electronic device involves temperature differences from a few degrees C to over 100 °C. Therefore, 95 °C of a heat reservoir was used in this study. A repetitive time-dependant temperature variation is applied by a linear sliding table. The influence of heat conditions was investigated, by changing velocity and frequency of this linear sliding table. This energy harvesting mechanism employs Lead Zirconate Titanate (PZT-5H), a bimetal beam and two neodymium magnets. The pyroelectric effect is caused by a time-dependent temperature variation, and the piezoelectric effect is caused by stress from deformation of the bimetal. A maximum power output 0.54 μW is obtained at an optimal condition when the load resistance is 610 kΩ.

  17. System-Integrated Finite Element Analysis of a Full-Scale Helicopter Crash Test with Deployable Energy Absorbers

    NASA Technical Reports Server (NTRS)

    Annett, Martin S.; Polanco, Michael A.

    2010-01-01

    A full-scale crash test of an MD-500 helicopter was conducted in December 2009 at NASA Langley's Landing and Impact Research facility (LandIR). The MD-500 helicopter was fitted with a composite honeycomb Deployable Energy Absorber (DEA) and tested under vertical and horizontal impact velocities of 26-ft/sec and 40-ft/sec, respectively. The objectives of the test were to evaluate the performance of the DEA concept under realistic crash conditions and to generate test data for validation of a system integrated finite element model. In preparation for the full-scale crash test, a series of sub-scale and MD-500 mass simulator tests was conducted to evaluate the impact performances of various components, including a new crush tube and the DEA blocks. Parameters defined within the system integrated finite element model were determined from these tests. The objective of this paper is to summarize the finite element models developed and analyses performed, beginning with pre-test predictions and continuing through post-test validation.

  18. A direct measurement of the 6Li(n,t)4He cross section at sub-thermal neutron energy

    NASA Astrophysics Data System (ADS)

    Yue, A.; Dewey, M.; Gilliam, D.; Nico, J.; Greene, G.; Laptev, A.

    2014-09-01

    The thermal neutron capture cross section for the 6Li(n,t)4He reaction is an important neutron cross section standard. Yet few measurements of it have been performed and the ENDF/B-VII recommended value of (938 . 5 +/- 1 . 3) b is based heavily on measurements performed at higher energies. The first absolute, direct measurement of the 6Li(n,t)4He cross section at sub-thermal neutron energy has been performed at the NIST Center for Neutron Research. An alpha-gamma counter was used to measure the absolute neutron fluence of a monoenergetic neutron beam to sub-0.1% precision. The alpha-gamma counter used a thick, totally absorbing target of 10B-enriched boron carbide. The rate of absorbed neutrons was determined by counting the 478 keV 10B(n, γ)7Li gamma rays with calibrated high-purity germanium detectors. Simultaneously, the absolute rate of neutron-induced charged particles was measured for three thin 6Li targets of known density with a defined solid-angle counter. Using the known density of the 6Li targets and measurements of the rate of charged particles from the 6Li targets, the fluence of the neutron beam, and the energy of the neutron beam, we determine the 6Li(n,t)4He cross section at En = 3 . 3 meV to 0.3% uncertainty.

  19. Numerical modeling of Thermal Response Tests in Energy Piles

    NASA Astrophysics Data System (ADS)

    Franco, A.; Toledo, M.; Moffat, R.; Herrera, P. A.

    2013-05-01

    Nowadays, thermal response tests (TRT) are used as the main tools for the evaluation of low enthalpy geothermal systems such as heat exchangers. The results of TRT are used for estimating thermal conductivity and thermal resistance values of those systems. We present results of synthetic TRT simulations that model the behavior observed in an experimental energy pile system, which was installed at the new building of the Faculty of Engineering of Universidad de Chile. Moreover, we also present a parametric study to identify the most influent parameters in the performance of this type of tests. The modeling was developed using the finite element software COMSOL Multiphysics, which allows the incorporation of flow and heat transport processes. The modeled system consists on a concrete pile with 1 m diameter and 28 m deep, which contains a 28 mm diameter PEX pipe arranged in a closed circuit. Three configurations were analyzed: a U pipe, a triple U and a helicoid shape implemented at the experimental site. All simulations were run considering transient response in a three-dimensional domain. The simulation results provided the temperature distribution on the pile for a set of different geometry and physical properties of the materials. These results were compared with analytical solutions which are commonly used to interpret TRT data. This analysis demonstrated that there are several parameters that affect the system response in a synthetic TRT. For example, the diameter of the simulated pile affects the estimated effective thermal conductivity of the system. Moreover, the simulation results show that the estimated thermal conductivity for a 1 m diameter pile did not stabilize even after 100 hours since the beginning of the test, when it reached a value 30% below value used to set up the material properties in the simulation. Furthermore, we observed different behaviors depending on the thermal properties of concrete and soil. According to the simulations, the thermal

  20. PCM/ graphite foam composite for thermal energy storage device

    NASA Astrophysics Data System (ADS)

    Guo, C. X.; Ma, X. L.; Yang, L.

