Method for controlling the pressure of the heat transfer fluid in a heating system

Abstract

A method for controlling the pressure of heat transfer fluid in a heating system including a thermo-sanitary appliance, in particular a gas boiler, the method including the following steps. Extrapolating minimum values of the fluid pressure from the original minimum values, within a time observation window corresponding to a given number of previous days. Identifying one or more ramps of the minimum values of the pressure of the fluid, within the time observation window. Calculating a plurality of characteristics relating to the trend of the pressure of the fluid on the basis of said one or more ramps of the minimum values. Providing the calculated characteristics to a machine learning classification model, adapted to produce a three-class classification, each of which is representative of the more or less high probability that in a future time window the thermo-sanitary appliance will block due to an excessively low value of fluid pressure.

1 . A Method for controlling the pressure of the heat transfer fluid circulating in a heating system, said system comprising at least:
 a thermo-sanitary appliance, in particular a gas boiler;   a primary circuit having a primary exchanger for the heating of the water intended to supply the heating bodies for the space heating;   a secondary circuit having a secondary exchanger for the heating of the domestic water intended for the users;   a pressure sensor adapted to measure the value of the pressure of said heat transfer fluid;   a control unit adapted to receive said pressure value of the fluid;   such method comprising at least the following steps in sequence:
 Step  1 : extrapolating the minimum values (P.MIN) of the pressure of the fluid from the original minimum values (P.RAW), within a time observation window (T.analysis) corresponding to a given number of previous days; 
 Step  2 : identifying one or more ramps of the minimum values (P.MIN) of the pressure of the fluid, within said time observation window (T.analysis); 
   characterized in that such method further comprises in sequence the following steps:
 Step  3 : calculating a plurality of characteristics relating to the trend of the pressure of the fluid on the basis of said one or more ramps of the minimum values (P.MIN) identified in Step  2 ; 
 Step  4 : providing said characteristics calculated in Step  3  to a machine learning classification model, previously trained with the history data of a multitude of heating systems, said model producing a three class classification in outlet, each of which is representative of the more or less high probability that in a future time window (T.prox) said thermo-sanitary appliance ( 1 ) will block due to an excessively low value of the pressure of said fluid, said three classes comprising:
 green class: representative of a high probability that said thermo-sanitary appliance will not incur, in said future time window (T.prox), into any blockage problem caused by an excessive drop in the pressure value of the fluid; 
 yellow class: representative of the fact that said thermo-sanitary appliance ( 1 ) will present, in said future time window (T.prox), a pressure value of the fluid lower than the recommended value, but not an obstacle to the continued operation of said appliance; 
 red class: representative of a high probability that said thermo-sanitary appliance ( 1 ) will incur, in said future time window (T.prox), into any blockage problem caused by an excessive drop in the pressure value of the fluid. 
 
   
     
     
         2 . Control method according to  claim 1 , wherein:
 following said classification into the yellow or red classes, the further step of the output of a notification to the technical assistance centre and/or the user is provided, said notification comprising:
 a warning with the suggestion of proceeding with a top up of the fluid in the circuit of the system in case of a yellow class classification; 
 a warning with the need of proceeding with a top up of the fluid in the circuit of the system in case of a red class classification. 
   
     
     
         3 . Method according to  claim 1 , wherein in said Step  1  of extrapolation of the minimum values (P.MIN) of the pressure of the fluid from the original minimum values (P.RAW), the latter are purified from limit and/or abnormal conditions, such as for example at least one among:
 the measurement of a pressure value by the pressure sensor, which detects an incorrect value equal to 0 bars; 
 the maintenance of the system by a technician, who again empties and refills the circuit with fluid, 
 the increase in the pressure value due to the heat demand, a condition in which there is typically an increase in the pressure of approximately 0.5 bars; 
 the topping up operation from the fluid inside the hydraulic circuit, by a technician or directly by the user. 
 
