Refrigeration cycle device and refrigeration cycle operation control method

Abstract

The present invention comprises: a refrigerant circuit configured by connecting, via pipes, a plurality of heat sources having compressors and condensers and one or a plurality of loads having load throttle devices and evaporators; and a control device configured so that if a shortage of refrigerant used for operation occurs when, among the plurality of heat sources, there is a heat source which has stopped, the control device causes the heat source which has stopped to operate.

Description

Refrigeration cycle device and refrigeration cycle operation control method

[0001] This technology relates to a refrigeration cycle device and a refrigeration cycle operation control method, and particularly to operation control of a refrigeration cycle device having a plurality of heat source units in a refrigerant circuit of the same system.

[0002] Refrigeration cycle devices generally cool or heat a thermal load (hereinafter referred to as "load") using a refrigerant circuit having component devices such as a load heat exchanger, a compressor, a heat source heat exchanger, a throttling device, etc. Here, there is a multi-type air conditioner, which is a refrigeration cycle device that performs air conditioning by connecting multiple indoor units, which serve as load units that heat or cool the load, and multiple outdoor units, which serve as heat source units that supply capacity to the indoor units, with refrigerant piping to form a refrigerant circuit (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2007-218558

[0004] In a refrigeration cycle system in which multiple heat source units are connected in parallel to form a refrigerant circuit of the same system, when it is not necessary to operate all of the heat source units to supply capacity, operation control may be performed using one-lung operation, in which some of the heat source units are stopped. In this case, the heat source units that are stopped from operating close their valves to prevent refrigerant from flowing in.

[0005] However, when the heat exchanger on the heat source side of a heat source unit functions as a condenser, the valve may fail to close due to malfunction or the presence of foreign matter. In such cases, gaseous refrigerant (hereinafter referred to as gas refrigerant) flows into the heat exchanger of the stopped heat source unit, dissipating heat and causing stagnation, resulting in the accumulation of liquid refrigerant (hereinafter referred to as liquid refrigerant). If refrigerant accumulates in the heat exchanger and uneven distribution of refrigerant occurs in the refrigerant circuit, a shortage of refrigerant circulating through the refrigerant circuit for operation occurs. If there is a shortage of refrigerant for operation, the load unit cannot cool the load, resulting in problems such as insufficient cooling.

[0006] Therefore, an object of the present invention is to provide a refrigeration cycle device and a refrigeration cycle operation control method that perform operation control to eliminate refrigerant shortage.

[0007] The disclosed refrigeration cycle device comprises a refrigerant circuit formed by piping a plurality of heat source units each having a compressor and a condenser to one or more load units each having a load throttling device and an evaporator, and a control device that operates a stopped heat source unit when there is a shortage of refrigerant used for operation when one of the plurality of heat source units is stopped.

[0008] In addition, the disclosed refrigeration cycle operation control method is a refrigeration cycle operation control method that controls the operation of a refrigeration cycle device that forms a refrigerant circuit by connecting multiple heat source machines, each having a compressor and a condenser, to one or multiple load machines through piping to circulate refrigerant, and includes a step of determining whether there is a shortage of refrigerant to be used for operation when any of the multiple heat source machines is stopped, and a step of operating the stopped heat source machine if it is determined that there is a shortage of refrigerant.

[0009] In the disclosed refrigeration cycle device, when multiple heat source units are connected to a refrigerant circuit and a refrigerant shortage occurs while one of the heat source units is stopped, the control device operates the stopped heat source unit. By operating the stopped heat source unit, the refrigerant stored in the stopped heat source unit can be used for operation, correcting the uneven distribution of refrigerant and eliminating the refrigerant shortage. This prevents the load unit from being undercooled.

[0010] Fig. 1 is a diagram showing the configuration of an air conditioning apparatus 1 according to embodiment 1. Fig. 2 is a diagram showing the configuration of a load machine 200 according to embodiment 1. Fig. 3 is a diagram showing the configuration of a heat source machine 100 according to embodiment 1. Fig. 4 is a diagram explaining the flow of processing related to eliminating a refrigerant shortage according to embodiment 1.