    2015-07-01

    Numerical studies are proposed to predict and investigate the thermal characteristics of a thermal storage device consists of graphite foam matrix saturated with phase change material, PCM. The composite (graphite foam matrix saturated with PCM) is prepared by impregnation method under vacuum condition, and then is introduced into a cylindrical shell and tube device while it experiences its heat from an inner tube fluid. The two-dimensional numerical simulation is performed using the volume averaging technique; while the phases change process is modelled using the enthalpy porosity method. A series of numerical calculations have been done in order to analyze the influence of fluid operating conditions on the melting process of the paraffin/graphite foam. The results are given in terms of temperature or liquid fraction time history in paraffin/graphite foam composite, which show that the heat transfer rate of the device is effectively improved due to the high thermal conductivity of graphite foams. Therefore, paraffin/graphite foam composite can be considered as suitable candidates for latent heat thermal energy storage device.

  1. Characterization of an energy storage capacitor in abnormal thermal environments

    SciTech Connect

    Edwards, L.R.; Chen, K.C.; Baron, R.V.

    2000-01-05

    There are applications of high-voltage, energy-storage, capacitors where it is desirable that the energy storage capability can be reliably and predictably negated in abnormal environments such as fire. This property serves as a safety feature to prevent events of unintended consequence. The present paper describes studies of the thermal response characteristics of a cylindrically wound, discrete Mylar film/foil capacitor design. The experimental setups that simulate fires will be presented. Three different heat input geometries were employed: uniform radial input, spot radial input, and axial input. Heat input was controlled via feedback system to maintain specific temperature ramp rates. Both capacitor voltage and current were monitored during the thermal excursion to ascertain the failure temperature, i.e. when the capacitor permanently shorts. Temperature of failure data is presented for the three heat input cases along with a statistical analysis of the results and application implications. The physics of failure will be described in terms of the thermal/mechanical properties of the Mylar.

  2. Sodium-based hydrides for thermal energy applications

    NASA Astrophysics Data System (ADS)

    Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

    2016-04-01

    Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

  3. Advanced Reactors Thermal Energy Transport for Process Industries

    SciTech Connect

    P. Sabharwall; S.J. Yoon; M.G. McKellar; C. Stoots; George Griffith

    2014-07-01

    The operation temperature of advanced nuclear reactors is generally higher than commercial light water reactors and thermal energy from advanced nuclear reactor can be used for various purposes such as liquid fuel production, district heating, desalination, hydrogen production, and other process heat applications, etc. Some of the major technology challenges that must be overcome before the advanced reactors could be licensed on the reactor side are qualification of next generation of nuclear fuel, materials that can withstand higher temperature, improvement in power cycle thermal efficiency by going to combined cycles, SCO2 cycles, successful demonstration of advanced compact heat exchangers in the prototypical conditions, and from the process side application the challenge is to transport the thermal energy from the reactor to the process plant with maximum efficiency (i.e., with minimum temperature drop). The main focus of this study is on doing a parametric study of efficient heat transport system, with different coolants (mainly, water, He, and molten salts) to determine maximum possible distance that can be achieved.

  4. Equilibrium statistical-thermal models in high-energy physics

    NASA Astrophysics Data System (ADS)

    Tawfik, Abdel Nasser

    2014-05-01

    We review some recent highlights from the applications of statistical-thermal models to different experimental measurements and lattice QCD thermodynamics that have been made during the last decade. We start with a short review of the historical milestones on the path of constructing statistical-thermal models for heavy-ion physics. We discovered that Heinz Koppe formulated in 1948, an almost complete recipe for the statistical-thermal models. In 1950, Enrico Fermi generalized this statistical approach, in which he started with a general cross-section formula and inserted into it, the simplifying assumptions about the matrix element of the interaction process that likely reflects many features of the high-energy reactions dominated by density in the phase space of final states. In 1964, Hagedorn systematically analyzed the high-energy phenomena using all tools of statistical physics and introduced the concept of limiting temperature based on the statistical bootstrap model. It turns to be quite often that many-particle systems can be studied with the help of statistical-thermal methods. The analysis of yield multiplicities in high-energy collisions gives an overwhelming evidence for the chemical equilibrium in the final state. The strange particles might be an exception, as they are suppressed at lower beam energies. However, their relative yields fulfill statistical equilibrium, as well. We review the equilibrium statistical-thermal models for particle production, fluctuations and collective flow in heavy-ion experiments. We also review their reproduction of the lattice QCD thermodynamics at vanishing and finite chemical potential. During the last decade, five conditions have been suggested to describe the universal behavior of the chemical freeze-out parameters. The higher order moments of multiplicity have been discussed. They offer deep insights about particle production and to critical fluctuations. Therefore, we use them to describe the freeze-out parameters

  5. Thermal energy storage. [by means of chemical reactions

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.

    1975-01-01

    The principles involved in thermal energy storage by sensible heat, chemical potential energy, and latent heat of fusion are examined for the purpose of evolving selection criteria for material candidates in the low ( 0 C) and high ( 100 C) temperature ranges. The examination identifies some unresolved theoretical considerations and permits a preliminary formulation of an energy storage theory. A number of candidates in the low and high temperature ranges are presented along with a rating of candidates or potential candidates. A few interesting candidates in the 0 to 100 C region are also included. It is concluded that storage by means of reactions whose reversibility can be controlled either by product removal or by catalytic means appear to offer appreciable advantages over storage with reactions whose reversability cannot be controlled. Among such advantages are listed higher heat storage capacities and more favorable options regarding temperatures of collection, storage, and delivery. Among the disadvantages are lower storage efficiencies.