     
     
         4 . Method according to  claim 1 , wherein in said identification Step  2  of the one or more ramps of the minimum values (P.MIN) of the pressure of the fluid, said ramps are identified between two events or conditions such as at least one among:
 increase in the minimum pressure value (P.MIN) caused by a top up of the fluid in the hydraulic circuit, such as to raise this value by a preset threshold (for example 0.4 bars); 
 block error of the thermo-sanitary appliance, in case that the pressure sensor detects a pressure value lower than a preset threshold (for example 0.3 bars); 
 absence of the pressure signal for a preset duration (for example at least 6 h), caused by the switching off of the thermo-sanitary appliance. 
 
     
     
         5 . Method according to  claim 1 , wherein in said calculation Step  3  of a plurality of characteristics, said ramps of the minimum values (P.MIN) of the pressure of the fluid identified in the Step  2  are processed according to the following routines:
 description of the behaviour of the pressure of the last ramp; 
 analysis of the validity of the data processed in said Step  2 ; 
 counting of the ramps identified in said Step  2 ; 
 description of the signal of the pressures outlined by the ramps, within a time interval equal to a submultiple of the observation time window (T.analysis), each of said submultiples having equal duration; 
 analysis of the overall trend of the signal within the entire observation time window (T.analysis). 
 
     
     
         6 . Method according to  claim 5 , wherein through said description routine of the behavior of the pressure of the last ramp, said method calculates a plurality of characteristics, among which one or more of the following:
 the descent speed of the minimum pressure value (P.MIN) of the last ramp identified;   the minimum pressure value (P.MIN) of said last ramp;   a binary value (0 or 1) if, in the last week, for at least the 50% of the time, the pressure value (P.MIN) remained stable at values lower than the standard suggested by the installer: in such case the binary value is equal to 1.   
     
     
         7 . Method according to  claim 5 , wherein through said analysis routine of the validity of the data processed in said Step  2 , said method calculates a plurality of characteristics, among which one or more of the following:
 percentage of the minimum pressure values (P.MIN) within the observation time window (T.analysis);   percentage of such values below a certain threshold;   number of ramps identified in the observation time window (T.analysis);   percentage of the valid pressure values (P.MIN) of the last ramp identified in the observation time window (T.analysis).   
     
     
         8 . Method according to  claim 5 , wherein through said description routine of the pressures outlined by the ramps, within a time window equal to a submultiple of the observation time window (T.analysis), said method calculates a plurality of characteristics, among which one or more of the following:
 the descent speed of the pressure value (P.MIN);   the pressure value (P.MIN) at the beginning of the interval;   a binary value (0 or 1) if the last ramp identified in the specific interval coincides with the last ramp of the entire observation time window (T.analysis): in such case the binary value is equal to 1;   the value of the variance of the pressure signal (P.MIN);   the average of the pressure signal (P.MIN);   the difference between the maximum value and the minimum value of the pressure signal (P.MIN);   the minimum value of the pressure signal (P.MIN);   the maximum value of the pressure signal (P.MAX).   
     
     
         9 . Method according to  claim 5 , wherein through said analysis routine of the overall trend of the signal within the observation time window (T.analysis), said method calculates a plurality of characteristics, among which one or more of the following:
 the linear regression of the descent speeds of the pressure value (P.MIN) of the N intervals of equal duration into which the observation window (T.analysis) has been divided;   the Pearson correlation coefficient of such linear regression.   
     
     
         10 . Method according to  claim 1 , wherein said observation time window (T.analysis) is equal to 20 days. 
     
     
         11 . Method according to the  claim 10 , wherein said submultiple of the observation time window (T.analysis) lasts 2 days. 
     
     
         12 . Method according to  claim 1 , wherein said future time window (T.prox) lasts 10 days. 
     
     
         13 . A heating system comprising at least:
 a thermo-sanitary appliance, in particular a gas boiler or an indoor heating heat pump or a hybrid boiler;   a primary circuit having a primary exchanger for the heating of water intended to supply heating bodies for space heating;   a secondary circuit having a secondary exchanger for the heating of domestic water intended for users;   a pressure sensor adapted to measure the value of the pressure of said heat transfer fluid;   a control unit adapted to receive said pressure value of the fluid, wherein said control unit is adapted to exchange information with said pressure sensor and to carry out the steps of the method according to  claim 1 .