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Showing papers on "Thermal efficiency published in 1985"


Book
01 Jan 1985
TL;DR: In this paper, the authors discuss the importance of energy storage and its application in various types of storage, such as storage in phase change materials (PCM) and storage in a battery.
Abstract: 1 Importance and modes of energy storage.- 1.1 The importance of energy storage.- 1.2 Influence of type and extent of mismatch on storage.- 1.3 Size and duration of storage.- 1.4 Applications.- 1.4.1 Stationary applications.- 1.4.2 Transport applications.- 1.5 Quality of energy and modes of energy storage.- 1.6 Thermal energy storage.- 1.6.1Sensible heat storage.- 1.6.2 Storage in phase change materials (PCM).- 1.7 Mechanical energy storage.- 1.7.1 Storage as potential energy.- 1.7.2 Storage as kinetic energy.- 1.7.3 Energy storage in a compressed gas.- 1.8 Electrical and magnetic energy storage.- 1.8.1 Storage in electrical cap ac i tors.- 1.8.2 Storage in electromagnets.- 1.8.3 Storage in magnets with superconducting coils.- 1.8.4 Storage in a battery.- 1.9 Chemical energy storage.- 1.9.1 Synthetic fuels.- 1.9.2 Thermochemical storage.- 1.9.3 Electrochemical storage.- 1.9.4 Photochemical storage.- References.- 2 Sensible heat storage.- 2.1 Sensible heat storage basics.- 2.2 Sensible heat storage and type of load.- 2.3 Sensible heat storage media.- 2.4 Well-mixed liquid storage.- 2.5 Stratified liquid storage.- 2.5.1 Analytical studies on thermally stratified hot water tanks.- 2.5.2 Experimental studies on thermally stratified hot water storage tanks.- 2.5.3 Forced stratification in liquids.- 2.6 Containers for water storage.- 2.7 Packed bed storage system.- References.- Appendix -I.- Appendix - II.- 3 Latent heat or phase change thermal energy storage.- 3.1 Basics of latent heat storage.- 3.1.1 Heat of fusion (Latent heat).- 3.1.2 Employment of latent heat storage system.- 3.2 Liquid-solid transformation.- 3.2.1 Nucleation and supercooling.- 3.2.2 The rate of crystal growth.- 3.2.3 Types of solidification or crystallization.- 3.2.4 Melting and freezing characteristics.- 3.2.5 Interpretation of freezing curves.- 3.2.6 Relative rates of heat and mass transport.- 3.2.7 Binary phase diagrams.- 3.3 Phase change materials (PCM).- 3.3.1 Solid-solid transitions.- 3.3.2 Solid-liquid transformations.- i) Salt hydrates.- ii) Other inorganic compounds.- iii) Paraffins.- iv) Non paraffin organic solids.- v) Clathrate and semi-clathrate hydrates.- vi)Eutectics.- 3.4 Selection of PCM.- 3.5 Storage in salt hydrates.- 3.5.1 Nucleation and crystallization.- 3.5.2 Incongruent melting.- 3.5.3 Thickening agents.- 3.5.4 Some promising salt hydrates and the binary phase diagrams.- 3.6 Prevention of incongruent melting and thermal cycling.- 3.6.1 Thickening agents.- 3.6.2 Extra water principle.- 3.6.3 Rolling cylinder method.- 3.6.4 Adding SrCl2 6H2 C in CaCl2 H2O system.- 3.7 Storage in paraffins.- 3.8 Heat transfer in PCM.- 3.8.1 Freezing of tops of ponds.- 3.8.2 An approximate analytical model for a periodic process.- 3.8.3 Heat-exchange with fluid-flow between trays holding PCM.- 3.9 Heat exchange arrangement and containment of PCM.- 3.9.1 Encapsulation of PCM.- 3.9.2 Containment.- 3.9.3 Compatibility.- 3.9.4 Special heat exchangers for PCM.- (A) Passive systems.- (B) Active systems.- 3.10 Storage in PCM undergoing solid-solid transition.- 3.10.1 Storage in modified high density polyethylene (HDPE).- 3.10.2 Storage in layer perovskites and other organometallic compounds.- 3.11 Heat of solution storage and heat exchangers.- 3.11.1 Crystallization from saturated solution.- 3.11.2 Heat exchangers in heat-of-solution storage system.- References.- 4 Chemical energy storage.- 4.1 Introduction.- 4.2 Selection Criterion.- 4.2.1 Thermodynamic considerations.- 4.2.2 Reversibility.- 4.2.3 Reaction rates.- 4.2.4 Controllability.- 4.2.5 Ease of storage.- 4.2.6 Safety.- 4.2.7 Availability and Cost.- 4.2.8 Product separation.- 4.2.9 Reaction with water and oxygen.- 4.2.10 Technology.- 4.2.11 Catalyst availability and lifetime.