JP6015075B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner in which a plurality of outdoor units and a plurality of indoor units are connected by a plurality of refrigerant pipes, and more particularly to an air conditioner that prevents shortage of refrigeration oil in a compressor.

  Conventionally, an air conditioner has been proposed in which a plurality of indoor units are connected in parallel to at least one outdoor unit through a plurality of refrigerant pipes, and each indoor unit can perform a cooling operation or a heating operation. For example, in the air conditioner described in Patent Document 1, two outdoor units are arranged in parallel with a high pressure gas pipe, a low pressure gas pipe, and a liquid pipe in one outdoor unit including two outdoor heat exchangers. It is an air conditioner that is connected and can perform a so-called cooling / heating-free operation that can be performed by selecting a cooling operation and a heating operation for each indoor unit.

  In the above air conditioner, the number of outdoor heat exchangers used in the outdoor unit is selected according to the operating capacity required for the two indoor units, and the request is made for the two indoor units. One of the outdoor heat exchangers is used when the operating capacity is low, and two outdoor heat exchangers are used when the operating capacity required by the two indoor units is high.

  When the air conditioner as described above is installed in a cold area, or when the outside air temperature is low such as early morning or late night in winter (for example, the outside air temperature is 0 ° C. or less), In the compressor provided in the machine, there is a possibility that the refrigerant is dissolved in the compressor refrigeration oil, that is, so-called refrigerant stagnation occurs.

  When the operation of the air conditioner is started in the refrigerant stagnation state and the compressor is started, the refrigerant dissolved in the refrigeration oil evaporates to become a gas refrigerant. And when this gas refrigerant is discharged out of the compressor, the refrigerating machine oil is entrained and the refrigerating machine oil is taken out of the compressor. Therefore, there is a possibility that the refrigerating machine oil is insufficient in the compressor and poor lubrication of the compressor occurs. is there.

  Therefore, in a general air conditioner, the rotation speed of the compressor at the time of start-up is controlled to be a predetermined rotation speed determined in advance to warm the compressor, and this rotation speed is maintained and compression is performed for a predetermined time. By performing start-up control that maintains the drive of the machine, the refrigerant stagnation in the compressor is eliminated.

  By performing the start-up control as described above, the refrigerant stagnation that occurred during the start-up of the compressor is eliminated, and the compressor is poorly lubricated so that the amount of refrigerant oil taken out of the compressor by the gas refrigerant is suppressed. I try not to be.

JP 2004-286253 A (pages 6-7, FIG. 1)

  However, in the air conditioner that performs the start-up control as described above, the pressure inside the compressor rises because the compressor continues to be driven while the start-up control is executed while maintaining the speed of the compressor at a predetermined speed. And if the pressure inside a compressor rises, there existed a possibility that the refrigerant | coolant stagnation resulting from this might generate | occur | produce.

  The present invention solves the problems described above, and provides an air conditioner that can suppress an increase in pressure inside the compressor even if the compressor is continuously driven at a predetermined rotational speed when the air conditioner is started. The purpose is to provide.

  In order to solve the above problems, an air conditioner of the present invention is connected to one end of each of at least one compressor, an oil separator, at least two outdoor heat exchangers, and an outdoor heat exchanger. The flow switching means for switching the connection of the outdoor heat exchanger to the refrigerant discharge port or the refrigerant suction port of the compressor and the other end of each of the outdoor heat exchangers to adjust the refrigerant flow rate in the outdoor heat exchanger Connected to the outdoor unit by at least two refrigerant pipes, and at least one outdoor unit provided with a control unit that performs switching control of the flow path switching valve and opening degree control of the outdoor expansion valve. It has an indoor unit. The outdoor unit has a first solenoid valve, a hot gas bypass pipe and / or a second solenoid valve that connects a high-pressure refrigerant pipe on the discharge side of the compressor and a low-pressure refrigerant pipe on the suction side, and an oil separator and a compressor. And an oil return pipe connected to the suction side of the engine, and the control means has at least one of the first solenoid valve and the second solenoid valve if the first predetermined condition is satisfied when the outdoor unit is started. And the first start-up control for driving the compressor at a predetermined rotational speed is performed.

  According to the air conditioner of the present invention configured as described above, in order to quickly eliminate the refrigerant stagnation state of the compressor, the hot gas bypass pipe or oil return can be performed even if the compressor is continuously driven at a predetermined rotational speed. An increase in the discharge side (high pressure side) pressure of the compressor is suppressed by causing the refrigerant to flow through at least one of the tubes. Thereby, since the pressure rise inside a compressor can be suppressed, generation | occurrence | production of the refrigerant | coolant stagnation resulting from the pressure rise inside a compressor can be suppressed.

It is a refrigerant circuit figure of the air conditioning apparatus which is an Example of this invention, and is a refrigerant circuit figure explaining the flow of the refrigerant | coolant in the case of performing heating operation. It is an outdoor unit schematic in the Example of this invention. FIG. 5 is a refrigerant circuit diagram illustrating a refrigerant flow when performing first activation control in an embodiment of the present invention. It is a refrigerant circuit figure explaining the flow of the refrigerant in the case of performing the 2nd starting control in the example of the present invention. It is a timing chart explaining operation | movement of each part at the time of performing 1st starting control and 2nd starting control in the Example of this invention. It is a flowchart explaining the process in a control means in the Example of this invention. It is a timing chart explaining operation | movement of each part at the time of performing 1st starting control, 2nd starting control, and 3rd starting control in the other Example of this invention. It is a rotation speed table used at the time of 2nd starting control execution in the other Example of this invention. It is a flowchart explaining the process in a control means in the other Example of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, there is provided an air conditioner in which five indoor units are connected in parallel to two outdoor units and can be operated by selecting a cooling operation and a heating operation for each indoor unit. An example will be described. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention.

  As shown in FIG. 1, the air conditioner 1 according to the present embodiment includes two outdoor units 2a and 2b, five indoor units 8a to 8e, five diversion units 6a to 6e, and a branching unit 70. , 71, 72. The outdoor units 2a and 2b, the indoor units 8a to 8e, the diversion units 6a to 6e, the branching units 70, 71 and 72, the high pressure gas pipe 30, the high pressure gas distribution pipes 30a and 30b, the low pressure gas pipe 31, and the low pressure The refrigerant circuit of the air conditioner 1 is comprised by mutually connecting with the gas distribution pipes 31a and 31b, the liquid pipe 32, and the liquid distribution pipes 32a and 32b.

  In this air conditioner 1, in accordance with the open / close state of various valves provided in the outdoor units 2a and 2b and the diversion units 6a to 6e, heating operation (all indoor units are heating operation), heating main operation (heating operation) ) When the overall capacity required for the indoor unit performing cooling exceeds the total capacity required for the indoor unit performing cooling operation, cooling operation (all indoor units are cooling operation), cooling-main operation (cooling operation) Various operation operations are possible, such as when the entire capacity required for the indoor unit performing the heating exceeds the total capacity required for the indoor unit performing the heating operation. In FIG. 1, the case where the heating operation is performed from among these operation operations will be described as an example.

  FIG. 1 is a refrigerant circuit diagram when all the indoor units 8a to 8e are performing the heating operation, and FIG. 2 is a schematic diagram of the outdoor units 2a and 2b. First, the outdoor units 2a and 2b will be described. Since the configurations of the outdoor units 2a and 2b are all the same, only the configuration of the outdoor unit 2a will be described in the following description, and a detailed description of the outdoor unit 2b will not be given. Omitted.

  As shown in FIG. 1 and FIG. 2, the outdoor unit 2a is composed of an electrical component box 10a in which a sheet metal is formed in a box shape and a substrate such as a control board and a power supply board is stored therein, a compressor 21a, and a flow path switching. The output shaft is connected to the first three-way valve 22a and the second three-way valve 23a, the first outdoor heat exchanger 24a, the second outdoor heat exchanger 25a, the outdoor fan 26a, and the outdoor fan 26a. A fan motor 29a for rotating the fan 26a, an accumulator 27a, an oil separator 28a, a first outdoor expansion valve 40a connected to the first outdoor heat exchanger 24a, and a first connected to the second outdoor heat exchanger 25a. Two outdoor expansion valves 41a, a hot gas bypass pipe 36a, a first electromagnetic valve 42a provided in the hot gas bypass pipe 36a, an oil return pipe 37a, and a second electromagnetic valve 4 provided in the oil return pipe 37a It includes a a, and a shut-off valve 44a~46a. The equipment constituting these outdoor units 2a includes the top plate 3a, the bottom plate 4a, the front panel 5a, the front column 7a, the left column 9aa, the right column 9ab, and the fan guard 11a. It is provided inside the housing.

  As shown in FIGS. 2 (A) and 2 (B), the front panel 5a is a steel plate formed by being bent into a substantially L shape when viewed from the upper surface of the outdoor unit 2a, and most of the front surface of the casing of the outdoor unit 2a. It arrange | positions so that a part of front side of the left side surface may be covered. As shown in FIG. 2 (B), the front column 7a is formed of a steel plate provided with a grill 7aa for taking outside air into the outdoor unit 2a, and both ends are bent at a predetermined angle (obtuse angle). The bent portion is arranged so as to cover a part of the front surface of the housing of the outdoor unit 2a and a part of the front surface side of the right side surface. The left column 9aa and the right column 9ab are substantially the same shape, and are steel plates processed into a substantially L-shaped cross section. The left column 9aa is disposed at the rear left corner of the bottom plate 4a, and the right column 9ab is disposed at the rear right corner of the bottom plate 4a.

  The housing left side of the outdoor unit 2a is opened between the side end of the front panel 5a and the left column 9aa and serves as a suction port 13aa for taking outside air into the outdoor unit 2a. The suction port 13aa A lattice-shaped protection member 12aa is provided. In addition, the rear side of the housing of the outdoor unit 2a is opened between the left column 9aa and the right column 9ab, and serves as a suction port 13ab for taking outside air into the outdoor unit 2a. The suction port 13ab has a lattice-like shape. A protection member 12ab is provided. In addition, the right side of the housing 2a has a suction port 13ac for opening outside air between the front column 7a and the right column 9ab to take outside air into the outdoor unit 2a. A protective member 12ac is provided. In addition, the part corresponding to each suction port of the 1st outdoor heat exchanger 24a and the 2nd outdoor heat exchanger 25a is exposed to each suction port 13aa-13ac.

