JP2019066053A - Refrigerant cycle device - Google Patents

Abstract

To provide a refrigerant cycle device capable of inhibiting opening control of an expansion valve from being performed while a temperature drop of a refrigerant caused by flash gas is wrongly recognized as a supercooling state.SOLUTION: A refrigerant cycle device 100 includes: a refrigerant circuit 80 having a compressor 12, a condenser 20, an expansion valve 18 and an evaporator 62; a first temperature sensor 92c; a second temperature sensor 92d; and a controller 70. The first temperature sensor measures a temperature of a refrigerant flowing in the condenser on the upstream side of a flow diverter 25 of the condenser in a refrigerant flowing direction as a first temperature. The second temperature sensor measures a refrigerant temperature on the downstream side of the flow diverter and on the upstream side of the electric expansion valve in the refrigerant flowing direction as a second temperature. The controller calculates each of a temperature difference (first temperature difference) between the first temperature and a condensation temperature and a temperature difference (second temperature difference) between the second temperature and the condensation temperature. Based on the first temperature difference and the second temperature difference, the controller performs opening control of the expansion valve.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a refrigerant cycle device, and more particularly to a refrigerant cycle device in which the opening degree of an expansion valve is adjusted according to the degree of subcooling.

  Conventionally, a refrigerant cycle device of a vapor compression type, in which the opening degree of an expansion valve is adjusted in accordance with the degree of subcooling, is known. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-137165), a condensing temperature and an outlet temperature of a condenser are obtained by measurement, and a refrigerant whose opening degree is controlled so that the difference becomes a target value. A cycle device is disclosed.

  According to Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-137165), when the opening degree control of the expansion valve is not appropriate, the temperature of the refrigerant in the subcooled state is erroneously detected as the condensation temperature, and thereby the expansion valve It is stated that there is a problem that the opening degree of the valve is excessively narrowed. And in order to solve this subject, patent document 1 (Unexamined-Japanese-Patent No. 2013-137165) estimates condensation temperature from the electric current value and rotation speed of a motor of a compressor, and the estimated degree of supercooling is a measurement actual degree of supercooling In the case where the temperature is larger, it is described that the opening degree of the expansion valve is once increased to eliminate the state in which the temperature of the refrigerant in the supercooled state is erroneously detected as the condensation temperature.

  On the other hand, in the refrigerant cycle device as disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-137165), the inventor of the present invention has used the pressure loss portion of the condenser (for example, the merging portion of the flow path or the reduction portion of the flow path area In some cases, flash gas is generated depending on the operating conditions, and the outlet temperature of the condenser is lowered accordingly, so it is judged that supercooling is attached even though it is not actually supercooled. , It was found that there is a problem that the opening degree of the expansion valve becomes too large.

  An object of the present disclosure is to provide a highly reliable refrigerant cycle device capable of suppressing the adjustment of the opening degree of the expansion valve in the state where the temperature decrease of the refrigerant due to the generation of the flash gas is misunderstood as the overcooling state. is there.

  The refrigerant cycle device includes a refrigerant circuit, a first temperature measurement unit, a second temperature measurement unit, a calculation unit, and a control unit. The refrigerant circuit includes a compressor, a condenser, an expansion valve, and an evaporator. The compressor compresses the refrigerant. The condenser cools and condenses the refrigerant compressed by the compressor. The expansion valve depressurizes the refrigerant condensed by the condenser. The evaporator heats and evaporates the refrigerant flowing from the condenser through the expansion valve. The first temperature measurement unit measures, as a first temperature, the temperature of the refrigerant flowing through the condenser on the upstream side of the pressure loss portion of the condenser in the flow direction of the refrigerant. The second temperature measurement unit measures, as a second temperature, a refrigerant temperature downstream of the pressure loss unit and upstream of the expansion valve in the flow direction of the refrigerant. The calculation unit calculates the temperature difference between the second temperature and the condensation temperature as the second temperature difference, with the temperature difference between the first temperature and the condensation temperature in the condenser as the first temperature difference. The control unit adjusts the opening degree of the expansion valve based on the first temperature difference and the second temperature difference.

  In this refrigerant cycle device, the opening degree adjustment of the expansion valve based on the first temperature difference is also performed, so even if the flash gas is generated in the pressure loss portion, the temperature drop of the refrigerant due to the generation of the flash gas is supercooled It can be suppressed that the opening degree adjustment of the expansion valve is performed in the state that it is misidentified as.

  Preferably, in the refrigerant cycle device, the control unit selects one of the first temperature difference and the second temperature difference based on the first temperature and the second temperature, and the opening degree of the expansion valve based on the selected temperature difference. Make adjustments.

  Here, it can be suppressed that the opening degree adjustment of the expansion valve is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is mistaken as the overcooling state.

  Preferably, in the refrigerant cycle device, the control unit compares the first temperature difference and the second temperature difference, selects one of the first temperature difference and the second temperature difference based on the comparison result, and selects the selected temperature difference. Adjust the opening degree of the expansion valve based on.

  Here, it can be suppressed that the opening degree adjustment of the expansion valve is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is mistaken as the overcooling state.

  More preferably, in the refrigerant cycle device, the control unit selects the smaller one of the first temperature difference and the second temperature difference, and adjusts the opening degree of the expansion valve based on the selected temperature difference.

  Here, it can be suppressed that the opening degree adjustment of the expansion valve is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is mistaken as the overcooling state.

  Preferably, in the refrigerant cycle device, the control unit is based on the first temperature difference until the predetermined time elapses from the start of operation of the refrigerant cycle device, and the second temperature difference after the predetermined time elapses from the start of operation. Adjust the opening degree of the expansion valve.

  Here, it can be suppressed that the opening degree adjustment of the expansion valve is performed in a state in which the temperature decrease of the refrigerant accompanying the generation of the flash gas in the pressure loss portion is misunderstood as the overcooling state.

  Further preferably, in the refrigerant cycle device, the pressure loss portion is a merging portion of the refrigerant flow path in the refrigerant flow direction.

  Here, even if the flash gas is generated at the merging portion of the refrigerant flow path, it is possible to suppress the adjustment of the opening degree of the expansion valve in the state where the temperature decrease of the refrigerant due to the generation of the flash gas is misunderstood as the supercooling state.

  Preferably, in the refrigerant cycle device, the pressure loss portion is a reduction portion of the refrigerant flow area.

  Here, even if the flash gas is generated in the portion where the refrigerant flow path is reduced, it can be suppressed that the expansion valve adjustment of the expansion valve is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas .

  Still preferably, in a refrigerant cycle device, the condenser includes a main heat exchange portion, a sub heat exchange portion, and a connection portion which brings together the refrigerant flowing through the main heat exchange portion and leads the refrigerant to the sub heat exchange portion. The pressure loss part is a connection part.

  Here, even if the flash gas is generated at the connection portion between the main heat exchange portion and the sub heat exchange portion, the opening degree adjustment of the expansion valve is performed in a state that the temperature decrease of the refrigerant due to the generation of the flash gas It can control what is done.

  Preferably, in the refrigerant cycle device, the first temperature measurement unit measures the temperature of the refrigerant flowing downstream of the center of the inlet of the condenser and the outlet of the condenser in the refrigerant flow path of the condenser.

  Here, it is possible to measure the temperature of the subcooled liquid refrigerant as the first temperature.

  Preferably, in the refrigerant cycle device, the condenser has a heat exchange unit disposed upstream of the junction in the refrigerant flow direction, and a plurality of pipes connecting the heat exchange unit and the junction. . Preferably, the first temperature measurement unit measures the temperature of the refrigerant flowing downstream from the center of the heat exchange unit in the flow direction of the refrigerant.

  Here, it is possible to measure the temperature of the subcooled liquid refrigerant as the first temperature.

  More preferably, in the refrigerant cycle device, the first temperature measurement unit measures the temperature of the refrigerant flowing through one of a plurality of pipes connecting the heat exchange unit and the junction.

  Here, it is easy to measure the temperature of the subcooled liquid refrigerant as the first temperature.

  More preferably, in the refrigerant cycle device, the first temperature measurement unit measures the temperature of the refrigerant flowing downstream of the center of the heat exchange unit and the joining unit of the pipe in the flow direction of the refrigerant.

  Here, it is easy to measure the temperature of the subcooled liquid refrigerant as the first temperature.

  Further preferably, in the refrigerant cycle device, the plurality of pipes connecting the heat exchange unit and the joining unit are connected to the heat exchange unit at different heights. Preferably, the first temperature measurement unit measures the temperature of the refrigerant flowing through a pipe connected to the heat exchange unit at the lowest position.

  Here, it is easy to measure the temperature of the subcooled liquid refrigerant as the first temperature.

It is a schematic block diagram of the refrigerant cycle device concerning one embodiment of this indication. It is a control block diagram of the refrigerant cycle device of FIG. When flash gas generate | occur | produces with a flow divider, it is a typical pressure-enthalpy diagram for demonstrating the reason for being difficult to calculate a degree of subcooling accurately using a 2nd temperature sensor. It is an example of the flowchart of opening degree control of the expansion valve at the time of cooling operation in the refrigerant cycle device of FIG. It is an example of the flowchart regarding the selection process of the temperature difference utilized for opening control of the expansion valve in the flowchart of FIG. It is another example of the flowchart of opening degree control of the expansion valve at the time of cooling operation in the refrigerant cycle device of modification B. FIG. 16 is a schematic configuration diagram of a refrigerant cycle device of Modification D.

  Embodiments of the refrigerant cycle device of the present disclosure will be described with reference to the drawings.

(1) Overall Configuration FIG. 1 is a schematic configuration diagram of a refrigerant cycle device 100 according to an embodiment.

  Here, the refrigerant cycle device 100 is an air conditioner that cools / heats the interior of a building with a vapor compression refrigeration cycle. However, the refrigerant cycle device 100 may be a device used for applications other than air conditioning and heating, such as a water heater and a dehumidifier.

  The refrigerant cycle device 100 mainly includes a heat source unit 10, a utilization unit 60, a liquid refrigerant communication pipe 46, and a gas refrigerant communication pipe 48. The liquid refrigerant communication pipe 46 and the gas refrigerant communication pipe 48 are pipes that connect the heat source unit 10 and the usage unit 60. The liquid refrigerant communication pipe 46 and the gas refrigerant communication pipe 48 are pipes that are installed on site when the refrigerant cycle device 100 is installed.

  In addition, although the number of the utilization units 60 is one in this embodiment, the refrigerant cycle device 100 may have a plurality of utilization units 60 connected in parallel to each other.

