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Showing papers on "Thermal energy published in 1979"


Journal ArticleDOI
TL;DR: In this paper, the ideal gain and maximum energy conversion rates were derived for differentially heated regenerators and the low power gain measurements were made to verify the derived gain equation and practical engines and heat pumps using this principle.
Abstract: The propagation of acoustical waves through a differentially heated regenerator results in gas in the regenerator undergoing a Stirling thermodynamic cycle. One direction of wave propagation results in amplification of the waves and conversion of thermal energy into acoustical energy. The opposite direction results in acoustical energy being used to pump heat. The ideal gain and maximum energy conversion rates are derived in this paper. Low power gain measurements were made which verify the derived gain equation. Practical engines and heat pumps using this principle are discussed.

414 citations


Journal ArticleDOI
TL;DR: In this article, a general design method is presented for closed loop energy systems consisting of solar collectors, sensible energy storage and a closed-loop flow circuit in which thermal energy is supplied (through heat exchange) to a load above a specified minimum temperature.

133 citations


Patent
02 Apr 1979
TL;DR: In this article, the plane structute of a heating element is formed to be a trapezoid and at both ends thereof electrodes 302 and 303 are provided, where the current density at the part A and part B is changed, a difference can be made in the quantity of the heat per unit time in each part.
Abstract: PURPOSE: To enable the gradation recording by getting the heating element of an electrothermal transducer constructed so that it can produce a heat gradient in an ink jet head wherein the change in pressure by thermal energy is utilized. CONSTITUTION: The plane structute of a heating element 301 is formed to be a trapezoid and at both ends thereof electrodes 302 and 303 are provided. When the current density at the part A and part B is changed, a difference can be made in the quantity of the heat per unit time in each part. In addition, by proividing a heat-accumulating layer 403 and a protecting film 406 having a grade in thickness from an electrode 404 toward an electrode 405 on a substrate 401 as shown in the figure of a cross-sectional structure, the grade is also given to the quantity of the heat applied by the surface of a heating element Δl to the liquid contacting with the surface per a unit time. By this gradient in the quantity of the heat, the quantity of air bubbles formed on the contacting surface of the heating element is changed and thereby the quantity of discharged ink can also be changed. COPYRIGHT: (C)1980,JPO&Japio

127 citations


Journal ArticleDOI
TL;DR: In this paper, the anomalous transport of electron thermal energy in existing experiments on magnetically confined toroidal plasmas is discussed and a new form of the relevant electron thermal conductivity, that is consistent with the observed temperature profiles, is presented.

72 citations


Patent
16 May 1979
TL;DR: In this paper, flat plate reflectors are pivoted to move with the position of the sun and concentrate additional energy on a solar energy collector panel for tracking the sun over its seasonal variations by means of simple mechanisms pivoting the reflector plates.
Abstract: Simple flat plate reflectors, preferably compound of a panel with a reflector surface layer laminated thereto, are pivoted to move with the position of the sun and concentrate additional energy on a solar energy collector panel. The array can take a tented or triangular end view shape for closing to protect reflective surfaces from hail or sandstorm, etc. Also the surfaces are provided with a periodically operable surface cleaner to assure long term efficiency even when remotely positioned as on roof top. Low cost present day computers are programmed to track the sun over its seasonal variations by means of simple mechanisms pivoting the reflector plates. The system is self-energizing by means of batteries charged by solar panels accompanying the system. Solar energy is storable in a self-contained water tank for use at night, etc. and efficient energy conversion is attained by means of a stainless steel pipe length extending into the stored water and thermally coupled outside the tank to a solar heated higher than 100° C. silicon oil circulated through the solar collector. Thus, vaporization is avoided and an effective low-cost simplified thermal energy conversion is effected.

