Method and controller for operating heater of hot water storage device, and hot water storage device

Abstract

Method for operating a hot water storage device (10) comprising a tank (11), a heating unit (15), at least one temperature sensor (19, 20) and a controller (21) for controlling the heating unit (15). The method comprises the step of determining a water usage profile from a water temperature measurement signal provided by at least one temperature sensor (19, 20), said water usage profile providing a nominal temperature and a nominal volume of the heated water to be stored in the tank for a defined time interval in a day and / or a defined day in a week. The heating unit (15) is operated in such a way that, for each defined time interval in a day and / or each defined day in a week, the actual temperature and the actual volume of the heated water stored in the tank automatically correspond to the respective nominal values of the water usage curve.

Description

Technical Field

[0001] The present disclosure relates to a method for operating a hot water storage device. In addition, the present disclosure relates to a controller for operating a hot water storage device and a hot water storage device. Background Art

[0002] A hot water storage device known in the prior art comprises a tank configured to store water, wherein the tank has a bottom wall, a top wall and a side wall extending between the bottom wall and the top wall. The hot water storage device known in the prior art further comprises a heating unit located at a first distance from the bottom wall, wherein the heating unit is configured to heat the water stored in the tank, i.e. in such a way that the water heated by the heating unit rises in the tank so that the heated water is layered above the unheated water in the tank. The hot water storage device known in the prior art further comprises a temperature sensor located at a certain distance from the bottom wall, the temperature sensor being configured to measure the water temperature of the heated water. The hot water storage device known in the prior art further comprises a controller configured to control the heating unit and thereby control the water temperature of the heated water stored in the tank. When the water temperature in the tank falls below a corresponding threshold, the water in the tank may be started to be heated.

[0003] GB 2 518 365 A, US 2009 / 0 188 486 A1, US 11 060 763 B2, US 10 295 199 B2 and US 7 971 796 B2 disclose hot water storage devices.

[0004] Controllers of hot water storage devices known in the prior art permanently maintain a defined volume of water in a tank of the hot water storage device at a defined hot water temperature, either 24 hours a day and 7 days a week, or according to a daily on / off schedule of the hot water storage device when the hot water storage device is in an on state. Permanently maintaining a defined volume of water in a tank of the hot water storage device at a defined hot water temperature is energy inefficient and generates carbon emissions when there is no actual demand for hot water. Summary of the invention

[0005] In this context, a novel method of operating a hot water storage device as defined in claim 1, a novel controller for a hot water storage device as defined in claim 13 and a novel hot water storage device as defined in claim 15 are provided, which allow the hot water storage device to be operated efficiently with energy with lower carbon emissions.

[0006] The method according to claim 1 determines a water usage curve based on a water temperature measurement signal provided by at least one temperature sensor, which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for defined time intervals of the day and / or defined days of the week.

[0007] The method according to claim 1 operates the heating unit in such a way that for each defined time interval of the day and / or each defined day of the week the actual temperature and the actual volume of the heated water stored in the tank automatically correspond to the corresponding nominal values ​​of the water usage curve.

[0008] According to a first alternative, at least one water temperature measurement signal provided by at least one temperature sensor is provided to a database, such as a cloud database, wherein the database determines a water usage curve which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for each respective time interval of a respective day of the week, and wherein the controller operates the heating unit based on said water usage curve provided to the controller by the database. In the first alternative, the functionality of the method is split between the database and the controller.

[0009] According to a second alternative, at least one water temperature measurement signal provided by at least one temperature sensor is provided to a controller, wherein the controller determines a water usage curve which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for each respective time interval of respective days of the week, and wherein the controller operates the heating unit based on the water usage curve. In the second alternative, the functionality of the method is provided solely by the controller.

[0010] The controller of the hot water storage device according to claim 13 is configured to determine a water usage curve based on a water temperature measurement signal provided by at least one temperature sensor of the hot water storage device, the water usage curve providing a nominal temperature and a nominal volume of heated water to be stored in the tank for defined time intervals of the day and / or defined days of the week.

[0011] The controller of the hot water storage device according to claim 13 is configured to operate the heating unit of the hot water storage device in such a way that, for each defined time interval of the day and / or each defined day of the week, the actual temperature and the actual volume of heated water stored in the tank of the hot water storage device automatically correspond to the corresponding nominal values ​​of the water usage curve.

