Method and assembly for using cooling potentials for generating electric energy using an orc circuit process

Abstract

The invention relates to a method and an assembly for using cooling potentials for generating electric energy using an ORC circuit process, in particular in the presence of a heat sink, the temperature gradient of which is substantially higher than the temperature gradient of a heat source. The aim of the invention is therefore to overcome the disadvantages of the prior art and provide an energy generating method which reduces energy losses during the generating process and which maximizes system efficiency. Additionally, the aim of the invention is to provide an assembly for carrying out the method. This is achieved by the features specified in the claims.

Description

Method and arrangement for using cooling potentials to generate electrical energy by means of an ORC cycle Description

[0001] The present invention relates to a method and an arrangement for utilizing cooling potentials to generate electrical energy by means of an ORC cycle, in particular in the presence of a heat sink whose temperature gradient is significantly higher than the temperature gradient of a heat source.

[0002] The Organic Rankine Cycle (ORC) is a clockwise cycle used to generate electricity from low-temperature heat.

[0003] It represents a process for operating steam turbines that is not driven by steam, but by an alternative working fluid that has more favorable evaporation properties at lower temperatures and pressures than water. Organic liquids such as isobutane, ethanol, or toluene are used.

[0004] This process is used when the available temperature gradient between the heat source and sink is too low to operate a steam-driven turbine. This is the case, for example, in power generation using geothermal energy, combined heat and power (CHP), and ocean thermal power plants.

[0005] The ORC is therefore a process that consists of at least two circuits. In the first circuit, the pressurized and liquid working fluid absorbs thermal energy from a heat source of choice via a heat exchanger and is evaporated. The resulting vapor expands in an expander and thus generates torque to drive a turbine to generate electricity using a generator coupled to the turbine. In the second circuit, the gaseous working fluid is evaporated in a condenser, a The heat exchanger, which uses the selected heat sink as a coolant, cools the fluid, thereby converting it to its liquid state. The liquid working fluid is then brought back to operating pressure by a pump and returned to the heat exchanger. The process begins again.

[0006] The integration of additional internal circuits is possible. For example, the expanded steam can be fed into a third heat exchanger, a so-called regenerator, before condensation and thus used for internal heat recovery for the evaporation process, thereby increasing electrical efficiency.

[0007] The working fluid used during an ORC process can be in pure form or in the form of a mixture of substances.

[0008] When a pure substance is used as a working medium, the phase change, the transition between the liquid and gaseous states, occurs isothermally, i.e. at a constant temperature.

[0009] When a mixture of substances is used as a working medium, so-called zeotropic mixtures are used. These are mixtures whose components have different boiling points. As a result, the phase transition is not isothermal, unlike with pure substances. A so-called temperature glide occurs during condensation and evaporation, the magnitude of which depends on the mixture composition.

[0010] The mixture composition can be adjusted during the ORC process, whereby a distinction is made between continuous and discontinuous systems for adjustment.

[0011] In discontinuous systems, the composition is the same throughout the system. When the operating situation changes, the composition is adjusted by separating and storing a portion of the working fluid. The change in composition therefore only occurs at specific points in time, i.e., discontinuously. The goal here is to adapt the cycle to changes in operating conditions.

[0012] In continuous systems, different compositions prevail at different points in the system. The composition is continuously adjusted. The goal is to optimize the cycle, for example, by more effectively utilizing the heat source and sink (reducing exergetic losses during heat transfer) or achieving more favorable pressure conditions.

[0013] The change in composition is achieved either by means of a separator (passive system) or by means of a rectification column (active system).

[0014] The problem can be represented in a temperature-entropy diagram (Ts diagram), where the specific cycle work corresponds to the area enclosed by the ORC cycle. To achieve maximum power yield, this area should be as large as possible. The area between the heat source and sink not occupied by the ORC cycle corresponds to the exergy losses.

[0015] The aim of the cycle design is therefore to fill the area between heat source and sink in the Ts diagram as completely as possible.

[0016] If a heat sink is present for the ORC process whose temperature gradient is significantly higher than the temperature gradient of the heat source, this ideally corresponds to a right-angled triangle in the Ts diagram, with the hypotenuse being the heat sink.

