Refrigeration cycle device and control method for refrigeration cycle device

Abstract

To provide a refrigeration cycle device and a control method for the refrigeration cycle device capable of suppressing deterioration of comfort of a user even when an operating form is switched.SOLUTION: A compressor 1 that compresses a refrigerant, an indoor heat exchanger 2 that exchanges heat between indoor air and the refrigerant, an indoor fan 21 that causes the indoor air to pass through the indoor heat exchanger 2, an outdoor heat exchanger 3 that exchanges heat between outdoor air and the refrigerant, a thermal storage heat exchanger 4 that exchanges heat between a thermal storage medium and the refrigerant and a plurality of selector valves 6 for switching a circulation passage of the refrigerant in a refrigerant circuit C between heating operation for causing at least the indoor heat exchanger 2 to function as a condenser and defrosting operation for causing at least the outdoor heat exchanger 3 to function as a condenser are connected to the refrigerant circuit C for circulating the refrigerant. A refrigeration cycle device includes a control device 7 that controls the indoor fan 21 and the selector valves 6. The control device 7 switches operation between the heating operation and the defrosting operation, and changes the rotational frequency of the indoor fan.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a refrigeration cycle apparatus and a control method for a refrigeration cycle apparatus.

Background Art

[0002] Generally, when a heating operation is performed in an air conditioner, a low-temperature refrigerant flows through an outdoor heat exchanger. Therefore, for example, when the outside air temperature is below freezing, if the temperature of the refrigerant drops below the dew point temperature of the outside air, frost adheres to the outdoor heat exchanger, making heat exchange with the outside air difficult. Therefore, when the heating operation is being performed, a defrosting operation for periodically removing frost from the outdoor heat exchanger is performed.

[0003] Such a defrosting operation is a necessary operation for operating the air conditioner. 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 case of such a 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, during the defrosting operation, the heating operation stops and the indoor temperature gradually decreases, so the comfort of the user decreases. Therefore, for example, as shown in Patent Document 1 below, 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 operation mode is appropriately referred to as "heat storage heating operation").

[0005] Then, during the defrosting operation, a method of continuing the heating operation even during the defrosting operation by using the heat stored in the heat storage device can be considered (hereinafter, such an operation mode will be appropriately referred to as "defrosting heating operation"). By this method, it is possible to prevent a decrease in the indoor temperature due to a temporary stop of the heating operation for the defrosting operation and to maintain the comfort of the user.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In an air conditioner equipped with such a heat storage device, for example, when shifting from the heat storage heating operation to the defrosting heating operation, the heat exchanger that serves as the condenser is partially changed. That is, in the case of the heat storage heating operation, the indoor heat exchanger and the heat exchanger of the heat storage device are condensers, and the outdoor heat exchanger serves as an evaporator. On the other hand, in the case of the defrosting heating operation, the indoor heat exchanger and the outdoor heat exchanger are condensers, and the heat exchanger of the heat storage device serves as an evaporator.

[0008] Therefore, when shifting from the heat storage heating operation to the defrosting heat storage operation, the internal volume of the refrigerant flow path of the heat exchanger that serves as the condenser will increase. 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 flow path of the heat exchanger when the operation mode is changed in the refrigeration cycle device.

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

[0010] Also, in any of the graphs, on the vertical axis, the "heat exchanger serving as a condenser" in each case is shown in the upper part, and the "heat exchanger serving as an evaporator" is shown in the lower part. On the other hand, on the horizontal axis, the "inner volume of the refrigerant flow path" is shown.

[0011] Furthermore, in each of the graphs, the inner volumes of the refrigerant flow paths of three types of heat exchangers, namely, the "indoor heat exchanger", the "outdoor heat exchanger", and the "heat exchanger of the heat storage device (represented as the 'heat storage heat exchanger' in FIG. 11)", which constitute the air conditioner, are shown.

[0012] As described above, since the horizontal axis of the graph indicates the inner volume of the refrigerant flow path, the inner volumes of the refrigerant flow paths of each heat exchanger are shown so as to extend from the left side to the right side in the graph. For example, on the upper side of FIG. 11, the inner volumes of the refrigerant flow paths of each heat exchanger during the heat storage heating operation are shown. During the heat storage heating operation, the "indoor heat exchanger" and the "heat storage heat exchanger" serve as the condenser. On the other hand, the "outdoor heat exchanger" serves as the evaporator.

[0013] Therefore, in the graph shown on the upper side of FIG. 11, in the portion of the "heat exchanger serving as a condenser", the inner volumes of the refrigerant flow paths of the "indoor heat exchanger" and the "heat storage heat exchanger" are shown. In contrast, in the portion of the "heat exchanger serving as an evaporator", the inner volume of the refrigerant flow path of the "outdoor heat exchanger" is shown.

[0014] Looking at the graph shown on the upper side of FIG. 11, it can be seen that the inner volume of the refrigerant flow path of the heat exchanger serving as a condenser is the sum of the inner volume of the refrigerant flow path of the indoor heat exchanger and the inner volume of the refrigerant flow path of the heat storage heat exchanger. On the other hand, since the heat exchanger serving as an evaporator is only the outdoor heat exchanger, the inner volume of the refrigerant flow path of the heat exchanger serving as an evaporator is equal to the inner volume of the refrigerant flow path of the outdoor heat exchanger.

[0015] When comparing the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser with the internal volume of the refrigerant flow path of the heat exchanger serving as the evaporator, it can be seen that the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser is larger than that of the heat exchanger serving as the evaporator. In such a state, when the air conditioner shifts from the heat storage heating operation to the defrosting heating operation, since the heat exchanger serving as the condenser changes during the heat storage heating operation, changes will occur in the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser and the internal volume of the refrigerant flow path of the heat exchanger serving as the evaporator.

[0016] The lower graph in Fig. 11 is a graph showing the internal volume of the refrigerant flow path of each heat exchanger during the defrosting heating operation as described above. When the defrosting heating operation is performed, the heat exchangers serving as the condenser are the indoor heat exchanger and the outdoor heat exchanger. On the other hand, the heat exchanger serving as the evaporator is only the heat storage heat exchanger. Looking at the internal volume of the refrigerant flow path in each case, it can be seen that the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser is much larger than that of the heat exchanger serving as the evaporator.

