Energy management method for an energy system and energy system

Abstract

The present invention relates to an energy management method for an energy system (1) in a building. The energy system (1) comprises a plurality of uncontrollable energy consumers (HH), at least one controllable energy consumer (WP), an energy storage device (BAT), a net connection point (NAP) through which energy can be drawn from the net and/or fed into the net, and a feedback-control or control device (EMS) which is designed to feedback-control or control the at least one controllable energy consumer (WP) and the energy storage device (BAT). The plurality of uncontrollable energy consumers (HH) is configured to draw energy from the net or from the energy storage device (BAT). The method comprises the following steps: detecting a current state of charge (SOC.sub.act) of the energy store device (BAT), defining a period of time (ΔT.sub.0) during which the uncontrollable energy consumers (HH) are supplied with energy from the energy storage device, determining a limit value (SOC.sub.high) of the state of charge of the energy storage device (BAT) on the basis of a determined minimum energy demand of the plurality of uncontrollable energy consumers (HH) up to the time of charging (T.sub.0), operating the at least one controllable energy consumer (WP) with energy from the energy storage device (BAT) if the current charge state (SOC.sub.act) of the energy storage device (BAT) is greater than the determined limit value (SOC.sub.high) of the charge state and operating the at least one controllable energy consumer (WP) with energy from the net if the current charge state (SOC.sub.act) of the energy storage device (BAT) is less than or equal to the determined limit value (SOC.sub.high) of the charge state.

Claims

1. An energy management method for an energy system (1) in a building, the energy system (1) including a plurality of uncontrollable energy consumers (HH) that cannot be switched on or off by the energy management method, at least one controllable energy consumer (WP) that can be switched on and off by the energy management method, an energy storage device (BAT) having a discharge efficiency, a net connection point (NAP) through which energy can be drawn from a net and/or fed into the net, and a feedback-control or control device (EMS) designed to feedback-control or control the at least one controllable energy consumer (WP) and the energy storage device (BAT), wherein the plurality of uncontrollable energy consumers (HH) is configured to draw energy from the net or from the energy storage device (BAT), the method comprising the steps of: detecting a current state of charge (SOCact) of the energy storage device (BAT); defining a period of time (ΔT0) during which the energy storage device (BAT) cannot be charged and the plurality of uncontrollable energy consumers (HH) are supplied with energy from the energy storage device; calculating a lower limit value (SOChigh) of the state of charge of the energy storage device (BAT) by multiplying energy demand of the plurality of uncontrollable energy consumers (HH) during the specified period of time (ΔT0) by the discharge efficiency of the energy storage device (BAT); operating the at least one controllable energy consumer (WP) with energy from the energy storage device (BAT) if the current state of charge (SOCact) of the energy storage device (BAT) is greater than the determined lower limit value (SOChigh) of the state of charge; and operating the at least one controllable energy consumer (WP) with energy from the net if the current state of charge (SOCact) of the energy storage device (BAT) is less than or equal to the determined lower limit value (SOChigh) of the state of charge.

2. The method according to claim 1, wherein the at least one controllable energy consumer is a heat pump (WP).

3. The method according to claim 2, wherein the energy system (1) further comprises a photovoltaic system (PV) configured to supply energy to the energy consumers (HH, WP) and the energy storage device (BAT).

4. The method according to claim 3, wherein the energy storage device (BAT) can only be charged by the photovoltaic system (PV).

5. The method according to claim 1, wherein the energy system (1) further comprises a photovoltaic system (PV) configured to supply energy to the plurality of uncontrollable energy consumers (HH), the at least one controllable energy consumer (WP) and the energy storage device (BAT).

6. The method according to claim 5, wherein the energy storage device (BAT) can only be charged by the photovoltaic system (PV).

7. The method according to claim 5, wherein the feedback-control or control device (EMS) is connected to an internet (WWW) connection to receive a solar radiation forecast for determining energy generation by the photovoltaic system (PV).

8. The method according to claim 1, wherein the feedback-control or control device (EMS) is configured to log consumption data of the plurality of uncontrollable energy consumers (HH) in order to determine or estimate an energy demand of the plurality of uncontrollable energy consumers (HH) on the basis of the logged data.

9. The method according to claim 1, wherein the at least one controllable energy consumer (WP) is connected to the net connection point (NAP) via a separate electricity meter.

