DE102014206474A1 - Plant for providing heat energy for heat consumers - Google Patents

Abstract

A system (10) for providing thermal energy for heat consumers contains an internal combustion engine (12) which is arranged in a substantially closed housing (34) which has an inlet opening (36) for the entry of one part as process air and another Part of the intake air acting as scavenging air and an outlet opening (38) for the exit of the part of the housing (34) having the intake air that acts as scavenging air. The internal combustion engine (12) has an output unit, in particular an output shaft (20) for providing mechanical energy and has an exhaust gas unit (50) for providing thermal energy with a flue gas flow at a first temperature level T1. According to the invention, the heat pump unit (56) is functionally coupled to the internal combustion engine (12) for providing thermal energy at a further temperature level T2, which is preferably different from the first temperature level T1.

Description

The invention relates to a system for providing heat energy for heat consumer, with an internal combustion engine having an output unit, in particular an output shaft for providing mechanical energy and having an exhaust unit for providing heat energy at a first temperature level with an exhaust stream.

Such systems are known as so-called combined heat and power units. For electric power generation, these systems include an electric generator driven by the internal combustion engine. These systems can z. This can be used, for example, to provide decentralized multi-family houses, industrial plants and public buildings with electricity. With the waste heat generated during power generation from the exhaust gas of the internal combustion engine then z. B. hot water treatment systems and / or heating devices operated. In addition, exhaust gas of a gas turbine, in particular in connection with combustion of fossil or organic energy carriers for heat generation, is also referred to as "flue gas", without wishing to make a specific determination with regard to the quality or composition of the exhaust gas.

The object of the invention is to provide a plant for converting energy for combined heat and power, with which by burning a fuel electrical energy and useful heat can be provided decentralized with a maximized fuel efficiency. A preferred object of the invention is to provide a plant for converting energy for combined heat and power, which can provide useful heat in at least two Nutzwärmeströmen different temperature levels.

In the present case, the fuel efficiency of a plant is understood to be the ratio of the electrical energy and thermal energy which can be supplied by the plant for use to the fuel energy used for this purpose.

This object is achieved by a plant of the type mentioned, which contains a heat pump unit for the provision of heat energy at a preferably different from the first temperature level second, further temperature level, which is coupled with the internal combustion engine effect.

The invention is based on the idea that the fuel efficiency of a plant for providing heat for heat consumers can be increased by using the mechanical energy generated by the internal combustion engine, one or more heat pumps are operated to those resulting from the operation of the internal combustion engine To make waste heat usable for heat consumers, preferably at several different temperature levels. Due to the preferred provision of heat energy at at least two different temperature levels, the plant according to the invention can be used particularly well for simultaneously optimizing the fuel efficiency of at least two consumer installations from the fields of refrigerators, hot water treatment systems, steam generator systems and / or heating systems.

In the present case, an internal combustion engine is understood as meaning a heat engine which performs mechanical work by combustion of fuel. In this case, chemical energy from a fuel-air mixture via the temperature of the working gas in pressure or force and expansion, d. H. converted into mechanical energy.

The internal combustion engine can according to the invention z. B. be designed as a diesel engine, gasoline engine, Wankel engine, Stirling engine or as a turbine system.

In this context, a fuel is understood in particular to mean a substance or a substance mixture which, under the supply of an oxidizing agent, in particular air, undergoes an exothermic oxidation reaction with the oxidizing agent, at least after an initial initiation, producing a waste gas or flue gas stream carrying heat energy. Under an initial initial ignition is understood in particular a short-term supply of energy, in particular heat energy, which is necessary to overcome a necessary for the oxidation reaction, typical for a mixture of the fuel and the oxidizing agent ignition temperature.

In this case, a heat consumer is understood in particular to mean a device, a system or a system for carrying out a utilization process, wherein for carrying out the utilization process Heat energy or process heat is necessary. Such useful processes can be, for example, drying processes, chemical, in particular endothermic, chemical processes, evaporation processes and / or melting processes.

The invention makes use of the fact that the exhaust gas stream contains considerable amounts of heat energy, also referred to as waste heat, which can be used in plants for combined heat and power as a process heat source. Optionally, the invention also makes use of the fact that a part of air sucked in by the internal combustion engine and unburned by the internal combustion engine and / or the internal combustion engine cooling air (so-called "scavenging air") may contain waste heat, which may also be reused.

According to the invention it is therefore proposed that the heat pump unit has at least one heat pump with an electric drive and the internal combustion engine for the interaction of internal combustion engine and heat pump unit drives a generator for providing electrical energy, which is at least partially, preferably almost completely fed to the electric drive of the heat pump , Due to the preferred supply of the electric drive of the heat pump on the generator driven by the internal combustion engine, there is the possibility of ideal match generator and electric drive, in particular the generator and the electric drive designed so that the system or the system over a range of Operating states across an increased compared to the prior art efficiency.

An idea of the invention is, in particular, that the internal combustion engine can be arranged in a substantially closed housing, which preferably has an inlet opening for the entry of some of the process air and to another part as purge air intake air and an outlet opening for the exit of the Having as a scavenging air acting part of the intake air. In this case, the heat of the purging air emerging from the housing for the effect coupling of internal combustion engine and heat pump unit can be at least partially fed to the heat pump unit at a heat input. It may additionally be advantageous if the heat pump unit cools the exiting the housing air flow to a temperature below a dew point.

In this case, a dew point of a gaseous fluid, in particular of a gas or gas mixture, is understood as meaning a limit temperature, below which at least one gas fraction or gas species, in particular steam taken up in the gaseous fluid, eg. As water vapor to a liquid, d. H. condensed condensate. As a result, additional latent heat energy can be withdrawn from the fluid and provided or transmitted for use via the heat pump unit.

In particular, it is advantageous in this case to provide a device for separating and / or collecting condensate from the fluid, in particular the purging air.

In order to use the heat in the flue gas stream of an internal combustion engine, a system according to the invention may include a flow channel for guiding the flue gas stream of the internal combustion engine to a heat consumer to transfer heat from the flue gas stream, and a return duct to a with a heat input of the Heat pump unit thermally coupled heat exchanger. It may also be advantageous here if the heat pump unit cools the flue gas stream which can be fed to the heat exchanger to a temperature below a dew point in the sense of the preceding description, as a result of which large heat transfer rates can be achieved from the flue gas stream to the heat pump unit. For the controlled removal of condensate, a device for the separation and / or collection of condensate from the flue gas stream can also be advantageous here to extract moisture from the system, the z. B. is caused by the resulting in the combustion of hydrocarbon fuels water vapor.

