Abstract: 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.

Abstract: If the refrigerant amount balance control is executed, 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. On the other hand, 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. Accordingly, cooling ability of the indoor unit increases.

Abstract: An air conditioner 1 of the embodiment of the present invention, when all compressors 21a-21c have been stopping for a given time or more, starts an air conditioning operation without performing pressure equalizing control in switch units 6a-6d with starting the operation of the air conditioner 1. Also, when the stopping time of all compressors 21a-21c is less than the given time, the air conditioner 1 performs the pressure equalizing control by controlling switch units 6a-6d with starting the operation of the air conditioner 1. 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.

Abstract: 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.

Abstract: A CPU 110 compares 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 CPU 110 switches a first three-way valve 22 and a second three-way valve 23 so that a second outdoor heat exchanger 25 is used as a condenser and that a first outdoor heat exchanger 24 is 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 CPU 110 switches the first three-way valve 22 and the second three-way valve 23 so that the first outdoor heat exchanger 24 is used as a condenser and that the second outdoor heat exchanger 25 is not used.

Abstract: When the temperatures of outdoor heat exchangers 23a and 23b detected by outdoor heat exchanger temperature sensors 57a and 57b become equal to or higher than 5 degrees C. and the sucking superheating degrees of compressors 21a and 21b become equal to or lower than 0 degrees C. while an air conditioning apparatus 1 is 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 compressors 21a and 21b are reset. The sucking superheating degrees of the compressors 21a and 21b are obtained by subtracting the low pressure saturation temperatures calculated from the sucking pressures of the compressors 21a and 21b, from the temperatures of the refrigerants sucked into the compressors 21a and 21b which temperatures are detected by the sucking temperature sensors 54a and 54b.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An air conditioning apparatus 1 includes first start control and second start control as its start control. In the first start control, first outdoor heat exchangers 24a, 24b are controlled to function as evaporators and second outdoor heat exchangers 25a, 25b are controlled to function as condensers. Thus, even when the compressors 21a, 21b are 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 compressors 21a, 21b from increasing. Also, after end of the first start control, the first outdoor heat exchangers 24a, 24b and second outdoor heat exchangers 25a, 25b are all controlled to function as evaporators, and the compressors 21a, 21b are 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.

Abstract: 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.

Abstract: 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.

Abstract: An air conditioner 1 of the embodiment of the present invention, when all compressors 21a-21c have been stopping for a given time or more, starts an air conditioning operation without performing pressure equalizing control in switch units 6a-6d with starting the operation of the air conditioner 1. Also, when the stopping time of all compressors 21a-21c is less than the given time, the air conditioner 1 performs the pressure equalizing control by controlling switch units 6a-6d with starting the operation of the air conditioner 1. 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.

Abstract: An air conditioning apparatus 1 includes first start control and second start control as its start control. In the first start control, first outdoor heat exchangers 24a, 24b are controlled to function as evaporators and second outdoor heat exchangers 25a, 25b are controlled to function as condensers. Thus, even when the compressors 21a, 21b are 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 compressors 21a, 21b from increasing. Also, after end of the first start control, the first outdoor heat exchangers 24a, 24b and second outdoor heat exchangers 25a, 25b are all controlled to function as evaporators, and the compressors 21a, 21b are 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.

Abstract: A CPU 110 compares 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 CPU 110 switches a first three-way valve 22 and a second three-way valve 23 so that a second outdoor heat exchanger 25 is used as a condenser and that a first outdoor heat exchanger 24 is 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 CPU 110 switches the first three-way valve 22 and the second three-way valve 23 so that the first outdoor heat exchanger 24 is used as a condenser and that the second outdoor heat exchanger 25 is not used.