WO2016155705A1

WO2016155705A1 - Device for using exergy

Info

Publication number: WO2016155705A1
Application number: PCT/DE2016/100144
Authority: WO
Inventors: Jörg Nickl
Original assignee: Technische Universität Dresden
Priority date: 2015-03-27
Filing date: 2016-03-24
Publication date: 2016-10-06
Also published as: DE102015104769A1

Abstract

The invention relates to a device (1) for using exergy, in particular a steam power plant designed for a steam power process, comprising a closed circuit (2), which is surrounded by air as an atmosphere having an ambient pressure (p_u) and in which a working medium circulates. In the flow direction of the working medium, the circuit (2) has an evaporator (3) for evaporating the working medium at an evaporation pressure (p_v), an expansion device (6) for expanding the working medium, mechanical work thus being performed, a condenser (11) for condensing the working medium at a condensation pressure (p_K), a reservoir (14), and a feed pump (17) for conveying the working medium to the evaporator (3). In addition, a component for conveying the working medium into the reservoir (14) is formed after the condenser (11) in the flow direction of the working medium. Dynamic seals are arranged between the working medium within a region of the circuit (2) operated at the level of the condensation pressure (p_K) and the surroundings, which dynamic seals are two-stage dynamic seals and are designed in such a way that the air surrounding the device (1) lies against the dynamic seals as a sealing gas, wherein the ambient pressure (p_u) as the pressure of the air is greater than the lowest pressure of the working medium in the circuit (2), in particular the condensation pressure (p_K) of the working medium.

Description

Device for using the exergy

The invention relates to a device for the use of exergy, in particular a trained for a steam power steam plant, with a closed circuit in which circulates a working fluid. The circuit is surrounded by air at an ambient pressure and has in the direction of flow of the working medium an evaporator, an expansion device for relaxing the working medium while performing mechanical work, a condenser, a reservoir and a feed pump for conveying the working fluid to the evaporator. After the condenser also a component for conveying the working medium is formed in the reservoir. Steam power plants known from the prior art are used in conjunction with motor vehicles, in particular motor vehicles driven by internal combustion engines, or stationary devices, such as power plants, for generating predominantly electrical energy. The Dam pfkraf tan läge is acted upon with the hot exhaust gases of the internal combustion engine of the motor vehicle or the gas engines or gas turbines, so that the heat of the exhaust gas is used to generate steam. The steam generated by cooling the exhaust gases or burning fossil fuels is expanded as it flows through an expansion machine to perform mechanical work. By means of the steam power plants thus the energy of the fuels or the exhaust gases is used and with the energy provided during the expansion of the steam, a generator or other component, such as a compressor driven. Conventional steam power plants are formed from a closed circuit of a working medium, in which a working medium circulates. The circuit has an evaporator for evaporating the working medium, a Expansion machine for relaxation of the working medium while performing mechanical work, a condenser for condensing the working fluid, a reservoir for storing the working fluid and thus to compensate for volume fluctuations within the circuit and a feed pump for conveying the working fluid, wherein the components in the order specified by the working fluid be charged.

From DE 10 2012 006 142 A1 discloses a Dam pfkraftan would be for a motor vehicle or a stationary device, in particular for a small power plant or for a compressor station for the production of oil or gas out. The steam power plant has a closed circuit of a working medium with the specified components. The feed pump is preceded by a pressure booster pump in the direction of flow of the working medium in order to increase the pressure of the working medium at the inlet to the feed pump and to keep it constant. With the upstream booster pump cavitation in the feed pump can be avoided. Between the outlet of the condenser and the inlet of the reservoir, a condensation pump for sucking working fluid from the condenser is also formed so that the dam pfkraftan is operable with a lower and substantially constant condensation pressure.

DE 10 2012 021 326 A1 discloses a method for generating electrical energy and a power generation plant. The method for generating electrical energy for a grid network with alternating current comprises the steps of: burning a natural gas, biogas, pit gas or landfill gas with an internal combustion engine, which generates an exhaust gas stream, for driving a first electric generator or another working machine, supplying an evaporator of a Circulation of a steam power plant with waste heat from the exhaust gas stream to evaporate the working medium, supplying the vaporous working medium from the evaporator in an expansion device for expanding the steam and generating mechanical energy, driving the first or a second electric generator by means of the expansion device and feeding at least a portion of the electrical energy generated by the electric generators in the power grid. The circulation of the working medium of the plant has in the flow direction of the working medium after the evaporator to a bypass, which branches off in front of the expansion device and after the expansion device, in particular in front of the condenser, re-opens.

The known from the prior art systems are formed with elaborate sealing systems to prevent the escape of working fluid from the circulation. When using water as a working medium, the escape of working fluid from the circuit can lead to fogging of components, which could cause electrical disturbances of the system, for example.

The object of the invention is to provide a device for the efficient use of exergy, in particular from exhaust gases. The device should be simple and allow automatic, safe operation with little effort for maintenance. For safe operation of the device also includes a leak-free training with respect to the working medium. The device should cause low manufacturing costs, have a long life and high reliability.

The object is achieved by the subject matters with the features of the independent claims. Further developments are specified in the dependent claims.

The object is achieved by a device according to the invention for the use of Exergy, especially one designed for a steam power process Dam pfkraf tan would be solved with a closed circuit. The circuit is surrounded by an atmosphere consisting of air at ambient pressure. Within the cycle circulates a working medium. The circuit has in the flow direction of the working medium, an evaporator for evaporating the working medium at an evaporation pressure, an expansion device for relaxing the working medium while performing mechanical work, a condenser for condensing the working fluid at a condensation pressure, a reservoir and a feed pump for conveying the working fluid to the evaporator , In the flow direction of the working medium after the condenser, a component for conveying the working medium is also formed in the reservoir. According to the concept of the invention, dynamic seals are arranged between the working medium within a region of the circuit operated at the level of the condensation pressure and the surroundings, which are designed in two stages such that the air surrounding the device bears against the dynamic seals as sealing gas. In this case, the ambient pressure as the pressure of the air is greater than the lowest pressure of the working medium within the device.

The condensation pressure is the lowest pressure level of the working medium within the circuit, wherein advantageously water is used as the working medium. The dynamic seals are in particular formed on components of the expansion device.

According to a preferred embodiment of the invention arranged in the flow direction of the working medium between the condenser and the reservoir component for conveying the working medium in the reservoir is designed as ejector. The ejector for sucking off the working medium as well as the air from the condenser, which has penetrated the circuit as sealing gas through the dynamic seals, is the environment also connected to a backing pump for conveying a mass flow of the working medium as a propulsion jet of the ejector. The ejector thus promotes in connection with the fore pump working fluid and air in the reservoir.