  6. A buckling region in locust hindlegs contains resilin and absorbs energy when jumping or kicking goes wrong.

    PubMed

    Bayley, T G; Sutton, G P; Burrows, M

    2012-04-01

    If a hindleg of a locust slips during jumping, or misses its target during kicking, energy generated by the two extensor tibiae muscles is no longer expended in raising the body or striking a target. How, then, is the energy in a jump (4100-4800 μJ) or kick (1700 μJ) dissipated? A specialised buckling region found in the proximal hind-tibia where the bending moment is high, but not present in the other legs, buckled and allowed the distal part of the tibia to extend. In jumps when a hindleg slipped, it bent by a mean of 23±14 deg at a velocity of 13.4±9.5 deg ms(-1); in kicks that failed to contact a target it bent by 32±16 deg at a velocity of 32.9±9.5 deg ms(-1). It also buckled 8.5±4.0 deg at a rate of 0.063±0.005 deg ms(-1) when the tibia was prevented from flexing fully about the femur in preparation for both these movements. By experimentally buckling this region through 40 deg at velocities of 0.001-0.65 deg ms(-1), we showed that one hindleg could store about 870 μJ on bending, of which 210 μJ was dissipated back to the leg on release. A band of blue fluorescence was revealed at the buckling region under UV illumination that had the two key signatures of the elastic protein resilin. A group of campaniform sensilla 300 μm proximal to the buckling region responded to imposed buckling movements. The features of the buckling region show that it can act as a shock absorber as proposed previously when jumping and kicking movements go wrong.

  7. Butterfly micro bilayer thermal energy harvester geometry with improved performances

    NASA Astrophysics Data System (ADS)

    Trioux, E.; Monfray, S.; Basrour, S.

    2016-11-01

    This paper reports the recent progress of a new technology to scavenge thermal energy, implying a double-step transduction through thermal buckling of a bilayer aluminum nitride / aluminum bridge and piezoelectric transduction. A completely new scavenger design is presented, improving greatly its final performance. The butterfly shape reduces the overall device mechanical rigidity, which leads to a decrease of buckling temperatures compared to previously studied rectangular plates. In a first time we compared performances of rectangular and butterfly plates with an equal thickness of Al and AlN. In a second time, with a thicker Al layer than AlN layer, we will study only butterfly structure in terms of output power and buckling temperatures, and compare it to the previous stack.

  8. A survey of manufacturers of solar thermal energy systems

    NASA Technical Reports Server (NTRS)

    Levine, N.; Slonski, M. L.

    1982-01-01

    Sixty-seven firms that had received funding for development of solar thermal energy systems (STES) were surveyed. The effect of the solar thermal technology systems program in accelerating (STES) were assessed. The 54 firms still developing STES were grouped into a production typology comparing the three major technologies with three basic functions. It was discovered that large and small firms were developing primarily central receiver systems, but also typically worked on more than one technology. Most medium-sized firms worked only on distributed systems. Federal support of STES was perceived as necessary to allow producers to take otherwise unacceptable risks. Approximately half of the respondents would drop out of STES if support were terminated, including a disproportionate number of medium-sized firms. A differentiated view of the technology, taking into account differing firm sizes and the various stages of technology development, was suggested for policy and planning purposes.

  9. Development of thermal energy storage materials for biomedical applications.

    PubMed

    Shukla, A; Sharma, Atul; Shukla, Manjari; Chen, C R

    2015-01-01

    The phase change materials (PCMs) have been utilized widely for solar thermal energy storage (TES) devices. The quality of these materials to remain at a particular temperature during solid-liquid, liquid-solid phase transition can also be utilized for many biomedical applications as well and has been explored in recent past already. This study reports some novel PCMs developed by them, along with some existing PCMs, to be used for such biomedical applications. Interestingly, it was observed that the heating/cooling properties of these PCMs enhance the quality of a variety of biomedical applications with many advantages (non-electric, no risk of electric shock, easy to handle, easy to recharge thermally, long life, cheap and easily available, reusable) over existing applications. Results of the present study are quite interesting and exciting, opening a plethora of opportunities for more work on the subject, which require overlapping expertise of material scientists, biochemists and medical experts for broader social benefits.

  10. On thermal properties of hard rocks as a host environment of an underground thermal energy storage

    NASA Astrophysics Data System (ADS)

    Novakova, L.; Hladky, R.; Broz, M.; Novak, P.; Lachman, V.; Sosna, K.; Zaruba, J.; Metelkova, Z.; Najser, J.

    2013-12-01

    With increasing focus on environmentally friendly technologies waste heat recycling became an important issue. Under certain circumstances subsurface environment could be utilized to accommodate relatively large quantity of heat. Industrial waste heat produced during warm months can be stored in an underground thermal energy storage (UTES) and used when needed. It is however a complex task to set up a sustainable UTES for industrial scale. Number of parameters has to be studied and evaluated by means of thermohydromechanical and chemical coupling (THMC) before any UTES construction. Thermal characteristics of various rocks and its stability under thermal loading are amongst the most essential. In the Czech Republic study two complementary projects THMC processes during an UTES operation. The RESEN project (www.resen.cz) employs laboratory tests and experiments to characterise thermal properties of hard rocks in the Bohemian Massif. Aim of the project is to point out the most suitable rock environment in the Bohemian Massif for moderate to ultra-high temperature UTES construction (Sanyal, 2005). The VITA project (www.geology.cz/mokrsko) studies THM coupling in non-electrical temperature UTES using long term in-situ experiment. In both projects thermal properties of rocks were studied. Thermal conductivity and capacity were measured on rock samples. In addition an influence of increasing temperature and moisture content was considered. Ten hard rocks were investigated. The set included two sandstones, two ignibrites, a melaphyr, a syenite, two granites, a gneiss and a serpentinite. For each rock there were measured thermal conductivity and capacity of at least 54 dried samples. Subsequently, the samples were heated up to 380°C in 8 hours and left to cool down. Thermal characteristics were measured during the heating period and after the sample reached room temperature. Heating and cooling cycle was repeated 7 to 10 times to evaluate possible UTES-like degradation of

  11. U.S. Department of Energy thermal energy storage research activities review: 1989 Proceedings

    SciTech Connect

    Hoffman, H.W.; Tomlinson, J.J.

