JP2013024518A - Condensing unit set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a compressor against the load of operation in an insufficient refrigerant state by avoiding a deficiency of a refrigerant in each heat source unit of a condensing unit set which merges and uses refrigerant supplied from a plurality of heat source units for a refrigeration cycle.SOLUTION: In the condensing unit set which merges and uses the refrigerant supplied from the plurality of heat source units for the refrigeration cycle, each heat source unit includes a determination part which includes an outdoor heat exchanger, a compressing mechanism, a fan mechanism part, and a high-pressure sensor unit detecting high pressure of a high-pressure refrigerant discharged from the compressing mechanism. The condensing unit set includes a determination part which determines a heat source unit whose high pressure is higher than those of other heat source units, a state discrimination part which discriminates a heat source unit in an insufficient refrigerant state, and a control part which drives and controls the fan mechanism part of the heat source unit discriminated to have higher high pressure than any other heat source unit and to be in the insufficient refrigerant state to increase the rotating speed of the fan.

Description

  The present invention relates to a condensing unit set in which refrigerants supplied from a plurality of heat source units are used in combination, and more particularly, to drive control when a heat source unit that is short of refrigerant occurs.

  2. Description of the Related Art Conventionally, a so-called multi-outdoor unit type air conditioner including a condensing unit set that joins refrigerants supplied from a plurality of heat source units (outdoor units) and uses them for air conditioning is known (Patent Documents below). 1). In this condensing unit set, the refrigerant sent from the indoor unit (indoor unit) side is divided and sent to each of the plurality of heat source units, and the heat supplied by each heat source unit is merged and the refrigerant supplied from each is joined. Is circulated to the indoor unit side for air conditioning.

JP 2007-107860 A

  In the above condensing unit set, for example, during the cooling operation (refrigeration cycle), a phenomenon in which the amount of refrigerant circulating in each heat source unit varies depending on the pressure difference between the heat source units of the high-pressure refrigerant discharged from the compressor. Arise. For example, the liquefied refrigerant is biased and accumulated in the heat source unit where the pressure of the high-pressure refrigerant is low, and the heat source unit where the pressure of the high-pressure refrigerant is high is insufficient. Thus, when the refrigerant is insufficient in the heat source unit having a high pressure of the high-pressure refrigerant and is in a so-called out-of-gas state, the heat-source unit in the out-of-gas state cannot obtain sufficient air-conditioning performance due to the lack of the refrigerant, and is compressed. The machine is also burdened.

  The present invention has been made to solve the above-described problem, and in a condensing unit set used in a refrigeration cycle by combining refrigerants supplied from a plurality of heat source units, the occurrence of refrigerant shortage in each heat source unit is avoided. And it aims at protecting a compressor from the burden by the driving | running in the said refrigerant | coolant shortage state.

The condensing unit set of the present invention includes a plurality of heat source units (2a to 2c), and condensing unit sets (2) that join the refrigerants supplied from the plurality of heat source units (2a to 2c) and use them in the refrigeration cycle. ) And
Each of the plurality of heat source units (2a to 2c)
A heat exchanger (25);
A compressor (21) for discharging a high-pressure refrigerant toward the heat exchanger (25);
A fan mechanism (28) for supplying air used for heat exchange to the heat exchanger (25) by rotation of the fan;
A high pressure detector (201) for detecting the high pressure of the high pressure refrigerant discharged from the compressor (21),
As a control unit (200) that performs drive control of the plurality of heat source units (2a to 2c),
Each of the heat source units (2a to 2c) receives each of the high pressures output from the high pressure detector (201), and determines whether the high pressure is higher than the high pressures of the other heat source units A determination unit (210) to perform,
A state discriminating unit (220) for discriminating among the plurality of heat source units (2a to 2c) a heat source unit (2a to 2c) that is in a refrigerant shortage state;
Regarding the heat source unit that has been determined by the determination unit (210) that the high pressure is higher than the high pressure of another heat source unit and that has been determined to be in a refrigerant shortage state by the state determination unit (220), And a controller (230) that drives and controls the fan mechanism (28) of the heat source units (2a to 2c) to increase the rotational speed of the fan.

  In the configuration of the present invention, the control unit (230) determines that the high pressure is higher than the high pressures of the other heat source units by the determination unit (210), and the state determination unit (220) is in a refrigerant shortage state. For the heat source unit determined to be, the fan mechanism (28) of the heat source unit in the refrigerant shortage state is driven and controlled to increase the rotation speed of the fan, so that the heat exchanger (25) has a condensing capacity in the heat source unit. The amount of refrigerant that is circulated and drawn into the heat source unit increases. For this reason, even if a difference in high pressure occurs between the plurality of heat source units (2a to 2c) and the refrigerant is concentrated in the heat source unit having a low high pressure, the heat source unit having a high high pressure. By drawing the refrigerant to the side, it is possible to eliminate the shortage of refrigerant in the heat source unit having a high high-pressure pressure, and it is possible to protect the compressor (21) from the burden caused by the operation in the refrigerant shortage state.

  Further, in the condensing unit set, each of the plurality of heat source units (2a to 2c) may pass a part of the refrigerant that has passed through the economizer heat exchanger (271) to the low pressure side of the compressor (21). An intermediate injection circuit (27) that returns to the intermediate injection section that is the middle of the high-pressure side, and a refrigerant temperature detection section that detects the temperature of the refrigerant after passing through the heat exchanger (25) and the economizer heat exchanger (271) (203), wherein the state determination unit (220) includes the refrigerant temperature output from the refrigerant temperature detection unit (203) and the high pressure pressure output from the high pressure detection unit (201). When the subcool represented by the temperature difference from the saturation temperature determined by the value reaches a predetermined value, or when the refrigerant temperature detector (203 When the difference between the subcool in the heat source unit including the high pressure detection unit (201) and the subcool in the other heat source units (2a to 2c) reaches a predetermined value, the refrigerant temperature detection unit (203 ) And the high pressure detector (201) are preferably determined to be in a refrigerant shortage state.

