Showing papers on "Thermal efficiency published in 1973"

Apparatus for the cold starting and warming run of spark plug-ignited internal combustion engines

Abstract: In each fuel injection valve forming part of a fuel injection apparatus and associated with an internal combustion engine, there is disposed an electric heater which transmits heat to the fuel by contact-type heat exchange The heat output of each heater is controlled by a device which processes input signals representing different engine variables

Solar energy power system

Abstract: A solar energy vapor (freon) powered system for generating electrical energy in which a portion of the heat absorbed from the sun in daylight is stored for use during darkenss by a thermal capacitor in which a mass of Pyrone, having a high thermal capacity, liquifies when heat is applied to it and goes through a solidification process to provide a heat output. A highly efficient solar boiler is constructed utilizing an anodized titanium surface and a particular combination of shaped boiler tubes and complementary reflectors. The overall efficiency of the system is further improved by a unique arrangement of heat recovery devices.

Power generating plant with nuclear reactor/heat storage system combination

Abstract: Excess heat output of a nuclear reactor is stored at high temperature. This stored heat is then used to generate steam to operate a turbine-generator during high power demand periods. An arrangement is described herein in which a fluoride salt fusion heat storage system is used from which heat is retrieved by circulating liquid lead therethrough. The liquid lead heat retrieval circuit includes a steam boiler in which steam for operation of a turbine-generator is generated using heat extracted from the heated liquid lead.

Thermodynamic cycles of carbon dioxide plant with an additional turbine after the regenerator

Abstract: Translated from Teploenergetika; 20: No. 3, 86-87(Mar 1973). Further improvement in CO/sub 2/ as a working medium in gas--liquid cycles to obtain higher efficiency gain in power plants was investigated. The CO/sub 2/ cycle is only economic with high inlet turbine pressures and a low condensation temperature. Further efficiency is gained if the working medium after being cooled in the regenerator, instead of passing into a cooler, passes into a turbine and then to a condenser or cooler. Efficiency calculations were made for the simple gas-liquid cycle, cycle with superposed turbine, cycle with combined regeneration, and with gas cycle. An investigation was also made into the effect of the temperature head at the cold end of the regenerator on the thermodynamic efficiency of the cycles for an initial cycle temperature of 813 K. (MCW)

Apparatus for burning materials of cement and the like

Abstract: An apparatus for burning the materials of cement and the like is disclosed wherein a calcining furnace is constructed so as to attain the optimum thermal efficiency, and an air inlet provided with means for selectively opening or closing the inlet is attached to a duct for conveying combustion air from a cooling device to the calcining furnace so that the introduction of the combustion air may be controlled.

A Potassium-Steam Binary Vapor Cycle for Better Fuel Economy and Reduced Thermal Pollution

Abstract: Both fuel supply and thermal pollution considerations that are becoming progressively more important strongly favor the development of a higher temperature, and more efficient, thermodynamic cycle for electric power plants. About 200,000 hr of operation of boiling potassium systems, including over 15,000 hr of potassium vapor turbine operation under the space power program, suggest that a potassium vapor topping cycle with a turbine inlet temperature of ∼1500 deg F merits consideration. A design study has been carried out to indicate the size, cost, and development problems of the new types of equipment required. The results indicate that a potassium vapor cycle superimposed on a conventional 1050 deg F steam cycle would give an overall thermal efficiency of about 54 percent as compared to only 40 percent from a conventional steam cycle. Thus the proposed system would have a fuel consumption only 75 percent and a heat rejection rate only 50 percent that of a conventional plant. Further, it appears possible that the capital charges for the proposed plant might be lower than those for a conventional plant. A high grade fuel oil or gas will be required, but this is likely to be necessary anyway to meet increasingly stringent limitations on SO2 , NOx , and ash emissions.

Direct conversion of thermonuclear plasma energy by high magnetic compression and expansion

Abstract: We consider the useful work output from the magnetic compression, decompression and α-particle energy deposition of a single cycle of a D-T θ-pinch reactor. The intrinsic thermodynamic efficiency of the direct conversion cycle from α-particle energy to work is 62%. The direct-conversion output work is available to the reactor system at essentially 100% efficiency, and has an appreciable effect on the circulating power fraction and plant efficiency.

