Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K21/00—Steam engine plants not otherwise provided for
  • F01K21/04—Steam engine plants not otherwise provided for using mixtures of steam and gas; Plants generating or heating steam by bringing water or steam into direct contact with hot gas
  • F01K21/042—Steam engine plants not otherwise provided for using mixtures of steam and gas; Plants generating or heating steam by bringing water or steam into direct contact with hot gas pure steam being expanded in a motor somewhere in the plant
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K19/00—Regenerating or otherwise treating steam exhausted from steam engine plant
  • F01K19/02—Regenerating by compression
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K19/00—Regenerating or otherwise treating steam exhausted from steam engine plant
  • F01K19/02—Regenerating by compression
  • F01K19/04—Regenerating by compression in combination with cooling or heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
  • F01K25/06—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using mixtures of different fluids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E20/00—Combustion technologies with mitigation potential
  • Y02E20/16—Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Definitions

• the invention relates to a method for converting thermal energy into mechanical energy in a heat engine in which the thermal efficiency of the heat engine is increased without the upper and / or the lower cycle temperature having to be changed.
• the invention also relates to a heat engine for performing this method.
• the thermal efficiency of the cycle of such a machine is the ratio between the shaft work achieved and the thermal primary energy used. It grows with the height of the difference between the upper and the lower process temperature and can at most reach the value of an ideal Carnot machine.
• the maximum achievable thermal efficiency of the cycle results from Carnot's theorem:
• T 0 is the upper process temperature
• T u is the lower process temperature.
• a heat engine In order to achieve the highest possible yield of shaft work or kinetic energy per unit of thermal primary energy used, a heat engine must have the highest possible thermal efficiency. This goal can be achieved by increasing the efficiency of the cycle. For this, according to Carnot's theorem, either lowering the lower process temperature and / or increasing the upper process temperature is required. The increase in the upper process temperature is limited due to the temperature resistance of the materials used in a heat engine.
• Another method for increasing the efficiency of heat engines is to reduce the exergy losses when absorbing and dissipating thermal energy by making the most of the available temperature difference between absorbed and emitted heat in a chain of cycle processes.
• two or more machines are connected in series, the waste heat from an upstream cycle process being used as heat from a subsequent cycle process.
• This process is used, for example, in modern combined cycle power plants (combined cycle power plants), in which the high temperature of a combustion process is first used in a gas turbine, the exhaust gas of which is then also used to heat a steam power plant. In this way, the exergy loss in steam generation is reduced and the temperature gradient between the combustion and ambient temperature is used in several stages.
• a disadvantage of the serial coupling of circular processes is the additional outlay in terms of equipment for heat transfer and energy conversion per circular process. Furthermore, the exergy losses of the energy conversion increase with the number of serially coupled cycle processes, since the heat transfer by means of a heat exchanger is only possible if a finite temperature difference is maintained. Another disadvantage is that the waste heat from the last cycle in the serial chain still has to be dissipated to the environment.
• the present invention is therefore based on the object of providing a method in which the thermal efficiency of a heat engine can be increased without having to change the upper and / or the lower process temperature of the thermal cycle. It is also an object of the invention to provide a heat engine for performing this method.
• the thermal efficiency of the cycle is defined by the ratio of work done to the thermal energy used, per cycle of the cycle.
• the thermal efficiency of a heat engine is defined by the ratio of work done to the thermal energy used, and is summed up over all cycles of the cycle.
• the efficiency of a heat engine is greater than the efficiency of its associated cycle if the waste heat from its cycle can be used in whole or in part as primary energy within the machine (waste heat recycling). In this case, the energy contained in the waste heat of the cycle does not need to be replaced or only partially replaced by new primary energy, and the cumulative efficiency of the machine increases with the number of cycles completed.
• Figure 2 shows the same process for a cyclic process with a very poor efficiency of only 5%. Even for such a poor process efficiency, the efficiency of the heat engine can be increased very widely over the number of cycles. With sufficiently efficient waste heat recirculation, such a heat engine can be operated economically when using low-temperature heat.
• the waste heat recirculation is limited in that the waste heat temperature is significantly lower than the required temperature of the heat to be supplied to the cycle. Therefore, only a small part of the energy contained in the waste heat can be returned to the cycle. Raising the temperature level of the waste heat to the upper process temperature would require a heat pump in conventional machines so that the energy of the waste heat could be returned to the cycle. This heat pump would consume part of the shaft work generated by the first machine. As a result, the waste heat return for conventional heat engines according to the state of the art is only economically possible to a limited extent.