- 4.3 Energy storage in thermal dissociation type of reactions.- 4.3.1 Thermal dissociation of SO3.- 4.3.2 Dissociation of Ammonia.- 4.3.3 Thermal dissociation of inorganic hydroxides.- 4.3.4 Thermal decomposition of carbonates.- 4.3.5 Decomposition of sulfates.- 4.3.6 Thermal decomposition of CS2.- 4.3.7 Organic hydrogenation/dehydrogenation reaction.- 4.3.8 Thermal dissociation of ammoniated salts.- 4.3.9 Oxides-Peroxides and super oxides decomposition.- 4.3.10 Hydride decomposition.- 4.3.11 The reaction N2 O4 2N0+02.- 4.4 Methane based reactions.- 4.5 Heat transformation (HT) and chemical heat pumps (CHP).- 4.5.1 Working materials for CHP and HT.- 4.5.2 Thermal efficiency of CHP cycles.- 4.5.3 Ammoniates based CHP.- 4.5.4 Salt hydrates in chemical heat pump.- 4.5.5 Hydrides in CHP and HT.- 4.5.6 Methanolated salts.- 4.5.7 Heat of solution systems.- 4.6 Three step approach.- 4.7 Energy storage by adsorption.- References.- 5 Longterm energy storage.- 5.1 Solar ponds.- 5.1.1 Classification of solar ponds.- i) Shallow solar pond.- ii) Salt gradient solar ponds.- iii) Partitioned solar pond (PSP).- iv) Viscosity stabilized ponds.- v) Membrane stratified solar pond.- vi) Saturated solar pond.- 5.1.2 Thermal stability of solar ponds.- 5.1.3 Salt properties.- 5.1.4 Passage of solar insolation into solar pond.- 5.1.5 Creation and maintenance of solar pond.- 5.1.6 Performance analysis of a solar pond.- 5.1.7 Heat extraction.- 5.1.8 Applications.- i) Space heating.- ii) Domestic water or swimming pool heating.- iii) Industrial process heat.- iv) Power production.- v) Desalination.- 5.1.9 Some remarks.- 5.2 Energy storage in aquifers.- 5.2.1 Operational strategies.- 5.2.2 Theoretical studies.- 5.2.3 Characteristics of the aquifer.- 5.3 Heat storage in underground water tanks.- 5.4 Heat storage in the ground.- References.- 6 Energy storage in building materials.- 6.1 Introduction.- 6.2 Basic passive designs.- 6.2.1 Direct gain systems.- 6.2.2 Convective loops.- 6.2.3 Thermal storage walls.- 6.2.4 Roof ponds.- 6.2.5 Attached sunspace.- 6.3 PCM in building panels.- 6.4 Experiments on PCM building panels.- 6.5 Applications.- References.- 7 High temperature heat storage.- 7.1 Introduction.- 7.2 Techniques for thermal energy storage.- 7.3 Sensible heat storage systems.- 7.3.1 Rock bed storage system.- 7.3.2 Rock bed-liquid (Dual medium) storage system.- 7.3.3 Two stage thermal storage in unpressurized liquids.- 7.3.4 Molten slag storage system.- 7.3.5 Thermal storage in large hollow steel ingots.- 7.3.6 Thermal energy storage in sand (fluidized bed).- 7.4 Phase change energy storage systems and ceramic pellets.- 7.4.1 Phase change salt and ceramic 570 pellets with air as working fluid.- 7.4.2 Phase change salt/metal storage systems.- 7.4.3 Phase change storage material with heat exchanger.- 7.4.4 Energy storage boiler.- 7.4.5 Storage heat in PCM and use of scraper for removing solid boundary layer.- 7.5 Chemical reactions.- 7.5.1 Catalytic decomposition reactions.- 7.5.2 Thermal dissociation reactions.- References.- 8 Testing of thermal energy storage system.- 8.1 Introduction.- 8.2 Historical development.- 8.3 Related studies.- 8.4 Basis and evolution of testing procedures.- 8.5 Standard procedure.- 8.5.1 ASHRAE 94-77.- 8.5.2 NBSIR 74-634.- 8.6 Some comments.- References.- Appendices.- Appendix 1 Conversion of units.- Appendix 2 Physical properties of some solid materials.- Appendix 3 Physical properties of some building and insulating materials.- Appendix 4 Physical properties of some liquids.- Appendix 5 Physical properties of some liquid metals.- Appendix 6 Physical properties of saturated water.- Appendix 7 Physical properties of saturated steam.- Appendix 8 Physical properties of some gases.- Appendix 9 Physical properties of dry air at atmospheric pressure.- Appendix 10 Freezing points of aqueous solutions.- Appendix11 Properties of typical refrigerants.- Appendix 12 Storage capacities.- Appendix 13 Properties of some promising latent-heat thermal energy storage materials.- Appendix 14 Solubility behavior of candidate salts for salt-gradient solar pond.