10. An energy system (1) in a building, comprising: a plurality of uncontrollable energy consumers (HH), at least one controllable energy consumer (WP), an energy storage device (BAT) having a discharge efficiency, a net connection point (NAP) through which energy can be drawn from a net and/or fed into the net, and a feedback-control or control device (EMS) designed to feedback-control or control the at least one controllable energy consumer (WP) and the energy storage device (BAT), wherein the plurality of uncontrollable energy consumers (HH) cannot be switched on or off by the feedback-control or control device, wherein the at least one controllable energy consumer (WP) can be switched on and off by the feedback-control or control device, wherein the plurality of uncontrollable energy consumers (HH) is configured to draw energy from the net or from the energy storage device (BAT), and wherein the feedback-control or control device (EMS) is configured to: detect a current state of charge (SOCact) of the energy storage device (BAT); define a period of time (ΔT0) during which the energy storage device (BAT) cannot be charged and the plurality of uncontrollable energy consumers (HH) are supplied with energy from the energy storage device; calculate a lower limit value (SOChigh) of the state of charge of the energy storage device (BAT) by multiplying energy demand of the plurality of uncontrollable energy consumers (HH) during the defined period (ΔT0) by the discharge efficiency of the energy storage device (BAT); operate the at least one controllable energy consumer (WP) with energy from the energy storage device (BAT) if the current state of charge (SOCact) of the energy storage device (BAT) is greater than the determined lower limit value (SOChigh) of the state of charge; and operate the at least one controllable energy consumer (WP) with energy from the net if the current state of charge (SOCact) of the energy storage device (BAT) is less than or equal to the determined lower limit value (SOChigh) of the state of charge.

11. The energy system (1) according to claim 10, further comprising a photovoltaic system (PV) configured to supply energy to the plurality of uncontrollable energy consumers (HH), the at least one controllable energy consumer (WP) and the energy storage device (BAT).

12. The energy system (1) according to claim 10, wherein the at least one controllable energy consumer is a heat pump (WP).

13. The energy system (1) according to claim 11, wherein the at least one controllable energy consumer is a heat pump (WP).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments are described in more detail below on the basis of an exemplary embodiment which is shown in the drawings but to which the invention is not limited.

(2) The drawings show schematically:

(3) FIG. 1 shows an energy system according to a first exemplary embodiment of the invention.

(4) FIG. 2 shows a flow chart of a second exemplary embodiment of the invention.

(5) FIG. 3 shows characteristic curves of the consumed and generated electrical power and the state of charge of the energy storage device in an energy system according to the first exemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION BY MEANS OF EXEMPLARY EMBODIMENTS

(6) In the following description of a preferred embodiment of the present invention, identical reference signs designate identical or comparable components.

(7) FIG. 1 shows a highly simplified schematic representation of a first exemplary embodiment of an energy system 1 according to the invention in a building. The illustrated energy system 1 comprises a photovoltaic system PV (hereinafter also abbreviated as PV system), which converts radiant energy from the sun 3 into electrical energy. The energy system 1 can use other renewable energy sources, such as a wind turbine, instead of a PV system or in addition to the PV system. An inverter WR converts the direct current generated by the PV system into alternating current that can be used by consumers. The thick solid lines illustrate the internal electricity net 4 of the building and dotted lines illustrate communication lines 5 for data traffic, for example for controlling, feedback-controlling and/or exchanging data with a server 2 via the Internet WWW or in an intranet or a cloud.

(8) The internal electricity net 4 of the building is connected to a public electricity net via a net connection point NAP. An electricity meter M measures the energy consumption drawn from the public net by the internal electricity net 4 and the amount of energy (or produced power integrated over time) fed into the public net by the internal electricity net 4.

(9) The energy system 1 comprises an energy storage device BAT, which can consist of batteries or rechargeable batteries, for example. The energy storage device BAT comprises an inverter that converts alternating current from the electricity net 4 into direct current to charge the energy storage device BAT. The inverter can also convert direct current from the energy storage device BAT into alternating current. In order to charge the energy storage device BAT with energy from the PV system, a direct power line can also be provided between the PV system and the energy storage device BAT, so that a conversion from direct current to alternating current and vice versa is not necessary.