[0017] An example of the existence of such boundary conditions is the supercritical evaporation of liquefied natural gas (hereinafter LNG) with seawater as the heat source. Other examples of heat sources and sinks with comparable behavior are latent heat sources (heat transfer with phase change, e.g., during the condensation of water vapor), the supercritical evaporation of heat sinks, and the combination of several heat sinks on different temperature levels in series connection (e.g. simultaneous low-temperature heating and hot water requirements).

[0018] For this purpose, the state of the art describes different system circuits.

[0019] US 2013 / 0 174 551 A1 discloses an organic Rankine cycle power generation system utilizing a highly fluidized working fluid. In particular, this disclosure relates to a system that separates components of a working fluid to improve the effectiveness of a condenser, improve the thermal efficiency of the system, and reduce condenser costs compared to those required for unseparated flow.

[0020] WO 2005 / 031 123 A1 discloses a closed-loop device for generating electricity from a low-temperature heat source.

[0021] CN 1 03 306 764 A discloses a Kalina recirculation system with a two-phase expansion machine comprising a heating device, a separation device, expansion machines, a generation device, an absorption and cooling device and an amplification device.

[0022] KIM, Kyeongsu [et al.]: Design and optimization of cascade organic Rankine cycle for recovering cryogenic energy from liquefied natural gas using binary working fluid. In: Energy: the international journal, Vol. 88, 2015, pp. 304-313. - ISSN 0360-5442 (P); 1873-6785 (E). DOI: 10.1016 / j.energy.2O15.05.047. URL https: / / www.sciencedirect.com / science / article / pii / S0360544215006283 / pdf ft?md5=6aa7d1 dceOfOfe3bOd21550065a1 df20&pid=1 -s2.0- S0360544215006283-main.pdf [accessed on 2023-10-13] use a zeotropic mixture for an ORC cycle with LNG as a heat sink. The disadvantage here is the technical complexity, since these The publication includes a cascade of three ORC circuits. This entails comparatively high investment costs. At the same time, a high working fluid volume is expected, which also represents a high cost factor.

[0023] COLLINGS, Peter ; YU, Zhibin ; WANG, Enhua: A dynamic organic Rankine cycle using a zeotropic mixture as the working fluid with composition tuning to match changing ambient conditions. In: Applied Energy, Vol. 171, 2016, pp. 581-591. - ISSN 0306-2619(P); 1872-9118(E). DOI: 10.1016 / j.apenergy.2O16.03.014. URL https: / / www.sciencedirect.com / science / article / pii / S0306261916303257 / pdf ft?md5=c6f2db0864cbc6300fed9afbbf36e00e&pid=1- s2.0S0306261916303257-main.pdf [accessed on 2023-10-17] pursue the task of dynamically adjusting the composition of the working fluid in response to seasonally fluctuating conditions of the heat sink, in this case air. They describe an active, discontinuous adjustment of the working fluid, whereby the column is not directly integrated into the ORC cycle but is housed in a separate control loop.As a result of the rectification, the two mixture components of the working fluid can be stored separately and fed to the ORC process as required, whereby a joint evaporation of the components takes place.

[0024] Publications CN 2 06 233 960 U and CN 2 06 707 782 U disclose the development of a simplified method for adjusting the composition of the working fluid using a modified condenser (liquid separation condenser). They describe a passive, discontinuous adjustment of the working fluid. The disadvantage of this method is that the partial mass flow with a higher proportion of the volatile component is fed directly into the second condenser without further expansion beforehand, so that a significant portion of the exergy remains unused.

[0025] CN 2 09 875 221 II discloses a system for reducing exergy losses during the ORC process, which involves passive, continuous adjustment of the working fluid. The more volatile mixture component is not used for power generation after separation by the separator.

[0026] CN 1 02 797 525 A discloses a system configuration in which a passive, continuous adjustment of the working fluid occurs. After separation by the separator, the more volatile mixture component is directed to the expansion machine and then mixed with the saturated liquid flowing out of the separator.

[0027] CN 1 09 611 169 A discloses a system circuit which is intended to allow independent adjustment of the mixture composition on the high and low pressure sides to adapt to fluctuations in the heat source and sink.

