METHOD FOR STORING A MEDIUM IN A PRESSURE ACCUMULATOR DEVICE

Abstract

The present invention relates, inter alia, to a method for storing a medium, in particular a gas, in a pressure storage device (31), wherein, in a preferred embodiment, a dynamic operating pressure, which is dependent on measured temperature values and up to which the medium can be stored in the pressure storage device (31), is determined. In particular, the invention allows dynamic storing of medium in the pressure storage device (31) in respect of the storage pressure, in particular the operating pressure, with a simple design. This is achieved by the dynamic operating pressure being determined, in particular calculated, on the basis of dynamic reference temperature values as a function of time. The method is preferably carried out in an energy system (10), having at least one energy source device (21) for generating a medium and a pressure storage device (31), spatially separated therefrom, for storing the generated medium.

Claims

1. A method for storing a medium, in particular a gas, into a pressure storage device (31), in which the operating pressure, up to which the medium may be stored in the pressure storage device, is determined in the form of a dynamic operating pressure (P.sub.dyn) dependent on the temperature, characterized in that the dynamic operating pressure (P.sub.dyn) is a variable operating pressure, in that the dynamic operating pressure (P.sub.dyn) is determined, in particular calculated, on the basis of defined dynamic reference temperature values (T.sub.ref) with time-related dependency, which are or get determined for specific points of time, and in that, after the dynamic operating pressure (P.sub.dyn) has been determined, the medium is stored in the pressure storage device maximally up to the dynamic operating pressure (P.sub.dyn).

2. The method according to claim 1, characterized in that the dynamic operating pressure (P.sub.dyn) is changed and/or adjusted and/or adapted over time on the basis of the dynamic reference temperature values (T.sub.ref).

3. The method according to claim 1, characterized in that the dynamic reference temperature values (T.sub.ref) are/get provided as a function of the time T.sub.ref=f(t), and in that the dynamic reference temperature values (T.sub.ref) are/get provided in particular with a calendric dependency T.sub.ref=f(dd:mm:yy).

4. The method according to claim 1, characterized in that the dynamic reference temperature values (T.sub.ref) are predetermined and/or predicted and/or calculated temperature values.

5. The method according to claim 1, characterized in that the dynamic operating pressure (P.sub.dyn) is determined in that temperature values are determined with respect to the pressure storage device (31), and in that said determined temperature values are set in relation to the defined dynamic reference temperature values (T.sub.ref).

6. The method according to claim 5, characterized in that, for the determination of the dynamic operating pressure (P.sub.dyn), values of the ambient temperature (T.sub.amb) of the pressure storage device (31) and/or temperature values of the pressure storage device (31) are provided as determined temperature values.

7. The method according to claim 5, characterized in that the dynamic operating pressure (P.sub.dyn) is determined according to the formula
P.sub.dyn=P.sub.stat×(T.sub.amb/T.sub.ref)

8. The method according to claim 1, characterized in that the dynamic operating pressure (P.sub.dyn) is determined in that, during the course of the method, at two or more time values being different from each other, which are determined in particular, a reference temperature value (T.sub.ref) is determined at each time value, and, at each time value, the dynamic operating pressure (P.sub.dyn) is then determined on the basis of the determined reference temperature values (T.sub.ref), preferably calculated, in particular modified and/or adjusted and/or adapted.

9. The method according to claim 8, characterized in that a number of reference time values (57) are stored in a comparison table (55), in that a reference temperature value (T.sub.ref) is assigned to each reference time values (57), in that the time values are compared with the reference time values (57) in the comparison table (55), and in that, if a time value matches with one reference time values (57), the dynamic operating pressure (P.sub.dyn) is determined, preferably calculated, in particular modified and/or adjusted and/or adapted on the basis of the reference temperature value (T.sub.ref) assigned to the corresponding reference time value (57).

10. The method according to claim 1, characterized in that, if the determined dynamic operating pressure (P.sub.dyn) is higher than a static operating pressure (P.sub.stat) specified by the manufacturer of the pressure storage device (31), the medium is stored in the pressure storage device (31), after the dynamic operating pressure (P.sub.dyn) has been determined, up to the static operating pressure (P.sub.stat).

11. A computer program product, which enables a data processing device (53), as soon as the computer program product is executed in the data processing device (53), and is preferably stored in a storage device (54) assigned to the data processing device, to carry out a method according to claim 1.

12. A control device (50), which is provided in order to control the storage of a medium in a pressure storage device (31), wherein the control device (50) is configured in such a way that it is capable to carry out the method according to claim 1 and/or in that the control device (50) comprises a data processing device (53) or an interface to an external data processing device.

