System for using heat, and method for operating a system for using heat

Abstract

The present invention relates to a system (1) for using heat, comprising at least one heat engine (2) and at least one heat exchanger unit (3), wherein a pressurized, non-combustible fluid can be applied to the heat engine (2) in order to expand the fluid, and wherein thermal energy can be transferred to the fluid by means of the heat exchanger unit (3). The heat exchanger unit (3) is designed such that a specific thermal energy can be supplied to the fluid using the heat exchanger unit (3) at least at the nominal mass flow of the fluid, said thermal energy being at least 80% of the isentropic enthalpy gradient of the heat engine (2) multiplied by the efficiency of the heat engine (2) at nominal mass flow.

Description

[0001] P45660PC00 / V / V ​​29.11.2025

[0002] 1

[0003] TURBONIK GmbH, Doncaster-Platz 5-7, 45699 Herten

[0004] "Plant for the utilization of heat and method for the operation of a plant for the utilization of heat"

[0005] The invention relates to a system for utilizing heat, comprising at least one heat engine and at least one heat exchanger unit, wherein the heat engine can be supplied with a pressurized, in particular non-flammable, fluid in order to expand the fluid, and wherein heat energy can be transferred to the fluid by means of the heat exchanger unit.

[0006] The efficient use of waste heat from industrial processes is an essential component of sustainable energy use. Micro steam turbines offer a solution for converting unused waste heat into mechanical or electrical energy, particularly in small to medium power ranges up to 2 MW. Waste heat, generated, for example, in the form of hot water or steam, is used to produce live steam in a steam generator. This steam is then expanded in the micro steam turbine, where the contained thermal energy is converted into mechanical work. The mechanical energy can be used directly or converted into electrical energy by a generator.

[0007] With the increasing focus on energy efficiency and decarbonization, the use of micro steam turbines will continue to grow in importance. Advances in materials science, miniaturization, and efficiency improvements make them a key technology for the energy transition in industrial and commercial processes.

[0008] The invention is therefore based on the objective of providing a system and a method for operating a system with which thermal energy, in particular waste heat from an industrial process, can be used with high efficiency. P45660PC00 / V / V ​​29.11.2025

[0009] 2

[0010] The aforementioned problem is solved in a generic system with the features of claim 1, namely by designing the heat exchanger unit such that, at nominal mass flow rate, the fluid can be supplied with a specific heat energy that is at least 80%, and in particular at least 90%, of the isentropic enthalpy drop of the heat engine multiplied by the efficiency of the heat engine at nominal mass flow rate. The efficiency is, in particular, the isentropic efficiency of the heat engine.

[0011] The system preferably comprises a piping system in which the pressurized fluid is conveyed. The heat engine is arranged within the piping system and can be subjected to at least a portion of the fluid's mass flow. The piping system preferably includes a plurality of shut-off and / or control valves, which are particularly controllable by a control unit of the system. The control unit particularly includes at least one data processing unit with at least one processor and at least one, preferably non-volatile, memory. The data processing unit interacts, for example, via interfaces with the shut-off and / or control valves to actuate them.

[0012] The heat engine is preferably a turbine, for example a radial turbine or an axial turbine. Particularly preferably, the heat engine is a steam turbine, especially a micro steam turbine, preferably designed as an axial turbine. Other heat engines that are particularly suitable include piston expanders, screw expanders, scroll expanders, Wankel expanders, rotary piston expanders, or free-piston expanders. The heat engine is coupled, for example, to at least one driven machine, such as at least one generator or at least one compressor. P45660PC00 / V / V ​​29.11.2025

[0013] 3

[0014] In particular, the generator and / or compressor is integrated into the system in such a way that waste heat from the generator and / or compressor is used to heat heat sinks, for example, to preheat air or condensate. This measure can increase the efficiency of the heat utilization process.

[0015] Preferably, the system is part of an open process in which the fluid flowing through the system is used as a process medium in an application, particularly one independent of the system itself, e.g., as a heat transfer medium. For example, it is provided that there is only an indirect relationship between the mass flow of the fluid and the heat source, for example, via a higher-level system control. For example, the relationship exists only because the load case is the same. Thus, the fluid is not circulated in a closed loop within the system. In particular, the fluid flows through the heat engine only once.

[0016] Alternatively, the fluid in the system is circulated in a closed loop, specifically by flowing through the heat engine multiple times. If the fluid is used, for example, as a heat transfer medium, heat is transferred downstream of the heat engine to another system where a heat-requiring process is carried out, and the condensate is returned to the steam generator. In embodiments of the system where the fluid is circulated in a closed loop, particularly with steam as the fluid, the cycle efficiency is defined as the ratio of the heat engine's power output to the heat input. This corresponds, in particular, to the ratio of the superheat to the heat input. Preferably, the cycle efficiency of the system operated with steam as the fluid is less than 20%.

[0017] The heat, which can also be referred to as secondary heat, is, for example, thermal energy that arises as waste heat in an industrial process, such as thermal energy from a P45660PC00 / V / V ​​29.11.2025

[0018] 4

[0019] A post-combustion process or a chemical process. Furthermore, it is specifically stipulated that the heat source is a solar thermal plant, a geothermal plant, or a biomass plant. The heat or secondary heat that can be supplied to the fluid via the heat exchanger unit is thus distinct from the thermal energy contained in the mass flow of the fluid, which can be referred to as primary heat. For example, the available heat output of the secondary heat source is volatile, so that it is particularly unpredictable at what time how much heat will be available. Furthermore, it is stipulated that the secondary heat source has a substantially constant heat output. In particular, it is stipulated that the heat source has a maximum continuous heat output, i.e., a heat output that is available for the majority of operating hours.

[0020] Alternatively or additionally, the heat or secondary heat used is heat that is present, particularly in limited quantities, in a heat storage device. This could be, for example, a solid heat storage device such as rock, volcanic gravel, limestone, concrete, rock salt, sand, or ceramics, a liquid heat storage device, or a latent heat storage device. It is preferably provided that the heat storage device is part of the system according to the invention. Furthermore, it is preferably provided that the heat storage device is designed as a sensible heat storage device, i.e., it changes only its temperature, but not its phase.

[0021] The fluid is, for example, steam, in particular water vapor. Preferably, the steam is generated in a steam generator and conveyed through a piping system. The system according to the invention is integrated into the piping system. For example, the system according to the invention has at least one steam generator. In particular, the steam generator is provided in addition to the heat exchanger unit. Preferably, the steam generator is not part of the heat exchanger unit. For example, the heat exchanger unit is designed as a superheater. P45660PC00 / V / V ​​29.11.2025

[0022] 5

[0023] Preferably, the heat engine is designed for a nominal mass flow rate between 0.5 t / h and 25 t / h, in particular for steam, preferably water vapor.

[0024] Furthermore, the fluid is provided to be a hydrofluorocarbon or a fluorocarbon, or a mixture thereof. It is also provided that the fluid is, for example, a gas, preferably nitrogen, oxygen, air, or carbon dioxide. If the fluid is nitrogen or oxygen, it preferably originates from a pressure swing adsorption (PSA) system upstream of the present system. Preferably, the present system includes a PSA system.

[0025] In an alternative configuration of the system, the heat engine can also be operated with a fluid, in particular a flammable fluid. The system, and especially all its components, is / are then designed and configured for use with a flammable fluid. The fluid could then be, for example, a flammable gas, such as hydrogen, or a hydrofluoroolefin.

[0026] In exemplary embodiments of the system, it is particularly preferred that the fluid is gaseous upon entering the heat exchanger unit.

[0027] The heat exchanger unit preferably comprises at least one, or at least two, or at least three heat exchangers. Preferably, at least one heat exchanger is arranged upstream of the heat engine and / or at least one heat exchanger is arranged downstream of the heat engine. For example, the heat exchanger unit comprises at least one heat exchanger circuit in which heat is transferred from a heat source, e.g., a heat storage device or a waste heat source, to a heat exchanger medium of the heat exchanger unit. The thermal energy present in the heat exchanger circuit of the heat exchanger unit can be transferred to the fluid by means of the at least one heat exchanger. (P45660PC00 / V / V ​​29.11.2025)

[0028] 6. The heat transfer medium is preferably a vegetable, mineral oil-based, or synthetic thermal oil, e.g., a silicone oil, water or a water-glycol mixture, an organic heat transfer medium, e.g., an organosilicon heat transfer medium, a salt mixture of alkali / alkaline earth metal nitrates or halides, a high-melting-point special salt (fluorides), a molten metal, or a gas. In particular, it is intended that the specific heat capacity of the heat transfer medium corresponds approximately to the specific heat capacity of the fluid.

