Refrigeration cycle device and method for controlling the refrigeration cycle device

Abstract

A refrigeration cycle device and a control method for a refrigeration cycle device are provided that can suppress a decrease in comfort for a user even when an operation mode is switched. [Solution] A refrigerant circuit C that circulates a refrigerant is connected to a compressor 1 that compresses the refrigerant, an indoor heat exchanger 2 that exchanges heat between the indoor air and the refrigerant, an indoor fan 21 that passes the indoor air through the indoor heat exchanger 2, an outdoor heat exchanger 3 that exchanges heat between the outdoor air and the refrigerant, a heat storage heat exchanger 4 that exchanges heat between a heat storage material and the refrigerant, and multiple switching valves 6 that switch the refrigerant circulation path in the refrigerant circuit C between a heating operation in which at least the indoor heat exchanger 2 functions as a condenser and a defrosting operation in which at least the outdoor heat exchanger 3 functions as a condenser, and is equipped with a control device 7 that controls the indoor fan 21 and the switching valve 6, and the control device 7 switches between the heating operation and the defrosting operation and changes the rotation speed of the indoor fan.

Description

[Technical field]

[0001] An embodiment of the present invention relates to a refrigeration cycle device and a control method for a refrigeration cycle device. [Background technology]

[0002] Generally, when an air conditioner is in heating operation, a low-temperature refrigerant flows through the outdoor heat exchanger. For this reason, when the outdoor air temperature is below freezing, for example, if the temperature of the refrigerant falls below the dew point of the outdoor air, frost will form on the outdoor heat exchanger, making it difficult to exchange heat with the outdoor air. Therefore, when the air conditioner is in heating operation, a defrosting operation is periodically performed to remove frost from the outdoor heat exchanger.

[0003] Such a defrosting operation is necessary for the operation of an air conditioner, and typically, the defrosting operation is performed by interrupting the heating operation. Specifically, when starting the defrosting operation, the refrigerant circuit is switched so that the refrigerant discharged from the compressor is directly supplied to the outdoor heat exchanger, and the outdoor heat exchanger is made to function as a condenser to melt the frost and perform defrosting. In the defrosting operation, the high-temperature refrigerant supplied to the outdoor heat exchanger for defrosting becomes low temperature by melting the frost, and the low-temperature refrigerant flows into the indoor heat exchanger.

[0004] When such a defrosting operation is performed, the heating operation is stopped and the indoor temperature gradually drops during the defrosting operation, which reduces the comfort of the user. Therefore, for example, as shown in the following Patent Document 1, a heat storage device is arranged in the refrigeration circuit separately from the indoor heat exchanger, and heat is stored in the heat storage device during the heating operation (hereinafter, such an operating mode is appropriately referred to as "heat storage heating operation").

[0005] A method is considered in which the heat stored in the heat storage device is used for defrosting during the defrosting operation to continue the heating operation even during the defrosting operation (hereinafter, such an operating mode is referred to as "defrosting heating operation" as appropriate). This method makes it possible to prevent a drop in the indoor temperature caused by the temporary stop of the heating operation for the defrosting operation, and maintain the comfort of the user. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-017738 A Summary of the Invention [Problem to be solved by the invention]

[0007] In an air conditioner equipped with such a heat storage device, for example, when switching from heat storage heating operation to defrost heating operation, the heat exchanger that plays the role of the condenser is partially changed. That is, in heat storage heating operation, the indoor heat exchanger and the heat exchanger of the heat storage device are condensers, and the outdoor heat exchanger plays the role of an evaporator. In contrast, in defrost heating operation, the indoor heat exchanger and the outdoor heat exchanger play the role of condensers, and the heat exchanger of the heat storage device plays the role of an evaporator.

[0008] Therefore, when the operation mode is changed from the heat storage heating operation to the defrosting and heat storage operation, the internal volume of the refrigerant passage of the heat exchanger, which serves as a condenser, increases. This will be explained with reference to Fig. 11. Fig. 11 is an explanatory diagram showing an example of the change in the internal volume of the refrigerant passage of the heat exchanger when the operation mode is changed in the refrigeration cycle device.

[0009] In Fig. 11, two graphs are shown, one above the other and one below the large downward arrow in the center of the drawing. The upper graph shows the internal volume of the refrigerant flow path of the heat exchanger that serves as a condenser and an evaporator during heat storage heating operation. On the other hand, the lower graph shows the internal volume of the refrigerant flow path of the heat exchanger that serves as a condenser and an evaporator during defrost heating operation.

[0010] In each graph, the vertical axis indicates the "heat exchanger serving as a condenser" in the upper row and the "heat exchanger serving as an evaporator" in the lower row, while the horizontal axis indicates the "internal volume of the refrigerant flow path."

[0011] Furthermore, each graph shows the internal volume of the refrigerant flow path of three types of heat exchangers that make up the air conditioner: the "indoor heat exchanger," the "outdoor heat exchanger," and the "heat storage device heat exchanger (represented as the "heat storage heat exchanger" in Figure 11)."

[0012] As mentioned above, the horizontal axis of the graph indicates the internal volume of the refrigerant flow path, and therefore the internal volume of the refrigerant flow path of each heat exchanger is shown extending from the left to the right in the graph. For example, the upper part of Fig. 11 shows the internal volume of the refrigerant flow path of each heat exchanger during heat storage heating operation. During heat storage heating operation, the "indoor heat exchanger" and the "heat storage heat exchanger" function as condensers. Meanwhile, the "outdoor heat exchanger" functions as an evaporator.

[0013] Therefore, in the graph shown at the top of Fig. 11, the section "heat exchanger acting as a condenser" shows the internal volume of the refrigerant flow path of the "indoor heat exchanger" and the "heat storage heat exchanger", while the section "heat exchanger acting as an evaporator" shows the internal volume of the refrigerant flow path of the "outdoor heat exchanger".

[0014] The graph at the top of Figure 11 shows that the internal volume of the refrigerant passage of the heat exchanger that functions as a condenser is the internal volume of the refrigerant passage of the indoor heat exchanger plus the internal volume of the refrigerant passage of the heat storage heat exchanger. On the other hand, since the only heat exchanger that functions as an evaporator is the outdoor heat exchanger, the internal volume of the refrigerant passage of the heat exchanger that functions as an evaporator is equal to the internal volume of the refrigerant passage of the outdoor heat exchanger.

[0015] When comparing the internal volume of the refrigerant passage of the heat exchanger acting as a condenser with that of the heat exchanger acting as an evaporator, it is found that the internal volume of the refrigerant passage of the heat exchanger acting as a condenser is larger than that of the refrigerant passage of the heat exchanger acting as an evaporator. In this state, when the air conditioner transitions from heat storage heating operation to defrost heating operation, the heat exchanger acting as the condenser is changed from that in heat storage heating operation, so that the internal volume of the refrigerant passage of the heat exchanger acting as a condenser and the internal volume of the refrigerant passage of the heat exchanger acting as an evaporator change.

[0016] As described above, the graph at the bottom of Fig. 11 is a graph showing the internal volume of the refrigerant passage of each heat exchanger during defrost heating operation. When defrost heating operation is performed, the heat exchangers that function as condensers are the indoor heat exchanger and the outdoor heat exchanger. On the other hand, the heat exchanger that functions as an evaporator is only the heat storage heat exchanger. Looking at the internal volumes of the refrigerant passages in each case, it can be seen that the internal volume of the refrigerant passage of the heat exchanger that functions as a condenser is much larger than the internal volume of the refrigerant passage of the heat exchanger that functions as an evaporator.

[0017] When comparing the internal volume of the refrigerant flow path of the heat exchanger that acts as a condenser during heat storage heating operation with the internal volume of the refrigerant flow path of the heat exchanger that acts as a condenser during defrost heating operation, the internal volume of the refrigerant flow path of the heat exchanger that acts as a condenser in the latter is larger than the former by the amount of arrow A.

[0018] In this way, for example, as shown in Fig. 11, by switching from heat storage heating operation to defrost heating operation, the internal volume of the refrigerant passage of the heat exchanger that functions as a condenser increases suddenly. When the internal volume of the refrigerant passage increases due to a change in the operating mode in this way, the amount of high-density liquid-phase refrigerant in the condenser increases, and the pressure of the refrigerant flowing inside the refrigerant circuit decreases as the refrigerant volume decreases. When the refrigerant pressure decreases, the condensing temperature in the condenser also decreases.

[0019] This will be explained with reference to Fig. 12. Fig. 12 is a graph showing the relationship between the rotation speed of the indoor fan and the condensing temperature when the indoor fan is controlled while changing the operating mode in a conventional refrigeration cycle device.

