JP2018179383A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle device capable of improving refrigeration cycle efficiency in both cases requiring different optimal injection amounts depending on with or without supercooling operation of an economizer by changing control methods of flow rate adjustment means.SOLUTION: In the refrigeration cycle device, an injection passage is branched from a main coolant circuit which connects a condenser and an expander. The injection passage has: a main passage branched from the main coolant circuit; a first passage which is connected to an injection port without passing through an economizer; a second passage which is connected to the injection port through the economizer; flow rate adjustment means which adjusts a flow rate of a coolant branched from the main coolant circuit; and second opening and closing means which opens and closes the second passage. The flow rate adjustment means adjusts the flow rate of the coolant in accordance with: a fluid outlet temperature of the economizer when the second opening and closing means is opened; and a discharge gas temperature of a compressor when the second opening and closing means is closed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a refrigeration cycle apparatus used for a refrigerator-freezer and the like.

In a refrigeration cycle apparatus used for a refrigerator or the like, it is necessary to further remove heat from a low temperature room or the like near a refrigeration temperature or a refrigeration temperature, and therefore, compared with the cooling of a general air conditioner, the liquid refrigerant in the indoor evaporator It is necessary to further reduce the evaporation temperature. In order to significantly lower the evaporation temperature of the liquid refrigerant, it is necessary to install an expansion valve on the upstream side of the evaporator and to greatly reduce the pressure of the liquid refrigerant flowing into the evaporator. If the pressure difference between the gas refrigerant on the suction side and the discharge side of the outdoor compressor increases due to the pressure reduction at the expansion valve, the temperature of the gas refrigerant in the compression process may increase to a high temperature of 100 ° C. or more. If the upper limit temperature Td _max of the above is exceeded, it may lead to the failure of the compressor.

Therefore, conventionally, by flowing the refrigerant after heat radiation with low specific enthalpy into the injection port provided in the middle of the compression process of the compressor, injection is performed to reduce the discharge temperature Td of the compressor to less than the upper limit temperature Td _max. ing.

  In addition, an economizer is known as a configuration for further improving the refrigeration efficiency of the entire refrigeration cycle apparatus. This branches a part of the liquid refrigerant that has passed through the outdoor condenser, decompresses the branched liquid refrigerant to lower the evaporation temperature, and exchanges the heat of the liquid refrigerant having a low evaporation temperature with the liquid refrigerant in the main refrigerant circuit. The liquid refrigerant in the main refrigerant circuit is cooled by evaporation. By adding such an economizer, the degree of subcooling of the liquid refrigerant supplied to the evaporation unit in the room can be increased, so that even when using an evaporator with the same evaporation capacity, the amount of refrigerant circulation can be reduced while cooling The subject can be cooled sufficiently. Then, if the circulation amount of the refrigerant decreases, the pressure loss in the piping section decreases, and the driving force of the compressor also decreases, so that the power consumption of the entire refrigeration cycle apparatus can be suppressed.

  DESCRIPTION OF RELATED ART There exists some which were described in patent document 1 as a refrigerating-cycle apparatus provided with the injection port demonstrated above and the economizer. The injection path of the document is composed of a main path branched from the main refrigerant circuit and first and second injection paths branched from the main path. Of the two injection paths, the refrigerant passing through the first injection path is supplied to the injection port without passing through the economizer, and the refrigerant passing through the second injection path passes through the economizer, that is, the main refrigerant circuit Is further cooled before being supplied to the injection port. In addition, the main path is provided with an electronic expansion valve (flow rate adjusting means) for adjusting the flow rate of refrigerant in the injection path, and in the first and second injection paths, two solenoid valves switching the opening and closing of the path independently. (Opening and closing means) is provided.

  With such a configuration, as shown in paragraphs 0038 to 0047 and the like of Patent Document 1, the cost is not increased by switching the injection path by two solenoid valves and adjusting the injection flow rate by one electronic expansion valve. In addition, the temperature of both the liquid outlet temperature from the economizer and the discharge gas temperature from the compressor is properly controlled.