  The heat source unit 10 and the utilization unit 60 are connected via the liquid refrigerant communication pipe 46 and the gas refrigerant communication pipe 48, whereby a refrigerant circuit 80 is configured. The refrigerant circuit 80 mainly includes the compressor 12 of the heat source unit 10, the heat source side heat exchanger 20 and the expansion valve 18, and the use side heat exchanger 62 of the use unit 60.

  The refrigerant used in the refrigerant cycle device 100 is not limited, but is, for example, a fluorocarbon refrigerant such as R32.

(2) Detailed Configuration (2-1) Usage Unit The usage unit 60 is installed in an air conditioning target space such as a building interior.

  For example, the usage unit 60 is a ceiling-embedded unit installed on a ceiling. However, the usage unit 60 is not limited to the ceiling-embedded unit, and may be a ceiling-hanging type, a wall-hanging type installed on a wall, a floor-standing type installed on a floor, etc. Good.

  The utilization unit 60 is connected to the heat source unit 10 via the liquid refrigerant communication pipe 46 and the gas refrigerant communication pipe 48 as described above, and constitutes a part of the refrigerant circuit 80.

  The configuration of the usage unit 60 will be described below.

  The usage unit 60 mainly includes a usage-side heat exchanger 62, a usage-side fan 66, and a usage-side control unit 74 (see FIG. 1). Further, the utilization unit 60 connects the liquid refrigerant pipe 67 connecting the liquid side of the utilization side heat exchanger 62 and the liquid refrigerant communication pipe 46, and connects the gas side of the utilization side heat exchanger 62 and the gas refrigerant communication pipe 48. And a gas refrigerant pipe 68 (see FIG. 1).

  The use-side heat exchanger 62 is not limited to the type, but for example, a cross fin type fin-and-tube heat composed of a heat transfer tube (not shown) and a large number of fins (not shown) It is an exchanger. In the use side heat exchanger 62, heat exchange is performed between the refrigerant flowing through the use side heat exchanger 62 and the indoor air (air in the space to be air-conditioned). The liquid side end of the use side heat exchanger 62 is connected to the liquid refrigerant pipe 67, and the gas side end is connected to the gas refrigerant pipe 68.

  The use side heat exchanger 62 functions as an evaporator that heats and evaporates the refrigerant flowing from the heat source side heat exchanger 20 as a condenser through the expansion valve 18 during the cooling operation described later. In addition, the use-side heat exchanger 62 functions as a condenser that cools and condenses the refrigerant compressed by the compressor 12 during a heating operation described later.

  The use side fan 66 is a fan that sucks indoor air into the use unit 60 and supplies it to the use side heat exchanger 62 and supplies the air heat-exchanged with the refrigerant in the use side heat exchanger 62 into the room. The use side fan 66 is, for example, a centrifugal fan such as a turbo fan or sirocco fan. However, the type of fan is not limited to the centrifugal fan, and may be appropriately selected. The use side fan 66 is driven by a fan motor 65.

  The use side control unit 74 controls the operation of each unit constituting the use unit 60. The use-side control unit 74 includes a microcomputer, a memory, and the like provided to control the use unit 60. The use side control unit 74 is configured to be able to exchange control signals and the like with the heat source unit 10 via the communication line. In addition, the use-side control unit 74 is configured to be able to receive signals relating to the operation / stop of the refrigerant cycle device 100 transmitted from a remote control (not shown) for operating the usage unit 60, signals relating to various settings, etc. ing.

  Further, the usage unit 60 is provided with various sensors. For example, the use unit 60 is provided with a room temperature sensor (not shown) or the like that measures the temperature of the room air drawn into the use unit 60.

(2-2) Heat source unit The heat source unit 10 is installed, for example, outside the building where the refrigerant cycle device 100 is installed.

  The heat source unit 10 is connected to the utilization unit 60 via the liquid refrigerant communication pipe 46 and the gas refrigerant communication pipe 48 as described above, and constitutes a part of the refrigerant circuit 80.

  The configuration of the heat source unit 10 will be described below.

  The heat source unit 10 mainly includes the compressor 12, the switching mechanism 14, the heat source side heat exchanger 20, the expansion valve 18, the accumulator 16, the bridge circuit 32, the economizer heat exchanger 34, and the injection valve 36. , And a heat source side fan 30 (see FIG. 1). Moreover, the heat source unit 10 has various sensors. The heat source unit 10 further includes a heat source side control unit 72 that controls the operation of each part that constitutes the heat source unit 10 (see FIG. 1).

  The heat source unit 10 further includes a suction pipe 10a, a discharge pipe 10b, a first gas refrigerant pipe 10c, a liquid refrigerant pipe 10d, and a second gas refrigerant pipe 10e (see FIG. 1). The suction pipe 10 a connects the switching mechanism 14 and the suction side of the compressor 12. The discharge pipe 10 b connects the discharge side of the compressor 12 and the switching mechanism 14. The first gas refrigerant pipe 10 c connects the switching mechanism 14 and the gas side end of the heat source side heat exchanger 20. The liquid refrigerant pipe 10 d connects the liquid side end of the heat source side heat exchanger 20 and the liquid refrigerant communication pipe 46. A liquid side shut-off valve 42 is provided at the connection between the liquid refrigerant pipe 10 d and the liquid refrigerant communication pipe 46. The second gas refrigerant pipe 10 e connects the switching mechanism 14 and the gas refrigerant communication pipe 48. A gas side shut-off valve 44 is provided at a connection between the second gas refrigerant pipe 10 e and the gas refrigerant communication pipe 48. The liquid side shutoff valve 42 and the gas side shutoff valve 44 are valves that are manually opened and closed.

  Hereinafter, various configurations of the heat source unit 10 will be further described.

(2-2-1) Compressor The compressor 12 is a device that compresses a refrigerant. The compressor 12 pressurizes the low pressure refrigerant to a high pressure.

  The compressor 12 is not limited in type, but is, for example, a rotary type or scroll type volumetric compressor. The compression mechanism (not shown) of the compressor 12 is driven by a compressor motor 12a (see FIG. 1). Here, the compressor motor 12a is a motor whose rotational speed can be controlled by an inverter or the like. The displacement of the compressor 12 is controlled by controlling the number of revolutions of the compressor motor 12a. The compression mechanism of the compressor 12 may be driven by a prime mover (for example, an internal combustion engine) other than a motor.

(2-2-2) Switching Mechanism The switching mechanism 14 is a mechanism that switches the flow direction of the refrigerant in the refrigerant circuit 80. Here, the switching mechanism 14 is a four-way switching valve.

  During the cooling operation, the switching mechanism 14 brings the suction pipe 10a into communication with the second gas refrigerant pipe 10e and brings the discharge pipe 10b into communication with the first gas refrigerant pipe 10c (see the solid line in the switching mechanism 14 in FIG. 1). That is, the switching mechanism 14 communicates the suction side of the compressor 12 to the gas refrigerant communication pipe 48 through the suction pipe 10a and the second gas refrigerant pipe 10e during the cooling operation, and the discharge side of the compressor 12 the discharge pipe 10b. And the gas side end of the heat source side heat exchanger 20 through the first gas refrigerant pipe 10c. When the switching mechanism 14 connects the piping in such a state, the refrigerant circuit 80 enters the cooling operation state. During the cooling operation (when the refrigerant circuit 80 is in the cooling operation state), the heat source side heat exchanger 20 functions as a condenser (cooler of the refrigerant), and the use side heat exchanger 62 is an evaporator. It functions as a heater for the refrigerant.

  Moreover, the switching mechanism 14 communicates the suction pipe 10a with the first gas refrigerant pipe 10c and communicates the discharge pipe 10b with the second gas refrigerant pipe 10e during heating operation (see the broken line in the switching mechanism 14 in FIG. 1). ). That is, the switching mechanism 14 communicates the suction side of the compressor 12 with the gas side end of the heat source side heat exchanger 20 through the suction pipe 10a and the first gas refrigerant pipe 10c during heating operation, and discharges the compressor 12 The side is connected to the gas refrigerant communication pipe 48 through the discharge pipe 10 b and the second gas refrigerant pipe 10 e. When the switching mechanism 14 connects the piping in such a state, the refrigerant circuit 80 is in the heating operation state. During the heating operation (when the refrigerant circuit 80 is in the heating operation state), the heat source side heat exchanger 20 functions as an evaporator, and the use side heat exchanger 62 functions as a condenser.

  The switching mechanism 14 is not limited to the four-way switching valve, and may be configured to realize switching of the flow direction of the refrigerant as described above by combining a plurality of solenoid valves and a refrigerant pipe.

(2-2-3) Heat source side heat exchanger In the heat source side heat exchanger 20, heat exchange is performed between the refrigerant and the outdoor air. The liquid side end of the heat source side heat exchanger 20 is connected to the liquid refrigerant pipe 10d, and the gas side end is connected to the first gas refrigerant pipe 10c.

  The heat source side heat exchanger 20 is, for example, a fin and tube heat exchanger having a heat transfer pipe (not shown) and a large number of fins (not shown). However, the type of the heat source side heat exchanger 20 is not limited to the fin and tube heat exchanger, and may be another type of heat exchanger.

  The heat source side heat exchanger 20 mainly includes a header 21, a heat exchanger 23 where heat exchange between the refrigerant and the outdoor air is performed, a small diameter pipe 24, a flow divider 25, and a main pipe 26 (see FIG. See Figure 1). The heat exchange unit 23 includes a main heat exchange unit 22 and an auxiliary heat exchange unit 28 (see FIG. 1). The main heat exchange unit 22 and the auxiliary heat exchange unit 28 include a heat transfer pipe (not shown) and a large number of fins (not shown).

  The header 21 is formed in a vertically long cylindrical shape. The first gas refrigerant pipe 10 c is connected to the header 21. The first gas refrigerant pipe 10 c communicates with the internal space of the header 21. The first gas refrigerant pipe 10 c is connected to the gas side connection port 20 a of the header 21. Also, the header 21 is connected to the main heat exchange unit 22 by a plurality of header communication pipes 21 a. The internal space of the header 21 and the heat transfer pipe (not shown) of the main heat exchange unit 22 communicate with each other via the header connection pipe 21a.