The backing pump is advantageously formed connected to an outlet of the reservoir and arranged between the reservoir and the feed pump for conveying a mass flow of the working fluid to the feed pump.

The backing pump thus serves to convey the propulsion jet of the ejector as a first mass flow of the working medium and a second mass flow of the working medium to the subsequent feed pump.

According to a further preferred embodiment of the invention, the reservoir on a degassing line as a connection with the environment. The degassing line is in an upper, filled with saturated air region of the reservoir opening, steadily rising and cooled designed such that vaporous working medium condenses as it flows through the degassing at least for the most part and flows back down into the reservoir and the device penetrated air upwards can escape into the environment.

According to a development of the invention, an arrangement for the return of lubricant is arranged in the flow direction of the working medium after the expansion device. The arrangement comprises a separator designed as a cyclone for separating working medium and lubricant and a collector for the lubricant. The collector is arranged in the direction of gravity below the separator. The collector is preferably formed with a substantially outwardly inwardly directed channel guide, so that in the center there is a liquid stratification of working fluid and lubricant. The collector advantageously has a bottom, wherein in a central region of the collector at the bottom of a valve for sucking accumulated in the accumulator working fluid is formed. The valve is preferably coupled via a connecting element with a float, with which the valve is opened at a certain level within the collector.

According to an advantageous embodiment of the invention, the collector is connected via a line for sucking working fluid from the collector and for conveying the working fluid into the reservoir with the ejector. The line preferably opens parallel to the connection of the connection to the capacitor in the ejector.

A further advantageous embodiment of the invention is that the collector is formed connected via a line for sucking lubricant from the collector and for conveying the lubricant to the expansion device with a metering pump.

The line preferably projects into the volume enclosed by the collector and ends above the level of the working medium and below the level of the collector formed in the float of the valve for sucking accumulated in the accumulator working fluid to suck the floating on the working fluid lubricant.

According to a development of the invention, the expansion device is designed as a crosshead machine with a crosshead, a piston rod and a piston. In this case, the piston has an inner cone on the crank side and a conical piston nut corresponding to the inner cone for setting and varying an axial piston clearance in the direction of the piston rod. The piston is preferably designed as a double-acting piston with two vapor-side piston bodies with piston rings and an intermediate piece as a double T-piston. The intermediate piece advantageously has approximately half the diameter of the piston body. A further preferred embodiment of the invention is that the piston rod is arranged guided through the housing of the expansion device delimiting a working space to the surroundings of the device. Here, a rod seal is arranged between the piston rod and the housing, which has a sealing segment package with an outer non-contact labyrinth seal and at least one inner contacting segment seal.

Under the outer or outer side is the side in the direction of the environment and under the inside or inner side is the side in the direction of the working space to understand.

Between the outer non-contact labyrinth seal and the inner contacting segment seal, a fluid channel is advantageously formed as a connection to a region of low pressure of the circuit.

The region of low pressure of the circulation is in this case the region which is preferably acted upon by the condensation pressure of the working medium, the condensation pressure being lower than the pressure of the ambient air used as sealing gas. The sealing segment package of the rod seal is advantageous with a plate spring in the direction of the piston rod to the working space out, that is arranged inwardly, axially braced and serves to compensate for manufacturing tolerances.

The labyrinth seal is preferably with a corrugated spring in the direction of the piston rod towards the environment, that is outwardly, axially biased. The force of the clamping of the sealing segment package of the rod seal with the diaphragm spring is greater than the maximum compressive force and thereby many times higher than the force of the bias of the labyrinth seal with the wave spring, since only the pressure force to the environment is overcome. According to an advantageous embodiment of the invention, the expansion device has at least one working space, which is connected to a pressurized cylinder safety valve. The Cylinder safety valve is as a spill valve a connection from the working space to an outlet of the expansion device closed or apparently formed and acted upon by the inlet pressure and configured to open a connection to the outlet of the expansion device when a certain pressure of the working medium within the working space is exceeded. During operation of the device, the inlet pressure substantially corresponds to the evaporation pressure of the working medium. The expansion device is preferably formed in a DC design with a piston valve with valve bodies with circular cylindrical cross-sections and an inner inflow and a piston rod with kreiszylinderförmigem cross-section. The advantageous trained with piston rings slider body and the piston rod have the same diameter.

A crank-side slider body is out without paragraph as a slide rod out of the housing, the piston rings replace a touching segment seal. According to a development of the invention, a valve box formed as a combination of a shut-off valve, an overflow valve and a pressure relief valve is arranged between the evaporator and the expansion device. The shut-off valve and the overflow valve are formed combined in a three-way valve.

A further advantageous embodiment of the invention is that the valve box has a rotary valve chamber with a circular cylindrical cross-section, an outlet chamber and a spring chamber. The rotary valve chamber is formed with connections to the evaporator, to the expansion device and to a separator and the outlet space with a connection to the condenser or a separator. Within the rotary valve space, a rotary valve is preferably arranged, which is connected to a drive element rotatable by an angle of 90 ° and is mounted radially movable in a housing passage formed between the rotary valve chamber and the outlet space.

An arranged between the rotary valve chamber and the outlet chamber housing passage is advantageously formed conically widened on the side of the outlet space, wherein a spherical segment-shaped valve seat rests as part of the drive element movable sealingly on the conical extension. The drive element is mounted so as to move axially against a spring at a certain overpressure of the working medium within the rotary valve space, so that the valve seat lifts off the conical extension and releases a gap as an opening between the rotary valve chamber and the outlet.

According to a further preferred embodiment of the invention, the three-way valve is formed with a Dampfübertritt as a connection to the condenser or a separator and configured to open in an arrangement for closing the connection to the expansion device, the steam exceeded.

The advantageous embodiment of the invention enables the use of the device in conjunction with an internal combustion engine of a motor vehicle or a ship or a CHP system and exhaust gases of the internal combustion engine as a heat source for evaporation of the working fluid in the evaporator.

The device according to the invention for the efficient use of exergy, in particular from exhaust gases, has in summary various advantages:

- automatic, safe operation with little effort for maintenance,

Leakage-free training with respect to the working medium with air as a sealing gas, that is in particular no escape of vaporous working medium, - Separate systems for lubrication of the working chamber and the engine of the expansion device as well

- Thermal separation of the working space and the engine of the expansion device.

Further details, features and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

Fig. 1: Device for the use of exergy in the form of a

Steam power process,

2a to 2e: arrangement of separator and collector of lubricant with valve box,

Fig. 3a, 3b: Valve box as a combination of a shut-off valve and a

Overflow valve trained three-way valve and a pressure relief valve with a closed line to the expansion device,

3c: position of the rotary valve of the three-way valve with open line to the expansion device,

FIG. 4a: expansion device with double-acting piston, FIG.