    1989-03-01

    Thermal Energy Storage (TES) offers the opportunity for the recovery and re-use of heat currently rejected to the ambient environment. Further, through the ability of TES to match an energy supply with a thermal energy demand, TES increases efficiencies of energy systems and improves capacity factors of power plants. The US Department of Energy has been the leader in TES research, development, and demonstration since recognition in 1976 of the need for fostering energy conservation as a component of the national energy budget. The federal program on TES R and D is the responsibility of the Office of Energy Storage and Distribution within the US Department of Energy (DOE). The overall program is organized into three program areas: diurnal--relating primarily to lower temperature heat for use in residential and commercial buildings on a daily cycle; industrial--relating primarily to higher temperature heat for use in industrial and utility processes on an hourly to daily cycle; seasonal--relating primarily to lower temperature heat or chill for use in residential complexes (central supply as for apartments or housing developments), commercial (light manufacturing, processing, or retail), and industrial (space conditioning) on a seasonal to annual cycle. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  12. Thermal Energy Corporation Combined Heat and Power Project

    SciTech Connect

    Turner, E. Bruce; Brown, Tim; Mardiat, Ed

    2011-12-31

    To meet the planned heating and cooling load growth at the Texas Medical Center (TMC), Thermal Energy Corporation (TECO) implemented Phase 1 of a Master Plan to install an additional 32,000 tons of chilled water capacity, a 75,000 ton-hour (8.8 million gallon) Thermal Energy Storage (TES) tank, and a 48 MW Combined Heat and Power (CHP) system. The Department of Energy selected TMC for a $10 million grant award as part of the Financial Assistance Funding Opportunity Announcement, U.S. Department of Energy National Energy Technology, Recovery Act: Deployment of Combined Heat and Power (CHP) Systems, District Energy Systems, Waste Energy Recovery Systems, and Efficiency Industrial Equipment Funding Opportunity Number: DE-FOA-0000044 to support the installation of a new 48 MW CHP system at the TMC located just outside downtown Houston. As the largest medical center in the world, TMC is home to many of the nation's best hospitals, physicians, researchers, educational institutions, and health care providers. TMC provides care to approximately six million patients each year, and medical instruction to over 71,000 students. A medical center the size of TMC has enormous electricity and thermal energy demands to help it carry out its mission. Reliable, high-quality steam and chilled water are of utmost importance to the operations of its many facilities. For example, advanced medical equipment, laboratories, laundry facilities, space heating and cooling all rely on the generation of heat and power. As result of this project TECO provides this mission critical heating and cooling to TMC utilizing a system that is both energy-efficient and reliable since it provides the capability to run on power independent of the already strained regional electric grid. This allows the medical center to focus on its primary mission providing top quality medical care and instruction without worrying about excessive energy costs or the loss of heating and cooling due to the risk of power

  13. Nanofluid heat transfer under mixed convection flow in a tube for solar thermal energy applications.

    PubMed

    Sekhar, Y Raja; Sharma, K V; Kamal, Subhash

    2016-05-01

    The solar flat plate collector operating under different convective modes has low efficiency for energy conversion. The energy absorbed by the working fluid in the collector system and its heat transfer characteristics vary with solar insolation and mass flow rate. The performance of the system is improved by reducing the losses from the collector. Various passive methods have been devised to aid energy absorption by the working fluid. Also, working fluids are modified using nanoparticles to improve the thermal properties of the fluid. In the present work, simulation and experimental studies are undertaken for pipe flow at constant heat flux boundary condition in the mixed convection mode. The working fluid at low Reynolds number in the mixed laminar flow range is undertaken with water in thermosyphon mode for different inclination angles of the tube. Local and average coefficients are determined experimentally and compared with theoretical values for water-based Al2O3 nanofluids. The results show an enhancement in heat transfer in the experimental range with Rayleigh number at higher inclinations of the collector tube for water and nanofluids.

  14. Feasibility study of thermal energy harvesting using lead free pyroelectrics

    NASA Astrophysics Data System (ADS)

    Karim, Hasanul; Sarker, Md Rashedul H.; Shahriar, Shaimum; Arif Ishtiaque Shuvo, Mohammad; Delfin, Diego; Hodges, Deidra; (Bill Tseng, Tzu-Liang; Roberson, David; Love, Norman; Lin, Yirong

    2016-05-01

    Energy harvesting has significant potential for applications in energizing wireless sensors and charging energy storage devices. To date, one of the most widely investigated materials for mechanical and thermal energy harvesting is lead zirconate titanate (PZT). However, lead has detrimental effects on the environment and on health. Hence, alternative materials are required for this purpose. In this paper, a lead free material, lithium niobate (LNB) is investigated as a potential material for pyroelectric energy harvesting. Although its theoretical pyroelectric properties are lower compared to PZT, it has better properties than other lead free alternatives such as ZnO. In addition, LNB has a high Curie temperature of about 1142 °C, which makes it applicable for high temperature energy harvesting, where other pyroelectric ceramics are not suitable. Herein, an energy harvesting and storage system composed of a single crystal LNB and a porous carbon-based super-capacitor was investigated. It is found that with controlled heating and cooling, a single wafer of LNB (75 mm diameter and 0.5 mm thickness) could generate 437.72 nW cm-3 of power and it could be used to charge a super-capacitor with a charging rate of 2.63 mV (h cm3)-1.

