Flushing system and its use in an energy system

Description

[0001] The present invention relates firstly to a flushing system for flushing components of an energy system according to the preamble of independent patent claim 1 (see, for example, EP 3 346 532 A1). Furthermore, the invention relates to an energy system according to the preamble of independent patent claim 10. Finally, the invention also relates to a method for operating a flushing system in an energy system and to a particular use of a mixing device of a flushing system, see claims 14 and 15.

[0002] Energy systems of this type are already known in the state of the art in a variety of forms. Such systems are typically used to generate and provide energy for a wide variety of applications.

[0003] In one known type of such energy system, energy is generated in a first energy source. The generated energy can be hydrogen, for example. The hydrogen is generated, for example, in an electrolysis device and stored in a second energy source device, which can be a storage device, for example. This is, for example, a first mode of operation of the energy system. During operation of the energy system, the hydrogen is removed from the storage device and consumed in a first energy sink device. This is, for example, a second mode of operation of the energy system. Such a first energy sink device is, for example, a fuel cell device.Typically, the aforementioned components of the energy system are spatially separated from one another and connected via a connecting line. Both of the aforementioned operating modes typically require different pressure levels. While pressures of 20 to 60 bar prevail in the first operating mode with electrolysis, pressures of less than 20 bar are required for the operation of the fuel cell device in the second operating mode. Such a known energy system is disclosed, for example, in DE 103 07 112 A1.

[0004] During operation of such an energy system, it is necessary to regularly purge the fuel cell device, particularly on its anode side, and / or the electrolysis device, particularly on its cathode side. Purging, also known as "purging," is particularly necessary to remove unwanted foreign gas components, as well as liquid water that accumulates locally in the cell structures, which can negatively impact the performance and service life of the fuel cell device and / or the electrolysis device, at regular intervals or depending on the operating conditions. Purging is carried out with the aid of a suitable purging system.

[0005] US2002 / 0094469A1 describes a fuel cell system in which released hydrogen gas is diluted. For this purpose, a mixing chamber designed as a closed chamber is provided, which has inlets for hydrogen and oxygen on the input side and an outlet for a correspondingly diluted gas mixture on the output side.

[0006] Another known purging system, from which the present invention is based, is disclosed and described in WO 2017 / 089466 A1 by the applicant. In this known solution, a hydrogen-laden purging volume flow is generated during the purging process and initially stored in a storage chamber associated with a purging device. The hydrogen-laden purging volume flow is then released from the storage chamber to the environment as a discharge volume flow via an outlet device.

[0007] For example, the fuel cell device, the electrolysis device, and the purging system are components of a first subsystem of the energy system, which is housed, for example, in a system cabinet. The vent volume flow is then released into the environment in such a way that it is released via the outlet device into a specific area in the system cabinet known as the mixing zone. This area is specially designed for this purpose. Due to the hydrogen content, which represents a harmful gas at this point, the vent volume flow is an explosive gas mixture, so no ignition sources may be located near the outlet. In order to bring the hydrogen content to a value below the lower explosion rate, it is necessary to dilute the hydrogen-laden vent volume flow to such an extent that the hydrogen content in the volume flow drops below the lower explosion limit.This is achieved, for example, by mixing the discharge volume flow in the mixing zone with another air volume flow. This additional air volume flow could be, for example, an exhaust air volume flow that is generated elsewhere during operation of the energy system.

[0008] The purging process described in the known solution already works very well. Nevertheless, there is always a need to further modify the energy system to ensure that the hazards posed by escaping hydrogen, especially the risk of explosions, are safely and reliably eliminated at all times.

[0009] Based on the known solution, further developments could, for example, include the use of a dedicated fan for the dilution air volume flow. However, a fan represents an additional system component that requires energy and incurs additional costs and requires installation space. In addition, such fans would have to be designed to be suction-type and explosion-proof, as they inherently represent an ignition source. The use of additional fans is therefore disadvantageous. Furthermore, a hydrogen sensor could also be used in addition to air monitoring. However, this would complicate the operation of the purge system and thus the energy system. A hydrogen sensor can only measure a mixed concentration, and statements about the actual hydrogen concentration within the mixing zone can only be made with precise knowledge of the flow conditions. This is too imprecise, however.In addition, large safety factors must be utilized. Fault triggering is also possible. Furthermore, the use of a hydrogen sensor in itself does not constitute a measure to reduce the hydrogen content in the discharge volume flow. The use of a gas monitoring device is usually subject to a maintenance interval. For example, functional tests every four months are common.

[0010] Based on the cited prior art, the present invention is therefore based on the object of further advantageously modifying a generic flushing system by simple constructive and cost-effective measures in order to avoid explosion hazards caused by hydrogen in the discharge volume flow after a flushing process.

[0011] This object is achieved according to the invention by the flushing system having the features according to independent patent claim 1, which represents the first aspect of the invention, by the energy system having the features according to independent patent claim 10, which represents the second aspect of the invention, by the method having the features according to independent patent claim 14, which represents the third aspect of the invention, and by the special use having the features according to independent patent claim 15, which represents the fourth aspect of the invention. Further features and details of the invention emerge from the subclaims, the description, and the drawings.In this case, features and details disclosed in connection with the first aspect of the invention also apply in full in connection with the second, third and fourth aspect of the invention, and vice versa, so that with regard to the disclosure of one of the aspects of the invention, reference is always made in full to the other aspects of the invention and reference is made to them.

