HVAC&R humidity control system and method

Abstract

A controller controls operation of a HVAC&R device to reduce an interior humidity level for a structure to provide comfort for occupants of the structure. The controller includes a first sensor for sensing a temperature inside a structure and a second sensor for sensing a humidity level inside the structure. A controller is responsive to the first and second sensors for the HVAC&R device operating in a cooling mode to reduce the humidity level inside the structure. The controller calculates a temperature correction to a predetermined temperature setting for the HVAC&R device, the temperature correction calculation being obtained by subtracting the sensed humidity level from a predetermined humidity level and dividing the result by a predetermined factor. The controller initiates operation of the HVAC&R device when the sum of the sensed temperature and the temperature correction is greater than the predetermined temperature.

1 . A method for controlling humidity in a structure with a HVAC&R system, the method comprising the steps of: 
 sensing a temperature and a humidity level inside a structure;    calculating a temperature correction value in response to a predetermined humidity level, the sensed humidity level and a predetermined humidity sensitivity factor;    comparing a predetermined temperature setting for a HVAC&R device with the sum of the sensed temperature and the temperature correction value; and    initiating operation of the HVAC&R device to reduce the humidity level inside the structure when the sum of the sensed temperature and the temperature correction value is greater than the predetermined temperature setting.    
     
     
         2 . The method of  claim 1  further comprising the step of selecting the predetermined humidity level, the predetermined temperature setting and the predetermined humidity sensitivity factor.  
     
     
         3 . The method of  claim 1  wherein the predetermined humidity sensitivity factor is between about 1 and about 10.  
     
     
         4 . The method of  claim 1  wherein the predetermined humidity level is greater than about 45 percent.  
     
     
         5 . The method of  claim 1  further including, after the step of initiating operation of the HVAC&R device, the step of repeating the steps of sensing a temperature and a humidity level, calculating a temperature correction value, comparing a predetermined temperature setting and initiating operation of the HVAC&R device.  
     
     
         6 . The method of  claim 1  wherein the step of calculating a temperature correction value includes the steps of: 
 subtracting a predetermined humidity level from the sensed humidity level to generate a humidity difference;    dividing the humidity difference by the predetermined humidity sensitivity factor to generate the temperature correction value.    
     
     
         7 . The method of  claim 1  wherein the step of calculating a temperature correction value includes the steps of: 
 comparing the temperature correction value to a maximum temperature correction;    changing the temperature correction value to the maximum temperature correction in response to the temperature correction value being greater than the maximum temperature correction.    
     
     
         8 . A controller for controlling humidity in a structure with a HVAC&R system, the controller comprising: 
 a first sensor for sensing a temperature inside a structure and a second sensor for sensing a humidity level inside the structure;    a controller responsive to the first and second sensors for a HVAC&R device, the controller calculating a temperature correction value in response to a predetermined humidity level, the sensed humidity level and a predetermined humidity sensitivity factor; and    wherein the controller initiating operation of the HVAC&R device to reduce the humidity level inside the structure when the sum of the sensed temperature and the temperature correction value is greater than the predetermined temperature setting.    
     
     
         9 . The controller of  claim 8  wherein the predetermined humidity sensitivity factor is between about 1 to about 10.  
     
     
         10 . The controller of  claim 8  wherein the predetermined humidity level is greater than about 45 percent.  
     
     
         11 . The controller of  claim 8  wherein the structure is a commercial building.  
     
     
         12 . The controller of  claim 8  wherein the structure is a residential building.  
     
     
         13 . The controller of  claim 8  wherein the temperature correction value is calculated by subtracting a predetermined humidity level from the sensed humidity level to generate a humidity difference, and then dividing the humidity difference by the predetermined humidity sensitivity factor to generate the temperature correction value.  
     
     
         14 . The controller of  claim 8  wherein the temperature correction value is calculated by comparing the temperature correction value to a maximum temperature correction, and then changing the temperature correction value to the maximum temperature correction in response to the temperature correction value being greater than the maximum temperature correction.