CN216390511U - Control unit for a system and building energy system - Google Patents

Abstract

A control unit (100) is proposed for a system having an air conditioning system (10), a photovoltaic system (20) for generating electrical energy and an energy store (30) for storing electrical energy, said system being connected to a network connection point and being suitable for feeding electrical energy into an external power grid (60) or for absorbing electrical energy therefrom. The control unit is configured to control the air conditioning device (10), the photovoltaic device (20) and the energy storage (30) jointly as a function of at least one condition of amperage and/or voltage related to the fed or absorbed electrical energy. Additionally, a corresponding control method and a building energy system are proposed.

Description

Control unit for a system and building energy system

Technical Field

The utility model relates to a control unit for a control system, in particular a building energy system, a corresponding control method and a building energy system. In particular, the utility model relates to improvements in energy management of such systems, and in particular of such building energy systems.

Background

Building energy systems with photovoltaic modules mounted on the roof of the respective building are known in the prior art. These photovoltaic modules generate electrical energy (or electrical power) in the form of electrical current, depending on the intensity of the solar radiation. The current thus generated can be used both for operating consumers inside the building (for example washing machines, kitchen appliances or coolers and air conditioners) and for being fed into an external power grid via the network connection points of the building. The additional electrical energy required for the operation of the consumers inside the building can be taken from the external electrical network via the network connection points.

Depending on the current weather conditions and the currently existing internal power demand inside the building, the network switched power may be positive (i.e., the power provided by the photovoltaic modules exceeds the power required inside the building) or negative (i.e., the power required inside the building exceeds the power provided by the photovoltaic modules). Therefore, in previously known building energy systems, the network exchange power is usually not predictable neither in sign nor in absolute value.

On the other hand, from the perspective of the network operator, a network exchange power with a predefined sign (i.e. positive or negative) may be desirable depending on the current state of the external grid. In particular, the network-switched power provided in a network-friendly manner may contribute to: the amplitude and/or frequency of the network voltage is stabilized within a predefined tolerance band. However, the provision of network-friendly network switching power is not practically achievable due to the unpredictable network switching power in previously known building energy systems.

Furthermore, in previously known building energy systems, the external grid is permanently loaded during the day, i.e. network exchange power different from zero must be constantly provided. Thus, from the perspective of network operators, the uncontrolled and unpredictable network exchange power that occurs in previously known building energy systems is an issue, for example, with respect to network stability. Furthermore, in economic terms, it is also desirable to minimize the network exchange power and, for example, to maximize the utilization of the own current within the building energy system. However, this self-demand optimization becomes significantly more difficult due to network exchange power that was unpredictable in previously known building energy systems. Finally, in previously known building energy systems, the following problems may arise: due to applicable regulations for feeding solar energy into an external power grid, undesirable regulation losses at the photovoltaic module (abregengungsverlust) must be accepted. EP2660954a1 shows a control unit for an energy system.

SUMMERY OF THE UTILITY MODEL

It is therefore the object of the present invention to provide a control device for a system, in particular a building energy system, a corresponding control method and a building energy system, which do not have the above-mentioned problems of the prior art. In particular, the object of the utility model is to provide a control device, a corresponding control method and a building energy system which reduce the load of the external power grid, enable a network-friendly provision of network-switched power and improve the internal energy management.

In order to solve this object, according to the utility model a control device, a control method and a building energy system are proposed having the features according to the utility model. The preferred embodiments of the present invention are preferred examples.

According to a first aspect of the utility model, a control unit for a system having an air conditioning device, a photovoltaic device as a generator unit (energy generator unit) for generating electrical energy and an energy storage for storing electrical energy is proposed, which system has a connection to a network connection point and is suitable for feeding electrical energy into an external electrical network (for example, a distribution network, an independent power supply network (Inselnetz) or a power transmission network) or for absorbing electrical energy from the external electrical network. The control unit may be configured to jointly (i.e. uniformly, comprehensively, superordinately) control the air conditioning unit, the generator unit and the energy store as a function of at least one condition of amperage and/or voltage relating to the fed-in or absorbed electrical energy (or electrical power). The common control of the air conditioning system, the photovoltaic system and the energy store comprises the control of the power absorbed by the air conditioning system, the power output by the photovoltaic system and the power absorbed or output by the energy store. The system may relate to a building energy system, for example to a building energy system having a power range (electrical power) of up to 10kW (e.g. for single family homes) or up to 100kW (e.g. for multi-family homes or commercial property). The air conditioning apparatus may relate to a heat pump unit or an air conditioning apparatus, and the air conditioning apparatus may include a power-controlled compressor.

