Control systems and methods for HVAC equipment with fluid loop thermal energy storage

Abstract

Disclosed herein are related to a system, a method, and a non-transitory computer readable medium for operating an energy plant. In one aspect, the system generates a regression model of a produced thermal energy load produced by a supply device of the plurality of devices. The system predicts the produced thermal energy load produced by the supply device for a first time period based on the regression model. The system determines a heat capacity of gas or liquid in the loop based on the predicted produced thermal energy load. The system generates a model of mass storage based on the heat capacity. The system predicts an induced thermal energy load during a second time period at a consuming device of the plurality of devices based on the model of the mass storage. The system operates the energy plant according to the predicted induced thermal energy load.

What is claimed is: 
     
       1. A controller for an energy plant including a fluid loop formed by a plurality of devices, the controller comprising:
 a processing circuit comprising a processor and memory storing instructions executed by the processor, the processing circuit configured to:
 obtain a maximum allowable temperature and a minimum allowable temperature of gas or liquid in the fluid loop; 
 generate a model indicating a relationship between (i) a temperature of the gas or the liquid in the fluid loop, and (ii) a difference between a first thermal energy load removed from the fluid loop by a load device of the plurality of devices and a second thermal energy load supplied to the fluid loop by a supply device of the plurality of devices; 
 generate a cost function with a constraint according to the model; 
 determine control decision values based on the cost function; and 
 operate the energy plant according to the control decision values to control the temperature of the gas or liquid in the fluid loop by adjusting the second thermal energy load supplied to the fluid loop by the supply device. 
 
 
     
     
       2. The controller of  claim 1 , wherein the constraint is to keep the temperature of the gas or the liquid in the fluid loop to be between the maximum allowable temperature and the minimum allowable temperature, when the energy plant operates according to the control decision values. 
     
     
       3. The controller of  claim 1 , wherein the control decision values include when to defer the second thermal energy load supplied to the fluid loop by the supply device and an amount of the second thermal energy load. 
     
     
       4. The controller of  claim 1 , wherein the cost function corresponds to a total energy consumed by the energy plant. 
     
     
       5. The controller of  claim 1 , wherein the control decision values are determined to minimize the cost function, while complying with the constraint. 
     
     
       6. The controller of  claim 1 , wherein the processing circuit is configured to:
 generate a regression model of the second thermal energy load; 
 predict the second thermal energy load supplied to the fluid loop by the supply device for a first time period based on the regression model; 
 determine a heat capacity of the gas or the liquid in the fluid loop based on the predicted second thermal energy load; and 
 generate the model based on the heat capacity. 
 
     
     
       7. The controller of  claim 6 , wherein the processing circuit is configured to:
 obtain load data indicating the second thermal energy load during a second time period, the second time period before the first time period, 
 wherein the processing circuit is configured to generate the regression model based on the load data. 
 
     
     
       8. The controller of  claim 7 , wherein the processing circuit is configured to:
 filter the second thermal energy load during the second time period, 
 wherein the processing circuit is configured to generate the regression model based on the filtered thermal energy load. 
 
     
     
       9. A method for an energy plant including a fluid loop formed by a plurality of devices, the method including:
 obtaining a maximum allowable temperature and a minimum allowable temperature of gas or liquid in the fluid loop; 
 generating a model indicating a relationship between (i) a temperature of the gas or the liquid in the fluid loop, and (ii) a difference between a first thermal energy load removed from the fluid loop by a load device of the plurality of devices and a second thermal energy load supplied to the fluid loop by a supply device of the plurality of devices; 
 generating a cost function with a constraint according to the model; 
 determining control decision values based on the cost function; and 
 operating the energy plant according to the control decision values to control the temperature of the gas or liquid in the fluid loop by adjusting the second thermal energy load supplied to the fluid loop by the supply device. 
 
     
     
       10. The method of  claim 9 , wherein the constraint is to keep the temperature of the gas or the liquid in the fluid loop to be between the maximum allowable temperature and the minimum allowable temperature, when the energy plant operates according to the control decision values. 
     
     
       11. The method of  claim 9 , wherein the control decision values include when to defer the second thermal energy load supplied to the fluid loop by the supply device and an amount of the second thermal energy load. 
     
