Disc turbine, method for operating a disc turbine, device for converting thermal energy into mechanical energy, method for converting thermal energy into mechanical energy, and method for converting thermal energy into electrical energy

Description

[0001] The invention relates to a disc turbine for converting the enthalpy of a gas flow rate into mechanical energy, as well as to a method for operating the disc turbine according to the invention. Furthermore, the invention relates to a device for converting thermal energy into mechanical energy, as well as to a method for converting thermal energy into mechanical energy and a method for converting thermal energy into electrical energy.

[0002] Gas turbines are limited in performance by the material of the rotor's force-absorbing elements. This can be compensated for by internal cooling of these elements, either by passing the cooling medium through them and allowing it to flow with the working fluid, or by a conservative cooling process in which the cooling medium remains intact. The former is state-of-the-art, using steam or air as the cooling media. The latter is also state-of-the-art, but with the limitation that the cooling medium, preferably water, is fed to the blades via the rotor shaft and evaporates in the blades.

[0003] US3899875 discloses a device that utilizes heat exchange in a Tesla turbine to increase the nozzle exit temperature, system power, and system efficiency. In addition to an external regenerator, the device includes a second regeneration system within the turbine blades themselves. The system facilitates the achievement of very high intake air temperatures at the inlet to the combustion chamber while also providing a means of cooling the turbine blades. By cooling the outer peripheral region of the blades, the maximum allowable temperature of the working gas at the nozzle is increased, as the blades are protected from the adverse effects of high temperatures, such as melting. With higher gas temperatures at the nozzles, higher power and turbine efficiency are achieved.If the regenerator parameters are correctly designed and adjusted, the cooling of the turbine blades can be achieved without significant cooling of the working gas exiting the nozzles.

[0004] US2009 / 0260361 A1 discloses an isothermal power generation system comprising an isothermal compressor for compressing a gas; a cooler supplying a cooling fluid to the isothermal compressor to cool the gas flowing through the isothermal compressor; a counterflow heat exchanger for heating the compressed gas; an isothermal expander for expanding the heated compressed gas to generate mechanical power; a heater supplying a heating fluid to the isothermal expander to heat the gas flowing through the isothermal expander; and means for passing the expanded gas back through the counterflow heat exchanger to add heat to the compressed gas flowing from the compressor through the counterflow heat exchanger, wherein the isothermal compressor draws in and compresses cooled and expanded gas flowing from the isothermal expander through the counterflow heat exchanger.

[0005] The present invention is based on the object of providing a disc rotor turbine and a method for operating a disc rotor turbine, a device for converting thermal energy into mechanical energy and a method for converting thermal energy into mechanical energy as well as a method for converting thermal energy into electrical energy, which enable the conversion of thermal energy into mechanical and / or electrical energy in an efficient manner.

[0006] The object is achieved according to the invention by a disc rotor turbine according to claim 1 and a method for operating the disc rotor turbine according to the invention according to claim 3. An advantageous embodiment of the disc rotor turbine according to the invention is shown in claim 2. An advantageous embodiment of the method according to the invention for operating the disc rotor turbine is shown in claim 4.

[0007] Furthermore, to achieve the object, a device for converting thermal energy into mechanical energy according to claim 5 and a method for converting thermal energy into mechanical energy according to claim 10 and, in addition, a method for converting thermal energy into electrical energy according to claim 11 are provided. Advantageous embodiments of the device according to the invention for converting thermal energy into mechanical energy are set out in claims 6 to 9.

[0008] A first aspect of the invention is a disc rotor turbine for converting the enthalpy of a gas volume flow into mechanical energy, comprising at least one disc arranged on a rotational axis, which can be set in rotation with a gas volume flow in a substantially tangential manner, such that mechanical energy can be extracted from a shaft coupled to the disc. A disc body forming the disc has at least one cavity in which a cooling medium, in particular a cooling liquid, is or can be accommodated for the purpose of cooling the disc body. Furthermore, the disc rotor turbine has at least one gas receiving chamber for receiving and discharging the gas volume flow flowing at least partially tangentially against the disc.

[0009] In other words, the disc rotor turbine according to the invention is a disc rotor turbine with at least one, preferably several discs arranged on a rotational axis, which can be set in rotation with a gas volume flow in the case of a substantially tangential flow, so that mechanical energy can be taken off at a shaft coupled to the disc, wherein the disc or the discs have at least one cavity in the disc body forming a respective disc, in which a cooling liquid is received or can be received for the purpose of cooling the disc body, and wherein the disc rotor turbine further has a gas receiving chamber for receiving and discharging an at least partial tangential gas volume flow onto the disc or discs.

[0010] Tangential flow is defined as the flow toward the disk(s) in a radially outer region of the disk in a direction essentially perpendicular to the rotation axis. Preferably, the flow toward the peripheral surface of the disk(s) is tangential.

[0011] The disc(s) are arranged on a rotational axis. The tangential flow causes the disc to rotate, in other words, to rotate around the rotational axis. Furthermore, the disc is coupled to a shaft, through which the mechanical energy of the rotation can be extracted. In one design, the disc(s) are mounted on the shaft in a rotationally fixed manner.

[0012] The disk has a substantially round shape in at least one plane, particularly a plane to which the disk's rotational axis is perpendicular. However, deviations from this round shape are also possible, for example, by having the disks have a blade shape. In other words, blade elements, such as those known from radial turbines, can also be used instead of disks.

[0013] The gas flowing toward the disk(s) is also referred to as the working fluid. This can be, for example, flue gas from a combustion plant or, alternatively, a working fluid heated by a heat exchanger. In the latter case, the working fluid is advantageously a noble gas, particularly xenon. Noble gases are useful because they are monatomic and incapable of radiating. Radiation from the gas body would lead to increased heat transfer, which poses the risk that the gas body between the turbine disks would cool too quickly and thus be unable to transfer any work to the disks, or only to a very limited extent.

[0014] A disk is formed by a disk body. A disk body of a disk, in particular of each disk, has at least one cavity. It is not excluded that a disk may have multiple cavities. In particular, the cavity extends from a radially inner region of the disk to a radially outer region of the disk.

[0015] The disk's cavity contains, or can contain, a cooling medium. Specifically, the cooling medium is a cooling liquid, meaning it exists in the liquid phase under ambient conditions. For example, the cooling medium is water. Organic or inorganic fluids and metals can be used as cooling media.

[0016] The disc turbine according to the invention has a gas receiving chamber. The gas, which flows tangentially against the disc(s), is introduced into the receiving chamber through an inlet device, received therein, and discharged through an outlet device. In other words, the gas receiving chamber is designed so that the gas can flow in and out of it, thus it consequently has an inlet and an outlet, wherein the inlet is preferably arranged in a region remote from the rotational axis of the discs and the outlet is arranged in a region close to the axis. The discs, preferably all discs, of the disc turbine are arranged within the gas receiving chamber.

[0017] In one embodiment of the disc rotor turbine according to the invention, the disc is designed to at least partially evaporate cooling medium received in its cavity when heat is supplied to the disc in the cavity from the gas volume flow flowing towards the disc.

[0018] In other words, the disc is designed to absorb heat from the gas volume flow that flows against or around the disc and to transfer it to the cooling medium in the cavity of the disc, so that the cooling medium inside the disc body at least partially evaporates.

[0019] In the case of multiple discs, at least one of the discs is configured to evaporate coolant contained in its cavity upon the supply of heat from the surrounding gas volume flow in the cavity. In principle, it is also possible for at least one of the discs to be configured to heat coolant contained in its cavity in the cavity substantially without evaporation upon the supply of heat from the surrounding gas volume flow.

[0020] In one embodiment, the vapor of the cooling medium is returned to the shaft, in particular the rotor shaft, and preferably expanded to dissipate force, condensed, and returned to the disks or blades. In this case, the cooling medium is led out of the cavity for condensation and returned to the cavity after condensation.

[0021] However, the condensed cooling medium can also be used in a different way. According to another embodiment, it does not leave the force-absorbing elements of the rotor, i.e., the disks or blades, at all, but is evaporated and condensed in situ. This process is similar to that in so-called "heat pipes." This is most easily achieved with rotating disks of a disk turbine similar to a Tesla turbine. The necessary condition is that the disks are hollow, in other words, have a cavity, and contain a cooling medium. As the disks rotate, the cooling medium is pushed radially outward to the outer edge of the disk, where it is evaporated by the hot gas surrounding the disk. The vapor of the cooling medium has a significantly lower density than the liquid phase of the cooling medium, so it can always be displaced by the liquid phase.This takes into account the fact that the heat flux densities at the radially outer edge of the disk are particularly high, but the liquid phase is able to absorb high heat flux densities without forming vapor cushions.

[0022] For reasons of continuity, the steam is directed into the central region of the disk, i.e. radially inward, where it condenses because the gas, which could be flue gas, for example, is colder near the axis of rotation or the shaft. The heat flows are advantageously adjusted or tuned using the boiling point, the amount of liquid, and the gas temperatures so that the absorbed heat flow is equal to the released heat flow. Due to the heat loss in the outer region of the disk, the gas is unable, or only able to do work on the disk to a very limited extent. This means that in this region heat is primarily transferred to the cooling medium inside the disk body. In the central, i.e. radially inner region of the disk, the heat is released back into the gas, although this is associated with equivalent work. This means that the gas transfers force to the disk almost isothermally.

[0023] The discs of the disc rotor turbine according to the invention are designed in such a way that they have an internal fluid circuit or cooling medium circuit in the cavity, so that evaporation occurs in the outer region and condensation occurs in the central, i.e. radially inner region as a result of external heat supply by and heat removal to a surrounding gas, preferably a hot flue gas, which is used as a working medium for generating mechanical energy.

[0024] The disk body typically consists, but not necessarily, of a metal. The strength of metals is fundamentally dependent on temperature and decreases progressively with increasing operating temperature, particularly with increasing gas flow temperature, of the disk turbine. This means that cooling the disks of the disk turbine according to the invention allows the turbine to operate at a higher operating temperature and increase energy consumption. Cooled disks therefore make it possible to use lightweight, low-strength materials for the disk body design without the risk of breakage. At the same time, the designs of disk turbines, in particular, become significantly more compact.

