Determining window efficiency setting for use in humidity control of a building

Abstract

A controller for operating HVAC equipment of a building having one or more windows. The HVAC equipment includes a heater and a humidifier. The controller receives an indoor temperature and an outdoor temperature, determines a thermal efficiency of the building based on the indoor temperature, the outdoor temperature and control signals provided to the heater indicative of a thermal demand on the heater, determines a window efficiency setting based on the thermal efficiency, determines a humidity threshold based on the window efficiency setting and the outdoor temperature, and controls the humidifier of the building to not raise the humidity in the building above the humidity threshold.

What is claimed is: 
     
         1 . A controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, the controller is configured to:
 receive an indoor temperature within the building and an outdoor temperature outside of the building;   determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and one or more control signals provided to the heater that are indicative of a thermal demand on the heater;   determine a window efficiency setting based at least in part on the determined measure of thermal efficiency;   determine a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature; and   control the humidifier of the building to not raise the humidity in the building above the humidity threshold.   
     
     
         2 . The controller of  claim 1 , wherein the measure of thermal efficiency of the building is determined while the heater is controlling the indoor temperature of the building in accordance with a constant temperature setpoint. 
     
     
         3 . The controller of  claim 1 , wherein the heater comprises a modulating furnace with a modulating heat output that is modulated by a control input, and wherein the one or more control signals include the control input. 
     
     
         4 . The controller of  claim 3 , wherein the control input to the modulating furnace is provided by a PI controller. 
     
     
         5 . The controller of  claim 1 , wherein the heater is cycled on and off by a heater relay output to control the indoor temperature of the building in accordance with a temperature setpoint, wherein the one or more control signals include the heater relay output. 
     
     
         6 . The controller of  claim 5 , wherein a cycle rate of the heater relay output is indicative of the thermal demand on the heater. 
     
     
         7 . The controller of  claim 1 , wherein the controller comprises a thermostat located within the building. 
     
     
         8 . The controller of  claim 1 , wherein at least part of the controller is implemented in a server remote from the building. 
     
     
         9 . A controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, the controller is configured to:
 receive an indoor temperature within the building and an outdoor temperature outside of the building;   cycle the heater ON and OFF to control the indoor temperature of at least part of the building in accordance with a temperature schedule, wherein the temperature schedule includes a plurality of time periods each with a corresponding temperature setpoint, and wherein the temperature schedule includes a comfort time period with a comfort temperature setpoint followed by a setback time period immediately following the comfort time period with a lower setback temperature setpoint;   determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and a rate of change of the indoor temperature during a sensing period extending from after the heater is cycled OFF at the end of the comfort time period to before the indoor temperature reaches the lower setback temperature setpoint of the immediately following setback time period;   determine a window efficiency setting based at least in part on the determined measure of thermal efficiency;   determine a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature; and   control the humidifier of the building to not raise the humidity in the building above the humidity threshold.   
     
     
         10 . The controller of  claim 9 , wherein the controller is configured to determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and the rate of change of the indoor temperature during a period after a user manually adjusts a current temperature setpoint downward to a lower temperature setpoint to before the indoor temperature reaches the lower temperature setpoint. 
     
     
         11 . The controller of  claim 9 , wherein the heater remains OFF during the sensing period. 
     
     
         12 . The controller of  claim 9 , wherein the controller comprises a thermostat located within the building. 
     
     
         13 . The controller of  claim 9 , wherein at least part of the controller is implemented in a server remote from the building. 
     
     
         14 . A controller for operating HVAC equipment of a building having one or more windows, the HVAC equipment including a heater and a humidifier, the controller is configured to:
 receive an indoor temperature within the building and an outdoor temperature outside of the building;   determine a measure of thermal efficiency of the building based at least in part on the indoor temperature, the outdoor temperature and a sensed parameter that is related to a rate of heat loss of the building;   receive information from a user regarding the one or more windows;   determine a window efficiency setting based at least in part on the determined measure of thermal efficiency and the information received from the user regarding the one or more windows;   determining a humidity threshold based at least in part on the window efficiency setting and the outdoor temperature; and   controlling a humidifier of the building to not raise the humidity in the building above the humidity threshold.   
     
     
         15 . The controller of  claim 14 , wherein the information received from the user includes one or more of a total number of windows in the building, a number of window panes in the windows in the building, a manufacturer of the windows in the building, a type of the windows in the building, a model number of the windows in the building, and an age of the windows of the building. 
     
     
         16 . The controller of  claim 14 , further comprising receive information from the user regarding the building, and determine the window efficiency setting based at least in part on the determined measure of thermal efficiency, the information received from the user regarding the one or more windows and the information received from the user regarding the building. 
     
     
         17 . The controller of  claim 16 , wherein the information received from the user regarding the building includes one or more of a building square feet, a R-value of walls of the building, a wall thickness of the building, and an age of the building. 
     
     
         18 . The controller of  claim 14 , further comprising receive information from a public database regarding the building, and determine the window efficiency setting based at least in part on the determined measure of thermal efficiency, the information received from the user regarding the one or more windows and the information received from the public database regarding the building. 
     
     
         19 . The controller of  claim 14 , wherein the controller comprises a thermostat located within the building. 
     
     
         20 . The controller of  claim 14 , wherein at least part of the controller is implemented in a server remote from the building.