[0012] The basic idea of ​​the present invention is that a simple construction creates an area of ​​targeted mixing of harmful gas, which is in particular the hydrogen-containing discharge volume flow.

[0013] The invention is initially directed to a flushing system through which individual components of an energy system are flushed. The flushing system is, in particular, a whole consisting of several components, wherein the components are connected to one another to form a dedicated unit. The flushing system is preferably a component of an energy system. The energy system, in turn, is, in particular, a whole consisting of several components, wherein the components are connected to one another to form a dedicated unit. In the present case, the energy system is preferably a system for generating or providing energy, preferably electrical energy. In principle, the invention is not limited to specific types of energy systems. Various preferred exemplary embodiments are described below in this regard.

[0014] In a preferred embodiment, the energy system is a home energy system. Home energy systems are generally known from the prior art and serve to supply houses, for example low-energy houses, passive houses, or zero-energy houses, with energy in the form of heat and, in particular, in the form of electricity, for example, electricity from renewable energy sources such as photovoltaic (PV) generators or small wind turbines. Such a home energy system creates the basis for the energy requirements of a house, in particular a low-energy house, a passive house, or a zero-energy house, to be fully covered from renewable energy sources, both in terms of electricity and heat requirements, thus ensuring complete CO2-free operation.At least, however, the electricity needs of a house can be covered almost entirely from renewable energy sources, in particular by means of a PV generator and / or a small wind turbine, in order to achieve an increase in self-consumption.

[0015] Such a home energy system is disclosed and described, for example, in the applicant's patent applications WO 2017 / 089468 A1 and WO 2017 / 089469 A1, the disclosure content of which is incorporated into the description of the present patent application.

[0016] According to a preferred embodiment, a home energy system of the type mentioned has the following basic features: a DC feed point, preferably designed for a nominal voltage of 48 volts, and / or an AC feed point, preferably designed for a voltage of 230 volts or 110 volts, wherein the DC feed point and / or the AC feed point is at least temporarily connected during operation to an electrical consumer having a consumption power; a PV generator, electrically connected at least temporarily to the DC feed point, for generating electrical PV power; a fuel cell unit, electrically connected at least temporarily to the DC feed point or to the AC feed point, for generating electrical fuel cell power; an electrolysis unit, electrically connected to the DC feed point, for generating hydrogen to be consumed by the fuel cell unit, wherein the electrolysis unit is supplied with an electrical electrolysis input power during operation; a hydrogen tank;in particular as a long-term energy storage device, which is at least temporarily fluidly connected to the fuel cell unit and the electrolysis unit and is designed to store hydrogen to be generated by the electrolysis unit and consumed by the fuel cell unit, a storage battery unit, in particular as a short-term energy storage device, which is electrically connected or to be connected to the DC feed-in point, so that an electrical PV power and an electrical fuel cell power can be stored in the storage battery unit and an electrical electrolysis input power and a consumption power can be drawn from the storage battery unit; and a control module for controlling the domestic energy system.

[0017] According to the first aspect of the invention, a flushing system is provided which has the features of independent claim 1.

[0018] The purging system is provided to purge at least one energy source device and / or at least one energy sink device. These two components represent components of an energy system, which is described in detail in the general description above and in connection with the second aspect of the invention further below, so that at this point reference is also made to the corresponding explanations therein. In a preferred embodiment, based on which the invention is explained by way of example, the energy source device is preferably an electrolysis device, in particular for producing hydrogen. The energy sink device is preferably a fuel cell device.

[0019] The purging system comprises a purging device configured to generate a purge volume flow during a purging process. This purge volume flow, which contains hydrogen, which is a harmful gas at this point, arises, for example, when the fuel cell device, in particular on its anode side, and / or the electrolysis device, in particular on its cathode side, is / are purged.

[0020] Such a flushing system, also referred to as a "purge system," and which preferably comprises several different components, is explained in more detail below. The flushing itself is also referred to as "purging."

[0021] In a preferred embodiment, the purging system comprises a purging device with a purging channel having a first and at least one second purging channel section, which are fluidically connectable to one another via a purge valve of the purging device, and with a buffer storage device fluidically connected to the purging channel and downstream of the purge valve, having at least one storage chamber which is provided for the temporary storage of a fluid mass to be purged from the fuel cell device and / or the electrolysis device in a pulsed manner with a purge mass flow, so that this fluid mass can be discharged from an outflow device fluidically connected to the second purge channel section with a discharge mass flow, which is the discharge volume flow that is less than the purge mass flow.The purge mass flow, which typically consists largely of hydrogen, can be mixed with an air mass flow, which is the air volume flow, so that the resulting gas mixture has a hydrogen concentration well below the lower ignition limit of hydrogen in air under all operating conditions. This dilution effect enables safe operation of the energy system. By connecting a buffer storage unit with a storage chamber downstream of the purge valve, a fluid mass discharged in pulses with the purge mass flow can be discharged with a purge mass flow that is lower than the purge mass flow. This advantageously smooths the pulsed purge mass flow, which advantageously prevents critical hydrogen concentrations while simultaneously reducing the exhaust air mass flow.

