Showing papers on "Thermal energy published in 1997"

Energy Input and Mass Redistribution by Supernovae in the Interstellar Medium

Abstract: We present the results of numerical studies of supernova remnant evolution and their effects on galactic and globular cluster evolution. We show that parameters such as the density and the metallicity of the environment significantly influence the evolution of the remnant, and thus change its effects on the global environment (e.g., globular clusters, galaxies) as a source of thermal and kinetic energy. We conducted our studies using a one-dimensional hydrodynamics code, in which we implemented a metallicity dependent cooling function. Global time-dependent quantities such as the total kinetic and thermal energies and the radial extent are calculated for a grid of parameter sets. The quantities calculated are the total energy, the kinetic energy, the thermal energy, the radial extent, and the mass. We distinguished between the hot, rarefied bubble and the cold, dense shell, as those two phases are distinct in their roles in a gas-stellar system. We also present power-law fits to those quantities as a function of environmental parameters after the extensive cooling has ceased. The power-law fits enable simple incorporation of improved supernova energy input and matter redistribution (including the effect of the local conditions) in galactic/globular cluster models. Our results for the energetics of supernova remnants in the late stages of their expansion give total energies ranging from 9e49 to 3e50 ergs, with a typical case being 1e50 erg, depending on the surrounding environment. About 8.5e49 erg of this energy can be found in the form of kinetic energy. Supernovae play an important role in the evolution of the interstellar medium

Hydrologic cells for recovery of hydrocarbons or thermal energy from coal, oil-shale, tar-sands and oil-bearing formations

Abstract: A system for recovery of hydrocarbons or thermal energy from host-rock fotions bearing coal, oil-shale, tar-sands or oil by use of a hydrologic cell which conveys a reacting fluid under pressure to a source-aquifer, thereafter extracting thermal energy or hydrocarbons from said host-rock, moving said hydrocarbons or thermal energy to said sink-aquifer and then removing the hydrocarbons or thermal energy to the surface for ultimate use.

Rechargeable thermal battery for latent energy storage and transfer

Abstract: A thermal energy storage and transfer device (80) that includes a thermal reservoir (88) maintained about its freezing or melting point temperature for storing a quantity of latent thermal energy, a thermal conductor (86) between the reservoir (88) and an external substance (82) and a means (84) for recharging the reservoir.

Molecular-dynamics simulation of evaporation of a liquid

Abstract: The molecular-dynamics method is used to investigate high-temperature evaporation of a simple liquid. The interaction of the atoms is described by a Lenard-Jones 6–12 potential. The simulation shows that fluctuations of the binding energy in the surface layer play an important role in evaporation, thanks to which a significant contribution to the evaporated flux comes from atoms whose kinetic energy is of the same order of magnitude as the mean thermal energy. Such a mechanism of evaporation differs substantially from the traditional one [Ya. I. Frenkel’, Kinetic Theory of Liquids (Clarendon Press, Oxford, 1946)] based on the assumption that only those particles evaporate that have energies of the order of the binding energy, i.e., much larger than the mean thermal energy. The structure of the transitional layer between the bulk gas and liquid phases is investigated. Potential energy fluctuations and pairwise correlation functions in the bulk phases and transitional layer are calculated. The velocity distribution function of the atoms for evaporation into vacuum is found.

Numerical simulation of ultra-short laser pulse energy deposition and transport for material processing

Abstract: We have extended the physics of the one-dimensional radiation hydrodynamics simulation code HYADES to include processes important for studying laser-matter interaction with dielectrics and metals in the eV and sub-eV electron . temperature range. Ultra-short laser pulses USLP are advantageous in many material processing situations where most of the absorbed laser energy appears in mass motion, and little appears as thermal energy. Major additions to the code include . . 1 the transport, reflection and absorption of laser light, 2 thermal energy transport and improved shockwave physics, and . . 3 improved models for the equation of state EOS , strength of materials, and fracture. Examples from material processing and plasma generation were chosen for simulation. Our numerical simulations include the effects of radiation transport, hydrodynamic expansion and shockwave phenomena. q 1998 Elsevier Science B.V.