  15. On the rate of energy input in thermal solar flares

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Mckenzie, D. L.

    1984-01-01

    The rise phases of solar soft X-ray flares observed by X-ray crystal spectrometers on P78-1 are discussed in terms of the rate of change of X-ray flux as a function of time. It is shown that the flux increases exponentially over most of the rise time. The e-folding time (tau) has a cutoff at approximately 13 s. Soft X-ray flares with smaller values of tau are not observed. It is suggested that this phenomenon is due to the ability of the solar atmosphere to absorb the input energy and convert it into a typical soft X-ray flare, when the value of tau is greater than about 13 s. For energy input rates with tau greater than about 13 s, the temperature attained by the plasma is typically around 2 x 10 to the 7th K, but for values of tau less than 13 s, the gas is heated to much higher temperatures (about 10 to the 8th K), producing a certain class of hard X-ray flares.

  16. Discharge Flux Variability in Stored Thermal Energy Cookstoves

    NASA Astrophysics Data System (ADS)

    Bryant, Michael James

    A thermal analysis and test is performed to determine flux and temperature variability for Phase change thermal energy to investigation feasibility of use in a Stored Thermal Energy Cookstove (STEC). The phase change material (PCM) NaNO3-KNO3 Eutectic (52:48) Solar Salt is identified for energy storage in STEC due to a melting temperature of 222°C which is deemed appropriate for use in cooking up to temperatures of 200°C +/- 20°C. 1-D planar and cylindrical analytical multiphase solutions are correlated with a transient non-linear ANSYS Finite Element Model (FEM). 1-D idealized models of planar and cylindrical analytical multiphase solutions show the flux stability of cylindrical solidification is twice that of planar solidification. Flux drops a linear average of 0.5%/min in the last half hour of a one hour cooking session in cylindrical solidification vs 1%/min in planar solidification under a constant temperature (dirichlet) boundary condition of 42°C below the melting point of the PCM. Solidification progresses more quickly in the planar case yielding a solid PCM thickness of 3.3 cm after one hour vs 2.4 cm in the cylindrical case. A test is performed on a simplified simple STEC apparatus to investigate cooling rates of the cooking surface while boiling water. 0.5L of water is brought to boil from room temperature with a linear average cooking surface flux of 21,000 W/m2 and a cooking surface cooling rate of 3.8°C/min. Results show increasing the thermal conductivity of the PCM and reducing the total thickness of the solidifying PCM layer before and after discharge will reduce cooling rates, improve stability of the flux delivery device, and increase feasibility of use. Pursuing lower flux cooking and non-cooking applications may increase likelihood of adoption by reducing thermal gradients during discharge. A proposal to explore further development of STEC to aid adoption is discussed.

  17. Electromagnetic power absorber

    NASA Technical Reports Server (NTRS)

    Iwasaki, R. S. (Inventor)

    1979-01-01

    A structure is presented with a surface portion of dielectric material which passes electromagnetic radiation and with a portion below the surface which includes material that absorbs the radiation, the face of the structure being formed with numerous steep ridges. The steepness of the dielectric material results in a high proportion of the electromagnetic energy passing through the surface for absorption by the absorbing material under the surface. A backing of aluminum or other highly heat-conductive and reflective material lies under the face and has very steep protuberances supporting the absorbing and dielectric materials.

  18. Evaluation of diurnal thermal energy storage combined with cogeneration systems

    NASA Astrophysics Data System (ADS)

    Somasundaram, S.; Brown, D. R.; Drost, M. K.

    1992-11-01

    This report describes the results of an evaluation of thermal energy storage (TES) integrated with simple gas turbine cogeneration systems. The TES system captures and stores thermal energy from the gas turbine exhaust for immediate or future generation of process heat. Integrating thermal energy storage with conventional cogeneration equipment increases the initial cost of the combined system; but, by decoupling electric power and process heat production, the system offers the following significant advantages: (1) electric power can be generated on demand, irrespective of the process heat load profile, thus increasing the value of the power produced; (2) although supplementary firing could be used to serve independently varying electric and process heat loads, this approach is inefficient. Integrating TES with cogeneration can serve the two independent loads while firing all fuel in the gas turbine. The study evaluated the cost of power produced by cogeneration and cogeneration/TES systems designed to serve a fixed process steam load. The value of the process steam was set at the levelized cost estimated for the steam from a conventional stand-alone boiler. Power costs for combustion turbine and combined-cycle power plants were also calculated for comparison. The results indicated that peak power production costs for the cogeneration/TES systems were between 25 and 40 percent lower than peak power costs estimated for a combustion turbine and between 15 and 35 percent lower than peak power costs estimated for a combined-cycle plant. The ranges reflect differences in the daily power production schedule and process steam pressure/temperature assumptions for the cases evaluated. Further cost reductions may result from optimization of current cogeneration/TES system designs and improvement in TES technology through future research and development.