The internal combustion engine can have a compressor for compressing at least one part of the intake air which passes through the inlet opening as a process air to a combustion chamber of the internal combustion engine in a burner air stream as an oxidized compressed process air.

In order to increase the performance of the internal combustion engine in the system, if this at high ambient temperatures, eg. B. is used in the tropics, it may be beneficial if the heat of the compressor feedable process air for the effect coupling of internal combustion engine and Heat pump unit can be supplied at least partially before entering the compressor of the heat pump unit to a heat input.

In addition, the heat of the process air can here be cooled to a temperature below a dew point in the sense of the preceding description, whereby it is possible to extract heat from the process air, which is supplied to the compressor, with a high heat transfer rate. For the controlled separation and / or collection of condensate from the process air cooled by the heat pump unit, a device for separating and / or collecting condensate can likewise be advantageous here.

According to the invention it is also proposed that a burner air flow of the internal combustion engine for the effect coupling of internal combustion engine and heat pump unit is at least partially supplied via a channel for compressed process air of the heat pump unit as a heat source. Here, too, can be achieved with a heat pump unit, which cools the burner air flow to a temperature below a dew point in the sense of the previous description, large heat transfer rates. For the controlled collection or separation of condensate, a device for separating and / or collecting condensate from the burner air flow can also be advantageous here.

The system can also in an advantageous development of the invention, at least one heat storage for the buffering of heat from the exhaust stream and / or at least one heat storage for the buffering of heat from the inlet through the inlet opening into the housing intake air and / or at least one heat storage for the Caching the heat energy provided by the heat pump unit. This heat storage can, for. B. be designed as a hot water tank or hot water tank or steam storage or phase change memory or latent heat storage.

An idea of the invention is also to provide in a system for converting energy for combined heat and power optionally additionally also a coupling effect of the heat pump unit with a cold consumer. In addition, a system according to the invention may also contain at least one cold storage for temporarily storing refrigeration provided with the heat pump unit. Cold is understood to mean a reservoir with a medium which has a considerable absorption capacity for thermal energy at standard or ambient temperature or lower temperatures. Such a cold storage can, for. B. be designed as a cold water storage or ice storage or as a phase change memory.

It is advantageous if the internal combustion engine is designed as a gas turbine system, in particular as a micro gas turbine system. In this case, a preferred gas turbine system comprises at least one burner, preferably a controllable or controllable multi-stage burner, in particular with a pilot stage and at least one controllable or controllable main stage, a turbine drivable via an exhaust gas flow of the burner and a compressor drivable via the turbine. Furthermore, a generator for providing electrical energy is preferably provided, which can also be driven by the turbine. Optionally, the gas turbine system further comprise a heat exchanger acting as a recuperator, through which part of the heat energy of the exhaust gas stream can be transmitted to an oxidant stream, in particular burner air stream, supplied to the burner.

An idea of the invention is also that the heat pump unit has a thermally coupled with a heat transfer device heat connection for providing heat energy at the second temperature level T ₂ , which is for providing heat energy at a higher temperature compared to the second temperature level T ₂ T _{3 is} thermally coupled to a further heat connection with a heat from the exhaust gas stream of the internal combustion engine acted upon heat transfer device.

With this measure, it is possible to provide heat energy at a temperature level higher than the temperature level at the heat connection of the heat pump unit.

The invention also extends to a method for converting chemical energy contained in a fuel into heat energy, wherein the heat energy is supplied to a first heat consumer at a first temperature level and wherein a second heat consumer different from the first heat consumer, the heat energy on a preferably obtains different further temperature level from the first temperature level.

In the following the invention will be explained in more detail with reference to the embodiments schematically illustrated in the drawing.

Show it:

1 a first plant for providing heat energy with a heat consumer;

2 a second plant for providing heat energy for heat consumers;

3 a third plant for providing heat energy for heat consumers;

4 a fourth system for providing heat energy with a heat consumer and cold energy with a cold consumer;

5 and 6 other systems for providing heat energy with a heat consumer; and

7a to 7c Balancing schemes of the net energy flows of preferred applications according to Tab. 1 inventive plants.

The in the 1 shown attachment 10 is designed for combined heat and power. It is used to convert the stored in a fuel, in particular a liquid or gaseous fuel chemical energy into electrical energy and heat that can be supplied to different heat consumers.

The attachment 10 contains one as micro gas turbine system 12 trained internal combustion engine. The micro gas turbine system 12 has a high-speed gas turbine 14 that by means of a wave 16 with a compressor 18 is rotationally coupled. Via an output shaft acting as output unit 20 is due to the micro gas turbine system 12 an electric generator 22 connected for providing an electric power P _el of z. B. P _el ≈ 50, 100, 200 or 400 kW is designed. In the micro gas turbine system 12 there is a burner chamber 24 for the exothermic oxidation of (in particular by means of a compressor 26 compressed gaseous) fuel with an oxidizing agent, in particular compressed oxygen-containing gas mixture, preferably air, from the compressor 18 through an intake air duct 28 with a recuperator 30 the burner chamber 24 is supplied. In the burner chamber 24 This exhaust gas is generated in the form of a hot gas stream. The one in the burner chamber 24 generated hot gas stream is then the gas turbine 14 fed. There, the hot gas stream is released. In this case, the hot gas stream energy is withdrawn and transmitted in the form of kinetic energy to a connected consumer. After flowing through the gas turbine 14 is the first present as a hot gas flow exhaust gas in the form of flue gas with reduced pressure to an exhaust unit 50 directed. In a modified embodiment, a liquid fuel for realizing the exothermic oxidation is supplied to the burner chamber in addition to the oxidizing agent.

The gas turbine 14 preferably operates with combustion chamber pressures p _B in a range 2bar ≤ p _B ≤ 6bar, preferably between 3bar ≤ p _B ≤ 5bar, more preferably of about 4bar and temperatures T at an output of the burner chamber 24 , which are in a range between 700 ° C and 1400 ° C, in particular 800 ° C and 1200 ° C, preferably between 850 ° C and 1100 ° C, more preferably between 900 ° C and 1000 ° C and ideally about T ≈ 950 ° C on the amount. The speed of the gas turbine 14 is about 40,000 rpm to 100,000 rpm, in particular 65,000 rpm to 80,000 rpm, more preferably of about 70,000 rpm. In the electric generator 22 becomes the kinetic energy of the high-speed gas turbine 14 converted into electrical energy. The generator 22 is preferably actively cooled. In the plant 10 is there a cooling device for this purpose? 32 with a water and oil cycle passing through the generator 22 is guided.

