Refrigeration cycle device

Abstract

To provide a refrigeration cycle device switching between a flow passage via an expansion valve and a flow passage not via the expansion valve in a simple structure not using an actuator so as to enhance an injection effect by both a heating operation and a cooling operation, with respect to each of the expansion valves mounted on both sides of an economizer.SOLUTION: A refrigeration cycle device includes: a first flow passage switch circuit which is provided between an economizer and a use-side heat exchanger, becomes into a state of making refrigerant flow via a first expansion valve when being in a circulation state corresponding to cooling, and becomes into a state of making the refrigerant flow while bypassing the first expansion valve when being in a circulation state corresponding to heating; and a second flow passage switch circuit which is provided between a heat-source-side heat exchanger and the economizer, makes the refrigerant flow via the second expansion valve when being in a circulation state corresponding to heating, and becomes into a state making the refrigerant flow while bypassing the second expansion valve when being in a circulation state corresponding to cooling.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a refrigeration cycle device. [Background technology]

[0002] Patent Document 1 discloses an air conditioner that enables the injection of refrigerant into the compressor during both heating and cooling operations by providing expansion valves on both sides of an economizer connected midway through the refrigerant circuit and the injection circuit. This air conditioner is configured to open the injection valve provided in the injection circuit to perform injection when it is determined that liquid refrigerant is stored in the intermediate receiver located between the two expansion valves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7017096 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a refrigeration cycle device that can enhance the injection effect in both heating and cooling operations by switching between a flow path that passes through the expansion valve and a flow path that does not pass through the expansion valve using a simple configuration that does not use an actuator for each expansion valve provided on both sides of an economizer. [Means for solving the problem]

[0005] The refrigeration cycle device of the present disclosure includes a compressor having an injection port communicating with a compression chamber, a utilization side heat exchanger, an economizer, and a heat source side heat exchanger, which are connected in sequence by refrigerant piping, and includes a main refrigerant circuit through which a refrigerant flows, a circulation state provided between the compressor and the utilization side heat exchanger and the heat source side heat exchanger, in which the refrigerant is discharged from the compressor to the utilization side heat exchanger, thereby circulating the refrigerant in the main refrigerant circuit in the direction from the compressor to the utilization side heat exchanger, and a circulation state in which the refrigerant is discharged from the compressor to the heat source side heat exchanger. a four-way valve for switching between a cooling-compatible circulation state in which the refrigerant is circulated in a direction from the compressor to the heat source-side heat exchanger in the main refrigerant circuit, a first flow path provided in the main refrigerant circuit between the economizer and the utilization-side heat exchanger for circulating the refrigerant in the main refrigerant circuit via the first expansion valve, and a second flow path for circulating the refrigerant in the main refrigerant circuit without passing through the first expansion valve, and when in the cooling-compatible circulation state, the flow of refrigerant through the second flow path is blocked by a refrigerant pressure whose application direction is switched according to the flow direction of the refrigerant in the main refrigerant circuit, a first flow path switching circuit that, in a heating circulation state, blocks the flow of refrigerant through the first flow path and circulates the refrigerant through the second flow path; a third flow path that is provided in a main refrigerant circuit between the economizer and the heat source side heat exchanger and causes the refrigerant to flow through the main refrigerant circuit via the second expansion valve; and a fourth flow path that causes the refrigerant to flow through the main refrigerant circuit without passing through the second expansion valve. The cooling circulation state is controlled by a refrigerant pressure whose application direction is switched according to the flow direction of the refrigerant in the main refrigerant circuit. a second flow path switching circuit that, when in a heating-compatible circulation state, blocks the flow of refrigerant through the third flow path and allows the refrigerant to flow through the fourth flow path, and when in a heating-compatible circulation state, blocks the flow of refrigerant through the fourth flow path and allows the refrigerant to flow through the third flow path; a bypass refrigerant circuit that branches off from the refrigerant piping between the first flow path switching circuit and the second flow path switching circuit and communicates with the injection port of the compressor via the third expansion valve; and a controller that controls the operation of the four-way valve to switch between a cooling-compatible circulation state and a heating-compatible circulation state. Effect of the Invention