  In the main heat exchange unit 22, heat exchange is performed between the refrigerant flowing through a plurality of heat transfer pipes (not shown) of the main heat exchange unit 22 and the outdoor air. The plurality of heat transfer tubes of the main heat exchange section 22 preferably extend in the horizontal direction. In the main heat exchange section 22, the plurality of heat transfer pipes of the main heat exchange section 22 are vertically divided into a plurality of systems, and the heat transfer pipes of the plurality of systems form mutually independent coolant channels. And one of the plurality of header communication pipes 21a is connected to one end side of each refrigerant flow path, and one of the plurality of small diameter pipes 24 is connected to the other end side (see FIG. 1). ). Each of the small diameter tubes 24 is connected to the lower part of each refrigerant flow path.

  In FIG. 1, a state in which three header communication pipes 21 a and three small diameter pipes 24 are connected to the main heat exchange unit 22 is drawn. In other words, in FIG. 1, the main heat exchange unit 22 has three refrigerant flow paths (first refrigerant flow path 22a, second refrigerant flow path 22b, and third refrigerant flow path 22c in order from the bottom). It is drawn. However, the aspect of FIG. 1 is only an illustration for description, and the main heat exchange part 22 may be divided into two or four or more systems. Then, the numbers of the header connection pipes 21a and the small diameter pipes 24 may be determined according to the number of systems (the number of refrigerant channels).

  Each of the plurality of small diameter tubes 24 is connected to one of the independent refrigerant flow paths of the main heat exchange unit 22. In the present embodiment, the small diameter pipe 24 includes a first small diameter pipe 24a connected to the first refrigerant flow channel 22a, a second small diameter pipe 24b connected to the second refrigerant flow channel 22b, and a third refrigerant flow And a third small diameter tube 24c connected to the passage 22c. The end of the first small diameter pipe 24a, the second small diameter pipe 24b and the third small diameter pipe 24c opposite to the side connected to the main heat exchange section 22 is connected to the upper end of the flow divider 25 ing.

  A plurality of small diameter pipes 24 are connected to the upper end portion of the flow distributor 25 and a main pipe 26 is connected to the lower end portion thereof (see FIG. 1). The main pipe 26 and the plurality of small diameter pipes 24 communicate with each other inside the flow divider 25. The end of the main pipe 26 opposite to the end connected to the flow divider 25 is connected to the auxiliary heat exchange unit 28.

  The auxiliary heat exchange unit 28 is disposed below the main heat exchange unit 22. The arrangement of the auxiliary heat exchange unit 28 is not limited to the lower side of the main heat exchange unit 22. However, in order to suppress frost formation on the lower part of the heat exchange part where frost formation easily occurs, the secondary heat exchange part 28 through which the refrigerant of relatively high temperature flows during the heating operation is disposed below the main heat exchange part 22 Is preferred.

  In the auxiliary heat exchange unit 28, heat exchange is performed between the refrigerant flowing through a heat transfer pipe (not shown) of the auxiliary heat exchange unit 28 and the outdoor air. The main pipe 26 is connected to one end side of the refrigerant flow passage of the sub heat exchange unit 28, and the liquid refrigerant pipe 10 d is connected to the other end side of the refrigerant flow passage of the sub heat exchange unit 28. The liquid refrigerant pipe 10 d is connected to the liquid side connection port 20 b provided in the sub heat exchange unit 28.

  In the case where the refrigerant flows from the first gas refrigerant pipe 10c toward the liquid refrigerant pipe 10d in the heat source side heat exchanger 20 (during the cooling operation, refer to the flow direction A of the refrigerant in FIG. 1), the refrigerant is the heat source side heat In the exchanger 20, the internal space of the header 21, the header communication pipe 21a, the main heat exchange section 22, the small diameter pipe 24, the flow divider 25, the main pipe 26, and the sub heat exchange section 28 flow in this order. When the refrigerant flows from the first gas refrigerant pipe 10c toward the liquid refrigerant pipe 10d in the heat source side heat exchanger 20, the heat source side heat exchanger 20 is a condenser that cools and condenses the refrigerant compressed by the compressor 12 Act as.

  More specifically, the flow of the refrigerant when the refrigerant flows from the first gas refrigerant pipe 10c to the liquid refrigerant pipe 10d (during the cooling operation) in the heat source side heat exchanger 20 will be described.

  During the cooling operation, the refrigerant (mainly in the gas phase) flowing through the first gas refrigerant pipe 10c flows into the internal space of the header 21 from the gas side connection port 20a (the inlet of the condenser). The refrigerant that has flowed into the header 21 is divided into three header communication pipes 21 a and flows, and the refrigerant flow paths of the main heat exchange unit 22 (the first refrigerant flow path 22 a, the second refrigerant flow path 22 b, and the third refrigerant flow path Flow into 22c). The refrigerants cooled by the first refrigerant channel 22a, the second refrigerant channel 22b, and the third refrigerant channel 22c flow into the first small diameter pipe 24a, the second small diameter pipe 24b, and the third small diameter pipe 24c, respectively. Flows into the flow divider 25.

  The flow divider 25 functions as a merging portion of the refrigerant flow path in the refrigerant flow direction A during the cooling operation. That is, the flow divider 25 is an example of a connection unit that causes the refrigerant flowing through the main heat exchange unit 22 to be joined and led to the sub heat exchange unit 28.

  Further, the flow divider 25 is a reduction portion of the refrigerant flow passage area in the flow direction of the refrigerant during the cooling operation. In addition, the reduction | decrease part of a refrigerant | coolant flow passage area means the part to which a refrigerant | coolant flow passage area reduces to 80% or less compared with the upstream here.

  The flow divider 25 is an example of a pressure loss unit.

  The pressure loss portion is a portion where the pressure drop can be larger when flowing the refrigerant to the heat source side heat exchanger 20 that functions as a condenser, compared to the upstream side. In other words, the pressure loss portion means a portion where the friction loss and the shape loss increase when flowing the refrigerant to the heat source side heat exchanger 20 that functions as a condenser as compared with the upstream side. For example, in addition to the merging portion of the refrigerant flow path, the branched portion of the refrigerant flow path, the curved portion of the refrigerant flow path, the enlarged portion of the refrigerant flow path (including the rapid expansion portion and the diffuser), and the reduced portion of the refrigerant flow path A reduced portion, including a nozzle), etc. can be a pressure loss portion.

  For example, when the pressure loss part flows the refrigerant to the heat source side heat exchanger 20 that functions as a condenser, the average value of the pressure loss (rate of change in pressure drop) per unit flow path length (Inside heat exchanger 20) more than twice the average value of the pressure loss per unit flow path length.

  The refrigerant flowing into the flow distributor 25 passes through the main pipe 26 and flows into the secondary heat exchange unit 28. The refrigerant cooled by the auxiliary heat exchange unit 28 flows into the liquid refrigerant pipe 10 d from the liquid side connection port 20 b (outlet of the condenser) provided in the auxiliary heat exchange unit 28.

  On the other hand, when the refrigerant flows from the liquid refrigerant pipe 10d toward the first gas refrigerant pipe 10c (during the heating operation), the refrigerant flows from the heat source side heat exchanger 20 to the subheat It flows in order of the exchange part 28, the main pipe 26, the flow divider 25, the small diameter pipe 24, the main heat exchange part 22, the header communication pipe 21a, and the internal space of the header 21. When the refrigerant flows from the liquid refrigerant pipe 10d toward the first gas refrigerant pipe 10c, the heat source side heat exchanger 20 operates the expansion valve 18 from the utilization side heat exchanger 62 as a condenser. It functions as an evaporator that heats and evaporates the refrigerant flowing therethrough.

  More specifically, the flow of the refrigerant when the refrigerant flows from the liquid refrigerant pipe 10 d toward the first gas refrigerant pipe 10 c (during the heating operation) in the heat source side heat exchanger 20 will be described.

  During the heating operation, the refrigerant (of gas-liquid two-phase) flowing from the liquid refrigerant pipe 10d into the heat source side heat exchanger 20 flows into the sub heat exchange unit 28 from the liquid side connection port 20b. The refrigerant heated by the auxiliary heat exchange unit 28 passes through the main pipe 26 and flows into the flow divider 25. During the heating operation, the refrigerant divided by the flow divider 25 flows into the first small diameter pipe 24a, the second small diameter pipe 24b, and the third small diameter pipe 24c. The refrigerants flowing into the first small diameter pipe 24a, the second small diameter pipe 24b and the third small diameter pipe 24c respectively flow into the first refrigerant flow passage 22a, the second refrigerant flow passage 22b and the third refrigerant flow passage 22c. . The refrigerant heated when passing through the first refrigerant flow passage 22a, the second refrigerant flow passage 22b, and the third refrigerant flow passage 22c flows into the internal space of the header 21 through the header communication pipe 21a. The refrigerant that has flowed into the internal space of the header 21 flows into the first gas refrigerant pipe 10 c from the gas side connection port 20 a of the heat source side heat exchanger 20.

(2-2-4) Expansion Valve The expansion valve 18 is an electric expansion valve capable of adjusting the opening degree which adjusts the flow rate of the refrigerant flowing through the heat source side heat exchanger 20 and the like. The expansion valve 18 is provided to the liquid refrigerant pipe 10d. The opening degree of the expansion valve 18 is controlled by a controller 70 described later.

(2-2-5) Accumulator The accumulator 16 is a container having a gas-liquid separation function that divides the inflowing refrigerant into a gas refrigerant and a liquid refrigerant. The accumulator 16 is disposed upstream of the compressor 12 in the refrigerant flow direction (see FIG. 1). The accumulator 16 is provided in the suction pipe 10 a through which the refrigerant flows to the suction side of the compressor 12. The refrigerant flowing into the accumulator 16 is divided into a gas refrigerant and a liquid refrigerant, and the gas refrigerant collected in the upper space flows out to the compressor 12.

(2-2-6) Bridge Circuit The bridge circuit 32 is a mechanism for controlling the flow direction of the refrigerant. The bridge circuit 32 includes a first check valve 32a, a second check valve 32b, a third check valve 32c, and a fourth check valve 32d (see FIG. 1).

  The first check valve 32 a is a valve that allows the flow of the refrigerant from the expansion valve 18 side to the liquid refrigerant communication pipe 46 side but does not allow the flow in the opposite direction. The second check valve 32 b is a valve that allows the flow of the refrigerant from the expansion valve 18 side to the heat source side heat exchanger 20 side but does not allow the flow in the opposite direction. The third check valve 32c is a valve that allows the flow of the refrigerant that flows from the liquid refrigerant communication pipe 46 side to the expansion valve 18 through the economizer heat exchanger 34, and does not allow the flow in the opposite direction. The fourth check valve 32d is a valve that allows the flow of the refrigerant that flows from the heat source side heat exchanger 20 side to the expansion valve 18 through the economizer heat exchanger 34, but does not allow the flow in the opposite direction.