Piston valves and cylinder safety valves,

4b: double-acting piston with piston rings,

Fig. 4c: two-stage seal of the piston rod and

Fig. 5: Integration of the steam power process in a CHP system.

In Fig. 1, a device 1 for the use of exergy, for example from the exhaust of an internal combustion engine, a fired boiler or a gas turbine, shown in the form of a steam power process. The steam power process is illustrated by means of a steam cycle, also referred to as circuit 2 of the working medium. The exhaust gas flows in the flow direction 4 through an evaporator 3 of the circuit 2, wherein waste heat of the exhaust gas is transferred to the working medium for complete evaporation with or without subsequent overheating of the circulating in the closed circuit 2 working fluid in the evaporator 3. The circuit 2, the evaporator 3 in the flow direction of the working medium below a designated valve box 5 arrangement of valves, an expansion device 6 for expanding the steam while performing mechanical work and an assembly 8 for the return of lubricant. The assembly 8 is formed of a separator 9 and a collector 10 for separating lubricant and working fluid and for collecting the lubricant.

The evaporator 3 and the valve box 5 are connected to each other via a line L6. A line L7 connects the valve box 5 with the expansion device 6, while the expansion device 6 and the separator 9 are coupled together via a line L5.

Between the collector 10 of the lubricant and the expansion device 6, a line L4 for returning the lubricant to the expansion device 6 is also formed. Within the line L4 a metering pump 18 is arranged to convey the lubricant from the collector 10 to the expansion device 6.

In the expansion device 6, which is preferably in the form of a piston engine, the vapor of the working medium is released while performing mechanical work, an electrical generator 7 being driven by the mechanical work.

The arrangement 8 for returning the lubricant is connected in the region of the separator 9 via a line L2 with a condenser 11 for condensing the vapor of the working medium. The condenser 11 is acted upon by coolant, which flows through the condenser 11 in the flow direction 12. The condensation heat of the working medium is transferred to the coolant.

The condenser 11 is in the flow direction of the working medium Reservoir 14 for storing the working fluid and thus to compensate for volume fluctuations within the circuit 2 downstream. The reservoir 14 is referred to in the operation of the circuit 2 with water as the working medium as a feedwater tank.

Between the outlet from the condenser 11 and the inlet into the storage container 14, a device designed as an ejector 13 for conveying the working medium from the condenser 11 into the storage container 14 is also arranged. Thus, the circuit 2 can be operated with a substantially constant condensation pressure p _K.

The pumping action of the ejector 13 is generated by a fluid jet of the working medium generated by a forepump 16, also referred to as a propulsion jet, which sucks, accelerates and conveys the condensate by momentum exchange from the condenser 11. With the suction, a negative pressure is generated in the condenser 11. The condensation pressure p _K is advantageously lower than the ambient pressure pu, that is less than the pressure of the air surrounding the device 1. The ejector 13 has a simple construction, is formed without moving parts and thus very robust and low maintenance.

The propellant jet generated by the fore pump 16 is used in addition to the suction and conveying the condensed working medium from the condenser 11 in the reservoir 14 for sucking and conveying accumulated in the collector 10 working medium. The collector 10 is connected to the ejector 13 at the bottom, preferably at the bottom, via a line L3. The line L3 is formed with a valve 19, which is controlled by a float 10 arranged in the collector. When the level in the collector 10 reaches a certain height, the valve 19 is opened by means of the float and the ejector 13 sucks the accumulated at the bottom of the collector 10 working fluid until the level has dropped so far that the valve 19 is closed by the float becomes.

The backing pump 16, which has a first partial mass flow of the working medium as a propulsion jet from the reservoir 14 to the ejector 13 promotes, is also upstream of the feed pump 17 in the flow direction of the working medium to promote a second partial mass flow of the working fluid to the feed pump 17 and to increase the pressure of the working fluid at the inlet to the feed pump 17. The pre-pump 16 upstream of the feed pump 17 serves to prevent cavitation in the feed pump 17. The pressure difference to be applied by the feed pump 17 for conveying the working medium into the evaporator 3 is reduced. The feed pump 17 is preferably designed as a reciprocating pump.

The evaporator 3 has the largest space requirement as the component with the largest volume of the device 1 and is designed as a cross-countercurrent heat exchanger with flowing in the flow direction 4 exhaust stream and to substantially opposite flowing mass flow of the working medium. The exhaust gas is thereby passed around parallel and meandering arranged tubes, while the working medium of the circuit 2 flows in the tubes. This is advantageous for a low exhaust back pressure generated, which for example reduces the power of an internal combustion engine. On the other hand, the evaporator 3 has a low internal volume, that is to say a small proportion of liquid working medium as an energy store, which has a particularly favorable effect, in particular when starting and switching off the device 1 and with regard to test specifications. Furthermore, the construction is very low in tension with respect to different thermal expansions.

The downstream in the direction of flow of the working medium the evaporator 3 arranged valve box 5 combines the arrangement of a shut-off valve, a spill valve and a pressure relief valve, the shut-off, for example, load at the generator 7, the overflow during startup or pressure relief at exhaust-shut off evaporator 3 and the pressure limit provided as an additional safety feature. While the connection between the evaporator 3 and the valve box 5 and the expansion device 6 is formed as a long insulated line L6 for the steam, the outlet of the expansion device 6 via a short line L5 with the acting as a pulsation damper assembly 8 for the return of the lubricant Separator 9 and collector 10 connected.

FIGS. 2a to 2e show the arrangement 8 of separator 9 and collector 10 of the lubricant in various views, with connected valve box 5 according to FIG. 2a.

The separator 9 has an upper chamber 30 and a lower chamber 31, which are separated by a partition 32 from each other. The chambers 30, 31 are connected to one another by means of an overflow connection 33 for passing through vaporous working medium, the vaporous working medium being flowed over from the lower chamber 31 into the upper chamber 30 and being discharged through the line L2 to the condenser 11. The overflow connection 33 between the lower chamber 31 and the upper chamber 30 is bounded on the inside by a central tube 34 and on the outside by a coaxial to the central tube 34 arranged tubular element 45. The central tube 34 extends from a filler neck 35 of the lubricant disposed on the lid of the separator 9 to the bottom of the collector 10.

The separator 9 is formed in the upper region of the lower chamber 31 with the tangentially arranged line L5 as connection between the inlet into the separator 9 and the outlet of the expansion device 6 to the lubricant, in particular oil, and partly liquid working medium from the vaporous working medium separate. The separator 9, which is designed as a large-volume cyclone, at the same time represents a large capacity for the outlet of the expansion device 6 arranged in the immediate vicinity as a pulsation damper.

