Hitachi, Ltd.

Hitachi Shimizu Engineering Co., Ltd.

Hitachi Shimizu

Satoru Yoshida

Takashi Kato

Masashi Watanabe

Masamichi Mochizuki

Keiji Sato

Susumu Nakayama

Hiroshi Takenaka

Yasutaka Yoshida

Koji Naito

An air conditioner comprising a refrigerant forward path branching on a discharge side of a compressor in an outdoor unit, one of the branched portions being defined by connecting a first four-way valve, a first outdoor heat exchanger and a first outdoor expansion valve to one another in this order, and the other of the branched portions being defined by connecting a second four-way valve, a second outdoor heat exchanger and a second outdoor expansion valve in this order, the path extending to an indoor unit from the respective outdoor expansion valves through a liquid-side piping, and returning to the outdoor unit from the indoor unit through a gas-side piping to branch, one of the branched portions being connected to the first four-way valve via a check valve placed in communication in a forward direction and the other of the branched portions being connected to the second four-way valve, the air conditioner being controlled such that, when heating operation is switched to defrosting operation, the second four-way valve is switched if a pressure difference between discharge pressure and suction pressure of the compressor is equal to or above a predetermined value, and the first four-way valve is switched after a gas-side pressure of the second outdoor heat exchanger has risen, whereby the four-way valves are prevented from being made inoperative due to short-circuit between high pressure side and low pressure side.

Air conditioner

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.

Multiple type air conditioner system and address setting method thereof

A system for sending programs for controlling an air conditioner, comprising at least one indoor unit and an outdoor unit connected to the indoor unit, the outdoor unit including a first memory for storing a program for controlling the room condition, a second memory for storing a program for controlling the outdoor unit in cooperation with the room condition control program, and a communication circuit for sending contents of the program in the memory to the indoor unit, the indoor unit including a third memory for storing a receiving execution program for executing the receiving of the room condition control program from the outdoor unit, a communication circuit for receiving the program from the outdoor unit, and a fourth memory for storing the program received. The third memory has stored therein the receiving program at an address at which the execution thereof is started when power is turned on. The control programs may be sent from the central control unit to the outdoor unit connected thereto and also to the indoor unit connected to the outdoor unit to implement control.

System and method for controlling air conditioner

Growing community of inventors

Shimizu, Japan

Satoru Yoshida