JP, 2016-156557, A

  As a method of improving the efficiency of the refrigeration cycle apparatus, a method of reducing the driving force of the compressor by reducing the amount of refrigerant supplied to the injection port and reducing the amount of refrigerant compressed by the compressor can be considered.

  As another method of improving the efficiency, the number of revolutions of the compressor is reduced by supercooling the liquid refrigerant supplied to the indoor evaporator to lower the liquid temperature and reducing the necessary refrigerant circulation amount of the refrigeration cycle. It is conceivable to reduce the driving force of

  However, according to Patent Document 1, the amount of refrigerant supplied to the injection port is not controlled according to the utilization status of the economizer, so when performing supercooling by the economizer, the discharge gas temperature of the compressor can be sufficiently lowered. In addition, since the liquid refrigerant obtained by condensing the discharge gas can not be sufficiently cooled, the required refrigerant circulation amount of the refrigeration cycle does not decrease, and the load on the compressor increases. As a result, the efficiency of the refrigeration cycle may deteriorate. On the other hand, when the supercooling by the economizer is not performed, the amount of refrigerant supplied to the injection port becomes excessive, and the driving power of the compressor may increase, which may deteriorate the efficiency of the refrigeration cycle.

  That is, when performing supercooling by the economizer, there is room to improve the efficiency of the refrigeration cycle by further lowering the liquid outlet temperature from the economizer, and when not performing supercooling by the economizer, reduce the injection amount. There is room to improve the efficiency of the refrigeration cycle.

  In order to solve the above problems, a refrigeration cycle apparatus according to the present invention includes an outdoor unit and an indoor unit, and the outdoor unit includes a compressor that compresses gas refrigerant supplied from the indoor unit, and the compressor A condenser for condensing the discharged gas refrigerant and an economizer for further increasing the degree of subcooling of the refrigerant flowing out of the condenser are provided, and the indoor unit is configured to decompress the refrigerant condensed by the condenser. An expansion valve and an evaporator for evaporating the refrigerant reduced in pressure by the expansion valve are provided, and the refrigerant is transferred to the injection port of the compressor from the main refrigerant circuit connecting the condenser and the expansion valve. The injection path to flow is branched, and the injection path branches from the main path branched from the main refrigerant circuit and the main path, and is connected to the injection port without passing through the economizer. First flow path, a second path which branches from the main path, and is connected to the injection port via the economizer, and a flow path of the refrigerant which is provided in the main path and which branches from the main refrigerant circuit The flow rate adjusting means for adjusting and the second opening and closing means for opening and closing the second path, the flow rate adjusting means according to the liquid outlet temperature of the economizer when the second opening and closing means is open The refrigeration cycle apparatus adjusts the flow rate of the refrigerant, and adjusts the flow rate of the refrigerant according to the discharge gas temperature of the compressor when the second opening and closing means is closed.

  According to the present invention, by controlling the flow rate of the refrigerant flowed to the injection path according to the utilization status of the economizer, the efficiency of the refrigeration cycle can be obtained regardless of whether or not the supercooling is performed by the economizer. It can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic of the refrigerating-cycle apparatus of Example 1. FIG. The first control flow of the flow control valve when the solenoid valve on the economizer side is open. Second control flow of the flow control valve when the solenoid valve on the economizer side is open. Control flow of the flow control valve when the solenoid valve on the economizer side is closed. FIG. 2 is a schematic view of a refrigeration cycle apparatus of a second embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the configurations of the following embodiments, and various modifications and applications may be included within the scope of the technical concept of the present invention.

The block diagram of FIG. 1 is a schematic of the refrigeration cycle apparatus 100 of the first embodiment. The refrigeration cycle apparatus 100 of the present embodiment is used for a refrigerator-freezer etc. and cools a refrigerator case, a refrigerator case, a freezer case, a freezer interior and the like installed indoors, and as shown here, it is generally used It consists of a refrigerator 100a installed outdoors, an evaporation unit 100b generally installed indoors, a liquid pipe 9 connecting them, a gas pipe 12 and the like.
<Overview of refrigeration cycle>
Hereinafter, the outline of the refrigeration cycle of the refrigeration cycle apparatus 100 will be described while following the flow of the refrigerant indicated by the arrow in FIG. 1.