The use of the proposed control unit makes it possible to coordinate the control of the air conditioning system, the generator unit and the energy store by means of a higher-level control or regulation of the components of the building energy system, and thus to optimize the control. This allows, in particular, the optimization of the power feed or power absorption at the network connection points in a type and manner that would not be possible if the components of the building energy system were controlled independently. Furthermore, a saving in hardware components can be achieved by a common control of the upper stages, for example by providing common electronic components such as inverters (english Inverter), capacitor banks (kondenserbank) and other power electronic components. The time constants of the remaining proprietary electronic components of the building energy system can be coordinated with one another, so that a faster control loop can be achieved. Finally, the common, superior control of the components of the building energy system enables a more intuitive handling of the building energy system and its components for the user.

Preferably, the at least one condition is at least one condition derived by the control unit from one or more measured quantities detected at the network connection point or at another point of the external electrical network. Additionally or alternatively, the control unit may be configured to be adapted to derive the at least one condition from a time of day (Tageszeit) and/or a predetermined schedule ("energy schedule") for feeding electrical energy into or drawing electrical energy (or electrical power) from the external electrical grid. The measured variable detected may relate to the feeding of energy into the external power grid or the absorption of energy from the external power grid.

By means of the at least one condition thus derived, the desired characteristic at the network connection point can be represented in a simple and transparent manner.

Preferably, the control unit is configured to be adapted to control a common buffer unit (e.g. a capacitor bank) for storing (e.g. intermediate storing) electrical energy for the air conditioning unit, the generator unit and the energy storage. Furthermore, the control unit may be configured to be adapted to control a common inverter for the air conditioning unit, the generator unit and the energy storage. Here, the control unit may comprise a common buffer unit and/or a common inverter. Further advantages result if the control unit is additionally configured to be suitable for controlling a common driver circuit for the semiconductor switches, a common sine filter or power factor correction filter (PFC), a common on-board network for the voltage supply and/or a common display for visualization, or comprises one or more of the mentioned elements.

Savings in material consumption and costs as well as in the module size of the individual components of the building energy system can be achieved by the above-described configuration of the control unit. The additional saving potential results from the mutually coordinated dimensioning of the electronic components of the building energy system. Due to the spatial proximity of the electronic components to each other, faster control or adjustment is also possible and the mounting and maintenance of the electronic components is simplified.

It is particularly advantageous if the control unit is configured and adapted to control the air conditioning system, the generator unit and the energy store in such a way that the current intensity and/or the voltage at the network connection point have predetermined characteristics.

In addition to the optimization of the demand itself, this configuration also makes it possible to provide services to an external power grid (for example a distribution network, a separate supply network or a transmission network). These services may include voltage maintenance, frequency maintenance, correction for reactive power, and reaction to demand side responses (e.g., in the form of energy lamps). Furthermore, it is possible to react to price signals and to establish and comply with a time schedule for current feed ("timetable").

In an embodiment of the utility model, the control unit may be configured and adapted to control the air conditioning unit, the generator unit and the energy storage such that the energy fed into the external power grid is reduced to zero.

Accordingly, the self-consumption of the building energy system can be optimized (i.e., increased). This self-demand optimization is suitable in order to avoid feeding current into the external power grid under economically unfavorable conditions or in order to reduce the load of the external power grid.

In an embodiment, the control unit may further be configured to be adapted to increase or maximize the current feed under economically advantageous conditions by suitable control of the air conditioning device, the generator unit and the energy storage.

In one embodiment of the utility model, the measured variable detected relates to the network voltage. The control unit is then preferably configured as a controller adapted to control the inverters for the common inverter to provide a reactive power dependent on the detected measurement quantity in dependence on the detected measurement quantity.

By this configuration, reactive power can be provided as a service to the external Grid within the framework of the Smart Grid (Smart Grid), and thus reactive power in the external Grid (e.g. distribution network) can be corrected.

In one embodiment of the utility model, the detected measurement variable relates to (for example) the frequency of the network voltage. The control unit is then preferably configured to control the active power of the air conditioning system and/or the energy store (i.e. the energy/power output to the external power grid or the energy/power absorption from the external power grid) as a function of the detected measured variable with respect to frequency and thereby influence the frequency of the network voltage (possibly together with other energy systems configured in a network-friendly manner). The control unit can be configured to control the air conditioning system, the generator unit and the energy store in such a way that positive control power is supplied to the external power grid in the case of a real value of the frequency of the network voltage below a target value for the frequency of the network voltage, and negative control power is supplied to the external power grid in the case of a real value of the frequency of the network voltage above a target value for the frequency of the network voltage.

By this configuration, regulated power can be provided as a service to the external grid within the framework of the smart grid, and thus the frequency in the external grid (e.g. independent power supply network or distribution network) can be stabilized.

