Method for operating a tank system

Abstract

The present invention relates to a method (100) for operating a tank system (200). The proposed method (100) comprises: - determining (101) a tank temperature in a pressure tank (201) of the tank system (200), - determining (103) an ambient temperature in the environment of the pressure tank (201), - comparing (105) the determined tank temperature with a predefined threshold value, and - outputting (107) a limited maximum permissible mass-flow rate from the pressure tank (201) if the determined tank temperature is lower than the threshold value, wherein the limited maximum permissible mass-flow rate from the pressure tank (201) is selected depending on the determined tank temperature and the determined ambient temperature.

Description

[0001] Description

[0002] title

[0003] Method for operating a tank system

[0004] The presented invention relates to a method for operating a tank system, a tank system and an energy converter.

[0005] State of the art

[0006] In pressure tanks, a reduction in the tank contents, e.g., through the withdrawal of a gas mass from a pressure tank by a consumer, leads to a cooling in the pressure tank.

[0007] A drop in the temperature of a pressure tank below a permissible minimum temperature can damage components of the pressure tank or the tank system encompassing the pressure tank. Therefore, functions are known that close the pressure tank valves when the temperature of a pressure tank reaches a predetermined permissible minimum temperature, thus preventing a further reduction in the pressure tank's temperature.

[0008] Closing the tank valves of the pressure tank can lead to situations where a consumer supplied with fuel by the pressure tank is undersupplied and may be damaged.

[0009] Disclosure of the invention

[0010] Within the scope of the presented invention, a method for operating a tank system, a tank system, and an energy converter are introduced. Further features and details of the invention will become apparent from the respective dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the tank system and the energy converter according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.

[0011] The presented invention serves in particular to provide a possibility for the robust operation of a consumer supplied with fuel by a tank system.

[0012] Thus, according to a first aspect of the presented invention, a method for operating a tank system is presented.

[0013] The presented method comprises determining a tank temperature in a pressure tank of the tank system, determining an ambient temperature in the environment of the pressure tank, comparing the determined tank temperature with a predetermined threshold value, and outputting a limited maximum permissible mass flow rate from the pressure tank if the determined tank temperature is less than the threshold value, wherein the limited maximum permissible mass flow rate from the pressure tank is selected depending on the determined tank temperature and the determined ambient temperature.

[0014] In the context of the presented invention, a tank temperature is to be understood as the temperature of a pressure tank, in particular the temperature of a medium stored in a pressure tank, such as a gas temperature and / or the temperature of a structure forming the pressure tank.

[0015] In the context of the presented invention, "outputting a determined limited maximum permissible mass flow from a pressure tank" means displaying a value of the limited maximum permissible mass flow, storing a value of the limited maximum permissible mass flow in a memory, and / or transmitting a value of the limited maximum permissible mass flow to a receiver, such as a consumer system. Accordingly, the limited maximum permissible mass flow preferably serves as a control variable for adjusting the mass flow from a pressure tank to a consumer system.

[0016] The presented method is particularly suitable for supplying a consumer system, such as a fuel cell system or a hydrogen engine, with hydrogen while adhering to specified temperature limits of a pressure tank for storing the hydrogen.

[0017] Naturally, the presented method or invention can be applied not only to a single pressure tank, but also to a multitude of pressure tanks in a tank system. In this case, for example, each pressure tank in the multitude can be individually checked and its mass flow adjusted.

[0018] The presented method is based on a dynamic determination of a maximum permissible mass flow rate of, for example, fuel that can be extracted from a pressure tank in the event that the pressure tank or a fluid stored in the pressure tank has a temperature that could lead to damage to the tank system.

[0019] To determine whether the pressure tank or a fluid stored in the pressure tank has a temperature that could lead to damage to the tank system, the tank temperature of the pressure tank is determined, i.e., measured using a temperature sensor or calculated using a mathematical model, e.g., based on values ​​obtained from a pressure sensor located on the pressure tank.

[0020] By comparing the determined tank temperature with a predefined threshold value, which is stored, for example, in a memory of the tank system, it is determined whether a mass flow currently flowing out of the pressure tank causes the pressure tank to cool down to such an extent that the pressure tank or a fluid stored in the pressure tank has a temperature that could lead to damage to the tank system.