  First, the gas refrigerant flowing out of the evaporator 11 of the evaporation unit 100b passes through the gas pipe 12 and flows into the accumulator 1 from the suction side inlet of the refrigerator 100a. The accumulator 1 separates the liquid refrigerant from the gas refrigerant when the refrigerant that has flowed in includes the liquid refrigerant, and suppresses the amount of the liquid refrigerant flowing into the compressor 2 to a predetermined amount or less. To prevent the failure of the The compressor 2 compresses low-pressure gas refrigerant into high-pressure gas refrigerant using the rotational driving force generated by a motor (not shown), and when using inverter control for motor control, its rotational speed is stable It takes a certain amount of time to do it.

  The gas refrigerant flowing out of the accumulator 1 flows to the suction port 2a of the compressor 2, passes through the compression process, and becomes a high pressure and high temperature gas refrigerant and flows out from the discharge port 2b. The high-pressure and high-temperature gas refrigerant flowing out of the discharge port 2 b radiates heat to the outside air in the condenser 3 and flows out as condensed liquid refrigerant. As the condenser 3 used here, for example, a form such as a finned-tube heat exchanger that allows outside air to flow by a fan to dissipate heat to the air, a plate heat exchanger that uses external water, or the like can be considered. The refrigerant flowing out of the condenser 3 is temporarily stored in the receiver tank 4. The receiver tank 4 adjusts the surplus of the liquid refrigerant in the entire refrigeration cycle, and the liquid refrigerant is accumulated in the condenser 3 by retaining the surplus liquid refrigerant in the inside of the receiver tank 4 so that the condensation of the gas refrigerant is performed. It is possible to avoid a situation in which the performance is degraded.

  The refrigerant flowing out of the receiver tank 4 is further cooled by the subcooler 5. Although the refrigerant flowing into the subcooler 5 has a substantially saturated temperature unless the receiver tank 4 is full, the degree of supercooling is obtained by further cooling the refrigerant at the saturated temperature by the subcooler 5.

  The main refrigerant circuit on the downstream side of the subcooler 5 is a flow path of liquid refrigerant passing through the economizer 6 and the liquid pipe 9 and reaching the expansion valve 10 in the evaporation unit 100b.

The liquid refrigerant that has flowed through the main refrigerant circuit is decompressed by the expansion valve 10, and flows into the evaporator 11 as a liquid refrigerant whose evaporation temperature has dropped. The liquid refrigerant that has flowed into the evaporator 11 cools the room when it absorbs heat from the room and evaporates, and becomes a gas refrigerant and flows out of the evaporator 11. The gas refrigerant is again supplied to the refrigerator 100 a through the gas pipe 12 to complete the refrigeration cycle in the refrigeration cycle apparatus 100 of the present embodiment.
<Injection route>
Here, the compressor 2 of the present embodiment has an injection port 2c, as in Patent Document 1. Generally, the injection port 2c is structured to be connected to the middle of the compression process of the compression chamber. In the refrigeration cycle apparatus 100, unlike in a general air conditioner, the pressure in the evaporator 11 is that of the air conditioner so that the room can be cooled to a desired refrigeration temperature or refrigeration temperature regardless of the outside air temperature. By keeping the temperature lower, it is necessary to lower the evaporation temperature of the liquid refrigerant. For this reason, in the compressor 2 of the present embodiment, it is necessary to increase the pressure increase rate compared to the air conditioner, and the difference between the suction pressure and the discharge pressure tends to be large. When the difference between the suction pressure and the discharge pressure is large, the temperature of the gas refrigerant tends to rise in the compression process, and depending on the conditions, for example, it may be considered to exceed 100 ° C.

In the compressor, generally, an upper limit temperature Td _max on the specifications of the discharge gas is determined, and if the upper limit temperature Td _max is exceeded, it may be considered that the compressor may fail. Therefore, even in the refrigeration cycle apparatus 100 of the present embodiment, the discharge temperature Td of the compressor 2 is lowered by injecting the refrigerant having a low specific enthalpy to the injection port 2c of the compressor 2, thereby avoiding failure of the compressor 2. I am trying to

  In order to introduce the refrigerant with low specific enthalpy after heat release into the injection port 2c, in this embodiment, the injection path from the main refrigerant circuit between the subcooler 5 and the economizer 6 to the injection port 2c of the compressor 2 is branched .

