Showing papers on "Thermal energy published in 1981"

Closed cycle gas turbine for gaseous production

Abstract: A gas turbine is employed in a combined cycle system to produce one or more chemically useful products. Selected exhaust gases are fed back into the gas turbine compressor so as to establish a stable mixture of working fluid constituents for the gas turbine. The gas turbine is preferably configured in a combined cycle arrangement and both mechanical and thermal energy is extracted from the flow of gases through the load turbine, this energy being used in the production of useful process fluids. The methods and apparatus of the present invention are particularly unique in that here the principal output of the combined cycle plant is not electrical energy but rather valuable chemical products. In short, the gas turbine is being employed as a high-temperature reactor from which both mechanical and thermal energy may be extracted as a result of the energy in the gaseous reaction products.

Nested thermal reservoirs with heat pumping therebetween

Abstract: An assembly of nested thermal reservoirs has an inner reservoir at an extreme temperature surrounded by one or more reservoirs at moderate temperatures. Over time, heat flow would equilibrate reservoir temperatures thereby loosing available thermal energy. At least a portion of the heat lost by the inner to an outer reservoir is restored by a heat pump operating therebetween.

Thermal heat flux in a plasma for arbitrary collisionality

Abstract: The thermal heat flux along a uniform magnetic field due to a temperature gradient is calculated using a Monte Carlo solution to the Fokker–Planck equation. This numerical solution, which is computed for a particular electron temperature profile, is valid for arbitrary mean‐free‐path, λmfp. The calculated heat flux makes a smooth transition between the analytic expressions for the short and long λmfp limits.

Chemical heat pump

Abstract: A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.

Heat-producing elements with heat pipes

Abstract: The PC-boards are contained in sealed enclosures, and serially effective heat pipe systems conduct thermal energy from the respective sources of development (e.g., power transmitters) to the top and from there to a heat pump system. Stacking such units and operating the heat transfer partially in parallel is disclosed.

Thermal heat storage and cooling system

Abstract: An improved heat storage and cooling system utilizing a conventional solar energy collector as a heat source, a thermal mass of stacked cement blocks with interal horizontally aligned air passageways for warm or cool air storage and a dual-purpose structural wall of staggered hollow cement blocks to generate cool air. The system is self-contained and multi-functional, located either in a fully bermed room adjacent on any side to the area to be serviced or in a basement room embedded in the earth beneath the area to be serviced. The circulation system of metal ducts, pipes, air handler, circulating fan, gas heater and dampers interconnects the solar energy collector, the thermal mass and cooling walls to provide seven modes of operation for the storage of heat or cold and the circulation of warm or cool air as circumstances may require.

Thermoelectric cooling of magnetic head assemblies

Abstract: The temperature of a magnetic head assembly is reduced by active heat transfer accomplished by a thermoelectric cooling element positioned between and in contact with the head assembly housing and the head assembly. The housing serves as a heat sink from which thermal energy is diffused.

Hydrogen generation as fuel by use of solar ultraviolet light process

Abstract: A feasible and economic method of producing hydrogen and oxygen as potential fuels, from water. The process employs as the energy source, sunlight, which is separated into its infrared portion and its ultraviolet light portion. These are concentrated, and in a first stage the infrared is used to heat the water, under pressure to a superheated steam which is contacted with a steam decomposition catalyst in a chamber which is subjected to concentrated ultraviolet light. The result is separation of the water by a combination of thermal energy and photolytic effect into its component elements, hydrogen and oxygen, which can be collected individually and used as fuel sources.

Heat and gas flow analysis in semiaerobic landfill

Abstract: Flow parameters in governing differential equations include thermal conductivity, rate of energy production, heat transfer coefficient, and aeropermeabilities in solid waste. These are determined by the least squares using the simplex and finite element methods. The minimizing procedure requires measured values from the experiment such as temperatures in the solid waste, air influx from the leachate collection line at the bottom of the experimental vessel, and the surrounding temperature and pressure. Computed results show that thermal energy is produced in a semi-elliptic region of solid waste above the air inlet by aerobic biochemical reaction, and the vertical aeropermeability is ten times larger than the lateral one. The method applies to the design of sanitary landfill subjected to the natural convection of air.

Apparatus for controlling the braking effect of a hydraulic retarder

Abstract: A hydraulic retarder, especially for an automotive vehicle, comprising a control valve which regulates the pressure of the hydraulic fluid supplied to the decelerator which can be connected to a heat exchanger for dissipating the thermal energy generated by the retardation of the vehicle. According to the invention a regulating valve is additionally provided for controlling the maximum pressure in dependence upon temperature and in response to a temperature sensor. The device thus limits the maximum retarder effect in accordance with the temperature of the hydraulic medium and hence the utility of the heat exchanger to dissipating the braking energy.