  As shown in FIG. 2 (A), the top plate 3a is a substantially rectangular steel plate, and its peripheral edge is a flange bent downward at a substantially right angle. The top plate 3a is assembled to each upper end of the front panel 5a, the front column 7a, the left column 9aa, and the right column 9ab by screws. The top plate 3a is opened in a circular shape at a position corresponding to the outdoor fan 26a disposed at the upper part of the housing, and the peripheral edge thereof is bent upward at a substantially right angle, and is sucked into the outdoor unit 2a by the outdoor fan 26a. A blower outlet 11a for discharging outside air to the outside is formed. A fan guard 14a is provided at the upper end of the air outlet 11a so as to cover the upper end of the air outlet 11a. The fan motor 29a is fixed to the upper end of the first heat exchanger 24a by a fixing bracket 17a.

  The bottom plate 4a is a substantially rectangular steel plate, and its peripheral edge is a flange bent upward at a substantially right angle. As shown in FIG. 2 (A), the bottom plate 4a is assembled with the lower ends of the front panel 5a, the front-side column 7a, the left-side column 9aa, and the right-side column 9ab by screws. Note that legs 15a are provided on the lower surface of the bottom plate 4a in the front-rear direction so as to extend in the left-right direction of the outdoor unit 2a and to install the outdoor unit 2a on the ground or a rooftop floor.

  The compressor 21a is a variable capacity compressor that can vary its operating capacity by being driven by a motor (not shown) whose rotational speed is controlled by an inverter, and is fixed to the bottom plate 4a as shown in FIG. 2 (A). ing. 1, the discharge side of the compressor 21a is connected to the inflow side of the oil separator 28a by a refrigerant pipe, and the outflow side of the oil separator 28a is an outdoor unit high-pressure gas pipe 33a that is a high-pressure refrigerant pipe. Is connected to the closing valve 44a. The suction side of the compressor 21a is connected to the outflow side of the accumulator 27a by a refrigerant pipe, and the inflow side of the accumulator 27a is connected to the closing valve 45a by an outdoor unit low-pressure gas pipe 34a which is a low-pressure refrigerant pipe. Yes.

  The first three-way valve 22a and the second three-way valve 23a are valves for switching the flow direction of the refrigerant. The first three-way valve 22a has three ports a, b, and c, and the second three-way valve 23a has d, Each of the three ports e and f is provided. In the first three-way valve 22a, the refrigerant pipe connected to the port a is connected to the outdoor unit high-pressure gas pipe 33a at the connection point A. The port b and the first outdoor heat exchanger 24a are connected by a refrigerant pipe, and the refrigerant pipe connected to the port c is connected to the outdoor unit low-pressure gas pipe 34a at a connection point D.

  In the second three-way valve 23, the refrigerant pipe connected to the port d is connected at the connection point A to the refrigerant pipe connected to the outdoor unit high-pressure gas pipe 33a and the port a of the first three-way valve 22a. Further, the port e and the second outdoor heat exchanger 25a are connected by a refrigerant pipe, and the refrigerant pipe connected to the port f is connected to the refrigerant pipe connected to the port c of the first three-way valve 22a at the connection point C. Yes.

  As shown in FIG. 2 (B), the first outdoor heat exchanger 24a and the second outdoor heat exchanger 25a are each formed in a substantially U-shape when viewed from above, and each surface is provided in the outdoor unit 2a. The suction ports 13aa to 13ac are disposed to face each other. Further, the right end portions of the first outdoor heat exchanger 24a and the second outdoor heat exchanger 25a are bent along the surface on which the grill 7aa of the front column 7a is provided. As shown in FIG. 2 (A), the second outdoor heat exchanger 25a is fixed to the bottom plate 4a, and the first outdoor heat exchanger 24a is connected to the upper end of the second outdoor heat exchanger 25a via the fixing bracket 16a. By fixing the lower end of the first outdoor heat exchanger 24a and the second outdoor heat exchanger 25a, the first outdoor heat exchanger 24a and the second outdoor heat exchanger 25a are arranged vertically.

  The first outdoor heat exchanger 24a is composed of a large number of fins 24aa formed of an aluminum material and a plurality of copper tubes 24ab through which a refrigerant flows. Similarly to the first outdoor heat exchanger 24a, the second outdoor heat exchanger 25a includes a large number of fins 25aa formed of an aluminum material and a plurality of copper tubes 25ab formed of a copper material and circulating a refrigerant therein. It is configured.

  As shown in FIG. 1, one end of the first outdoor heat exchanger 24a is connected to the port b of the first three-way valve 22a as described above, and the other end is one of the first outdoor expansion valves 40a via the refrigerant pipe. Connected to the port. The other port of the first outdoor expansion valve 40a is connected to the closing valve 46a and the outdoor unit liquid pipe 35a. Further, as described above, one end of the second outdoor heat exchanger 25a is connected to the port e of the second three-way valve 23a via the refrigerant pipe, and the other end is connected to one of the second outdoor expansion valves 41a via the refrigerant pipe. Connected to the port. The other port of the second outdoor expansion valve 41a is connected to a connection point B in the outdoor unit liquid pipe 35a by a refrigerant pipe.

  The accumulator 27a has an inflow side connected to the outdoor unit low-pressure gas pipe 34a, and an outflow side connected to the suction side of the compressor 21a through a refrigerant pipe. The accumulator 27a separates the inflowing refrigerant into a gas refrigerant and a liquid refrigerant, and causes only the gas refrigerant to be sucked into the compressor 21a.

  The oil separator 28a has an inflow side connected to the discharge side of the compressor 21a by a refrigerant pipe, and an outflow side connected to the outdoor unit high-pressure gas pipe 33a. The oil separator 28a separates the refrigerating machine oil of the compressor 21a included in the refrigerant discharged from the compressor 21a from the refrigerant. The separated refrigerating machine oil is sucked into the compressor 21a through an oil return pipe 37a described later.

  One end of the hot gas bypass pipe 36a is connected to the outdoor unit high-pressure gas pipe 33a at a connection point E, and the other end is connected to the outdoor unit low-pressure gas pipe 34a at a connection point F. The hot gas bypass pipe 36a is provided with a first electromagnetic valve 42a. By opening and closing the first electromagnetic valve 42a, the hot gas bypass pipe 36a can be in a state where the refrigerant flows or does not flow.

  One end of the oil return pipe 37a is connected to the oil return port of the oil separator 28a, and the other end is connected to a refrigerant pipe connecting the suction side of the compressor 21a and the outflow side of the accumulator 27a at a connection point G. The oil return pipe 37a is provided with a second electromagnetic valve 43a. By opening and closing the second electromagnetic valve 43a, the oil return pipe 37a can be in a state where the refrigerant flows or does not flow.

  In addition to the configuration described above, the outdoor unit 2a is provided with various sensors. As shown in FIG. 1, a refrigerant pipe connecting the discharge side of the compressor 21a and the oil separator 28a is discharged from the compressor 21a and a high-pressure sensor 50a that detects the pressure of the refrigerant discharged from the compressor 21a. And a discharge temperature sensor 53a for detecting the temperature of the refrigerant. Between the connection point F in the outdoor unit low-pressure gas pipe 34a and the inflow side of the accumulator 27a, a low-pressure sensor 51a for detecting the pressure of the refrigerant sucked into the compressor 21a and the refrigerant sucked into the compressor 21a An inhalation temperature sensor 54a for detecting the temperature is provided. Further, between the connection point B in the outdoor unit liquid pipe 32a and the closing valve 46a, an intermediate pressure sensor 52a for detecting the pressure of the refrigerant flowing through the outdoor unit liquid pipe 35a and the temperature of the refrigerant flowing through the outdoor unit liquid pipe 35a. Is provided with a refrigerant temperature sensor 55a.

  The refrigerant pipe connecting the port b of the first three-way valve 22a and the first outdoor heat exchanger 24a detects the temperature of the refrigerant flowing out of the first outdoor heat exchanger 24a or flowing into the first outdoor heat exchanger 24a. A first heat exchange temperature sensor 56a is provided. Further, the refrigerant pipe connecting the port e of the second three-way valve 23a and the second outdoor heat exchanger 25a has a temperature of the refrigerant flowing out from the second outdoor heat exchanger 25a or flowing into the second outdoor heat exchanger 25a. A second heat exchange temperature sensor 57a is provided for detecting. Further, an outdoor air temperature sensor 58a that detects the temperature of the outside air flowing into the outdoor unit 2a, that is, the outside air temperature, is provided in the vicinity of any one of the suction ports 13aa to 13ac of the outdoor unit 2a.

  The outdoor unit 2a is provided with a control means 100a. The control means 100a is mounted on a control board (not shown) stored in the electrical component box 10a, and includes a CPU 110a, a storage unit 120a, and a communication unit 130a. CPU110a takes in the detection signal from each sensor mentioned above of outdoor unit 2a, and takes in the control signal output from each indoor unit 8a-8e via communication part 130a. The CPU 110a controls the drive control of the compressor 21a, the switching control of the first three-way valve 22a and the second three-way valve 23a, the rotation control of the fan motor 29a, the first outdoor expansion valve 40a and the first based on the acquired detection signal and control signal. Various controls such as the opening degree control of the two outdoor expansion valves 41a are performed.

The storage unit 120a is composed of a ROM and a RAM, and stores detection values corresponding to control programs for the outdoor unit 2a and detection signals from each sensor. The communication unit 130a is an interface that performs communication between the outdoor unit 2a and the indoor units 8a to 8e.
As shown in FIG. 2A, the electrical component box 10a in which the control means 100a is stored is installed at the upper part of the front side of the outdoor unit 2a (substantially the same height as the first outdoor heat exchanger 24a). Has been.

  The configuration of the outdoor unit 2b is the same as that of the outdoor unit 2a, and the number assigned to the components (devices and members) of the outdoor unit 2a is changed from a to b. It becomes a component of the corresponding outdoor unit 2b. However, the symbols for the connection points of the first three-way valve, the second three-way valve, and the refrigerant pipe are different between the outdoor unit 2a and the outdoor unit 2b, and the port a in the first three-way valve 22a of the outdoor unit 2a. , B, c are ports g, h, j in the first three-way valve 22b of the outdoor unit 2b, and those corresponding to ports d, e, f in the second three-way valve 23a of the outdoor unit 2a are the outdoor units. In the 2b second three-way valve 23b, ports k, m, and n are set. In the outdoor unit 2b, the connection points H, J, K, M, N, P, and Q correspond to the connection points A, B, C, D, E, F, and G in the outdoor unit 2a.