[0020] In Fig. 12, the horizontal axis represents time, and the operation mode is switched at a certain time on the horizontal axis. Here, the operation mode before the switch is heat storage heating operation, and the operation mode after the switch is defrost heating operation. Among the lines extending from the left to the right of the graph over time, the upper solid line represents the rotation speed (air volume) of the indoor fan provided in the indoor unit. Meanwhile, the lower dashed line represents the condensation temperature.

[0021] When the operation mode is switched from the heat storage heating operation to the defrost heating operation, the internal volume of the refrigerant passage of the heat exchanger that functions as a condenser increases, as shown in Fig. 11. Therefore, the pressure of the refrigerant flowing in the refrigerant circuit decreases, and the condensation temperature also decreases. This is shown by the fact that the condensation temperature shown by the dashed line in Fig. 12 decreases at the boundary where the operation mode is switched.

[0022] On the other hand, since the rotation speed of the indoor fan is controlled based on the setting information input via a remote control or the suction temperature, the rotation speed of the indoor fan does not change immediately even when the operation mode is switched from the heat storage heating operation to the defrost heating operation. Specifically, the rotation speed of the indoor fan does not decrease until the condensation temperature falls below a predetermined condensation temperature value at which a feeling of cool air is felt, so the rotation speed of the indoor fan does not follow the decrease in the condensation temperature. Therefore, the indoor fan continues to rotate at the rotation speed during the heat storage heating operation for a while, and cool air is supplied to the room.

[0023] Whether the room is in heat storage heating mode or defrost heating mode, the indoor heat exchanger still functions as a condenser, and when the condensation temperature drops as a result of the change in operating mode, cold air is supplied to the room that is being heated. This supply of cold air to the room may reduce the comfort of the user, especially during heating operation.

[0024] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a refrigeration cycle device and a control method for a refrigeration cycle device that can suppress a decrease in comfort for the user even when the operating mode is changed. [Means for solving the problem]

[0025] A refrigeration cycle device according to one aspect of the present invention includes a refrigerant circuit that circulates a refrigerant, and is connected to a compressor that compresses the refrigerant, an indoor heat exchanger that exchanges heat between indoor air and the refrigerant, an indoor fan that passes the indoor air through the indoor heat exchanger, an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant, a heat storage heat exchanger that exchanges heat between a heat storage material and the refrigerant, and a plurality of switching valves that switch the circulation path of the refrigerant in the refrigerant circuit between a heating operation in which at least only the indoor heat exchanger functions as a condenser and a defrosting operation in which at least the outdoor heat exchanger functions as a condenser; A storage unit that stores information regarding the internal volume of each of the refrigerant flow paths of at least the indoor heat exchanger and the outdoor heat exchanger; The indoor fan and the control device that controls the switching valve are provided, and the control device switches between the heating operation and the defrosting operation. When To, Based on information about the internal volume of the refrigerant flow path Vary the rotation speed of the indoor fan.

[0026] A control method for a refrigeration cycle device according to one aspect of the present invention includes a refrigerant circuit that circulates a refrigerant, which is connected to a compressor that compresses the refrigerant, an indoor heat exchanger that exchanges heat between indoor air and the refrigerant, an indoor fan that passes the indoor air through the indoor heat exchanger, an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant, a heat storage heat exchanger that exchanges heat between a heat storage material and the refrigerant, and a plurality of switching valves that switch a refrigerant circulation path in the refrigerant circuit between a heating operation in which at least only the indoor heat exchanger functions as a condenser and a defrosting operation in which at least the outdoor heat exchanger functions as a condenser, and a control device that controls the indoor fan and the switching valve, the control device including a step of determining whether to switch an operation mode between the heating operation and the defrosting operation, a step of switching the switching valve when it is determined that the operation mode is to be switched, and a step of controlling to change the rotation speed of the indoor fan in accordance with the operation mode after switching the rotation speed of the indoor fan. The rotation speed of the indoor fan is set based on information on the internal volume of the refrigerant flow path of at least the indoor heat exchanger and the outdoor heat exchanger. do. Effect of the Invention

[0027] According to the present invention, even if the driving mode is changed, the deterioration of comfort for the user can be suppressed. [Brief description of the drawings]

[0028] [Figure 1] 1 is a refrigerant circuit diagram of a refrigeration cycle device according to an embodiment of the present invention. [Diagram 2] 1 is a block diagram showing an internal configuration of a control device in a refrigeration cycle apparatus according to an embodiment of the present invention. [Diagram 3] 11 is a graph showing the relationship between the rotation speed of the indoor fan and the condensation temperature when the indoor fan is controlled when the operation mode is changed in the refrigeration cycle apparatus according to the embodiment of the present invention. [Figure 4] 1 is a refrigerant circuit diagram showing a flow of a refrigerant when a refrigeration cycle device according to an embodiment of the present invention performs a cooling operation. [Diagram 5] 1 is a refrigerant circuit diagram showing a flow of a refrigerant when a refrigeration cycle device according to an embodiment of the present invention performs a heat storage heating operation. [Figure 6] 1 is a refrigerant circuit diagram showing a flow of a refrigerant when a refrigeration cycle device according to an embodiment of the present invention performs a defrosting heating operation. [Figure 7] 1 is a refrigerant circuit diagram showing a flow of a refrigerant when a refrigeration cycle device according to an embodiment of the present invention performs a heat storage heating operation. [Figure 8] 1 is a refrigerant circuit diagram showing a flow of a refrigerant when a refrigeration cycle device according to an embodiment of the present invention performs a normal heating operation. [Figure 9] 5 is a flowchart showing a control flow when an operation mode is changed in the refrigeration cycle apparatus according to the embodiment of the present invention. [Figure 10] 5 is a flowchart showing a control flow when an operation mode is changed in the refrigeration cycle apparatus according to the embodiment of the present invention. [Figure 11]FIG. 4 is an explanatory diagram showing an example of a change in the internal volume of a refrigerant flow path of a heat exchanger when an operating mode is changed in a refrigeration cycle device. [Figure 12] 11 is a graph showing the relationship between the rotation speed of the indoor fan and the condensation temperature when the indoor fan is controlled while changing the operation mode in a conventional refrigeration cycle device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The structure of a refrigeration cycle apparatus S according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a refrigerant circuit diagram of the refrigeration cycle apparatus S according to the embodiment of the present invention. The refrigeration cycle apparatus S includes a refrigerant circuit C in which a compressor 1, an indoor heat exchanger 2, an outdoor heat exchanger 3, a heat storage heat exchanger 4, an expansion valve 5 (51, 52, 53), and a switching valve 6 (61, 62) are connected and which circulates the refrigerant. The refrigeration cycle apparatus S also includes a control device 7 that controls the expansion valve 5 and the switching valve 6.

[0030] Here, the refrigerant circuit C of the refrigeration cycle apparatus S in the embodiment of the present invention will be described with reference to Fig. 1. The refrigerant circuit C is composed of each device such as the compressor 1 described above, and a flow path through which the refrigerant flows that connects these devices. For example, when the refrigeration cycle apparatus S performs a normal heating operation described below, the refrigerant discharged from the compressor 1 flows through the indoor heat exchanger 2 and the outdoor heat exchanger 3 in this order, and is then sucked into the compressor 1. A first switching valve 61 is provided in the flow path connecting the compressor 1 and the indoor heat exchanger 2 during the heating operation, and a third expansion valve 53 is provided in the flow path connecting the indoor heat exchanger 2 and the outdoor heat exchanger 3.

[0031] In addition, a first expansion valve 51 and a second switching valve 62 are provided in this order in the flow path connecting the compressor 1 and the heat storage heat exchanger 4 during the heat storage heating operation. In addition, a second expansion valve 52 is provided in the flow path connecting the heat storage heat exchanger 4 and the junction C1. Therefore, for example, when the refrigeration cycle device S performs a heat storage heating operation described later, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 and the heat storage heat exchanger 4. The refrigerant flowing out of the heat storage heat exchanger 4 flows into the outdoor heat exchanger 3 via the second expansion valve 52 and the junction C1 provided in the flow path between the second expansion valve 52 and the outdoor heat exchanger 3, and is then sucked into the compressor 1.

[0032] The first switching valve 61 is controlled by a control device 7 described later to switch between flowing the refrigerant discharged from the compressor 1 to the indoor heat exchanger 2 and flowing the refrigerant to a bypass circuit B1 connected to a flow path between the first expansion valve 51 and the second switching valve 62. The bypass circuit B1 is provided between the first switching valve 61 and the second switching valve 62. The bypass circuit B1 is provided with a check valve and the like so that the refrigerant flows only in the direction of the arrow as shown in FIG.

