Multi-air conditioner capable of performing simultaneous cooling and heating

Abstract

A multi-air conditioner capable of simultaneous cooling and heating, includes: a first duct connected to a discharge side of a compressor, through which a refrigerant discharged from the compressor passes at the time of cooling operation; a second duct diverged from the first duct, through which a refrigerant discharged from the compressor passes at the time of heating operation; and an oil accumulation preventing portion formed at a certain section of the second duct to have a height difference, for preventing oil, which is introduced to the second duct from the compressor together with a refrigerant, from being accumulated in the second duct. Accordingly, the multi-air conditioner capable of simultaneous cooling and heating can prevent damage to the compressor due to a shortage of oil and thusly improve reliability of a compressor by preventing oil accumulation within a duct.

1 . A multi-air conditioner capable of simultaneous cooling and heating, comprising: 
 a first duct connected to a discharge side of a compressor, through which a refrigerant discharged from the compressor passes at the- time of cooling operation;    a second duct diverged from the first duct, through which a refrigerant discharged from the compressor passes at the time of heating operation; and    an oil accumulation preventing portion formed at a certain section of the second duct to have a height difference, for preventing oil, which is introduced to the second duct from the compressor together with a refrigerant, from being accumulated within the second duct.    
   
   
       2 . The multi-air conditioner of  claim 1 , wherein the oil accumulation preventing portion is placed in the vicinity of an inlet portion of the second duct.  
   
   
       3 . The multi-air conditioner of  claim 1 , wherein a section between an inlet portion of the second duct and a starting point of the oil accumulation preventing portion has the same height at both ends.  
   
   
       4 . The multi-air conditioner of  claim 1 , wherein the section between an inlet portion of the second duct and a starting point of the oil accumulation preventing portion is inclined at a predetermined angle such that its height is lowered toward the inlet portion of the second duct.  
   
   
       5 . The multi-air conditioner of  claim 3 , wherein the section between the inlet portion of the section duct and the starting point of the oil accumulation preventing portion is formed as a straight line.  
   
   
       6 . The multi-air conditioner of  claim 4 , wherein the section between the inlet portion of the section duct and the starting point of the oil accumulation preventing portion is formed as a straight line.  
   
   
       7 . The multi-air conditioner of  claim 1 , wherein the oil accumulation preventing portion includes a highest spot and a downward section continued from the highest spot.  
   
   
       8 . The multi-air conditioner of  claim 1 , wherein a height from the starting point of the oil accumulation preventing portion to the highest spot of the oil accumulation portion is the same as or greater than a diameter of the second duct.  
   
   
       9 . The multi-air conditioner of  claim 1 , wherein the oil accumulation preventing portion includes at least one curved section.  
   
   
       10 . The multi-air conditioner of  claim 1 , wherein the oil accumulation preventing portion is formed as a reverse trap structure.  
   
   
       11 . The multi-air conditioner of  claim 1 , wherein the oil accumulation preventing portion is formed such that a starting point of the oil accumulation preventing portion coincides with an inlet portion of the second duct.  
   
   
       12 . A multi-air conditioner capable of simultaneous cooling and heating, comprising:. 
 an outdoor unit having therein a compressor and an outdoor heat exchanger;    a plurality of indoor units, each having therein an electronic expansion valve and an indoor heat exchanger;    a distributor provided between the outdoor unit and the indoor unit and distributing a refrigerant introduced from the outdoor unit to the plurality of indoor units;    a duct unit including a first duct connecting the distributor to a discharge side of the compressor, having the outdoor heat exchanger in the middle and guiding a refrigerant discharged from the compressor toward the indoor heat exchanger, and a second duct diverged from the first duct, connected to the distributor and guiding a refrigerant discharged from the compressor toward the indoor heat exchanger; and    an oil accumulation portion formed to have a height difference at a certain section of the second duct in order to prevent oil, which is introduced to the second duct from the compressor together with a refrigerant, from being accumulated within the second duct.    
   
   
       13 . The multi-air conditioner of  claim 12 , wherein the oil accumulation preventing portion is placed in the vicinity of an inlet portion of the second duct.  
   
   
       14 . The multi-air conditioner of  claim 12 , wherein a section between an inlet portion of the second duct and a starting point of the oil accumulation preventing portion has the same height at both ends.  
   
   
       15 . The multi-air conditioner of  claim 12 , wherein a section between an inlet portion of the second duct and a starting point of the oil accumulation preventing portion is inclined at a predetermined angle such that its height is lowered toward the inlet portion of the second duct.  
   
   
       16 . The multi-air conditioner of  claim 14 , wherein a section between an inlet portion of the second duct and a starting point of the oil accumulation preventing portion is formed as a straight line.  
   
   
       17 . The multi-air conditioner of  claim 15 , wherein a section between an inlet portion of the second duct and a starting point of the oil accumulation preventing portion is formed as a straight line.  
   
   
       18 . The multi-air conditioner of  claim 12 , wherein the oil accumulation preventing portion includes a highest spot and a downward section continued from the highest spot.  
   
   
       19 . The multi-air conditioner of  claim 12 , wherein a height from the starting point of the oil accumulation preventing portion to the highest spot of the oil accumulation preventing portion is the same as or greater than a diameter of the second duct.  
   
   
       20 . The multi-air conditioner of  claim 12 , wherein the oil accumulation preventing portion includes at least one curved section.  
   
   
       21 . The multi-air conditioner of  claim 12 , wherein the oil accumulation preventing portion has a reverse trap structure.  
   
   
       22 . The multi-air conditioner of  claim 12 , wherein the oil accumulation preventing portion is formed such that a starting point of the oil accumulation preventing portion coincides with an inlet portion of the second duct.  
   
   
       23 . The multi-air conditioner of  claim 12 , wherein the distributor comprises: 
 a low pressure gaseous refrigerant duct for guiding a low pressure gaseous refrigerant discharged from the plurality of indoor units to the compressor at the time of cooling operation; and    a liquefaction preventing unit provided between the second duct and the low pressure gaseous refrigerant duct and preventing liquefaction of a high pressure gaseous refrigerant accumulated in the second duct at the time of full cooling operation.    
   
   
       24 . The multi-air conditioner of  claim 23 , wherein the liquefaction preventing unit comprises: 
 a bypass duct connecting the low pressure gaseous refrigerant duct with the second duct;    a blocking valve provided on the bypass duct and allowing a refrigerant accumulated in the second duct at the time of full cooling operation to flow to the low pressure gaseous refrigerant duct; and    a capillary duct decompressing and expanding a high pressure gaseous refrigerant accumulated within the second duct and converting the refrigerant into a low pressure gaseous refrigerant.