(10) Another component of the energy system 1 is a heat pump WP as a controllable energy consumer. The operation of the heat pump WP can be feedback-controlled or controlled by a feedback-control or control device EMS. With an SGReady heat pump, it is also possible to have the operation of the heat pump WP controlled by an external signal from the net operator. The energy system 1 can also include other controllable energy consumers. For example, a washing machine can be controlled by the feedback-control or control unit EMS. Furthermore, a ventilation system and/or a night storage heater can be provided as controllable energy consumers.

(11) A plurality of uncontrollable energy consumers HH are connected to the internal electricity net 4 of the building. The uncontrollable energy consumers HH are, for example, household appliances that are switched on and off by a user or occupant of the building. The energy demand of the uncontrollable energy consumers HH shall preferably be covered directly by the PV system, so that the generated energy can be consumed directly without intermediate storage. Direct consumption is particularly efficient because losses due to charging and discharging the energy storage device BAT are avoided. If the output produced by the PV system is not large enough to cover the demand of the uncontrollable energy consumers HH, the uncontrollable energy consumers HH shall be supplied with energy by the energy storage system BAT. If the demand of the uncontrollable energy consumers HH cannot be met by the PV system or the energy storage device BAT, energy can also be obtained from the public net via the net connection point NAT. The more efficiently the energy system 1 is operated, the less energy has to be drawn from the public net.

(12) An electricity meter M measures the energy provided by the PV system. The heat pump WP can have a separate electricity meter M, so that energy can be obtained from the public net at a particularly favorable rate. One objective of the energy management is therefore to obtain energy from the public net preferably for the operation of the heat pump WP if the energy demand cannot be covered by the PV system. The uncontrollable energy consumers HH shall preferably be supplied with energy from the PV system or from the energy storage device BAT.

(13) The feedback-control or control device EMS is connected via communication lines 5 to the inverter WR of the PV system, to the heat pump WP, to the energy storage device BAT, to the electricity meter M at the net connection point NAP and to the internet WWW. Instead of communication lines 5, wireless communication can also be provided between the feedback-control or control device EMS and the above-mentioned components of the energy system 1.

(14) The energy system 1 can be operated in four different operating states depending on the output produced by the PV system and the state of charge of the energy storage device BAT. In all operating states, the heat pump WP can be supplied directly by the PV system, provided that sufficient output is produced by the PV system. In addition, the uncontrollable energy consumers HH shall be supplied directly by the PV system. Thus, the energy generated by the PV system shall be used directly if possible, without intermediate storage of the energy.

(15) A first operating state B1 is present if a current state of charge of the energy storage device BAT SOC.sub.act is less than a defined lower limit SOC.sub.high of the state of charge. SOC stands for “State of Charge”. The lower limit value SOC.sub.high is used to ensure that the energy storage device BAT is sufficiently charged to supply energy from the energy storage device BAT to the uncontrollable energy consumers HH after sunset and before sunrise. In the first operating state B1, the energy storage device BAT shall be charged by the PV system if possible. The heat pump WP must not be supplied by the energy storage device BAT. If possible, the uncontrollable energy consumers HH shall be supplied by the energy storage device BAT. Only when the energy storage device BAT is empty shall the uncontrollable energy consumers HH be supplied with electricity from the public net.

(16) A second operating state B2 exists if the current charge state of the energy storage device BAT SOC.sub.act is higher than the lower limit value SOC.sub.high but lower than an upper limit value SOC.sub.max. The upper limit SOC.sub.max can fulfil two different functions. On the one hand, it is used to have available sufficient capacity in the energy storage device BAT to charge the energy storage device BAT during the power peaks of the PV system so that curtailment losses can be avoided. Furthermore, the upper limit value SOC.sub.max is used to limit the loading of the energy storage device BAT to a value which is favorable for the service life of the energy storage device BAT. Certain energy storage devices BAT for electrical energy, such as batteries or rechargeable batteries, should not be charged to full capacity for very long periods of time, as this can have negative effects on the service life. If the energy consumption of the uncontrollable energy consumers HH drops drastically for several days or weeks, for example because the occupants or users of the building are on holiday, the upper limit value SOC.sub.max can be used to prevent the energy storage device from being charged to 100% during this period. For example, the upper limit value SOC.sub.max for such a period can be set to a value between 50% and 70%. Thus, with a low expected demand of the controllable energy consumers WP and the uncontrollable energy consumers HH, the loading of the energy storage device BAT can be limited to the amount of energy required to supply the energy consumers WP, HH. In the second operating state B2, the energy storage device BAT shall be charged by the PV system. Both the heat pump WP and the uncontrollable energy consumers HH may be supplied by the energy storage device BAT.