  In the bridge circuit 32 configured in this manner, during the cooling operation, the refrigerant flows from the heat source side heat exchanger 20 through the fourth check valve 32 d to the expansion valve 18, and further the first check valve 32 a The refrigerant flows to the liquid refrigerant communication pipe 46. Further, in the bridge circuit 32 configured in this way, during the heating operation, the refrigerant flows from the liquid refrigerant communication pipe 46 through the third check valve 32 c to the expansion valve 18, and further the second check valve 32 b The refrigerant flows to the heat source side heat exchanger 20 through

(2-2-7) Economizer Heat Exchanger and Injection Valve The economizer heat exchanger 34 is a heat exchanger such as a double pipe heat exchanger or a plate heat exchanger, for example. The economizer heat exchanger 34 has a first flow passage 34a and a second flow passage 34b (see FIG. 1), and the refrigerant flowing in the first flow passage 34a exchanges heat with the refrigerant flowing in the second flow passage 34b. It has become.

  The first flow path 34 a constitutes a part of a refrigerant flow path in which the refrigerant flows from the bridge circuit 32 toward the expansion valve 18. In the first flow passage 34a, the refrigerant flowing to the expansion valve 18 passes through the third check valve 32c or the fourth check valve 32d of the bridge circuit 32.

  The second flow passage 34 b constitutes a part of the injection flow passage 35. The injection flow passage 35 is a refrigerant flow passage which branches from a refrigerant pipe in which the refrigerant flows from the bridge circuit 32 toward the expansion valve 18 and communicates with a compression chamber (not shown) in the process of compression of the compression mechanism of the compressor 12. is there. In the second flow path 34b, the third check valve 32c or the fourth check valve 32d of the bridge circuit 32 is passed, and the refrigerant flow branches from the bridge circuit 32 toward the expansion valve 18 and branched from the refrigerant flow path. The refrigerant flows to the compressor 12 through the valve 36.

  The injection valve 36 is, for example, a motorized valve capable of adjusting the opening degree. The injection valve 36 is provided in a pipe that connects the refrigerant flow path in which the refrigerant flows from the bridge circuit 32 toward the expansion valve 18 and the second flow path 34 b of the economizer heat exchanger 34.

  When the injection valve 36 is opened, the refrigerant branched from the refrigerant flow path in which the refrigerant flows from the bridge circuit 32 toward the expansion valve 18 flows into the second flow path 34 b of the economizer heat exchanger 34. Then, the refrigerant flowing into the second flow passage 34 b exchanges heat with the refrigerant flowing through the first flow passage 34 a and becomes a gas phase refrigerant and is supplied to the compression chamber in the middle of compression of the compression mechanism of the compressor 12.

  As the injection valve 36, a solenoid valve capable of controlling only the opening / closing may be used instead of the motor-operated valve whose opening degree can be adjusted. When a solenoid valve is used as the injection valve 36, it is preferable that a capillary be provided in the injection flow channel 35.

(2-2-8) Heat source side fan The heat source side fan 30 sucks the outdoor air into the heat source unit 10 and supplies it to the heat source side heat exchanger 20, and the air heat-exchanged with the refrigerant in the heat source side heat exchanger 20 It is a fan that discharges outside the room. That is, the heat source side fan 30 is a fan that supplies the heat source side heat exchanger 20 with outdoor air as a cooling source or a heating source of the refrigerant flowing through the heat source side heat exchanger 20. The heat source side fan 30 is, for example, an axial flow fan such as a propeller fan. However, the type of fan is not limited to the axial fan, and may be appropriately selected. The heat source side fan 30 is driven by a fan motor 30a (see FIG. 1).

(2-2-9) Sensor The heat source unit 10 is provided with various sensors. For example, the heat source unit 10 has the following sensors. In addition, the following temperature sensors and pressure sensors should just be sensors which can measure desired temperature and pressure, and the kind of sensor should just be selected suitably.

  The heat source unit 10 has a suction temperature sensor 92a that measures the suction temperature Ts of the compressor 12 (see FIG. 1). The heat source unit 10 also has a discharge pressure sensor 94 that measures the discharge pressure Pd of the compressor 12 (see FIG. 1). The heat source unit 10 also has a discharge temperature sensor 92b that measures the discharge temperature Td of the compressor 12 (see FIG. 1).

  The heat source unit 10 further includes a first temperature sensor 92c and a second temperature sensor 92d (see FIG. 1). The first temperature sensor 92c and the second temperature sensor 92d are, for example, thermistors, although the types are not limited.

  The first temperature sensor 92 c is an example of a first thermometer side. When the heat source side heat exchanger 20 is used as a condenser (during cooling operation), the first temperature sensor 92 c is the flow divider 25 (pressure loss portion) of the heat source side heat exchanger 20 in the flow direction A of the refrigerant On the more upstream side, the temperature of the refrigerant flowing through the heat source side heat exchanger 20 is measured as a first temperature T1. Conversely, when the heat source side heat exchanger 20 is used as an evaporator (during heating operation), the heat source side heat exchange downstream of the flow divider 25 of the heat source side heat exchanger 20 in the flow direction of the refrigerant The temperature of the refrigerant flowing through the vessel 20 is measured.

  The first temperature sensor 92c is preferably located at the center of the main heat exchange section 22 disposed upstream of the flow divider 25 in the refrigerant flow direction A when the heat source side heat exchanger 20 is used as a condenser (see FIG. In 1, the temperature of the refrigerant flowing downstream of the alternate long and short dash line C and upstream of the flow divider 25 is measured.

  Further, preferably, the first temperature sensor 92c is, in the refrigerant flow path of the heat source side heat exchanger 20, an inlet of the condenser in the refrigerant flow direction A when the heat source side heat exchanger 20 is used as a condenser. The temperature of the refrigerant flowing downstream from the center of the condenser (shown by the alternate long and short dash line M1 in FIG. 1) with the outlet of the condenser is measured. Here, the inlet of the condenser means the gas side connection port 20a to which the first gas refrigerant pipe 10c provided in the header 21 is connected. The outlet of the condenser means the liquid side connection port 20 b provided in the auxiliary heat exchange unit 28.

  More preferably, the first temperature sensor 92c is a main heat exchange unit 22 disposed upstream of the flow divider 25 in the flow direction A of the refrigerant when the heat source side heat exchanger 20 is used as a condenser. The temperature of the refrigerant flowing through one of a plurality of pipes (small diameter tubes 24) connecting the flow splitter 25 and the flow divider 25 is measured. Furthermore, preferably, in the flow direction A of the refrigerant when the heat source side heat exchanger 20 is used as a condenser, the first temperature sensor 92c preferably includes the main heat exchange portion 22 and the flow divider 25 of the small diameter pipe 24. The temperature of the refrigerant flowing downstream of the center (indicated by the alternate long and short dash line N in FIG. 1) of the above is measured. In addition, preferably, the first temperature sensor 92c has a small diameter connected to the main heat exchange portion 22 (the first refrigerant flow passage 22a, the second refrigerant flow passage 22b, and the third refrigerant flow passage 22c) at different heights. The temperature of the refrigerant flowing through the first small diameter pipe 24 a connected to the main heat exchange portion 22 at the lowest position in the pipe 24 (that is, connected to the first refrigerant flow path 22 a) is measured.

  Although the refrigerant temperature measurement position of the first temperature sensor 92c is not limited, in the embodiment depicted in FIG. 1, the first temperature sensor 92c is a heat source side heat exchanger 20 of the first small diameter tube 24a. It is attached to the downstream side from the center (dashed-dotted line N) of the main heat exchange section 22 and the flow divider 25 in the flow direction A of the refrigerant when used as a tank. Then, the first temperature sensor 92c measures the temperature of the refrigerant flowing through the first small diameter tube 24a at the mounting position of the first temperature sensor 92c. That is, in the embodiment depicted in FIG. 1, the first temperature sensor 92c is attached near the flow divider 25 of the first small diameter tube 24a, and measures the temperature of the refrigerant flowing through the first small diameter tube 24a at the mounting position. .

  The second temperature sensor 92 d is an example of a second thermometer side. When the heat source side heat exchanger 20 is used as a condenser (during cooling operation), the second temperature sensor 92 d is the flow divider 25 (pressure loss portion) of the heat source side heat exchanger 20 in the flow direction A of the refrigerant The refrigerant temperature on the more downstream side and on the upstream side than the expansion valve 18 is measured as a second temperature T2.

  Although the refrigerant temperature measurement position of the second temperature sensor 92d is not limited, in the embodiment depicted in FIG. 1, the second temperature sensor 92d is a heat source side heat exchanger in the flow direction A of the refrigerant during the cooling operation. The temperature of the refrigerant flowing through the liquid refrigerant pipe 10d on the downstream side of the twenty flow dividers 25 (pressure loss portion) and on the upstream side of the expansion valve 18 is measured as a second temperature T2.

  Further, the heat source unit 10 is disposed between the bridge circuit 32 and the liquid side shut-off valve 42 in the liquid refrigerant pipe 10d (the downstream side of the first check valve 32a and the upstream side of the third check valve 32c in the bridge circuit 32). And a liquid pipe side temperature sensor 92e provided in the pipe connecting the liquid side shut-off valve 42). The liquid pipe side temperature sensor 92 e measures the temperature Tlp of the refrigerant sent from the bridge circuit 32 to the liquid refrigerant communication pipe 46 or the refrigerant sent from the liquid refrigerant communication pipe 46 to the bridge circuit 32.

  In the heat source unit 10, an external air temperature sensor 96 is provided around the heat source side heat exchanger 20 or the heat source side fan 30 to measure the temperature Toa of the outdoor air drawn into the heat source unit 10.

(2-2-10) Heat source side control unit The heat source side control unit 72 controls the operation of each unit constituting the heat source unit 10. The heat source side control unit 72 includes a microcomputer, a memory, and the like provided to control the heat source unit 10. The heat source side control unit 72 is configured to be able to exchange control signals and the like with the use side control unit 74 of the use unit 60 via the communication line.

  The heat source side control unit 72 of the heat source unit 10 and the use side control unit 74 of the usage unit 60 are communicably connected via a communication line to control the controller 70 that controls the entire operation of the refrigerant cycle apparatus 100. Configured. The controller 70 controls the overall operation of the refrigerant cycle apparatus 100 by the microcomputer executing a program stored in the memory.