[0033] As described above, the bypass circuit B1 in the refrigerant circuit C shown in Fig. 1 is provided with a check valve so that the refrigerant flows only in the direction of the arrow. However, it is also possible to use an on-off valve such as a solenoid valve instead of the check valve in the bypass circuit B1. By using an on-off valve in this manner, it is possible to flow the refrigerant from the second switching valve 62 to the first switching valve 61, as in the heat storage heating operation described later.

[0034] When the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2, the bypass circuit B1 is connected to the suction side of the compressor 1. On the other hand, when the refrigerant discharged from the compressor 1 flows into the bypass circuit B1 that connects to the flow path between the first expansion valve 51 and the second switching valve 62, the indoor heat exchanger 2 is connected to the suction side of the compressor 1 except in the case of the heat storage heating operation.

[0035] The second switching valve 62 is controlled by the control device 7 to switch between flowing the refrigerant discharged from the compressor 1 to the heat-storage heat exchanger 4 and flowing to the outdoor heat exchanger 3. When the refrigerant discharged from the compressor 1 flows to the heat-storage heat exchanger 4, the outdoor heat exchanger 3 and the suction side of the compressor 1 are connected. On the other hand, when the refrigerant discharged from the compressor 1 flows to the outdoor heat exchanger 3, the heat-storage heat exchanger 4 and the suction side of the compressor 1 are connected.

[0036] The compressor 1 compresses the refrigerant circulating through the refrigerant circuit C. The indoor heat exchanger 2 exchanges heat between the indoor air and the refrigerant. The outdoor heat exchanger 3 exchanges heat between the outdoor air and the refrigerant. Although explanations of the types of the compressor 1, the indoor heat exchanger 2, and the outdoor heat exchanger 3 will be omitted here, various types of equipment can be adopted.

[0037] In addition, the indoor heat exchanger 2 in the embodiment of the present invention is provided with an indoor fan 21 that passes indoor air through the indoor heat exchanger 2. In addition, the outdoor heat exchanger 3 is provided with an outdoor fan 31 that passes outdoor air through the outdoor heat exchanger 3.

[0038] The heat storage heat exchanger 4 is a heat exchanger in which heat is exchanged between the heat storage material and the refrigerant passing through the heat storage heat exchanger 4. The heat storage heat exchanger 4 is, for example, a fin-and-tube type heat exchanger. The heat storage heat exchanger 4 is disposed in a heat storage container filled with a heat storage material.

[0039] The heat storage material may be liquid or solid, as long as it can exchange heat with the refrigerant flowing inside the heat storage heat exchanger 4 and store heat. Therefore, for example, when the heat storage material is liquid, the heat storage heat exchanger 4 is immersed in the heat storage material filled in the heat storage container. In other words, the heat storage heat exchanger 4 is surrounded by the heat storage material. The heat supplied from the refrigerant is stored in this heat storage material, and the stored heat is used, for example, for defrost heating operation or heat storage heating operation, as described later.

[0040] In the heat exchanger, the volume of the heat transfer pipes (from the inlet to the outlet) through which the refrigerant flows is referred to as the "internal volume of the refrigerant flow path," and the internal volume of the refrigerant flow path of the heat storage heat exchanger 4 is smaller than the internal volume of the refrigerant flow path of the outdoor heat exchanger 3. This is because in the heat storage heat exchanger 4, the refrigerant exchanges heat with the heat storage material, and in the outdoor heat exchanger 3, the refrigerant exchanges heat with the outside air.

[0041] That is, the specific heat of the heat storage material is larger than that of the air in the object in which heat exchange with the refrigerant takes place. Also, the amount of heat exchange is proportional to the temperature difference, i.e., the larger the temperature difference, the larger the heat exchange amount. Therefore, since the heat storage heat exchanger 4, which is easier to secure the temperature difference, can maintain the heat exchange performance even if it is smaller than the outdoor heat exchanger 3, the internal volume of the refrigerant flow path of the heat storage heat exchanger 4 is smaller than the internal volume of the refrigerant flow path of the outdoor heat exchanger 3.

[0042] The refrigeration cycle apparatus S according to the embodiment of the present invention is provided with a plurality of expansion valves 5. Specifically, three expansion valves are provided, and a first expansion valve 51 is provided upstream in the refrigerant flow direction when the heat storage heat exchanger 4 functions as a condenser.

[0043] The second expansion valve 52 is provided between the heat storage heat exchanger 4 and the above-mentioned junction C1 in the refrigerant circuit C. That is, the second expansion valve 52 is provided downstream in the direction in which the refrigerant flows when the heat storage heat exchanger 4 functions as a condenser. The third expansion valve 53 is provided in a flow path connecting the indoor heat exchanger 2 and the outdoor heat exchanger 3. That is, the third expansion valve 53 is provided downstream in the direction in which the refrigerant flows when the indoor heat exchanger 2 functions as a condenser.

[0044] As described above, the switching valve 6 is composed of the first switching valve 61 and the second switching valve 62. The first switching valve 61 is provided between the compressor 1 and the indoor heat exchanger 2. The second switching valve 62 is provided between the compressor 1 and the outdoor heat exchanger 3 or the heat storage heat exchanger 4.

[0045] The first switching valve 61 switches between flowing the refrigerant to the indoor heat exchanger 2 and flowing to the bypass circuit B1. On the other hand, the second switching valve 62 switches between flowing the refrigerant to the heat storage heat exchanger 4 and flowing to the outdoor heat exchanger 3.

[0046] In the following, when these three expansion valves 51, 52, and 53 are collectively described, they are referred to as "expansion valve 5," and when each expansion valve is described individually, they are referred to by their respective names. Similarly, when these two switching valves 61 and 62 are collectively described, they are referred to as "switching valve 6," and when each switching valve is described individually, they are referred to by their respective names.

[0047] Furthermore, in the refrigeration cycle apparatus S according to the embodiment of the present invention, the heating operation is not stopped even when the defrosting operation is performed on the outdoor heat exchanger 3, and a defrosting heating operation is executed in which the heating operation is performed in parallel with the defrosting operation.

[0048] The control device 7 controls the opening degree of the plurality of expansion valves 5. The control device 7 controls the opening degree of each expansion valve, thereby adjusting the flow rate of the refrigerant flowing through the refrigerant circuit C. As described above, the control device 7 switches the flow of the refrigerant circulating through the refrigerant circuit C by switching the plurality of switching valves 6.

[0049] In this way, the control device 7 performs, for example, a heating and heat storage operation in which a heating operation and a heat storage operation are performed in parallel by controlling the multiple expansion valves 5 and the multiple switching valves 6. In addition, for example, the control device 7 also controls a defrosting operation for the outdoor heat exchanger 3 that is performed in parallel with the heating operation.

[0050] In addition, for example, when the operation is switched from heat storage heating operation to defrost heating operation, the above-mentioned multiple expansion valves 5 and switching valve 6 are controlled, and the control device 7 controls the indoor fan 21 to change its rotation speed.

[0051] Next, the contents of control by the control device 7 will be described in more detail. As described above, for example, when the operating mode is switched from the heat storage heating operation to the defrost heating operation, the internal volume of the refrigerant flow path of the heat exchanger that serves as a condenser increases. Therefore, the pressure of the refrigerant flowing in the refrigerant circuit decreases, and the condensation temperature also decreases. However, in the case of the conventional method of controlling the indoor fan 21, the rotation speed of the indoor fan 21 does not decrease until the condensation temperature becomes equal to or lower than a predetermined condensation temperature value at which a feeling of cool air is felt.

[0052] In this way, since the rotation speed of the indoor fan 21 was not changed according to the lowered condensation temperature, the rotation speed of the indoor fan does not follow the lowering of the condensation temperature. Therefore, even if the operation mode is switched from the heat storage heating operation to the defrost heating operation, the indoor fan continues to rotate at the rotation speed during the heat storage heating operation for a while, and cool air continues to be supplied into the room.

[0053] Therefore, in the control device 7 in the embodiment of the present invention, when the operating state of the refrigeration cycle apparatus S is switched from the heat-storage heating operation to the defrosting heating operation, the rotation speed of the indoor fan 21 is controlled to an appropriate rotation speed.

[0054] 2 is a block diagram showing an internal configuration of a control device 7 in a refrigeration cycle apparatus S according to an embodiment of the present invention. The control device 7 includes a determination unit 71, a storage unit 72, a calculation unit 73, and a switching control unit 74.

[0055] The determination unit 71 determines whether or not to switch between various operation modes such as cooling operation, heat storage heating operation, defrost heating operation, etc. In addition, for example, when the operation mode is switched from heat storage heating operation to defrost heating operation, the determination unit 71 controls the rotation speed of the indoor fan 21.

