Air conditioner

Abstract

An air conditioner according to an embodiment is connected to a refrigerant circuit for circulating a refrigerant: a compressor for compressing the refrigerant; an indoor heat exchanger; an outdoor heat exchanger; a heat storage heat exchanger for exchanging heat between the heat storage material and the refrigerant; a plurality of expansion valves, the opening of which can be adjusted; and a plurality of switching valves for switching the circulation path of the refrigerant in the refrigerant circuit between a heat storage and heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as a condenser and the outdoor heat exchanger function as an evaporator, and a defrosting and heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as a condenser and the outdoor heat exchanger function as an evaporator. The defrosting and heating operation enables the indoor heat exchanger and the outdoor heat exchanger to function as condensers, and enables the heat storage heat exchanger to function as an evaporator. One of the plurality of expansion valves is provided upstream of the outdoor heat exchanger when the outdoor heat exchanger functions as a condenser, and the pressure of the refrigerant flowing into the outdoor heat exchanger is reduced by the one expansion valve.

Description

Technical Field

[0001] An embodiment of the present invention relates to an air conditioner. Background Art

[0002] At present, there is known an air conditioner equipped with a heat storage heat exchanger for exchanging heat between the refrigerant discharged from the compressor and the heat storage material. In this air conditioner, in order to continue the heating operation while performing the defrosting process of melting the frost generated in the outdoor heat exchanger, a conventional technology of switching between the heat storage heating operation and the defrosting heating operation is adopted.

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

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-17738 Summary of the invention

[0005] However, in the above-mentioned prior art, the pressure (condensation temperature of the two-phase region) of the refrigerant flowing into the indoor heat exchanger and the outdoor heat exchanger during defrosting and heating operation is the same. In order to perform indoor heating, the condensation temperature is set to about 40°C, and the temperature of the frost in the outdoor heat exchanger is below 0°C, so the temperature of the refrigerant supplied to the outdoor heat exchanger is much higher than the temperature required for defrosting. As a result, there is a problem that a large amount of supercooled liquid-phase refrigerant is distributed in the outdoor heat exchanger, the flow rate of the refrigerant flowing into the indoor heat exchanger becomes smaller, and the heating capacity decreases.

[0006] The disclosed technology has been made in view of the above-mentioned problems, and an object of the disclosed technology is to provide an air conditioner capable of suppressing a decrease in indoor heating capacity during defrosting and heating operation.

[0007] An air conditioner in one aspect of the present disclosure is connected to a refrigerant circuit for circulating a refrigerant, and is provided with: 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 expansion valves capable of adjusting the opening degree; and a plurality of switching valves for switching the circulation path of the refrigerant in the refrigerant circuit between a heat storage heating operation and a defrosting heating operation. Switching, the heat storage heating operation makes the indoor heat exchanger and the heat storage heat exchanger function as a condenser, and the outdoor heat exchanger functions as an evaporator, the defrost heating operation makes the indoor heat exchanger and the outdoor heat exchanger function as a condenser, and the heat storage heat exchanger functions as an evaporator, one of the multiple expansion valves is arranged upstream of the outdoor heat exchanger when the outdoor heat exchanger functions as a condenser, and the refrigerant flowing into the outdoor heat exchanger is reduced in pressure by this expansion valve.

[0008] The disclosed air conditioner can suppress a decrease in indoor heating capacity during defrosting and heating operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A This is a circuit diagram showing an example of the air conditioner according to the embodiment.

[0010] Figure 1B This is a circuit diagram showing an example of the air conditioner according to the embodiment.

[0011] Figure 2 This is a block diagram showing an example of an air conditioner according to an embodiment.

[0012] Figure 3 This is a flowchart showing an example of the operation of the air conditioner according to the embodiment.

[0013] Figure 4 It is an explanatory diagram for explaining the state during the heat storage / heating operation of the air conditioner according to the embodiment.

[0014] Figure 5 This is a diagram showing an example of a timing chart when the air conditioner according to the embodiment starts the defrosting operation.

[0015] Figure 6 It is an explanatory diagram for explaining switching of the operating state of the air conditioner according to the embodiment.

[0016] Figure 7 It is an explanatory diagram for explaining the state during the defrosting / heating operation of the air conditioner according to the embodiment.

[0017] Figure 8This is a diagram showing an example of a timing chart when the air conditioner according to the embodiment is released from the defrosting operation. DETAILED DESCRIPTION

[0018] Hereinafter, the air conditioner of the embodiment will be described with reference to the accompanying drawings. In the embodiment, the same symbols are marked on the structures with the same functions, and repeated descriptions are omitted. In addition, the air conditioner described in the following embodiment is only an example and does not limit the embodiment. In addition, the various embodiments shown below can also be appropriately combined within a reasonable range.

[0019] Figure 1A , Figure 1B 1 is a circuit diagram showing an example of an air conditioner according to an embodiment. Figure 1A As shown, the air conditioner 1 is a device that performs indoor cooling and heating, for example, under the control of a control device 20. The air conditioner 1 includes a compressor 11 for compressing a refrigerant such as R32, an indoor heat exchanger 14 for exchanging heat between indoor air and the refrigerant, an outdoor heat exchanger 15 for exchanging heat between outdoor air and the refrigerant, and a heat storage heat exchanger 16 for exchanging heat between a heat storage material 16a and the refrigerant. The above-mentioned devices are connected by a flow path (refrigerant pipe), thereby forming a refrigerant circuit 10 for circulating the refrigerant.