[0017] When comparing the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser during the heat storage heating operation with the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser during the defrosting heating operation, it can be seen that the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser in the latter is larger than that in the former by the amount of arrow A.

[0018] Thus, for example, as shown in Fig. 11, by shifting from the heat storage heating operation to the defrosting heating operation, the internal volume of the refrigerant flow path of the heat exchanger serving as the condenser will increase rapidly. When the internal volume of the refrigerant flow path increases due to the change in the operating mode in this way, the amount of the high-density liquid-phase refrigerant in the condenser increases, so the pressure of the refrigerant flowing through the inside of the refrigerant circuit decreases as the volume of the refrigerant decreases. And when the pressure of the refrigerant decreases, the condensation temperature in the condenser also drops.

[0019] This will be described with reference to FIG. 12. FIG. 12 is a graph showing the relationship between the rotational speed of the indoor fan and the condensation temperature when the indoor fan is controlled when the operating mode is changed in a conventional refrigeration cycle apparatus.

[0020] In FIG. 12, the horizontal axis represents time, and the operating mode is switched at a certain time on the horizontal axis. Here, the operating mode before the switch is the heat storage heating operation, and the operating mode after the switch is the defrosting heating operation. Also, among the lines extending from the left side to the right side of the graph along with the passage of time, the upper solid line indicates the rotational speed (air volume) of the indoor fan provided in the indoor unit. On the other hand, the lower broken line indicates the condensation temperature.

[0021] When the operating mode is switched from the heat storage heating operation to the defrosting heating operation, as shown in FIG. 11, the internal volume of the refrigerant flow path of the heat exchanger that serves as the condenser increases. Therefore, the pressure of the refrigerant flowing in the refrigerant circuit decreases, and the condensation temperature also decreases. The fact that the condensation temperature indicated by the broken line in FIG. 12 decreases at the boundary of the switching of the operating mode shows this.

[0022] On the other hand, in order to control the rotational speed of the indoor fan based on the set information input via a remote control or the like, or the suction temperature, the rotational speed of the indoor fan does not change immediately even when the operating mode is switched from the heat storage heating operation to the defrosting heating operation. Specifically, since the rotational speed of the indoor fan does not decrease until the condensation temperature becomes equal to or lower than a predetermined value of the condensation temperature at which a cold air feeling is felt, the rotational speed of the indoor fan does not follow the decrease in the condensation temperature. Therefore, for a while, the indoor fan will rotate at the rotational speed during the heat storage heating operation, and cold air will be provided indoors.

[0023] Whether it is the heat storage heating operation or the defrosting heating operation, the indoor heat exchanger still serves as the condenser. In this way, when the operating mode is switched and the condensation temperature drops, cold air will be supplied to the heated indoor space. Such supply of cold air indoors may reduce the comfort of the user, especially during the heating operation.

[0024] The present invention has been made in view of the above-described problems, and an object thereof is to provide a refrigeration cycle device and a control method for the refrigeration cycle device that can suppress a decrease in comfort for a user even when the operation mode is switched.

Means for Solving the Problems

[0025] A refrigeration cycle device according to an aspect of the present invention includes a compressor that compresses a refrigerant, an indoor heat exchanger that exchanges heat between indoor air and the refrigerant, an indoor fan that passes 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 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, and a control device that controls the indoor fan and the switching valves, and the control device switches the operation between the heating operation and the defrosting operation and changes the rotation speed of the indoor fan.

[0026] A control method for a refrigeration cycle device according to an aspect of the present invention includes a compressor that compresses a refrigerant, an indoor heat exchanger that exchanges heat between indoor air and the refrigerant, an indoor fan that passes 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 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, and a control device that controls the indoor fan and the switching valves, and the control device includes a step of determining whether to switch the operation mode between the heating operation and the defrosting operation, a step of switching the switching valves when it is determined to switch the operation mode, and a step of performing control to change the rotation speed of the indoor fan according to the operation mode after the switching.

Effects of the Invention

[0027] According to the present invention, even when the operation mode is switched, it is possible to suppress a decrease in comfort for the user.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0029] The structure of the refrigeration cycle device 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 device S according to an embodiment of the present invention. The refrigeration cycle device S includes a compressor 1, an indoor heat exchanger 2, an outdoor heat exchanger 3, a heat storage heat exchanger 4, expansion valves 5 (51, 52, 53), switching valves 6 (61, 62), and is provided with a refrigerant circuit C for circulating refrigerant. Further, it includes a control device 7 for controlling the expansion valve 5 and the switching valve 6.

[0030] Here, the refrigerant circuit C of the refrigeration cycle device 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 connecting these devices flows. For example, when the refrigeration cycle device S performs a normal heating operation described later, the refrigerant discharged from the compressor 1 flows in the order of the indoor heat exchanger 2 and the outdoor heat exchanger 3, and then is 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] Also, a first expansion valve 51 and a second switching valve 62 are provided in order in the flow path connecting the compressor 1 and the heat storage heat exchanger 4 during the heat storage heating operation. A second expansion valve 52 is provided in the flow path connecting the heat storage heat exchanger 4 and the confluence point 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 respectively. The refrigerant flowing out of the heat storage heat exchanger 4 flows through the second expansion valve 52 and the confluence point C1 provided in the flow path between the second expansion valve 52 and the outdoor heat exchanger 3 to the outdoor heat exchanger 3, and then is sucked into the compressor 1.

[0032] The first switching valve 61 is controlled by a control device 7 described later, and switches between a case where the refrigerant discharged from the compressor 1 flows to the indoor heat exchanger 2 and a case where the refrigerant flows 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 or the like so that the refrigerant flows only in the direction of the arrow as shown in FIG. 1.

[0033] Note that the bypass circuit B1 in the refrigerant circuit C shown in FIG. 1 is provided with a check valve as described above so that the refrigerant flows only in the direction of the arrow. However, it is also possible not to provide the check valve in the bypass circuit B1 and to use an on-off valve such as a solenoid valve. By adopting such an on-off valve, it becomes possible to flow the refrigerant from the second switching valve 62 toward the first switching valve 61, such as in the heat storage utilization heating operation described later.

