Refrigeration cycle equipment

Abstract

To provide a refrigeration cycle device that can store heat while suppressing a decrease in comfort. [Solution] The refrigeration cycle device 1 includes an indoor heat exchanger 10 that functions as a condenser indoors, a heat storage heat exchanger 6 that holds a heat storage material 61 used in a temperature range including the latent heat range which is a phase change temperature range, and heats the heat storage material 61 with the incoming refrigerant, first flow paths 12 and 32 connected to the indoor heat exchanger 10 that guide the refrigerant flowing into the indoor heat exchanger 10, a second flow path 33 that branches off from the first flow paths 12 and 32 and is connected to the heat storage heat exchanger 6 that guides the refrigerant flowing through the heat storage heat exchanger 6, a flow control valve 81 installed in the second flow path 33 that controls the flow rate of the refrigerant flowing through the heat storage heat exchanger 6, and a control unit 9 that controls the flow control valve 81 to adjust the flow rate of the refrigerant that heats the heat storage material 61 in accordance with the rise in temperature of the heat storage material 61, and to limit the flow rate of the refrigerant flowing into the heat storage heat exchanger 6 when the temperature of the heat storage material 61 is in the latent heat range.

Description

Technical Field

[0001] The present invention relates to a refrigeration cycle device.

Background Art

[0002] Conventionally, a refrigeration cycle device including a heat storage heat exchanger that exchanges heat between refrigerant discharged from a compressor and a heat storage material has been known. In this refrigeration cycle device, there is a conventional technique for switching between a heat storage heating operation and a defrosting heating operation for the purpose of melting frost generated in an outdoor heat exchanger while continuing the heating operation.

[0003] In this conventional technique, during the heat storage heating operation, the indoor heat exchanger and the heat storage heat exchanger are used as condensers, and the outdoor heat exchanger is used as an evaporator. Further, during the defrosting heating operation, the indoor heat exchanger and the outdoor heat exchanger are used as condensers, and the heat storage heat exchanger is used as an evaporator.

[0004] A conventional refrigeration cycle device includes a heat storage device that holds a heat storage material and heats the heat storage material according to the inflowing refrigerant, a pipe connected to the heat storage device that guides the inflow of the refrigerant, a flow rate adjustment valve installed in the pipe that controls the flow rate of the refrigerant, and a control unit connected to the flow rate adjustment valve that adjusts the flow rate of the refrigerant that heats the heat storage material according to the rise in temperature of the heat storage material.

[0005] The refrigeration cycle device described in Patent Document 1 performs a heat storage heating operation for heating a heat storage material during the heating operation. At this time, the temperature of the heat storage material rises according to the transfer of thermal energy. Further, the refrigeration cycle device described in Patent Document 1 performs a defrosting heating operation for melting frost generated in the outdoor heat exchanger while continuing the heating operation. At this time, the defrosting heating operation is performed using the heated heat storage material as a heat source.

[0006] The refrigeration cycle device includes an indoor heat exchanger where indoor air and refrigerant exchange heat. The refrigerant discharged from the compressor during the above-described heat storage heating operation is supplied to the indoor heat exchanger and the heat storage device, respectively. When the opening degree of the flow rate adjustment valve provided on the upstream side of the heat storage device is increased, the amount of refrigerant supplied to the indoor heat exchanger decreases. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2024-17845 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the aforementioned refrigeration cycle system, during thermal storage heating operation, the flow control valve located upstream of the thermal storage unit has its opening controlled based on the temperature of the thermal storage material. Specifically, a target temperature for the refrigerant flowing into the thermal storage heat exchanger is determined based on the temperature of the thermal storage material, and the flow control valve is opened to ensure that the temperature of the refrigerant flowing into the thermal storage heat exchanger approaches the target temperature.

[0009] Here, when using a latent heat storage material that can store a large amount of heat with a small amount of heat, conventional flow control valve opening control becomes inconvenient. The amount of refrigerant supplied to the heat storage heat exchanger is adjusted by controlling the opening of the flow control valve. The flow control valve is controlled so that its opening decreases as the difference between the temperature of the refrigerant flowing into the heat storage heat exchanger and the target temperature decreases. When using a sensible heat storage material, the temperature of the heat storage material rises in response to the transfer of thermal energy, so during heat storage heating operation, the difference between the temperature of the refrigerant flowing into the heat storage heat exchanger and the target temperature gradually decreases, and the amount of refrigerant flowing into the heat storage heat exchanger can be reduced. When the amount of refrigerant flowing into the heat storage heat exchanger decreases, the amount of refrigerant supplied to the indoor heat exchanger increases relatively. Therefore, the heating capacity increases. On the other hand, latent heat storage materials have a sensible heat region in which the temperature rises in response to the transfer of thermal energy, and a latent heat region in which the temperature does not rise even when thermal energy is applied. Therefore, when using latent heat storage materials, the difference between the temperature of the refrigerant flowing into the heat storage heat exchanger and the target temperature in the latent heat range does not decrease, making it impossible to reduce the amount of refrigerant flowing into the heat storage heat exchanger. In other words, compared to using sensible heat storage materials, when using latent heat storage materials, flow rate control based on the temperature of the storage material increases the amount of refrigerant supplied to the heat storage heat exchanger in the latent heat range. As a result, the amount of refrigerant supplied to the indoor heat exchanger decreases relatively, which may reduce heating capacity and lower comfort.

[0010] The present invention aims to provide a refrigeration cycle device that can store heat while suppressing a decrease in comfort. [Means for solving the problem]

[0011] A refrigeration cycle device according to one aspect of the present invention includes a compressor, an indoor heat exchanger that functions as a condenser, a heat storage heat exchanger that holds a heat storage material used in a temperature range including the latent heat range which is a phase change temperature range, and heats the heat storage material with the incoming refrigerant, a heat storage material temperature sensor that detects the temperature of the heat storage material, a first flow path connected to the indoor heat exchanger and guiding the refrigerant flowing into the indoor heat exchanger, a second flow path branching from the first flow path and connected to the heat storage heat exchanger and guiding the refrigerant flowing into the heat storage heat exchanger, a flow control valve installed in the second flow path and controlling the flow rate of the refrigerant flowing through the heat storage heat exchanger, and a control unit that controls the flow control valve to adjust the flow rate of the refrigerant in accordance with the rise in the detected value of the heat storage material temperature sensor, and to limit the adjustment of the flow rate of the refrigerant flowing into the heat storage heat exchanger when the detected value of the heat storage material temperature sensor is in the latent heat range.

