Central plant system with automated system curves calibration for pumps

Abstract

A controller for one or more pumps in a central plant is configured to obtain first values of flow rate of a fluid provided by the one or more pumps to a building or campus and corresponding first values of a pressure differential across the building or campus during a first time period, generate a system curve for the building or campus that defines a relationship between the flow rate and the pressure differential using the first values of flow rate and pressure differential during the first time period, predict a second value of the pressure differential across the building or campus during a second time period using the system curve and a second value of the flow rate during the second time period, and operate the one or more pumps to achieve the second value of the pressure differential across the building or campus during the second time period.

What is claimed is: 
     
         1 . A controller for central plant equipment 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 the one or more processors to perform operations comprising:
 obtaining first values of flow rate of a fluid provided by one or more pumps to a building or campus and corresponding first values of a pressure differential across the building or campus during a first time period;   generating a system curve for the building or campus that defines a relationship between the flow rate and the pressure differential using the first values of the flow rate and the pressure differential during the first time period;   predicting a second value of the pressure differential across the building or campus during a second time period using the system curve and a second value of the flow rate during the second time period; and   operating the one or more pumps to achieve the second value of the pressure differential across the building or campus during the second time period.   
     
     
         2 . The controller of  claim 1 , wherein generating the system curve comprises:
 determining whether the one or more pumps are arranged as primary pumps serving the central plant equipment or secondary pumps serving the building or campus; and   at least one of:
 using a first method for generating the system curve if the one or more pumps are arranged as the primary pumps; or 
 using a second method for generating the system curve if the one or more pumps are arranged as the secondary pumps. 
   
     
     
         3 . The controller of  claim 2 , wherein the first method for generating the system curve comprises subtracting a pressure drop caused by the central plant equipment from a pressure differential across the primary pumps to determine the first values of the pressure differential across the building or campus. 
     
     
         4 . The controller of  claim 2 , wherein the second method for generating the system curve comprises using a pressure differential across the secondary pumps as the first values of the pressure differential across the building or campus. 
     
     
         5 . The controller of  claim 1 , wherein:
 the system curve defines the pressure differential across the building or campus as a function of the flow rate of the fluid provided by the one or more pumps to the building or campus and one or more trainable model parameters; and   generating the system curve comprises determining values of the one or more trainable model parameters.   
     
     
         6 . The controller of  claim 5 , wherein:
 the system curve defines the pressure differential across the building or campus as a linear combination of a first term comprising a differential pressure offset and a second term comprising a scaling factor applied to the function of the flow rate;   the trainable model parameters comprise a first model parameter indicating the differential pressure offset and a second model parameter indicating the scaling factor.   
     
     
         7 . The controller of  claim 5 , wherein the trainable model parameters further comprise a third model parameter indicating a power applied to the flow rate in a second term of the system curve. 
     
     
         8 . The controller of  claim 1 , wherein operating the one or more pumps to achieve the second value of the pressure differential across the building or campus during the second time period comprises:
 determining whether the one or more pumps are arranged as primary pumps serving the central plant equipment or secondary pumps serving the building or campus; and   at least one of:
 using a first method for operating the one or more pumps if the one or more pumps are arranged as the primary pumps; or 
 using a second method for operating the one or more pumps if the one or more pumps are arranged as the secondary pumps. 
   
     
     
         9 . The controller of  claim 8 , wherein the first method for operating the one or more pumps comprises:
 adding a pressure drop caused by the central plant equipment to the pressure differential across the building or campus during the second time period to determine a pressure differential across the primary pumps; and   operating the one or more pumps to achieve the pressure differential across the primary pumps during the second time period.   
     
     
         10 . The controller of  claim 8 , wherein the second method for operating the one or more pumps comprises:
 using the pressure differential across the building or campus during the second time period as a pressure differential across the secondary pumps; and   operating the one or more pumps to achieve the pressure differential across the secondary pumps during the second time period.   
     
     
         11 . A method for operating one or more pumps in a central plant comprising:
 obtaining first values of flow rate of a fluid provided by the one or more pumps to a building or campus and corresponding first values of a pressure differential across the building or campus during a first time period;   generating a system curve for the building or campus that defines a relationship between the flow rate and the pressure differential using the first values of the flow rate and the pressure differential during the first time period;   predicting a second value of the pressure differential across the building or campus during a second time period using the system curve and a second value of the flow rate during the second time period; and   operating the one or more pumps to achieve the second value of the pressure differential across the building or campus during the second time period.   
     
     
         12 . The method of  claim 11 , wherein generating the system curve comprises:
 determining whether the one or more pumps are arranged as primary pumps serving central plant equipment or secondary pumps serving the building or campus; and   at least one of:
 using a first method for generating the system curve if the one or more pumps are arranged as the primary pumps; or 
 using a second method for generating the system curve if the one or more pumps are arranged as the secondary pumps. 
   
     
     
         13 . The method of  claim 12 , wherein the first method for generating the system curve comprises subtracting a pressure drop caused by the central plant equipment from a pressure differential across the primary pumps to determine the first values of the pressure differential across the building or campus. 
     
     
         14 . The method of  claim 12 , wherein the second method for generating the system curve comprises using a pressure differential across the secondary pumps as the first values of the pressure differential across the building or campus. 
     
     
         15 . The method of  claim 11 , wherein:
 the system curve defines the pressure differential across the building or campus as a function of the flow rate of the fluid provided by the one or more pumps to the building or campus and one or more trainable model parameters; and   generating the system curve comprises determining values of the one or more trainable model parameters.   
     
     
         16 . The method of  claim 15 , wherein:
 the system curve defines the pressure differential across the building or campus as a linear combination of a first term comprising a differential pressure offset and a second term comprising a scaling factor applied to the function of the flow rate;   the trainable model parameters comprise a first model parameter indicating the differential pressure offset and a second model parameter indicating the scaling factor.   
     
     
         17 . The method of  claim 16 , wherein the trainable model parameters further comprise a third model parameter indicating a power applied to the flow rate in the second term of the system curve. 
     
     
         18 . The method of  claim 11 , wherein operating the one or more pumps to achieve the second value of the pressure differential across the building or campus during the second time period comprises:
 determining whether the one or more pumps are arranged as primary pumps serving central plant equipment or secondary pumps serving the building or campus; and   at least one of:
 using a first method for operating the one or more pumps if the one or more pumps are arranged as the primary pumps; or 
 using a second method for operating the one or more pumps if the one or more pumps are arranged as the secondary pumps. 
   
     
     
         19 . The method of  claim 18 , wherein the first method for operating the one or more pumps comprises:
 adding a pressure drop caused by the central plant equipment to the pressure differential across the building or campus during the second time period to determine a pressure differential across the primary pumps; and   operating the one or more pumps to achieve the pressure differential across the primary pumps during the second time period.   
     
     
         20 . The method of  claim 18 , wherein the second method for operating the one or more pumps comprises:
 using the pressure differential across the building or campus during the second time period as a pressure differential across the secondary pumps; and   operating the one or more pumps to achieve the pressure differential across the secondary pumps during the second time period.