  19. Solar-thermal-energy collection/storage-pond system

    DOEpatents

    Blahnik, D.E.

    1982-03-25

    A solar thermal energy collection and storage system is disclosed. Water is contained, and the water surface is exposed directly to the sun. The central part of an impermeable membrane is positioned below the water's surface and above its bottom with a first side of the membrane pointing generally upward in its central portion. The perimeter part of the membrane is placed to create a watertight boundary separating the water into a first volume which is directly exposable to the sun and which touches the membranes first side, and a second volumn which touches the membranes second side. A salt is dissolved in the first water volume.

  20. Carbon dioxide release from ocean thermal energy conversion (OTEC) cycles

    SciTech Connect

    Green, H.J. ); Guenther, P.R. )

    1990-09-01

    This paper presents the results of recent measurements of CO{sub 2} release from an open-cycle ocean thermal energy conversion (OTEC) experiment. Based on these data, the rate of short-term CO{sub 2} release from future open-cycle OTEC plants is projected to be 15 to 25 times smaller than that from fossil-fueled electric power plants. OTEC system that incorporate subsurface mixed discharge are expected to result in no long-term release. OTEC plants can significantly reduce CO{sub 2} emissions when substituted for fossil-fueled power generation. 12 refs., 4 figs., 3 tabs.

  1. Thermal energy storage units for solar electric power plants

    NASA Astrophysics Data System (ADS)

    Gudkov, V. I.; Chakalev, K. N.

    Several types of heat storage units for solar power plants with thermodynamic cycles of energy conversion are examined, including specific-heat units (particularly water-vapor devices), thermochemical units, and phase-change units. The dependence of specific capital costs for heat storage units upon time of operation is discussed, and particular consideration is give to types of connections of specific-heat units into the thermal circuit of a power plant, and to a phase-change unit that uses a heat pipe for internal heat transport.

  2. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  3. Heat transfer research for ocean thermal energy conversion

    SciTech Connect

    Kreith, F.; Bharathan, D.

    1988-02-01

    In this lecture an overview of the heat and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems, are briefly discussed.

  4. Heat transfer research for ocean thermal energy conversion

    NASA Astrophysics Data System (ADS)

    Kreith, F.; Bharathan, D.

    1987-03-01

    In this lecture an overview of the heat- and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open- and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems are briefly discussed.

  5. Bibliography of the seasonal thermal energy storage library

    SciTech Connect

    Prater, L.S.; Casper, G.; Kawin, R.A.

    1981-08-01

    The Main Listing is arranged alphabetically by the last name of the first author. Each citation includes the author's name, title, publisher, publication date, and where applicable, the National Technical Information Service (NTIS) number or other document number. The number preceding each citation is the identification number for that document in the Seasonal Thermal Energy Storage (STES) Library. Occasionally, one or two alphabetic characters are added to the identification number. These alphabetic characters indicate that the document is contained in a collection of papers, such as the proceedings of a conference. An Author Index and an Identification Number Index are included. (WHK)

  6. Alkali Metal/Salt Thermal-Energy-Storage Systems

    NASA Technical Reports Server (NTRS)

    Phillips, Wayne W.; Stearns, John W.

    1987-01-01

    Proposed thermal-energy-storage system based on mixture of alkali metal and one of its halide salts; metal and salt form slurry of two immiscible melts. Use of slurry expected to prevent incrustations of solidified salts on heat-transfer surfaces that occur where salts alone used. Since incrustations impede heat transfer, system performance improved. In system, charging heat-exchanger surface immersed in lower liquid, rich in halide-salt, phase-charge material. Discharging heat exchanger surface immersed in upper liquid, rich in alkali metal.

  7. Electrochemical energy storage systems for solar thermal applications

    NASA Technical Reports Server (NTRS)

    Krauthamer, S.; Frank, H.

    1980-01-01

    Existing and advanced electrochemical storage and inversion/conversion systems that may be used with terrestrial solar-thermal power systems are evaluated. The status, cost and performance of existing storage systems are assessed, and the cost, performance, and availability of advanced systems are projected. A prime consideration is the cost of delivered energy from plants utilizing electrochemical storage. Results indicate that the five most attractive electrochemical storage systems are the: iron-chromium redox (NASA LeRC), zinc-bromine (Exxon), sodium-sulfur (Ford), sodium-sulfur (Dow), and zinc-chlorine (EDA).

  8. Analysis of dynamic effects in solar thermal energy conversion systems

    NASA Technical Reports Server (NTRS)

    Hamilton, C. L.

    1978-01-01

    The paper examines a study the purpose of which is to assess the performance of solar thermal power systems insofar as it depends on the dynamic character of system components and the solar radiation which drives them. Using a dynamic model, the daily operation of two conceptual solar conversion systems was simulated under varying operating strategies and several different time-dependent radiation intensity functions. These curves ranged from smoothly varying input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours.

  9. Induction of Nonphotochemical Energy Dissipation and Absorbance Changes in Leaves (Evidence for Changes in the State of the Light-Harvesting System of Photosystem II in Vivo).

    PubMed Central

    Ruban, A. V.; Young, A. J.; Horton, P.

