EP2602444A1 - Method and apparatus for generating electric power from waste heat - Google Patents

Abstract

The method involves compressing used refrigerants by a factor of about 15 to 25, and conveying and bottom-heating the compressed refrigerants by a recuperator (17). The highly compressed bottom-heated refrigerants are conveyed by a heat exchanger i.e. preheating unit (12), and preheated. The highly compressed and preheated refrigerants are conveyed through another heat exchanger i.e. vaporization unit (11), and heated refrigerant vapor is vaporized. The heated refrigerant vapor is released in a turbine (18) i.e. turbo expansion machine. Released energy is utilized to drive a generator (19). The refrigerants are azeotrophe mixture based on perfluoropolyether and pentafluorobutane. An independent claim is also included for a device for generating electric current from waste heat.

Description

The present invention relates to a method and apparatus for generating waste electrical energy according to the features of the preambles of claims 1 and 7.

State of the art

Methods for using waste heat from combined heat and power plants, biogas plants, etc. are known. Frequently, the so-called ORC (Organic Rankine Cycle) method is used. In this case, electricity is obtained from heat, in particular by the operation of steam turbines with a working fluid other than water vapor. The method is mainly used when the available temperature gradient between the heat source and sink is too low for the operation of a turbine driven by steam. In particular, the ORC method is therefore used when the waste heat is insufficient to heat water to its vaporization temperature. The expansion machines (turbine, screw expander) are typically operated with silicone oil, refrigerant or a combustible gas.

DE 102007062085 A1 describes a method and apparatus for generating electricity from heat, wherein in the return line of the evaporator medium, an additional heat exchanger is provided, is fed to the extraneous heat to preheat the returning medium to the evaporator.

DE 102009049476 A1 describes a method for power generation from the waste heat of CHP plants by means of an ORC process, with a suitable for the compressed air operation turbine is used as an expansion device, which is operated with the working fluid Frigen R245fa and oil-free. The evaporation and condensation of the refrigerant used is below 90 ° C. This system is therefore not suitable for use when the exhaust gases have a temperature of> 100 ° C.

US2012-0131918 A1 describes heat engines with cyclic cascades to extract energy from waste heat. In this case, an exhaust gas heat exchanger is connected to an exhaust gas generator, so that to heat with the waste heat of the exhaust gas, a first working fluid flow. Furthermore, a first expansion device is provided which receives the first stream from the exhaust gas heat exchanger and thus rotates a shaft. A first recuperator receives the first working fluid flow from the first expansion device and transfers the heat to a second working fluid flow. The second working fluid stream coming from the recuperator is taken up by a second expansion device, which transfers the heat of the second working fluid flow to a combined first and second working fluid flow.

US 2008/0115922 A1 shows an exhaust heat recovery heat exchanger comprising a housing having a working fluid inlet, a working fluid outlet, an exhaust inlet and an exhaust outlet, an exhaust gas flow path extending through the housing between the exhaust gas inlet and the exhaust gas outlet, and a working fluid flow path extending through the housing between the working fluid inlet and the exhaust gas flow path Working fluid outlet extends and comprising a first part and a second part. A flow of the working fluid along the first part of the working fluid flowpath may be substantially opposite to a flow of the exhaust gas along the exhaust gas flowpath and the flow of the working fluid along the second part of the working fluid flowpath.

US 4334409 pursues the goal of leading the use of internal combustion engines and in particular of large turbocharged diesel engines very economically. This should be done in particular using the heat generated by the engines. In the described method, the working medium is additionally preheated with the aid of the heat energy of the air emerging from the charging fan of the internal combustion engine. The device according to the invention is designed so that the preheating circuit of the working medium comprises a heat exchanger, which is fed by the expiring from the supercharger of the engine air and is connected in series with a flowed through by the cooling medium of the engine heat exchanger.

WO2012 / 064477 A2 describes a chemical compound for use as a working medium in waste heat recovery and energy recovery systems.

The object of the invention is to provide a device and a method for using waste heat with temperatures> 200 ° C.

The above object is achieved by a method and an apparatus comprising the features in claims 1 and 7. Further advantageous embodiments are described by the subclaims.

description

The invention relates to a method and apparatus for generating electric power from waste heat. This serves in particular the use of waste heat, which, for example, in the operation of combined heat and power plants, biogas plants or the like. arises. In this case, it is particularly intended to make waste heat with a temperature of over 200 ° C directly usable.