[0025] The effect of the disc rotor turbine according to the invention is that, due to the cooling of the disc, it is exposed to relatively low thermal stress, allowing a variety of materials to be used to form the respective disc body, including materials with low density and therefore low weight. In particular, discs made of materials with very low density can be rotated at very high speeds due to their resulting low mass moment of inertia, allowing the turbine to operate at high speeds and thus with high efficiency.

[0026] In a specific embodiment, the disc-rotor turbine according to the invention comprises a plurality of discs arranged on a rotational axis, wherein the disc bodies of adjacent discs are mechanically connected to one another by means of connecting elements. For this purpose, the disc bodies can, for example, comprise at least one recess or sleeve configured for the mechanical connection of at least one adjacent disc. In other words, the disc bodies are combined with one another by sleeves that enable external fastening.

[0027] Advantageously, spacer elements are arranged between two adjacent discs to ensure a defined distance. The spacer elements are mechanically arranged, preferably in the radially outer region of the discs. In this way, a disc package is realized.

[0028] A second aspect of the invention is a method for operating a disc rotor turbine according to the invention for converting the enthalpy of a gas volume flow into mechanical energy, wherein a gas volume flow is supplied to the disc in a manner flowing substantially tangentially to the disc, so that the disc is set in rotation due to friction.

[0029] Advantageously, several discs of a disc rotor turbine are set in rotation due to friction.

[0030] In one embodiment of the method according to the invention for operating the disc rotor turbine, heat of the gas volume flow is transferred to the cooling medium in the cavity of the disc body, so that the cooling medium at least partially evaporates.

[0031] In a special embodiment of the method according to the invention for operating the disc rotor turbine, heat of the gas volume flow is transferred to the cooling medium in the cavity of the disc body, so that the temperature of the cooling medium is increased, wherein the cooling medium remains substantially in the liquid phase.

[0032] A third aspect of the invention is a device for converting thermal energy into mechanical energy, which comprises a disc turbine according to the invention, wherein the disk of the disc turbine is arranged coaxially on a shaft. The shaft is mechanically connected to a compression unit, which has at least one compressor disk connected in a rotationally fixed manner to the shaft, such that upon rotation of the disc turbine, the compressor disk can be set in rotation. Furthermore, the compression unit comprises a compressor gas receiving chamber, which is fluidically connected to the gas receiving chamber of the disc turbine, such that gas compressed by the compression unit can be supplied to the disc turbine, in particular to the gas receiving chamber of the disc turbine.

[0033] In other words, the device for converting thermal energy into mechanical energy comprises a disc turbine according to the invention, wherein the disc or discs are arranged coaxially on a shaft, and wherein the shaft is mechanically connected to a compression unit which has one or more compressor discs which are rotationally fixedly connected to the shaft, so that upon rotation of the disc turbine, the compressor disc or compressor discs are set in rotation; and wherein the compression unit comprises a compressor gas receiving chamber which is fluidically connected to the gas receiving chamber of the disc turbine, so that gas compressed by the compression unit can be supplied to the disc turbine.

[0034] The disc-rotor turbine of the device according to the invention preferably comprises several discs arranged coaxially on a common shaft. The gas volume flow, which flows tangentially against the discs, causes them to rotate. The rotational movement is transmitted to the compressor disc(s) of the compressor unit through the rotationally fixed connection. In other words, the compressor disc is also rotated.

[0035] The compressor disks are arranged in a compressor gas receiving chamber. This compressor gas receiving chamber is fluidically connected to the gas receiving chamber of the disc turbine. In other words, gas exchange is possible between the compressor gas receiving chamber and the gas receiving chamber.

[0036] In a specific embodiment, both discs and compressor discs are arranged within a housing, but are separated at least in sections by a separating element.

[0037] The compressor unit compresses gas. In other words, the pressure of a gas is increased in the compressor unit, which typically also increases the temperature of the gas. Via the fluidic connection between the compressor gas intake chamber and the gas intake chamber, the compressed gas can be fed into the gas intake chamber and thus to the disks of the disc turbine for the purpose of performing work on the disks or the disk itself. The gas is expanded in the disc turbine.

[0038] Furthermore, expanded gas from the disc turbine can advantageously be fed to the compressor unit via an additional fluid connection, thus creating a closed gas circuit between the disc turbine and the compressor unit. A closed gas circuit for the working medium is advantageous, for example, when noble gases are used as the working medium.

[0039] The compressor unit of the device according to the invention for converting thermal energy into mechanical energy can also be referred to as a rotary compressor. The rotary compressor receives the working medium expanded in the disc turbine, in other words the expanded gas volume flow, preferably in a region close to the shaft. For this purpose, the rotary compressor is preferably arranged directly next to the expander, i.e., the disc turbine. In a specific embodiment, the compressed working medium leaves the compressor via tangentially oriented openings at the end of the two eccentric collectors and is fed to a combustion chamber for heating, where it is reheated, preferably by means of a heat exchange device.

[0040] In one embodiment of the device according to the invention for converting thermal energy into mechanical energy, the compressor disk has at least one cavity in a disk body forming the compressor disk, wherein the cavity of at least one disk of the disk rotor turbine is fluidically connected to the cavity of at least one compressor disk, so that cooling medium present at least partially in the gaseous phase can be fed from the cavity of the disk of the disk rotor turbine to the cavity of the compressor disk.

[0041] This means that the compressor disc or compressor discs also have a cavity in the respective disc body, wherein the cavity of the disc of the disc rotor turbine is fluidically connected to the cavity of the compressor disc, so that coolant in the gaseous phase can be fed from the cavity of the disc to the cavity of the compressor disc.

[0042] In other words, the cooling medium which is at least partially present in a gaseous phase and which has been at least partially evaporated by heat supply from the gas volume flow to the disk of the disk rotor turbine can be fed to a cavity which is formed by the disk body of the compressor disk by means of a fluidic connection between the cavity of the disk and the cavity of the compressor disk.

[0043] In principle, several disks of the disc turbine can be connected to several compressor disks of the compressor unit.

[0044] Preferably, the fluidic connection between the cavities of the disc and the compressor disc is formed in a region close to the shaft, so that the cooling medium, which is preferably present in the gaseous phase in the radially inner region of the cavity of the disc, can flow into the cavity of the compressor disc.

[0045] In a special embodiment, a second fluidic connection is formed between the cavities of the disk and the compressor disk in a radially outer region, so that the condensed cooling medium can flow from the cavity of the compressor disk into the cavity of the disk via this fluidic connection. In this way, a closed cooling medium circuit is formed between the compressor unit and the disk-type turbine or its disks.

[0046] In contrast to the expansion of the gas volume flow in the disc turbine according to the invention, in which the temperature of the working medium, i.e. the gas, constantly decreases, particularly in the isentropic case, the temperature constantly increases during isentropic compression in the compressor unit. During expansion in the disc turbine according to the invention, the heat is distributed within the disc in such a way that the heat dissipated in the radially outer region of the disc, i.e. in an area distant from the shaft, is returned to the radially inner region, i.e. close to the shaft, in essentially the same amount. The transition region between the radially outer and the radially inner region of the disc, also referred to as the remaining region of the disc, which is located in the area close to the shaft, enables essentially isentropic expansion.

[0047] During compression in the compressor unit, the above principle of heat distribution is reversed, namely in such a way that heat is dissipated in the radially inner area of ​​the disc, i.e. in the cavity of the compressor disc, and in the upper or radially outer area of ​​the compressor disc, heat is returned to the working medium in essentially the same amount.

[0048] In a further embodiment of the device according to the invention for converting thermal energy into mechanical energy, the compressor disk is rotationally fixedly connected to a rotatable cooling unit, wherein the cooling unit has at least one cooling disk arranged coaxially on a cooler shaft that is rotationally fixedly connected to the shaft of the disk turbine. Furthermore, the cooling disk has at least one cavity in the disk body forming the cooling disk, wherein the cavity of the cooling disk is fluidically connected to the cavity of the compressor disk, so that cooling medium heated in the compressor unit can be fed to the cooling unit, by means of which the cooling medium can be cooled in the cooling disk of the cooling unit and from there can be returned to the compression disk of the compressor unit.

[0049] In other words, the compressor disk or disks are connected in a rotationally fixed manner to a rotatable cooling unit, wherein the cooling unit also has a cooling disk or disks which are arranged coaxially on a cooler shaft which is connected in a rotationally fixed manner to the shaft of the disc turbine, wherein the cooling disk also has a cavity in its disk body for receiving cooling liquid and the cooling disk or disks are fluidically connected to the compressor disk or disks, so that cooling liquid heated in the compressor unit can be fed to the cooling unit, where the cooling liquid can be cooled in the disk(s) of the cooling unit and can be returned from this or these to the disk or disks of the compressor unit.

[0050] The cooling unit can also be referred to as a condenser, in particular as a rotary condenser, and is designed to communicate with the compressor unit, i.e. in particular to exchange the cooling medium with the compressor unit.

[0051] The cooling unit also includes discs, so-called cooling discs, arranged on a cooler shaft. The cooler shaft is connected to the shaft of the disc turbine in a rotationally fixed manner. In other words, the rotation of the disc turbine discs causes the cooling discs to rotate. It is not excluded that the cooler shaft and shaft form a structural unit.

[0052] The cooling disc also has a cavity. This cavity of the cooling disc is connected to the cavity of the compressor disc, so that a cooling medium that is introduced or can be introduced into the cavities can flow from one cavity to the other. Said medium is, in particular, a cooling medium that was heated in the compressor unit and flows from its cavity into the cavity of the cooling disc for cooling. In other words, heat is extracted from the cooling medium by means of the cooling disc. The cooled cooling medium is fed back to the compressor unit or the compressor disc. In other words, the second cooling medium is circulated between the compressor and cooling discs.

[0053] It is possible, but not mandatory, for the same cooling medium to be arranged in the cavity of a disk of the disc turbine as in the cavities of the compressor and / or cooling vanes. In a special embodiment, a first cooling medium is arranged in the cavities of the disks of the disc turbine, and a second cooling medium is arranged in the cavities of the compressor and / or cooling vanes.

