Showing papers on "Thermal energy published in 1976"

Nonadiabatic Processes in Molecular Collisions

Abstract: Substantial effort has been directed toward developing methods for describing molecular collision processes that are electronically adiabatic, i.e., for which it can be assumed that nuclear motion evolves on a single potential energy hypersurface. A number of recent reviews are devoted to this subject.(1–8) Considerably less attention has been paid to processes that are nonadiabatic,i.e., that involve electronic transitions between potential energy surfaces. This is in spite of the fact that nonadiabatic behavior is both common and important, even in thermal energy collisions.

Thermal energy storage by means of reversible heat pumping

Abstract: A method is described for storing the offpeak electrical output of an electricity generating plant in the form of heat by using it to raise the temperature level of a quantity of stored heat retention material and recalling said stored heat during periods of peak power demand in the form of electrical power During low power demand periods hot water is drawn from a hot water storage means and cooled by flashing it at successively lower pressures The cold condensate is sent to a cold water storage means while the various flash vapors are fed to appropriate stages of a steam compressor driven by excess power drawn from the electricity generating station The steam which has been compressed by means of the excess electrical power is directed to heat exchanger means where it is used to heat a low vapor pressure (LVP) thermal energy retention material flowing from cold to hot storage means through the heat exchanger means By the practice of this invention, heat is transferred, by means of the steam compressor powered by excess electrical power, from hot water (˜ 210° F) to the LVP material raising its temperature from a cold storage temperature of about 190°-300° F to a hot storage temperature of about 450°-600° F The hot LVP material is stored at atmospheric pressure preferably under an inert gas atmosphere During peak energy demand periods, the process is reversed and the hot LVP material is used to generate steam which runs a turbine thereby producing electrical power from a generator

High Temperature Microwave Heating in Refractory Materials

Abstract: Microwave energy can be used to create high temperatures (> 1700° C for alumina) in refractory materials. Energy conversion takes place with a very good efficiency (90% in the conversion process of microwaves to thermal energy) if an appropriate applicator is utilized.Experiments at 2.45 GHz involving either the sintering of alumina or melting of silica for fiber fabrication are described which confirm the feasibility of this new process.

Thermal energy storage systems employing metal hydrides

Abstract: Thermal energy storage systems employing metal hydrides are useful for storing thermal energy produced, for example, by solar radiation. The metal hydrides, examples of which include FeTiH and the VH-VH 2 reaction system, evidence ease of reversibility of the metal-hydrogen reaction and have relatively high heats of formation. An additional advantage of the metal hydrides over other thermal storage materials is that the metal hydrides permit a greater degree of control to be exercised over the rate of heat evolution when needed.

On the kinetic energy of the divergent and nondivergent flow in the atmosphere

Abstract: The kinetic energy of horizontal flow in a hydrostatic atmosphere is divided into the kinetic energies of its divergent and nondivergent components. The law of conversion between these two energies for large-scale flows in the atmosphere is derived and discussed using balanced and unbalanced models of circulations in the atmosphere. It is shown that the total potential energy is converted into the kinetic energy of the divergent flow which, in turn, is converted into the kinetic energy of the nondivergent flow. These energy conversions are equal in a so-called balanced model, but may differ in a model based on the primitive equations. The analysis shows that the kinetic energy reservoir of the divergent part of the flow may play a quasi-catalytic role in the energy conversion between the total potential energy and the kinetic energy of the nondivergent flow. Two sets of data, the history data generated by the NCAR GCM of a January simulation, and the NMC wind data and FNWC height field of August 1 to 15 of 1970, were used to evaluate the energies and energy conversions. The computations confirm the direction of energy conversions in the theoretical argument and the quasi-catalytic nature of the kinetic energy of the divergent part of the flow. The energy conversions between the total potential energy and the kinetic energy of the divergent flow occurs mainly in the lower layers of the atmosphere at middle latitudes where the baroclinic eddy activities are dominant. The energy conversion between the kinetic energies of the divergent and the nondivergent flows is mostly carried out by the Coriolis effect. In other words, the quasi-geostrophic model explains most of this energy conversion. The introduction of a more sophisticated model gives small improvement as far as the magnitude of energy is concerned. DOI: 10.1111/j.2153-3490.1976.tb00697.x

Method and apparatus for generating steam

Abstract: A method and apparatus for generating steam including an internal combustion engine providing mechanical energy and also thermal energy which is commonly referred to as waste heat. In one aspect, the engine drives a heat pump, and the low temperature side of the heat pump removes waste heat from the engine and in some instances also heat from the environment, while the high temperature side of the heat pump delivers heat to an unfired steam boiler. In another aspect, the engine drives a water injectable compressor, and waste heat from the engine is utilized in a heat exchanger to boil water and thereby produce steam at a relatively low temperature and pressure. This steam enters the compressor and emerges therefrom at a relatively high temperature and pressure. In all aspects, the generated steam can be used for such applications as heating or the operation of a steam engine.