  This injection path is, as shown in FIG. 1, a main path branched from the main refrigerant circuit, and a first injection path 31 branched from the main path and directly passing to the injection port 2c without passing through the economizer 6; A second injection path 32 is branched from the main path and passes through the economizer 6 to the injection port 2c. Further, the main passage is provided with a flow control valve 7 for adjusting the flow rate of the refrigerant branched from the main refrigerant circuit, and each of the first injection passage 31 and the second injection passage 32 opens and closes each injection passage. The solenoid valves 8a and 8b are provided.

Among these, the solenoid valve 8 b provided in the second injection path 32 switches between use and non-use of the economizer 6. Here, the economizer 6 performs heat exchange by causing the refrigerant flowing in the main refrigerant circuit and the refrigerant whose evaporation temperature has been lowered by the pressure reduction at the flow control valve 7 to flow next to each other to lower the temperature of the refrigerant flowing in the main refrigerant circuit. It is a heat exchanger for the purpose of obtaining a degree of subcooling, and for example, a plate heat exchanger or a double pipe is used. By the action of such economizer 6, the liquid refrigerant with the degree of supercooling flows out to the liquid pipe 9 when the solenoid valve 8b is opened, and the degree of cooling changes when the solenoid valve 8b is closed. No liquid refrigerant flows out.
<Control circuit of refrigerant flow path and refrigerant flow>
The refrigerator 100a is provided with a control circuit 21 for controlling the flow rate adjusting valve 7 and the solenoid valves 8a and 8b in accordance with conditions such as the outside air temperature, and the compressor 2 to measure the temperature of each place. A discharge gas temperature sensor 22 for measuring the discharge gas temperature Td, an outside air temperature sensor 23 for measuring the outside air temperature, and a liquid outlet temperature sensor 24 for measuring the liquid outlet temperature flowing out from the economizer 6 are provided. The control circuit 21 can control the flow control valve 7 and the solenoid valves 8a and 8b based on the information from these temperature sensors.
<Control flow of flow control valve when using economizer>
The control circuit 21 opens the solenoid valve 8b of the second injection path 32 and operates the refrigeration cycle while performing supercooling by the economizer 6 as follows.

  The first situation is that the liquid pipe 9 is installed in an environment where there is no problem even if condensation occurs, or the liquid pipe 9 is sufficiently insulated so that control for suppressing condensation is not necessary. To actively lower the liquid outlet temperature as much as possible and to improve the efficiency of the refrigeration cycle as much as possible.

  The control flow of the flow rate adjustment valve in this case will be described with reference to FIG. First, the solenoid valve 8a is closed and the solenoid valve 8b is opened, so that all the refrigerant in the injection path flows through the second injection path 32, and then the operation of the refrigeration cycle is started (S21). In addition, although the example which closes the solenoid valve 8a is shown here, you may perform the following control in the state which open | released this depending on the condition.

Next, the control circuit 21 controls the opening degree of the flow rate adjustment valve 7 so that the discharge gas temperature Td measured by the discharge gas temperature sensor 22 is a temperature range lower than a predetermined temperature range (upper limit temperature Td _{max in the} specification) It temporarily fixes with the opening degree which became) (S22).

  Thereafter, after the rotation speed of the compressor 2 is stabilized and the amount of refrigerant flowing in the injection path settles for a predetermined time (S23), the liquid outlet temperature is measured (S24). When the liquid outlet temperature is higher than the lower limit temperature (the lower limit temperature on the specification which can not be cooled further), the opening degree of the flow control valve 7 is increased to increase the low pressure refrigerant amount supplied to the second injection path 32 ( S25). Thereby, the heat exchange in the economizer 6 can be promoted, and the liquid outlet temperature can be brought close to the lower limit temperature. On the other hand, when the liquid outlet temperature is lowered to the lower limit temperature, it can be judged that the low-pressure refrigerant of an appropriate amount is supplied to the second injection path 32, so the opening degree of the flow control valve 7 at that time is maintained To do (S26).

