Method and controller to operate a hot water storage device heater and hot water storage device

Abstract

Method to operate 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) to control the heating unit (15). The method comprises the following steps: Determine from a water temperature measurement signal provided by the at least one temperature sensor (19, 20) a water usage profile, said water usage profile providing for defined time intervals of a day and/or for defined days of a week a nominal temperature and a nominal volume of the heated water to be stored within the tank. Operate the heating unit (15) in such a manner that for each defined time interval of a day and/or for each defined day of a week the actual temperature and the actual volume of the heated water stored withing the tank corresponds automatically to the respective nominal value of the water usage profile.

1 . A method to operate a hot water storage device, the hot water storage device including:
 a tank configured to store water,   a heating unit positioned at a first distance from a bottom wall of the tank, the heating unit being configured to heat the water stored within the tank such that heated water rises up within the tank and is stratified above unheated water within the tank,   at least one temperature sensor positioned at a distance from the bottom wall of the tank being greater than the first distance,   a controller configured to control the heating unit,   the method comprising:
 determining from a water temperature measurement signal provided by the at least one temperature sensor a water usage profile, the water usage profile providing for defined time intervals of a day and/or for defined days of a week a nominal temperature and a nominal volume of the heated water to be stored within the tank; and 
 operating the heating unit in such a manner that for each defined time interval of the day and/or for each defined day of the week an actual temperature and an actual volume of the heated water stored withing the tank corresponds automatically to a respective nominal value of the water usage profile. 
   
     
     
         2 . The method of  claim 1 , wherein;
 the hot water storage device has a first temperature sensor positioned at a second distance from the bottom wall of the tank and a second temperature sensor positioned at a third distance from the bottom wall of the tank, said the second distance being greater than the first distance and the third distance being greater than the second distance,   wherein the water usage profile is determined from a first water temperature measurement signal provided by the first temperature sensor and from a second water temperature measurement signal provided by the second temperature sensor and/or from an average water temperature signal of the first water temperature measurement signal and the second water temperature measurement signal.   
     
     
         3 . The method of  claim 1 , wherein the water usage profile is determined based on a change rate of the respective water temperature measurement signal in the respective time interval of the respective day. 
     
     
         4 . The method of  claim 1 , wherein the water usage profile is determined on basis of a frequency and of an amount of a hot water demand in the respective time intervals of the respective day. 
     
     
         5 . The method of  claim 1 , wherein the water usage profile is determined in such a manner that for each respective time interval of each respective day of the week, a nominal value pair comprising the nominal temperature and the nominal volume of the heated water to be stored within the tank is determined, wherein a nominal value pair of a set of nominal value pairs comprises:
 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,   wherein the second nominal temperature is greater than the first nominal temperature.   
     
     
         6 . The method of  claim 5 , wherein the set of nominal value pairs on basis of which the water usage profile for each respective time interval of each respective day of a week is determined further comprises:
 pair 5: third nominal volume and second nominal temperature, and/or   pair 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 of  claim 5 , comprising:
 determining, for each respective time interval of each respective day, a confidence factor associated with the nominal temperature and the nominal volume of the heated water to be stored within the tank,   wherein the confidence factor depends on a frequency and an amount of a hot water demand in the respective time intervals of the respective day.   
     
     
         8 . The method of  claim 7 , wherein;
 the confidence factor is increased when the frequency of hot water demands and/or the amount of a hot water demand is above a respective upper threshold within the respective time interval of the respective day,   the confidence factor is decreased when the frequency of hot water demands and/or the amount of a hot water demand is below a respective lower threshold within the respective time interval of the respective day,   the confidence factor remains unchanged when the frequency of hot water demands and/or the amount of a hot water demand is above a respective lower threshold and below the respective upper threshold.   
     
     
         9 . The method of  claim 7 , wherein;
 at an initial state or at an initialization state of the hot water storage device, the water usage profile of each time interval of each day of a week is initialized with a pair N (N=2 or 3 or 4) of the nominal value pairs,   when the confidence factor of the respective time interval of the respective day is below a lower limit, the water usage profile is changed to pair N−1 of the nominal value pairs,   when the confidence factor of the respective time interval of the respective day is above an upper limit, the water usage profile is changed to pair N+1 of the nominal value pairs,   when the confidence factor of the respective time interval of the respective day is above the lower limit and below the upper limit, the water usage profile remains at pair N of the nominal value pairs.   
     