Supercharger for internal combustion engine carburetion

Abstract: Apparatus for supercharging the air and gas fuel mixture of internal combustion engines wherein the dynamic supercharging produced is self-generated as cylinder charging pressures are created by the vortex motion of the moving gases. The supercharger utilizes the inertial characteristics of the flowing fuel gases as produced by the vortexing of the gases within a plurality of longitudinal passages. The vortexing gases within the passages are introduced into a larger chamber creating additional vortexing resulting in superior air and gas mixing and a high thermal efficiency within the combustion chamber.

Rotary internal engines

Abstract: An improved rotary internal combustion engine utilizing a new and improved cycle of operation which includes six phases: intake, compression, combustion, after burn, adiabatic expansion, and exhaust. The purpose of both the after burn phase and the adiabatic expansion phase is to increase the thermodynamic efficiency of the engine and also to reduce the pollution products of the exhaust. The after burn phase achieves this purpose by injecting jets of hot compressed air into the hot combustion phase products at the end of the combustion phase and thus promotes more complete combustion. The adiabatic expansion phase serves to increase the engine efficiency by substantially allowing the combustion products to expand inside the engine thus converting the heat energy into useful mechanical energy.

The Inverted Brayton Cycle for Waste-Heat Utilization

Abstract: The inverted Brayton cycle, which can be simply defined as one in which hot gas is first expanded through a turbine to low pressure, is then cooled at constant pressure, and lastly, is recompressed to the initial pressure, has been shown to give attractive incremental gains in thermal efficiency, and large returns on investment, when added to a conventional shaft-power gas turbine exhausting into a waste-heat boiler. When the inverted Brayton cycle is applied by itself as a method of obtaining shaft power from the hot waste gas stream, there appears to be range of temperature and pressure ratios at which the cycle is competitive with other methods of waste-heat utilization.Copyright © 1973 by ASME

Exploratory study of several advanced nuclear-MHD power plant systems.

Abstract: In order for efficient multimegawatt closed cycle nuclear-MHD systems to become practical, long-life gas cooled reactors with exit temperatures of about 2500 K or higher must be developed Four types of nuclear reactors which have the potential of achieving this goal are the NERVA-type solid core reactor, the colloid core (rotating fluidized bed) reactor, the 'light bulb' gas core reactor, and the 'coaxial flow' gas core reactor Research programs aimed at developing these reactors have progressed rapidly in recent years so that prototype power reactors could be operating by 1980 Three types of power plant systems which use these reactors have been analyzed to determine the operating characteristics, critical parameters and performance of these power plants Overall thermal efficiencies as high as 80% are projected, using an MHD turbine-compressor cycle with steam bottoming, and slightly lower efficiencies are projected for an MHD motor-compressor cycle

Integration of modern machinery systems

Abstract: With the advent of gas turbine prime movers for both propulsion and electric power generation, new methods of optimizing thermal efficiency are needed if weight and cost limits are to be achieved by new ship designs without sacrificing operational capability. The balance of primary power generation from fuel and secondary power generation utilizing other energy media must be reviewed. Where once the basic shipboard energy conversion was Bunker C fuel into steam within a large boiler, using steam as the energy medium for all power and heating use, we now have machinery systems that convert fuel into energy at several subsystem levels, i.e. propulsion, electric power, auxiliary steam and so forth. The design challenge for today's machinery system engineer is to optimize thermal recovery from fuel much the same as economizers, etc. that were used in previous steam plant designs. This can be done by making one system dependent upon another for its source of energy. However the design constraint demanded by NAVY combatant ships is that operational flexibility, vulnerability protection and reliability/maintainability/availability goals for each dependent system must be maintained should the primary energy source system fail. This paper presents an engineering approach to generating and evaluating alternative machinery designs within the structure of a set of ship design criteria categories. These categories are defined and examples of machinery system design objectives given. A design process is then proposed which includes determination of energy requirements, identification of alternate energy generation/conversion hardware and verification of adequate energy supply under all operating modes. Discussion is given to the importance of selecting the proper energy medium (fuel, electricity, steam, etc.) for each functional service if energy generation and energy absorption are to be efficiently matched. An evaluation approach is then presented which compares total performance of candidate designs on a system-level basis. Finally, the paper describes two recent ship designs where integration of machinery systems has taken place: the Canadian DDH-280 Class Destroyer and the U.S. Navy DD-963 Class Destroyer. Elements in the “trade-off” studies for these ships are reviewed and design advantages discussed.

