ENERGY MANAGEMENT SYSTEM FOR CONTROLLING DOMESTIC ENERGY CONSUMPTION

Description

[0001] The invention relates to an energy management system according to the preamble of claim 1 and a method according to claim 4 for controlling the energy consumption of an electrical device of an energy consumer in an energy management system.

[0002] Energy management systems with a data network and at least one energy consumer connected to an energy generator in a building's power grid are known on the market. The building's power grid is connected to the power grid via an electricity meter connected to a connecting line. The energy generator is electrically integrated into the building's power grid via an inverter and a generator line. The energy consumer is connected to the building's power grid via an electrical consumer connection located between the inverter and an electricity meter, and a controller for the energy consumer is connected to the data network. DE 10 2010 017264 A apparently describes an energy management system for a house.

[0003] The object of the invention is to provide a cost-effective device with which electricity generated by an energy generator is at least partially used by an energy consumer.

[0004] The object is achieved by an energy management system according to the features of claim 1 and a method according to the features of claim 4.

[0005] An energy meter is integrated into the connection line with a power measuring unit and the energy meter is connected to the data network with a first data connection.

[0006] It is advantageous if the energy meter is connected to an internet coupler, the router or the controller via the first data connection.

[0007] In another advantageous embodiment, the controller is connected to the internet coupler, the internet coupler is connected to the router and the energy meter is connected to the router.

[0008] According to the inventive method for controlling the energy consumption of an electrical device of an energy consumer with an energy management system, the electrical power is determined in the energy meter based on the current flowing through the connecting cable. The energy meter determines the energy generated by the energy generator in the building's power grid less the energy consumed in the building's power grid. It is determined whether there is a surplus of power fed into the building's power grid by the energy generator. Depending on the value of the surplus power, the electrical device is controlled by the energy consumer's controller.

[0009] According to a further advantageous idea, depending on the value of the surplus electrical power, the electrical device is controlled by the controller in such a way that at least a portion of the surplus electrical power of the building's power grid is consumed by the electrical device of the energy consumer.

[0010] Alternatively, the electrical consumer is operated if electricity were supplied from the building's power grid to the power grid, thus at least largely reducing or avoiding feed-in to the power grid.

[0011] In an advantageous method step, the energy management system regulates the power consumption from the power grid or the power supply to the power grid to zero, with the available power range of the electrical device. Any surplus electrical power from the building's power grid is supplied to the electrical device. The energy consumer is, in particular, a heat pump or an electric heating device. The power of the energy consumer is selected such that the power supply to the power grid is regulated to zero, thus optimizing the feed-in, in particular minimizing the feed-in to the power grid.

[0012] With a favorable availability forecast of excess electrical power in the energy management system, a stability value for the energy generator's future yield is determined. The availability forecast is based primarily on historical energy values ​​determined by the energy meter and / or weather data. Based on a comparison of the stability value ST with a target stability value, the output of the electrical device is specified, ensuring trouble-free operation of the energy consumer over a certain time interval.

[0013] The electrical device generates thermal energy depending on the excess electrical power. In particular, with reverse control, which aims to achieve a setpoint of thermal energy or a setpoint temperature of a heating system at the end of a heating interval, the electrical device is switched on when a point in time is reached at which the expected excess electrical power is sufficient to achieve the amount of thermal energy or the setpoint temperature at the end of the heating interval.

[0014] It is advantageous if there are other electrical consumers in the building's power grid whose power consumption is taken into account in the energy meter.

[0015] The energy meter advantageously performs a power measurement based on voltage and current. The power measurement values ​​are stored in the energy management system or made available to it. The power measurement values ​​are advantageously stored in a data storage device of the energy meter, the router, the internet coupler, or the controller. Alternatively, it is also advantageous to store the power measurement values ​​on a server connected to the energy management system or the data network via the router. For this purpose, the router is advantageously connected to the server via the internet.

[0016] The energy management system is advantageously operated without an internet connection. In particular, the power is measured in the energy meter. In the energy management system, advantageously in the energy meter, the internet coupler, or even the controller, the measured power is compared with a target value, whereby the difference between the target value and the measured power should ideally be equal to or close to zero. If positive power values ​​are available, it can be assumed that power is being supplied from the building's power grid to the power grid. It is advantageous for the user to use the power generated by the energy generator itself in the building's power grid. As soon as positive power values ​​are available, a determination is made as to whether these positive power values ​​are sufficient to operate the energy consumer or the energy consumer's electrical device.