[0006] The refrigeration cycle device of the present disclosure can enhance the injection effect in both heating and cooling operations by switching between a flow path that passes through the expansion valve and a flow path that does not pass through the expansion valve, using a simple configuration that does not use an actuator for each expansion valve provided on both sides of the economizer. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a configuration of a refrigeration cycle device according to an embodiment during heating operation. [Diagram 2] FIG. 1 is a block diagram showing a state during cooling operation of a refrigeration cycle device according to an embodiment of the present invention; [Diagram 3] Control block diagram of a refrigeration cycle device according to an embodiment [Figure 4] FIG. 1 is a pressure-enthalpy diagram (Ph diagram) during cooling operation of a refrigeration cycle device according to an embodiment of the present invention. [Diagram 5] 1 is a flowchart showing a control process at the start of heating operation and cooling operation of a refrigeration cycle device according to an embodiment of the present invention; [Figure 6] FIG. 2 is another configuration diagram of the flow path switching circuit of the refrigeration cycle device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (The knowledge and other information that formed the basis of this disclosure)

[0009] At the time when the inventors came up with the present disclosure, there was a technology that enabled injection operation during both heating operation and cooling operation in a refrigeration cycle device by providing expansion valves in both the refrigerant piping between the economizer and the user-side heat exchanger and the refrigerant piping between the economizer and the heat source-side heat exchanger. However, when expansion valves are provided on both sides of the economizer, the refrigerant is decompressed by the expansion valve and then branches into the main refrigerant circuit and the bypass refrigerant circuit for injection during both cooling and heating operations. Then, in the economizer, heat exchange occurs between the refrigerant flowing through the main refrigerant circuit and the refrigerant further decompressed by the expansion valve in the bypass circuit. Therefore, the inventors have discovered a problem that the temperature difference between the refrigerant in the main refrigerant circuit and the refrigerant in the bypass circuit that exchanges heat in the economizer becomes smaller than when decompression by the expansion valve is not performed upstream of the economizer, reducing the amount of heat exchange in the economizer and making the energy saving effect of the injection operation insufficient.

[0010] As a means for solving the above problem, it is conceivable to provide an actuator such as a three-way valve that switches between a flow path for circulating the refrigerant via the expansion valve and a flow path for circulating the refrigerant bypassing the expansion valve for each expansion valve provided on both sides of the economizer, and to control the expansion valve upstream of the economizer to be bypassed depending on whether the operation is cooling or heating. However, the inventors have found a problem that in this case, it is necessary to perform complex control to control the operation of the actuator to bypass the expansion valve. Furthermore, the inventors have found a problem that when a highly flammable refrigerant such as R290 refrigerant is filled, it is necessary to have a molded configuration so that the contact part of the actuator is not exposed in case of refrigerant leakage from the refrigerant circuit, which makes the actuator's component configuration complicated. In order to solve the above problems, the inventors have come up with the subject matter of the present disclosure. The present disclosure provides a refrigeration cycle device that can increase the effect of injection in both heating and cooling operations by switching a flow path that passes through the expansion valve and a flow path that does not pass through the expansion valve with a simple configuration that does not use an actuator for each expansion valve provided on both sides of an economizer.

[0011] Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming more redundant than necessary and to facilitate understanding by those skilled in the art. It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0012] (Embodiment) Hereinafter, the embodiment will be described with reference to FIGS. 1 to 6. FIG. [1. Configuration] 1 and 2 are configuration diagrams of a refrigeration cycle device 1 according to this embodiment. The refrigeration cycle device 1 is a vapor compression type refrigeration cycle device, and includes a main refrigerant circuit 10, a bypass refrigerant circuit 20, and a controller 100. The refrigeration cycle device 1 is capable of heating operation and cooling operation, and Fig. 1 shows the flow direction of the refrigerant during heating operation with arrows, while Fig. 2 shows the flow direction of the refrigerant during cooling operation with arrows.

[0013] The main refrigerant circuit 10 is configured by connecting in order a compressor 11 that compresses a refrigerant, a utilization side heat exchanger 12 that functions as a condenser (during heating operation) or an evaporator (during cooling operation), an economizer 13, and a heat source side heat exchanger 14 that functions as a condenser (during cooling operation) or an evaporator (during heating operation) by refrigerant piping 16. A first flow path switching circuit 50 is provided in the main refrigerant circuit 10 between the utilization side heat exchanger 12 and the economizer 13, and a second flow path switching circuit 60 is provided in the main refrigerant circuit 10 between the heat source side heat exchanger 14 and the economizer 13.

[0014] A four-way valve 15 is provided in the main refrigerant circuit 10 between the compressor 11 and the utilization-side heat exchanger 12 and the heat-source-side heat exchanger 14. The four-way valve 15 switches the direction in which the refrigerant discharged from the compressor 11 flows through the main refrigerant circuit 10. That is, the four-way valve 15 switches the direction in which the refrigerant discharged from the compressor 11 flows through the main refrigerant circuit 10 between a heating-compatible circulation state indicated by an arrow in Fig. 1 and a cooling-compatible circulation state indicated by an arrow in Fig. 2.