[0020] The refrigerant circuit 10 has flow paths 10a to 10f through which the refrigerant flows. The flow paths 10a to 10f are connected to a first three-way valve 12a, a second three-way valve 12b, and a third three-way valve 12c for switching the circulation path of the refrigerant, and a first expansion valve 13a, a second expansion valve 13b, and a third expansion valve 13c capable of adjusting the opening. The first three-way valve 12a, the second three-way valve 12b, and the third three-way valve 12c are examples of switching valves, and may be replaced by a four-way valve or the like.

[0021] In the following description, when there is no need to distinguish the first three-way valve 12a, the second three-way valve 12b, the third three-way valve 12c, etc., they are collectively referred to as the three-way valve 12. Similarly, when there is no need to distinguish the first expansion valve 13a, the second expansion valve 13b, the third expansion valve 13c, etc., they are collectively referred to as the expansion valve 13.

[0022] The flow path 10a in the refrigerant circuit 10 connects the discharge side of the compressor 11 to the first three-way valve 12a, the second three-way valve 12b, and the third three-way valve 12c, respectively. Specifically, the flow path 10a is divided into a path for the refrigerant to flow to the first three-way valve 12a and a path for the refrigerant to flow to the second three-way valve 12b and the third three-way valve 12c through the first branch 10aa. The above-mentioned path for the refrigerant to flow to the second three-way valve 12b and the third three-way valve 12c is divided into paths for the refrigerant to flow to the second three-way valve 12b and the third three-way valve 12c respectively through the second branch 10ab. In addition, the third expansion valve 13c is connected between the first branch 10aa and the second branch 10ab.

[0023] In addition, Figure 1A In the circuit example of the air conditioner 1 shown in FIG. 1 , a common third expansion valve 13c is used for both the outdoor heat exchanger 15 and the heat storage heat exchanger 16 in the flow path 10a on the discharge side of the compressor 11. Figure 1B As shown in the circuit example of the air conditioner 1a shown in FIG. 1 , the third expansion valve 13ca and the fourth expansion valve 13cb corresponding to the outdoor heat exchanger 15 and the heat storage heat exchanger 16 are provided in the respective flow paths of the outdoor heat exchanger 15 and the heat storage heat exchanger 16 branched by the branch 10ac and the branch 10ad. However, the structure in which the third expansion valve 13c is used in common for both the outdoor heat exchanger 15 and the heat storage heat exchanger 16 requires only one expansion valve, thereby reducing the cost.

[0024] The flow path 10b in the refrigerant circuit 10 connects the suction side of the compressor 11 to the first three-way valve 12a, the second three-way valve 12b, and the third three-way valve 12c, respectively. The flow path 10c connects the first three-way valve 12a to the indoor heat exchanger 14. The flow path 10d connects the second three-way valve 12b to the outdoor heat exchanger 15. The flow path 10e connects the third three-way valve 12c to the heat storage heat exchanger 16.

[0025] The flow path 10f in the refrigerant circuit 10 connects the indoor heat exchanger 14, the outdoor heat exchanger 15, and the thermal storage heat exchanger 16. A first expansion valve 13a is connected between the indoor heat exchanger 14 in the flow path 10f and a branch 10fa for branching from or merging with the indoor heat exchanger 14. Similarly, a second expansion valve 13b is connected between the thermal storage heat exchanger 16 in the flow path 10f and a branch 10fa for branching from or merging with the thermal storage heat exchanger 16.

[0026] The air conditioner 1 has temperature sensors 17a to 17f for detecting the temperature of each part. The temperature sensor 17a is a sensor for detecting the temperature of the refrigerant discharged from the compressor 11. The temperature sensor 17b is a sensor for detecting the temperature of the indoor heat exchanger 14. The temperature sensor 17c is a sensor for detecting the temperature of the outdoor heat exchanger 15.

[0027] The temperature sensor 17d is a sensor for detecting the temperature of the heat storage material 16a. The temperature sensor 17e is a sensor for detecting the temperature of the heat storage heat exchanger 16. The temperature sensor 17f is a sensor for detecting the temperature (liquid pipe temperature) of the refrigerant flowing between the heat storage heat exchanger 16 and the second expansion valve 13b in the flow path 10f. In addition, in the following description, when there is no need to specifically distinguish between the temperature sensors 17a to 17f, etc., they are collectively referred to as the temperature sensor 17. In addition, the temperature sensor 17 also includes a temperature sensor for detecting the indoor temperature, etc., but this is not specifically shown in the figure.

[0028] Here, a description will be given of a refrigerant circulation path during the heat storage heating operation and a refrigerant circulation path during the defrosting heating operation in the refrigerant circuit 10 .

[0029] In the thermal storage heating operation, the control device 20 of the air conditioner 1 switches the three-way valves 12 to circulate the refrigerant so that the indoor heat exchanger 14 and the thermal storage heat exchanger 16 function as condensers and the outdoor heat exchanger 15 functions as an evaporator.

[0030] Specifically, the control device 20 switches the first three-way valve 12a so that the refrigerant discharged from the compressor 11 flows to the indoor heat exchanger 14 via the flow paths 10a and 10c. Similarly, the control device 20 switches the third three-way valve 12c so that the refrigerant discharged from the compressor 11 flows to the thermal storage heat exchanger 16 via the flow path 10a, the third expansion valve 13c, and the flow path 10e. In addition, the control device 20 switches the second three-way valve 12b so that the refrigerant that enters the flow path 10f from the indoor heat exchanger 14 and the thermal storage heat exchanger 16 and is decompressed by the first expansion valve 13a and the second expansion valve 13b returns to the compressor 11 via the flow paths 10d and 10b after passing through the outdoor heat exchanger 15.