  Further, in the condensing unit set, each of the plurality of heat source units (2a to 2c) may pass a part of the refrigerant that has passed through the economizer heat exchanger (271) to the low pressure side of the compressor (21). An intermediate injection circuit (27) that returns to the intermediate injection section that is the middle of the high-pressure side, an on-off valve (272) that adjusts the amount of refrigerant from the intermediate injection circuit (27) toward the compressor (21), and the on-off valve An opening / closing valve control unit (240) for controlling the opening degree of the opening / closing valve, and the state determination unit (220) is configured so that the opening degree of the opening / closing valve (272) output from the opening / closing valve control unit (240) is in advance. When the set value is reached, it is preferable to determine that the heat source unit including the on-off valve (272) is in a refrigerant shortage state.

  In the condensing unit set, each of the plurality of heat source units (2a to 2c) includes a high-pressure temperature detection unit (202) that detects the temperature of the high-pressure refrigerant discharged from the compressor (21). The state determination unit (220) includes the high-pressure temperature detection unit (202) when the discharge pipe temperature output from the high-pressure temperature detection unit (202) reaches a predetermined temperature. It is preferable to determine that the heat source unit is in a refrigerant shortage state.

  In these configurations, the state determination unit (220) has the temperature of the refrigerant that has passed through the economizer heat exchanger (271) of the intermediate injection circuit (27) and the high-pressure refrigerant output from the high-pressure detection unit (201). Since it is determined whether the heat source unit is in a refrigerant shortage state based on the high pressure, it is possible to accurately determine whether the refrigerant is insufficient.

  In the condensing unit set, the control unit (230) determines that the high pressure is higher than the high pressures of other heat source units by the determination unit (210), and the state determination unit ( For the heat source unit determined to be in a refrigerant shortage state by 220), it is preferable to further drive-control the compressor (21) of the heat source unit to lower its compression capacity.

  In this configuration, the control unit (230) decreases the compression capacity of the compressor (21) of the heat source unit that is in a refrigerant shortage state, and thus reduces the compression capacity of the compressor (21) of the heat source unit that is in a refrigerant shortage state. Compared with before the control, the ratio of the amount of refrigerant circulated by other heat source units to the amount of refrigerant circulated by the heat source unit in the refrigerant shortage state becomes high, that is, the amount of refrigerant drawn into the heat source unit. The amount increases. For this reason, the refrigerant | coolant circulation amount in each heat source unit can be approached uniformly, and the situation where the liquefied refrigerant | coolant concentrates on some heat source units and accumulates can be eliminated.

  In the condensing unit set, the control unit (230) determines that the high pressure is higher than the high pressures of other heat source units by the determination unit (210), and the state determination unit ( 220), when there is a heat source unit that is determined to be in a refrigerant shortage state, the compressor (21) of the heat source unit that is determined not to be in a refrigerant shortage state by the state determination unit (220) is further driven and controlled. It is preferable to increase the compression capacity.

  In this configuration, the controller (230) increases the compression capacity of the compressor (21) of the heat source unit in which the refrigerant is accumulated rather than the heat source unit that is not in the refrigerant shortage state, that is, the heat source unit in the refrigerant shortage state. The refrigerant accumulated in the heat source unit is discharged. As a result, the refrigerant circulation amount in each heat source unit can be made uniform, and the situation where the liquefied refrigerant is biased and accumulated in some heat source units can be solved.

  According to the present invention, in the condensing unit set used for the refrigeration cycle by combining refrigerants supplied from a plurality of heat source units, the occurrence of refrigerant shortage in each heat source unit is avoided, and the burden due to operation in the refrigerant shortage state Can protect the compressor from.

It is the schematic of the refrigerant circuit of the freezing apparatus provided with the condensing unit set which concerns on one Embodiment of this invention. It is a figure which shows schematic structure of a several heat-source unit. It is a block diagram which shows schematic structure of the control system and main mechanism of a freezing apparatus. It is a flowchart which shows the control at the time of refrigerant | coolant shortage generation | occurrence | production by a freezing apparatus. It is a flowchart which shows the drive control of the heat-source unit at the time of a refrigerant | coolant shortage. It is a flowchart which shows the further drive control about a heat-source unit.

  Hereinafter, a condensing unit set according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1: shows the schematic of the refrigerant circuit of the freezing apparatus provided with the condensing unit set which concerns on one Embodiment of this invention.

  The refrigeration apparatus 1 is used for product cooling in a refrigerated product or a store of frozen products, and is a condensing unit including a plurality (three in this embodiment) of air-cooling heat source units 2a to 2c. A set 2 and a plurality (two in this embodiment) of indoor units 3a and 3b are provided. The heat source units 2a to 2c and the indoor units 3a and 3b, which are use side units, are connected by a liquid side pipe 4 and a gas side pipe 5. The indoor units 3a and 3b may be used for any of a showcase installed in a supermarket, a refrigerator, a freezer, and an indoor unit in an air conditioner.