(17) The energy system 1 is operated in a third operating state B3 when the upper limit value SOC.sub.max of the state of charge is reached and the PV system does not operate at the maximum power due to cloudiness. In this state, the energy storage device BAT must not be charged by the PV system. Both the heat pump WP and the uncontrollable energy consumers HH may be supplied by the energy storage device BAT.

(18) The fourth operating state B4 occurs when the upper limit value SOC.sub.max of the state of charge is reached and the sun is shining, so that the PV system produces energy near its maximum output. In this state, the energy storage device BAT may or can no longer be charged by the PV system. Since the PV system delivers a high electrical output, the heat pump WP shall primarily be operated directly with energy from the PV system. Neither the heat pump WP nor the uncontrollable energy consumers HH may be supplied by the energy storage device BAT.

(19) An algorithm which determines the four operating states B1 to B4 by comparing the current state of charge SOC.sub.act with the defined limit values SOC.sub.max and SOC.sub.high as well as the current power produced by the PV system, is implemented in the feedback-control or control device EMS.

(20) FIG. 2 shows a flow chart of a method for an energy management according to an exemplary embodiment of the invention. The method allows an overnight reserve of an energy storage device BAT to be calculated for the power consumption in a building and to be held available accordingly in order to avoid the purchase of energy from the public net. This ensures a particularly efficient operation of a PV system. It is also possible to ensure that the service life of the energy storage device BAT remains as long as possible, since a long operation in unfavorable charge areas can be avoided by setting charge limit values.

(21) The circle on the left symbolizes a method P, which, for example, stands for the operation of an energy system in a building. The energy system can, for example, be an energy system with a PV system, an energy storage device (battery) and a heat pump WP, as described in the first exemplary embodiment. The energy management method can be carried out by a feedback-control or control device EMS, for example.

(22) With a time constant ΔT.sub.1 the method P is monitored by the feedback-control or control device EMS S1. It is thus checked whether correcting variables in the energy system 1 are observed on the basis of the operating states B1 to B4. This step S1 can be performed every second, for example.

(23) In the next step, S2, a time series is read in to determine an estimated value of the energy generation by the PV system. For example, weather data for the next 24 hours can be received as a time series via the internet. For example, if a smaller prediction horizon is used, the weather data can also only be received for the next 8 or 12 hours. The weather data can then be used to determine an estimated value of the energy production by the PV system. Important parameters of the weather data are, for example, the expected hours of sunshine, the degree of cloud cover and the position of the sun. This data can, for example, be read in as time series. The time resolution of the time series then determines the temporal resolution of the resulting temporal course of the determined energy generation. Other parameters, such as the time of sunrise and sunset, can also be stored in a memory.

(24) Accordingly, a data time series can also be read in to determine the expected energy consumption. For this purpose, a data memory with logged consumption data in the feedback-control or control device EMS can be provided. If the consumption data is stored on a server (or in the cloud), the data can be retrieved via an internet connection.

(25) Step S3 starts the energy management method, which comprises steps S4 to S10. The method can, for example, be executed on a processor of the feedback-control or control device EMS. Alternatively, the method can also be carried out on an external server accessible via the internet, so that less computing power must be available locally. Running on a server also has the advantage that a plurality of feedback-control or control devices EMS can access the method and the method can be improved or updated without the need for local corresponding action.

(26) In the first step S4, the theoretical net consumption only by uncontrollable energy consumers is calculated as a time series. This consumption is also referred to as household current. For this purpose, a time series of the electrical power demand of the uncontrollable energy consumers is calculated which exceeds the power provided by the PV system. The calculation is performed for each time step within the prediction horizon. For example, a time step can be 10 to 15 minutes long. The prediction horizon can range e.g. from 12 to 24 hours, so that it covers a complete charge and/or discharge cycle of the battery. The determined consumption is multiplied by the discharge efficiency of the battery, i.e. the energy storage device.