The device serves to generate electric current, in particular by means of an ORC process. The apparatus includes a refrigerant storage, a refrigerant pump, a recuperator, a refrigerant evaporation unit, a turbine, and a generator. According to the invention, the refrigerant evaporation unit is constructed in two stages and comprises a first heat exchanger and a second heat exchanger. The first heat exchanger is designed in particular as an evaporation unit, the second heat exchanger is designed in particular as a preheating unit.

The waste heat is used to heat and vaporize a refrigerant via the two heat exchangers of the refrigerant evaporation unit. The waste heat flows through first the first heat exchanger and then the second heat exchanger, while the refrigerant flows through first the second heat exchanger and then the first heat exchanger of the refrigerant evaporation unit. As the temperature of the waste heat as it flows through the refrigerant evaporation unit decreases, the temperature of the refrigerant increases until it finally evaporates and passes into its gaseous state of aggregation. The hot refrigerant vapor is used to drive a generator via a turbine.

Before the refrigerant is heated and vaporized via the refrigerant evaporator, it is first compressed by a factor of 15 to 25 by means of the refrigerant pump. The highly compressed refrigerant is passed through a recuperator and thereby from a Initial temperature preheated to a first preheating temperature or base heat. The green-heated highly compressed refrigerant is then passed through the second heat exchanger or the preheating of the refrigerant evaporation unit and further preheated. The highly compressed, preheated refrigerant is then passed through the first heat exchanger or the evaporation unit, while further heated and evaporated to hot refrigerant vapor. The highly compressed, hot refrigerant vapor is then expanded in a turbine and the energy released is used to drive a generator.

According to a preferred embodiment, the initial temperature of the refrigerant is between 30 ° C to 60 ° C. In this temperature range, the refrigerant has an absolute condensation pressure between about 1 bar to 1.6 bar. Before the heating and evaporation process, the refrigerant is compressed by means of a refrigerant pump to about 25 bar and then passed through a recuperator, wherein the highly compressed refrigerant is grounded to a temperature of about 100 ° C to 120 ° C. The high-pressure refrigerant, which has been heated to a temperature of 100 ° C to 120 ° C, is then passed through the preheating unit and heated to a preheating temperature of about 160 ° C. It is then passed through the evaporation unit, while heated to an evaporation temperature of about 170 ° C, where it evaporates to refrigerant vapor. The refrigerant vapor is superheated by a further 10K to approx. 180 ° C, passed to a turbine where it is expanded to the condensation pressure between 1 bar and 1.6 bar. The energy released is used to operate a generator connected to the turbine.

The waste heat to be used flows through the evaporation unit in the same direction of movement as the refrigerant and the preheating unit in opposite directions to the direction of movement of the refrigerant. In the evaporation unit, the introduced waste heat is cooled by about 200K, in particular the waste heat introduced into the evaporation unit is cooled down from an inlet temperature of about 500 ° C to an outlet temperature of about 300 ° C. Subsequently, the approximately 300 ° C warm waste heat is introduced into the preheating unit and this by another about 130K to 180K, i. cooled to about 120 ° C to 170 ° C, so that the waste heat before exiting the preheating unit has a temperature which corresponds approximately to the inlet temperature of the chimney.

The heat exchangers of the refrigerant evaporation unit are also designed as recuperators, ie the streams of waste heat and the refrigerant are spatially separated by a heat-permeable wall and flow through the Heat exchanger at the same time. In particular, the waste heat and the refrigerant flow through the first heat exchanger, ie the evaporation unit in cocurrent. The second heat exchanger, ie the preheating unit, flows through waste heat and refrigerant in countercurrent. When flowing through the hot waste heat gives off its heat to the refrigerant medium. Due to different heat capacities and adjustable flow flows, the heat transfer can be controlled and regulated so that the above-mentioned temperatures of the waste heat and the refrigerant can be achieved.

Instead of recuperators, it is also possible to use other suitable heat exchangers known to the person skilled in the art. For example, it is conceivable to use regenerators as heat exchangers, superfluous energy which is still present in the system after the superheated refrigerant vapor has been released from the turbine also being used. In particular, a regenerator can continue to use the high temperature of the refrigerant vapor of about 120 ° C to 130 ° C after relaxing. That after being expanded in the turbine, the refrigerant does not yet regain the necessary condensation temperature between 30 ° C to 60 ° C. The regenerator operates in particular with semi-indirect heat transfer, i. the initially cold highly compressed refrigerant and the still relaxing after the release of relaxed refrigerant are placed time-displaced with the heat storage in contact. The heat storage is alternately heated by the hotter medium and then cooled by the colder medium so as to transfer thermal energy from the hotter to the colder medium.