The micro gas turbine system 12 is preferably in a (at least largely) closed housing 34 arranged, which at least one inlet opening 36 and at least one outlet opening 38 having. The attachment 10 has a preferably designed as Saugzuggebläse blower 40 which serves ambient air through the inlet opening 36 suck in the direction of the arrow 42 to a part of the compressor 18 is supplied as intake air. To another part of the sucked ambient air flows in the form of so-called purge air in the direction of the arrow 44 first in the cooling device 32 and about an entry plenum 46 through the housing 34 , Subsequently, the purging air flows into a discharge plenum 48 and from there to the outlet opening 38 in order to keep from being in the case 34 arranged assemblies waste heat dissipate. In modified embodiments, of course, a plurality of inlet and / or a plurality of outlet openings are optionally providable with different dimensions and / or positioning.

The micro gas turbine system 12 contains an exhaust unit 50 entering an exhaust duct in the form of a so-called flue gas duct 52 opens, which has a flow channel section to which a heat consumer 54 is connected to the heat from the flue gas stream with the flue gas of the gas turbine 14 at a flue gas temperature level T ₁ the heat consumer 54 supply. Depending on the operating mode of the gas turbine 14 in the combustion chamber 24 burned fuel and the combustion conditions set there, the flue gas temperature level can be in a range 200 ° C ≤ T ₁ ≤ 650 ° C.

The heat consumer 54 can z. B. be formed as a furnace, for. B. as a large oven in a bakery or as a dryer system, for. B. as a dryer system with a dryer tunnel for motor vehicle bodies in a paint shop.

In the plant 10 is there a heat pump unit 56 with a heat pump 58 , The heat pump unit 56 serves to provide heat energy at a heat connection 82 at a temperature level T ₂ with ~ 80 ° C ≤ T ₂ ≤ ~ 160 ° C for one or more other heat consumers (not shown), the z. B. as a heating system or as a device for the treatment of hot, hot water and / or steam can be formed.

The heat pump 58 has a heat input 62 on. It contains a circuit in which a working medium is guided. The heat pump has an electric drive 64 for driving a conveyor, which moves the working fluid through the circuit to thereby heat the heat input 62 is supplied at a temperature level T ₃ <T ₂ , to the heat output 60 to pump.

The heat pump unit 56 in the plant 10 is with the micro gas turbine system 12 effectively coupled. The electric drive 64 the heat pump 58 This is done with electrical energy from the electric generator 22 driven. In a particularly preferred embodiment of the invention are the electric generator 22 and electric drive 64 designed, in particular coordinated with each other, that an electromechanical efficiency of the overall system is optimized, in particular over a speed range of 10%, in particular 15%, preferably 20% to the design point of the generator 22 less than 10%, in particular less than 5%, preferably less than 2.5%, deviates from the optimum.

The heat input 62 the heat pump 58 receives residual heat from the due to thermal contact with the heat consumer 54 to the temperature T ₁ `cooled flue gas stream in the flue gas duct 52 through a return passage section 66 , one with one with the heat input 62 the heat pump 58 thermally coupled heat exchanger 68 is guided.

Preferably, the heat pump allows 58 doing, in the return passage section 66 flowing flue gas stream to cool to below at least one dew point of a partial gas of the flue gas stream temperature. For the separation and collection of condensate formed thereby from the flue gas stream is the heat exchanger 68 in particular a device 70 assigned for the separation and collection of condensate.

The heat input 62 the heat pump 58 alternatively or additionally receives heat from the through the outlet opening 38 flowing air passing through a purge air duct 72 with one with the heat input 62 thermally coupled heat exchanger 74 is guided. With the heat pump 58 can the through the scavenging air duct 72 flowing air preferably at a temperature below a dew point of a partial gas in the scavenge air duct 72 be cooled flowing air. This partial gas is thereby at least partially converted into a condensate. For the separation and collection of condensate from the flue gas stream is the heat exchanger 74 An institution 76 assigned for the separation and collection of condensate.

For the caching of the flue gas stream withdrawn residual heat is in the system 10 in the plant 10 optional, ie not mandatory, one with the heat input 62 the heat pump 58 thermally coupled heat storage 78 intended. To those with the heat pump 58 at the heat output 60 To buffer provided heat, in particular, there is a heat storage 80 be provided.

With the heat pump unit 56 can in the plant 10 Heat at the temperature level T ₂ at the heat output 82 to be provided.

The in the 2 shown attachment 110 for the cogeneration has a micro gas turbine system 112 with a channel for compressed process air 128 in which a heat exchanger 131 is arranged, by means of which in the compressor 118 compressed process air heat can be withdrawn. As far as the modules in the system 110 with the modules of the plant 10 from the 1 are identical or at least functionally identical, these have in the 2 with respect to the 1 around the number 100 increased numbers as reference numerals.

In the plant 110 is there a heat pump unit 156 with two heat pumps 158 . 159 , The heat pump unit 158 serves to provide heat energy to heat connections 182 . 183 at a temperature level T ₂ , T ₄ with ~ 80 ° C ≤ T _2.4 ≤ ~ 160 ° C for one or more other heat consumers (not shown), the z. B. may be formed as a heating system or as a plant for the treatment of hot, hot water and / or steam.

The heat pumps 158 . 159 each have a heat input 162 . 163 on. They each contain a circuit in which a working medium is performed. The heat pumps 158 . 159 have an electric drive 164 for driving a conveyor which moves the working fluid through the circuit to thereby heat from the temperature range T ₁ , T ₂ of the heat inputs 162 . 163 to heat outputs 160 . 161 to pump. The electric drive 164 is preferably from the generator 122 of the micro gas turbine system 112 fed.

The compressed process air in the micro gas turbine system 112 with the heat exchanger 131 extracted heat is passed through a circulating heat transfer fluid through a heat exchanger 175 on the heat input 163 the heat pump 148 transfer.

