Thermostat and method for operating in either a normal or dehumidification mode

Abstract

The inventive thermostat provides for sensing the temperature and humidity within the space, and responsively controlling the operation of an air conditioning compressor and blower to maintain the desired temperature and humidity. In a first mode, the thermostat operates the compressor at maximum capacity and the blower at less than maximum capacity to provide dehumidification when the humidity level is above a set point. In a second mode, the thermostat operates the compressor and blower at maximum capacity to provide full cooling capacity when the sensed temperature is more than a predetermined amount above the desired temperature setting. The thermostat is also configured to automatically switch from the first mode of operation to the second mode of operation.

1 . A digital thermostat for controlling the operation of an air conditioner having a variable capacity compressor and blower, comprising: 
 a temperature sensing means for providing a signal indicating the temperature of a space,    a humidity sensing means for providing a signal indicating the humidity level within the space;    a processor for receiving signals from the temperature sensing and humidity sensing means and for sending signals for controlling the operation of the compressor and blower;    the processor operative in a first mode to operate the compressor and the blower at less than full capacity when the sensed humidity is above the desired humidity set point and the sensed temperature is not more than a predetermined amount above the humidity set point; and    the processor operative in a second mode to operate the compressor at full capacity and the blower at full capacity when the sensed temperature is more than a predetermined amount above the desired temperature set point.    
   
   
       2 . The digital thermostat of  claim 1 , wherein the processor is operative in a third mode to operate the compressor at less than full capacity and the blower at full capacity when the sensed temperature is above the temperature set point and the sensed humidity is below the desired humidity set point.  
   
   
       3 . The digital thermostat of  claim 1 , wherein the variable capacity compressor comprises a plurality of selectable speeds.  
   
   
       4 . The digital thermostat of  claim 3 , where the variable capacity blower comprises a plurality of selectable speeds.  
   
   
       5 . The digital thermostat of  claim 3 , wherein the variable capacity blower comprises a continuously variable range of speeds.  
   
   
       6 . The digital thermostat of  claim 5 , wherein the processor switches from the first mode of operation to the second mode of operation when the sensed humidity is above the desired humidity set point and the sensed temperature rises more than a predetermined amount above the temperature set point.  
   
   
       7 . The digital thermostat of  claim 6 , wherein the predetermined amount is about three degrees Fahrenheit.  
   
   
       8 . The digital thermostat of  claim 4 , further comprising a display that displays the mode of operation as Dehumidification when the blower is operating at less than full capacity and the compressor is operating at full capacity.  
   
   
       9 . A digital thermostat for controlling the operation of an air conditioner having a multi-speed compressor and blower, comprising: 
 a temperature sensing means for providing a signal indicating the temperature of a space,    a humidity sensing means for providing a signal indicating the humidity level within the space;    a processor for receiving signals from the temperature sensing and humidity sensing means and for sending signals for controlling the operation of the compressor and blower, wherein the processor responsively operates the compressor at the maximum speed and operates the blower at less than the maximum speed when the sensed humidity is above the desired humidity set point and the sensed temperature is within a predetermined amount above the temperature set point; and    wherein the processor responsively operates the compressor at the maximum speed and the blower at the maximum speed when the sensed temperature is more than a predetermined amount above the desired temperature set point.    
   
   
       10 . The digital thermostat of  claim 9 , wherein the processor operates the compressor at less than the maximum speed and the blower at the maximum speed when the sensed temperature is above the temperature set point and the sensed humidity is below the desired humidity set point.  
   
   
       11 . The digital thermostat of  claim 9 , wherein the compressor comprises at least two levels of operation.  
   
   
       12 . The digital thermostat of  claim 9 , wherein the compressor includes a motor that comprises at least two speeds of operation.  
   
   
       13 . The digital thermostat of  claim 12 , wherein the blower includes a motor that comprises at least two speeds of operation.  
   
   
       14 . The digital thermostat of  claim 13 , wherein the processor switches the blower from a less than maximum speed to the maximum speed when the sensed humidity is above the desired humidity set point and the sensed temperature rises more than a predetermined amount above the temperature set point.  
   
   
       15 . The digital thermostat of  claim 14 , wherein the predetermined amount is about three degrees Fahrenheit.  
   
   
       16 . The digital thermostat of  claim 14 , further comprising a display that displays the mode of operation as Dehumidification when the blower is operating at less than full capacity and the compressor is operating at full capacity.  
   
   
       17 . A digital thermostat in combination with a variable speed compressor and a variable speed blower, the combination comprising: 
 a temperature sensing means for providing a signal indicating the temperature of a space,    a humidity sensing means for providing a signal indicating the humidity level within the space;    a processor for receiving signals from the temperature sensing and humidity sensing means and for sending signals for controlling the operation of the compressor and blower, wherein the processor responsively operates the compressor at the maximum speed and operates the blower at a speed that is less than the maximum when the sensed humidity is above the desired humidity set point and the sensed temperature is within a predetermined amount above the temperature set point; and    wherein the processor responsively operates the compressor at the maximum speed and the blower at the maximum speed when the sensed temperature is more than a predetermined amount above the desired temperature set point.    
   
   
       18 . The combination of  claim 17 , wherein the processor switches from the first mode of operation to the second mode of operation when the sensed humidity is above the desired humidity set point and the sensed temperature rises more than a predetermined amount above the temperature set point.  
   
   
       19 . A method of controlling the operation of thermostat for an air conditioner having a variable speed compressor and blower, a humidity sensor and a temperature sensor, the method comprising the steps of: 
 sensing the temperature of the space to be maintained;    sensing the humidity level of the space to be maintained;    determining if the sensed humidity level is above the desired humidity set point;    determining if the sensed temperature is above the temperature set point but less than a predetermined amount above the temperature set point;    responsively establishing operation of the compressor at full capacity and operation of the blower at less than full capacity when the sensed humidity is above the desired humidity set point and the sensed temperature is above the temperature set point but less than a predetermined amount above the temperature set point.    
   
   
       20 . The method of  claim 19 , further comprising the steps of establishing operation of the compressor at full capacity and the blower at full capacity when the sensed temperature rises more than a predetermined amount above the temperature set point.