Method and apparatus for controlling energy exchange between multiple energy systems

Abstract

The invention relates to a method for controlling an energy exchange between a plurality of energy systems via an electrical network, said control being carried out by means of a control device that is central with respect to the energy systems, at least one of the energy systems comprising a thermal energy generating device that converts electrical energy from the electrical network into thermal energy. The method is characterized by the following steps: (S1) providing an electrical load prediction # imgabs1 # of the thermal energy generating plant for covering the set thermal load # imgabs0 #; -(S2) transmitting the provided electrical load predictions # imgabs2 to the control device, to which the other energy systems likewise transmit the respective electrical load predictions; -(S3) the control device determines the electrical power # imgabs4 # belonging to the energy exchange on the basis of the transmitted set electrical load prediction # imgabs3 #, the determination being carried out by means of an optimization method by means of a minimization of an associated objective function, and the objective function being designed to determine the electrical power # imgabs4 # belonging to the energy exchange; minimizing the number of times of startup # imgabs6 # of the thermal energy generation device for covering the set thermal load # imgabs5 #; and-(S4) controlling the energy exchange by means of the control device as a function of the determined electrical power # imgabs7 #. The invention further relates to a control device for carrying out the method.

Description

Technical Field

[0001] The invention relates to a method according to the preamble of claim 1 and to a device according to the preamble of claim 10 . Background Art

[0002] Energy systems such as urban areas, municipalities, buildings, industrial facilities, etc. usually include various energy technology devices, such as power generation devices, power consumption devices and / or storage devices. The most efficient distribution of the energy generated and consumed in the entire system via the associated power distribution network (grid) and the exchange of energy are technical challenges that can be solved, for example, with the help of local energy markets. In this case, the local energy market is technically formed by a control device central to the energy system, which is used to control the energy exchange.

[0003] Such a control device is known, for example, from document EP 3518369 A1.

[0004] However, the local energy market is in principle oriented towards the electricity network (grid). Here, the thermal energy aspect of the energy system of, for example, a residential building is usually not explicitly taken into account. On the other hand, thermal energy accounts for about 70% of the energy demand of an average household. In principle, the demand for electrical energy for generating thermal energy can also be handled on the local energy market. However, thermal energy generating devices for generating thermal energy will thus be considered within the scope of the local energy market like ordinary electrical devices. Here again, specific technical requirements for thermal energy generating devices are not taken into account. Summary of the invention

[0005] The object of the present invention is to integrate the provision of thermal energy by a thermal energy generating plant into the local energy market in an improved manner.

[0006] This object is achieved by a method having the features of independent claim 1 and by a control device having the features of independent claim 10. Advantageous embodiments and developments are given in the dependent claims.

[0007] The method according to the invention for controlling the exchange of energy between a plurality of energy systems via an electrical network, the control being carried out by means of a control device central to the energy systems, wherein at least one of the energy systems comprises a thermal energy generating plant which converts electrical energy from the electrical network into thermal energy, is characterized by at least the following steps:

[0008] - Provides for overriding the set heat load Electric load forecast of the thermal energy generating equipment ;

[0009] - Provide the electricity load forecast transmitting to the control device, wherein the other energy systems also transmit respective electrical load forecasts to the control device;

[0010] - The control device is based on the transmitted set electrical load forecast Determine the electrical power that belongs to the energy exchange (target value), wherein the determination is performed by an optimization method by minimizing an associated target function, and the target function is designed such that the set thermal load is covered The number of startups of the heat generating equipment Minimize; and

[0011] - With the aid of the control device, the electric power To control energy exchange.

[0012] The method according to the invention and / or one or more functions, features and / or steps of the method according to the invention and / or one of its designs can be computer-supported. In particular, the control device comprises one or more computing units which are designed and configured to numerically execute the optimization method, for example by means of instructions, and to determine the electrical power or target power associated with the energy exchange.

[0013] Especially in terms of structure, the IPCC Fifth Assessment Report defines an energy system as: “all the components involved in the generation, conversion, supply and use of energy” (Annex I, p. 1261).

[0014] Energy systems usually include multiple components, in particular energy technology equipment, such as energy conversion equipment, electrical equipment and / or storage equipment. Here, the energy system can generate and / or provide energy in multiple forms (multimodal energy system). In particular, such an energy system can provide one or more forms of energy for electrical equipment, such as buildings or residential buildings, industrial equipment or private equipment, wherein the provision is carried out in particular by converting various forms of energy, by transmitting various forms of energy and / or by storing various forms of energy. In other words, various forms of energy, such as heat energy, cold energy or electrical energy, are coupled in terms of their generation, their provision and / or their storage by means of a multimodal energy system. The energy system is, for example, a building, in particular a residential building and / or an office building and / or an industrial equipment.