[0011] Refrigeration cycle devices and the like according to embodiments will be described below with reference to the drawings. In each drawing, components with the same reference numerals are identical or equivalent, and this applies throughout the following embodiments. The dimensional relationships between components in the drawings may differ from those in reality. The configurations of components shown throughout the specification are merely illustrative and are not limited to those described in the specification. In particular, the combinations of components are not limited to those in each embodiment, and components described in other embodiments may be applied to other embodiments. Furthermore, the levels of pressure, temperature, and the like are not determined in relation to absolute values, but are determined relatively in terms of the state, operation, and so forth of the device. When multiple similar devices are distinguished by subscripts, the subscripts may be omitted if there is no need to distinguish or identify them.

[0012] Embodiment 1. FIG. 1 is a diagram showing the configuration of an air conditioner 1 according to embodiment 1. As shown in FIG. 1, the air conditioner 1 is a device that adjusts the air in an indoor space, which is a thermal load, to perform heating and cooling. Here, the air conditioner 1 will be described as an example of a refrigeration cycle device. As shown in FIG. 1, the air conditioner 1 connects multiple heat source units 100 and multiple load units 200 to form the same system using liquid refrigerant piping 300 and gas refrigerant piping 400. The equipment inside the heat source units 100 and the equipment inside the load units 200 are connected via piping to form a refrigerant circuit through which the refrigerant circulates. Here, two heat source units 100 (heat source unit 100A and heat source unit 100B) and two load units 200 (load unit 200A and load unit 200B) are connected. Combining multiple heat source units 100 functions as a combined heat source unit. However, this is not limited thereto, and the air conditioner 1 may also have three or more heat source units 100 and load units 200.

[0013] FIG. 2 is a diagram illustrating the configuration of a load machine 200 according to the first embodiment. Here, it is assumed that the load machine 200A and the load machine 200B shown in FIG. 1 have the same configuration. The load machine 200 is an indoor unit installed indoors and supplies conditioned air. The load machine 200 according to the first embodiment includes a load heat exchanger 210 and a load throttling device 220 as components of a refrigerant circuit. The load machine 200 also includes a load fan 230. The load heat exchanger 210 exchanges heat between the refrigerant and the air to be conditioned. For example, the load heat exchanger 210 functions as a condenser during heating operation, condensing and liquefying the refrigerant. The load heat exchanger 210 also functions as an evaporator during cooling operation, evaporating and vaporizing the refrigerant. The load throttling device 220 is a device that includes a pressure reducing valve or an expansion valve that reduces the pressure and expands the refrigerant. Here, the subcooling throttling device 170 includes an electronic expansion valve that opens and closes the valve at a degree of opening based on instructions from the control device 500, which will be described later. The load fan 230 sends the air to be conditioned to the load heat exchanger 210, promoting heat exchange between the air and the refrigerant.

[0014] FIG. 3 is a diagram illustrating the configuration of a heat source unit 100 according to the first embodiment. Here, it is assumed that the heat source units 100A and 100B shown in FIG. 1 have the same configuration. The heat source unit 100 is installed, for example, outside a room to be air-conditioned and serves as an outdoor unit that supplies the capacity (horsepower) required to air-condition the indoor space to a load unit 200. The heat source unit 100 includes, for example, a compressor 110, a flow switching device 120, a heat-source heat exchanger 130, a heat-source throttling device 140, an accumulator 150, a bypass piping 160, a supercooling throttling device 170, and a supercooling heat exchanger 180. The heat source unit 100 is also equipped with a heat-source fan 190 that blows air to the heat-source heat exchanger 130.

[0015] The compressor 110 draws in refrigerant, compresses it, and discharges it at a high temperature and high pressure. The compressor 110 in the first embodiment is configured, for example, as an inverter compressor whose capacity can be controlled. The compressor 110 is driven at a drive frequency F based on instructions from a control device 500 (described later). The flow path switching device 120 is a device that switches between a refrigerant flow path for cooling operation and a refrigerant flow path for heating operation. The flow path switching device 120 has, for example, a four-way valve.