[0015] 1, in the heating-compatible circulation state, in the main refrigerant circuit 10, the refrigerant flows in the order of the compressor 11 → four-way valve 15 → utilization-side heat exchanger 12 → first flow path switching circuit 50 → economizer 13 → second flow path switching circuit 60 → heat source-side heat exchanger 14 → four-way valve 15 → compressor 11. Also, in the cooling-compatible circulation state, as shown in Fig. 2, in the main refrigerant circuit 10, the refrigerant flows in the order of the compressor 11 → four-way valve 15 → heat source-side heat exchanger 14 → second flow path switching circuit 60 → economizer 13 → first flow path switching circuit 50 → utilization-side heat exchanger 12 → four-way valve 15 → compressor 11.

[0016] The first flow path switching circuit 50 is configured by connecting a first flow path 51 and a second flow path 55 in parallel between a first connection port 50a on the side of the utilization side heat exchanger 12 and a second connection port 50b on the side of the economizer 13. In the first flow path 51, a first check valve 52, a second check valve 53, and a first expansion valve 54 are connected in series with the first check valve 52 and the second check valve 53 being forward from the second connection port 50b to the first connection port 50a. In the second flow path 55, a third check valve 56 and a fourth check valve 57 are connected in series with the forward direction being from the first connection port 50a to the second connection port 50b. Furthermore, a first communication passage 58 communicates between the first check valve 52 and the second check valve 53 in the first flow path 51 and between the third check valve 56 and the fourth check valve 57 in the second flow path 55.

[0017] The first check valve 52, the second check valve 53, the third check valve 56, and the fourth check valve 57 have valve bodies that are closed by the pressure (back pressure) of the refrigerant in the reverse direction to prevent the flow of the refrigerant. In the heating circulation state, the first check valve 52 and the second check valve 53 are closed, so that the flow of the refrigerant through the first expansion valve 54 via the first flow path 51 is prevented, and the third check valve 56 and the fourth check valve 57 are maintained in an open state, so that the refrigerant flows through the second flow path 55, bypassing the first expansion valve 54. On the other hand, in the cooling circulation state, the third check valve 56 and the fourth check valve 57 are closed, so that the flow of the refrigerant through the second flow path 55 is prevented, and the first check valve 52 and the second check valve 53 are maintained in an open state, so that the refrigerant flows through the first flow path 51 via the first expansion valve 54.

[0018] The second flow path switching circuit 60 is configured by connecting a third flow path 61 and a fourth flow path 65 in parallel between a third connection port 60a on the heat source side heat exchanger 14 side and a fourth connection port 50b on the economizer 13 side. In the third flow path 61, a fifth check valve 62, a sixth check valve 63, and a second expansion valve 64 are connected in series with the fifth check valve 62 and the sixth check valve 63 being forward from the fourth connection port 60b to the third connection port 60a. In the fourth flow path 65, a seventh check valve 66 and an eighth check valve 67 are connected in series with the forward direction being from the third connection port 60a to the fourth connection port 60b. Furthermore, a second communication passage 68 communicates between a portion between the fifth check valve 62 and the sixth check valve 63 in the third flow path 61 and a portion between the seventh check valve 66 and the eighth check valve 67 in the fourth flow path 65.

[0019] The fifth check valve 62, the sixth check valve 63, the seventh check valve 66, and the eighth check valve 67 also have valve bodies that are closed by the pressure (back pressure) of the refrigerant in the reverse direction to prevent the flow of the refrigerant. In the heating circulation state, the seventh check valve 66 and the eighth check valve 67 are closed, so that the flow of the refrigerant through the fourth flow path 65 is prevented, and the fifth check valve 62 and the sixth check valve 63 are maintained in an open state, so that the refrigerant flows through the third flow path 61 via the second expansion valve 64. On the other hand, in the cooling circulation state, the fifth check valve 62 and the sixth check valve 63 are closed, so that the flow of the refrigerant through the third flow path 61 via the second expansion valve 64 is prevented, and the seventh check valve 66 and the eighth check valve 67 are maintained in an open state, so that the refrigerant flows through the fourth flow path 65, bypassing the second expansion valve 64.