285 citations


Journal ArticleDOI
TL;DR: In this article, a simple model is presented for a heat engine, where the power output is limited by the rate of heat supply (and/or heat release) and the model leads to a variety of results such as the Carnot law, the Curzon-Ahlborn efficiency, and the Castans efficiency.
Abstract: In the present paper a simple model is presented for a heat engine, where the power output is limited by the rate of heat supply (and/or heat release). The model leads to a variety of results. Some of them are established laws such as the Carnot law, the Curzon–Ahlborn efficiency, and the Castans efficiency. Other results are new, and are related to phenomena as different as geothermal energy conversion and the Penfield paradox of electric circuits.

282 citations


Proceedings ArticleDOI
TL;DR: In this paper, the rate of combustion data were derived and analyzed using a double Wiebe's function approximation using two laboratory engines, one direct injection and one indirect injection, were operated for a range of speeds, loads, injection timings, fuels, and steady and transient conditions.
Abstract: Two laboratory engines, one direct injection and one indirect injection, were operated for a range of speeds, loads, injection timings, fuels, and steady and transient conditions. Rate of combustion data were derived and analyzed using a double Wiebe's function approximation. It is shown that three of the six function parameters are constant for a wide range of conditions and that the other three can be expressed as linear functions of the amount of fuel injected during ignition lag. Engine noise, smoke, and thermal efficiency correlate with the parameters describing the amount of premixed combustion and diffusive combustion duration. These characteristics may be optimized by reducing the quantity of premixed combustion while maintaining the duration of diffusive combustion to less than 60 /sup 0/CA.

141 citations


Patent
Yoshiki Noguchi1, Tadao Arakawa1, Nobuo Nagasaki1, Shigehisa Sugita1, Masato Takeuchi1 
31 Jul 1985
TL;DR: In this paper, a fuel cell power plant is characterized by the provision of another combustor on the passage through which cathode exhaust gas is sent from the cathode to the turbine and a passage for leading a part (112) of the anode exhaust gases to the another combustionor, whereby unburnt gas included in the anodes exhaust gas are burnt with the cathodes supplied as oxygen source so that the temperature of the turbine driving gas is raised, as result, the overall thermal efficiency of the power plant increases.
Abstract: This invention relates to a fuel cell power plant. The power plant comprises a fuel cell (10) employing a molten carbonate as an electrolyte, a reformer (24) for reforming fuel into a reactive gas to be.supplied into the anode (14) of the cell (10), an expansion turbine (84) connected to a compressor (36), a combustor (62) for burning a gas exhausted from the anode (14) and introducing the combustion gas into the cathode (16) of the fuel cell (10) along with a gas compressed by the compressor (36), and a waste heat recovery system (92). The power plant is characterized by the provision of another combustor (110) on the passage through which cathode exhaust gas (76) is sent from the cathode to the turbine and a passage for leading a part (112) of the anode exhaust gas to the another combustor, whereby unburnt gas included in the anode exhaust gas is burnt with the cathode exhaust gas supplied as oxygen source so that the temperature of the turbine driving gas is raised, as a result, the overall thermal efficiency of the power plant increases (Fig. 1).