The heat pump 159 is designed so that the with the compressor 118 of the micro gas turbine system 112 compressed intake air cools, in particular to a temperature below a dew point of at least one partial gas can be cooled. Preferably, for the separation and collection of condensate from the process air to the heat exchanger 131 An institution 133 assigned for the separation and collection of condensate.

For the intermediate storage of the compressed process air from the intake duct of the micro gas turbine extracted residual heat is available in the system 110 one with the heat input 163 the heat pump 159 thermally coupled heat storage 179 , To those with the heat pump 159 at the heat output 161 To buffer provided heat has the facility 110 there a heat storage 181 ,

With the heat pump unit 156 can in the plant 110 Heat at the temperature levels T ₂ , T ₄ > T ₁ ', T ₃ at heat connections 182 . 183 to be provided.

It should be noted that for a modified embodiment of the in the 2 shown attachment 110 into the micro gas turbine system 112 in addition to the heat exchanger 131 Also, a recuperator can be integrated, its heat output to that for the heat consumer 154 required temperature level for supplying heat is tuned.

The in the 3 shown attachment 210 is designed to convert energy for combined heat and power at high outside temperatures, making it particularly suitable for use in tropical regions. As far as in the 3 shown assemblies of the system 210 with the modules of the plant 10 from the 1 are identical or at least functionally identical, have these in the 3 with respect to the 1 around the number 200 increased numbers as reference numerals.

The in the 3 shown attachment 210 for combined heat and power contains heat exchanger 219 around the compressor 218 in the micro gas turbine system 212 through the inlet opening 236 in the case 234 to cool the supplied air. With this measure, the fuel efficiency of the system 210 be increased when it is operated at high outdoor temperatures, such as in the tropics. The compressor 218 it does not have to be operated at a higher power level than the burner chamber 224 To supply compressed intake air with the same mass flow as at low outdoor temperatures or intake temperatures.

The attachment 210 contains a heat pump unit 256 with two heat pumps 258 . 259 , The heat pump unit 256 serves to provide heat energy to heat connections 282 . 283 at a temperature level T ₂ , T ₄ with ~ 80 ° C ≤ T _2.4 ≤ ~ 160 ° C for one or more other heat consumers (not shown). Such a heat consumer can, for. B. be designed as a device for the treatment of hot, hot water and / or steam.

The heat pumps 258 . 259 each have a heat input 262 . 263 on. They each contain a circuit in which a working medium is performed. The heat pumps 258 . 259 have an electric drive 264 for driving a conveyor that moves the working fluid through the circuit to thereby heat from the heat inputs 262 . 263 to heat outputs 260 . 261 to pump. The electric drive 264 is preferably from the generator 222 of the micro gas turbine system 212 fed.

In the plant 210 is the heat generated by the heat exchanger 219 through the inlet opening 236 in the direction of the arrows 242 flowing air is withdrawn, via a guided in a circulation heat transfer fluid through a heat exchanger 275 at a temperature T ₃ <T ₅ on the heat input 263 the heat pump 248 transferred to.

The heat pump 259 may preferably be designed so that in this case by the heat exchanger 219 flowing air to a temperature of z. B. T ₅ ≈ 5 ° C below the dew point can be cooled. For the separation and collection of condensate is therefore preferably the heat exchanger 219 An institution 233 assigned for the separation and collection of condensate.

For caching from the through the heat exchanger 219 flowing air is available in the system 210 optional, not mandatory, one with the heat input 263 the heat pump 259 thermally coupled heat storage 279 , To those with the heat pump 259 at the heat output 261 To buffer provided heat has the facility 210 there a heat storage 281 ,

With the heat pump unit 256 can in the plant 210 Heat at the temperature levels T ₂ , T ₄ > T ₃ at heat connections 282 . 283 to be provided.

The attachment 310 for converting energy for combined heat and power in the 4 contains a cold connection 385 for a cold consumer. As far as in the 4 shown assemblies of the system 310 with the modules of the plant 210 from the 3 are identical, these have in the 4 with respect to the 3 around the number 100 increased numbers as reference numerals.

The attachment 310 contains a heat pump unit 356 with three heat pumps 358 . 359 and 365 , The heat pump unit 365 is used to provide heat energy to heat connections 382 . 383 . 384 at a temperature level T ₂ , T ₄ , T ₇ with ~ 80 ° C ≤ T _2.4,7 ≤ ~ 160 ° C for several heat consumers (not shown) and a cold connection 385 for a cooling device (not shown). About the cold connection 385 can the cooling device at a temperature level of z. B .: T ₆ ≈ -10 ° C heat to be extracted.

The heat pumps 358 . 359 . 365 each have a heat input 362 . 363 . 367 on. They each contain a circuit in which a working medium is performed. The heat pumps 358 . 359 . 365 have an electric drive 364 for driving a conveyor that moves the working fluid through the circuit to thereby heat from the heat inputs 362 . 363 . 367 to heat outputs 360 . 361 . 369 to pump. The electric drive 364 is preferably from the generator 322 of the micro gas turbine system 312 fed.

For caching from that of the heat pump 365 The heat extracted from the cooling device has the system 310 there a heat storage 387 , For buffering cold is located between the cold connection 385 and the heat pump 365 and a cold storage 389 ,

The in the 5 shown attachment 410 for providing heat energy contains as a heat exchanger 454 trained with heat from the flue gas stream of the internal combustion engine 412 can be acted upon heat consumer and has a heat pump unit 456 , one with the heat exchanger 454 thermally coupled heat connection 482 Has. As far as the modules in the system 410 with the modules of the plant 10 from the 1 are identical, have these in the 5 with respect to the 1 around the number 400 increased numbers as reference numerals. With the plant 410 It is thus possible, at a relation to the second temperature level T ₂ higher temperature level T ₃ at a heat connection 484 Provide heat energy for a heat consumer (not shown).

The in the 6 shown attachment 510 for providing heat energy contains a designed as a mixer heat transfer device 586 in which one in a flue 552 flowing Flue gas flow from the internal combustion engine 512 can be mixed with air, which by a with the heat connection 582 the heat pump unit 556 thermally coupled heat exchanger 586 is guided. As far as the modules in the system 510 with the modules of the plant 10 from the 1 are identical, have these in the 6 with respect to the 1 around the number 400 increased numbers as reference numerals. Also with the plant 510 It is thus possible, at a relation to the second temperature level T ₂ higher temperature level T ₃ at a heat connection 584 Provide heat energy for a heat consumer (not shown).