[0029] For example, the heat exchanger unit has at least one heat control device with which, in particular, the heat output of the heat exchanger unit for heating the fluid, especially the at least one heat exchanger, can be controlled. The heat control device preferably allows the mass flow rate of a heat exchange medium and / or the flow area of ​​the at least one heat exchanger and / or other parameters to be set, which influence the heat output of the at least one heat exchanger and / or the amount of heat in the heat exchange medium. For example, the heat control device includes at least one modulating pump and / or a bypass for the heat exchange medium with which the transfer of thermal energy at the heat source to the heat exchange medium can be influenced. Furthermore, it is provided that the heat exchanger unit has at least one intermediate heat storage unit, e.g.The system includes a solid or liquid storage unit that can be heated if, for example, there is insufficient fluid mass flow to dissipate a sufficient amount of heat from the heat exchanger unit. The intermediate heat storage unit is designed, for example, like one of the heat storage units described above. The heat control device is preferably part of the system's control unit or at least controllable by the system's control unit.

[0030] The present invention is based on the understanding that through innovative

[0031] Coupling of a mass flow of a fluid intended for further use P45660PC00 / V / V ​​29.11.2025

[0032] 7. The system must be relaxed, and the use of thermal energy, for example from a waste heat source or a heat storage system, allows the thermal energy to be converted with very high efficiency, for example into electrical energy. The operation of a described system and / or the execution of a described process can also be referred to as "isenthalpy turbine operation".

[0033] Industrial plants often contain fluid flows of non-flammable fluids that are reduced to a lower pressure level for a specific application, for example, via a throttle. These fluids are used as process media, for instance, for heating in other applications. Furthermore, such plants often have low-energy heat sources available that frequently go unused.

[0034] The invention is based on the understanding that the thermal energy present in a heat source can be utilized with high efficiency if a heat engine is integrated into an existing pressure stage in a fluid within a system, and the fluid is supplied with essentially the same specific thermal energy from the heat source that is extracted from the fluid by the heat engine. With respect to the thermal energy contained, the mass flow rate of the fluid remains essentially unchanged when comparing the inlet and outlet of the system; however, the available thermal energy has been converted by the heat engine for use. The mass flow rate of the fluid is, in a sense, only temporarily used for this conversion. Preferably, the mass flow rate of the fluid serves only temporarily as a carrier of the thermal energy from the heat exchanger unit or the heat source to the heat engine.

[0035] In particular, sensible heat is supplied to the mass flow, especially by means of the heat exchanger unit. P45660PC00 / V / V ​​29.11.2025

[0036] 8

[0037] According to the invention, the heat exchanger unit is designed such that, at least at nominal mass flow rate, the fluid can be supplied with thermal energy that is at least 80%, in particular at least 90%, preferably at least 100% of the isentropic enthalpy drop of the heat engine multiplied by the efficiency of the heat engine at nominal mass flow rate, particularly the isentropic efficiency. The nominal mass flow rate is the reference value for the optimal utilization of the turbine under defined conditions. In particular, the nominal mass flow rate is the mass flow rate for which the heat engine is designed at full load. The nominal mass flow rate of the heat engine denotes the quantity of working fluid (e.g., steam, gas, or liquid) that flows through the turbine per unit of time under nominal conditions. The nominal mass flow rate particularly characterizes the intake limit of the heat engine, which defines the maximum mass flow rate that a heat engine can handle.

[0038] For example, it is provided that the heat exchanger unit is designed such that, at least at nominal mass flow rate, a maximum heat energy can be supplied with the heat exchanger unit that is 110%, in particular 120%, of the isentropic enthalpy gradient of the heat engine multiplied by the, in particular isentropic, efficiency of the heat engine at nominal mass flow rate.

[0039] It has proven advantageous if, in particular, the system is provided with at least one control device, and if the control device can regulate at least the specific amount of heat transferred to the fluid by the heat exchanger unit. Preferably, the control device is designed and configured to cause the heat exchanger unit, at least at the nominal mass flow rate of the fluid, to transfer a specific amount of heat to the fluid that is at least 80%, in particular at least 90%, and in particular at least 100%, of the isentropic enthalpy drop of the heat engine multiplied by the efficiency of the heat engine at nominal mass flow rate. P45660PC00 / V / V ​​29.11.2025

[0040] 9

[0041] Preferably, the control device is designed and configured to regulate the supply of heat energy via the heat exchanger unit as a function of a target temperature downstream of the heat engine, in particular at the outlet of the heat engine or downstream of a heat exchanger. Preferably, the target temperature is the temperature that would result from an isenthalpic throttling of the fluid to the same pressure as at the outlet of the heat engine.

[0042] For example, it is planned that sensible heat is supplied upstream and / or downstream of the heat engine. Sensible heat only leads to a temperature change, not a phase change. In particular, the sensible heat is supplied by means of the heat exchanger unit.

[0043] It is particularly preferred that a control device of the system is designed and configured such that the mass flow of the fluid through the heat exchanger unit receives essentially the same specific amount of heat as is extracted from the fluid by the heat engine. In this case, the heat balance of the portion of the mass flow that passes through the heat engine essentially corresponds to the heat balance of an isenthalpic throttling of the same mass flow to the same pressure. This approach allows the mass flow of the fluid downstream of the heat engine to continue to be used as a process medium, e.g., as a heat transfer fluid with predefined parameters, while simultaneously converting the thermal energy from the heat source into kinetic energy by the heat engine.At least at the nominal mass flow rate of the fluid, and preferably also at all other mass flow rates, the heat exchanger unit supplies the mass flow of the fluid with at least the specific heat energy that is subsequently extracted from the mass flow at the then prevailing efficiency of the heat engine. P45660PC00 / V / V ​​29.11.2025.

[0044] 10

[0045] Alternatively or additionally, it is provided that the control device is designed and configured to regulate the transfer of heat energy to the fluid with the heat exchanger unit as a function of the mass flow rate and the specific heat output available in the heat exchanger unit, such that at least 80%, in particular at least 90%, of the specific heat energy is supplied to the mass flow rate of the fluid, with sufficient heat output of the heat exchanger unit. This specific heat energy is extracted from the portion of the mass flow rate of the fluid passing through the heat engine, multiplied by the isentropic enthalpy gradient at a given efficiency.

[0046] Alternatively or additionally, the control device is designed and configured to regulate the transfer of heat energy to the fluid with the heat exchanger unit as a function of the mass flow rate and the specific heat output available in the heat exchanger unit, such that if the heat output of the heat exchanger unit is insufficient, only that portion of the mass flow rate is directed through the heat engine to which at least 80%, in particular at least 90%, preferably at least 100%, of the specific heat energy is supplied, which is extracted from the mass flow rate at a given efficiency multiplied by the isentropic enthalpy gradient of the heat engine.

[0047] If a different fluid temperature is desired downstream of the heat engine than the temperature that would result from isenthalpic throttling of the fluid to the same pressure, the amount of heat transferred to the fluid via the heat exchanger unit can be modified depending on the desired target temperature. Advantageously, the magnitude of the supplied heat energy always remains on the order of the heat energy extracted from the mass flow of the fluid in the heat engine.

[0048] If the desired target temperature downstream of the turbine is above the temperature that would result from the isenthalpic throttling of the fluid mass flow used as a reference, the control device is preferably designed for this purpose. P45660PC00 / V / V ​​29.11.2025

[0049] 11. The control device is designed and configured to cause the heat exchanger unit to increase the specific heat energy transferred to the fluid above the specific heat energy extracted by the heat engine, so that the increased target temperature is achieved. If the desired target temperature downstream of the heat engine is below the temperature that would result from the isenthalpic throttling of the mass flow of the fluid used as a reference, the control device is preferably designed and configured to cause the heat exchanger unit to reduce the specific heat energy transferred to the fluid below the specific heat energy extracted by the heat engine, so that the reduced target temperature is achieved.

