Air conditioner

Abstract

Provided is an air conditioner capable of suppressing a temperature drop in a room during a defrosting operation. An air conditioner according to one embodiment has an indoor heat exchanger, an outdoor heat exchanger, a first pipe, a second pipe, a compressor, a pressure reducer, a bypass pipe, a valve, and a first heat storage material. The compressor is provided in the first pipe and has a suction port and a discharge port. The pressure reducer is provided in the second pipe. The bypass pipe has a first end portion connected to the first pipe between the indoor heat exchanger and the discharge port, and a second end portion connected to the second pipe between the outdoor heat exchanger and the pressure reducer. The valve is provided in the bypass pipe and capable of cutting off the flow of refrigerant. The first heat storage material is thermally connected to the first pipe between the outdoor heat exchanger and the suction port, and thermally connected to the bypass pipe between the first end portion and the valve.

Description

Technical Field

[0001] Embodiments of the present invention relate to air conditioners. Background Technology

[0002] Air conditioners, like air conditioners, regulate indoor temperature by condensing and evaporating refrigerant in a refrigeration cycle. For example, during heating operation, the refrigerant condenses in the indoor heat exchanger and evaporates in the outdoor heat exchanger.

[0003] During heating operation, frost may adhere to the outdoor heat exchanger, hindering heat exchange. Air conditioners perform various defrosting operations to remove this frost. For example, in reverse defrosting operation, the air conditioner temporarily operates in cooling mode, using the outdoor heat exchanger as an evaporator to remove the frost.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-047955 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In reverse defrosting operation, the indoor temperature may drop because the indoor heat exchanger becomes a condenser.

[0009] One example of the problem solved by the present invention is to provide an air conditioner that can suppress the drop in indoor temperature during defrosting operation.

[0010] Methods used to solve problems

[0011] An air conditioning apparatus according to an embodiment of the present application has an indoor heat exchanger, an outdoor heat exchanger, a first pipe, a second pipe, a compressor, a pressure reducer, a bypass pipe, a valve, a first heat storage material, and a control device. The first pipe connects the outdoor heat exchanger and the indoor heat exchanger and allows a refrigerant to flow therethrough. The second pipe connects the indoor heat exchanger and the outdoor heat exchanger and allows the refrigerant to flow therethrough. The compressor is provided in the first pipe and has a suction port that sucks the refrigerant and a discharge port that discharges the refrigerant. The pressure reducer is provided in the second pipe. The bypass pipe has a first end portion that is connected to the first pipe between the indoor heat exchanger and the discharge port and a second end portion that is connected to the second pipe between the outdoor heat exchanger and the pressure reducer and allows the refrigerant to flow therethrough. The valve is provided in the bypass pipe and is capable of switching between a first state in which the refrigerant is allowed to flow in the bypass pipe between the first end portion and the second end portion and a second state in which the flow of the refrigerant between the first end portion and the second end portion in the bypass pipe is cut off. The first heat storage material is thermally connected to the first pipe between the outdoor heat exchanger and the suction port and thermally connected to the bypass pipe between the first end portion and the valve. The control device controls the valve.

[0012] The air conditioning apparatus further has a second heat storage material that is thermally connected to the second pipe between the indoor heat exchanger and the pressure reducer and thermally connected to the bypass pipe between the second end portion and the valve.

[0013] For the air conditioning apparatus, the control device sets the valve to the second state during a heating operation and sets the valve to the first state during a defrosting operation.

[0014] The air conditioning apparatus further has an indoor blower fan that generates an airflow that exchanges heat with the indoor heat exchanger. The control device controls the indoor blower fan to have a rotational speed that is lower than a maximum rotational speed of the indoor blower fan during the heating operation during the defrosting operation.

[0015] The air conditioning apparatus further has an outdoor blower fan that generates an airflow that exchanges heat with the outdoor heat exchanger. The control device controls the outdoor blower fan to be stopped during the defrosting operation.

[0016] According to the above air conditioning apparatus, for example, a temperature drop in a room can be suppressed during a defrosting operation. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1is a schematic refrigerant system diagram of the air conditioner during the heating operation of one embodiment.

[0018] Figure 2 is a schematic refrigerant system diagram of the air conditioner during the cooling operation of the above embodiment.

[0019] Figure 3 is a block diagram functionally showing the structure of the air conditioner of the above embodiment.

[0020] Figure 4 is a flowchart showing an example of the defrost operation control of the air conditioner of the above embodiment.

[0021] Figure 5 is a schematic refrigerant system diagram of the air conditioner during the defrost operation of the above embodiment.