116 citations


Patent
25 Feb 1985
TL;DR: In this paper, a gas turbine engine comprising a compression means, combustion means, a first turbine, and a second turbine is provided with improved thermal efficiency and power output through bypassing a portion of the engine operating fluid from a first engine position downstream of at least a portion the compression means and upstream of a control area of the first turbine.
Abstract: A gas turbine engine comprising a compression means, combustion means, a first turbine, and a second turbine is provided with improved thermal efficiency and power output through bypassing a portion of the engine operating fluid from a first engine position downstream of at least a portion of the compression means and upstream of a control area of the first turbine and injecting at least a portion of the bypassed flow downstream of the control area of the first turbine. High pressure steam is injected at a position between the engine position initiating the bypass and the engine position injecting the bypass into the fluid stream. The amount of steam injected is substantially equivalent in mass flow to the removed fluid.

59 citations


Patent
12 Mar 1985
TL;DR: In this paper, an internal combustion steam engine is operated with an alcohol-water fuel mixture vaporized prior to combustion by heated engine coolant that flows through a first heat exchanger.
Abstract: An internal combustion steam engine is operated with an alcohol-water fuel mixture vaporized prior to combustion by heated engine coolant that flows through a first heat exchanger. The first heat exchanger or vapor generator uses the waste heat from the engine coolant to heat and vaporize the alcohol-water mixture. A second heat exchanger using exhaust gases heats the combustion air before passage through the intake manifold. Complete vaporization of the alcohol fuel is accomplished to overcome the lower caloric power potential of alcohol as compared to gasoline and to insure complete and regular combustion.

50 citations


Patent
04 Feb 1985
TL;DR: A vehicle power system including an auxiliary engine in combination with the main vehicle engine with the auxiliary engine providing auxiliary electrical energy for the vehicle electrical system and a source of thermal energy for heating the vehicle operating compartment.
Abstract: A vehicle power system including an auxiliary engine in combination with the main vehicle engine with the auxiliary engine providing auxiliary electrical energy for the main vehicle electrical system and a source of thermal energy for heating the vehicle operating compartment.

47 citations


Patent
14 Mar 1985
TL;DR: In this article, an electrical generating plant of high efficiency utilizes a conventional steam plant powered by coal, gas or oil, in internal integration with a high temperature solid-oxide fuel-cell.
Abstract: An electrical generating plant of high efficiency utilizes a conventional steam plant powered by a fossil fuel such as coal, gas or oil, in internal integration with a high temperature solid-oxide fuel-cell. In one embodiment, the spent fuel and the wast heat from the fuel-cell of electrochemical action is made directly available to the combustion furnace of the steam plant for thermodynamic extraction. The system can achieve efficiencies up to 65% compared to ordinary steam plants which have an efficiency of about 35%.

47 citations


Patent
17 Dec 1985
TL;DR: In this paper, the authors described an approach for treating liquid fuels to include precious metal catalysts dispersed within a liquid which is dispersed within the fuels, and the liquid is treated prior to introduction into a combustion chamber for combustion.
Abstract: Apparatus and processes are disclosed for treating liquid fuels to include precious metal catalysts dispersed within a liquid which is dispersed within the fuels The precious metal catalysts are preferably present at a level of from about 0005 to 05 ppm by weight of the treated fuel, and the liquid is preferably present at a level of from about 3 to about 15% by volume of the fuel The fuel is treated prior to introduction into a chamber for combustion

44 citations


Patent
02 Jan 1985
TL;DR: The most stable near-laminar flow in a cylinder is an axial vortex because of symmetry, and hence the induction port design should establish an Axial vortex and a low velocity.
Abstract: Adiabatic positive displacement gas cycle machinery is designed with explicit control of the heat flow between the gas and the walls. The control is achieved by maintaining near-laminar flow and a small wall area to volume ratio. The most stable near-laminar flow in a cylinder is an axial vortex because of symmetry, and hence the induction port design should establish an axial vortex and a low velocity. Induction and exhaust port designs to achieve this flow are applied to a vane pump, an adiabatic air compressor, a diesel engine, and two and four stroke Otto cycle engines. The gain in thermal efficiency for these designs can be significant, up to a factor of 2, since the largest inefficiency in nearly all positive displacement machinery is imperfect control of heat flow.