[0012] The method and controller of the hot water storage device according to the present disclosure allow for energy efficient operation of the hot water storage device with lower carbon emissions. The water usage curve is determined based on the water temperature measurement signal provided by at least one temperature sensor. The water usage curve provides a nominal temperature and a nominal volume of heated water stored in the tank for each corresponding time interval of the day and each corresponding day of the week. Therefore, the water usage curve provides not only a nominal value for the water temperature, but also a nominal value for the volume of heated water to be stored in the tank.

[0013] Preferably, the water usage curve is determined based on a first water temperature measurement signal provided by a first temperature sensor located at a second distance from the bottom wall of the storage tank and a second water temperature measurement signal provided by a second temperature sensor located at a third distance from the bottom wall of the storage tank and / or based on an average water temperature signal of the first water temperature measurement signal and the second water temperature measurement signal, wherein the second distance is greater than the first distance, and the third distance is greater than the second distance. This allows for more accurate control of the temperature and volume of the heated water in the storage tank, thereby providing energy efficient operation of the hot water storage device with lower carbon emissions.

[0014] Preferably, the water consumption curve is determined based on the rate of change of at least one water temperature measurement signal within a corresponding time interval of the corresponding day and / or based on the frequency and based on the hot water demand within a corresponding time interval of the corresponding day. This allows the water consumption curve to be determined in a reliable and simple manner.

[0015] Preferably, the water consumption curve is determined in such a way that for each respective time interval of each respective day of the week, a nominal value pair comprising a nominal temperature and a nominal volume of the heated water to be stored in the tank is determined, i.e. a nominal value pair N in a group of nominal value pairs, the nominal value pairs comprising at least the following nominal value pairs: pair 1: first nominal volume and first nominal temperature, pair 2: first nominal volume and second nominal temperature, pair 3: second nominal volume and first nominal temperature, pair 4: second nominal volume and second nominal temperature, wherein the second nominal volume is greater than the first nominal volume, and wherein the second nominal temperature is greater than the first nominal temperature. The group of nominal value pairs, based on which the water consumption curve for each respective time interval of each respective day of the week is determined, may comprise the following additional nominal value pair: pair 5: third volume and second nominal temperature, wherein the third nominal volume is greater than the second nominal volume. The set of nominal value pairs (based on which the water usage for each time interval for each corresponding day of the week is determined) may include the following additional nominal value pairs: Pair 0: a fourth volume and a fourth nominal temperature, wherein the fourth nominal volume is less than the first nominal volume and the fourth nominal temperature is less than the first nominal temperature. Pair 0 may correspond to an off state or a standby state of the hot water storage device 10. Pairs 1 to 5 all belong to an on state of the hot water storage device 10. For pairs 1 to 4, the corresponding volume of heated water is stratified above the unheated water in the tank. For pair 5, the tank may be destratified so that the entire volume of the tank is filled with heated water. This allows the operation of the hot water storage device to be simple, reliable, and energy-efficient with lower carbon emissions using a limited number of nominal value pairs to define the nominal temperature and the nominal volume of heated water to be stored in the tank.

[0016] Preferably, for each respective time interval of each respective day, a confidence factor is determined in relation to the nominal temperature and the nominal volume of heated water to be stored in the tank, wherein the confidence factor depends on the amount and frequency of the hot water demand in the respective time interval of the respective day. Based on the confidence factor, the nominal value pair for the operation of the hot water storage device can be changed.

[0017] Preferably, if the amount of hot water demand and / or the frequency of hot water demand in the corresponding time interval is higher than the corresponding upper threshold value in the corresponding time interval of the corresponding day, the confidence factor of the corresponding time interval is increased. If the amount of hot water demand and / or the frequency of hot water demand in the corresponding time interval is lower than the corresponding lower threshold value in the corresponding time interval of the corresponding day, the confidence factor of the corresponding time interval is reduced. If the amount of hot water demand and / or the frequency of hot water demand in the corresponding time interval is higher than the corresponding lower threshold value and lower than the corresponding upper threshold value, the confidence factor of the corresponding time interval remains unchanged. A change in the confidence factor of the corresponding time interval of the corresponding day may affect the confidence factors of time intervals adjacent to the corresponding time interval in which the confidence factor changes. Such a confidence factor allows a simple and reliable change of the nominal value pair used in the corresponding time interval to control the temperature and volume of heated water stored in the tank of the hot water storage device, and provides energy efficient operation of the hot water storage device with lower carbon emissions.