[0050] For example, it is provided that the control device is designed and configured to regulate the specific heat energy transferred to the mass flow by the heat exchanger unit in such a way that the mass flow is supplied with the specific heat energy that essentially corresponds to the isentropic enthalpy gradient of the heat engine multiplied by the efficiency of the heat engine at the respective mass flow, in particular at the nominal mass flow, or that the mass flow is supplied with the specific heat energy that essentially corresponds to 80%, in particular essentially 90%, of the isentropic enthalpy gradient of the heat engine multiplied by the efficiency of the heat engine at the mass flow, in particular to reduce the target temperature, or that the mass flow is supplied with the specific heat that essentially corresponds to 120%, in particular 110%,the isentropic enthalpy gradient of the heat engine multiplied by the efficiency of the heat engine at the mass flow rate, in particular to increase the target temperature.

[0051] The specific thermal energy extracted from the mass flow of the fluid by the heat engine is determined in particular by the design of the heat engine, especially for the nominal mass flow of the fluid. According to the invention, it is therefore provided that the P45660PC00 / V / V ​​29.11.2025 heat engine can be controlled by influencing the mass flow of the fluid supplied by the heat exchanger unit.

[0052] The specific thermal energy of the fluid can be controlled by determining whether the state of the fluid downstream of the heat engine essentially corresponds to that of an isenthalpic throttling (without a heat engine), i.e., whether exactly the heat extracted by the heat engine is equal to the heat supplied, or whether more or less thermal energy is contained in the mass flow compared to an isenthalpic throttling. The crucial target variable here—as described above—is the temperature of the fluid downstream of the heat engine. Depending on a desired target temperature of the mass flow downstream of the heat engine, slightly more or less thermal energy can therefore be introduced into the mass flow during operation of the system than is extracted by the heat engine. For example, the effects of losses in the system, such as those caused by poorly or uninsulated pipework, are to be disregarded in this analysis.If the losses reach a predetermined threshold, e.g., ± 10% or ± 20% of the added, in particular specific, thermal energy, these must also be taken into account in the analysis.

[0053] Optionally, for example, the control device is designed and configured to adjust the rotational speed of the heat engine to change the efficiency, in particular to maintain a constant temperature at the outlet of the heat engine when the heat exchanger unit's thermal output is too low, and / or to adjust the geometry of the heat engine, e.g., via an adjustable nozzle geometry, to influence the mass flow rate and / or the efficiency of the heat engine, and / or to change the inlet pressure and / or outlet pressure of the heat engine and thus the isentropic enthalpy gradient.

[0054] The invention offers an advantage over the prior art in that heat or secondary heat can be utilized with high efficiency when the thermal energy is introduced into an existing mass flow of a fluid to be depressurized and then extracted again using a heat engine. Furthermore, the supplied thermal energy can be controlled. P45660PC00 / V / V ​​29.11.2025

[0055] 13 a desired target temperature of the fluid downstream of the heat engine, in particular at an outlet of the system, is set.

[0056] One embodiment of the system provides for at least one control device and at least one bypass, wherein the bypass is arranged parallel to the turbine and is designed to reduce the fluid pressure, particularly to a target pressure. The mass flow of the fluid can be routed either completely or partially through the heat engine and / or completely or partially through the bypass. The control device preferably includes actuating and / or regulating valves with which the application of the mass flow of the fluid can be adjusted. The control device is preferably designed and configured such that the proportion of the mass flow of the fluid routed through the heat engine and / or the bypass can be regulated at least as a function of, for example, the current or predicted heat output of the heat exchanger unit.

[0057] Such a system is particularly advantageous when the secondary heat is based on a volatile heat source whose heat output fluctuates. Consequently, if there is temporarily insufficient thermal energy available to introduce enough heat energy into the mass flow at a given mass flow rate to compensate for the heat energy extracted by the heat engine or to set a target temperature downstream of the heat engine, at least the portion of the mass flow that cannot be sufficiently heated is diverted via the bypass parallel to the heat engine.

[0058] Particularly with volatile heat sources, it has proven advantageous to reduce the proportion of the mass flow routed through the heat engine when the current heat output of the heat exchanger unit is lower than the specific heat energy that is removed from the mass flow by the heat engine at the respective efficiency. Preferably, only the portion corresponding to the P45660PC00 / V / V ​​29.11.2025 is then routed through the heat engine.

[0059] 14. A specific heat energy can be supplied to the existing heat output, which corresponds to at least 90% of the isentropic enthalpy gradient of the heat engine, multiplied by the respective efficiency at the mass flow rate. The portion to which this specific heat energy cannot be supplied is routed via the bypass and expanded there.

[0060] If sufficient heat output is available in the heat exchanger, but, for example, the fluid mass flow rate is insufficient to completely dissipate the available heat energy, the heat exchanger is designed to transfer the heat to a thermal storage unit for buffering and / or to incorporate a bypass in the heat exchanger unit to reduce the amount of heat transferred from the heat source to the heat exchanger unit. This can also be achieved, for example, by adjusting the mass flow rate of the heat exchanger fluid, e.g., using a modulating pump.

[0061] Alternatively or additionally, the control device is further designed and configured to direct the mass flow of the fluid completely via the bypass when there is no or insufficient heat energy in the heat exchanger unit.

[0062] The advantages of the invention can be derived in particular from the following example: The fluid is water vapor (saturated steam), the nominal mass flow rate is 7.2 t / h, and it is expanded in the heat engine, which is designed as a turbine, from a pressure of 11 bar (absolute) to 3.5 bar (absolute). The efficiency of the turbine is 70%.

[0063] The transfer of 328 kW of heat (specifically 164 kJ / kg) via the heat exchanger unit leads to an increase in the inlet temperature of approximately 68.4 K. The heat engine extracts approximately 328 kW from the mass flow (isentropic enthalpy drop: 235 kJ / kg), so that the outlet temperature P45660PC00 / V / V ​​29.11.2025

[0064] The temperature at 15°C is approximately 161°C. The ratio of the specific heat energy to the isentropic enthalpy gradient yields the isentropic efficiency of the turbine (164 kJ / kg / 235 kJ / kg = 70%). With a generator efficiency of approximately 90%, 295 kW of electrical energy can be generated here.

[0065] If only 80% of the heat energy, i.e., approximately 263 kW, were transferred to the specified mass flow, a reduced temperature of approximately 147°C would result at the heat engine outlet. If 120% of the heat energy, i.e., approximately 394 kW, were transferred to the specified mass flow, an outlet temperature (target temperature) of approximately 175°C would result.

[0066] In a partial load case, where for example less mass flow is available, less specific heat energy would be transferred to the mass flow, or if the heat output of the heat exchanger unit were lower, the mass flow routed through the turbine would be reduced and part of the mass flow would be routed via a bypass, for example.

[0067] For the turbine previously described for the nominal load case (100% case), the following parameters would result with otherwise identical boundary conditions and a mass flow reduced to 4.9 t / h:

[0068] The isentropic turbine efficiency was reduced to 44.4% with the turbine control selected here as an example. The part-load performance could be improved with a different turbine control. This would result in a fluid superheat of only 39.6 K with a heat energy input of 135 kW (specific 98 kJ / kg) and a heat energy output of 135 kJ / kg (isentropic enthalpy drop 222 kJ / kg). The lower enthalpy drop results from the reduced superheat. According to the invention, the turbine outlet temperature remains at 161 °C. The ratio of these two values ​​yields the isentropic efficiency (98 kJ / kg / 222 kJ / kg = 44.4%). P45660PC00 / V / V ​​29.11.2025

[0069] 16

[0070] One embodiment of the system provides that the heat energy is supplied via the heat exchanger unit upstream of the heat engine, in particular immediately before the inlet of the heat engine, and / or that the heat energy is supplied via the heat exchanger unit downstream of the heat engine, in particular immediately at the outlet of the heat engine. For this purpose, the heat exchanger unit comprises at least one heat exchanger arranged upstream of the heat engine, in particular immediately before the inlet of the heat engine, and / or at least one heat exchanger arranged downstream of the heat engine, in particular immediately at the outlet of the heat engine.It is also specifically provided that the heat exchanger upstream of the heat engine and / or the heat exchanger downstream of the heat engine has a heat exchanger bypass by means of which the existing mass flow can be diverted around the respective heat exchanger.