  The refrigeration apparatus 1 once merges the refrigerants that are heat-exchanged in the indoor units 3a and 3b and discharged from the indoor units 3a and 3b, and divides and sends the refrigerants to the plurality of heat source units 2a to 2c. A refrigeration cycle is performed in which the heat exchanged refrigerants combined from the refrigerants are combined and returned to the indoor units 3a and 3b. One of the heat source units 2a, 2b, 2c provided in the condensing unit set 2 functions as a master unit (details will be described later). In the present embodiment, the master unit will be described as the heat source unit 2a.

  The indoor units 3a and 3b are mainly composed of indoor expansion valves 31a and 31b, indoor heat exchangers 32a and 32b, and pipes connecting them. In the present embodiment, the indoor expansion valves 31a and 31b are connected to the liquid side piping 4 side (hereinafter referred to as the liquid side) of the indoor heat exchangers 32a and 32b in order to adjust the refrigerant pressure and the refrigerant flow rate. This is an electric expansion valve. In the present embodiment, the indoor heat exchangers 32a and 32b are cross fin tube heat exchangers, and exchange heat with indoor air. In the present embodiment, the indoor units 3a and 3b include an indoor fan (not shown) for taking in and sending out indoor air into the indoor unit, and the indoor air and the indoor heat exchangers 32a and 32b are provided. Heat exchange is performed with the flowing refrigerant.

  FIG. 2 is a diagram showing a schematic configuration of the heat source units 2a to 2c. Since the heat source units 2a to 2c have the same configuration, the heat source unit 2a will be described below as an example. The refrigeration apparatus 1 will be described in addition to FIG.

  The heat source unit 2a includes a refrigerant circuit 20 that circulates refrigerant between the indoor units 3a and 3b, a variable capacity compressor 22 of variable capacity type, and a plurality (two in the present embodiment) of constant capacity. And a constant capacity compressor 23, 24 of the type, and a compression mechanism of the refrigerant is performed by the compression mechanism 21.

  The variable capacity compressor 22 is a variable capacity compressor whose capacity is changed by inverter control and compresses sucked refrigerant. The constant capacity compressors 23 and 24 are compressors that compress the sucked refrigerant gas with a constant compression capacity.

  In addition, the heat source unit 2 a includes an outdoor heat exchanger 25, a receiver 26, an intermediate injection circuit 27, and a fan mechanism unit 28 in the refrigerant circuit 20.

  The fan mechanism unit 28 takes ambient air into the heat source unit 2 a and sends it to the outdoor heat exchanger 25. The fan mechanism 28 changes the amount of air sent to the outdoor heat exchanger 25 by controlling the rotation speed of a fan motor, which will be described later. In the present embodiment, the outdoor heat exchanger 25 is a cross fin tube type heat exchanger, and heat is generated between the air sent by the fan mechanism 28 and the refrigerant flowing in the outdoor heat exchanger 25. Exchanged.

  The liquid side pipe 4 connects the liquid side of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b and the liquid side of the outdoor heat exchanger of the heat source units 2a to 2c. The gas side pipe 5 connects the gas side of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b and the compression mechanism of the heat source units 2a to 2c.

  A refrigerant pipe on the discharge side of the compression mechanism 21 is provided with a high-pressure sensor 201 that detects the pressure of the high-pressure refrigerant compressed by the compression mechanism 21 and a high-pressure sensor 202 that detects the temperature of the high-pressure refrigerant. . In the present embodiment, the high-pressure temperature sensor 202 is provided in the discharge pipe of each compressor 22, 23, 24.

  Furthermore, oil separators 221, 231, and 241 are provided on the discharge sides of the compressors 22, 23, and 24, respectively, and the refrigerant that has passed through these oil separators 221, 231, and 241 is merged to be an outdoor heat exchanger. 25.

  The receiver 26 provided on the downstream side of the outdoor heat exchanger 25 stores the refrigerant compressed by the compression mechanism 21 and condensed in the outdoor heat exchanger 25. The receiver 26 temporarily stores the refrigerant in order to adjust the flow rate of the refrigerant flowing through the refrigerant circuit 20 according to the cooling load.

  An intermediate injection circuit 27 is provided on the downstream side of the receiver 26. The intermediate injection circuit 27 exchanges heat between the refrigerant flowing through the refrigerant circuit 20 and the refrigerant flowing through the branch circuit 20a branched from the refrigerant circuit 20, and is a refrigerant flowing through the branch circuit 20a. The subsequent refrigerant is returned to the intermediate injection section that is intermediate between the low pressure side and the high pressure side of each compressor 22, 23, 24.

  The intermediate injection circuit 27 includes an economizer heat exchanger 271 and an electric expansion valve 272. The economizer heat exchanger 271 performs the heat exchange between the refrigerant flowing through the refrigerant circuit 20 and the refrigerant flowing through the branch circuit 20 a branched from the refrigerant circuit 20. The electric expansion valve (open / close valve) 272 is provided on the upstream side of the economizer heat exchanger 271 in the branch circuit 20a. The electric expansion valve 272 is a valve capable of adjusting the opening degree of the branch circuit 20a. By changing the opening degree, the electric expansion valve 272 is subjected to heat exchange by the economizer heat exchanger 271 to the intermediate injection portion of each compressor 22, 23, 24. Expand the returning refrigerant. The electric expansion valve 272 is driven and controlled to an opening degree corresponding to the cooling load by an outdoor side control unit 200 described later.