[0018] Preferably, in an initial state or initialization state of the hot water storage device, the water consumption curve for each time interval of each day is initialized with pair N (N=2 or 3 or 4), preferably pair 4, of the nominal value pairs. If the confidence factor of the corresponding time interval of the corresponding day is below a lower limit, the water consumption curve for the corresponding time is changed to pair N-1 of the nominal value pair. If the confidence factor of the corresponding time interval of the corresponding day is above an upper limit, the water consumption curve for the corresponding time interval is changed to pair N+1 of the nominal value pair. If the confidence factor of the corresponding time interval of the corresponding day is above the lower limit and below the upper limit, the water consumption curve for the corresponding time interval remains at pair N of the nominal value pair. This allows a simple and reliable change of the nominal value pair used in the corresponding time interval to control the temperature and volume of the water heated in the tank, thereby providing energy efficient operation of the hot water storage device with lower carbon emissions.

[0019] Furthermore, there is provided a hot water storage device as defined in claim 15 having such a controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Preferred developments of the invention are provided by the dependent claims and the following description. An exemplary embodiment is explained in more detail based on the drawings, in which:

[0021] Figure 1 shows a schematic block diagram of a hot water storage device having a storage tank, a heating unit, a temperature sensor and a controller,

[0022] Figure 2 Shows the tank of a hot water storage device under different conditions.

[0023] Figure 3 shows the details of the water use curve for the same time interval,

[0024] Figure 4 A time diagram is shown to illustrate some details of how the water use curve is determined. DETAILED DESCRIPTION

[0025] Figure 1 A hot water storage device 10 is shown. The hot water storage device 10 comprises a tank 11 configured to store water. The tank 11 of the hot water storage device 10 has a bottom wall 12, a top wall 13 and a side wall 14 extending between the bottom wall 12 and the top wall 13.

[0026] The hot water storage device 10 further comprises a heating unit 15, which is located at a first distance from the bottom wall 12 of the tank 11. The heating unit 15 is configured to heat the water stored in the tank 11 in such a way that the water heated by the heating unit 15 rises in the tank 11 so that the heated water is layered above the unheated water in the tank 11.

[0027] Figure 1 A conduit 16 is shown, through which heated water can be taken from the tank 11 in order to provide the heated water to a hot water user 17. The conduit 16 is connected to the top wall 13 or to a side wall 14 adjacent to the top wall 13. Figure 1 Also shown is a duct 18, through which unheated water can be supplied to the tank 11 to replace the volume of water removed from the tank 11 via the duct 16. The duct 18 is connected to the bottom wall 12 or to the side wall 14 adjacent to the bottom wall 12.

[0028] The hot water storage device 10 further comprises at least one temperature sensor 19 , 20 which is located at a distance from the bottom wall 12 , wherein the at least one temperature sensor 19 , 20 is configured to measure the water temperature of the heated water stored in the tank 11 .

[0029] exist Figure 1 In the preferred embodiment shown in , the hot water storage device 10 comprises a first temperature sensor 19, which is located at a second distance from the bottom wall 12 of the storage tank 11, the second distance being greater than the first distance, and a second temperature sensor 20, which is located at a third distance from the bottom wall 12 of the storage tank 11, the third distance being greater than the second distance. Both temperature sensors 19, 20 are assigned to the side wall 14 of the storage tank. Both temperature sensors 19, 20 are configured to measure the water temperature of the heated water stored in the storage tank 11.

[0030] The hot water storage device 10 further includes a controller 21. The controller 21 is configured to control the heating unit 15, and thereby control the water temperature of the water stored in the tank 11.

[0031] The controller 21 provides a control signal to the heating unit 15 to control the operation of the heating unit 15 of the hot water storage device 10 .

[0032] The controller 21 is configured to receive corresponding water temperature measurement signals from the corresponding temperature sensors 19 , 20 .

[0033] Figure 1 Also shown is an optional recirculation pipe 22 extending between the pipe 16 and the tank 11. A pump 23 is assigned to the recirculation pipe 22. The pump 23 and the recirculation pipe 22 can be used to recirculate heated water taken from the tank 11 through the tank 11. The recirculation pipe 22 is connected to the bottom wall 12 or to a side wall 14 adjacent to the bottom wall 12. With the pump 23, the water in the tank 11 can be destratified.

[0034] Controllers of hot water storage devices known in the prior art permanently maintain a defined volume of water in a tank of the hot water storage device at a defined hot water temperature, either 24 hours a day and 7 days a week, or according to a daily on / off schedule of the hot water storage device when the hot water storage device is in an on state. Permanently maintaining a defined volume of water in a tank of the hot water storage device at a defined hot water temperature is energy inefficient and generates carbon emissions when there is no actual demand for hot water.