[0021] Accordingly, if the determined tank temperature is less than or equal to the threshold value, a limited maximum permissible mass flow from the pressure tank is determined and output.

[0022] According to the invention, the determination of the limited maximum permissible mass flow rate depends on the determined tank temperature and the determined ambient temperature.

[0023] It may be provided that the limited maximum permissible mass flow is selected such that, when a mass flow flows out of the pressure tank, the tank temperature is always greater than or equal to a specified minimum temperature value for a permissible minimum temperature of the pressure tank.

[0024] By selecting a limited maximum permissible mass flow rate such that, when a mass flow is released from the pressure tank, the tank temperature is always greater than or equal to a specified minimum temperature value for a permissible minimum temperature of the pressure tank, thermal damage to the tank system and / or a consumer system is reliably avoided.

[0025] In particular, it may be provided that if the tank temperature is lower than a minimum permissible tank temperature, the limited maximum permissible mass flow rate is selected as "0", so that no medium flows out of the pressure tank.

[0026] It may also be provided that the threshold is higher than the permissible minimum temperature.

[0027] It may also be provided that the limited maximum permissible mass flow is selected in such a way that a decrease in thermal energy in the pressure tank due to the mass flow flowing out of the pressure tank is less than or equal to a heat input from the environment into the pressure tank.

[0028] Determining the input of thermal energy from the environment into the pressure tank can be done using a first temperature difference between the tank temperature and an ambient temperature in the vicinity of the pressure tank, or using a second temperature difference between the ambient temperature in the vicinity of the pressure tank and the threshold value.

[0029] To determine the input of thermal energy from the environment into the pressure tank, the ambient temperature can be measured, for example, using a temperature sensor and / or calculated using a mathematical model, for example, based on heat energy radiated by the consumer.

[0030] In particular, by comparing the ambient temperature with a reference value, such as a specified threshold, a measure can be determined by which the cooling of the pressure tank due to the ambient temperature can be compensated. Based on this measure, the limited maximum permissible mass flow rate can be determined, for example, using an allocation scheme.

[0031] It may also be provided that the limited maximum permissible mass flow is determined on the basis of an input of thermal energy from the environment into the pressure tank, wherein the input of thermal energy from the environment into the pressure tank is determined on the basis of a first temperature difference between the tank temperature and an ambient temperature in the vicinity of the pressure tank or on the basis of a second temperature difference between the ambient temperature in the vicinity of the pressure tank and the threshold value.

[0032] It may also be provided that the determination of the limited maximum permissible mass flow from the pressure tank is carried out using a characteristic map that extends over a tank temperature and an ambient temperature, or that the determination of the limited maximum permissible mass flow from the pressure tank is carried out using a characteristic map that extends over a tank temperature and a difference temperature between an ambient temperature and a permissible minimum temperature of the pressure tank.

[0033] Using a characteristic map, a corresponding limited maximum permissible mass flow can be quickly and accurately assigned to the current state of a tank system, which is determined based on a current ambient temperature and a current tank temperature.

[0034] It may also be provided that the limited maximum permissible mass flow from the pressure tank is additionally selected depending on the current speed of a vehicle encompassing the tank system.

[0035] Since the speed of a vehicle encompassing the tank system affects the tank temperature due to a corresponding airflow, a particularly precise limited maximum permissible mass flow can be determined by taking the speed of a vehicle encompassing the tank system into account.

[0036] It may also be provided that the determination of the tank temperature, in particular of an input of thermal energy from the environment into the pressure tank, is carried out taking into account at least one flow characteristic that quantifies the thermal properties of an airflow around the pressure tank.

[0037] An airflow around the pressure tank, provided, for example, by a vehicle's airflow and / or a blower, has a significant influence on the tank's thermal behavior. Accordingly, such an airflow can be assigned a flow coefficient, for example, using a mapping scheme. This flow coefficient can then be used, for instance, as a coefficient when determining the maximum permissible mass flow rate. Furthermore, the limited maximum permissible mass flow rate from the pressure tank can also be selected based on the pressure within the tank.