[0017] If sufficient positive power values ​​are present over a given period of time, a forecast can be made regarding the expected yield for a future period. As soon as a given positive power value, especially positive power values, are present over a given period of time, the electrical device is switched on.

[0018] The electrical device is controlled in such a way that, as far as possible, no power is supplied from the building's electrical network to the power grid. Once the electrical device is in operation, its consumption is regulated so that the energy meter detects a power flow of as little as possible.

[0019] This control is advantageously implemented in such a way that a certain percentage of power is always delivered to the power grid. This percentage can also be a fixed, small power value, for example, 10 W. It is advantageous for the small power value to be as small as possible, and less than 10 W, for example, even one watt. For example, if the energy consumer has a power range of 500 W to 5 kW, the power consumption of the electrical device can be varied between 500 W and 5 kW.

[0020] Since, on the one hand, the production by the energy generator can fluctuate, for example by a photovoltaic system or a wind turbine integrated into the power grid, a fluctuation in the energy generator can be compensated for by an advantageous variation in the power spectrum between, for example, 500 W and 5 KW. As soon as the energy meter determines a power or current that deviates from a target value of the power flow through the energy meter, the power of the energy consumer is adjusted so that only exactly as much power is delivered to the energy consumer as the excess of the building's power grid has available. As described above, this is advantageously achieved by selecting the power of the energy consumer, in particular of the electrical device of the energy consumer, in such a way that a target value is reached in the energy meter.This target value is preferably 0.1 percent of the power output of the energy producer or consumer, or a fixed power value as close to zero as possible, such as a value between -50 and +50 W. Ideally, a value just above zero is chosen. This avoids the relatively expensive consumption of electricity. Furthermore, it prevents excessive self-generated energy from being fed into the power grid.

[0021] Accordingly, the power of the electrical device is advantageously increased when the power measured by the energy meter is above the target value or continues to rise above the target value. The power of the electrical device is advantageously reduced as soon as the target value is undershot or continues to fall.

[0022] The energy consumer is advantageously a heat pump, particularly electric heat pumps and other heat pump units. An electric compressor has a significant influence on power consumption. This is advantageously a variable-speed compressor controlled by an inverter. As soon as the setpoint is exceeded, the compressor speed is increased; as soon as the setpoint is undershot, the speed is advantageously reduced. If the compressor's lowest operating limit is reached, the system must be switched off completely or, alternatively, power must be drawn from the grid. If power is drawn from the grid, in order to keep the heat pump running, it is advantageous to set it to a low speed, particularly a minimum speed.

[0023] It is advantageous to keep a history of the measured power data in the energy management system, and particularly in the energy meter itself. Based on this, a stability factor is calculated based on historical data, at least over a certain time interval. For example, the amount of surplus power generated over the last hour is determined. If a minimum value is reached, it can be assumed that electricity can be supplied to the electrical device from the power grid relatively reliably for the foreseeable future. The system does not require an internet connection for this purpose. It is advantageous to operate autonomously and does not require any data from the inverter or the energy generator. It is advantageous to monitor in the energy meter whether power is being supplied to the grid or drawn.

[0024] In a further advantageous embodiment of the invention, a weather forecast is included in the calculation of the stability factor in addition to, or instead of, the history. As long as solid and stable weather data is available, in particular sunshine for a photovoltaic system or a stable profit forecast for a wind turbine, the energy consumer can be switched on. It is also advantageous not to switch on the energy consumer immediately, but only when the electrical device is switched on and thus thermal energy is generated at a predicted end time. In a "last order" manner, the electrical device is switched on only at a late or latest possible time in order to have provided the required amount of thermal energy by a specified time or to have reached a target temperature of a heating system.The heating system can be a water-based heating system, an air-based heating system, a hot water tank or even a drinking water tank.