• the method according to the invention now increases the cumulative thermal efficiency of heat engines by internal waste heat recirculation without consuming shaft work for a conventional heat pump process.
• the heat engine according to the invention has one steam and one gas cycle process within a heat engine, that is, two simultaneous cycle processes which are 'entangled' or superimposed on one another in the gas phase.
• the steam cycle process is used to generate wave work.
• the steam cycle process draws its heat from an external heat source, the waste heat from the steam cycle being the heat for the coupled gas cycle process.
• the working medium A in the steam cycle process is a substance or mixture of substances whose components have a significantly higher molecular dipole moment than a component B of the working medium AB in the gas cycle process, which is essentially permanently in a gaseous state.
• working medium A undergoes a cyclical phase change between liquid and gas, and to a large extent like in a conventional steam engine or steam turbine.
• the gas cycle process serves to recycle waste heat within the heat engine according to the invention.
• the waste heat contained in the relaxed working medium A of the steam cycle process is materially supplied to the gas cycle process as heat for generating wave work.
• the gas cycle process also converts part of the waste heat from the steam cycle into wave work.
• Component B is a substance or a mixture of substances whose constituents have a significantly lower molecular dipole moment than the constituents of working medium A from the steam cycle process.
• the working medium AB is regularly supplied with a gaseous amount of the working medium A from the steam cycle process and withdrawn again in liquid form.
• the percentage of A within AB changes periodically over a closed cycle of the gas cycle process.
• the material entanglement of both cycle processes in the gas phase serves the direct exchange of heat energy between the substances or substance mixtures A and AB of the two cycle processes and the condensation of the working medium A.
• the exchange of heat energy takes place using Brown's see molecular movement through elastic collisions between gas molecules the substances of both working media (number of impacts on the order of 10 per second).
• the kinetic energy of the molecules (which is equivalent to temperature) is subject to a statistical probability distribution according to Maxwell's theory.
• Maxwell's theory it should be noted that the atoms or molecules of a gas or in a liquid move continuously and constantly collide with one another. Due to the impact processes, they constantly change their direction of movement, their energy and thus also their speed.
• the velocity in a gas or in a liquid is therefore not the same for all atoms or molecules, but follows Maxwell's velocity distribution.
• E 3 kT / 2.
• there is not just one temperature in the gas phase but a range of temperatures that is equivalent to the statistical distribution of molecular velocities.
• the chaotic movement of the Molecules from material groups A and B in the gas phase produce elastic collisions between molecules with different velocities and dipole moments.
• a phase transition of the working medium A occurs due to a spontaneous formation of fog from the mixture AB in the gas cycle process of the heat engine according to the invention.
• the drops of this mist can then be removed from the gas phase of the gas cycle process by means of a phase separation using conservative force fields (for example gravity or centrifugal field) and fed back to the steam cycle process via a feed water pump.
• a stream of working medium A in the gaseous phase is thus supplied to the gas cycle process and withdrawn again in the liquid phase.
• the heat supplied to the gas cycle process is the latent heat contained in the supplied gaseous fraction A, which corresponds to the heat of condensation.
• the heat transfer from the steam cycle process to the gas cycle process takes place through condensation of the working medium A in the gas cycle process.
• the waste heat from the gas cycle process is the heat dissipated with the liquid phase of working medium A.
• the difference between supplied and removed heat is the heat of condensation of the material flow of the quantity of working medium A exchanged between the steam cycle process and the gas cycle process. It corresponds to the maximum wave work that can be generated in the gas cycle process.
• the heat of condensation of the steam cycle process of the heat engine according to the invention can thus be process (minus any radiated heat) can be completely converted into wave work. With the exception of the radiated heat, the heat engine according to the invention therefore has no further waste heat.
• the efficiency of a heat engine according to the invention is thus increased over the number of cycle cycles, even if the steam cycle efficiency is poor. It follows that the heat engine according to the invention is also suitable as an energy converter for the use of low-temperature heat.
• FIG. 2 shows the efficiency of a heat engine accumulated over 200 cycles with an initial efficiency of 5%
• FIG. 3 shows the pV diagram of a steam cycle process which is coupled with a gas cycle process according to the invention
• FIG. 4 shows the energy flows between the circular processes of the heat engine according to the invention
• FIG. 5 shows the Maxwell distribution and the fog condensation of the two working media A and AB
• FIG. 6 shows a detailed illustration of the individual functional modules of the heat engine according to the invention.