In an embodiment of the utility model, the system may additionally comprise a heat generator. The heat generator may for example be configured to generate heat by burning a fuel, e.g. a fossil fuel such as oil or natural gas, or e.g. wood chips. Then, the control unit may be configured to be adapted to additionally control or regulate the heat (heating power) generated by the heat generator. A particular advantage results when the control unit is configured and adapted to control the heat generated by the heat generator in dependence on the actual value and the nominal value of the energy absorption of the air conditioning apparatus. In this case, the setpoint value for the energy absorption of the air conditioning system is derived from the joint control of the air conditioning system, the photovoltaic system and the energy store. Furthermore, the control unit can control the energy absorption of the air conditioning system in such a way that it corresponds to a target value. For example, if the air conditioning system relates to a heat pump in heating operation, the heat generated by the heat generator can be increased in order to simultaneously reduce the energy absorption (and thus the heating power) of the heat pump. Conversely, the heat generated by the heat generator can be reduced in order to simultaneously increase the energy absorption (and thus the heating power) of the heat pump. Alternatively, the heat pump may be used for cooling operation.

In other words, by the above-described common control, the current demand (power demand) and the heat demand can be coordinated with each other. Thus, the desired feed characteristics can be achieved at the network connection point without comfort loss.

In an embodiment of the utility model, the air conditioning apparatus comprises an inverter, and the control unit is configured to be adapted to control the inverter of the air conditioning apparatus. Additionally or alternatively, the generator unit may comprise a photovoltaic module having an inverter, and the control unit may be configured to be adapted to control the inverter of the generator unit. Additionally or alternatively, the energy storage may comprise a battery (e.g. a lithium ion battery) with a charge regulator, and the control unit may be configured to be adapted to control the charge regulator.

According to a further aspect of the utility model, a building energy system is proposed, which can be connected to a network connection point and is suitable for feeding electric energy into an external power grid or for absorbing electric energy from an external power grid, and which comprises an air conditioning unit, a generator unit for generating electric energy, an energy store for storing electric energy, and a control unit according to the above aspect of the utility model or its configuration.

The building energy system may additionally include a heat generator. The heat generator may for example be configured to generate heat by burning a fuel, e.g. a fossil fuel such as oil or natural gas, or e.g. wood chips. Then, the control unit may be configured to be adapted to control the heat generated by the heat generator.

According to a further aspect of the utility model, a method is proposed for controlling a system having an air conditioning system, a photovoltaic system as a generator unit for generating electrical energy and an energy store for storing electrical energy, the system being connected to a network connection point and being suitable for feeding electrical energy into an external electrical network or for absorbing electrical energy from the external electrical network. The method may comprise controlling the air conditioning system, the generator unit and the energy store jointly as a function of at least one condition for the current intensity and/or the voltage associated with the fed or absorbed electrical energy. The common control of the air conditioning system, the photovoltaic system and the energy store comprises the control of the power absorbed by the air conditioning system, the power output by the photovoltaic system and the power absorbed or output by the energy store.

Preferably, the method comprises the further steps of: one or more measured variables detected at the network connection point or at another point of the external power network are received, and at least one condition is derived from the received measured variables. Additionally or alternatively, the method may comprise deriving the at least one condition from a time of day and/or a predetermined schedule for feeding or absorbing electrical energy into or from an external electrical grid.

In a preferred embodiment, the control of the air conditioning system, the generator unit and the energy store can be carried out in such a way that the current intensity and/or the network voltage at the network connection point have predetermined characteristics. A particular advantage results if the control is carried out in such a way that the energy fed into the external power grid is reduced to zero.

In one embodiment of the utility model, the received measured variable relates to (for example) the frequency of the network voltage. In this case, the method preferably has the following further steps: the active power of the air conditioning system and/or of the energy store (i.e. the energy/power output to or absorption from the external power grid) is controlled as a function of the received measured variable relating to the frequency.

In one embodiment of the utility model, the received measured variable relates to (for example) the frequency of the network voltage. In this case, the control of the air conditioning system, the generator unit and the energy store is preferably carried out in such a way that positive control power is supplied to the external power supply system in the case of a situation in which the actual value of the frequency of the network voltage is below the target value of the frequency of the network voltage and negative control power is supplied to the external power supply system in the case of a situation in which the actual value of the frequency of the network voltage is above the target value of the frequency for the network voltage.

In an embodiment of the present invention, the system may additionally include a heat generator. In this case, the method advantageously has the following further steps: controlling the heat generated by the heater. In particular, the heat generated by the heat generator may be controlled in dependence on the actual value and the nominal value of the energy absorption of the air conditioning plant. The setpoint value for the energy absorption of the air conditioning system is derived from the joint control of the air conditioning system, the photovoltaic system and the energy store.