[0016] The heat source heat exchanger 130 exchanges heat between the outdoor air and the refrigerant. The heat source heat exchanger 130 is, for example, a fin-and-tube heat exchanger configured with multiple heat transfer tubes and multiple fins. The heat source heat exchanger 130 functions as a condenser during cooling operation and as an evaporator during heating operation. The heat source fan 190 supplies outdoor air to the heat source heat exchanger 130. Here, the outdoor air is the heat source fluid that is the target of heat exchange with the refrigerant in the heat source heat exchanger 130. However, the heat source fluid is not limited to this, and water or the like may also be used.

[0017] The heat-source throttling device 140 is a device having a pressure reducing valve or an expansion valve that reduces the pressure and expands the refrigerant. Here, the heat-source throttling device 140 has an electronic expansion valve that opens and closes the valve at an opening degree based on instructions from a control device 500, which will be described later. Normally, the heat-source throttling device 140 has the valve fully open during cooling operation. In particular, in the first embodiment, the heat-source throttling device 140 closes the valve when the heat source machine 100 is stopped to prevent the inflow of refrigerant.

[0018] The accumulator 150 is provided in the suction section, which is the suction side of the compressor 110. The accumulator 150 stores excess refrigerant in the refrigerant circulation circuit. For example, the amount of refrigerant required for air conditioning differs between heating operation and cooling operation. Therefore, the accumulator 150 stores excess refrigerant that occurs due to differences in operation. The accumulator 150 also stores excess refrigerant that occurs transiently when the operation changes. Here, in the air conditioning apparatus 1 of embodiment 1, the accumulator 150 stores excess refrigerant, but this is not limited to this. For example, a receiver that stores high-pressure liquid refrigerant may be installed.

[0019] The bypass piping 160 is a piping that allows a portion of the high-temperature, high-pressure refrigerant to bypass and flow into the suction port of the compressor 110. A supercooling throttling device 170 is disposed in the bypass piping 160. The supercooling throttling device 170 is a device having a pressure reducing valve or an expansion valve that reduces the pressure and expands the refrigerant based on instructions from a control device 500, which will be described later. Here, the supercooling throttling device 170 has an electronic expansion valve that opens and closes the valve at an opening degree based on instructions from the control device 500, which will be described later. The subcooling heat exchanger 180 exchanges heat between the medium-temperature, high-pressure refrigerant flowing between the heat source heat exchanger 130 and the heat source throttling device 140 and the low-temperature, low-pressure refrigerant flowing through the bypass piping 160 that has flowed out of the supercooling throttling device 170.

[0020] The control device 500, which serves as a refrigeration cycle operation control device, controls the equipment of the air conditioning device 1 based on the operation details performed by the air conditioning device 1. The control device 500 includes a control processing device 501, a storage device 502, and a timing device 503. The control processing device 501 performs processes such as calculations and judgments based on physical quantity data such as temperature sent from various sensors installed in the air conditioning device 1, and controls the equipment of the air conditioning device 1, such as the compressor 110. Therefore, in the first embodiment, the processes described as being performed by the control device 500 are actually performed by the control processing device 501. In the first embodiment, the control processing device 501 performs processes, particularly those related to correcting a shortage of refrigerant used for operation. The storage device 502 stores data required for the control processing device 501 to perform its processing. The timing device 503 is a device including a timer that measures time when the control processing device 501 makes judgments, etc. The timing device 503 in the first embodiment particularly measures the time related to the non-cooling detection timer, which indicates the time during which the load is not cooled due to a shortage of refrigerant. The location where the control device 500 is installed is not particularly limited.