43 citations


Patent
10 Jun 1985
TL;DR: In this paper, a combustion control method for a boiler is proposed, where manipulated variables or the amounts of fuel and air in at least one combustion zone of a boiler are regulated so that both the amount of nitrogen oxides and the unburned coal in the ash at an outlet of a burner furnace pass the regulation standards and satisfies the requirements for operating a plant.
Abstract: A combustion control method wherein manipulated variables or the amounts of fuel and air in at least one combustion zone of a boiler are regulated so that both the amount of nitrogen oxides and the amount of unburned coal in the ash at an outlet of a burner furnace or at least one of them passes the regulation standards and satisfies the requirements for operating a plant. The method is characterized by varying the amounts of fuel and air in performing trial operations on manipulated variables to evaluate the nitrogen oxides at the furnace outlet, the unburned coal in the ash at the furnace outlet and the stability of combustion, and declaring as optimum manipulated variables those amounts of fuel and air used for performing the trial operations which achieve results such that the combustion is found to be stabilized, at least the nitrogen oxides at the furnace outlet satisfy the requirement and the thermal efficiency of the boiler is judged to be at the highest level by a boiler thermal efficiency judging section.

Journal ArticleDOI
TL;DR: In this article, the operation of a photovoltaic solar cell is discussed with a quantum two-level system as a model and a detailed balance calculation is carried out, from which the parameters of the converter, illuminated by radiation from a black body, are exactly obtained in different geometries, taking into account radiative recombination processes.
Abstract: The operation of a photovoltaic solar cell is discussed with a quantum two‐level system as a model. A detailed‐balance calculation is carried out, from which the parameters of the converter, illuminated by radiation from a black body, are exactly obtained in different geometries, taking into account radiative recombination processes. It is shown that in a 4π geometry (source fully surrounding the converter) with total radiative recombination, the thermodynamic efficiency is equal to the Carnot efficiency at zero current (open circuit): the converter behaves as an ideal thermal engine, fully reversible when delivering no power (the practical efficiency is evidently zero). The reversibility is ensured by the complete exchange of photons between the source and the converter. The current‐voltage relation is obtained in all cases, and it is shown that the two‐level system follows the ideal diode equation. The calculation of the thermodynamic efficiency is generalized to an energy band system (real semiconductor) with radiative recombination and is shown to be maximum at open circuit, but lower than the Carnot efficiency because of irreversibilities induced by the thermalization of carriers. The effective source temperature concept is discussed. It is shown to be valid for a two‐level system, but has less physical meaning for a two‐band system.

PatentDOI
TL;DR: In this paper, a single appliance is divided into four sections: a lower water storage section, a middle hardware section, an upper internal air handling section, and a side external air handling area protruding through a building wall.
Abstract: Space heating and cooling and potable water heating are provided by a single appliance. The housing appliance is divided into four sections: a lower water storage section, a middle hardware section, an upper internal air handling section and a side external air handling section which may protrude through a building wall. A heating medium from a single burner heat exchanger may be directed to either a liquid to air heat exchanger for space heating or to a hot water storage tank for heating potable water. The storage tank contains a heat exchanger for heat transfer from the heating medium to the potable water. A single thermostatic flow control maintains a constant temperature of heating medium directed to either the liquid to air heat exchanger or the storage tank to provide condensation of products of combustion during the space heating mode of operation and part of the water heating mode of operation and yet preclude overheating of the heating medium. As a result of the thermostatic flow control, a low flow rate for higher efficiency is feasible and the flow rate may be varied with changes in the temperature of the stored water. For added efficiency, refrigerant from the air conditioner compressor may pass in heat exchange relationship with the stored water to recover heat of compression by the stored water.