     
       12. The method of  claim 9 , wherein the cost function corresponds to a total energy consumed by the energy plant. 
     
     
       13. The method of  claim 9 , wherein the control decision values are determined to minimize the cost function, while complying with the constraint. 
     
     
       14. The method of  claim 9 , further comprising:
 generating a regression model of the second thermal energy load; 
 predicting the second thermal energy load supplied to the fluid loop by the supply device for a first time period based on the regression model; 
 determining a heat capacity of the gas or the liquid in the fluid loop based on the predicted second thermal energy load; and 
 generate the model based on the heat capacity. 
 
     
     
       15. The method of  claim 14 , further comprising:
 obtaining load data indicating the second thermal energy load during a second time period by the supply device, the second time period before the first time period, 
 wherein the regression model is generated based on the load data. 
 
     
     
       16. The method of  claim 15 , further comprising:
 filtering the second thermal energy load during the second time period, 
 wherein the regression model is generated based on the filtered thermal energy load. 
 
     
     
       17. A non-transitory computer readable medium storing instructions for an energy plant including a fluid loop formed by a plurality of devices, the instructions when executed by a processor cause the processor to:
 obtain a maximum allowable temperature and a minimum allowable temperature of gas or liquid in the fluid loop; 
 generate a model indicating a relationship between (i) a temperature of the gas or the liquid in the fluid loop, and (ii) a difference between a first thermal energy load removed from the fluid loop by a load device of the plurality of devices and a second thermal energy load supplied to the fluid loop by a supply device of the plurality of devices; 
 generate a cost function with a constraint according to the model; 
 determine control decision values based on the cost function; and 
 operate the energy plant according to the control decision values to control the temperature of the gas or liquid in the fluid loop by adjusting the second thermal energy load supplied to the fluid loop by the supply device. 
 
     
     
       18. The non-transitory computer readable medium of  claim 17 , wherein the constraint is to keep the temperature of the gas or the liquid in the fluid loop to be between the maximum allowable temperature and the minimum allowable temperature, when the energy plant operates according to the control decision values. 
     
     
       19. The non-transitory computer readable medium of  claim 17 , wherein the control decision values include when to defer the second thermal energy load supplied to the fluid loop by the supply device and an amount of the second thermal energy load. 
     
     
       20. The non-transitory computer readable medium of  claim 17 , wherein the cost function corresponds to a total energy consumed by the energy plant, and wherein the control decision values are determined to minimize the cost function, while complying with the constraint. 
     
     
       21. A controller for a fluid loop formed by a plurality of devices, the controller comprising:
 a processing circuit comprising a processor and memory storing instructions executed by the processor, the processing circuit configured to:
 obtain a maximum allowable temperature and a minimum allowable temperature of gas or liquid in the fluid loop; 
 generate a model indicating a relationship between (i) a temperature of gas or liquid in the fluid loop and (ii) a difference between a first thermal energy load removed from the fluid loop by a load device of the plurality of devices and a second thermal energy load supplied to the fluid loop by a supply device of the plurality of devices; 
 generate a cost function with a constraint according to the model; 
 determine control decision values based on the cost function; and 
 operate the supply device according to the control decision values to control the temperature of the gas or liquid in the fluid loop by adjusting the second thermal energy load supplied to the fluid loop by the supply device.  
   
     
     
       22. The controller of  claim 21 , wherein the control decision values comprise a deferred thermal energy load indicating an amount of thermal energy to discharge from the fluid loop in excess of the second thermal energy load supplied to the fluid loop by the supply device.  
     
     
       23. The controller of  claim 21 , wherein the control decision values comprise a deferred thermal energy load which causes the temperature of the gas or liquid in the fluid loop to increase toward the maximum allowable temperature or decrease toward the minimum allowable temperature when the deferred thermal energy load is discharged from the fluid loop.  
     
     
       24. The controller of  claim 21 , wherein the control decision values comprise when to defer the second thermal energy load supplied to the fluid loop by the supply device based on a thermal mass of the gas or liquid in the fluid loop.  
     
     
       25. The controller of  claim 21 , wherein the processing circuit is configured to predict an increase or decrease in the temperature of the gas or liquid in the fluid loop based on an amount of underproduction or overproduction of the second thermal energy load supplied to the fluid loop by the supply device.  
     
     
       26. The controller of  claim 21 , wherein the processing circuit is configured to determine a thermal mass of the gas or liquid in the fluid loop using the model.  
     