Energy conversion composition

Abstract: An energy conversion composition having the functions of absorbing and converting energy, such as mechanical energy, thermal energy, optical energy or electric energy, having an excellent performance and capable of reducing the thickness and volume of the composition. This energy conversion composition is characterized in that a base material thereof contains an active component which increases the level of dipole moment in the base material. This energy conversion composition can be used as, for example, a damping material, a sound absorption material, an impact absorption material, a vibration proofing material, an electromagnetic wave absorption material, a piezoelectric material, a heat absorption material, or a polar liquid material.

Piezo-pyroelectric energy converter and method

Abstract: The present invention embodies a piezo-pyroelectric energy converter and is directed to a method and apparatus for conversion of thermal energy to electrical energy and refrigeration. The present invention utilizes one or more piezo-pyroelectric materials with thermally conductive metal electrodes, which resonate at a high frequency and are in thermal communication with hot and cold heat sinks to create a thermal gradient and heat flow along the metal electrodes and the piezo-pyroelectric material.

CRC handbook of energy efficiency

Abstract: General Principles U.S. Energy System, F. Kreith and R. West Fundamentals of Thermodynamics, Heat Transfer, and Fluid Mechanics, V. Hassani and S. Hauser Economic Methods, R.T. Ruegg Electric-Utility Integrated Resource Planning: Current Practices and Future Possibilities, E. Hirst Introduction to Social Externality Costs, J. Koomey and F. Krause Generation Technologies Through Year 2005, A.F. Armor The Outlook for U.S. Energy Supply, Demand, and Prices through 2010, A.S. Kydes, S. Sitzer, and L.K. Bonadies The Changing Structure of Electric Markets: Implications for Public Policy, L. Hill Energy Conservation Thermal Conservation in Buildings, M. Sherman and D. Jump Electrical Energy Management in Buildings, C.B. Smith Heating, Ventilating, and Air Conditioning Control Systems, J.F. Kreider Energy Efficient Technologies: Electric Motors, A.T. de Alimeida and S. Greenberg Energy Efficient Lighting Technologies and Their Applications in the Commercial and Residential Sectors, B. Atkinson, A. Denver, J.E. McMahon, L. Shown, and R. Clear Appliances, Heat Pumps, and Air Conditioning, J.E. McMahon, I. Turiel, G. Rosenquist, J. Lutz, S. Boghosian, and L. Shown Recuperators, Regenerators, and Storage Recuperators, Regenerators, and Compact Heat Exchangers, R.K. Shah Thermal Energy Storage Applications in Gas-Fired Power Plants, D.R. Brown and S. Somasundarian Thermal Energy Management in Industry, W. Rohrer Process Energy Efficiency: Pinch Technology, K. Trivedi Electrical Power Management in Industry, C.B. Smith Co-Generation, J. Caton and D. Turner Renewable Energy Availability of Renewable Resources Solar Radiation, D.S. Renne, E.L. Maxwell, M.D. Rymes, W. Marion, and J. Phillips Wind Energy, D. Elliott, M. Schwartz, B. Bailey, and J. Phillips Biomass Energy, M.A. Franklin and F. Kreith Active Solar Heating Systems, T.A. Reddy Passive Solar Heating, Cooling, and Daylighting, J. Morehouse Solar Thermal Power and Industrial Heat Solar Thermal Power, L.L. Vant-Hull Parabolic Trough Concentrating Collectors and Component System Design, R.C. Gee and E.K. May Photovoltaic Solar Energy, J. Krenz Wind Power, D. Eggleston Waste-to-Energy Combustion, C.O. Velzy and R. Hecklinger Index

Thermal model for central processing unit

Abstract: A technique for implementing a programmable thermal model of an integrated circuit component such as a central processing unit (CPU) and its associated heat sink. The model estimates the die temperature of the component as if there were no cooling devices present in the system such as a forced air cooling fan by integrating the thermal energy added when the component is active and by integrating the thermal energy removed when it is idle. A programmable power value may be used to represent the heat added to the model at each model sample period. The effect of a heat sink in cooling the idle component may be modeled by reducing the value of the heat accumulator by a predetermined fractional amount during each sample period. The decay time constant for the model may be changed by then adjusting the sample period. With an accurate model estimate predicting the component temperature in the absence of cooling being instantaneously available, any associated cooling device such as a fan can be operated in such a manner as to turn on only when it is estimated to actually be needed and to be kept off at all other times. In addition, a turn off delay can be implemented in order to avoid undesirable cycling effects.