[0012] When refrigerant flows into a heat storage heat exchanger, the heat storage material is heated, and heat is stored in the heat storage material. On the other hand, if the temperature of the heat storage material is in the latent heat range, the temperature of the heat storage material does not change. According to the present invention, when the temperature of the heat storage material is in the latent heat range, the amount of refrigerant flowing into the heat storage heat exchanger can be appropriately adjusted to limit the amount of refrigerant flowing in. As a result, a sufficient flow rate of refrigerant for indoor heating can be secured, thereby suppressing a decrease in heating capacity. [Effects of the Invention]

[0013] This allows for a reduction in the amount of refrigerant supplied to the indoor heat exchanger by limiting the flow rate of refrigerant into the heat storage heat exchanger when the temperature of the heat storage material is in the latent heat range, thereby suppressing a decrease in heating capacity. [Brief explanation of the drawing]

[0014] [Figure 1] This is a refrigerant circuit diagram of a refrigeration cycle device according to an embodiment of the present invention. [Figure 2] This is a block diagram showing the internal configuration of the control unit in a refrigeration cycle device according to an embodiment of the present invention. [Figure 3] This flowchart shows the operation of a refrigeration cycle device according to an embodiment of the present invention. [Figure 4]This is a flowchart showing the operation of a refrigeration cycle device according to an embodiment of the present invention. [Figure 5] This is a flowchart showing the operation of a refrigeration cycle device according to an embodiment of the present invention. [Figure 6] This is a flowchart showing the operation of a refrigeration cycle device according to an embodiment of the present invention. [Figure 7] This is a flowchart showing the operation of a refrigeration cycle device according to a second embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the refrigeration cycle device disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment. Also, the following examples can be appropriately combined within a range that does not cause contradictions.

Examples

[0016] (Refrigeration Cycle Device 1) The structure of the refrigeration cycle device 1 according to the first embodiment of the present invention will be described while referring to FIG. 1. FIG. 1 is a refrigerant circuit diagram of the refrigeration cycle device 1 according to the embodiment of the present invention. The refrigeration cycle device 1 includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 is installed outdoors, and the indoor unit 3 is installed indoors.

[0017] (Outdoor Unit 2, Indoor Unit 3) The outdoor unit 2 includes a compressor 4, an outdoor heat exchanger 5, a heat storage heat exchanger 6, two switching valves 71 and 72, three expansion valves 81, 82, and 83, and a control unit 9. The indoor unit 3 includes an indoor heat exchanger 1*. The refrigeration cycle device 1 includes a compressor flow path 31 that forms the discharge path 12 and the suction path 13 of the compressor 4, a condensation evaporation flow path 32 that connects the second switching valve 72 to the first switching valve 71, and a heat storage flow path 33 that branches from the condensation evaporation flow path 32 and reaches the second switching valve 72. A branch path 15 that branches from the discharge path 12 at a branch point 17 and is connected to the second switching valve 72 and a confluence path 18 that extends from the second switching valve 72 and merges into the suction path 13 are connected to the compressor flow path 31. *There seems to be a mistake in the original text where it says "The indoor unit 3 includes an indoor heat exchanger 1*" with an asterisk. It should probably be "The indoor unit 3 includes an indoor heat exchanger 10" as per the context.

[0018] (Compressor 4) The discharge port of the compressor 4 is connected to the port a of the first switching valve 71 via the discharge path 12. Further, the suction port of the compressor 4 is connected to the port c of the first switching valve 71 via the suction path 13. The compressor 4 compresses the refrigerant sucked from the suction port and discharges it from the discharge port.

[0019] (First switching valve 71, second switching valve 72) The first switching valve 71 has four ports a, b, c, and d. The indoor heat exchanger 10 is connected to the port b via the condensation evaporation flow path 32. The port d is connected to the first confluence point 16 of the branch path 15 via the bypass path 14. The first switching valve 71 switches the connection relationship of the ports by being controlled by a control unit 9 described later. The second switching valve 72 has four ports a, b, c, and d. The branch path 15 branched from the discharge path 12 at the branch point 17 is connected to the port a. The heat storage heat exchanger 6 is connected to the port b via the heat storage flow path 33. The confluence path 18 that merges into the suction path 13 at the confluence point 19 is connected to the port c. The outdoor heat exchanger 5 is connected to the port d via the condensation evaporation flow path 32. The second switching valve 72 switches the connection relationship of the ports by being controlled by a control unit 9 described later.

[0020] (Indoor heat exchanger 10, outdoor heat exchanger 5) The indoor heat exchanger 10 and the outdoor heat exchanger 5 are connected to the condensation evaporation flow path 32 in order from the first switching valve 71 toward the second switching valve 72. The indoor heat exchanger 10 exchanges heat between the indoor air and the refrigerant. The outdoor heat exchanger 5 exchanges heat between the outdoor air and the refrigerant. The heat storage flow path 33 is connected to the condensation evaporation flow path 32 at the third confluence point 20 set between the outdoor heat exchanger 5 and the indoor heat exchanger 10.

[0021] (Heat storage heat exchanger 6) A heat storage heat exchanger 6 is positioned in the heat storage channel 33. The heat storage heat exchanger 6 comprises a heat storage material 61, a container 62 filled with the heat storage material 61, and a channel through which the refrigerant flows. The heat storage heat exchanger 6 exchanges heat between the heat storage material 61 and the refrigerant. The heat storage material 61 is a latent heat storage material that undergoes a change of state during heat storage and heat release. Specifically, water, paraffin-based materials (normal paraffin, isoparaffin, etc.), hydrate-based materials (calcium chloride hexahydrate, sodium sulfate decahydrate, sodium acetate trihydrate, etc.), fatty acid-based materials (capric acid, lauric acid, etc.) are used. In the heat storage heat exchanger 6, the refrigerant and the heat storage material 61 are in thermal contact. When the temperature of the refrigerant flowing into the heat storage heat exchanger 6 is higher than the temperature of the heat storage material 61, the refrigerant heats the heat storage material 61.