57 citations


Journal ArticleDOI
TL;DR: In this paper, an experiment was performed by Auburn University in which 54,784 m3 of water was pumped from a shallow supply aquifer, heated to an average temperature of 55°C, and injected into a deeper confined aquifer where the ambient temperature was 20°C.
Abstract: To aid in testing the idea of storing thermal energy in aquifers, an experiment was performed by Auburn University in which 54,784 m3 of water was pumped from a shallow supply aquifer, heated to an average temperature of 55°C, and injected into a deeper confined aquifer where the ambient temperature was 20°C. After a storage period of 51 days, 55,345 m3 of water were produced from the confined aquifer. Throughout the experiment, which lasted approximately 6 months, groundwater temperatures were recorded at six depths in each of 10 observation wells, and hydraulic heads were recorded in five observation wells. In order to prevent errors due to thermal convection, most of the observation wells recording temperature had to be backfilled with sand. During the 41-day production period, the temperature of the produced water varied from 55° to 33°C, and 65% of the injected thermal energy was recovered. At no time was an appreciable amount of free thermal convection observed in the storage formation. The dominant heat dissipation mechanisms appeared to be hydrodynamic thermal dispersion and possible mixing of cold and hot water induced by clogging and unclogging of the injection-production well. On the basis of laboratory and field studies, it was concluded that clogging of the injection well, which constituted the major technical problem during the experiment, was caused by the freshwater-sensitive nature of the storage aquifer. Due to the relatively low concentration of cations in the supply water, clay particles would swell, disperse, and migrate until they became trapped in the relatively small pores connecting the larger pores. Surging the pump and back washing the injection well would dislodge the clogging particles and temporarily improve the storage formation permeability. The phenomenon seems largely independent of temperature because it was reproduced in the laboratory with unheated water. It may, however, depend on pore velocity. Future research should be directed toward procedures for selecting storage aquifers that will have minimal susceptibility to clogging and other geochemical problems. Procedures for overcoming such difficulties are needed also because clogging and related phenomena will be more the rule than the exception. Designing an aquifer thermal storage system for maximum energy recovery would involve selecting an appropriate aquifer, analyzing the effects of hydrodynamic thermal dispersion and thermal convection if it is predicted to occur, anticipating geochemical problems, designing the optimum supply-injection-production well configuration and injecting a sufficiently large volume of heated water to realize economies of scale related to increasing volume-surface area ratio.

56 citations



Patent
19 Nov 1979
TL;DR: In this paper, a solar energy conversion panel is provided by means of which solar energy is recovered as converted electrical energy and also thermal energy, and a means for protecting the panel from wind damage is also disclosed.
Abstract: A solar energy conversion panel is provided by means of which solar energy is recovered as converted electrical energy and also thermal energy. An array of solar energy collectors direct solar energy received from the sun upon photovoltaic cells within the collectors. The photovoltaic cells convert a portion of this energy into electrical energy. The balance of the solar energy is recovered as thermal energy which is carried from the panel by a circulating fluid. Specific shapes and arrangements of energy collectors are disclosed by means of which the energy recovered may be maximized. A means for protecting the panel from wind damage is also disclosed.

41 citations


Journal ArticleDOI
01 Aug 1979-Energy
TL;DR: In this article, the authors presented the use of porous flat plate collectors to achieve efficient heat extraction from an energy absorbing solid, and its application to solar air heaters, and analyzed the temperature distribution within a gas-cooled porous flatplate having its surface exposed to the sun's energy.

41 citations


Journal ArticleDOI
TL;DR: In this paper, the shape of the melting front has been determined photographically, and the local heat transfer coefficients were measured using a shadowgraph technique, providing conclusive evidence of the important role played by natural convection on the timewise variation of the melt shape, the surface temperature and the instantaneous local and circumferentially averaged heat transfer coefficient around the imbedded heat sources.
Abstract: Melting from an array of three staggered, electrically heated cylinders imbedded in a paraffin (n-octadecane) has been studied. The shape of the melting front has been determined photographically, and the local heat transfer coefficients were measured using a shadowgraph technique. The experiments provide conclusive evidence of the important role played by natural convection on the timewise variation of the melt shape, the surface temperature and the instantaneous local as well as circumferentially averaged heat transfer coefficients around the imbedded heat sources. After a common solid-liquid interface is formed around the cylinders, natural convection circulation around each cylinder interacts strongly with the other two cylinders. The arrangement of heat sources affects significantly the melt shape but the circumferentially averaged instantaneous heat transfer coefficients differ only by about 10 percent for the two arrangements studied. The experimental findings indicate that natural convection effects are important and should be considered in analysis and design of systems involving phase change.

28 citations


Journal ArticleDOI
TL;DR: In this article, a closed regenerative EMF system is described and tested, which converts heat directly into electrical energy using a solution electrochemical reaction with a small polarizability and a large molar entropy change Δ S.

Journal ArticleDOI
J.A. Barker1, Daniel J. Auerbach1
TL;DR: In this article, energy exchange in thermal energy atom surface collisions is studied using impulsive (hard cube) and hard sphere (hard sphere) models, which reproduce the observed nearby linear relation between outgoing and incoming energies.