[0022] In a preferred embodiment, the storage chamber is expandable. The storage chamber can be expanded by the fluid mass to be flushed out of the fuel cell device and / or the electrolysis device in a pulsed manner with the purge mass flow. Particularly preferably, the storage chamber is designed as a bellows that can accommodate a respective purge volume, i.e., the purge mass flow multiplied by a pulse duration of a purge, with no or only a slight buildup of counterpressure. A storage chamber designed as a bellows can be designed to be moved back into its non-expanded state by a gravitational force, in particular exclusively by a gravitational force of a preferably freely movable end plate of the bellows.To specifically adjust the force that moves the bellows back to its non-expanded state, and thus the discharge time and the pressure curve of the bellows buffer over time, the gravitational force can also be amplified or partially compensated by an attached spring device.

[0023] As already mentioned, the discharge volume flow is provided from the storage chamber, which is designed in particular as a bellows. However, the present invention is not limited to this embodiment. In another embodiment, the storage chamber can be designed as a bladder accumulator or as a piston accumulator. As an alternative to an expandable design of the storage chamber, the storage chamber can also be designed as a rigid pressure vessel, in which the storage chamber is designed such that the fluid mass flushed out in pulses with the flushing mass flow from the fuel cell device and / or the electrolysis device leads to a pressure increase in the storage chamber.

[0024] The purging system can be configured to reduce a purge volume flow to a discharge volume flow of less than 10%, preferably less than 3%, of the purge volume flow. The discharge volume flow is preferably discharged to the environment via an exhaust air volume flow of at least 50 Nm³ / h, also referred to as the exhaust air volume flow. Preferably, a nominal operating pressure of the storage chamber is less than 50 millibars, preferably less than 20 millibars, above an operating pressure of the exhaust air volume flow or exhaust air volume flow.

[0025] In other words, the purging system's primary function is to ensure that an air volume flow surrounds the purge chamber outlet, for example, the purge bellows outlet, and dilutes the hydrogen being purged from the electrolysis unit and / or the fuel cell unit. The purging process is also known as purging in technical jargon and is necessary for the safe operation of both modules. Purging the stacks with pure hydrogen removes impurities and moisture. Targeted mixing with an air volume flow, which could be an exhaust air volume flow, for example, prevents the formation of an explosive atmosphere. The exhaust air can then be routed through a cooling system, such as an air-water heat exchanger.There, either the excess heat from the electrolysis system can be removed or the warm exhaust air can be used to heat water in a hygienic hot water tank. The resulting exhaust air is directed outside.

[0026] Such a flushing system is disclosed and described, for example, in the applicant's patent application WO 2017 / 089466 A1, the disclosure content of which is incorporated into the description of the present patent application.

[0027] According to the invention, the purging system comprises a mixing device arranged downstream of the purging device in the flow direction of the discharge volume flow. The mixing device is, in particular, designed to mix the discharge volume flow with another air volume flow. The another air volume flow is preferably an air volume flow that arises elsewhere during operation of the energy system, for example an exhaust air volume flow. Mixing the two volume flows in the mixing device results in the hydrogen-laden discharge volume flow being diluted to such an extent that the hydrogen content is pushed below the lower explosion limit, preferably to a content of not less than 10,000 ppm (1 vol%).

[0028] Preferably, the mixing device is a component assigned to the flushing system. It is therefore preferably considered a component of the flushing system. However, the mixing device can just as easily be located downstream of the flushing system. In this case, the mixing device would no longer be considered a component of the flushing system, but rather an independent component that interacts with the flushing system.

[0029] According to the invention, the mixing device has a wall that delimits a defined open mixing space for mixing the discharge volume flow with the air volume flow, in particular with defined flow conditions. The space partially delimited by the wall of the mixing device is, in particular, the location where the mixing takes place. The term "space" is therefore to be understood both physically, i.e., with a physical boundary, and functionally. The space is only partially delimited by the wall. Such a space is referred to as an open space because it is only partially and regionally surrounded and delimited by the wall. The wall serves the function of spatially delimiting or limiting the mixing space.An open mixing chamber is characterized in particular by being as open as possible over a large area and / or in as many places as possible, so that the various volume flows can mix well. Various preferred embodiments of this will be explained in more detail later in the description.

[0030] The flushing system preferably has an outflow device that interacts with the mixing device. In this case, interaction means in particular that the outflow device works together or cooperates with the mixing device. In particular, it is provided that the outflow device and the mixing device are arranged so close to one another that the discharge volume flow from the outflow device can enter the mixing device. The invention is not limited to specific embodiments for the outflow device. For example, the outflow device can be designed in the form of an orifice, throttle, nozzle, jet pump, Venturi nozzle or as a recombiner. The outflow device has the particular function of limiting the discharge volume flow entering the mixing chamber or of providing a defined discharge volume flow for entry into the mixing chamber.

[0031] In a preferred embodiment, the mixing device has a distribution device that is designed and provided to distribute the discharge volume flow in the mixing chamber. The basic function of this distribution device is to distribute the discharge volume flow in the mixing chamber in such a way that it can mix as well and preferably evenly as possible with the air volume flow. The distribution device preferably interacts with the outflow device, preferably in such a way that the distribution device is directly connected to the outflow device. The distribution device is preferably arranged or formed at least partially in the mixing chamber. In a preferred embodiment, the distribution device is arranged entirely in the mixing chamber. In another configuration, the distribution device is only partially arranged in the mixing chamber.This means that the distribution device protrudes from the mixing chamber in some areas.