[0071] If, for example, the fluid flow downstream of the heat engine is to be available for another process with certain parameters, the heat energy extracted from the mass flow by the heat engine can be supplied to the mass flow upstream of the heat engine, downstream of the heat engine, or partly upstream and partly downstream.

[0072] In a system that has a bypass with a pressure relief device parallel to the turbine, it is provided that the heat energy can only be supplied to the mass flow via the heat exchanger unit downstream of a branch for the bypass. Then, only the portion of the mass flow that passes through the heat engine receives heat energy via the heat exchanger unit. However, it is also specifically provided that heat energy can be supplied to the mass flow via the heat exchanger unit upstream of a branch for the bypass. In this case, a water injection device is preferably arranged in the bypass to cool the portion of the mass flow passing through the bypass so that its parameters essentially correspond to the proportion of the P45660PC00 / V / V ​​29.11.2025

[0073] 17

[0074] The mass flow corresponds to that which has been routed through the heat engine. Preferably, the portion of the mass flow routed via the bypass is cooled to such an extent that the temperature reached is the same as that which would be reached with isenthalpic throttling, or that a desired target temperature is set, which is preferably in the range of ± 50 K, particularly ± 35 K, preferably ± 25 K, and most preferably ± 10 K, relative to the reference temperature that would be reached with isenthalpic throttling. The water injection device increases the mass flow of the fluid downstream of the heat engine.

[0075] Alternatively or additionally, a water injection device is provided for immediately downstream of the heat engine, particularly upstream of a bypass branch. This water injection device is intended for situations where a large amount of thermal energy is available in the heat exchanger unit, but the mass flow rate of the fluid upstream of the heat engine is relatively too low to dissipate this thermal energy and to provide the fluid downstream of the heat engine with predetermined parameters regarding pressure and temperature. In this case, the superheated fluid downstream of the heat engine is cooled by the water injection device, and the mass flow rate is simultaneously increased.

[0076] Particularly preferred, especially in embodiments where a water injection device is provided as described above, is a further development of the system designed for use with steam, particularly water vapor, as the fluid. The fluid is therefore steam, preferably water vapor. It is advantageous if the steam is present as saturated steam upstream and / or downstream of the heat engine.

[0077] It is further preferably provided that a control device and a bypass for the heat engine are provided, and that the control device is designed and configured such that only the portion of the mass flow via the P45660PC00 / V / V ​​29.11.2025

[0078] 18

[0079] A heat engine is used, which can be heated to a predetermined minimum temperature using the current heat output of the heat exchanger unit.

[0080] Another embodiment of the system provides that the heat exchanger unit is connected to a heat storage unit. In this embodiment, the heat storage unit serves as the heat source for the secondary heat and / or as a buffer for existing waste heat that cannot be transferred to the mass flow of the fluid at a given time. The heat storage unit is designed, for example, as described above, such as a solid-state heat storage unit containing rock, slag, concrete, rock salt, sand, or ceramics, or as a stratified storage unit or latent heat storage unit. For example, the heat storage unit may contain a melt, particularly a metal melt. The heat storage unit is integrated as part of the system according to the invention. Using a heat storage unit for buffering allows for further optimization of the heat utilization from the secondary heat source.

[0081] Preferably, the heat storage unit is designed to be heated with electricity. In particular, it is designed to be coupled to at least one renewable energy source, e.g., a photovoltaic system and / or a wind turbine and / or a hydroelectric power plant, so that the heat storage unit can be heated at least partially with the electricity from the renewable energy source. The heat from the heat storage unit can then be converted into electricity at any time using the system according to the invention.

[0082] Another embodiment of the system provides that the heat engine is designed to reduce the pressure of the fluid from between 8 bar and 40 bar to between 1 bar and 10 bar. Preferably, the mass flow rate of the fluid, in particular steam, is between 0.5 t / h and 25 t / h. P45660PC00 / V / V ​​29.11.2025

[0083] 19

[0084] The heat engine is designed for a fluid inlet temperature between 80°C and 300°C and / or an outlet temperature between 10°C and 250°C. For example, the fluid inlet temperature to the heat engine is between 10°C and 300°C and / or the outlet temperature is between 10°C and 250°C. For example, the fluid temperature before heat energy transfer through the heat exchanger unit is between 10°C and 250°C. Preferably, the fluid outlet temperature is above 100°C.

[0085] For the system according to the invention, heat engines with a maximum output of 2 MW, and in particular with a maximum output of 1 MW, have proven advantageous. Heat engines in this power range are especially suitable for use in waste heat recovery. The efficiency of the heat engine at nominal mass flow is preferably in the range between 0.5 and 0.85.

[0086] The system according to the invention is advantageously suited for the use of heat sources in industrial plants. According to one embodiment, it has proven advantageous if the heat output of a secondary heat source connected to the heat exchanger unit is independent of the mass flow rate of the fluid. The heat output available in the heat exchanger unit is decoupled from the mass flow rate of the fluid. The heat output present in the heat exchanger unit is therefore preferably not drawn from the mass flow rate of the fluid. The heat output of the heat exchanger unit is particularly decoupled from the mass flow rate of the fluid. The heat source for the heat used is preferably decoupled and independent of the mass flow rate. The heat energy of the heat source is therefore available from a process that is independent of the availability and quantity of the mass flow rate of the fluid. P45660PC00 / V / V ​​29.11.2025

[0087] 20

[0088] The heat source for the primary or secondary heat is preferably a waste heat stream, an exhaust gas stream, or a hot air stream. The heat exchanger unit is designed to absorb the thermal energy from the secondary heat source and then transfer it back to the mass flow of the fluid. In particular, the heat source for the secondary heat is a volatile heat source, i.e., a heat source with fluctuating thermal output. Alternatively or additionally, the mass flow of the fluid is volatile, and in particular, the thermal output of the heat source is constant or also volatile.

[0089] Another embodiment of the system provides for a control device, designed and configured such that the mass flow is completely diverted to the heat engine via a bypass when the heat engine's power output falls below 1 kW. In the bypass, the mass flow is preferably depressurized to the same pressure that would be present downstream of the heat engine.

[0090] According to a further embodiment of the system, it is provided that the system has at least one control device, and that the control device can regulate at least the amount of heat transferred to the fluid by means of the heat exchanger unit, in particular the specific amount, and that by influencing the specific heat energy supplied to the mass flow of the fluid by means of the heat exchanger unit, it is possible to regulate whether the state of the fluid downstream of the heat engine essentially corresponds to that of an isenthalpic throttling without a heat engine or whether more or less heat energy is contained in the mass flow compared to an isenthalpic throttling.

[0091] Furthermore, it is preferably provided that, according to a design of the plant, the heat engine is designed such that the efficiency of the heat engine, in particular at nominal mass flow of the fluid, is essentially in proportion to the ratio of the P45660PC00 / V / V ​​29.11.2025 that can be supplied with the heat exchanger unit.

[0092] 21 specific enthalpy divided by the isentropic enthalpy gradient of the heat engine. Preferably, the efficiency of the heat engine is in the range between 0.5 and 0.85. Particularly preferably, the efficiency of the heat engine, especially at nominal mass flow, is in the range between 0.4 and 0.95.

[0093] A further embodiment of the system provides, in particular, that the specific heat energy supplied to the fluid via the heat exchanger unit is regulated, at least at nominal mass flow rates, such that the ratio of the supplied specific heat energy to the isentropic enthalpy gradient of the heat engine is less than 1, preferably less than 0.9, less than 0.8, or less than 0.7. Preferably, the ratio is greater than 0.3, particularly greater than 0.4, greater than 0.5, or greater than 0.6. The aforementioned values ​​can be combined. Preferably, this ratio corresponds essentially to the isentropic efficiency of the heat engine.

[0094] It is particularly preferred that the specific heat energy supplied to the fluid by means of the heat exchanger unit, especially at least at nominal mass flow rate, is regulated such that the aforementioned ratio corresponds to the isentropic efficiency of the heat engine.

[0095] The ratio q Z The ratio ugegeben / Ahis, where qzugegeben denotes the supplied specific heat energy and Ahis denotes the specific isentropic enthalpy gradient of the heat engine, can serve as a measure of the thermodynamic operation of the plant. If this ratio is less than 1, it means that the supplied specific heat energy is less than the theoretically maximum usable specific enthalpy gradient under isentropic expansion.

