Clothes dryer and anti-freezing driving method

Abstract

A clothes dryer including a drum; a flow passage to guide air inside of the drum to outside of the drum, and then back inside of the drum; a heat pump system to heat the air to flow back inside of the drum, the heat pump system including a compressor, a condenser, an expansion valve, and an evaporator through which refrigerant circulates; and a controller configured to, in response to receiving a command for an anti-freeze mode operation, control the clothes dryer to perform a heating operation in which the compressor is driven for a first period of time, after the compressor is driven for the first period of time, the compressor is stopped for a second period of time, and the driving of the compressor for the first period of time and the stopping of the compressor for the second period of time is repeated a plurality of times.

1 . A clothes dryer, comprising:
 a drum configured to accommodate an object to be dried;   a flow passage configured to guide air discharged from an inside of the drum to an outside of the drum, and then to be introduced back into the inside of the drum;   a heat pump system configured to heat the air that is to be introduced back into the inside of the drum, the heat pump system including a compressor, a condenser, an expansion valve, and an evaporator through which a refrigerant circulates; and   a controller configured to, in response to receiving a command for an anti-freeze mode operation, control the clothes dryer to perform a heating operation in which:
 the compressor is driven for a first period of time, 
 after the compressor is driven for the first period of time, the compressor is stopped for a second period of time, and 
 the driving of the compressor for the first period of time and the stopping of the compressor for the second period of time is repeated a plurality of times. 
   
     
     
         2 . The clothes dryer of  claim 1 , further comprising:
 a temperature acquisition unit configured to obtain an external temperature value; and   a control table including a plurality of operation frequencies for the compressor, the plurality of operation frequencies corresponding to a plurality of external temperatures, respectively, in relation to the anti-freeze mode operation,   wherein the controller is configured to, in response to receiving the command for the anti-freeze mode operation, obtain a corresponding operation frequency among the plurality of operation frequencies from the control table based on the obtained external temperature value, and   the driving of the compressor for the first period of time includes driving the compressor according to the obtained corresponding operation frequency.   
     
     
         3 . The clothes dryer of  claim 2 , further comprising:
 a refrigerant temperature sensor configured to obtain a temperature of refrigerant discharged from the compressor,   wherein the control table includes a plurality of target temperatures for the refrigerant, the plurality of target temperatures corresponding to the plurality of external temperatures, respectively, and   the driving of the compressor for the first period of time includes:
 driving the compressor according to the obtained operation frequency until the obtained temperature of the refrigerant reaches a corresponding target temperature among the plurality of target temperatures, and 
 after the obtained temperature of the refrigerant reaches the corresponding target temperature, driving the compressor according to an adjusted operation frequency so that the obtained temperature of the refrigerant remains at the corresponding target temperature. 
   
     
     
         4 . The clothes dryer of  claim 1 , further comprising:
 a temperature acquisition unit configured to obtain an external temperature value;   a heater installed on the flow passage; and   a control table including a plurality of turn-on/off conditions for the heater, the plurality of turn-on/off conditions corresponding to a plurality of external temperatures respectively, in relation to the anti-freeze mode operation,   wherein the controller is configured to:
 in response to receiving the command for the anti-freeze mode operation, obtain a corresponding turn-on/off condition among the plurality of turn-on/off conditions for the heater from the control table based on the obtained external temperature value, and 
 repeatedly turn on/off the heater according to the obtained corresponding turn-on/off condition while the compressor is driven for the first period of time. 
   
     
     
         5 . The clothes dryer of  claim 4 , further comprising:
 a refrigerant temperature sensor configured to obtain a temperature of refrigerant discharged from the compressor,   wherein the corresponding turn-on/off condition for the heater is determined based on the obtained temperature of the refrigerant.   
     
     
         6 . The clothes dryer of  claim 1 , wherein
 the first period of time is shorter than the second period of time.   
     
     
         7 . The clothes dryer of  claim 1 , wherein
 the controller is configured to, in response to receiving the command for the anti-freeze mode operation, control the clothes dryer to perform a preparatory operation of waiting for a predetermined time with the compressor turned off before starting the heating operation.   
     
     
         8 . The clothes dryer of  claim 7 , further comprising:
 a blower fan configured to cause air to move in the flow passage,   wherein the controller is configured to control the blower fan to be driven while the preparatory operation is performed.   
     
     
         9 . The clothes dryer of  claim 1 , further comprising:
 a heater installed on the flow passage; and   a blower fan configured to cause air to move in the flow passage,   wherein the controller is configured to control the blower fan to be driven with the compressor and the heater turned off for a predetermined time after the heating operation is performed the plurality of times.   
     
     
         10 . The clothes dryer of  claim 1 , further comprising:
 a temperature acquisition unit configured to obtain an external temperature value,   wherein the controller is configured to:
 monitor the obtained external temperature value and, 
 upon determining that there is a risk of freezing, generate a message indicating the risk of freezing. 
   
     
     
         11 . The clothes dryer of  claim 10 , wherein
 the temperature acquisition unit includes at least one of a temperature sensor installed on the clothes dryer and a communication unit configured to obtain the external temperature value from an external server through a communication network.   
     
     
         12 . The clothes dryer of  claim 10 , wherein
 the message includes an inquiry as to whether to perform the anti-freeze mode operation.   
     
     
         13 . The clothes dryer of  claim 10 , further comprising:
 a display configured to output information for the user; and   an input unit configured to receive an input from the user,   wherein the controller is configured to:
 control the message to be displayed through the display, and 
 receive the command from a user for the anti-freeze mode operation through the input unit. 
   
     
     
         14 . The clothes dryer of  claim 10 , further comprising:
 a communication unit configured to communicate with a pre-registered user equipment (UE) through a communication network,   wherein the controller is configured to:
 control the message to be transmitted to the UE through the communication unit, and 
 receive the command for the anti-freeze mode operation from the UE through the communication unit. 
   
     
     
         15 . A method of performing an anti-freeze mode operation in a clothes dryer, the clothes dryer including a temperature sensor, a drum configured to accommodate an object to be dried, a flow passage configured to guide air discharged from an inside of the drum to an outside of the drum, and then to be introduced back into the inside of the drum, a heat pump system configured to heat the air that is to be introduced back into the inside of the drum, the heat pump system including a compressor, a condenser, an expansion valve, and an evaporator through which a refrigerant circulates, a blower fan configured to cause air to move in the flow passage, a motor configured to rotate the blower fan, and a heater configured to heat the air that is to be introduced back into the inside of the drum, the method comprising:
 performing a heating operation including:
 driving the motor, the compressor, and the heater for a first period time based on an operation specification determined according to a temperature measured by the temperature sensor, 
 after driving the motor, the compressor, and the heater for the first period of time, stopping the motor, the compressor, and the heater for a second period of time, and 
 repeating, for a plurality of times, the driving of the motor, the compressor, and the heater for the first period of time and the stopping of the motor, the compressor, and the heater for the second period of time; and 
   after performing the heating operation, performing a cooling operation in which the motor is driven to rotate the fan for a third period of time with the compressor and the heater stopped.