According to one embodiment of the invention, the refrigerant used is an azeotrope-based mixture based on perfluoropolyether. In known ORC modules, refrigerants based on fully halogenated fluorohydrocarbons are frequently used. Because of the resulting environmental problems, it is desirable to use fluids with little or no ozone damage potential. In addition, it is desirable to use fluids or azeotropic mixtures that do not fractionate on boiling and evaporation.

Perfluoropolyethers are fully synthetic molecules that contain only the elements fluorine, carbon and oxygen. The atomic bonding of fluorine to carbon is one of the most stable compounds of chemistry ever. This stable bond is responsible for the outstanding inert behavior, the thermal and chemical stability and a number of other special physico-chemical properties. Preferably, as solvents and heat transfer media low molecular weight, not fully fluorinated PFPEs are used, which are hydrogen-bonded on both sides.

According to a preferred embodiment, the refrigerant used is such an azeotrope mixture which contains pentafluorobutane as further component. Such a mixture boils under atmospheric pressure at 36.7 ° C. The refrigerant used has other particular advantages. Such azeotropic mixture behaves as a single compound, i. the liquid and the gaseous aggregation state each have the same composition. Furthermore, at a temperature of 50 ° C, the gas pressure is less than 3 bar, whereby a simple transport and storage of the refrigerant is possible because no pressurized gas containers must be used. This also represents an essential aspect for the safety of such a system. Furthermore, the refrigerant in the liquid state of aggregation is not highly flammable. The refrigerant is non-toxic, but has a characteristic solvent odor, so that leaks in the system are easily and quickly recognizable. The refrigerant used is chemically stable and non-aggressive to various materials, so no special containers are needed. Furthermore, the refrigerant is thermally stable during continuous operation at least up to about 190 ° C - 200 ° C.

According to one embodiment of the device, the preheating unit is arranged lying horizontally and the evaporation unit is arranged at an angle of approximately 45 ° C. to the preheating unit. Conventionally, refrigerant evaporators are arranged upright, otherwise problems in the cooling process can occur. In the embodiment according to the present invention, the waste heat and the refrigerant flow through the refrigerant evaporator from bottom to top.

In particular, the preheating unit is arranged lying horizontally in a plane above the evaporation unit. The refrigerant evaporator thus has the shape of a 90 ° to the left overturned, lying number one. The refrigerant flows through the evaporation unit upwards. The two-stage design of the refrigerant evaporator allows a compact, space-saving design of the overall device. Since the preheating unit and the evaporation unit are not arranged one above the other, but are arranged largely side by side, and since in particular the preheating unit is arranged horizontally, the height of the refrigerant evaporator can be substantially reduced. Furthermore, the two-stage structure also allows a gradual heating of the refrigerant, in particular a preheating to a temperature below the evaporation temperature and subsequent evaporation in the evaporation unit. Due to the gradation of the warming and Evaporation process, this process can also be better monitored and controlled.

The initial compression of the refrigerant takes place, for example, via a high-pressure centrifugal pump. This may in particular be a two-stage pump in order to achieve the desired high compression easily and safely. In particular, the refrigerant is compressed in a first pumping stage by a factor of about 3 to 5 and compressed in a second pumping stage again by a factor of about 3 to 5, so that a total of a compression by a factor of 9 to 25 can be achieved.

The turbine is preferably a turboexpander, which is suitable for relaxing the highly compressed and heated refrigerant vapor back to its condensation pressure of about 1 bar to 1.6 bar.

The device can furthermore be assigned a control unit which makes it possible to specifically control and / or regulate each individual process step. For example, the control unit can regulate the pump for compressing the refrigerant and thus set the desired compression of the refrigerant targeted.

Furthermore, the control unit with a temperature sensor or similar. be connected, which monitors the temperature of the refrigerant in the preheating unit. It can be provided, for example, that the control unit is coupled to an actuating means and regulated in accordance with this, the supply of waste heat in the preheating to adjust the desired outlet temperature of the refrigerant from the preheating unit. In particular, it must be ensured that the outlet temperature of the refrigerant from the preheating unit is below the evaporation temperature of the refrigerant to ensure that the refrigerant is controlled in the evaporation unit is converted into the gaseous state of aggregation while maintaining its high pressure. The control unit may be coupled to further corresponding sensors and / or regulating means in order to specifically monitor and / or control the individual process steps.