  The controller 70 of the present embodiment is merely an example of the control device of the refrigerant cycle device 100. The controller may realize the same function as the function exhibited by the controller 70 of the present embodiment by hardware such as a logic circuit or may be realized by a combination of hardware and software.

  As shown in FIG. 2, the controller 70 is connected so as to be able to receive measurement signals of the temperature sensors 92 a to 92 e for measuring the temperature of the refrigerant, the discharge pressure sensor 94 and the outside air temperature sensor 96. The controller 70 can control the compressor 12, the switching mechanism 14, the expansion valve 18, the heat source side fan 30, the injection valve 36, the use side fan 66, and the like based on measurement signals of sensors, etc. 12, 14, 18, 30, 36, 66 are connected.

  The controller 70 condenses the heat source side heat exchanger 20 in the refrigerant cycle device 100 by controlling the compressor 12, the switching mechanism 14, the expansion valve 18, the heat source side fan 30, the injection valve 36, the use side fan 66 and the like. A cooling operation that causes the use-side heat exchanger 62 to function as an evaporator, and a heating operation that causes the heat-source-side heat exchanger 20 to function as an evaporator and the use-side heat exchanger 62 to function as a condenser are performed.

(3) Operation at the time of cooling operation / heating operation of refrigerant cycle device The operation at the time of cooling operation / heating operation of the refrigerant cycle device 100 controlled by the controller 70 will be described.

(3-1) Cooling Operation When a cooling operation is instructed by an instruction from a remote control (not shown) or the like, the controller 70 causes the refrigerant circuit 80 to be in the cooling operation state (the switching mechanism 14 is shown by a solid line in FIG. 1). Control the switching mechanism 14 so that Further, the controller 70 controls the operation of the compressor 12, the heat source fan 30 and the user fan 66 based on the measurement signal of the sensor and the like. Further, the controller 70 controls the operation of the expansion valve 18 and the injection valve 36 so as to perform a predetermined operation based on a measurement signal of a sensor or the like. The control of the expansion valve 18 by the controller 70 during the cooling operation will be separately described later.

  As a result of controlling the operation of the refrigerant cycle device 100 in this manner, the low pressure gas refrigerant in the refrigerant circuit 80 is drawn into the compressor 12 and compressed to become a high pressure gas refrigerant. The gas refrigerant compressed by the compressor 12 is sent to the heat source side heat exchanger 20 through the switching mechanism 14.

  The high-pressure gas refrigerant sent to the heat source side heat exchanger 20 exchanges heat with the outdoor air supplied by the heat source side fan 30 in the heat source side heat exchanger 20 functioning as a condenser, and is cooled and condensed. , High pressure liquid refrigerant. The liquid refrigerant condensed in the heat source side heat exchanger 20 is sent to the economizer heat exchanger 34 to be further cooled, decompressed and expanded by the expansion valve 18, and utilized through the liquid side shut-off valve 42 and the liquid refrigerant communication pipe 46 It is sent to the unit 60. Note that part of the liquid refrigerant flowing through the liquid refrigerant pipe 10 d is divided into the injection flow channel 35, and the pressure is reduced by the injection valve 36. Then, the refrigerant decompressed by the injection valve 36 is sent to the economizer heat exchanger 34, exchanges heat with the high-pressure liquid refrigerant flowing through the liquid refrigerant pipe 10d, and is evaporated by being heated. It injects into the compression chamber in the middle of compression of a compression mechanism.

  The refrigerant sent to the use unit 60 is sent to the use side heat exchanger 62. The low-pressure gas-liquid two-phase refrigerant sent to the use-side heat exchanger 62 exchanges heat with room air supplied by the use-side fan 66 in the use-side heat exchanger 62 functioning as a refrigerant evaporator. By heating and heating, it evaporates and becomes a low pressure gas refrigerant. The low pressure gas refrigerant is sent from the utilization unit 60 to the heat source unit 10 through the gas refrigerant communication pipe 48.

  The low-pressure gas refrigerant sent to the heat source unit 10 is again sucked into the compressor 12 through the gas side closing valve 44 and the switching mechanism 14.

(3-2) Heating Operation When a heating operation is instructed by an instruction from a remote control (not shown) or the like, the controller 70 causes the refrigerant circuit 80 to be in the heating operation state (the switching mechanism 14 is shown by a broken line in FIG. 1). Control the switching mechanism 14 so that Further, the controller 70 controls the operation of the compressor 12, the heat source fan 30 and the user fan 66 based on the measurement signal of the sensor and the like. Further, the controller 70 controls the operation of the expansion valve 18 and the injection valve 36 so as to perform a predetermined operation based on a measurement signal of a sensor or the like.

  As a result of controlling the operation of the refrigerant cycle device 100 in this manner, the low pressure gas refrigerant in the refrigerant circuit 80 is drawn into the compressor 12 and compressed to become a high pressure gas refrigerant. The gas refrigerant compressed by the compressor 12 is sent from the heat source unit 10 to the utilization unit 60 through the switching mechanism 14, the gas side closing valve 44 and the gas refrigerant communication pipe 48.

  The high-pressure gas refrigerant sent to the usage unit 60 is sent to the usage-side heat exchanger 62. The high-pressure gas refrigerant sent to the use-side heat exchanger 62 exchanges heat with room air supplied by the use-side fan 66 in the use-side heat exchanger 62 functioning as a condenser, and is cooled and condensed. , High pressure liquid refrigerant. The high pressure liquid refrigerant is sent from the utilization unit 60 to the heat source unit 10 through the liquid refrigerant communication pipe 46.

  The refrigerant sent to the heat source unit 10 is sent to the expansion valve 18 through the liquid side shut-off valve 42 and the economizer heat exchanger 34, and the pressure is reduced by the expansion valve 18 so that the low-pressure gas-liquid two-phase refrigerant and Become. The low-pressure gas-liquid two-phase refrigerant is sent to the heat source side heat exchanger 20.

  The low-pressure gas-liquid two-phase refrigerant sent to the heat source side heat exchanger 20 exchanges heat with the outdoor air supplied by the heat source side fan 30 in the heat source side heat exchanger 20 functioning as a refrigerant evaporator. By being heated, it evaporates and becomes a low pressure gas refrigerant. The low pressure gas refrigerant is again drawn into the compressor 12 through the switching mechanism 14.

(4) Control of Expansion Valve During Cooling Operation of Refrigerant Cycle Device During the cooling operation, the controller 70 measures the first temperature T1 measured by the first temperature sensor 92c and the second temperature T2 measured by the second temperature sensor 92d. And adjust the opening degree of the expansion valve 18. Specifically, the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature T1, the second temperature T2 and the condensation temperature Tc in the refrigeration cycle. More specifically, the controller 70 adjusts the opening degree of the expansion valve 18 based on a first temperature difference D1 and a second temperature difference D2 described later.

  The adjustment of the opening degree of the expansion valve by the controller 70 will be described in detail below.

  The controller 70 calculates a first temperature difference D1 and a second temperature difference D2 that are used to control the operation of the expansion valve 18 as one function related to adjusting the opening degree of the expansion valve. The first temperature difference D1 is a temperature difference between the first temperature T1 measured by the first temperature sensor 92c and the condensation temperature Tc in the heat source side heat exchanger 20 which is a condenser. The second temperature difference D2 is a temperature difference between the first temperature T1 measured by the first temperature sensor 92c and the condensation temperature Tc in the heat source side heat exchanger 20 which is a condenser.

  For example, the controller 70 calculates the first temperature difference D1 and the second temperature difference D2 as follows.

  The controller 70 first calculates the condensation temperature Tc based on the discharge pressure Pd measured by the discharge pressure sensor 94. Specifically, the controller 70 calculates the condensation temperature Tc from the pressure measured by the discharge pressure sensor 94 using, for example, a table indicating the correlation between the pressure stored in the memory and the condensation temperature. Note that the method of calculating the condensation temperature Tc is merely an example, and the controller 70 condenses from the discharge pressure Pd measured by the discharge pressure sensor 94 using, for example, the relational expression between the pressure and the condensation temperature stored in the memory. The temperature Tc may be calculated.

  The condensation temperature Tc does not have to be calculated by the controller 70 based on the discharge pressure Pd measured by the discharge pressure sensor 94. The condensation temperature Tc may be measured by a temperature sensor such as a thermistor provided in the heat source side heat exchanger 20 separately from the first temperature sensor 92c and the second temperature sensor 92d. The temperature sensor that measures the condensation temperature Tc is, for example, a temperature sensor that measures the temperature of the refrigerant flowing through the heat source side heat exchanger 20 upstream of the first temperature sensor 92c in the flow direction A of the refrigerant during cooling operation . The temperature sensor for measuring the condensation temperature Tc is provided, for example, at the center of the main heat exchange section 22 or upstream of the center of the main heat exchange section 22 in the flow direction A of the refrigerant during the cooling operation. measure.

  When the condensation temperature Tc is calculated, the controller 70 subtracts the first temperature T1 measured by the first temperature sensor 92c from the condensation temperature Tc to calculate the first temperature difference D1. Further, the controller 70 subtracts the second temperature T2 measured by the second temperature sensor 92d from the condensation temperature Tc to calculate the second temperature difference D2.

  The reason why the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1 and the second temperature difference D2 will be described.

  It is assumed that, during the cooling operation, the controller 70 controls the operation of each part of the refrigerant cycle apparatus 100 so as to realize the refrigeration cycle schematically drawn by the solid line in FIG. 3. Here, in order to simplify the description, the injection (intermediate injection) to the compression chamber in the middle of compression of the compression mechanism of the compressor 12 will not be considered.

  In the refrigerant cycle device 100 of the present embodiment, the controller 70 controls the expansion valve 18 according to the degree of subcooling during the cooling operation. The controller 70 reduces the opening degree of the expansion valve 18 when the degree of subcooling is smaller than a predetermined target value, and increases the degree of opening of the expansion valve 18 when the degree of subcooling is larger than the target value. Control.

  In the heat source side heat exchanger 20 as a condenser, when the flash gas is not generated and the refrigerant is condensed to be a liquid phase refrigerant, the value of the second temperature difference D2 is approximately equal to the degree of supercooling Become. Therefore, when flash gas is not generated in the heat source side heat exchanger 20, the controller 70 adjusts the degree of opening of the expansion valve 18 based on the second temperature difference D2 to obtain the degree of supercooling, as shown in FIG. The refrigerant cycle apparatus 100 can be operated to realize the refrigeration cycle shown in FIG.