[0031] In the defrosting and heating operation, the control device 20 of the air conditioner 1 switches the plurality of three-way valves 12 to circulate the refrigerant so that the indoor heat exchanger 14 and the outdoor heat exchanger 15 function as condensers and the heat storage heat exchanger 16 functions as an evaporator.

[0032] Specifically, the control device 20 switches the first three-way valve 12a so that the refrigerant discharged from the compressor 11 flows to the indoor heat exchanger 14 via the flow paths 10a and 10c. Similarly, the control device 20 switches the second three-way valve 12b so that the refrigerant discharged from the compressor 11 flows to the outdoor heat exchanger 15 via the flow paths 10a and 10d. At this time, the refrigerant flowing to the outdoor heat exchanger 15 is decompressed by the third expansion valve 13c provided on the flow path 10a. In addition, the control device 20 switches the third three-way valve 12c so that the refrigerant entering the flow path 10f from the indoor heat exchanger 14 and the outdoor heat exchanger 15 returns to the compressor 11 via the flow paths 10e and 10b after passing through the heat storage heat exchanger 16. At this time, the refrigerant entering the flow path 10f from the indoor heat exchanger 14 is decompressed by the first expansion valve 13a.

[0033] Figure 2 1 is a block diagram showing an example of the air conditioner 1 according to the embodiment. Figure 2 As shown, the air conditioner 1 includes a compressor 11, a three-way valve 12, an expansion valve 13, an outdoor fan 31, an indoor fan 32, and a control device 20. The control device 20 is electrically connected to a temperature sensor 17 for controlling each part.

[0034] The outdoor fan 31 is arranged inside an outdoor unit (not particularly shown) provided with an outdoor heat exchanger 15. The outdoor fan 31 is controlled by the control device 20 to blow the outdoor air in a manner that the outdoor air is in thermal contact with the outdoor heat exchanger 15. The indoor fan 32 is arranged inside an indoor unit (not particularly shown). The indoor fan 32 is controlled by the control device 20 to blow the indoor air in a manner that the indoor air is in thermal contact with the indoor heat exchanger 14 and the indoor air after thermal contact with the indoor heat exchanger 14 is blown from the indoor unit to the indoor room.

[0035] The control device 20 is a computer as an example of a control unit, and includes a storage device 21 and a CPU 22 (CPU: Central Processing Unit). The storage device 21 is used to store computer programs installed in the control device 20 and to store information used by the CPU 22. The CPU 22 processes information and controls the operation of the air conditioner 1 by executing the computer program installed in the control device 20.

[0036] The control device 20 receives various settings (heating operation or cooling operation and its set temperature, etc.) implemented through the operating unit (not shown) and the detection results of the temperature sensor 17 to control the compressor 11, the three-way valve 12, the expansion valve 13, the outdoor fan 31 and the indoor fan 32.

[0037] Specifically, the storage device 21 stores information such as parameters or formulas / tables, which are used by the CPU 22 to calculate control values ​​for controlling the compressor 11, the three-way valve 12, the expansion valve 13, the outdoor fan 31, and the indoor fan 32 based on the detection results of the temperature sensor 17. The CPU 22 controls the compressor 11, the three-way valve 12, the expansion valve 13, the outdoor fan 31, and the indoor fan 32 based on the information stored in the storage device 21 and the control values ​​calculated based on the detection results of the temperature sensor 17.

[0038] Figure 3 1 is a flowchart showing an example of the operation of the air conditioner 1 according to the embodiment. Figure 3 As shown, upon receiving the instruction to start the heating operation, the control device 20 starts the process and starts the heat storage heating operation (S11).

[0039] Specifically, the control device 20 switches the first three-way valve 12a to connect the flow paths 10a and 10c, so that the indoor heat exchanger 14 functions as a condenser. In addition, the control device 20 switches 12b to connect the flow paths 10d and 10b, so that the outdoor heat exchanger 15 functions as an evaporator. In addition, the control device 20 switches the third three-way valve 12c to connect the flow paths 10a and 10e, so that the heat storage heat exchanger 16 functions as a condenser. In addition, the control device 20 performs initial opening control so that the openings of the first expansion valve 13a, the second expansion valve 13b, and the third expansion valve 13c become the initial values ​​during heating operation. The initial value is set to ensure stability (and startability) at startup. The first expansion valve 13a is set to an opening that does not excessively increase the discharge temperature and avoids the reflux of liquid into the compressor. The second expansion valve 13b is set to an opening degree that can prevent liquid from accumulating in the thermal storage heat exchanger 16 and prevent an excessive flow rate of the refrigerant flowing to the thermal storage heat exchanger 16. The third expansion valve is set to an opening degree that can ensure an operating differential pressure of the second three-way valve 12b and prevent an excessive flow rate of the refrigerant flowing to the thermal storage heat exchanger 16. In addition, the control device 20 starts the indoor fan 32, the outdoor fan 31, and the compressor 11.

[0040] Next, the control device 20 controls (adjusts) the opening degree of the expansion valve 13 using the control value calculated based on the detection result of the temperature sensor 17 ( S12 ).