    1993-01-01

    Simultaneous measurements of nonphotochemical quenching of chlorophyll fluorescence and absorbance changes in the 400- to 560-nm region have been made following illumination of dark-adapted leaves of the epiphytic bromeliad Guzmania monostachia. During the first illumination, an absorbance change at 505 nm occurred with a half-time of 45 s as the leaf zeaxanthin content rose to 14% of total leaf carotenoid. Selective light scattering at 535 nm occurred with a half-time of 30 s. During a second illumination, following a 5-min dark period, quenching and the 535-nm absorbance change occurred more rapidly, reaching a maximum extent within 30 s. Nonphotochemical quenching of chlorophyll fluorescence was found to be linearly correlated to the 535-nm absorbance change throughout. Examination of the spectra of chlorophyll fluorescence emission at 77 K for leaves sampled at intervals during this regime showed selective quenching in the light-harvesting complexes of photosystem II (LHCII). The quenching spectrum of the reversible component of quenching had a maximum at 700 nm, indicating quenching in aggregated LHCII, whereas the irreversible component represented a quenching of 680-nm fluorescence from unaggregated LHCII. It is suggested that this latter process, which is associated with the 505-nm absorbance change and zeaxanthin formation, is indicating a change in state of the LHCII complexes that is necessary to amplify or activate reversible pH-dependent energy dissipation, which is monitored by the 535-nm absorbance change. Both of the major forms of nonphotochemical energy dissipation in vivo are therefore part of the same physiological photoprotective process and both result from alterations in the LHCII system. PMID:12231862

  10. Observation of thermal effects due to an optical incident signal and high fluence on InGaAs/InP multiple-quantum-well saturable absorber nonlinear mirrors: evolution of characteristics and time constants.

    PubMed

    Le Cren, Elodie; Lobo, Sébastien; Fève, Sylvain; Simon, Jean-Claude

    2006-09-10

    We observe the effects of a temperature increase on the characteristics of an InGaAs/InP multiple-quantum-well (MQW) saturable absorber (SA) in a microcavity provided by an optical input signal under normal incidence. The temperature increase on the nonlinear mirror (NLM) due to an optical signal depends on the energy time filling factor (FF) of this input signal (analogous to the signal's duty cycle, which is the ratio between the repetition period and the pulse duration) and hence depends on the repetition rate of the signal for a given pulse time width. This increase in temperature is mostly responsible for a shift in the reflectivity spectrum of the device toward higher wavelengths. In this experimental study, we show the shift of the resonance cavity versus the optical input power at high FF, and we evaluate the thermal time constant of an Fe-doped InGaAs/InP MQW NLM. Finally, we report the consequences of such thermal effects and high fluence on the reflectivity and contrast of two different InGaAs/InP NLMs when the input signal FF rises up to 25%, which gets close to telecommunication transmission conditions.

  11. Conceptual design of thermal energy storage systems for near-term electric utility applications

    NASA Technical Reports Server (NTRS)

    Hall, E. W.

    1980-01-01

    Promising thermal energy storage systems for midterm applications in conventional electric utilities for peaking power generation are evaluated. Conceptual designs of selected thermal energy storage systems integrated with conventional utilities are considered including characteristics of alternate systems for peaking power generation, viz gas turbines and coal fired cycling plants. Competitive benefit analysis of thermal energy storage systems with alternate systems for peaking power generation and recommendations for development and field test of thermal energy storage with a conventional utility are included. Results indicate that thermal energy storage is only marginally competitive with coal fired cycling power plants and gas turbines for peaking power generation.

  12. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    PubMed

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  13. Preparation and Thermal Characterization of Nitrates/Expanded Graphite Composite Phase-Change Material for Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    Li, Y.; Li, P.; Zhu, Q. Z.; Li, Q. F.

    2016-11-01

    Molten nitrate is widely used as thermal storage medium in the solar thermal power plants for its appropriate phase-change temperature, high heat storage density and low cost, etc. But its low thermal conductivity, heat absorbing and releasing rate limited its application. Expanded graphite (EG) can compensate the low thermal conductivity of nitrate. In this study, binary nitrates at the weight ratio of 4:6 for LiNO3:KNO3 were prepared using static mixed melting method. EG with the mass fraction of 5 %, 10 %, 15 %, 20 % and 30 % was used to enhance the thermal conductivity. The compound of nitrates/EG was prepared using the ultrasonic smashing method. The thermal conductivity of binary nitrates, EG and nitrates/EG composite was measured by the transient plane heat source technique (TPS). The thermal behaviors were analyzed with a differential scanning calorimeter (DSC). Results showed that the addition of EG significantly enhanced the thermal conductivity, e.g., the thermal conductivity of 10 wt% EG composite phase-change material (PCM) is 8.5 W(m{^{-1}} K{^{-1}}) to 9.5 W(m{^{-1}}K{^{-1}}), which is about eight times larger than that of binary nitrates. To observe the combination morphology, pure EG, nitrates/EG composite PCM and binary nitrates were characterized using scanning electron microscope (SEM). The thermal reliability of the binary nitrates and the composite PCM was determined by DSC. Thermal cycling test showed that both binary nitrates and nitrates/EG composite material have good thermal reliability.

  14. A novel application of concentrated solar thermal energy in foundries.

    PubMed

    Selvaraj, J; Harikesavan, V; Eshwanth, A

    2016-05-01

    Scrap preheating in foundries is a technology that saves melting energy, leading to economic and environmental benefits. The proposed method in this paper utilizes solar thermal energy for preheating scrap, effected through a parabolic trough concentrator that focuses sunlight onto a receiver which carries the metallic scrap. Scraps of various thicknesses were placed on the receiver to study the heat absorption by them. Experimental results revealed the pattern with which heat is gained by the scrap, the efficiency of the process and how it is affected as the scrap gains heat. The inferences from them gave practical guidelines on handling scraps for best possible energy savings. Based on the experiments conducted, preheat of up to 160 °C and a maximum efficiency of 70 % and a minimum efficiency of 40 % could be achieved across the time elapsed and heat gained by the scrap. Calculations show that this technology has the potential to save around 8 % of the energy consumption in foundries. Cumulative benefits are very encouraging: 180.45 million kWh of energy savings and 203,905 t of carbon emissions cut per year across the globe. This research reveals immense scope for this technology to be adopted by foundries throughout the world.