  As shown in FIG. 1, in the refrigerant circuit during the heating operation, each three-way valve is switched so that the two outdoor heat exchangers provided in each of the outdoor units 2a and 2b function as evaporators. Specifically, in the outdoor unit 2a, the first three-way valve 22a is switched to communicate the port b and the port c, and the second three-way valve 23a is switched to communicate the port e and the port f. In the outdoor unit 2b, the first three-way valve 22b is switched so as to communicate between the port h and the port j, and the second three-way valve 23b is switched so as to communicate between the port m and the port n. In FIG. 1, the communication ports of the three-way valves are indicated by solid lines, and the non-communication ports are indicated by broken lines (the same applies to the subsequent refrigerant circuit diagrams (FIGS. 3 and 4)). To show).

  The five indoor units 8a to 8e include indoor heat exchangers 81a to 81e, indoor expansion valves 82a to 82e, and indoor fans 83a to 83e. In addition, since the structure of all the indoor units 8a-8e is the same, in the following description, only the structure of the indoor unit 8a is demonstrated, and description is abbreviate | omitted about the other indoor units 8b-8e.

  One end of the indoor heat exchanger 81a is connected to one port of the indoor expansion valve 82a by a refrigerant pipe, and the other end is connected to a diversion unit 6a described later by a refrigerant pipe. The indoor heat exchanger 81a functions as an evaporator when the indoor unit 8a performs a cooling operation, and functions as a condenser when the indoor unit 8a performs a heating operation.

  The indoor expansion valve 82 a has one port connected to the indoor heat exchanger 81 a as described above, and the other port connected to the liquid pipe 32. When the indoor heat exchanger 81a functions as an evaporator, the indoor expansion valve 82a is adjusted according to the required cooling capacity, and when the indoor heat exchanger 81a functions as a condenser, The opening is adjusted according to the required heating capacity.

  The indoor fan 83a is rotated by a fan motor (not shown), thereby taking in indoor air into the indoor unit 8a, heat-exchanging the refrigerant and indoor air in the indoor heat exchanger 81a, and then transferring the heat-exchanged air indoors. Supply.

  In addition to the configuration described above, the indoor unit 8a is provided with various sensors. A refrigerant temperature sensor 84a for detecting refrigerant temperature is detected in the refrigerant pipe on the indoor expansion valve 82a side of the indoor heat exchanger 81a, and a refrigerant temperature is detected in the refrigerant pipe on the diversion unit 6a side of the indoor heat exchanger 81a. Refrigerant temperature sensors 85a are provided. Further, a room temperature sensor 86a for detecting the temperature of the indoor air flowing into the indoor unit 8a, that is, the room temperature is provided in the vicinity of the indoor air suction port (not shown) of the indoor unit 8a.

  The configurations of the indoor units 8b to 8e are the same as those of the indoor unit 8a, and the numbers given to the constituent elements (devices and members) of the indoor unit 8a are changed from a to b, c, d, and e, respectively. However, it becomes a component of the indoor units 8b-8e corresponding to the component of the outdoor unit 8a.

  The air conditioner 1 includes five branch units 6a to 6e corresponding to the five indoor units 8a to 8e. The diversion units 6a to 6e include electromagnetic valves 61a to 61e, electromagnetic valves 62a to 62e, first diversion pipes 63a to 63e, and second diversion pipes 64a to 64e. In addition, since all the structures of the flow dividing units 6a-6e are the same, in the following description, only the structure of the flow dividing unit 6a is demonstrated and description is abbreviate | omitted about the other flow dividing units 6b-6e.

  One end of the first branch pipe 63 a is connected to the high pressure gas pipe 30, and one end of the second branch pipe 64 a is connected to the low pressure gas pipe 31. Further, the other end of the first diversion pipe 63a and the other end of the second diversion pipe 64a are connected to each other, and the connection portion and the indoor heat exchanger 81a are connected by a refrigerant pipe. The first diverter pipe 63a is provided with an electromagnetic valve 61a, and the second diverter pipe 64a is provided with an electromagnetic valve 62a. By opening and closing the electromagnetic valve 61a and the electromagnetic valve 62a, the diverter unit 6a is provided. The refrigerant flow path in the refrigerant circuit is switched so that the indoor heat exchanger 81a of the corresponding indoor unit 8a is connected to the discharge side (high-pressure gas pipe 30 side) or the suction side (low-pressure gas pipe 31 side) of the compressor 21. be able to.

  The configuration of the diversion units 6b to 6e is the same as that of the diversion unit 6a as described above, and the end of the numbers assigned to the components (devices and members) of the diversion unit 6a is changed from a to b, c, d and e. The components changed to the above are the components of the diversion units 6b to 6e corresponding to the components of the diversion unit 6a.

  The outdoor units 2a and 2b, the indoor units 8a to 8e and the diversion units 6a to 6e described above, the high pressure gas pipe 30, the high pressure gas distribution pipes 30a and 30b, the low pressure gas pipe 31, the low pressure gas distribution pipes 31a and 31b, the liquid pipe 32, The connection state with the liquid distribution pipes 32a and 32b and the branching devices 70, 71, and 72 will be described with reference to FIG. One end of the high-pressure gas branch pipes 30a and 30b is connected to the shut-off valves 44a and 44b of the outdoor units 2a and 2b, respectively, and the other end of the high-pressure gas branch pipes 30a and 30b is connected to the branch device 70, respectively. One end of the high-pressure gas pipe 30 is connected to the branching device 70, and the other end of the high-pressure gas pipe 30 is branched and connected to the first branch pipes 63a to 63e of the branch units 6a to 6e.

  One ends of the low-pressure gas distribution pipes 31a and 31b are connected to the shut-off valves 45a and 45b of the outdoor units 2a and 2b, respectively, and the other ends of the low-pressure gas distribution pipes 31a and 31b are connected to the branch device 71, respectively. One end of the low-pressure gas pipe 31 is connected to the branch 71, and the other end of the low-pressure gas pipe 31 is branched and connected to the second branch pipes 64a to 64e of the branch units 6a to 6e.

  One ends of the liquid distribution pipes 32a and 32b are connected to the closing valves 46a and 46b of the outdoor units 2a and 2b, respectively, and the other ends of the liquid distribution pipes 32a and 32b are connected to the branching device 72, respectively. One end of the liquid pipe 32 is connected to the branching device 72, and the other end of the liquid pipe 32 is branched and connected to refrigerant pipes connected to the indoor expansion valves 82a to 82e of the indoor units 8a to 8e, respectively.

The connection points between the indoor heat exchangers 81a to 81e of the corresponding indoor units 8a to 8e and the first branch pipes 63a to 63e and the second branch pipes 64a to 64e in the branch units 6a to 6e are refrigerant pipes, respectively. Connected.
With the connection described above, the refrigerant circuit of the air conditioner 1 is configured, and the refrigeration cycle is established by flowing the refrigerant through the refrigerant circuit.

  Next, the operation | movement operation | movement of the air conditioning apparatus 1 in a present Example is demonstrated using FIG. In addition, in FIG. 1, when each heat exchanger with which the outdoor units 2a and 2b and indoor unit 8a-8e were equipped becomes a condenser, hatching is attached | subjected, and when it becomes an evaporator, it illustrates in white. Further, the first electromagnetic valves 42a and 42b and the second electromagnetic valves 43a and 43b provided in the outdoor units 2a and 2b, and the electromagnetic valves 61a to 61e and the electromagnetic valves 62a to 62e provided in the flow dividing units 6a to 6e are opened and closed. As for the state, the closed state is illustrated in black, and the open state is illustrated in white. Moreover, the arrow has shown the flow of the refrigerant | coolant.

  As shown in FIG. 1, when all the indoor units 8a to 8e perform heating operation, and the required operation capacity is high and it is necessary to operate all the outdoor units 2a and 2b, in the outdoor unit 2a, The port b and the port c of the first three-way valve 22a are switched so as to communicate with each other, the first outdoor heat exchanger 24a functions as an evaporator, and the port e and the port f of the second three-way valve 23a are switched to communicate with each other. Thus, the second outdoor heat exchanger 25a functions as an evaporator. In the outdoor unit 2b, the port h and the port j of the first three-way valve 22b are switched so as to communicate with each other, and the first outdoor heat exchanger 24b functions as an evaporator, and the port m and the port of the second three-way valve 23b. The second outdoor heat exchanger 25b functions as an evaporator by switching so as to communicate with n. The first electromagnetic valves 42a and 42b and the second electromagnetic valves 43a and 43b of the outdoor units 2a and 2b are both closed, and the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b are both shut off. ing.

  In the indoor units 8a to 8e, the solenoid valves 61a to 61e of the branch units 6a to 6e corresponding to the respective indoor units 8a to 8e are opened so that the refrigerant flows through the first branch pipes 63a to 63e, and the solenoid valves 62a to 62e are closed. The two branch pipes 64a to 64e are shut off. Thereby, all the indoor heat exchangers 81a to 81e of the indoor units 8a to 8e function as a condenser.

  The high-pressure refrigerant discharged from the compressors 21a and 21b flows through the outdoor unit high-pressure gas pipes 33a and 33b via the oil separators 28a and 28b, and flows into the high-pressure gas branch pipes 30a and 30b via the shut-off valves 44a and 44b. . The high-pressure refrigerant that has flowed into the high-pressure gas branch pipes 30a and 30b joins at the branching device 70, flows through the high-pressure gas pipe 30, and flows into the branch units 6a to 6e from the high-pressure gas pipe 30.

  The high-pressure refrigerant that has flowed into the diversion units 6a to 6e flows through the first diversion pipes 63a to 63e provided with the open electromagnetic valves 61a to 61e, flows out of the diversion units 6a to 6e, and flows into the diversion units 6a to 6e. Flows into the indoor units 8a to 8e corresponding to 6e.