[0041] Specifically, the control device 20 performs a target discharge temperature control on the opening of the first expansion valve 13a so that the discharge temperature of the compressor 11 becomes the target discharge temperature. In addition, the control device 20 performs a thermal storage heat exchanger target subcooling degree control on the opening of the second expansion valve 13b so that the subcooling degree at the outlet of the thermal storage heat exchanger 16 becomes the target subcooling degree. In addition, the control device 20 performs a thermal storage heat exchanger target condensing temperature control on the opening of the third expansion valve 13c so that the condensing temperature of the thermal storage heat exchanger 16 becomes the target condensing temperature.

[0042] Figure 4 1 is an explanatory diagram for explaining the state of the air conditioner during the heat storage / heating operation according to the embodiment. Figure 4 As shown, during the heat storage / heating operation, the control device 20 controls the openings of the first expansion valve 13a, the second expansion valve 13b, and the third expansion valve 13c based on the control value calculated based on the input of the detection result of the temperature sensor 17.

[0043] Specifically, the control device 20 calculates the target discharge temperature based on the temperature (condensing temperature) of the indoor heat exchanger 14 detected by the temperature sensor 17b and the temperature (evaporating temperature) of the outdoor heat exchanger 15 detected by the temperature sensor 17c. Next, the control device 20 adjusts the opening of the first expansion valve 13a so that the discharge temperature of the refrigerant detected by the temperature sensor 17a approaches the calculated target discharge temperature.

[0044] In addition, the control device 20 calculates the thermal storage heat exchanger subcooling degree based on the liquid pipe temperature of the thermal storage heat exchanger 16 detected by the temperature sensor 17f and the temperature (condensing temperature) of the thermal storage heat exchanger 16 detected by the temperature sensor 17e. Then, the control device 20 controls the opening degree of the second expansion valve 13b so that the calculated thermal storage heat exchanger subcooling degree approaches the target subcooling degree of the thermal storage heat exchanger 16 stored in advance.

[0045] In addition, the control device 20 calculates the target condensing temperature of the thermal storage heat exchanger 16 based on the temperature of the thermal storage material 16a detected by the temperature sensor 17d. Next, the control device 20 controls the opening of the third expansion valve 13c so that the temperature (condensing temperature) of the thermal storage heat exchanger 16 detected by the temperature sensor 17e approaches the calculated target condensing temperature.

[0046] return Figure 3, following S12, the control device 20 determines whether the defrost start condition is satisfied (S13). For example, the control device 20 determines that the defrost start condition is satisfied when the temperature of the outdoor heat exchanger 15 satisfies a prescribed temperature condition (when the temperature of the outside air is 2°C, the temperature of the outdoor heat exchanger 15 is -6°C or less). In addition, the control device 20 may also determine that the defrost start condition is satisfied when not only the temperature of the outdoor heat exchanger 15 satisfies a prescribed condition but also the duration of the thermal storage heating operation satisfies a prescribed condition (for example, the continuous operation time is longer than a prescribed time).

[0047] When the defrosting start condition is not satisfied (S13: No), the control device 20 puts the process on standby. When the defrosting start condition is satisfied (S13: Yes), the control device 20 performs the processes of S14 to S19 to start the defrosting / heating operation.

[0048] Specifically, the control device 20 changes the speed of the indoor fan 32 to the speed during defrosting (a), and changes the speed of the compressor 11 to the speed when defrosting starts (b) (S14). The speed during defrosting (a) should be set to a speed at which the wind speed does not make the user feel the cold wind. The speed at the start of defrosting (b) should be set to a speed that can ensure the circulation amount of the refrigerant and does not produce abnormal noise when switching the three-way valve 12. Next, the control device 20 fixes the opening of the first expansion valve 13a (discharge temperature control is not running), and switches the third three-way valve 12c to connect the flow paths 10e and 10b, so that the heat storage heat exchanger 16 functions as an evaporator (S15).

[0049] Next, the control device 20 fixes the second expansion valve 13b to the defrosting pulse (c) (S16). The defrosting pulse (c) is set to a pulse corresponding to the opening that can ensure the circulation volume during defrosting and heating. Thus, the second expansion valve 13b is fixed to the opening corresponding to the defrosting.

[0050] Next, the control device 20 switches the second three-way valve 12b to connect the flow paths 10a and 10b, causes the outdoor heat exchanger 15 to function as a condenser, and stops the outdoor fan 31 (S17).

[0051] Next, the control device 20 changes the third expansion valve 13c to the initial pulse (d) during defrosting, and changes the speed of the compressor 11 to the speed (e) during defrosting (S18). The initial pulse (d) during defrosting is set to a pulse corresponding to an opening that can exert the desired heating capacity even when the temperature of the outdoor heat exchanger 15 is low and a relatively large amount of refrigerant flows to the outdoors. The speed (e) during defrosting is set to a speed at which the low pressure is not lower than the lower limit of the compressor 11 during the defrosting operation and the defrosting time is the shortest. As a result, in the air conditioner 1, the third expansion valve 13c is set to the initial opening at the start of defrosting, and the defrosting / heating operation is started on this basis.

[0052] Figure 5 FIG. 2 is an example of a timing chart when the air conditioner of the embodiment starts defrosting operation. Figure 5 As shown, after the defrosting operation starts, the air conditioner 1 changes the rotation speed of the indoor fan 32 to the defrosting rotation speed (a: Lo wind) at time t1.

[0053] Next, at time t2, the air conditioner 1 changes the speed of the compressor 11 to the defrosting start speed (87 rps in the example shown). Next, at time t3, the air conditioner 1 switches the third three-way valve 12c to change the heat storage heat exchanger 16 from a condenser (heat storage) to an evaporator (heat release). Next, at time t4, the second expansion valve 13b of the air conditioner 1 is fixed to the defrosting pulse (200 pls in the example shown).

