Air conditioner and control method thereof

Abstract

The present disclosure relates to an air conditioner including an outdoor unit and an indoor unit connected to the outdoor unit, wherein the outdoor unit includes: a compressor configured to compress a refrigerant, an outdoor heat exchanger configured to perform heat exchange between outdoor air and the refrigerant, a humidity sensor provided inside the outdoor unit and configured to measure a relative humidity inside the outdoor unit, an outdoor temperature sensor configured to measure an outdoor temperature, and a controller, comprising circuitry, configured to: determine an absolute humidity based on output of the humidity sensor, determine an outdoor relative humidity based on the absolute humidity and the outdoor temperature, determine a dew point temperature of the outdoor air based on the outdoor relative humidity and the outdoor temperature, and determine whether to perform a defrosting operation by comparing the dew point temperature and a temperature of the outdoor heat exchanger.

What is claimed is: 
     
         1 . An air conditioner comprising:
 an outdoor unit; and   an indoor unit connected to the outdoor unit,   wherein the outdoor unit comprises:   a compressor configured to compress a refrigerant;   an outdoor heat exchanger configured to perform heat exchange between outdoor air and the refrigerant;   a humidity sensor provided inside the outdoor unit and configured to measure a relative humidity inside the outdoor unit;   an outdoor temperature sensor configured to measure an outdoor temperature; and   a controller, comprising circuitry, configured to: determine an absolute humidity based on a dry bulb temperature and the relative humidity inside the outdoor unit measured by the humidity sensor, determine an outdoor relative humidity based on the absolute humidity and the outdoor temperature, and determine whether to cause the air conditioner to perform a defrosting operation based on the outdoor relative humidity and the outdoor temperature.   
     
     
         2 . The air conditioner according to  claim 1 , wherein
 the controller is configured to determine the outdoor relative humidity based on the absolute humidity and the outdoor temperature based on a specified time elapsing after determining the absolute humidity.   
     
     
         3 . The air conditioner according to  claim 1 , wherein
 the outdoor unit comprises:   a fan configured to blow outdoor air to the outdoor heat exchanger; and   a motor configured to transmit a rotational force to the fan.   
     
     
         4 . The air conditioner according to  claim 3 , wherein
 the controller is configured to determining the absolute humidity and the outdoor relative humidity by controlling the motor to rotate the fan before operating the compressor based on a heating operation signal being generated.   
     
     
         5 . The air conditioner according to  claim 3 , wherein
 the controller is configured to update the absolute humidity and the outdoor relative humidity by controlling the motor to rotate the fan based on a specified time elapsing after the compressor stops during a heating operation.   
     
     
         6 . The air conditioner according to  claim 1 , wherein
 the controller is configured to: determine a dew point temperature based on the outdoor relative humidity and the outdoor temperature, and determine whether to perform the defrosting operation by comparing the dew point temperature and a temperature of the outdoor heat exchanger.   
     
     
         7 . The air conditioner according to  claim 6 , wherein
 the controller is configured to control the air conditioner to perform the defrosting operation based on the temperature of the outdoor heat exchanger being equal to or lower than the dew point temperature.   
     
     
         8 . The air conditioner according to  claim 6 , wherein
 the controller is configured to control the air conditioner to perform the defrosting operation based on the temperature of the outdoor heat exchanger being equal to or lower than a temperature lower than the dew point temperature by a specified temperature.   
     
     
         9 . The air conditioner according to  claim 1 , wherein
 the controller is configured to control the air conditioner to maintain the defrosting operation until the temperature of the outdoor heat exchanger falls within a specified temperature range based on performing the defrosting operation.   
     
     
         10 . The air conditioner according to  claim 1 , wherein
 the humidity sensor is provided inside a control box of the outdoor unit.   
     
     
         11 . A method of controlling an air conditioner comprising an outdoor unit comprising an outdoor heat exchanger and an outdoor temperature sensor, and an indoor unit connected to the outdoor unit, wherein the method comprises:
 determining an absolute humidity based on a dry bulb temperature and a relative humidity inside the outdoor unit measured by a humidity sensor provided inside the outdoor unit to measure the relative humidity inside the outdoor unit;   determining an outdoor relative humidity based on the absolute humidity and an outdoor temperature; and   determining whether to perform a defrosting operation based on the outdoor relative humidity and the outdoor temperature.   
     
     
         12 . The method according to  claim 11 , wherein
 the determining of the outdoor relative humidity comprises:   determining the outdoor relative humidity based on the absolute humidity and the outdoor temperature based on a specified time elapsing after determining the absolute humidity.   
     
     
         13 . The method according to  claim 12 , wherein
 the outdoor unit comprises:   a fan configured to blow outdoor air to the outdoor heat exchanger; and   a motor configured to transmit a rotational force to the fan.   
     
     
         14 . The method according to  claim 13 , wherein
 the determining of the absolute humidity and the outdoor relative humidity comprises:   determining the absolute humidity and the outdoor relative humidity by controlling the motor to rotate the fan before operating a compressor based on a heating operation signal being generated.   
     
     
         15 . The method according to  claim 13 , wherein
 the determining of the absolute humidity and the outdoor relative humidity comprises:   updating the absolute humidity and the outdoor relative humidity by controlling the motor to rotate the fan based on a specified time elapsing after a compressor stops during a heating operation.