Energy converting device

Abstract: PURPOSE:To enhance the converting efficiency, reduce noises and vibrations, and to raise the degree of freedom in designing by converting mechanical energy into thermal energy through the theory of electromagnetic inductive heating. CONSTITUTION:A cylindrical rotor 3f consisting of magnetic electroconductive material is fixed to a rotary shaft 3b through a disc 3e. A group of permanent magnets 3g are fixed to a container 3c filled with a thermomedium 4 through a ring-shaped yoke 3h in such an arrangement that N and S poles are placed alternately in the circumferential direction. Because an alternating flux, chain crossing with the cylindrical rotor 3f with a micro gap interposed, is generated in the heat converter 3 by said group of permanent magnets 3g, an eddy current generated by electromagnetic inductive action flows through the cylindrical rotor 3f revolving, that involves a loss. That is to say, the wind energy transmitted to the rotary shaft 3b of the heat converter 3 through the windmill 1 is converted into thermal energy by means of the theory of electromagnetic inductive heating.

Thermal energy compression system for heat pumps

Abstract: A thermal energy compression system wherein the refrigerant in a heat pump or air-conditioner is compressed by thermal energy in the compression system rather than by work in a standard compressor. The compression uses an intermittent compression process with a solid absorbent. The vapor is absorbed by an absorbent at relatively low temperature and ejected as the absorbent temperature is raised and a set of one way valves limits flow to one direction so as to improve heat transfer requirements, to allow for molecular sieve-refrigerant matching, minimizing non-producing mass, solving thermal fatigue and shock problems, and use of the system in parallel with a standard compressor, automobile air-conditioning applications and truck refrigeration applications.

Evaluation of flat-plate photovoltaic thermal hybrid systems for solar energy utilization.

Abstract: The technical and economic attractiveness of combined photovoltaic/thermal (PV/T) solar energy collectors was evaluated. The study was limited to flat-plate collectors since concentrating photovoltaic collectors require active cooling and thus are inherently PV/T collectors, the only decision being whether to use the thermal energy or to dump it. it was also specified at the outset that reduction in required roof area was not to be used as an argument for combining the collection of thermal and electrical energy into one module. Three tests of economic viability were identified, all of which PV/T must pass if it is to be considered a promising alternative: PV/T must prove to be competitive with photovoltaic-only, thermal-only, and side-by-side photovoltaic-plus-thermal collectors and systems. These three tests were applied to systems using low-temperature (unglazed) collectors and to systems using medium-temperature (glazed) collectors in Los Angeles, New York, and Tampa. For photovoltaics, the 1986 DOE cost goals were assumed to have been realized, and for thermal energy collection two technologies were considered: a current technology based on metal and glass, and a future technology based on thin-film plastics. The study showed that for medium-temperature applications PV/T is not an attractive option in any of the locations studied.more » For low-temperature applications, PV/T appears to be marginally attractive.« less

Enthalpy restoration in geothermal energy processing system

Abstract: A geothermal deep well energy extraction system is provided of the general type in which solute-bearing hot water is pumped to the earth's surface from a relatively low temperature geothermal source by transferring thermal energy from the hot water to a working fluid for driving a primary turbine-motor and a primary electrical generator at the earth's surface. The superheated expanded exhaust from the primary turbine motor is conducted to a bubble tank where it bubbles through a layer of sub-cooled working fluid that has been condensed. The superheat and latent heat from the expanded exhaust of the turbine transfers thermal energy to the sub-cooled condensate. The desuperheated exhaust is then conducted to the condenser where it is condensed and sub-cooled, whereupon it is conducted back to the bubble tank via a barometric storage tank. The novel condensing process of this invention makes it possible to exploit geothermal sources which might otherwise be non-exploitable.

Thermally Induced Acoustic Oscillations in a Pipe : 1st Report : Oscillations Induced by Plane Heat Source in Air Current

Abstract: Thermally induced acoustic oscillations in a pipe have been studied analytically and experimentally. Temperature distributions have been obtained near a heat source in a uniform flow with an acoustic field by solving heat-conduction equations. The temperature change of gas causes a volumetric change, and it may convert thermal energy to acoustic energy under certain conditions which have already been clarified only qualitatively. Using the calculated temperature distributions, the amount of converted energy in a cycle has been computed and proved to be a function of the heat source location, the current velocity, the frequency and the thermal diffusivity of the fluid. Experimental results agreed well with the analysis where the modified current velocity is used considering the boundary-layer around the heater. Some other characteristics of the oscillation have been discovered ; for example, the growth rate of oscillation changes when turbulent transition occurs over a certain amplitude.