[0054] Next, at time t5, the air conditioner 1 switches the second three-way valve 12b, so that the outdoor heat exchanger 15 changes from an evaporator (heat absorption) to a condenser (heat release, defrosting). Next, at time t6, the air conditioner 1 stops the outdoor fan 31. Next, at time t7, the third expansion valve 13c of the air conditioner 1 changes to the initial pulse during defrosting (125 pls in the example shown in the figure). Next, at time t8, the air conditioner 1 changes the speed of the compressor 11 to the speed during defrosting (130 rps in the example shown in the figure).

[0055] return Figure 3 , following S18, the control device 20 controls the opening of the third expansion valve 13c according to the temperature of the outdoor heat exchanger 15 detected by the temperature sensor 17c (S19). Specifically, the control device 20 increases the opening of the third expansion valve 13c as the temperature of the outdoor heat exchanger 15 rises. Thus, by adjusting the pressure of the refrigerant flowing into the outdoor heat exchanger 15, the temperature of the refrigerant can be adjusted to the minimum temperature required for defrosting, thereby suppressing the distribution of a large amount of supercooled liquid-phase refrigerant in the outdoor heat exchanger 15, thereby suppressing the flow rate of the refrigerant flowing into the indoor heat exchanger 14 from becoming smaller, thereby suppressing the reduction of the heating capacity.

[0056] Figure 61 is an explanatory diagram for explaining the switching of the operating state of the air conditioner 1 according to the embodiment. Figure 6 In the figure, the shadows of the indoor heat exchanger 14, the outdoor heat exchanger 15, and the heat storage heat exchanger 16 indicate whether they function as a condenser (with shadows) or as an evaporator (without shadows). In addition, the shade of the shadows indicates the temperature state of the refrigerant when it functions as a condenser (the thicker the shadow, the higher the temperature). Similarly, the lines in the flow paths 10a to 10f of the refrigerant circuit 10 indicate the temperature of the refrigerant flowing in the flow paths (the narrower the interval between the dotted lines, the higher the temperature), and the part where the refrigerant does not flow is indicated by a solid line.

[0057] like Figure 6 As shown, in the heat storage / heating operation (S1), the air conditioner 1 circulates the refrigerant in such a manner that the indoor heat exchanger 14 and the heat storage heat exchanger 16 function as a condenser and the outdoor heat exchanger 15 functions as an evaporator. Here, the first expansion valve 13a adjusts the discharge temperature of the refrigerant discharged from the compressor 11 by adjusting the opening. In addition, the third expansion valve 13c located upstream of the refrigerant circulation path relative to the heat storage heat exchanger 16 and the second expansion valve 13b located downstream adjust the heat storage temperature (pressure) and the flow rate of the refrigerant by adjusting their respective openings.

[0058] Here, when switching from the heat storage / heating operation (S1) to the defrosting / heating operation (S3), the air conditioner 1 first switches the heat storage heat exchanger 16 as an evaporator. As a result, in the air conditioner 1, the refrigerant circulates in such a manner that the indoor heat exchanger 14 functions as a condenser and the outdoor heat exchanger 15 and the heat storage heat exchanger 16 function as evaporators (S2). Next, the air conditioner 1 switches the outdoor heat exchanger 15 as a condenser and enters the defrosting / heating operation state (S3). By switching in this way, the air conditioner 1 will always maintain a circulation path in which the refrigerant discharged from the compressor 11 circulates through the condenser and evaporator and then returns to the compressor 11.

[0059] In the defrosting / heating operation (S3), the air conditioner 1 circulates the refrigerant so that the indoor heat exchanger 14 and the outdoor heat exchanger 15 function as condensers and the heat storage heat exchanger 16 functions as an evaporator. Here, the first expansion valve 13a adjusts the condensing temperature by adjusting the opening degree.

[0060] In addition, the third expansion valve 13c located upstream of the refrigerant circulation path relative to the outdoor heat exchanger 15 adjusts the flow rate (defrost flow rate) and temperature of the refrigerant flowing to the outdoor heat exchanger 15 by adjusting the opening degree so that the temperature (condensation temperature) of the heat storage heat exchanger 16 detected by the temperature sensor 17e approaches the calculated target condensation temperature. As a result, in the air conditioner 1, it is possible to suppress the supply of excessively high temperature refrigerant to the outdoor heat exchanger 15. In addition, the second expansion valve 13b located upstream of the refrigerant circulation path relative to the heat storage heat exchanger 16 adjusts the overall flow rate of the refrigerant flowing in the refrigerant circuit 10 by adjusting the opening degree.

[0061] In addition, the third expansion valve 13c located upstream of the outdoor heat exchanger 15 in the refrigerant circulation path is opened more during the defrosting and heating operation than during the thermal storage and heating operation ( Figure 5 In the example, it is 32pls→125pls), so the circulation amount of the refrigerant circulating per unit time during the defrosting heating operation will be greater than the circulation amount of the refrigerant circulating per unit time during the thermal storage heating operation.

[0062] In addition, during the defrosting / heating operation, the opening degree ( Figure 5 In the example, 125 pls) is greater than the opening degree of the second expansion valve 13b located upstream of the heat storage heat exchanger 16 ( Figure 5 Thus, in the air conditioner 1, the flow rate of the refrigerant flowing into the outdoor heat exchanger 15 during the defrosting and heating operation can be adjusted to the minimum flow rate required for defrosting, so that the flow rate of the refrigerant supplied to the indoor heat exchanger 14 can be increased. In addition, the flow rate of the refrigerant is adjusted in a manner that does not excessively reduce the temperature of the heat storage heat exchanger 16, so that the defrosting / heating operation can be performed more efficiently.

