Chiller system with efficiency estimation

Abstract

A system includes processing circuitry programmed to perform operations. The operations include determining whether a first sensor is available at a chiller. The first sensor includes a temperature sensor or a pressure sensor of the chiller. The operations include, responsive to determining that the first sensor is unavailable, determining an estimated value for the first sensor based on measurements from available sensors of the chiller (where the available sensors include at least one of an available temperature sensor or an available pressure sensor of the chiller), determining a plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors, and determining an efficiency of the chiller based on the plurality of enthalpy points. The operations also include affecting an operation of the chiller based on the efficiency.

What is claimed is: 
     
         1 . A system comprising:
 one or more processors; and   one or more non-transitory computer-readable media storing instructions that, when executed by the one or more processors, cause at least one of the processors to perform operations comprising:
 determining whether a first sensor is available at a chiller, the first sensor comprising a temperature sensor or a pressure sensor of the chiller; 
 responsive to determining that the first sensor is available, determining a plurality of enthalpy points by executing first logic that uses a measurement from the first sensor; 
 responsive to determining that the first sensor is unavailable:
 automatically switching from the first logic to second logic to compensate for unavailability to the first sensor; and 
 determining the plurality of enthalpy points using the second logic; and 
 
 determining an efficiency of the chiller based on the plurality of enthalpy points; 
 affecting an operation of the chiller based on the efficiency. 
   
     
     
         2 . The system of  claim 1 , wherein determining whether the first sensor is available at the chiller comprises determining whether a measurement was obtained from the first sensor. 
     
     
         3 . The system of  claim 1 , wherein determining whether the first sensor is available at the chiller comprises determining whether a measurement obtained from the first sensor is within a preset threshold. 
     
     
         4 . The system of  claim 1 , the operations comprising, responsive to determining that the first sensor is unavailable, determining an estimated value for the measurement from the first sensor based on measurements from available sensors of the chiller based on a modeled relationship between the available sensors and the first sensor. 
     
     
         5 . The system of  claim 1 , wherein determining the plurality of enthalpy points uses a modeled relationship between temperature, pressure, and an enthalpy point. 
     
     
         6 . The system of  claim 1 , wherein determining the efficiency of the chiller based on the plurality of enthalpy points comprises calculating a coefficient of performance. 
     
     
         7 . The system of  claim 1 , wherein the first sensor is a preinstalled sensor located along a refrigeration circuit of the chiller. 
     
     
         8 . The system of  claim 1 , wherein the first logic uses different input variables than the second logic. 
     
     
         9 . The system of  claim 1 , wherein the operations further comprise obtaining an operation code from the chiller, wherein the operation code indicates whether the chiller is operating, and determining the efficiency is performed responsive to determining that the chiller is in steady state operations based on the operating code. 
     
     
         10 . A method comprising:
 determining whether a first sensor is available at a refrigeration circuit;   responsive to determining that the first sensor is unavailable:
 determining an estimated value for the first sensor based on measurements from available sensors of the refrigeration circuit, the available sensors comprising at least one of a temperature sensor or a pressure sensor; and 
 determining a plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors; and 
 determining an efficiency of the refrigeration circuit based on the plurality of enthalpy points; and 
   affecting an operation of the refrigeration circuit based on the efficiency.   
     
     
         11 . The method of  claim 10 , wherein determining whether the first sensor is available at the refrigeration circuit comprises determining whether a measurement was obtained from the first sensor. 
     
     
         12 . The method of  claim 10 , wherein determining whether the first sensor is available at the refrigeration circuit comprises determining whether a measurement obtained from the first sensor is within an expected range. 
     
     
         13 . The method of  claim 10 , wherein determining the estimated value for the first sensor based on the measurements from the available sensors comprises calculating the estimated value for the first sensor based on a modeled relationship between the available sensors and the first sensor. 
     
     
         14 . The method of  claim 10 , wherein determining the plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors comprises calculating the plurality of enthalpy points using a modeled relationship between temperature, pressure, and the plurality of enthalpy points. 
     
     
         15 . The method of  claim 10 , wherein determining the efficiency of the refrigeration circuit based on the plurality of enthalpy points comprises calculating a coefficient of performance. 
     
     
         16 . The method of  claim 10 , wherein the first sensor measures pressure or temperature at a point along the refrigeration circuit. 
     
     
         17 . The method of  claim 10 , comprising converting the measurement from the first sensor and the measurements from the available sensors into standard units. 
     
     
         18 . The method of  claim 10 , further comprising obtaining an operation code from the refrigeration circuit, wherein the operation code indicates that the refrigeration circuitry is operating, and wherein the determining steps are performed responsive to determining that the refrigeration circuit is on and in a steady state based on the operation code. 
     
     
         19 . The method of  claim 18 , wherein affecting the operation of the refrigeration circuit comprises changing a setting and causing the refrigeration circuit to operate in accordance with the setting. 
     
     
         20 . A method comprising:
 determining available sensors and unavailable sensor types for a unit of building equipment;   automatically selecting logic from a set of available logic based on the available sensors and the unavailable sensor types for the unit of building equipment;   determining an efficiency of the unit of building equipment using the logic and measurements from the available sensors; and   affecting an operation of the unit of building equipment based on the efficiency.