The flowing through the line L5 and the inlet into the separator 9 mixture of vaporous and liquid working medium and Lubricant is separated, wherein the vaporous working medium is passed through the overflow 33 into the upper chamber of the separator 9 and the mixture of liquid working medium and lubricant along the wall of the separator 9 down into the collector 10.

Trained as a cone intermediate bottom 38 has a radial clearance and thus a gap to the wall of the separator 9. The intermediate bottom 38 prevents on the one hand a large-area contact of the working medium with the already deposited lubricant in the collector 10 and on the other hand allows a simple inflow of liquid working fluid on the wall in the collector 10. The formed in the center of the assembly and at the top of the separator 9 with The central tube 34 also has pressure compensation openings 36, 37, which on the steam side between the level of the maximum level in the collector 10 and the intermediate bottom 38 and the condensate side are formed at the bottom of the assembly 8.

The collector 10 located in the direction of gravity below the separator 9 has partition walls 39 arranged concentrically around the central tube 34 and sufficiently sealed to the bottom. The bulkheads 39 provide for the mixture of liquid working fluid and lubricant a time-long flow path from the outside into the center to safely separate due to the difference in density, the lubricant from the working fluid.

Within the central tube 34 of the collector 10, the float 40 is installed axially movable and connected via a vertically arranged connecting element 41 with the valve 19 designed in particular as a needle valve. The float 40 controls the opening and closing of the valve 19. The connecting element 41 is rod-shaped.

The liquid working medium with a greater density than the lubricant settles when flowing along the one channel forming bulkhead walls 39 substantially from the outside into the center of the collector 10 in the lower region of the collector 10 from the central tube 34, so that a liquid layer is formed in the center. With the accumulating liquid working fluid and the lubricant, the float 40 is raised, being opened via the connected to the float 40, arranged at the bottom of the collector 10 valve 19 and an excessive amount of liquid working fluid through the bottom of the collector 10 and the line L3 is sucked in the direction of the ejector 13. During the discharge of the liquid working fluid, the float 40 is lowered and at a predetermined filling level in the collector 10, the valve 19 is closed.

The lubricant separated from the liquid working medium is preferably aspirated as superheated steam cylinder oil by means of the metering pump 18 arranged in the line L4 below the level of the float 40 and supplied to the expansion device 6, preferably the valve chamber, as inlet of the working medium into the expansion device 6. The line L4 extends on the suction side of the metering pump 18 through the bottom of the collector 10 to just below the predetermined, minimum level within the collector 10th

A check valve arranged in front of the inlet into the valve chamber prevents accidental backflow of steam into the collector 10.

To set the predetermined maximum level within the collector 10, the collector 10 is filled up to the visible with a arranged on the level of the float 40 sight glass 42 level indicator with pure lubricant. The filling level results from the predetermined amount of lubricant to be introduced into the device 1. Lifting the float 40 above the predetermined level may thus be caused only by the accumulation of liquid working fluid during operation, which is dissipated by opening the valve 19 to the ejector 13.

The according to FIG. 2a via the line L1 and the steam transfer step 44, which each open into the first chamber 30 of the separator 9, with the arrangement 8 connected valve box 5 also has a pressure sensor 43 for determining the pressure p at the outlet of the vapor from the evaporator 3. The line L1 is coupled to a safety valve.

From FIGS. 3 a and 3 b, a valve box 5 emerges as a combination of the pressure limiting valve 50 designed as a safety valve and a three-way valve 51 formed from a shut-off valve and an overflow valve, in particular the three-way valve 51 in FIG is shown in sectional view. The valve box 5 has a cylindrical rotary valve chamber 58 with connections to the evaporator 3 and to the expansion device 6, an outlet chamber 56 with a connection operated to the condensation pressure p _K to the separator 9 or to the condenser 11 and a spring chamber 54.

The valve box 5 is formed in the region of the three-way valve 51 with a rotary valve 57 for shutting off the entry of the steam into the expansion device 6, for example in case of load drop of the generator 7, as shown in FIGS. 3a and 3b. The load drop of the generator 7 is registered by a sudden change, that is, an increase, in the rotational speed n.

The three-way valve 51 has an inlet and two outlets in the area of the rotary valve chamber 58. In the inlet opens the extending between the evaporator 3 and the valve box 5 line L6. The steam of the working medium conducted from the evaporator 6 to the valve box 5 is guided, depending on the position of the rotary valve 57, through the steam transfer step 44 to the separator 9 or via the line L7 to the expansion device 6. The steam transfer step 44 and the line L7 are each connected to an outlet of the three-way valve 51 and arranged at an angle of 90 ° to each other. Depending on the need and operating state of the device 1, for example during the closing of the outlet to the line L7 and thus to the expansion device 6, a small mass flow of vaporous working medium in the direction of the separator 9 is released by the outlet connected to the steam transfer step 44. When the outlet to the line L7 is open, the outlet to the steam transfer step 44 is closed. With the open outlet to the steam transfer step 44, a first wet steam can be removed both from the evaporator 3 and from the rotary valve chamber 58 of the three-way valve 51, allowing a drier start of the expansion device 6. In addition, a vapor flow is always ensured in the case of a shut-off start of the device 1 at the temperature measuring point at the outlet of the working medium from the evaporator 3.

Fig. 3c shows the position of the rotary valve 57 of the three-way valve 51 with the line L7 to the expansion device 6 open. The vapor flowing from the evaporator 3 through the line L6 and the inlet in the three-way valve 51 of the valve box 5 is the Outlet and forwarded through the line L7 to the expansion device 6. The outlet to the steam transfer step 44 is closed. The rotary valve 57 designed for a rotary movement at an angle of 90 ° is arranged inside the rotary valve chamber 58 and has a radial play for sealing to form a drive spindle 52 designed as a drive spindle. The drive element 52 of the rotary valve 57 is also designed as a spring-loaded pressure limiting valve 50 with axial play, wherein in an axial movement of the drive element 52 within a formed between the rotary valve chamber 58 and the outlet chamber 56 housing passage radial guidance is ensured.

The spherical segment-shaped valve disk lies as a valve seat 55 sealingly in the conically formed between the rotary valve chamber 58 and the outlet chamber 56 to the housing bushing. The closed in the direction of the rotary valve 57 outlet 56 of the valve box 5 is connected via the line L1 to the separator 9 and the condenser 11.

In the direction of the rotary valve 57, the spring space 54 adjoins above the boundary of the outlet space 56, the wall of which has a plurality of openings 59 connected to the surroundings of the device 1. Due to the small pressure difference between the ambient pressure pu and the Condensation pressure p _K is between the spring chamber 54 and the outlet space 56, that is, between the boundary and the drive element 52 to provide no additional and complicated to be constructed seal.