[0025] According to a further advantageous embodiment, the energy consumer is an electric radiator. This can be an electric radiator of a hot water tank or of an underfloor or wall heating system. An electric storage heater is also encompassed by the invention, but in particular of the type in which the output of the electric radiator is variable. The energy consumer is advantageously controlled by an inverter, so that the output of the electric radiator, the hot water tank, an underfloor or wall heating system is variable, specifically in such a way that the output of the electric radiator is adjusted depending on the excess output of the building's power grid. This occurs in a similar way to a heat pump, except that in this case, no additional thermal environmental energy is absorbed by the heating system itself.

[0026] In addition to historical data, performance data, and the weather forecast, a forecast can advantageously incorporate other building data, such as usage data. This allows additional usage data to be entered into the energy management system, such as weekly schedules, vacation or peak times, as well as specific comfort programs for a building. All of this has a particular impact on so-called reverse control, i.e., late activation according to the "last order" principle described above.

[0027] There is no connection between the power generator's inverter or the power generator itself and the data network. It is preferable to have a data connection between the inverter and the router or, outside the data network, to the internet. In particular, there is no data connection to the energy meter, the controller, or the internet coupler, and no data from the power generator's inverter or the power generator is exchanged with the data network.

[0028] The figure shows an energy management system.

[0029] The energy management system 100 essentially consists of a building power grid 400 and a data network 500. The building power grid 400 is connected to a power grid 600 via a connecting line 410 and an electricity meter 610 with a house connection line 601. According to the invention, the energy measuring device 510 is advantageously installed in or on the connecting line 410. In the exemplary embodiment, a consumer connection line 413 is provided at a node 411, with which the energy consumer 200 is connected to the building power grid 400. The energy consumer 200 has a controller 210 and an electrical device 220. An inverter 310 is connected to the node 411 via a generator line 412. The energy generator 3200 is connected to the inverter 310.

[0030] The energy meter 510 is connected to a router 520 via a first data line 501. An internet coupler 530 is also connected to the router 520 via a second data connection 502, which is further connected to the controller 210 via a third data connection 503.

[0031] In the exemplary embodiment, a heat pump with an integrated controller 210 is shown as the energy consumer 200. The electrical device 220 of a heat pump is primarily an electric compressor, whose speed is controlled by the controller. As soon as the energy meter 510 signals a positive power output, in the sense of a power output to the power grid, thus a power output greater than a setpoint, the energy consumer 220 of the heat pump 200 is put into operation. This advantageously occurs when the power value determined by the energy meter is equal to the minimum power of the electrical device 220.

[0032] If the electrical device 220 has a minimum power A, for example 500 W, the electrical device is advantageously switched on when an excess current or an excess power of at least approximately a value A, in the example about 0.5 kW, is available.

[0033] In an advantageous embodiment, the electrical device 220 or the energy consumer 200, here the heat pump, is already switched on when a certain negative power value, which is advantageously close to zero, is reached. It may be advantageous to switch the electrical device 220 on even when a negative power value is reached, i.e., when electricity is drawn from the power grid, particularly if the forecast indicates that yields are to be expected with a time delay. This will be particularly the case when high thermal output is required immediately. In this case, it makes sense to advantageously initiate switching on even before the high electricity yields are reached.

[0034] The timing of activation depends on the setpoint. It is best to activate when the building's electrical grid can provide a minimum power equivalent to the electrical device.

[0035] However, it is also advantageous to switch on the device even if the setpoint is lower than the minimum power of the electrical device, especially if thermal power must be available immediately.

[0036] Accordingly, it is advantageous to add a demand value to the stability value. For example, if a higher room temperature or hot water temperature is suddenly requested, the demand value will be high and may exceed the stability value, affecting the sum of the stability value and the demand value. A high demand value reduces the setpoint in that the system will switch on even at a power value that is lower than the excess power generated by the energy generator.

[0037] In this example, the system would advantageously be switched on at an excess power of 200 W, even though the heat pump's compressor requires at least 500 W of power. If the setpoint drops even further or changes further due to a high demand, the energy consumer can be switched on even if electricity is already being drawn from the grid.