Process and apparatus for heat exchange

Abstract: A process and apparatus is provided for storing thermal energy and subsequently releasing and extracting the stored thermal energy upon demand. At least one sealed container of salt hydrate is agitated continually and is positioned in heat exchange relationship with a heat exchange liquid which is passed between a thermal energy source and a container enclosing or partially enclosing the sealed container(s) for the salt hydrate. Agitation of the container(s) of salt hydrate prevents or minimizes salt separation and supercooling so that the latent heat of fusion of the salt hydrate can be stored and extracted by the heat exchange liquid upon demand, in addition to the sensible heat of the salt hydrate composition.

Hydride heat pump

Abstract: Method and apparatus for the use of hydrides to exhaust heat from one temperature source and deliver the thermal energy extracted for use at a higher temperature, thereby acting as a heat pump. For this purpose there are employed a pair of hydridable metal compounds having different characteristics working together in a closed pressure system employing a high temperature source to upgrade the heat supplied from a low temperature source.

Gravity head geothermal energy conversion system

Abstract: A geothermal energy recovery system of improved life duration makes use of thermal energy stored in hot, solute-bearing well water as it is pumped upward to the earth's surface through an extended heat exchange element for continuously heating a downward flowing organic working fluid to a supercritical state. Some of the energy of the latter fluid is used within the well for operating a turbine-driven pump for pumping the hot well water at high pressure and always in liquid state to the earth's surface, where it is reinjected into the earth in a second well. After driving the deep-well turbine-driven pump, the organic fluid still in supercritical state arises toward the earth's surface in a thermally insulated conduit; at the earth's surface, vapor turbine electrical power generation equipment is driven by the ascending organic fluid, after which it is returned into the well for re-heating in the extended heat exchanger. The invention provides a long life, closed-loop fluid lubricant pumping and cooling system for the bearings of the turbine and brine pump system, normally isolated from the working fluid loop and the hot brine pumping and heat exchange loop. Should the pressure level within the lubricant loop fall below a predetermined level, auxiliary means are provided for coupling working fluid into the lubrication loop to maintain the pressure within the loop above that of the hot brine, thus excluding intrusion of the corrosive brine.

Solar energy collectors

Abstract: This invention utilizes a solar radiation absorbing fluid (i.e., a black fluid) for direct solar energy to thermal energy transfer. The unique structure of the several disclosed embodiments of this invention provides for a selected distribution and a selected depth of the absorbing fluid in the solar energy exposed area. The disclosed apparatus converts solar radiation energy into thermal energy with higher conversion efficiency, lower material and manufacturing costs and considerable weight reduction compared to conventional solar collectors.

Electrical and thermal energy supply system for buildings

Abstract: An electrical and thermal energy supply system for buildings is disclosed wherein electricity is generated by an engine driving a generator either inside or in close proximity to the building. Heat generated by the engine is recovered and supplied to the building. The electrical generating system is activated on demand for electricity from within the building. Optionally, the output of the generator may be used to electrically heat water or air, or both, to supplement the heat recovered from the operation of the engine. Additionally, a battery-inverter, chargeable by the generator, may be included to reduce the duty cycle of the engine. A wind powered generator may be further added to charge the battery and conserve fuel, especially in warmer time periods.