The heat pumps in the heat pump units of the plants described above preferably have a working medium circuit with the working fluid CO ₂ or NH ₃ , which is expanded and compressed in a thermodynamic cycle. According to the selected temperature level at the heat input and the heat output, the heat pumps with a subcritical, a transcritical or, such. B. in the EP 2 518 423 A2 described, operated a supercritical cycle.

In this context, a subcritical cycle process is understood in particular to be a cyclic process in which the working medium or working fluid is not thermally or thermodynamically stable at any operating or operating point or during any phase of the cycle or in any part of the cycle performing plant or device reaches a characteristic of the working fluid or working fluid critical point or a corresponding critical boundary line in a phase diagram of the working fluid or the working fluid, in particular exceeds.

In this context, a transcritical cycle process is understood to mean in particular a cyclic process in which the working medium or working fluid is subjected to its thermodynamic properties, in particular its thermodynamic state at at least one operating or operating point or during at least one phase of the cycle or in at least one part a plant or apparatus performing the cycle alternately either exceeds or falls below the critical point characteristic of the working fluid or working fluid or the corresponding critical boundary line in a phase diagram of the working fluid or working fluid. In a first phase of the cycle, the working fluid or working fluid was subcritical of its thermodynamic state, i. In particular, its state variables were in the phase diagram below the critical point or the critical boundary line, so one of the state variables in a subsequent phase exceeds the critical point or the critical boundary line, so that the working medium or the working fluid in this phase in a supercritical state located. The working medium or the working fluid experience a phase change, the process represents an additional energy requirement. If the phase change can be realized essentially reversibly, this additional energy requirement can be used as an energy buffer in the cyclic process. For this purpose, in a subsequent phase of the cyclic process, the working medium or the working fluid is again relaxed, cooled and / or transferred in terms of its state variables below the critical point or the critical boundary line, so that in the then running in the reverse direction phase change of the additional energy substantially is released again.

By contrast, a supercritical or hypercritical cycle process is understood in particular to mean a cyclic process in the course of which the working medium or working fluid does not undergo any thermodynamic properties, in particular its thermodynamic state, at any operating or operating point, or during virtually any, preferably every phase of the cycle in almost any part of a system or apparatus performing the cycle above the critical point characteristic of the working fluid or working fluid or the corresponding critical boundary line in phase diagram.

Further modifications and developments of a system according to the invention can result inter alia by combining various features of the embodiments described above. This results, for example, in advantageous systems according to the invention 10 through a changed number of heat pumps 58 . 158 . 159 . 258 . 259 . 358 . 359 . 365 . 458 . 558 in the system, the combination of heat pumps with low-temperature and those with high-temperature heat sources on the input side and / or by parallel or series connection of the heat flow from the micro gas turbine with a pumped heat flow at least one heat pump of the system 10 , Also, the provision of one or more heat and / or cold storage as a buffer in the heat-carrying streams, as exemplified in the examples of 1 . 2 . 3 . 5 or 6 are shown, can lead to advantageous developments of a system according to the invention. By means of such heat and / or cold storage, inter alia, it is advantageously possible to compensate, attenuate or compensate for fluctuations in the heat flows.

In the following 7a to 7c schematically represent the net energy balances or net energy flows of some selected application examples according to Table 1 of a plant according to the invention 10 shown as particularly preferred embodiments of one of the variants of the invention described above.

7a shows the net energy balance for a hot water with at least one, preferably two consumers with a large temperature spread of 90 ° C / 20 ° C between flow and return according to Example 1.1 of Table 1 as the first use of a system according to the invention 10 according to one of the preceding embodiments. The heat engine 12 sets it in the fuel stream 900 stored chemical energy through an exothermic oxidation with the oxidant stream 902 with an efficiency of η ≈ 0.35 in electrical energy, which is about the electric current 904 the electric drive of the heat pump unit 56 is supplied.

In the present case, the ratio η of a heat engine of a heat engine is understood to mean the ratio of the electrical energy generated or provided by the heat engine to the chemical energy of the fuel used for this purpose.

The simultaneously released during power generation, entrained in the exhaust stream thermal energy can be used as the first useful heat flow 906 be supplied with a flow temperature T1 in _{front of} a first consumer, not shown. The consumer cools the useful heat flow 906 to the reflux temperature T1 _back from, with which a first Nutzwärmekreislauf in the system can be closed. A waste heat z. B. from the scavenging air of the heat engine 12 , a warming fresh air stream 902 / 903 the heat engine 12 , from the return of the useful heat flow 906 and / or another heat source having a source temperature TQ _to the heat pump unit 56 supplied on the source side. A favorable source temperature is about 35 °. In this preferred embodiment, the heat pump unit 56 operated transcritical, so that the high temperature difference of at least 50K in the heat pump cycle 908 - Preference is also here a temperature spread in the second, from the heat pump unit 56 fed Nutzwärmekreis 908 set from T2 _before ~ 90 ° C in the flow and T2 _back ~ 20 ° in the return - a high coefficient of performance of β ≈ 4 of the heat pump unit 56 is reached. Under a transcritical operation of a heat pump unit 56 is an operating mode or operating method of the heat pump unit 56 understood, in which the working fluid or the working fluid undergoes a trans-critical cycle. In this context, heat pump units 56 or heat pumps, which have a transcritical mode of operation or are subjected to this or run, referred to as trans-critical heat pumps.

Heat pump units for carrying out a transcritical cycle process are characterized in particular by a turbocompressor / turbocompressor, an evaporator and a gas cooler. The turbocompressor / turbocompressor belongs to the thermal turbomachinery. He works in the reversal of the principle of the turbine, similar in components and structure of the centrifugal pump and also promotes the respective medium by transmitting kinetic energy in the form of a swirl pulse. In contrast to the pump, the gas is compressed in the compressor, that is, at the same mass flow, the flow rate at the outlet is lower. The required volume change work does not have to be applied by a pump, which is why, with the same pressure build-up, the pumping work is considerably lower than the compressor or compressor work. For this reason, steam power plants operate more efficiently than comparable power plants operated with air / gas. Preferably, the turbocompressors used in a transcritical heat pump operate oil-free, i. The moving parts, such as the compressor wheel, are stored in the compressor housing without oil. In the case of transcritical heat pumps, the combination as evaporator and gas cooler replace the condensers or condenser units customary in conventional, subcritical heat pumps for the recondensation and initiation of a recirculation of the working medium or working fluid.