[0032] The invention is not limited to specific embodiments of this distribution device.

[0033] In a preferred embodiment, the distribution device is designed in the form of a, in particular elongated, pipe or profile element which extends at least partially, preferably over the entire length or approximately the entire length of the mixing chamber.

[0034] In a further preferred embodiment, the distribution device consists of a porous material. The discharge volume flow then penetrates the pores of the distribution device. The distribution device is thus capable of controlling the flow of the discharge volume flow, for example, in a preferred flow direction, and / or limiting and / or possibly also damming it. This enables the discharge volume flow to be distributed as evenly as possible and / or, if necessary, to enter the mixing chamber at reduced pressure, so that it can mix as evenly as possible with the air volume flow in the mixing chamber.

[0035] To ensure that the mixing chamber of the mixing device is designed to be as open as possible, the invention provides that the wall of the mixing device delimits only a portion of the mixing chamber. The area of ​​the mixing device not delimited by the wall forms an inlet area for the discharge volume flow and the air volume flow. According to the invention, the wall of the mixing device delimits the mixing chamber by less than 90%, preferably by less than 80%, preferably by less than 70%, preferably by less than 60%, preferably by less than 50%.

[0036] Depending on the design, the inlet area can be configured so that the discharge volume flow and the air volume flow enter the mixing chamber separately, each via their own inlet sections. In another design, the discharge volume flow and the air volume flow can enter the mixing chamber, at least partially, via a common inlet section.

[0037] In a preferred embodiment, the mixing device has at least one element for increasing the residence time of the discharge volume flow in the mixing device. This increases the residence time of the hydrogen within the "protected" environment of the mixing device and thus also the time for thorough mixing. The invention is not limited to specific types of such elements. For example, it can be a nonwoven element, a Styrofoam element, a masking tape, or the like.

[0038] The present invention is not limited to specific embodiments of the mixing device's design. A series of preferred embodiments are described below, without limiting the invention to these specific examples.

[0039] For example, the mixing device can be hood-shaped, umbrella-shaped, or bowl-shaped, or the mixing device can have an arcuate wall. However, the mixing device can also have the shape of a dome or a curved shape. Other shapes, such as a bell, in particular a cheese dome, a funnel, a pyramid, or the like, are also conceivable. The contour of the mixing device is realized in particular by a corresponding shape or a corresponding design of the wall of the mixing device.

[0040] In another preferred embodiment, the mixing device is designed in the form of a fragment of a pipe, wherein the wall of the pipe fragment defines the mixing space. For example, a distribution device as described above, for example in the form of a pipe made of porous material, can be located therein. A pipe is, in particular, an elongated hollow body, which in particular has a length that is greater, preferably many times greater, than its cross-section. A solid pipe is a pipe whose wall completely surrounds the interior of the pipe from all sides. The fraction of a pipe is a partial segment of such a solid pipe.

[0041] For example, the mixing device can be designed in the form of a quarter tube, a third tube, a three-quarter tube, or a two-thirds tube. In a preferred embodiment, the mixing device is designed in the form of a half tube, with the wall of the half tube defining the mixing space.

[0042] The discharge volume flow is preferably slowed down by the path in the mixing device. This is why it is preferably designed as long as possible, for example, as a half-pipe as long as possible, and with a large mixing surface.

[0043] In such a case, the mixing device preferably has a first open front side and / or an open underside. The first front side and / or the open underside serve in particular as an entry point or entry surface or entry region for the discharge volume flow into the mixing chamber of the mixing device. The open underside serves in particular as an entry point or entry surface or entry region for the air volume flow with which the discharge volume flow mixes. The underside of the semi-tubular mixing device represents in particular its base side or base side. The surface formed by the underside, which is delimited by the free end regions of the curved wall, forms the plane from which the curved wall of the half-tube extends or curves upwards.Alternatively or additionally, the half-pipe also has an open second end face, which is designed in particular as an outlet side for an exhaust air flow consisting of the mixed discharge volume flow and the air volume flow.

[0044] Instead of a pipe, in particular a half pipe, the mixing device can also be designed in the form of a differently shaped profile element fraction, for example a half profile element.

[0045] The contour of the mixing device preferably defines a shape for a hypothetical volume with respect to the mixing of the discharge volume flow with the exhaust air volume flow, in particular with defined flow conditions. A hypothetical volume is in particular one based on an assumption or presumption. Preferably, there are no ignition sources in the hypothetical volume. This applies in particular when the mixing device is installed in an energy system. In a semi-tubular mixing device, the hypothetical volume preferably has the shape of a cylinder that surrounds the mixing device on all sides.

[0046] According to the second aspect of the invention, an energy system is provided which has the features of independent claim 10.

[0047] The invention system is in particular a home energy system.

[0048] The energy system comprises an energy source device, which is designed in particular as an electrolysis device, preferably for producing hydrogen. Additionally or alternatively, the energy system comprises an energy sink device, which is designed in particular as a fuel cell device. Furthermore, the energy system can optionally comprise a second energy source device, which is designed in particular as a high-pressure storage device, in particular for storing hydrogen, and / or a second energy sink device, which is preferably designed as a medium-pressure storage device, in particular for temporarily storing hydrogen.

