Air conditioner and method for operating same

Abstract

An air conditioner according to the present comprises a plurality of chillers which include a compressor, a condenser, a expansion device and an evaporator and supply cold water through water pipes connected to the evaporator in parallel. An operating chiller of the plurality of chillers sets a cold water set temperature of the operating chiller according to pressure difference between high pressure part and low pressure part and controls the compressor capacity according to the cold water set temperature and transmits an operation order to a chiller not operating until the present if the pressure difference is more than the set pressure for the set time and at least one of the chillers is not operating. Thus, it is possible to perform an efficient operation according to load and to minimized power consumption.

1 . An air conditioner comprising:
 a plurality of chillers which include a compressor, a condenser, an expansion device and an evaporator and supply cold water through water pipes connected to the evaporator in parallel,   wherein an operating chiller of the plurality of chillers sets a cold water set temperature of the operating chiller according to pressure difference between high pressure part and low pressure part and controls the compressor capacity according to the cold water set temperature and transmits an operation order to a chiller not operating until the present if the pressure difference is more than the set pressure for the set time and at least one of the chillers is not operating.   
     
     
         2 . The air conditioner of  claim 1 ,
 wherein each of the chillers comprises a low pressure sensor for sensing suction pressure of the compressor; and   a high pressure sensor for sensing discharge pressure of the compressor; and   a chiller controller for setting a cold-water set temperature according to the pressure difference between the high pressure sensed by the high-pressure sensor and the low-pressure sensed by the low-pressure sensor, and for controlling the compressor capacity according to the cold water set temperature.   
     
     
         3 . The air conditioner of  claim 2 ,
 further comprising a common water pipe temperature sensor for sensing temperature of a common water pipe which coolant supplied from the plurality of the chillers passes through together,   wherein the chiller controller sets a cold-water set temperature according to the temperature sensed by the common water pipe temperature sensor.   
     
     
         4 . The air conditioner of  claim 2 ,
 further comprising a communication line, which is connected to each the chiller controllers of the chillers for transmitting an operation order from one of the chillers to the other.   
     
     
         5 . An operation method of an air conditioner which comprises
 a compressor,   a condenser,   an expansion device and   an evaporator and supplies cold water through the water pipes connected to the evaporator and operates a plurality of chillers connected the water pipes in parallel, wherein the operation method comprises steps of;
 setting a cold water set temperature if the pressure difference between the high pressure part and the low pressure part of the operating chiller is more than the set pressure for the set time; and 
 controlling compressor capacity according to the cold water set temperature set at the step of setting a cold water set temperature; and 
 transmitting an operation order to the non-operating chiller if the pressure difference is more than the set pressure for set time and at least one of the chillers is not operating until the present. 
   
     
     
         6 . The operation method of an air conditioner of  claim 5 ,
 wherein, in the step of setting the cold water set temperature, if the pressure difference is more than the set pressure for the set time, the cold water set temperature is raised.   
     
     
         7 . The operation method of an air conditioner of  claim 5 ,
 wherein, in the step of transmitting the operation order, the operation order and the stop set temperature of the chiller not operating until the present are transmitted together to the non-operating chiller.   
     
     
         8 . The operation method of an air conditioner of  claim 5 , wherein, after the step of transmitting the operation order, if the cold-water exit temperature of a common water pipe of all water pipes is different with the water set temperature, it returns to the step of setting the cold water set temperature. 
     
     
         9 . The operation method of an air conditioner of  claim 5 , further comprising steps of;
 increasing the cold water set temperature if the cold water exit temperature of a common water pip of all the water pipes is lower than the cold water set temperature after the step of transmitting the operation order; and   re-controlling the capacity of the compressor according to the cold water set temperature set in the step of increasing the cold water set temperature.   
     
     
         10 . The operation method of an air conditioner of  claim 9 , further comprising a step of;
 stopping the operating chiller if the cold water set temperature is higher than the stop set temperature of the chiller after the step of re-controlling the compressor capacity.   
     
     
         11 . The operation method of an air conditioner of  claim 10 , further comprising steps of;
 decreasing the cold water set temperature if the cold water exit temperature of a common water pipe of all the water pipes is higher than the cold water temperature after the step of transmitting the operation order; and   re-controlling the compressor capacity according to the cold water set temperature set in the step of decreasing the cold water set temperature.   
     
     
         12 . The operation method of an air conditioner of  claim 11 , wherein, after the step of re-controlling the compressor capacity, it returns to the step of setting the cold water set temperature. 
     
     
         13 . The air conditioner of  claim 3 , further comprising a communication line, which is connected to each the chiller controllers of the chillers for transmitting an operation order from one of the chillers to the other.