[0054] The purpose of the cooling unit is to cool the coolant heated in the compressor unit, which is typically—but not necessarily partially—present in the gaseous phase in the cavity of the compressor disk. In other words, the cooling unit typically serves to condense the coolant, which is why the cooling unit can also be referred to as a condenser.

[0055] The cooling unit comprises a coolant receiving chamber for receiving and discharging a coolant, which at least partially flows around the cooling discs, so that the heat of the heated cooling medium can be transferred to the coolant for the purpose of cooling the cooling medium before it is returned to the compressor unit, in particular the cavity of the compressor disc. The coolant can also be referred to as the external coolant, while the cooling medium flowing between the cavities of the cooling and compressor discs can be referred to as the internal cooling medium.

[0056] The cooling unit or rotary condenser and the compressor unit or rotary compressor can be fully integrated into a housing, in particular the same housing as the disc turbine. However, the coolant receiving chamber and the compressor gas receiving chamber are advantageously separated from each other by a separating unit, so that essentially no exchange occurs between the gas in the compressor gas receiving chamber and the coolant in the coolant receiving chamber.

[0057] In a further embodiment of the device according to the invention for converting thermal energy into mechanical energy, a first fluidic connection between the cavity of the compressor disk and the cavity of the cooling disk is realized by means of at least one transverse web through which fluid can flow and which is arranged essentially axially parallel to the axis of rotation of the shaft between the compressor disk and the cooling disk.

[0058] In other words, the device comprises a first fluidic connection between the compressor disk(s) and the cooling disk(s), which is realized by means of at least one flow-through transverse web between the disks, which is arranged substantially axially parallel to the rotational axis of the shaft.

[0059] The flow-through crosspiece is advantageously formed by a pipe or several pipe sections, wherein the pipe cross-section of the pipe or the several pipe sections does not necessarily have to be round.

[0060] In order to create the fluidic connection, the flow-through crosspiece has openings which enable a connection between the interior of the crosspiece and the cavities of the cooling and compressor disc.

[0061] In a further embodiment of the device according to the invention for converting thermal energy into mechanical energy, at least one second fluidic connection between a cavity of at least one compressor disk and a cavity of at least one cooling disk is realized by means of a hollow connecting space in a shaft section, which extends from a shaft region covered by a compressor disk to a shaft region covered by a cooling disk. The covered shaft regions each have at least one opening axially for the purpose of implementing a flow of the cooling medium into and out of the hollow connecting space of the shaft, into and out of the cavity of the compressor disk and / or into and out of the cavity of the cooling disk.

[0062] In particular, this embodiment realizes a flow from the cavity of the compressor disc via the connecting space into the cavity of the cooling disc.

[0063] In other words, the device comprises a second fluidic connection between the compressor disk(s) and the cooling disk(s), which is realized by a cavity in a shaft section that extends from a shaft region covered by the compressor disk(s) to a shaft region covered by the cooling disk(s), wherein the shaft or the shaft section in question designed here each has at least one opening axially to allow flow from the disk in question into the cavity of the shaft or in the opposite direction.

[0064] Advantageously, but not necessarily, in this embodiment, the shaft on which the compressor disks are arranged and the cooling shaft form a structural unit.

[0065] The covered shaft sections each have at least one opening axially. In other words, the respective cavities of said discs are connected to the connecting space via the opening in the covered shaft sections.

[0066] Advantageously, the respective shaft section has a plurality of openings, preferably distributed at regular intervals around its circumference. In a specific embodiment, the openings in the covered shaft areas of the cooling disc and / or the compressor discs extend at an angle relative to a radial direction, so that the cooling medium flows tangentially into and / or out of the hollow connecting space. The specific design of the openings in the covered shaft area of ​​the cooling discs leads to a tangential acceleration of the cooling medium upon exiting the hollow connecting space.

[0067] By means of the first and the second fluidic connection, a closed cooling medium circuit of an internal cooling medium can be realized between the compressor unit and the cooling unit, in particular between the cavities of the respective discs, for cooling, in particular for condensation, of the internal cooling medium.

[0068] In the cooling unit or rotary condenser, the cooling medium inside the cooling discs has a higher density than in the discs of the evaporator or compressor unit. Similar to a natural circulation boiler, the condenser acts as a downpipe system and the compressor as a riser system, with the only difference being that the fluid or cooling medium moves radially due to centrifugal force. In the condenser, the fluid moves outwards away from the shaft axis, is guided through short tubes or crossbars into the evaporator or compressor discs of the compressor unit, where it moves towards the shaft axis, i.e. radially inwards. There are bores or openings designed as bores in the shaft that clear the way into the hollow connecting space of the shaft, allowing the fluid to be returned to the condenser area or cooling unit.The shaft is sealed axially from the environment by baffles, thus forming the hollow connecting space.

[0069] An external coolant, particularly ambient air, water from the environment, or another external heat sink, flows around the outer disc regions of the cooling discs of the cooling unit. These external flows are hermetically separated by a separating device or a separating disc that is guided into the outer edge of the turbine casing. In other words, in a compact design in which the disc turbine, compressor unit, and / or cooling unit are integrated into a common housing, the external coolant is essentially fluidically separated from the gas surrounding the discs of the compressor unit and / or disc turbine.

[0070] The external coolant preferably enters in a region close to the shaft, where the internal cooling medium still has a high vapor content. This makes the condensation effect stronger than in the reverse process. The compressor unit typically operates at a roughly constant temperature, but not necessarily at a constant temperature, as does the internal cooling medium, which is in a vaporizing state. Due to the increasing density of the working fluid being compressed in the compressor unit, there is an increased heat flux, or heat transfer, to the internal cooling medium. This is compensated for by increased vapor formation, whereby the temperature difference remains essentially constant throughout the entire compression range of the device.

[0071] In a specific embodiment, the rotary condenser or cooling unit preferably draws in ambient air as a coolant, which is brought to rotational speed by helically shaped and fixed blades placed around or arranged on the shaft, in particular the cooling shaft. This creates a suction effect, and acceleration losses at the disks are avoided. The air exits the rotary condenser through preferably tangentially oriented openings at the outer edge of the coolant receiving space or the turbine housing, if the elements of the device according to the invention form a structural unit. In principle, a cooling liquid could also be drawn in as a coolant as an alternative to ambient air.

[0072] The effect of the device according to the invention for converting thermal energy into mechanical energy is, in particular, that due to the high efficiency of the integrated disc rotor turbine, the entire device can also be operated with a high efficiency, so that a relatively low thermal or chemical energy input is necessary to provide the desired amount of mechanical or electrical energy.

[0073] In a special embodiment of the device according to the invention, a propeller element is arranged stationary in the hollow connecting space of the shaft section, so that a substantially axial flow movement of the cooling medium in the shaft can be realized when the shaft rotates relative to the propeller.

[0074] A fourth aspect of the invention is a method for converting thermal energy into mechanical energy, in which the method according to the invention for operating a disk-type turbine is carried out in a device according to the invention for converting thermal energy into mechanical energy. In this case, heated cooling medium is supplied to at least one cooling disk, in particular from the cavity of a compressor disk, and cooled there. After the cooling medium has cooled, it is fed back to a compressor disk.

[0075] In other words, in the method according to the invention, coolant heated in the compressor disk or the compressor disks is supplied to the cooling disk or the cooling disks and cooled there, and after cooling is supplied again to the compressor disk or the compressor disks.

[0076] A fifth aspect of the invention is a method for converting thermal energy into electrical energy, in which the method according to the invention for converting thermal energy into mechanical energy is carried out and kinetic energy of the rotating shaft is converted into electrical energy by means of a generator.

[0077] The invention is explained below with reference to the embodiments shown in the accompanying drawings.

[0078] It shows Fig. 1 : a section of a disc rotor turbine according to the invention; Fig. 2 : in one embodiment of the device according to the invention for converting thermal energy into mechanical energy, the interaction of a compressor disk and a cooling disk in an idealized manner; Fig. 3: a section of an embodiment of the device according to the invention for converting thermal energy into mechanical energy with three compressor and cooling disks each; Fig. 4 : a section perpendicular to the axis of rotation through the shaft of a device according to the invention; Fig. 5 : an embodiment of the device according to the invention for converting thermal energy into mechanical energy, in which the disc rotor turbine, compressor unit and cooling unit are arranged in one housing; Fig. 6 : a section through the disc rotor turbine according to the invention perpendicular to the axis of rotation; Fig. 7 : an embodiment of the method according to the invention for converting thermal energy into electrical energy as a plant flow diagram; Fig. 8 : a pV diagram for expansion and compression of the first working medium in the high pressure or high temperature range according to Figure 7 ; Fig. 9 : e that to Figure 8corresponding Ts diagram for expansion and compression of the second working medium in the high pressure or high temperature range according to Figure 7 ; Fig. 10 : a pV diagram for expansion and compression of the second working medium in the low pressure and low temperature range according to Figure 7 as well as Fig. 11 : the Figure 10 corresponding Ts diagram for expansion and compression of the second working medium in the low pressure or low temperature range according to Figure 7 .

[0079] Figure 1shows a section of a disc turbine 10 according to the invention. Shown are three disks 11 which are arranged rotationally fixed on a shaft 51 and rotate about the axis of rotation 51. The middle of the three essentially round disks 11 is shown in section. It can be seen that the disk body 13 forming the disk 11 has a cavity 14 in which a cooling medium 16, in particular a cooling liquid, is accommodated. In the space 15 between the disks there is hot gas 17 which, upon entering the disc turbine 10, flows tangentially against the disks 11, preferably at their outer surface, and thus sets the disks 11 in rotation about the axis of rotation 50. The gas 17 which flows against or around the disks 11 is also referred to as the working medium. This can be a flue gas from a combustion process or alternatively a noble gas such as xenon.The gas 17 is typically over 100°C hot and has a higher pressure than the ambient conditions. During operation of the disc turbine 10, the gas 17 transfers energy to the discs 11. The discs 11 are heated by the gas 17 during operation. The cooling medium 16 in the cavity 14 serves to cool the discs 11 during operation. The cooling medium 16 is, for example, water, although other organic or inorganic substances or mixtures of substances are also possible.