[0049] The energy system also has a purging system for purging the energy source device and / or the energy sink device, which is designed according to the first aspect of the invention. For a description of the structure and functioning of the energy system, reference is also made in full to the general explanations above as well as to the explanations regarding the purging system according to the invention.

[0050] In a preferred embodiment, the energy system comprises a first subsystem, which is arranged in particular in a system cabinet. The energy source device and / or the energy sink device as well as the purging system are then components of the first subsystem. The first subsystem comprises a mixing zone, which is provided in such a way that the discharge volume flow and the air flow, in particular the exhaust air volume flow, are mixed or can be mixed therein. The mixing device is preferably arranged or formed in the mixing zone.

[0051] The energy system preferably has at least one cooling device, which has already been generally described above and is designed in particular as an emergency cooler. The mixing device is preferably arranged or designed below the cooling device.

[0052] According to the third aspect of the invention, a method is provided which has the features of independent claim 14.

[0053] According to the method, a flushing system is operated according to the first aspect of the invention. The flushing system is, in particular, a component of an energy system according to the second aspect of the invention. To avoid repetition, reference is made in full to the above explanations regarding the first and second aspects of the invention, as well as to the general explanations above, regarding the functioning of the method.

[0054] According to the method according to the invention, a discharge volume flow generated in the purging system during a purging process is directed into the defined open mixing chamber delimited by the wall of the mixing device, where it is mixed with an air volume flow, in particular an exhaust air volume flow, and from there discharged as an exhaust air volume flow. The exhaust air volume flow preferably flows through a distribution device described above in the mixing chamber, for example, a pipe made of porous material. The air volume flow is in particular one that arises elsewhere during operation of the energy system.

[0055] According to the fourth aspect of the invention, a mixing device according to independent claim 15 is used in a special manner. With regard to the design of the mixing device, reference is made in full to the corresponding statements within the scope of the first to third aspects of the invention, as well as to the general statements above, in order to avoid repetition.

[0056] Accordingly, a mixing device is used which has a wall that delimits a defined open mixing space, wherein the wall only delimits a partial area of ​​the mixing space of less than 90%, and the area of ​​the mixing device not delimited by the wall forms an inlet area for at least two volume flows. This mixing device is used to mix a discharge volume flow generated by a purging system, in particular a purging system according to the first aspect of the invention, during a purging process of an energy source device and / or an energy sink device of an energy system, in particular an energy system according to the second aspect of the invention, with an air volume flow generated by the energy system elsewhere, in particular an exhaust air volume flow.The use provides in particular that the discharge volume flow, which contains hydrogen, which is a harmful gas at this point, is sufficiently diluted by the mixing.

[0057] The present invention, according to its various aspects, is based in particular on the problem that the release of hydrogen into an air flow must occur below the lower explosion limit. This always creates an explosive atmosphere, which is considered hazardous. Therefore, any dilution of the hydrogen must be carried out in a state where a targeted flow cannot be used. Furthermore, the required flow should be as low as possible to ensure very low energy consumption.

[0058] The present invention therefore consists in particular in that by means of a construction, namely the mixing device, in particular the definition of a hypothetical volume is made possible which is sufficiently ventilated so that an average concentration of the harmful gas < 50% of the lower explosion limit and the considered volume remains < 0.1m 3 <. With strong ventilation and good availability, a potential Zone 0 thus becomes a non-explosive area. The air flow used for mixing with the discharge volume flow can, for example, be an exhaust air volume flow from the energy system, for example the domestic energy system. Possible ignition sources can be provided in the subsequent flow path after the mixing device.The hydrogen-containing discharge volume flow is introduced from the purge system, for example, a purge chamber, into the mixing device, where it experiences an extended residence time in a defined open space for thorough mixing. For safety reasons, no ignition sources should be present within the hypothetical volume.

[0059] The present invention allows for a number of advantages. For example, a simple design solution can be provided for a fixed, bypassing ventilation space with defined inflow conditions. Additional hydrogen sensors are not required. The contour of the mixing device gives the hypothetical volume a shape.

[0060] The invention will now be explained in more detail using an exemplary embodiment with reference to the accompanying drawings. Figure 1 shows a schematic view of an energy system according to the invention with a flushing system according to the invention; and Figures 2 to 4 show three different views relating to the mixing device of the flushing system.

[0061] In the Figures 1 to 4 An energy system 10 is shown schematically, which is used as a home energy system. In Figure 1 First, the basic structure of the energy system 10 is described.

[0062] As from Figure 1As can be seen, the energy system 10 initially has a first subsystem 11, which is designed as an indoor system. This means that the first subsystem 11 is located inside the house. The individual components of the first subsystem 11 are housed in a first system cabinet 12. In addition, the energy system 10 has a second subsystem 13 in the form of an outdoor system. This means that the second subsystem 13 is located outside the house. The second subsystem 13 also has a number of different components, which are housed in a second system cabinet 14.