[0022] Figure 6 is a block diagram showing an example of the hardware structure of the control device of the above embodiment.

[0023] Explanation of Reference Signs

[0024] 10 air conditioner; 14 control device; 21 outdoor heat exchanger; 22 outdoor blow fan; 23 compressor; 23a suction port; 23b discharge port; 26 pressure reducer; 31 indoor heat exchanger; 32 indoor blow fan; 41 first pipe; 42 second pipe; 51 bypass pipe; 51a first end portion; 51b second end portion; 52 defrosting valve; 53 first heat storage material; 54 second heat storage material. DETAILED DESCRIPTION

[0025] Hereinafter, the above embodiment will be described with reference to Figures 1 to 6 One embodiment will be described. In addition, in the present specification, there are cases where a plurality of expressions are used to describe a constituent element of the embodiment and the explanation of the element. The constituent element and the explanation thereof are one example, and are not limited by the expressions in the present specification. The constituent element can be determined by a name different from the constituent element in the present specification. Furthermore, the constituent element can be explained by an expression different from the expression in the present specification.

[0026] Figure 1 is a schematic refrigerant system diagram of the air conditioner 10 during the heating operation of one embodiment. The air conditioner 10 is, for example, a home air conditioner. In addition, the air conditioner 10 is not limited to this example, and can be another air conditioner such as an office air conditioner.

[0027] As shown in FIG. 1, the air conditioner 10 includes an outdoor unit 20 and an indoor unit 30. The outdoor unit 20 includes an outdoor heat exchanger 21, an outdoor blow fan 22, a compressor 23, a pressure reducer 26, and a control device 14. The indoor unit 30 includes an indoor heat exchanger 31 and an indoor blow fan 32. Figure 1As shown, the air conditioner 10 includes an outdoor unit 11, an indoor unit 12, refrigerant piping 13, and a control unit 14. The outdoor unit 11 is, for example, located outdoors. The indoor unit 12 is, for example, located indoors.

[0028] The air conditioner 10 has a refrigeration cycle that connects an outdoor unit 11 and an indoor unit 12 via a refrigerant piping 13. Refrigerant flows through the refrigerant piping 13 between the outdoor unit 11 and the indoor unit 12. Furthermore, the outdoor unit 11 and the indoor unit 12 are electrically connected to each other, for example, via electrical wiring.

[0029] The outdoor unit 11 includes an outdoor heat exchanger 21, an outdoor fan 22, a compressor 23, a liquid accumulator 24, a four-way valve 25, a pressure reducer 26, and an inverter circuit 27. The indoor unit 12 includes an indoor heat exchanger 31 and an indoor fan 32.

[0030] The refrigerant piping 13 is made of a metal such as copper or aluminum. The refrigerant piping 13 has a first piping 41 and a second piping 42. The first piping 41 connects the outdoor heat exchanger 21 to the indoor heat exchanger 31. The compressor 23, the accumulator 24, and the four-way valve 25 are located on the first piping 41. The second piping 42 connects the indoor heat exchanger 31 to the outdoor heat exchanger 21. A pressure reducer 26 is located on the second piping 42.

[0031] During heating operation, the refrigerant flows from the outdoor heat exchanger 21 to the indoor heat exchanger 31 through the first piping 41, and from the indoor heat exchanger 31 to the outdoor heat exchanger 21 through the second piping 42. Figure 1 The arrows indicate the flow of refrigerant during heating operation.

[0032] Figure 2 This is a schematic diagram of the refrigerant system of the air conditioner 10 during refrigeration operation according to this embodiment. (Example) Figure 2 As shown, during refrigeration operation, the refrigerant flows from the outdoor heat exchanger 21 to the indoor heat exchanger 31 through the second piping 42, and from the indoor heat exchanger 31 to the outdoor heat exchanger 21 through the first piping 41. Figure 2 The arrow indicates the flow of refrigerant during refrigeration operation.

[0033] The outdoor heat exchanger 21 of the outdoor unit 11 acts as an evaporator to absorb heat from the refrigerant, or as a condenser to dissipate heat from the refrigerant, depending on the direction of refrigerant flow. The outdoor fan 22 directs airflow towards the outdoor heat exchanger 21, promoting heat exchange between the refrigerant and the air within the outdoor heat exchanger 21. In other words, the outdoor fan 22 generates airflow that exchanges heat with the outdoor heat exchanger 21.

[0034] The outdoor heat exchanger 21 is, for example, a so-called microchannel heat exchanger having a flat, porous tube with multiple tiny refrigerant flow paths formed inside as a heat pipe. The outdoor heat exchanger 21 can be a so-called cross-fin heat exchanger having multiple plate-shaped heat-conducting fins and heat-conducting tubes connecting the heat-conducting fins, or other types of heat exchangers.