  Between the branch circuit 20a and the intermediate injection parts of the compressors 22, 23, 24, there are provided an electric valve 222 whose opening degree can be adjusted and electromagnetic valves 232, 242 that perform opening and closing operations. These motor-operated valve 222 and electromagnetic valves 232 and 242 control whether or not the refrigerant is returned from the intermediate injection circuit 27 to each of the compressors 2, 23 and 24, and control for changing the amount of refrigerant. In the present embodiment, an example is shown in which a circuit 20b that returns to the discharge side of each of the compressors 22, 23, and 24 is used as a part of the refrigerant from the intermediate injection circuit 27. Further, a liquid backflow prevention valve 29 is provided downstream of the branch point of the branch circuit 20 a in the refrigerant circuit 20, and further, a refrigerant that returns the refrigerant to the receiver 26 downstream of the liquid backflow prevention variable valve 29. A pipe 20c is provided.

  Further, for example, a refrigerant temperature sensor 203 for detecting the temperature of the refrigerant flowing through the point is provided downstream of the branch point of the branch circuit 20a in the refrigerant circuit 20.

  Next, the operation of the refrigeration apparatus 1 will be described. During operation of the refrigeration apparatus 1, the refrigerant circulates while changing phase in the refrigerant circuit 20 to perform a vapor compression refrigeration cycle.

  During the refrigeration cycle, the refrigerant compressed by the compression mechanism 21 of each heat source unit 2a, 2b, 2c provided in the condensing unit set 2 is merged after passing through the discharge pipe from each. The discharged refrigerant merged flows into the outdoor heat exchanger 25. In the outdoor heat exchanger 25, heat is exchanged with the air supplied by the fan mechanism 28, and the refrigerant dissipates heat to the outdoor air and condenses. Thereafter, the refrigerant condensed in the outdoor heat exchanger 25 is temporarily stored by the receiver 26 according to the cooling load. Thereby, the flow volume of the refrigerant | coolant which flows through the refrigerant circuit 20 is adjusted according to cooling load. The refrigerant passing through the receiver 26 is supercooled by the economizer heat exchanger 271 of the intermediate injection circuit 27, and the refrigerant is sent from the liquid side pipe 4 to the indoor units 3a and 3b. A part of the refrigerant flowing through the refrigerant circuit 20 passes through the economizer heat exchanger 271, and then returns to the intermediate injection portion of each compressor 22, 23, 24 by the circuit 20b.

  The refrigerant circulated from the liquid side pipe 4 to the indoor units 3a and 3b is sent to the indoor heat exchangers 32a and 32b. The indoor expansion valves 31a and 31b are adjusted to a predetermined opening degree by the control unit 230 of the outdoor side control unit 200 described later. At this time, in the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b, the refrigerant absorbs heat from the indoor air and evaporates. That is, the refrigerant introduced into the indoor units 3a and 3b evaporates in the indoor heat exchangers 32a and 32b, and as a result, the indoor air is cooled.

  The refrigerant evaporated by the indoor heat exchangers 32 a and 32 b and discharged from each of them merges and flows into the heat source units 2 a, 2 b and 2 c through the gas side pipe 5. Thereafter, the refrigerant is sucked into the compressors 22, 23 and 24. The compressors 22, 23, and 24 compress the sucked refrigerant and discharge it again. In the refrigerant circuit 20, such circulation of the refrigerant is repeated.

  FIG. 3 is a block diagram showing a schematic configuration of the control system and main mechanisms of the refrigeration apparatus 1.

  Each of the heat source units 2a, 2b, and 2c includes an outdoor control unit (an example of a control unit in the claims) 200. In each heat source unit 2a, 2b, 2c, the outdoor control unit 200 includes an inverter control circuit 225 for driving the compressor provided in each heat source unit 2a, 2b, 2c, a drive control circuit 235, 245, a high pressure A temperature sensor 202, a refrigerant temperature sensor 203, a high-pressure sensor 201, a fan mechanism 28, and an electric expansion valve 272 are connected.

  The outdoor control unit 200 includes a microcomputer, a memory, and the like, and controls operation of each operation mechanism provided in the heat source unit. The outdoor side control part 200 transmits / receives a control signal etc. via the transmission line 8 between the indoor side control parts 300 of indoor unit 3a, 3b, for example.

  The inverter control circuit 225 appropriately changes the drive frequency (Hz) of the variable capacity compressor 22 of the inverter control system, and drives the compressor 22 by changing the compression capacity. The drive control circuit 235 drives and controls the compressor 23 having a constant compression capacity, and the drive control circuit 245 is a control circuit that drives and controls the compressor 24 having a constant compression capacity.

  A high-pressure sensor (an example of a high-pressure detector in the claims) 201 is a refrigerant compressed by the compression mechanism 21 (in this embodiment, a refrigerant joined after discharge from the compressors 22, 23, and 24). Is output to the outdoor control unit 200. The outdoor control unit 200 of the heat source unit 2a that is the master unit stores the high pressure, and the outdoor control unit 200 of the heat source units 2b and 2c that are the slave units directs the high pressure to the heat source unit 2a of the master unit. Send it out.

  A high-pressure temperature sensor (an example of a high-pressure temperature detection unit in the claims) 202 indicates a high-pressure refrigerant temperature of refrigerant compressed by the compression mechanism 21 (that is, refrigerant discharged from the compressors 22, 23, and 24). Output to the outdoor control unit 200. A refrigerant temperature sensor (an example of a refrigerant temperature detection unit in the claims) 203 outputs the temperature of the refrigerant after passing through the intermediate injection circuit 27 to the outdoor control unit 200. The outdoor control unit 200 of the heat source unit 2a that is the master unit stores the values of the respective temperatures and pressures, and the outdoor control unit 200 of the heat source units 2b and 2c that are the slave units stores the values of the respective temperatures and pressures. It sends out toward the heat source unit 2a of the machine.