The drive element 52 is loaded by means disposed within the spring chamber 54 spring 53, the spring 53, the drive element 52 in the axial direction with the valve seat 55 presses against the housing passage. The spring 53 is designed such that the drive element 52 moves at an applied within the rotary valve chamber 58, predetermined pressure of the working medium, also referred to as overpressure, in the axial direction against the spring force and thus the valve seat 55 is opened, so that the working fluid through the housing bushing is passed into the outlet space 56 and through the line L1 to the separator 9.

The line L1 and the steam 44 are thus formed as bypasses around the expansion device 6, which branch off in the circuit 2 of the working medium of the device 1 in the flow direction of the working medium after the evaporator 3 and before the expansion device 6 and after the expansion device 6, in particular before Capacitor 11, re-open. The vaporized working medium is consequently conveyed via the valve box 5 either into the expansion device 6 or via the line L1 or the steam transfer step 44 as bypasses around the expansion device 6.

The valve box 5 is directly and rigidly coupled to the separator 9, since in the case of the response of the pressure relief valve 50, a large pulse is generated.

The expansion device 6 arranged downstream of the valve box 5 in the flow direction of the working medium in the circuit 2 downstream of the evaporator 3 is designed as a crosshead machine with separate lubricant systems for the engine and the cylinder, with an inlet 60 for the working medium and the lubricant and with cylinder safety valves 61. As shown in Fig. 4a, the expansion device 6 has a double-acting piston 62 with a piston rod 63, a piston slide 70 for the inlet 60 of the working medium, an outlet connected to the line L5 to the separator 9 on the cylinder as well as pressurized relief valves cylindrical safety valves 61 , The expansion device 6 is operated as an expansion machine in the DC principle, according to type stump with spool 70 and internal inflow, which is advantageous in terms of low cooling losses during the flow of the working medium into the expansion device 6. The pressure of the working medium at the outlet from the cylinder, which corresponds to the condensation pressure p _{K of} the device 1, is always lower than the ambient pressure pu of the air surrounding the device 1, so that the ambient air is used as the outer sealing gas and the low pressure region of the device 1 operated at the pressure level of the condensation. The pressure of the working medium at the inlet 60 of the expansion device 6, that is to say the inlet pressure, corresponds in particular during operation of the device 1 substantially to the evaporation pressure p _v . The flowing through the line L7 in the expansion device 6 working fluid is passed over the slide chamber 73 alternately on the work spaces.

Both the expansion device 6 with the cylindrical safety valves 61 designed as pressurized overflow valves and the valve box 5 can each likewise be used in steam power processes in which the surrounding air, in particular on dynamic seals, is not used as a sealing gas. Consequently, the expansion device 6 with the cylinder safety valves 61 as well as the valve box 5 can be used in steam power processes without air as a sealing gas.

The double-acting piston 62 is formed of two vapor-side piston bodies and an intermediate piece as a double T-piston. The intermediate piece has approximately half the diameter of the vapor-side piston body. The vapor-side piston bodies are each provided with piston rings for sealing the working spaces in combination with the cylinder, which is also shown in FIG. 4b evident.

The crank-side piston body of the piston 62 has an inner cone formed in the piston body. Within the inner cone a conical piston nut 64 corresponding to the inner cone is arranged for adjusting and varying the axial piston clearance. The piston 62 is braced on the cover-side piston body by means of a rod nut 65 with the piston rod 63.

The rod seal 66a of the piston rod 63 and the rod seal 66b of the crank-side slider body 71 of the spool valve 70 are referred to as two-stage seals with Zwischenabsaugung in the direction of the capacitor

11 trained. 4c shows a two-stage seal of the piston rod 63.

The slider body 71, 72 have the same diameter as the

Piston rod 63 on. According to an alternative embodiment, the crank-side slider body 71 is guided outwardly without a shoulder as a slide rod, wherein instead of an inner contacting segment seal

Piston rings are formed.

From the environment in the expansion device 6 in the region of the rod seals 66a, 66b penetrating air is passed as an air-working medium mixture through the suction ports 67a, 67b via connections to the line L5 through the separator 9 to the condenser 11 and shown in FIG Ejector 13 is conveyed into the reservoir 14. Furthermore, in the region of the cover-side slide body 72 of the piston slide 70 of the inlet 60, a suction connection 67c is formed in order to guide the leakage of the working medium via a connection to the line L5 and through the separator 9 to the condenser 11.

The conveyed through the ejector 13 with the working fluid into the reservoir 14 air is discharged through a degassing line 1 5 from the reservoir 14 into the environment, which is shown in Fig. 1. The continuously rising, for example, spirally, and cooled design degassing line 15 is arranged such that the vapor present working medium when flowing through the degassing 15 at least for the most part condenses and flows back into the reservoir 14, while the air has penetrated into the device 1 escapes up into the environment.

The device 1 is thus formed with air as a sealing gas in such a way that no working medium escape and when using water as a working medium no fogging of components can occur, which could lead to electrical interference of the device 1.

The rod seal 66a of the piston rod 63 has internal, on the steam side touching trained segment seals 76 and an outer, on the environment side, in particular air side, arranged labyrinth seal 78. In order to preload the labyrinth seal 78 axially, a wave spring 77 is arranged between the segment seal 76 aligned with the labyrinth seal 78 and the labyrinth seal 78.

The sealing segment packet formed by the segmental seal 76, the wave spring 77 and the labyrinth seal 78 is displaced in the direction of the piston rod 63 on the one hand by a guide bush 75 and on the other hand by a pressure plate

79 limited. The sealing segment packet is clamped by means of a plate spring 80 and a flange 81 axially against the guide bushing 75, wherein the plate spring 80 rests on the one hand on the pressure plate 79 and on the other hand on the flange 81. The labyrinth seal 78 is disposed within a thrust sleeve 83 with radial clearance to match the much greater clamping force of the disc spring

80 does not affect the axial preload of the labyrinth seal 78.

Between the labyrinth seal 78 and the inner, working chamber-side and the labyrinth seal 78 aligned segment seal 76 is a fluid channel 82 as a fluidic connection to the suction 67a as a low pressure region of the device 1, that is a condensing pressure p _K acted upon area formed. The fluid channel 82 extends in overflow slots formed on the pressure sleeve 83 and the wave spring 77 as far as the piston rod 63.

