Thermostat with energy modeling

Abstract

A thermostat for a building space is disclosed. The thermostat can include a processing circuit. The processing circuit can cause building equipment to heat or cool the building space via one or more heating outputs or one or more cooling outputs. The processing circuit can record the length of time that the processing circuit causes the building equipment to heat or cool the building space. The processing circuit can simulate a thermal plant model to determine a simulated runtime, wherein the thermal plant model is a thermal plant model of the building space and the building equipment. The processing circuit can determine a number of hours saved based on the simulated runtime and the recorded length of time

What is claimed is: 
     
         1 . A method for determining energy savings of a thermostat, the method comprising:
 causing, by one or more processing circuits of a thermostat, building equipment to heat or cool a building space via one or more heating outputs or one or more cooling outputs of the thermostat;   recording, by the one or more processing circuits of the thermostat, the length of time that the building equipment heating or cooling the building space;   simulating, by the one or more processing circuits of the thermostat, a thermal plant model to determine a simulated runtime, wherein the thermal plant model is a thermal plant model of the building space and the building equipment; and   determining, by the one or more processing circuits of the thermostat, a number of hours saved based on the simulated runtime and the recorded length of time.   
     
     
         2 . The method of  claim 1 , further comprising identifying, by the one or more processing circuits, the thermal plant model from environmental data and control outputs of the thermostat via a stochastic parameter estimation method. 
     
     
         3 . The method of  claim 2 , wherein the stochastic parameter estimation method is at least one or a combination of linear least squares, non-linear least squares, a variants least square method, a robust linear least squares method, and a robust non-linear least squares method. 
     
     
         4 . The method of  claim 2 , wherein generating, by the one or more processing circuits, the thermal plant model comprises:
 generating an initial set of model parameters for the thermal plant model with least squares; and   generating a set of model parameters for the thermal plant model based on at least the initial set of model parameters for the thermal plant model and non-linear least squares.   
     
     
         5 . The method of  claim 4 , wherein generating the set of model parameters for the thermal plant model comprises iteratively solving for the set of model parameters with non-linear least squares for a predetermined number of iterations or based upon parameter convergence. 
     
     
         6 . The method of  claim 4 , wherein generating the initial set of model parameters for the thermal plant model comprises:
 generating, with least squares, the initial set of model parameters to be a first set of initial model parameters if the building equipment is configured to heat the building space; and   generating, with least squares, the initial set of model parameters to be a second set of initial model parameters if the building equipment is configured to cool the building space.   
     
     
         7 . The method of  claim 6 , wherein generating, with least squares, the first set of initial model parameters comprises:
 determining a temperature influence of the building equipment configured to heat the building space based on at least one zone temperature (ZNT) value and at least one outdoor air temperature (OAT) value;   determining some of the first set of model parameters with least squares and the determined temperature influence; and   determining some of the first set of model parameters based on the minimum difference of a plurality of ZNT values and a plurality of OAT values.   
     
     
         8 . The method of  claim 6 , wherein generating, with least squares, the second set of initial model parameters comprises:
 determining a temperature influence of the building equipment configured to cool the building space based on at least one zone temperature (ZNT) value and at least one outdoor air temperature (OAT) value;   determining some of the second set of parameters with least squares and the determined temperature influence; and   determining some of the second set of parameters based on a maximum difference of a plurality of ZNT values and a plurality of OAT values.   
     
     
         9 . The method of  claim 1 , further comprising generating, by the one or more processing circuits, the thermal plant model for the building space and the building equipment based on recorded outdoor ambient temperature (OAT) values, zone temperature (ZNT) values, states of the one or more heating outputs, and states of the one or more cooling outputs. 
     
     
         10 . The method of  claim 1 , further determining, via a Kalman filter, a temperature disturbance for the thermal plant model. 
     
     
         11 . A thermostat for a building space, the thermostat comprising:
 a processing circuit configured to:
 cause building equipment to heat or cool the building space via one or more heating outputs or one or more cooling outputs; 
 record the length of time that the processing circuit causes the building equipment to heat or cool the building space; 
 simulate a thermal plant model to determine a simulated runtime, wherein the thermal plant model is a thermal plant model of the building space and the building equipment; and 
 determine a number of hours saved based on the simulated runtime and the recorded length of time. 
   
     
     
         12 . The thermostat of  claim 11 , wherein the processing circuit is configured to identify the thermal plant model for the building space and the HVAC equipment based on recorded outdoor ambient temperature (OAT) values, zone temperature (ZNT) values, states of the one or more heating outputs, and states of the one or more cooling outputs. 
     
     
         13 . The thermostat of  claim 11 , wherein the processing circuit is configured to determine, via a Kalman filter, a temperature disturbance for the thermal plant model. 
     
     
         14 . The thermostat of  claim 11 , wherein the processing circuit is configured to:
 record a plurality of actual runtimes, wherein the actual runtimes are lengths of time that the processing circuit causes the HVAC equipment to heat or cool the building for a plurality of days; and   simulate the thermal plant model to determine a plurality of simulated runtimes for the plurality of days, wherein the thermal plant model is a thermal plant model of the building space and the HVAC equipment.   
     
     
         15 . The thermostat of  claim 14 , wherein the thermostat further comprises a user interface configured to display information to a user; and
 wherein the processing circuit is configured to cause the user interface to display the plurality of recorded actual runtimes for at least some of the plurality of days and the plurality of simulated runtimes for the at least some of the plurality of days via a graph.   
     
     
         16 . The thermostat of  claim 15 , wherein the graph displays hours of runtime on a first axis and the at least some of the plurality of days on a second axis. 
     
     
         17 . A system for determining energy usage of a thermostat for a building space, the thermostat comprising:
 a processing circuit configured to:
 cause building equipment to heat or cool the building space via one or more heating outputs or one or more cooling outputs; 
 record the length of time that the processing circuit causes the building equipment to heat or cool the building space; 
 send, via a network, the one or more heating outputs, the one or more cooling outputs, and a zone temperature to a remote device; 
 receive, via the network, a simulated runtime from the remote device, wherein the remote device determines simulated runtime based on a thermal plant model, wherein the thermal plant model of the building space and the building equipment; and 
 determine a number of hours saved based on the simulated runtime and the recorded length of time. 
   
     
     
         18 . The system of  claim 17 , wherein the system further comprises the remote device comprising a processing circuit, wherein the processing circuit is configured to:
 receive, via the network, the one or more heating outputs, the one or more cooling outputs, and a zone temperature from the thermostat;   determine the simulated runtime by:
 generating the thermal plant model for the building space and the HVAC equipment based on at least one ambient temperature (OAT) value, the at least one received zone temperature (ZNT) values, the one or more heating outputs, and the one or more cooling outputs; and 
 simulating the thermal plant model to determine the simulated runtime. 
   
     
     
         19 . The system of  claim 18 , wherein the processing circuit of the remote device is configured to determine, via a Kalman filter, a temperature disturbance for the thermal plant model. 
     
     
         20 . The method of  claim 2 , wherein the method further comprises updating and re-identifying the thermal plant model based on additional environmental data and additional control outputs of the thermostat collected over a period of time, wherein updating and re-identifying the thermal plant model adapts the thermal plant model to changes in the building equipment and seasons.