  The electric expansion valve 272 expands the refrigerant flowing through the branch circuit 20a in the intermediate injection circuit 27, but the opening degree changing operation is driven and controlled by the outdoor side control unit 200 according to the cooling load.

  The fan mechanism unit 28 that sends air to the outdoor heat exchanger 25 is also connected to the outdoor side control unit 200 and is driven and controlled by the outdoor side control unit 200. The fan mechanism unit 28 includes a fan 282 and a fan drive mechanism 281 including a fan motor that is a drive source of the fan and a drive control circuit for the fan motor.

  Each of the indoor units 3a and 3b includes an indoor side control unit 300 that controls each operation mechanism of the indoor unit. The indoor side control unit 300 includes a microcomputer, a memory, and the like, and is connected to the outdoor side control unit 200 through the transmission line 8. The indoor side control unit 300 transmits and receives control signals to and from the outdoor side control unit 200.

  One of the heat source units 2a, 2b, 2c provided in the condensing unit set 2 functions as a master unit. The heat source unit that is the master unit includes a determination unit 210, a state determination unit 220, an on-off valve control unit 240, and a control unit 230 in the outdoor control unit 200, as indicated by a broken line in FIG. Yes. When the heat source unit 2a, which is a parent device, is necessary according to the cooling load, the heat source units 2b and 2c are driven and controlled as child devices.

  The determination unit 210 acquires the high pressures output from the high pressure sensors 201 provided in the heat source units 2a, 2b, and 2c, and the high pressure is higher than the high pressures of the other heat source units. Determine the unit.

  The state discriminating unit 220 discriminates a heat source unit that is in a refrigerant shortage state among the heat source units 2a, 2b, and 2c. Details of the determination will be described later.

  The on / off valve control unit 240 controls the opening / closing operation of the electric expansion valve 272.

  The control unit 230 determines, for the heat source unit that is determined by the determination unit 210 that the high pressure is higher than the high pressure of the other heat source unit, and that the state determination unit 220 determines that the refrigerant is insufficient, The fan mechanism 28 is driven and controlled to increase the rotational speed of the fan.

  Next, the control when the refrigerant shortage occurs by the refrigeration apparatus 1 will be described. FIG. 4 is a flowchart showing the control performed by the refrigeration apparatus 1 when a refrigerant shortage occurs.

  Each of the heat source units 2a, 2b, 2c determines whether or not the outdoor control unit 200 has a flag = 1 indicating that it is set as a parent device in the built-in memory or the like (S1).

  When any one of the outdoor side control units 200 of each heat source unit 2a, 2b, 2c determines that flag = 1 is set in the built-in memory (YES in S1), it determines that it is the parent device. A heat source unit performs the process after S2. Here, a description will be given assuming that the master unit is the heat source unit 2a. The heat source unit that has determined that it is not the parent device ends the processing and stands by in preparation for an instruction from the heat source unit 2a that is the parent device.

  The determination unit 210 of the heat source unit 2a, which is the master unit, includes the high pressure from the high pressure sensor 201 of each of the heat source units 2a, 2b, and 2c (the refrigerant after compression by the compression mechanism 21 in each heat source unit). Pressure), and based on each of the high pressures, it is determined whether there is a heat source unit (whether the master unit or the slave unit) whose high pressure is higher than the high pressures of other heat source units. (S2). For example, when the high pressure detected by the high pressure sensor 201 of one heat source unit is higher than the high pressure of another heat source unit, the determination unit 210 selects the heat source unit having a high high pressure as It is determined as a heat source unit having a higher high pressure than other heat source units.

  When the determination unit 210 determines that there is a heat source unit in which the high pressure is higher than the high pressures of other heat source units (YES in S2), the state determination unit 220 of the master unit subsequently It is determined whether the high-pressure heat source unit is short of refrigerant (S3).

  The state determination unit 220 determines the refrigerant shortage state according to any of the following (1) to (3). Note that the state determination unit 220 may determine that only the heat source unit that satisfies a plurality of (1) to (3) is in a refrigerant shortage state.

  (1) The state determination unit 220 acquires the refrigerant temperature from the refrigerant temperature sensor 203 of the high-pressure heat source unit and the high-pressure pressure from the high-pressure sensor 201 of the heat source unit, and the refrigerant temperature and the high-pressure pressure When the temperature difference (subcool) from the saturation temperature of the refrigerant determined by the value reaches a predetermined value (for example, 10 ° C.), or between the subcool in the high-pressure heat source unit and the subcool in another unit When the difference reaches a predetermined value (for example, 10 ° C.), it is determined that the heat source unit having the high pressure is in a refrigerant shortage state.

  (2) The state determination unit 220 determines the opening degree of the electric expansion valve 272 output from the on-off valve control unit 240 of the high-pressure heat source unit as a predetermined value (a value that can be taken when there is a refrigerant shortage). When the value has reached a predetermined value (for example, 400 pls), it is determined that the high-pressure heat source unit is in a refrigerant shortage state.

  (3) The state discriminating unit 220 determines the average value of the temperature of the high-pressure refrigerant (discharge pipe temperature) output from the high-pressure temperature sensor 202 of the high-pressure heat source unit (when the refrigerant is insufficient). When the value reaches a predetermined value (for example, 110 ° C.), it is determined that the high-pressure heat source unit is in a refrigerant shortage state.