[0020] The bypass refrigerant circuit 20 branches off from the refrigerant pipe 16 between the economizer 13 and the first flow path switching circuit 50, and communicates with an injection port 11a provided in a compression chamber of the compressor 11. A third expansion valve 21 and the economizer 13 are connected to the bypass refrigerant circuit 20 in this order from the upstream side. The third expansion valve 21 is an opening degree adjustment valve whose opening degree can be changed.

[0021] During heating operation, a portion of the high-pressure refrigerant that has passed through the utilization-side heat exchanger 12 flows into the bypass refrigerant circuit 20, and during cooling operation, a portion of the high-pressure refrigerant that has passed through the heat-source-side heat exchanger 14 flows into the bypass refrigerant circuit 20. The refrigerant that has flowed into the bypass refrigerant circuit 20 is reduced in pressure by the third expansion valve 21 to become an intermediate-pressure refrigerant, and the intermediate-pressure refrigerant exchanges heat with the high-pressure refrigerant flowing through the main refrigerant circuit 10 in the economizer 13, and is then injected into the compressor 11. The refrigerant injected into the compressor 11 merges with the refrigerant that is being compressed in the compression chamber of the compressor 11. The compressor 11 merges the injected refrigerant with the refrigerant that is being compressed, and recompresses it.

[0022] The heat medium circuit 30 is configured by connecting the utilization side heat exchanger 12, the conveying pump 31, and the air conditioning terminal 33 with the heat medium pipe 32. Water or antifreeze can be used as the heat medium circulating through the heat medium circuit 30. In the utilization side heat exchanger 12, heat exchange is performed between the refrigerant flowing through the main refrigerant circuit 10 and the heat medium flowing through the heat medium circuit 30. During heating operation, the heat medium flowing through the heat medium circuit 30 is heated by the utilization side heat exchanger 12, and the air conditioning terminal 33 functions as a heating terminal, and during cooling operation, the heat medium flowing through the heat medium circuit 30 is cooled by the utilization side heat exchanger 12, and the air conditioning terminal 33 functions as a cooling terminal.

[0023] The refrigerant piping 16 on the discharge side of the compressor 11 is provided with a discharge pressure sensor 41 that detects the pressure of the refrigerant discharged from the compressor 11. The refrigerant piping 16 on the suction side of the compressor 11 is provided with a suction pressure sensor 42 that detects the pressure of the refrigerant sucked into the compressor 11. The heat medium piping 32 on the inlet side of the use-side heat exchanger 12 is provided with a pre-heating temperature sensor 43 that detects the temperature of the heat medium near the inlet of the use-side heat exchanger 12. An outside air temperature sensor 44 that detects the outside air temperature is provided near the heat source-side heat exchanger 14.

[0024] The refrigeration cycle apparatus 1 includes a controller 100 that controls the operation of the compressor 11, the four-way valve 15, the third expansion valve 21, the conveying pump 31, etc. to perform cooling operation and heating operation, and a remote control 110 for starting and stopping the heating operation and cooling operation, setting the operating conditions, etc. Fig. 3 is a control block diagram of the refrigeration cycle apparatus 1. Referring to Fig. 3, the controller 100 is connected to a discharge pressure sensor 41, a suction pressure sensor 42, a pre-heating temperature sensor 43, and an outside air temperature sensor 44, and detection signals from these sensors are input to the controller 100.

[0025] The controller 100 is also connected to the compressor 11, the four-way valve 15, the third expansion valve 21, and the conveying pump 31, and the operation of these actuators is controlled by a control signal output from the controller 100. The controller 100 is also connected to a remote control 110. The remote control 110 has a switch and a display unit, and an operation signal of the switch is input to the controller 100, and the operating state of the refrigeration cycle apparatus 1 is displayed on the display unit of the remote control 110 in response to a display signal output from the controller 100.

[0026] The controller 100 includes a processor 101 and a memory 102, which stores a program 103 for controlling the refrigeration cycle apparatus 1 and control data 104 for determining control conditions for the compressor 11 and the third expansion valve 21 in heating operation and cooling operation. The processor 101 controls the operation of the refrigeration cycle apparatus 1 by reading and executing the program 103.

[0027] The operation of the refrigeration cycle device 1 in cooling operation will be described with reference to Fig. 2 and Fig. 4. Fig. 4 is a pressure-enthalpy diagram (Ph diagram) in the case where refrigerant is injected into the compressor 11. Points (a) to (h) in Fig. 4 correspond to the locations (a) to (h) in Fig. 2, respectively.