13. An energy system (10), in particular a house energy system, comprising at least one energy source device (21) for generating a medium and a spatially spaced apart pressure storage device (31) for storing the generated medium, characterized in that the energy system (10) comprises a control device (50) according to claim 12, or in that the energy system (10) is provided in such a way that it is capable to carry out the method according to claim 1.

14. The control device (50) according to claim 12, wherein a computer program product is executed in the data processing device (53).

15. The control device (50) according to claim 14 wherein the computer program product enables a data processing device (53), as soon as the computer program product is executed in the data processing device (53), and is preferably stored in a storage device (54) assigned to the data processing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The invention will now be explained in more detail with reference to an exemplary embodiment with reference to the accompanying drawings, wherein

[0061] FIG. 1 is a schematic view of an energy system 10, in which the method according to the invention can be carried out; and

[0062] FIG. 2 depicts an example for a comparison file being provided as a comparison table, which is used during the method according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] In the embodiment, the energy system 10 is used as a house energy system. In the energy system 10, among other things, the method according to the invention is carried out. At first, the general structure of the energy system is described. Later, the course of the method is explained.

[0064] Energy system 10 initially comprises a first subsystem 20 which is configured as an inner system. That is, the first subsystem 20 is provided inside the house. In addition, the energy system 10 comprises a second subsystem 30 in the form of an outer system. That is, the second subsystem 30 is external to the house.

[0065] The first subsystem 20 comprises a first energy source device 21, which is provided as an electrolysis device for producing hydrogen. In addition, the first subsystem 20 comprises a first energy sink device 22, which is provided as a fuel cell device.

[0066] The second subsystem 30 comprises a second power source device 31, which is provided as a pressure storage device 31, in particular as a high-pressure storage device. The hydrogen produced is stored in the pressure storage device 31 at up to 700 bar. In addition, the second subsystem 30 comprises a second energy sink device 32 in the form of a medium-pressure storage device, in which the produced hydrogen is intermediately stored at pressures between 20 and 60 bar, before it is finally stored in the pressure storage device 31.

[0067] The individual components of energy system 10 are connected with one another via a connecting line device 40, which consists of a number of line sections. At least one line section 40a is configured as a so-called bidirectional line section. This means that line section 40a is bidirectionally used during operation of the energy system 10 and is flown through in both directions. In the embodiment shown the bidirectional line section 40a connects the components of the first subsystem 20 to the components of the second subsystem 30.

[0068] The first energy source device 21 is connected to the connecting line device 40 via a valve device 23. The first energy sink device 22 is connected to the connection device 40 via a valve device 24. The valve devices 23, 24 are preferably shut-off valves, for example solenoid valves.

[0069] As shown in FIG. 1, the first energy source device 21 and the first energy sink device 22 are provided on a first side 41 of the bidirectional line section 40a, whilst the pressure storage device 31 and the second energy sink device 32 are provided on a second side 42 of the bidirectional line section 40a.

[0070] The hydrogen produced in the first energy source device 21 by means of electrolysis leaves the first energy source device 21 via the connecting line device 40 and flows in particular via the bidirectional line section 40a into the second subsystem 30 and there via a check valve device 33 into the second energy sink device 32 functioning as the medium-pressure storing device. The second energy sink device 32 serves as an intermediate storage device for the hydrogen.

[0071] By means of a compressor device 34, which is in particular in the form of a piston compressor, the hydrogen intermediately stored in the second energy source device 32 is stored in the pressure storage device 31, which in particular is a high-pressure storage device. The hydrogen is compressed by the compressor device 34 to such an extent that it can be stored in the pressure storage device 31 at pressures of up to 700 bar.

[0072] The hydrogen stored in the pressure storage device 31 is used for the operation of the first energy sink device 22 in the form of the fuel cell device. However, the fuel cell device can only operate at pressures of less than 20 bar. Therefore, the hydrogen stored in the pressure storage device 31 is removed from the pressure storage device 31, is guided via a valve device 35, which can be a shut-off valve, in particular a solenoid valve, and is guided to an expansion device 36 in the form of a pressure reducer. The hydrogen can then, in particular, flow through a flow limiting device 37, which is preferably configured as a device for reducing the line cross-section. From there, the pressure reduced hydrogen is supplied via the connecting line device 40, and in this case in particular also via the bidirectional line section 40a, to the first energy sink device 22 in the form of the fuel cell device and consumed there.