[0028] ASTOLFI, Marco [et al.]: Cryogenic ORC to enhance the efficiency of LNG regasification terminals. In: Energy Procedia, Vol. 129, 2017, pp. 42-49. - ISSN 1876-6102. DOI: 10.1016 / j.egypro.2017.09.177. URL: https: / / www.sciencedirect.com / science / article / pii / S1876610217340912 / pdf ?md5=a73deObad65f42d9e314c7f57c2671a4&pid=1-s2.0- S1876610217340912mxain.pdf [accessed on 2023-10-17] describe an ORC process with LNG as the heat sink. Here, the working fluid is separated into a liquid and a vapor phase after passing through a first turbine stage. Part of the vapor phase is then expanded again in a second turbine stage and subsequently condensed. The two-stage condensation allows for better adaptation of the ORC cycle to the temperature gradient of the LNG, thus reducing exergy losses.However, this arrangement requires the working fluid to expand into the wet steam, which leads to material-related stresses on the turbine (risk of droplet erosion). Furthermore, a pure substance is used as the working fluid, which influences the temperature profile of the ORC cycle during operation. Condensation is not adapted to the temperature profile of the heat sink as well as with a zeotropic mixture and higher exergy losses occur in comparison. Description of the invention

[0029] The object of the invention is to eliminate the disadvantages of the prior art and to provide a method for energy generation that reduces exergy losses during energy generation and maximizes plant efficiency. Furthermore, the object of the invention is to provide an arrangement for implementing the method.

[0030] This problem is solved by the features listed in the claims.

[0031] The object is achieved by a method for energy generation by means of an ORC cycle, which has a heat sink and a heat source, wherein the following process steps are carried out: a) Heat removal from a working fluid x on the heat sink side, wherein the working fluid x is a zeotropic mixture and has at least two mixture components with different boiling points. The working fluid x is present with a mixture composition xM. The heat removal on the heat sink side takes place by means of a condenser KM. After passing through the condenser KM, the working fluid x is present as wet steam. b) Separation of the working fluid x with the mixture composition xM by means of at least one separation device T. Here, the mixture composition xM is changed into a first partial stream A and a second partial stream B. The first partial stream A has a partial stream composition xA, and the second partial stream B has a partial stream composition xB, where xA * xM * xB. c) Expanding the first partial stream A by means of a first partial stream expander EA2 and then condensing the first partial stream A by means of a second condenser KA. d) Increasing the pressure of the two partial streams A and B by means of pumps PA and PB. e) Evaporating the liquefied and separated partial streams A and B on the heat source side in evaporators VA and VB. f) Expanding the partial streams A and B by means of at least one expander EM. Subsequently, the partial streams A and B are fed back to the condenser KM and the process is carried out again from process step a).

[0032] Substream A contains a larger proportion of a more volatile mixture component (with a lower boiling point) of the working fluid x. Substream B contains a larger proportion of a less volatile mixture component (with a higher boiling point) of the working fluid x.

[0033] According to various embodiments, after carrying out process step b), the second partial stream B is present as a liquid phase and / or the first partial stream A is present as a gaseous phase.

[0034] According to various embodiments, after carrying out process step c), the first partial stream A is present as a liquid phase.

[0035] According to various embodiments, liquefied natural gas and / or liquefied hydrogen is used as the heat sink. Other heat sinks are conceivable. Furthermore, a combination of several heat sinks at different temperature levels in series connection is conceivable, for example, a simultaneous low-temperature heating and hot water requirement. Also conceivable is the Use of supercritical heat sinks, e.g. regasification of liquefied hydrogen (LH2) for injection into a pipeline.

[0036] According to various embodiments, seawater and / or ground heat and / or outside air are used as the heat source. Other heat sources are conceivable. For example, waste heat from agricultural and / or industrial processes, e.g., a biogas plant, can be used. Appropriately tempered exhaust gases, e.g., from lime and cement kilns, can also be used as a heat source. Furthermore, solar thermal energy can be utilized. Latent heat sources, i.e., heat transfer from the source with phase changes, e.g., during the condensation of water vapor, can also be utilized.

[0037] According to various embodiments, the at least one separation device T comprises at least one separator and / or a rectification column.

[0038] According to various embodiments, the first partial flow expander EA2 and / or the expander EM are designed as a turbine, which drives a generator to generate electricity. Other configurations of the expansion machine(s) are conceivable, for example, in the form of a screw expander and / or a steam engine / reciprocating piston expander.