[0038] Since pressure in the pressure tank directly affects the tank temperature, a particularly precise limited maximum permissible mass flow rate can be determined by taking the pressure in the pressure tank into account.

[0039] By determining the tank temperature as a function of the pressure applied in the pressure tank, which is measured, for example, by means of a pressure sensor arranged on the pressure tank, a temperature sensor on the pressure tank can be dispensed with.

[0040] It may also be provided that the limited maximum permissible mass flow from the pressure tank is additionally selected depending on at least one tank characteristic number, whereby the tank characteristic number quantifies thermal properties of the pressure tank.

[0041] A tank characteristic value, which quantifies the thermal properties of the pressure tank, can be determined, for example, based on its size, shape, and / or material properties, in particular the thermal conductivity of the material forming the pressure tank. The tank characteristic value can, for example, be considered as a coefficient when determining the maximum permissible mass flow rate.

[0042] It may also be provided that the limited maximum permissible mass flow rate is specified as an average mass flow rate over a given time range.

[0043] For example, the time range can be selected to allow fluctuations in the mass flow rate. Accordingly, a briefly increased mass flow rate from the pressure tank is permissible, provided that operation with a lower mass flow rate subsequently occurs within the same time range. Changing the mass flow rate enables an optimized operating strategy for the fuel cell system, particularly when supplying it.

[0044] It may also be provided that the determined limited maximum permissible mass flow is output to a consumer system.

[0045] To output the limited maximum permissible mass flow to a consumer system, the limited maximum permissible mass flow can be transmitted to the consumer system, for example, via a communication interface, such as a cable or a wireless connection, between the tank system and the consumer system.

[0046] It may also be provided that a mass flow conveyed from the tank system by the consumer system is adjusted to the limited maximum permissible mass flow.

[0047] By using the determined limited maximum permissible mass flow rate, a mass flow rate pumped from the tank system can be adjusted, for example, by adjusting a dosing quantity of a consumer system.

[0048] Alternatively, by adjusting a consumer system, e.g. by means of a metering valve or a pressure regulator in a supply line, the mass flow from the pressure tank can be effectively limited.

[0049] According to a second aspect, the presented invention relates to a tank system for storing a fluid.

[0050] The presented tank system comprises a number of pressure tanks and a computing unit, the computing unit being configured to carry out one possible embodiment of the presented method.

[0051] Due to the presented method, the presented tank system enables a continuous supply of fluid to a consumer system from its pressure tanks. According to a third aspect, the presented invention relates to an energy converter for converting energy.

[0052] The presented energy converter comprises a consumer system, a tank system and a computing unit.

[0053] The computing unit is configured to execute one possible implementation of the presented procedure.

[0054] Due to the presented method, the presented tank system enables a continuous supply of fluid from its pressure tanks to the consumer system of the presented energy converter.

[0055] Advantages described in detail for the method of operating a tank system according to the first aspect of the invention apply equally to the tank system according to the second aspect of the presented invention and to the energy converter according to the third aspect of the presented invention, and vice versa.

[0056] Further advantages, features, and details of the presented invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0057] Drawings

[0058] They each show schematically:

[0059] Figure 1 shows a possible embodiment of the presented method and

[0060] Figure 2 shows a possible embodiment of the presented energy converter with a possible embodiment of the presented tank system. Description of the exemplary embodiments.

[0061] Fig. 1 shows a method 100 for operating a tank system 200.

[0062] The procedure 100 comprises a first determination step 101, in which a tank temperature in a pressure tank 201 of the tank system 200 is determined, a second determination step 103, in which ambient temperature in an environment of the pressure tank 201 is determined, a comparison step 105, in which the determined tank temperature is compared with a predetermined threshold value, and an output step 107, in which a maximum permissible mass flow from the pressure tank 201 is output if the determined tank temperature is less than the threshold value.

[0063] The limited maximum permissible mass flow from the pressure tank 201 is selected depending on the determined tank temperature and the determined ambient temperature.

[0064] Figure 2 shows an energy converter 300 for converting energy.

