Method, computer readable medium and household appliance for performing limescale deposition detection by thermal pulse technology

Abstract

A method controls a household appliance being or containing a water heater with regard to limescale deposition. The method includes generating at least one thermal pulse by operation of an electrical heating element of the water heater, and measuring a plurality of successive temperature values. The method further includes determining one or more parameter values of a measurement pattern arising from the plurality of successive temperature values and their respective time of measurement, and ascertaining a limescale deposition state of the water heater based on the determined parameter value. A household appliance contains a computer readable medium having stored thereon instructions configured to trigger, when executed, the household appliance to perform such a method.

1 . A method of controlling a household appliance being or containing a water heater with regard to limescale deposition, the method comprises the steps of:
 generating at least one thermal pulse by operation of an electrical heating element of the water heater during a pulse time interval;   measuring, during a measurement time interval containing the pulse time interval and by at least one temperature sensor, a plurality of successive temperature values;   determining at least one parameter value of a measurement pattern arising from the plurality of successive temperature values and their respective time of measurement; and   ascertaining a limescale deposition state of the water heater based on the at least one parameter value.   
     
     
         2 . The method according to  claim 1 , wherein the limescale deposition state includes:
 a limescale accumulation percentage indicator reflecting a current value of a limescale accumulation percentage of the water heater with respect to a predefined maximum accumulation; and/or   a decalcifying need indicator reflecting a stage contained in a predetermined graduation of needs for decalcifying the water heater.   
     
     
         3 . The method according to  claim 1 , which further comprises providing a signal to a user based on the limescale deposition state. 
     
     
         4 . The method according to  claim 1 , wherein the at least one parameter value contains:
 a maximum temperature occurring in the measurement pattern;   a maximum temperature difference occurring, in the measurement pattern, between a measured temperature value and its antecedent measured temperature value;   a minimum temperature difference occurring, in the measurement pattern, between a measured temperature value and its antecedent measured temperature value;   a maximum value of a derivative of a function interpolating the measurement pattern;   a minimum value of the derivative of the function interpolating the measurement pattern; and/or   a value of a mathematical function applied to at least one of the maximum temperature, the maximum temperature difference, the minimum temperature difference, the maximum value and/or the minimum value.   
     
     
         5 . The method according to  claim 1 , wherein the at least one parameter value includes a moving average of the plurality of successive temperature values over time, and/or a moving average of differences of the successive temperature values over time. 
     
     
         6 . The method according to  claim 1 , wherein the ascertaining of the limescale deposition state is further based on at least one previous parameter value determined with regard to at least one former thermal pulse previously generated by means of the electrical heating element. 
     
     
         7 . The method according to  claim 1 , wherein the thermal pulse has a duration of:
 at most 5 seconds; and/or   at least 0.5 seconds.   
     
     
         8 . The method according to  claim 1 , wherein the thermal pulse has a duration of:
 at most 4 seconds; and/or   at least 1 second.   
     
     
         9 . The method according to  claim 1 , wherein the thermal pulse has a duration of:
 at most 3 seconds; and/or   at least 2 seconds.   
     
     
         10 . The method according to  claim 1 , wherein during the measurement time interval, at least 10 and/or at most 100 of the successive temperature values are measured per second. 
     
     
         11 . A non-transitory computer readable medium storing computer executable instructions configured to trigger, when executed, a household appliance being or comprising a water heater with an electrical heating element, at least one temperature sensor and a computer to perform a method of controlling the household appliance, the method comprises the steps of:
 generating at least one thermal pulse by operation of the electrical heating element of the water heater during a pulse time interval;   measuring, during a measurement time interval containing the pulse time interval and by said at least one temperature sensor, a plurality of successive temperature values;   determining at least one parameter value of a measurement pattern arising from the plurality of successive temperature values and their respective time of measurement; and   ascertaining a limescale deposition state of the water heater based on the at least one parameter value.   
     
     
         12 . A household appliance being or comprising a water heater, the household appliance comprising:
 an electrical heating element;   at least one temperature sensor;   a computer, wherein the household appliance is configured to perform a method of controlling the household appliance, the method comprises the steps of:
 generating at least one thermal pulse by operation of said electrical heating element of the water heater during a pulse time interval; 
 measuring, during a measurement time interval containing the pulse time interval and by said at least one temperature sensor, a plurality of successive temperature values; 
 determining at least one parameter value of a measurement pattern arising from the plurality of successive temperature values and their respective time of measurement; and 
 ascertaining a limescale deposition state of the water heater based on the at least one parameter value.