  The high-pressure refrigerant flowing into the indoor units 8a to 8e flows into the indoor heat exchangers 81a to 81e, exchanges heat with the indoor air, and condenses. Thereby, room air is warmed and the room in which indoor unit 8a-8e was installed is heated. The high-pressure refrigerant that has flowed out of the indoor heat exchangers 81a to 81e passes through the indoor expansion valves 82a to 82e and is depressurized. The opening degree of the indoor expansion valves 82a to 82e is determined in accordance with the degree of supercooling of the refrigerant at the refrigerant outlet of the indoor heat exchangers 81a to 81e. The degree of supercooling of the refrigerant is determined, for example, from a high-pressure saturation temperature (corresponding to the condensation temperature in the indoor heat exchangers 81a to 81e) calculated from the pressure detected by the high-pressure sensors 50a and 50b of the outdoor units 2a and 2b. It is obtained by subtracting the refrigerant temperature at the refrigerant outlet of the indoor heat exchangers 81a to 81e detected by 84a to 84e.

  The intermediate-pressure refrigerant that has flowed out of the indoor units 8a to 8e flows into the liquid pipe 32, joins in the liquid pipe 32, and flows into the branching device 72. The intermediate-pressure refrigerant branched from the branching device 72 to the liquid distribution pipes 32a and 32b flows into the outdoor units 2a and 2b via the closing valves 46a and 46b. The intermediate-pressure refrigerant that has flowed into the outdoor units 2a and 2b flows through the outdoor unit liquid pipes 35a and 35b, and is divided at the connection points B and J to be divided into the first outdoor expansion valves 40a and 40b and the second outdoor expansion valves 41a and 41b. The refrigerant is reduced in pressure through a low pressure refrigerant.

  The opening degree of the first outdoor expansion valves 40a, 40b is determined according to the degree of superheat of the refrigerant at the refrigerant outlet of the first outdoor heat exchangers 24a, 24b. The opening degree of the second outdoor expansion valves 41a and 41b is determined according to the degree of superheat of the refrigerant at the refrigerant outlet of the second outdoor heat exchangers 25a and 25b. The degree of superheat of the refrigerant is, for example, that of the first outdoor heat exchangers 24a and 24b and the second outdoor heat exchangers 25a and 25b detected by the first heat exchange temperature sensors 56a and 56b and the second heat exchange temperature sensors 57a and 57b. Low pressure saturation temperature calculated from the pressure detected by the low pressure sensors 51a and 51b of the outdoor units 2a and 2b from the refrigerant temperature at the refrigerant outlet (inside the first outdoor heat exchangers 24a and 24b and in the second outdoor heat exchangers 25a and 25b) Is equivalent to the evaporation temperature of

  The low-pressure refrigerant depressurized by the first outdoor expansion valves 40a and 40b and the second outdoor expansion valves 41a and 41b flows into the first outdoor heat exchangers 24a and 24b and the second outdoor heat exchangers 25a and 25b, and the outside air Evaporate with heat exchange. The low-pressure refrigerant flowing out of the first outdoor heat exchangers 24a and 24b and the second outdoor heat exchangers 25a and 25b is connected to the connection point C via the first three-way valves 22a and 22b and the second three-way valves 23a and 23b. , K, and is sucked into the compressors 21a and 21b via the connection points F and P and the accumulators 27a and 27b and compressed again.

  Next, with reference to FIGS. 1 to 5, the operation of the refrigerant circuit according to the present invention and the operation and effect thereof in the air-conditioning apparatus 1 of the present embodiment will be described. In the following description, the air conditioner 1 is activated and the heating operation described with reference to FIG. 1 is started, and all the indoor units 8a to 8e and all the outdoor units 2a and 2b are operated. A case will be described as an example.

  For example, when the air conditioner 1 is installed in a cold region, or when the outside air temperature is low (for example, 0 ° C. or less) such as late at night or early morning in winter, the compressors 21a and 21b are stopped inside. There is a possibility that so-called refrigerant stagnation occurs in a state where the refrigerant is dissolved in the refrigeration oil of the compressors 21a and 21b. When the compressors 21a and 21b are started in this state, the refrigerant dissolved in the refrigerating machine oil evaporates to become a gas refrigerant, and when the gas refrigerant is discharged from the compressors 21a and 21b, the refrigerating machine oil is involved and the compressor 21a , 21b, the refrigerant oil may be insufficient in the compressors 21a and 21b.

  In the present embodiment, in order to solve the above problems, at the time of starting the air conditioner 1, mainly the refrigerant stagnation in the compressors 21a and 21b is eliminated and the amount of refrigerating machine oil discharged together with the refrigerant is reduced. The first startup control is performed and the second startup control is performed mainly to shorten the rise time of the heating operation capacity. Hereinafter, the first activation control and the second activation control will be described in detail.

[First start control]
The air conditioning apparatus 1 starts the heating operation in response to an operation start instruction or a timer activation instruction by the user. The CPUs 110a and 110b of the control means 100a and 100b of the outdoor units 2a and 2b that have received the operation start instruction via the indoor units 8a to 8e satisfy the start condition of the first activation control that is the first predetermined condition. If it is established, the first activation control is started. Here, the start condition of the first activation control is, for example, that the outside air temperature is a predetermined temperature (for example, 5 ° C.) or less and the compressors 21a and 21b are continuously stopped for a predetermined time (for example, one hour) or more. As shown in FIG. 5, the refrigerant 21 may be stagnation in the compressors 21a and 21b. In addition, when the start conditions of 1st starting control are not satisfied, CPU110a, 110b controls outdoor unit 2a, 2b corresponding to normal air-conditioning control.

  As shown in FIG. 5, the CPUs 110 a and 110 b control the rotational speed of the compressors 21 a and 21 b and switch the functions of the first outdoor heat exchangers 24 a and 24 b and the second outdoor heat exchangers 25 a and 25 b (see FIG. 5). (Evaporator / condenser switching) control, opening control of first outdoor expansion valves 40a, 40b and second outdoor expansion valves 41a, 41b, and opening / closing control of first electromagnetic valves 42a, 42b and second electromagnetic valves 43a, 43b. Do.

  Specifically, as shown in FIG. 3, the CPU 110a allows the first three-way valve 22a to communicate the port b and the port c so that the first outdoor heat exchanger 24a functions as an evaporator. The two-way valve 23a allows the port d and the port e to communicate with each other so that the second outdoor heat exchanger 25a functions as a condenser. Further, the CPU 110b communicates the first three-way valve 22b with the port h and the port j so that the first outdoor heat exchanger 24b functions as an evaporator, and the second three-way valve 23b has the port k and the port m. And the second outdoor heat exchanger 25b functions as a condenser.

  Then, the CPUs 110a and 110b start the compressors 21a and 21b at a starting rotation speed that is a predetermined rotation speed determined in advance, for example, 70 rps as shown in FIG. To maintain. When the compressors 21a and 21b are started, as shown in FIG. 3, the high-pressure refrigerant discharged from the compressors 21a and 21b flows through the outdoor unit high-pressure gas pipes 33a and 33b via the oil separators 28a and 28b. , The flow is divided at connection points A and H, one flows to the indoor units 8a to 8e via the closing valves 44a and 44b, and the other functions as a condenser via the second three-way valves 23a and 23b. It flows into the heat exchangers 25a and 25b.

  The high-pressure refrigerant flowing into the second outdoor heat exchangers 25a and 25b exchanges heat with the outside air to condense, and as shown in FIG. 5, the second outdoor expansion valves 41a and 41b that are fully opened by the CPUs 110a and 110b are opened. Passed and depressurized. The intermediate-pressure refrigerant that has passed through the second outdoor expansion valves 41a and 41b merges with the intermediate-pressure refrigerant that has flowed from the indoor units 8a to 8e at the connection points B and J, and is predetermined by the CPUs 110a and 110b as shown in FIG. The pressure is reduced by passing through the first outdoor expansion valves 40a and 40b.

  Here, the opening degree of the first outdoor expansion valves 40a, 40b depends on the degree of superheat of the refrigerant at the refrigerant outlet (the first three-way valve 22a, 22b side) of the first outdoor heat exchangers 24a, 24b by the CPUs 110a, 110b. Control. The degree of superheat of the refrigerant is, for example, a low pressure calculated from the pressure detected by the low pressure sensors 51a and 51b from the refrigerant temperature at the refrigerant outlet of the first outdoor heat exchangers 24a and 24b detected by the first heat exchange temperature sensors 56a and 56b. It is obtained by subtracting the saturation temperature (corresponding to the evaporation temperature in the first outdoor heat exchangers 24a and 24b).

  The low-pressure refrigerant that has passed through the first outdoor expansion valves 40a and 40b evaporates by exchanging heat with the outside air in the first outdoor heat exchangers 24a and 24b, and passes through the first three-way valves 22a and 22b and the accumulators 27a and 27b. Then, it is sucked into the compressors 21a and 21b. Further, as shown in FIG. 5, the CPUs 110a and 110b open the first electromagnetic valves 43a and 43b so that the refrigerant flows through the hot gas bypass pipes 36a and 36b. As shown in FIG. 5, the second electromagnetic valves 44a and 44b are opened when the outdoor units 2a and 2b are stopped, and the second electromagnetic valve 44a is also used when the first activation control is executed. , 44b are maintained open, and the oil return pipes 37a, 37b are brought into a state where the refrigerant flows.

  When there is a possibility that the refrigerant stagnation occurs in the compressors 21a and 21b, when the air conditioner 1 is started, the rotation speed at the start-up is a predetermined rotation speed that is a predetermined rotation speed of the compressors 21a and 21b. It is desirable to quickly separate the refrigerant dissolved in the refrigerating machine oil from the refrigerating machine oil by quickly increasing the temperature of the compressors 21a and 21b by performing start-up control that is driven as a number. Here, in consideration of the discharge amount of the refrigerating machine oil that increases with the increase in the rotation speed of the compressor, the start-up rotation speed is set as high as possible within a range where the discharge amount of the refrigerating machine oil becomes a predetermined amount or less. Determine. However, if the driving of the compressors 21a and 21b is continued at the starting rotation speed, the pressure in the compressors 21a and 21b increases, and the refrigerant stagnation due to this may occur in the compressors 21a and 21b. .

  In contrast, in the first start-up control of the present invention, when the compressors 21a and 21b are driven while maintaining the rotation speed at the start-up rotation speed, the second start-up control is the second of the two outdoor heat exchangers. Since the outdoor heat exchangers 25a and 25b function as condensers, an increase in high pressure (pressure on the discharge side of the compressors 21a and 21b) can be suppressed.