Journal ArticleDOI
TL;DR: In this paper, the electronic energy transfer in collisions between two diatomic molecules at thermal energy is treated by a distorted wave type calculation, where the predominating role of short-range interactions is assumed.
Abstract: The electronic energy transfer in collisions between two diatomic molecules at thermal energy is treated by a distorted‐wave type calculation. The predominating role of short‐range interactions is assumed. Potential energy curves and coupling terms have been estimated by configuration interaction between locally excited states. The method is applied to the system: N2(A 3Σu+)+CO(X 1Σ+) →N2(X 1Σg+) +CO(a 3Π). The results are compared with the available experimental data. A general study of the dependence of the rate constants and cross sections on the energy gap and temperature is given. Finally a comparison with the golden‐rule model and other quantum mechanical approximate calculations is presented.

Journal ArticleDOI
TL;DR: In this article, the authors used the results of analyses of movies of eruptions at Stromboli, Italy, and other available data to discuss the question of its energy partitioning among various energy transport mechanisms.
Abstract: The results of the analyses of movies of eruptions at Stromboli, Italy, and other available data are used to discuss the question of its energy partitioning among various energy transport mechanisms. Energy is transported to the surface from active volcanoes in at least eight modes, viz. conduction (and convection) of the heat through the surface, radiative heat transfer from the vent, acoustical radiation in blast and jet noise, seismic radiation, thermal energy of ejected particles, kinetic energy of ejected particles, thermal energy of ejected gas, and kinetic energy of ejected gas. Estimated values of energy flux from Stromboli by these eight mechanisms are tabulated. The energy budget of Stromboli in its normal mode of activity appears to be dominated by heat conduction (and convection) through the ground surface. Heat carried by eruption gases is the most important of the other energy transfer modes. Radiated heat from the open vent and heat carried by ejected lava particles also contribute to the total flux, while seismic energy accounts for about 0.5% of the total. All other modes are trivial by comparison.

Patent
04 May 1979
TL;DR: In this paper, the authors proposed a method of automatic contactors of precision engineering equipment, which is applicable to contact springs and is realized simply and economically by using localised regulated heating.
Abstract: The method of automatic contactors of precision engineering equipment is esp. applicable to contact springs and is realised simply and economically. A defined distortion of the part being adjusted is achieved without the application of force by using localised regulated heating. The thermal energy source is a laser whose light beam is directed to points of difficult access via deflection elements. These may take the form of mirrors or optical fibres. This method is applicable for contacts of all metals and organic materials. The thermal energy applied can be exactly controlled, thus facilitating accurate automatic adjustment. Because the heating and cooling times are short the distortion can be rapidly and continuously measured.

01 Jan 1979
TL;DR: A survey of passive solar heating experience, especially in the U.S., is provided in this article, where design approaches are reviewed and examples shown, and misconceptions are discussed.
Abstract: A passive solar energy system is one in which the thermal energy flow is by natural means, that is by radiation, conduction, or natural convection. A survey of passive solar heating experience, especially in the U.S., is provided. Design approaches are reviewed and examples shown. Misconceptions are discussed. Advantages are listed. The Los Alamos program of performance simulation and evaluation is described and a simplified method of performance estimation is outlined.

Patent
18 Apr 1979
TL;DR: In this article, a solar collector and heat exchanger are connected via a plurality of valves and a pump to a water storage tank, and temperature sensors associated with the solar collector, the heat exchange, and the storage tank operate a control system which controls the valves and pump to determine the phases of operation of the system.
Abstract: A solar energy conversion apparatus having two phases of operation which, in one phase, absorbs thermal energy from sunlight incident on the device, and in a second phase, absorbs energy from air in an attic-type space heated by solar radiation. The two phases may be utilized independently or in concert dependent upon conditions. A solar energy collector is disposed to collect and transfer incident solar energy to a fluid, such as water, flowing through the collector. A heat exchanger is disposed to permit flow of heated air therethrough from an attic-type space in a building, such air having been heated by solar energy incident on the roof of the building. The heat exchanger transfers heat from the air to a fluid, such as water, flowing therethrough. The solar collector and heat exchanger are connected via a plurality of valves and a pump to a water storage tank. Temperature sensors associated with the solar collector, the heat exchanger, and the water storage tank operate a control system which controls the valves and pump to determine the phases of operation of the system.

Patent
18 Oct 1979
TL;DR: Natural gas and thermal energy are produced from aquifers containing appreciable quantities of dissolved natural gas at or near saturation levels in the aquifer water, with or without associated dispersed vapor phase gas, using a particular method and apparatus.
Abstract: Natural gas and thermal energy are produced from aquifers containing appreciable quantities of dissolved natural gas at or near saturation levels in the aquifer water, with or without associated dispersed vapor phase gas, using a particular method and apparatus.