[0028] First, the high-pressure refrigerant (a) discharged from the compressor 11 dissipates heat in the heat source side heat exchanger 14, and then flows through the main refrigerant circuit 10 via the fourth flow path 65 of the second flow path switching circuit 60 and the economizer 13, and at (c) a part of the high-pressure refrigerant branches off to the bypass refrigerant circuit 20. The high-pressure refrigerant that has flowed into the bypass refrigerant circuit 20 is reduced in pressure to an intermediate pressure by the third expansion valve 21 to become intermediate-pressure refrigerant (g), and the intermediate-pressure refrigerant exchanges heat with the high-pressure refrigerant flowing through the main refrigerant circuit 10 in the economizer 13.

[0029] In this way, in the main refrigerant circuit 10, the high-pressure refrigerant that has released heat in the heat source-side heat exchanger 14 and been cooled in the economizer 13 to reduce its enthalpy flows through the first flow path 51 of the first flow path switching circuit 50 and is depressurized by the first expansion valve 54 (b). The refrigerant (b) depressurized by the first expansion valve 54 decreases in the refrigerant dryness (weight ratio of gas-phase components to the total refrigerant) in the user-side heat exchanger 12, and the liquid component of the refrigerant increases, evaporates in the user-side heat exchanger 12, and returns to the suction side (f) of the compressor 11. Meanwhile, the intermediate-pressure refrigerant (g) depressurized to an intermediate pressure by the third expansion valve 21 of the bypass refrigerant circuit 20 is heated by the high-pressure refrigerant flowing through the main refrigerant circuit 10 in the economizer 13, and merges with the refrigerant being compressed in the compressor 11 from the injection port 11a of the compressor 11 at (h) in a state in which its enthalpy has increased.

[0030] During heating operation, as shown in FIG. 1, the flow direction of the refrigerant in the main refrigerant circuit 10 is reversed from that during cooling operation. In the first flow path switching circuit 50, the refrigerant flows through the second flow path 55 without being reduced in pressure, and in the second flow path switching circuit 60, the refrigerant flows through the third flow path 61 after being reduced in pressure by the second expansion valve 64.

[0031] 2, during cooling operation, the flow path of the second flow path switching circuit 60 is switched to the fourth flow path 65, and thus the high-pressure refrigerant flowing through the main refrigerant circuit 10 is prevented from being depressurized by the second expansion valve 64 of the third flow path 61. Therefore, the temperature of the high-pressure refrigerant decreases due to the depressurization, and the temperature difference between the refrigerant on the main refrigerant circuit 10 side and the refrigerant on the bypass refrigerant circuit 20 side in the economizer 13 becomes smaller, and it is possible to suppress a decrease in the amount of heat exchange by the economizer 13. Similarly, during heating operation, it is possible to suppress a decrease in the amount of heat exchange by the economizer 13 by preventing the high-pressure refrigerant from being depressurized by the first expansion valve 54 upstream of the economizer 13.

[0032] [2. Control processing] The control process executed by the controller 100 when an operation to start the heating operation or the cooling operation is performed by the remote control 110 will be described with reference to the flowchart shown in FIG.

[0033] 5, the controller 100 determines in step S1 whether or not an operation to start heating operation has been performed via the remote control 110, and determines in step S10 whether or not an operation to start cooling operation has been performed via the remote control 110. When the controller 100 recognizes an operation to start heating operation via the remote control 110, the controller 100 advances the process from step S1 to step S2, and when the controller 100 recognizes an operation to start cooling operation via the remote control 110, the controller 100 advances the process from step S10 to step S11.

[0034] Steps S2 and S3 are processes corresponding to the heating operation. In step S2, the controller 100 controls the four-way valve 15 to a heating-compatible circulation state in which the refrigerant discharged from the compressor 11 flows in the direction from the compressor 11 to the utilization-side heat exchanger 12, as shown in Fig. 1. This causes the utilization-side heat exchanger 12 to function as a condenser, and the heat-source-side heat exchanger 14 to function as an evaporator, as shown in Fig. 1.

[0035] In the next step S3, the controller 100 starts the compressor 11 to start the heating operation. Based on a control map for the heating operation stored in the control data 104, the controller 100 controls the operation frequency of the compressor 11, the opening degree of the third expansion valve 21, and the operation frequency of the conveying pump 31 in accordance with detection signals from the discharge pressure sensor 41, the suction pressure sensor 42, the pre-heating temperature sensor 43, and the outside air temperature sensor 44, and the heating temperature set by the remote control 110, etc.