Transcritical heat pump units preferred according to the invention 56 comprise as working medium CO ₂ , which is biased in the turbocompressor to process pressures of at least 100 bar and up to 120 bar, preferably up to about 130 bar.

If the pressure level in the turbocompressor is further increased, for example up to 150 bar, in particular up to 160 bar, and the gas cooler is supplemented by a gas heater in the circuit, the CO ₂ -based heat pump unit just described 56 also be operated purely supercritical or hypercritical. For a supercritical heat pump unit 56 The turbocompressor is preferably additionally supplemented by a device for work-performing expansion of the working medium.

In this case, the coefficient of performance β of a heat pump unit is understood as meaning the ratio of the heat and / or cooling capacity of the heat pump unit to the electrical or mechanical power which must be supplied to the heat pump unit for operation therefor.

Is in the heat pump unit 56 In particular, a CO ₂ turbo compressor used, the flow temperature T2 can be increased _before even over 100 ° C. For a further increase in the fuel efficiency can optionally be a calorific value in the heat engine 12 be used. In this way, a total fuel efficiency of up to 205% can be achieved. In principle, it is conceivable in this application example that the heat flows 906 and 908 be supplied in parallel to two different consumers or via a merge or a mixer to a single consumer.

Alternative applications with an energy balance scheme 7a are summarized as Examples 1.2 to 1.4 in Table 1. Notwithstanding the example described above, in this case, the low-temperature side of the heat pump unit 56 for providing process refrigeration, e.g. B. by lowering a fluid temperature of TQ _to ~ -4 ° C to TQ _back ~ -10 ° C (for example, providing cold brine) used. The applications 1.2 to 1.4 differ in the temperature difference between flow and return of useful heat flows 906 and 908 , Reference is here made to the details in Table 1. Is in the heat pump unit 56 In particular, a CO ₂ turbo compressor used, the flow temperature T2 can be increased _before even over 100 ° C. For a further increase in the fuel efficiency can optionally be a calorific value in the heat engine 12 be used. In this way, a total fuel efficiency between 160% and over 200%, preferably up to 205% can be achieved.

Another preferred application according to 1.5 of Table 1 results for a hot water preparation similar to the application described above 1.1, however, for heat consumers with a low temperature spread with a temperature difference between supply and return of a maximum of 50K and without the use of the condensing effect. The lower temperature spread leads to a significantly lower coefficient of performance of the heat pump unit 56 of β ≈ 3, so that at identical source current comparatively more electrical energy from the heat engine 12 to operate the heat pump unit is required. As a consequence, this leads to an overall reduced fuel efficiency of the system according to the invention 10 However, the fuel efficiency here can still be up to 160%.

A further preferred application according to 1.6 of Table 1 results for two different heat consumers, wherein the first heat consumer on the Nutzwärmestrom 906 to 7a is supplied with heat energy and thereby has a very low temperature difference between flow and return of about 20K. The second heat consumer in turn has a large temperature difference between supply and return of min. 50K, preferably at least 70K and can therefore via the transcritical heat pump unit 56 with high coefficient of performance of β ≈ 4 over the useful heat flow 908 be supplied. Particularly preferred flow and return temperatures are summarized in line 1.6 of Table 1. Is in the heat pump unit 56 In particular, a CO ₂ turbo compressor used, the flow temperature T2 can be increased _before even over 100 ° C. For a further increase in the fuel efficiency or if the capacity of the waste heat sources is not sufficient, optionally a calorific value utilization in the heat engine 12 be used. In this way, a total fuel efficiency of a plant of up to 205% can be achieved.

Another application with an energy balance according to 7a is summarized in 1.7 of Table 1. Here, one or two consumers hot water with a low temperature spread of about 20K between supply and return, for example, 60 ° C -> 40 ° C provided, the heat source of the heat pump has an elevated temperature TQ _to min of 40 ° C. , The hypercritical heat pump unit 56 must have a CO ₂ turbo compressor with a minimum power of 500kW thermally, but so achieves a high coefficient of performance of β ≈ 4. For a further increase in the fuel efficiency or if the capacity of the waste heat sources is not sufficient, optionally a calorific value in the heat engine 12 be used. In this way, a total fuel efficiency of a plant of up to 205% can be achieved.

With a hypercritical high-temperature heat pump unit 56 with a CO ₂ turbo compressor with a thermal capacity of min. 500kW can also heat sources with min. 60 ° C still open up and inventive plants 10 for use with hot water and / or Utilize steam supply of a consumer, as in Examples 1.8 and 1.9 of Table 1 in connection with the energy balance scheme after 7a is summarized. Example 1.8 supplies both the useful heat flow 906 as well as the useful heat flow 908 one or more heat consumers with hot water or steam at a temperature spread of about 40K between supply and return. Variant 1.9 supplies the useful heat flow 906 with a temperature spread of min. 40K, z. B. 130 ° C -> 90 ° C, a first consumer with hot water and / or steam, while the heat pump unit 56 a second consumer with the useful heat flow 906 at a lower temperature level, e.g. B. 120 ° C -> 80 ° C supplied. Due to the high temperature source _TQ min. 60 ° C, the heat pump unit achieves a coefficient of performance of β ≈ 3. However, a fuel efficiency of a system can be up to 160%.

An alternative application according to 1.10 of Table 1 is based on a net energy balance 7b or 7c , In this application, a first consumer hot water and / or steam with a temperature difference between flow and return of min. 40K, z. B. 130 ° C -> 90 ^ C on the heat engine 12 in the useful heat flow 906 made available. While either a second consumer hot water with a large temperature difference of min. 50K, preferably 70K between supply and return, z. B. 90 ° C -> 20 ° C is provided and / or at least a portion of the heat flow 908 via a series connection of the heat engine for preheating the heat flow 906 is supplied. Again, the high temperature difference on the HT side of the transcritical heat pump unit 56 achieved a high coefficient of performance of β ≈ 4. Is in the heat pump unit 56 In particular, a CO ₂ turbo compressor used, the flow temperature T2 can be increased _before even over 100 ° C. For a further increase in the fuel efficiency or if the capacity of the waste heat sources is not sufficient, optionally a calorific value utilization in the heat engine 12 be used. In this way, a total fuel efficiency of a plant up to 205% can be achieved.