[0096] It is specifically intended that the control device is designed and configured to adjust the ratio depending on the available heat output of the heat exchanger unit, the current mass flow rate of the fluid and / or the P45660PC00 / V / V ​​29.11.2025

[0097] The control unit dynamically adjusts the desired target temperature downstream of the heat engine to 22. It can evaluate sensor data on temperature, power, pressure, and / or mass flow of the fluid at various points in the system.

[0098] The aforementioned problem is further solved by a method for operating a plant, for example, a plant according to one of the described embodiments. The plant comprises at least one heat engine and at least one heat exchanger unit. The heat engine can be supplied with a mass flow of a pressurized, non-flammable fluid. Thermal energy can be transferred to the mass flow by means of the heat exchanger unit. The method is characterized in that thermal energy is supplied to the mass flow of the fluid, particularly at nominal mass flow, by means of the heat exchanger unit, preferably directly upstream and / or downstream of the heat engine, in order to compensate for at least 80%, and in particular at least 90%, of the thermal energy extracted from the mass flow by the heat engine, and / or to set a target temperature of the mass flow of the fluid, particularly at nominal mass flow, downstream of the heat engine.

[0099] The mass flow of the fluid is supplied with at least 80% of its thermal energy, particularly at nominal mass flow rates, by means of a heat exchanger unit, especially at nominal mass flow rates, e.g., by means of at least one heat exchanger upstream and / or downstream of the heat engine. This thermal energy corresponds, particularly at nominal mass flow rates, approximately to the efficiency of the turbine at that mass flow rate, particularly nominal mass flow rate, multiplied by the isentropic enthalpy gradient of the heat engine.

[0100] If the heat energy removed from the mass flow by the heat engine is essentially compensated, the P45660PC00 / V / V ​​29.11.2025

[0101] 23

[0102] The heat engine produces a fluid mass flow temperature that is approximately the same as that obtained by isenthalpic throttling of the fluid mass flow to the same pressure. If the thermal energy in the mass flow is only compensated to about 80% or about 90%, the temperature downstream of the heat engine will be lower than would result from isenthalpic throttling. If the thermal energy is compensated to about 110% or about 120%, the temperature downstream of the heat engine will be higher than would result from isenthalpic throttling.

[0103] Preferably, according to one embodiment of the method, the supply of heat energy is carried out in such a way that the heat energy extracted by means of the heat engine is compensated so that a target temperature is established downstream of the heat engine which would be in the range of ± 50 K, in particular ± 35 K, preferably ± 25 K, particularly preferably ± 10 K with reference to a reference temperature of an isenthalpic throttling.

[0104] If the fluid is itself a carrier of significant thermal energy, such as water vapor, this method can be used to balance the utilization of two heat flows through the heat engine. A further development of the method specifically provides that, depending on a target temperature of the fluid at the heat engine outlet, heat transfer from the heat exchanger unit to the mass flow of the fluid controls whether the thermal energy extracted from the mass flow originates from the primary heat already present in the mass flow before heat is supplied via the heat exchanger unit, and / or whether the thermal energy extracted from the mass flow by the heat engine originates from the secondary heat supplied to the mass flow via the heat exchanger unit.

[0105] For example, the temperature, which during your isenthalpic throttling, can also have the same pressure as downstream of the heat engine P45660PC00 / V / V ​​29.11.2025

[0106] The temperature set to 24 is used as the reference temperature. If the temperature of the fluid mass flow at the outlet corresponds to the reference temperature, the heat energy extracted from the mass flow by the heat engine is approximately equal to the heat energy supplied to the mass flow by the heat exchanger unit. If the temperature is below the reference temperature, both primary and secondary heat are extracted by the heat engine. If the temperature is above the reference temperature, the extracted heat energy originates only from secondary heat, and some secondary heat remains in the mass flow. Preferably, the target temperature downstream of the heat engine is in the range of ± 50 K, particularly ± 35 K, preferably ± 25 K, and most preferably ± 10 K relative to the reference temperature that would result from isenthalpic throttling.

[0107] One embodiment of the method provides that the mass flow of the fluid in the system is diverted such that, depending on the heat output of the heat exchanger unit, only a portion of the mass flow is directed through the heat engine, where the heat energy extracted by the heat engine can be compensated by at least 80%, preferably at least 90%, and particularly preferably at least 100%. The remaining portion of the mass flow of the fluid is preferably routed via the bypass.

[0108] For details of the construction and operation of the plant with which the process is carried out, reference is also made to the description of the individual embodiments of the plant, which apply equally to the process.

[0109] The aforementioned problem is further solved by using a mass flow of pressurized steam to generate kinetic energy, in particular electrical energy, using heat from a heat source. The mass flow rate used is P45660PC00 / V / V ​​29.11.2025

[0110] 25. The fluid is expanded at least partially via a heat engine, in particular with an attached driven machine, wherein the heat energy extracted from the mass flow in the heat engine is essentially introduced into the mass flow expanded via the heat engine by means of a heat exchanger unit. The heat engine is preferably designed such that the isentropic enthalpy gradient of the heat engine at nominal mass flow, multiplied by the efficiency of the heat engine at nominal mass flow of the fluid, corresponds approximately to the continuous heat output that can be transferred from the heat exchanger unit to the fluid at nominal mass flow. The heat engine is therefore preferably designed based on the available secondary heat, e.g., waste heat or heat from a heat storage device.

[0111] It is specifically intended that preference be given to use with a system possessing some or all of the characteristics of a described system and / or with a process possessing some or all of the characteristics of a described process. In this respect, reference is made to the respective description of the system and / or process.

[0112] The aforementioned problem is also solved with the aspects of the invention described below:

[0113] A system for utilizing heat from a heat source, comprising at least one heat engine, in particular at least one driven machine, at least one control device, at least one bypass, and at least one heat exchanger unit, wherein the heat engine and the bypass can be supplied with a mass flow of a pressurized fluid, wherein the bypass is arranged parallel to the heat engine, wherein the bypass is designed for the expansion of the fluid, and wherein thermal energy, in particular from a heat source, can be transferred to the mass flow of the fluid by means of the heat exchanger unit, characterized in that the control device is designed and configured such that the proportion of the heat flow via the heat engine P45660PC00 / V / V ​​29.11.2025

[0114] 26 and / or the bypass-guided mass flow of the fluid is controllable at least as a function of the current heat output of the heat exchanger unit.

[0115] Particularly when the heat exchanger unit is coupled to a heat source with volatile thermal output, it has proven advantageous for the proportion of the mass flow that passes through the heat engine to be determined by the thermal output available in the heat exchanger unit. If a thermal output is available that can supply the entire mass flow with thermal energy corresponding to at least 80%, and in particular at least 90%, of the enthalpy drop of the heat engine, multiplied by the efficiency of the heat engine at that mass flow rate, then the entire mass flow is heated and passed through the heat engine, or passed through the heat engine and then reheated.

[0116] If the heat output is lower, only the portion of the mass flow that can be sufficiently heated as described above is directed through the heat engine; the remaining portion is routed via the bypass and expanded there to the same pressure. In such an operating mode, it is advantageous if the heat energy supplied to the portion of the mass flow routed through the heat engine is approximately equal to the amount of heat energy that is subsequently extracted from the heat engine as described above.

[0117] A further aspect of the invention relates to a method for designing a heat engine, in particular a turbine, a system for utilizing thermal energy, wherein a mass flow of a pressurized, preferably non-flammable, fluid is expanded to a target pressure in the system, and wherein thermal energy can be supplied to the mass flow by means of a heat exchanger unit, characterized in that at least the following method step is included: Designing the heat engine such that the efficiency of the heat engine at the nominal mass flow rate of the fluid essentially corresponds to the ratio of the specific enthalpy that can be supplied by the heat exchanger unit divided by the isentropic enthalpy gradient of the heat engine. P45660PC00 / V / V ​​29.11.2025

[0118] 27

[0119] The nominal mass flow rate of the fluid is selected, for example, on the basis of a maximum, in particular specific, continuous heat output of the heat exchanger unit or the heat source of the heat exchanger unit.