  Further, when performing the first activation control, the first electromagnetic valves 43a and 43b and the second electromagnetic valves 44a and 44b are opened so that the refrigerant flows through the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b. . Since the hot gas bypass pipes 36a and 36b bypass the outdoor unit high-pressure gas pipes 33a and 33b and the outdoor unit low-pressure gas pipe 34a, as shown by broken line arrows in FIG. As the refrigerant flows from the connection point N toward P, an increase in high pressure (pressure on the discharge side of the compressors 21a and 21b) is suppressed. The oil return pipes 37a and 37b also bypass the outdoor unit high-pressure gas pipes 33a and 33b and the outdoor unit low-pressure gas pipe 34a via the oil separators 28a and 28b. The refrigerant flows together with the refrigeration oil from the separators 28a and 28b to the compressors 21a and 21b, thereby suppressing an increase in high pressure (pressure on the discharge side of the compressors 21a and 21b).

  As described above, in the first start-up control, the CPUs 110a and 110b cause the second outdoor heat exchangers 25a and 25b to function as condensers, and the refrigerant passes through the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b. Since it is in a flowing state, an increase in high pressure is suppressed, and an increase in pressure in the compressors 21a and 21b can be suppressed even if the compressors 21a and 21b are continuously driven at the starting rotational speed. Therefore, it is possible to suppress the occurrence of refrigerant stagnation in the compressors 21a and 21b due to the pressure increase in the compressors 21a and 21b.

  In the first activation control described above, the second outdoor heat exchangers 25a and 25b function as condensers, and the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b are in a state in which the refrigerant flows. If one of the controls can suppress an increase in pressure in the compressors 21a and 21b that is caused by continuing to drive the compressors 21a and 21b at the starting rotational speed, only one of the controls is controlled. May be performed. Further, the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b are controlled so that the refrigerant flows. However, by setting one of the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b to a state where the refrigerant flows, the compressors 21a and 21b May be controlled so that only one of the refrigerant flows when the pressure increase in the compressors 21a and 21b due to continuing to be driven at the starting rotational speed can be suppressed.

  In the first activation control, of the two outdoor heat exchangers, the first outdoor heat exchangers 24a and 24b function as an evaporator. As shown in FIG. 2, the first outdoor heat exchangers 24a and 24b are disposed closer to the outdoor fans 26a and 26b than the second outdoor heat exchangers 25a and 25b.

  If the outdoor heat exchanger functioning as an evaporator has insufficient evaporation capability, a liquid refrigerant that has not been evaporated by the outdoor heat exchanger may be sucked into the compressor, so-called liquid back may occur. The compressor may break down due to the compression.

  In order to suppress the liquid back due to the lack of evaporation capability as described above, in the first start-up control, the second outdoor heat exchanger 25a, by being arranged on the upper part of the second outdoor heat exchanger 25a, 25b, The first outdoor heat exchangers 24a and 24b, which are arranged closer to the outdoor fans 26a and 26b than 25b, function as an evaporator. Since the amount of outdoor air taken into the outdoor units 2a and 2b increases near the outdoor fans 26a and 26b, the evaporation capacity of the first outdoor heat exchangers 24a and 24b is the second outdoor heat exchanger. This is higher than when 25a and 25b function as an evaporator.

  Therefore, it is possible to suppress the occurrence of liquid back due to the lack of evaporation capability in the first outdoor heat exchangers 24a and 24b functioning as an evaporator. As described above, the opening degree of the first outdoor expansion valves 40a and 40b corresponding to the first outdoor heat exchangers 24a and 24b functioning as an evaporator is the refrigerant of the first outdoor heat exchangers 24a and 24b. Since it is controlled according to the degree of superheat of the refrigerant at the outlet (first three-way valve 22a, 22b side), the evaporation capacity in the first outdoor heat exchangers 24a, 24b can be further secured and the occurrence of liquid back Can be more effectively suppressed.

  When executing the first activation control, the CPUs 110a and 110b determine whether an end condition for the first activation control, which is a second predetermined condition, is satisfied. 1 Start control is complete | finished and it transfers to 2nd start control demonstrated below. The end condition of the first start control is, for example, that the discharge superheat degree of the compressors 21a and 21b after a predetermined time (for example, 1 minute) from the start of the first start process is equal to or higher than a predetermined temperature (for example, 8 ° C.). It is a condition that the refrigerating machine oil discharged together with the refrigerant from the compressors 21a and 21b can be suppressed to some extent as shown in FIG. In addition, the discharge superheat degree of the compressors 21a and 21b is determined from the refrigerant temperature detected by the discharge temperature sensors 53a and 53b and the high pressure saturation temperature (second outdoor heat exchanger 25a, It can be determined by subtracting the condensing temperature in 25b).

[Second startup control]
The CPUs 110a and 110b start the second activation control following the first activation control. As described above, the refrigerant stagnation state in the compressors 21a and 21b is eliminated to some extent by the first start-up control, and the discharge amount of the refrigerating machine oil does not hinder the lubrication of the compressors 21a and 21b. In the start-up control, various controls are performed to reduce the rise time of the air-conditioning operation capability while reducing the refrigerant stagnation amount in the compressors 21a and 21b. Therefore, in the first start-up control, the functions of the two outdoor heat exchangers are made different so that the evaporator and the condenser are mixed in the outdoor unit. However, in the second start-up control, the operation mode is the heating operation / heating main In the case of operation, both of the outdoor heat exchangers function as an evaporator, and in the case of cooling operation / cooling main operation, both of the outdoor heat exchangers function as a condenser.

  In the present embodiment, since the air conditioner 1 performs the heating operation, the CPUs 110a and 110b perform the rotation speed control of the compressors 21a and 21b and the second outdoor heat exchanger 25a as shown in FIG. , 25b function switching (switching from the condenser to the evaporator. The first outdoor heat exchangers 24a, 24b are maintained as evaporators in the first start-up control), control, the first outdoor expansion valve 40a, 40b and the second outdoor expansion valves 41a and 41b, and the opening and closing control of the first electromagnetic valves 42a and 42b and the second electromagnetic valves 43a and 43b are performed.

  Specifically, as shown in FIG. 4, the CPUs 110a and 110b communicate the port e and the port f with the second three-way valve 23a, and the port m and the port n with the second three-way valve 23b. The second outdoor heat exchangers 25a and 25b are switched so as to function as an evaporator. Further, as shown in FIG. 5, the CPUs 110 a and 110 b continue to drive the compressors 21 a and 21 b while maintaining the rotation speed at startup, 70 rps, and the first electromagnetic valves 43 a and 43 b and the second electromagnetic valves 44 a, The state where 44b is opened is maintained, and the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b are maintained in a state where the refrigerant flows.

  Further, as shown in FIG. 5, the CPUs 110a and 110b control the opening degree of the first outdoor expansion valves 40a and 40b in accordance with the degree of superheat of the refrigerant at the refrigerant outlet of the first outdoor heat exchangers 24a and 24b. The opening degree of the second outdoor expansion valves 41a and 41b is controlled according to the degree of superheat of the refrigerant at the refrigerant outlet of the second outdoor heat exchangers 25a and 25b. The refrigerant circuit at the time of executing the second start control shown in FIG. 4 is the refrigerant circuit described in FIG. 1 except for the states of the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b (the refrigerant flows / does not flow). Therefore, detailed description of the refrigerant flow and the like is omitted.

  In the second start-up control, as described above, the second outdoor heat exchangers 25a and 25b functioning as condensers when the first start-up control is executed are switched to function as evaporators, and the compressors 21a and 21b are started up. The system continues to be driven while maintaining the rotational speed of 70 rpm. Since the compressors 21a and 21b are warmed by the first start-up control, the compressor 21a and 21b have a high pressure by maintaining the rotation speed at the start-up even without the condenser from the refrigerant circuit. The amount of refrigerant stagnation is reduced. Accordingly, in the second start-up control, the first outdoor heat exchangers 24a and 24b and the second outdoor heat exchangers 25a and 25b are both used as an evaporator, that is, the compressors 21a and 21b are used as a refrigerant circuit during heating operation at 70 rps. By maintaining and driving the compressor 21a, 21b, it is possible to warm the compressors 21a, 21b and further reduce the amount of refrigerant stagnation in the compressors 21a, 21b, while shortening the rise time of the heating operation capacity.

  Moreover, when switching the 2nd outdoor heat exchanger 25a, 25b which was functioning as a condenser so that it may function as an evaporator, a high voltage | pressure rises transiently and compressor 21a, 21b originates in this. The compression ratio may increase, and the compressors 21a and 21b may be damaged by the increase in the compression ratio. Therefore, in the second activation control, as shown in FIG. 5, the first electromagnetic valves 42a and 42b and the second electromagnetic valves 43a and 43b, which are opened when the first activation control is executed, are continuously set for a predetermined time (for example, 2 minutes). Open until the transient high pressure rise is settled. Thereby, since the hot gas bypass pipes 36a and 36b and the oil return pipes 37a and 37b are in a state in which the refrigerant flows, an increase in the high pressure can be suppressed, so that an increase in the compression ratio of the compressors 21a and 21b can be suppressed. Damage to the machines 21a and 21b can be prevented.

  In the second start-up control, the second outdoor heat exchangers 25a and 25b are switched from the state functioning as a condenser to the state functioning as an evaporator, so the first three-way valve of the second outdoor heat exchangers 25a and 25b. The 22a and 22b sides are connected to the suction sides of the compressors 21a and 21b. At this time, liquid refrigerant that stays in the second outdoor heat exchangers 25a and 25b when functioning as a condenser and does not evaporate when switched as an evaporator is connected to the second three-way valves 23a and 23b. It flows to the outdoor unit low-pressure gas pipes 34a and 34b via points C and K.

  In this state, for example, if the compressor 21b is stopped, the liquid refrigerant that has accumulated in the second outdoor heat exchanger 25b passes through the connection points K and M from the second three-way valve 23b. Flows into the outdoor unit low-pressure gas pipe 34b, flows in the order of the low-pressure gas distribution pipe 31b → the branching device 71 → the low-pressure gas distribution pipe 31a, and flows into the outdoor unit 2a. The liquid refrigerant that has flowed into the outdoor unit 2a flows through the outdoor unit low-pressure gas pipe 34a and flows into the accumulator 27a through the connection point F. As a result, there is a possibility that the refrigerant concentrates on the outdoor unit 2a including the driven compressor 21a and the accumulator 27a overflows.