  However, in the case where the flash gas is generated in the pressure loss portion (in the present embodiment, the flow divider 25) of the heat source side heat exchanger 20, the second temperature T2 measured by the second temperature sensor 92d is The temperature of the refrigerant is as shown by the black circle in 3 and is lower than the condensation temperature. Therefore, when the second temperature difference D2 is used as the degree of subcooling, the refrigerant having the degree of subcooling despite the fact that the refrigerant is not actually the subcoolant at the temperature measurement position of the second temperature sensor 92d. It will be misidentified as Then, assuming that the controller 70 adjusts the opening degree of the expansion valve 18 based on the second temperature difference D2, it becomes difficult to realize a desired refrigeration cycle as depicted in FIG. 3. In particular, when the second temperature difference D2 is used as the degree of subcooling, if the calculated second temperature difference D2 is larger than the target value, control is performed so as to increase the opening degree of the expansion valve 18, Such control does not eliminate the generation of the flash gas, and it becomes difficult to realize the desired refrigeration cycle as depicted in FIG.

  Now, at the position where the first temperature sensor 92c measures the temperature, in other words, on the upstream side of the pressure loss portion (in the present embodiment, the flow divider 25), the pressure drop is small, and flash gas is less likely to be generated. Therefore, if the first temperature difference D1 is regarded as the degree of supercooling and the first temperature difference D1 is controlled to be the target value, it can be expected that the refrigerant becomes the supercooling liquid at the outlet of the heat source side heat exchanger 20 . That is, if the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1, the opening degree adjustment of the expansion valve 18 in a state where the temperature decrease of the refrigerant due to the generation of the flash gas is mistaken as the supercooling state. Occurrence of situations in which

  However, on the other hand, since the first temperature T1 is the temperature of the refrigerant flowing through one of the plurality of refrigerant channels 22a to 22c of the main heat exchange portion 22, the temperature T1 is the temperature with the temperature of the refrigerant after merging by the flow divider 25 There may be a difference between them. Therefore, when only the first temperature difference D1 is used, it may be difficult to accurately realize the desired refrigeration cycle as depicted in FIG. 3.

  In contrast, in the refrigerant cycle device 100, the opening degree of the expansion valve 18 is adjusted using both the first temperature difference D1 and the second temperature difference D2, so even if the flash gas is generated in the pressure loss portion. It is possible to suppress the opening adjustment of the expansion valve 18 in the state that the temperature decrease of the refrigerant due to the generation of the flash gas is misunderstood as the supercooling state, and conversely, the generation of the flash gas does not occur in the pressure loss portion In the state where it does not easily occur, the degree of supercooling can be controlled with high accuracy by adjusting the opening degree of the expansion valve 18.

  Specifically, for example, the controller 70 selects one of the first temperature difference D1 and the second temperature difference D2 based on the first temperature T1 and the second temperature T2, and the expansion valve based on the selected temperature difference. Adjust the opening degree of 18. More specifically, for example, the controller 70 compares the first temperature difference D1 with the second temperature difference D2, and selects one of the first temperature difference D1 and the second temperature difference D2 based on the comparison result, The opening degree of the expansion valve 18 is adjusted based on the selected temperature difference.

  An example of the opening degree control of the expansion valve 18 by the controller 70 will be described in detail below with reference to the flowcharts of FIGS. 4 and 5.

  Here, as shown in FIG. 1, the first temperature T1 is the temperature of the refrigerant flowing through the first small diameter pipe 24 a in the vicinity of the pressure loss portion (here, the flow divider 25). In the main heat exchange portion 22, due to the influence of gravity, the temperature of the refrigerant flowing through the first refrigerant flow passage 22a is likely to be lower than the temperature of the refrigerant flowing through the refrigerant flow passages 22b and 22c above it. That is, the first temperature T1 tends to be a smaller value than the refrigerant temperature after the refrigerant channels 22a to 22c merge.

  The controller 70 is based on the first temperature T1 measured by the first temperature sensor 92c, the second temperature T2 measured by the second temperature sensor 92d, and the pressure measured by the pressure sensor 94 during the cooling operation. The first temperature difference D1 and the second temperature difference D2 are calculated (step S1).

  Next, the controller 70 compares the first temperature difference D1 with the second temperature difference D2, and selects one of the first temperature difference D1 and the second temperature difference D2 based on the comparison result (step S2).

  Specifically, as in step S21 of the flowchart of FIG. 4 that describes step S2 in detail, the controller 70 determines whether the first temperature difference D1 is smaller than α times the second temperature difference D2 (α> 0). Calculate the

  For example, the value of α is 1. When the value of α is 1, the controller 70 determines whether or not the first temperature difference D1 is equal to or less than the second temperature difference D2 in step S21. Then, the controller 70 expands the first temperature difference D1 if the first temperature difference D1 is equal to or less than the second temperature difference D2, and expands the second temperature difference D2 if the first temperature difference D1 is larger than the second temperature difference D2. The temperature difference used to adjust the opening degree of the valve 18 is selected (see step S22 and step S23).

  Then, the controller 70 adjusts the opening degree of the expansion valve 18 based on the selected one of the temperature differences (step S3). Specifically, the controller 70 reduces the opening degree of the expansion valve 18 when the selected temperature difference is smaller than the predetermined target value, and the expansion valve 18 when the selected temperature difference is larger than the target value. Control to increase the opening degree of

  The controller 70 returns to step S1 and repeatedly executes a series of processes.

  Further description will be given by taking a specific example.

  For example, as a result of the calculation process in step S1, the value of the first temperature difference D1 is a relatively small value (eg, + 1 ° C.), and the value of the second temperature difference D2 is a relatively large target degree of supercooling (eg, + 5 ° C.) )) (Eg, + 7 ° C.).

  As described above, the first temperature T1 is characterized in that the temperature tends to be smaller than the temperature of the refrigerant (the temperature of the entire refrigerant passing through the main heat exchange section 22) after the refrigerant channels 22a to 22c merge. Therefore, if the flash gas is not generated in the pressure loss portion, the first temperature difference D1 tends to be a larger value than the second temperature difference D2. Therefore, if the value of the second temperature difference D2 is larger than the value of the first temperature difference D1, the second temperature difference D2 is considered to be a relatively large value due to the generation of the flash gas in the pressure loss portion.

  In a situation where the value of the first temperature difference D1 is relatively small and the value of the second temperature difference D2 is larger than the target degree of supercooling, the opening temperature adjustment of the expansion valve 18 is provisionally used for the second temperature difference D2 If the second temperature difference D2 becomes smaller, the expansion valve 18 is controlled to increase the opening degree. In such control of the expansion valve 18, the situation where the flash gas is generated in the pressure loss portion is difficult to eliminate.

  On the other hand, in the refrigerant cycle device 100, the controller 70 compares the first temperature difference D1 with the second temperature difference D2 in step S2, and the value of the first temperature difference D1 (for example, + 1.degree. C.) <Second The first temperature difference D1 is selected as the temperature difference used to control the opening degree of the expansion valve 18 because the temperature difference D2 (for example, + 7 ° C.).

  Then, in step S3, the controller 70 adjusts the opening degree of the expansion valve 18 so that the first temperature difference D1 becomes the target degree of subcooling (for example, + 5 ° C.). The controller 70 controls the opening degree of the expansion valve 18 to be smaller if the first temperature difference D1 is smaller than the target degree of subcooling. As a result, even if the flash gas is generated in the pressure loss portion, such a situation is likely to be resolved. Here, the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1, so that the first temperature difference D1 approaches (increases) the target degree of subcooling. On the other hand, since the second temperature T2 is raised by suppressing the generation of the flash gas, the second temperature difference D2 is dropped at one end.

  By the way, as described above, the first temperature T1 measured in the present embodiment is lower than the refrigerant temperature (the temperature of the entire refrigerant passing through the main heat exchange section 22) after the refrigerant channels 22a to 22c merge. It has the characteristic of being easy to become a value. Therefore, even if the first temperature difference D1 becomes the target degree of subcooling, it is conceivable that the actual degree of subcooling (degree of subcooling of the combined refrigerant) is only a value smaller than the target degree of subcooling .

  On the other hand, here, when the second temperature difference D2 becomes lower than the first temperature difference D1 (in other words, when it is determined that the generation of the flash gas is eliminated), the controller 70 determines the second temperature difference in step S2. D2 is selected, and the opening degree of the expansion valve 18 is controlled based on the second temperature difference D2 in step S3. Therefore, the controller 70 can accurately control the degree of subcooling to the target degree of subcooling.

  Here, although the case where the value of α used in the process of step S21 is 1 has been described as an example, the value of α is not limited to 1. For example, an appropriate value of α is derived which can discriminate between the state where the flash gas is generated and the state where the flash gas is not generated in the heat source side heat exchanger 20 which is a condenser. It may be used in processing. For example, the temperature of the refrigerant flowing through the second small diameter tube 24b is measured as the first temperature T1, and the value of the first temperature difference D1 is the second temperature difference even if the flash gas is not generated. When there is a relation that it tends to be smaller than the value of D2, it is conceivable to use a value smaller than 1 as the value of α.

(5) Characteristics (5-1)
The refrigerant cycle device 100 according to the above embodiment includes a refrigerant circuit 80, a first temperature sensor 92c as an example of a first temperature measurement unit, a second temperature sensor 92d as an example of a second temperature measurement unit, and a calculation unit. And a controller 70 as an example of a control unit. The refrigerant circuit 80 has a compressor 12, a condenser (in the embodiment, the heat source side heat exchanger 20), an expansion valve 18, and an evaporator (in the embodiment, the use side heat exchanger 62). The compressor 12 compresses the refrigerant. The condenser cools and condenses the refrigerant compressed by the compressor 12. The expansion valve 18 depressurizes the refrigerant condensed by the condenser. The evaporator heats and evaporates the refrigerant flowing from the condenser through the expansion valve 18. The first temperature sensor 92c is a pressure loss portion (a branch in this embodiment) of the condenser in the flow direction of the refrigerant (here, the flow direction of the refrigerant during the cooling operation and the flow direction indicated by the arrow A in FIG. 1). Upstream from the vessel 25), the temperature of the refrigerant flowing through the condenser is measured as a first temperature T1. The second temperature sensor 92d measures, as a second temperature T2, a refrigerant temperature downstream of the pressure loss portion and upstream of the expansion valve 18 in the refrigerant flow direction. The controller 70 calculates the temperature difference between the first temperature T1 and the condensation temperature Tc in the condenser as the first temperature difference D1, and the temperature difference between the second temperature T2 and the condensation temperature Tc as the second temperature difference D2. . The controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1 and the second temperature difference D2.