The cylinder relief valves 61 designed as overflow valves Expansion device 6 are connected to the work spaces, also referred to as cylinders. The cylinder safety valves 61 pressurized with the inlet pressure of the working medium into the expansion device 6, which corresponds to the evaporation pressure p _v during operation of the device 1, are configured such that when a pressure within the working space is exceeded of approximately 25% of the inlet pressure of the working medium into the expansion device 6 a connection to the outlet of the expansion device 6, in particular to the line L5 to the separator 9, is opened. The cylinder safety valves 61 also allow a quiet start-up or high-speed rotation of the expansion device 6, without an energetically relevant compression phase with looping during the inflow process.

Both on the piston rod 63 and on the outer portion of the spool 70 disc-shaped spray screens 69, 74 are arranged between the crankcase or the engine and the working space bounding cylinder to by centrifuging or dripping of the working fluid at the outer edges of the spray shield 69, 74th avoid any contact of any liquid working fluid and lubricant of the engine. This contact of working fluid and lubricant would be possible in principle after prolonged stoppage of the circuit 2 with pressure compensation.

The expansion device 6 is advantageously operated with an asymmetrical filling of about 20% at a pre-inlet less than 1% and a symmetrical outlet of about 40% in the pressure range above 15 bar. The dead space is about 6%. The compression pressure when opening the piston valve 70, also referred to as inlet slide, is about 20 bar. The lubrication of the crosshead 68 formed thrust crank engine of the expansion device 6 is as pressure circulation lubrication with lubricant sump and sight glass, separate lubricant pump and filter educated.

As can be seen again from FIG. 1, the separator 9 is connected to the condenser 11 designed as a plate heat exchanger, the heat being transferred from the working medium to the heating / cooling circuit. The vapor of the working medium flows from the top into the condenser 11, while the coolant flows out of the condenser 11 in countercurrent top.

In the lower region of the condenser 11, the outlet for the condensed working medium is arranged, through which the liquid working medium and air which has penetrated into the device 1, in particular into the expansion device 6, are sucked from the ejector 13. The ejector 1 3 thus sucks the entire condensate plus the air has penetrated into the device 1 and promotes into the reservoir 14. In this case, a small amount of vaporous working medium is removed and condensed to ambient pressure, so that the power of the ejector 13 according to the temperature increase, which results from the heat of condensation to be delivered, monitored in the subsequent reservoir 14 and, if appropriate, the pressure of the propulsion jet of the ejector 13 can be adjusted by regulating the backing pump 16, which is advantageously designed as a centrifugal pump. If the likewise monitored condensation pressure p _{K is} significantly above the saturation pressure of the working medium, it is necessary to close air to a high proportion of the inert gas.

The ejector 13 is formed next to the first connection for connection to the condenser 11 with the second connection for the extraction of the liquid working medium from the arrangement 8. The second connection is connected via the line L3 to the valve 19 with the collector 10.

The arrangement 8 for returning the lubricant with the separator 9 and the collector 10, the condenser 11, the ejector 13 and the reservoir 14 are aligned in a certain height allocation to each other. The ejector 13 is clearly below the inlet of the vapor into the condenser 11, but above the level of the float 40 of the collector 10 is arranged. The ejector 13 is also arranged in the height of the upper, filled with air region of the following reservoir 14, that is, the maximum filling level of the reservoir 14 is well below the inlet connected to the ejector 13.

The upper, filled with air region of the reservoir 14 has the steadily increasing degassing line 15 in communication with the environment outside the device 1, which is always open, so that prevails within the reservoir 14 ambient pressure pu. Air may possibly be sucked in through the degassing line 15 when the liquid level in the reservoir 14 drops, and in particular air that has penetrated into the device 1 as sealing gas is expelled from the device 1, or "saturated" air displaced as the liquid level increases induced changes in the evaporation pressure p _v. By means of the long-cooled vent line 1 5 of the dew point of the air is lowered, whereby condensed out working medium flows back into the reservoir 14. By means of the Auskondensierens of the vaporous working medium out of the to be derived air only a minimum amount of working medium in escapes Form of saturated at ambient temperature air from the device 1 into the environment.

If the ejector 13 sucks in a larger amount of steam and spends in the reservoir 14, the heat of condensation is transferred to coolant with a lower temperature, which is passed through the additionally integrated within the reservoir 14 coil. In this case, the coolant flows in particular through the tube coil integrated within the storage container 14 and subsequently or in parallel through the condenser 11. The in addition to the propulsion jet for the ejector 13 and a pre-pressure for the feed pump 17 generating backing pump 16 is connected in the lower part of the reservoir 14 and sucks liquid working medium. The Feed pump 17 is advantageously designed as a lubricated with the lubricant reciprocating pump with pressure-controlled valves, which prevents any backflow of hot working fluid from the evaporator 3 at standstill, which avoids the additional arrangement of a complicated non-return valve with damper in the long, pulsation-prone supply line to the evaporator 3 , The feed line is, according to the length, formed with a sufficient cross-section to prevent larger pulsations. As well as the fore pump 16 is controlled by the temperature T in the reservoir 14 and the temperature T and the pressure p at the outlet of the condenser 11, the speed of the feed pump 17, for example via frequency converter, corresponding to the temperature T of the exhaust gas at the inlet into the evaporator 3 and the temperature T and the pressure p of the steam at the outlet of the evaporator 3 regulated. The pressure p at the outlet of the vapor from the evaporator 3 is determined by means of the pressure sensor 43, which, according to FIG. 3 a, is arranged on the valve box 5. In this case, the entry state of the working medium in the expansion device 6 is selected such that the working medium after expansion flows only slightly superheated in the separator 9 or the condenser 11.

According to a particular embodiment, with the crankshaft of the feed pump 17 and the metering pump 18 is driven, since a high vapor pressure requires a large amount of lubricant in the cylinder of the expansion device 6 and a high flow rate of the metering pump 18. At the same time, the feed pump 17 can be lubricated with lubricant. The feed pump 17 and the metering pump 18 can also be driven by a common, speed-controlled motor.

The device 1 is supplemented with additional filling nozzles and drainage nozzles on the thrust crank engine of the expansion device 6, on the assembly 8 of separator 9 and collector 10 and on the reservoir 14.

With the device 1 is in the exhaust gases at high temperatures of a Internal combustion engine contained Exergie converted by a separate process into electrical energy. Due to the characteristic of the exhaust gases as a heat source, in particular as a capacitive heat flow, and the heat sink, in particular at a substantially constant temperature, the classical steam power process, also referred to as Clausius-Rankine process, with a significant proportion of overheating in the evaporator 3 and a small Enthitzen and supercooling used on the capacitor 11, which is suitable for the corresponding energy-temperature behavior. FIG. 5 shows the integration of the steam power process that can be carried out with the device 1 in a CHP system. In the circuit 2, water is circulated as a working medium. The device 1 is indicated by means of the evaporator 3, the expansion device 6 and the generator 7, the condenser 11 and the feed pump 17.

