DE102016112601A1 - Device for power generation according to the ORC principle, geothermal system with such a device and operating method - Google Patents

Abstract

The invention relates to a device for power generation according to the ORC principle with a heating medium circuit (10), a high-pressure ORC circuit (20) and at least one low-pressure ORC circuit (30), wherein the heating medium circuit (10) by a high-pressure Evaporator unit (21) and at least one high-pressure preheating unit (23) with the high-pressure ORC circuit (20) and by a low-pressure evaporator unit (31) and at least one low-pressure preheating unit (33) with the low-pressure ORC circuit (30 ) is thermally coupled, wherein in the Heizmittelkreislauf downstream of the high-pressure evaporator unit (21) branches off a Fernwärmevorlauf (12).

Description

The invention relates to a device for power generation according to the ORC principle according to the preamble of patent claim 1. Furthermore, the invention relates to a geothermal system with such a device and an operating method. A device of the type mentioned is, for example WO 2009/056341 A2 known.

Organic Rankine Cycle (ORC) energy generation devices are preferably used to utilize energy from low temperature heat sources. In this case, organic fluids which have a comparatively low boiling point are used as ORC fluids. Thus, the heat energy provided by the low-temperature heat source can be well utilized to generate, for example, electric power.

The aforementioned WO 2009/056341 A2 describes such a device for power generation, which operates on the ORC principle. The previously known device comprises two ORC circuits, which are thermally coupled together by a heating medium circuit. One of the ORC circuits serves as a high-pressure ORC circuit and has a high-pressure evaporator unit and a high-pressure preheating unit. Another ORC cycle forms a low pressure ORC cycle comprising a low pressure evaporator unit and at least one low pressure preheater unit.

Through the Heizmittelkreislauf flows a heating means, such as thermal water, which emits its heat energy successively via the high-pressure evaporator unit, the low-pressure evaporator unit and the high-pressure preheating unit and the low-pressure preheating unit to the working fluid in the two ORC circuits. In the ORC circuits, the working medium circulating there is heated, evaporated and directed to a respective turbine. In the turbine, the working fluid relaxes, generating mechanical energy, which is then converted into electrical energy by a generator connected to the turbine.

Although the efficiency of such a system is relatively high, it is still desirable to continue to use the heating means efficiently. For example, the thermal energy of the heating medium can be used directly as a heat medium, for example for a district heating network. In practice, the heat source two Heizmittelströme be removed, with a Heizmittelstrom to generate energy and another Heizmittelstrom be removed as a heat medium.

However, in power generating apparatuses operating in accordance with the ORC principle, the output temperatures of the heating means are usually comparatively low, so that it is expedient for the efficiency of the energy generation process to use the complete heating medium flow for power generation. However, the thermal energy available in the heating means is not used optimally, i. there remains a residual portion of still usable thermal energy.

The object of the invention is to improve a device for power generation according to the ORC principle so that the thermal energy of a heating means as well as possible and the efficiency of power generation is impaired as little as possible. It is another object of the invention to provide a geothermal plant with such an optimized device and an operating method.

According to the invention this object is achieved with regard to the device for generating energy by the subject-matter of claim 1, with regard to the geothermal system by the subject-matter of claim 13 and with regard to the method of operation by the subject-matter of claim 14.

Specifically, the invention is based on the idea to provide a device for generating energy according to the ORC principle with a heating medium circuit, a high-pressure ORC circuit and at least one low-pressure ORC circuit, wherein the heating medium circuit through a high-pressure evaporator unit and at least one high-pressure Preheating unit is thermally coupled to the high-pressure ORC cycle. The heating medium circuit is further thermally coupled to the low pressure ORC circuit by a low pressure evaporator unit and at least one low pressure preheater unit. In the heating medium circuit downstream of the high-pressure evaporator unit branches off a district heating advance.

By branching off the district heating advancement downstream of the high-pressure evaporator unit, it is ensured that at least the high-pressure evaporator unit is supplied with the complete mass flow of the heating medium flowing through the heating medium circuit. Consequently, a high amount of heat energy is provided for the vaporization of the ORC fluid in the high pressure ORC cycle.

It has been found that the ORC process can be operated efficiently despite the use of a partial flow of the heating means for the district heating by the inventive arrangement of the district heating advance. In concrete terms, the ORC process continues to have a relatively high mass flow of heating medium through the diversion of the district heating feed to the high-pressure evaporator unit Accordingly, a relatively high amount of heat available, which can be used for energy production. Thus, in a device for generating energy according to the ORC principle, a cogeneration can be efficiently implemented without significantly affecting the efficiency of energy generation.

In general, it is pointed out that the preheating units and / or evaporator units mentioned in the present application can have several components. In particular, the preheating units may each comprise a plurality of preheaters or heat exchangers, which together form a preheating unit. The same applies to the evaporator units mentioned in the application.