[0015] As energy technology equipment, an energy system can include one or more of the following components: generators, combined heat and power plants, in particular district heating power plants (blockheizkraftwerke), gas boilers, diesel generators, heat pumps, compression refrigerators, absorption refrigerators, pumps, district heating networks, energy transmission lines, wind turbines or wind power plants, photovoltaic systems, energy storage devices, in particular battery storage devices, biomass plants, biogas plants, waste incineration plants, industrial plants, conventional power plants and / or similar equipment.

[0016] The method is therefore based on a plurality of energy systems, for example buildings, which exchange energy via an electrical network. In this case, the energy systems can feed power into the electrical network and / or draw power from the electrical network at specific times. By feeding power into the electrical network and / or drawing power from the electrical network within a specific time range, a specific energy or amount of energy is exchanged between the energy systems, that is, energy is exchanged between the energy systems. At least one of the energy systems comprises a thermal energy generation device, which draws electrical energy for providing or for covering a thermal energy demand.

[0017] The energy exchange between the energy systems is controlled by means of a central control device for the energy systems. Here, the control is carried out by means of a control device configured to perform the optimization method. Preferably, a local energy market is formed by the central control device.

[0018] Optimization methods within the meaning of the invention are numerical methods in which target values ​​for the power that forms the basis for the energy exchange are determined. In this case, the power or power value mentioned is a variable of a determined target function that is minimized or maximized within the scope of the optimization method. Minimization can always be converted into maximization by means of corresponding signs.

[0019] In other words, the minimum or maximum value of the objective function determines the time-dependent power or its target value for the control. In this case, the objective function usually models the technical goals that are tracked for the energy exchange (e.g. the best possible matching of power generation and power consumption, the lowest possible CO2 emissions or the highest possible energy conversion rate). In this case, the objective function is minimized and is designed so that the number of starts of the heat generation plant required to cover the heat demand (if necessary, when using the flexibility of the heat generation) is minimized. In this case, the term "flexibility" refers to the temporal mobility of the heat generation.

[0020] According to a first step of the method according to the invention, a method for covering the set heat load is provided. Electrical load forecasting for thermal energy generating equipment The electrical load forecast provided here indicates at what point in time the thermal energy generating installation needs to draw what electrical power from the grid in order to cover the set time-dependent thermal load. In the case of a local energy market, the electrical load forecast can correspond to the maximum (time-dependent) power that the energy system is intended to draw to cover the thermal load. The provision of the electrical load forecast can be determined, for example, by a forecast module within the energy system.

[0021] For example, if the thermal system of a household includes a thermal energy storage and a thermal energy generating device, such as a heat pump and / or an electric boiler, which generates thermal energy from electricity, thus coupling the thermal and electrical energy sectors, then the thermal energy demand of the household and the electricity required for this purpose can also be obtained in an optimal manner on the local energy market. For this purpose, the time profile of the thermal energy demand is determined (heat load forecast) and the electrical power requirement for operating the thermal energy generating device is determined therefrom (electrical load forecast).

[0022] In the second step of the method according to the invention, the provided electric load forecast Transmitted to the control device. In this case, the other energy systems can also transmit their respective electrical load forecasts to the control device. Therefore, the central control device knows at what time each of the energy systems should draw or feed what (maximum) power from the power grid. In this case, the control device can receive from the energy system other data / information about the energy exchange set, in particular information about the maximum connected power, about the remuneration plan for feeding and / or drawing and / or about the load that can be moved over time (flexibility). The mentioned information and the electrical load forecast and the thermal load forecast are usually related to a certain time interval, for example, the next day, in particular the next day.

[0023] According to a third step of the method according to the invention, the control device calculates the set electrical load forecast based on the transmitted Determine the electrical power that belongs to the energy exchange In this case, the determination is performed by an optimization method by minimizing the associated objective function. The objective function is designed so that the heat load to be covered is The number of startups of the heat generating equipment minimize.

[0024] Here, the objective function includes the electrical power And the number of starts The variable is used as a variable whose value is determined by minimizing the objective function. The objective function can model other technical goals (such as the lowest possible total CO2 emissions, the highest possible energy conversion rate and / or the lowest possible total cost).

[0025] By minimizing the start-up of the heat generating plant according to the invention, the set heat load is generated as effectively as possible with respect to the wear of the heat generating plant, taking into account the flexibility (the resulting mobility over time). This is because typical heat generating plants age, i.e. wear out, as the number of their starts increases. The method thus enables the operation of the heat generating plant to be optimized with respect to wear. This makes it possible to integrate the heat generating plant into the local energy market in an improved manner, since the specific technical requirements of the heat generating plant are taken into account in an improved manner.