Journal ArticleDOI
TL;DR: In this article, a reciprocating heat engine with nonlinear coupling of the working fluid to an external light source was examined and the piston trajectories that optimize two different criteria of process performance, the maximization of work output, and the minimization of entropy production were determined.
Abstract: We examine a reciprocating heat engine which necessarily operates far from equilibrium and about an unstable steady state. The piston of the engine is driven by the nonlinear coupling of the working fluid to an external light source which provides high quality heat and to the environment into which waste heat is dumped. We determine the piston trajectories that optimize two different criteria of process performance, the maximization of work output, and the minimization of entropy production. The trajectories optimizing different performance goals are qualitatively different. In engines not dominated by friction losses, the cycle optimizing work output requires that the expansion stroke begins with a slight compression and the temperature of the working fluid increases briefly.

Patent
10 May 1985
TL;DR: In this paper, a new venturi-based mixing device for the air-fuel-EGR is disclosed, placed upstream of the main throttle valve, which is also applicable to diesel-gas, and straight diesel engines, with or without pressure charging.
Abstract: In a spark-ignited gas engine with relatively high compression ratio of approximately e=12, operation takes place with relatively poor mixtures with air/fuel ratios of about λ=1.6 or over in order to reduce NOx production. At loads about approximately 70% of the (normally aspirated) nominal power, the oxygen-ratio must be reduced in order to aspirate sufficient fuel for the power demand. NOx-production would steeply rise, but according to the invention exhaust gas (EGR) is recirculated at least up to nominal load, in order to maintain complete combustion at λ=1.0 and meanwhile keep NO.-production low. A X-sensor in the exhaust gases may be used for that purpose. A new venturi-based mixing device (4) for the air-fuel-EGR is disclosed, placed upstream of the main throttle valve (2). The system is also applicable to diesel-gas, and straight diesel engines, with or without pressure charging. Due to the high compression ratio, thermal efficiency remains high.

Patent
21 Oct 1985
TL;DR: In this paper, a gas turbine including at least a compressor, a combustor, and a turbine is constructed to operate at a preferred thermal efficiency in predetermined compressor and turbine flow pressure ratios.
Abstract: A gas turbine including at least a compressor, a combustor, and a turbine is constructed to operate at a preferred thermal efficiency in predetermined compressor and turbine flow pressure ratios. A fluid, such as steam, for example produced by waste heat and pressurized as water, and characterized as having a higher specific heat at constant pressure than effluent from the combustor is introduced into such effluent to provide a turbine operating medium of improved potential to transfer energy downstream of the combustor. Such injection provides effective variable geometry to the system. This injection system maintains such pressure flow ratios substantially independent of engine power output.

01 Jul 1985
TL;DR: In this article, three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced adiabatic diesel engines for heavy-duty trucks operating in linehaul service.
Abstract: Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced adiabatic diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum imporvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.

Journal ArticleDOI
TL;DR: In this article, the exergy delivery of flat-plate solar collectors is investigated in terms of exergy deliver of the collector and various exergy efficiencies are defined and output exergy efficiency is used to determine the optimum flow rate of a typical collector allowing for the pressure drop in tubes.

Patent
08 Oct 1985
TL;DR: In this paper, a reverse humidification in a multistage reverse humidifier in place of part or all of the dilute hot air containing water vapor, only the water temperature below the boiling point is used.
Abstract: This process discloses a gas turbine the chemical energy contained in the fuel to produce mechanical or electrical energy, in order to drive the gas turbine, the compressed air for combustion of the fuel prior to combustion in a multistage reverse humidification in the humidifier in place of part or all of the dilute hot air containing water vapor, only the water temperature below the boiling point, the effectiveness of the humidification only work under pressure, before the humidified air through a heat exchange between the cooling water humidified each other, compare combined cycle, steam injected cycle and intercooled regenerative cycle, this process has greatly improved thermal efficiency, in addition to all of the steam cycle of the combined cycle equipment can be omitted.

Journal ArticleDOI
TL;DR: In this article, the performances of a hydrogen-fueled gas turbine cycle equipped with an intercooler, regenerator, hydrogen turbine and recuperative hydrogen heater are analyzed.