[0022] (Expansion valve 8) The refrigeration cycle device 1 is equipped with a first expansion valve 81 (flow control valve) between the branching point 17 of the discharge path 12 in the branch path 15 and the first confluence point 16. The refrigeration cycle device 1 is also equipped with a second expansion valve 82 in the heat storage passage 33 connecting the heat storage heat exchanger 6 and the third confluence point 20. Furthermore, the refrigeration cycle device 1 is equipped with a third expansion valve 83 in the condensation evaporation passage 32 connecting the indoor heat exchanger 10 and the third confluence point 20. The first expansion valve 81, the second expansion valve 82, and the third expansion valve 83 reduce the pressure of the refrigerant passing through them.

[0023] When cooling operation is performed in the refrigeration cycle device 1, the first switching valve 71 connects port a to port d and port b to port c. The second switching valve 72 connects port a to port d and port b to port c. The refrigerant discharged from the compressor 4 flows into the outdoor heat exchanger 5 through the second switching valve 72. The refrigerant is depressurized in the third expansion valve 83. The depressurized refrigerant flows into the indoor heat exchanger 10. The refrigerant flows from the first switching valve 71 into the suction passage 13 and is drawn into the compressor 4. During cooling operation, the first expansion valve 81 is fully open and the second expansion valve 82 is fully closed.

[0024] When thermal storage heating operation is performed in the refrigeration cycle device 1, the first switching valve 71 connects port a to port b and port c to port d. The second switching valve 72 connects port a to port b and port c to port d. The refrigerant discharged from the compressor 4 flows into the indoor heat exchanger 10 from the first switching valve 71. The refrigerant is depressurized in the third expansion valve 83. The depressurized refrigerant flows into the outdoor heat exchanger 5. The refrigerant flows into the suction passage 13 from the second switching valve 72 and is drawn into the compressor 4. At the same time, the refrigerant flows into the thermal storage heat exchanger 6 from the second switching valve 72. The refrigerant flowing out of the thermal storage heat exchanger 6 is depressurized in the second expansion valve 82 and flows into the outdoor heat exchanger 5. The refrigerant flowing out of the outdoor heat exchanger 5 flows into the suction passage 13 from the second switching valve 72. During thermal storage heating operation, the opening degree of the first expansion valve 81 is adjusted by the control described later. Here, the discharge passage 12 and the condensation / evaporation passage 32 form the first passage according to the present invention. The branch passage 15 and the thermal storage passage 33 form the second passage according to the present invention.

[0025] When defrosting and heating operation is performed in the refrigeration cycle device 1, the first switching valve 71 connects port a to port b and port c to port d. The second switching valve 72 connects port a to port d and port b to port c. The refrigerant discharged from the compressor 4 flows into the indoor heat exchanger 10 through the first switching valve 71. The refrigerant is depressurized in the second expansion valve 82. The depressurized refrigerant flows into the thermal storage heat exchanger 6. The refrigerant discharged from the compressor 4 simultaneously flows into the outdoor heat exchanger 5 through the second switching valve 72. The refrigerant is depressurized in the second expansion valve 82. The depressurized refrigerant flows into the thermal storage heat exchanger 6. The refrigerant flows from the second switching valve 72 into the suction passage 13 and is drawn into the compressor 4. During defrosting and heating operation, both the first expansion valve 81 and the second expansion valve 82 are fully open.

[0026] (Control Unit 9) The control unit 9 is installed in the outdoor unit 2. The control unit 9 controls the rotational speed of the compressor 4. The control unit 9 controls the opening degrees of the first expansion valve 81, the second expansion valve 82, and the third expansion valve 83. The control unit 9 also switches the flow of refrigerant circulating in the refrigerant circuit by switching the first switching valve 71 and the second switching valve 72.

[0027] (Sensors) Furthermore, the refrigeration cycle device 1 includes a discharge temperature sensor 21, an indoor heat exchanger temperature sensor 22, an outdoor heat exchanger temperature sensor 23, a heat storage material temperature sensor 24, an outside temperature sensor 25, and a heat storage heat exchanger pressure sensor 26. The control unit 9 acquires various parameters from these sensors.

[0028] (Discharge temperature sensor 21) The discharge temperature sensor 21 is installed in the discharge passage 12. The discharge temperature sensor 21 detects the discharge temperature, which is the temperature of the refrigerant discharged from the compressor 4. A signal identifying the detected discharge temperature is supplied to the control unit 9. The discharge temperature is used to control the third expansion valve 83.

[0029] (Indoor heat exchanger temperature sensor 22) The indoor heat exchanger temperature sensor 22 is installed in the indoor heat exchanger 10. The indoor heat exchanger temperature sensor 22 acquires the temperature of the refrigerant passing through the indoor heat exchanger 10. A signal identifying the acquired temperature is supplied to the control unit 9. Hereinafter, the temperature detected by the indoor heat exchanger temperature sensor 22 during thermal storage heating operation and defrost heating operation will be referred to as the "condensation temperature". The condensation temperature is used to control the first expansion valve 81, which will be described later.

[0030] (Outdoor heat exchanger temperature sensor 23) The outdoor heat exchanger temperature sensor 23 is installed on the outdoor heat exchanger 5. The outdoor heat exchanger temperature sensor 23 acquires the temperature of the refrigerant passing through the outdoor heat exchanger 5. A signal identifying the acquired temperature is supplied to the control unit 9. Hereinafter, the temperature detected by the outdoor heat exchanger temperature sensor 23 during thermal storage heating operation will be referred to as the "evaporation temperature". The evaporation temperature is used to control the third expansion valve 83.

[0031] (Heat storage material temperature sensor 24) The heat storage material temperature sensor 24 is installed in the heat storage heat exchanger 6. The heat storage material temperature sensor 24 detects the temperature of the heat storage material 61 filled in the container 62. A signal identifying the detected heat storage material temperature is supplied to the control unit 9. The heat storage material temperature is used to control the opening degree of the first expansion valve 81, which will be described later.