  Therefore, in the second start-up control of the present invention, all the compressors that have been driven in the first start-up control, in the present embodiment, the compressors 21a and 21b are continuously driven in the second start-up control. As a result, when the second outdoor heat exchangers 25a and 25b are switched from the state functioning as a condenser to the state functioning as an evaporator, the liquid refrigerant staying in the second outdoor heat exchangers 25a and 25b is It flows into each accumulator 27a, 27b. Therefore, it is possible to prevent a problem that the refrigerant concentrates on any outdoor unit and overflows in the accumulator.

  When executing the second activation control, the CPUs 110a and 110b determine whether or not the termination condition for the second activation control is satisfied. If the conditions are satisfied, the CPU 110a ends the second activation control. Then, the start-up control of the air conditioner 1 is finished and the routine proceeds to normal air conditioning control. The end condition of the second start control is, for example, that the discharge superheat degree of the compressors 21a and 21b after a predetermined time (for example, 1 minute) from the start of the second start process is equal to or higher than a predetermined temperature (for example, 12 ° C.). It is the condition that the refrigerant stagnation in the compressors 21a and 21b is eliminated and the refrigerating machine oil discharged together with the refrigerant disappears.

  Next, the flow of processing in the air conditioner 1 according to the present embodiment will be described using the flowchart shown in FIG. The flowchart shown in FIG. 6 shows the flow of processing relating to the first activation control and the second activation control performed when the air conditioner 1 is activated, ST represents a step, and the number following this represents a step number. ing. Note that FIG. 6 mainly describes the processes related to the present invention, and other general processes such as control of the refrigerant circuit corresponding to the operating conditions such as the set temperature and the air volume instructed by the user are described. Is omitted. Further, since the processes related to the first activation control and the second activation control performed by the CPUs 110a and 110b are the same, in the following description, the first activation control and the second activation performed by the CPU 110a provided in the control means 100a of the outdoor unit 2a. Processing related to control will be described.

  Receiving the operation start instruction, the CPU 110a determines whether or not the above-described start condition for the first activation control is satisfied (ST1). If the start condition of the first activation control is satisfied (ST1-Yes), the CPU 110a controls the first three-way valve 22a so that the first outdoor heat exchanger 24a functions as an evaporator, and the second outdoor heat. The second three-way valve 23a is controlled so that the exchanger 25a functions as an evaporator (ST2).

  Next, the CPU 110a controls to start the compressor 21a at the starting rotation speed or to continue driving (ST3).

  Next, the CPU 110a controls the opening degree of the first outdoor expansion valve 40a according to the refrigerant superheat degree at the refrigerant outlet of the first outdoor heat exchanger 24a, and fully opens the second outdoor expansion valve 41a (ST4). .

  Next, the CPU 110a opens the first electromagnetic valve 42a (ST5), and puts the refrigerant in the hot gas bypass 36a. As described above, the second electromagnetic valve 43a is opened from the time when the outdoor unit 2a is stopped, and the CPU 110a maintains this state and causes the oil return pipe 37a to flow into the refrigerant.

  Next, CPU 110a determines whether or not an end condition for the first activation control is satisfied (ST6). If the end condition of the first activation control is not satisfied (ST6-No), the CPU 110a returns the process to ST2 and continues the first activation control.

  If the termination condition for the first activation control is satisfied (ST6-Yes), the CPU 110a terminates the first activation control and shifts to the second activation control. CPU 110a determines whether or not the operation mode instructed by the user is a heating operation or a heating main operation (ST7).

  If the operation mode instructed by the user is the heating operation or the heating-main operation (ST7-Yes), the CPU 110a switches the second outdoor heat exchanger 25a functioning as a condenser to function as an evaporator (ST8). ). Next, the CPU 110a controls the opening degree of the first outdoor expansion valve 40a in accordance with the degree of refrigerant superheating at the refrigerant outlet of the first outdoor heat exchanger 24a, and the opening degree of the second outdoor expansion valve 41a in the second outdoor area. Control is performed according to the degree of refrigerant superheat at the refrigerant outlet of the heat exchanger 25a (ST9).

  Next, the CPU 110a starts a timer after the end of the first activation control, and determines whether or not a predetermined time, for example, 2 minutes has elapsed since the end of the first activation control (ST10). If the predetermined time has not elapsed since the end of the first activation control (ST10-No), the CPU 110a returns the process to ST7.

  If the predetermined time has elapsed from the end of the first activation control (ST10-Yes), the CPU 110a closes the first electromagnetic valve 42a and the second electromagnetic valve 43a (ST11), and the hot gas bypass pipe 36a and the oil return pipe Block 37a.

  Next, CPU 110a determines whether or not an end condition for the second activation control is satisfied (ST12). If the end condition for the second start control is not satisfied (ST12-No), the CPU 110a continuously drives the compressors 21a and 21b at the start rotation speed (ST14), and returns the process to ST12 to return to the second. Continue startup control. If the termination condition of the second activation control is satisfied (ST12-Yes), the CPU 110a terminates the second activation control, that is, terminates the activation control of the air conditioner 1, and starts normal air conditioning control.

  In ST1, if the start condition for the first activation control is not satisfied (ST1-No), the CPU 110a ends without performing the activation control and starts the normal air conditioning control.

  In ST7, if the operation mode instructed by the user is not the heating operation or the heating main operation (ST7-No), the operation mode instructed by the user is the cooling operation or the cooling main operation. The first outdoor heat exchanger 24a functioning as a condenser is switched to function as a condenser (ST12). Next, the CPU 110a fully opens the opening degree of the first outdoor expansion valve 40a or controls it according to the degree of refrigerant subcooling at the refrigerant outlet of the first outdoor heat exchanger 24a, and opens the second outdoor expansion valve 41a. The degree is fully opened or controlled according to the degree of refrigerant supercooling at the refrigerant outlet of the second outdoor heat exchanger 25a (ST13). And CPU110a advances a process to ST10.

  Next, a second embodiment of the air conditioner of the present invention will be described. In the present embodiment, the configuration and operation of the air conditioner and the start conditions for the start control that is performed when the air conditioner is started are the same as those in the first embodiment, and thus the description thereof is omitted. The difference from the first embodiment is that a control for reducing the rotational speed of the compressor is inserted between the first start control and the second start control in the first embodiment.

  Below, the operation | movement of the refrigerant circuit concerning this invention, its effect | action, and an effect are demonstrated in the air conditioning apparatus 1 of a present Example using FIG. 1 thru | or FIG. 4, FIG. 7, and FIG. In the following description, as in the case of the first embodiment, the air conditioner 1 is activated and the heating operation described with reference to FIG. 1 is started, and all the indoor units 8a to 8e are started. A case where all the outdoor units 2a and 2b are operated will be described as an example.

  In the first embodiment, when the start condition of the start control (start condition of the first start control) is satisfied when the air conditioner 1 starts the heating operation, the CPUs 110a and 110b perform the first start control. And the second activation control is continued after the first activation control is completed. When the first start control is shifted to the second start control, the second outdoor heat exchangers 25a and 25b functioning as condensers in the first start control are switched so as to function as evaporators. Thereby, since there is no outdoor heat exchanger functioning as a condenser, the high pressure (pressure on the discharge side of the compressors 21a and 21b) increases.

  At this time, when the outside air temperature is relatively high (for example, −9 ° C. or higher), the second outdoor heat exchangers 25a and 25b functioning as condensers are switched so as to function as evaporators. Condensation capacity decreases. As a result, the high pressure increases and the operating load of the compressors 21a and 21b increases, which may exceed the upper limit value of the discharge pressure of the compressors 21a and 21b. The compressors 21a and 21b are stopped and the discharge pressure increases. There is a risk that overload protection control is performed to suppress this.

  In this embodiment, in order to solve the above problems, as shown in FIG. 7, when the air conditioner 1 is started, the refrigerant stagnation mainly in the compressors 21a and 21b is eliminated and discharged together with the refrigerant. The first start control (the same control as the first start control in the first embodiment) performed to reduce the amount of refrigeration oil, and the first performed mainly to suppress the increase in the discharge pressure of the compressors 21a and 21b. 2 start-up control and third start-up control performed mainly to shorten the rise time of the heating operation capacity (except for the rotational speed control of the compressors 21a and 21b, the same control as the second start-up control in the first embodiment) ).

  Hereinafter, each of the above-described activation controls will be described in detail, but the first activation control is the same as the first activation control in the first embodiment including the start condition and the end condition, and thus the description thereof is omitted. . The third start-up control is the same as the second start-up control in the first embodiment except for the rotational speed control of the compressors 21a and 21b, which will be described later. Therefore, the description of the same control is omitted. Further, the description will be made assuming that the lower limit rotational speed in the rotational speed range allowed by the compressors 21a and 21b is 20 rps.

[Second startup control]
CPU110a, 110b will start 2nd starting control following 1st starting control, if the end conditions of 1st starting control are satisfied. In the second startup control, the rotational speed of the compressors 21a and 21b is changed from 70 rps, which is the rotational speed when the first startup control is executed (starting speed), to a predetermined rotational speed X (rps) according to the outside air temperature. The discharge pressure of the compressors 21a and 21b is reduced by reducing the pressure at a predetermined rate.

  A rotational speed table 200 shown in FIG. 8 is stored in advance in the storage units 120a and 120b corresponding to the CPUs 110a and 110b, respectively. The rotational speed table 200 is used to determine the rotational speed X (rps) of the compressors 21a and 21b in accordance with the outside air temperature T (° C.) at the time when the second start-up control is executed. If the rotational speed of the compressors 21a and 21b is reduced to the rotational speed X by performing the above, it is confirmed that the upper limit value of the discharge pressure in the compressors 21a and 21b at the outside air temperature T is not exceeded. is there.