Drawings

Other advantageous configurations (to which the utility model is not limited in its scope, however) emerge from the following description on the basis of the attached drawings. Here, in the drawings, the same elements are provided with the same reference numerals, and the description of the elements already described is not repeated. In particular, the figures show:

FIG. 1 shows an exemplary schematic diagram of a building energy system having an energy generator unit;

FIG. 2 shows an exemplary schematic diagram of a building energy system with an energy generator unit and an energy storage;

FIG. 3 shows an exemplary schematic diagram of a building energy system with an energy generator unit, an energy storage and an air conditioning device;

FIG. 4 shows an exemplary schematic diagram of a building energy system according to an embodiment of the utility model;

FIG. 5 illustrates another exemplary schematic diagram of the building energy system of FIG. 4;

FIG. 6 shows an exemplary schematic diagram of a building energy system according to other embodiments of the utility model;

fig. 7 illustrates another exemplary schematic of the building energy system of fig. 6.

Detailed Description

Fig. 1 shows a building energy system (generally: system) with an energy generator unit 20 for generating electrical energy. The energy generator unit 20 can relate to a photovoltaic system with a photovoltaic module 21 and an inverter 22 and, if necessary, further power electronics. The energy generator unit 20 is connected (possibly via an electricity meter 75, for example a solar energy meter, and possibly via a feed and reference meter 70) to a network connection point (network transmission point) 90, which in turn is connected to an external electrical network 60. Additionally, the energy generator unit 20 and the network connection point 90 are connected to one or more consumers 80 via an internal power grid. The possible directions of the current flow (i.e. the direction of energy transmission) are shown here by small arrows at the respective connecting lines between the mentioned components of the building energy system.

In the building energy system shown in fig. 1, the problems mentioned at the outset with regard to the loading of the external power grid 60 and the regulating losses at the energy generator unit 20 may occur.

A first improvement can be achieved by the building energy system shown in fig. 2. In addition to the above-mentioned components, the building energy system also comprises an energy store 30 for storing electrical energy, which may contain an inverter 32, a charging regulator and a battery (battery) 31 and, if necessary, further power electronics. In the event of an excess or deficiency of the electrical power provided by the energy generator unit 20, the network exchange power can be reduced by appropriate energy absorption (power absorption) or energy output (power output) by the energy store 30. Here, however, the extent of the possible reduction of the network switching power is closely related to the (limited) capacity of the energy store (i.e. the battery 31), so that the advantages of improving the reduction of the network switching power and the disadvantages of a higher acquisition cost for the energy store have to be weighed against.

Fig. 3 schematically illustrates another example of a building energy system. In addition to the energy generator unit 20 and the energy store 30, the building energy system also comprises an air conditioning system 10. In addition to the components mentioned above, the energy generator unit 20 can also comprise an energy intermediate store (buffer unit) 23, which can be, for example, a capacitor bank. The energy store 30 may likewise comprise an energy intermediate store 33. The air conditioning system 10 may comprise a (power-controlled, i.e. speed-controlled) compressor 11 as well as an inverter 12 and an energy intermediate storage 13. The air conditioning apparatus 10 may relate to, for example, a heat pump unit or an air conditioning apparatus.

The energy generator unit 20, the energy store 30 and the air conditioning system 10 are each connected to a network connection point 90, and energy (power) can be output to this network connection point (energy generator unit 20 and energy store 30) or energy (power) can be absorbed from this network connection point (air conditioning system 10 and energy store 30). However, the above-mentioned problems may also occur in such building energy systems.

Fig. 4 illustrates a building energy system according to an embodiment of the present invention. The building energy system comprises an energy generator unit 20, an energy storage 30 and an air conditioning device 10. Unless otherwise stated, the energy generator unit 20, the energy store 30 and the air conditioning system 10 can each have the electronic components mentioned above in connection with fig. 1 to 3. The building energy system is connected to the network connection point 90 and via the network connection point to the external electrical grid 60 and can absorb electrical energy (or power) from the external electrical grid 60 or output electrical energy to the external electrical grid. The building energy system also comprises a control unit 100 for the building energy system, which control unit can be constructed as part of the air conditioning system 10, but can also be constructed separately from the latter. The control unit 100 is connected to the air conditioning system 10, the energy generator unit 20 and the energy store 30, for example, via a data bus 105 (see fig. 6), in such a way that the control unit 100 can control or control the air conditioning system 10, the energy generator unit 20 and the energy store 30 (i.e., the operation thereof). As shown in fig. 4, the energy generator unit 20 and the energy store 30 can be connected to the network connection point 90 via the air conditioning system 10, i.e. the air conditioning system 10 can be designed as a central element (central smart grid element) of the building energy system.