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

[0035] The second switching valve 62 is controlled by the control device 7 and switches between a case where the refrigerant discharged from the compressor 1 flows to the heat storage heat exchanger 4 and a case where the refrigerant flows 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 in 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. Regarding the types of each of the compressor 1, the indoor heat exchanger 2, and the outdoor heat exchanger 3, the description is omitted here, but various types of devices can be adopted.

[0037] Note that the indoor heat exchanger 2 in the embodiment of the present invention is provided with an indoor fan 21 that allows indoor air to pass through the indoor heat exchanger 2. Further, the outdoor heat exchanger 3 is provided with an outdoor fan 31 that allows outside air to pass through the outdoor heat exchanger 3.

[0038] The heat storage heat exchanger 4 is a heat exchanger in which a heat storage material and the refrigerant passing through the heat storage heat exchanger 4 exchange heat. The heat storage heat exchanger 4 is, for example, a fin-and-tube type heat exchanger. And this heat storage heat exchanger 4 is arranged in a heat storage container filled with a heat storage material inside.

[0039] As the heat storage material, for example, regardless of whether it is a liquid or a solid, it suffices if 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 a liquid, the heat storage heat exchanger 4 will be immersed in the heat storage material filled in the heat storage container. That is, the periphery of the heat storage heat exchanger 4 is covered with 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, in a defrost heating operation or a heat storage utilization heating operation as described later.

[0040] Note that the volume of the heat transfer tube (from the inlet to the outlet) through which the refrigerant flows in the heat exchanger is referred to as the "inner volume of the refrigerant flow path", but the inner volume of the refrigerant flow path of the heat storage heat exchanger 4 is smaller than the inner 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, in the object where heat exchange with the refrigerant occurs, the heat storage material has a larger specific heat than air. Also, the heat exchange amount is proportional to the temperature difference, such that a larger temperature difference results in a greater heat exchange amount. Therefore, since the heat storage heat exchanger 4, where it is easier to secure a 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] A plurality of expansion valves 5 are provided in the refrigeration cycle device S in the embodiment of the present invention. Specifically, three expansion valves are provided. The first expansion valve 51 is provided on the upstream side in the direction in which the refrigerant flows when the heat storage heat exchanger 4 functions as a condenser.

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

[0044] The switching valve 6 is composed of the first switching valve 61 and the second switching valve 62 as described above. The first switching valve 61 is provided between the compressor 1 and the indoor heat exchanger 2. Also, 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] Also, the first switching valve 61 switches between the case of flowing the refrigerant to the indoor heat exchanger 2 and the case of flowing it to the bypass circuit B1. On the other hand, the second switching valve 62 switches between the case of flowing the refrigerant to the heat storage heat exchanger 4 and the case of flowing it to the outdoor heat exchanger 3.

[0046] In the following, when collectively explaining these three expansion valves 51, 52, and 53, they are referred to as "expansion valve 5", and when explaining each individual expansion valve, they are referred to by their respective names. Also, regarding the switching valve 6, when collectively explaining these two switching valves 61 and 62, it is referred to as "switching valve 6", and when explaining each individual switching valve, it is referred to by its respective name.

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

[0048] The control device 7 controls the opening degrees of the plurality of expansion valves 5. And by the control device 7 controlling the opening degrees of the respective expansion valves, the flow rate of the refrigerant flowing through the refrigerant circuit C can be adjusted. Also, as described above, the plurality of switching valves 6 are switched to switch the flow of the refrigerant circulating through the refrigerant circuit C.

[0049] By thus controlling the plurality of expansion valves 5 and the plurality of switching valves 6, the control device 7 performs, for example, a heating and heat storage operation in which the heating operation and the heat storage operation are performed in parallel. Also, for example, the control device 7 also performs control of the defrosting operation for the outdoor heat exchanger 3 that is performed in parallel with the heating operation.

[0050] Also, for example, when the operation is switched from the heat storage heating operation to the defrosting heating operation, while performing the control of the plurality of expansion valves 5 and switching valves 6 described above, the control device 7 performs control to change the rotational speed of the indoor fan 21.

[0051] Next, the control content by the control device 7 will be described in more detail. As described above, for example, when the operation mode switches from the heat storage heating operation to the defrosting heating operation, the internal volume of the refrigerant flow path of the heat exchanger that serves as the 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 the condensation temperature predetermined value at which a cold air feeling is felt.

[0052] In this way, since the rotation speed of the indoor fan 21 is not changed in accordance with the decreased condensation temperature, the rotation speed of the indoor fan does not follow the decrease in the condensation temperature. Therefore, even when the operation mode switches from the heat storage heating operation to the defrosting heating operation, the indoor fan continues to rotate at the rotation speed during the heat storage heating operation for some time, and a state where cold air is supplied into the room continues.

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

[0054] FIG. 2 is a block diagram showing the internal configuration of the control device 7 in the refrigeration cycle device S according to the 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 to perform the switching when switching various operation modes such as the cooling operation, the heat storage heating operation, and the defrosting heating operation. Further, for example, when the operation mode is switched from the heat storage heating operation to the defrosting heating operation, the rotation speed of the indoor fan 21 is controlled.

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

[0057] Based on the information regarding the internal volumes of the refrigerant flow paths stored in the storage unit 72 as described above, the calculation unit 73 calculates the sum of the internal volumes of all the condenser refrigerant flow paths of the heat exchanger that functions as a condenser in each operation mode. Note that the sum of the internal volumes of the condenser refrigerant flow paths may be stored in the storage unit 72 in advance. When the operation mode is switched, the switching control unit 74 executes the control of the opening degree of the expansion valve 5 and the switching valve 6 based on an instruction from the determination unit 71. Further, the rotation speed of the indoor fan 21 is also switched in accordance with the switching of the operation mode.

[0058] Next, the functions 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 defrost heating operation, the previous operation mode can be, as will be described later, the heat storage heating operation, the heat storage utilization heating operation, or each heating operation such as the normal heating operation. Therefore, here, the case where the operation mode is switched from the heat storage heating operation to the defrost heating operation will be taken as an example and described below.