  The first temperature T1 of the refrigerant is measured on the upstream side of the pressure loss portion of the condenser, and therefore, is not susceptible to the generation of the flash gas in the pressure loss portion. On the other hand, since the second temperature T2 of the refrigerant is measured on the downstream side of the pressure loss portion of the condenser, it is susceptible to the generation of the flash gas in the pressure loss portion. However, by measuring the second temperature T2 downstream of the measurement position of the first temperature T1, a value close to the temperature of the refrigerant flowing out from the outlet of the condenser can be obtained.

  In the refrigerant cycle device 100, the temperature differences D1 and D2 between the first temperature T1 and the second temperature T2 characterized as described above and the condensation temperature Tc are calculated, respectively, and used to adjust the opening degree of the expansion valve 18. Be done. Therefore, even if the flash gas is generated in the pressure loss portion, it is possible to suppress that the opening degree adjustment of the expansion valve 18 is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is misunderstood as the supercooling state. On the other hand, in the state where flash gas is not generated / hard to generate in the pressure loss portion, the temperature difference between the second temperature T2 and the condensation temperature Tc (second temperature difference D2) The control of the expansion valve 18 can be accurately performed so that the difference between the temperature and the condensation temperature becomes a predetermined value.

(5-2)
In the refrigerant cycle device 100 according to the above embodiment, the controller 70 selects one of the first temperature difference D1 and the second temperature difference D2 based on the first temperature T1 and the second temperature T2, and selects the selected temperature difference. The opening degree adjustment of the expansion valve 18 is performed based on it.

  In the refrigerant cycle device 100, a temperature difference that is not affected by the generation of the flash gas in the pressure loss portion can be selected based on the first temperature T1 and the second temperature T2 and can be used for control. Therefore, it can be suppressed that the opening degree adjustment of the expansion valve 18 is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is mistaken as the overcooling state. In addition, when it is determined that the flash gas is not generated in the pressure loss portion based on the first temperature T1 and the second temperature T2, a temperature difference between the second temperature T2 and the condensation temperature Tc (second temperature difference D2 Control of the expansion valve 18 can be performed with high accuracy.

(5-3)
In the refrigerant cycle device 100 according to the above embodiment, the controller 70 compares the first temperature difference D1 with the second temperature difference D2, and based on the comparison result, selects one of the first temperature difference D1 and the second temperature difference D2. The opening degree of the expansion valve 18 is adjusted based on the selected temperature difference.

  In the refrigerant cycle apparatus 100, based on the comparison result of the first temperature difference D1 and the second temperature difference D2, a temperature difference not influenced by the generation of the flash gas in the pressure loss portion is selected, and this is selected for control. It can be used. Therefore, it can be suppressed that the opening degree adjustment of the expansion valve 18 is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is mistaken as the overcooling state. In addition, when it is determined that the flash gas is not generated in the pressure loss portion based on the comparison result of the first temperature difference D1 and the second temperature difference D2, the temperature difference between the second temperature T2 and the condensation temperature Tc ( The control of the expansion valve 18 can be accurately performed using the second temperature difference D2).

(5-4)
In the refrigerant cycle device 100 according to the embodiment, the controller 70 selects the smaller one of the first temperature difference D1 and the second temperature difference D2, and adjusts the opening degree of the expansion valve 18 based on the selected temperature difference.

  Here, by using the smaller value of the first temperature difference D1 and the second temperature difference D2 for adjusting the opening degree of the expansion valve 18, a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is misidentified as a supercooling state It can suppress that opening degree adjustment of expansion valve 18 is performed. In addition, when it is determined that no flash gas is generated in the pressure loss portion, the temperature difference between the second temperature T2 and the condensation temperature Tc (second temperature difference D2) is used to control the expansion valve 18 accurately. It can be carried out.

(5-5)
In the refrigerant cycle device 100 according to the above-described embodiment, the flow divider 25 as an example of the pressure loss portion is a merging portion of the refrigerant flow path in the flow direction A of the refrigerant.

  Here, it can be suppressed that the opening degree adjustment of the expansion valve 18 is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is misidentified as the overcooling state.

(5-6)
In the refrigerant cycle device 100 according to the embodiment, the flow divider 25 as an example of the pressure loss portion is a reduction portion of the refrigerant flow area.

  Here, it can be suppressed that the opening degree adjustment of the expansion valve 18 is performed in a state in which the temperature decrease of the refrigerant due to the generation of the flash gas is misidentified as the overcooling state.

(5-7)
In the refrigerant cycle device 100 according to the above-described embodiment, the heat source side heat exchanger 20 as an example of a condenser causes the main heat exchange unit 22, the auxiliary heat exchange unit 28, and the refrigerant flowing through the main heat exchange unit 22 to merge. And a flow divider 25 as an example of a connection leading to the secondary heat exchange unit 28. The pressure loss part is a connection part.

  Here, even if the flash gas is generated at the connection portion between the main heat exchange unit 22 and the sub heat exchange unit 28, the expansion valve 18 is opened in a state where the temperature decrease of the refrigerant due to the generation of the flash gas is misunderstood as the supercooling state. It can suppress that the degree adjustment is performed.

(5-8)
In the refrigerant cycle device 100 according to the above-described embodiment, the first temperature sensor 92c includes the inlet of the condenser (gas side connection port 20a) and the outlet of the condenser (liquid side connection port 20b) in the refrigerant flow path of the condenser. Measure the temperature of the refrigerant flowing downstream of the center of the

  Here, the temperature of the subcooled liquid refrigerant can be measured as the first temperature T1.

(5-9)
In the refrigerant cycle device 100 according to the above-described embodiment, the heat source side heat exchanger 20 as an example of the condenser is heat exchange disposed upstream of the flow divider 25 as an example of the merging portion in the flow direction A of the refrigerant. It has a main heat exchange part 22 as an example of a part, and a plurality of pipes (small diameter pipe 24 in the present embodiment) connecting the main heat exchange part 22 and the junction part. The first temperature sensor 92 c measures the temperature of the refrigerant flowing downstream of the center of the main heat exchange section 22 in the refrigerant flow direction A.

  Here, the temperature of the subcooled liquid refrigerant can be measured as the first temperature T1.

(5-10)
In the refrigerant cycle device 100 according to the above embodiment, the first temperature sensor 92c measures the temperature of the refrigerant flowing through one of the small diameter tubes 24.

  Here, it is easy to measure the temperature of the subcooled liquid refrigerant as the first temperature T1.

(5-11)
In the refrigerant cycle device 100 according to the above-described embodiment, the first temperature sensor 92c is located downstream of the center of the main heat exchange portion 22 and the merging portion (divider 25) of the small diameter pipe 24 in the refrigerant flow direction A. Measure the temperature of the refrigerant flowing through the

  Here, it is easy to measure the temperature of the subcooled liquid refrigerant as the first temperature T1.

(5-12)
In the refrigerant cycle device 100 according to the above-described embodiment, the plurality of small diameter tubes 24 are connected to the main heat exchange unit 22 at different heights. The first temperature sensor 92 c measures the temperature of the refrigerant flowing through the small diameter pipe 24 (first small diameter pipe 24 a) connected to the main heat exchange unit 22 at the lowest position.

  Here, it is easy to measure the temperature of the subcooled liquid refrigerant as the first temperature T1.

(6) Modifications The modification of the said embodiment is shown below. In addition, one modification shown below may be combined suitably in the range which does not mutually contradict with one part or all part of the structure of the said embodiment and another modification.

(6-1) Modification A
In the above embodiment, the controller 70 compares the first temperature difference D1 with the second temperature difference D2, selects one of the first temperature difference D1 and the second temperature difference D2 based on the comparison result, and selects the selected temperature. The opening degree of the expansion valve 18 is adjusted based on the difference.

  However, the controller 70 does not compare the first temperature difference D1 and the second temperature difference D2 (without using the condensing temperature Tc in particular), and based on the first temperature T1 and the second temperature T2, One of the temperature difference D1 and the second temperature difference D2 may be selected, and the opening degree of the expansion valve 18 may be adjusted based on the selected temperature difference.

  For example, in the cooling operation of the refrigerant cycle apparatus 100, when a predetermined time has elapsed from the start of the refrigerant cycle apparatus 100, the first temperature T1 and the second temperature T2 are not generated in a situation where the flash gas is not generated. It is assumed that it is known that there is a predetermined relationship between For example, here, when the cooling operation of the refrigerant cycle apparatus 100 is performed and a predetermined time has elapsed since the activation of the refrigerant cycle apparatus 100, the first temperature T1 is the second temperature when the flash gas is not generated. It is assumed that it is known that there is a relationship below temperature T2.

  In such a case, the controller 70 is in the cooling operation of the refrigerant cycle apparatus 100, and has a relationship that the second temperature T2 is lower than the first temperature T1 after a predetermined time has elapsed since the activation of the refrigerant cycle apparatus 100. In this case, the first temperature difference D1 is selected, and the second temperature difference D2 is selected if the second temperature T2 is higher than the first temperature T1, and the opening degree of the expansion valve 18 is selected based on the selected temperature difference. Adjustments may be made.

(6-2) Modified Example B
In the above embodiment, the controller 70 selects one of the first temperature difference D1 and the second temperature difference D2 based on the first temperature T1 and the second temperature T2, and selects one of the expansion valve 18 based on the selected temperature difference. Adjust the opening degree. However, instead of adjusting the opening degree of the expansion valve 18 based on the temperature difference thus selected, the controller 70 may adjust the opening degree of the expansion valve 18 as shown in the flowchart of FIG.

  In the refrigerant cycle apparatus 100, it is possible to easily generate the flash gas at the start of the cooling operation when the operation state is not stable. Therefore, the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1 until a predetermined time elapses from the start of operation of the refrigerant cycle device 100 (step S101 to step S103 in the flowchart of FIG. 6). reference). Further, the controller 70 adjusts the opening degree of the expansion valve 18 based on the second temperature difference D2 after a predetermined time has elapsed from the start of operation of the refrigerant cycle device 100 and the flash gas becomes relatively difficult to be generated. (See step S103 to step S104 in the flowchart of FIG. 6). That is, in the flowchart of FIG. 6, the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1 at the timing when flash gas is likely to be generated, and based on the second temperature difference D2 at other timings. Thus, the opening degree of the expansion valve 18 is adjusted. The predetermined time may be appropriately determined to a value that makes it relatively difficult for the flash gas to be generated if the time elapses from the start of operation.