[0035] According to the present disclosure, the controller 21 of the hot water storage device 10 is configured to determine a water usage curve based on the water temperature measurement signal provided by at least one temperature sensor 19, 22, which provides a nominal temperature and a nominal volume of heated water to be stored in the tank 11 of the hot water storage device 10 for defined time intervals of a day and / or defined days of a week.

[0036] Preferably, the controller 21 is configured to determine a water usage curve based on a first water temperature measurement signal provided by the first temperature sensor 19 and a second water temperature measurement signal provided by the second temperature sensor 20 and / or an average water temperature signal of the first water temperature measurement signal and the second water temperature measurement signal, the water usage curve providing a nominal temperature and a nominal volume of heated water to be stored in the storage tank 11 of the hot water storage device 10 for a defined time interval of a day and / or a defined day of a week.

[0037] The controller 21 according to the present disclosure is configured to operate the heating unit 15 of the hot water storage device 10 in such a way that, for each defined time interval of a day and / or each defined day of a week, the actual temperature and the actual volume of the heated water stored in the tank 11 of the hot water storage device 10 automatically correspond to the corresponding nominal values ​​of the water usage curve.

[0038] The controller 21 of the hot water storage device 10 according to the present disclosure allows for energy efficient operation of the water storage device with lower carbon emissions.

[0039] If the controller 21 is configured to determine a water usage curve, the functionality of the present disclosure is only provided by the controller 21. In this case, at least one water temperature measurement signal provided by the at least one temperature sensor 19, 20 is provided to the controller 21, wherein the controller 21 determines a water usage curve which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for each respective defined time interval of a respective day of the week, and wherein the controller 21 operates the heating unit 15 based on said water usage curve.

[0040] Alternatively, the functionality of the present disclosure may be split between the controller 21 and a database 24, such as a cloud database. In this alternative, at least one water temperature measurement signal provided by at least one temperature sensor 19, 20 is preferably provided to the database 24 via the controller 21, wherein the database 24 determines a water usage curve which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for each respective defined time interval on a respective day of the week, and wherein the controller 21 operates the heating unit 15 based on said water usage curve provided to the controller 21 by the database 24.

[0041] Figure 2 The tank 11 is shown under different conditions that may be provided using the method and controller 21 of the present disclosure.

[0042] exist Figure 2 In condition I, the tank 11 stores a first volume V1 of heated water, which is layered above the unheated water in the tank 11. Figure 2 In condition I, volume V1 has a size such that the first lower temperature sensor 19 measures the temperature of unheated water and the second higher temperature sensor 20 measures the temperature of heated water. The second higher temperature sensor 20 measures the temperature of the heated water of volume V1 in the lower part of volume V1, which is preferably adjacent to or abutting the lower boundary surface of volume V1. Figure 2 In condition I, the heated water present in the first volume V1 may have a first relatively low temperature T1, such as 45°C, or a second relatively high temperature T2, such as 60°C.

[0043] exist Figure 2 In condition II, the tank 11 stores a second volume V2 of heated water, which is layered above the unheated water in the tank 11. The second volume is greater than the first volume. Figure 2In condition II, volume V2 has a size such that both the first lower temperature sensor 19 and the second higher temperature sensor 20 measure the temperature of the heated water. The first lower temperature sensor 19 measures the temperature of the heated water of volume V2 in the lower part of volume V2, which is preferably adjacent to or abutting the lower boundary surface of volume V2. Figure 2 In condition II, the heated water present in the first volume V2 may have a first relatively low temperature T1, such as 45°C, or a second relatively high temperature T2, such as 60°C.

[0044] exist Figure 2 In both conditions I and II, heated water of respective volumes V1 , V2 is stratified above unheated water in the tank 11 .

[0045] exist Figure 2 In condition III, the tank 11 stores a third volume V3 of heated water, which occupies the entire volume of the tank 11. Figure 2 In condition III, there is no unheated water in the storage tank 11, and the storage tank 11 is not stratified. Figure 2 In condition III, both the first lower temperature sensor 19 and the second higher temperature sensor 20 measure the temperature of the heated water. Figure 2 In condition III, the heated water present in the first volume V3 has a second relatively high temperature T2, for example 60°C.

[0046] According to the above combination of the volume V1, V2, V3 and the temperature T1, T2 of the heated water in the tank 11, the tank 11 may have different states if the hot water storage device 10 is in the open state.

[0047] The controller 21 of the hot water storage device 10 can be configured to determine the water usage curve according to the change rate of at least one water temperature measurement signal in the corresponding time interval of the corresponding day. The controller 21 can also be configured to determine the water usage curve according to the hot water demand in the corresponding time interval of the corresponding day and according to the frequency.