[0026] In the fourth step of the method, the control device is used according to the determined electrical power The energy exchange is controlled by a control device. In this case, the control is usually carried out indirectly via a control device. The control device determines target values ​​for the power of each energy system (determined electrical power) by means of the optimization performed. These target values ​​are then transmitted to the corresponding energy system. Within the energy system, these target values ​​for the power are implemented by local control units and / or local regulating units, which transmit corresponding control signals to the corresponding devices, in particular thermal energy generating devices.

[0027] The present invention particularly has one or more of the following advantages:

[0028] - More efficient possibilities for regulating the supply / provision of heat generating plants, in particular heat pumps and / or electric boilers, on the local energy market.

[0029] - Utilization of the flexibility potential of thermal energy systems.

[0030] - Cost savings in the individual energy systems through optimal energy purchase and less wear.

[0031] - The possibility of selling flexibility and thus the possibility of exploiting additional power revenues for the energy system. This can be achieved, for example, if the power demand of the thermal energy generation system at the time of the feed-in increase is met by renewable energy generation in the entire system, thus resulting in low prices. In this case, the use of the flexible thermal energy supply by the thermal energy generation system (especially in the presence of thermal energy storage) provides a system service (negative regulation power) that can be paid for by the network operator accordingly.

[0032] - Improved resource management of renewable energies by utilizing the mobile potential of thermal energy storage. This can be achieved if, for example, the power demand of the thermal system observed at a time point of increased feed-in is met by renewable energy generation, the utilization of which is thus increased. Alternatively, due to grid overload, thermal energy generation equipment may be turned down, and any potential thermal energy generation during this time is lost.

[0033] - Improvement of the sustainability of the entire energy system, since the potential flexibility of thermal energy storage can be utilized. Thus, additional grid modifications are avoided without the need to install new storage systems. This can be achieved, for example, if the power demand of the thermal energy generation plant at the time of increased feed-in is met by renewable energy generation in the entire system, thus resulting in low prices. Thus, on the one hand, feed-in peaks can be intercepted. On the other hand, the electrical power of the thermal energy generation plant is reduced at times of increased power consumption, for example in the morning and / or evening, thus avoiding load peaks.

[0034] According to the present invention, a control device for controlling energy exchange between a plurality of energy systems via a power grid, wherein at least one of the energy systems comprises a thermal energy generating device for converting electrical energy from the power grid into thermal energy, is characterized in that the control device is constructed and configured to:

[0035] - Receive the heat load provided to the heat generating equipment to cover the set Electricity load forecasting , and receiving other corresponding electric load forecasts from other energy systems;

[0036] - Based on the transmitted set electrical load forecast Determine the electrical power that belongs to the energy exchange , wherein the determination is performed by an optimization method by minimizing an associated objective function, and the objective function is designed such that the heat load to be provided is covered The number of startups of the heat generating equipment minimize; and

[0037] - Based on the determined electrical power Controlling energy exchange.

[0038] The control device according to the invention has advantages and / or designs that are similar, equivalent and identical to the method according to the invention.

[0039] According to an advantageous embodiment of the invention, the thermal energy generating device is designed as a heat pump.

[0040] Advantageously, the wear of the heat pump can thereby be significantly reduced. This is because the heat pump wears, in particular, as the number of its starts or the number of compressor starts increases. The more frequently the heat pump is activated, i.e. started, the greater its degree of wear. However, in order to make the most of the flexibility of heat generation, and therefore of the operation of the heat generating device, it is usually necessary to start and shut down the heat generating device several times. In this case, heat can thus be provided or the heat load can at least be partially covered while reducing the wear associated with the temporal flexibility of the heat generation provided by the heat pump.

[0041] Alternatively or in addition, the thermal energy generating device can be designed as a hot water boiler.

[0042] In an advantageous development of the invention, the heat load prediction according to To determine the load forecast ,in, It is the performance indicator of the heat pump.

[0043] The performance indicators of the heat pump are advantageously generally known, so that the electrical load forecast can be determined in an efficient and sufficiently approximate manner via the above-mentioned relationships. The determination of the electrical load forecast can be performed by the energy system itself and / or by the control device.

[0044] According to an advantageous design of the present invention, the external temperature is collected, and the performance index is determined based on the collected external temperature. .

[0045] This makes it possible to advantageously take into account the relationship between the heat supply or heat generation and the external temperature. In particular, this is advantageous for heat pumps that use air as a heat source. The influence of the heat source can thus be taken into account.