Proceedings ArticleDOI
TL;DR: In this paper, the authors investigated the effects of in-cylinder flow on spray and combustion, and the existence of optimum values of these parameters against thermal efficiency have been predicted and these predictions have been verified by measurement.
Abstract: The study of the phenomena of in-cylinder flow, spray and combustion by measurement and calculation has been vigorously pursued, because thermal efficiency and emissions of the D.I. diesel engine are influenced by them. To investigate the effects of in-cylinder flow on spray and combustion, the D.I. diesel engine simulation model has been developed. This model is composed of in-cylinder flow, spray and combustion models. In the spray model, spray non-uniformity is considered, and physical and chemical processes are considered in the combustion model. The effects of swirl, number of nozzle holes, injection pressure and squish area on thermal efficiency and emissions have been investigated, and the existence of optimum values of these parameters against thermal efficiency have been predicted and these predictions have been verified by measurement.

Patent
Takao Ishihara1
22 Feb 1985
TL;DR: In this article, a coal-melting combustion furnace is used to remove coal ash in a molten state and then the dust is removed from the combustion gas by a cyclone disposed in the combustion furnace.
Abstract: In a coal-fired combined plant, finely powdered coal is burned at high temperature in a pressurized coal-melting combustion furnace to obtain combustion gas substantially free of dust to drive a gas turbine in order to generate electric power. Waste gas from the gas turbine is used to produce steam which drives a steam turbine for additional electric power generation. Primary dust removal from the combustion gas is carried out by removing most of the resulting coal ash in a molten state. In a secondary dust removal, the dust is removed from the combustion gas by a cyclone disposed in the combustion furnace. In a tertiary dust removal, the dust is removed from the combustion gas which is discharged through an outlet at the combustion furnace by a precision dust-removing device.

Proceedings ArticleDOI
TL;DR: In this paper, a theoretical analysis of the VR/LE engine with variable crank-radius to connecting-rod-length ratio R/L has been performed with the help of the thermodynamic type model (zero-dimensional) including NO formation submodel.
Abstract: A theoretical analysis of the spark ignition VR/LE engine with the variable crank-radius to connecting-rod-length ratio R/L has been performed with the help of the thermodynamic-type model (zero-dimensional) including NO formation submodel. The analysis has made it possible to determine the changes of some basic output engine parameters: thermal efficiency, work and NO concentration, as a result of the engine thermodynamic cycle variations. A comparison between the VR/LE and conventional engines is presented. The ranges of the phase angle which can give the gain in efficiency and NO emission reduction are also determined. The analysis has confirmed that the VR/LE engine concept has remarkable economy potential with application to the SI engines and it is worth performing a research with an actual engine.

Patent
16 Oct 1985
TL;DR: In this paper, a method and apparatus for operating an internal combustion engine that substantially improves the fuel efficiency by utilizing heat normally discharged to the ambient to condition and prepare the fuel mixture prior to its entry into the combustion chambers is presented.
Abstract: A method and apparatus for operating an internal combustion engine that substantially improves the fuel efficiency by utilizing heat normally discharged to the ambient to condition and prepare the fuel mixture prior to entry into the combustion chambers. The apparatus com­ prises a fuel vaporizer, a fuel mixture heater and a mixture homogenizer located in a fuel mixture flow path intermediate the vaporizer and the heater. The fuel vaporizer includes structure defining an inner heat exchange chamber which receives air and entrained fuel discharged by a fuel introduc­ ing device such as a carburetor. The fuel mixture is heated and at least partially vaporized by engine waste heat derived from the engine cooling system or alternately the engine exhaust system. To facilitate the transfer of heat to the fuel mixture, a pair of heat exchange members are disposed in the chamber and include a supply tube defining a flow path for fluid carrying engine waste heat and a plurality of bristle-like heat exchange surfaces radiating outwardly from the supply tube. The bristle-like surfaces are located in heat exchange relation with the fuel mixture in the vaporizing chamber and transfer heat from the heat exchange fluid to the fuel mixture as the fuel mixture passes through the vaporizer.


Journal ArticleDOI
TL;DR: In this paper, a general form of availability efficiency, efficiency of a process based on the available energy analysis, is reduced to suitable forms for equipment like a heat exchanger, separator, heat engine, furnace, coal gasifier, turbine, compressor, heat pump and refrigerator.