It is also conceivable that evaporator units and respectively associated preheating units form a common apparatus or are integrated in a common apparatus.

In a preferred embodiment of the device according to the invention, provision is made for the district heating feed to branch off in the direction of flow of the heating medium circuit immediately after the low-pressure evaporator unit. Specifically, it can be provided that the heating medium circuit is arranged so that the heating means is first supplied to the high-pressure evaporator unit and then the low-pressure evaporator unit. By branching off the district heating advance immediately after the low-pressure evaporator unit, it is further advantageously ensured that the complete mass flow of the heating means for heat transfer is also available to the low-pressure ORC cycle. Thus, the low pressure ORC cycle can be operated with high efficiency.

Another advantage of the present invention is that the provision of the complete Heizmittelmassestroms for at least the high-pressure evaporator unit, preferably also the low-pressure evaporator unit, leads to a reduction of the investment costs for such a power generating device. Specifically, at least the high-pressure evaporator unit, preferably also the low-pressure evaporator unit, can be equipped with a relatively small heat transfer area, since the complete mass flow of the heating medium is provided for heat transfer. A reduction in the mass flow, for example, by prior branching off the district heating advance, however, would require larger heat transfer surfaces to deliver the same amount of heat energy to the respective ORC fluid can.

In a further preferred embodiment of the invention, provision is made for the district heating feed to branch off between the low-pressure evaporator unit and the high-pressure preheating unit and / or the low-pressure preheating unit. The arrangement of the district heating advance at this point is particularly advantageous because on the one hand, the temperature of the heating medium at this point is still high enough to use it for a district heating supply. In particular, the heating medium can thus be fed into a low-temperature district heating network, i. The district heating feed can be connected to a low-temperature district heating network. On the other hand, the diversion of the Fernwärmevorlaufs between the low-pressure evaporator unit and the high-pressure preheating and / or the low-pressure preheating is advantageous because the reduction of the mass flow of the heating means for the subsequent preheating leads to no significant reduction in the amount of heat transferred.

The heating medium circuit may have a bifurcation in the flow direction after the district heating feed, which divides the heating medium circuit such that a heating medium flow of the heating medium cycle is proportionally supplied to the high-pressure preheating unit and the low-pressure preheating unit. In this way, the high-pressure preheating unit and the low-pressure preheating unit are supplied with heating means at the same temperature. This brings about improved efficiency, particularly in the low-pressure ORC cycle, since here the ORC fluid is conducted closer to the evaporation temperature. The overall efficiency of the device is thus improved.

In the preferred embodiment of the Heizmittelkreislaufs, after the low-pressure evaporator unit of the heating medium flow is divided into the high-pressure preheating and the low-pressure preheating, it is particularly advantageous if the district heating feed between the low-pressure evaporator unit and the fork branches off. In other words, a district heating medium substream is branched off before the remaining heating medium flow is split and the substreams are supplied to the high-pressure preheating unit and the low-pressure preheating unit.

The district heating supply can generally be connected to a district heating return. The district heating return preferably opens in the flow direction of the heating medium downstream of the district heating in the heating medium circuit. It is preferably provided that the district heating return in the flow direction of the heating medium circuit after the high-pressure preheating unit and / or after the low-pressure preheating unit opens into the heating medium circuit.

It is particularly preferred if in the flow direction of the heating medium circuit after the Low-pressure preheating a high-pressure Primärvorwärmeinheit in the high-pressure ORC circuit and / or a low-pressure Primärvorwärmeinheit in the low-pressure ORC circuit are arranged. These additional primary preheat units in the two ORC circuits use the remaining heat energy of the heating means particularly efficiently to preheat the ORC fluid in the ORC circuits. The heating medium is further cooled, so that a total of high heat utilization of the heating medium is ensured. Thus, the overall efficiency of the device can be further increased.

The high pressure preheating unit may be fluidly connected directly to the high pressure primary preheating unit. At the same time or alternatively, the low-pressure preheating unit may be fluidly connected directly to the low-pressure Primärvorwärmeinheit. In this way, it is ensured that the entire heating medium mass flow, which flows through the respective preheating unit, is also conducted to the respectively assigned primary preheating unit. In particular, it is provided that there is no diversion between the respective preheating unit and the respective primary preheating unit in that heating medium flow rate is taken from the heating medium circuit. This ensures that a relatively high mass flow flows through the Primärvorwärmeinheiten, whereby their heat transfer surfaces can be kept relatively small.