[0035] The compressor 23 has a suction port 23a and a discharge port 23b. The compressor 23 draws in refrigerant through the suction port 23a and discharges the compressed refrigerant through the discharge port 23b. Thus, the compressor 23 compresses the refrigerant in the refrigeration cycle and generates a refrigerant circulation. The operating frequency of the compressor 23 can be changed, for example, by controlling it with an inverter.

[0036] The accumulator 24 is connected to the suction port 23a of the compressor 23. The accumulator 24 separates the gaseous refrigerant from the liquid refrigerant. As a result, the compressor 23 can draw in the gaseous refrigerant that has passed through the accumulator 24 through the suction port 23a.

[0037] The four-way valve 25 is connected to the outdoor heat exchanger 21, the indoor heat exchanger 31, the nozzle 23b of the compressor 23, and the accumulator 24. During heating and cooling operation, the four-way valve 25 switches the flow path connected to the outdoor heat exchanger 21, the indoor heat exchanger 31, the nozzle 23b of the compressor 23, and the accumulator 24 respectively, changing the direction of refrigerant flow.

[0038] like Figure 1 As shown, during heating operation, the four-way valve 25 connects the outdoor heat exchanger 21 to the accumulator 24. Furthermore, during heating operation, the four-way valve 25 connects the indoor heat exchanger 31 to the nozzle 23b of the compressor 23. Thus, the refrigerant compressed by the compressor 23 flows to the indoor heat exchanger 31, and the refrigerant evaporated in the outdoor heat exchanger 21 flows to the accumulator 24.

[0039] like Figure 2 As shown, during cooling operation, the four-way valve 25 connects the outdoor heat exchanger 21 to the nozzle 23b of the compressor 23. Furthermore, during cooling operation, the four-way valve 25 connects the indoor heat exchanger 31 to the accumulator 24. Thus, the refrigerant compressed by the compressor 23 flows to the outdoor heat exchanger 21, and the refrigerant evaporated in the indoor heat exchanger 31 flows to the accumulator 24.

[0040] Pressure regulator 26 is, for example, an electromagnetic expansion valve. Alternatively, pressure regulator 26 can be other types of pressure regulators. For example, the opening degree of the electromagnetic expansion valve 26, which is a pressure regulator, is controlled according to the temperature or pressure of the suction port 23a of the compressor 23, thereby regulating the amount of refrigerant passing through.

[0041] The inverter circuit 27 performs inverter control on the compressor 23, and changes the operation frequency of the compressor 23. The inverter circuit 27 is, for example, an inverter circuit of a PAM (Pulse Amplitude Modulation) system. Note that the inverter circuit 27 is not limited to this example.

[0042] The indoor heat exchanger 31 of the indoor unit 12 is, for example, a so-called cross fin heat exchanger having a plurality of plate-like heat conducting fins and heat conducting pipes that pass through the respective heat conducting fins. The indoor heat exchanger 31 can also be another kind of heat exchanger. The indoor heat exchanger 31, depending on the direction in which the refrigerant flows, absorbs heat as an evaporator or releases heat as a condenser.

[0043] The indoor blower fan 32 blows air toward the indoor heat exchanger 31, and promotes heat exchange between the indoor heat exchanger 31 and the air. In other words, the indoor blower fan 32 generates an airflow that exchanges heat with the indoor heat exchanger 31.

[0044] In the air conditioning device 10 configured as described above, the first pipe 41 has a first region 41a, a second region 41b, a third region 41c, and a fourth region 41d. The first region 41a is a portion of the first pipe 41 between the outdoor heat exchanger 21 and the four-way valve 25. The second region 41b is a portion of the first pipe 41 between the four-way valve 25 and the accumulator 24. The third region 41c is a portion of the first pipe 41 between the discharge port 23b of the compressor 23 and the four-way valve 25. The fourth region 41d is a portion of the first pipe 41 between the four-way valve 25 and the indoor heat exchanger 31.

[0045] The second pipe 42 has a fifth region 42a and a sixth region 42b. The fifth region 42a is a portion of the second pipe 42 between the indoor heat exchanger 31 and the pressure reducer 26. The sixth region 42b is a portion of the second pipe 42 between the pressure reducer 26 and the outdoor heat exchanger 21.

[0046] The outdoor unit 11 of the present embodiment also has a bypass pipe 51, a defrosting valve 52, a first heat storage material 53, a second heat storage material 54, and a temperature sensor 55. The defrosting valve 52 is an example of a valve.