• Figure 7 is an illustration of the function blocks of a compact heat engine according to the invention.
• FIG. 1 shows various courses of the efficiencies of a hypothetical heat engine over 20 cycles.
• the cycle process of the heat engine has a thermal efficiency of 35%.
• the heat engine has the same efficiency as long as no waste heat is returned to the cycle (course at 0%). If the waste heat that is emitted by it is fed back to the cycle to a certain extent over several cycles, the efficiency of the heat engine slowly increases. With waste heat recirculation of 80%, for example, the heat engine shown achieves an efficiency of about 70% after 20 cycles.
• FIG. 2 shows the same process for a cyclic process with an efficiency of only 5%.
• the efficiency of the heat engine increases from 80% to a value of approximately 20% with waste heat recirculation. With the help of waste heat recirculation, the efficiency of the heat engine could be roughly quadrupled compared to the efficiency of the cycle.
• a steam cycle process left pV diagram
• a gas cycle process right pV diagram
• a simple process without multiple reheating is shown here as a steam cycle process.
• the method can also be applied to all other steam cycle processes.
• the steam cycle process contains six excellent points Dl to D6.
• the gas cycle process contains four excellent points G1 to G4. The individual steps are explained in detail below:
• the liquid of the steam cycle is pumped from low to high pressure and fed to an evaporator at high pressure.
• D2-D3 Working medium A is evaporated in the evaporator at high pressure with the addition of heat (Q zu ) and converted from the liquid to the gaseous phase.
• D5-D6 In a conventional steam cycle process, this section would be the complete expansion of the steam down to the wet steam area. In the machine according to the invention, however, this process takes place in the gas cycle process.
• D6-D1 In the case of a conventional steam cycle process, this section would be the transfer of the steam cycle process medium A from the gaseous to the liquid phase, in that the condensation is forced by means of heat removal.
• the hatched area Q ab corresponds to the waste heat from the steam cycle. In the method according to the invention, this process also takes place in the gas cycle process.
• G1-G2 Adiabatic compression of the gas process working medium AB.
• the pressure and temperature of the medium AB rise and its relative humidity with respect to the component A decreases.
• a quantity of substance of the medium A from the steam cycle process is mixed in, as described for the transition D5-G2.
• the gas mixture is expanded adiabatically with the release of wave work.
• the molecules of substance A with a higher dipole moment coagulate into droplets, releasing their kinetic energy to the particles AB remaining in the gas phase.
• Fog is formed under pressure and volume of the remaining amount of residual gas AB.
• the relative humidity of the gas phase AB with respect to substance A increases to 100%.
• the latent heat of condensation of the amount of substance A condensed as mist remains in the residual gas amount AB.
• G4-G1 Decrease in volume due to liquid withdrawal: The mist is removed from the residual gas volume of the working medium AB via a phase separation in the conservative force field (preferably a centrifugal field) and returned to the steam cycle process as a liquid.
• the points G4 and Gl are actually very close together, so that the outline of the gas cycle process in the pV diagram results in almost a triangle.
• the area surrounded by the Dl-2-3-4-5-6-1 line corresponds to the maximum work that can be generated in the steam cycle process.
• the the area surrounded by the line Gl-2-3-4-1 corresponds to the maximum work that can be generated in the gas cycle process.
• the waste heat from the steam cycle process is transferred from the point D5 to point G2 as input heat to the gas cycle process with the exhaust gas from the steam cycle process working medium A, and the waste heat from the gas cycle process is transferred with the condensed liquid from point G4 to point D1 as input heat into the steam cycle process. Both cycle processes produce work and waste heat from the heat supplied.
• the combination of the two cycle processes in a heat engine means that it does not give off any waste heat to the environment.
• FIG. 4 shows the energy flows in the heat engine according to the invention between the steam cycle process and the gas cycle process.
• the machine contains two cyclic processes, each of which generates shaft work (W D and W G ) and waste heat (Q D and Q G ) from the heat supplied.
• the heat Q ⁇ xc ⁇ r ⁇ the steam cycle process . plus Q G , and the heat Q D is supplied to the gas cycle process. Because the two cycle processes mutually reuse their respective waste heat flow as supplied heat, the machine can completely heat the flow Q ⁇ supplied from outside in wave work W axter -. convert (less any radiated heat).