[0059] When the refrigeration cycle device S is executing the heat storage heating operation, the determination unit 71 determines whether to switch the operation state from the heat storage heating operation to the defrost heating operation. That is, for example, when the heat storage heating operation is being performed, it determines whether the conditions for starting the defrost heating operation, which is determined to be necessary for the defrost heating operation, are satisfied.

[0060] Here, as a condition for starting the defrosting heating operation, for example, the evaporation temperature of the refrigerant in the outdoor heat exchanger 3 can be cited. That is, when the evaporation temperature is equal to or lower than a preset temperature, there is a possibility of frosting 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 of the defrosting heating operation is satisfied, an instruction to switch the switching valve 6 is issued to the switching control unit 74. That is, in order 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, the second switching valve 62 is switched.

[0062] Also, in addition, 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 defrosting heating operation in order to perform control to change the rotation speed of the indoor fan 21.

[0063] As described with reference to FIG. 11, when the operation mode is switched from the heat storage heating operation to the defrosting 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 remains as the condenser), so the amount of high-density liquid-phase refrigerant in the condenser increases. Therefore, as the volume of the refrigerant decreases, the pressure of the refrigerant flowing inside the refrigerant circuit decreases. When the pressure of the refrigerant decreases, the condensation temperature in the condenser also decreases.

[0064] In this case, if the indoor fan 21 is blown into the room at the rotation speed of the indoor fan 21 during the heat storage heating operation without following the decrease in the condensation temperature, cold air will be supplied to the heated room. Therefore, from the viewpoint of maintaining the comfort of the user, the rotation speed of the indoor fan 21 is set by the method described below to avoid such supply of cold air into the room.

[0065] First, an instruction is issued from the determination unit 71 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, the calculation unit 73 calculates the internal volume of the refrigerant flow path of the heat exchanger that functions as a condenser in each operation mode based on the information regarding the internal volume of the refrigerant flow path stored in the storage unit 72.

[0066] Here, the "information regarding the internal volume of the refrigerant flow path" can include, for example, the information on 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. Further, it may include information on the total internal volume of the refrigerant flow path of the entire condenser in the combination of heat exchangers that serve as the condenser in each operation mode, and information such as the rotation speed of the indoor fan 21 associated with the combination (operation mode) of the heat exchangers.

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

[0068] In addition, the calculation unit 73 calculates the internal volume of the refrigerant flow path of the heat exchanger that serves as the condenser in the defrost heating operation, which is the operation mode after the switch. In the defrost heating operation, the indoor heat exchanger 2 and the outdoor heat exchanger 3 serve as the condensers, so the sum of the internal volumes of the refrigerant flow paths of each of them is calculated.

[0069] Then, the calculation unit 73 calculates the change rate of the internal volume of the condenser refrigerant flow path after the switch (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) with respect to the internal volume of the condenser refrigerant flow path before the switch (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) before switching the operation mode.

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

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

[0072] That is, when the determination unit 71 determines that the start condition of the defrosting and heating operation is satisfied, the determination unit 71 accesses the storage unit 72 and acquires information regarding the internal volume of the refrigerant flow path of each heat exchanger stored in the storage unit 72.

[0073] As described above, the storage unit 72 stores information regarding the internal volume of the refrigerant flow path of the entire condenser in the combination of heat exchangers that serve as the condenser in each operation mode. The determination unit 71 accesses the storage unit 72, acquires information regarding the internal volume of the refrigerant flow path from the storage unit 72, and sets the rotational speed of the indoor fan 21 based on the information regarding the internal volume of the refrigerant flow path.

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

[0075] Based on the instruction to switch the operation mode from the determination unit 71, the switching control unit 74 executes, for example, the switching of the switching valve 6. Specifically, when the operation mode is switched from the heat storage heating operation to the defrosting and heating operation, the switching control unit 74 switches the second switching valve 62 so that the refrigerant discharged from the compressor 1 that has been flowing through 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 rotational speed of the indoor fan 21 and the condensation temperature when the indoor fan 21 is controlled when the operation mode is changed in the refrigeration cycle device 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 the heat storage heating operation, and the operation mode after the switch is the defrosting heating operation. Also, among the lines extending from the left side to the right side of the graph along the passage of time, the upper solid line indicates the rotational speed (air volume) of the indoor fan provided in the indoor unit. On the other hand, the lower broken line indicates the condensation temperature.

[0078] When the operation mode is switched from the heat storage heating operation to the defrosting heating operation, as described above, the internal volume of the refrigerant flow path of the heat exchanger that serves as the condenser increases. Therefore, in the conventional control method, for example, as shown in FIG. 12, the pressure of the refrigerant flowing in the refrigerant circuit decreases, and the condensation temperature also decreases.

[0079] On the other hand, in the present embodiment, as described above, when the operation mode is switched from the heat storage heating operation to the defrosting heating operation, the rotational speed of the indoor fan 21 is changed, that is, control is performed to decrease the rotational speed of the indoor fan 21. The fact that the rotational speed of the indoor fan 21 is shown to decrease along with the switching control of the second switching valve 62 by the switching control unit 74 indicated by the dotted line parallel to the vertical axis in FIG. 3 shows this control.

[0080] By changing the rotational speed of the indoor fan 21 along with the switching of the operation mode in this way, a large decrease in the condensation temperature can be prevented, and the supply of cold air into the room can be avoided. Therefore, the comfort of the user can be maintained.

[0081] On the one hand, after the operation mode is switched from the heat storage heating operation to the defrosting heating operation, the condensation temperature in the defrosting heating operation is only slightly lower than the condensation temperature in the heat storage heating operation and generally shows a constant value. Thus, by performing the process of reducing the rotation speed of the indoor fan 21 at approximately the same time as when the operation mode is switched, for the condensation temperature, at least as shown in FIG. 12, the decrease in the condensation temperature is smaller than when the rotation speed of the indoor fan 21 decreases after some time has elapsed since the operation mode was switched.