  In the rotation speed table 200, the outside air temperature T is divided by 1 ° C. between “−10 ° C. or lower” and “11 ° C. or higher”. The rotational speed X is determined in correspondence with the outside air temperature T. Specifically, when the outside air temperature T is “−10 ° C. or lower”, the compressor 21a, 21b is less likely to exceed the upper limit value of the discharge pressure, so the rotational speed X is the same as the rotational speed at startup “70 rps”. "

  Further, when the outside air temperature T is higher than −10 ° C., there is a concern that the upper limit value of the discharge pressure may be exceeded in the compressors 21a and 21b, and the higher the outside air temperature T, the higher the possibility of exceeding the upper limit value of the discharge pressure. Therefore, in the rotation speed table 200, it is determined that the rotation speed X becomes lower as the outside air temperature T becomes higher. For example, when the outside air temperature T is −5 ° C., the rotation speed X is 58 rps, and the outside air temperature T is 0. The rotational speed X at 46 ° C. is 46 rps, the rotational speed X at 35 ° C. when the outside air temperature T is 5 ° C., and so on. When the outside air temperature T is “11 ° C. or higher”, the rotational speed X is “20 rps” which is the lower limit rotational speed.

  Next, a specific operation of each component of the outdoor units 2a and 2b when executing the second activation control will be described. As shown in FIG. 7, the CPU 110a and the CPU 110b control the rotational speed of the compressors 21a and 21b and switch the functions of the first outdoor heat exchangers 24a and 24b and the second outdoor heat exchangers 25a and 25b (see FIG. 7). (Evaporator / condenser switching) control, opening control of the first outdoor expansion valves 40a, 40b and second outdoor expansion valves 41a, 41b, and opening / closing control of the first electromagnetic valves 42a, 42b and second electromagnetic valves 43a, 43b. Do.

  Of the controls in the second start-up control described above, the control other than the rotation speed control of the compressors 21a and 21b is the same as the first start-up control, and the description thereof is omitted. Hereinafter, the control of the compressors 21a and 21b is omitted. The rotation speed control will be described in detail. The state of the refrigerant circuit of the air conditioner 1 when performing the second activation process is the same as that when performing the first activation control in the first embodiment, that is, the state shown in FIG.

  In the storage units 120a and 120b, the outside air temperatures detected at predetermined timings (for example, every 2 seconds) by the outside air temperature sensors 58a and 58b, which are outside air temperature detecting means provided in the outdoor units 2a and 2b, are time-series. I remember it. When starting the second activation control, the CPUs 110a and 110b take in the outdoor air temperature T stored last from the outdoor air temperatures stored in the storage units 120a and 120b. The CPUs 110a and 110b similarly refer to the rotation speed table 200 stored in the storage units 120a and 120b, and extract the rotation speed X corresponding to the taken-in outside air temperature T from the rotation speed table 200.

  Next, the CPUs 110a and 110b reduce the rotational speeds of the compressors 21a and 21b from the current rotational speed, that is, the rotational speed X that is extracted from the starting rotational speed of 70 rps, at a predetermined rate. For example, if the outside air temperature T is 0 ° C. and the predetermined rate for reducing the rotation speed is 2 rps / second, the rotation speed X when the outside air temperature T is 0 ° C. is 46 rps from the rotation speed table 200, so the CPU 110 a , 110b reduces the rotational speed of the compressors 21a, 21b to 46 rps in 12 seconds ((70 rps−46 rps) / 2 rps / second = 12 seconds). Thus, the discharge pressure of the compressors 21a and 21b is reduced by reducing the rotational speed of the compressors 21a and 21b.

  The CPUs 110a and 110b determine whether or not an end condition for the second start control is satisfied when executing the second start control, and if the end condition for the second start control is satisfied Then, the second activation control is terminated, and the process proceeds to the third activation control described next. The end condition of the second activation control is, for example, whether or not a predetermined time has elapsed since the start of the second activation control. This predetermined time is determined in advance in consideration of the time required to reduce the rotational speed of the compressors 21a and 21b to the lower limit rotational speed of 20 rps. For example, a predetermined ratio for reducing the rotational speed is In the case of 2 rps / 1 second as described above, (70 rps-20 rps) / 2 rps = 25 seconds.

  Accordingly, when the time taken to reduce the rotational speed of the compressors 21a, 21b to the rotational speed X corresponding to the outside air temperature T is shorter than the predetermined time (for example, 25 seconds), the CPUs 110a, 110b , 21b is reduced to the rotational speed X, and the compressors 21a and 21b are driven while maintaining the rotational speed X until a predetermined time. For example, as described above, when the outside air temperature T is 0 ° C., the rotational speed X is 46 rps, and it takes 12 seconds to decrease to this rotational speed. Therefore, the CPUs 110a and 110b have the compressor 21a, 21b is driven at 46 rps. When the outside air temperature T is “−10 ° C. or lower”, the rotational speed X is “70 rps”, which is the same as the rotational speed at startup. In this case, the CPUs 110 a and 110 b maintain the compressors 21 a and 21 b at 70 rps. Then, it is driven for a predetermined time (25 seconds).

[Third start control]
The CPUs 110a and 110b start the third activation control following the second activation control. By executing the first activation control, the refrigerant stagnation state in the compressors 21a and 21b is eliminated to some extent, and the discharge amount of refrigerating machine oil that does not hinder the lubrication of the compressors 21a and 21b is obtained. Moreover, the discharge pressure of compressor 21a, 21b has fallen by performing 2nd starting control. In the third start-up control, various types for reducing the rise time of the air-conditioning operation capacity while reducing the refrigerant stagnation amount in the compressors 21a and 21b and not exceeding the upper limit value of the discharge pressure in the compressors 21a and 21b. Take control.

  Therefore, in the first startup control and the second startup control, the functions of the two outdoor heat exchangers are made different so that the evaporator and the condenser are mixed in the outdoor unit. When the mode is heating operation / heating-main operation, both of the outdoor heat exchangers function as an evaporator, and when the mode is cooling operation / cooling-main operation, both of the outdoor heat exchangers function as a condenser.

  Next, specific operations of the components of the outdoor units 2a and 2b when the third activation control is executed will be described. In the present embodiment, since the air conditioner 1 performs the heating operation, the CPU 110a and the CPU 110b perform the rotation speed control of the compressors 21a and 21b and the second outdoor heat exchanger 25a in the third activation control as illustrated in FIG. , 25b function switching (switching from condenser to evaporator. The first outdoor heat exchangers 24a and 24b are maintained as evaporators in the first startup control and the second startup control, and this state is maintained). Opening control of the outdoor expansion valves 40a, 40b and the second outdoor expansion valves 41a, 41b, and opening / closing control of the first electromagnetic valves 42a, 42b and the second electromagnetic valves 43a, 43b are performed.

  Among the above-described controls, items other than the rotational speed control of the compressors 21a and 21b are the same controls as the second start-up control in the first embodiment including the end condition, and thus the description thereof will be omitted. Next, the rotational speed control of the compressors 21a and 21b will be described in detail. The state of the refrigerant circuit of the air conditioner 1 when performing the third activation process is the same as that when performing the second activation control in the first embodiment, that is, the state shown in FIG.

  When starting the third start-up control, the CPUs 110a and 110b perform control to return the rotational speed of the compressors 21a and 21b to 70 rps, which is the rotational speed at startup. Specifically, the CPUs 110a and 110b gradually increase the rotation speed of the compressors 21a and 21b to 70 rps at a predetermined rate, and after the rotation speed reaches 70 rps, the rotation is continued until the third start control is finished. The compressors 21a and 21b are driven while maintaining the number (70 rps).

  Here, the predetermined ratio of increasing the rotation speed of the compressors 21a and 21b does not exceed the upper limit value of the discharge pressure in the compressors 21a and 21b by rapidly increasing the rotation speed of the compressors 21a and 21b. It is determined as follows. For example, the predetermined rate for increasing the rotation speed of the compressors 21a and 21b is 10 rps / 30 seconds, the outside air temperature T is 7 ° C. in the second start-up control, and the rotation speed of the compressors 21a and 21b is set to the outside air temperature If the rotational speed X corresponding to T is reduced to 30 rps, the time taken for the compressors 21a and 21b to increase from 30 rps to 70 rps is ((70 rps-30 rps) / 10 rps) × 30 Second = 120 seconds.

  As described above, by gradually increasing the rotation speed of the compressors 21a and 21b to 70 rps, the upper limit value of the discharge pressure in the compressors 21a and 21b is not exceeded. As described above, the end condition of the third start control is the same as the end condition of the second start control in the first embodiment. If the end condition of the third start control is satisfied, the CPU 110a, 110b complete | finishes starting control of the air conditioning apparatus 1, and transfers to normal air-conditioning control.

  Next, the flow of processing in the air-conditioning apparatus 1 in the present embodiment will be described using the flowchart shown in FIG. The flowchart shown in FIG. 9 shows the flow of processing related to the first activation control, the second activation control, and the third activation control that is performed when the air conditioner 1 is activated, and ST represents a step and is a number that follows this step. Represents a step number. In FIG. 9, the processing related to the present invention is mainly described, and other general processing such as control of the refrigerant circuit corresponding to the operating conditions such as the set temperature and the air volume instructed by the user is described. Is omitted. In addition, since the processes related to the first activation control, the second activation control, and the third activation control performed by the CPUs 110a and 110b are the same, in the following description, the first activation performed by the CPU 110a provided in the control unit 100a of the outdoor unit 2a. Processing related to control, second activation control, and third activation control will be described.

  Receiving the operation start instruction, the CPU 110a determines whether or not the start condition for the first activation control is satisfied (ST21). If the start condition of the first activation control is satisfied (ST21-Yes), the CPU 110a controls the first three-way valve 22a so that the first outdoor heat exchanger 24a functions as an evaporator, and the second outdoor heat. The second three-way valve 23a is controlled so that the exchanger 25a functions as an evaporator (ST22).

  Next, the CPU 110a controls to start the compressor 21a at the starting rotational speed or to continue driving at the starting rotational speed (ST23).

  Next, the CPU 110a controls the opening degree of the first outdoor expansion valve 40a according to the refrigerant superheat degree at the refrigerant outlet of the first outdoor heat exchanger 24a, and fully opens the second outdoor expansion valve 41a (ST24). .

  Next, the CPU 110a opens the first electromagnetic valve 42a (ST25) and puts the refrigerant in the hot gas bypass 36a. As described in the first embodiment, the second electromagnetic valve 43a has been opened since the outdoor unit 2a is stopped, and the CPU 110a maintains this state so that the refrigerant flows through the oil return pipe 37a. .

  Next, CPU 110a determines whether or not an end condition for the first activation control is satisfied (ST26). If the termination condition for the first activation control is not satisfied (ST26-No), the CPU 110a returns the process to ST22 and continues the first activation control.