As described above, the energy generator unit 20, the energy store 30 and the air conditioning system 10 may each comprise an energy intermediate store and/or an inverter. However, according to the utility model, the control unit 100 can comprise or at least be connected separately to a common energy intermediate store (buffer unit) 103, such as a capacitor bank, and/or a common inverter 102 for the energy generator unit 20, the energy store 30 and the air conditioning device 10 and be configured for the control thereof. The former case is shown in fig. 5. Furthermore, the control unit 100 may comprise or at least be connected to further common power electronics for the energy generator unit 20, the energy store 30 and the air conditioning system 10 and be designed for the control thereof.

The building energy system in the embodiment of the present invention may further include a heat generator (e.g., a burner or a heat pump) 15 in addition to the air conditioner 10, the energy generator unit 20, and the energy storage 30. For example, the heat generator may be configured and adapted to generate heat by burning fuel. The fuel may relate to fossil fuel such as oil or natural gas or wood chips. The heat generator 15 may be connected to the air conditioner 10. The control unit 100 is connected to the heat generator 15, for example, via an internal data bus 105 (see fig. 6), in such a way that the control unit 100 can control or control the heat generator 15 (i.e. its operation, in particular the heat generated or the heating power). A building energy system with an air conditioning device 10, a heat generator 15, an energy generator unit 20 and an energy storage 30 is shown in fig. 6.

The control unit 100 is configured and adapted to jointly (i.e. uniformly or in coordination with each other) control or operate or regulate the air conditioning device 10, the energy generator unit 20, the energy storage 30 and, if necessary, the heat generator 15 as a function of at least one condition for the current strength and/or the voltage (in the form of a current) in relation to the electrical energy fed in or absorbed by the network connection point 90. In other words, the control unit 100 controls the air conditioning system 10, the energy generator unit 20, the energy store 30 and, if necessary, the heat generator 15 in such a way that the current intensity and/or the voltage at the network connection point 90 satisfies at least one condition, i.e. has the desired (predetermined) characteristics. Here, the control unit 100 controls, for example, the power absorbed by the air conditioning system 10, the power output by the energy generator unit 20 and/or the power absorbed or output by the energy store 30 and/or the heat (heating power) generated by the heat generator 15 if necessary.

The heat (heating power) generated by the heat generator 15 can be controlled according to the actual value and the rated value of the power absorption of the air-conditioning apparatus 10 according to the above-described common control. For example, if the actual power consumption of the air-conditioning apparatus 10 is higher than the rated power consumption, the heating power of the heat generator 15 may be increased so as to compensate for the decrease in the heating power of the air-conditioning apparatus 10 that occurs when the power absorption of the air-conditioning apparatus 10 decreases. Conversely, if the actual power absorption of the air conditioning system 10 is lower than the setpoint power absorption, the heating power of the heat generator 15 can be reduced in order to compensate for the increase in heating power of the air conditioning system 10 which occurs when the power absorption of the air conditioning system 10 increases. Accordingly, the air conditioning apparatus 10 can be controlled such that its actual power consumption corresponds to the rated power consumption. In other words, by the above-described common control, the current demand (power demand) and the heat demand can be coordinated with each other, and thus a loss of comfort is avoided.

As described above, the air conditioning apparatus 10 may include the power-conditioned compressor 11 and the inverter 12 and other power electronic components if necessary. Then, controlling the air conditioning device 10 by the control unit 100 may be performed by controlling the compressor 11 (or by its rotational speed) and/or the inverter 12. The energy generator unit 20 may comprise a photovoltaic module 21 and an inverter 22 and, if necessary, further power electronics. The control of the energy generator unit 20 can be effected by the control of the inverter 22 and/or the power electronics. For example, the submodules of the photovoltaic module 21 may be temporarily separated from the circuit of the energy generator unit 20 in order to temporarily reduce the power output by the energy generator unit 20. The energy storage 30 may include an inverter 32, a charging regulator and a battery 31 and other power electronics if necessary. The energy store 30 can be controlled by a charging regulator and/or by an inverter 32.

As described above, the control unit 100 is configured and adapted to collectively control the air conditioning device 10, the energy generator unit 20, the energy storage 30 and, if necessary, the heat generator 15 in dependence of at least one condition of the current intensity and/or the voltage at the network connection point 90. According to a possible first condition, the energy output (power output) to the external power grid 60 is reduced to as great an extent as possible, ideally to zero, i.e. the network switching power is regulated to zero or negative values (power absorption from the external power grid 60). Satisfying this first condition results in increasing or maximizing self-utilization (self-consumption). Such a control by the control unit 100 may be advantageous especially around noon hours, since there is usually a maximum solar power supply at noon hours.