In order to achieve a further reduction of the heat transfer surfaces in the high-pressure Primärvorwärmeinheit and / or the low-pressure Primärvorwärmeinheit, it is particularly advantageous that the district heating return between the low-pressure preheating unit and the high-pressure Primärvorwärmeinheit and / or between the low-pressure preheating unit and the low pressure -Primärvorwärmeinheit opens into the heating medium circuit. In other words, the return flow from the district heating network upstream of the high-pressure Primärvorwärmeinheit and / or the low-pressure Primärvorwärmeinheit is fed back into the heating medium circuit. This increases the mass flow for the respective Primärvorwärmeinheit so that their heat transfer surfaces can be further reduced. In particular, in this way with a relatively small heat transfer surface sufficient heat energy can be transferred from the heating means to the respective ORC fluid.

If the source temperature of the heating medium is sufficiently high, it can preferably be provided that branches off in the flow direction of the Heizmittelkreislaufs before the high-pressure evaporator Fernwärmebypass, which is connected to the district heating return. Thus, before the supply of the heating medium in the ORC process, a partial flow of the heating medium is diverted and fed into the district heating network. The return flow of the district heating bypass is preferably via the district heating return.

The return of the diverted by the Fernwärmevorlauf mass flow of the heating medium from the district heating network on the district heating return in the heating medium circuit has the further advantage that in this way too high a cooling of the heating medium in the heating medium circuit is avoided. In that regard, the district heating return also serves as frost protection for the heating medium circuit.

If in the flow direction of the heating medium circuit to the district heating return at least one Primärvorwärmeinheit, for example, a high-pressure Primärvorwärmeinheit or a low-pressure Primärvorwärmeinheit follows, so is provided by the additional return from the district heating bypass for the respective Primärvorwärmeinheit available Heizmittel mass flow further. As a result, the heat transfer surfaces of the respective Primärvorwärmeinheit can be further reduced, resulting in cost savings.

A further increase in efficiency of the entire ORC process can be achieved if, as is preferred, an additional high-temperature preheating unit is arranged between the high-pressure evaporator unit and the low-pressure evaporator unit in the high-pressure ORC circuit. Thus, the ORC fluid in the high-pressure ORC cycle can be warmed up to the evaporation temperature by the high-temperature preheating unit. In this way, the high-temperature preheating unit can be adapted optimally in terms of energy and economy to the heat transfer between the heating medium and the ORC fluid. In the high-pressure ORC cycle, the high-temperature preheating unit is preferably arranged between the high-pressure preheating unit and the high-pressure evaporator unit. This arrangement of the high-temperature preheating is energetically advantageous because the high-temperature preheating unit so only the temperature difference between the preheating of the high-pressure preheating unit and the evaporation temperature to be reached must bridge.

With regard to the ORC circuits, in particular the high-pressure ORC circuit and the low-pressure ORC circuit, it is preferably provided in the present invention that these open into a common ORC circuit. In other words, the high-pressure ORC circuit and the low-pressure ORC circuit can be at least partially merged and thus form a common ORC circuit in sections.

The common ORC cycle may be a common feed pump and / or one common recuperator and / or a common preheating unit and / or a common capacitor unit. In this way, further costs can be reduced because the two ORC circuits share components of the device. It is particularly preferred if a common capacitor unit is provided for the high-pressure ORC circuit and the low-pressure ORC circuit.

In this context it is also pointed out that both the high-pressure ORC circuit and the low-pressure ORC circuit can each comprise a turbine. The turbines may each be coupled to a generator to generate electrical energy from the mechanical energy generated in the turbine. Alternatively, it is possible for the high pressure ORC cycle and the low pressure ORC cycle to each act on separate impellers of a common turbine, with the common turbine coupled to a single, common generator.

In a further preferred embodiment of the device according to the invention for power generation can be provided that branches off in the flow direction of the heating medium immediately after the high-pressure evaporator unit, in particular between the high-pressure evaporator unit and the additional high-temperature preheating, a Zumischleitung which is connected to the district heating. This ensures on the one hand that the complete mass flow of the heating medium, which is made available to the ORC process, is available to the high-pressure evaporator unit. On the other hand, in this way relatively hot heating means is branched off after the high-pressure evaporator unit and fed to the district heating feed. Thus, the temperature provided to the district heating network can be increased. This is particularly useful if it is to be feared that the temperature of the heating medium after passing through the high-pressure preheating unit and / or the low-pressure preheating unit is not sufficient to be used for the district heating network meaningful. In this way, a stream of heating medium which has a higher temperature can be admixed with the mass flow branched off after the low-pressure preheating unit in the district heating feed. This increases the total temperature in the district heating advance.

A subsidiary aspect of the present invention relates to a geothermal plant with a previously described device for power generation. The geothermal plant may in particular be connected to a geothermal hot water source, wherein the hot water source provides the heating means for the heating medium circuit.

