Air conditioner and method of controlling the same

Abstract

An air conditioner includes first and second compressors, an outdoor heat exchanger through which refrigerant discharged from the first and second compressors passes, an outdoor fan for forcedly directing air toward the outdoor heat exchanger, an expansion valve for expanding the refrigerant discharged from the outdoor heat exchanger, an indoor heat exchanger through which the refrigerant expanded in the expansion valve passes, a linear expansion valve for adjust a flow rate of the refrigerant, a load detecting unit for deterring an indoor load, and a control unit for controlling the operation of the first and second compressors in accordance with the detected indoor load. In a state where the second compressor is not driven, the control unit allows the second compressor to drive when a driving start conditioner of the second compressor is satisfied and a driving start retarding time has been elapsed. The control unit adjusts an opening of the linear expansion valve and an operation of the outdoor fan for the driving start retarding time.

1 . A method of controlling an air conditioner, comprising: 
 driving a first compressor among a plurality of compressors;    determining if a driving start condition of the second compressor is satisfied during driving of the first compressor; and    adjusting, when the driving start condition of the second compressor is satisfied, at least one of discharge and intake pressures of the second compressor for a driving start retarding time such that a difference between the discharge and intake pressures is less than a predetermined value.    
   
   
       2 . The method according to  claim 1 , wherein one of the first and second compressors is an inverter compressor and the other is a constant compressor.  
   
   
       3 . The method according to  claim 1 , wherein the driving start retarding time is a time measured after only the first compressor is driven.  
   
   
       4 . The method according to  claim 1 , wherein the discharge pressure of the second compressor is reduced for the driving start retarding time of the second compressor.  
   
   
       5 . The method according to  claim 4 , wherein a linear expansion valve is fully opened for a first reference time to reduce the discharge pressure of the second compressor.  
   
   
       6 . The method according to  claim 5 , wherein the opening of the linear expansion valve is returned to an initial state when the first reference time has been elapsed.  
   
   
       7 . The method according to  claim 1 , wherein the intake pressure increases for the driving start retarding time of the second compressor.  
   
   
       8 . The method according to  claim 7 , wherein an outdoor fan is stopped for a second reference time in order to increase the intake pressure of the second compressor.  
   
   
       9 . The method according to  claim 8 , wherein the outdoor fan starts operating after the second reference time has been elapsed.  
   
   
       10 . The method according to  claim 1 , wherein the discharge pressure of the second compressor is reduced for the driving start retarding time while the intake pressure of the second compressor increases for the driving start retarding time.  
   
   
       11 . The method according to  claim 10 , wherein the reduction of the discharge pressure and the increase of the intake pressure are sequentially realized.  
   
   
       12 . The method according to  claim 11 , wherein a linear expansion valve for adjusting a flow rate of the refrigerant is fully opened for a first reference time to reduce the discharge pressure of the second compressor and an outdoor fan is stopped for a second reference time in order to increase the intake pressure of the second compressor.  
   
   
       13 . The air conditioner according to  claim 12 , further comprising driving the second compressor after the driving start retarding time has been elapsed.  
   
   
       14 . A method of controlling an air conditioner, comprising: 
 stopping driving of a first compressor during driving of a plurality of compressors;    determining if a driving start condition of the first compressor is satisfied; and    driving, when the driving start condition is satisfied, the first compressor after a driving start retarding condition has been elapsed,    wherein a discharge pressure of the first compressor is forcedly reduced for the driving start retarding time or an intake pressure of the first compressor is forcedly increased for the driving start retarding time.    
   
   
       15 . The method of  claim 14 , wherein a linear expansion valve for adjusting a flow rate of the refrigerant is fully opened for a first reference time to reduce the discharge pressure of the second compressor.  
   
   
       16 . The method according to  claim 15 , wherein the opening of the linear expansion valve is returned to an initial state when the first reference time has been elapsed.  
   
   
       17 . The method according to  claim 16 , wherein driving of an outdoor fan is stopped for a second reference time after the opening of the linear expansion valve is returned to the initial state.  
   
   
       18 . The method according to  claim 17 , wherein the outdoor fan starts driving after the second reference time has been elapsed.  
   
   
       19 . An air conditioner comprising: 
 first and second compressors;    an outdoor heat exchanger through which refrigerant discharged from the first and second compressors passes;    an outdoor fan for forcedly directing air toward the outdoor heat exchanger;    an expansion valve for expanding the refrigerant discharged from the outdoor heat exchanger;    an indoor heat exchanger through which the refrigerant expanded in the expansion valve passes;    a linear expansion valve for adjust a flow rate of the refrigerant;    a load detecting unit for deterring an indoor load; and    a control unit for controlling the operation of the first and second compressors in accordance with the detected indoor load,    wherein, in a state where the second compressor is not driven, the control unit allows the second compressor to drive when a driving start conditioner of the second compressor is satisfied and a driving start retarding time has been elapsed; and    the control unit adjusts an opening of the linear expansion valve or an operation of the outdoor fan for the driving start retarding time.    
   
   
       20 . The air conditioner according to  claim 19 , wherein the linear expansion valve is fully opened for a first reference time within a range of the driving start retarding time and the outdoor fan is stopped for a second reference time within a range of the driving start retarding time.