Fujitsu General Limited

Hideya Tamura

Takahiro Matsunaga

Kotaro Toya

Shinju Watanabe

Yasuhiro Oka

Ken Nakashima

Takashi Kimura

Keito Kawai

Satoshi Tomioka

Tetsuya Ito

Shintaro Sanada

Takamitsu Kurokawa

Yuki Watanabe

Toshihiro Takahashi

Yoshiki Tanaka

Koji Ogata

Masaki Arai

Makoto Shimotani

Shinya Asano

Masakazu Sato

There is provided an air conditioner capable of displaying sufficient cooling ability in each indoor unit by allowing a sufficient amount of refrigerant to flow into indoor units where cooling ability cannot be displayed. By executing refrigerant amount balance control, since degrees of opening of indoor expansion valves are narrowed in indoor units whose refrigerant superheating degrees are smaller than an average refrigerant superheating degree, amounts of refrigerant flowing into the indoor expansion valves are decreased. In the indoor unit where the refrigerant superheating degree is higher than the average refrigerant superheating degree, since refrigerant pressure on a downstream side of the indoor expansion valve is also decreased due to the degrees of opening of the indoor expansion valves being narrowed, the difference in pressure between the upstream side and the downstream side of the indoor expansion valve increases and an amount of refrigerant flowing into the indoor unit is increased.

Air conditioner

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.

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.

Refrigeration apparatus and method for controlling the same

A method of controlling an air conditioner includes a step of controlling an opening degree of the expansion valve and/or the number of rotations of an outdoor fan of the outdoor heat exchanger such that the difference Tx (=Te&#x2212;Ti) between the temperature Te of the outdoor heat exchanger and the temperature Ti of the indoor heat exchanger is within a predetermined range, in a cooling mode in a low outside air temperature environment. Specifically, the opening degree of the expansion valve is adjusted, with the number of rotations of the outdoor fan being reduced to be smaller than that in a normal cooling mode, and then, the number of rotations of the outdoor fan is adjusted with the opening degree of the expansion valve being fixed, thereby controlling the difference Tx to be substantially constant.

Method of controlling air conditioner cooling load utilizing controlling the opening degree of an expansion valve and/or the number of rotations of an outdoor fan

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Kawasaki, Japan

Hideya Tamura