• FIG. 5 shows the Maxwell's velocity distribution of the gaseous mixture of the two working media A and B, where N (u) in each case indicates the number of molecules which have a specific velocity u.
• N (u) in each case indicates the number of molecules which have a specific velocity u.
• a mixture of working media A and B with a reduced concentration of working medium A remains in the gaseous state (top right diagram in FIG. 5).
• the working medium A forms droplets and can be removed from the gas phase, for example with the aid of a centrifuge (lower right diagram in FIG. 5).
• a mass transfer takes place only between the two cycle processes within the machine and not with the environment.
• the machine can be constructed as a closed system, the system limit of which is only for thermal energy and wave work is permeable. Since the machine does not have to return waste heat to the environment, it can use low-temperature thermal energy as a heat source. This requires that the steam cycle process have a phase transition temperature below the temperature of the low-temperature heat source. Otherwise, the low temperature heat cannot be used to evaporate the steam cycle working medium. Since the radiation losses are low when the thermal energy is supplied at a low temperature, the efficiency of the machine is even better when using low-temperature heat than when using high-temperature heat.
• the heat engine according to the invention can be designed as a piston machine (motor) or as a turbo machine (turbine). Since a centrifugal field is advantageous for phase separation of the mist, a turbomachine is preferably used, since such a centrifugal field can easily be generated in the rotating parts of a turbine.
• FIG. 6 shows an extensive system which is suitable for a steam cycle process with overheating
• FIG. 7 shows a compact system which, as a minimal configuration, only contains the absolutely necessary system elements.
• Heat engine at least the functional components: pump, evaporator, steam turbine, mixing chamber, gas turbine, condenser,
• the steam cycle contains the building blocks: pump, evaporator, steam turbine and condenser.
• the gas cycle process contains the building blocks: gas turbine and compressor.
• the mass transfer between the two cycle processes takes place by means of a mixing chamber and a centrifuge.
• the shaft work consumers are the compressor, pump and centrifuge, which are driven by the gas and / or steam turbine.
• the steam and / or gas turbine deliver wave work to an external consumer.
• Liquid working medium A is fed to the evaporator via the pump, evaporated at high pressure with the addition of heat and expanded in the steam turbine with the emission of wave work.
• the exhaust gas from the steam turbine is mixed in the mixing chamber with the working gas AB compressed by the compressor in the gas cycle process and expanded via the gas turbine, releasing wave work.
• mist is created in the condenser. The mist is removed from the gas phase of the gas cycle process in the centrifuge and fed back into the vapor cycle process as a liquid via the pump.
• the steam and gas turbine function blocks and the mixing chamber in the turbine module and the condenser and centrifuge function blocks are combined in the condensation centrifuge module.
• the gas streams of both cycle processes are brought together directly in a turbine, the exhaust gas of which is separated into the two phases in the condensation centrifuge.
• the pump and compressor return the respective fluids back into the circuit.
• Such a unit can be built very compact.
• the heat engine according to the invention can be used both in the high-temperature range and in the low-temperature range, provided that the phase transition temperature of the steam cycle is below the temperature of the heat source. Since the heat engine does not require a mass transfer with the system environment, it is completely environmentally neutral. in the Materials that cannot be used in the high temperature range due to a lack of heat resistance can be used in the low temperature range.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Engine Equipment That Uses Special Cycles (AREA)

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• 1997
  • 1997-11-17 DE DE19750589A patent/DE19750589C2/de not_active Expired - Fee Related
• 1998
  • 1998-11-04 WO PCT/EP1998/006933 patent/WO1999025955A1/de not_active Application Discontinuation
  • 1998-11-04 IL IL13603398A patent/IL136033A0/xx unknown
  • 1998-11-04 ID IDW20001169A patent/ID27051A/id unknown
  • 1998-11-04 AU AU16655/99A patent/AU1665599A/en not_active Abandoned
  • 1998-11-04 BR BR9812786-1A patent/BR9812786A/pt not_active Application Discontinuation
  • 1998-11-04 JP JP2000521301A patent/JP2001523786A/ja not_active Withdrawn
  • 1998-11-04 CN CN98811127.6A patent/CN1278890A/zh active Pending
  • 1998-11-04 EP EP98961120A patent/EP1032750A1/de not_active Withdrawn
  • 1998-11-16 TW TW087118937A patent/TW394814B/zh not_active IP Right Cessation

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