[0056] The storage unit 72 stores at least information regarding the internal volume of the refrigerant flow path of each of the indoor heat exchanger 2, the outdoor heat exchanger 3, and the heat storage heat exchanger 4. The information regarding the internal volume of the refrigerant flow path stored in the storage unit 72 may be stored in the storage unit 72 in any manner, for example, by storing each heat exchanger and the internal volume of each refrigerant flow path in a table in association with each other.

[0057] The calculation unit 73 calculates the sum of the internal volumes of all the condenser refrigerant flow paths of the heat exchangers functioning as condensers in each operation mode, based on the information on the internal volumes of the refrigerant flow paths stored in the storage unit 72. The sum of the internal volumes of the condenser refrigerant flow paths may be stored in advance in the storage unit 72. When the operation mode is switched, the switching control unit 74 controls the opening degree of the expansion valve 5 and the switching valve 6 based on instructions from the determination unit 71. It also switches the rotation speed of the indoor fan 21 in response to the switching of the operation mode.

[0058] Next, the function of each part of the control device 7 in the embodiment of the present invention will be described in more detail. When the operation mode is switched to the defrosting heating operation, the previous operation mode can be the heat storage heating operation, the heat storage heating operation, or the normal heating operation, as described later. Here, the case where the operation mode is switched from the heat storage heating operation to the defrosting heating operation will be described as an example.

[0059] The determination unit 71 determines whether or not to switch the operation state from the heat-storage heating operation to the defrosting heating operation when the refrigeration cycle apparatus S is performing the heat-storage heating operation. That is, for example, when the heat-storage heating operation is being performed, the determination unit 71 executes a determination as to whether or not a condition for starting the defrosting heating operation, which indicates that the defrosting heating operation is necessary, is satisfied.

[0060] Here, the condition for starting the defrosting heating operation can be, for example, the evaporation temperature of the refrigerant in the outdoor heat exchanger 3. In other words, when the evaporation temperature is equal to or lower than a preset temperature, there is a possibility of frost forming on the outdoor heat exchanger 3. Therefore, the determination unit 71 determines the start of the defrosting heating operation based on the evaporation temperature of the outdoor heat exchanger 3 during the heat storage heating operation.

[0061] When the determination unit 71 determines that the start condition for the defrosting heating operation is satisfied, it issues an instruction to the switching control unit 74 to switch the switching valve 6. That is, the second switching valve 62 is switched to switch the operation mode from the heat-storage heating operation in which the indoor heat exchanger 2 and the heat-storage heat exchanger 4 function as condensers and the outdoor heat exchanger 3 functions as an evaporator to the defrosting heating operation in which the indoor heat exchanger 2 and the outdoor heat exchanger 3 function as condensers and the heat-storage heat exchanger 4 functions as an evaporator.

[0062] Additionally, the determination unit 71 sets the rotation speed of the indoor fan 21 after the operation mode is switched from the heat-storage heating operation to the defrost heating operation in order to perform control to change the rotation speed of the indoor fan 21.

[0063] As explained using Fig. 11, when the operating mode is switched from the heat storage heating operation to the defrost heating operation, the heat exchanger that plays the role of the condenser changes from the heat storage heat exchanger 4 to the outdoor heat exchanger 3 (the indoor heat exchanger 2 continues to function as a condenser), and the amount of high-density liquid-phase refrigerant in the condenser increases. Therefore, the pressure of the refrigerant flowing inside the refrigerant circuit decreases as the volume of the refrigerant decreases. And when the refrigerant pressure decreases, the condensing temperature in the condenser also decreases.

[0064] In this case, if the indoor fan 21 is unable to keep up with the drop in condensation temperature and blows air into the room at the same rotation speed as during heat storage heating operation, cold air will be supplied to the heated room. Therefore, in order to avoid supplying cold air to the room in this way from the viewpoint of maintaining user comfort, the rotation speed of the indoor fan 21 is set by the method described below.

[0065] First, the determination unit 71 issues an instruction to the calculation unit 73 to calculate the rotation speed of the indoor fan 21 after the operation mode is switched to the defrost heating operation. Based on the instruction from the determination unit 71 and on the information related to the internal volume of the refrigerant flow path stored in the storage unit 72, the calculation unit 73 calculates the internal volume of the refrigerant flow path of the heat exchanger functioning as a condenser in each operation mode.

[0066] Here, "information regarding the internal volume of the refrigerant flow path" may include, for example, information regarding the internal volume of the refrigerant flow path of each of the indoor heat exchanger 2, the outdoor heat exchanger 3, and the heat storage heat exchanger 4. In addition, information regarding the internal volume of the refrigerant flow path of the entire condenser in a combination of heat exchangers that play the role of a condenser in each operation mode, and information such as the rotation speed of the indoor fan 21 linked to the combination of heat exchangers (operation mode) may be included.

[0067] For example, the condensers in the case of the heat-storage heating operation are the indoor heat exchanger 2 and the heat-storage heat exchanger 4. Therefore, the calculation unit 73 first calculates the internal volumes of the refrigerant flow paths of these heat exchangers that function as condensers in the heat-storage heating operation.

[0068] In addition, the internal volume of the refrigerant flow path of the heat exchanger that serves as a condenser in the defrosting heating operation, which is the operation mode after the switchover, is calculated. In the defrosting heating operation, the indoor heat exchanger 2 and the outdoor heat exchanger 3 serve as condensers, so the sum of the internal volumes of the refrigerant flow paths of these is calculated.

[0069] The calculation unit 73 then calculates the rate of change of the internal volume of the condenser refrigerant flow path after switching (the sum of the internal volume of the refrigerant flow path of the indoor heat exchanger 2 and the internal volume of the refrigerant flow path of the outdoor heat exchanger 3) relative to the internal volume of the condenser refrigerant flow path before switching the operating mode (the sum of the internal volume of the refrigerant flow path of the indoor heat exchanger 2 and the internal volume of the refrigerant flow path of the heat storage heat exchanger 4).

[0070] Then, the calculation unit 73 sets the rotation speed of the indoor fan 21 in the operating mode after the switching (here, defrosting and heating operation) based on a value obtained by multiplying the calculated rate of change by the rotation speed of the indoor fan 21 in the operating mode before the switching of the operating mode (here, defrosting and heating operation).

[0071] In addition to the method in which the determination unit 71 sets the rotation speed of the indoor fan 21 after the operation mode is switched based on the rate of change calculated by the calculation unit 73 in this manner, for example, the following method can also be adopted.

[0072] That is, when the judgment unit 71 determines that the conditions for starting the defrost heating operation are satisfied, the judgment unit 71 accesses the memory unit 72 and obtains information regarding the internal volume of the refrigerant flow path of each heat exchanger stored in the memory unit 72.

[0073] As described above, information on the internal volume of the refrigerant flow path of the entire condenser in the combination of heat exchangers that function as the condenser in each operation mode is stored in the memory unit 72. The determination unit 71 accesses the memory unit 72 to obtain information on the internal volume of the refrigerant flow path from the memory unit 72, and sets the rotation speed of the indoor fan 21 based on the information on the internal volume of the refrigerant flow path.

[0074] Using the method described above, the determination unit 71 sets a new rotation speed of the indoor fan 21. Then, based on the setting, it instructs the switching control unit 74 to switch the rotation speed of the indoor fan 21.

[0075] The switching control unit 74 executes, for example, switching of the switching valve 6 based on an instruction to switch the operation mode from the determination unit 71. Specifically, when the operation mode switches from the heat-storage heating operation to the defrost heating operation, the switching control unit 74 switches the second switching valve 62 so that the refrigerant discharged from the compressor 1 that had been flowing to the heat-storage heat exchanger 4 in the heat-storage heating operation flows to the outdoor heat exchanger 3.

[0076] FIG. 3 is a graph showing the relationship between the rotation speed of the indoor fan 21 and the condensation temperature when the indoor fan 21 is controlled while changing the operation mode in the refrigeration cycle apparatus S according to the embodiment of the present invention.

[0077] In Fig. 3, the horizontal axis represents time, and the operation mode is switched at a certain time on the horizontal axis. Here, the operation mode before the switch is heat storage heating operation, and the operation mode after the switch is defrost heating operation. Among the lines extending from the left to the right of the graph over time, the upper solid line represents the rotation speed (air volume) of the indoor fan provided in the indoor unit. Meanwhile, the lower dashed line represents the condensation temperature.

[0078] As explained above, when the operation mode is switched from the heat storage heating operation to the defrost heating operation, the internal volume of the refrigerant passage of the heat exchanger that serves as a condenser increases. Therefore, in the conventional control method, the pressure of the refrigerant flowing in the refrigerant circuit decreases, and the condensation temperature also decreases, as shown in Fig. 12.