[0082] So far, it has been described on the premise that the heat storage heating operation is being performed as the operation mode before the defrosting heating operation is started. However, for example, as operation modes of the heating operation, in addition to the heat storage heating operation, a heat storage utilization heating operation and a normal heating operation are also conceivable.

[0083] As described so far, the heat stored in the heat storage heat exchanger 4 during the heat storage heating operation has been used during the defrosting operation for the outdoor heat exchanger 3. In contrast, the heat storage utilization 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 utilization heating operation is, for example, an operation mode performed to satisfy the required heating capacity using the heat stored in the heat storage heat exchanger 4 when the outside air temperature is low and heat cannot be taken in by the outdoor heat exchanger 3. In the case of this operation mode, as shown in FIG. 7 to be described later, only the indoor heat exchanger 2 becomes the condenser, and both the heat storage heat exchanger 4 and the outdoor heat exchanger 3 become evaporators.

[0085] Next, the normal heating operation is an operation mode in which refrigerant is not passed through the heat storage heat exchanger 4 when the heating operation is performed. 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, a situation may be considered in which the heat storage material cannot store any more heat.

[0086] When the heat storage heat exchanger 4 is in such a state, even if the refrigerant is made to flow into the heat storage heat exchanger 4 for heat exchange, the heat storage effect cannot be expected, and it is unnecessary to make the refrigerant flow into the heat storage heat exchanger 4. Therefore, when performing heating operation in such a case, the operation 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 the normal heating operation.

[0087] Therefore, in the normal heating operation, only the indoor heat exchanger 2 serves as a condenser. On the other hand, the outdoor heat exchanger 3 functions as an evaporator. Regarding 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 operation mode is switched from such a heat storage utilization heating operation or from the normal heating operation to the defrost heating operation, the rotational speed of the indoor fan 21 is set based on the information regarding the internal volume of the refrigerant flow path of the heat exchanger serving as a condenser by the control device 7 as described above.

[0089] Note that it is premised that the operation mode is switched from the various heating operations described above to the defrost heating operation. In the case of a defrost operation without performing a heating operation, there is no possibility that cold air is supplied into the room by the indoor fan 21. Therefore, even if control to change the rotational 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 lower than in the case of the defrost heating operation.

[0090] The above is the description of the functions of each part of the control device 7 of the refrigeration cycle device S in the embodiment of the present invention. Therefore, next, the operation modes performed in the refrigeration cycle device S will be sequentially described using the circuit diagram of the refrigeration cycle device S in the embodiment of the present invention shown in FIGS. 4 to 8.

[0091] In the circuit diagrams shown in FIGS. 4 to 8, the refrigerant circuit C through which the refrigerant actually flows is indicated by a solid line. On the other hand, the refrigerant circuit C that constitutes the refrigerant circuit C but through which the refrigerant does not flow is indicated by a broken line. Also, the direction of the refrigerant flowing in the refrigerant circuit C is indicated by an arrow.

[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 a cooling operation. In the case of the 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 and 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. At this time, the opening degree of the first expansion valve 51 is fully open. Also, the refrigerant discharged from the compressor 1 also flows to the first switching valve 61, but flows from the second switching valve 62 to the outdoor heat exchanger 3 through the bypass circuit B1.

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

[0095] The refrigerant that has dissipated heat to the outside air in this way flows out of the outdoor heat exchanger 3 and is depressurized to a low-temperature and low-pressure refrigerant by passing through the third expansion valve 53. Then, the refrigerant that has become low-temperature and low-pressure flows into the indoor heat exchanger 2, and heat exchange is performed between the indoor heat exchanger 2 and the indoor air.

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

[0097] On the other hand, the refrigerant flow when the refrigeration cycle device S performs heat storage heating operation is as shown in FIG. 5. FIG. 5 is a refrigerant circuit diagram showing the refrigerant flow when the refrigeration cycle device S according to the embodiment of the present invention performs 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, heat exchange is performed between the refrigerant and the air flowing into the indoor unit in the indoor heat exchanger 2, and the 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 exchange is performed 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] In the refrigeration cycle device S according to the embodiment of the present invention, as described above, in addition to the indoor heat exchanger 2 and the outdoor heat exchanger 3, a heat storage heat exchanger 4 is provided. When the heat storage heating operation is executed, 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 heat of the refrigerant is stored in the heat storage material by performing heat exchange between the flowing-in refrigerant and 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 into the compressor 1 via the second switching valve 62.

[0102] FIG. 6 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 defrosting heating operation. The refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 via the first switching valve 61. Since this is a heating operation here, the indoor heat exchanger 2 functions as a condenser, and heat exchange is performed between the refrigerant and the air flowing into the indoor unit in the indoor heat exchanger 2, and the air heated by absorbing heat from the refrigerant is supplied 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 for melting the frost adhering to the outdoor heat exchanger 3 is executed.

[0104] The refrigerant flowing out of 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 opening degrees of the third expansion valve 53 and the second expansion valve 52 are fully open. In addition, the refrigerant flowing out of 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 of the heat storage heat exchanger 4 flows into the compressor 1 via the second switching valve 62.

[0105] Next, the flow of refrigerant when the refrigeration cycle device S performs heat storage utilization heating operation will be described. FIG. 7 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 heat storage utilization heating operation.

[0106] As shown in FIG. 7, the refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 2 via the first switching valve 61. In the case of heat storage utilization heating operation here, 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 that branches before reaching the first switching valve 61 is controlled by the switching control unit 74 to be fully closed.

[0107] The refrigerant flowing into the indoor heat exchanger 2 exchanges heat with the air flowing into the indoor unit in the indoor heat exchanger 2, and the 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 of the indoor heat exchanger 2 flows into the heat storage heat exchanger 4 through the confluence point C1 provided in the 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 flowing-in low-temperature and low-pressure refrigerant exchanges heat with the heat storage material. The refrigerant flowing out of the heat storage heat exchanger 4 flows into the compressor 1 through the second switching valve 62.

[0109] Also, 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 exchange is performed between the refrigerant and the outdoor air. The refrigerant flowing out of the outdoor heat exchanger 3 flows into the compressor 1 through the second switching valve 62, the bypass circuit B2, and the first switching valve 61.