Alternatively, the device 1 may also be coupled to an internal combustion engine of a motor vehicle and integrated in the associated periphery.

The exhaust gas of the internal combustion engine 91 driving a generator 91 is passed through the evaporator 3, which generates superheated steam in cross-countercurrent or in countercurrent at superatmospheric pressure. Subsequently, the steam is expanded in the expansion device 6 to perform work, condensed to a lower pressure and conveyed by means of the feed pump 17 into the evaporator 3. The steam is condensed near the temperature level of the cooling water of the engine 90. Thus, the heat of condensation is transferred as waste heat to the outer cooling circuit 92 of the engine 90 and the heating circuit of the CHP system and used in particular in the mode in heating mode. In the mode in heating mode, which is indicated by the solid line arrow, the heating heat can be completely transferred to the temperature level of the cooling water. In the non-heating mode, which is indicated by the dashed-dotted arrow, no heat is required for heating, so that up to twice as much heat is transferred to the environment as compared to the cooling water heat. The Waste heat is transferred in the air heat exchanger 95 to the ambient air. The system is switched by means of the three-way valve 96 between the modes non-heating operation and heating operation.

The internal combustion engine 90 is also cooled by means of an internal cooling circuit 93, wherein the coolant transfers the heat dissipated by the internal combustion engine 90 in the heater-coolant heat exchanger 94 to the external cooling circuit 92.

With the integrated via the device 1 in the system steam power process, which combines the exergetic advantages of heat supply at high temperature level by means of an internal combustion engine with the advantages of heat dissipation at a low temperature level in the steam power process analogous to modern GU D power plants with turbomachinery can without the additional Use of fuel depending on the temperature of the exhaust gases of the internal combustion engine about 7.5% to 10% more electrical energy can be generated.

In the expected steam temperatures of about 400 ° C in particular water is used as the working medium in the circuit 2. The heat of the exhaust gas in the evaporator 3 thermodynamically can not be used up to the temperature level of the cooling water. For this reason, a heating exhaust heat exchanger 97 is downstream in the flow direction of the exhaust gas, in which the residual heat of the exhaust gas to the heating water in the heating circuit with a flow 98 and a return 99 is transmitted. The condenser 11 is therefore to be acted upon as the first component with the water of the return 99, which has the lowest temperature level of the cooling water or heating water.

If the device 1 has a fault as an additional steam power process, in addition to the pumps, in particular the feed pump 17, and thus the expansion device 6 and the separate generator 7 by means of an open bypass 100, the heat supply to the device 1, especially before the evaporator 3, are turned off. Similarly, with reduced use of the heating heat, the heater exhaust heat exchanger 97 can be bypassed by means of the bypass 101, so that the heat of the exhaust gas is released directly into the environment, without burdening the cooling water circuit, especially in the non-heating mode. The heat would otherwise have to be dissipated under the expense of additional fan power.

Since, when the utilization of the heating heat, the cycle is applied in the non-heating mode, so that the cooling medium flows through the air heat exchanger 95, and the circulation pump 102 is to be located at the position where the cooling medium has the lowest temperature, the circulation pump 102 arranged in the flow direction of the cooling medium directly in front of the condenser 11.

With the three-way valve 96 and the bypasses 100, 101 can be adjusted continuously modes between the heating operation and the non-heating operation.

Due to the setting at maximum power very large pressure conditions in the expansion device 6, the expansion device 6 is designed as a single-stage reciprocating engine in DC design. Despite the single-stage design, the expander 6 achieves isentropic grades of 70% over a wide load range at a mean piston speed of 4 m / s. When using water as the working medium of the evaporation pressure p _v at a condensation pressure p _K of about 0.7 bar between 15 bar and 60 bar, the superheat temperature of the vapor at the outlet of the evaporator 3 at particularly high temperatures of the exhaust gas up to 500 ° C is and the condensation temperature in the range of 80 ° C to 90 ° C. The high condensation temperature has a particularly advantageous effect on the process of transferring the heat from the working medium to the environment, especially in the non-heating mode. LIST OF REFERENCE NUMBERS

1 device for the use of exergy

2 cycle working medium

3 evaporators

4 flow direction exhaust gas

5 valve box

6 expansion device

7 generator

8 Lubricant return assembly

9 separator lubricant

10 collectors lubricant

11 capacitor

12 flow direction coolant condenser 11

13 ejector

14 storage tank

15 degassing line

16 forepump

17 feed pump

18 Dosing pump lubricant

19 valve

30 upper chamber

31 lower chamber

32 dividing wall

33 overflow connection

34 central tube Filler neck Lubricant Pressure equalization opening Intermediate base

bulkhead

swimmer

Connecting element sight glass

pressure sensor

Steam conversion

Pipe element Pressure relief valve Three-way valve

driving element

feather

spring chamber

valve seat

outlet space

rotary vane

Vane space

Openings inlet

Cylinder safety valve piston

piston rod piston nut

rod nut

a, 66b rod seal

a, 67b suction connection

c suction connection

Phillips

, 74 spray shield

spool

Slider body crank side

Slider body cover side

slide chamber

guide bush

segment seal

Well spring

labyrinth seal

printing plate

Belleville spring

flange

fluid channel

Pressure sleeve internal combustion engine

generator

Outer cooling circuit Internal combustion engine 90 Internal cooling circuit Internal combustion engine 90 Heating / cooling medium heat exchanger 95 air-heat exchanger

96 three-way valve

97 Heating exhaust heat exchanger

98 forerun

99 return

100 Bypass exhaust gas evaporator 3

101 Bypass exhaust heating heater exhaust heat exchanger 97

102 circulation pump

L1 overflow line - bypass valve box 5 separator lubricant 9

L2 line separator lubricant 9 condenser 11

L3 pipe collector lubricant 10 ejector 13

L4 pipe collector lubricant 10 expansion device 6

L5 line expansion device 6 separator lubricant 9

L6 line evaporator 3 valve box 5

L7 line valve box 5 expansion device 6

K condensation

n speed

p pressure

T temperature

U environment

V evaporation

Claims

claims

1 . Device (1) for the use of exergy, in particular a steam power plant designed for a steam power process, with a closed circuit (2) surrounded by air as atmosphere with an ambient pressure (pu), in which circulates a working medium, the circuit (2) in the flow direction of the working medium

an evaporator (3) for evaporating the working medium at an evaporation pressure (p _v ),

an expansion device (6) for releasing the working medium while performing mechanical work,

a condenser (11) for condensing the working medium at a condensation pressure (p _K ),

- A reservoir (14) and

a feed pump (17) for conveying the working medium to the evaporator (3)

wherein, downstream of the condenser (11), a component for conveying the working medium into the storage container (14) is formed, characterized in that dynamic seals between the working medium are operated within a region of the circuit (2) operated at the level of the condensation pressure (p _K ). and the environment are formed in two stages such that the device surrounding the air (1) rests against the dynamic seals as a sealing gas, the ambient pressure (pu) is greater than the pressure of the working medium in the circuit (2), in particular as pressure of the air the condensation pressure (p _K ).