[0063] The first subsystem 11 has a first energy source device 15, which is an electrolysis device for producing hydrogen. The first subsystem 11 also has a first energy sink device 16, which is a fuel cell device. The second subsystem 13 has a second energy source device 22, which is a high-pressure storage device. The hydrogen produced in the electrolysis device is stored in the high-pressure storage device at up to 700 bar. In addition, the second subsystem 13 has a second energy sink device 23 in the form of a medium-pressure storage device, in which the produced hydrogen is temporarily stored at pressures between 20 and 60 bar before it is finally stored in the high-pressure storage device.

[0064] The individual components of the energy system 10 are connected to one another via a connecting line device 17, which consists of a number of different line sections. Individual line sections are designed as so-called bidirectional line sections.

[0065] For flushing the first energy source device 15 and / or the first energy sink device 16, a flushing system 40 is provided, the structure and functioning of which are described in more detail below.

[0066] The hydrogen generated by electrolysis in the first energy source device 15 leaves the first energy source device 15 via a line section of the connecting line device 17, which, in the flow direction of the generated hydrogen, contains, for example, a check valve device 18 and, subsequently, a filter device 19 and a dryer device 20 in which the generated hydrogen is filtered and dried. Alternatively, the filter device 19 and the dryer device 20 can also be located in the second subsystem 13.

[0067] From the dryer device 20, the generated hydrogen flows via further line sections of the connecting line device 17 to a further check valve device 26 in the second subsystem 13. From there, the generated hydrogen flows into the second energy sink device 23, which functions as a medium-pressure accumulator and is connected to the connecting line device 17 via a valve device 24, which is designed in particular as a shut-off valve, for example in the form of a solenoid valve. A compressor device 25, in particular in the form of a piston compressor, is located in the connecting line device 17 upstream of the second energy source device 22, designed as a high-pressure storage device. The hydrogen temporarily stored in the second energy sink device 23 is stored in the second energy source device 22 by actuating the compressor device 25.

[0068] This hydrogen production process up to its storage in the second energy source device 22 represents a first mode of operation of the energy system 10. In this first mode of operation of the energy system 10, a pressure of 20 to 60 bar prevails in the connecting line device 17. A similar pressure also prevails in the second energy sink device 23. The compressor device 25 compresses the hydrogen extracted from the second energy sink device 23, which is an intermediate storage device, to such an extent that it can be stored at pressures of up to 700 bar in the second energy source device 22, which is a high-pressure storage device.

[0069] The hydrogen stored in the second energy source device 22 is used to operate the first energy sink device 16 in the form of the fuel cell device. The fuel cell device operates in the second operating mode of the energy system 10. However, the fuel cell device can only operate at pressures below 20 bar. In the second operating mode of the energy system 10, the hydrogen is extracted from the second energy source device 22 and expanded via an expansion device 27 in the form of a pressure reducer before entering the first energy sink device 16 designed as a fuel cell device. At least one pressure measuring device 21, for example in the form of a pressure sensor, is provided to measure the pressure.

[0070] The Figures 1 to 4The energy system 10 shown represents a sub-area of ​​an overall home energy system, which is an electrically self-sufficient and completely renewable energy-based multi-hybrid home energy storage system.

[0071] The multi-hybrid home energy storage system makes it possible to distribute the electrical energy generated by a photovoltaic (PV) system, a small wind turbine, or similar system as needed throughout the year. The system operates as an off-grid system, independent of the electrical grid. Rather, the system is designed to ensure the home's electrical self-sufficiency, eliminating the need to draw electrical energy from the grid throughout the year.

[0072] The primary task of a home energy system is to make the electrical energy generated from photovoltaic (PV) modules or similar devices available to the consumer in the home. Secondarily, surplus electrical energy can be temporarily stored in a short-term battery storage system during periods of low load or high irradiation. Tertiary, the electrical energy can be stored as gaseous hydrogen in a long-term hydrogen storage system for medium- to long-term periods during periods of low irradiation, such as night, winter, or similar periods, and then made available again at any time as needed using a fuel cell.

[0073] In addition to energy-related tasks, the system also functions as controlled living space ventilation through a built-in ventilation unit.

[0074] The hydrogen produced in the electrolysis plant flows via the hydrogen pipeline into the external pressure storage system.

[0075] If PV energy is missing or insufficient, energy is drawn from the battery to cover the consumer load. If the energy stored in the short-term storage system is insufficient, the fuel cell system can cover the additional electrical energy demand. In fuel cell operation, the hydrogen flows from the pressure storage system to the fuel cell system via the hydrogen line.

[0076] Simultaneous operation of the fuel cell system and the electrolysis system is impossible. The entire system is operated centrally via an energy manager with predictive energy management.

[0077] The second subsystem is principally intended for outdoor operation, but under certain conditions can also be installed and operated within a specific area of ​​the house.

[0078] During operation of the energy system 10, it is necessary for the first energy source device 15 in the form of the electrolysis device and the first energy sink device 16 in the form of the fuel cell device to be regularly purged, with the fuel cell device being purged particularly on the anode side and the electrolysis device being purged particularly on the cathode side. Purging is particularly necessary to remove unwanted foreign gas components, as well as liquid water accumulating locally in the cell structures, which can negatively impact the performance and service life of the fuel cell device and / or the electrolysis device, at regular intervals or depending on the operating conditions.