  According to the control of FIG. 2 described above, the discharge gas temperature is suppressed to prevent the failure of the compressor, and the liquid refrigerant flowing out to the liquid pipe 9 is actively supercooled by the economizer 6 to thereby exit the liquid outlet. The load on the compressor 2 can be reduced and the efficiency of the refrigeration cycle can be improved by lowering the temperature to the lower limit temperature and minimizing the required refrigerant circulation amount of the refrigeration cycle.

  The second situation in which the refrigeration cycle is operated while performing supercooling by the economizer 6 is to make the liquid outlet temperature higher than the outside air temperature to suppress condensation on the liquid pipe 9, or the temperature difference between the liquid outlet temperature and the outside air temperature It is a case where it is desired to control the liquid outlet temperature so as to satisfy any of the above, and to improve the efficiency of the refrigeration cycle while suppressing the occurrence of condensation.

  The control flow of the flow rate adjustment valve in this case will be described with reference to FIG. First, after the solenoid valves 8a and 8b are both opened, the operation of the refrigeration cycle is started (S31). In addition, in order to suppress the cooling performance of the economizer 6, although the example which opened the solenoid valve 8a is shown here, you may perform the following control in the state which closed this depending on the condition.

Next, the control circuit 21 adjusts the opening degree of the flow rate adjustment valve 7, and the discharge gas temperature Td measured by the discharge gas temperature sensor 22 is a temperature range lower than a predetermined temperature range (upper limit temperature Td _{max in the} specification) It temporarily fixes with the opening degree which became) (S32).

  Thereafter, after the rotation speed of the compressor 2 is stabilized and the amount of refrigerant flowing in the injection path settles for a predetermined time (S33), the temperature difference between the liquid outlet temperature and the outside air temperature is compared with the liquid outlet temperature sensor 24 and the outside air temperature It measures using sensor 23 (S34). When the liquid outlet temperature is considerably higher than the outside air temperature, it can be determined that the liquid outlet temperature can be further lowered, so increase the opening degree of the flow control valve 7 or close the solenoid valve 8a, The amount of low pressure refrigerant supplied to the second injection path 32 is increased (S35). Thereby, the heat exchange in the economizer 6 can be promoted, and the liquid outlet temperature can be lowered to about the outside air temperature. When the temperature difference between the liquid outlet temperature and the outside air temperature is within the predetermined range, it can be determined that the low-pressure refrigerant of an appropriate amount is supplied to the second injection path 32, so the opening degree of the flow control valve 7 is maintained ( S36). When the liquid outlet temperature is considerably lower than the outside air temperature, it can be determined that dew condensation occurs, so the opening degree of the flow control valve 7 is reduced and the amount of low pressure refrigerant supplied to the second injection path 32 is reduced. (S37). Thereby, the heat exchange in the economizer 6 can be suppressed, and the liquid outlet temperature can be raised to about the outside air temperature.

  When the solenoid valve 8a is initially closed, at the time of S37, the solenoid valve 8a is opened, and the amount of low-pressure refrigerant supplied to the economizer 6 is decreased to increase the liquid outlet temperature. Also good.

According to the control of FIG. 3 described above, the amount of refrigerant to be injected can be optimized and the efficiency of the refrigeration cycle can be improved as much as possible within the range where adhesion of condensation to the liquid piping 9 can be suppressed.
<Control flow of flow control valve when economizer is not used>
On the other hand, in a situation where supercooling by the economizer 6 is unnecessary, such as when the operation load of the refrigeration cycle apparatus 100 is small, the control circuit 21 closes the solenoid valve 8b on the second injection path 32 side to make the flow rate of injection possible. If it is reduced as much as possible, the efficiency of the compressor 2 will increase, and as a result, the efficiency of the entire refrigeration cycle will also increase.

  The control flow of the flow rate adjustment valve in this case will be described with reference to FIG. First, the solenoid valve 8a is opened and 8b is closed, and then the operation of the refrigeration cycle is started (S41).