[0021] Here, the control processing device 501 of the control device 500 is typically configured as a device that performs control and arithmetic processing, such as a microcomputer centered around a CPU (Central Processing Unit). The control processing device 501 pre-programs the processing procedures performed by each unit and executes the program to realize the processing of each unit. Here, for example, the storage device 502 stores program data. However, the realization of processing is not limited to program execution alone, and each unit may be realized by a separate dedicated device. The storage device 502 also includes a volatile storage device (not shown) such as a random access memory (RAM) that can temporarily store data, and a hard disk, a non-volatile auxiliary storage device (not shown) such as a flash memory that can store data for a long period of time.

[0022] The air conditioning apparatus 1 includes various sensors as detection devices that detect physical quantities required for control by the control device 500. The compressor discharge temperature sensor 510 installed in the heat source unit 100 detects the temperature of the refrigerant discharged from the compressor 110. The high-pressure pressure sensor 520 detects the pressure of the refrigerant discharged from the compressor 110. For example, the discharge superheat degree TdSH can be obtained based on the temperature detected by the compressor discharge temperature sensor 510 and the pressure detected by the high-pressure pressure sensor 520. The two heat-source heat exchanger temperature sensors 530 each detect the temperature of the refrigerant flowing into and out of the heat-source heat exchanger 130. For example, the subcooling degree SCO during cooling operation can be obtained based on the refrigerant outlet temperature of the refrigerant flowing out of the heat-source heat exchanger 130 detected by the heat-source heat exchanger temperature sensor 530. The two load heat exchanger temperature sensors 540 installed in the load unit 200 each detect the temperature of the refrigerant flowing into and out of the load heat exchanger 210.

[0023] Next, the operation of each device of the air conditioner 1 will be described based on the flow of refrigerant. First, cooling operation will be described. During cooling operation, the control device 500 adjusts the supercooling throttling device 170 to allow a portion of the refrigerant passing through the main refrigerant circuit to pass through the bypass piping 160. The high-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 110 passes through the flow switching device 120 and flows into the heat-source heat exchanger 130. The refrigerant then passes through the heat-source heat exchanger 130 and condenses and liquefies by exchanging heat with outdoor air supplied by the heat-source fan 190. A portion of the refrigerant that passes through the main refrigerant circuit side of the supercooling heat exchanger 180 passes through the bypass piping 160 and is decompressed in the supercooling throttling device 170, becoming a low-temperature, low-pressure refrigerant that passes through the bypass piping side of the supercooling heat exchanger 180. As a result, heat exchange occurs between the refrigerants, and the refrigerant that passes through the main refrigerant circuit side of the supercooling heat exchanger 180 is subcooled. The liquefied refrigerant passes through the load expansion device 220. Here, the refrigerant is decompressed as it passes through the load expansion device 220, and becomes a two-phase gas-liquid state. The refrigerant that has been decompressed and become a two-phase gas-liquid state in the load expansion device 220 passes through the load heat exchanger 210. Then, in the load heat exchanger 210, the refrigerant evaporates, for example, by exchanging heat with the air in the space to be air-conditioned, and the gasified refrigerant passes through the flow switching device 120 and is again drawn into the compressor 110. In this manner, the refrigerant in the air conditioner 1 circulates, and air conditioning related to cooling is performed.

[0024] Next, the operation of each device in the refrigerant circuit during heating operation will be described based on the flow of refrigerant. During heating operation, the control device 500 closes the supercooling throttling device 170. The high-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 110 passes through the flow switching device 120 and flows into the load heat exchanger 210. While passing through the load heat exchanger 210, the gas refrigerant condenses and liquefies by, for example, exchanging heat with the air in the space to be air-conditioned. The condensed and liquefied refrigerant passes through the load throttling device 220. The refrigerant is decompressed as it passes through the load throttling device 220. The refrigerant, decompressed and in a gas-liquid two-phase state by the load throttling device 220, passes through the supercooling heat exchanger 180 and the heat source heat exchanger 130. Here, because the supercooling throttling device 170 is closed, heat exchange between refrigerants does not occur in the supercooling heat exchanger 180. In the heat source heat exchanger 130, the refrigerant evaporates by exchanging heat with the outdoor air sent from the heat source fan 190, and the gasified refrigerant passes through the flow path switching device 120 and the accumulator 150, and is again drawn into the compressor 110. In this way, the refrigerant in the air conditioner 1 circulates, and air conditioning related to heating is performed.

