System and method for controlling ventilation system based upon humidity detection

Abstract

A system and method for controlling activation and deactivation of an exhaust system for ventilating an enclosed space, such as a bathroom. The system includes a humidity sensor, a memory element, and a processing element. The sensor measures a humidity value in the space, and the memory element stores that value along with a series of previously measured humidity values. The memory also stores a look-up table which specifies activation and deactivation criteria for the exhaust system based on the measured humidity value and a normal humidity value. The processing element calculates the normal humidity value based on a weighted average of the stored series of humidity values, consults the look-up table, and controls the exhaust system as specified by the look-up table. The measured humidity value is added to the stored series of values at a first interval, and the normal humidity value is re-calculated at a second interval.

Having thus described one or more embodiments of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following: 
     
         1 . A system for controlling activation and deactivation of an exhaust system for ventilating an enclosed space, the system comprising:
 a humidity sensor configured to measure a humidity value in the enclosed space;   a memory element configured to receive and store the measured humidity value along with a series of previously measured humidity values, and to store a look-up table; and   a processing element configured to calculate a normal humidity value based on a weighted average of the stored series of previously measured humidity values, and to consult the look-up table which specifies activation and deactivation criteria for the exhaust system based on the measured humidity value and the normal humidity value, and to cause the exhaust system to activate or deactivate as specified by the look-up table.   
     
     
         2 . The system as set forth in  claim 1 , the exhaust system including an exhaust fan for drawing air out of the enclosed space, a motor for driving the exhaust fan, and a grill for shielding access to an interior of the exhaust system. 
     
     
         3 . The system as set forth in  claim 1 , wherein the enclosed space is a bathroom, and the exhaust system is installed in a ceiling of the bathroom. 
     
     
         4 . The system as set forth in  claim 1 , wherein the humidity sensor is positioned near the exhaust system. 
     
     
         5 . The system as set forth in  claim 1 , wherein the humidity sensor is positioned remote from the exhaust system. 
     
     
         6 . The system as set forth  claim 1 , wherein the measured humidity value is added to the series of previously measured humidity values and stored in the memory element at a first interval of between ten and thirty seconds. 
     
     
         7 . The system as set forth  claim 1 , wherein the measured humidity value is added to the series of previously measured humidity values and stored in the memory element at a first interval of between fifteen and twenty-five seconds. 
     
     
         8 . The system as set forth in  claim 1 , wherein the normal humidity value is calculated based on the weighted average of the series of previously measured humidity values stored in the memory element over a second interval of between twenty and forty seconds. 
     
     
         9 . The system as set forth in  claim 8 , wherein while the exhaust system is activated, the normal humidity value is not re-calculated. 
     
     
         10 . The system as set forth in  claim 1 , wherein the normal humidity value is calculated based on the weighted average of the series of previously measured humidity values stored in the memory element over a second interval of thirty seconds. 
     
     
         11 . The system as set forth in  claim 1 , wherein if the exhaust system remains activated for more than a time limit, the processing element deactivates the exhaust system even if the measured humidity value does not satisfy the deactivation criteria specified in the look-up table, and the system resets by determining a new normal humidity value. 
     
     
         12 . The system as set forth in  claim 1 , further including an occupancy sensor configured to determine whether the enclosed space is occupied, and the processing element is further configured to control activation and deactivation of the exhaust system only when the enclosed space is occupied. 
     
     
         13 . A system for controlling activation and deactivation of an exhaust fan for ventilating a bathroom, the system comprising:
 a humidity sensor configured to measure a humidity value in the bathroom;   a memory element configured to receive and store at a first interval of between ten and thirty seconds the measured humidity value along with a series of previously measured humidity values, and to store a look-up table; and   a processing element configured to calculate a normal humidity value based on a weighted average of the series of previously measured humidity values stored in the memory element over a second interval of between twenty and forty seconds, and to consult the look-up table which specifies activation and deactivation criteria for the exhaust fan based on the measured humidity value and the normal humidity value, and to cause the exhaust fan to activate or deactivate as specified by the look-up table.   
     
     
         14 . The system as set forth in  claim 13 , wherein while the exhaust fan is activated, the normal humidity value is not re-calculated. 
     
     
         15 . The system as set forth in  claim 13 , wherein if the exhaust fan remains activated for more than a time limit, the processing element deactivates the exhaust fan even if the measured humidity value does not satisfy the deactivation criteria specified in the look-up table, and the system resets by determining a new normal humidity value. 
     
     
         16 . The system as set forth in  claim 13 , further including an occupancy sensor configured to determine whether the bathroom is occupied, and the processing element is further configured to control activation and deactivation of the exhaust fan only when the enclosed space is occupied. 
     
     
         17 . A method for controlling activation and deactivation of an exhaust fan for ventilating a bathroom, the method comprising:
 measuring with a humidity sensor a humidity value in the bathroom;   receiving and storing in an electronic memory element at a first interval of between ten and thirty seconds the measured humidity value along with a series of previously measured humidity values; and   calculating with an electronic processing element a normal humidity value based on a weighted average of the series of previously measured humidity values stored in the electronic memory element over a second interval of between twenty and forty seconds;   consulting by the electronic processing element a look-up table stored in the electronic memory element which specifies activation and deactivation criteria for the exhaust fan based on the measured humidity value and the calculated normal humidity value; and   causing by the electronic processing element the exhaust fan to activate or deactivate as specified by the look-up table.   
     
     
         18 . The method as set forth in  claim 17 , wherein while the exhaust fan is activated, the normal humidity value is not re-calculated. 
     
     
         19 . The method as set forth in  claim 17 , further including, if the exhaust system remains activated for more than a time limit—
 deactivating by the electronic processing element the exhaust fan even if the measured humidity value does not satisfy the deactivation criteria specified in the look-up table; and 
 resetting by the electronic processing element by calculating a new normal humidity value. 
 
     
     
         20 . The method as set forth in  claim 17 , further including—
 determining with an occupancy sensor whether the bathroom is occupied; and 
 controlling by the electronic processing element activation and deactivation of the exhaust fan only when the bathroom is occupied.