[0080] Figure 1 illustrates the cooling process of the disks 11 in an idealized manner. Primarily in the radially outer region, in which the gas 17 preferably enters the disk turbine 10 according to the invention, heat is transferred from the gas 17 located in the disk space 15 to the disk body 13 and subsequently to the cooling medium 16 located in the cavity 14. This heat flow is in Figure 1indicated by arrows pointing towards the cavity 14 of the discs 11. In the radially outer region of the cavity 14, the cooling medium 16 is present primarily as a liquid cooling medium 162. The heat input causes the liquid cooling medium 162 to evaporate. The cooling medium 161, now in gaseous form or as vapor, flows radially inward inside the cavity 17. This flow movement is in Figure 1 indicated by an arrow pointing towards the shaft 51. In the vicinity of the shaft, condensation of the cooling medium 16 occurs, so that a film of liquid cooling medium 162 is formed on the walls of the cavity 14. The heat released during the condensation is in turn transferred from the disc body 13 to the gas 17 located in the space between the discs 15. This heat flow is in Figure 1indicated by arrows pointing toward the disc space 15. Due to the density difference between the phases and the centrifugal forces generated by the rotation, the film of liquid cooling medium 162 moves radially outward, where the liquid cooling medium 162 is evaporated again. In this way, internal cooling of the discs 11 of the disc-rotor turbine 10 is realized.

[0081] In other words, the disks 11 of the disk rotor turbine 10 according to the invention are designed in such a way that they have an internal fluid circuit or cooling medium circuit in the cavity 14, so that evaporation of the cooling medium 16 occurs in the outer region and condensation of the cooling medium 16 occurs in the central, i.e. radially inner region as a result of external heat supply and heat removal to a surrounding gas 17, for example a hot flue gas, which is used as a working medium for generating mechanical energy.

[0082] The disk body 13 typically consists—but not necessarily essentially—of a metal. The strength of metals is fundamentally dependent on temperature and decreases with the temperature of the gas 17. The disk turbine 10 according to the invention, thanks to the internal cooling by means of the cooling medium 16, allows the use of lightweight, low-strength materials for the design of the disk body 13.

[0083] Figure 2shows, in an idealized manner, the interaction of a compressor disk 21 and a cooling disk 31. The disk bodies 22, 32 of both disks 21, 31 each form a cavity 24, 34. The cavities 24, 34 of the compressor disk 21 and the cooling disk 31 are fluidically connected to one another by means of transverse webs 42. This means that the cooling medium 16 present in the two cavities 24, 34 can flow between the cavities 24, 34. In other words, the transverse webs 42, aligned parallel to the rotation axis 50, form a first fluidic connection.

[0084] Both in Figure 2The disks 21, 31 shown are arranged in a rotationally fixed manner on a shaft 51, which rotates about a rotation axis 50. Via the shaft section boundaries 45, the shaft 51 forms a hollow connecting space 43 within it. The hollow connecting space 43 is fluidly connected via the openings 44 to both the cooling disk 31 and the compressor disk 21. In this way, a second fluidic connection is formed.

[0085] The heat flow in the space surrounding the discs 21, 31 is in Figure 4 indicated by arrows. In the area of ​​the compressor disk 21, the gas surrounding the disk is warmer than in the area of ​​the cooling disk 31. Due to the heat transfer from the surrounding gas to the compressor disk 21, the cooling medium 16 located in the cavity 24 of the compressor disk 21 evaporates. In a similar way to the Figure 1illustrated process, the portion of the cooling medium 16 present in the gaseous phase flows radially inward and through the opening 44, which connects the cavity 24 of the compressor disk 21 with the hollow connecting space 43, into the hollow connecting space 43 of the shaft 51. In the hollow connecting space 43, the cooling medium 16, which here is primarily present as a gaseous cooling medium 161, flows in a second cooling medium flow 164 towards the cooling disk 31 and through the

[0086] Opening 44, which connects the cavity 34 of the cooling disk 31 with the hollow connecting space 43, into the cavity 34 of the cooling disk 31. In particular, this leads to cooling and, as a result, to condensation of at least a portion of the gaseous cooling medium 161. The now essentially liquid cooling medium 162 is moved radially outward due to rotation and flows through the transverse webs 42 in a first cooling medium flow 163 into the cavity 24 of the compressor disk 21, where it is reheated and evaporated. In this way, a closed cooling medium circuit between a compressor disk 21 and a cooling disk 22 is, in principle, feasible. Figure 2 The process shown is to be understood as an idealized process.

[0087] Figure 3shows a section of an embodiment of the device according to the invention for converting thermal energy into mechanical energy. Shown here is the interaction of a compressor unit 20 with a cooling unit 30. Each of the two units 20, 30 has, as an example, three disks 21, 31, which are arranged rotationally fixed on a shaft 51. Their Figure 3 Cavities not shown are interconnected to form a first fluidic connection, in this example by means of a crosspiece 42. A second fluidic connection is realized via the hollow connecting space 43 and the openings 44.

[0088] In a similar way to the Figure 2 In the illustrated process, the cooling medium 16, which is present in the cavities 24, 34 of the discs 21, 31, flows in a circuit. This circuit is in Figure 3 shown by arrows.

[0089] The compressor unit 20 and the cooling unit 30 share a common housing 52. A separating element 41 separates each of the two units 20, 30 into a separate receiving chamber 22, 32. This means that the cooling disks 31 are arranged in a coolant receiving chamber 32, and the compressor disks 21 are arranged in a compressor gas receiving chamber 22. The two receiving chambers 22, 32 are separated from each other by the separating element 41 in such a way that there is essentially no exchange of the media located in the receiving chambers 22, 32.

[0090] In the illustrated embodiment, a heated gas 17 or working medium enters the compressor unit 20 through a gas volume flow inlet, which is preferably arranged in a radially inner region of the compressor unit 20. The gas 17 releases heat to the compressor disks 21 in the compressor unit 20. In the process, the cooling medium 16 present inside the compressor disks 21 is heated and preferably evaporated. The gas 17, now colder than the gas inlet temperature, leaves the compressor gas receiving chamber 22 through a gas volume flow outlet 222, which is preferably arranged in the radially outer region of the compressor unit 20.

[0091] The heated and at least partially evaporated cooling medium 16 flows radially inward inside the compressor disks 21 and through the openings 44 of a shaft region 25 covered by a respective compressor disk 21 into the hollow connecting space 43 inside the shaft 51, which is delimited by the shaft section boundaries 45. From the hollow connecting space 43, the cooling medium 16 flows through openings 44 of a shaft region 35 covered by a respective cooling disk 31 into the hollow space 34 of the respective cooling disk 31 of the cooling unit 30. The cooling disks 30 are arranged in a coolant receiving space 32. A coolant 37 enters the coolant receiving space 32 via a coolant inlet 321, which is preferably arranged close to the shaft. While the cooling medium 16 inside the discs 21, 31 is preferably a cooling liquid which can be evaporated, ambient air can also be used as the coolant 37.However, it cannot be ruled out that the coolant 37 is also a cooling liquid. In particular, it cannot be ruled out that the coolant 37 has the same material composition as the cooling medium 16.

[0092] Heat is transferred from the cooling medium 16 to the coolant 37 via the disc bodies of the cooling discs 31. In particular, so much heat is transferred that the cooling medium 16 condenses and changes from the gaseous to the liquid phase. Due to the density differences between the phases and the centrifugal forces acting due to the rotation, the liquid cooling medium 16 is moved radially outward inside.

[0093] The rotation of the disks 21, 31 is due to the fact that the shaft 51, on which the disks 21, 31 are arranged, is rotationally fixedly connected to a turbine, in particular a disk turbine 10 according to the invention. Figure 3 this connection is not shown.

[0094] Figure 4 shows a section perpendicular to the axis of rotation 51 through the shaft 51 on which the cooling disks (not shown here) are arranged in a rotationally fixed manner. The section shown lies in a plane in which the openings 44 are arranged. It can be seen that the shaft 51 has a hollow connecting space 43 in its interior. It can also be seen that the openings 44 are arranged at regular intervals on the circumference of the shaft 51. In the present embodiment, the openings 44 are cylindrical bores. The axis of a respective bore runs at an incline with respect to a radial direction. An angle formed between the axis of the bore and the radius of the shaft 51 is acute in the direction of rotation 501.

[0095] In the present example, the openings 44 are to be designed such that no excessive shock loss occurs in the downstream flow behind the openings 44. The inlet into the cavity of the cooling disc (not shown here) is preferably designed such that a certain advance is created at the inlet in order to reduce the energy absorption of the cooling medium (not shown here).

[0096] Figure 5 shows an embodiment of the device according to the invention for converting thermal energy into mechanical energy. In the illustrated embodiment, the disc turbine 10, the compressor unit 20, and the cooling unit 30 are arranged in a housing 52. Seals 53 are arranged between the housing 52 and the rotating shaft 51.

[0097] The disc turbine 10 comprises in the illustrated embodiment two discs 11. The discs 11 preferably have a disc cooling system as shown in Figure 1 The gas 17 enters the gas receiving chamber 12 of the disc turbine 10 via the gas volume flow inlet 221 and flows preferably tangentially against the discs 11. The discs 11 are thereby set in rotation about the rotation axis 50. Both the discs 11 and the compressor discs 21 and the cooling discs 31 are arranged in a rotationally fixed manner on a common shaft 51. Consequently, a rotation of the discs 11 leads to a rotation of the compressor discs 21 and the cooling discs 31. In the disc turbine 10, the gas 17 is at least partially expanded and cooled.

[0098] The gas 17 flows into the compressor gas receiving chamber 22 of the compressor unit 20 via a gas volume flow transition 223 arranged near the shaft. To facilitate this gas flow, the disks 11 have disk openings 131 in a region near the shaft. The separating element 41 between the gas receiving chamber 12 and the compressor gas receiving chamber 22 also has at least one opening near the shaft. In the illustrated embodiment, a seal 53 is arranged in the radially outer region on the gas receiving chamber side.