[0036] Steps S11 and S12 are processes corresponding to the cooling operation. In step S11, the controller 100 controls the four-way valve 15 to a cooling-compatible circulation state in which the refrigerant discharged from the compressor 11 flows in the direction from the compressor 11 to the heat source-side heat exchanger 14, as shown in Fig. 2. This causes the heat source-side heat exchanger 14 to function as a condenser, and the utilization-side heat exchanger 12 to function as an evaporator, as shown in Fig. 2.

[0037] In the next step S12, the controller 100 starts the compressor 11 to start the cooling operation. Based on a control map for cooling operation stored in the control data 104, the controller 100 controls the operation frequency of the compressor 11, the opening degree of the third expansion valve 21, and the operation frequency of the conveying pump 31 in accordance with detection signals from the discharge pressure sensor 41, the suction pressure sensor 42, the pre-heating temperature sensor 43, and the outside air temperature sensor 44, and the heating temperature set by the remote control 110, etc.

[0038] 4, the four-way valve 15 is simply controlled to switch between a heating-compatible circulation state and a cooling-compatible circulation state, and the flow paths of the refrigerant in the first flow path switching circuit 50 and the second flow path switching circuit 60 are switched by the pressure of the refrigerant, the application direction of which is switched depending on the flow direction of the refrigerant in the main refrigerant circuit 10. Therefore, without providing an actuator such as a three-way valve for bypassing the first expansion valve 54 (during heating operation) or the second expansion valve 64 (during cooling operation) on the upstream side of the economizer 13, it is possible to suppress a decrease in the heat exchange amount in the economizer 13 due to a reduction in the pressure of the refrigerant upstream of the economizer 13.

[0039] In addition, in a configuration in which an actuator such as a three-way valve is used to bypass the expansion valve, when a highly flammable refrigerant such as R290 refrigerant is sealed in the main refrigerant circuit 10 and the bypass refrigerant circuit 20, a molded configuration is required to prevent the contact parts of the actuator from being exposed in case of refrigerant leakage from the main refrigerant circuit 10 or the bypass refrigerant circuit 20; however, this makes such measures unnecessary.

[0040] [3. Effects, etc.] As described above, in the present embodiment, the refrigeration cycle device 1 includes the four-way valve 15 that switches the flow direction of the refrigerant in the main refrigerant circuit 10 between a heating-compatible circulation state and a cooling-compatible circulation state, the first flow path switching circuit 50 that, depending on the direction of the refrigerant flow pressure, causes the refrigerant to flow by bypassing the first expansion valve 54 that is upstream of the economizer 13 in the heating circulation state and causes the refrigerant to flow via the first expansion valve 54 that is downstream of the economizer 13 in the cooling circulation state, the second flow path switching circuit 60 that, depending on the direction of the refrigerant flow pressure, causes the refrigerant to flow by bypassing the second expansion valve 64 that is upstream of the economizer 13 in the cooling circulation state and causes the refrigerant to flow via the second expansion valve 64 that is downstream of the economizer 13 in the heating circulation state, the bypass refrigerant circuit 20, and the controller 100. The controller 100 controls the operation of the four-way valve 15 to switch between the heating-compatible circulation state and the cooling-compatible circulation state. In the refrigeration cycle device 1, the first expansion valve 54 and the second expansion valve 64, which are provided on both sides of the economizer 13, can be configured in a simple manner without using an actuator to switch between a flow path passing through the first expansion valve 54 and a flow path bypassing the first expansion valve 54, and also to switch between a flow path passing through the second expansion valve 64 and a flow path bypassing the second expansion valve 64, thereby enhancing the injection effect in both heating and cooling operations.

[0041] (Other embodiments) As described above, the above embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made.

[0042] In the above embodiment, the first flow path switching circuit 50 and the second flow path switching circuit 60 are configured as a bridge circuit using four check valves as shown in Figures 1 and 2, but the flow paths may be switched according to the direction of the refrigerant flow pressure by other configurations. For example, as shown in Figure 6, a flow path switching circuit 200 can be used in which two check valves 211 and 221 are connected in parallel with the forward direction reversed.

[0043] The flow path switching circuit 200 is configured by connecting in parallel a flow path 210 between a first connection port 200a and a second connection port 200b, in which a check valve 211 and an expansion valve 212 are connected in series with the forward direction of the check valve 211 being from the first connection port 200a to the second connection port 200b, and a flow path 220 in which a check valve 221 is connected with the forward direction being from the second connection port 200b to the first connection port 200a.