[0047] The bypass pipe 51 is a bypass passage that allows the refrigerant to flow between the first pipe 41 and the second pipe 42. The bypass pipe 51 is included in the refrigerant pipe 13. Therefore, the bypass pipe 51 is a pipe made of metal such as copper or aluminum. The refrigerant can flow through the bypass pipe 51 in the bypass pipe 51.

[0048] The bypass pipe 51 has a first end portion 51a and a second end portion 51b. The first end portion 51a is connected to the first pipe 41 between the indoor heat exchanger 31 and the injection port 23b of the compressor 23. In other words, the first end portion 51a is connected to the fourth region 41d of the first pipe 41. The second end portion 51b is connected to the second pipe 42 between the outdoor heat exchanger 21 and the pressure reducer 26. In other words, the second end portion 51b is connected to the sixth region 42b of the second pipe 42. In addition, the bypass pipe 51 is not limited to a pipe connecting two points, but can be a branched pipe connecting three or more points.

[0049] The defrosting valve 52 is, for example, a solenoid valve. In addition, the defrosting valve 52 can be another valve. The defrosting valve 52 is provided to the bypass pipe 51 at a position away from the first end portion 51a and the second end portion 51b. In addition, the defrosting valve 52 can be located near the first end portion 51a or the second end portion 51b.

[0050] The defrosting valve 52 can be switched to an open state and a closed state according to control. The open state is an example of the first state. The closed state is an example of the second state. The open-state defrosting valve 52 is open, allowing refrigerant to flow in the bypass pipe 51 between the first end portion 51a and the second end portion 51b. The closed-state defrosting valve 52 is closed, cutting off the flow of refrigerant between the first end portion 51a and the second end portion 51b in the bypass pipe 51.

[0051] The defrosting valve 52 can be able to open and close only, or can be able to adjust the flow rate of refrigerant in stages or continuously. In other words, the defrosting valve 52 adjusts the amount of refrigerant flowing in the bypass pipe 51.

[0052] The defrosting valve 52 of the present embodiment is a two-way valve. However, the defrosting valve 52 can be another valve such as a three-way valve. For example, in the case where the defrosting valve 52 is a three-way valve, the defrosting valve 52 can allow refrigerant to flow through a part of the bypass pipe 51 while cutting off the flow of refrigerant between the first end portion 51a and the second end portion 51b in the bypass pipe 51. For example, in the case where the branched bypass pipe 51 has a third end portion connected at a prescribed position of the first pipe 41, the defrosting valve 52 can allow refrigerant to flow in the bypass pipe 51 between the first end portion 51a and the third end portion, cutting off the flow of refrigerant between the first end portion 51a and the second end portion 51b in the bypass pipe 51.

[0053] The bypass pipe 51 has a seventh region 51c and an eighth region 51d. The seventh region 51c is a part of the bypass pipe 51 between the first end portion 51a and the defrosting valve 52. The eighth region 51d is a part of the bypass pipe 51 between the defrosting valve 52 and the second end portion 51b.

[0054] The first heat storage material 53 and the second heat storage material 54, for example, have latent heat storage materials filled in a block-shaped container. The latent heat storage material is, for example, calcium chloride. The first heat storage material 53 and the second heat storage material 54 can also have other latent heat storage materials. The first heat storage material 53 and the second heat storage material 54 of the present embodiment are, for example, heat storage materials that can be used in a temperature band of about 10°C to about 100°C.

[0055] The first heat storage material 53 and the second heat storage material 54 are not limited to the above-described examples, and can be other heat storage materials such as sensible heat storage materials, or heat storage materials that can be used in other temperature bands. Furthermore, the first heat storage material 53 and the second heat storage material 54 can also be different heat storage materials from each other.

[0056] The first heat storage material 53 is thermally connected to the first pipe 41 between the outdoor heat exchanger 21 and the suction port 23a of the compressor 23. Furthermore, the first heat storage material 53 is thermally connected to the bypass pipe 51 between the first end portion 51a and the defrosting valve 52. In the present embodiment, the first heat storage material 53 is thermally connected to the second region 41b and the seventh region 51c.

[0057] The second region 41b and the seventh region 51c pass through the first heat storage material 53, and are in contact with the latent heat storage material of the first heat storage material 53. Thus, the first heat storage material 53 is thermally connected to the second region 41b and the seventh region 51c. The first heat storage material 53, for example, has a larger amount of heat that can be stored (heat storage capacity) than the second region 41b and the seventh region 51c.