[0032] (Outside temperature sensor 25) The outdoor temperature sensor 25 is installed on the outdoor unit 2. The outdoor temperature sensor 25 detects the outdoor temperature, which is the temperature of the outdoor air flowing into the outdoor heat exchanger 5. A signal identifying the detected outdoor temperature is supplied to the control unit 9. The outdoor temperature is used to control the first expansion valve 81, which will be described later.

[0033] (Heat storage heat exchanger pressure sensor 26) The thermal storage heat exchanger pressure sensor 26 is installed in the thermal storage heat exchanger 6 or in the flow path near it. The thermal storage heat exchanger pressure sensor 26 acquires the pressure of the refrigerant passing through the thermal storage heat exchanger 6. A signal identifying the acquired pressure is supplied to the control unit 9. Hereinafter, the pressure detected by the thermal storage heat exchanger pressure sensor 26 during thermal storage heating operation will be referred to as the "thermal storage condensation pressure," and the thermal storage condensation pressure will be used to control the first expansion valve 81, which will be described later.

[0034] (Control Unit 9) Next, the control contents of the control unit 9 will be described in detail. Figure 2 is a block diagram showing the internal configuration of the control unit 9 in a refrigeration cycle device 1 according to an embodiment of the present invention. The control unit 9 comprises a parameter detection unit 91, a setting unit 92, a storage unit 93, a determination unit 94, and an actuator control unit 95.

[0035] (Parameter detection unit 91, setting unit 92, storage unit 93, determination unit 94, actuator control unit 95) The parameter detection unit 91 acquires parameters detected by the various sensors described above. These parameters may be continuously transmitted to the parameter detection unit 91 or acquired as needed. The setting unit 92 sets target values ​​for various controls based on the parameters acquired by the parameter detection unit 91. More details will be described later. The storage unit 93 is composed of, for example, a semiconductor or a magnetic disk and stores the target values ​​set by the setting unit 92. The determination unit 94 compares the target values ​​stored in the storage unit 93 with the parameters acquired by the parameter detection unit 91 and makes various determinations. The actuator control unit 95 controls the compressor 4, the first expansion valve 81, the second expansion valve 82, the third expansion valve 83, the first switching valve 71, and the second switching valve 72 based on the determination results of the determination unit 94.

[0036] (Explanation of refrigerant flow) The refrigeration cycle device 1 according to an embodiment of the present invention can perform heating operation, heat storage heating operation which stores heat in the heat storage material 61 simultaneously with heating operation, defrosting heating operation which melts frost on the outdoor heat exchanger 5 simultaneously with heating operation, and cooling operation. The flow of refrigerant in the refrigerant circuit in each operating mode will be described below with reference to Figure 1. Note that the heating operation and cooling operation will be omitted.

[0037] (Refrigerant flow during thermal storage heating operation) When the refrigeration cycle device 1 performs a thermal storage heating operation, which involves storing heat in the thermal storage material 61 while performing heating, the control unit 9 switches the first switching valve 71 to connect port a to port b and port c to port d. The control unit 9 also switches the second switching valve 72 to connect port a to port b and port c to port d.

[0038] (Compressor 4 - Indoor heat exchanger - Outdoor heat exchanger) As a result, the high-pressure gaseous refrigerant discharged from the compressor 4 flows into the indoor heat exchanger 10 via the discharge passage 12, the first switching valve 71, and the condensation / evaporation passage 32. The high-pressure gaseous refrigerant passing through the indoor heat exchanger 10 condenses and liquefies by exchanging heat with the indoor air. In other words, the indoor heat exchanger 10 functions as a "condenser". The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 10 flows into the third expansion valve 83 in the liquid-side passage. The high-pressure liquid-phase refrigerant passing through the third expansion valve 83 is depressurized and becomes a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant flowing out of the third expansion valve 83 flows into the outdoor heat exchanger 5.

[0039] (Compressor 4 ~ Heat Storage Heat Exchanger ~ Outdoor Heat Exchanger) Furthermore, a portion of the refrigerant flowing through the discharge passage 12 flows into the thermal storage heat exchanger 6 via the branching point 17, branching passage 15, the first expansion valve 81, the second switching valve 72, and the thermal storage passage 33. The high-pressure gaseous refrigerant passing through the thermal storage heat exchanger 6 condenses and liquefies by exchanging heat with the thermal storage material 61. In other words, the thermal storage heat exchanger 6 functions as a "condenser". The high-pressure liquid-phase refrigerant flowing out of the thermal storage heat exchanger 6 flows into the second expansion valve 82 in the thermal storage passage 33. The high-pressure liquid-phase refrigerant passing through the second expansion valve 82 is depressurized to become a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant flowing out of the second expansion valve 82 merges with the low-pressure two-phase refrigerant flowing through the condensation evaporation passage 32 at the third confluence point 20 and flows into the outdoor heat exchanger 5. At this time, the opening degree of the second expansion valve 82 is adjusted to a predetermined fixed opening degree. Specifically, the opening of the third expansion valve 83 is set such that the amount of refrigerant flowing into the thermal storage heat exchanger 6 is less than the amount of refrigerant flowing into the indoor heat exchanger 10. At this time, the opening of the third expansion valve 83 is adjusted by target discharge temperature control, for example, so that the value detected by the discharge temperature sensor 21 becomes the target value. The target discharge temperature is calculated from the rotational speed of the compressor 4, the value detected by the indoor heat exchanger temperature sensor 22, the value detected by the outdoor heat exchanger temperature sensor 23, etc.

[0040] (Outdoor heat exchanger ~ Compressor 4) The low-pressure two-phase refrigerant passing through the outdoor heat exchanger 5 evaporates and vaporizes by exchanging heat with the outdoor air. In other words, the outdoor heat exchanger 5 functions as an "evaporator". The low-pressure gaseous refrigerant flowing out of the outdoor heat exchanger 5 is drawn into the compressor 4 via the condensation-evaporation passage 32, the second switching valve 72, the confluence passage 18, and the suction passage 13.