In order to satisfy the first condition, the energy store 30 can be controlled in such a way that power is absorbed, i.e. the energy store 30 or the battery 31 is charged. The air conditioning system 10 can be controlled in such a way that its power absorption is increased. When the air conditioning system 10 is operated as a heater, the heating power which is additionally accumulated due to the increase in the power consumption of the air conditioning system 10 can be compensated by reducing the heating power of the heat generator 15. By the above-described common control of the air conditioning system 10, the energy store 30 and, if necessary, the heat generator 15, the first condition can be observed and, in some cases, the regulation of the energy generator unit 20 can be avoided at the same time, i.e. the energy generator unit 20 can be controlled at the same time in such a way that the power output of the energy generator unit 20 is maximized. The adjustment of the power output of the energy generator unit 20 must be performed only when the first condition cannot be observed despite the above-described common control.

The control unit 100 may be configured and adapted to determine at least one condition for the amperage and/or the voltage in response to a signal from a network operator of the external electrical grid 60. This signal may for example be made via a data connection (external data bus) 65 provided by the network operator. One possible second condition determined in response to a signal from the network operator typically involves power feeding or power sinking at the network connection point 90. An example for the second condition is described below.

For example, the second condition may be determined or derived corresponding to load control (demand side response) by the network operator. The load control may include the delivery of "traffic light signals" related to the feed into the external electrical grid 60 desired by the network operator. The control unit 100 may be configured to be suitable for jointly controlling the air conditioning device 10, the energy generator unit 20 and the energy storage 30 in such a way that a feed desired by the network operator is achieved, i.e. the second condition relates to a desired power feed at the network connection point 90. Preferably, the common control is carried out in such a way that control losses of the energy generator unit 20 are avoided. As described above, a variation in the heating power of the air-conditioning apparatus 10 due to a change in the power absorption of the air-conditioning apparatus 10 by the common control can be compensated for by the corresponding control of the heating power of the heat generator 15.

Alternatively or additionally, the second condition may be determined or derived from the price signal. The control unit 100 can be configured, for example, to jointly control the air conditioning system 10, the energy generator unit 20 and the energy store 30 in such a way that the feed into the external power grid 60 is reduced to the greatest possible extent if the price signal indicates that the electricity prices are low, and conversely, if the price signal indicates that the electricity prices are high, it is increased as much as possible. Also in this case, the second condition relates to a desired power feed or power absorption at the network connection point 90.

In this case, the reduction in the feed-in can be achieved by increasing the power absorption of the energy store 30 and the air conditioning system. Increasing the feed-in can be achieved by reducing the power absorption of the energy store 30 and the air conditioning system or by increasing the power output of the energy store 30 and, if necessary, of the energy generator unit 20. The common control is preferably also carried out in such a way that control losses of the energy generator unit 20 are avoided. As described above, a variation in the heating power of the air-conditioning apparatus 10 due to a change in the power absorption of the air-conditioning apparatus 10 by the common control can be compensated for by the corresponding control of the heating power of the heat generator 15.

The above measures represent the service of the power transmission network (as an example of the external grid 60) within the framework of a smart grid (smart grid).

Fig. 7 schematically shows the building energy system from fig. 6, in which the control unit 100 can receive data from the network operator 61 via the external data bus 65. Furthermore, an internal data bus 105 is shown, which connects the control unit 100 to the air conditioning system 10, the heat generator 15, the energy generator unit 20, the energy store 30 and, if necessary, the heat generator 15 (not shown here).

At least one condition for the current intensity and/or voltage can be derived from one or more measured variables. These measured variables can be detected at the network connection point 90 or also at another point of the external power network 60. In the latter case, the data of the measured variables need to be transmitted to the building energy system, for example via a data connection (external data) 65 provided by the network operator. Accordingly, the control unit 100 may be configured to be adapted to receive and process the detected measurement quantity.

In an embodiment of the utility model, the detected one or more measured variables relate to the energy feed into the external electrical network 60 or the energy absorption from the external electrical network 60.

For example, the measured variable may relate to a network voltage of the external power network 60 (e.g., a power distribution network). In this case, one possible third condition for the amperage and/or voltage at the network connection point 90 may relate to a desired phase relationship between the voltage and the amperage (or between the complex voltage vector and the complex amperage vector). In this case, the desired phase relationship can be derived from the network voltage. Reactive power (positive or negative) is supplied to the external grid 60 according to the phase relation established at the network connection point 90. The control unit 100 may thus be configured to be suitable for controlling the air conditioning system 10, the energy generator unit 20 and the energy store 30 in such a way that a desired phase relationship exists between the voltage and the current strength at the network connection point 90, that is to say that reactive power is supplied to the external power grid 60. In particular, the control unit 100 may be configured and adapted to control the common inverter 102 such that a desired phase relationship exists between the voltage and the amperage at the network connection point 90, i.e. the third condition is fulfilled.