[0058] The second region 41b and the seventh region 51c are formed of metal, and are in close contact with the latent heat storage material of the first heat storage material 53. Thus, heat conduction is easily caused between the second region 41b and the latent heat storage material, and between the seventh region 51c and the latent heat storage material.

[0059] The second heat storage material 54 is thermally connected to the second pipe 42 between the indoor heat exchanger 31 and the pressure reducer 26. Furthermore, the second heat storage material 54 is thermally connected to the bypass pipe 51 between the second end portion 51b and the defrosting valve 52. In the present embodiment, the second heat storage material 54 is thermally connected to the fifth region 42a and the eighth region 51d.

[0060] The fifth region 42a and the eighth region 51d pass through the second heat storage material 54, and are in contact with the latent heat storage material of the second heat storage material 54. Thus, the second heat storage material 54 is thermally connected to the fifth region 42a and the eighth region 51d. The second heat storage material 54, for example, has a larger heat storage capacity than the fifth region 42a and the eighth region 51d.

[0061] The fifth region 42a and the eighth region 51d are formed of metal and are in close contact with the latent heat storage material of the second heat storage material 54. Therefore, heat conduction easily occurs between the fifth region 42a and the latent heat storage material and between the eighth region 51d and the latent heat storage material.

[0062] The second heat storage material 54 is also thermally connected to the elements of the inverter circuit 27. For example, the second heat storage material 54 and the elements of the inverter circuit 27 are thermally connected to each other via a member having high thermal conductivity such as metal or a heat conduction sheet. In addition, the second heat storage material 54 can be located away from the inverter circuit 27.

[0063] The temperature sensor 55 is provided to the outdoor heat exchanger 21. The temperature sensor 55 detects the temperature of the refrigerant flowing in the outdoor heat exchanger 21. For example, the temperature sensor 55 is disposed at a position at which the saturation temperature of the refrigerant flowing in the outdoor heat exchanger 21 can be obtained.

[0064] The control device 14 has, for example, an outdoor control device 61 and an indoor control device 62. The outdoor control device 61 and the indoor control device 62 are electrically connected to each other via an electric wiring. At least one of the outdoor control device 61 and the indoor control device 62 is, for example, a computer having a control device such as a CPU (Central Processing Unit) or a microcontroller, a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory. In addition, the control device 14 is not limited to this example. For example, the control device 14 can have only one of the outdoor control device 61 and the indoor control device 62.

[0065] The outdoor control device 61 controls the outdoor blow fan 22, the compressor 23, the four-way valve 25, the pressure reducer 26, the inverter circuit 27, and the defrosting valve 52 of the outdoor unit 11. The indoor control device 62 controls the indoor blow fan 32 of the indoor unit 12. The control device 14 controls the outdoor unit 11 and the indoor unit 12, whereby the air conditioning apparatus 10 performs a cooling operation, a heating operation, a dehumidifying operation, a defrosting operation, and other operations. The indoor control device 62 can input a signal from a remote controller, for example, or can input a signal from an information terminal such as a smartphone via a communication device.

[0066] Figure 3 is a block diagram functionally showing the structure of the air conditioning apparatus 10 of the present embodiment. As shown in Figure 3 The air conditioning apparatus 10 of the present embodiment also has an outdoor fan drive circuit 71, an indoor fan drive circuit 72, and a valve drive circuit 73.

[0067] The outdoor fan drive circuit 71 is a drive circuit of the outdoor air-sending fan 22. The indoor fan drive circuit 72 is a drive circuit of the indoor air-sending fan 32. The valve drive circuit 73 is a drive circuit of the defrosting valve 52.

[0068] The control device 14 is connected to the inverter circuit 27, the temperature sensor 55, the outdoor fan drive circuit 71, the indoor fan drive circuit 72, and the valve drive circuit 73. The control device 14 has a temperature acquisition section 81, an operation switching section 82, an outdoor fan control section 83, an indoor fan control section 84, a compressor control section 85, and a valve control section 86.

[0069] The temperature acquisition section 81 acquires the temperature of the refrigerant flowing in the outdoor heat exchanger 21 using the temperature sensor 55. For example, the temperature acquisition section 81 calculates the temperature of the refrigerant flowing in the outdoor heat exchanger 21 from the output signal of the temperature sensor 55. The operation switching section 82 switches the cooling operation, the heating operation, the dehumidifying operation, and the defrosting operation of the air-conditioner 10.

[0070] The outdoor fan control section 83 controls the outdoor air-sending fan 22. For example, the outdoor fan control section 83 controls the rotation speed of the motor of the outdoor air-sending fan 22 by controlling the outdoor fan drive circuit 71.