Claims

1. An energy management system (100) comprising a data network and a building electricity network (400), wherein an energy consumer (200) comprising an energy generator (300) is integrated into the building electricity network (400), the building electricity network (400) being connected to an electricity network via an electricity meter connected to connecting cable (410), the energy generator (300) is electrically incorporated into the building electricity network (400) via an inverter (310) via a generator cable (412), the energy consumer (200) is connected to the building electricity network (400) by an electric consumer connection (413) located between the inverter (310) and the electricity meter, wherein a controller (210) of the energy consumer (200) is connected to the data network (500), wherein an energy measuring device (510) is connected to the connecting cable (410) and the building electricity network (400) by a power measuring unit, and the energy measuring device (510) is connected to the data network by a first data connection (501), wherein the energy measuring device (510) is configured to determine the energy generated in the building electricity network (410) by the energy generator (300) minus the energy consumed in the building electricity network (400) to identify an excess of power, characterised in that the controller (210) is configured to control an electrical apparatus (220) of the energy consumer (200) dependent on a value of the excess of power, and, provided power deviating from a set value of power transmission is determined by the energy measuring device (510), to adjust the output of the energy consumer (200) such that only the exact amount of power is supplied to the energy consumer (200) at all times as the building electricity network (400) has available in excess, and wherein solely a connection via the data network exists between the energy consumer (200) connected to the building electricity network (400) and the energy measuring device (510).

2. The energy management system (100) according to claim 1, characterised in that the energy measuring device (510) is connected to an internet coupler (530), to the router (520) or the controller (210) by the first data connection (501).

3. The energy management system (100) according to claim 1 or 2, characterised in that the energy management system (100) connects the controller (210) to the internet coupler (530), the internet coupler (530) to the router (520), and the energy measuring device (510) to the router (520).

4. A method of controlling energy consumption of an electrical apparatus (220) of an energy consumer (200) in an energy management system (100) according to any of claims 1 to 3, including the method steps of: determining, in the energy measuring device (510), a power L dependent on a current S flowing through the connecting cable (410), which is available in the building electricity network (400), determining whether an excess of power fed into the building electricity network (400) from the energy generator (300) exists, and controlling the electric apparatus (220) by the controller (210) of the energy consumer (200) dependent on a value of the excess of power, and, provided a power or a current deviating from a set value of the power transmission is determined by the energy measuring device (510), adjusting the output of the energy consumer (200) such that only the exact amount of power is supplied to the energy consumer (200) at all times as the building electricity network (400) has available in excess.

5. The method of controlling energy consumption according to claim 4, including the method step of: controlling the electrical apparatus (220) by the controller (210) dependent on the value of the excess of electrical power such that at least a portion of the excess of electrical power of the building electricity network (400) is consumed by the electric apparatus (220) of the energy consumer (200).

6. The method of controlling energy consumption according to claim 4 or 5, including the method step of: operating the electric consumer (220) when electricity would be supplied from the building electricity network (400) to the electricity network, thereby at least essentially reducing or avoiding feed-in into the electricity network.

7. The method of controlling energy consumption according to claim 4, 5 or 6, including the method steps of: regulating the purchase of electricity from the electricity network or an electricity supply to the electricity network by the energy management system (100) towards zero using an available output range of the electric apparatus (220), wherein an excess of electrical power LÜ of the building electricity network (400) is delivered to the electric apparatus (220), wherein the energy consumer (200) is in particular a heat pump or an electric heating appliance, selecting the output of the energy consumer (200) such that the electricity supply to the electricity network is regulated towards zero, such that optimisation of feed-in, in particular minimising of feed-in occurs.

8. The method of controlling energy consumption according to any of claims 4 to 7, including the method steps of: determining a stability value for future yield of the energy generator (300) by an availability prediction of excess of electrical power in the energy management system (100), the availability prediction depending in particular on historical energy values having been determined in the energy measuring device (510); and / or that are determined as a prediction dependent on weather data, and specifying the output of the electric apparatus (220) dependent on a comparison of the stability value and a set stability value, such that failure-free operation of the energy consumer (200) occurs over a period of time.

9. The method of controlling energy consumption according to any of claims 4 to 8, including the method steps of: generating thermal energy by the electric consumer (200) dependent on the excess of power, in particular using reverse control, thereby achieving a set value of thermal energy or a set temperature of a heating system at an end time of a heating period, wherein, for this purpose, the electric apparatus (220) is only switched on when a point in time is reached, from which the expected excess of electrical power is sufficient to achieve the amount of thermal energy or the set temperature at the end time.