[0110] In the case of heat storage utilization heating operation, as described above, the bypass circuit B2 employs an on-off valve instead of a check valve like the previous bypass circuit B1. By this on-off valve, the refrigerant flowing out of the outdoor heat exchanger 3 can be made to flow from the second switching valve 62 toward the first switching valve 61, and it becomes possible to return it to the compressor 1.

[0111] Finally, the flow of the refrigerant when the refrigeration cycle device S performs normal heating operation will be described. FIG. 8 is a refrigerant circuit diagram showing the flow of the refrigerant when the refrigeration cycle device 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 through the first switching valve 61. Then, heat exchange is performed between the refrigerant and the air flowing into the indoor unit in the indoor heat exchanger 2, and the 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 exchange is performed 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 it is not necessary to allow the refrigerant to flow into the heat storage heat exchanger 4, the first expansion valve 51 is fully closed to prevent the refrigerant discharged from the compressor 1 from flowing into the heat storage heat exchanger 4. Therefore, heat exchange does not occur between the heat storage material and the refrigerant in the heat storage heat exchanger 4 either. Also, the second expansion valve 52 is fully closed.

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

[0116] Note that there are various forms of heating operation as described above, but an example in which the operation mode switches from the heat storage heating operation to the defrost heating operation will be given and described below as before.

[0117] First, in the refrigeration cycle device S, the heat storage heating operation is started (ST1). Here, the conditions for starting the heat storage heating operation are set in advance, and the control device 7 determines whether or not the conditions are satisfied. 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. Thereby, the heat storage heating operation can be executed when the stored heat quantity 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 via the first switching valve 61, and also flows into the heat storage heat exchanger 4 via 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 for the outdoor heat exchanger 3 is necessary according to a preset shift condition to the defrosting operation (ST2). When the defrosting operation is not necessary (NO in ST2), the heat storage heating operation continues to be performed.

[0120] On the other hand, when the control device 7 (determination unit 71) determines that the condition for starting the defrosting heating operation is satisfied (YES in ST2), a switching process for switching the operation mode from the heat storage heating operation to the defrosting heating operation is executed (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 is switched (ST5). The detailed flow of the process using the calculation unit 73 in setting the rotation speed of the indoor fan 21 will be described with reference to FIG. 10. FIG. 10 is a flowchart showing the control flow when the operation mode changes in the refrigeration cycle device S according to the embodiment of the present invention.

[0123] In the calculation unit 73 that has received an instruction from the determination unit 71 regarding the switching of the operation mode from the heat storage heating operation to the defrosting heating operation, first, it accesses the storage unit 72 and calculates the sum of the internal volumes of the refrigerant flow paths of all the heat exchangers that serve 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 sum of the internal volumes of the refrigerant flow paths in these heat exchangers is calculated.

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

[0125] The calculation unit 73 calculates the change rate of the internal volume of the refrigerant flow path of the heat exchanger in the defrost heating operation after switching (the internal volume of the condenser refrigerant flow path after switching) with respect to the internal volume of the refrigerant flow path of the heat exchanger in the heat storage heating operation before switching the operation mode (the internal volume of the condenser refrigerant flow path before switching) (ST53). Then, the calculation unit 73 uses the calculated change rate to set the rotation speed of the indoor fan 21 after switching the operation mode to the defrost heating operation based on the value obtained by multiplying the rotation speed of the indoor fan 21 in the operation mode before switching 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, an instruction is given to 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 when setting the rotation speed of the indoor fan 21, instead of such a method, the determination unit 71 may adopt a method of acquiring information on the internal volume of the refrigerant flow path from the storage unit 72 based on the type of heating operation performed before the defrost heating operation when starting the defrost heating operation and setting the rotation speed of the indoor fan 21.

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

[0129] While the defrost heating operation is being executed, the control device 7 determines whether to end the defrost heating operation based on a preset end condition (ST7).

[0130] If it is determined by the control device 7 not to end the defrost heating operation (NO in ST7), the ongoing defrost heating operation is continued. On the other hand, if the result of the determination is to end the defrost heating operation (YES in ST7), the defrost heating operation is ended (ST8).

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

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

[0133] That is, so far, the case where the operation mode is switched and the heat exchanger serving as the condenser changes, resulting in an increase in the internal volume of the refrigerant flow path of the condenser, has been described. In this case, as described above, control is performed to reduce the rotation speed of the indoor fan 21. Conversely, when the operation mode is switched and the heat exchanger serving as the condenser changes, resulting in a decrease in the internal volume of the refrigerant flow path of the condenser and an increase in the condensation temperature, control is performed to increase the rotation speed of the indoor fan 21.

[0134] Such control is performed, for example, in a state where the operation mode is switched from the defrost heating operation to the heat storage heating operation. Therefore, in the operation of the refrigeration cycle device S described above, in the switching process when switching from the defrost heating operation to the heating operation, the setting is made to increase the rotation speed of the indoor fan 21.

[0135] Note that in the description herein, regarding the control of the switching valve 6 and the setting of the rotational speed of the indoor fan 21, the former was described first and the latter was described later. However, this order is merely for the convenience of explanation and does not imply any particular sequence. The control of the switching valve 6 and the setting of the rotational speed of the indoor fan 21 may be in the reverse order, or both may be performed simultaneously.

[0136] As described above, when the operation mode is switched from the heating operation to the defrosting heating operation, by controlling the rotational speed of the indoor fan 21 in accordance with the decrease in the condensation temperature, it is possible to prevent a sudden decrease or increase in the blowing temperature temporarily from the indoor unit. Therefore, even when the operation mode is switched, it is possible to suppress a decrease in comfort for the user.

[0137] Particularly, when cold air is supplied into the room due to a decrease in the condensation temperature, since the decrease in comfort for the user becomes significant, it is very effective to perform control to decrease the rotational speed of the indoor fan 21 based on the internal volume of the refrigerant flow path of the heat exchanger that serves as the condenser in such a case.

[0138] Note that the present invention is not limited to the above-described embodiment as it is, but is merely an example of the present invention. At the implementation stage, the components can be modified and embodied without departing from the gist thereof, and various changes or improvements can be made to the above-described embodiment. Also, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiment.