[0099] In the compressor unit 20, the expanded working medium or gas 17 transfers heat to the compressor disks 21. The compressor disks 21 have, as shown in Figure 2shown, via a cavity (not shown here), in which a cooling medium 16 is accommodated. The cooling medium 16 can be the same cooling medium 16 that is accommodated in the cavities of the disks 11 of the disk turbine 10. The cooling medium 16 inside the compressor disks is evaporated by means of the heat from the gas volume flow 17. The latter is compressed in the compressor unit 20 and flows out of the compressor unit 20 via the gas volume flow outlet 222 and can be fed to a burner (not shown here) or a heat exchanger device for reheating.

[0100] In addition to the compressor unit 20, a cooling unit 30 is arranged in the same housing 52. The coolant receiving chamber 32 of the cooling unit 30 is separated from the compressor gas receiving chamber 22 of the compressor unit 20 by a separating element 41. In addition, a seal 53 is also provided radially outwardly on the compressor gas receiving chamber side. Analogous to the illustration in Figure 3 Cavities of the compressor disks 21 are connected by means of crosspieces 42 in a first fluidic connection with cavities of the cooling disks 31 (not shown here), wherein in this embodiment, three parallel arranged crosspiece connections are provided. Also analogous to Figure 3, a second fluidic connection is formed between the cavities of the compressor disks 21 and the cooling disks 31 via the openings 44 and the hollow connecting space 43 formed by the shaft section boundary 45. The cooling medium 16 can thus be circulated between the compressor unit 20 and the cooling unit 30 or their disks 21, 31.

[0101] Also in Figure 5 The coolant inlet 321 near the shaft is shown. In the cooling unit 30, the heat of the cooling medium 16 heated in the compressor unit 20 is transferred to the coolant 37. In particular, the cooling medium 16 is condensed in the cooling unit 30.

[0102] Figure 6 shows a section through the disc rotor turbine 10 according to the invention perpendicular to the axis of rotation 50, as in the embodiment according to Figure 5The tangential gas flow inlet 221 into the gas receiving chamber 12, which is radially delimited by the housing 52, can be seen. The gas flow accelerates the disk 11 due to friction, thus generating a rotation 501. Also visible are the disk openings 131 arranged near the shaft 51, through which the gas 17 flows toward the compressor unit (not shown here). Figure 6 it is indicated that the gas 17, when passing through the disk opening 131, experiences an acceleration with at least one directional component radially outwardly opposite to the direction of the rotation 501.

[0103] In Figure 7 An embodiment of the process according to the invention for converting thermal energy into electrical energy is shown as a plant flow diagram.

[0104] The plant flow diagram illustrates a sliding operation. This means that compression occurs at a higher temperature level to allow for the extraction of heat for external use. The numerical values ​​for temperatures and pressures given below are examples.

[0105] The process illustrated comprises a low-pressure region 70 and a high-pressure region 80. The process can also be referred to as a gas turbine process. A first working medium 100 is circulated in the high-pressure region 80, as well as a second working medium 200 in the low-pressure region 70. Also illustrated is the supply of combustion air 300 to a combustion chamber 67, which is first preheated by a fourth heat exchanger 65 and subsequently by a third heat exchanger 63, and is supplied to the combustion chamber 67 as preheated combustion air 303. Furthermore, the flow of a heat transfer medium 400 is illustrated. The flue gas 600, after being cooled by a second heat exchanger 62, is discharged as cooled flue gas 601 via a chimney 66.

[0106] In a combustion chamber 67, a fuel 500 is burned to generate heat. The combustion chamber 67 can, in principle, be operated with any fuel. It can therefore be equipped with a solid fuel furnace or with a burner for fluid fuels. The walls of the combustion chamber 67 are preferably cooled with the media available for the process, in particular the first working medium 100, or constructed of refractory material.

[0107] For combustion, a fuel 500 and preheated combustion air 303 are fed to the fictitiously adiabatic combustion chamber 67. The flue gas 600 formed there leaves the combustion chamber 67 at approximately 2000°C or is present therein at the corresponding temperature. In a first heat exchanger 61 (not shown in detail here), which is connected downstream of the combustion chamber or directly adjacent to it and which can also be partially structurally connected to the combustion chamber walls to cool them, the flue gas 600 is first cooled to a temperature of approximately 500°C, then fed to a second heat exchanger 62, which can also be referred to as an economizer, for heating the second working medium 200 for the low-pressure turbine or the low-pressure expander 72, and is fed into the chimney 66 as the cooled flue gas 601 at approximately 100°C.

[0108] The heat released by the flue gas 600 is used to heat the first working medium 100, which enters the first heat exchanger 61, the waste heat exchanger, as a compressed first working medium 104 at a temperature of approximately 400°C and exits as a heated working medium 101 at a temperature of approximately 1500°C. The first working medium 100 is preferably xenon or an alternative noble gas. The heated and compressed first working medium 101, 104 are under a pressure of approximately 15 bar, not taking into account minimal pressure differences that occur as a result of transport. In a high-pressure expander 82, the first working medium 101 is reduced to a pressure of 1 bar, while simultaneously being cooled to a temperature of approximately 400°C before leaving the high-pressure expander 82 as an expanded first working medium 102.The expansion process preferably takes place partially or completely isothermally at a working temperature higher than 400°C, but not at temperatures higher than the inlet temperature of the working medium 101. In this embodiment of the method, the high-pressure expander 82 comprises or is formed by at least one disc turbine according to the invention (not shown here). The first working medium 100 therefore corresponds to the gas volume flow or the gas in the . Figures 1 to 6 .

[0109] The level of the working temperature in the high-pressure expansion device 82 depends on the selected cooling medium and the material of the expansion disks or disks of the disc turbine.

[0110] The output shaft energy is transferred to a generator 68 via shaft 51, where it is converted into electrical energy. Within the expansion stage, the heated first working fluid 101 is first lowered to a working temperature, with the dissipated heat being returned to the heated first working fluid 101 during the actual expansion. In this way, the temperature remains virtually constant during expansion. The final phase of expansion occurs almost isentropic to minimize exergetic losses.

[0111] The expanded first working medium 102 is further cooled in a third heat exchanger 63, which acts as an air preheater for the combustion process, at approximately the same pressure to a cooled first working medium 103 with a temperature level of 80 to 200°C, after which it enters a high-pressure compressor 81. In the high-pressure compressor 81, which is preferably designed as a compressor unit, an isothermal pressure increase to 15 bar takes place. In the final phase of this process step, the pressure increase can also occur isentropically; accordingly, the temperature would rise by a certain amount. The extent to which this is permitted depends on the material from which the compressor disks 21 in the high-pressure compressor 81 are made and the exergetic loss that is acceptable with regard to heat transfer. The compressor disks 21 are cooled by a cooling medium 16 circulating internally in the compressor disks 21 or in the cavity 24 of the compressor disks 21.This cooling medium 16 transfers its heat to a heat transfer medium 400 coming from the environment. The cool heat transfer medium 401 is supplied from a heat sink 64 to the high-pressure compressor 81, heated there, and then returned to the heat sink 64 as a warm heat transfer medium 402 with an elevated temperature level. The heat transfer medium 400 is typically ambient air or water. The compressed first working medium 104 is supplied to the first heat exchanger 61, thus closing the circuit of this first working medium 100.

[0112] In the low-pressure region 70, the flue gas 600 leaves the combustion chamber 67 at a temperature of 500°C. In the illustrated embodiment, this temperature level is utilized in a second gas turbine process operating at low pressure. Analogous to the high-pressure turbine, the low-pressure turbine consists of a low-pressure expander 72 operating at approximately 400°C and 5 bar, and a low-pressure compressor 71, which is isothermal in design and at whose outlet a compressed second working medium 204 exits at a temperature of approximately 50°C and a pressure of approximately 5 bar. In the illustrated embodiment, the low-pressure turbine and the high-pressure turbine are arranged on the same shaft 51.

[0113] This low-pressure expander 72 is designed with cooled discs in a similar manner to the high-pressure expander 82 of the high-pressure section 80. The waste heat from the low-pressure expander 72 is used to heat the ambient air 301 at approximately 10°C to an intermediately heated combustion air 302 at approximately 80°C in a fourth heat exchanger 65, which can also be referred to as a low-temperature preheater. The ambient air 301 arrives at approximately 10°C, so that the expanded second working medium 202, which is preferably also xenon or another noble gas, can be cooled to a cooled second working medium 203 at approximately 20°C. The required cooling flow for the low-pressure compressor 71 comes from the environment and is thermally worthless. The low-temperature turbine could also be operated in gliding mode to extract process heat.

[0114] As an alternative to the low-temperature gas turbine, a Rankine cycle could also be designed. This would have the advantage of generating steam that can be used for specific process purposes.

[0115] Figure 8 a pV diagram for expansion and compression of the first working medium in the high pressure or high temperature range according to Figure 7 . Figure 9 shows that Figure 8 corresponding Ts diagram for expansion and compression of the second working medium in the high pressure or high temperature range according to Figure 7 .

[0116] The pV diagram shows the integrals for the technical work to be supplied and the work gained. The Ts diagram shows the corresponding heat integrals for heat input and heat removal. After partial isothermal compression, which is shown in Figures 8 and 9corresponds to the change of state from 3 to 4, the working medium is further compressed isentropically to the final temperature or pressure, which is Figures 8 and 9 corresponds to the change of state from 4 to 5. Alternatively, the compression could be completely isothermal, which is Figures 8 and 9 corresponds to the change of state from 3 to 5, but this would require more powerful cooling. The resulting increased cooling energy would be absorbed preferentially by the combustion air in the combustion chamber, which already absorbs the energy of the change of state from 3 to 4. This would result in certain exergetic losses due to transmission losses, but this approach can have structural and thus economic advantages.