[0073] To measure the ambient temperature, a corresponding temperature measuring device 52 is assigned to the pressure storage device 31. The detected temperature values of the temperature measuring device 52 are transmitted via an interface 51 to a control device 50, in which and with which the method according to the invention is carried out. For this purpose, the control device 50 comprises a data processing device 53, which is connected to a storage device 54 via a data exchange connection 56. In the storage device 54, a comparison file in the form of a comparison table 55 is stored, which is shown in FIG. 2.

[0074] The energy system 10 illustrated in FIG. 1 represents a partial area of an overall house energy system, which is a multi-hybrid house energy storage system that is electrically autonomous and that is completely based on renewable energies.

[0075] The multi-hybrid house energy storage system makes it possible that the electrical energy generated by a photovoltaic (PV) system, a small wind power plant or the like is distributed as required to the entire year. The system acts as an island system independent of the electrical network. Rather, the system is to ensure the electrical autarchy of the house, so that no electrical energy has to be drawn from the power grid over the entire year.

[0076] The primary task of the house power system is to make available the recovered electrical energy from photovoltaic (PV) modules or the like to the consumer in the household. Secondary, electrical energy excesses can be temporarily stored in a battery short-term storage device at times of low load or high irradiation. Tertiary, the electrical energy can be medium to long-term stored in the hydrogen long-term storage as gaseous hydrogen for times of low irradiation such as night, winter or the like, and can be needs-based made available again at any time by means of a fuel cell.

[0077] Besides to energy-related tasks, the system also functions as a controlled living room ventilation by means of a built-in ventilation device.

[0078] The hydrogen produced in the electrolysis device flows via the hydrogen line into the outwardly provided pressure storage system comprising the pressure storage device 31.

[0079] In the event of a lack of or insufficient PV energy, energy is supplied from the battery to cover the consumer load. If the energy stored in the short-term storage device is not sufficient, the fuel cell device can satisfy the additional electrical energy requirement. In the fuel cell operation, the hydrogen flows from the pressure storage device 31 to the fuel cell device via the hydrogen line.

[0080] The simultaneous operation of the fuel line device and the electrolysis device is excluded. The entire system is operated centrally via an energy manager with predictive energy management.

[0081] In principle, the second subsystem 30 is provided for operation in the outer region, but can also be erected and operated within a special region of the house under certain conditions.

[0082] The method according to the invention, which will now be explained in more detail, provides that the hydrogen is stored in the pressure storage device 31 as a function of a dynamic reference temperature with a calendric dependency. For this purpose, the energy system 10 comprises the control device 50, which is connected at least temporarily to the temperature measuring device 52 via interface 51.

[0083] The pressure in the pressure storage device 31 varies as a function of the storage temperature. The temperature-related increase in pressure behaves proportionally. The pressure storage device 31 and the high-pressure-conducting components in its periphery have an operating pressure which must not be exceeded. For example, this may be an operating pressure of 300 bar. This operating pressure is a so-called static operating pressure and is defined by the manufacturer of the pressure storage device 31. The pressure storage device 31 is designed and admitted for the maximum storage of medium up to this static operating pressure.

[0084] As a result of the temperature dependency of the storage pressure in the pressure storage device 31, it can happen without safety measures that there is a corresponding overpressure in the pressure storage device due to daily and/or seasonal temperature changes, so that the pressure storage device 31 gets damaged, in the worst case even destroyed. Or, temperature changes in the pressure storage device 31 result in the situation that the hydrogen is stored below the nominal pressure, so that capacities of the pressure storage device 31 remain unused.

[0085] According to the invention, the storage of the hydrogen in the pressure storage device 31 is now controlled on the basis of dynamic reference temperatures T.sub.ref with calendric dependency. Overpressures due to high temperatures are avoided in this case. At the same time, the nominal pressure for the storage application is maximally utilized. In order to carry out the method, the comparison file shown in FIG. 2, which is preferably a comparison table 55, comes to use.

[0086] The method according to the invention provides that, in particular in the control device 50, a dynamic operating pressure dependent on the temperature is determined, up to which the hydrogen can be stored in the pressure storage device 31. In this case, the dynamic operating pressure is determined on the basis of dynamic reference temperature values T.sub.ref with time-related dependency. Thus, a pressure exceeding, for example in summer, is avoided. After the summer, a dynamic reduction of the reference temperature leads to an increase in the calculated maximum storage pressure. A corresponding subsequent storage after the summer is thus possible. In the consumption time, for example during autumn/winter, the pressure storage device 31 is maximally loaded or used.