Next, the control circuit 21 reduces the opening degree of the flow rate adjusting valve 7 and temporarily fixes the opening degree when the discharge gas temperature Td measured by the discharge gas temperature sensor 22 becomes the upper limit temperature Td _max. (S42).

Thereafter, after the rotational speed of the compressor 2 is stabilized and the amount of refrigerant flowing in the injection path settles for a predetermined time (S43), the discharge gas temperature Td is measured (S44). When the discharge gas temperature Td was had increased from the upper limit temperature Td _max, since the compressor 2 can be determined and may be destroyed, and supplies the injection port 2c increases the opening degree of the flow rate control valve 7 The low pressure refrigerant amount is increased (S45). As a result, the discharge gas temperature Td can be lowered to less than the upper limit temperature Td _max , and failure of the compressor 2 can be avoided. When the discharge gas temperature Td is not changed from the upper limit temperature Td _max the appropriate amount of low-pressure refrigerant in the injection port 2c is it can be determined to have been supplied, to maintain the opening degree of the flow rate adjusting valve 7 (S46). When the discharge gas temperature Td has fallen from the upper limit temperature Td _max , it can be determined that there is room for reduction of the injection amount, so the opening degree of the flow rate adjustment valve 7 is reduced and the low pressure refrigerant amount supplied to the injection port 2c Reduce (S47). In this case, the discharge gas temperature Td rises to approximately the upper limit temperature Td _max, result injection amount decreases, the load of the compressor 2 is reduced, thereby improving the efficiency of the refrigeration cycle.

According to the control of FIG. 4 described above, the amount of injection is controlled so that the discharge gas temperature Td becomes a temperature near the upper limit temperature Td _max , so that the compressor 2 exceeds the upper limit temperature in the specification. While preventing the load, the load of the compressor 2 can be reduced, and the efficiency of the refrigeration cycle at low load can be improved as much as possible.

  As described above, in the refrigeration cycle apparatus 100 according to the present embodiment, the opening degree of the flow rate adjusting valve 7, ie, the control of the amount of refrigerant flowing in the injection path is controlled according to the open / close state of the solenoid valve 8b on the economizer 6 side. By switching the input signal to be used between the discharge gas temperature Td and the liquid outlet temperature, the load on the compressor 2 can be optimized regardless of the use condition of the economizer 6, and the refrigeration cycle apparatus can improve the efficiency of the refrigeration cycle. You can get it.

  The efficiency of the refrigeration cycle can be further enhanced by controlling the combination of the opening and closing of the solenoid valves 8a and 8b and the timing of the opening and closing switching in addition to the opening control of the flow rate adjusting valve 7 described above. it can.

  That is, when the solenoid valve 8b is closed during the operation of the refrigeration cycle, the solenoid valve 8a can be opened to perform injection into the compressor 2 at all times.

  When the solenoid valve 8a is closed and the solenoid valve 8b is open at the start of operation of the refrigeration cycle, the economizer 6 is turned on by opening the solenoid valve 8a when the liquid outlet temperature becomes considerably lower than the outside air temperature. It is possible to suppress the amount of refrigerant flowing to the second injection path 32 passing through and to increase the liquid outlet temperature.

  When both the solenoid valve 8a and the solenoid valve 8b are open at the start of the operation of the refrigeration cycle, the solenoid valve 8a is closed when the liquid outlet temperature becomes considerably higher than the outside air temperature. The amount of refrigerant flowing to the second injection path 32 can be increased to lower the liquid outlet temperature.

  At the start of operation of the refrigeration cycle, when the solenoid valve 8a is closed and the solenoid valve 8b is opened, the injection valve of the compressor 2 is opened by opening the solenoid valve 8a when the discharge gas temperature reaches a predetermined value or more. The amount of refrigerant directly supplied to the port 2c can be increased to lower the discharge gas temperature.

  When both the solenoid valve 8a and the solenoid valve 8b are open at the start of operation of the refrigeration cycle, closing the solenoid valve 8b causes the injection port 2c of the compressor 2 to be closed when the discharge gas temperature exceeds the predetermined value. The amount of refrigerant directly supplied can be increased to lower the discharge gas temperature.