     
         10 . The method of  claim 8 , wherein a change of the confidence factor of a respective time interval of a respective day affects the confidence factor of time intervals adjoining the respective time interval in which the confidence factor has changed. 
     
     
         11 . The method of  claim 1 , wherein the water temperature measurement signal provided by the at least one temperature sensor is provided to a database,
 wherein the database determines the water usage profile providing for each respective defined time interval of a respective day of a week the nominal temperature and the nominal volume of the heated water to be stored within the tank, and   wherein the controller operates the heating unit of basis of the water usage profile provided by the database to the controller.   
     
     
         12 . The method of  claim 1 , wherein the water temperature measurement signal provided by the at least one temperature sensor is provided to the controller,
 wherein the controller determines the water usage profile providing for each respective defined time interval of a respective day of a week the nominal temperature and the nominal volume of the heated water to be stored within the tank, and   wherein the controller operates the heating unit of basis of said water usage profile.   
     
     
         13 . A controller for a hot water storage device,
 the hot water storage device including:
 a tank configured to store water, 
 a heating unit positioned at a first distance from a bottom wall of the tank, and 
 at least one temperature sensor positioned at a distance from the bottom wall of the tank, said distance being greater than said first distance, 
   wherein the controller:
 is configured to control the heating unit and thereby the water temperature of the water stored within the tank, 
 is configured to determine from a water temperature measurement signal provided by the at least one temperature sensor a water usage profile, said water usage profile providing for defined time intervals of a day and/or for defined days of a week a nominal temperature and a nominal volume of the heated water to be stored within the tank, and 
 is configured to operate the heating unit in such a manner that for each defined time interval of a day and/or for each defined day of a week an actual temperature and an actual volume of the heated water stored withing the tank corresponds automatically to a respective nominal value of the water usage profile. 
   
     
     
         14 . The controller of  claim 13 , wherein the controller is configured to automatically determine the water usage profile based on a change rate of the respective water temperature measurement signal in the respective time interval of the respective day. 
     
     
         15 . A hot water storage device, comprising:
 a tank configured to store water, the tank having a bottom wall, a top wall and a side wall extending between the bottom wall and the top wall,   a heating unit positioned at a first distance from the bottom wall, the heating unit being configured to heat the water stored within the tank in such a manner that water heated by the heating unit rises up within the tank such that the heated water is stratified above unheated water within the tank,   at least one temperature sensor positioned at a distance from the bottom wall, the at least one temperature sensor being configured to measure a water temperature of the heated water, and   a controller,
 wherein the controller:
 is configured to control the heating unit and thereby the water temperature of the water stored within the tank, 
 
 is configured to determine from a water temperature measurement signal provided by the at least one temperature sensor a water usage profile, said water usage profile providing for defined time intervals of a day and/or for defined days of a week a nominal temperature and a nominal volume of the heated water to be stored within the tank, and
 is configured to operate the heating unit in such a manner that for each defined time interval of a day and/or for each defined day of a week an actual temperature and an actual volume of the heated water stored withing the tank corresponds automatically to a respective nominal value of the water usage profile. 
 
   
     
     
         16 . The method of  claim 2 , wherein the water usage profile is determined based on a change rate of the respective water temperature measurement signal in the respective time interval of the respective day. 
     
     
         17 . The method of  claim 2 , wherein the water usage profile is determined on basis of a frequency and of an amount of a hot water demand in the respective time intervals of the respective day. 
     
     
         18 . The method of  claim 11 , wherein the database is a cloud database. 
     
     
         19 . The method of  claim 11 , wherein the water temperature measurement signal provided by the at least one temperature sensor is provided to the controller,
 wherein the controller determines the water usage profile providing for each respective defined time interval of a respective day of a week the nominal temperature and the nominal volume of the heated water to be stored within the tank, and   wherein the controller operates the heating unit of basis of said water usage profile.   
     
     
         20 . The hot water storage device of  claim 15 , wherein the hot water storage device has a first temperature sensor positioned at a second distance from the bottom wall of the tank and a second temperature sensor positioned at a third distance from the bottom wall of the tank, the second distance being greater than the first distance and the third distance being greater than the second distance.