Fujitsu General Limited

Shintaro Sanada

Yu Hirosaki

Satoshi Tomioka

Takahiro Matsunaga

Hideya Tamura

Tetsuya Ito

Takamitsu Kurokawa

Koya Aoki

Tatsuro Yamazaki

Ryo Takaoka

Shunji Itakura

Naruhiro Sekine

Tokihiko Ando

An outdoor unit control unit includes a degree-of-dryness calculating unit that calculates the degree of dryness of a refrigerant flowing into an heat exchanger (an indoor heat exchanger at the time of a cooling operation, and an outdoor heat exchanger at the time of a heating operation) disposed on the downstream side of a liquid pipe, and performs an inhibition mode of inhibiting, when the degree of dryness exceeds a threshold A, control that is performed in the direction of decreasing the degree of opening of the expansion valve (an indoor expansion valve at the time of the cooling operation, and an outdoor expansion valve at the time of the heating operation) disposed on the upstream side of the liquid pipe.

Air conditioning apparatus

An air conditioner includes an outdoor unit, a plurality of indoor units, a plurality of expansion valves which are provided upstream of indoor heat exchangers, a plurality of on-off valves which are provided upstream of the expansion valves, and control unit wherein when the indoor units include a stopping indoor unit and an operating indoor unit currently operating, and when a stopping of the stopping unit is due to thermostat-off operation, the control unit performs a procedure to stop the stopping unit, the procedure including closing an on-off valve that corresponds to the stopping unit and driving an indoor fan in the stopping unit until pressure in a part between the on-off valve and an expansion valve that corresponds to the stopping unit and pressure in a part downstream of the first expansion valve are equalized, fully opening the expansion valve, and stopping the indoor fan.

Air conditioner

The amount of refrigerant to be charged in a refrigerant circuit of an air conditioner is set to a range defined by a lower-limit charge amount and an upper-limit charge amount. The lower-limit charge amount is a charge amount with which a refrigerant supercooling degree is 0 deg and a refrigerant quality is 0 at a refrigerant outlet side of a supercooling heat exchanger when a cooling operation is performed under an overload condition in which the refrigerant is hardly condensed in an outdoor heat exchanger that functions as a condenser. On the other hand, the upper-limit charge amount is a charge amount with which a refrigerant supercooling degree is 0 deg and a refrigerant quality is 0 at a refrigerant outlet side of the outdoor heat exchanger when the cooling operation is performed under a rated condition.

There is provided a refrigeration apparatus in which a refrigerant accumulating in non-operating outdoor units is supplied to an outdoor unit being operated in which a shortage of refrigerant occurs without starting the compressors of the non-operating outdoor units. In the control method for the refrigeration apparatus in which to refrigerant pipinginstalled between the indoor side and the outdoor side, a plurality of outdoor unitsA,B each including a compressor, a directional control valve, an outdoor heat exchanger, an outdoor expansion valve, and an accumulatorare connected in parallel on the outdoor side, and each of the outdoor units is provided with a hot gas bypass circuitthat includes a solenoid valveand an expansion mechanismarranged in series, and is connected between high-pressure side pipingon the discharge side of the compressor and low-pressure side pipingon the accumulator side, if a shortage of refrigerant occurs when air cooling operation is performed in a state in which only the outdoor unitA is operated and other outdoor unitsB are not operated, the solenoid valvesof the non-operating outdoor unitsB are opened so that the refrigerant accumulating in the non-operating outdoor unitsB is supplied to the outdoor unitA via the hot gas bypass circuitand the low-pressure piping

Refrigeration apparatus

A refrigeration apparatus includes an outdoor unit having a first compressor and a second compressor connected in parallel with each other, a first oil separator attached to the first compressor and connected to a suction pipe of the second compressor via a first oil return piping including a pressure reducing device, and a second oil separator attached to the second compressor and connected to a suction pipe of the first compressor via a second oil return piping including a pressure reducing device. The suction pipes of the first and second compressors are connected together. The first compressor is a variable-speed compressor, and the second compressor is a constant-speed compressor. A solenoid valve selectively forming a bypass circuit with respect to the pressure reducing device, is connected in parallel with the pressure reducing device of the first oil return piping. The solenoid valve is opened when the first compressor is restarted.

Growing community of inventors

Kawasaki, Japan

Shintaro Sanada