The power range of the claimed device is preferably in a power range between 20 to 50 kWel, this corresponds to a waste heat of CHPs in a range between 200 to 500 kWel. However, the specified power range may be adjusted as needed and is not intended to limit the present invention. The device according to the invention and the method according to the invention are preferably used at exhaust or waste heat temperatures of more than 200 ° C.

With the refrigerant evaporation unit constructed in two parts as an evaporation unit and as a preheating unit, the temperature of the waste heat can be greatly reduced in a simple, cost-effective, space-saving and elegant manner. In particular, the temperature of the waste heat of about 500 ° C can be reduced to 120 ° C to 170 ° C. In contrast to conventionally known devices thus no additional expensive cooling of the waste heat is necessary before it can be introduced into the chimney.

figure description

• Figur 1 zeigt eine schematische Ansicht einer Vorrichtung zur Verwertung der Abwärme von Abgasen.
• Figur 2 und Figur 3 zeigen jeweils den Weg der Abwärme A innerhalb einer Vorrichtung gemäß Figur 1.
• Figur 4 und Figur 5 zeigen jeweils den Kreislauf des Kältemittels innerhalb einer Vorrichtung gemäß Figur 1.
• Figur 6 zeigt eine schematische Ansicht einer erfindungsgemäßen Vorrichtung.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• FIG. 1 shows a schematic view of an apparatus for recycling the waste heat of exhaust gases.
• FIG. 2 and FIG. 3 each show the path of the waste heat A within a device according to FIG. 1 ,
• FIG. 4 and FIG. 5 each show the circulation of the refrigerant within a device according to FIG. 1 ,
• FIG. 6 shows a schematic view of a device according to the invention.

For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments are merely examples of how the device or method of the invention may be configured and are not an exhaustive limitation.

FIG. 1 shows a device 10 for the recovery of waste heat A from a cogeneration unit 1 or a biogas plant. 2 FIG. 2 and FIG. 3 each represent the Way 10A of the waste heat A from the CHP 1 or biogas plant 2 within the device 10 and FIG. 4 and FIG. 5 each represent the circuit 10c of the refrigerant C within the device 10.

The hot waste heat A is deflected via a bypass to a device 10 for utilization of the waste heat A. There it first flows through an evaporator 11, wherein the waste heat A is cooled from an inlet temperature T _A1 of about 500 ° C down to an outlet temperature T _A2 of about 300 ° C. Subsequently, the waste heat A is passed through a preheater 12 for the refrigerant C and thereby cooled down from an inlet temperature T _A3 of about 300 ° C to the inlet temperature T _A4 , T _K of about 120 ° C to 170 ° C of the chimney.

The refrigerant C is removed from a refrigerant reservoir 15. In the refrigerant accumulator 15, the temperature T _{C1 of} the refrigerant C is in accordance with the condensation pressure p _C1 of about 1 to 1.6 bar (depending on the outside temperature) in a range of about 30 ° C to 60 ° C. The refrigerant C is under these conditions in a liquid state. By means of a high-pressure centrifugal pump 16, the refrigerant C is compressed to a pressure p _C2 of about 25 bar and promoted. The refrigerant C flows through a recuperator 17 and is in this case heated to a temperature T _C4 of about 100 ° C to 120 ° C. It then enters the preheater 12 and is heated when passing through the preheater 12 by already slightly cooled waste heat A to a temperature T _C6 of about 160 ° C. The refrigerant C preferably has an evaporation temperature of about 170 ° C. at a pressure of about 25 bar. After flowing through the preheater 12, the temperature T _{C6 of} the refrigerant C is thus still about 10K or 10 ° C below its evaporation temperature.

Subsequently, the approximately 160 ° C hot and compressed to about 25 bar refrigerant C is passed through the evaporator 11, where it heats up to a temperature T _C7 of about 180 ° C and thereby evaporated. The vaporized refrigerant Cg is supplied to a turbine 18. In the turbine 18, the refrigerant vapor Cg relaxes to a refrigerant pressure p _C9 between 1 bar to 1.6 bar. The released energy is used to drive a generator 19 and generate electricity. The turbine 18 and the generator 19 are preferably arranged to form a compact unit. In particular, the turbine 18 and the generator 19 are arranged in a common housing.

