Method of controlling over-load cooling operation of air conditioner

Abstract

A method of controlling an over-load cooling operation of an air conditioner includes over-load operation mode in which, when an outdoor pipe temperature and an outdoor temperature exceeds reference temperatures, respectively, the operation capacity is changed to a low-level operation capacity, which is lower than the current operation capacity, the low-level operation capacity being one of plural operation capacities set according to the operation capacities of compressors, and the operation is performed, and normal operation mode in which the outdoor pipe temperature is measured every predetermined period of time after the operation is performed in the over-load operation mode, and, when the measured outdoor pipe temperature is below the reference temperature, the operation is performed according to a signal from a thermostat. The continuous cooling operation is possible even under the over-load condition during the cooling operation of the air conditioner, and the air conditioner system is protected through the variable-capacity operation. Consequently, the present invention has the effect of improving user comfort and improving operational reliability of the air conditioner.

1 . A method of controlling an over-load cooling operation of an air conditioner including: 
 an over-load operation mode in which, when an outdoor pipe temperature and an outdoor temperature exceeds reference temperatures, respectively, the operation capacity is changed to a low-level operation capacity, which is lower than the current operation capacity, the low-level operation capacity being one of plural operation capacities set according to the operation capacities of compressors, and the operation is performed; and    a normal operation mode in which the outdoor pipe temperature is measured every predetermined period of time after the operation is performed in the over-load operation mode, and, when the measured outdoor pipe temperature is below the reference temperature, the operation is performed according to a signal from a thermostat.    
   
   
       2 . The method as set forth in  claim 1 , wherein the reference temperature of the outdoor pipe temperature is set to be higher than the reference temperature of the outdoor temperature.  
   
   
       3 . The method as set forth in  claim 1 , wherein 
 at the beginning in the over-load operation mode, the operation capacity is changed to a first low-level operation capacity, which is lower than the current operation capacity, and    if the outdoor pipe temperature or the outdoor temperature exceeds the reference temperatures when a predetermined period of time elapses after the operation is performed in the over-load operation mode, the operation capacity is changed to a second low-level operation capacity, which is lower than the first low-level operation capacity, and then the operation is performed in the second low-level operation capacity.    
   
   
       4 . The method as set forth in  claim 1 , wherein 
 on the assumption that the operation capacities of the compressors are set to X %, Y %, and Z % in order of operation capacities of the compressors in the over-load operation mode,    when the operation capacity is the X % operation capacity, the compressors are operated with the Y % operation capacity, which is lower than the X % operation capacity,    when the operation capacity is the Y % operation capacity, the compressors are operated with the Z % operation capacity, which is lower than the Y % operation capacity, and    when the operation capacity is the Z % operation capacity, the compressors are stopped.    
   
   
       5 . The method as set forth in  claim 1 , wherein 
 when the compressors are operated in the over-load operation mode, an outdoor fan, by which an outdoor heat exchanger is cooled, is operated with high airflow, and    when the compressors are stopped in the over-load operation mode, the outdoor fan is stopped.    
   
   
       6 . The method as set forth in  claim 1 , wherein, if the signal from the thermostat, which controls operation stages of the air conditioner, is changed from a high-level operation. signal to a low-level operation signal during operation in the over-load operation mode, the compressors are returned to the normal operation mode.  
   
   
       7 . The method as set forth in  claim 1 , wherein, if the signal from the thermostat is changed from a low-level operation signal to a high-level operation signal during operation in the over-load operation mode, the operation is still performed in the over-load operation mode.  
   
   
       8 . The method as set forth in  claim 1 , wherein, when the outdoor pipe temperature or the outdoor temperature exceeds the reference temperature after the compressors are returned to the normal operation mode, the operation mode is not changed to the over-load operation mode for a predetermined period of time.  
   
   
       9 . The method as set forth in  claim 1 , wherein, if the outdoor pipe temperature is a specific temperature, which is higher than the reference temperature, when a predetermined period of time elapses after the compressors are started, both the compressors are stopped.  
   
   
       10 . The method as set forth in  claim 9 , wherein, when a predetermined period time elapses after the compressors are stopped, the compressors are restarted in the normal operation mode.