[0071] The indoor fan control section 84 controls the indoor air-sending fan 32. For example, the indoor fan control section 84 controls the rotation speed of the motor of the indoor air-sending fan 32 by controlling the indoor fan drive circuit 72.

[0072] The compressor control section 85 controls the compressor 23. For example, the compressor control section 85 controls the operation frequency of the compressor 23 by controlling the inverter circuit 27, thereby controlling the compressor 23 by the inverter.

[0073] The valve control section 86 controls the defrosting valve 52. For example, the valve control section 86 controls the actuator of the defrosting valve 52 by controlling the valve drive circuit 73, thereby switching the defrosting valve 52 between the open state and the closed state.

[0074] With the above-described air-conditioner 10, the outdoor heat exchanger 21 absorbs heat of the refrigerant as an evaporator during the heating operation, and becomes low temperature. Therefore, sometimes the moisture in the air condenses on the outer surface of the outdoor heat exchanger 21, and adheres to the outdoor heat exchanger 21 as frost. The air-conditioner 10 performs the defrosting operation in order to remove the frost adhering to the outdoor heat exchanger 21 during the heating operation.

[0075] Figure 4This is a flowchart illustrating an example of the defrost operation control of the air conditioner 10 according to this embodiment. Hereinafter, an example of the defrost operation control of the air conditioner 10 according to this embodiment will be described. However, the defrost operation control of the air conditioner 10 is not limited to the example described below.

[0076] As described above, the air conditioner 10 performs defrosting operation to remove frost adhering to the outdoor heat exchanger 21 during heating operation. That is, the air conditioner 10 switches from heating operation to defrosting operation. In the following control, the defrosting valve 52 is opened and closed, but during the initial heating operation, the defrosting valve 52 is closed. In addition, the defrosting valve 52 is also closed during cooling operation.

[0077] like Figure 4 As shown, firstly, for example, the operation switching unit 82 determines whether the air conditioner 10 is in heating operation (S101). If the air conditioner 10 is in heating operation (S101: "Yes"), the temperature acquisition unit 81 determines whether a predetermined time has elapsed since the first reference time (S102). The first reference time is, for example, the time when the heating operation started, or the time when the determination in S102 was last performed.

[0078] In S102, if no predetermined time has elapsed since the first reference time (S102: "No"), the system returns to S101 and the switching unit 82 performs the determination again. In S102, if a predetermined time has elapsed since the first reference time (S102: "Yes"), the temperature acquisition unit 81 uses the temperature sensor 55 to detect the temperature (evaporation temperature) of the refrigerant flowing in the outdoor heat exchanger 21 (S103).

[0079] Next, the operation switching unit 82 determines whether the evaporation temperature is below the threshold Ts (S104). The threshold Ts is, for example, the evaporation temperature at which frost adheres to the outer surface of the outdoor heat exchanger 21. However, the threshold Ts is not limited to this example. The threshold Ts can be preset or calculated by the operation switching unit 82. If the evaporation temperature is higher than the threshold Ts (S104: "No"), the process returns to S101, and the operation switching unit 82 performs the determination again.

[0080] If frost adheres to the outer surface of the outdoor heat exchanger 21, it hinders the heat exchange between the airflow generated by the outdoor fan 22 and the refrigerant passing through the outdoor heat exchanger 21, causing the evaporation temperature to drop. In S104, if the evaporation temperature is below the threshold Ts (S104: "Yes"), the operation switching unit 82 causes the air conditioner 10 to start defrosting operation (S105).

[0081] During the defrost operation, first, the compressor control section 85 controls the inverter circuit 27, thereby causing the operation frequency of the compressor 23 to further increase than the operation frequency during the heating operation. Next, the valve control section 86 causes the defrosting valve 52 to be in the open state.

[0082] Figure 5 is a refrigerant system diagram of the air conditioning apparatus 10 during the defrost operation of the present embodiment. As shown in Figure 5 If the defrosting valve 52 is in the open state, the refrigerant of the 4th region 41d can flow to the 6th region 42b through the bypass pipe 51. Therefore, the high-temperature and high-pressure gaseous refrigerant (hot gas) ejected from the ejection port 23b of the compressor 23 flows into the outdoor heat exchanger 21 through the bypass pipe 51. As the hot gas passes through the outdoor heat exchanger 21, the temperature of the outdoor heat exchanger 21 increases. Thus, the frost adhering to the outdoor heat exchanger 21 melts and is removed.