[0117] After isobaric cooling, the first working fluid is compressed isothermally, whereby the compression could also be only partially isothermal if isentropic compression were allowed to occur in the final phase of this step. This degree of freedom is required to economically optimize the design, as in the case of high-temperature compression. This case represents Figures 8 and 9 represents the lower limit line for compression. The limit lines above represent sliding operation as an example. The inlet temperature into the expander could also slide, but for exergetic reasons it is sensible to always operate the expander at maximum temperature.

[0118] In contrast to expansion, where the temperature of the working medium decreases continuously in isentropic conditions, the temperature increases continuously in isentropic compression. This behavior is represented by the dashed lines in the Figure 8This also tends to apply to the partially isothermal process steps, whereby during expansion in the range from state 0 to state 3 the temperature tends to decrease and during compression the temperature increases from state 4 to state 5. This means that during expansion heat must be added to the working area and during compression heat must be removed accordingly, so that isothermal or as in Figures 8 and 9 shown partially isothermal changes of state can occur.

[0119] Figure 10 shows a pV diagram for expansion and compression of the second working medium in the low pressure and low temperature range according to Figure 7 .

[0120] Figure 11 shows that Figure 10 corresponding Ts diagram for expansion and compression of the second working medium in the low pressure or low temperature range according to Figure 7 .

[0121] The functioning of the disc turbine according to the invention and the device according to the invention for converting thermal energy into mechanical energy, as well as the respective methods for operating the disc turbine according to the invention and the device according to the invention can also be represented as follows.

[0122] In the following, unless otherwise indicated, the terms condenser and rotary condenser refer to a cooling unit.

[0123] In embodiments of the invention, the following applies: The term cooling liquid is to be understood as a cooling medium, wherein the internal fluid is to be understood as the cooling medium in cavities of disks, compressor disks and / or cooling disks. An external coolant or cooling medium is to be understood as a coolant which flows against or around the cooling disks. The terms flue gas and working medium are to be understood as gas or gas volume flow. In the following, an expander is to be understood as an expander which is preferably designed as a disk turbine according to the invention, also referred to below as a disk turbine. An element which is referred to below as a compressor corresponds to a compressor unit. Disc rotor turbine:

[0124] Gas turbines are limited in performance by the material of the rotor's force-absorbing elements. This can be compensated for by internal cooling of these elements, either by passing the cooling medium through them and allowing it to flow with the working fluid, or by a conservative cooling process that retains the cooling medium.

[0125] The former is state-of-the-art, using steam or air as the cooling medium. The latter is also state-of-the-art, but with the limitation that the cooling medium, preferably water, is fed to the blades via the rotor shaft and evaporates in the blades.

[0126] The steam is returned to the rotor shaft and preferably expanded, condensed and returned to the blades in a force-dissipating manner.

[0127] The condensed cooling medium can also be used in other ways, however, by not leaving the force-absorbing elements of the rotor at all, but evaporating and condensing in situ, similar to what happens with so-called "heat pipes." This is most easily achieved with rotating disks of a disk turbine (Tesla), as shown in Figure 1 , where the necessary condition is that the discs are hollow and contain a cooling medium. As the discs rotate, the cooling medium is pushed to the outer edge of the disc, where it evaporates due to the hot gas surrounding the disc. The vapor has a significantly lower density than the liquid, so it can always be displaced by the liquid. This accommodates the fact that the heat flux densities at the outer edge of the disc are particularly high, but the liquid is able to absorb high heat flux densities without forming vapor cushions.

[0128] For continuity reasons, the steam is directed into the central region of the disc, where it condenses, as the flue gas is colder near the shafts. The heat flows (absorption and release) are adjusted via the boiling point, the liquid volume, and the gas temperatures so that the absorption flow equals the release flow. Due to the heat release in the outer disc region, the gas is unable, or only to a very limited extent, to perform work on the disc. This means that in this region, heat transfer primarily occurs around the "inner" medium. In the central disc region, the heat is released back to the gas, which, however, involves equivalent work. This means that the gas transfers force to the disc almost isothermally. The process can be ideally represented in the pv and Ts diagrams.

[0129] In a first change of state from state 1 to state 2, the temperature of the flue gas is reduced from T 1 , i.e., the temperature in state 1, to approximately the boiling point Ts. In a real process, a certain small temperature difference would remain between the internal working fluid and the flue gas. Heat transfer occurs isobarically, i.e., without any work being transferred to the disk.

[0130] The heat absorbed by the internal fluid during a first change of state from state 1 to state 2 is released to the flue gas during a change of state from state 2 to state 3, while simultaneously performing work. The work performed in this way is equal to the heat absorbed by the internal fluid between states 1 and 2. This means that the change of state is isothermal.

[0131] Since the flue gas works against a pressure of P0 and the heat is used up to support the isothermal change of state, the change of state from a state 3 to a state 4 results in adiabatic / isentropic relaxation from the pressure P 3 to P 0 -P 4 .

[0132] The corresponding temperature T 4 is higher than that which would occur during complete adiabatic / isentropic expansion between the pressures P 1 and P 0. The temperature difference between T 4 and T 0 is a measure of the minimum energy loss that occurs as a result of heat transfer to the internal fluid. The actual energy losses are even higher because a driving temperature difference is required for the heat transfer itself. The aim is to keep the boiling temperature Ts as low as possible because the strength values ​​of the disk material then increase significantly, which in turn would result in higher disk speeds and thus a reduction in the equipment required for the entire turbine design. The exergy loss itself increases rapidly as Ts approaches the temperature T 4 or T 0. The value T 0 would even require an additional drive. This means that the turbine would come to a standstill. Material problem:

[0133] The strength behavior of metals depends on the temperature.

[0134] The energy absorption capacity of a turbine can be represented by a proportional approach, with strength decreasing progressively with increasing operating temperature. This means that by cooling the turbine disk or (in other designs) the blades, energy absorption can be significantly increased. Cooled disks therefore make it possible to use lightweight materials with low strength without the risk of breakage, and at the same time, the designs of disk turbines, in particular, become significantly more compact.

[0135] Aspects relating to the disc rotor turbine according to the invention: 1. Disks of disk turbines are cooled by an internal fluid circuit in such a way that evaporation occurs in the outer region and condensation occurs in the central region as a result of external heat input and heat removal, preferably through hot flue gases, which are used as the working fluid to generate mechanical energy. 2. The disk shells are connected to one another by sleeves that allow external fastening, thus enabling the combination of several disks. 3. Organic or inorganic fluids and metals can be used as cooling media. 4. Blade elements can also be used instead of disks (radial turbine). Device for converting thermal energy into mechanical energy:

[0136] The previously described largely isothermal expander is part of a closed gas turbine process. The entire process also includes a combustion chamber, which in this case is externalized, and a compressor. This makes it possible to use a suitably adapted working medium such as xenon (preferably) or other noble gases. Noble gases are useful because they are monatomic and incapable of radiating. Radiation from the gas body would lead to increased heat transfer, which poses the risk that the gas body between the turbine disks would cool too quickly and thus be unable to transfer any work to the disks, or only to a very limited extent.

[0137] There are two fundamentally different working models for the operation of the entire process: Isothermal compression at a raised temperature level, such that the working medium is not cooled or cooled to a certain extent after expansion but is compressed, which would enable the use of the remaining energy by external sinks, and isothermal compression at the lowest temperature level, such that the working medium is first cooled after expansion and then compressed, which would lead to a maximization of the thermal efficiency.

[0138] In the first case, a certain amount of residual energy would remain in the working fluid, reducing thermal efficiency, but there would still be thermal energy available to operate external sinks. In principle, however, the gas turbine process can be designed by recuperating the waste heat after expansion so that no second power process would be required, since the power exchangers (disks) are very thermally resilient. This means that gradual operation is possible in both the expander and the compressor. For exergetic reasons, however, only the compressor should be operated in gradual operation. Partially isothermal compression

[0139] The integrals for the technical work to be supplied and the work gained can be read from a pressure-volume diagram, and the corresponding heat integrals for the input and output can be read from the associated temperature-entropy diagram. This is illustrated by way of example in the Figures 8 and 9After partial isothermal compression (change of state from 3 to 4), the working fluid is further compressed isentropically (change of state from 4 to 5) to the final temperature or pressure. Alternatively, compression could be performed completely isothermally (change of state from 3 to 5), although this would require more intensive cooling. The resulting increased cooling energy would be absorbed primarily by the combustion air, which already absorbs the energy from the change of state from 3 to 4. This would result in certain exergetic losses due to transfer losses, but this approach can have design and thus economic advantages. Maximum thermal efficiency

[0140] After isobaric cooling, the working fluid is compressed isothermally. Even here, compression could only be partially isothermal if isentropic compression were allowed to occur in the final phase of this step. This degree of freedom is required to economically optimize the design, as in the case of high-temperature compression. The inlet temperature into the expander could also be varied, but for exergetic reasons, it is advisable to always operate the expander at maximum temperature.

[0141] With the waste heat from the combustion chamber (cf. Fig. 7 ) a second cycle can be carried out, which, however, does not require cooled disc elements, since the temperature level is much lower (cf. Figure 7). However, it is advantageous to conduct this process with xenon or another gaseous working medium with a low heat capacity. This low heat capacity allows the corresponding disk turbine to be designed with an expansion stage. The low-temperature process can also be run in a gradual manner to enable heat extraction for the provision of useful heat. Constructive solutions

[0142] In contrast to expansion, where the temperature of the working medium constantly decreases in isentropic conditions, the temperature constantly increases during isentropic compression. This also tends to apply to the partially isothermal process steps, where, as shown in a pV or Ts diagram, the temperature tends to decrease during expansion in the range from state 0 to state 3. During compression, the temperature increases from state 4 to state 5. This means that during expansion, heat must be added to the working area and, during compression, a corresponding amount of heat must be removed so that isothermal or partially isothermal changes of state can occur. During expansion, the heat is distributed within the disk in such a way that the heat dissipated in the outer area of ​​the disk (far from the shaft) is returned to the inner area (close to the shaft) in equal measure.The "residual area" of the disk, which lies in the near-wave region, allows for isentropic relaxation.