[0041] (Refrigerant flow during defrost heating operation) When the refrigeration cycle device 1 performs defrost-heating operation, which involves heating operation while defrosting, the control unit 9 switches the first switching valve 71 to connect port a to port b and port c to port d. The control unit 9 also switches the second switching valve 72 to connect port a to port d and port b to port c.

[0042] (Compressor 4 ~ Indoor heat exchanger ~ Second expansion valve 82) As a result, the high-pressure gaseous refrigerant discharged from the compressor 4 flows into the indoor heat exchanger 10 via the discharge passage 12, the first switching valve 71, and the condensation / evaporation passage 32. The high-pressure gaseous refrigerant passing through the indoor heat exchanger 10 condenses and liquefies by exchanging heat with the indoor air. In other words, the indoor heat exchanger 10 functions as a "condenser". The high-pressure liquid refrigerant flowing out of the indoor heat exchanger 10 flows into the heat storage passage 33 from the third confluence point 20 of the condensation / evaporation passage 32, and flows into the second expansion valve 82 in the heat storage passage 33. At this time, the opening degree of the second expansion valve 82 is adjusted by target discharge temperature control, for example, so that the detected value of the discharge temperature sensor 21 becomes the target value. The target discharge temperature is calculated from the rotational speed of the compressor 4, the detected value of the indoor heat exchanger temperature sensor 22, the detected value of the outdoor heat exchanger temperature sensor 23, etc. Also, at this time, the opening degree of the third expansion valve 83 is adjusted to be fully open.

[0043] (Compressor 4 ~ Outdoor heat exchanger ~ Second expansion valve 82) Furthermore, a portion of the refrigerant flowing through the discharge passage 12 flows into the outdoor heat exchanger 5 via the branching point 17, branching passage 15, the first expansion valve 81, the second switching valve 72, and the condensation / evaporation passage 32. The refrigerant passing through the outdoor heat exchanger 5 condenses and liquefies by exchanging heat with the frost adhering to the outdoor heat exchanger 5. In other words, the outdoor heat exchanger 5 functions as a "condenser." At this time, defrosting of the outdoor heat exchanger 5 is performed. The high-pressure liquid-phase refrigerant flowing out of the outdoor heat exchanger 5 flows into the heat storage passage 33 from the third confluence point 20 of the condensation / evaporation passage 32, and flows into the second expansion valve 82 in the heat storage passage 33. At this time, the opening degree of the first expansion valve 81 is adjusted to be fully open.

[0044] (Second expansion valve 82 ~ Compressor 4) The high-pressure liquid-phase refrigerant passing through the second expansion valve 82 is depressurized to become a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant flowing out of the second expansion valve 82 flows into the regenerative heat exchanger 6. The low-pressure two-phase refrigerant passing through the regenerative heat exchanger 6 evaporates and vaporizes by exchanging heat with the heat storage material 61. In other words, the regenerative heat exchanger 6 functions as an "evaporator". The low-pressure gaseous refrigerant flowing out of the regenerative heat exchanger 6 is drawn into the compressor 4 via the heat storage flow path 33, the second switching valve 72, the confluence flow path 18, and the suction passage 13.

[0045] (Explanation of basic operation) As described above, the refrigeration cycle device 1 in the embodiment of the present invention includes an indoor heat exchanger 10 and an outdoor heat exchanger 5, in addition to a thermal storage heat exchanger 6. When the refrigeration cycle device 1 performs thermal storage heating operation, the refrigerant discharged from the compressor 4 flows not only into the indoor heat exchanger 10 but also into the thermal storage heat exchanger 6 via the first expansion valve 81. At this time, the amount of refrigerant flowing into the thermal storage heat exchanger 6 is adjusted by controlling the opening degree of the first expansion valve 81. The heat stored in the thermal storage material 61 during thermal storage heating operation is used as a heat source during defrosting heating operation.

[0046] (flowchart) Figures 3 to 6 are flowcharts showing the operation of the refrigeration cycle device 1 according to the first embodiment of the present invention. The process shown in Figure 3 is executed when the control unit 9 receives an instruction to start the thermal storage heating operation and starts the thermal storage heating operation, and a predetermined time has elapsed from the start of the thermal storage heating operation (for example, the time until the start control of the compressor 4 is completed). During the thermal storage heating operation, the parameter detection unit 91 constantly acquires the thermal storage material temperature.

[0047] (Main flow) First, the control unit 9 moves to a subroutine (Figure 4) that determines whether the current heat storage material temperature falls within the sensible heat range or the latent heat range (ST1). The determination unit 94 determines whether or not information indicating that the current heat storage material temperature is within the latent heat range is stored in the memory unit 93 (ST2). If it is within the latent heat range (ST2-YES), the latent heat range control mode described in the subroutine (Figure 5) is executed (ST3). If it is not within the latent heat range (it is within the sensible heat range) (ST2-NO), the sensible heat range control mode is executed (ST4).

[0048] (Figure 4: Subroutine_Temperature range determination based on the temperature rise of the heat storage material (1)) In ST21 of Figure 4, the control unit 9 calculates the rate of increase in the heat storage material temperature per unit time. Specifically, the parameter detection unit 91 stores the heat storage material temperature acquired by the parameter detection unit 91 in the storage unit 93, linked to the detection time information, and the value obtained by subtracting the past (e.g., 60 seconds ago) heat storage material temperature stored in the storage unit 93 from the current heat storage material temperature acquired by the parameter detection unit 91 is taken as the rate of increase per unit time (the second slope described later). The determination unit 94 determines whether the rate of increase is below a threshold (e.g., 1°C) (ST22). If it is below the threshold (ST22-YES), the determination unit 94 causes the storage unit 93 to store information indicating that the current heat storage material temperature is in the "latent heat range". If it exceeds the threshold (ST22-NO), the determination unit 94 causes the storage unit 93 to store information indicating that the current heat storage material temperature is in the "sensible heat range".