[0039] The object is further achieved by an arrangement for energy generation, wherein the arrangement comprises a heat sink, a heat source and an ORC circuit. The ORC circuit comprises a working fluid x, which is a zeotropic mixture and has at least two mixture components with different boiling points. The working fluid x is present with a mixture composition xM. Furthermore, the ORC circuit comprises a condenser KM arranged on the heat sink side and at least one separating device T for separating the working fluid x into at least a first partial stream A with the composition xA and a second partial stream B with the Composition xB. Furthermore, the ORC cycle has a first partial flow expander EA2 and a second condenser KA for condensing partial flow A and two pumps PA and PB for increasing the pressure of the two partial flows A and B. In addition, the ORC cycle has two evaporators VA and VB arranged on the heat source side for evaporating partial flows A and B and at least one expander EM for expanding partial flows A and B.

[0040] According to various embodiments, the heat sink is a reservoir of liquefied natural gas or liquefied hydrogen. Other heat sinks are conceivable. A combination of several heat sinks at different temperature levels in series is also conceivable, for example, to meet simultaneous low-temperature heating and hot water requirements. The use of supercritical heat sinks is also conceivable, e.g., the regasification of liquefied hydrogen (LH2) for feeding into a pipeline.

[0041] According to various embodiments, the heat source is a reservoir of seawater and / or the ground and / or outside air. Other heat sources are conceivable. For example, waste heat from agricultural and / or industrial processes, e.g., a biogas plant, can be used. Appropriately tempered exhaust gases, e.g., from lime and cement kilns, can also be used as a heat source. Furthermore, solar thermal energy can be utilized. Latent heat sources, i.e., heat transfer from the source with phase changes, e.g., during condensation of water vapor, can also be utilized.

[0042] According to various embodiments, the at least one separation device T comprises at least one separator and / or a rectification column.

[0043] According to various embodiments, at least one of the expanders EA2 / EM is designed as a turbine, which drives a generator to generate electricity. Other embodiments of the Expansion machine(s) are conceivable, for example in the form of a screw expander and / or steam engine / reciprocating piston expander.

[0044] When considering a plant based on the Carnot process (pure substance as the working medium with isothermal phase change), the Ts diagram shows that optimal results cannot be achieved with this process in relation to the task.

[0045] The use of zeotropic mixtures (non-isothermal phase change) as the working fluid in an ORC process appears advantageous in that the cycle can be better adapted to the temperature gradients (difference between inlet and outlet temperatures) of the heat source and sink than with a pure substance. This leads to reduced exergy losses and thus to higher cycle efficiency. However, even in such a cycle (e.g., the Lorenz cycle), significant exergy losses occur, although adjusting the composition of the working fluid can minimize these losses.

[0046] The method and arrangement according to the invention enable efficient energy generation using an ORC cycle, particularly in the presence of a heat sink whose temperature gradient is significantly higher than the temperature gradient of a heat source. This minimizes exergy losses compared to conventional processes.

[0047] The basic concept here is to adjust the composition of the zeotropic working fluid within the system so that the temperature glide on the low-pressure side is as large as possible and that on the high-pressure side as small as possible. The change in the mixture composition is achieved using a separation device within the system. Another advantage of the process according to the invention is the two-stage expansion of partial stream A using the expander EA, allowing a larger portion of the theoretically usable exergy to be used for power generation. Implementation of the invention

[0048] The invention will be explained in more detail using one or more exemplary embodiments. Figure 1 shows an arrangement for energy generation, Figure 2 Alternative arrangement for energy generation.

[0049] In the description, reference is made to the accompanying drawings, which show, by way of illustration, specific embodiments in which the arrangement according to the invention may be practiced. In this regard, directional terminology such as "top," "bottom," etc., is used with reference to the orientation of the described drawings. The directional terminology is for illustrative purposes and is in no way limiting.

[0050] It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is understood that the features of the various exemplary embodiments described herein may be combined with one another unless specifically stated otherwise. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0051] In the figures, identical or similar elements are provided with identical reference numerals where appropriate.