[0079] On the other hand, in this embodiment, as described above, when the operating mode is switched from the heat storage heating operation to the defrost heating operation, the rotation speed of the indoor fan 21 is changed, that is, control is performed to reduce the rotation speed of the indoor fan 21. This control is shown as the rotation speed of the indoor fan 21 is reduced in accordance with the switching control of the second switching valve 62 by the switching control unit 74 shown by the dotted line parallel to the vertical axis in Fig. 3.

[0080] In this way, by changing the rotation speed of the indoor fan 21 in accordance with the switching of the operation mode, it is possible to prevent a large drop in the condensation temperature and to avoid the supply of cold air to the room, thereby maintaining the comfort of the user.

[0081] On the other hand, after the operation mode is switched from the heat storage heating operation to the defrost heating operation, the condensation temperature in the defrost heating operation is only slightly lower than the condensation temperature in the heat storage heating operation and shows an approximately constant value. In this way, by performing the process of reducing the rotation speed of the indoor fan 21 at approximately the same time as the operation mode is switched, the reduction in the condensation temperature is smaller than when the rotation speed of the indoor fan 21 is reduced after some time has passed since the operation mode was switched, at least as shown in Fig. 12.

[0082] In the above description, it is assumed that the heat storage heating operation is performed as the operation mode performed before the defrost heating operation is started. However, for example, the heating operation mode may be the heat storage heating operation, the heat storage heating operation, or the normal heating operation in addition to the heat storage heating operation.

[0083] As explained above, the heat stored in the heat storage heat exchanger 4 during the heat storage heating operation is used during the defrosting operation for the outdoor heat exchanger 3. In contrast, the heat storage heating operation is an operation mode in which the heat stored in the heat storage heat exchanger 4 is used for the heating operation.

[0084] The heat storage heating operation is an operation mode that is performed to satisfy the required heating capacity by using the heat stored in the heat storage heat exchanger 4 when, for example, the outdoor temperature is low and heat cannot be taken in by the outdoor heat exchanger 3. In this operation mode, as shown in Fig. 7 described later, only the indoor heat exchanger 2 serves as a condenser, and both the heat storage heat exchanger 4 and the outdoor heat exchanger 3 serve as evaporators.

[0085] Next, the normal heating operation is an operation mode in which, when the heating operation is performed, the refrigerant is not flowed through the heat storage heat exchanger 4. The amount of heat that can be stored in the heat storage heat exchanger 4 is determined by the type and capacity of the heat storage material. Therefore, for example, when heat is stored in the heat storage heat exchanger 4 by performing the heat storage heating operation, it is possible that the heat storage material cannot store any more heat.

[0086] When the heat storage heat exchanger 4 is in this state, the effect of heat storage cannot be expected even if the refrigerant is made to flow into the heat storage heat exchanger 4 to perform heat exchange, and it is therefore not necessary to make the refrigerant flow into the heat storage heat exchanger 4. Therefore, when performing heating operation in such a case, the operating mode in which the refrigerant is not made to flow into the heat storage heat exchanger 4 but only into the outdoor heat exchanger 3 is called normal heating operation.

[0087] Therefore, in normal heating operation, only the indoor heat exchanger 2 functions as a condenser, while the outdoor heat exchanger 3 functions as an evaporator. As for the heat storage heat exchanger 4, as shown in FIG. 8 described later, no refrigerant flows into the heat storage heat exchanger 4.

[0088] Even when the operating mode is switched from such heat storage heating operation or from normal heating operation to defrost heating operation, the rotation speed of the indoor fan 21 is set by the control device 7 as described above based on information regarding the internal volume of the refrigerant flow path of the heat exchanger that serves as a condenser.

[0089] It is assumed that the operation mode is switched from the various heating operations described above to the defrost heating operation. In the case of the defrost operation without the heating operation, there is no possibility that the indoor fan 21 supplies cold air to the room. Therefore, even if the control to change the rotation speed of the indoor fan 21 is not performed when the condensation temperature drops, the decrease in comfort felt by the user is considered to be less than that in the case of the defrost heating operation.

[0090] The functions of the components of the control device 7 of the refrigeration cycle apparatus S in the embodiment of the present invention have been described above. Next, the operation modes of the refrigeration cycle apparatus S will be described in order with reference to the circuit diagrams of the refrigeration cycle apparatus S in the embodiment of the present invention shown in Figs. 4 to 8.

[0091] In the circuit diagrams shown in Figures 4 to 8, refrigerant circuits C through which the refrigerant actually flows are indicated by solid lines. Meanwhile, refrigerant circuits C through which the refrigerant does not flow are indicated by dashed lines. The direction of the refrigerant flowing in the refrigerant circuit C is indicated by arrows.

[0092] First, the cooling operation will be described. Fig. 4 is a refrigerant circuit diagram showing the flow of refrigerant when the refrigeration cycle device S according to the embodiment of the present invention performs cooling operation. During cooling operation, the indoor heat exchanger 2 functions as an evaporator, and the outdoor heat exchanger 3 functions as a condenser. On the other hand, no refrigerant flows into the heat storage heat exchanger 4.

[0093] That is, the refrigerant compressed in the compressor 1 and discharged in a high-temperature, high-pressure state flows into the outdoor heat exchanger 3 via the first expansion valve 51 and the second switching valve 62, as shown by the arrow in Fig. 4. Note that at this time, the first expansion valve 51 is fully open. The refrigerant discharged from the compressor 1 also flows through the first switching valve 61, but also passes through the bypass circuit B1 and flows into the outdoor heat exchanger 3 from the second switching valve 62.

[0094] The refrigerant that has flowed into the outdoor heat exchanger 3 is cooled by the outdoor air that is supplied by the rotation of the outdoor fan 31, and dissipates heat into the outdoor air. Then, a part or all of the refrigerant is condensed.

[0095] The refrigerant that has thus released heat to the outside air flows out of the outdoor heat exchanger 3 and passes through the third expansion valve 53, where it is decompressed to become a low-temperature, low-pressure refrigerant. The low-temperature, low-pressure refrigerant then flows into the indoor heat exchanger 2, where it exchanges heat with the indoor air.

[0096] Through heat exchange by the indoor heat exchanger 2, the refrigerant absorbs heat from the indoor air and evaporates, and the indoor air drawn into the indoor heat exchanger 2 is cooled and supplied to the room by the indoor fan 21 to cool the room. Then, the refrigerant that has absorbed heat through heat exchange flows into the compressor 1 via the first switching valve 61.

[0097] On the other hand, the flow of the refrigerant when the refrigeration cycle apparatus S performs a heat-storage heating operation is as shown in Fig. 5. Fig. 5 is a refrigerant circuit diagram showing the flow of the refrigerant when the refrigeration cycle apparatus S according to the embodiment of the present invention performs a heat-storage heating operation.

[0098] As shown in Fig. 5, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 via the first switching valve 61. Then, in the indoor heat exchanger 2, heat is exchanged between the refrigerant and the air flowing into the indoor unit, and air that has absorbed heat from the refrigerant and been warmed is supplied to the indoor space. Therefore, the indoor heat exchanger 2 functions as a condenser.

[0099] The refrigerant flowing out of the indoor heat exchanger 2 flows into the outdoor heat exchanger 3 via the third expansion valve 53. The outdoor heat exchanger 3 functions as an evaporator, and heat is exchanged between the refrigerant and the outdoor air. The refrigerant flowing out of the outdoor heat exchanger 3 flows into the compressor 1 via the second switching valve 62.

[0100] As described above, the refrigeration cycle apparatus S in the embodiment of the present invention is provided with the heat storage heat exchanger 4 in addition to the indoor heat exchanger 2 and the outdoor heat exchanger 3. When the heat storage heating operation is performed, the refrigerant discharged from the compressor 1 not only flows into the indoor heat exchanger 2 as described above, but also branches before reaching the first switching valve 61 and flows into the heat storage heat exchanger 4 via the first expansion valve 51 and the second switching valve 62.

[0101] In the heat storage heat exchanger 4, the refrigerant exchanges heat with a heat storage material, so that heat of the refrigerant is stored in the heat storage material. The refrigerant flowing out of the heat storage heat exchanger 4 flows into the outdoor heat exchanger 3 via the second expansion valve 52, and further flows out of the outdoor heat exchanger 3 and flows into the compressor 1 via the second switching valve 62.

[0102] 6 is a refrigerant circuit diagram showing the flow of refrigerant when the refrigeration cycle apparatus S according to the embodiment of the present invention performs defrosting heating operation. The refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 via the first switching valve 61. Since the operation is heating here, the indoor heat exchanger 2 functions as a condenser, and exchanges heat between the refrigerant and the air flowing into the indoor unit in the indoor heat exchanger 2, and supplies the warmed air that has absorbed heat from the refrigerant to the indoor space.