[0049] (Figure 4: Subroutine_Other Embodiments) Alternatively, instead of the operation of ST22 described above, the melting point temperature range may be read from the memory unit 93, and instead of the operation of ST23, an operation to determine whether or not the heat storage material temperature falls within the melting point temperature range may be performed. In this case, if the heat storage material temperature falls within the melting point temperature range (ST22-YES), the determination unit 94 stores information in the memory unit 93 indicating that the current heat storage material temperature is in the "latent heat range". If the temperature does not fall within the melting point temperature range (ST22-NO), the determination unit 94 stores information in the memory unit 93 indicating that the current heat storage material temperature is in the "sensible heat range". The melting point temperature range is a value specific to the heat storage material, and for example, a range of ±2 degrees from the melting point is set. Since the temperature of the heat storage material 61 is not necessarily constant from the beginning to the end of melting even in the latent heat range, conditions are set to allow for some sensible heat changes.

[0050] (Figure 5: Subroutine_Latent Heat Range Control Mode (1)) In ST31 of Figure 5, the control unit 9 estimates the appropriate flow rate in the first expansion valve 81. As a method for estimating the appropriate flow rate, the parameter detection unit 91 first acquires the current rotational speed of the compressor 4. Based on the acquired rotational speed of the compressor 4, the control unit 9 can estimate the circulation rate (kg / s) of the entire refrigeration cycle, and the setting unit 92 sets the appropriate flow rate of refrigerant flowing to the heat storage heat exchanger 6 based on this circulation rate. The appropriate flow rate of refrigerant flowing to the heat storage heat exchanger 6 is the flow rate of refrigerant that can supply the heat storage material with enough heat to complete the change in state of the heat storage material within an appropriate time, and is a value determined in advance by tests, etc. After that, the control unit 9 reads the opening degree of the first expansion valve 81 corresponding to the appropriate flow rate from the storage unit 93 (ST32). The opening degree of the first expansion valve 81 corresponding to the appropriate flow rate is determined in advance by tests, etc., and the storage unit 93 has in advance stored a table in which the opening degree of the first expansion valve 81 corresponding to the appropriate flow rate is set. The actuator control unit 95 controls the opening degree of the first expansion valve 81 so that it matches the opening degree of the first expansion valve 81 read from the memory unit 93 (ST33).

[0051] (Sensible heat range control mode) In the sensible heat range control mode, the control unit 9 specifically performs the following controls. Based on the opening degree of the first expansion valve 81 at the start of the thermal storage heating operation, the opening degree of the first expansion valve 81 is adjusted as needed in accordance with the temporal change in the temperature of the thermal storage material 61, as described below, to adjust the amount of heat exchanged between the refrigerant and the thermal storage material in the thermal storage heat exchanger 6. Specifically, the opening degree of the first expansion valve 81 is determined in the flow shown in Figure 6. First, the parameter detection unit 91 acquires the thermal storage material temperature from the thermal storage material temperature sensor 24, the condensation temperature from the indoor heat exchanger temperature sensor 22, and the outside temperature from the outside temperature sensor 25. Based on these parameters, the setting unit 92 sets a first slope and stores it in the storage unit 93 (ST41). The first slope is set based on this temperature information so that, between consecutive defrosting operations, a value is set such that sufficient heat can be stored in the thermal storage heat exchanger 6 for use in the subsequent defrosting operation during the heating and thermal storage operation from the end of the previous defrosting operation until the start of the subsequent defrosting operation.

[0052] Next, the determination unit 94 calculates a second slope indicating the rate of temperature increase of the heat storage material 61 per unit time from the current heat storage material temperature and the most recent heat storage material temperature acquired by the parameter detection unit 91 (ST42). Then, the determination unit 94 compares this second slope with the first slope stored in the storage unit 93 (ST43).

[0053] If the determination unit 94 compares the second tilt with the first tilt and finds that the second tilt is greater than the first tilt (ST43-YES), the actuator control unit 95 controls the opening of the first expansion valve 81 to be smaller (ST44). This is because if the thermal storage heating operation is continued at this opening, there is a risk that an excess of heat will be stored in the thermal storage heat exchanger 6 for use in the subsequent defrosting operation, which will relatively reduce the amount of refrigerant supplied to the indoor heat exchanger 10 and decrease the heating capacity.

[0054] On the other hand, if the first slope is the same as or greater than the second slope (ST43-NO), the determination unit 94 then determines whether the second slope is equal to the first slope (ST45). Here, "equal to the second slope and the first slope" does not only mean that they are exactly equal, but may also include cases where, for example, a range in which they can be considered equal is set in advance, and the difference between the second slope and the first slope falls within that range.

[0055] If the determination unit 94 determines that the second inclination and the first inclination are equal (ST45-YES), the actuator control unit 95 controls the opening of the first expansion valve 81 to be maintained (ST46). This is because the heat storage heat exchanger 6 has stored enough heat to be used in the subsequent defrosting operation.

[0056] On the other hand, if the determination unit 94 determines that the second slope and the first slope are not equal (ST45-NO), this corresponds to the case where the second slope is smaller than the first slope. In other words, in this case, the rate of heat storage in the heat storage material 61 will be slower than the planned rate of heat storage, so the actuator control unit 95 controls the opening of the first expansion valve 81 to increase the amount of refrigerant discharged from the compressor 4 that flows into the heat storage heat exchanger 6 (ST47).

[0057] (Continued from main flow) While the thermal storage heating operation is in progress, the control unit 9 determines whether or not defrosting is necessary for the outdoor heat exchanger 5, according to the pre-set conditions for transitioning to defrosting (ST5 in Figure 3). For example, the condition for starting defrosting is met when the temperature of the outdoor heat exchanger 5 meets a predetermined temperature condition (e.g., -6°C or lower when the outside temperature is 2°C). If defrosting is not necessary (ST5-NO), the system returns to ST1 and the thermal storage heating operation continues.

[0058] On the other hand, if the control unit 9 determines that the conditions for starting defrost heating operation have been met (ST5-YES), the defrost heating operation is started (ST6). As explained above, in defrost heating operation, heating operation is performed, and defrosting operation is performed using the heat stored in the thermal storage heat exchanger 6. While the defrost heating operation is being performed, the control unit 9 determines, based on a preset termination condition, whether or not the frost on the outdoor heat exchanger 5 has melted and the defrost heating operation can be terminated (ST7). As an example of a termination condition, the detection value of a temperature sensor (not shown) that detects the temperature of the refrigerant flowing through the outdoor heat exchanger 5 is above a predetermined temperature (for example, 16°C).