[0044] In the flow path switching circuit 200, when the refrigerant flows from the first connection port 200a to the second connection port 200b as shown in S1, the flow of the refrigerant to the flow path 220 side is blocked by the check valve 221, and the refrigerant flows through the flow path 210 via the expansion valve 212. Also, when the refrigerant flows from the second connection port 200b to the first connection port 200a as shown in S2, the flow of the refrigerant to the flow path 210 side is blocked by the check valve 211, and the refrigerant flows through the flow path 220, bypassing the expansion valve 212. Also, the first flow path switching circuit or the second flow path switching circuit of the present disclosure may be configured using a pressure responsive valve or the like of a type other than a check valve.

[0045] In the above embodiment, the first expansion valve 54 and the second expansion valve 64 are always open, but an on-off valve that can be switched between open and closed may be used as the first expansion valve 54 and the second expansion valve 64. In this case, as shown in Figs. 1 and 2, the controller 100 controls the opening and closing of the first expansion valve 54 and the second expansion valve 64. During the heating operation shown in Fig. 1, by controlling the first expansion valve 54 to a closed state (fully closed state), even if there is a risk that the first check valve 52 and the second check valve 53 may not be able to sufficiently block the flow of the refrigerant due to a low flow pressure of the refrigerant, it is possible to reliably prevent the refrigerant from flowing through the first expansion valve 54 and reducing the pressure of the refrigerant. Furthermore, during cooling operation as shown in Figure 2, by controlling the second expansion valve 64 to a closed state (fully closed state), even if the refrigerant flow pressure is low and the fifth check valve 62 and the sixth check valve 63 may not be able to sufficiently block the flow of the refrigerant, it is possible to reliably prevent the refrigerant from flowing through the second expansion valve 64 and reducing the pressure of the refrigerant.

[0046] The controller in the present disclosure may be any controller capable of controlling the device in the present disclosure. When expressing the subject matter of the invention, the device in the present disclosure may be controlled by a control means, a control unit, or similar terms in addition to the controller. The controller can be realized in various forms. For example, a processor may be used as the controller. If a processor is used as the controller, various processes can be executed by loading a program from a storage medium storing the program into the processor and executing the program by the processor. Therefore, the process contents can be changed by changing the program stored in the storage medium, so that the degree of freedom in changing the control contents can be increased. Examples of the processor include a CPU (Central Processing Unit) and an MPU (Micro-Processing Unit). Examples of the storage medium include a hard disk, a flash memory, and an optical disk. In addition, a wired logic in which the program cannot be rewritten may be used as the controller. Using a wired logic as the controller is effective in improving the processing speed. Examples of the wired logic include an ASIC (Application Specific Integrated Circuit). In addition, the controller may be realized by combining a processor and a wired logic. If the controller is realized by combining a processor and wired logic, it is possible to increase the degree of freedom of software design and improve the processing speed. In addition, the controller and a circuit having a function different from that of the controller may be configured with a single semiconductor element. An example of a circuit having a different function is an A / D-D / A conversion circuit. In addition, the controller may be configured with a single semiconductor element or multiple semiconductor elements. When configured with multiple semiconductor elements, each control described in the claims may be realized with different semiconductor elements. Furthermore, the controller may be configured with a configuration including a semiconductor element and a passive component such as a resistor or a capacitor.

[0047] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0048] The present disclosure is applicable to a refrigeration cycle device that injects refrigerant into a compressor, in which each expansion valve provided on both sides of an economizer can be switched between a flow path that passes through the expansion valve and a flow path that does not pass through the expansion valve using a simple configuration that does not use an actuator, thereby enhancing the injection effect in both heating and cooling operations. [Explanation of symbols]

[0049] 1 Refrigeration cycle equipment 10 Main refrigerant circuit 11 Compressor 12 User side heat exchanger 13 Economizer 14 Heat source side thermal response ventilation 15 Four-way valve 16 Refrigerant piping 20 Bypass refrigerant circuit 21 Third expansion valve 30 Heat carrier circuit 31 Transfer pump 32 Heat medium piping 33 Air Conditioning Terminal 41 Discharge pressure sensor 42 Intake pressure sensor 43 Pre-heating temperature sensor 44 Outside Air Temperature Sensor 50 First flow path switching circuit 51 First Channel 52 First check valve 53 Second check valve 54 First expansion valve 55 Second Flow Path 56 Third check valve 57 Fourth check valve 58 1st communication passage 60 Second flow path switching circuit 61 Third Stream 62 5th check valve 63 6th check valve 64 Second expansion valve 65 4th Stream 66 7th check valve 67 No. 8 check valve 68 2nd communication passage 100 Controller 101 Processor 102 Memory 103 Programs 104 Control Data 110 Remote Control