[0103] In addition, the refrigerant discharged from the compressor 1 branches before reaching the first switching valve 61, and flows into the outdoor heat exchanger 3 via the first expansion valve 51 and the second switching valve 62. When the high-temperature refrigerant from the compressor 1 flows into the outdoor heat exchanger 3, a defrosting operation is performed to melt the frost adhering to the outdoor heat exchanger 3.

[0104] The refrigerant flowing out from the indoor heat exchanger 2 flows into the heat storage heat exchanger 4 via the third expansion valve 53 and the second expansion valve 52. At this time, the third expansion valve 53 and the second expansion valve 52 are fully open. The refrigerant flowing out from the outdoor heat exchanger 3 flows into the heat storage heat exchanger 4 via the second expansion valve 52. In the heat storage heat exchanger 4, heat exchange is performed between the flowing in refrigerant and the heat storage material. The refrigerant flowing out from the heat storage heat exchanger 4 flows into the compressor 1 via the second switching valve 62.

[0105] Next, a description will be given of the flow of the refrigerant when the refrigeration cycle apparatus S performs the heat storage heating operation. Fig. 7 is a refrigerant circuit diagram showing the flow of the refrigerant when the refrigeration cycle apparatus S according to the embodiment of the present invention performs the heat storage heating operation.

[0106] 7, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 via the first changeover valve 61. In the case of the heat storage heating operation, all of the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2. Therefore, the expansion valve 51 provided in the first circuit branching off before reaching the first changeover valve 61 is controlled by the changeover control unit 74 to be fully closed.

[0107] The refrigerant that has flowed into the indoor heat exchanger 2 exchanges heat with the air flowing into the indoor unit in the indoor heat exchanger 2, and air that has absorbed heat from the refrigerant and been warmed is supplied to the indoor space. Therefore, the indoor heat exchanger 2 functions as a condenser.

[0108] The refrigerant flowing out from the indoor heat exchanger 2 flows into the heat storage heat exchanger 4 via a junction C1 provided in a flow path between the second expansion valve 52 and the outdoor heat exchanger 3. The heat storage heat exchanger 4 functions as an evaporator, and in the heat storage heat exchanger 4, the low-temperature, low-pressure refrigerant that has flowed in exchanges heat with a heat storage material. The refrigerant flowing out from the heat storage heat exchanger 4 flows into the compressor 1 via the second switching valve 62.

[0109] The refrigerant flowing out of the indoor heat exchanger 2 flows into the outdoor heat exchanger 3 via the third expansion valve 53. The outdoor heat exchanger 3 functions as an evaporator, and heat is exchanged between the refrigerant and the outdoor air. The refrigerant flowing out of the outdoor heat exchanger 3 flows into the compressor 1 via the second changeover valve 62, the bypass circuit B2, and the first changeover valve 61.

[0110] In the case of the heat storage heating operation, as described above, the bypass circuit B2 employs an on-off valve instead of a check valve as in the conventional bypass circuit B1. This on-off valve allows the refrigerant flowing out of the outdoor heat exchanger 3 to flow from the second changeover valve 62 to the first changeover valve 61, and can be returned to the compressor 1.

[0111] Finally, a description will be given of the flow of the refrigerant when the refrigeration cycle apparatus S performs normal heating operation. Fig. 8 is a refrigerant circuit diagram showing the flow of the refrigerant when the refrigeration cycle apparatus S according to the embodiment of the present invention performs normal heating operation.

[0112] As shown in Fig. 8, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 via the first switching valve 61. Then, in the indoor heat exchanger 2, heat is exchanged between the refrigerant and the air flowing into the indoor unit, and air that has absorbed heat from the refrigerant and been warmed is supplied to the indoor space. Therefore, the indoor heat exchanger 2 functions as a condenser.

[0113] The refrigerant flowing out of the indoor heat exchanger 2 flows into the outdoor heat exchanger 3 via the third expansion valve 53. The outdoor heat exchanger 3 functions as an evaporator, and heat is exchanged between the refrigerant and the outdoor air. The refrigerant flowing out of the outdoor heat exchanger 3 flows into the compressor 1 via the second switching valve 62.

[0114] On the other hand, as described above, in normal heating operation, since there is no need to cause the refrigerant to flow into the heat storage heat exchanger 4, the first expansion valve 51 is controlled to be fully closed so that the refrigerant discharged from the compressor 1 does not flow into the heat storage heat exchanger 4. Therefore, no heat exchange takes place between the heat storage material and the refrigerant in the heat storage heat exchanger 4. In addition, the second expansion valve 52 is also controlled to be fully closed.

[0115] [Operation] Next, the flow of control of the refrigeration cycle apparatus S by the control device 7 when the operation mode is switched from the above-mentioned heat storage heating operation, heat storage utilization heating operation, or normal heating operation to the defrost heating operation will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a flowchart showing the flow of control when the operation mode is changed in the refrigeration cycle apparatus S according to the embodiment of the present invention.

[0116] As described above, there are various types of heating operation, but the following will be described taking an example in which the operation mode is switched from the heat-storage heating operation to the defrosting heating operation as before.

[0117] First, in the refrigeration cycle apparatus S, a heat storage heating operation is started (ST1). The conditions for starting the heat storage heating operation are set in advance, and the control device 7 judges whether or not the conditions are met. As a condition for starting the heat storage heating operation, for example, a condition that the difference between the heat storage material temperature and the outside air temperature is less than a predetermined value is set. This allows the heat storage heating operation to be executed when the amount of stored heat is insufficient.

[0118] When the heat storage heating operation is started, as described above, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 through the first switching valve 61, and also flows into the heat storage heat exchanger 4 through the first expansion valve 51 and the second switching valve 62.

[0119] While the heat storage heating operation is being performed, the control device 7 determines whether or not a defrosting operation is required for the outdoor heat exchanger 3 according to a preset condition for transitioning to the defrosting operation (ST2). If the defrosting operation is not required (NO in ST2), the heat storage heating operation continues.

[0120] On the other hand, if the control device 7 (judgment unit 71) judges that the conditions for starting the defrosting heating operation are met (YES in ST2), a switching process is executed to switch the operating mode from the heat storage heating operation to the defrosting heating operation (ST3).

[0121] Specifically, the determination unit 71 instructs the switching control unit 74 to switch the second switching valve 62. Based on the instruction, the switching control unit 74 switches the second switching valve 62 so that the refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 3 instead of the heat storage heat exchanger 4.

[0122] Then, the determination unit 71 sets the rotation speed of the indoor fan 21 after the operation mode has been switched (ST5). A detailed flow of the process using the calculation unit 73 for setting the rotation speed of the indoor fan 21 will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the flow of control when the operation mode has changed in the refrigeration cycle apparatus S according to the embodiment of the present invention.

[0123] The calculation unit 73, which has received an instruction from the determination unit 71 to switch the operation mode from the heat storage heating operation to the defrost heating operation, first accesses the memory unit 72 and calculates the sum of the internal volumes of the refrigerant flow paths of all heat exchangers that function as condensers in the heat storage heating operation (ST51). Since the condensers in the heat storage heating operation are the indoor heat exchanger 2 and the heat storage heat exchanger 4, the calculation unit 73 calculates the sum of the internal volumes of the refrigerant flow paths of each of these heat exchangers.

[0124] Next, the calculation unit 73 calculates the sum of the internal volumes of the refrigerant flow paths of all heat exchangers that function as condensers in the defrosting heating operation (ST52). Since the condensers in the defrosting heating operation are the indoor heat exchanger 2 and the outdoor heat exchanger 3, the calculation unit 73 calculates the sum of the internal volumes of the refrigerant flow paths of each of these heat exchangers.

[0125] The calculation unit 73 calculates a rate of change of the internal volume of the refrigerant flow path of the heat exchanger during the defrost heating operation after the switching (the internal volume of the condenser refrigerant flow path after the switching) relative to the internal volume of the refrigerant flow path of the heat exchanger during the heat-storage heating operation before the switching of the operation mode (the internal volume of the condenser refrigerant flow path before the switching) (ST53).Then, the calculation unit 73 uses the calculated rate of change to set the rotation speed of the indoor fan 21 after the operation mode is switched to the defrost heating operation based on a value multiplied by the rotation speed of the indoor fan 21 during the operation mode before the switching of the operation mode (here, the defrost heating operation) (ST54).

[0126] The determination unit 71 sets the rotation speed of the indoor fan 21 calculated by the calculation unit 73 as the rotation speed of the indoor fan 21 in the operation mode after switching. Then, the determination unit 71 instructs the indoor unit via the switching control unit 74 to drive the indoor fan 21 based on the set rotation speed of the indoor fan 21.