[0139] For example, some components may be deleted from all the components shown in the embodiment. Further, components from different embodiments may be appropriately combined, and forms with such changes or improvements may also be included in the present invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0140] For example, in the processing flow for switching the above-described operation modes, when the determination unit 71 determines that the conditions for starting the defrosting heating operation are satisfied, the switching valve 6 is switched, and the rotation speed of the indoor fan 21 is set, and the indoor unit is instructed to rotate the indoor fan 21 at the set rotation speed of the indoor fan 21.

[0141] However, instead of such processing, for example, when the determination unit 71 determines that the start condition of the defrosting heating operation is satisfied, first, the determination unit 71 sets the rotation speed of the indoor fan 21 and instructs the indoor unit of the set rotation speed.

[0142] In this case, next, the switching valve 6 is controlled in this process. However, before the control of the switching valve 6 is executed, the rotation speed of the indoor fan 21 is gradually decreased. And when the switching valve 6 is actually switched and the defrosting heating operation is started, the rotation speed of the indoor fan 21 may already be decreased to the set rotation speed.

[0143] By performing such processing, it is possible to better match the timing of switching the operation mode and the timing of processing for changing the rotation speed of the indoor fan 21, which further contributes to maintaining comfort for the user.

[0144] Also, until now, when setting the rotation speed of the indoor fan 21, it has been described that the calculation unit 73 calculates the change rate of the internal volume of the condenser refrigerant flow path after switching with respect to the internal volume of the condenser refrigerant flow path before switching when switching the operation mode. However, when calculating the change rate by the calculation unit 73, 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 device S in the embodiment of the present invention, various explanations have been made on the premise that the 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 is provided. However, the above-described explanations also apply to the case of a refrigeration cycle device provided with a refrigerant circuit in which these heat exchangers are connected in series.

[0146] In the description of the heat storage utilization heating operation described above, the case where the outdoor heat exchanger functions as an evaporator in addition to the heat storage heat exchanger was taken as an example. However, in the heat storage utilization heating operation, it is not always necessary to make the outdoor heat exchanger function as an evaporator, and it is also possible to make only the heat storage heat exchanger function as an evaporator.

[0147] Regarding the technology described in the embodiments of the present invention, the following configurations can also be adopted. (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 having a plurality of switching valves that switch the 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 valves, The control device is a refrigeration cycle device characterized in that when switching the operation between the heating operation and the defrosting operation, the rotation speed of the indoor fan is changed. (2) The control device includes at least a storage unit 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, When the control device performs control to change the rotation speed of the indoor fan, the rotation speed of the indoor fan is set based on the information regarding the internal volume of the refrigerant flow path. The refrigeration cycle device according to (1) above. (3) The control device further A calculation unit is provided that calculates the sum of the internal volumes of all the condenser refrigerant flow paths of the heat exchanger that functions as a condenser in each operation mode based on the information regarding the internal volume of the refrigerant flow path stored in the memory unit. The calculation unit calculates a change rate of the internal volume of the post-switching condenser refrigerant flow path with respect to the internal volume of the pre-switching condenser refrigerant flow path before switching the operation mode. When the control device performs control to change the rotation speed of the indoor fan, the rotation speed of the indoor fan after switching the operation mode is set based on the change rate, in the refrigeration cycle device according to (2) above. (4) When the control device switches the switching valve so as 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 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, the control device performs control to decrease the rotation speed of the indoor fan, in the refrigeration cycle device according to any one of (1) to (3) above. (5) When the control device switches the switching valve so as to switch from a heat storage utilization 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 functions as an evaporator, the control device performs control to decrease the rotation speed of the indoor fan, in the refrigeration cycle device according to any one of (1) to (3) above. (6) When the control device switches the switching valve so as to switch 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, the control device performs control to decrease the rotation speed of the indoor fan, in the refrigeration cycle device according to any one of (1) to (3) above. (7) The internal volume of the refrigerant flow path of the heat storage heat exchanger is smaller than the internal volume of the refrigerant flow path of the outdoor heat exchanger, and the refrigeration cycle device according to any one of (1) to (6) above is characterized in that. (8) In a refrigerant circuit for circulating refrigerant, a compressor for compressing the refrigerant, an indoor heat exchanger for exchanging heat between indoor air and the refrigerant, an outdoor heat exchanger for exchanging heat between outdoor air and the refrigerant, a heat storage heat exchanger for exchanging heat between a heat storage material and the refrigerant, a plurality of switching valves for switching the circulation path of the refrigerant in the refrigerant circuit in 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 for passing indoor air through the indoor heat exchanger, a control device for controlling the indoor fan and the switching valve, and the control device, performs a step of determining whether to switch the operation mode between the heating operation and the defrosting operation, when it is determined to switch the operation mode, performs a step of switching with the switching valve, performs a control of changing the rotational speed of the indoor fan according to the operation mode after switching, and A control method for a refrigeration cycle device, characterized by comprising the above. (9) In the step in which the control device performs control to change the rotational speed of the indoor fan, at least, the rotational speed of the indoor fan is set based on information regarding the internal volume of each refrigerant flow path of the indoor heat exchanger, the outdoor heat exchanger, and the heat storage heat exchanger, and the control method for a refrigeration cycle device according to (8) above is characterized in that. (10) In the step before the step in which the control device performs control to change the rotational speed of the indoor fan, based on information regarding the internal volume of the refrigerant flow path, calculates the sum of the internal volumes of all the condenser refrigerant flow paths of the heat exchanger that functions as a condenser in each operation mode, Calculating a change rate of the internal volume of the condenser refrigerant flow path after switching with respect to the internal volume of the condenser refrigerant flow path before switching before switching the operation mode; Setting the rotation speed of the indoor fan after switching the operation mode based on the change rate; The control method of the refrigeration cycle device according to the above (9), characterized by comprising the above steps. (11) The step in which the control device performs control to change the rotation speed of the indoor fan is When the control device switches the switching valve, the indoor heat exchanger and the heat storage heat exchanger function as condensers, and the outdoor heat exchanger functions as an evaporator. When switching from the heat storage heating operation to the 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, the step of performing control to reduce the rotation speed of the indoor fan. The control method of the refrigeration cycle device according to any one of the above (8) to (10), characterized in that it is. (12) The step in which the control device performs control to change the rotation speed of the indoor fan is When the control device switches the switching valve, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger and the heat storage heat exchanger function as evaporators. When switching from the heat storage utilization heating operation to the 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, the step of performing control to reduce the rotation speed of the indoor fan. The control method of the refrigeration cycle device according to any one of the above (8) to (10), characterized in that it is. (13) The step in which the control device performs control to change the rotation speed of the indoor fan is When the control device switches the switching valve, the indoor heat exchanger functions as a condenser, and from the normal heating operation in which only the outdoor heat exchanger functions as an evaporator, to the 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, the control method of the refrigeration cycle device according to the above (8), characterized in that it performs control to reduce the rotational speed of the indoor fan.