The phase relationship or the reactive power supplied is preferably dependent on the detected measured variable (network voltage). That is, if the detected network voltage exceeds its rated value, then (positive) reactive power must be supplied to the external grid 60 for voltage maintenance. The desired phase angle between the voltage and the current strength at the network connection point 90 may thus depend on the detected network voltage, more precisely on the difference between the detected network voltage and its nominal value.

The above measures serve to keep the voltage at the network connection point 90 within a tolerance band, thus representing a service to the distribution network (as an example of the external grid 60) within the framework of the smart grid. As a further service to the electricity distribution network, the reactive power in the electricity distribution network can be corrected by a suitable selection of the desired phase relationship.

Furthermore, the measured variable detected may relate to the frequency of the network voltage in the external power network 60 (e.g. a separate power supply network or a power distribution network). In this case, a possible fourth condition for the amperage and/or voltage at the network connection point 90 may relate to a desired power (active power) fed into the external electrical network 60 at the network connection point 90. The desired power (active power) can be derived from the frequency of the network voltage. Thus, the control unit 100 may be configured to be adapted to control the air conditioning device 10, the energy generator unit 20 and the energy storage 30 such that the desired active power is present at the network connection point 90. The active power is preferably dependent on the detected measurement variable (frequency of the network voltage). In particular, the control unit 100 may be configured and adapted to control the energy output (or energy absorption, in general energy balance or power balance) of the energy generator unit 20, the air conditioning system 10 and the energy store 30 as a function of the detected measured variables, to be precise in such a way that the fourth condition is fulfilled. In order to avoid control losses of the energy generator unit 20, the control unit 100 is preferably configured to control the energy absorption of the air conditioning system 10 and/or of the energy store 30 or the energy output of the energy store 30 as a function of the detected measured variable. As described above, it is possible to compensate for a change in the power balance of the air-conditioning apparatus 10 by controlling the heating power of the heat generator 15 accordingly.

If the detected frequency of the network voltage exceeds its nominal value (e.g., about 50.2Hz), the output power (real power) of the building energy system (or the real power of its components) may be reduced to contribute to frequency stabilization. The desired active power depends on the detected frequency of the network voltage, more precisely on the difference between the detected frequency of the network voltage and its nominal value.

The above measures are used for frequency maintenance of the external power grid 60 and thus represent a service to a distribution network or a separate supply network (as an example of the external power grid 60) within the framework of a smart grid.

Alternatively or additionally, for the case of a frequency of the network voltage as the detected measurement variable, the control unit 100 may be configured to be adapted to supply the regulated power (positive or negative) in a desired range to the external electrical network 60 (e.g. a distribution network or a separate supply network). This can be achieved by appropriate joint control of the air conditioning device 10, the energy generator unit 20 and the energy storage 30. Thus, one possible fifth condition may relate to a quantity (e.g., sign and absolute value) of regulated power provided to the external power grid 60. In the case of a frequency of the network voltage whose actual value is lower than the nominal value of the frequency of the network voltage, a positive regulating power should be provided, i.e. the power is delivered to the external power grid 60. In the case of the actual value of the frequency of the network voltage exceeding the nominal value of the frequency of the network voltage, a negative regulating power should be provided, i.e. power is absorbed by the building energy system. Preferably, the above-described common control is performed such that a regulation loss of the energy generator unit 20 is avoided. To provide positive regulated power, the power absorption of the energy storage 30 may be reduced or its power output increased. At the same time, the power consumption of the air conditioner 10 can be reduced. The heating power of the heat generator 15 may be increased accordingly so as to keep the total heating power (of the air conditioner 10 and the heat generator 15) constant. In order to provide negative control power, the power absorption of the energy store 30 and/or of the air conditioning system 10 can be increased. The heating power of the heat generator 15 can be reduced accordingly in order to keep the total heating power constant.

Additionally or alternatively, the at least one condition may be derived from a time of day. A possible sixth condition derived from time of day generally relates to power feed or power consumption at the network connection point 90.

For example, the feed into the external grid may be reduced as much as possible during certain daytime hours (e.g., around noon hours). Suitable measures for reducing the power feed are described above.