Alternative power plants

Abstract: A REVIEW IS MADE OF AVAILABLE DATA ON FUEL ECONOMIES OF THE CURRENT INTERNAL COMBUSTION ENGINE-POWERED AUTOMOBILES AND OF THOSE WITH ALTERNATIVE POWERPLANTS. COMPARISONS OF FUEL ECONOMIES OF ALL THESE ENGINE SYSTEMS ARE MADE ON THE BASIS OF THE VEHICLE WEIGHT/ENGINE DISPLACEMENT, AND THE VEHICLE WEIGHT ALONE. THE THERMAL EFFICIENCIES ARE ALSO COMPARED. IT IS SHOWN THAT SEVERAL VERSIONS OF THE DIESEL ENGINE WHICH MEET THE 1975 CLEAN AIR ACT STANDARDS AND WHICH ARE ON THE ROAD TODAY ARE MORE EFFICIENT THAN THE CONVENTIONAL INTERNAL COMBUSTION ENGINE OF 1973. MOREOVER, PROTOTYPES OF OTHER ALTERNATIVE SYSTEMS, USING OTHER CYCLES (BRYTON, RANKINE, STIRLING) UNDER DEVELOPMENT ARE ALSO PROJECTED TO PROVIDE HIGHER EFFICIENCIES THAN THE CONVENTIONAL INTERNAL COMBUSTION ENGINE OF 1973. ALL COMPARISONS ARE MADE USING THE FEDERAL DRIVING CYCLE AS A COMMON REFERENCE. /AUTHOR/

Power station cooling system - with reduced overall thermal losses to increase thermal efficiency

Abstract: The working fluid in either a thermal or nuclear power station is recondensed in the normal way and the heat energy given up to the cooling water is extracted by cascaded heat pumps the resultant high level heat energy being either fed back into the steam raising etc system (eg feed water heating) or used externally eg district heating system so that there is maximum use made of the heat energy fed into the system initially and minimum disturbance to the environment Cooling towers and heat engines for energy conversion may be associated with the heat pumps

Analysis of a combined refrigerator-generator space power system

Abstract: Compatibility of the Brayton power and refrigeration cycles is considered. Performance of the power- and cryo-loop is plotted against compressor pressure ratio. The power- and cryo-loop performance is determined by dividing the compressor work between the two loops in proportion to mass flow rate. Cycle efficiency is defined as the ratio of shaft power available in the power loop to the net thermal input from the heat source. The available shaft power is the excess of the power turbine work over the compressor work needed in the power loop. The best power loop efficiency occurred at a compressor pressure ratio of 1.8, and the best cryo-loop performance was at a compressor pressure ratio of 2.1. Good individual cycle performance occurred over a fairly large range in compressor pressure ratio.

Total energyߞa realistic answer to fuel conservation

Abstract: With the world's limited supplies ot fuel and ever increasing fuel costs, there is logic in considering combined heat and power generation. Industry is already installing total-energy schemes because ot economic savings, and it is also in the interests ot the public supply authority to make use ot the waste heat in both thermal and nuclear power stations in order to improve their thermal efficiency. District heating is one way of doing this.

Closed Cycle MHD for Central Station Power with Fossil or Nuclear Fuels.

Abstract: A closed--cycle MHD generator using a noble gas with alkali metal vapor as the working fiuid, when used as a topping unit for a conventional steam plant, can yield cycle efficiencies in excess Of 60% at peak stagnation temperature of 3000 deg F. While high enough for substantial gains in thermodynamic efficiency, this temperature is relatively low for an electrically conducting gas and conductivity is achieved by decoupling electron temperature from gas temperature. A ceramic regenerative heat exchanger supplies thermal energy to the working fluid. The latter can be any clean fossil fuel, preferably low BTU (about 150 BTU/ SCF) coal gas. With multi-stage combustion, pulverized coal is also a possible fuel. On a long range basis, closed cycle MHD is ideally suited for high temperature gas cooled fission reactors and probably, also to fusion reactors. The closed cycle MHD generator is adaptable to the Brayton cycle, the regenerative Brayton cycle and eventually the Rankine cycle. (auth)