Patent
03 Jan 1979
TL;DR: In this paper, an integrated system for storing thermal energy, for space heating and cong and for power conversion is described which utilizes the reversible thermal decomposition characteristics of two hydrides having different decomposition pressures at the same temperature for energy storage and space conditioning and the expansion of high-pressure hydrogen for power converting.
Abstract: An integrated system for storing thermal energy, for space heating and cong and for power conversion is described which utilizes the reversible thermal decomposition characteristics of two hydrides having different decomposition pressures at the same temperature for energy storage and space conditioning and the expansion of high-pressure hydrogen for power conversion. The system consists of a plurality of reaction vessels, at least one containing each of the different hydrides, three loops of circulating heat transfer fluid which can be selectively coupled to the vessels for supplying the heat of decomposition from any appropriate source of thermal energy from the outside ambient environment or from the spaces to be cooled and for removing the heat of reaction to the outside ambient environment or to the spaces to be heated, and a hydrogen loop for directing the flow of hydrogen gas between the vessels. When used for power conversion, at least two vessels contain the same hydride and the hydrogen loop contains an expansion engine. The system is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators, but may be used with any source of heat, including a source of low-grade heat.

Patent
13 Jun 1979
TL;DR: In this paper, a gamma thermometer for use with a nuclear reactor is provided with two thermocouple junctions which are connected so as to output the difference voltage, which depends on the heating produced by the gamma-ray flux.
Abstract: A gamma thermometer for use with a nuclear reactor is provided with two thermocouple junctions which are connected so as to output the difference voltage. The two thermocouple junctions are spaced closely enough so that, considering the scale of the nuclear reactor, they experience the same gamma-ray flux. However, the thermal paths to a common heat sink for the two thermocouple junctions are different, so that the junctions exhibit a temperature difference which depends on, and therefore measures, the heating produced by the gamma-ray flux and, thereby, the gamma-ray flux itself. The gamma thermometer is built on a miniature scale, so that it can be traversed through a small, often dry, bore extending through the core of a nuclear reactor. The temperature difference mentioned above will be affected to some extent by the temperature of the common heat sink. Therefore, to increase accurate repeatability of computed measurement, a thermocouple junction is used to measure the temperature of the common heat sink and, further, a thermal heat bridge may be used to thermally link the common heat sink to the bore.

Journal ArticleDOI
TL;DR: In this paper, a project is developed in cooperation with the Federal Republic of Germany to test and prove the feasibility of the solar energy utilization as the source of the thermal energy required for a multistage flash evaporation plant.

01 Jan 1979
TL;DR: In this paper, the authors examined the effect of the heat of reaction on fluid temperature and acid penetration in a fracture and showed that the acid-rock reaction generates heat that causes the acid temperature itself to increase.
Abstract: In a fracture acidizing treatment, the acid reacts with the fracture faces. This acid-rock reaction generates heat that causes the acid temperature itself to increase. To predict accurately the temperature profile and acid spending rate of acid traveling down a hydraulically created fracture, this heat must be considered. Since the heat generated by reaction depends on the reaction rate, the thermal energy equation must be coupled with the acid spending equation. A model has been developed that for the first time examines the effect of the heat of reaction on fluid temperature and acid penetration in a fracture. Some sample calculations also have been made to illustrate the effects of the most important parameters on acid penetration in a fracture. 12 references.

Journal ArticleDOI
TL;DR: In this article, a potted Niobium Titanium superconducting magnet was constructed to determine the amount of energy input required to produce a quench, and several heaters were embedded in the winding and the energy required to drive the magnet normal was measured at various magnetic fields and current levels.
Abstract: The Navy is presently considering the use of fully potted Niobium Titanium superconducting magnets for the field windings of electric motors and generators. These magnets will operate at fields of 6.5 tesla and will be subjected to shipboard shock and vibration. This shock, vibration or other mechanical perturbation can result in energy being imparted to the superconductor within the magnet. If this energy is sufficiently large, the temperature will rise locally driving the conductor normal. If the normal zone is larger than the minimum propagating zone, thermal runaway will occur and a magnet quench will result. A potted superconducting magnet was constructed to determine the amount of energy input required to produce a quench. The magnet was wound from multifilament Nb-Ti conductor, reenforced with fiberglass cloth, and vacuum impregnated with epoxy resin. Several heaters were embedded in the winding and the energy required to drive the magnet normal was measured at various magnetic fields and current levels. Energy pulse widths were varied over a wide range to examine the effects of thermal diffusion and cover a broad spectrum of possible energy inputs. The results are compared with magnet operating characteristics and general design limits are discussed.