For heat sources of at least 50 ° C can be realized with a hypercritical operated, a CO ₂ turbo compressor with a minimum power of 500 kW thermal heat pump unit application according to 1.11 of Table 1. Here, a first consumer steam and / or hot water with a temperature difference of min. 40K between supply and return, z. B. 130 ° C -> 90 ° C above the useful heat flow 906 the heat engine 12 made available. The useful heat flow 908 can in turn in parallel to provide hot water with a temperature difference of about 30K between flow and return, z. B. 90 ° C -> 60 ° C. In a series connection after 7b or 7c is also a preheating of the heat flow 906 conceivable. With such systems, a fuel efficiency of up to 195% can be achieved.

Two further application examples 1.12 and 1.13 are summarized in Table 1, the summary of which is referenced at this point.

A particularly preferred application is not shown in Table 1 but is based on an energy balance scheme 7a , while doing a pre-cooling of the oxidant stream 902 / 903 is provided. At the same time, the low-temperature side of the heat pump unit is used 56 a cooling of a cooling air flow of z. B. TQ _to ~ 12 ° C on _back TQ ~ 6 ° C. The useful heat flows 906 and 908 be further provided for the provision of hot water with a temperature difference of min. 50K, preferably min. 70K between flow and return, z. 90 ° C -> 20 ° C. In this application, the heat pump unit reaches 56 a particularly coefficient of performance of β ≈ 5.9, the overall system thereby achieving a fuel efficiency of up to 270%. Such an application is particularly suitable for the simultaneous supply of hotel complexes, public buildings or other large building complexes with air conditioned indoor air and hot water. Is in the heat pump unit 56 In particular, a CO ₂ turbo compressor used, the flow temperature T2 can be increased _before even over 100 ° C. For a further increase in the fuel efficiency can optionally be a calorific value in the heat engine 12 be used. In addition, the intake air of the heat engine 12 via the heat pump unit 56 Chilled, the performance of the plant can 10 be increased again.

In a refrigeration application or cooling application, a subcritically operated CO2 heat pump of a heat pump unit can 56 be provided, which can be switched from subcritical to a transcritical operation when a maximum, in particular maximum permissible, preferably adjustable limit of a recooling temperature of the operating mode of the CO2 heat pump is exceeded or is exceeded. Such a bimodal mode of operation or bimodal heat pump can be provided in particular for summer operation, in particular in applications in climatically demanding environments which are highly variable or varying with respect to an ambient temperature. Under a strongly variable or In this context, varying ambient temperature is understood in particular to be an ambient temperature with a peak-to-peak difference between maximum and minimum of at least 30K, in particular at least 40K, preferably at least 50K.

In summary, the following preferred features of the invention are to be noted in particular: A plant 10 for converting energy for cogeneration includes an internal combustion engine 12 , which is an output unit, in particular an output shaft 20 for providing mechanical energy. In addition, the plant has 10 an exhaust unit 50 for providing heat energy via an exhaust stream at a first temperature level T ₁ . The heat pump unit 56 is for the provision of heat energy at one of the first temperature level T ₁ preferably different further temperature level T ₂ with the internal combustion engine 12 effectively coupled. Furthermore, it is preferable that the further temperature level T _{2 is selected to be} lower than the first temperature level T ₁ .

LIST OF REFERENCE NUMBERS

10

 investment

12

 Micro gas turbine system (internal combustion engine)

14

 gas turbine

16

 wave

18

 compressor

20

 output shaft

22

 generator

24

 burner chamber

26

 compressor

28

 Channel (intake air duct)

30

 recuperator

32

 cooling device

34

 casing

36

 Inlet opening (inlet opening)

38

 outlet

40

 induced draft fan

42

 arrow

44

 arrow

46

 admission plenary

48

 distribution plenum

50

 gas unit

52

 Exhaust duct in the form of a flue gas duct

54

 heat consumer

56

 heat pump unit

58

 heat pump

60

 Heat output

62

 Heat input

64

 drive

66

 Return channel section (return channel)

68

 heat exchangers

70

 Facility

71

 Facility

72

 scavenging air

74

 heat exchangers

76

 Facility

78

 heat storage

80

 heat storage

82

 Heat connection (heat output)

110

 investment

112

 Micro gas turbine system (internal combustion engine)

118

 distributor

121

 combustion engine

122

 generator

124

 combustion chamber

128

 channel

131

 heat exchangers

133

 Facility

134

 casing

136

 Inlet opening (inlet opening)

148

 heat pump

156

 heat pump unit

158

 heat pump

159

 heat pump

160

 Heat output

161

 Heat output

162

 Heat input

163

 Heat input

164

 drive

175

 heat exchangers

178

 heat storage

179

 heat storage

180

 heat storage

181

 heat storage

182

 Heat connection

183

 Heat connection

210

 investment

212

 Micro gas turbine system (internal combustion engine)

218

 compressor

219

 heat exchangers

222

 generator

224

 burner chamber

228

 channel

233

 Facility

234

 casing

236

 Inlet opening (inlet opening)

242

 arrow

256

 heat pump unit

258

 heat pump

259

 heat pump

260

 Heat output

261

 Heat output

262

 Heat input

263

 Heat input

264

 drive

275

 heat exchangers

278

 heat storage

279

 heat storage

280

 heat storage

281

 heat storage

282

 Heat connection

283

 Heat connection

310

 investment

312

 Microturbine system

322

 generator

356

 heat pump unit

358

 heat pump

359

 heat pump

360

 Heat output

361

 Heat output

362

 Heat input

363

 Heat input

364

 electric drive

365

 heat pump

367

 Heat input

369

 Heat output

382

 Heat connection

383

 Heat connection

385

 Cold connection

387

 heat storage

389

 cold storage

410

 investment

412

 Internal combustion engine

454

 Heat exchanger (heat transfer unit)

456

 heat pump unit

482

 Heat connection

484

 Heat connection

510

 investment

512

 Internal combustion engine

552

 Flue

554

 heat exchangers

556

 heat pump unit

582

 Heat connection

584

 Heat connection

586

 Heat exchanger (heat transfer device)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2518423 A2 [0071]

Claims (24)