[0079] Flushing is carried out with the aid of the flushing system 40. In a conventional manner, the flushing system 40 initially comprises a flushing device 41, which may, for example, have at least one storage chamber, such as a bellows. During the flushing process, a discharge volume flow 42 containing hydrogen, which represents a harmful gas at this point, emerges from the flushing device 41. This essentially creates an explosive atmosphere, making it necessary to reduce the release of hydrogen during the flushing process to below the explosion limit.This has previously been achieved, for example, by mixing the hydrogen-containing discharge volume flow 42 with an air flow 28 of the energy system 10, in particular an exhaust air volume flow, in a mixing zone 29 of the first system cabinet 12, which represents a zone designed and constructed for this purpose and is equipped with appropriate safety measures, such that the hydrogen content in the resulting exhaust air volume flow 30 is only below the explosion limit, for example, less than 2%. The discharge of the discharge volume flow 42 into the environment, i.e., into the mixing zone 29, generally takes place via a suitable discharge device 43, which can be designed, for example, as an orifice, throttle, nozzle, or the like.The exhaust air volume flow 30 resulting from the mixing is discharged from the first subsystem 11 or the first system cabinet 12 via an exhaust air duct 31 and can be made available for other functions, for example ventilation and / or heating and / or cooling.

[0080] In the flow direction of the discharge volume flow 42 behind the flushing device 41, preferably in the mixing zone 29, there is now a further component in the form of a mixing device 44. This mixing device 44 is described in detail in the Figures 2 to 4 which will now be discussed in more detail.

[0081] The mixing device 44, which is located in the first subsystem 11, preferably below a cooling device 32 in the form of an emergency cooler ( Figure 4), has a wall 47 that delimits a defined, open mixing chamber 45. In this case, and in accordance with the invention, the wall 47 of the mixing device 44 delimits only a partial area of ​​the mixing chamber 45. The area of ​​the mixing device 44 not delimited by the wall 47 forms, in accordance with the invention, an inlet area 48 for the discharge volume flow 42 and for the air volume flow 28 into the mixing chamber 45.

[0082] In the exemplary embodiment shown, the mixing device 44 is designed in the form of a half-pipe. This half-pipe has a first open end face 49 and an open underside 51. The end face 49 and / or the underside 51 serve as the inlet side for the hydrogen discharge volume flow 42 exiting the outflow device 43. The open underside 51 of the half-tubular mixing device 44 also provides, in particular, an inlet surface through which the air volume flow 28, in particular the exhaust air volume flow, enters the mixing chamber 45. The air volume flow 28 can enter the mixing chamber 45 via the entire open underside 51. The design of the mixing device 44 creates a hypothetical volume 46 that defines the purge zone.

[0083] At the Figure 2In the embodiment shown, the discharge volume flow 42 enters the mixing chamber 45 via the discharge device 43 in the inlet area 48, is distributed there and mixes with the air volume flow 28.

[0084] In order to influence the flow properties of the discharge volume flow 42 in the mixing chamber 45, in particular with regard to its flow properties, such as the flow path, and in order to limit and / or dam the flow of the discharge volume flow 42 in the mixing chamber 45, a further component in the form of a distribution device 52 is preferably provided, which in Figure 3 The distribution device 52 is preferably designed as a tube made of porous material. In Figure 3For clarity, some pores 53 are indicated schematically. The tubular distribution device 52, made of porous material, extends over the entire length or approximately the entire length of the mixing chamber 45. The distribution device 52 preferably interacts with the outflow device 43 such that the discharge volume flow 42 leaving the outflow device 43 enters the distribution device 52 directly or as directly as possible. Due to the porous material, the discharge volume flow 42 penetrates the distribution device 52, thereby influencing its flow properties. Via the pores 53 of the distribution device 52, the discharge volume flow 42 then exits the distribution device 52 at various points and enters the mixing chamber 45, where it mixes with the air volume flow 28 as evenly as possible and preferably under a preferred reduced pressure.

[0085] How to Figure 4As can be seen, the hypothetical volume 46 in this semi-tubular mixing device 44 preferably has the shape of a cylinder that extends around the mixing device 44. In the example shown, the exhaust air volume flow 30 resulting from the mixing is diverted via a second open end face 50 of the mixing device 44. In principle, it is irrelevant for the present invention where the exhaust air flow originates. However, it is preferably provided that the exhaust air volume flow 30 is directed via the cooler device 32, where the exhaust air volume flow 30 can be further used either for heating purposes or for cooling purposes, if necessary or desired.

[0086] By using the mixing device 44, the hydrogen discharged from the purging device 41, in particular from the bellows, is mixed with an increased residence time in the defined open mixing space 45 of the mixing device 44. Care must be taken to ensure that there are no ignition sources in the vicinity of the mixing device 44, preferably within the hypothetical volume 46.