[0048] The controller 21 of the hot water storage device 10 may be configured to determine the water usage curve in such a way that, for each respective time interval for each respective day of the week, a nominal value pair comprising a nominal temperature and a nominal volume of the heated water to be stored in the tank 11 is determined, i.e. a nominal value pair in the set of nominal value pairs, comprising at least:

[0049] Pair 1: first nominal volume and first nominal temperature.

[0050] Pair 2: First nominal volume and second nominal temperature.

[0051] Pair 3: Second nominal volume and first nominal temperature.

[0052] Pair 4: Second nominal volume and second nominal temperature.

[0053] The second nominal volume of heated water to be stored in tank 11 is greater than the first nominal volume of heated water to be stored in tank 11. The second nominal temperature of heated water to be stored in tank 11 is greater than the first nominal temperature of heated water to be stored in tank 11.

[0054] Pairs 1 and 2 can be used to provide Figure 2 Condition I, that is, pair 1 is heated water of a first volume V1 having a first temperature T1, and pair 2 is heated water of a first volume V1 having a second temperature T2.

[0055] Pairs 3 and 4 can be used to provide Figure 2 Condition II, that is, pair 3 is heated water of the second volume V2 having a first temperature T1, and pair 4 is heated water of the second volume V2 having a second temperature T2.

[0056] The nominal value pairs based on which the water consumption curve for each respective time interval for each respective day of the week is determined may include the following additional nominal value pairs:

[0057] Pair 5: Third nominal volume and second nominal temperature.

[0058] The third nominal volume is greater than the second nominal volume.

[0059] Pair 5 can be used to provide Figure 2 Condition III, namely heated water of the third volume V3 having the second temperature T2.

[0060] The second nominal volume and thus the second volume V2 is greater than the first nominal volume and thus the first volume V1. The ratio R2 / 1 between the second nominal volume and thus the second volume V2 and the first nominal volume and thus the first volume V1 can be 2:1 to 4:1, preferably 2.5:1 to 3.5:1. The third nominal volume and thus the third volume V3 is greater than the first and second nominal volumes and thus the first volume V1 and the second volume V2. The ratio R3 / 1 between the third nominal volume and thus the third volume V3 and the first nominal volume and thus the first volume V1 can be 3:1 to 5:1, preferably 3.5:1 to 4.5:1. In any case, the ratio R3 / 1 is greater than the ratio R2 / 1. In one embodiment, the ratio R2 / 1 can be 3:1 and the ratio R3 / 1 can be 4:1. These ratios are of an exemplary nature.

[0061] The nominal value pairs based on which the water consumption curve for each respective time interval for each respective day of the week is determined may include the following additional nominal value pairs:

[0062] For 0: fourth nominal volume and fourth nominal temperature.

[0063] The fourth nominal volume is less than the first nominal volume, and the fourth nominal temperature is less than the first nominal temperature.

[0064] The pair 0 can be used to provide a sixth state of the hot water storage device 10 , which preferably corresponds to a closed state or a standby state of the hot water storage device 10 , in which no heated water is stored in the storage tank 11 of the hot water storage device 10 .

[0065] Water usage curves based on nominal value pairs may also be determined from the database 24 .

[0066] The controller 21 of the hot water storage device 10 may be configured to determine, for each respective time interval in each respective day, a confidence factor associated with the nominal temperature and the nominal volume of heated water to be stored in the tank 11 .

[0067] The confidence factor depends on the hot water demand and the frequency in the respective time intervals in the respective days. The hot water demand corresponds to the duration of the hot water demand or the volume of heated water taken from the tank 11 in connection with the respective hot water demand. The hot water demand can be determined based on the time required to replace the heated water taken from the tank, i.e. to restore the thermal volume and temperature of the water in the tank according to the nominal volume and nominal temperature.

[0068] The controller 21 of the hot water storage device 10 is configured to increase the confidence factor of the corresponding time interval if the hot water demand frequency and / or the hot water demand amount within the corresponding time interval is higher than the corresponding upper threshold value.

[0069] The controller 21 of the hot water storage device 10 is configured to reduce the confidence factor of the corresponding time interval if the hot water demand frequency and / or the hot water demand amount within the corresponding time interval is below the corresponding lower threshold value.

[0070] The controller 21 of the hot water storage device 10 is configured to keep the confidence factor of the corresponding time interval unchanged if the hot water demand frequency and / or the hot water demand amount in the corresponding time interval is higher than the corresponding lower threshold and lower than the corresponding upper threshold.