[0063] Figure 7 1 is an explanatory diagram for explaining the state of the air conditioner during defrosting / heating operation according to the embodiment. Figure 7 As shown, during the defrosting / heating operation, the control device 20 controls the opening degree of the third expansion valve 13 c based on the input of the detection result of the temperature sensor 17 .

[0064] Specifically, the control device 20 fixes the openings of the first expansion valve 13a and the second expansion valve 13b (for example, fully open) during defrosting / heating operation. Next, the control device 20 controls the opening of the expansion valve 13 (for example, increasing the opening of the third expansion valve 13c as the temperature rises) based on the temperature of the outdoor heat exchanger 15 detected by the temperature sensor 17c.

[0065] return Figure 3After S19, the control device 20 determines whether the defrost end condition is satisfied (S20). For example, the control device 20 determines that the defrost end condition is satisfied when the temperature of the outdoor heat exchanger 15 satisfies the prescribed temperature condition (reaches 16°C). In addition, the control device 20 may also determine that the defrost end condition is satisfied when not only the temperature of the outdoor heat exchanger 15 satisfies the prescribed condition but also the duration of the defrost heating operation satisfies the prescribed condition (for example, the continuous operation time is longer than the prescribed time, etc.).

[0066] If the defrosting end condition is not satisfied (S20: No), the control device 20 returns to the process of S19. If the defrosting start condition is satisfied (S20: Yes), the control device 20 performs the processes of S21 to S28 to switch from the defrosting / heating operation to the heat storage / heating operation.

[0067] Specifically, the control device 20 starts the outdoor fan 31 (S21). Then, the control device 20 changes the third expansion valve 13c to the post-defrosting pulse (f) (S22). The post-defrosting pulse (f) is set to a pulse corresponding to an opening that can ensure the working differential pressure of the three-way valve 12b and does not cause an excessive flow rate of the refrigerant flowing to the heat storage heat exchanger 16. As a result, the third expansion valve 13c is adjusted to the opening after defrosting.

[0068] Next, the control device 20 switches the second three-way valve 12b so that the flow paths 10d and 10b are connected, and the outdoor heat exchanger 15 functions as an evaporator (S23). Next, the control device 20 changes the second expansion valve 13b to the post-defrost pulse (g) (S24). The post-defrost pulse (g) is set to a pulse corresponding to an opening that can prevent liquid from accumulating in the heat storage heat exchanger 16 and does not cause an excessive flow rate of the refrigerant flowing to the heat storage heat exchanger 16. Thus, the second expansion valve 13b is adjusted to the opening after defrosting.

[0069] Next, the control device 20 switches the third three-way valve 12c to connect the flow paths 10a and 10e, and allows the heat storage heat exchanger 16 to function as a condenser (S25). Next, the control device 20 releases the fixed opening of the first expansion valve 13a and starts the discharge temperature control operation (S26).

[0070] Next, the control device 20 switches the indoor fan 32 to the air volume designated by the user set by remote control operation or the like, and switches the compressor 11 to a rotation speed that matches the required capacity as the heating capacity ( S27 ).

[0071] Then, similarly to S12, the control device 20 controls (adjusts) the opening degrees of the second expansion valve 13b and the third expansion valve 13c using the control value calculated based on the detection result of the temperature sensor 17 (S28).

[0072] Figure 8 1 is an example of a timing chart when the air conditioner 1 according to the embodiment is released from defrosting operation. Figure 8 As shown, after the defrosting / heating operation is released, the air conditioner 1 starts the outdoor fan 31 at time t11.

[0073] Next, at time t12, the air conditioner 1 changes the third expansion valve 13c to the post-defrost pulse (f) (125 pls → 32 pls in the example shown). Next, at time t13, the air conditioner 1 switches the second three-way valve 12b to change the outdoor heat exchanger 15 from a condenser (heat release, defrosting) to an evaporator (heat absorption). Next, at time t14, the air conditioner 1 switches the third three-way valve 12c to change the heat storage heat exchanger 16 from an evaporator (heat release) to a condenser (heat storage).

[0074] Next, at time t15, in the air conditioner 1, the opening fixation of the first expansion valve 13a is released, and the discharge temperature control operation implemented by adjusting the opening of the first expansion valve 13a is started. Next, at time t16, the air volume of the indoor fan 32 in the air conditioner 1 is switched to the air volume (Hi wind) specified by the user. Next, at time t17, the air conditioner 1 starts automatic control (speed control) of the compressor 11 in accordance with the required capacity as the heating capacity.

[0075] like Figure 6 As shown, in the defrosting / heating operation ( S3 ), the air conditioner 1 circulates the refrigerant so that the indoor heat exchanger 14 and the outdoor heat exchanger 15 function as condensers and the heat storage heat exchanger 16 functions as an evaporator.

[0076] Here, when switching from the defrosting / heating operation (S3) to the heat storage / heating operation (S5), the air conditioner 1 first switches the outdoor heat exchanger 15 to serve as an evaporator. Thus, in the air conditioner 1, the refrigerant circulates in such a manner that the indoor heat exchanger 14 functions as a condenser and the outdoor heat exchanger 15 and the heat storage heat exchanger 16 function as evaporators (S4). Next, the air conditioner 1 switches the heat storage heat exchanger 16 to serve as a condenser and enters the heat storage / heating operation state (S5). By switching in this way, the air conditioner 1 will always maintain a circulation path in which the refrigerant discharged from the compressor 11 circulates through the condenser and evaporator and then returns to the compressor 11.