[0120] The maximum continuous heat output, for example of a volatile heat source, relative to heat availability, describes the thermal output that can be considered reliably available over the majority of the operating time (e.g., at least 70% or at least 90% of the operating time). The maximum continuous heat output is understood as a conservative figure based on statistical analyses (e.g., average availability over time) or empirical data. It allows for reliable planning of heat sinks, heat storage systems, or downstream processes.

[0121] The nominal mass flow rate is determined, for example, during the system design based on the maximum, and in particular specific, continuous heat output of the heat source or heat exchanger unit, or it may be a given nominal mass flow rate in an industrial plant. The heat engine is then designed based on the maximum continuous heat output of the heat source or heat exchanger unit.

[0122] It is particularly preferred that the heat engine dimensioned according to the aforementioned method is used in a system according to the invention or operated according to one of the described methods. In particular, it is possible to control, via the specific heat energy supplied by the heat exchanger device, especially with the control device, whether the specific heat energy extracted by the heat engine is drawn from the heat exchanger unit and thus from the heat source.

[0123] secondary heat source or from the primary mass flow of the fluid, i.e., in this consideration of the primary heat source. P45660PC00 / V / V ​​29.11.2025

[0124] 28

[0125] The various configurations of this system are derived from the exemplary embodiments of the described system.

[0126] Another aspect concerns a heat utilization system comprising at least one heat engine and at least one heat exchanger unit, wherein the heat engine can be supplied with a pressurized, non-flammable fluid to expand the fluid, and wherein thermal energy can be transferred to the fluid via the heat exchanger unit. Such a system is characterized in that the heat engine is designed to have an efficiency whose value corresponds to the ratio of the specific heat energy supplied by the heat exchanger unit to the specific isentropic enthalpy drop of the heat engine. The supply of specific heat via the heat exchanger unit is regulated such that the value, particularly at least at nominal mass flow, is less than 1.Preferably, the heat exchanger unit is designed such that a specific heat energy can be supplied to the fluid, in particular at least at nominal mass flow rate, which is at least 80% of the isentropic enthalpy gradient of the heat engine multiplied by the efficiency of the heat engine at nominal mass flow rate.

[0127] Such a system can be designed with the described features of a system, for which reference is made to the description. In particular, dependent claims with the features of dependent claims 2 to 12 can be subordinated to such a system.

[0128] Another aspect of the invention relates to a method for operating a plant for utilizing heat, in particular according to one of the described embodiments, comprising at least one heat engine and at least one heat exchanger unit, wherein the heat engine is supplied with a mass flow of a pressurized, non-flammable fluid P45660PC00 / V / V ​​29.11.2025

[0129] 29 is subject to pressure, and wherein heat energy can be transferred to the mass flow of the fluid using the heat exchanger unit.

[0130] The procedure is characterized by the fact that it includes at least the following procedural step:

[0131] - Supply of heat energy to the mass flow of the fluid by means of the heat exchanger unit, wherein the supply of heat energy to the mass flow of the fluid, particularly at nominal mass flow, is controlled such that the ratio between the supplied specific heat energy and the isentropic enthalpy gradient of the heat engine is less than 1, and in particular that the ratio is greater than 0.3. Preferably, the ratio is less than 0.9, less than 0.8, or less than 0.7. For example, the ratio is greater than 0.3, greater than 0.4, greater than 0.5, or greater than 0.6. The aforementioned limits can be combined. Particularly preferably, the specific heat energy supplied to the fluid by means of the heat exchanger unit, particularly at least at nominal mass flow, is controlled such that the ratio essentially corresponds to the isentropic efficiency of the heat engine.

[0132] The described procedures are carried out at least at nominal mass flow rate, or rather, the stated conditions must be met at least at nominal mass flow rate. However, it is also intended that the system be controlled in such a way that the stated conditions are met even under other load conditions, particularly under any partial load conditions. Specifically, it is intended that, during the implementation of the procedure, and especially during the control of the system, the heat output of the heat transfer unit is adjusted, e.g., by means of a bypass and / or heat storage and / or modulation of pumps, etc., and / or that a portion of the fluid mass flow is routed via a bypass, and / or that the efficiency of the heat engine is adjusted, e.g., by changing the rotational speed, etc.

[0133] The aforementioned procedure can be further developed and enhanced using the features of the described procedures. For this purpose, reference is made to the associated description P45660PC00 / V / V ​​29.11.2025.

[0134] Reference is made to paragraph 30. In particular, the features of claims 14 to 17 can be subordinated to this method.

[0135] Further advantageous embodiments of the invention will become apparent from the following description of the figures and the dependent subclaims.

[0136] They show:

[0137] Fig. 1 shows a schematic representation of an exemplary embodiment of a system,

[0138] Fig. 2 shows another embodiment of a system in schematic representation,

[0139] Fig. 3 shows another embodiment of a system in schematic representation,

[0140] Fig. 4 shows another embodiment of a system in schematic representation,

[0141] Fig. 5 shows an exemplary embodiment of a method in schematic representation.

[0142] In the various figures of the drawing, identical parts are always labelled with the same reference symbols.

[0143] The following description claims that the invention is not limited to the exemplary embodiments and not to all or several features of the described combinations of features; rather, each individual partial feature of the exemplary embodiment(s) is also significant for the subject matter of the invention, independent of all other partial features described in connection therewith, both on its own and in combination with any features of another exemplary embodiment. P45660PC00 / V / V ​​29.11.2025

[0144] 31

[0145] Fig. 1 shows a schematic embodiment of a system 1. The system 1 for utilizing secondary heat from a heat source 3b comprises at least one heat engine 2, at least one heat exchanger unit 3, and at least one control device 4. The heat engine 2 is designed as a turbine and can be supplied with a pressurized, non-combustible fluid, here steam, to expand the fluid and drive a working machine 5, here a generator. Thermal energy can be transferred to the fluid via the heat exchanger unit 3. The thermal energy is absorbed by the heat exchanger unit 3 from a heat source 3b, for example, by thermal oil circulating in an exhaust gas within a heat exchanger and being transferred, by means of a heat exchanger 3a arranged upstream of the heat engine 2, to the portion of the fluid mass flow that passes through the heat engine 2.The components of plant 1 are connected to each other via pipelines 6. A branch 6a for a bypass 7, which is arranged parallel to the heat engine 2, is located upstream of the heat exchanger 3a. The bypass 7 is designed to throttle the mass flow of the fluid. For example, the bypass 7 has at least one reducing valve.

[0146] The control device 4 has, in particular, shut-off and / or control valves to influence, for example, the branch 6a and thus the flow path of the fluid or parts thereof. Furthermore, the control device 4 is designed and configured to influence the heat exchanger unit 3 in order to affect its heat output, the heat absorption at the heat source 3b, and / or, for example, the buffering of heat in a heat storage unit 3d (see Fig. 2).

[0147] The heat exchanger unit 3 is designed and dimensioned such that, at least at nominal mass flow rate, the fluid can be supplied with heat energy that is at least 80%, and in particular at least 90%, of the isentropic enthalpy drop of the heat engine multiplied by the efficiency of the heat engine at nominal mass flow rate. (P45660PC00 / V / V ​​29.11.2025)

[0148] 32

[0149] The dimensioning of the heat exchanger unit 3 preferably takes into account the parameters of the heat source whose heat is to be utilized, in particular its continuous heat output and / or availability. It is preferably provided that sensible heat is supplied via the heat exchanger unit 3.

[0150] In an alternative embodiment, the heat source 3b is provided for to be a heat storage medium, in particular a latent heat storage medium, in particular a molten metal storage medium, or a sensible heat storage medium, e.g. sand or rock.

[0151] Fig. 2 shows a further embodiment of a system 1 in schematic representation. The system 1 for utilizing heat from a heat source 3b comprises at least one heat engine 2, at least one heat exchanger unit 3, and at least one control device 4. The heat engine 2 is designed here as a turbine and can be supplied with a pressurized, non-flammable fluid, here steam, to expand the fluid and to drive a working machine 5, here a generator. Thermal energy can be transferred to the fluid via the heat exchanger unit 3.The heat energy is absorbed by the heat exchanger unit 3 in a heat source 3b, for example by a thermal oil circulating in a heat exchanger in an exhaust gas and being transferred by means of a first heat exchanger 3a, which is arranged upstream of the heat engine 2 and a second heat exchanger 3c, which is arranged downstream of the heat engine 2, to the part of the mass flow of the fluid that is passed over the heat engine 2.