[0143] During compression, this principle of heat distribution would have to be reversed, so that heat would be dissipated in the inner region of the disc and an equal amount of heat would be returned to the working fluid in the upper region. The cooling medium inside the disc forms a two-phase flow. However, since the cooling medium is also subject to centrifugal force, a phase separation would occur such that the liquid portion would be pushed outwards, leaving only vapor in the area near the shaft. This means that the heat distribution requirement cannot be met in this way. However, if the condensation were transferred to another disc system, which corresponds to the compressor on the cooling medium side, the heat distribution problem would be solved.

[0144] The condenser communicating with the compressor is in Figure 2 presented in principle and in Figure 5regarding a possible design with three discs each for evaporation with almost isothermal compression for the working medium around the discs and for condensation when the cooling medium (water, air, etc.) is heated. The selection of a certain number of discs was made for the sake of clarity. The choice of the number of discs depends on general fluid mechanical considerations that are irrelevant for this basic description. The outer disc areas are flowed around by the working medium or by an external cooling medium (ambient air, water from the environment, or another external heat sink). The outer flows are hermetically separated by a separating disc that is guided into the turbine shell at the outer edge. The introduction of the separating disc into the turbine shell symbolizes the sealing effect; alternatively, a frictional connection between the outer disc dimension and the casing could also have a sealing effect, as is common with blade turbines.To demarcate the left and right periphery there are two further dividing discs in . Figure 5 A general illustration of the design principle of the high pressure section of the turbine is largely self-explanatory in Figure 7 shown. Internal cooling mechanism

[0145] In the rotary condenser, the cooling medium has a higher density than in the evaporator or compressor. Similar to a natural circulation boiler, the condenser acts as a downcomer system and the compressor as a riser system, the only difference being that the fluid moves radially due to centrifugal force. In the condenser, the fluid moves outwards away from the shaft axis, is guided through short tubes into the evaporator, where it moves towards the shaft axis. There are holes in the shaft that clear the way into the shaft, allowing the fluid to be returned to the condenser area. The shaft is axially sealed from the environment by orifices. The external cooling medium enters preferentially in the area close to the shaft, where the internal cooling medium still has a high vapor content. This makes the condensation effect more pronounced than with the reverse process.The compressor operates at a roughly constant temperature, as does the internal cooling medium, which is in the evaporating state. Due to the increasing density of the working medium, there is an increased heat flux, or heat transfer, to the internal cooling medium, which is compensated for by increased vapor formation, keeping the temperature difference constant across the entire compression range. rotary capacitor

[0146] The rotary condenser is fully integrated into the turbine casing, which consists of two eccentrically arranged half-shells. The rotary condenser draws in ambient air, which is accelerated to rotational speed by helically shaped, fixed blades arranged around the shaft. This creates a suction effect and prevents acceleration losses at the discs. The air exits the rotary condenser through tangentially aligned openings on the outer edge of the turbine casing. In principle, a cooling liquid could also be drawn in, but this would have the disadvantage that the temperature increase would be rather small, because it is difficult to manage the necessarily small mass flows in such a way that a sufficiently good heat transfer is possible. In addition, the supply of liquids must be carefully sealed.The condenser discs must be spaced as far apart as possible to minimize the amount of work being applied to the fluid. The amount of work applied should be large enough to compensate for the pressure loss in the downstream external heat exchanger. At the same time, heat transfer must be sufficiently large to maintain a sufficiently small heating surface. Ultimately, the design requires economic optimization. Completely externalizing the cooling system, i.e., not enclosing it around the shaft and connected to it, is rather disadvantageous, as this would require the internal cooling medium to be diverted into a fixed structure. This would require special sealing due to the combination of a stationary structure (heat exchanger) with a rotating structure.

[0147] The inner cooling medium may experience a deceleration on its way to the outer edge due to the Coriolis effect. This means that the sum of the resulting Coriolis forces can have a driving effect on the turbine.

[0148] This means that work would have to be performed to compensate for this effect. This work input can be avoided by equipping the discs with radially oriented steering elements or steering grooves that prevent tangential movement. Rotary compressor

[0149] Like the rotary condenser, the rotary compressor is fully integrated into the housing. The rotary compressor receives the expanded working fluid near the shaft, i.e., it is located directly next to the expander. The compressed working fluid, like the external cooling medium, leaves the compressor via tangentially oriented openings at the end of the two eccentric headers and is fed to the combustion chamber for heating.

[0150] On its way from the outer edge of the disc towards the shaft, the internal cooling medium experiences a tangential acceleration due to the Coriolis effect, which leads to the transfer of work to the disc. The work source is caused by tangential friction. In this way, at least part of the compressor work can be compensated. At the inlet to the discharge openings in the shaft, the Coriolis velocity (advance of the medium in the tangential direction) is converted into pressure energy, as the fluid must comply with the steering constraints of the design. The holes should preferably be designed so that there is no excessive shock loss in the downstream flow behind the holes. The inlet to the rotary condenser should preferably be designed so that a certain advance is created at the inlet in order to reduce the work absorption of the fluid (see Figure 4 . External devices

[0151] The external devices consist of the recuperator for the return of thermal energy from the high-temperature compressor, which is first absorbed by the coupled rotary cooler. The external cooling medium is preferably ambient air, which is also used as combustion air in the combustion chamber (see Figure 7 Alternatively, when operating with a low-temperature compressor, an external recuperator is required to integrate the waste heat after the expansion vessel into the combustion air. The external cooling medium for cooling the low-temperature compressor preferably consists of ambient air, which is discharged to the environment as thermal waste.

[0152] In any case, preheated combustion air is preferably supplied to the combustion chamber. The working medium is preferably inert gas, which is heated to operating temperature using the waste heat from the combustion chamber. Recuperator for using the waste heat after expansion

[0153] This recuperator is preferably a corner-tube heat exchanger with a counterflow circuit. Ambient air is passed through the tubes, and the working fluid circulates around them. This ensures that the working fluid is not contaminated by dust. waste heat exchanger

[0154] The waste heat exchanger consists of a radiant chamber whose walls are cooled by the working fluid, and a convective section, which is designed like a recuperator. This means that the working fluid flows through the tubes and the flue gas flows around them. The flue gas is cooled almost to ambient temperature. A condensing unit can be added to save fuel. combustion chamber

[0155] The combustion chamber is generally operated with any fuel. It can therefore be equipped with a solid fuel furnace or a burner for fluid fuels. The walls of the combustion chamber are preferably cooled with the process media available or constructed of refractory material. Plant flow diagram according to Figure 7

[0156] The plant flow diagram illustrates a sliding operation. This means that compression occurs at a higher temperature level to allow for the extraction of heat for external use (combined heat and power). The numerical values ​​for temperatures and pressures given below are examples and can vary considerably depending on application requirements.

[0157] Fuel and preheated air are fed into the fictitiously adiabatic combustion chamber, where the flue gas formed there exits the combustion chamber at approximately 2000°C. In a downstream waste heat exchanger, which is partially structurally connected to the combustion chamber walls for cooling, the flue gas is first cooled to 500°C, then fed to an economizer for heating the working fluid of the low-pressure turbine. The flue gas is discharged into the stack at 100°C.

[0158] The heat released from the flue gas is used to heat the working fluid, which enters the waste heat exchanger at 400°C and exits at 1500°C. The working fluid is preferably xenon. The working fluid is pressurized to 15 bar, not taking into account minimal pressure differences that occur during transport. In the expander, the working fluid is reduced to a pressure of 1 bar, while simultaneously reducing its temperature to 400°C. The expansion process occurs partially or completely isothermally at an operating temperature higher than 400°C, but not at temperatures higher than the inlet temperature of the working fluid. The operating temperature level depends on the selected cooling medium and the material of the expander discs. The released shaft energy is transferred to a generator, where it is converted into electrical energy.Within the expansion stage, the working fluid is first lowered to a working temperature, with the dissipated heat being fed back into the working fluid during the actual expansion. In this way, the temperature remains virtually constant during expansion. The final phase of expansion occurs almost isentropically in order to minimize exergetic losses. The working fluid is further cooled in an air preheater at roughly the same pressure to a level of 80 to 200°C, after which it enters the compressor stage. In the compressor, the pressure is increased isothermally to 15 bar, although the pressure increase in the final phase of this process step can also occur isentropically; accordingly, the temperature would rise by a certain amount. The extent to which this is permitted depends on the disc material used in the compressor and the acceptable exergetic loss with regard to heat transfer.The compressor disks are cooled by a fluid circulating internally within the disks. This fluid transfers its heat to a heat transfer medium from the environment. The compressed working fluid is ultimately fed to the waste heat exchanger, thus completing the fluid cycle.

[0159] The combustion air is fed into the combustion chamber after leaving the air preheater at a temperature of 80 to 180°C. An additional cooling stream from an external source—the return flow of a useful heat sink with a temperature of up to 150°C—is required to transfer the waste heat from the compressor stage to the supply line of the useful heat sink. The temperature of this medium rises to up to 350°C in the supply line. Low-pressure turbine cycle

[0160] The flue gas leaves the combustion chamber at a temperature of 500°C. It is advisable to use this temperature level in a second gas turbine operating at low pressure. The low-pressure turbine, like the high-pressure turbine, consists of an expander operating at 400°C and 5 bar and an isothermal compressor with outlet parameters of 50°C and 5 bar. This expander is also designed with cooled discs, like the one in the high-pressure section. The waste heat from the expander is used to heat the combustion air from 10°C to 80°C in a low-temperature preheater. The ambient air is supplied at 10°C, so the xenon can be cooled (preferably) to 20°C. The cooling flow required for the low-pressure compressor comes from the environment and is thermally worthless. The low-temperature turbine could also be operated in planing mode to extract process heat.

[0161] As an alternative to the low-temperature gas turbine, a Rankine cycle could also be designed. This would have the advantage of generating steam that could be useful for special process purposes.