[0071] Confidence factors for corresponding time intervals may also be determined by database 24 .

[0072] A change in the confidence factor of a corresponding time interval of a corresponding day may affect the confidence factors of time intervals adjacent to the corresponding time interval in which the confidence factor changes based on the weighting factor. For example, if the confidence factor of a time interval may change by 10%, the confidence factors of time intervals adjacent to the corresponding time interval may change by 5% if a 50% weighting factor is used, or may change by 2.5% if a 25% weighting factor is used.

[0073] In the initial state or initialization state of the hot water storage device 10, the water consumption curve for each time interval in each day is initialized with a pair N (N=2 or 3 or 4) of the nominal value pairs. Preferably, the water consumption curve for each time interval in each day is initialized with a pair 4, which means that for each time interval of each day, the controller 21 will use the second nominal volume and the second nominal temperature to control the volume and temperature of the heated water in the storage tank 11.

[0074] During operation of the hot water storage device 10, as described above, the confidence factor is determined based on the amount of hot water demand in the corresponding time interval in the corresponding day and based on the frequency. This amount depends on the rate of change of the corresponding water temperature measurement signal and preferably on the time to restore the heated water in the tank 11 based on the nominal volume and nominal temperature.

[0075] If the confidence factor for the corresponding time interval for the corresponding day is below the lower limit, the water usage curve for the time interval is changed from pair N to pair N-1. In other words, if the initialized nominal value pair or the actual nominal value pair for the corresponding time interval is pair 3, but the confidence factor for the corresponding time interval is below the lower limit, pair 2 is used as the new nominal value pair for the corresponding time interval. If no pair N-1 is available, the actual pair is preferably left unchanged. There may be a factor in the above learning algorithm that provides time-based decay or forgetting. This will allow the confidence factor to decrease over time if there is no water use within a certain time range. The rate of memory loss caused by such decay or forgetting may depend on the implementation of the hot water storage device 10 in the field.

[0076] If the confidence factor of the corresponding time interval of the corresponding day is above the upper limit, the water consumption curve of the time interval is changed from pair N to pair N + 1. In other words, if the initialized nominal value pair or the actual nominal value pair of the corresponding time interval is pair 4, but the confidence factor of the corresponding time interval is above the upper limit, pair 5 is used as the new nominal value pair for the corresponding time interval. If there is no pair N + 1 available, the actual pair remains unchanged.

[0077] If the confidence factor of the corresponding time interval of the corresponding day is above the lower limit and below the upper limit, the water use curve of the time interval remains at pair N. In other words, if the initialized nominal value pair or the actual nominal value pair of the corresponding time interval is pair 5, and the confidence factor of the corresponding time interval of the corresponding day is above the lower limit and below the upper limit, pair 5 remains unchanged as the nominal value pair for the corresponding time interval.

[0078] Figure 3 Details of the water usage curve 30 are shown for six individual time intervals 31 of the water usage curve 30. Figure 3 In , each time interval has a duration of 15 minutes. The time interval 31 may have a duration longer or shorter than 15 minutes. Figure 3 Also shown for each time interval 31 are pairs 32 of actual nominal values, which define the nominal temperature and the nominal volume of heated water to be stored in the tank 11. Pair 3 is valid for time intervals 31a, 31b. Pair 5 is valid for time intervals 31c, 31d, 31e. Pair 4 is valid for time interval 31c. Figure 3 Also shown are the actual confidence factors 33 determined for each time interval 31. For time interval 31a, a confidence factor of 30% has been determined, which may result in a subsequent change in pair 2 for time interval 31a. For time interval 31f, a confidence factor of 90% has been determined, which may result in a subsequent change in pair 5 for time interval 31f.

[0079] Figure 4 An average water temperature signal 40 determined from the first and second water temperature measurement signals provided by the first and second temperature sensors 19, 20 is shown. At times t1, t2, the respective rates of change of the average water temperature signal 40 are relatively small, but higher than the rate of change caused by heat loss from the storage tank 11. This is determined as a relatively small amount of hot water demand in the respective time interval of the respective day. At time t3, the respective rate of change of the average water temperature signal 40 is relatively high. This is determined as a relatively large amount of hot water demand in the respective time interval of the respective day. Based on the amount and frequency of such water demands, a confidence factor 33 is determined for each time interval 31. The amount of water demand can be determined based on the time required to restore the water in the storage tank according to the nominal volume and nominal temperature.