[0046] In an advantageous development of the invention, the objective function includes a function for minimizing the number of starts. of Items of the form, where is the wear factor, and is constructed as a binary variable that represents the number of starts.

[0047] Here, the objective function may include further terms, which are minimized. The entire objective function is then minimized by the optimization method. has a first value and a second value, preferably 0 and 1, wherein its value, which is usually time-dependent, is determined by minimizing an objective function. Thus, Specify the time at which the heat generating device, in particular the heat pump, is started.

[0048] According to an advantageous embodiment of the invention, a further binary variable is used in the optimization method: and ,in, Indicates the operating status of the heat generating equipment, and Indicates the number of shutdowns of heat generating equipment and is used as an auxiliary condition in the optimization method and .

[0049] This makes it possible to improve the optimization method in an advantageous manner. In other words, the aforementioned auxiliary conditions used in the optimization method can be used to determine the start and stop of the heat generating plant, in particular the heat pump. These further binary variables can be used advantageously as auxiliary conditions in the optimization method and thus take into account further technical requirements of the heat generating plant, for example, by or As auxiliary conditions, a minimum switch-on time and / or a minimum switch-off time of the thermal energy system is used and therefore taken into account.

[0050] In an advantageous development of the invention, the energy system additionally comprises a thermal energy store which is thermally coupled to the thermal energy generating plant, wherein the target function is designed to minimize storage losses of the thermal energy store.

[0051] This can advantageously minimize the storage losses of the thermal energy storage device. To model, represents the heat load, represents the thermal loading power of the memory, represents the thermal power generated by the thermal energy generating equipment, and Indicates the thermal dissipation power of the memory.

[0052] In addition, thermal energy storage can be modeled in the following ways: .

[0053] Here, is the energy content of the memory, is the time step, is the loading efficiency, and is the emission efficiency. The loss of storage due to self-emission is given by The model can be used flexibly and provides sufficient accuracy for various storage technologies. Constant parameters, such as the mentioned efficiency, can be determined from historical measurement data. Further measurements, such as existing temperature sensors, can be used to estimate the energy content of the storage.

[0054] The losses due to self-emission are simplified by To describe, where the loss coefficient It can be estimated from historical measurement data.

[0055] The maximum and minimum storage capacity as well as the maximum loading (or charging) and discharge (or discharging) powers can be estimated from system parameters, such as the maximum and minimum inlet and return water temperatures and the parameters of the connecting lines. These system parameters limit the corresponding parameters in the following way: as well as These auxiliary conditions can be used in the optimization method.

[0056] According to an advantageous design of the present invention, the objective function includes a Items of the form, where is the heat weighting factor.

[0057] This makes it possible to advantageously take into account and minimize the storage losses during the optimization process. Therefore, it is particularly preferred that the objective function includes the term , so that it is minimized. Here, you can set additional multiplicative numerical constants, such as the time step of the optimization In addition, wear and storage losses are accounted for differently through their respective weighting factors Alternatively or in addition, the two terms can also be divided by corresponding proportional factors so that they are in the same numerical order of magnitude. This advantageously improves the numerical analysis.

[0058] Therefore, the solution to the optimization problem mentioned above includes the optimal trajectories for the power consumption of the thermal energy generating device, in particular the heat pump, the loading (or charging) state of the storage, the loading (or charging) and the discharge (or discharging) of the storage, with the wear of the thermal energy generating device being as low as possible.

[0059] In an advantageous development of the invention, further auxiliary conditions are used in the optimization method: ,in, is the minimum switch-on power, and It is the rated power of the heat generating equipment.

[0060] Thus, the technical performance limits of the thermal energy generation system are advantageously taken into account in the optimization method. In other words, an optimization result that complies with the technical performance limits of the thermal energy generation system can be determined thereby. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Further advantages, features and details of the invention are apparent from the exemplary embodiments described below and from the accompanying drawings.

[0062] Figure 1 A flow chart of a method according to one design solution of the present invention is schematically shown.

[0063] Similar, equivalent or identically functioning elements may have the same reference signs in the figures. DETAILED DESCRIPTION

[0064] The present embodiment is based on a building (energy system) which comprises a heat pump for at least partially covering the thermal energy demand of the building. Furthermore, the energy system may comprise an energy storage, for example a water storage, thermally coupled to the heat pump.

[0065] For this energy system, a heat load forecast for a period of time in the future can be determined. Based on the determined heat load forecast, for example, an electrical load forecast for the heat pump can be determined by a performance indicator (Leistungszahl) of the heat pump. In this case, thermal energy storage can be taken into account. The electrical load forecast thus determined can be met by a corresponding supply on the local energy market. In this case, the local energy market is formed by a central control device for a plurality of energy systems, which controls the energy exchange between the energy systems. For this purpose, the control device determines a time-dependent target power for each energy system by means of a numerical optimization method.