Hydraulic prime mover device

Abstract: The invention described herein is a new and novel prime mover device which operates as in integral component of a heat vapor cycle which, in combination, represents a heat engine system consisting of a closed, vertically oriented fluid recirculation system, utilizing a non-compressible fluid as a working medium. Wherein the device's fluid downward flowing section comprises a fluid penstock and a hydraulic turbine, whose function is the conversion of the downward flowing fluid's potential energy into kinetical energy and then into mechanical energy by driving the turbine which, in turn, drives the electrical generator. Whereas the device's upward flowing section serves the function of lifting the turbine exhausted fluid back to its initial potential, which is accomplished by the heating of the turbine exhausted fluid and its maintenance at operating temperature, in combination with induction of a cooled, condensed gas into the heated fluid at the device's lowermost effective portion which, by virtue of its heat absorption from the fluid, as well as its evaporation and subsequent expansion therein, displaces an equivalent amount of fluid within the device's vertical riser, thus giving rise to the lowering of the fluid's specific gravity within the device's upward flowing section, in contrast to the fluid's specific gravity within its downward flowing section. This causes the fluid to circulate as long as a steady supply of thermal energy, as well as a steady flow of cooled gas, is available. The gas, upon heating and expansion, is separated from the fluid, then cooled and condensed to initial state.

Geothermal energy processing system with improved heat rejection

Abstract: The improved geothermal energy extraction system abstracts thermal energy stored in hot solute-bearing well water to generate a super-heated fluid from an injected flow of a working fluid; the super-heated fluid is then used to operate a turbine-driven pump at the well bottom for pumping the hot geothermal brine in liquid state toward the earth's surface. After energy for the generation of electrical power is extracted from the brine, a consequently cooled portion of the brine is then used at the earth's surface in a combination unitary cooling tower and working organic fluid condensing system. The invention combines the cooling tower and condenser functions in an integrated unit, the outer surfaces of the condenser tubes being exposed to a cascading flow of cooling brine while the brine is itself being cooled. The condenser tubes are arranged geometrically so that a cleaning device may continuously or upon command travel along the condenser tubes, cleaning their outer surfaces of scale accumulations deposited by the depressurized brine.

Extension of the Hottel-Whillier-Bliss model to the analysis of combined photovoltaic/thermal flat plate collectors

Abstract: Abstract The well known Hottel-Whillier model for thermal analysis of flat plate collectors is extended to the analysis of combined photovoltaic/thermal collectors in a manner, such that, with simple modification of the conventional parameters of the original model, all of the existing relations and supporting information available in the literature still apply. Beyond the basic assumptions of the original model, it is only necessary to assume that the local electrical conversion efficiency of the solar cell array (absorber) is a linear decreasing function of the local absorber temperature over its operating temperature range. Based on the extended model, examples of both thermal and electrical performance of a combined collector as a function of collector design parameters are presented and discussed.

Thermal energy production by in situ combustion of coal

Abstract: This specification discloses a method of recovering thermal energy from a coal formation having a preferred vertical fracture orientation. An injection well and a production well are provided to extend into the coal formation and a vertical fracture is formed by hydraulic fracturing techniques and propagated into the coal formation to communicate with both the wells. The vertical fracture is propped in the lower portion only. A combustion-supporting gas is injected into the propped portion of the fracture and the coal is ignited. Injection of the combustion-supporting gas is continued to propagate a combustion zone along the propped portion of the fracture and hot product gases generated at the combustion zone are produced to recover the heat or thermal energy of the coal. Water may also be injected into the fracture to transport the heat resulting from the combustion of the coal to the production well for recovery.

System for storing and releasing thermal energy

Abstract: A system for the cyclic storage and recovery of thermal energy utilizing a particulate bed of a decomposable heat storage material selected from the group consisting of the hydroxides of magnesium, calcium, and barium. The bed of heat storage material is confined within a container adjacent a water-permeable wall of the container. Thermal energy of chemical decomposition is stored by heating the bed of selected hydroxide to a temperature within the range of from 300° C to 900° C and above the decomposition temperature of the selected hydroxide for a time sufficient to decompose at least a part of the selected hydroxide to form the corresponding oxide and water vapor. The water vapor is withdrawn by passing a carrier gas into contact with the water-permeable wall of the container to absorb the water vapor permeating therethrough. The stored thermal energy is recovered by passing a water-laden carrier gas into contact with the water-permeable wall, whereby the water vapor permeates through the wall into contact with the oxide to reform the selected hydroxide and generate heat of reaction which is removed by the carrier gas.

Characteristics of a water absorber in front of a silicon solar cell

Abstract: In a system for converting sunlight to both electric power and heat, a selective absorber between the sun and a semiconductor solar cell may provide a substantial thermal output without seriously reducing the electrical output. Calculations for water in front of a typical silicon solar cell show, for example, that a water layer 1 cm thick absorbs 16.3% of the incident energy (chiefly photons having energies below the energy gap of silicon) while reducing the electric power output only slightly, from 13.8 to 13.1%. Experimental results confirm this finding.