[0127] Note that, instead of using the above method for setting the rotation speed of the indoor fan 21, a method may also be adopted in which, when starting defrost heating operation, the determination unit 71 acquires information regarding the internal volume of the refrigerant flow path from the memory unit 72 based on the type of heating operation that was performed before the defrost heating operation, and sets the rotation speed of the indoor fan 21.

[0128] Then, when the process of switching the operation mode to the defrosting heating operation is completed, the defrosting heating operation is started (ST6 in FIG. 9). As described above, in the defrosting heating operation, the heating operation is performed and the defrosting operation is performed using the heat stored in the heat storage heat exchanger 4.

[0129] While the defrosting heating operation is being performed, the control device 7 determines whether or not to end the defrosting heating operation based on a preset end condition (ST7).

[0130] When the control device 7 judges not to end the defrosting heating operation (NO in ST7), the defrosting heating operation being executed is continued. On the other hand, when the control device 7 judges that the defrosting heating operation is to be ended (YES in ST7), the defrosting heating operation is ended (ST8).

[0131] Since the defrosting heating operation has ended, the control device 7 executes the operation mode switching process again (ST9). The operation mode to be switched from the defrosting heating operation is not specified here, but the operation mode may be the heat storage heating operation again. Alternatively, the operation mode may be switched to the heat storage heating operation or the normal heating operation based on the user's settings, etc.

[0132] The control device 7 controls the switching valve 6 via the switching control section 74 (ST10), and sets the rotation speed of the indoor fan 21 according to the mode of the heating operation (ST11).

[0133] That is, so far, we have explained the case where the internal volume of the refrigerant flow path of the condenser increases as the operation mode changes and the heat exchanger that plays the role of the condenser changes. In this case, as described above, the rotation speed of the indoor fan 21 is controlled to be reduced. On the other hand, when the operation mode changes and the heat exchanger that plays the role of the condenser changes, the internal volume of the refrigerant flow path of the condenser decreases and the condensing temperature rises, the rotation speed of the indoor fan 21 is controlled to be increased.

[0134] Such control is performed, for example, when the operation mode is switched from the defrost heating operation to the heat storage heating operation. Therefore, in the operation of the refrigeration cycle apparatus S described above, in the switching process when the defrost heating operation is switched to the heating operation, the rotation speed of the indoor fan 21 is set to be increased.

[0135] In the explanation here, the control of the switching valve 6 and the setting of the rotation speed of the indoor fan 21 are explained first and then the latter. However, this order is merely for the convenience of explanation, and the order of the control of the switching valve 6 and the setting of the rotation speed of the indoor fan 21 may be reversed, or both may be performed simultaneously.

[0136] As described above, when the operation mode is switched from the heating operation to the defrost heating operation, the rotation speed of the indoor fan 21 is controlled in accordance with the drop in the condensation temperature, thereby preventing a sudden drop or rise in the temporary blown temperature from the indoor unit. Therefore, even if the operation mode is switched, a decrease in comfort for the user can be suppressed.

[0137] In particular, when cool air is supplied to the room due to a drop in condensation temperature, the decrease in comfort for the user becomes significant. Therefore, in such a case, it is very effective to control the rotation speed of the indoor fan 21 to be reduced based on the internal volume of the refrigerant flow path of the heat exchanger that serves as a condenser.

[0138] It should be noted that the present invention is not limited to the above-described embodiment, but is merely an example of the present invention. In the implementation stage, the components can be modified without departing from the gist of the invention, and various modifications and improvements can be made to the above-described embodiment. In addition, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiment.

[0139] For example, some of the components shown in the embodiment may be deleted. Furthermore, components from different embodiments may be appropriately combined, and such modified or improved forms may also be included in the present invention. Such embodiments and modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0140] For example, in the processing flow for switching the operating mode described above, when the judgment unit 71 judges that the conditions for starting the defrost heating operation are satisfied, it switches the switching valve 6 and sets the rotation speed of the indoor fan 21, and instructs the indoor unit to rotate the indoor fan 21 at the set rotation speed of the indoor fan 21.

[0141] However, instead of this processing, for example, when the judgment unit 71 judges that the conditions for starting the defrost heating operation are satisfied, the judgment unit 71 first sets the rotation speed of the indoor fan 21 and instructs the indoor unit of the set rotation speed.

[0142] In this case, following this process, the switching valve 6 is controlled, but before this control of the switching valve 6 is executed, the rotation speed of the indoor fan 21 is gradually reduced. Then, when the switching valve 6 is actually switched and the defrost heating operation is started, the rotation speed of the indoor fan 21 has already been reduced to the set rotation speed.

[0143] By performing such processing, the timing of switching the operation mode and the timing of the processing for changing the rotation speed of the indoor fan 21 can be more closely matched, which contributes to maintaining even greater comfort for the user.

[0144] Also, so far, it has been described that the calculation unit 73 calculates the rate of change of the internal volume of the condenser refrigerant flow path after switching to the internal volume of the condenser refrigerant flow path before switching the operation mode when setting the rotation speed of the indoor fan 21. However, when the calculation unit 73 calculates the rate of change, for example, the set temperature in the indoor unit before switching the operation mode and the current room temperature after switching may be used.

[0145] Furthermore, in the refrigeration cycle apparatus S according to the embodiment of the present invention, various explanations have been given on the assumption that the refrigeration cycle apparatus S includes a refrigerant circuit C in which the indoor heat exchanger 2, the outdoor heat exchanger 3, and the heat storage heat exchanger 4 are connected in parallel. However, the above explanations also apply to the case of a refrigeration cycle apparatus including a refrigerant circuit in which these heat exchangers are connected in series.

[0146] In the above description of the heat storage heating operation, the case where the outdoor heat exchanger functions as an evaporator in addition to the heat storage heat exchanger has been described as an example. However, in the heat storage heating operation, it is also possible to have only the heat storage heat exchanger function as an evaporator without necessarily having the outdoor heat exchanger function as an evaporator.

[0147] The techniques described in the embodiments of the present invention may also be configured as follows. (1) a compressor that compresses a refrigerant; an indoor heat exchanger that exchanges heat between indoor air and the refrigerant; an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant; a heat storage heat exchanger that exchanges heat between a heat storage material and the refrigerant; a refrigerant circuit including a plurality of switching valves for switching a circulation path of the refrigerant between a heating operation in which at least the indoor heat exchanger functions as a condenser and the outdoor heat exchanger functions as an evaporator and a defrosting operation in which at least the outdoor heat exchanger functions as a condenser; an indoor fan that passes the indoor air through the indoor heat exchanger; A control device that controls the indoor fan and the switching valve, The refrigeration cycle apparatus, wherein the control device changes a rotation speed of the indoor fan when switching between the heating operation and the defrosting operation. (2) The control device A storage unit is provided that stores information regarding the internal volumes of the refrigerant flow paths of at least the indoor heat exchanger, the outdoor heat exchanger, and the heat storage heat exchanger, The refrigeration cycle device described in (1) above, characterized in that when the control device controls the change in the rotation speed of the indoor fan, the rotation speed of the indoor fan is set based on information regarding the internal volume of the refrigerant flow path. (3) The control device further comprises: A calculation unit that calculates a sum of the internal volumes of all condenser refrigerant flow paths of the heat exchanger that functions as a condenser in each operating mode based on information about the internal volumes of the refrigerant flow paths stored in the memory unit, The calculation unit calculates a rate of change in an internal volume of the post-switching condenser refrigerant flow path after switching to an internal volume of the pre-switching condenser refrigerant flow path before switching the operation mode, The refrigeration cycle device described in (2) above, characterized in that when the control device controls the change in the rotation speed of the indoor fan, the control device sets the rotation speed of the indoor fan after the operation mode is switched based on the change rate. (4) The control device of any one of (1) to (3) above is characterized in that, by switching the switching valve, the control device controls to reduce the rotation speed of the indoor fan when switching from a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as condensers and the outdoor heat exchanger function as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger function as an evaporator. (5) The control device is characterized in that, by switching the switching valve, the control device controls the indoor fan to reduce its rotation speed when switching from a heat storage heating operation in which the indoor heat exchanger functions as a condenser and the outdoor heat exchanger and the heat storage heat exchanger function as evaporators to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger function as an evaporator. (6) The refrigeration cycle device described in any one of (1) to (3) above, characterized in that the control device controls the indoor fan to reduce its rotation speed when switching from a normal heating operation in which the indoor heat exchanger functions as a condenser and only the outdoor heat exchanger functions as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator by switching the switching valve. (7) The refrigeration cycle device according to any one of (1) to (6) above, wherein an internal volume of the refrigerant passage of the heat storage heat exchanger is smaller than an internal volume of the refrigerant passage of the outdoor heat exchanger. (8) A refrigerant circuit that circulates a refrigerant A compressor that compresses the refrigerant; an indoor heat exchanger that exchanges heat between indoor air and the refrigerant; an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant; a heat storage heat exchanger that exchanges heat between a heat storage material and the refrigerant; a plurality of switching valves that switch a circulation path of the refrigerant in the refrigerant circuit between a heating operation in which at least the indoor heat exchanger functions as a condenser and a defrosting operation in which at least the outdoor heat exchanger functions as a condenser are connected; an indoor fan that passes the indoor air through the indoor heat exchanger; A control device that controls the indoor fan and the switching valve, The control device includes: A step of determining whether to switch an operation mode between the heating operation and the defrosting operation; When it is determined that the operation mode is to be switched, switching the switching valve; performing control to change the rotation speed of the indoor fan in accordance with the operation mode after switching the rotation speed of the indoor fan; A control method for a refrigeration cycle device comprising: (9) In the step of the control device performing control to change the rotation speed of the indoor fan, The control method for a refrigeration cycle apparatus described in (8) above, characterized in that the rotation speed of the indoor fan is set based on information regarding the internal volume of each refrigerant flow path of at least the indoor heat exchanger, the outdoor heat exchanger, and the heat storage heat exchanger. (10) In a step before the step in which the control device performs control to change the rotation speed of the indoor fan, Calculating the sum of the internal volumes of all condenser refrigerant flow paths of the heat exchanger functioning as a condenser in each operating mode based on the information about the internal volumes of the refrigerant flow paths; Calculating a rate of change in an internal volume of a post-switching condenser refrigerant flow path after switching to an internal volume of a pre-switching condenser refrigerant flow path before switching of the operation mode; setting a rotation speed of the indoor fan after the operation mode is switched based on the rate of change; The control method for a refrigeration cycle apparatus according to (9) above, (11) The step of the control device performing control to change the rotation speed of the indoor fan includes: The control method for a refrigeration cycle apparatus described in any one of (8) to (10) above, characterized in that the control device switches the switching valve to switch from a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as condensers and the outdoor heat exchanger function as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator, thereby performing control to reduce the rotation speed of the indoor fan. (12) The step of the control device performing control to change the rotation speed of the indoor fan includes: The control method for a refrigeration cycle apparatus according to any one of (8) to (10), characterized in that the control device switches the switching valve to switch from a heat storage heating operation in which the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger and the heat storage heat exchanger function as an evaporator, to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers, and the heat storage heat exchanger functions as an evaporator, performing control to reduce the rotation speed of the indoor fan. (13) The step of the control device performing control to change the rotation speed of the indoor fan includes: The control method for a refrigeration cycle apparatus described in (8) above, characterized in that the control device performs control to reduce the rotation speed of the indoor fan when switching from normal heating operation, in which the indoor heat exchanger functions as a condenser and only the outdoor heat exchanger functions as an evaporator, to defrost heating operation, in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator, by switching the switching valve. [Explanation of symbols]