The expanded refrigerant vapor Cg exits the turbine 18 at a temperature T _C9 of 120-130 ° C and a pressure p _C9 of about 1 bar to 1.6 bar and is in the Recuperator 17 headed. There, the refrigerant vapor Cg is cooled down to a temperature T _C3 of about 30 ° C to 60 ° C. In particular, the refrigerant vapor Cg is cooled down to approximately 10K above its condensation temperature and then passed on to the condenser 20. In the condenser 20, the refrigerant vapor Cg is liquefied and cooled down by another 5K by flowing outside air by means of a fan 21 through heat exchange tubes 22 of the condenser 20. The re-liquefied refrigerant C is collected in the refrigerant reservoir 15 and fed via the working fluid pump 16 to the circuit again.

FIG. 6 shows a schematic view of a device 10 according to the invention for the use of waste heat A. The device 10 includes in particular a refrigerant reservoir 15, a pump device 16, a refrigerant evaporator 5, a turbine 18 and a generator 19, a regenerator 17 and a condenser for the refrigerant (not shown). Preferably, a turboexpander is used as the turbine 18, which is suitable to relax the highly compressed and heated refrigerant vapor back to its condensation pressure of about 1 bar to 1.6 bar and thereby drive the generator 19. The turbine 18 and the generator 19 are preferably arranged to save space in a common housing.

The pumping device 16 for the refrigerant is, in particular, at least one high-pressure centrifugal pump. In the present embodiment, two series-connected high-pressure centrifugal pumps 16 a and 16 b are used. With the first high-pressure centrifugal pump 16a, the refrigerant is compressed to a pressure of about 6 bar to 10 bar. The pre-compressed refrigerant is then compressed in the second high pressure centrifugal pump 16b to the working pressure of about 25 bar.

The refrigerant evaporator 5 is constructed in two stages and consists of a horizontal preheater 12 and an evaporator 11, which is arranged at an angle of approximately 45 ° to the preheater 12. As in the FIGS. 6 9, the refrigerant evaporator 5 thus shows the shape of an overturned number one, the normally long vertical line being formed by the preheater 12 arranged horizontally in an upper level and the slope normally bent down to the left below being formed by the evaporator 11 , The refrigerant evaporator 5 is thus designed to be particularly compact and space-saving, so that the entire apparatus 10 has a particularly compact construction. The refrigerant first flows through the preheater 12 in a first substantially horizontal direction of movement, in opposite directions to the direction of movement of the waste heat A. Subsequently, the refrigerant C is diverted so that it flows rectified with the waste heat A the evaporator 11 in an obliquely upward second direction of movement.

The device 10 further comprises a cabinet 25. This contains the entire control for the device. In particular, the individual process steps are controlled and regulated via the controller.

The invention has been described with reference to a preferred embodiment. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

LIST OF REFERENCE NUMBERS

1

CHP (combined heat and power plant)

2

biogas plant

5

Refrigerant evaporator

10

Device for using exhaust waste heat

10A

Way of the exhaust gas

10c

Refrigerant circulation

11

Evaporator

12

preheater

15

Refrigerant storage

16

pump

17

recuperator

18

turbine

19

generator

20

capacitor

21

fan

22

Heat exchange tube

25

switch cabinet

A

exhaust

C

refrigerant

cg

Refrigerant vapor

pc

Refrigerant pressure

T _A

Exhaust gas temperature

tc

Refrigerant temperature

T _K

Chimney temperature

Claims (15)