Explanation of Signs

[0148] 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 ··· Switching valve, 61 ··· First switching valve, 62 ··· Second switching valve, 7 ··· Control device, 71 ··· Judgment unit, 72 ··· Storage unit, 73 ··· Calculation unit, 74 ··· Switching 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 having a plurality of switching valves that switch the circulation path of the refrigerant in 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 indoor air through the indoor heat exchanger; a control device that controls the indoor fan and the switching valves; The control device is characterized in that when switching the operation between the heating operation and the defrosting operation, the rotational speed of the indoor fan is changed. A refrigeration cycle device.

2. The control device includes at least a storage unit that stores information regarding the internal volumes of the refrigerant flow paths of the indoor heat exchanger and the outdoor heat exchanger respectively; When the control device performs control to change the rotational speed of the indoor fan, the rotational speed of the indoor fan is set based on information regarding the internal volume of the refrigerant flow path. The refrigeration cycle device according to Claim 1.

3. The control device further includes a calculation unit that calculates the sum of the internal volumes of all the condenser refrigerant flow paths of the heat exchanger that functions as a condenser in each operation mode based on the information regarding the internal volume of the refrigerant flow path stored in the storage unit; The calculation unit calculates a change rate of the internal volume of the post-switching condenser refrigerant flow path with respect to the internal volume of the pre-switching condenser refrigerant flow path before switching the operation mode; When the control device performs control to change the rotational speed of the indoor fan, the rotational speed of the indoor fan after switching the operation mode is set based on the change rate. The refrigeration cycle device according to Claim 2.

4. When the control device switches the switching valve so that the indoor heat exchanger and the heat storage heat exchanger function as condensers and the outdoor heat exchanger functions as an evaporator in a heat storage heating operation, and switches to a defrosting 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, the control device performs control to decrease the rotational speed of the indoor fan. The refrigeration cycle device according to Claim 1.

5. When the control device switches the switching valve, the control device controls the indoor heat exchanger to function as a condenser and the heat storage heat exchanger to function as an evaporator in a heat storage utilization heating operation, and switches to a defrosting 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. When switching, the control device performs control to reduce the rotational speed of the indoor fan. The refrigeration cycle device according to claim 1, characterized in that.

6. When the control device switches the switching valve, the control device controls the indoor heat exchanger to function as a condenser and the outdoor heat exchanger alone to function as an evaporator in a normal heating operation, and switches to a defrosting 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. When switching, the control device performs control to reduce the rotational speed of the indoor fan. The refrigeration cycle device according to claim 1, characterized in that.

7. The refrigeration cycle device according to any one of claims 1 to 6, characterized in that the internal volume of the refrigerant flow path of the heat storage heat exchanger is smaller than the internal volume of the refrigerant flow path of the outdoor heat exchanger.

8. In a refrigerant circuit for circulating refrigerant, a compressor for compressing the refrigerant; an indoor heat exchanger for exchanging heat between indoor air and the refrigerant; an outdoor heat exchanger for exchanging heat between outdoor air and the refrigerant; a heat storage heat exchanger for exchanging heat between a heat storage material and the refrigerant; a plurality of switching valves for switching 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; are connected, an indoor fan for passing the indoor air through the indoor heat exchanger; a control device for controlling the indoor fan and the switching valve; is provided, The control device, a step of determining whether to switch the operation mode between the heating operation and the defrosting operation; when it is determined to switch the operation mode, a step of switching with the switching valve; a step of performing control to change the rotational speed of the indoor fan according to the operation mode after switching the rotational speed of the indoor fan; is provided, A control method for a refrigeration cycle device, characterized by comprising.

9. In the step in which the control device performs control to change the rotational speed of the indoor fan, The control method of a refrigeration cycle device according to claim 8, characterized in that at least the rotational speed of the indoor fan is set based on information regarding the internal volume of each refrigerant flow path of the indoor heat exchanger and the outdoor heat exchanger.

10. Before the step in which the control device performs control to change the rotational speed of the indoor fan, Based on the information regarding the internal volume of the refrigerant flow path, calculating the sum of the internal volumes of all condenser refrigerant flow paths of the heat exchanger functioning as a condenser in each operation mode; Calculating the change rate of the internal volume of the post-switching condenser refrigerant flow path after switching the operation mode with respect to the internal volume of the pre-switching condenser refrigerant flow path before switching; Setting the rotational speed of the indoor fan after switching the operation mode based on the change rate; The control method of a refrigeration cycle device according to claim 9, characterized by comprising the above.

11. The step in which the control device performs control to change the rotational speed of the indoor fan is When the control device switches the switching valve, 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 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, the step of performing control to decrease the rotational speed of the indoor fan, which is the control method of a refrigeration cycle device according to claim 8.

12. The step in which the control device performs control to change the rotational speed of the indoor fan is When the control device switches the switching valve, from a heat storage utilization 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, the step of performing control to decrease the rotational speed of the indoor fan, which is the control method of a refrigeration cycle device according to claim 8.

13. The step in which the control device performs control to change the rotational speed of the indoor fan is The control device performs control to reduce the rotational 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. The control method of the refrigeration cycle device according to claim 8, characterized in that it is a step of performing such control.

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