Defrosting method of air conditioner

Abstract

A defrosting method of an air conditioner is disclosed. The air conditioner has an indoor unit having an indoor heat-exchanger, an indoor blower fan, an auxiliary heater, an outdoor unit having an outdoor heat-exchanger, a compressor, an expansion device, and an outdoor blower fan, and a four-way valve to selectively switch a circulation direction of a refrigerant between the indoor unit and the outdoor unit such that the air conditioner is operated in a heating cycle when the four-way valve is turned off and the air conditioner is operated in a refrigerating cycle when the four-way valve is turned on. The defrosting method is selectively determined according to the number of the heating cycles of the air conditioner.

1 . A defrosting method of an air conditioner comprising: an indoor unit including an indoor heat-exchanger, an indoor blower fan, an auxiliary heater; an outdoor unit including an outdoor heat-exchanger, a compressor, an expansion device, and an outdoor blower fan; and a four-way valve to selectively switch a circulation direction of a refrigerant between the indoor unit and the outdoor unit such that the air conditioner is operated in a heating cycle when the four-way valve is turned off and the air conditioner is operated in a refrigerating cycle when the four-way valve is turned on,
 the defrosting method being selectively determined according to the number of the heating cycles of the air conditioner.   
   
   
       2 . The defrosting method of an air conditioner according to  claim 1 , comprising:
 checking the number of the heating cycles of the air conditioner;   determining whether a defrosting operation is to be started or not according to a defrosting operation starting condition based on the number of the heating cycles;   firstly operating the air conditioner in the refrigerating cycle for a minimal defrosting time when the defrosting operation starting condition is satisfied in the determining; and   re-determining whether the defrosting operation is finished or not according to a defrosting operation finishing condition based on the number of the heating cycles.   
   
   
       3 . The defrosting method of an air conditioner according to  claim 2 , wherein, in the checking, when the number of the heating cycles is equal to or less than 2, the defrosting operation starting condition comprises a case when the compressor is operated over a first accumulated driving time and pipe temperature of the outdoor heat-exchanger is equal to or less than a first freezing temperature. 
   
   
       4 . The defrosting method of an air conditioner according to  claim 3 , further comprising switching the operation cycle of the air conditioner to the refrigerating cycle when the defrosting operation starting condition is satisfied. 
   
   
       5 . The defrosting method of an air conditioner according to  claim 4 , wherein, in the switching the operation cycle to the refrigerating cycle, the compressor and the outdoor blower fan are switched to be turned off, the four-way valve is switched from a turning-off state to a turning-on state for a predetermined time period, and the auxiliary heater and the indoor blower fan are turned on when an indoor temperature is equal to or less than a predetermined temperature. 
   
   
       6 . The defrosting method of an air conditioner according to  claim 3 , wherein, in the firstly operating, the compressor and the four-way valve are turned on, and the auxiliary heater, the indoor blower fan, and the outdoor blower fan are turned off. 
   
   
       7 . The defrosting method of an air conditioner according to  claim 3 , wherein the defrosting operation finishing condition comprises a case when the pipe temperature of the outdoor heat-exchanger is equal to or greater than a first melting point. 
   
   
       8 . The defrosting method of an air conditioner according to  claim 3 , further comprising carrying out a heating operation after the firstly operating when the defrosting operation finishing condition is satisfied. 
   
   
       9 . The defrosting method of an air conditioner according to  claim 3 , further comprising:
 secondly operating the air conditioner in the refrigerating cycle until the defrosting operation finishing condition is satisfied when the defrosting operation finishing condition is not satisfied; and   switching the operation cycle of the air conditioner to the heating operation.   
   
   
       10 . The defrosting method of an air conditioner according to  claim 9 , wherein the secondly operating is not carried out without exceeding a first additional driving time, and
 the defrosting method further comprising switching the operation cycle of the air conditioner to the heating operation regardless of the defrosting operation finishing condition when the defrosting operation finishing condition is not satisfied during the first additional driving time.   
   
   
       11 . The defrosting method of an air conditioner according to  claim 9 , wherein, in the secondly operating, the compressor, the four-way valve, and the outdoor blower fan are tuned on, and the auxiliary heater and the indoor blower fan are turned off. 
   
   
       12 . The defrosting method of an air conditioner according to  claim 8 , wherein, in the switching the operation cycle to the heating operation, the compressor and the outdoor blower fan are turned off, the four-way valve is switched from the turning-on state to the turning-off state for a predetermined time period, and the auxiliary heater and the indoor blower fan are turned on when the indoor temperature is equal to or less than the predetermined temperature. 
   