  In (3), the state determination unit 220 is not limited to the average value of the temperature (discharge pipe temperature) of the high-pressure refrigerant output from the high-pressure temperature sensor 202 of the high-pressure heat source unit. When all the discharge pipe temperatures output from the high-pressure temperature sensor 202 or at least one discharge pipe temperature has reached a predetermined temperature, the heat source unit at the high pressure is in a refrigerant shortage state. You may comprise so that it may be determined.

  When the state determination unit 220 determines that the high-pressure heat source unit is in a refrigerant shortage state (YES in S3), the control unit 230 of the heat source unit 2a that is the master unit is the high-pressure and refrigerant shortage heat source unit. The drive control process is started (S4).

  On the other hand, if there is no heat source unit having a higher pressure than the others in S2 (NO in S2), or if the high pressure heat source unit is not in a refrigerant shortage state in S3 (NO in S3). ) Finishes the process without performing the process at the time of the shortage of the refrigerant in S4, the outdoor side control unit 200 of the heat source unit 2a which is the parent machine.

  Next, drive control of the heat source unit when the refrigerant is insufficient will be described. FIG. 5 is a flowchart showing drive control of the heat source unit when the refrigerant is insufficient.

  As described above, when the heat source unit 2a, which is the master unit, determines that the high-pressure heat source unit is in a refrigerant shortage state, it starts drive control of the heat source unit when the refrigerant is short as shown in FIG.

  In the drive control of the heat source unit when the refrigerant is insufficient, the heat source unit 2a, which is the master unit, increases the air volume of the fan mechanism unit 28 according to the state of the high-pressure heat source unit, or the fan mechanism unit The process which stops the air volume increase of 28 is performed.

  In the drive control of the heat source unit when the refrigerant is insufficient, the control unit 230 of the heat source unit 2a that is the master unit first controls to increase the air volume of the fan mechanism unit 28 with respect to the high-pressure heat source unit. It is determined whether or not (S11).

  When the control unit 230 has not performed control to increase the air volume of the fan mechanism unit 28 with respect to the high-pressure heat source unit (YES in S11), the control unit 230 provides a drive circuit for the fan mechanism unit 28 of the heat source unit. Then, the rotational speed of the fan motor is gradually increased at a predetermined increase rate (for example, about 10%) (S12). That is, the control unit 230 increases the amount of air supplied from the fan mechanism unit 28 to the outdoor heat exchanger 25. Thereby, the condensation capacity of the outdoor heat exchanger 25 is increased, the amount of refrigerant circulating through the refrigerant circuit of the entire refrigeration apparatus 1 is increased, and the amount of refrigerant accumulated in the receiver 26 is increased. increase.

  On the other hand, when the control unit 230 has already performed control to increase the air volume of the fan mechanism unit 28 with respect to the high-pressure heat source unit (NO in S11), the control unit 230 It is determined whether the high pressure is higher than the high pressures of the other heat source units for a predetermined time t1 (for example, 30 seconds) and the refrigerant is insufficient (S13). Here, the control unit 230 determines that the high pressure of the heat source unit is higher than the high pressures of the other heat source units for a predetermined time t1, and the refrigerant is insufficient. In the case (YES in S13), the rotational speed of the fan motor is further increased by the predetermined value in the drive circuit of the fan mechanism unit 28 of the heat source unit (S12). That is, in the situation where the control unit 230 determines YES in S13 as described above, the outdoor heat exchanger 25 has insufficient ability to draw the refrigerant circulating in the refrigerant circuit 20 into the high-pressure indoor unit. If it is sufficient, the condensation capacity of the outdoor heat exchanger 25 is further improved.

  In S13, the control unit 230 determines that the high pressure of the heat source unit set to the high pressure is higher than a predetermined high pressure lower than the high pressure of the other heat source units. It may be determined whether the time t1 continues and the refrigerant is insufficient. That is, once the drive control of the heat source unit at the time of the refrigerant shortage is entered, the control unit 230 increases the air volume by the fan mechanism unit 28 so that the high pressure of the heat source unit that is set to the high pressure The drive control of the heat source unit at the time of the refrigerant shortage is continued until the pressure further decreases to a value lower than the high pressure of the heat source unit.

  In addition, the control unit 230 does not continue the state where the high pressure of the heat source unit at the high pressure is higher than the high pressure of the other heat source unit for the predetermined time t1, or the refrigerant is insufficient. If it is determined that there is not (NO in S13), has the process for increasing the rotational speed of the fan motor of the fan mechanism section 28 already performed at this time continued for a predetermined time t2 (for example, 5 minutes)? Is determined (S14).

  When the control unit 230 determines that the control for increasing the rotational speed of the fan motor of the fan mechanism unit 28 is within the predetermined time t2 (YES in S14), the control unit 230 performs the increase control of the fan motor rotational speed. Continue (S12). The process by the control part 230 here is a process which maintains a fan motor rotation speed. When it is determined that the control for increasing the rotation speed of the fan motor of the fan mechanism section 28 has exceeded a predetermined time t2 (NO in S14), the control section 230 stops the increase control of the fan motor rotation speed. (S15). That is, the fan mechanism unit 28 is controlled during normal operation.

  Even when the heat source unit drive control at the time of the shortage of refrigerant is performed, if the high pressure of the heat source unit at the high pressure continues to be higher than the high pressure of other heat source units, further drive control is performed for the heat source unit. Is done. FIG. 6 is a flowchart showing further drive control for the heat source unit.