[0025] Fig. 4 is a diagram illustrating the flow of processing related to refrigerant shortage elimination according to the first embodiment. The steps of the refrigerant shortage elimination processing described in Fig. 4 are assumed to be performed by the control device 500 (particularly the control processing device 501). The control device 500 determines whether the air conditioning device 1 is performing cooling operation (step S1). If the control device 500 determines that cooling operation is not being performed, the processing ends.

[0026] When the control device 500 determines that the cooling operation is being performed, it determines whether or not there is a stopped heat source unit 100 (step S2). When the control device 500 determines that there is no stopped heat source unit 100, it returns to step S1 and continues the process.

[0027] When the control device 500 determines that there is a stopped heat source unit 100, it determines whether there is a refrigerant shortage (step S3). When the control device 500 determines that there is no refrigerant shortage, it determines whether an arbitrarily set non-cold temperature detection timer reset condition is satisfied (step S4). When the control device 500 determines that the non-cold temperature detection timer reset condition is satisfied, it resets the non-cold temperature detection timer to 0 (step S5). Then, the control device 500 returns to step S1 and continues processing. Furthermore, when the control device 500 determines that the non-cold temperature detection timer reset condition is not satisfied, it stops timing of the non-cold temperature detection timer (step S6).

[0028] Here, in embodiment 1, the control device 500 determines a refrigerant shortage based on the degree of subcooling SCO of the refrigerant flowing out from the heat source heat exchanger 130, the driving frequency F of the compressor 110 in the operating heat source unit 100, and the discharge superheat TdSH of the refrigerant discharged by the compressor 110.

[0029] The control device 500 calculates a discharge superheat degree TdSH, which is the difference between the discharge temperature detected by the compressor discharge temperature sensor 510 and a saturation temperature Tc converted from the high-pressure detected by the high-pressure pressure sensor 520. The control device 500 also calculates a subcooling degree SCO, which is the difference between the saturation temperature Tc and the refrigerant outflow temperature detected by the heat-source heat exchanger temperature sensor 530.

[0030] The control device 500 then determines whether there is a refrigerant shortage based on the refrigerant shortage determination conditions. The refrigerant shortage determination conditions are conditions (1) to (3), and when all of (1) to (3) are met, the control device 500 determines that there is a refrigerant shortage. Here, the set values ​​set for each condition are merely examples, and are not limited to these, and any value can be set. (1) The degree of supercooling SCO is smaller than the set supercooling degree SCOt (for example, SCO<SCOt, where the set supercooling degree SCOt=3 [K]). (2) The drive frequency F is smaller than the target drive frequency Ft required to obtain the target capacity for the current load machine (for example, F<Ft). (3) The discharge superheat degree TdSH is larger than the set discharge superheat degree TdSHt (for example, discharge superheat degree TdSH>set discharge superheat degree TdSHt, where TdSHt=0.56×saturation temperature Tc+10.05 [K]).

[0031] The conditions for resetting the non-cooling detection timer in step S4 are, for example, the conditions shown in (4) to (6). The control device 500 determines that the non-cooling detection timer reset conditions are satisfied if any of the conditions shown in (4) to (6) are satisfied. (4) The degree of supercooling SCO is greater than the set degree of supercooling SCOt by 2 [K] or more (for example, SCO > SCOt + 2 [K]). (5) The drive frequency F is greater than 1.2 times the target drive frequency Ft (for example, the drive frequency F is greater than 120% of the target drive frequency Ft. F > 1.2Ft). (6) The discharge superheat TdSH is less than the set discharge superheat TdSHt by 10 [K] or more (for example, TdSH < TdSHt - 10 [K]).

[0032] If the control device 500 determines in step S3 that there is a refrigerant shortage, the timer 503 starts the non-cooling detection timer (step S7). The control device 500 then determines whether the timer has counted for a set time of 300 seconds or more (step S8). If the control device 500 determines that the timer has not counted for 300 seconds or more, the process returns to step S1 and continues. Here, the set time is set to 300 seconds, but this is not limited to this and can be set arbitrarily.