Furthermore, in the context of the present application, a method for operating a device for generating energy according to the ORC principle is disclosed and claimed, the device having a heating medium circuit, a high-pressure ORC circuit and at least one low-pressure ORC circuit. The heating medium circuit is thermally coupled to the high pressure ORC circuit by a high pressure evaporator unit and at least one high pressure preheater unit and to the low pressure ORC circuit by a low pressure evaporator unit. In the method according to the invention it is provided that of a Heizmittelstrom the Heizmittelkreislaufs downstream of the high-pressure evaporator unit, in particular between the low-pressure evaporator unit and the high-pressure preheating unit, a partial flow diverted and fed into a district heating network or used to heat a district heating medium in a district heating network. In particular, additional heat transfer units can be provided, which transfer thermal energy of the heating medium into the district heating medium.

In connection with the device for generating energy mentioned in the beginning and constructive developments apply analogously to the claimed and described method. In particular, it can be provided that the device operated according to the claimed method is designed according to the above description.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying schematic drawings. Show:

1 a process diagram of a device according to the invention for power generation according to a preferred embodiment;

2 a process diagram of a device according to the invention for power generation according to a further preferred embodiment, wherein additional Primärvorwärmeinheiten are provided;

3 a process diagram of a device according to the invention for power generation according to a further preferred embodiment, wherein an additional district heating bypass is provided;

4 a process diagram of a device according to the invention for power generation according to a further preferred embodiment, wherein an additional admixing line is provided for the Fernwärmevorlauf;

5 a process diagram of a device according to the invention for power generation according to a further preferred embodiment, wherein the Primärvorwärmeinheiten in the ORC circuits each have a frost protection circuit; and

6 : A process diagram of a device according to the invention for generating energy according to a further preferred embodiment, wherein the high-pressure ORC circuit and the low-pressure ORC circuit have a common ORC circuit.

In the accompanying drawings, a device for power generation according to the ORC principle is shown schematically. In general, the device described here has a heating medium circuit 10 thermally using a high pressure ORC cycle 20 and a low pressure ORC cycle 30 is coupled. The high pressure ORC cycle 20 and the low pressure ORC cycle 30 are essentially similar in structure. To distinguish the individual components that the high pressure ORC cycle 20 and the low-pressure ORC circuit, the abbreviations "HD" for components of the high-pressure ORC circuit will be referred to hereafter 20 ( "HD ORC cycle 20 ") And" ND "for low pressure ORC circuit components 30 ( "ND-ORC cycle 30 ").

The HD ORC circuit 20 includes in particular a HD evaporator unit 21 and an HD preheating unit 23 , In the flow direction of the ORC fluid of the HD-ORC cycle is the HD preheating unit 23 the HD evaporator unit 21 upstream.

The ND ORC cycle 30 includes a LP evaporator unit 31 and a LP preheating unit 33 , In the flow direction of the ORC fluid of the ND-ORC circuit 30 is the LP preheating unit 33 the LP evaporator unit 31 upstream.

As can also be seen in the illustrated drawings, the HD-ORC cycle 20 a high temperature preheating unit 22 on that between the HD preheat unit 23 and the HD evaporator unit 21 in the HD ORC cycle 20 is arranged. The additional high-temperature preheating unit 22 Although in many cases advantageous, but can also be omitted.

The HD evaporator unit 21 , the ND evaporator unit 31 , the HD preheating unit 23 and the LP preheating unit 33 are also in the heating medium circuit 10 involved. Specifically, the HD evaporator unit 21 in the flow direction of the heating medium circuit 10 the LP evaporator unit 31 upstream. On the LP evaporator unit 31 follow the HD preheating unit 23 and the LP preheating unit 33 , The optional high-temperature preheating unit 22 of the HD-ORC cycle 20 is in the flow direction of the heating medium in the heating medium circuit between the HP evaporator unit 21 and LP evaporator unit 31 arranged.

For all embodiments also applies that of the heating medium circuit 10 a district heating advance 12 branches off, the district heating advance 12 in the flow direction of the heating means of the heating circuit 10 the HD evaporator unit 21 is subordinate. Specifically, it is provided in the embodiments shown here that the district heating advance 12 immediately after the LP evaporator unit 31 from the heating medium circuit 10 branches.

In the flow direction of the heating means of the heating medium circuit 10 follows the branched district heating advance 12 in the embodiments shown here, a fork 13 , The fork 13 divides the heating medium flow of the heating medium circuit 10 and leads proportionately part streams of the heating medium to the HD preheating unit 23 and the LP preheating unit 33 , After flowing through the HD preheating unit 23 and the LP preheating unit 33 the two partial flows are reunited. This is in the heating medium circuit 10 a collection point 17 provided, the HD preheating unit 23 and the LP preheating unit 33 is subordinate.

In the embodiments according to 1 - 5 It also provides that each of the two ORC circuits 20 . 30 is essentially self-sufficient. In contrast to this is in 6 an embodiment shown in which the HD-ORC cycle 20 and the ND ORC cycle 30 through a common ORC cycle 40 connected or in a common ORC cycle 40 lead. This will be discussed in detail later.