[0066] According to the first step S1 of the method, an electrical load forecast for a heat pump is therefore determined for at least partially covering the provided thermal load. It is thus known at what point in time which electrical power must be drawn from the grid in order to cover the corresponding thermal load.

[0067] In the second step S2 of the method, the provided electricity load forecast is transmitted to the control device of the local energy market. In this case, all energy systems participating in the local energy market also transmit their electricity load forecasts to the control device. The control device then adapts these electricity load forecasts as best as possible with respect to the target function by means of an optimization method.

[0068] According to a third step S3, the control device determines the electrical power associated with the energy exchange based on the transmitted set electrical load forecast, wherein the determination is performed by an optimization method by minimizing the associated objective function. In this case, the objective function is designed or stored such that at least the number of heat pump starts for covering the set thermal load is minimized. This advantageously reduces the wear on the heat pump, but still allows the time flexibility of the heat energy generated by the heat pump (which usually increases the number of starts) to be utilized and the thermal load to be covered as optimally as possible.

[0069] Finally, in a fourth step S4 of the method, the electric power or target power determined by the optimization method is implemented. In other words, the energy exchange is controlled by means of the control device according to the determined electric power. Thus, energy is exchanged between the energy systems via the power grid.

[0070] Although the present invention has been further shown and described in detail by preferred embodiments, the present invention is not limited to the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of protection of the present invention.

[0071] Reference numerals list

[0072] S1 First step

[0073] S2 Second step

[0074] S3 Step 3

[0075] S4 Step 4

Claims

1. A method for controlling the exchange of energy between a plurality of energy systems via a power grid, the control being carried out by means of a central control device for the energy systems, wherein: At least one of the energy systems comprises a thermal energy generating device for converting electrical energy from the grid into thermal energy, characterized by the following steps: - (S1) Provides for covering the set heat load Electric load forecasting of the thermal energy generating equipment ; - (S2) Provide the electricity load forecast transmitting to the control device, wherein the other energy systems also transmit respective electrical load forecasts to the control device; - (S3) the control device predicts the set electric load based on the transmitted Determine the electrical power attributed to energy exchange , wherein the determination is performed by an optimization method by minimizing an associated objective function, and the objective function is designed such that the heat load to be provided is covered The number of startups of the thermal energy generating equipment Minimize; and - (S4) using the control device according to the determined electrical power To control energy exchange.

2. The method according to claim 1, characterized in that: The thermal energy generating device is designed as a heat pump.

3. The method according to claim 2, characterized in that Prediction by heat load according to To determine the electrical load forecast ,in, It is the performance index of the heat pump.

4. The method according to claim 3, characterized in that Collect external temperature and determine performance indicators based on the collected external temperature .

5. The method according to any one of the preceding claims, characterized in that The objective function includes a function for minimizing the number of startups of Items of the form, where is the wear factor, and is constructed as a binary variable, which represents the number of starts.

6. The method according to claim 5, characterized in that Use of additional binary variables in the optimization method and ,in, indicates the operating status of the thermal energy generating device, and represents the number of shutdown times of the thermal energy generating device, and an auxiliary condition is used in the optimization method and .

7. The method according to any one of the preceding claims, characterized in that The energy system additionally comprises a thermal energy store which is thermally coupled to the thermal energy generating plant, wherein the target function is designed to minimize storage losses of the thermal energy store.

8. The method according to claim 7, characterized in that The objective function includes the function for minimizing the storage loss Items of the form, where is the heat weighting factor.

9. The method according to any one of the preceding claims, characterized in that Use of additional auxiliary conditions in the optimization method ,in, is the minimum switch-on power, and is the rated power of the thermal energy generating device.

10. A control device for controlling energy exchange between a plurality of energy systems via a power grid, wherein: At least one of the energy systems comprises a thermal energy generating device for converting electrical energy from the power grid into thermal energy, wherein the control device is constructed and configured to: - receiving a heat load provided to the heat generating device to cover the set heat load Electricity load forecasting , and receiving other corresponding electric load forecasts from other energy systems; - Based on the transmitted set electrical load forecast Determine the electrical power attributed to energy exchange , wherein the determination is performed by an optimization method by minimizing an associated objective function, and the objective function is designed such that the heat load to be provided is covered The number of startups of the thermal energy generating equipment minimize; and - Based on the determined electrical power Controlling energy exchange.

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