[0033] On the other hand, if the control device 500 determines that the time counted by the non-cooling detection timer is 300 seconds or more, it determines whether the load Ht of the load unit 200 is equal to or greater than the load setting value A (step S9). Here, when multiple load units 200 are operating, the load Ht is the total load. If the control device 500 determines based on the comparison that the load Ht is equal to or greater than the load setting value A, it starts operation of the stopped heat source unit 100 (step S10). Then, the control device 500 controls the opening of the load throttling device 220 of the load unit 200 to an opening equal to or greater than the maximum opening possible in normal operation. During cooling operation to cool the load, the opening of the load throttling device 220 is not normally controlled to be larger than necessary. However, starting operation of the stopped heat source unit 100 increases the total drive frequency F of the multiple compressors 110, increasing the amount of refrigerant circulating through the refrigerant circuit and reducing the pressure at the suction section on the suction side of the compressor 110. Therefore, in order to suppress the pressure drop in the suction section, the control device 500 temporarily widens the opening of the load throttling device 220 to an opening larger than the maximum opening that can be widened in normal operation based on performance. The control device 500 also controls the heat source throttling device 140 to be fully open (step S11). After temporarily widening the opening of the load throttling device 220, the control device 500 controls the opening of the load throttling device 220 while performing normal operation.

[0034] In step S9, when the control device 500 determines based on the comparison that the load Ht of the load device 200 is not equal to or greater than the load set value A, it stops one of the operating heat source devices 100. Then, the control device 500 starts operation of the one stopped heat source device 100 (step S12).

[0035] The control device 500 then determines whether there is one heat source device 100 in operation (step S13). If the control device 500 determines that there is one heat source device 100 in operation, it drives the compressor 110 at the minimum drive frequency possible in normal operation. The control device 500 also drives the heat source fan 190 at the maximum drive frequency possible in normal operation (step S14). After driving the compressor 110 at the minimum drive frequency and the heat source fan 190 at the maximum drive frequency, the control device 500 performs control to adjust the drive frequencies of the compressor 110 and the heat source fan 190 during normal operation.

[0036] Furthermore, in step S13, if the control device 500 determines that more than one heat source device 100 is in operation, it controls the opening degree of the load throttling device 220 of the load device 200 to an opening degree equal to or greater than the maximum opening degree possible in normal operation. Furthermore, the control device 500 controls the heat source throttling device 140 to be fully open (step S11). The control device 500 performs the above refrigerant shortage resolution process at regular intervals.

[0037] As described above, in the air conditioning apparatus 1 having a plurality of heat source units 100 according to the first embodiment, when the control device 500 determines that there is a shortage of refrigerant to be used for operation when there is a stopped heat source unit 100, it operates the stopped heat source unit 100. As a result, the refrigerant that had accumulated in the stopped heat source unit 100 is circulated in the refrigerant circuit and used for operation, correcting the uneven distribution of refrigerant and eliminating the refrigerant shortage related to operation. Therefore, it is possible to prevent the load unit 200 from being insufficiently cooled.

[0038] Furthermore, in the first embodiment, the control device 500 determines a refrigerant shortage based on the degree of subcooling SCO of the refrigerant flowing out from the heat source heat exchanger 130, the drive frequency F of the compressor 110 in the operating heat source device 100, and the discharge superheat TdSH of the refrigerant discharged from the compressor 110. This allows the control device 500 to accurately determine a refrigerant shortage. At this time, if the control device 500 determines that the time measured by the non-cooling detection timer measured by the timing device 503 is equal to or greater than the set detection time, the control device 500 operates the stopped heat source device 100, thereby enabling an even more accurate determination.

[0039] In the first embodiment, when the load Ht of the load unit 200 is less than the load setting value A, the control device 500 starts operation of one of the heat source units 100 that is currently stopped, and stops one of the heat source units 100 that is currently operating. This prevents excessive capacity supply by the combined heat source units, enabling efficient operation.