Solar collector for heating purposes

Abstract: A solar collector transfers the thermal energy of solar radiation to a liquid which acts as thermal vehicle, said liquid being moved by a thermo-convective action in a closed circuit so transferring through heat exchange the absorbed heat to a fluid contained in a vessel. This solar collector, compact in structure and low in cost, is provided with a valve which is apt to allow said thermo-convective action of the liquid in one sense, while blocking it in the opposite sense.

Energy transport by weak electrostatic drift fluctuations

Abstract: Energy transport from weak electrostatic microfluctuations, driven unstable by density and temperature gradients perpendicular to a uniform magnetic field in a Vlasov plasma, is calculated. Using the local approximation and assuming resonance broadening as the saturation mechanism, a consistent procedure is used to evaluate and compare the cross‐field energy transport due to enhanced microfluctuations from the universal, lower hybrid, and ion‐acoustic density drift, and the ion, electron, and lower hybrid temperature drift instabilities. If a temperature gradient is the primary source of free energy, the resultant enhanced fluctuations cause a cross‐field thermal energy loss rate which is much greater than the energy loss rate associated with cross‐field particle transport.

Method and apparatus for absorption refrigeration

Abstract: An absorption refrigeration method and apparatus is described wherein a heated fluid for supplying operating thermal energy to a generator of the apparatus is preheated to a temperature for efficient operation of the apparatus. Preheating is provided by vaporizing a previously heated liquid phase fluid, compressing the vapor and condensing the compressed vapor in heat exchanging relationship with the generator. A rotary pump is provided for enhancing efficiency. In a preferred embodiment, the fluid is heated by a solar energy source.

Process and plant equipment for the short-term propulsion of one or several turbines coupled to an air and/or nitrous gas compressor in a plant for the production of nitric acid

Abstract: A process and a plant are disclosed whereby nitric acid is produced by the catalytic combustion of ammonia with air to form nitrous gases which are contacted with water in an absorption zone to form nitric acid Gas flow into and through the plant is maintained by a compressor system powered by turbines that are propelled by the heat energy released during ammonia combustion In accordance with the present invention, a portion of the ammonia combustion heat energy is stored using heat accumulating means positioned at various possible locations throughout the system Such stored heat provides a thermal energy reserve available to power the compressor turbines for a short period of time in the event that ammonia combustion is discontinued

Device for the simultaneous production of electricity and thermal energy from the conversion of light radiation

Abstract: A device for the simultaneous conversion of light energy into electrical energy and thermal energy utilizing a liquid-junction semiconductor photocell (PEC) utilizing a novel photoactive true solid/solid solution semiconductor mixed metal oxide material electrode so as to adjust the band gap and/or optical response properties of the electrode to be more closely attuned to the major output portion of the solar spectrum as well as lowering the cost of production and being environmentally sound.

Economic analysis of community solar heating systems that use annual cycle thermal energy storage

Abstract: The economics of community-scale solar systems that incorporate a centralized annual cycle thermal energy storage (ACTES) coupled to a distribution system is examined. Systems were sized for three housing configurations: single-unit dwellings, 10-unit, and 200-unit apartment complexes in 50-, 200-, 400-, and 1000-unit communities in 10 geographic locations in the United States. Thermal energy is stored in large, constructed, underground tanks. Costs were assigned to each component of every system in order to allow calculation of total costs. Results are presented as normalized system costs per unit of heat delivered per building unit. These methods allow: (1) identification of the relative importance of each system component in the overall cost; and (2) identification of the key variables that determine the optimum sizing of a district solar heating system. In more northerly locations, collectors are a larger component of cost. In southern locations, distribution networks are a larger proportion of total cost. Larger, more compact buildings are, in general, less expensive to heat. For the two smaller-scale building configurations, a broad minima in total costs versus system size is often observed.

Intake air cooler of internal-combustion engine

Abstract: PURPOSE:To improve thermal efficiency of an engine, by operating an absorption refrigerator with thermal energy of exhaust gas, cooling water, etc., emitted from an internal-combustion engine, and efficiently cooling suction air through a heat exchanger. CONSTITUTION:Thermal energy, collected from exhaust gas by an exhaust heat exchanger 42, is fed to a generator heat exchanger 43 via a pipe line 45 through a medium of water and the like, and a generator of an absorption refrigerator 41 is heated to operate the absorption refrigerator 41. Operation of the absorption refigerator 41 cools an evaporator heat exchanger 44, provided in the part of an evaporator, to cool a medium of water and the like, flowing in a pipe line 46 from the evaporator heat exchanger 44 to a heat exchanger 40, and intake air, flowing in intake pipes 38, 39, can be cooled.