Modular heat recuperator

Abstract: A heat recuperator for recovering thermal energy from exhaust gases emitted by a high temperature combustion furnace. The thermal energy is absorbed by an incoming stream of air. The heated air may be diverted to auxiliary heat-requiring systems and/or mixed with fuel and used in the combustion process thereby providing significant savings in energy consumption. The heat recuperator is constructed as a countercurrent-flow heat exchanger, preferentially, from a plurality of interchangeable modular elements. Each modular element is longitudinally separated into at least two flow channels in heat exchange relationship. One flow channel is used for hot exhaust gases while the incoming air is forced countercurrently through another flow channel to thereby absorb thermal energy from the hot exhaust gases. Modular construction readily accommodates (1) assembly of various size heat recuperators from standardized modular elements, (2) replacement of damaged modular elements without replacing the entire heat recuperator, (3) ease of (a) handling, (b) disassembly, and (c) cleaning and (4) selectively fabricating different modular elements from different materials of construction to specifically meet and withstand the different environmental conditions to be encountered by the various parts of the heat recuperator so constructed.

Demand sensitive energy storage in molten salts

Abstract: Heat-of-fusion energy storage and on-demand steam are obtained using heat pipe techniques to transfer heat to and from stacked salt cans and onto boiler tubes within a sealed “energy storage-boiler” tank.

Thermal energy method and machine

Abstract: This is a method and an apparatus for performing said method, for the conversion of thermal energy into mechanical or electrical energy by means of an exchange of temperature between two water sources having a temperature differential, and utilizing a compressible fluid to be alternately compressed and expanded by the use of the thermal differential, with the flow imparted to the compressible fluid utilized through an improved positive displacement rotary valve and a motor wherein the motor is operated by hydraulic cylinders alternately pressurized and depressurized and connected between a pair of canted discs.

Systems for making use of the energy carried by a fluid and supplied thereto by solar energy

Abstract: A system for making use of the thermal energy carried by a fluid and which is supplied to the fluid by a solar energy detector which converts the solar energy into heat. The system basically comprises a solar energy detector which heats the fluid and valves, operated by the intrinsic energy of the fluid, for enabling the fluid to discontinuously flow through the detector only in a single direction. In one embodiment the system is used to pump hot air into a space to be heated. In other embodiments pressure accumulating chambers are also provided to accumulate the energy of the fluid which is intermittently supplied to a heat exchanger. The pressure accumulating chamber in another embodiment is an arrangement for producing work, such as a water pump or the compressor of a refrigerating system.

Survey of high temperature thermal energy storage

Abstract: A survey of current technology relating to high temperature thermal energy storage is presented. The motivation for this study resulted from the need for energy storage in solar thermal applications; however, the results have much wider application. The generic classes of storage concepts considered are sensible heat, latent heat, and heat of reversible chemical reaction. The study includes a review of the basic thermodynamic aspects of thermal energy storage; a summary of storage concepts which have been conceptualized and/or built and tested, including comparisons of system characteristics within the generic classes; and, finally, specific technology surveys within the areas of materials problems, heat transfer and fluid mechanics problems and systems application. It is shown that the design and engineering of thermal storage systems have not progressed beyond the most simple concepts and that there has been only a limited effort in the design and construction of large scale systems. Current technology appears adequate to support the development of most sensible heat concepts and simple latent heat concepts while some degree of technology advancement will be required to develop advanced latent heat concepts and heat-of-reaction concepts. Specific recommendations for future research and development work are presented.

Turbine system method and apparatus

Abstract: A method and apparatus for operating a gas turbine system are disclosed utilizing an adiabatic combustion process, employing combustion of a pre-mixed carbonaceous fuel-air admixture in a combustion zone. The combustion and the combustion zone are maintained at an approximately constant temperature by selective control of the fuel-to-air ratio over a period of turbine operation during which the fuel demand or the combustion air temperature varies. Such control of the combustion zone temperature is such that said constant temperature is substantially above the instantaneous auto-ignition temperature of the fuel-air admixture. The resulting effluent is characterized by high thermal energy useful for generating power and may be low in atmospheric pollutants, including oxides of nitrogen.