  When the solenoid valve 8a is open and the solenoid valve 8b is closed at the start of operation of the refrigeration cycle, the solenoid valve 8b is opened when the discharge gas superheat degree of the compressor 2 becomes equal to or less than a predetermined value. By warming the refrigerant supplied to the injection port 2c of the compressor 2 via the solenoid valve 8b and warming the compressor 2, it is possible to increase the degree of superheat of the discharge gas.

  When both the solenoid valve 8a and the solenoid valve 8b are open at the start of operation of the refrigeration cycle, the solenoid valve 8a is closed when the discharge gas temperature of the compressor 2 becomes lower than a predetermined value. By reducing the amount of refrigerant directly supplied to the injection port 2c so that the temperature of the compressor 2 does not excessively decrease, the discharge gas temperature can be increased.

  Next, a refrigeration cycle apparatus 100 according to a second embodiment will be described with reference to FIG. The same points as in the first embodiment will not be repeatedly described.

  In the first embodiment, the injection path leading to the injection port 2c of the compressor 2 is branched from the main refrigerant circuit connecting the subcooler 5 and the economizer 6, but in the present embodiment, the main connecting the economizer 6 and the expansion valve 10 The injection path from the refrigerant circuit to the injection port 2c of the compressor 2 was branched.

  Since the refrigerant flowing out of the economizer 6 has a lower specific enthalpy than the refrigerant flowing out of the subcooler 5, if the refrigerant flowing out of the economizer 6 is used for injection as in this embodiment, only a smaller amount of refrigerant is injected. Then, since the same effect as that of the first embodiment can be obtained, the efficiency of the refrigeration cycle apparatus can be further enhanced than that of the first embodiment.

100 ... refrigeration cycle device,
100a ... refrigerator,
100b ... evaporation unit,
1 ... accumulator,
2 ... compressor,
2a ... inlet,
2b ... discharge port,
2c ... injection port,
3 ... Condenser,
4 ... Receiver tank,
5 ... Subcooler,
6 ... economizer,
7 ... Flow control valve,
8a, 8b ... solenoid valve,
9 ... Liquid piping,
10 ... expansion valve,
11 ... evaporator,
12 ... gas piping,
21 ... Control circuit,
22 ... Discharge gas temperature sensor,
23 ... outside temperature sensor,
24 ... Liquid outlet temperature sensor,
31 ... first injection path,
32 ... second injection path

Claims (13)