   
       13 . The defrosting method of an air conditioner according to  claim 2 , wherein, in the checking, the defrosting operation starting condition, when the number of the heating cycles is equal to or greater than 3 and equal to or less than 5, comprises a case when the compressor is operated over for a second accumulated driving time and the pipe temperature of the outdoor heat-exchanger is equal to or less than a second freezing temperature. 
   
   
       14 . The defrosting method of an air conditioner according to  claim 13 , further comprising switching the operation cycle of the air conditioner to the refrigerating cycle when the defrosting operation starting condition is satisfied. 
   
   
       15 . The defrosting method of an air conditioner according to  claim 13 , further comprising:
 switching the operation cycle of the air conditioner to the defrosting operation after performing the heating operation for an additional heating time when the pipe temperature of the outdoor heat-exchanger is under the second freezing temperature by measuring the pipe temperature of the outdoor heat-exchanger at a predetermined time interval when the pipe temperature of the outdoor heat-exchanger is equal to or greater than the second freezing temperature after the compressor is operated over for the second accumulated driving time at the defrosting operation starting condition.   
   
   
       16 . The defrosting method of an air conditioner according to  claim 14 , wherein, in the switching the operation cycle to the defrosting operation, the compressor and the outdoor blower fan are turned off, the four-way valve is switched from the turning-off state to the turning-on state for a predetermined time period, and the auxiliary heater and the indoor blower fan are turned on when the indoor temperature is equal to or less than the predetermined temperature. 
   
   
       17 . The defrosting method of an air conditioner according to  claim 13 , wherein, in the firstly operating, the compressor and the four-way valve are turned on, and the auxiliary heater, the indoor blower fan, and the outdoor blower fan are turned off. 
   
   
       18 . The defrosting method of an air conditioner according to  claim 14 , wherein the defrosting operation finishing condition comprises a case when the pipe temperature of the outdoor heat-exchanger is equal to or greater than a second melting point. 
   
   
       19 . The defrosting method of an air conditioner according to  claim 13 , further comprising switching the operation cycle of the air conditioner from the firstly operating to the heating operation when the defrosting operation finishing condition is satisfied. 
   
   
       20 . The defrosting method of an air conditioner according to  claim 13 , further comprising:
 secondly operating the air conditioner in the refrigerating cycle until the defrosting operation finishing condition is satisfied when the defrosting operation finishing condition is not satisfied; and   switching the operation cycle of the air conditioner to the heating operation.   
   
   
       21 . The defrosting method of an air conditioner according to  claim 20 , wherein the secondly operating is not carried out without exceeding a second additional driving time, and
 the defrosting method further comprising switching the operation cycle of the air conditioner to the heating operation regardless of the defrosting operation finishing condition when the defrosting operation finishing condition is not satisfied during the second additional driving time.   
   
   
       22 . The defrosting method of an air conditioner according to  claim 20 , wherein, in the secondly operating, the compressor, the four-way valve, and the outdoor blower fan are tuned on, and the auxiliary heater and the indoor blower fan are turned off. 
   
   
       23 . The defrosting method of an air conditioner according to  claim 19 , wherein, in the switching the operation cycle to the heating operation, the compressor and the outdoor blower fan are turned off, the four-way valve is switched from the turning-on state to the turning-off state for a predetermined time period, and the auxiliary heater and the indoor blower fan are turned on when the indoor temperature is equal to or less than the predetermined temperature. 
   
   
       24 . The defrosting method of an air conditioner according to  claim 2 , wherein, in the checking, when the number of the heating cycles is equal to or greater than 6, the defrosting operation starting condition comprises a case when the compressor is operated over for a third accumulated driving time and pipe temperature of the outdoor heat-exchanger is equal to or less than a third freezing temperature. 
   
   
       25 . The defrosting method of an air conditioner according to  claim 24 , wherein, in the firstly operating, the compressor is turned off, the four-way valve is switched from a turning-off state to a turning-on state for a predetermined time period, the indoor blower fan and the outdoor blower fan are turned on, and the auxiliary heater is turned on when an indoor temperature is equal to or less than a predetermined temperature. 
   
   
       26 . The defrosting method of an air conditioner according to  claim 24 , wherein the defrosting operation finishing condition comprises a case when a pipe temperature of the outdoor heat-exchanger is equal to or greater than a third melting point.