[0148] REFERENCE SIGNS LIST 1 compressor, 2 indoor heat exchanger, 3 outdoor heat exchanger, 31 outdoor fan, 4 heat storage heat exchanger, 5 expansion valve, 51 first expansion valve, 52 second expansion valve, 53 third expansion valve, 6 changeover valve, 61 first changeover valve, 62 second changeover valve, 7 control device, 71 determination unit, 72 storage unit, 73 calculation unit, 74 changeover control unit, C refrigerant circuit, S refrigeration cycle device

Claims

1. A compressor that compresses a refrigerant; an indoor heat exchanger that exchanges heat between indoor air and the refrigerant; an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant; a heat storage heat exchanger that exchanges heat between a heat storage material and the refrigerant; a refrigerant circuit including a plurality of switching valves for switching a circulation path of the refrigerant between a heating operation in which at least only the indoor heat exchanger functions as a condenser and a defrosting operation in which at least the outdoor heat exchanger functions as a condenser; an indoor fan that passes the indoor air through the indoor heat exchanger; A storage unit that stores information regarding an internal volume of each of the refrigerant flow paths of the indoor heat exchanger and the outdoor heat exchanger; A control device that controls the indoor fan and the switching valve, The refrigeration cycle device, wherein the control device changes the rotation speed of the indoor fan based on information regarding an internal volume of the refrigerant flow path when switching between the heating operation and the defrosting operation.

2. The control device further comprises: A calculation unit that calculates a sum of the internal volumes of all condenser refrigerant flow paths of the heat exchanger that functions as a condenser in each operating mode based on information about the internal volumes of the refrigerant flow paths stored in the memory unit, The calculation unit calculates a rate of change in an internal volume of the post-switching condenser refrigerant flow path after switching to an internal volume of the pre-switching condenser refrigerant flow path before switching the operation mode, 2. The refrigeration cycle apparatus according to claim 1, wherein when the control device performs control to change the rotation speed of the indoor fan, the control device sets the rotation speed of the indoor fan after the operation mode is switched based on the rate of change.

3. The refrigeration cycle apparatus according to claim 1, characterized in that the control device performs control to reduce the rotation speed of the indoor fan when switching from a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as condensers and the outdoor heat exchanger function as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger function as an evaporator by switching the switching valve.

4. The refrigeration cycle apparatus according to claim 1, characterized in that the control device performs control to reduce the rotation speed of the indoor fan when switching from a heat storage heating operation in which the indoor heat exchanger functions as a condenser and the heat storage heat exchanger functions as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator by switching the switching valve.

5. 2. The refrigeration cycle apparatus according to claim 1, wherein the control device performs control to reduce the rotation speed of the indoor fan when switching from a normal heating operation in which the indoor heat exchanger functions as a condenser and only the outdoor heat exchanger functions as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator by switching the switching valve.

6. 6. The refrigeration cycle apparatus according to claim 1, wherein an internal volume of the refrigerant passage of the heat storage heat exchanger is smaller than an internal volume of the refrigerant passage of the exterior heat exchanger.

7. The refrigerant circuit that circulates the refrigerant A compressor that compresses the refrigerant; an indoor heat exchanger that exchanges heat between indoor air and the refrigerant; an outdoor heat exchanger that exchanges heat between outdoor air and the refrigerant; a heat storage heat exchanger that exchanges heat between a heat storage material and the refrigerant; a plurality of switching valves that switch a circulation path of the refrigerant in the refrigerant circuit between a heating operation in which at least only the indoor heat exchanger functions as a condenser and a defrosting operation in which at least the outdoor heat exchanger functions as a condenser are connected; an indoor fan that passes the indoor air through the indoor heat exchanger; A control device that controls the indoor fan and the switching valve, The control device includes: A step of determining whether to switch an operation mode between the heating operation and the defrosting operation; When it is determined that the operation mode is to be switched, switching the switching valve; performing control to change the rotation speed of the indoor fan in accordance with the operation mode after switching the rotation speed of the indoor fan; In the step of the control device performing control to change the rotation speed of the indoor fan, A method for controlling a refrigeration cycle apparatus, comprising: setting a rotation speed of the indoor fan based on information relating to an internal volume of a refrigerant flow path of each of the indoor heat exchanger and the outdoor heat exchanger.

8. In a step before the step in which the control device performs control to change the rotation speed of the indoor fan, Calculating the sum of the internal volumes of all condenser refrigerant flow paths of the heat exchanger functioning as a condenser in each operating mode based on the information about the internal volumes of the refrigerant flow paths; Calculating a rate of change in an internal volume of a post-switching condenser refrigerant flow path after switching to an internal volume of a pre-switching condenser refrigerant flow path before switching of the operation mode; setting a rotation speed of the indoor fan after the operation mode is switched based on the rate of change; The method for controlling a refrigeration cycle apparatus according to claim 7, further comprising:

9. The step of the control device performing control to change the rotation speed of the indoor fan includes: The control method for a refrigeration cycle apparatus according to claim 7, characterized in that the control device switches the switching valve to switch from a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as condensers and the outdoor heat exchanger function as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger function as an evaporator, thereby performing control to reduce the rotation speed of the indoor fan.

10. The step of the control device performing control to change the rotation speed of the indoor fan includes: The control method for a refrigeration cycle device according to claim 7, characterized in that the control device switches the switching valve to switch from a heat storage heating operation in which the indoor heat exchanger functions as a condenser and the heat storage heat exchanger functions as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator, thereby performing control to reduce the rotation speed of the indoor fan.

11. The step of the control device performing control to change the rotation speed of the indoor fan includes: The control method for a refrigeration cycle device according to claim 7, characterized in that the control device performs control to reduce the rotation speed of the indoor fan when switching from a normal heating operation in which the indoor heat exchanger functions as a condenser and only the outdoor heat exchanger functions as an evaporator to a defrost heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as condensers and the heat storage heat exchanger functions as an evaporator by switching the switching valve.

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