     
       27. The controller of  claim 26 , wherein the processing circuit is configured to determine an energy capacity of the gas or liquid in the fluid loop based on the thermal mass of the gas or liquid in the fluid loop.  
     
     
       28. A method for operating a fluid loop formed by a plurality of devices, the method comprising:
 obtaining a maximum allowable temperature and a minimum allowable temperature of gas or liquid in the fluid loop;   generating a model indicating a relationship between (i) a temperature of gas or liquid in the fluid loop and (ii) a difference between a first thermal energy load removed from the fluid loop by a load device of the plurality of devices and a second thermal energy load supplied to the fluid loop by a supply device of the plurality of devices;   generating a cost function with a constraint according to the model;   determining control decision values based on the cost function; and   operating the supply device according to the control decision values to control the temperature of the gas or liquid in the fluid loop by adjusting the second thermal energy load supplied to the fluid loop by the supply device.    
     
     
       29. The method of  claim 28 , wherein the control decision values comprise a deferred thermal energy load indicating an amount of thermal energy to discharge from the fluid loop in excess of the second thermal energy load supplied to the fluid loop by the supply device.  
     
     
       30. The method of  claim 28 , wherein the control decision values comprise a deferred thermal energy load which causes the temperature of the gas or liquid in the fluid loop to increase toward the maximum allowable temperature or decrease toward the minimum allowable temperature when the deferred thermal energy load is discharged from the fluid loop.  
     
     
       31. The method of  claim 28 , wherein the control decision values comprise when to defer the second thermal energy load supplied to the fluid loop by the supply device based on a thermal mass of the gas or liquid in the fluid loop.  
     
     
       32. The method of  claim 28 , comprising predicting an increase or decrease in the temperature of the gas or liquid in the fluid loop based on an amount of underproduction or overproduction of the second thermal energy load supplied to the fluid loop by the supply device.  
     
     
       33. The method of  claim 28 , comprising determining a thermal mass of the gas or liquid in the fluid loop using the model.  
     
     
       34. The method of  claim 33 , comprising determining an energy capacity of the gas or liquid in the fluid loop based on the thermal mass of the gas or liquid in the fluid loop.  
     
     
       35. One or more non-transitory computer readable media storing instructions for operating a fluid loop formed by a plurality of devices, wherein the instructions, when executed by one or more processors, cause the one or more processors to:
 obtain a maximum allowable temperature and a minimum allowable temperature of gas or liquid in the fluid loop;   generate a model indicating a relationship between (i) a temperature of gas or liquid in the fluid loop and (ii) a difference between a first thermal energy load removed from the fluid loop by a load device of the plurality of devices and a second thermal energy load supplied to the fluid loop by a supply device of the plurality of devices;   generate a cost function with a constraint according to the model;   determine control decision values based on the cost function; and   operate the supply device according to the control decision values to control the temperature of the gas or liquid in the fluid loop by adjusting the second thermal energy load supplied to the fluid loop by the supply device.    
     
     
       36. The non-transitory computer readable media of  claim 35 , wherein the control decision values comprise a deferred thermal energy load indicating an amount of thermal energy to discharge from the fluid loop in excess of the second thermal energy load supplied to the fluid loop by the supply device.  
     
     
       37. The non-transitory computer readable media of  claim 35 , wherein the control decision values comprise a deferred thermal energy load which causes the temperature of the gas or liquid in the fluid loop to increase toward the maximum allowable temperature or decrease toward the minimum allowable temperature when the deferred thermal energy load is discharged from the fluid loop.  
     
     
       38. The non-transitory computer readable media of  claim 35 , wherein the control decision values comprise when to defer the second thermal energy load supplied to the fluid loop by the supply device based on a thermal mass of the gas or liquid in the fluid loop.  
     
     
       39. The non-transitory computer readable media of  claim 35 , wherein the instructions cause the one or more processors to predict an increase or decrease in the temperature of the gas or liquid in the fluid loop based on an amount of underproduction or overproduction of the second thermal energy load supplied to the fluid loop by the supply device.  
     
     
       40. The non-transitory computer readable media of  claim 35 , wherein the instructions cause the one or more processors to determine at least one of a thermal mass of the gas or liquid in the fluid loop or an energy capacity of the gas or liquid in the fluid loop using the model.