[0065] The energy converter 300 comprises a consumer system 301, a tank system 200, and a computing unit 303. The computing unit 203 is configured to execute the process 100 according to Fig. 1. For this purpose, the computing unit 203 can, for example, adjust a metering system for dosing hydrogen into the consumer system 301 such that the maximum permissible mass flow rate is set at each pressure tank 201 of the tank system 200.

[0066] Alternatively, a computing unit 203 of the tank system 200 can adjust a tank valve 205 of the pressure tank 201 such that the maximum permissible mass flow rate is set at the pressure tank 201.

Claims

Claims 1. Method (100) for operating a tank system (200), the procedure (100) comprises: Determining (101) a tank temperature in a pressure tank (201) of the tank system (200), Determining (103) an ambient temperature in an environment of the pressure tank (201), Comparing (105) the determined tank temperature with a predetermined threshold value, and Dispensing (107) a limited maximum permissible mass flow from the pressure tank (201), in the event that the determined tank temperature is less than the threshold value, wherein the limited maximum permissible mass flow from the pressure tank (201) is selected depending on the determined tank temperature and the determined ambient temperature.

2. Method (100) according to claim 1, characterized by that the limited maximum permissible mass flow is selected such that when a mass flow is discharged from the pressure tank (201), the tank temperature is always greater than or equal to a specified minimum temperature value for a permissible minimum temperature of the pressure tank (201).

3. Method (100) according to claim 2, characterized by that the threshold is greater than the permissible minimum temperature.

4. Method (100) according to one of the preceding claims, characterized in that that the limited maximum permissible mass flow rate is selected such that a decrease in thermal energy in the pressure tank (201) due to the mass flow rate flowing out of the pressure tank (201) is less than or equal to a heat input from the environment into the pressure tank (201).

5. Method (100) according to one of the preceding claims, characterized in that that the limited maximum permissible mass flow rate is determined based on an input of thermal energy from the environment into the pressure tank (201), wherein the input of thermal energy from the environment into the pressure tank (201) is determined on the basis of a first temperature difference between the tank temperature and an ambient temperature in the vicinity of the pressure tank (201) or on the basis of a second temperature difference between the ambient temperature in the vicinity of the pressure tank (201) and the threshold value.

6. Method (100) according to one of the preceding claims, characterized in that that the determination of the limited maximum permissible mass flow from the pressure tank (201) is carried out using a characteristic map that extends over a tank temperature and an ambient temperature or that the determination of the limited maximum permissible mass flow from the pressure tank (201) is carried out using a characteristic map that extends over a tank temperature and a difference temperature between an ambient temperature and a permissible minimum temperature of the pressure tank (201).

7. Method (100) according to any one of the preceding claims, characterized by that the limited maximum permissible mass flow from the The pressure tank (201) is additionally selected depending on the current speed of a vehicle encompassing the tank system.

8. Method (100) according to any one of the preceding claims, characterized by that the limited maximum permissible mass flow from the The pressure tank (201) is additionally selected depending on the pressure in the pressure tank (201).

9. Method (100) according to any one of the preceding claims, characterized by that the limited maximum permissible mass flow from the The pressure tank (201) is additionally selected depending on at least one tank identifier, where the tank identifier quantifies the thermal properties of the pressure tank (201).

10. Method (100) according to any one of the preceding claims, characterized by that the limited maximum permissible mass flow rate is specified as the average mass flow rate over a given time range.

11. Method (100) according to any one of the preceding claims, characterized by that the determined limited maximum permissible mass flow is output to a consumer system (301).

12. Method (100) according to claim 11 , characterized by that a mass flow conveyed from the tank system (200) by the consumer system (301) is adjusted to the limited maximum permissible mass flow.

13. Tank system (200) for storing a fluid, the tank system (200) includes: a number of pressure tanks (201) and a computing unit (203), wherein the computing unit (203) is configured to perform a method (100) according to any one of claims 1 to 12.

14. Energy converter (300) for converting energy, the energy converter (300) comprises: - a consumer system (301), a tank system (200) and a computing unit (203), wherein the computing unit (203) is configured to execute a method (100) according to one of claims 11 or 12.

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