Abstract: In a multiple type air conditioner system which includes a plurality of outdoor units and a plurality of indoor units, the plurality of outdoor units are connected with the plurality of indoor units through a communication line, address setting is attained by generating a random address from each of all the indoor units under a command of one of the outdoor units and generating a dummy address from each outdoor unit on the basis of the random address, by obtaining a correlative relationship between the outdoor and indoor units on the basis of a variation of a physical quantity of the outdoor unit connected to the indoor unit actually operated based on the dummy address, and by updating the addresses of all the outdoor and indoor units on the basis of the correlative relationships between all the outdoor and indoor units obtained through the step.

Abstract: An air conditioning control system ensuring the desired full utility so that the operation of a plurality of air conditioners installed in a building can be controlled and monitored at a plurality of spots in the building. The air conditioning control system includes a building's central monitor board controlling and monitoring the operation of the individual air conditioners, and a centralized control unit relaying air conditioner control information outputted from the central monitor board and information indicating the operation status of the individual air conditioners, each of the central monitor board and the centralized control unit including an input part inputting the control information to the individual air conditioners and a display part displaying the operation status information regarding the individual air conditioners.

Abstract: An overheating prevention method for a fixed displacement type compressor having an overheating prevention device for introducing a part of high pressure liquefied coolant, liquefied in a compressor of a refrigeration cycle, into a compression chamber maintained under a compression stroke of the compressor through a connecting pipe, and for controlling a flow rate of the liquefied coolant flowing through the communication pipe to thereby cool the compressor. The connecting pipe is communicated with the compressor so that an average pressure within the compressor is reduced relative to a condensed pressure under a minimum operational pressure ratio condition at which the introduction of the liquefied coolant is required for cooling the compressor, within an operational pressure range in which the condensed pressure and evaporation pressure are respectively variable.

Abstract: A refrigeration cycle apparatus wherein a positive displacement type compressor is used as a cooling medium compressor, and part of a high-pressure liquid cooling medium liquefied in a condenser of a refrigeration cycle is introduced into a compression chamber of the compressor during a compression stroke thereof via first and second connecting pipes connected to the compressor, thereby preventing the overheating of the compressor. The position of connection of the first connecting pipe to the compressor is set to such a position of the compression chamber that when an operating pressure ratio requiring the cooling of the compressor is minimum, the pressure within the compression chamber of the compressor during the compression stroke can be below a condensation pressure at the operating pressure ratio.

Abstract: An air conditioner provided with a refrigerant circuit formed by connecting with piping a refrigerant compressor, a condenser, an expansion means and an evaporator, an inverter power supply means for controlling the rotational speed of an electric motor for driving the refrigerant compressor, a load detector, and a controller for controlling the inverter power supply means on the basis of an output from the load detector. A refrigerant flow passage controlling mechanism is provided to change the rate at which the refrigerant flows through the condenser on the basis of a control command from the controller, thereby making it possible to reduce or increase the discharge rate without extending the range of changes in the rotational speed of the compressor. The compressor can be controlled according to a wide range of changes in the load to operate with an operation range which ensures high efficiency of the compressor operation.