Fujitsu General Limited

Yasuhiro Oka

Takahiro Matsunaga

Kotaro Toya

Hideya Tamura

Shinju Watanabe

Ken Nakashima

Takashi Kimura

Keito Kawai

Makoto Shimotani

Toshihiro Takahashi

Satoshi Tomioka

Koji Ogata

Masaki Arai

Shigeaki Suyama

Masakazu Sato

An air conditioner includes: an outdoor unit; a plurality of indoor units respectively including indoor heat exchangers; expansion valves respectively provided to the plurality of indoor units, the expansion valves being configured to adjust flow rates of a refrigerant in the indoor heat exchangers; and a controller for executing a refrigerant amount balance control for adjusting opening degrees of the expansion valves so that operation state amounts, with which the indoor heat exchangers exert heat exchange amounts, of the plurality of indoor units become equal to each other.

Air conditioner

When a refrigerant amount balance control is executed, in indoor units where the refrigerant supercooling degree is lower than an average refrigerant supercooling degree, the refrigerant pressure on a downstream side of indoor expansion valves decreases since the degrees of opening of the valves are decreased. On the other hand, in an indoor unit where the refrigerant supercooling degree is higher than the average refrigerant supercooling degree, although the degrees of opening of the valves are made high, the refrigerant pressure on the downstream side of the valves decreases and this decreases the refrigerant pressure on the downstream side of the indoor expansion valve, so that the difference in pressure between on the upstream side and on the downstream side of the indoor expansion valve increases and the liquid refrigerant staying at an indoor heat exchanger of the indoor unit consequently flows out into a liquid pipe.

An air conditionerof the embodiment of the present invention, when all compressors-have been stopping for a given time or more, starts an air conditioning operation without performing pressure equalizing control in switch units-with starting the operation of the air conditioner. Also, when the stopping time of all compressors-is less than the given time, the air conditionerperforms the pressure equalizing control by controlling switch units-with starting the operation of the air conditioner. In this case, when the stopping time reaches the given time during execution of the pressure equalizing processing control, the pressure equalizing processing control being executed is stopped and the air conditioning operation is started.

An outdoor unit of an air conditioner coupled to an indoor unit by a liquid pipe and a gas pipe, includes: a compressor; an outdoor heat exchanger; a discharge pipe coupled to a refrigerant discharge side of the compressor; an intake pipe coupled to a refrigerant intake side of the compressor; an outdoor-unit high-pressure gas pipe coupled to the discharge pipe; an outdoor-unit low-pressure gas pipe coupled to the intake pipe; an outdoor-unit liquid pipe that couples a first refrigerant entry/exit opening of the outdoor heat exchanger and the liquid pipe together; a bypass pipe coupled to the outdoor-unit liquid pipe; a first flow-passage switcher coupled to a second refrigerant entry/exit opening of the outdoor heat exchanger, the discharge pipe, the intake pipe, and the bypass pipe; and a second flow-passage switcher coupled to the gas pipe, the outdoor-unit high-pressure gas pipe, and the outdoor-unit low-pressure gas pipe.

Outdoor unit of air conditioner and air conditioner

A CPUcompares the extracted outside air temperature with a first low pressure saturation temperature. When the outside air temperature is lower than the first low pressure saturation temperature, the CPUswitches a first three-way valveand a second three-way valveso that a second outdoor heat exchangeris used as a condenser and that a first outdoor heat exchangeris not used. When the outside air temperature is higher than a second low pressure saturation temperature which is the first low pressure saturation temperature to which a predetermined temperature is added, the CPUswitches the first three-way valveand the second three-way valveso that the first outdoor heat exchangeris used as a condenser and that the second outdoor heat exchangeris not used.

Air conditioning apparatus

When the temperatures of outdoor heat exchangersanddetected by outdoor heat exchanger temperature sensorsandbecome equal to or higher than 5 degrees C. and the sucking superheating degrees of compressorsandbecome equal to or lower than 0 degrees C. while an air conditioning apparatusis performing the reverse defrosting operation, the reverse defrosting operation is stopped and the heating dominant operation is resumed. At this time, the total operating times of the compressorsandare reset. The sucking superheating degrees of the compressorsandare obtained by subtracting the low pressure saturation temperatures calculated from the sucking pressures of the compressorsand, from the temperatures of the refrigerants sucked into the compressorsandwhich temperatures are detected by the sucking temperature sensorsand

An outdoor unit for an air-conditioning apparatus includes an outdoor heat exchanger; a compressor; a refrigerant pipe configured to couple the outdoor heat exchanger and the compressor with an indoor unit including an indoor heat exchanger; and a control unit that determines whether the heating capacity of the indoor unit performing a heating operation is decreased by the refrigerant stagnated in the indoor heat exchanger.

Outdoor unit for air-conditioning apparatus, and air-conditioning apparatus

An outdoor unit for an air-conditioning apparatus includes: a compressor; an outdoor fan; a plurality of outdoor heat exchangers coupled to a plurality of indoor units; a switching member configured to switch functions of the outdoor heat exchangers to either condensers or evaporators by switching of coupling states between the compressor and the outdoor heat exchangers; and a control unit configured to calculate a low pressure saturation temperature during a cooling operation or a cooling-main operation, and configured to cause all of the plurality of outdoor heat exchangers to serve as condensers by controlling the switching member when a state in which an open-air temperature is lower than the low pressure saturation temperature continues for a predetermined time.

An air conditioning apparatusincludes first start control and second start control as its start control. In the first start control, first outdoor heat exchangersare controlled to function as evaporators and second outdoor heat exchangersare controlled to function as condensers. Thus, even when the compressorsare driven on at a given rotation number, the discharge pressures thereof can be prevented from increasing, thereby being able to prevent the internal pressures of the compressorsfrom increasing. Also, after end of the first start control, the first outdoor heat exchangers, 24and second outdoor heat exchangersare all controlled to function as evaporators, and the compressorsare driven on at a given rotation number. This can shorten the rising time of the heating capacity in the start of the normal heating operation.

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Kawasaki, Japan

Yasuhiro Oka