Compensating for Sensor Thermal Lag

Abstract

Exemplary embodiments are disclosed of a method of compensating for thermal lag in a temperature control system. In an exemplary embodiment, a method is performed by a controller of the temperature control system. The method includes receiving a first temperature obtained by a temperature sensing device at an end of a temperature control cycle. A second temperature obtained by the temperature sensing device is received at a pre-defined time after the end of the temperature control cycle. The method includes changing an operational set-point temperature of the temperature control system using a difference between the received temperatures.

What is claimed is: 
     
         1 . A method of compensating for thermal lag in a temperature control system, the method comprising:
 receiving a first temperature obtained by a temperature sensing device at an end of a temperature control cycle, the temperature sensing device including a thermistor and probe assembly secured in a water heater tank wall by a threaded region such that the thermistor is immersed in water stored in the tank;   receiving a second temperature obtained by the temperature sensing device at an expiration of a pre-defined time after the end of the temperature control cycle; and   changing an operational set-point temperature of the temperature control system by subtracting a difference between the received temperatures from a control set-point temperature of the temperature control system;   the method performed by a controller of the temperature control system.   
     
     
         2 . The method of  claim 1 , performed to offset a control set-point temperature of the temperature control system. 
     
     
         3 . The method of  claim 1 , further comprising:
 receiving a third temperature obtained by the temperature sensing device at an end of a second temperature control cycle;   receiving a fourth temperature obtained by the temperature sensing device at the pre-defined time after the end of the second temperature control cycle;   averaging the difference between the first and second temperatures with a difference between the third and fourth temperatures to obtain an average difference; and   using the average difference to offset a control set-point temperature of the temperature control system.   
     
     
         4 . The method of  claim 1 , performable by the controller as to two temperature sensing devices having different thermal transfer rates. 
     
     
         5 . The method of  claim 1 , wherein the end of the temperature control cycle is reached when a selected control set-point is reached in the temperature control system. 
     
     
         6 . The method of  claim 1 , performed without altering a selected control set-point of the temperature control system. 
     
     
         7 . The method of  claim 1 , wherein the pre-defined time is three minutes. 
     
     
         8 . The method of  claim 1 , wherein the temperature control cycle includes a heating cycle or a cooling cycle. 
     
     
         9 . The method of  claim 1 , wherein a length of the pre-defined time is based on insulation values of the temperature sensing device materials.