[0059] If the control unit 9 determines that the frost on the outdoor heat exchanger 5 has not melted sufficiently and the defrost heating operation cannot be terminated yet (ST7-NO), the ongoing defrost heating operation will continue. On the other hand, if the control unit 9 determines that the defrost heating operation can be terminated (ST7-YES), the defrost heating operation will be terminated (ST8). Although not shown in the flowchart in Figure 3, the heating and heat storage operation may be restarted after the defrost heating operation has ended.

[0060] (Summary of the first embodiment) As described above, the refrigeration cycle device 1 of this embodiment controls the flow rate of the refrigerant used to heat the heat storage material 61 in accordance with the rise in the detected value of the heat storage material temperature sensor 24 by controlling the flow rate control valve (first expansion valve 81), and restricts the adjustment of the flow rate of the refrigerant flowing into the heat storage heat exchanger 6 when the detected value of the heat storage material temperature sensor 24 is in the latent heat range. That is, when the detected value of the heat storage material temperature sensor 24 is in the sensible heat range, which is outside the latent heat range, a sensible heat range control mode is executed, which adjusts the flow rate of the refrigerant in accordance with the rise in the detected value, and when the detected value is in the latent heat range, a latent heat range control mode is executed, which restricts the flow rate of the refrigerant more than when the sensible heat range control mode is executed. This prevents excessive flow of refrigerant to heat the heat storage material 61 when it is in the hot range, and ensures that the amount of refrigerant used for heating is secured, so that comfort can be maintained while appropriately heating the heat storage material 61.

[0061] It should be noted that the present invention is not limited to the embodiments described above, but merely illustrates one example, and the components may be modified and implemented without departing from the spirit of the invention. For example, in this embodiment, the flow control valve in the present invention is the first expansion valve 81, but the second expansion valve 82 may also be the object of control.

[0062] Furthermore, in the above embodiment, the opening degree of the first expansion valve 81 is controlled so that the flow rate of the refrigerant becomes a predetermined flow rate in the latent heat range control mode. However, the opening degree of the first expansion valve 81 may also be controlled so that the flow rate of the refrigerant becomes constant. [Examples]

[0063] Figure 7 is a flowchart showing the control mode of the refrigeration cycle device 1 according to the second embodiment of the present invention. Specifically, in this embodiment, the only difference from the first embodiment is that in the operation described in Figure 3, the "latent heat range control mode" of ST3 is replaced with the operation described in Figure 7.

[0064] (Figure 7: Subroutine_Latent Heat Range Control Mode) In ST51 of Figure 7, the control unit 9 obtains the heat storage condensation pressure using the parameter detection unit 91. Based on the obtained heat storage condensation pressure, the control unit 9 can estimate the condensation temperature of the refrigerant flowing through the heat storage heat exchanger 6 (hereinafter referred to as the heat storage condensation temperature Tstc). Then, the control unit 9 calculates the temperature difference ΔT, which is the value obtained by subtracting the heat storage material temperature Tstm from the calculated heat storage condensation temperature Tstc (ST52). Although ST51 and ST52 are shown as a single step in the flowchart for convenience, in reality, the heat storage condensation pressure is obtained and the temperature difference is calculated continuously using the parameter detection unit 91. The calculated temperature difference ΔT is stored in the storage unit 93 each time.

[0065] Subsequently, the determination unit 94 determines whether the value obtained by subtracting the previously calculated temperature difference ΔTn-1 (for example, 1 minute ago) from the latest temperature difference ΔTn is 0 or not (ST53). Specifically, the setting unit 92 stores the temperature difference ΔT calculated by the setting unit 92 in the storage unit 93 in association with the detection time information, and makes a determination based on the value obtained by subtracting the past temperature difference ΔTn-1 (for example, 60 seconds ago) stored in the storage unit 93 from the current temperature difference ΔTn calculated by the setting unit 92. If the value is 0 (ST53-YES), the operation of this flow ends and proceeds to ST5 in Figure 3.

[0066] On the other hand, if the value is not 0 (ST53-NO), it is determined whether the value is less than 0 (ST54). If the value is less than 0 (ST54-YES), the actuator control unit 95 controls the opening of the first expansion valve 81 by a predetermined amount (e.g., +2 to 5 pls) in the direction of opening from the current opening (ST55). After that, the operation of this flow ends and proceeds to ST5 in Figure 3. If the value is less than 0, it can be determined that the amount of heat supplied by the refrigerant to the heat storage material 61 is insufficient. Therefore, the opening of the first expansion valve 81 is increased to increase the flow rate so that the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger 6 and the temperature of the heat storage material 61 remains constant.

[0067] On the other hand, if the value is not less than 0 (ST54-NO), the actuator control unit 95 controls the opening of the first expansion valve 81 by a predetermined amount (e.g., -2 to 5 pls) in the direction of closing it from its current opening (ST56). After that, the operation of this flow ends and proceeds to ST5 in Figure 3. If the value is not 0 and not less than 0, i.e., greater than 0, it can be determined that the amount of heat supplied by the refrigerant to the heat storage material 61 is excessive. Therefore, the opening of the first expansion valve 81 is reduced to decrease the flow rate so that the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger 6 and the temperature of the heat storage material remains constant. As a result, during the heating and heat storage operation between the end of the previous defrosting operation and the start of the next defrosting operation, sufficient heat for use in the subsequent defrosting operation can be stored in the heat storage heat exchanger 6.

[0068] (Summary of the second embodiment) As described above, the refrigeration cycle device 1 according to this embodiment controls the opening of the flow control valve so that the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger 6 and the temperature of the heat storage material 61 remains constant when the detected value of the heat storage material temperature sensor 24 is in the latent heat range. This suppresses the decrease in the amount of refrigerant supplied to the indoor heat exchanger 10 and suppresses the decrease in heating capacity. Therefore, heat storage can be performed while suppressing a decrease in comfort.

