PURPOSE: To effect the optimum operation, improve the efficiency of an air- conditioning machine and prevent shortage of capacity of the indoor machine of a higher order when there is the difference in height in indoor machines by a method wherein the rate of composition of circulating refrigerant is estimated by the height of liquid level in an accumulator, the saturating temperature of liquid is operated with a good accuracy, the operating accuracy of the degree of supercooling at the outlet port of an indoor machine side heat exchanger is improved and the opening degree of an indoor side expansion valve is controlled so as to be the optimum degree of opening.
CONSTITUTION: An air-conditioning machine is provided with a liquid level height detecting sensor 18, detecting the height of liquid level in an accumulator 6, a circulating refrigerant rate of composition estimating device 19, estimating the rate of composition of circulating refrigerant, a high-pressure side pressure sensor 12, detecting a high-pressure side pressure, liquid pipeline temperature detecting sensors 13a-13c, detecting liquid pipeline temperatures, supercooling degree operating means 25a-25c, operating the supercooling degree of the outlet port of indoor side heat exchangers, and refrigerant control means 17a-17c, controlling the opening degree of indoor side expansion valves.
KURACHI MASAO
KITAYAMA HIROSHI
MARUMOTO KAZUHIKO