[0080] The controller 21 defines the temperature and volume of the heated water in the tank 11 of the water storage device based on the determined water usage curve. At peak demand (corresponding to the nominal value pair 5), the entire volume V3 of the water in the tank 11 is heated to a temperature T2 using the pump 23. This state raises the thermal energy stored in the tank 11 above the normal maximum capacity of the tank 11. This state may be triggered by external factors (e.g. energy rates communicated from the cloud).

[0081] In time intervals when the demand for hot water is small, a smaller volume V1 at the first temperature T1 is sufficient (corresponding to the nominal value 1). The hot water storage device 10 minimizes the energy required to heat the water and minimizes heat losses over time and energy-inefficient operation of the hot water storage device 10. The hot water storage device 10 can be operated very energy-efficiently with a low carbon footprint. Based on the detected water consumption affecting the confidence factor 33 (see Figure 4 ), a learning pattern of nominal value pairs 32 is established, which is used to operate the hot water storage device 10 over time.

[0082] In an initial state or initialization state of the controller 21, the nominal value pair 32 for each time interval is preferably selected such that the hot water storage device 10 is operated at full capacity by the controller 21. The controller 21 may individually adjust the nominal value pair 32 for each time interval 31 based on a confidence factor.

[0083] Reference Symbols List

[0084] 10 Hot water storage device

[0085] 11 Tank

[0086] 12 bottom wall

[0087] 13 Top wall

[0088] 14 Sidewall

[0089] 15 Heating unit

[0090] 16 Pipe

[0091] 17 Hot water users

[0092] 18 Pipe

[0093] 19 Temperature Sensor

[0094] 20 Temperature Sensor

[0095] 21 Controller

[0096] 22 Recirculation pipe

[0097] 23 Pump

[0098] 24 Database

[0099] 30 Water usage curve

[0100] 31 Time interval

[0101] 32 Nominal value pairs

[0102] 33 Confidence Factor

[0103] 40 Average water temperature signal

Claims

1. A method for operating a hot water storage device (10), the hot water storage device (10) comprising: a storage tank (11) configured to store water; a heating unit (15) positioned at a first distance from the bottom wall (12) of the tank (11), the heating unit (15) being configured to heat water stored in the tank (11) so that the heated water rises in the tank (11) and is stratified above unheated water in the tank (11); at least one temperature sensor (19, 20) positioned at a distance from the bottom wall (12) of the tank (11) greater than the first distance; a controller (21) configured to control the heating unit (15), It is characterized by the following steps: determining a water usage curve based on the water temperature measurement signal provided by the at least one temperature sensor (19, 20), the water usage curve providing a nominal temperature and a nominal volume of heated water to be stored in the tank for defined time intervals of the day and / or defined days of the week, The heating unit (15) is operated in such a way that, for each defined time interval of the day and / or each defined day of the week, the actual temperature and the actual volume of heated water stored in the tank automatically correspond to the corresponding nominal values ​​of the water usage curve.

2. The method according to claim 1, wherein The hot water storage device (10) comprises a first temperature sensor (19) located at a second distance from a bottom wall (12) of the storage tank (11) and a second temperature sensor (20) located at a third distance from the bottom wall (12) of the storage tank (11), the second distance being greater than the first distance, and the third distance being greater than the second distance, The water usage curve is determined based on a first water temperature measurement signal provided by the first temperature sensor (19), a second water temperature measurement signal provided by the second temperature sensor (20), and / or an average water temperature signal of the first and second water temperature measurement signals.

3. The method according to claim 1 or 2, wherein: The water usage curve is determined based on the rate of change of the corresponding water temperature measurement signal within the corresponding time interval of the corresponding day.

4. The method according to any one of claims 1 to 3, wherein: The water usage curve is determined based on the amount and frequency of hot water demand in corresponding time intervals on corresponding days.

5. The method according to any one of claims 1 to 4, wherein: The water consumption curve is determined in such a way that for each respective time interval for each respective day of the week a nominal value pair is determined comprising a nominal temperature and a nominal volume of heated water to be stored in the tank, i.e. the nominal value pair in the set of nominal value pairs comprises at least: Pair 1: first nominal volume and first nominal temperature, Pair 2: First nominal volume and second nominal temperature, Pair 3: Second nominal volume and first nominal temperature, For 4: second nominal volume and second nominal temperature, wherein the second nominal volume is greater than the first nominal volume, Wherein, the second nominal temperature is greater than the first nominal temperature.

