Fujitsu General Limited

Keito Kawai

Takahiro Matsunaga

Hideya Tamura

Kotaro Toya

Yasuhiro Oka

Shinju Watanabe

Ken Nakashima

Takashi Kimura

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.

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: 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.

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

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

Keito Kawai