(27) In the second step, S5, the theoretical net consumption of all energy consumers is calculated. This includes the consumption of controllable and uncontrollable energy consumers, i.e. e.g. the consumption by a heat pump and the household electricity. The calculation is again carried out as a time series. For this purpose, a time series of the electrical power demand of all electrical consumers including the heat pump is calculated which exceeds the power provided by the PV system. The calculation is performed for each time step within the prediction horizon. The determined consumption is multiplied by the discharge efficiency of the battery, i.e. the energy storage device.

(28) In the third step of method S6, the expected surplus of the electrical power (or energy) generated by the PV system is calculated as a time series. A time series of the average excess power of the PV system (power of the PV system minus the sum of the estimated power consumed by all consumers) is calculated for each time step within the prediction horizon and multiplied by the charging efficiency of the battery so that losses occurring when charging the battery are taken into account.

(29) In the following step, S7, the minimum amount of energy to be held available in the energy storage device BAT for the household electricity is calculated as a time series. A limit value SOC.sub.high of the state of charge of the energy storage device BAT can be determined from the minimum amount of energy to be held available for the household electricity (see S9). Until the limit value SOC.sub.high of the state of charge is reached, controllable energy consumers, such as the heat pump WP, can also obtain energy from the energy storage device BAT. If the limit value SOC.sub.high is reached or is gone below, only the uncontrollable energy consumers are supplied by the energy storage device BAT.

(30) The calculation of the minimum amount of energy to be held available in the energy storage device can, for example, be performed by a backward discrete integration of the difference of the calculated time series from steps S4 and S6 from the time of the last occurrence of net consumption within the prediction horizon. The integral is here limited to energetically permissible values so that the storage capacity of the energy storage device BAT does not assume any values below 0% or above 100%. In particular, the amount of energy to be held available is determined up to a point in time T.sub.0 within the prediction horizon in which the energy storage device BAT can be recharged.

(31) For example, the period of time ΔT.sub.0 can be determined on the basis of the position of the sun, in particular on the basis of the points in time of sunset and sunrise, so that the period of time ΔT.sub.0 substantially depends on the duration of the night. For example, the period of time ΔT.sub.0 can depend on the energy generation of the PV system. In particular, the period of time ΔT.sub.0 is defined in such a way that sufficient energy is held available in the energy storage device BAT to supply the energy consumers HH with energy until the energy consumers HH can again be supplied with energy from the PV system. The limit value SOC.sub.high is therefore essentially used to ensure the energy supply of the uncontrollable energy consumers HH during a period of time in which no energy is provided by the renewable energy source, i.e. e.g. at night when a PV system cannot generate any energy.

(32) In a further step, S8, the maximum amount of energy required for the household electricity and the heat pump WP can be calculated as a time series. The calculation can, for example, be performed by a backward discrete integration of the difference of the calculated power time series from steps S5 and S6 within the prediction horizon. The integral is here limited to energetically permissible values so that the storage capacity of the energy storage device BAT does not assume any values below 0% or above 100%.

(33) In step S9, the limit value SOC.sub.high can be derived from the result of the calculation in step S7. The limit value SOC.sub.high is determined on the basis of the determined energy demand of the energy consumers during the period of time ΔT.sub.0. The limit value SOC.sub.high can be determined for each time step within the prediction horizon. In particular, the limit value SOC.sub.high can reach a minimum of 0% at the end of the ΔT.sub.0 period.

(34) In a further step, S10, an upper limit value SOC.sub.max for the charge state of the energy storage device BAT can additionally be determined on the basis of the determined course of energy generation by the PV system and/or on the basis of the expected consumption of the energy generators in the predetermined period ΔT.sub.0 as well as in the prediction horizon. On the one hand, this limit value SOC.sub.max can ensure that sufficient capacity is available during the day for the expected power peaks of the PV system when charging the energy storage device BAT, so that curtailment losses can be avoided. On the other hand, the upper limit value SOC.sub.max can be used to limit the state of charge of the energy storage device BAT to a maximum value which is favorable for its service life.

(35) The upper limit value SOC.sub.max can be calculated for each time step within the prediction horizon. For example, the upper limit value SOC.sub.max can be determined in such a way that it reaches a maximum value of 100% at sunset when no further energy production by the PV system can be expected until the next day, or a maximum value between 50% and 70% when the expected consumption of the uncontrollable energy consumers HH is so low that a permanent state of charge close to 100% shall be avoided in order not to negatively influence the service life of the energy storage device BAT.