[0077] return Figure 3After S28, the control device 20 determines whether the operation end condition is satisfied, such as whether there is an operation end instruction issued by a user operation, etc. (S29). If the operation end condition is not satisfied (S29: No), the control device 20 returns to the processing of S13. If the operation end condition is satisfied (S29: Yes), the control device 20 ends the processing after executing the end action (switching the three-way valve 12, adjusting the opening of the expansion valve 13, stopping the outdoor fan 31 and the indoor fan 32, etc.) to change to the state at the end of the operation.

[0078] The above is a description of the embodiments of the air conditioner, but the embodiments are not limited to the above contents. In addition, the above components include components that are easily conceivable by a person skilled in the art, are substantially the same, and are within the so-called equivalent range. Furthermore, the above components can be appropriately combined. Furthermore, within the scope of the gist of the embodiments, at least one of various omissions, replacements, and changes to the components can be performed.

[0079] As described above, the air conditioner 1 is connected to a refrigerant circuit 10 for circulating a refrigerant: a compressor 11, an indoor heat exchanger 14, an outdoor heat exchanger 15, a heat storage heat exchanger 16, a plurality of expansion valves 13, and a plurality of three-way valves 12. The compressor 11 is used to compress the refrigerant. The indoor heat exchanger 14 is used to exchange heat between indoor air and the refrigerant. The outdoor heat exchanger 15 is used to exchange heat between outdoor air and the refrigerant. The heat storage heat exchanger 16 is used to exchange heat between a heat storage material 16a and the refrigerant. The plurality of expansion valves 13 are valves that can adjust the opening degree. The plurality of three-way valves 12 are used to switch the circulation path of the refrigerant in the refrigerant circuit 10 between the heat storage heating operation and the defrosting heating operation. The heat storage heating operation makes the indoor heat exchanger 14 and the heat storage heat exchanger 16 function as a condenser and the outdoor heat exchanger 15 function as an evaporator. The defrosting heating operation makes the indoor heat exchanger 14 and the outdoor heat exchanger 15 function as a condenser and the heat storage heat exchanger 16 function as an evaporator. In the air conditioner 1, one of the plurality of expansion valves 13 (the third expansion valve 13c, 13ca) is provided upstream of the outdoor heat exchanger 15 when the outdoor heat exchanger 15 functions as a condenser. The refrigerant flowing into the outdoor heat exchanger 15 is depressurized by the expansion valve 13.

[0080] In this way, by reducing the pressure of the refrigerant flowing into the outdoor heat exchanger 15, in the air conditioner 1, during the defrosting and heating operation in which the indoor heat exchanger 14 and the outdoor heat exchanger 15 function as a condenser, it is possible to suppress the supply of an excessively high temperature refrigerant to the outdoor heat exchanger 15. For example, during the defrosting and heating operation in which the indoor heat exchanger 14 and the outdoor heat exchanger 15 function as a condenser, if the heating capacity for defrosting is too large, the indoor heating capacity will be reduced relatively. In contrast, in the air conditioner 1, by suppressing the supply of an excessively high temperature refrigerant to the outdoor heat exchanger 15, it is possible to suppress the reduction of the indoor heating capacity during the defrosting and heating operation.

[0081] In the air conditioner 1, the one expansion valve 13 (third expansion valve 13c) is provided upstream of the heat storage heat exchanger 16 when the heat storage heat exchanger 16 functions as a condenser. Thus, in the air conditioner 1, when the outdoor heat exchanger 15 or the heat storage heat exchanger 16 is used as a condenser, there is no need to prepare expansion valves separately, and the refrigerant can be decompressed by the one expansion valve 13 (third expansion valve 13c), thereby reducing costs.

[0082] In the air conditioner 1, the circulation amount of the refrigerant flowing through the above-mentioned one expansion valve 13 (third expansion valve 13c) per unit time is greater than that in the heat storage heating operation during the defrosting heating operation. As a result, the air conditioner 1 can average the heating capacity during the heat storage heating operation and can quickly end the defrosting. For example, in the air conditioner 1, during the heat storage heating operation, the circulation amount of the refrigerant to the heat storage heat exchanger 16 becomes smaller, and heat can be stored without significantly reducing the indoor heating capacity, thereby averaging the heating capacity for the indoor and heat storage material 16a. On the contrary, during the defrosting heating operation, the circulation amount of the refrigerant to the outdoor heat exchanger 15 will become larger, and it can be defrosted quickly.

[0083] In the air conditioner 1, when the defrosting heating operation is started by switching from the heat storage heating operation, the opening degree of the expansion valve 13 (third expansion valve 13c, 13ca) is adjusted after the heat storage heat exchanger 16 is switched from the condenser to the evaporator. Thus, in the air conditioner 1, it is possible to suppress a decrease in heating capacity due to a rapid inflow of refrigerant into the heat storage heat exchanger 16 when the heat storage heat exchanger 16 functions as an evaporator.

[0084] In the air conditioner 1, when the heat storage heating operation is started after switching from the defrosting heating operation, the opening degree of the expansion valve 13 (third expansion valve 13c, 13ca) is adjusted before the function of the heat storage heat exchanger 16 is switched from the evaporator to the condenser. Thus, in the air conditioner 1, it is possible to suppress a decrease in heating capacity due to a rapid inflow of refrigerant into the heat storage heat exchanger 16 when the heat storage heat exchanger 16 functions as a condenser.