In the embodiments according to 1 - 5 In particular, it provides that the HD-ORC cycle 20 an HD turbine 25 in the flow direction of the ORC fluid of the HD evaporator unit 21 is subordinate. That's the HD turbine 25 leaving ORC fluid then enters an HD condenser 26 and is condensed out there. The resulting condensate is in an HD condensate collection tank 27 collected. The HD condensate collector 27 is the HD capacitor 26 arranged downstream in the flow direction of the ORC fluid.

From HD condensate collector 27 the ORC fluid becomes the HD preheat unit 23 pumped. This is indicated by the HD-ORC cycle 20 an HD feed pump 28 on top of the HD condensate collector 27 is immediately downstream.

In the 1 - 5 is also evident that the HD-ORC cycle 20 an HD turbine bypass 29 having a valve. The HD turbine bypass 29 allows the HD turbine 25 to get around. Analogously, the ND-ORC cycle also exhibits 30 an LP turbine bypass 39 on.

The ND ORC cycle 30 is essentially analogous to the HD-ORC cycle 20 built up. In particular, the ND-ORC cycle has 30 essentially the same components, but dimensioned accordingly for the low pressure operation. Only for the high temperature preheating unit 22 There are in the illustrated embodiments in the ND-ORC circuit 30 no analog component. However, it is possible in the ND-ORC cycle 30 to insert an additional preheater between the LP preheating unit and the LP evaporator unit in an analogous manner.

Specifically, the ND-ORC cycle includes 30 an LP turbine 35 , the ND evaporator unit 31 downstream in the flow direction of the ORC fluid. On the LP turbine 35 follows an ND capacitor 36 in which the ORC fluid condenses out and to an LP condensate collector 37 is directed. The LP condensate collector 37 is the ND capacitor 36 immediately downstream in the flow direction of the ORC fluid. The ND ORC cycle 30 also includes an LP feed pump 38 , which preferably directly to the LP condensate collection tank 37 is subordinate. The ND feed pump 38 is preferably in front of the LP preheating unit 33 arranged.

In general, it can be provided that each of the ORC circuits 20 . 30 having a recuperator. In this respect, the ORC fluid in the respective ORC cycle 20 . 30 between the respective turbine 25 . 35 and the respective capacitor 26 . 36 be passed through a recuperator. The recuperator is preferably in the respective ORC cycle 20 . 30 arranged that of the respective feed pump 28 . 38 pumped ORC fluid first preheated by the recuperator and then the respective preheating unit 23 . 33 is supplied.

With a view to the individual components of the ORC circuits 20 . 30 is to emphasize that as capacitors 26 . 36 both air condensers, as well as a water cooling can be provided, wherein the water cooling in the context of the present application is also referred to as a capacitor unit.

Incidentally, it is possible that the two ORC circuits 20 . 30 share individual components. In particular, a common condensate collection 44 be provided with both the HD-ORC circuit 20 , as well as with the ND-ORC cycle 30 connected is. Alternatively or additionally, it is also possible to use a common capacitor unit 43 be provided. It is also possible that the two ORC circuits 20 . 30 a common feed pump 41 include. Likewise, a common recuperator 42 be provided with both ORC circuits 20 . 30 is coupled.

In the 1 - 4 different embodiments of the invention are shown, particularly in the design of the heating medium circuit 10 differ. The HD ORC circuit 20 and the ND ORC cycle 30 are essentially identical. The embodiments according to 5 and 6 On the other hand, they differ in the design of the ORC circuits 20 . 30 of the embodiments according to 1 - 4 ,

1 shows an embodiment of the invention, in which the heating medium circuit 10 a district heating advance 12 downstream of the LP evaporator unit 31 arranged and this in the heating medium circuit 10 is immediately downstream.

The district heating advance 12 branches from the heating medium circuit 10 from. In particular, the Fernwärmevorlauf 12 between the LP evaporator unit 31 and the crotch 13 arranged. The district heating advance 12 performs a partial mass flow of the heating medium from the heating medium circuit 10 and diverts this partial mass flow to a district heating network. The district heating advance 12 is indirectly via the district heating network with a district heating return 14 connected after the HD preheat unit 23 and the LP preheating unit 33 , in particular to the collection point 17 , in the heating medium circuit 10 empties.

Through the district heating advance 12 On the one hand, a partial mass flow of the heating medium is supplied to the district heating network. On the other hand, the mass flow of the heating means, which for the HD preheating unit 23 and the LP preheating unit 33 is available, reduced. However, the remaining mass flow is sufficient to remove the ORC fluids in the HD-ORC cycle 20 and the ND-ORC circuit 30 to preheat sufficiently. To be in the HD ORC cycle 20 to achieve a preheating up to the evaporation temperature, is also the high-temperature preheating unit 22 intended.

In the embodiment according to 2 is additionally provided that the heating medium circuit 10 with primary preheating units 24 . 34 is coupled. The primary preheating units 24 . 34 are in the flow direction of the heating means the preheating 23 . 33 downstream.