  Further, the controller 70 may execute the combination of the opening degree control of the expansion valve 18 in the flowchart of FIG. 6 and the opening degree control of the expansion valve 18 of the above embodiment. Specifically, the controller 70 adjusts the opening degree of the expansion valve 18 based on the first temperature difference D1 until a predetermined time elapses from the start of the operation of the refrigerant cycle device 100. Further, after a predetermined time has elapsed, the controller 70 selects one of the first temperature difference D1 and the second temperature difference D2 based on the first temperature T1 and the second temperature T2, and expands based on the selected temperature difference. Adjust the opening degree of the valve 18.

(6-3) Modification C
In the above embodiment, the refrigerant cycle device 100 is configured to be able to inject the gas refrigerant into the compression chamber in the middle of compression of the compression mechanism of the compressor 12, but the refrigerant cycle device may not be configured to be injectable. .

  In addition, when injecting a gas refrigerant into the compression chamber in the middle of compression of the compression mechanism of the compressor 12 with a structure like the said embodiment, flash gas is generate | occur | produced with the heat source side heat exchanger 20 which functions as a condenser. Also, even when the injection valve 36 is opened, the refrigerant is not sufficiently supplied to the compressor 12 through the injection flow passage 35, and the capacity of the refrigerant cycle device 100 is not sufficiently ensured.

(6-4) Modification D
In the above-described embodiment, the heat source side heat exchanger 20 combines the main heat exchange unit 22, the sub heat exchange unit 28, and the refrigerant flowing through the main heat exchange unit 22 into one and leads the diverter 25 to the sub heat exchange unit 28. Including. However, the heat source side heat exchanger may not have the secondary heat exchange unit 28.

  For example, the refrigerant cycle device 100 may have a single heat exchange portion 122 and may include the pressure loss portion 125. The pressure loss portion 125 is, for example, a reduction portion of the flow passage area of the heat transfer tube of the heat exchange portion 122 (for example, a portion where the refrigerant flow passage area is reduced to 80% or less as compared with the upstream side). Further, for example, the pressure loss portion 125 is a merging portion (for example, a header pipe) of the refrigerant flow path in the flow direction of the refrigerant, in which the refrigerant flowing through the heat transfer pipe of the heat exchange portion 122 merges.

  The first temperature sensor 92c measures the temperature of the refrigerant flowing through the condenser as the first temperature T1 at the upstream side of the pressure loss portion 125 of the condenser (here, the heat source side heat exchanger 120) in the refrigerant flow direction A Do. The first temperature sensor 92c is preferably configured to set the temperature of the refrigerant flowing downstream of the center of the inlet 120a of the condenser and the outlet 120b of the condenser (the alternate long and short dash line M2 in FIG. 7) in the refrigerant flow path of the condenser. measure. The second temperature sensor 92d sets the refrigerant temperature downstream of the pressure loss portion 125 and upstream of the expansion valve 18 in the flow direction A of the refrigerant (for example, the refrigerant temperature flowing through the liquid refrigerant pipe 10d) as the second temperature T2. measure. Then, the controller 70 sets the temperature difference between the first temperature T1 and the condensation temperature Tc in the condenser as the first temperature difference D1, and sets the temperature difference between the second temperature T2 and the condensation temperature Tc as the second temperature difference D2. The opening degree of the expansion valve 18 is adjusted as in the above embodiment.

(6-5) Modification E
Although the case where the heat source side heat exchanger 20 functions as a condenser was demonstrated to the example in the said embodiment, it is not limited to this.

  For example, when the use side heat exchanger 62 has a pressure loss portion as described in the above embodiment, and the opening degree of the expansion valve 18 is adjusted based on the degree of supercooling, the refrigerant flow during heating operation The first temperature sensor measures the temperature of the refrigerant flowing through the use side heat exchanger 62 as the first temperature T1 upstream of the pressure loss portion of the use side heat exchanger 62 in the direction, and the refrigerant flow during heating operation A second temperature sensor for measuring the temperature of the refrigerant downstream of the pressure loss portion of the use side heat exchanger 62 and upstream of the expansion valve 18 in the second direction as the second temperature T2, and the method according to the above embodiment The opening degree of the expansion valve 18 may be adjusted in the same manner as in FIG.

(6-6) Modification F
In the said embodiment, although the refrigerant cycle apparatus 100 is an apparatus which can switch and perform cooling operation and heating operation, it is not limited to this. For example, the refrigerant cycle device 100 may be a device capable of performing only a cooling operation.

(6-7) Modification G
In the refrigerant cycle device 100 of the above embodiment, the pressure loss portion of the heat source side heat exchanger 20 functioning as a condenser is the flow divider 25, but the pressure loss portion is not limited to the flow divider.

  As described above, the pressure loss portion is a portion where the pressure drop can be larger when flowing the refrigerant into the condenser than in the upstream side. The pressure loss part other than the flow divider (for example, the branch part of the refrigerant flow channel, the bend of the refrigerant flow channel, the enlarged part of the refrigerant flow channel (including the rapid expansion part and the diffuser), the reduced part of the refrigerant flow channel The configuration of the above-described embodiment is also effective in the case of having a sharp reduction portion (including a nozzle).

  While the embodiments and modifications of the present disclosure have been described above, it is understood that various changes in form and detail can be made without departing from the spirit and scope of the present disclosure as set forth in the claims. Will.

  The present disclosure is widely applicable and useful to a refrigerant cycle device in which the opening degree of the expansion valve is adjusted according to the degree of subcooling.

12 compressor 18 expansion valve 20, 120 heat source side heat exchanger (condenser)
20a Gas side connection port (condenser inlet)
20b Liquid side connection port (condenser outlet)
22 Main Heat Exchanger (Heat Exchanger)
24 Small diameter pipe (piping)
24a 1st small diameter pipe (pipe connected at the lowest position to the heat exchange section)
25 shunt (pressure loss part, junction part, reduction part, connection part)
28 Secondary heat exchange part 62 Use side heat exchanger (evaporator)
70 Controller (Calculator, Controller)
80 Refrigerant circuit 92c 1st temperature center (1st thermometer side)
92d 2nd temperature center (2nd thermometer side)
Reference Signs List 100 refrigerant cycle device 120a inlet of condenser 120b outlet of condenser 125 pressure loss portion D1 first temperature difference D2 second temperature difference T1 first temperature T2 second temperature Tc condensation temperature

JP, 2013-137165, A

Claims (13)

A compressor (12) for compressing a refrigerant, a condenser (20, 120) for cooling and condensing the refrigerant compressed by the compressor, and an expansion valve (18) for reducing the pressure of the refrigerant condensed by the condenser A refrigerant circuit (80) comprising: a) an evaporator (62) for heating and evaporating the refrigerant flowing from the condenser through the expansion valve;
A first temperature measurement unit (92c) which measures the temperature of the refrigerant flowing through the condenser as a first temperature (T1) upstream of the pressure loss part (25, 125) of the condenser in the flow direction of the refrigerant )When,
A second temperature measurement unit (92d) configured to measure, as a second temperature (T2), the temperature of the refrigerant downstream of the pressure loss portion and upstream of the expansion valve in the flow direction of the refrigerant;
A temperature difference between the first temperature and the condensation temperature (Tc) in the condenser is a first temperature difference (D1), and a temperature difference between the second temperature and the condensation temperature is a second temperature difference (D2). A calculation unit (70) to calculate each
A control unit (70) configured to adjust the opening degree of the expansion valve based on the first temperature difference and the second temperature difference;
The refrigerant cycle device (100). The control unit selects one of the first temperature difference and the second temperature difference based on the first temperature and the second temperature, and adjusts the opening degree of the expansion valve based on the selected temperature difference. ,
The refrigerant cycle device according to claim 1. The control unit compares the first temperature difference with the second temperature difference, selects one of the first temperature difference and the second temperature difference based on the comparison result, and selects the first temperature difference based on the selected temperature difference. Adjust the opening degree of the expansion valve,
The refrigerant cycle device according to claim 2. The control unit selects the smaller one of the first temperature difference and the second temperature difference, and adjusts the opening degree of the expansion valve based on the selected temperature difference.
The refrigerant cycle device according to claim 3. The control unit is configured to set the expansion valve based on the first temperature difference until a predetermined time elapses from the start of operation of the refrigerant cycle device, and the second temperature difference after the predetermined time elapses from the start of the operation. Adjust the opening degree of
The refrigerant cycle device according to claim 1. The pressure loss portion is a merging portion of the refrigerant flow path in the flow direction of the refrigerant.
The refrigerant cycle device according to any one of claims 1 to 5. The pressure loss portion is a reduction portion of the refrigerant flow area.
The refrigerant cycle device according to any one of claims 1 to 6. The condenser (20) includes a main heat exchange section (22), a sub heat exchange section (28), and a connection section for joining the refrigerant flowing through the main heat exchange section and leading it to the sub heat exchange section ( 25) and,
The pressure loss portion is the connection portion.
The refrigerant cycle device according to any one of claims 1 to 5. The first temperature measurement unit is a temperature of the refrigerant flowing downstream of a center of the inlet (20a, 120a) of the condenser and the outlet (20b, 120b) of the condenser in the refrigerant flow path of the condenser To measure
The refrigerant cycle device according to any one of claims 1 to 8. The condenser (20) includes a plurality of pipes (24 for connecting the heat exchange section (22) disposed upstream of the junction section in the flow direction of the refrigerant, the heat exchange section and the junction section). And, and,
The first temperature measurement unit measures the temperature of the refrigerant flowing downstream from the center of the heat exchange unit in the flow direction of the refrigerant.
The refrigerant cycle device according to claim 6. The first temperature measurement unit measures the temperature of the refrigerant flowing through one of the pipes.
The refrigerant cycle device according to claim 10. The first temperature measurement unit measures the temperature of the refrigerant flowing downstream of the center of the heat exchange unit and the merging unit in the pipe in the flow direction of the refrigerant.
The refrigerant cycle device according to claim 11. The plurality of pipes are connected to the heat exchange section at different heights,
The first temperature measurement unit measures the temperature of the refrigerant flowing through the pipe (24a) connected to the heat exchange unit at the lowest position.
The refrigerant cycle device according to any one of claims 10 to 12.

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