[0052] Figure 1 shows an embodiment of the arrangement according to the invention for energy generation by means of an ORC cycle, particularly in the presence of a heat sink whose temperature gradient is significantly higher than the temperature gradient of a heat source. The arrangement comprises a heat sink, a heat source, and an ORC cycle. The ORC cycle comprises a working fluid x which is a zeotropic mixture and has at least two mixture components with different boiling points. The working fluid x is present with a mixture composition xM. Furthermore, the ORC circuit has a condenser KM arranged on the heat sink side and at least one separation device T for separating the working fluid x into at least a first partial stream A with the composition xA and a second partial stream B with the composition xB. Furthermore, the ORC circuit has a first partial stream expander EA2 and a second condenser KA for liquefying the partial stream A and two pumps PA and PB for increasing the pressure of the two partial streams A and B. In addition, the ORC circuit has two evaporators VA and VB arranged on the heat source side for evaporating the partial streams A and B and at least one expander EM for expanding the partial streams A and B.Here, the partial mass flows A and B are combined after the evaporators VA and VB and expanded together in an expander EM. The advantage of this variant is the elimination of one expander.

[0053] In the condenser KM, so much heat is removed from the working fluid with the mixture composition xM that the vapor mass fraction is significantly reduced. After leaving the condenser KM, the working fluid enters the separation device T as wet vapor and is split into saturated liquid with the composition xB and saturated vapor with the composition xA, where xA * xM * xB, in particular xA > xB. The saturated vapor with the composition xA is then expanded again in the first partial flow expander EA2 (if the separation device is a separator, the working fluid must not be completely condensed in the condenser KM, as otherwise no change in composition occurs. If, however, a column is used, complete condensation in KM is possible, so that liquid and not wet vapor as described can enter the separation device).The saturated steam with the mixture composition xA is then expanded again in the first partial flow expander EA2 and in the. Condenser KA condenses. The two mass flows, now in liquid form, with mixture compositions xA and xB, are then separately pressurized in pumps PA and PB, evaporated in evaporators VA and VB, and expanded in expander EM. The two partial mass flows are combined before or in expander EM, resulting in a total mass flow M of the working fluid x with mixture composition xM.

[0054] According to various embodiments, the heat sink is a reservoir of liquefied natural gas or liquefied hydrogen. Other heat sinks are conceivable. A combination of several heat sinks at different temperature levels in series is also conceivable, for example, to meet simultaneous low-temperature heating and hot water requirements. The use of supercritical heat sinks is also conceivable, e.g., the regasification of liquefied hydrogen (LH2) for feeding into a pipeline.

[0055] According to various embodiments, the heat source is a reservoir of seawater and / or the ground and / or outside air. Other heat sources are conceivable. For example, waste heat from agricultural and / or industrial processes, e.g., a biogas plant, can be used. Appropriately tempered exhaust gases, e.g., from lime and cement kilns, can also be used as a heat source. Furthermore, solar thermal energy can be utilized. Latent heat sources, i.e., heat transfer from the source with phase changes, e.g., during condensation of water vapor, can also be utilized.

[0056] According to various embodiments, the at least one separation device T comprises at least one separator and / or a rectification column. A realizable change in the mixture composition is significantly higher in a column than in a separator, however, during rectification heat must be added to the column, which leads to a loss in overall efficiency.

[0057] According to various embodiments, at least one of the expanders EA2 / EM is designed as a turbine that drives a generator to generate electricity. Other configurations of the expansion machine(s) are conceivable, for example, in the form of a screw expander and / or steam engine / reciprocating piston expander.

[0058] According to various embodiments, the expander EM of the energy generation arrangement comprises a second partial flow expander EA for expanding partial flow A and a third partial flow expander EB for expanding partial flow B. Figure 2 shows this alternative embodiment of the inventive arrangement for energy generation using an ORC cycle. Figure 2 shows a second partial flow expander EA and a third partial flow expander EB for separately expanding partial flows A and B. The partial flows A and B are recombined only after passing through the expanders, and then fed back into the condenser KM as working fluid x with the mixture composition xM. Reference symbol A first partial flow A of the working fluid B second partial flow B of the working fluid EA second partial flow expander for the first partial flow A EA2 first partial flow expander for the first partial flow A EB third partial flow expander for the second partial flow B EM Expander KA second capacitor KM capacitor M total mass flow of the working fluid PA pump partial flow A PB Pumpern Partial Flow B T separating device VA evaporator partial flow A VB Evaporator partial flow B x Working fluid xA Mixture composition of the first partial flow A xB Mixture composition of the second partial flow B xM Mixture composition of the total mass flow