In particular, in the HD-ORC cycle 20 an HD primary preheating unit 24 arranged in Flow direction of the ORC fluid of the HD preheating unit 23 is upstream. Similarly, the ND-ORC cycle 30 an LP primary preheating unit 34 upstream of the LP preheating unit in the flow direction of the ORC fluid.

The heating medium circuit 10 includes a compensation line 16 that the HD preheat unit 23 , the LP preheating unit 33 , the HD primary preheating unit 24 and the LP primary preheating unit 34 connects with each other. In the compensation line 16 the district heating return ends 14 , The over the district heating return 14 additionally provided heating medium mass flow increases in this way the mass flow of the heating medium through the Primärvorwärmeinheiten 24 . 34 flows.

Specifically, the heating medium in the heating medium circuit 10 first at the fork 13 divided into two sub-streams. The HD preheating unit 23 and the LP preheating unit 33 in each case a partial flow is supplied. The two partial flows are after the HD preheating unit 23 and the LP preheating unit 33 through the equalization line 16 at the same time a return flow from the district heating network via the district heating return 14 is mixed. This mixture of the two partial streams coming from the HD preheating unit 23 and the LP preheating unit 33 come, and the return from the district heating network on the district heating return 14 is in turn divided into two primary sub-streams, each of the Primärvorwärmeinheiten 24 . 34 be supplied.

In the flow direction of the heating means is the Primärvorwärmeinheiten 24 . 34 the collection point 17 downstream. The collection point 17 unites those from the primary preheating units 24 . 34 coming primary streams including the added mass flow from the district heating network and leads them together.

The embodiment according to 3 essentially builds on the embodiment according to 2 on. In addition, in the embodiment according to 3 provided that in the flow direction of the heating medium in the heating medium circuit 10 the HD evaporator unit 21 a district heating bypass 11 is upstream, which branches off a partial flow of the heating medium before being supplied to the ORC process described here to the district heating network. About the district heating bypass 11 So part of the original Heizmittelmassestroms is derived in the district heating network. The district heating bypass 11 is indirect via the district heating network with the district heating return 14 connected. At the same time is the district heating advance 12 indirectly via the district heating network with the district heating return 14 connected. The district heating return 14 thus unites all previously branched off for the district heating network sub-mass flows and mixes them via the compensation line 16 the primary part streams of the heating medium, the primary preheating units 24 . 34 be forwarded.

In 4 a further embodiment of the invention is shown, wherein the embodiment according to 2 forms the basis. In addition to the embodiment according to 2 is in the embodiment according to 4 provided that between the HD evaporator unit 21 and the high temperature preheating unit 22 a mixing line 15 branches, which with the district heating advance 12 connected is. So can a mass flow of the after HD evaporator unit 21 still relatively hot heating medium in the Fernwärmevorlauf 12 be substantially increased and thus substantially increase the temperature of the provided for the district heating network Heizmittel mass flow accordingly.

The embodiment according to 4 also goes to the embodiment according to 2 back. In particular, the heating medium circuit 10 is identical to the heating medium circuit 10 according to 2 built up.

The embodiment according to 5 differs from the embodiments described above, however, by the design of the ORC circuits 20 . 30 , In particular, both in the HD-ORC cycle 20 , as well as in the ND ORC cycle 30 each provided a frost protection circuit, which is a damage to the HD Primärvorwärmeinheit 24 or the ND primary preheating unit 34 should avoid. Such a frost protection circuit can, of course, be implemented in all embodiments of the invention.

Specifically is in the HD-ORC cycle 20 an antifreeze bypass 46 is provided, which branches in the flow direction of the ORC fluid after the HD Primärvorwärmeinheit and before the HD Primärvorwärmeinheit 24 back into the HD ORC cycle 20 empties. In antifreeze bypass 46 is an antifreeze pump 47 arranged for a corresponding circulation of the ORC fluid in the antifreeze bypass 46 serves.

A corresponding antifreeze bypass 46 indicates the ND-ORC cycle 30 on. At the same time the antifreeze bypass branches 46 in the flow direction of the ORC fluid after the LP preheating unit 33 and ends in the ND ORC cycle 30 in front of the LP primary preheating unit 34 , The antifreeze bypass 46 in the ND-ORC cycle 30 also has an antifreeze pump 47 for the circulation of the ORC fluid in the antifreeze bypass 46 serves.

The antifreeze bypass 46 causes a backwashing of the respective Primärvorwärmeinheit 24 . 34 preheated ORC fluids, thus avoiding through the Primärvorwärmeinheit 24 . 34 flowing heating medium is cooled to below freezing. In particular, the antifreeze bypass 46 , For example by means of a corresponding control of the antifreeze pump 47 , be set so that a predetermined minimum temperature of the heating medium is not exceeded. In this way, for example, a chemical precipitation in the heating means can be avoided.