  15. Thermal damage of tissue during near-infrared laser irradiation with assistance of light-absorbing dye

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya C.; Le, Kelvin; Le, Henry; Wicksted, James P.; Bartels, Kenneth E.; Liu, Hong; Chen, Yichao; Chen, Wei R.

    2008-02-01

    The selective photothermal-tissue interaction using dye enhancement has been proven to be effective in minimizing the peripheral normal tissue damage during cancer treatment. It is important that the tissue-thermal damage be analyzed and the damage rate process be estimated before the photothermal-immunotherapy for cancer treatment. In this study, we have used the EMT6 mouse tumor model for the laser-tumor treatment with a simultaneous surface temperature measurement using infrared thermography. The images acquired were processed to obtain the temperature profiles. The saturation temperature and corresponding time of irradiation from the temporal profiles were used to calculate the damage parameter using Arrhenius rate process equation. The damage parameters obtained from six mice were compared. Our results of in vivo study show that the damage analyses agree with the previous in vitro study on skins.

  16. Thermal energy storage for cooling of commercial buildings

    SciTech Connect

    Akbari, H. ); Mertol, A. )

    1988-07-01

    The storage of coolness'' has been in use in limited applications for more than a half century. Recently, because of high electricity costs during utilities' peak power periods, thermal storage for cooling has become a prime target for load management strategies. Systems with cool storage shift all or part of the electricity requirement from peak to off-peak hours to take advantage of reduced demand charges and/or off-peak rates. Thermal storage technology applies equally to industrial, commercial, and residential sectors. In the industrial sector, because of the lack of economic incentives and the custom design required for each application, the penetration of this technology has been limited to a few industries. The penetration rate in the residential sector has been also very limited due to the absence of economic incentives, sizing problems, and the lack of compact packaged systems. To date, the most promising applications of these systems, therefore, appear to be for commercial cooling. In this report, the current and potential use of thermal energy storage systems for cooling commercial buildings is investigated. In addition, a general overview of the technology is presented and the applicability and cost-effectiveness of this technology for developed and developing countries are discussed. 28 refs., 12 figs., 1 tab.

  17. Thermal energy storage for a space solar dynamic power system

    NASA Technical Reports Server (NTRS)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.

    1985-01-01

    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  18. Thermal energy storage for the Stirling engine powered automobile

    NASA Technical Reports Server (NTRS)

    Morgan, D. T. (Editor)

    1979-01-01

    A thermal energy storage (TES) system developed for use with the Stirling engine as an automotive power system has gravimetric and volumetric storage densities which are competitive with electric battery storage systems, meets all operational requirements for a practical vehicle, and can be packaged in compact sized automobiles with minimum impact on passenger and freight volume. The TES/Stirling system is the only storage approach for direct use of combustion heat from fuel sources not suitable for direct transport and use on the vehicle. The particular concept described is also useful for a dual mode TES/liquid fuel system in which the TES (recharged from an external energy source) is used for short duration trips (approximately 10 miles or less) and liquid fuel carried on board the vehicle used for long duration trips. The dual mode approach offers the potential of 50 percent savings in the consumption of premium liquid fuels for automotive propulsion in the United States.

  19. Molten salt thermal energy storage for utility peaking loads

    NASA Technical Reports Server (NTRS)

    Ferrara, A.; Haslett, R.; Joyce, J.

    1977-01-01

    This paper considers the use of thermal energy storage (TES) in molten salts to increase the capacity of power plants. Five existing fossil and nuclear electric utility plants were selected as representative of current technology. A review of system load diagrams indicated that TES to meet loads over 95% of peak was a reasonable goal. Alternate TES heat exchanger locations were evaluated, showing that the stored energy should be used either for feedwater heating or to generate steam for an auxiliary power cycle. Specific salts for each concept are recommended. Design layouts were prepared for one plant, and it was shown that a TES tube/shell heat exchanger system could provide about 7% peaking capability at lower cost than adding steam generation capacity. Promising alternate heat exchanger concepts were also identified.

  20. Preliminary considerations for extraction of thermal energy from magma

    SciTech Connect

    Hickox, C.E.; Dunn, J.C.

    1985-01-01

    Simplified mathematical models are developed to describe the extraction of thermal energy from magma based on the concept of a counterflow heat exchanger inserted into the magma body. Analytical solutions are used to investigate influence of the basic variables on electric power production. Calculations confirm that the proper heat exchanger flow path is down the annulus with hot fluid returning to the surface through the central core. The core must be insulated from the annulus to achieve acceptable wellhead temperatures, but this insulation thickness can be quite small. The insulation is effective in maintaining the colder annular flow below expected formation temperatures so that a net heat gain from the formation above a magma body is predicted. The analyses show that optimum flow rates exist that maximize electric power production. These optimum flow rates are functions of the heat transfer coefficients that describe magma energy extraction. 15 refs., 3 figs.