Hitachi, Ltd.

Toshiyuki Hojo

Kensaku Oguni

Kenji Tokusa

Susumu Nakayama

Fumio Harada

Keij Tanaka

Tadayuki Urushihata

Disclosed is a multi-airconditioner including a plurality of outdoor units and at least one indoor units in which refrigerant conduits connecting the outdoor units and the at least one indoor units are united in the form of two or three conduits. In the case of the multi-airconditioner for effecting either room-cooling or room-heating, each of the outdoor units and each of the indoor units have a liquefied refrigerant conduit and a gasified refrigerant conduit, which are connected with a single common liquefied refrigerant conduit and a single common gasified refrigerant conduit, respectively. In the case of the multi-conditioner for effecting simultaneous room-cooling and room-heating operation in which some of the indoor units are under room-cooling operation while the other indoor units are under room-heating operation, each outdoor unit and each indoor unit have a liquefied refrigerant conduit, a high-pressure gasified refrigerant conduit and a low-pressure gasified refrigerant conduit, and these liquefied refrigerant conduits, high-pressure gasified refrigerant conduits and low-pressure gasified refrigerant conduits are connected to a single common liquefied refrigerant conduit, a single common high-pressure gasified refrigerant conduit and a single common low-pressure gasified refrigerant conduit, respectively.

Multi-airconditioner

An air-conditioning system for a cooling operation and a heating operation comprises a first heat exchanger to which a high-pressure and high-temperature refrigerant which has not been substantially cooled and adiabatically expanded after being compressed is supplied to heat the inside of a room to be air-conditioned during both of the cooling operation and the heating operation, a second heat exchanger to which a low-pressure and low-temperature refrigerant which has been substantially cooled and adiabatically expanded after being compressed is supplied to cool the inside of the room during both of the cooling operation and heating operation, and an air flow generator for generating an air flow which passes the first heat exchanger and the second heat exchanger, wherein the second heat exchanger is arranged at an upstream side of the first heat exchanger in the air flow.

Air conditioning system

A method for controlling a refrigerant path apparatus including a pressurized gas refrigerant path for a flow of a pressurized gas refrigerant which has not been substantially cooled to be liquefied, a pressurized liquid refrigerant path for a flow of a pressurized liquid refrigerant which is generated from the pressurized gas refrigerant by being cooled to be liquefied, a first heat exchanger means which is fluidly connected to the pressurized gas refrigerant path to supply the pressurized gas refrigerant into the first heat exchanger so that a heat exchange is carried out between the pressurized gas refrigerant in the first heat exchanger and the outside of the first heat exchanger, comprises the steps of allowing a flow of the refrigerant from the pressurized gas refrigerant path to the pressurized liquid refrigerant path when a supply of the pressurized gas refrigerant from the pressurized gas refrigerant path into the first heat exchanger means is prevented, and preventing the flow of the refrigerant from the pressurized gas refrigerant path to the pressurized liquid refrigerant path when the supply of the pressurized gas refrigerant form the pressurized gas refrigerant path into the first heat exchanger means is allowed.

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Shimizu, Japan

Toshiyuki Hojo