(36) After the method was carried out with steps S4 to S10, the calculated control variables, in particular the limit values SOC.sub.high and SOC.sub.max, can be output in step S11. The entire procedure is performed cyclically at intervals of ΔT2 of e.g. 10 or 15 minutes.

(37) FIG. 3 shows a time curve of the power P.sub.PV generated by the PV system, the power P.sub.WP consumed by the heat pump WP and the power P.sub.HH consumed by the uncontrollable energy consumers (household electricity) over a prediction horizon of 24 hours.

(38) At 5:30 p.m., the output P.sub.PV generated by the PV system PV drops below the consumption P.sub.HH of the uncontrollable energy consumers. This point in time is referred to as t.sub.start in FIG. 3. From this point on, energy must be drawn from the energy storage device BAT to cover the household electricity P.sub.HH. At the point in time t.sub.start, in particular, the defined period ΔT.sub.0 begins. From approximately 6:30 p.m., i.e. after sunset, the PV system no longer delivers any power (P.sub.PV=0 W), so that the household electricity P.sub.HH must be provided completely by the energy storage device BAT.

(39) At about 6:00 a.m. the sun rises in the exemplary temporal course of the energy consumption and the energy production shown in FIG. 3. The output P.sub.PV provided by the PV system begins to rise slowly from 0 W. The point in time at which the power P.sub.PV generated by the PV system again exceeds the power P.sub.HH consumed by the uncontrollable energy consumers is referred to in FIG. 3 as t.sub.end (at about 9:00 a.m.). This point in time essentially corresponds to the end of the predetermined period ΔT.sub.0. However, this is not necessarily the point in time at which a charging process of the energy storage device BAT is started. In order to avoid curtailment losses, it can be advantageous to charge the energy storage device BAT only when there is a high excess power P.sub.PV over the consumption P.sub.HH (e.g. at noon). In the meantime, the excess power (P.sub.PV−P.sub.HH) can be fed into the public electricity net.

(40) The area below the P.sub.HH curve is a measure of the amount of energy consumed via the household electricity (by the uncontrollable energy consumers HH). In order not to have to draw any additional energy from the net until the point in time at about 9:00 a.m., the energy storage device BAT shall hold available the necessary amount of energy in stock. For this purpose, the lower limit value SOC.sub.high for the state of charge is calculated as described above. The limit value SOC.sub.high substantially results from the determined energy consumption for the household electricity P.sub.HH (area below the P.sub.HH curve) during the defined period of time ΔT.sub.0 in the prediction horizon multiplied by a discharge efficiency of the energy storage device BAT. In addition, a defined amount of energy can be stored as an emergency reserve. In this case, the limit value SOC.sub.high can be increased accordingly.

(41) In a period around midnight (12:00 p.m.), the heat pump WP (with the power consumption P.sub.WP) is operated in the exemplary power curve shown. If the current state of charge of the energy storage device BAT is above the SOC.sub.high limit value during this period, energy from the energy storage device BAT can be used to operate the heat pump WP. If the SOC.sub.high limit value is reached, or if it is gone below, the heat pump is operated with energy from the public electricity net. In particular, if the heat pump WP is connected to the public electricity net via a separate electricity meter, a particularly favorable heat pump rate can be used.

(42) If the energy demand of the household electricity P.sub.HH has been correctly determined, the state of charge of the energy storage device BAT should never fall below the limit value SOC.sub.high since it is updated and reduced accordingly at each calculation step. At the point in time t.sub.end, which substantially corresponds to the end of the predetermined period ΔT.sub.0, the limit value SOC.sub.high is at or close to 0%. The calculation can be performed every 10 or 15 minutes as described above.

(43) The features disclosed in the above description, claims and drawings can be relevant, either individually or in any combination, to realize the invention in its various embodiments.

LIST OF REFERENCE SIGNS

(44) 1 energy system

(45) 2 server

(46) 3 sun

(47) 4 internal electricity net

(48) 5 communication lines

(49) PV photovoltaic system (PV system)

(50) WP controllable energy consumer (heat pump)

(51) BAT energy storage device

(52) NAP net connection point

(53) WWW internet

(54) EMS feedback-control or control device

(55) M electricity meter

(56) WR inverter

(57) HH uncontrollable energy consumer (household appliance)