[0083] Further, during the defrost operation, the outdoor fan control section 83 stops the outdoor blow fan 22. Normally, if the outdoor blow fan 22 rotates, the air current generated by the outdoor blow fan 22 cools the outdoor heat exchanger 21. In the present embodiment, since the outdoor blow fan 22 is stopped, the temperature of the outdoor heat exchanger 21 easily increases, and the frost adhering to the outdoor heat exchanger 21 easily melts.

[0084] Further, during the defrost operation, the indoor fan control section 84 sets the rotation speed of the indoor blow fan 32 to be lower than the maximum rotation speed of the indoor blow fan during the heating operation. For example, during the heating operation, the indoor fan control section 84 sets the rotation speed of the indoor blow fan 32 between 0 (stop) and high speed in accordance with the temperature of the indoor and the setting by the user. On the other hand, during the defrost operation, the indoor fan control section 84 sets the rotation speed of the indoor blow fan 32 between 0 (stop) and low speed. That is, the indoor fan control section 84 stops the indoor blow fan 32 or causes it to rotate at low speed during the defrost operation.

[0085] As described above, during the defrost operation, the defrosting valve 52 is opened, the outdoor blow fan 22 is stopped, and the indoor blow fan 32 is stopped or rotates at low speed. In addition, the defrost operation is not limited to this example. For example, during the defrost operation, the valve provided between the 1st end portion 51a of the bypass pipe 51 and the indoor heat exchanger 31 can also be closed.

[0086] Next, the temperature acquisition section 81 determines whether or not a predetermined time has elapsed from the 2nd reference time (S106). The 2nd reference time is, for example, the time when the determination of S102 of the last time is performed, or the time when the determination of S106 of the last time is performed.

[0087] In S106, if no predetermined time has elapsed since the second reference time (S106: "No"), the temperature acquisition unit 81 stands still until the predetermined time has elapsed since the second reference time. In S106, if the predetermined time has elapsed since the second reference time (S106: "Yes"), the temperature acquisition unit 81 uses the temperature sensor 55 to detect the evaporation temperature (S107).

[0088] Next, the operation switching unit 82 determines whether the evaporation temperature is higher than the threshold Ts (S108). If the evaporation temperature is lower than the threshold Ts (S108: "No"), the process returns to S106, and the temperature acquisition unit 81 makes the determination again.

[0089] In S108, if the evaporation temperature is higher than the threshold Ts (S108: "Yes"), the operation switching unit 82 causes the air conditioner 10 to stop defrosting operation and start heating operation (S109).

[0090] During heating operation, firstly, the compressor control unit 85 controls the inverter circuit 27 to make the operating frequency of the compressor 23 lower than the operating frequency during defrost operation. Alternatively, during heating operation, the compressor control unit 85 can also set the operating frequency of the compressor 23 to be higher than the operating frequency during defrost operation. Next, the valve control unit 86 sets the defrost valve 52 to the closed state.

[0091] like Figure 1 As shown, if the defrost valve 52 is closed, the refrigerant in zone 41d is restricted from flowing through the bypass pipe 51 to zone 6 42b. Therefore, the refrigerant ejected from the nozzle 23b of the compressor 23 does not flow through the bypass pipe 51, but instead flows through zone 41d into the indoor heat exchanger 31.

[0092] Furthermore, during heating operation, the outdoor fan control unit 83 causes the outdoor air supply fan 22 to rotate, and the indoor fan control unit 84 causes the indoor air supply fan 32 to rotate. The maximum speed of the indoor air supply fan 32 during heating operation is higher than the speed of the indoor air supply fan 32 during defrosting operation.

[0093] As shown above, during heating operation, the defrost valve 52 is closed, the outdoor fan 22 rotates, and the indoor fan 32 rotates. However, heating operation is not limited to this example. The speeds of the outdoor fan 22 and the indoor fan 32 can also be varied according to the indoor temperature and settings made by the user.

[0094] Next, returning to S101, the operation switching unit 82 makes another determination. If the air conditioner 10 switches to cooling operation or dehumidification operation, or if the air conditioner 10 stops operating but does not perform heating operation (S101: "No"), the defrosting operation control ends.

[0095] As described above, during the heating operation, the defrosting valve 52 is in the closed state. Therefore, the refrigerant discharged from the discharge port 23b of the compressor 23 flows into the indoor heat exchanger 31 through the fourth region 41d. However, a part of the refrigerant discharged from the discharge port 23b of the compressor 23 can flow into the seventh region 51c of the bypass pipe 51. Therefore, heat is conducted from the high-temperature refrigerant flowing into the seventh region 51c to the first heat storage material 53 thermally connected to the seventh region 51c, and the first heat storage material 53 stores heat.

