Air conditioner having multiple outdoor units, and control method thereof

Abstract

The present invention discloses an air conditioner having multiple outdoor units, including a plurality of outdoor units disposed outdoors, at least one indoor unit connected to the plurality of outdoor units through refrigerant tubes, for exchanging heat with indoor air, and when part of the outdoor units are operated, a control unit for storing refrigerants in non-operated outdoor units, so that a proper amount of refrigerants can be supplied to the operated outdoor units. The air conditioner having the multiple outdoor units can improve performance and durability by preventing the refrigerants from being excessively concentrated on the operated outdoor units.

1 . An air conditioner having multiple outdoor units, comprising: 
 a plurality of outdoor units disposed outdoors;    at least one indoor unit connected to the plurality of outdoor units through refrigerant tubes, for exchanging heat with indoor air; and    when part of the outdoor units are operated, a control unit for storing refrigerants in non-operated outdoor units, so that a proper amount of refrigerants can be supplied to the operated outdoor units.    
   
   
       2 . The air conditioner of  claim 1 , wherein the outdoor units each respectively comprises: 
 an outdoor heat exchanger for exchanging heat with outdoor air;    a four-way valve for switching a flow of the refrigerants in the forward or backward direction;    compressors for changing the refrigerants into high temperature high pressure by compression; and    a plurality of accumulators for separating the refrigerants supplied to the compressors into gas and liquid.    
   
   
       3 . The air conditioner of  claim 1 , wherein first valves for opening or closing discharge tubes of the outdoor units are mounted on the discharge tubes, and second valves for opening or closing suction tubes of the outdoor units are mounted on the suction tubes.  
   
   
       4 . The air conditioner of  claim 3 , wherein the first and second valves are solenoid valves operated when power is applied thereto.  
   
   
       5 . The air conditioner of  claim 3 , wherein the control unit comprises: 
 a sensing unit for sensing an amount of refrigerants supplied to the operated outdoor units; and    a controller for compressing and storing the refrigerants in the non-operated outdoor units, by controlling the first open/close valves and the second open/close valves installed at the suction and discharge tubes of the non-operated outdoor units according to the signal from the sensing unit.    
   
   
       6 . The air conditioner of  claim 5 , wherein the control unit further comprises a load sensor for sensing load of the indoor unit.  
   
   
       7 . The air conditioner of  claim 5 , wherein the sensing unit comprises: 
 a first pressure sensor installed at the refrigerant tubes for discharging the refrigerants from the compressors, for sensing a pressure of the refrigerants passing through the compressors; and    a second pressure sensor installed at the refrigerant tubes for sucking the refrigerants into the compressors, for sensing a pressure of the refrigerants supplied to the compressors.    
   
   
       8 . A control method of an air conditioner having multiple outdoor units, comprising: 
 in a partial load operation in which part of the outdoor units are operated, a first step for measuring an amount of refrigerants supplied to the operated outdoor units;    when the amount of the refrigerants supplied to the operated outdoor units exceeds a set amount in the first step, a second step for compressing and storing the refrigerants in non-operated outdoor units, by closing discharge tubes of the non-operated outdoor units; and    when the refrigerants are compressed and stored in the non-operated outdoor units and the amount of the refrigerants supplied to the operated outdoor units reaches the set amount in the second step, a third step for closing suction tubes of the non-operated outdoor units.    
   
   
       9 . The method of  claim 8 , wherein the first step comprises the sub-steps of: 
 sensing load of an indoor unit;    when the indoor unit has a partial load state, driving part of the outdoor units; and    sensing refrigerant pressures in the operated outdoor units.    
   
   
       10 . The method of  claim 9 , wherein the step for sensing the refrigerant pressures senses the pressure of the refrigerants supplied to the compressors of the operated outdoor units in the low pressure sides and the pressure of the refrigerants compressed in the compressors in the high pressure sides, respectively.  
   
   
       11 . The method of  claim 8 , wherein the second step comprises the sub-steps of: 
 comparing refrigerant pressures in the high and low pressure sides of the operated outdoor units with a set pressure;    when the refrigerant pressures of the operated outdoor units are higher than the set pressure, converting the non-operated outdoor units into a cooling mode; and    storing the refrigerants sucked into the non-operated outdoor units in the non-operated outdoor units, by preventing discharge of the refrigerants by closing the discharge tubes of the non-operated outdoor units.    
   
   
       12 . The method of  claim 11 , wherein first valves are installed at the discharge tubes, for closing the discharge tubes according to the signal from the controller.  
   
   
       13 . The method of  claim 8 , wherein the third step comprises the sub-steps of: 
 deciding whether the refrigerant pressures in the high and low pressure sides of the operated outdoor units reach the set pressure; and    when the refrigerant pressures of the operated outdoor units reach the set pressure, compressing and storing the refrigerants in the non-operated outdoor units, by blocking suction lines of the non-operated outdoor units.    
   
   
       14 . The method of  claim 13 , wherein second valves are installed at the suction lines of the non-operated outdoor units, for blocking the suction lines according to the signal from the controller.