In 6 an embodiment of the invention is shown in which the HD-ORC cycle 20 and the ND ORC cycle 30 with a common ORC cycle 40 are coupled. The use of a common ORC cycle 40 is possible for all embodiments of the invention and is based on 6 based on the embodiment according to 1 merely exemplified.

The common ORC cycle 40 has a common recuperator 42 , a common capacitor unit 43 , a common capacitor tank 44 and a common feed pump 41 on. The ORC fluids of the HD-ORC circuit 20 and the ND-ORC cycle 30 arrive after exiting the HD turbine 25 or LP turbine 35 together in the shared recuperator 42 , When passing through the common recuperator 42 the ORC fluid mixture preheats already condensed ORC fluid mixture. In other words, in the recuperator 42 The extracted from the turbines relaxed ORC fluid mixture extracted heat and fed to the condensed ORC fluid mixture.

After the heat release in the common recuperator 42 the ORC fluid mixture enters the common condenser unit 43 , which may include, for example, an air condenser or a water cooling. In the common capacitor unit 43 the ORC fluid mixture is condensed out and in the common condensate collection tank 44 collected. About the common feed pump 41 the condensed and collected ORC fluid mixture becomes the common recuperator 42 promoted and there by the heat transfer of ORC fluid mixture, which from the Turiben 25 . 35 taken, preheated. Subsequently, the ORC fluid mixture is divided and each of the HD preheating unit 23 and the LP preheating unit 33 fed. The ORC fluids now flow separately through the HD-ORC circuit 20 or the ND ORC circuit 30 and only become immediately before the common recuperator 42 reunited.

In the embodiment according to 6 can in HD ORC cycle 20 in addition an HD feed pump 28 be provided. The HD feed pump 28 is preferably immediately after the branch of the ND-ORC cycle 30 arranged. Through the HD feed pump 28 can in HD ORC cycle 20 another pressure than in the ND-ORC cycle 30 be set.

In general, in all embodiments, which is in the 1 - 6 are shown provided that the HD turbine 25 and the LP turbine 35 are coupled together via a gearbox. In particular, the HD turbine 25 and the LP turbine 35 each form wheels of a common turbine, the wheels are connected by a reduction gear with each other. The HD turbine 25 and the LP turbine 35 are with a common generator 45 coupled to those in the turbines 25 . 35 generated kinetic energy or mechanical energy converts into electrical energy. Alternatively, it is possible that both the HD-ORC cycle 20 , as well as the ND-ORC cycle 30 each separate turbines 25 . 35 have, each turbine 25 . 35 a separate generator 45 assigned.

In general, it applies to all exemplary embodiments that the following substance groups can be used as ORC fluids in one or both ORC circuits: silicone oils, fully and partially halogenated hydrocarbons (in particular partially fluorinated hydrocarbons), hydrocarbons (in particular alkanes, alkenes, alcohols). In particular, alkanes such as n-pentane, isopentane, neopentane, n-butane and isobutane can be used as the ORC fluid. It is also possible to use a substance mixture of the abovementioned substance groups as ORC fluid.

The device according to the invention or the geothermal plant according to the invention can also have equipment typical of the installation, such as fittings, measuring instruments, control circuits, a control or similar auxiliary components.

LIST OF REFERENCE NUMBERS

10

 heating medium

11

 district heating bypass

12

 District heating supply

13

 crotch

14

 District heating return

15

 admixing

16

 compensation line

17

 collection

20

 High-pressure ORC cycle

21

 High pressure evaporator unit

22

 High-temperature preheating

23

 High-pressure preheating

24

 High pressure Primärvorwärmeinheit

25

 High pressure turbine

26

 High-pressure condenser

27

 High-pressure condensate collection vessel

28

 High-pressure feed pump

29

 High pressure turbine bypass

30

 Low pressure ORC cycle

31

 Low pressure evaporator unit

33

 Low pressure preheating

34

 Low pressure Primärvorwärmeinheit

35

 Low pressure turbine

36

 Low pressure condenser

37

 Low pressure condensate tank

38

 Low-pressure feed pump

39

 Low pressure Turbinenbypas

40

 Common ORC cycle

41

 Common feed pump

42

 Common recuperator

43

 Common capacitor unit

44

 Common condensate collector

45

 generator

46

 Frost protection bypass

47

 Antifreeze pump

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2009/056341 A2 [0001, 0003]

Claims (15)