Claims

1. a main refrigerant circuit in which a refrigerant flows, the main refrigerant circuit including a compressor having an injection port communicating with a compression chamber, a utilization side heat exchanger, an economizer, and a heat source side heat exchanger, which are connected in sequence by a refrigerant pipe; a four-way valve provided between the compressor and the utilization side heat exchanger and the heat source side heat exchanger, for switching between a heating-compatible circulation state in which a refrigerant is circulated in the main refrigerant circuit in a direction from the compressor to the utilization side heat exchanger by discharging a refrigerant from the compressor to the utilization side heat exchanger, and a cooling-compatible circulation state in which a refrigerant is circulated in the main refrigerant circuit in a direction from the compressor to the heat source side heat exchanger by discharging a refrigerant from the compressor to the heat source side heat exchanger; a first flow path switching circuit that is provided in the main refrigerant circuit between the economizer and the utilization side heat exchanger, the first flow path switching circuit having a first flow path that circulates a refrigerant through the main refrigerant circuit via a first expansion valve and a second flow path that circulates the refrigerant through the main refrigerant circuit without passing through the first expansion valve, and that, depending on a refrigerant pressure whose application direction is switched according to a flow direction of the refrigerant in the main refrigerant circuit, blocks the flow of the refrigerant through the second flow path and allows the refrigerant to flow through the first flow path in the cooling corresponding circulation state, and blocks the flow of the refrigerant through the first flow path and allows the refrigerant to circulate through the second flow path in the heating corresponding circulation state; a second flow path switching circuit that is provided in the main refrigerant circuit between the economizer and the heat source side heat exchanger, the second flow path switching circuit having a third flow path that circulates a refrigerant through the main refrigerant circuit via a second expansion valve and a fourth flow path that circulates a refrigerant through the main refrigerant circuit without passing through the second expansion valve, and that, depending on a refrigerant pressure whose application direction is switched according to a flow direction of the refrigerant in the main refrigerant circuit, blocks the flow of refrigerant through the third flow path and allows the refrigerant to flow through the fourth flow path in the cooling corresponding circulation state, and blocks the flow of refrigerant through the fourth flow path and allows the refrigerant to flow through the third flow path in the heating corresponding circulation state; a bypass refrigerant circuit branching off from the refrigerant piping between the first flow path switching circuit and the second flow path switching circuit and communicating with an injection port of the compressor via a third expansion valve; A controller that controls the operation of the four-way valve to switch between the cooling circulation state and the heating circulation state; A refrigeration cycle device comprising:

2. The first flow path switching circuit and the second flow path switching circuit are configured using a check valve that prevents the flow of refrigerant in the reverse direction by a valve body that closes due to back pressure. The refrigeration cycle device according to claim 1.

3. the first flow path switching circuit is connected to the refrigerant piping by a first connection port on the utilization side heat exchanger side and a second connection port on the economizer side, the first flow path and the second flow path communicate with each other between the first connection port and the second connection port, the first flow path is configured by connecting a first check valve and a second check valve in series with the first expansion valve with a forward direction being from the second connection port to the first connection port, the second flow path is configured by connecting a third check valve and a fourth check valve in series with a forward direction being from the first connection port to the second connection port, and a location between the first check valve and the second check valve in the first flow path is communicated with a location between the third check valve and the fourth check valve in the second flow path, The second flow path switching circuit is connected to the refrigerant piping by a third connection port on the heat source side heat exchanger side and a fourth connection port on the economizer side, and the third flow path and the fourth flow path communicate with the third connection port and the fourth connection port, the third flow path is configured by connecting a fifth check valve and a sixth check valve in series with the second expansion valve with a forward direction being from the fourth connection port to the third connection port, and the fourth flow path is configured by connecting a seventh check valve and an eighth check valve in series with a forward direction being from the third connection port to the fourth connection port, and a portion of the third flow path between the fifth check valve and the sixth check valve communicates with a portion of the fourth flow path between the seventh check valve and the eighth check valve. The refrigeration cycle device according to claim 2.

4. The refrigerant is a highly flammable refrigerant. The refrigeration cycle device according to any one of claims 1 to 3.

5. the first expansion valve and the second expansion valve are open / close valves that can be switched between an open state and a closed state, The controller closes the second expansion valve when the four-way valve is used to establish the cooling circulation state, and closes the first expansion valve when the four-way valve is used to establish the heating circulation state. The refrigeration cycle device according to any one of claims 1 to 3.

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