2. Device (1) according to claim 1, characterized in that in the flow direction of the working medium between the condenser (11) and the reservoir (14) arranged component as an ejector (13) for sucking the working medium as well as the barrier gas the dynamic seals in the circuit (2) penetrated ambient air from the condenser (11) with a backing pump (16) for conveying a mass flow of the working medium as a propulsion jet of the ejector (13) is formed.

3. Device (1) according to claim 2, characterized in that the

Pre-pump (16) with an outlet of the reservoir (14) connected between the reservoir (14) and the feed pump (17) for conveying a mass flow of the working medium to the feed pump (17) is formed.

4. Device (1) according to one of claims 1 to 3, characterized in that the storage container (14) with a degassing line (15) is formed as a connection with the environment, wherein the degassing line (15) in an upper, filled with air Area of the reservoir (14) opens, steadily rising and cooled is formed such that vaporous working medium when flowing through the degassing (15) condensed at least for the most part and flows back down into the reservoir (14) and in the device (1) penetrated air can escape up into the environment.

5. Device (1) according to one of claims 1 to 4, characterized in that in the flow direction of the working medium after the expansion device (6) an arrangement (8) for the return of lubricant is arranged, wherein the arrangement (8) designed as a cyclone Separator (9) for separating working fluid and lubricant and a collector (10) for the lubricant, wherein the collector (10) is arranged in the direction of gravity below the separator (9).

6. Device (1) according to claim 5, characterized in that the

Collector (10) has a bottom, wherein in a central region of the collector (10) at the bottom of a valve (19) for sucking accumulated in the collector (10) working medium is formed.

7. Device (1) according to claim 5 or 6, characterized in that the collector (10) via a line (L3) for sucking working fluid from the collector (10) and conveying the working medium in the reservoir (14) with the ejector (13) is formed connected.

8. Device (1) according to one of claims 5 to 7, characterized in that the collector (10) via a line (L4) for sucking lubricant from the collector (10) and conveying the lubricant to the expansion device (6) with a Metering pump (18) is formed connected.

9. Device (1) according to one of claims 1 to 8, characterized in that the expansion device (6) is designed as a crosshead machine with a crosshead (68), a piston rod (63) and a piston (62), wherein the piston ( 62) crank side has an inner cone and a tapered piston nut (64) corresponding to the inner cone for adjusting and varying an axial piston play in the direction of the piston rod (63).

10. Device (1) according to claim 9, characterized in that the

Piston rod (63) through the housing of the expansion device (6), which defines a working space to the environment of the device (1), is guided, wherein between the piston rod (63) and the housing, a rod seal (66 a) is arranged, which a seal segment package having an outer non-contact labyrinth seal (78) and at least one inner contacting segment seal (76).

11. Device (1) according to claim 10, characterized in that between the outer non-contact labyrinth seal (78) and the inner contacting segment seal (76) a fluid channel (82) is formed as a connection to a region of low pressure of the circuit (2).

12. Device (1) according to claim 10 or 11, characterized in that the sealing segment packet with a plate spring (80) in the direction of the piston rod (63) is arranged axially braced to the working space.

13. Device (1) according to one of claims 10 to 12, characterized in that the labyrinth seal (78) with a corrugated spring (77) in the direction of the piston rod (63) is arranged axially biased to the external environment.

14. Device (1) according to one of claims 1 to 13, characterized in that the expansion device (6) has at least one working space, which is formed connected to a pressurized cylinder safety valve (61), wherein the cylinder safety valve (61) as a spill valve is a connection from the working space to an outlet of the expansion device (6) closable or apparently formed, as well as with an inlet pressure of the working medium in the expansion device (6), in particular the evaporation pressure (p _v ), acted upon and configured, when a certain pressure of the working medium is exceeded to open a connection to the outlet of the expansion device (6) within the working space.

15. Device (1) according to one of claims 1 to 14, characterized in that the expansion device (6) in a DC construction with

- A piston valve (70) with slider bodies (71, 72) with circular cylindrical cross-section and

- an inner inflow as well

- A piston rod (63) is formed with a circular cylindrical cross-section, wherein the slider body (71, 72) and the piston rod (63) have the same diameter.

16. Device (1) according to one of claims 1 to 15, characterized in that in the flow direction of the working medium between the evaporator (3) and the expansion device (6) designed as a valve box (5) combination of a shut-off valve, an overflow valve and a Pressure relief valve (50) is arranged, wherein the shut-off valve and the spill valve in a three-way valve (51) are formed combined.

17. Device (1) according to claim 16, characterized in that the

Valve box (5) has a rotary valve chamber (58) with a circular cylindrical cross-section, an outlet chamber (56) and a spring chamber (54), wherein the rotary valve chamber (58) with connections to the evaporator (3), to the expansion device (6) and to a separator ( 9) and the outlet space (56) have a connection to the condenser (11) or a separator (9).

18. Device (1) according to claim 17, characterized in that within the rotary valve chamber (58) a rotary valve (57) is arranged, which connected to a drive element (52) rotatable through an angle of 90 ° and in a between the Rotary slide chamber (58) and the outlet space (56) formed housing bushing is mounted radially movable.

19. Device (1) according to claim 17 or 18, characterized in that between the rotary valve chamber (58) and the outlet chamber (56) arranged housing passage on the side of the outlet space (56) is conically widened and a spherical segment-shaped valve seat (55) as a part of the drive element (52) bears in a sealingly movable manner on the conical extension, wherein the drive element (52) is mounted so as to move axially against a spring at a certain overpressure of the working medium within the rotary valve chamber (58), so that the valve seat (55 ) lifts off the conical extension and releases a gap between the rotary valve chamber (58) and the outlet chamber (56).

20. Device (1) according to any one of claims 17 to 19, characterized in that the three-way valve (51) formed with a Dampfübertritt (44) as a connection to the condenser (11) or the separator (9) and configured is, in an arrangement for closing the connection to the expansion device (6) to open the Dampfübertritt (44).

21. Use of a device (1) according to one of claims 1 to 20 in conjunction with an internal combustion engine

- a motor vehicle or

- of a ship or

- a CHP system

and exhaust gases as a heat source for evaporation of the working medium in the evaporator (3).