Device for generating energy according to the ORC principle with a heating medium circuit ( 10 ), a high-pressure ORC circuit ( 20 ) and at least one low pressure ORC cycle ( 30 ), wherein the heating medium circuit ( 10 ) by a high-pressure evaporator unit ( 21 ) and at least one high-pressure preheating unit ( 23 ) with the high-pressure ORC circuit ( 20 ) and by a low-pressure evaporator unit ( 31 ) and at least one low-pressure preheating unit ( 33 ) with the low-pressure ORC circuit ( 30 ) is thermally coupled, characterized in that in the Heizmittelkreislauf downstream of the high-pressure evaporator unit ( 21 ) a district heating forecast ( 12 ) branches off. Apparatus according to claim 1, characterized in that the district heating ( 12 ) in the flow direction of the heating medium circuit ( 10 ) immediately after the low pressure evaporator unit ( 31 ) branches off. Apparatus according to claim 1 or 2, characterized in that the district heating ( 12 ) between the low pressure evaporator unit ( 31 ) and the high-pressure preheating unit ( 23 ) and / or the low-pressure preheating unit ( 33 ) branches off. Device according to one of the preceding claims, characterized in that the heating medium circuit ( 10 ) in the flow direction after the Fernwärmevorlauf ( 12 ) a fork ( 13 ), which the heating medium circuit ( 10 ) so that a Heizmittelstrom the Heizmittelkreislaufs ( 10 ) in each case proportionally to the high-pressure preheating unit ( 23 ) and the low-pressure preheating unit ( 33 ) is supplied. Apparatus according to claim 4, characterized in that the district heating ( 12 ) between the low pressure evaporator unit ( 31 ) and the fork ( 13 ) branches off. Device according to one of the preceding claims, characterized in that the district heating feed ( 12 ) with a district heating return ( 14 ), which in the flow direction of the heating medium circuit ( 10 ) after the high-pressure preheating unit ( 23 ) and / or after the low-pressure preheating unit ( 33 ) in the heating medium circuit ( 10 ) opens. Apparatus according to claim 6, characterized in that in the flow direction of the heating medium circuit ( 10 ) after the low-pressure preheating unit ( 23 ) a high pressure primary preheating unit ( 24 ) in the high-pressure ORC circuit ( 20 ) and / or a low-pressure Primärvorwärmeinheit ( 34 ) in the low pressure ORC cycle ( 30 ), wherein the high-pressure preheating unit ( 23 ) with the high-pressure primary preheating unit ( 24 ) and / or the low-pressure preheating unit ( 33 ) with the low-pressure primary preheating unit ( 34 ) is each directly fluidly connected. Apparatus according to claim 6 or 7, characterized in that the district heating return ( 14 ) between the low-pressure preheating unit ( 33 ) and the high-pressure primary preheating unit ( 24 ) and / or between the low-pressure preheating unit ( 33 ) and the low-pressure primary preheating unit ( 34 ) in the heating medium circuit ( 10 ) opens. Device according to one of claims 6 to 8, characterized in that in the flow direction of the heating medium circuit ( 10 ) in front of the high-pressure evaporator ( 21 ) a district heating bypass ( 11 ), which is connected to the district heating return ( 14 ) connected is. Device according to one of the preceding claims, characterized in that between the high-pressure evaporator unit ( 21 ) and the low-pressure evaporator unit ( 31 ) in the high-pressure ORC circuit ( 20 ) an additional high-temperature preheating unit ( 22 ) is arranged. Device according to one of the preceding claims, characterized in that the high-pressure ORC circuit ( 20 ) and the low pressure ORC circuit ( 30 ) into a common ORC cycle ( 40 ), the common ORC cycle ( 40 ) a common feed pump ( 41 ) and / or a common recuperator ( 42 ) and / or a common preheating unit and / or a common capacitor unit ( 43 ) having. Device according to one of the preceding claims, characterized in that in the flow direction of the heating medium circuit ( 10 ) immediately after the high pressure evaporator unit ( 21 ), in particular between the high-pressure evaporator unit ( 21 ) and the additional high-temperature preheating unit ( 22 ), a mixing line ( 15 ), which is connected to the district heating 12 ) connected is. Geothermal plant with a device according to one of the preceding claims. Method for operating a device for generating energy according to the ORC principle, wherein the device - a heating medium circuit ( 10 ), - a high-pressure ORC circuit ( 20 ) and - at least one low pressure ORC cycle ( 30 ) and - the heating medium circuit ( 10 ) by a high-pressure evaporator unit ( 21 ) and at least one high-pressure preheating unit ( 23 ) with the high-pressure ORC circuit ( 20 ) and by a low-pressure Evaporator unit ( 31 ) with the low-pressure ORC circuit ( 30 ) is thermally coupled, wherein of a Heizmittelstrom the Heizmittelkreislaufs ( 10 ) downstream of the high pressure evaporator unit ( 21 ), in particular between the low-pressure evaporator unit ( 31 ) and the high-pressure preheating unit ( 23 ), a partial flow is diverted and fed into a district heating network or used to heat a district heating medium in a district heating network. A method according to claim 14, characterized in that the device for generating energy according to one of claims 1 to 12 is formed.

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