Claims

Claims 1. A method for utilizing cold potentials to generate electrical energy by means of an ORC cycle comprising a heat sink and a heat source, comprising the following method steps: a) heat sink-side extraction of heat from a working fluid x, which is a zeotropic mixture comprising at least two mixture components with different boiling points and which has a mixture composition xM, wherein the heat sink-side extraction of heat takes place by means of a condenser KM, wherein the working fluid x is present as wet steam after passing through the condenser KM, b) separation of the working fluid x with the mixture composition xM by means of at least one separation device T, such that a change in the mixture composition xM takes place such that xM is separated into a first partial stream A with a partial stream composition xA and a second partial stream B with a partial stream composition xB, where xA * xM * xB,c) Expanding and subsequently condensing the first partial flow A by means of a first partial flow expander EA2 and a second condenser KA, d) Increasing the pressure of the two partial flows A and B by means of pumps PA and PB, e) Evaporating the separated partial flows A and B on the heat source side in the evaporators VA and VB, f) Expanding the partial flows A and B by means of at least one expander EM and then feeding them again to the condenser KM and repeating the process from process step a).

2. A process for utilizing cold potentials to generate electrical energy by means of an ORC cycle process according to claim 1, characterized in that after carrying out process step b) the second partial stream B is present as a liquid phase and / or the first partial stream A is present as a gaseous phase.

3. A process for utilizing cold potentials to generate electrical energy by means of an ORC cycle process according to claim 1, characterized in that after carrying out process step c) the first partial stream A is present as a liquid phase.

4. A method for utilizing cold potentials to generate electrical energy by means of an ORC cycle according to one of the preceding claims, characterized in that liquefied natural gas and / or liquefied hydrogen is used as the heat sink.

5. A method for utilizing cold potentials to generate electrical energy by means of an ORC cycle process according to one of the preceding claims, characterized in that seawater and / or heat from the earth and / or outside air and / or a heat source with latent heat transfer is used as the heat source.

6. A method for utilizing cooling potentials to generate electrical energy by means of an ORC cycle according to one of the preceding claims, characterized in that the at least one separation device T is at least one separator and / or a rectification column.

7. A method for utilizing cooling potentials to generate electrical energy by means of an ORC cycle according to one of the preceding claims, characterized in that the first partial flow expander EA2 and / or the expander EM are designed as a turbine which drives a generator to generate electricity.

8. Arrangement for utilizing cold potentials to generate electrical energy by means of an ORC cycle according to a method according to claim 1, wherein the arrangement comprises the following components: a heat sink and a heat source and an ORC cycle, wherein the ORC cycle has the following components: a working fluid x, wherein the working fluid x is a zeotropic mixture comprising at least two mixture components with different boiling points and which has a mixture composition xM, a condenser KM arranged on the heat sink side, at least one separation device T for separating the working fluid x into at least a first partial stream A with the composition xA and a second partial stream B with the composition xB, further comprising a first partial stream expander EA2 and a second condenser KA for liquefying the partial stream A, two pumps PA and PB for increasing the pressure of the two partial streams A and B,further comprising two evaporators VA and VB arranged on the heat source side for evaporating the partial streams A and B, at least one expander EM for expanding the partial streams A and B., 9. Arrangement for utilizing cold potentials to generate electrical energy by means of an ORC cycle according to claim 8, characterized in that the heat sink is a reservoir with liquefied natural gas or liquefied hydrogen.

10. Arrangement for utilizing cold potentials to generate electrical energy by means of an ORC cycle process according to claim 8 or 9, characterized in that the heat source is a reservoir with sea water and / or heat from the ground and / or outside air and / or a heat source with latent heat transfer.

11. Arrangement for utilizing cooling potentials to generate electrical energy by means of an ORC cycle process according to one of claims 8 to 10, characterized in that the at least one separation device T has at least one separator and / or a rectification column.

12. Arrangement for utilizing cooling potentials to generate electrical energy by means of an ORC cycle process according to one of claims 8 to 11, characterized in that at least one expander EA2 / EM is designed as a turbine which drives a generator to generate electricity.

13. Arrangement for utilizing cooling potentials to generate electrical energy by means of an ORC cycle process according to one of claims 8 to 12, characterized in that the expander EM has a second partial flow expander EA for expanding the partial flow A and a third partial flow expander EB for expanding the partial flow B.

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