[0152] The components of system 1 are connected to each other via pipelines 6. A branch 6a for a bypass 7, which is arranged parallel to the heat engine 2, is located upstream of the first heat exchanger 3a. The bypass 7 is designed to throttle the mass flow of the fluid. A second branch 6b to the bypass 7 is located between the first heat exchanger 3a and the P45660PC00 / V / V ​​29.11.2025

[0153] 33

[0154] Heat engine 2 is arranged. With the second branch 6b, a portion of the mass flow of the fluid heated by means of the first heat exchanger 3a can be routed via the bypass 7 and expanded there as required.

[0155] To reduce the temperature of the mass flow in the bypass, a water injection device 8 is arranged in bypass 7. Injecting water via the water injection device 8 increases the mass flow in bypass 7. The portion of the fluid mass flow from bypass 7 is then recombined downstream of the second heat exchanger 3c with the portion of the mass flow that passes through the heat engine 2.

[0156] Optionally, the heat exchanger unit 3 includes a heat storage unit 3d, here in the form of a solid-state storage unit, which can be supplied with heat from the heat source 3b if the mass flow rate of the fluid is insufficient to dissipate the heat output present in the heat exchanger unit 3. The thermal energy stored in the heat storage unit 3d can be transferred to the mass flow of the fluid at a later time. This further optimizes heat utilization.

[0157] The control device 4 has, in particular, flow and throughput control elements to influence, for example, the branch 6a and the branch 6b and thus the flow path of the fluid or parts thereof. Furthermore, the control device 4 is designed and configured to influence the heat exchanger unit 3 in order to affect its heat output, the heat absorption at the heat source 3b and / or the buffering of heat in the heat storage unit 3d.

[0158] Fig. 3 shows a further embodiment of plant 1 in schematic representation. Plant 1 is constructed similarly to the embodiment of Fig. 1, with the difference that the heat exchanger unit has only one heat exchanger 3b directly behind the heat engine 2. P45660PC00 / V / V ​​29.11.2025

[0159] 34

[0160] The system 1 comprises at least one heat engine 2, at least one heat exchanger unit 3, and at least one control device 4. The heat engine 2 is designed as a turbine and can be pressurized with a non-flammable fluid, in this case nitrogen, to expand the fluid and drive a working machine 5, in this case a generator. The nitrogen originates, for example, from a pressure swing adsorption (PSA) plant located upstream of the system 1. Thermal energy can be transferred to the fluid via the heat exchanger unit 3. The thermal energy is absorbed by the heat exchanger unit 3 in a heat source 3b, which in this case is designed as a heat storage device. Thermal energy is transferred to the portion of the fluid mass flow that has passed through the heat engine 2 by means of a heat exchanger 3b located downstream of the heat engine 2.

[0161] The components of plant 1 are interconnected via pipelines 6. A branch 6a for the bypass 7, which is arranged parallel to the heat engine 2, is located upstream of the heat exchanger 3a. The bypass 7 is designed to throttle the mass flow of the fluid.

[0162] Fig. 4 shows a further embodiment of a system 1 in schematic representation. The system 1 for utilizing heat from a heat source 3b comprises at least one heat engine 2, at least one heat exchanger unit 3, and at least one control device 4. The heat engine 2 is designed here as a turbine and can be supplied with a pressurized, non-combustible fluid, here steam, to expand the fluid and to drive a working machine 5, here a generator. Thermal energy can be transferred to the fluid via the heat exchanger unit 3. The thermal energy is absorbed by the heat exchanger unit 3 in a heat source 3b, for example, by thermal oil circulating in an exhaust gas within a heat exchanger and being transferred to the mass flow of the fluid by means of a first heat exchanger 3a, which is arranged upstream of the heat engine 2. P45660PC00 / V / V ​​29.11.2025

[0163] 35

[0164] Since the heat exchanger 3a is arranged upstream of the branch 6a for a bypass 7 in this embodiment, the mass flow heated by the heat exchanger 3a can be greater than the nominal mass flow that is subsequently routed through the heat engine 2. However, the same specific heat energy is then supplied to the mass flow as described above. The heat energy supplied to the portion routed through the heat engine 2, for example, a nominal mass flow, is extracted again by the heat engine 2. Another portion is routed from the branch 6a through the bypass 7 and cooled there by a water injection device 8 to the same temperature as the mass flow at the outlet of the heat engine 2.

[0165] The components of plant 1 are connected to each other via pipelines 6. The branch 6a for a bypass 7, which is arranged parallel to the heat engine 2, is located downstream of the heat exchanger 3a. The bypass 7 is designed to throttle the mass flow of the fluid.

[0166] All the systems 1 shown in Figures 1 to 4 are preferably operated such that a specific heat energy is supplied to the mass flow passing through the heat engine 2, corresponding to the specific heat energy resulting from the isentropic enthalpy gradient of the heat engine 2 multiplied by the efficiency of the heat engine 2 at the respective mass flow rate. In other words, the specific heat energy supplied to the mass flow is essentially exactly what is extracted from the mass flow by the heat engine 2.

[0167] Fig. 5 shows an embodiment of a method 100 for operating a plant, for example according to an embodiment of Figs. 1 to 4. The plant 1 has at least one heat engine 2 and at least one heat exchanger unit 3, wherein the heat engine 2 can be supplied with a mass flow of a pressurized, non-flammable fluid. P45660PC00 / V / V ​​29.11.2025

[0168] 36. With the heat exchanger unit 2, thermal energy can be transferred to the mass flow. The method 100 comprises at least the step of supplying thermal energy 101 to the mass flow of the fluid, for example at nominal mass flow, in an amount sufficient to compensate for at least 80% of the heat extracted from the mass flow by means of the heat engine 2 102 and / or to adjust a target temperature of the mass flow downstream of the heat engine 2, in particular at the outlet of the heat engine 2 or at an outlet of a heat exchanger 3b downstream of the heat engine 2 103. Preferably, adjustment 103 is achieved by compensating less thermal energy 102 or by overcompensating, i.e., by supplying more thermal energy than is removed by the heat engine 2.The temperature is set primarily by influencing the heat transfer via the heat exchanger unit 3, particularly by means of a control device 4. Setting a target temperature is necessary, for example, when the fluid downstream of the heat engine 2 must be supplied with specific parameters regarding pressure and / or temperature for a further process. If the heat energy 2 extracted by the heat engine 2 is compensated for by the supply of heat energy via the heat exchanger unit 3, a temperature is automatically established that essentially corresponds to the temperature that would result from isenthalpic throttling of the fluid to the same pressure.

[0169] Preferably, the mass flow 104 in the system is diverted, for example using the control device 4, such that, depending on the heat output of the heat exchanger unit 3, which is dependent, for example, on the heat output of the heat source 3b, only a portion of the fluid mass flow is directed through the heat engine 2, such that the heat energy extracted by the heat engine 2 can be compensated by the supply of heat energy via the heat exchanger unit 3 to at least 80%, preferably at least 90%, and particularly preferably 100%. The mass flow through the heat engine is thus regulated, in particular by means of the control device, e.g. using the P45660PC00 / V / V ​​29.11.2025

[0170] 37

[0171] Branch 6a according to Fig. 1, the remaining portion of the mass flow, which cannot be heated sufficiently to compensate for the extracted heat energy by at least 80%, preferably at least 90%, and particularly preferably at least 100%, is routed via the bypass 7. This occurs, for example, when the heat exchanger unit 3 or the heat source 3b temporarily lacks sufficient heat output.

[0172] The invention is not limited to the embodiments illustrated and described, but also encompasses all embodiments that have the same effect within the meaning of the invention. It is expressly emphasized that the embodiments are not limited to all features in combination; rather, each individual feature can also have inventive significance independently of all other features. Furthermore, the invention is not yet limited to the combination of features defined in claim 1, but can also be defined by any other combination of specific features from all disclosed individual features. This means that, in principle, virtually any individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application.