Micro impact drive mechanisms using optically excited thermal expansion

Abstract: The physical phenomenon of thermal expansion of solid materials is useful for microdisplacement actuators because of the scale effect. The response speed of thermally excited actuators is directly coupled with the thermal emission speed, and its value is quite low for mechanisms of the macroscale. However, this speed becomes considerably higher as the actuator becomes smaller. Various methods exist to supply thermal energy to the actuator in order to accomplish thermal expansion. Among them, thermal expansion by means of optical excitation proves to be a good candidate. Major advantages of optical excitation is that it enables noncontact thermal energy supply and remote operation in a special environment such as vacuum and at high environmental temperatures. The structure of the microactuator is simple, and it can be made from various materials using easy fabrication processes. Supported by these advantages, thermally driven micro impact drive mechanisms were developed and fabricated. The global size of the realized micromechanisms is approximately 1.7/spl times/0.6/spl times/0.4 mm/sup 3/. All are made of aluminum alloy by precision-cutting techniques, which is suitable for the fabrication of three-dimensional (3-D) shapes. The maximum travel speed and minimum displacement of the developed mechanisms are about 30 mm/s and 1 /spl mu/m, respectively.

Method and apparatus for producing superheated steam using heat from the incineration of waste material

Abstract: According to the present invention, boiler water is pressurized so that its boiling point is set at approximately 200° C. to 320° C. The boiler water is heated in at least two stages. Thermal energy of gases containing chlorine compounds is used to heat the water to its boiling point. Thermal energy of gases which do not contain chlorine compounds is used to heat the water from its boiling point until superheated steam of a given temperature is generated. The heating which uses the thermal energy of gases containing chlorine compounds is accomplished using the thermal energy from the combustion of pyrolysis gases obtained from a pyrolysis means in which waste material is supplied into a chamber containing a fluidized bed medium which has been heated to at least 300° C., and a pyrolytic reaction is induced. The heating which uses the thermal energy of gases which do not contain chlorine compounds is accomplished using the thermal energy obtained from a char combustion means to combust char in which a char mixture consisting of unpyrolyzed residue and fluidized bed medium removed from the pyrolysis means is fluidized by a stream of air, and the unpyrolyzed residue is combusted.

Correlation Energy, Thermal Energy, and Entropy Effects in Stabilizing Different Secondary Structures of Peptides

Abstract: Quantum chemical calculations on some typical elements of secondary structure in peptides and proteins (β sheets, β and γ turns) at the Hartree−Fock and MP2 correlation energy levels show considerable differences in the stability orders of alternative structures. The correlation energy data indicate an overestimation of hydrogen-bonded structures. Thus, correlation energy data may be misleading when comparing peptide structures of different type, as for instance, conformations with and without hydrogen bonds or with a different number of hydrogen bonds. This effect is corrected at the Gibbs free energy level when including thermal energy and entropy contributions. Considerable compensation of correlation energy and entropy contributions is mainly responsible for the relatively good correspondence of Hartree−Fock energy differences obtained with more extended basis sets and the free enthalpy data at the correlation energy level.

Article for thermal energy storage

Abstract: 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.