A refrigeration cycle apparatus including an outdoor unit and an indoor unit,
The outdoor unit further includes a compressor for compressing the gas refrigerant supplied from the indoor unit, a condenser for condensing the gas refrigerant discharged by the compressor, and a degree of supercooling of the refrigerant flowing out of the condenser. An economizer to increase the size of the
The indoor unit is provided with an expansion valve for decompressing the refrigerant condensed by the condenser, and an evaporator for evaporating the refrigerant decompressed by the expansion valve,
An injection path for flowing the refrigerant to the injection port of the compressor is branched from the main refrigerant circuit connecting the condenser and the expansion valve,
The injection path is
A main path branched from the main refrigerant circuit;
A first path branched from the main path and connected to the injection port without passing through the economizer;
A second path branched from the main path and connected to the injection port via the economizer;
Flow rate adjusting means provided in the main path for adjusting the flow rate of the refrigerant branched from the main refrigerant circuit;
Opening and closing means for opening and closing the second path;
The flow rate adjusting means is
If the opening / closing means is open, the flow rate of the refrigerant is adjusted according to the liquid outlet temperature of the economizer,
A refrigeration cycle apparatus, wherein the flow rate of the refrigerant is adjusted according to the discharge gas temperature of the compressor when the opening and closing means is closed. In the refrigeration cycle apparatus according to claim 1,
The flow rate adjusting means is
If the opening / closing means is open, the flow rate of the refrigerant is adjusted so that the liquid outlet temperature becomes the first target temperature,
The refrigeration cycle apparatus, wherein the flow rate of the refrigerant is adjusted so that the discharge gas temperature becomes the second target temperature when the opening and closing means is closed. In the refrigeration cycle apparatus according to claim 1,
The flow rate adjusting means, when the opening and closing means is open,
The temperature of the discharge gas falls within a temperature range lower than the upper limit of the specification, or
In order that the discharge gas superheat degree falls within a temperature zone higher than the specification upper limit temperature,
A refrigeration cycle apparatus characterized by adjusting a flow rate of a refrigerant. The refrigeration cycle apparatus according to any one of claims 1 to 3,
The refrigeration cycle apparatus, wherein the flow rate adjusting means adjusts the flow rate of the refrigerant such that the liquid outlet temperature becomes the lower limit temperature when the opening and closing means is open. In the refrigeration cycle apparatus according to claim 1 or 2,
The refrigeration cycle apparatus, wherein the flow rate adjusting means adjusts the flow rate adjusting means so that the difference between the outside air temperature and the liquid outlet temperature falls within a predetermined range when the opening and closing means is open. A refrigeration cycle apparatus including an outdoor unit and an indoor unit,
The outdoor unit further includes a compressor for compressing the gas refrigerant supplied from the indoor unit, a condenser for condensing the gas refrigerant discharged by the compressor, and a degree of supercooling of the refrigerant flowing out of the condenser. An economizer to increase the size of the
The indoor unit is provided with an expansion valve for decompressing the refrigerant condensed by the condenser, and an evaporator for evaporating the refrigerant decompressed by the expansion valve,
An injection path for flowing the refrigerant to the injection port of the compressor is branched from the main refrigerant circuit connecting the condenser and the expansion valve,
The injection path is
A main path branched from the main refrigerant circuit;
A first path branched from the main path and connected to the injection port without passing through the economizer;
A second path branched from the main path and connected to the injection port via the economizer;
Flow rate adjusting means provided in the main path for adjusting the flow rate of the refrigerant branched from the main refrigerant circuit;
First opening and closing means for opening and closing the first path;
And second opening and closing means for opening and closing the second path,
The flow rate adjusting means is
If the second opening / closing means is open, the flow rate of the refrigerant is adjusted according to the liquid outlet temperature of the economizer;
A refrigeration cycle apparatus characterized in that, when the second opening / closing means is closed, the flow rate of the refrigerant is adjusted in accordance with the discharge gas temperature of the compressor. In the refrigeration cycle apparatus according to claim 6,
When closing said 2nd opening-and-closing means, the said 1st opening-and-closing means is opened, The refrigeration cycle apparatus characterized by the above-mentioned. In the refrigeration cycle apparatus according to claim 6,
When the first opening and closing means is closed and the second opening and closing means is opened,
A refrigeration cycle apparatus characterized in that the first opening / closing means is opened when the difference between the outside air temperature and the liquid outlet temperature becomes equal to or less than a predetermined value. In the refrigeration cycle apparatus according to claim 6,
When the first opening / closing means and the second opening / closing means are both open,
A refrigeration cycle apparatus characterized in that the first opening / closing means is closed when the difference between the outside air temperature and the liquid outlet temperature becomes equal to or more than a predetermined value. In the refrigeration cycle apparatus according to claim 6,
When the first opening and closing means is closed and the second opening and closing means is opened,
A refrigeration cycle apparatus characterized in that the first opening / closing means is opened when the temperature of the discharge gas reaches a predetermined value or more. In the refrigeration cycle apparatus according to claim 6,
When the first opening / closing means and the second opening / closing means are both open,
A refrigeration cycle apparatus characterized in that the second opening / closing means is closed when the temperature of the discharge gas reaches a predetermined value or more. The refrigeration cycle apparatus according to claim 6, wherein the first opening and closing means is open and the second opening and closing means is closed.
A refrigeration cycle apparatus characterized in that the second opening / closing means is opened when the discharge gas superheat degree becomes equal to or less than a predetermined value. The refrigeration cycle apparatus according to claim 6, wherein the first opening / closing means and the second opening / closing means are both open,
A refrigeration cycle apparatus characterized in that the first opening / closing means is closed when the temperature of the discharge gas becomes lower than a predetermined value.

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