[0087] It is preferably provided that the dynamic operating pressure is determined in that, during the course of the method, at two or more time values, which are determined in particular, a reference temperature value T.sub.ref is determined at each time value. At each time value, the operating pressure is determined on the basis of the determined reference temperature values, for example calculated, in particular modified and/or adjusted and/or adapted.

[0088] For example, a number of reference time values 57 can be stored in the comparison table 55, wherein a reference temperature value T.sub.ref is assigned to each reference time value 57. In the upper row of the comparison table 55, the reference time values 57 can be found. In the example table, this are calendar reference time values 57 in the form of months or a number of months. In the example, a first reference time value includes the time period from January to August. A second reference time value includes the month September. A third reference time value includes the month October, while a fourth reference time value includes the time period of November and December. In the comparison table, a corresponding reference temperature value T.sub.ref is assigned to each reference time value, wherein the reference temperature values can be found in a second row of the comparison table 55. The comparison table shown is purely exemplary in nature and serves to explain the method according to the invention. The comparison table 55 can be determined or configured in any complex manner.

[0089] The time values considered, for example determined, in the course of the method are compared with the reference time values 57 in the comparison table 55. Upon a match of a time value with a reference time value 57, the dynamic operating pressure is determined, for example calculated, in particular changed and/or adjusted and/or adapted, on the basis of the reference temperature value T.sub.ref being assigned to the corresponding reference time value 57.

[0090] This can be carried out, for example, by the formula

P.sub.dyn=P.sub.stat×(T.sub.amb/T.sub.ref)

and is explained in the following by way of an example.

[0091] It is assumed, that the static operating pressure P.sub.stat was set by the manufacturer of the pressure storage device 31 to 300 bar. The point in time at which the dynamic operating pressure is to be calculated is to be in the “Jan-Aug” time period. A reference temperature value T.sub.ref of 35° C. then applies for this period of time. It is assumed that, at the point of time of the determination of the dynamic operating pressure P.sub.dyn, an ambient temperature T.sub.amb of the pressure storage device 31 of 15° C. is measured by the temperature measuring device 52. The basis for the calculation according to the above formula is temperatures which are determined in Kelvin, i.e. 273.15 K+T.sub.amb (° C.), or 273.15 K+T.sub.ref (° C.) respectively. For the example, the ambient temperature T.sub.amb is then 288.15 K, while the reference temperature T.sub.ref is 308.15 K. The dynamic operating pressure P.sub.dyn calculated according to the above formula is then 280.5 bar. Since the temperature in the considered reference time value “Jan-Aug” can change greatly and can also exceed the measured 15° C. the pressure storage device 31 is filled only up to this calculated dynamic operating pressure of 280.5 bar, in order to avoid overpressure at other times with higher temperatures. If it were found in the calculation that dynamic operating pressures of higher than 300 bar were possible, the filling would nevertheless be terminated at the fixed static operating pressure of 300 bar.

[0092] After determination of the dynamic operating pressure, which in particular is performed in the data processing device 53 of control device 50, the hydrogen is stored into the pressure storage device 31 maximally up to the dynamic operating pressure. Monitoring, that the dynamic operating pressure is thereby not exceeded, is carried out by means of the control device 50. For this purpose, the control device 53 is in communication connection, for example, with the compressor device 34 shown in FIG. 1, and can, when the dynamic operating pressure is reached, send a corresponding control signal to compressor device 34, so that the latter ceases to store further medium into the pressure storage device 31.

LIST OF REFERENCE NUMERALS

[0093] 10 Energy system (house energy system) [0094] 20 First subsystem (inner system) [0095] 21 First energy source device (electrolysis device) [0096] 22 First energy sink device (fuel cell device) [0097] 23 Valve device [0098] 24 Valve device [0099] 30 Second subsystem (outer system) [0100] 31 Pressure storage device (second energy source device) [0101] 32 Second energy sink device (medium-pressure storage device) [0102] 33 Check valve device [0103] 34 Compressor device [0104] 35 Valve device [0105] 36 Expansion device (pressure reducer) [0106] 37 Flow limiting device (capillary tube) [0107] 40 Connecting line device [0108] 40a Bidirectional line section [0109] 41 First side of the bidirectional line section [0110] 42 Second side of the bidirectional line section [0111] 50 Control device [0112] 51 Interface [0113] 52 Temperature measuring device for measuring the ambient temperature [0114] 53 Data processing device [0115] 54 Storage device [0116] 55 Comparison table [0117] 56 Data exchange connection [0118] 57 Reference time value