Determining when to discontinue auxiliary heating of catalyst from cold start

Abstract: The criterion indicating achievement of initiation- or light-off temperature for catalytic action, is the time integral of thermal energy supplied by exhaust gases to the catalyst (4). Additional heating is shut off, once energy supplied exceeds a given threshold (SW1). Preferred Features: Thermal energy supplied is determined from: exhaust gas mass flowrate, its specific heat at constant pressure and the exhaust temperature upstream of the catalyst. Exhaust mass flowrate is determined from the inlet air mass flowrate induced directly by the engine, and from the secondary air mass flowrate. The latter is introduced by the secondary air injection system (8, 9, 16). A correction included, takes into account the quantity of fuel introduced. The calculated total energy supplied to the catalyst is corrected for convective heat losses, taking into account vehicle speed. For this purpose, corrections in terms of speed are stored in e.g. a look-up table in computer memory. A sensor (11) measures exhaust temperature. Alternatively its temperature is deduced from stored data, in terms of measured stoichiometry, air inlet flowrate, and ignition timing. In a similar method, the temperature reached by the catalyst is deduced from its measured inlet and outlet temperatures, to indicate when additional heating can be discontinued. A further related method is based on direct measurement of the catalyst substrate temperature. For each of the foregoing methods, the mathematical relationships are set out.

LNG Receiving Terminal Associated With Gas Cycle Power Plants

Abstract: LNG regasification process needs a considerable quantity of thermal energy that is usually obtained by cooling sea water or by burning a fraction of the evaporated natural gas. These systems, though offering low cost and high reliability, are thermodynamically inefficient: they require energy for water pumping or fuel to provide heat and do not exploit the physical exergy related to the initial conditions of LNG to produce mechanical work.The present paper aims to assess the performances of various gas turbine based cycles which use the LNG regasification process as a low temperature heat sink for power cycles. In particular it will focus on the following configurations:• Closed loop gas cycles• Gas-gas combined cycles• Combined gas-organic Rankine cyclesTwo different sendout pressure (70 and 30 bar, corresponding respectively to the supply of long-distance pipelines or power plants based on heavy-duty gas turbines) are considered. Their performances are calculated and proper effectiveness indexes (e.g. thermal and exergetic efficiency) are introduced to carry out a comprehensive comparison among the systems considered. A simple economical analysis completes the discussion.Copyright © 1997 by ASME

Non-thermal energy treatment for the reduction of microbial population in liquid food products

Abstract: Conventional food treatment processes utilized for food preservation generally involve heat treatment and usually result in some degree of thermal damage. A process has been developed for the non-thermal treatment of liquid food products which results in a significant reduction in the microbial population, thus reducing spoilage and extending shelf life. The novel process involves the rapid application of electromagnetic energy (EME), such as microwave or radio frequency energy, and the simultaneous removal of any thermal energy which may be generated by the process through the use of circulating cooling medium and an efficient heat exchanger.

Rice processing in india: a generalized framework for energy demand estimation

Abstract: A generalized framework for the estimation of primary energy demand for parboiling and milling of paddy in India has been proposed. The dependence of both the electrical and thermal energy components of the demand on different methods of parboiling and technologies for milling have been considered. The possible uncertainties in the above estimation have also been identified. A few numerical calculations have been made for some typical technology/product mix scenarios. © 1997 by John Wiley & Sons, Ltd.

Heat reflector for use with fireplace grate for high temperature combustion

Abstract: A low thermal mass heat reflector for use with a fireplace grate which has a combustion zone directly thereabove when fuel is burned thereon in a fireplace. The heat reflector comprises a first portion for absorbing radiant energy from the combustion zone and reradiating thermal energy back into the combustion zone, and a second portion for absorbing radiant energy from the combustion zone and reradiating thermal energy over the fireplace grate and out of the fireplace.

Process and plant for operating a block-type thermal power station

Abstract: Block-type thermal power stations generate demand-dependent useful energy, in particular current as electric energy and/or heat or cold as thermal energy. A prospective calculation of the current and heat demand for at least the next 24h is calculated based on different presently available criteria, and the consumption integrals that may be derived therefrom are determined and evaluated. The operation of the plant, preferably in the high tariff phase, is derived therefrom with optimum evaluation of the incoming and outgoing energies. The corresponding plant contains a processor unit in an automating machine, which may in particular be a processor unit already available in the plant for which an appropriate software is created. An energy optimisation program for block-type thermal power stations is thus set up with the available data.