[0087] The mixing has the effect that the hydrogen-laden discharge volume flow 42 is diluted by the mixing with the air volume flow 28, which is in particular an exhaust air volume flow that is created or generated elsewhere in the energy system 10, to such an extent that the hydrogen in the discharge volume flow 42 always falls below a critical content limit, which is, for example, less than 2%. List of reference symbols

[0088] 10 Energy system (house energy system) 11 First subsystem (indoor system) 12 First system cabinet 13 Second subsystem (outdoor system) 14 Second system cabinet 15 First energy source device (electrolysis device) 16 First energy sink device (fuel cell device) 17 Connecting line device 18 Check valve device 19 Filter device 20 Dryer device 21 Pressure measuring device 22 Second energy source device (high-pressure storage device) 23 Second energy sink device (medium-pressure storage device) 24 Valve device 25 Compressor device 26 Check valve device 27 Expansion device (pressure reducer) 28 Air volume flow (exhaust air volume flow) 29 Mixing zone 30 Exhaust air volume flow 31 Exhaust air duct 32 Cooler device (emergency cooler) 40 Purging system 41 Purging device 42 Discharge volume flow 43 Discharge device 44Mixing device 45Mixing chamber 46Hypothetical volume (flushing zone) 47Wall of the mixing device 48Inlet area of ​​theMixing device 49First end of the mixing device 50Second end of the mixing device 51Underside of the mixing device 52Distribution device 53Pores

Claims

1. A purging system (40), which is provided in order to purge at least one energy source device (15) and / or at least one energy sink device (16), comprising a purging device (41) which is provided in such a way that it is capable to generate a discharge volume flow (42) during a purging process, wherein the purging system (40) comprises a mixing device (44), being provided, in flow direction of the discharge volume flow, downstream the purging device (41), which is provided for mixing the discharge volume flow (42) with an air volume flow (28), characterized in that the mixing device (44) comprises a defined open mixing space (45) for mixing the discharge volume flow (42) with the air volume flow (28), in that the mixing device (44) for this purpose comprises a wall (47), in that the wall (47) delimits only a partial region of the mixing space (45) to less than 90%, and in that the region of the mixing device (44), which is not limited by the wall (47), forms an entrance area (48) for the discharge volume flow (42) and the air volume flow (28).

2. The purging system according to claim 1, characterized in that the purging system (40) comprises an outflow device (43) which interacts with the mixing device (44), and that, in particular, the outflow device (43) is configured as a diaphragm, throttle, nozzle or pump.

3. The purging system according to claim 1 or 2, characterized in that the mixing device (44) comprises a distribution device (52) for distributing the discharge volume flow (42) in the mixing space (45), and in that the distribution device (52) is arranged at least partially in the mixing space (45).

4. The purging system according to claim 3, characterized in that the distribution device (52) is configured in the form of a pipe and / or in that the distribution device (52) consists at least partially of a porous material.

5. The purging system according to anyone of claims 1 to 4, characterized in that the purging device (41) comprises at least one storage chamber, in that the discharge volume flow (42) is or gets provided from the storage chamber, and in that the storage chamber is configured in particular as a bellows.

6. The purging system according to anyone of claims 1 to 5, characterized in that the mixing device (44) is of a hood-shaped or an umbrella-shaped or a shell-shaped design, or in that the mixing device (44) has an arc-shaped wall.

7. The purging system according to anyone of claims 1 to 6, characterized in that mixing device (44) is provided in the form of a fraction of a pipe, and in that its wall delimits the mixing space (45).

8. The purging system according to claim 7, characterized in that the mixing device (44) comprises a first open end face (49) and / or in that the mixing device (44) comprises an open underside (51) and / or in that the mixing device (44) comprises a second open end face (50).

9. The purging system according to anyone of claims 1 to 8, characterized in that the contour of the mixing device (44) presets a shape for a hypothetical volume (46) with regard to the mixing of the discharge volume flow (42) with the air volume flow (28).

10. An energy system (10), comprising an energy source device (15), which is configured as an electrolysis device, and / or comprising an energy sink device (16), which is configured as a fuel cell device, and comprising a purging system (40) for purging the energy source device (15) and / or the energy sink device (16), characterized in that the purging system (40) is configured according to anyone of claims 1 to 9.

11. The energy system according to claim 10, characterized in that the energy system (10) comprises a first subsystem (11), in that the energy source device (15) and / or the energy sink device (16) and the purging system (40) are components of the first subsystem (11), in that the first subsystem (11) comprises a mixing zone (29) which is provided in such a way that therein the discharge volume flow (42) and the air volume flow (28), in particular the exhaust air volume flow, are mixed or can get mixed, and in that the mixing device (44) is arranged or provided in the mixing zone (29).

12. The energy system according to claim 11, characterized in that the first subsystem (11) is arranged in a first system cabinet (12),13. The energy system according to anyone of claims 10 to 12, characterized in that it comprises at least one cooler device (32), and in that the mixing device (44) is arranged or provided below the cooler device (32).

14. A method for operating a purging system (40) according to anyone of Claims 1 to 9, or an energy system (10) according to anyone of Claims 10 to 13, characterized in that a discharge volume flow (42), which has been generated in the purging system (40) during a purging process, is led into the defined open mixing space (45) delimited by the wall (47) of the mixing device (44), is mixed there with an air volume flow (28), in particular an exhaust air volume flow, and is discharged from there as an exhaust air volume flow (30).

15. Use of a mixing device (44), which comprises a wall (47) that delimits a defined open mixing space (45), wherein the wall (47) delimits only a partial region of the mixing space (45) to less than 90%, and the region of the mixing device (44) that is not delimited by the wall (47), forms an entrance area (48) for at least two volume flows, in order to mix a discharge volume flow (42), that has been generated by a purging system (40) during a purging process of an energy source device (15) and / or an energy sink device (16) of an energy system (10), with an air volume flow (28), generated by the energy system (10) at a different point.