Capacity sensing for an air conditioning appliance over time

Abstract

A method of capacity sensing in an AC unit is provided. The method includes determining an airflow rate through the AC unit. The method also includes determining a temperature difference between a pair of discrete points along an airflow path of the AC unit. The method further includes determining a measured capacity value based on the temperature difference. The method also includes determining a variation value between the measured capacity value and a predetermined capacity value. The method further includes determining a fault status based on the variation value. The method still further includes initiating a status indicator from the AC unit based on the fault status.

What is claimed is: 
     
         1 . A method of capacity sensing in an AC unit, the method comprising:
 determining an airflow rate through the AC unit;   determining a temperature difference between a pair of discrete points along an airflow path of the AC unit;   determining a measured capacity value based on the temperature difference;   determining a variation value between the measured capacity value and a predetermined capacity value;   determining a fault status based on the variation value; and   initiating a status indicator from the AC unit based on the fault status.   
     
     
         2 . The method of  claim 1 , wherein the temperature difference comprises the difference between an inlet air temperature and an outlet air temperature. 
     
     
         3 . The method of  claim 1 , wherein the airflow rate comprises a mass flow rate determined by multiplying a volumetric flow rate of the AC unit by an air density value. 
     
     
         4 . The method of  claim 3 , further comprising:
 determining the air density value prior to determining the measured capacity value, wherein the air density value is determined from a point temperature at a discrete first point of the pair of discrete points.   
     
     
         5 . The method of  claim 3 , further comprising:
 determining the volumetric flow rate prior to determining the measured capacity value, wherein determining the volumetric flow rate comprises measuring a fan speed of a fan located in the AC unit.   
     
     
         6 . The method of  claim 1 , wherein the fault status comprises two possible values, the two possible values comprising:
 a first value that depicts that a fault has been detected; and   a second value that depicts that a fault is absent.   
     
     
         7 . The method of  claim 1 , wherein the predetermined capacity value is embedded in the AC unit. 
     
     
         8 . The method of  claim 1 , wherein the predetermined capacity value is based on an outdoor compressor speed and an outdoor ambient temperature. 
     
     
         9 . The method of  claim 1 , further comprising:
 sending a message containing the status indicator.   
     
     
         10 . An air conditioner (AC) unit, comprising:
 a housing unit;   a sealed refrigerative system housed in the housing unit;   an interior fan for providing airflow through the AC unit, the interior fan housed within the housing unit and in connection with the sealed refrigerative system to supply airflow across the sealed refrigerative system;   a first thermistor positioned at a first discrete point of a pair of discrete points;   a second thermistor positioned at a second discrete point of the pair of discrete points;   a controller configured to direct a conditioning operation, the conditioning operation comprising:
 determining an airflow rate through the AC unit; 
 determining a temperature difference between the pair of discrete points along an airflow path of the AC unit; 
 determining a measured capacity value based on the temperature difference; 
 determining a variation value between the measured capacity value and a predetermined capacity value; 
 determining a fault status based on the variation value; and 
 initiating a status indicator from the AC unit based on the fault status. 
   
     
     
         11 . The AC unit of  claim 10 , wherein the temperature difference comprises the difference between an inlet air temperature and an outlet air temperature. 
     
     
         12 . The AC unit of  claim 10 , wherein the airflow rate comprises a mass flow rate determined by multiplying a volumetric flow rate of the AC unit by an air density value. 
     
     
         13 . The AC unit of  claim 12 , further comprising:
 determining the air density value prior to determining the measured capacity value, wherein the air density value is determined from a point temperature at the first discrete point of the pair of discrete points.   
     
     
         14 . The AC unit of  claim 12 , further comprising:
 determining the volumetric flow rate prior to determining the measured capacity value, wherein determining the volumetric flow rate comprises measuring a fan speed of a fan located in the AC unit.   
     
     
         15 . The AC unit of  claim 10 , wherein the fault status comprises two possible values, the two possible values comprising:
 a first value that depicts that a fault has been detected; and   a second value that depicts that a fault is absent.   
     
     
         16 . The AC unit of  claim 10 , wherein the predetermined capacity value is embedded in the AC unit. 
     
     
         17 . The AC unit of  claim 10 , wherein the predetermined capacity value is based on an outdoor compressor speed and an outdoor ambient temperature. 
     
     
         18 . The AC unit of  claim 10 , further comprising:
 sending a message containing the status indicator.