  If the termination condition of the first activation control is satisfied (ST26-Yes), the CPU 110a terminates the first activation process and proceeds to the second activation process. The CPU 110a takes in the last stored outside air temperature T from the storage unit 120a out of the outside temperature detected by the outside temperature sensor 58a and stored in the storage unit 120a (ST27).

  Next, the CPU 110a determines whether or not the taken-in outside air temperature T is −10 ° C. or lower (ST28). If the outside air temperature T is −10 ° C. or lower (ST28—Yes), there is no need to reduce the rotational speed of the compressor 21a (see the rotational speed table 200 in FIG. 8), so the CPU 110a advances the process to ST31.

  If the outside air temperature T is not −10 ° C. or lower (ST28-No), the CPU 110a refers to the rotation speed table 200 stored in the storage unit 120a and extracts the rotation speed X corresponding to the taken-in outside air temperature T. (ST29). Then, the CPU 110a reduces the rotational speed of the compressor 21a to the extracted rotational speed X (ST30).

  Next, CPU 110a determines whether or not an end condition for the second activation control is satisfied (ST31). If the end condition of the second activation control is not satisfied (ST31-No), the CPU 110a returns the process to ST27.

  If the termination condition for the second activation control is satisfied (ST31-Yes), the CPU 110a terminates the second activation control and shifts to the third activation control. CPU 110a determines whether the operation mode instructed by the user is a heating operation or a heating main operation (ST32).

  If the operation mode is the heating operation or the heating-main operation (ST32-Yes), the CPU 110a switches the second outdoor heat exchanger 25a functioning as a condenser to function as an evaporator (ST33). Next, the CPU 110a controls the opening degree of the first outdoor expansion valve 40a in accordance with the degree of refrigerant superheating at the refrigerant outlet of the first outdoor heat exchanger 24a, and the opening degree of the second outdoor expansion valve 41a in the second outdoor area. Control is performed according to the degree of refrigerant superheat at the refrigerant outlet of the heat exchanger 25a (ST34). Next, the CPU 110a returns the rotational speed of the compressor 21a to the starting rotational speed and drives the compressor 21a (ST35).

  Next, the CPU 110a starts a timer after the end of the second activation control, and determines whether or not a predetermined time, for example, 2 minutes has elapsed since the end of the second activation control (ST36). If the predetermined time has not elapsed since the end of the second activation control (ST36-No), the CPU 110a returns the process to ST32.

  If the predetermined time has elapsed from the end of the second activation control (ST36-Yes), the CPU 110a closes the first electromagnetic valve 42a and the second electromagnetic valve 43a (ST37), and the hot gas bypass pipe 36a and the oil return pipe The refrigerant is prevented from flowing through 37a.

  Next, CPU 110a determines whether or not an end condition for the third activation control is satisfied (ST38). If the end condition of the third start control is not satisfied (ST38-No), the CPU 110a continuously drives the compressor 21a at the start rotation speed (ST41), returns the process to ST38, and performs the third start control. Continue. If the termination condition of the third activation control is satisfied (ST38-Yes), the CPU 110a terminates the third activation control, that is, terminates the activation control of the air conditioner 1, and starts normal air conditioning control.

  If the start condition for the first activation control is not satisfied in ST21 (ST21-No), the CPU 110a starts the normal air conditioning control without performing the activation control.

  In ST32, if the operation mode is not the heating operation or the heating main operation (ST32-No), the operation mode instructed by the user is the cooling operation or the cooling main operation. Therefore, the CPU 110a functions as an evaporator. The first outdoor heat exchanger 24a is switched to function as a condenser (ST39). Next, the CPU 110a fully opens the opening degree of the first outdoor expansion valve 40a or controls it according to the degree of refrigerant subcooling at the refrigerant outlet of the first outdoor heat exchanger 24a, and opens the second outdoor expansion valve 41a. The degree is fully opened or controlled according to the degree of refrigerant supercooling at the refrigerant outlet of the second outdoor heat exchanger 25a (ST40). Then, CPU 110a advances the process to ST35.

  In the embodiment described above, the case where the second start control is performed for a predetermined time and then the third start control is shifted to has been described. However, in the second start control, the rotation speed of the compressors 21a and 21b is reduced to reduce the outside air temperature T. If the rotational speed X corresponding to is reached, it may be controlled to immediately shift to the third activation control. For example, as described above, it takes 12 seconds to reduce the compressors 21a and 21b to 46 rps. It may stop in seconds and immediately shift to the third activation control. When the outside air temperature T is −10 ° C. or lower and there is no need to reduce the rotational speed of the compressors 21a and 21b (when maintaining the rotational speed at startup, 70 rps), the CPUs 110a and 110b perform the second startup control The third activation control may be performed immediately after the first activation control is stopped without performing the above.

  As described above, according to the air conditioner of the present invention, in order to quickly eliminate the refrigerant stagnation state of the compressor, even if the compressor is continuously driven at a predetermined rotational speed, An increase in the discharge side (high pressure side) pressure of the compressor is suppressed by causing the refrigerant to flow through at least one of the tubes. Thereby, since the pressure rise inside a compressor can be suppressed, generation | occurrence | production of the refrigerant | coolant stagnation resulting from the pressure rise inside a compressor can be suppressed.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2a, 2b Outdoor unit 6a-6e Splitting unit 8a-8e Indoor unit 13a-13c Suction port 21a, 21b Compressor 22a, 22b First three-way valve 23a, 23b Second three-way valve 24a, 24b First outdoor heat Exchanger 25a, 25b Second outdoor heat exchanger 26a, 26b Outdoor fan 27a, 27b Accumulator 28a, 28b Oil separator 36a, 36b Hot gas bypass pipe 37a, 37b Oil return pipe 40a, 40b First outdoor expansion valve 41a, 41b First Two outdoor expansion valves 42a, 42b First electromagnetic valve 43a, 43b Second electromagnetic valve 50a, 50b High pressure sensor 51a, 51b Low pressure sensor 53a, 53b Discharge temperature sensor 54a, 54b Suction temperature sensor 56a, 56b First heat exchange temperature sensor 57a 57b Second heat exchange temperature sensor 58a 58b outside air temperature sensor 61a~61e solenoid valve 62a~62e solenoid valve 63a~63e first distribution pipe 64a~64e second distribution pipe 81a~81e indoor heat exchanger 82a~82e indoor expansion valves 100a, 100b control means 110a, 110b CPU
200 rpm table

Claims (4)

At least one compressor, an oil separator, at least two outdoor heat exchangers, and the outdoor connected to one end of each of the outdoor heat exchangers to the refrigerant discharge port or the refrigerant suction port of the compressor A flow path switching means for switching the connection of the heat exchanger, an outdoor expansion valve connected to the other end of each of the outdoor heat exchangers for adjusting the refrigerant flow rate in the outdoor heat exchanger, and the flow path switching valve. At least one outdoor unit provided with control means for performing switching control and opening degree control of the outdoor expansion valve;
An indoor unit connected to the outdoor unit by at least two refrigerant pipes;
An air conditioner comprising:
The outdoor unit has a first solenoid valve, and has a hot gas bypass pipe and / or a second solenoid valve for connecting a high-pressure refrigerant pipe on the discharge side and a low-pressure refrigerant pipe on the suction side of the compressor. And an oil return pipe connecting the suction side of the compressor,
The control means opens at least one of the first solenoid valve and the second solenoid valve if the first predetermined condition is satisfied when the outdoor unit is activated, and the compressor is predetermined. If the first start control that is driven at a predetermined number of revolutions is performed , and the second predetermined condition is satisfied while the first start control is being performed, the first start control is opened following the first start control. Further, the first solenoid valve and / or the second solenoid valve is maintained in a state where the first solenoid valve is opened for a predetermined time from the end of the first startup control, and the rotation speed is the same as when the compressor is subjected to the first startup control. The air conditioner is characterized by performing second start-up control that is continuously driven .   The control means is configured to perform the first activation control so that one or a plurality of the outdoor heat exchangers among the plurality of the outdoor heat exchangers function as an evaporator. And the flow path switching corresponding to the outdoor heat exchanger so that at least one outdoor heat exchanger other than the one functioning as an evaporator functions as a condenser. The air conditioner according to claim 1, wherein the valve is controlled. At least one compressor, an oil separator, at least two outdoor heat exchangers, and the outdoor connected to one end of each of the outdoor heat exchangers to the refrigerant discharge port or the refrigerant suction port of the compressor Flow path switching means for switching the connection of the heat exchanger, an outdoor expansion valve that is connected to the other end of each of the outdoor heat exchangers and adjusts the refrigerant flow rate in the outdoor heat exchanger, and outside air that detects the outside air temperature At least one outdoor unit comprising temperature detection means and control means for performing switching control of the flow path switching valve and opening degree control of the outdoor expansion valve;
An indoor unit connected to the outdoor unit by at least two refrigerant pipes;
An air conditioner comprising:
The outdoor unit has a first solenoid valve, and has a hot gas bypass pipe and / or a second solenoid valve for connecting a high-pressure refrigerant pipe on the discharge side and a low-pressure refrigerant pipe on the suction side of the compressor. And an oil return pipe connecting the suction side of the compressor,
If the first predetermined condition is satisfied when starting the outdoor unit, the control means performs start control including first start control, second start control, and third start control,
The first activation control is to open at least one of the first electromagnetic valve or the second electromagnetic valve and drive the compressor at a predetermined number of revolutions,
The second start-up control is executed subsequent to the first start-up control, and depends on the outside air temperature detected by the outside air temperature detecting means from the predetermined rotation speed in the first start-up control. Is driven down to a predetermined number of revolutions,
The third start-up control is executed subsequent to the second start-up control and corresponds to each of the outdoor heat exchangers so that all the outdoor heat exchangers to be used function as a condenser or an evaporator. Controlling the flow path switching valve, and driving the compressor back to the rotational speed in the first activation control.
  An air conditioner characterized by that. The control means is configured to perform the first activation control so that one or a plurality of the outdoor heat exchangers among the plurality of the outdoor heat exchangers function as an evaporator. And the flow path switching corresponding to the outdoor heat exchanger so that at least one outdoor heat exchanger other than the one functioning as an evaporator functions as a condenser. The air conditioning apparatus according to claim 3, wherein the valve is controlled.

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