Journal ArticleDOI
12 Jan 1979-Science
TL;DR: The solar thermal energy stored in hydroelectric reservoir thermoclines is very large and greatly exceeds the gravitational hydroenergy of the surface water, even after limitations arising from the second law of thermodynamics have been taken into account.
Abstract: The solar thermal energy stored in hydroelectric reservoir thermoclines is very large and greatly exceeds the gravitational hydroenergy of the surface water, even after limitations arising from the second law of thermodynamics have been taken into account. Greatly enhanced power production can be obtained at present hydroelectric facilities if heat engines are adapted to exploit this large thermal energy resource.

Patent
23 Mar 1979
TL;DR: In this paper, a method and apparatus for heat-treating parts in a furnace system which uses a minimum total amount of energy is described, which includes a carburizer, a tempering furnace, and a part cooler.
Abstract: A method and apparatus are disclosed for heat-treating parts in a furnace system which uses a minimum total amount of energy. The self-contained, continuous heat-treating system includes components such as a carburizer, a tempering furnace, and a part cooler. Energy transfer between these and other components operable at different temperatures and/or energy requirements are used to maximize thermal efficiency of the system. Furnace components are provided and interconnected so that combustion air for radiant tube heaters supplying thermal energy to parts in a high temperature furnace such as a carburizer is preheated by exchanging heat in a part cooler and by recuperation of the carburizer exhaust; combustion products from the carburizer supply energy for reheating parts in a lower temperature furnace such as a tempering furnace; the tempering furnace exhaust is used for preheating parts prior to their entry into the carburizer; and energy transferred by the parts to a quench medium is used to heat water for subsequent washing of the parts. In one arrangement of components a tempering furnace is mounted on top of a carburizer as part of a compact multi-level configuration. In another arrangement the components form a single level system with energy transfer features and high thermal efficiencies similar to those of the multi-level system.



Patent
26 Sep 1979
TL;DR: In this article, a solar receiver with high thermal conductivity is mounted in an evacuated envelope so as to receive thermal energy and which is coated with a selective absorbing surface to minimize radiation has a heat transfer end which is surrounded by pyroceram or porcelain or other suitable material which extends into a container from which the heat produced by the solar energy is removed.
Abstract: A solar receiver in which a rod of high thermal conductivity is mounted in an evacuated envelope so as to receive thermal energy and which is coated with a selective absorbing surface so as to minimize radiation has a heat transfer end which is surrounded by a suitable material such as pyroceram or porcelain or other suitable material which extends into a container from which the heat produced by the solar energy is removed. The glass envelope surrounding the rod is attached by welding to the pyroceram cylinder and the heat transfer cavity is connected with an O-ring to the pyroceram cylinder so as to provide a liquid seal.

01 Jan 1979
TL;DR: The Argonne HYCSOS system is a two-hydride concept, operating as a chemical heat pump for storage and recovery of thermal energy for heating, cooling and energy conversion as discussed by the authors.
Abstract: The Argonne HYCSOS system is a two hydride concept, operating as a chemical heat pump for storage and recovery of thermal energy for heating, cooling and energy conversion. Hydrogen gas is transferred from one hydride bed by solar thermal energy input at a characteristic temperature to a second bed where hydrogen is absorbed and thermal energy is released at another temperature appropriate for the mode of operation in use. The basic HYCSOS concept uses thermal energy from a low grade source such as a solar collector to decompose a hydride, e.g., CaNi/sub 5/, and the released hydrogen is absorbed at a lower, intermediate, temperature and stored as a second hydride, e.g., LaNi/sub 5/H/sub 6/. The heat pump mode is the low temperature dissociation of the LaNi/sub 5/H/sub 6/ and the absorption of the hydrogen at the intermediate temperature. The intermediate temperature is available for space heating, using solar energy during periods of insolation and using low temperature ambient heat via heat pump action during other times. Operated in a reverse mode, the system can be used for refrigeration, eliminating the mechanical compression required in the operation of a conventional air conditioner. With three hydride heat exchangers containing the same hydridemore » cycling between a high temperature and a lower one, a continuous supply of high pressure hydrogen can be generated to do useful work in an expansion engine-dynamo unit supplying electricity, the hydrogen being absorbed after expansion on the alloy at a lower temperature. The current status of the HYCSOS system is discussed.« less

Journal ArticleDOI
TL;DR: In this paper, the potential of fluorescent collectors for thermal conversion is evaluated theoretically and the conversion efficiencies are calculated for various configurations and operating temperatures, showing that fluorescent collectors, although having a lower initial efficiency than flat plate collectors retain this efficiency at high operating temperatures and at low solar flux intensity.