Investment ( 10 ) for providing heat energy for heat consumers with an internal combustion engine ( 12 ), which is an output unit, in particular a ( 20 ) Has output shaft for the provision of mechanical energy and the one exhaust unit ( 50 ) for the provision of heat energy at a first temperature level (T ₁ ) with an exhaust gas stream, characterized by a heat pump unit ( 56 ) for the provision of heat energy at a second temperature level (T ₂ ) which is preferably different from the first temperature level (T ₁ ) and which is connected to the internal combustion engine ( 12 ) is effect coupled. Installation according to claim 1, characterized in that the heat pump unit ( 56 ) comprises at least one transcritical heat pump. Plant according to claim 2, characterized in that a working medium of the transcritical heat pump contains CO2, in particular essentially consists thereof, and comprises a turbo-compressor for setting or increasing a process pressure of the working medium. Installation according to one of the preceding claims, characterized in that the heat pump unit ( 56 ) at least one heat pump ( 58 ) with an electric drive ( 64 ) and the internal combustion engine ( 12 ) for the effect coupling of internal combustion engine ( 12 ) and heat pump unit ( 56 ) a generator ( 22 ) for providing electrical energy which at least partially, preferably almost completely, drives the electric drive ( 64 ) of the heat pump ( 58 ). Installation according to one of the preceding claims, characterized in that the internal combustion engine ( 12 ) in a substantially closed housing ( 34 ) arranged with an inlet opening ( 36 ) for the entry of intake air acting as part of a process air and to another part as purge air and an outlet opening ( 38 ) is provided for the escape of the purging air acting as part of the intake air, wherein the heat of the out of the housing ( 34 ) emerging as purge air portion of the intake air for the effect coupling of internal combustion engine ( 12 ) and heat pump unit ( 56 ) at least partially the heat pump unit ( 56 ) at a heat input ( 62 ) can be fed. Installation according to claim 5, characterized in that the heat pump unit ( 56 ) from the housing ( 34 ) emerging as purge air portion of the intake air cools to a temperature below a dew point. Plant according to claim 6, characterized by a device ( 70 ) for the separation and / or collection of condensate from the purging air leaked from the housing. Installation according to one of claims 1 to 7, characterized by a flow channel for guiding the exhaust gas flow of the internal combustion engine ( 12 ) - in particular in the form of a flue gas stream - to a heat consumer ( 54 ) to transfer heat therefrom from the exhaust gas stream, and a return channel ( 66 ) for guiding the exhaust gas flow subjected to residual heat to one with a heat input ( 62 ) of the heat pump unit ( 56 ) thermally coupled heat exchanger ( 68 ). Plant according to claim 8, characterized in that the heat pump unit ( 56 ) the heat exchanger ( 68 ) cools the supplyable exhaust gas stream to a temperature below the dew point. Plant according to claim 9, characterized by a device ( 76 ) for separating and / or collecting condensate from the exhaust stream. Installation according to one of claims 1 to 10, characterized in that the internal combustion engine ( 112 . 212 ) a compressor ( 118 . 218 ) for the compression of the process air acting as part of the inlet opening ( 136 . 236 ) passing through intake air to a combustion chamber ( 124 . 224 ) of the internal combustion engine ( 121 . 212 ) as an oxidant in a burner air stream through a compressed process air channel ( 128 . 228 ) has deliverable compressed process air. Plant according to claim 11, characterized in that the heat of the compressor ( 218 ) feedable as process air portion of the intake air for the effect coupling of Internal combustion engine ( 212 ) and heat pump unit ( 256 ) at least partially before entering the compressor ( 218 ) of the heat pump unit ( 212 ) at a heat input ( 263 ) can be fed. Plant according to claim 12, characterized in that the heat pump unit ( 256 ) the compressor ( 218 ) can be supplied to a part of the intake air acting as process air to a temperature below a dew point. Plant according to claim 13, characterized by a device ( 233 ) for separating and / or collecting condensate from the heat pump unit ( 256 ) cooled as process air acting part of the intake air. Plant according to claim 14, characterized in that the heat pump unit ( 156 ) cools the burner air flow to a temperature below the dew point. Installation according to one of claims 1 to 15, characterized by at least one heat storage ( 78 . 178 . 179 . 278 . 279 ) for the temporary storage of heat from the flue gas stream and / or at least one heat store ( 78 . 178 . 278 ) for the temporary storage of heat from the part acting as purging air through the inlet opening ( 36 . 136 . 236 ) in the housing ( 34 . 134 . 234 ) inlet air and / or at least one heat storage ( 80 . 180 . 181 . 280 . 281 ) for the temporary storage of the heat pump unit ( 56 . 156 . 256 ) provided heat energy. Plant according to claim 16, characterized in that the at least one heat storage ( 78 . 178 . 179 . 278 . 279 ) is designed as a hot water tank or as a hot water tank or as a steam storage or as a phase change memory. Installation according to one of claims 1 to 17, characterized in that the heat pump unit ( 356 ) is effectively coupled with a refrigeration appliance. Plant according to claim 18, characterized by at least one cold storage ( 389 ) for caching cold provided with the heat pump unit. Plant according to claim 19, characterized in that the cold storage ( 389 ) is designed as a cold water storage or as an ice storage or as a phase change memory. Installation according to one of claims 1 to 20, characterized in that the internal combustion engine as a gas turbine system, in particular as a micro gas turbine system ( 12 ) is trained. Installation according to one of claims 1 to 21, characterized in that the heat pump unit ( 56 ) a thermally coupled to a heat transfer device heat connection ( 482 . 582 ) for the provision of heat energy at the second temperature level (T ₂ ), which for the provision of heat energy at a higher temperature level (T ₃ ) than the second temperature level (T ₂ ) at a further heat connection ( 484 . 584 ) with a heat from the exhaust stream of the internal combustion engine ( 412 ) acted upon heat transfer device ( 454 . 586 ) is thermally coupled. A method of converting chemical energy contained in a fuel with a system as claimed in any one of claims 1 to 22 ( 10 ) in heat energy, in which a first heat consumer ( 54 ) Heat energy at a first temperature level (T ₁ ) is supplied and in which one of the first heat consumer different second heat consumer thermal energy or with cold energy at a different temperature from the first temperature level (T ₁ ) further temperature level (T ₂ ) receives. Use of a system ( 10 ) comprising at least one heat engine driven by an exothermic oxidation of a fuel ( 12 ) heat pump unit ( 56 ) for providing process refrigeration, process heat, steam, hot and / or hot water, in particular according to one of claims 1 to 22, characterized by a fuel efficiency of at least 150%, in particular at least 160%, preferably min. 190%.

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