[0085] The air conditioner 1 has a temperature sensor 17c for detecting the temperature of the outdoor heat exchanger 15, and the opening degree of the expansion valve 13 (third expansion valve 13c, 13ca) is adjusted based on the temperature detected by the temperature sensor 17c during the defrosting and heating operation. As a result, in the air conditioner 1, the refrigerant pressure of the outdoor heat exchanger 15 during the defrosting and heating operation can be adjusted according to the temperature of the outdoor heat exchanger 15, and defrosting can be performed more efficiently.

[0086] In the air conditioner 1, the flow rate of the refrigerant passing through the above-mentioned one expansion valve 13 (third expansion valve 13c, 13ca) per unit time during the defrosting and heating operation is smaller than the flow rate of the refrigerant passing through the expansion valve 13 (second expansion valve 13b) located upstream of the heat storage heat exchanger 16 among the plurality of expansion valves 13 per unit time. As a result, in the air conditioner 1, it is possible to avoid an excessive increase in the temperature of the outdoor heat exchanger 15 and an excessive decrease in the temperature of the heat storage heat exchanger 16 during the defrosting and heating operation, so that the defrosting and heating operation can be performed more efficiently.

[0087] In the air conditioner 1, during the thermal storage heating operation, the flow rate of the refrigerant passing through the third expansion valves 13c and 13ca located upstream of the thermal storage heat exchanger 16 among the plurality of expansion valves 13 per unit time is greater than the flow rate of the refrigerant passing through the second expansion valve 13b located downstream of the thermal storage heat exchanger 16 per unit time. As a result, in the air conditioner 1, the refrigerant pressure of the thermal storage heat exchanger 16 during the thermal storage heating operation can be increased, the heat storage amount of the thermal storage material 16a can be increased, and the defrosting time can be shortened.

[0088] Explanation of symbols

[0089] 1.1a…Air conditioner

[0090] 10…Refrigerant circuit

[0091] 10a~10f…Flow path

[0092] 11…Compressor

[0093] 12…Three-way valve

[0094] 12a…First three-way valve

[0095] 12b…Second three-way valve

[0096] 12c…Third three-way valve

[0097] 13…Expansion valve

[0098] 13a…First expansion valve

[0099] 13b…Second expansion valve

[0100] 13c, 13ca…third expansion valve

[0101] 13cb…Fourth expansion valve

[0102] 14…Indoor heat exchanger

[0103] 15…Outdoor heat exchanger

[0104] 16…Heat storage heat exchanger

[0105] 16a…Heat storage material

[0106] 17, 17a~17f…temperature sensor

[0107] 20…Control device

[0108] 21… Storage device

[0109] 22…CPU

[0110] 31…Outdoor fan

[0111] 32…Indoor fan

[0112] t1~t8、t11~t17…time

Claims

1. An air conditioner, characterized in that: Connected to the refrigerant circuit for circulating the refrigerant are: A compressor for compressing the refrigerant; An indoor heat exchanger, which is used to exchange 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, which is used to exchange heat between the heat storage material and the refrigerant; A plurality of expansion valves, the opening of which can be adjusted; as well as a plurality of switching valves for switching a circulation path of the refrigerant in the refrigerant circuit between a heat storage heating operation and a defrosting heating operation, wherein the heat storage heating operation causes the indoor heat exchanger and the heat storage heat exchanger to function as a condenser and the outdoor heat exchanger to function as an evaporator, and the defrosting heating operation causes the indoor heat exchanger and the outdoor heat exchanger to function as a condenser and the heat storage heat exchanger to function as an evaporator, One of the plurality of expansion valves is provided upstream of the outdoor heat exchanger when the outdoor heat exchanger functions as a condenser, and the refrigerant flowing into the outdoor heat exchanger is decompressed by the one expansion valve.

2. The air conditioner according to claim 1, characterized in that: The one expansion valve is provided upstream of the thermal storage heat exchanger when the thermal storage heat exchanger functions as a condenser.

3. The air conditioner according to claim 2, characterized in that: The flow rate of the refrigerant flowing through the one expansion valve per unit time is greater during the defrosting and heating operation than during the thermal storage and heating operation.

4. The air conditioner according to claim 1, characterized in that: When the defrosting heating operation is started after the thermal storage heating operation is switched, the opening degree of the one expansion valve is adjusted after the thermal storage heat exchanger is switched from the condenser to the evaporator.

5. The air conditioner according to claim 1, characterized in that: When the thermal storage heating operation is started after the defrosting and heating operation is switched, the opening degree of the one expansion valve is adjusted before the function of the thermal storage heat exchanger is switched from the evaporator to the condenser.

6. The air conditioner according to claim 1, characterized in that: A temperature detection unit is provided for detecting the temperature of the outdoor heat exchanger. During the defrosting and heating operation, the opening degree of the one expansion valve is adjusted based on the temperature detected by the temperature detection unit.

7. The air conditioner according to claim 1, characterized in that: During the defrosting and heating operation, a flow rate of the refrigerant passing through the one expansion valve per unit time is made smaller than a flow rate of the refrigerant passing through an expansion valve located upstream of the heat storage heat exchanger among the plurality of expansion valves per unit time.

8. The air conditioner according to claim 1, characterized in that: During the thermal storage heating operation, a flow rate of refrigerant passing through an expansion valve located upstream of the thermal storage heat exchanger among the plurality of expansion valves per unit time is made larger than a flow rate of refrigerant passing through an expansion valve located downstream of the thermal storage heat exchanger per unit time.

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