A method for generating electric power from waste heat (A), wherein the waste heat (A) has a temperature (T _A ) of ≥ 200 ° C and a refrigerant evaporation unit (5) consisting of a first heat exchanger, in particular an evaporation unit (11), and a second heat exchanger, in particular a preheating unit (12), flows through, wherein • the refrigerant used (C) is first compressed by a factor of 15 to 25; The highly compressed refrigerant (C) is passed through a recuperator (17) and thereby becomes more thoroughly heated, • the highly compressed, green-heated refrigerant (C) is passed through the second heat exchanger and preheated; • passing the highly compressed and preheated refrigerant (C) through the first heat exchanger, continuing to heat and evaporate to refrigerant vapor (Cg); • wherein the heated refrigerant vapor (Cg) is subsequently expanded in a turbine (18) and • wherein the energy released thereby is used to drive a generator (19). The method of claim 1, wherein • the refrigerant (C) has a condensation pressure between 1 to 1.6 bar; The refrigerant (C) is compressed by means of a refrigerant pump (16) to a pressure (p _C2 ) of approximately 25 bar, • the refrigerant (C) compressed to approx. 25 bar is passed through a recuperator (17) and, in the process, is heated to a temperature (T _C4 ) of approx. 100 ° C to 120 ° C, • the highly compressed refrigerant (C) is passed through the second heat exchanger designed as a preheating unit (12) and heated to a preheating temperature (T _C6 ) of about 160 ° C; The highly compressed and preheated refrigerant (C) is passed through the first heat exchanger designed as evaporation unit (11), heated to an evaporation temperature of approximately 180 ° C. (T _C7 ) and evaporated to refrigerant vapor (Cg); In which the heated refrigerant vapor (Cg) is subsequently expanded in a turbine (18) designed as a turboexpander to the condensation pressure (p _C9 ) between 1 to 1.6 bar, and • wherein the energy released thereby is used to drive a generator (19). Method according to claim 1 or 2, wherein the refrigerant vapor (Cg) emerging from the turbine (18) has a temperature (T _C9 ) of approximately 120 ° C to 130 ° C, the refrigerant vapor (Cg) being fed to the recuperator (17 ) and wherein the temperature (T _C9 ) of the hot and relaxed refrigerant vapor (Cg) is used to cool the liquid high-pressure refrigerant (C) from a temperature (T _C3 ) of about 30 ° C to 60 ° C preheat to a base heat (T _C4 ) of approx. 100 ° C to 120 ° C Method according to one of claims 1 to 3, wherein the waste heat to be used (A) flows through the evaporation unit (11) in the same direction to the direction of movement of the refrigerant (C) and the preheating unit (12) flows in opposite directions to the direction of movement of the refrigerant (C) and wherein the waste heat (A) in the evaporation unit (11) is cooled by about 200K, in particular wherein the waste heat (A) introduced into the evaporation unit (11) has an inlet temperature (T _A1 ) of about 500 ° C and an outlet temperature (T _A2 ) of 300 ° C, and wherein the waste heat (A) is then cooled in the preheating unit (12) by about 130K to 180K, in particular wherein the in the preheating unit (12) forwarded waste heat (A) an inlet temperature (T _A3 ) of about 300 ° C and an initial temperature (T _A4 ) of about 120 ° C to about 170 ° C, which corresponds approximately to the inlet temperature of the chimney (T _K ). Method according to one of the preceding claims, wherein as refrigerant (C) an azeotropic mixture based on perfluoropolyether (PFPE) is used. A method according to claim 5, wherein the azeotrope mixture used as the refrigerant (C) comprises pentafluorobutane. Device for generating electric power from waste heat (A) with a refrigerant reservoir (15), a refrigerant pump (16), a recuperator (17), a refrigerant evaporation unit (5), a turbine (18) and a generator (19), characterized in that the refrigerant evaporation unit (5) is constructed in two stages and consists of a first heat exchanger and a second heat exchanger, in particular of an evaporation unit (11) and a preheating unit (12). Apparatus according to claim 7, wherein the preheating unit (12) is arranged lying horizontally and wherein the evaporation unit (11) is arranged at an angle of approximately 45 ° C to the preheating unit (12). Apparatus according to claim 8, wherein the preheating unit (12) is arranged horizontally in a plane above the evaporation unit (11) and wherein the evaporation unit (11) is arranged at an angle of about 45 ° C to the preheating unit (12), so that the refrigerant (C) flows through the evaporation unit (11) directed downwards. Device according to one of claims 7 to 9, wherein the refrigerant pump (16) is a high-pressure centrifugal pump for compressing the refrigerant (C) by a factor of 15 to 25. Device according to one of claims 7 to 9, wherein the refrigerant pump (16) as a one- or two-stage pump (16a, 16b) for compressing the refrigerant (C) by a factor of 15 to 25 is formed. Device according to one of claims 7 to 11, wherein the refrigerant (C) is an azeotropic mixture based on perfluoropolyether (PFPE). Apparatus according to claim 12, wherein the azeotropic mixture used as refrigerant (C) comprises pentafluorobutane. Device according to one of claims 7 to 13, wherein the turbine (18) is a turboexpander, through which the highly compressed and heated refrigerant vapor (Cg) to a pressure between 1 bar to 2 bar, preferably between 1 bar to 1.6 bar, is relaxing Apparatus for generating waste electrical energy (A) according to a method according to any one of claims 1 to 6.

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