  After performing the drive control of the heat source unit at the time of the refrigerant shortage shown in FIG. 5 for a certain time or a certain number of times, the control unit 230 of the master unit performs the above-described high pressure heat source by the same processing as S2 and S3 described above. It is determined whether the high pressure of the unit is higher than the high pressures of the other heat source units and whether the refrigerant is insufficient. When the high pressure of the heat source unit set to the high pressure continues to be higher than the high pressure of the other heat source units and the controller 230 determines that the refrigerant is insufficient (YES in S21), as shown below, Control is further performed to reduce the load of the compression mechanism 21 of the heat source unit in which the high pressure state continues. On the other hand, when the control unit 230 determines that the high pressure of the heat source unit having the high pressure is higher than the high pressures of the other heat source units and that the two conditions of refrigerant shortage are not satisfied (NO in S21), The process is terminated without performing the subsequent processes.

  In S21, the control unit 230 uses a value indicating that the degree of refrigerant shortage is larger than the value used in the control shown in FIG. When the opening degree of the electric expansion valve 272 is used, it is preferable to determine whether or not the heat source unit in which the high pressure state continues is insufficient by using, for example, 250 pls which is a larger value than the above. .

  In the drive control of the heat source unit, is the control unit 230 of the heat source unit 2a, which is the master unit, first performing control to reduce the load of the compression mechanism 21 on the heat source unit that continues in the high pressure state? It is determined whether or not (S22).

  When the load control of the compression mechanism 21 is not performed for the heat source unit in which the high pressure state continues (YES in S22), the control unit 230 controls the inverter control circuit of the compression mechanism 21 of the heat source unit in which the high pressure state continues. In 225, the compression capacity of the compressor 22 is gradually reduced at a predetermined reduction rate (for example, about 5%) (S23). The load-down process can be performed for only or all of the compressors 22, 23, and 24 constituting the compression mechanism 21, and the compression capacity may be reduced by a necessary amount. In this case, the compressors 23 and 24 are only driven or stopped.

  Furthermore, the control unit 230 performs control to increase the load of each compression mechanism 21 for other heat source units other than the heat source unit that continues to be in the high pressure state (S24). The compression capacity of the compressor 22 is gradually increased at a predetermined increase rate (for example, about 5%) in the drive circuit 225 of the compression mechanism 21 of the other heat source unit. The load-up process can be performed for only one or all of the compressors 22, 23, and 24 constituting the compression mechanism 21, and the compression capacity may be increased by a necessary amount. In this case, the compressors 23 and 24 are only driven or stopped.

  By this S23 and S24, while reducing the flow rate of the refrigerant in the heat source unit in which the high pressure state continues, while increasing the flow rate of the refrigerant in other heat source units other than the heat source unit in which the high pressure state continues, the refrigeration apparatus 1 The refrigerant circulating in the entire refrigerant circuit 20 increases the amount drawn into the heat source unit in which the high pressure state continues, and increases the amount of refrigerant accumulated in the receiver 26. However, the process of S24 can be omitted, and S28 described later is also the same (the omission of S24 and S28 is the same when executing S23 and S27 below).

  On the other hand, if the control unit 230 has already performed load-down control of the compression mechanism 21 with respect to the heat source unit in which the high pressure state continues (NO in S22), the high pressure of the heat source unit in which the high pressure state continues is It is determined whether a state higher than the high pressure of the other heat source unit continues for a predetermined time t3 (for example, 30 seconds) (S25). Here, when the control unit 230 determines that the state in which the high pressure of the heat source unit in which the high pressure state continues is higher than the high pressure of the other heat source unit continues for a predetermined time t3 (YES in S25) ), The load of the compression mechanism 21 of the heat source unit that continues in the high pressure state is further lowered by a predetermined value (S23), and the load-up control (S24) of the compression mechanism 21 of the other heat source unit is performed.

  In S25, the control unit 230 determines that the high pressure of the heat source unit in which the high pressure state continues is higher than a predetermined high pressure lower than the high pressure of other heat source units. It may be determined whether the time t3 continues. That is, once the drive control of the heat source unit at the time of the refrigerant shortage (FIG. 6) is entered, the control unit 230 lowers the load of the compression mechanism 21, and the high pressure of the heat source unit that continues the high pressure state is reduced. The drive control (FIG. 6) of the heat source unit at the time of the refrigerant shortage is continued until the pressure is further lowered to a value lower than the high pressure of other heat source units.

  When the controller 230 determines that the high pressure of the heat source unit that continues to be in the high pressure state is not higher than the high pressure of the other heat source units for the predetermined time t3 (NO in S25). ), It is determined whether the load down control of the compression mechanism 21 is continued for a predetermined time t4 (for example, 2 minutes) (S26).

  When it is determined that the load down control of the compression mechanism 21 is executed within a predetermined time t4 (YES in S26), the control unit 230 performs the load down control of the compression mechanism 21 (S23), The load-up control (S24) of the compression mechanism 21 of the heat source unit is continued. The processing by the control unit 230 here is processing for maintaining the compression capacity of the compression mechanism 21 at this time.

  When the control unit 230 determines that the load down control of the compression mechanism 21 has exceeded the predetermined time t4 (NO in S26), the control unit 230 stops the load down control of the compression mechanism 21 of the heat source unit in which the high pressure state continues. Then (S27), the load-up control of the compression mechanism 21 of the other heat source unit is also stopped (S28). That is, the compression mechanism control during normal operation is performed.