Furthermore, the sixth condition may be derived from a predetermined schedule for feeding electrical energy (electric power) into the external electrical network 60 or for absorbing electrical energy (electric power) from the external electrical network 60. The schedule may be adapted by the control unit 100 according to requirements of the external power grid 60 (or network operator) received via the external data bus 65.

The above measures represent the service of the power transmission network (as an example of the external grid 60) within the framework of the smart grid.

It is to be understood that for the described building energy system or the described control unit 100, switching can be made between different detected measured variables to be taken into account and between different conditions to be met. The switching can take place automatically or by user input and, if necessary, in accordance with the requirements of the network operator.

The building energy system according to the present invention is described above based on a specific configuration. Unless otherwise stated, the disclosure shall extend in the same way to a respective control unit for a building energy system and to a respective control method for a building energy system having respective method steps.

Without being limited to a particular embodiment, the present invention has been further illustrated based on a particular configuration. In particular, features of different embodiments may be combined and may also be used in other embodiments.

Claims (11)

1. A control unit (100) for a system,

the system comprises an air conditioning system (10), a photovoltaic system (20) for generating electrical energy and an energy store (30) for storing the electrical energy,

wherein the system is connected to a network connection point and is adapted to feed electric energy into an external power grid (60) or to absorb electric energy from the external power grid (60),

wherein the control unit (100) is a controller which is configured to jointly control the air conditioning device (10), the photovoltaic device (20) and the energy store (30) as a function of at least one condition of current intensity and/or voltage relating to the electrical energy fed into or absorbed from the external electrical grid (60) and to provide reactive power depending on the detected measurement variable by controlling a common inverter for the air conditioning device (10), the photovoltaic device (20) and the energy store (30) as a function of the detected measurement variable, wherein the joint control of the air conditioning device (10), the photovoltaic device (20) and the energy store (30) comprises a control of the power absorbed by the air conditioning device (10), the power output by the photovoltaic device (20) and the power absorbed or output by the energy store (30) Control of the power of;

wherein the at least one condition is at least one condition derived by the control unit (100) from one or more measured quantities detected at the network connection point or at another point of the external electrical network (60);

the measured variable is a network voltage.

2. The control unit (100) of claim 1,

the control unit is configured to derive the at least one condition as a function of time of day and/or as a function of a predetermined schedule for feeding electrical energy into the external electrical grid (60) or for absorbing electrical energy from the external electrical grid (60).

3. The control unit (100) according to claim 1 or 2,

the control unit is further configured and adapted to control a common buffer unit for storing: the electrical energy is used for the air conditioning system (10), the photovoltaic system (20) and the energy store (30).

4. The control unit (100) according to claim 1 or 2,

the detected measured variable relates to the frequency of the network voltage, and the control unit (100) is configured to control the active power of the air conditioning system (10) and/or the active power of the energy store (30) as a function of the detected measured variable relating to the frequency;

and/or the presence of a gas in the gas,

the detected measurement variable relates to the frequency of the network voltage, and the control unit (100) is configured to control the air conditioning device (10), the photovoltaic device (20) and the energy store (30) such that a positive regulating power is supplied to the external power grid (60) in a state in which the actual value of the frequency of the network voltage is lower than the nominal value of the frequency of the network voltage, and a negative regulating power is supplied to the external power grid (60) in a state in which the actual value of the frequency of the network voltage is higher than the nominal value of the frequency of the network voltage.

5. The control unit (100) according to claim 1 or 2,

the system additionally comprises a heat generator (15),

and the control unit (100) is configured and adapted to control the heat generated by the heat generator (15).

6. The control unit (100) according to claim 5, wherein the heat generator (15) is adapted to generate heat by burning fuel.

7. The control unit (100) according to claim 2, characterized in that the control unit (100) is further configured and adapted to control the air conditioning device (10), the photovoltaic device (20) and the energy storage (30) such that the energy feed into the external electrical grid (60) is reduced to zero.

8. The control unit (100) according to claim 5, characterized in that the control unit (100) is configured and adapted to control the heat generated by the heat generator (15) in dependence of an actual value and a nominal value of the energy absorption of the air conditioning apparatus (10).

9. A building energy system, characterized in that,

the building energy system is adapted to be connected to a network connection point for feeding electrical energy into an external electrical grid (60) or for absorbing electrical energy from the external electrical grid (60),

wherein the building energy system comprises an air conditioning device (10), a photovoltaic device (20) for generating electrical energy, an energy storage (30) for storing electrical energy and a control unit (100) according to any one of claims 1 to 8.

10. The building energy system according to claim 9, characterized in that the building energy system additionally comprises a heat generator (15).

11. The building energy system according to claim 10, characterized in that the control unit (100) is configured and adapted to control the heat generated by the heat generator (15).

Images