[0069] In ST53 of this embodiment, it was determined whether the value obtained by subtracting the previously calculated temperature difference (for example, 1 minute ago) from the latest temperature difference was 0 or not, but it is not limited to this. For example, it may be determined whether the value obtained by subtracting a predetermined value from the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger 6 and the temperature of the heat storage material 61 is 0 or not. This predetermined value is determined in advance by testing or the like and stored in the memory unit (for example, 5°C). Similarly, in ST54, it was determined whether the value obtained by subtracting the previously calculated temperature difference (for example, 1 minute ago) from the latest temperature difference was less than 0, but it may also be determined whether the value obtained by subtracting a predetermined value from the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger 6 and the temperature of the heat storage material 61 is less than 0. [Explanation of symbols]

[0070] 1 Refrigeration cycle unit, 2 Outdoor unit, 3 Indoor unit, 4 Compressor, 5 Outdoor heat exchanger, 6 Thermal storage heat exchanger, 71 First switching valve, 72 Second switching valve, 81 Flow control valve (first expansion valve), 82 Second expansion valve, 83 Third expansion valve, 9 Control unit, 91 Parameter detection unit, 92 Setting unit, 93 Memory unit, 94 Judgment unit, Actuator control unit, 10 Indoor heat exchanger, 12 Discharge path, 13 Intake path, 14 Bypass path, 15 Branch path, 16 First junction point, 17 Branch point, 18 Junction path, 19 Second junction point, 20 Third junction point, 21 Discharge temperature sensor, 22 Indoor heat exchanger temperature sensor, 23 Outdoor heat exchanger temperature sensor, 24 Thermal storage material temperature sensor, 25 Outdoor temperature sensor, 26 Thermal storage heat exchanger pressure sensor, 31 Compressor passage, 32 Condensation and evaporation passage, 33 Heat storage passage.

Claims

1. Compressor and, An indoor heat exchanger that functions as a condenser, A heat storage heat exchanger that holds a heat storage material used in a temperature range including the latent heat range, which is a temperature range where phase changes occur, and heats the heat storage material with an incoming refrigerant, A heat storage material temperature sensor for detecting the temperature of the heat storage material, A first flow path connected to the indoor heat exchanger and guiding the refrigerant flowing into the indoor heat exchanger, A second flow path branches off from the first flow path and is connected to the heat storage heat exchanger, and guides the refrigerant flowing into the heat storage heat exchanger, A flow control valve installed in the second flow path controls the flow rate of the refrigerant circulating through the heat storage heat exchanger, A refrigeration cycle device comprising: a control unit that controls the flow rate adjustment valve to adjust the flow rate of the refrigerant in accordance with the rise in the detected value of the heat storage material temperature sensor, and limits the adjustment of the flow rate of the refrigerant flowing into the heat storage heat exchanger when the detected value of the heat storage material temperature sensor is in the latent heat range.

2. The refrigeration cycle apparatus according to claim 1, wherein the control unit determines that the temperature of the heat storage material is in the latent heat range when the amount of increase per unit time of the detected value of the heat storage material temperature sensor is less than or equal to a threshold.

3. The refrigeration cycle apparatus according to claim 1, wherein the control unit determines that the temperature of the heat storage material is within the latent heat range when the detected value of the heat storage material temperature sensor falls within the melting point temperature range of the heat storage material that has been stored in advance.

4. The refrigeration cycle apparatus according to claim 1, wherein the control unit controls the opening of the flow rate control valve so that the flow rate of refrigerant flowing into the heat storage heat exchanger remains constant when the detected value of the heat storage material temperature sensor is within the latent heat range.

5. The refrigeration cycle apparatus according to claim 4, wherein the control unit controls the opening of the flow control valve so that the flow rate of refrigerant flowing into the heat storage heat exchanger becomes a predetermined flow rate when the detected value of the heat storage material temperature sensor is within the latent heat range.

6. The refrigeration cycle apparatus according to claim 5, wherein the control unit controls the opening degree of the flow control valve so that the opening degree corresponds to the rotational speed of the compressor.

7. The refrigeration cycle apparatus according to claim 1, wherein the control unit controls the opening of the flow rate control valve so that the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger and the temperature of the heat storage material remains constant when the value detected by the heat storage material temperature sensor is within the latent heat range.

8. The refrigeration cycle apparatus according to claim 7, wherein the control unit controls the opening of the flow rate control valve so that the temperature difference between the condensation temperature of the refrigerant flowing into the heat storage heat exchanger and the temperature of the heat storage material becomes a predetermined temperature difference when the value detected by the heat storage material temperature sensor is within the latent heat range.

9. The refrigeration cycle apparatus according to claim 8, further comprising a heat storage heat exchanger pressure sensor for detecting the pressure of the refrigerant flowing into the heat storage heat exchanger, and calculating the pressure of the refrigerant flowing into the heat storage heat exchanger from the value detected by the heat storage heat exchanger pressure sensor.

10. The refrigeration cycle apparatus according to claim 1, wherein the control unit controls the flow rate adjustment valve so that the amount of increase in the detected value of the heat storage material temperature sensor follows a predetermined slope when the detected value of the heat storage material temperature sensor is not within the latent heat range.

11. The refrigeration cycle apparatus according to claims 1 to 10, wherein the flow control valve is provided in the second flow path to the extent that it branches off from the first flow path and is connected to the heat storage heat exchanger.

12. The refrigeration cycle apparatus according to claims 1 to 10, wherein the flow control valve is provided in the second flow path extending from the heat storage heat exchanger toward an outdoor heat exchanger that functions as an evaporator.

13. The refrigeration cycle apparatus according to claim 1, wherein the control unit executes a sensible heat range control mode to adjust the flow rate of the refrigerant in accordance with the increase in the detected value when the value detected by the heat storage material temperature sensor is in the sensible heat range, which is outside the latent heat range, and executes a latent heat range control mode to restrict the flow rate of the refrigerant more than when the sensible heat range control mode is executed when the detected value is in the latent heat range.

14. The refrigeration cycle apparatus according to claim 13, wherein the control unit controls the opening degree of the flow control valve based on the temperature of the heat storage material, the condensation temperature of the indoor heat exchanger, and the ambient temperature when the sensible heat range control mode is executed.

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