  After the drive control of the heat source unit at the time of the refrigerant shortage shown in FIG. 6 is performed for a certain time or a certain number of times, the control returns to the control shown in FIG.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, after the drive control of the heat source unit at the time of the refrigerant shortage shown in FIG. 5, the control unit 230 determines that the high pressure of the heat source unit set to the high pressure is higher than the high pressure of the other heat source units. If it is determined that the state continues and the refrigerant is insufficient, the control (FIG. 6) for further reducing the load of the compression mechanism 21 of the heat source unit that continues the high pressure state is further performed. Only the drive control of the heat source unit at the time may be performed. In this case, after the drive control of the heat source unit at the time of the refrigerant shortage shown in FIG.

  In addition, the configuration and processing shown in the above embodiment are merely one embodiment of the present invention, and are not intended to limit the present invention to the embodiment described above.

DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 2 Condensing unit set 2a, 2b, 2c Heat-source unit 3a, 3b Indoor unit 4 Liquid side piping 5 Gas side piping 20 Refrigerant circuit 20a Branch circuit 20b Circuit 20c Refrigerant piping 21 Compression mechanism 22, 23, 24 Compressor 25 Outdoor heat exchanger 26 Receiver 27 Intermediate injection circuit 271 Economizer heat exchanger 272 Electric expansion valve 28 Fan mechanism 281 Fan mechanism 200 Outdoor controller 201 High pressure sensor 202 High pressure sensor 203 Refrigerant temperature sensor 204 Refrigerant pressure sensor 210 Determination unit 220 State determination unit 230 Control unit 240 On-off valve control unit

Claims (6)

A condensing unit set (2) that includes a plurality of heat source units (2a to 2c), joins the refrigerants supplied from the plurality of heat source units (2a to 2c), and is used for a refrigeration cycle,
Each of the plurality of heat source units (2a to 2c)
A heat exchanger (25);
A compressor (21) for discharging a high-pressure refrigerant toward the heat exchanger (25);
A fan mechanism (28) for supplying air used for heat exchange to the heat exchanger (25) by rotation of the fan;
A high pressure detector (201) for detecting the high pressure of the high pressure refrigerant discharged from the compressor (21),
As a control unit (200) that performs drive control of the plurality of heat source units (2a to 2c),
Each of the heat source units (2a to 2c) receives each of the high pressures output from the high pressure detector (201), and determines whether the high pressure is higher than the high pressures of the other heat source units A determination unit (210) to perform,
A state discriminating unit (220) for discriminating among the plurality of heat source units (2a to 2c) a heat source unit (2a to 2c) that is in a refrigerant shortage state;
Regarding the heat source unit that has been determined by the determination unit (210) that the high pressure is higher than the high pressure of another heat source unit and that has been determined to be in a refrigerant shortage state by the state determination unit (220), A condensing unit set comprising a controller (230) that drives and controls the fan mechanism (28) of the heat source units (2a to 2c) to increase the rotational speed of the fan. In each of the plurality of heat source units (2a to 2c), a part of the refrigerant that has passed through the economizer heat exchanger (271) is partly injected between the low pressure side and the high pressure side of the compressor (21). An intermediate injection circuit (27) for returning to a refrigerant temperature, and a refrigerant temperature detector (203) for detecting the temperature of the refrigerant after passing through the heat exchanger (25) and the economizer heat exchanger (271),
The state determination unit (220) is a temperature between the refrigerant temperature output from the refrigerant temperature detection unit (203) and a saturation temperature determined by the high pressure output from the high pressure detection unit (201). When the subcool represented by the difference has reached a predetermined value, or in the heat source unit including the refrigerant temperature detection unit (203) and the high pressure detection unit (201), the subcool and other heat source units ( When the difference from the subcool in 2a to 2c) reaches a predetermined value, the heat source unit including the refrigerant temperature detection unit (203) and the high pressure detection unit (201) is in a refrigerant shortage state. The condensing unit set according to claim 1 for discrimination. In each of the plurality of heat source units (2a to 2c), a part of the refrigerant that has passed through the economizer heat exchanger (271) is partly injected between the low pressure side and the high pressure side of the compressor (21). An intermediate injection circuit (27) for returning to the on-off state, an on-off valve (272) for adjusting the refrigerant amount from the intermediate injection circuit (27) to the compressor (21), and an on-off valve control for controlling the opening degree of the on-off valve Part (240),
When the opening degree of the on-off valve (272) output from the on-off valve control unit (240) reaches a predetermined value, the state determination unit (220) 3. The condensing unit set according to claim 1, wherein the heat source unit is determined to be in a refrigerant shortage state. Each of the plurality of heat source units (2a to 2c) includes a high-pressure temperature detector (202) that detects the temperature of the high-pressure refrigerant discharged from the compressor (21).
The state determination unit (220) includes a high-pressure temperature detection unit (202) when the discharge pipe temperature output from the high-pressure temperature detection unit (202) reaches a predetermined temperature. The condensing unit set according to any one of claims 1 to 3, wherein the unit is determined to be in a refrigerant shortage state.   The control unit (230) determines that the high pressure is higher than the high pressure of other heat source units by the determination unit (210), and the state determination unit (220) is in a refrigerant shortage state. The condensing unit set according to any one of claims 1 to 4, wherein, for the determined heat source unit, the compressor (21) of the heat source unit is further driven to reduce its compression capacity.   The control unit (230) determines that the high pressure is higher than the high pressure of other heat source units by the determination unit (210), and the state determination unit (220) is in a refrigerant shortage state. When there is a determined heat source unit, the compressor (21) of the heat source unit that is determined not to be in a refrigerant shortage state by the state determination unit (220) is further driven to increase its compression capacity. The condensing unit set according to any one of claims 1 to 5.

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