6. The method according to claim 5, wherein: The water consumption curve for each respective time interval for each respective day of the week is determined based on the set of nominal value pairs, the set of nominal value pairs comprising the following additional nominal value pairs: For 5: a third nominal volume and a second nominal temperature, and / or For 0: fourth nominal volume and fourth nominal temperature, Wherein, the third nominal volume is greater than the second nominal volume Wherein, the fourth nominal volume is smaller than the first nominal volume, and the fourth nominal temperature is smaller than the first nominal temperature.

7. The method according to any one of claims 4 to 7, comprising the step of determining, for each respective time interval for each respective day, a confidence factor associated with the nominal temperature and the nominal volume of the heated water to be stored in the tank, wherein The confidence factor depends on the frequency and amount of hot water demand within the respective time interval on the respective day.

8. The method according to claim 8, wherein: If the frequency of hot water demand and / or the amount of hot water demand is above a respective upper threshold value within a respective time interval on a respective day, the confidence factor is increased, If the frequency of hot water demand and / or the amount of hot water demand is below a corresponding lower threshold value within a corresponding time interval on a corresponding day, the confidence factor is reduced, If the frequency of hot water requests and / or the amount of hot water requests is above a respective lower threshold value and below a respective upper threshold value, the confidence factor remains unchanged.

9. The method according to any one of claims 7 to 8, wherein: In the initial state or initialization state of the hot water storage device (10), a water consumption curve for each time interval of each day of the week is initialized using a pair N (N=2 or 3 or 4) of the nominal value pairs, If the confidence factor of the corresponding time interval of the corresponding day is below the lower limit, the water usage curve becomes the pair N-1 of the nominal value pairs, If the confidence factor of the corresponding time interval of the corresponding day is above the upper limit, the water usage curve becomes the pair N+1 of the nominal value pairs, If the confidence factor for the corresponding time interval for the corresponding day is above the lower limit and below the upper limit, the water usage curve remains for pair N of the nominal value pairs.

10. The method according to any one of claims 8 to 9, wherein: A change in the confidence factor of a corresponding time interval of a corresponding day affects the confidence factors of time intervals adjacent to the corresponding time interval in which the confidence factor has changed.

11. The method according to any one of claims 1 to 10, wherein: At least one water temperature measurement signal provided by the at least one temperature sensor (19, 20) is provided to a database (24), such as a cloud database, wherein the database (24) determines the water usage curve, which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for each respective defined time interval on a respective day of the week, and wherein the controller (21) operates the heating unit (15) based on the water usage curve provided to the controller (21) by the database (24).

12. The method according to any one of claims 1 to 10, wherein: At least one water temperature measurement signal provided by the at least one temperature sensor (19, 20) is provided to the controller (21), wherein the controller (21) determines the water usage curve which provides a nominal temperature and a nominal volume of heated water to be stored in the tank for each respective defined time interval on a respective day of the week, and wherein the controller (21) operates the heating unit (15) based on the water usage curve.

13. A controller (21) for a hot water storage device (10), The hot water storage device (10) comprises a tank (11) configured to store water, a heating unit (15) located at a first distance from the bottom wall (12) of the tank (11), at least one temperature sensor (19, 20) located at a distance from the bottom wall (12) of the tank (11), said distance being greater than said first distance, in, The controller (21) is configured to control the heating unit (15) and thereby control the water temperature of the water stored in the tank (11). wherein the controller (21) is configured to determine a water usage curve based on the water temperature measurement signal provided by the at least one temperature sensor (19, 20), the water usage curve providing a nominal temperature and a nominal volume of heated water to be stored in the tank for defined time intervals of the day and / or defined days of the week, The controller (21) is configured to operate the heating unit (15) in such a way that, for each defined time interval of the day and / or each defined day of the week, the actual temperature and the actual volume of the heated water stored in the tank automatically correspond to the corresponding nominal values ​​of the water usage curve.

14. The controller (21) according to claim 13, wherein: The controller is configured to automatically perform the method according to any one of claims 1-12.

15. A hot water storage device (10), comprising: A storage tank (11) configured to store water, the storage tank (11) having a bottom wall (12), a top wall (13) and a side wall (14) extending between the bottom wall (12) and the top wall (13); a heating unit (15) located at a first distance from the bottom wall (12), the heating unit (15) being configured to heat water stored in the tank (11) in such a way that water heated by the heating unit (15) rises in the tank (11) so that hot water is stratified above unheated water in the tank (11); at least one temperature sensor (19, 20) located at a distance from the bottom wall (12), the at least one temperature sensor (19, 20) being configured to measure the water temperature of the heated water; A controller (21) according to any one of claims 13 to 14.

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