To optimize the operation of air conditioning systems

the extremum entransy increase principle is proposed

and an entransy loss model for each component and entransy increase model for the whole system are established for air conditioning systems based on entransy theory. The entransy increase rate of the air conditioning system under different operation conditions is experimentally studied when the system cooling load and total power consumption are fixed separately. The results prove that the extremum entransy increase principle holds and determine the optimal operation conditions. When the system cooling load is 5 kW

the optimal compressor frequency is 70 Hz

optimal chilled water flow rate is 0.6 kg/s

and optimal cooling water flow rate is 0.9 kg/s. These parameter values produce the minimum system entransy increase rate

minimum power consumption rate

and maximum system efficiency. When the system power consumption is 2.8 kW

the optimal compressor frequency

chilled water flow rate

and cooling water flow rate are 97.9 Hz

0.41 kg/s

and 1.00 kg/s

leading to the maximum system entransy increase rate

maximum system cooling load

and maximum system efficiency.