[0162] Aspects of the overall plant according to the plant flow diagram in Figure 7 1. A gas turbine process is provided consisting of a high-pressure and a low-pressure stage, with the expander and compressor each having disc designs, which in the case of the high-pressure stage contain internally cooled discs. The compressor of the high-pressure stage contains an evaporating medium that is directly combined with a rotary condenser, and the rotary evaporator is cooled by an external medium. In the high-pressure stage, a noble gas with low thermal conductivity and low specific heat capacity is used as the working medium, with the noble gas being heated by an external heat source. 2. The external heat source is a combustion chamber with cooled or uncooled walls, in which a gaseous, liquid, or solid fuel is burned with air as the oxygen source, and the walls are cooled by the working medium of the high-pressure stage.Downstream of the combustion chamber is an economizer in which the flue gases from the combustion chamber are further cooled and release their heat to the working medium of the low-pressure stage, whereby the working medium is preferably a noble gas with a low heat capacity. 4. Instead of the low-pressure stage consisting of expander and compressor, a steam turbine with a feed pump is used, each of which is preferably a disc design. The steam turbine can be multi-stage and there are return areas between the individual stages in which the steam is directed to the circumference of the discs. 5. The outlet openings of the discs closest to the shaft in the last stage of a multi-stage turbine or a single-stage turbine are offset from one another in such a way that the escaping gas flow is swirl-free, such that the offset angle with respect to the direction of rotation of the disc is negative. 6. As an alternative to the previous point 5, the working medium cancan also be directed outwards through longitudinal grooves in the shaft, whereby the grooves are twisted helically against the direction of rotation to cancel out the swirl at the gas outlet. 7. The discs of the high-pressure flash vessel are hollow on the inside so that an evaporating medium can behave in such a way that it evaporates in the outer, hot area and condenses in the inner, cold area. The working medium flowing outwards initially evaporates without releasing any work on its way from the outer to the inner edge of the disc without releasing any work and then absorbs heat when releasing work. The work is released isothermally, with the inner condensate film flowing back outwards due to centrifugal force. Optionally, a certain distance in the area close to the shaft is uncooled so that residual isentropic expansion can occur. 8.The discs of the high-pressure compressor are also hollow inside and are connected to a rotary heat exchanger, which also consists of hollow discs, by the shaft and by pipes located on the outer edge of the discs, whereby the rotary heat exchanger is cooled by an external working medium that flows around the outside of the discs of the rotary heat exchanger.

[0163] The effect of the disc rotor turbine according to the invention is that, due to the cooling of the disc, it is exposed to relatively low thermal stress, allowing a variety of materials to be used to form the respective disc body, including materials with low density and therefore low weight. In particular, discs made of materials with very low density can be rotated at very high speeds due to their resulting low mass moment of inertia, allowing the turbine to operate at high speeds and thus with high efficiency.

[0164] The effect of the device according to the invention for converting thermal energy into mechanical energy is, in particular, that due to the high efficiency of the integrated disc rotor turbine, the entire device can also be operated with a high efficiency, so that a relatively low thermal or chemical energy input is necessary to provide the desired amount of mechanical or electrical energy. List of reference symbols

[0165] Disc rotor turbine 10 disc 11 Gas intake chamber 12 Disc body of the disc 13 Window opening 131 cavity of the disc 14 space between panes 15 Cooling medium 16 gaseous cooling medium 161 liquid cooling medium 162 first cooling medium flow 163 second cooling medium flow 164 Gas, gas volume flow 17 compressor unit 20 Compressor disc 21 Compressor gas intake chamber 22 Gas volume flow inlet 221 Gas volume flow outlet 222 Gas volume flow transition 223 Disc body of the compressor disc 23 Compressor disc cavity 24 Shaft area covered by compressor disc 25 Cooling unit 30 Cooling disc 31 Coolant chamber 32 Coolant inlet 321 Coolant leak 322 Disc body of the cooling disc 33 Cooling disc cavity 34 Shaft area covered by cooling disc 35 coolant 37 Separating element 41 crossbar 42 hollow connecting space 43 opening 44 Wave section limitation 45 axis of rotation 50 rotation 501 Wave 51 Housing 52 Sealing 53 first heat exchanger 61 second heat exchanger 62 third heat exchanger 63 heat sink 64 fourth heat exchanger 65 Chimney 66 combustion chamber 67 generator 68 Low pressure range 70 Low-pressure compressor 71 Low-pressure expansion vessel 72 High pressure area 80 High-pressure compressor 81 High-pressure expansion vessel 82 first working medium 100 heated first working medium 101 relaxed first working medium 102 cooled first working medium 103 compressed first working medium 104 second working medium 200 heated second working medium 201 relaxed second working medium 202 cooled second working medium 203 compressed second working medium 204 Combustion air 300 Ambient air 301 reheated combustion air 302 preheated combustion air 303 Heat transfer medium 400 cool heat transfer medium 401 warm heat carrier 402 flue gas 600 cooled flue gas 601

Claims

1. A tesla-type turbine (10) for converting the enthalpy of a gas volume flow (17) into mechanical energy, comprising at least one disk (11) which is arranged on an axis of rotation (50) and which can be set in rotation (501) with a gas volume flow (17) flowing substantially tangentially towards it, so that mechanical energy can be removed at a shaft (51) coupled to the disk (11), wherein the tesla-type turbine (10) comprises at least one gas receiving chamber (12) for receiving and discharging the gas volume flow (17) flowing at least partially tangentially to the disk (11), and wherein a disk body (13) forming the disk (11) comprises at least one cavity (14), characterized in that a cooling medium (16), in particular a cooling liquid, is received or can be received in the cavity for the purpose of cooling the disk body (13).

2. The tesla-type turbine (10) for converting the enthalpy of a gas volume flow (17) into mechanical energy according to claim 1, characterized in that the disk (11) is apparatus for at least partially evaporating cooling medium (16) received in its cavity (14) when heat is supplied to the disk (11) from the gas volume flow (17) flowing towards the disk (11) in the cavity (14).

3. A method for operating a tesla-type turbine (10) for converting the enthalpy of a gas volume flow (17) into mechanical energy according to one of claims 1 and 2, characterized in that a gas volume flow (17) is fed to the disk (11) essentially tangentially, so that the disk (11) is set in rotation (501) due to friction.

4. The method for operating a tesla-type turbine (10) for converting the enthalpy of a gas volume flow (17) into mechanical energy according to claim 3, characterized in that heat of the gas volume flow (17) is transferred to the cooling medium (16) in the cavity (14) of the disk body (11), so that the cooling medium (16) at least partially evaporates.

5. An apparatus for converting thermal energy into mechanical energy, characterized by a tesla-type turbine (10) according to at least one of claims 1 and 2, wherein the disk (11) of the tesla-type turbine (10) is arranged coaxially on a shaft (51), and wherein the shaft (51) is mechanically connected to a compression unit (20) which comprises at least one compression disk (21) connected to the shaft (51) in a rotationally fixed manner, so that when the tesla-type turbine (10) is set in rotation (501), the compression disk (21) can be set in rotation (501) and wherein the compression unit (20) comprises a compressor gas receiving chamber (22), which is fluidically connected to the gas receiving chamber (12) of the tesla-type turbine (10), so that gas (17) compressed by the compression unit (20) can be fed to the tesla-type turbine (10), in particular to the gas receiving chamber (12) of the tesla-type turbine (10).

6. The apparatus for converting thermal energy into mechanical energy according to claim 5, characterized in that the compression disk (21) has at least one cavity (24) in a disk body (23) forming the compression disk (21), wherein the cavity (14) of at least one disk (11) of the tesla-type turbine (10) is fluidically connected to the cavity (24) of at least one compression disk (21), so that cooling medium (16) present at least partially in gaseous phase can be fed from the cavity (14) of the disk (11) of the tesla-type turbine (10) to the cavity (24) of the compression disk (21).

7. The apparatus for converting thermal energy into mechanical energy according to one of claims 5 and 6, characterized in that the compression disk (21) is connected in a rotationally fixed manner to a rotatable cooling unit (30), wherein the cooling unit (30) comprises at least one cooling disk (31) which is arranged coaxially on a cooler shaft which is connected in a rotationally fixed manner to the shaft (51) of the tesla-type turbine (10), and wherein the cooling disk (31) comprises at least one cavity (34) in the disk body (33) forming the cooling disk (31) and the cavity (34) of the cooling disk (31) is fluidically connected to the cavity (24) of the compression disk (21), so that cooling medium (16) heated in the compression unit (20) can be fed to the cooling unit (30), by means of which the cooling medium (16) can be cooled in the cooling disk (31) of the cooling unit (30) and can be returned from the latter to the compression disk (21) of the compression unit (20).

8. The apparatus for converting thermal energy into mechanical energy according to claim 7, characterized in that at least a first fluidic connection between the cavity (24) of the compression disk (21) and the cavity (34) of the cooling disk (31) is realized by means of at least one transverse web (42) through which flow can pass and which is arranged essentially axially parallel to the axis of rotation (50) of the shaft (51) between the compression disk (21) and the cooling disk (31).

9. The apparatus for converting thermal energy into mechanical energy according to one of claims 7 and 8, characterized in that at least a second fluidic connection between a cavity (24) of at least one compression disk (21) and a cavity (34) of at least one cooling disk (31) is realized by means of a hollow connecting space (43) in a shaft section, which extends from a shaft region (25) covered by a compression disk (21) to a shaft region (35) covered by a cooling disk (31), wherein the covered shaft regions each comprise axially at least one opening (44) for the purpose of realizing a flow of the cooling medium (16) into and out of the hollow connecting space (43) of the shaft (51) into and out of the cavity (24) of the compression disk (21) and / or into and out of the cavity (34) of the cooling disk (31).

10. A method for converting thermal energy into mechanical energy, in which, in an apparatus for converting thermal energy into mechanical energy according to at least one of claims 5 - 9, the method for operating a tesla-type turbine (10) according to one of claims 3 or 4 is carried out, wherein, in at least one compression disk (21), in particular the cavity (24) of a compression disk (21), heated cooling medium (16) is fed to at least one cooling disk (31), in particular from the cavity (34) of a cooling disk (31), and is cooled there, and after the cooling medium (16) has cooled down, it is again supplied to a compression disk (21).

11. A method for converting thermal energy into electrical energy, wherein the method for converting thermal energy into mechanical energy is carried out according to claim 10 and kinetic energy of the rotating shaft (51) is converted into electrical energy by means of a generator (68).