10 Nov 1985
TL;DR: In this paper, the problem of optimal control of thermodynamic processes of heat and mass transfer on contact of two systems was considered, where the control signal is a vector of the temperatures and concentrations of one system, the parameters of the second being variable at a rate proportional to the heat and material flows.
Abstract: This paper considers problems of optimal control of thermodynamic processes of heat and mass transfer on contact of two systems. The control signal is a vector of the temperatures and concentrations of one system, the parameters of the second being variable at a rate proportional to the heat and material flows. The limiting efficiency of the heat machine is found when the cycle duration and source capacities are bounded.

Patent
21 Nov 1985
TL;DR: In this paper, a method and a device for obtaining heat energy, which can be converted into mechanical energy, from the combustion or incineration process of wet waste in a combustion power plant is presented.
Abstract: The invention relates to a method and a device for obtaining heat energy, which can be converted into mechanical energy, from the combustion or incineration process of wet waste in a combustion power plant. … The invention proceeds from the fact that most of the moisture contained in wet waste has to be removed before the latter is delivered to a combustion power plant for combustion. To this end, two heat sources are used, one of which is used for the (water) vapour of the waste itself, which vapour is generated during the drying process, there being a thermal compression (or compression) and a return to the dryer taking place. This acts as the main heat source for drying the wet waste, while the other generates (water) vapour which is generated by the use of solar energy. With this method, the loss of heat energy from the combustion of wet waste can be reduced to a great extent; the combustion conditions for the combustion material can be improved; the combustion gas temperature can be increased considerably. … It is also possible to add a drying stage by means of high-temperature combustion gases, so that the combustion temperature is increased and the combustion conditions of the fuel in the waste are improved. ... … Original abstract incomplete.

Patent
04 Mar 1985
TL;DR: In this article, a two-stage tunnel furnace is proposed to improve thermal efficiency by recovering heat from the upper heat absorbing medium in which a red hot slab passes by means of a heat exchanger, reheating the media by hot air passing through the lower stage and feeding the same into the upper stage.
Abstract: PURPOSE:To improve thermal efficiency by recovering heat from the upper heat absorbing medium in a two-stage tunnel furnace in which a red hot slab passes by means of a heat exchanger, reheating the media by the hot air passing through the lower stage and feeding the same into the upper stage. CONSTITUTION:A red hot slab 3 emitted from a continuous casting machine is fed by roller tables 1 into an upper and lower two-stage type tunnel furnace 4. The heat medium in the upper chamber 5 having many fins 8 is heated and enters the 1st heat exchanger, by which heat is recoverd from the medium. The medium emitted from the heat exchanger 9 enters the 2nd heat exchanger 1 and is reheated by the blowing air 21 heated in a lower chamber 6. The heated medium enters again the upper chamber 5. The need for cooling the rollers 1 by blowing of cold air 21 from below is eliminated. Less heat insulating materials are required by the double wall construction of the furnace 4 and the efficiency in recovering heat is improved by two stages of heat recovery.

Patent
04 Feb 1985
TL;DR: In this paper, the authors proposed to improve the thermal efficiency of steam turbine power plant by arranging such that a leaked steam from the power plant is guided into a vortex tube and has its eneregy separated so that the heat of high temperature steam was recovered as a part of heating steam and a low temperature steam is reused as a cooling steam.
Abstract: PURPOSE:To improve the thermal efficiency of steam turbine power plant, by arranging such that a leaked steam from the power plant is guided into a vortex tube and has its eneregy separated so that the heat of high temperature steam is recovered as a part of heating steam and a low temperature steam is reused as a cooling steam CONSTITUTION:Introduced into vortex tubes 55-57 are, a leaked steam 58 from the valve spindle of steam adjusting valve 28 provided at the inlet of super high pressure turbine 2 in a super ultra critial pressure power plant and leaked steams 61, 64 from respective turbine shaft sealed areas 29a, 29b of high and low pressure sides of ultra high pressure turbine 2 Leaked steams are separated into high temperature steams 59, 62, 65 and low temperature ones 60, 63, 66 through respective vortex tubes 55-57, the former steams 59, 62, 65 being guided into feed water heaters 21, 20, 19 respectively On the other hand, low temperature steams 60, 63 are guided into the stage of turbine 2 as its internal cooling steam and remaining steam 66 is guided into the stage lower in pressure than that of turbine 2 as its internal cooling steam