Claims

1. P45660PC00 / V / V ​​29.11.2025 38 Claims 1. Plant (1) for the utilization of heat, comprising at least one heat engine (2) and at least one heat exchanger unit (3), wherein the heat engine (2) can be supplied with a pressurized, non-flammable fluid in order to expand the fluid, and wherein heat energy can be transferred to the fluid by means of the heat exchanger unit (3), characterized in that the heat exchanger unit (3) is designed such that, at least at nominal mass flow rate of the fluid, a specific heat energy can be supplied to the fluid by means of the heat exchanger unit (3) which is at least 80% of the isentropic enthalpy gradient of the heat engine (2) multiplied by the efficiency of the heat engine (2) at nominal mass flow rate.

2. Plant (1 ) according to claim 1 , characterized in that the heat energy can be supplied upstream of the heat engine (2) by means of the heat exchanger unit (3) and / or that the heat energy can be supplied downstream of the heat engine (2) by means of the heat exchanger unit (3).

3. Plant (1 ) according to claim 1 or 2, characterized in that the plant (1 ) is designed for use with steam, in particular water vapor, as the fluid, or that the plant (1 ) is designed for use with nitrogen or oxygen as the fluid. P45660PC00 / V / V ​​29.11.2025 39 4. Plant (1) according to one of claims 1 to 3, characterized in that the supply of heat energy by means of the heat exchanger unit (3) is controllable such that the portion of the mass flow directed over the heat engine (2) is supplied with essentially the specific heat energy which is extracted again from the portion of the mass flow directed over the heat engine (2) and / or that the supply of specific heat energy to the mass flow by means of the heat exchanger unit (3) takes place depending on a predetermined target temperature of the portion of the mass flow directed over the heat engine (2) downstream of the heat engine (2).

5. Plant (1 ) according to one of claims 1 to 4, characterized in that at least one bypass (7) for the fluid is arranged parallel to the heat engine (2), in particular that at least one water injection device (8) is arranged in the bypass (7), and / or in particular that at least one water injection device (9) is arranged downstream of the heat engine (2), preferably before a branch to the bypass (7).

6. System (1 ) according to one of claims 1 to 5, characterized in that the heat exchanger unit (3) is connected to at least one heat storage unit (3b, 3d), in particular that the heat storage unit (3b) is the heat source and / or that the heat storage unit (3d) is a buffer storage unit for intermediate storage of heat from a heat source (3b). P45660PC00 / V / V ​​29.11.2025 40 7. Plant (1) according to one of claims 1 to 6, characterized in that the heat engine (2) and / or a bypass (7) is designed for pressure reduction of the fluid from a pressure in the range between 8 bar and 40 bar to a pressure between 1 bar and 10 bar and / or that the heat engine (2) has a maximum power output of 2 MW, in particular of 1 MW and / or that the heat engine (2) is designed for an inlet temperature of the fluid between 10°C and 300°C and / or that the heat engine (2) is designed for an outlet temperature between 10°C and 250°C.

8. System (1 ) according to one of claims 1 to 7, characterized in that a heat output of a heat source connected to the heat exchanger unit (3) is independent of the mass flow of the fluid and / or that the heat output of a heat source connected to the heat exchanger unit (3) is volatile.

9. Plant (1) according to one of claims 1 to 8, characterized in that at least one control device (4) and a bypass (7) are provided in parallel to the heat engine (2), and that the control device (4) is designed and configured such that the proportion of the mass flow of the fluid directed via the heat engine (2) and / or the bypass (7) is controllable at least as a function of a heat output of the heat exchanger unit (3), in particular that the mass flow of the fluid is directed completely via the bypass (7) when the power of the heat engine (2) falls below 1 kW. P45660PC00 / V / V ​​29.11.2025 41 10. Plant (1) according to one of claims 1 to 9, characterized in that the plant has at least one control device, and that the control device can control at least the amount of heat transferred to the fluid by means of the heat exchanger unit, in particular the specific amount, and that by influencing the specific heat energy supplied to the mass flow of the fluid by means of the heat exchanger unit (3) it is possible to control whether the state of the fluid downstream of the heat engine (2) essentially corresponds to that of an isenthalpic throttling without a heat engine (2) or whether more or less heat energy is contained in the mass flow compared to an isenthalpic throttling.

11. Plant (1) according to one of claims 1 to 10, characterized in that the heat engine (2) is designed such that the efficiency of the heat engine (2) at nominal mass flow rate of the fluid essentially corresponds to the ratio of the specific enthalpy that can be supplied with the heat exchanger unit (3) divided by the isentropic enthalpy gradient of the heat engine (2), preferably that the efficiency of the heat engine (2) at nominal mass flow rate is in the range between 0.5 and 0.

85.

12. Plant (1) according to one of claims 1 to 10, characterized in that the specific heat energy supplied to the fluid by means of the heat exchanger unit (3), in particular at least at nominal mass flow rate, is regulated such that the ratio of the supplied specific heat energy to the isentropic enthalpy gradient of the heat engine (2) is less than 1, in particular that the ratio is greater than 0.3, in particular preferably the specific heat energy supplied to the fluid by means of the heat exchanger unit (3), in particular at least at nominal mass flow rate, is regulated such that P45660PC00 / V / V ​​29.11.2025 42 will be that the ratio corresponds to the isentropic efficiency of the heat engine (2).

13. Method (1) for operating a plant (1) for utilizing heat, in particular according to one of claims 1 to 12, comprising at least one heat engine (2) and at least one heat exchanger unit (3), wherein the heat engine (2) can be supplied with a mass flow of a pressurized, non-flammable fluid, and wherein heat energy can be transferred to the mass flow of the fluid by means of the heat exchanger unit (3), characterized in that at least the following process step is included: - Supplying (101 ) of heat energy to the mass flow of the fluid by means of the heat exchanger unit (3) in order to compensate for at least 80% of the heat energy removed from the mass flow by means of the heat engine (2) and / or to set a target temperature of the mass flow of the fluid downstream of the heat engine (2) (102).

14. Method according to claim 13, characterized in that the supply (101) is carried out in such a way that the heat energy extracted from the mass flow by means of the heat engine (2) is substantially compensated (101) or that the supply (101) of heat energy is carried out in such a way that the heat energy extracted by means of the heat engine (2) is compensated so that a target temperature is established downstream of the heat engine which would be in the range of ± 50 K, in particular ± 35 K, preferably ± 25 K, particularly preferably ± 10 K, with reference to a reference temperature of an isenthalpic throttling. P45660PC00 / V / V ​​29.11.2025 43 15. Method according to claim 13 or 14, characterized in that it further comprises at least the following method step: - Diverting (104) the mass flow in the system (1) such that, depending on the heat output of the heat exchanger unit (3), only a portion of the mass flow is directed through the heat engine (2), in which the specific heat energy extracted by the heat engine (2) can be compensated to at least 80%, preferably at least 90%, particularly preferably 100%, in particular wherein the remaining portion of the mass flow of the fluid is directed through the bypass (7).

16. Method according to one of claims 13 to 15, characterized in that, depending on a target temperature of the fluid at the outlet of the heat engine (2), it is controlled by heat transfer from the heat exchanger unit (3) to the mass flow of the fluid whether the heat energy extracted from the mass flow originates from the primary heat that the mass flow passing over the heat engine (2) already comprised before the supply of heat by means of the heat exchanger unit (3) and / or whether the heat energy extracted from the mass flow by the heat engine (3) originates from the secondary heat that is supplied to the mass flow by means of the heat exchanger unit (3).

17. Method according to one of claims 13 to 15, characterized in that the supply (101) of heat energy to the mass flow of the fluid by means of the heat exchanger unit (3), in particular at nominal mass flow, is regulated such that the ratio between the specific heat energy supplied by means of the heat exchanger unit (3) and the isentropic enthalpy gradient of the heat engine (2) is essentially P45660PC00 / V / V ​​29.11.2025 44 efficiency of the heat engine (2) corresponds, in particular where the efficiency is between 0.4 and 0.

95.

18. Use of a mass flow of pressurized steam to generate kinetic energy using heat from a heat source, wherein the mass flow of the fluid is expanded at least partially via a heat engine (2), and wherein at least in the portion of the mass flow of the fluid expanded via the heat engine (2) substantially the specific heat energy from a heat source is introduced by means of a heat exchanger unit (3) which is extracted from the mass flow of the fluid in the heat engine (2).

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