[0040] In the first embodiment, when a stopped heat source unit 100 is started up, causing a plurality of heat source units 100 to operate, the control device 500 controls the load throttling device 220 to open to a degree greater than the normal maximum opening degree, thereby enabling the refrigerant accumulated in the heat source heat exchanger 130 to be quickly circulated through the refrigerant circuit.

[0041] In the first embodiment, the heat source heat exchanger 130 is a heat exchanger that functions as a condenser or an evaporator depending on the refrigerant flow path, but this is not limited to this. For example, the heat source heat exchanger 130 may be a condenser that only performs condensation.

[0042] In the first embodiment described above, the valve that closes the flow path to prevent the refrigerant from flowing in when the heat source device 100 is stopped is the heat source throttle device 140, the opening degree of which can be changed as desired, but this is not limited to this. For example, in a case where the heat source heat exchanger 130 is a condenser, the valve may be an on-off valve.

[0043] In the first embodiment and the like described above, the air conditioner 1 has been described as an example of a refrigeration cycle device, but the present invention is not limited to this. For example, the present invention can be applied to other refrigeration cycle devices, such as a refrigerator (where the load device 200 is a cooler) or a refrigeration device (where the load device 200 is a refrigerator) in which the heat source heat exchanger 130 of the heat source device 100 serves as a condenser.

[0044] 1 Air conditioning apparatus, 100, 100A. 100B Heat source machine, 110 Compressor, 120 Flow path switching device, 130 Heat source heat exchanger, 140 Heat source throttling device, 150 Accumulator, 160 Bypass piping, 170 Supercooling throttling device, 180 Supercooling heat exchanger, 190 Heat source fan, 200, 200A. 200B Load machine, 210 Load heat exchanger, 220 Load throttling device, 230 Load fan, 300 Liquid refrigerant piping, 400 Gas refrigerant piping, 500 Control device, 501 Control processing device, 502 Storage device, 503 Timing device, 510 Compressor discharge temperature sensor, 520 High pressure pressure sensor, 530 Heat source heat exchanger temperature sensor, 540 Load heat exchanger temperature sensor.

Claims

1. A refrigeration cycle device comprising: a refrigerant circuit configured by piping together a plurality of heat source units each having a compressor and a condenser and one or more load units each having a load throttling device and an evaporator; and a control device which, when one of the plurality of heat source units is stopped and there is a shortage of refrigerant used for operation, operates the stopped heat source unit.

2. A refrigeration cycle device as described in claim 1, wherein the control device determines whether or not a shortage of the refrigerant is occurring based on the drive frequency of the compressor, the discharge superheat of the refrigerant discharged by the compressor, and the subcooling degree of the refrigerant flowing out of the condenser.

3. A refrigeration cycle device as described in claim 1 or claim 2, wherein the control device measures the time since it is determined that the refrigerant is insufficient, and when the time during which the refrigerant is insufficient reaches or exceeds a set time, the control device operates the heat source unit that is stopped.

4. A refrigeration cycle device as described in any one of claims 1 to 3, wherein when the control device determines that the total load cooled by the load units is less than a load set value when operating the heat source units that are stopped, it performs operation control to stop one of the heat source units that are operating and operate one of the heat source units that is stopped.

5. A refrigeration cycle apparatus as described in any one of claims 1 to 4, wherein the control device operates the heat source unit that is stopped, and when operating multiple heat source units, controls the load throttling device of the load unit to an opening degree greater than the normal maximum opening degree.

6. A refrigeration cycle operation control method for controlling the operation of a refrigeration cycle device that configures a refrigerant circuit in which a plurality of heat source units each having a compressor and a condenser are connected to one or a plurality of load units through piping to circulate a refrigerant, the method comprising the steps of: determining whether or not there is a shortage of the refrigerant used for operation of the plurality of heat source units when any of the heat source units is stopped; and operating the stopped heat source unit when it is determined that there is a shortage of the refrigerant.

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