[0096] The first heat storage material 53 is thermally connected to the second region 41b of the first pipe 41. Therefore, the first heat storage material 53 stores heat, and gives heat to the low-temperature refrigerant passing through the second region 41b. Thus, the refrigerant of the second region 41b is warmed and pressurized, and flows into the suction port 23a of the compressor 23 through the accumulator 24. Thus, the return of the liquid refrigerant to the compressor 23 is suppressed.

[0097] Further, the refrigerant passing through the indoor heat exchanger 31 flows through the fifth region 42a of the second pipe 42. Therefore, heat is conducted from the medium-temperature refrigerant flowing through the fifth region 42a to the second heat storage material 54 thermally connected to the fifth region 42a, and the second heat storage material 54 stores heat.

[0098] As described above, during the defrosting operation, the defrosting valve 52 is in the open state. Therefore, a part of the refrigerant of the fourth region 41d flows through the bypass pipe 51 to the sixth region 42b. In addition, another part of the refrigerant of the fourth region 41d flows into the indoor heat exchanger 31 as in the heating operation.

[0099] A part of the high-temperature and high-pressure gaseous refrigerant discharged from the discharge port 23b of the compressor 23 flows through the bypass pipe 51. Therefore, in the seventh region 51c, heat is conducted from the refrigerant to the first heat storage material 53. The refrigerant flowing through the bypass pipe 51 flows through the eighth region 51d after the heat is taken away from the refrigerant by the first heat storage material 53 in the seventh region 51c.

[0100] In addition, another part of the high-temperature and high-pressure gaseous refrigerant discharged from the discharge port 23b of the compressor 23 passes through the indoor heat exchanger 31 and flows through the fifth region 42a. Since the indoor blower fan 32 is stopped or is being rotated at a low speed, the temperature of the refrigerant flowing through the fifth region 42a during the defrosting operation is higher than the temperature of the refrigerant flowing through the fifth region 42a during the heating operation. Heat is conducted from the refrigerant flowing through the fifth region 42a to the second heat storage material 54.

[0101] The heat conducted from the refrigerant flowing through the 5th region 42a to the 2nd heat storage material 54 and the heat stored in the 2nd heat storage material 54 is conducted to the refrigerant flowing through the 8th region 51d of the bypass pipe 51. Thus, the refrigerant flowing through the bypass pipe 51 is taken away heat at the 7th region 51c by the 1st heat storage material 53, but is given heat at the 8th region 51d by the 2nd heat storage material 54. The refrigerant (hot gas) warmed up and pressurized by the 2nd heat storage material 54 is merged with the refrigerant after passing through the pressure reducer 26 at the 6th region 42b, and flows into the outdoor heat exchanger 21.

[0102] As described above, the refrigerant flowing through the bypass pipe 51 is taken away heat by the 1st heat storage material 53, but is given heat by the 2nd heat storage material 54. Thus, the refrigerant (hot gas) flowing through the bypass pipe 51 is kept at a high temperature. Since the refrigerant at a high temperature flows through the outdoor heat exchanger 21, the temperature of the outdoor heat exchanger 21 rises, and frost adhering to the outdoor heat exchanger 21 is removed.

[0103] Since the frost is removed by warming up the outdoor heat exchanger 21, the refrigerant flowing through the outdoor heat exchanger 21 is cooled. The refrigerant after passing through the outdoor heat exchanger 21 flows through the 2nd region 41b after flowing through the 1st region 41a of the 1st pipe 41. The heat conducted from the refrigerant flowing through the 7th region 51c to the 1st heat storage material 53 and the heat stored in the 1st heat storage material 53 is conducted to the refrigerant flowing through the 2nd region 41b. Thus, the refrigerant at a low temperature flowing through the 2nd region 41b is warmed up and pressurized, and flows into the suction port 23a of the compressor 23 after passing through the accumulator 24.

[0104] Generally, the lower the temperature and pressure of the refrigerant sucked into the suction port 23a of the compressor 23, the lower the temperature and pressure of the refrigerant ejected from the ejection port 23b of the compressor 23. In the present embodiment, since the refrigerant after passing through the 2nd region 41b is warmed up and pressurized, the temperature and pressure of the refrigerant ejected from the ejection port 23b of the compressor 23 are suppressed from becoming low. Further, the load acting on the compressor 23 is reduced, and the backflow of the refrigerant in a liquid state into the compressor 23 is suppressed.

[0105] As above, during the defrosting operation, the first heat storage material 53 heats the refrigerant sucked into the suction port 23a of the compressor 23. That is, the seventh region 51c, the first heat storage material 53, and the second region 41b function as a heat circuit that heats the refrigerant sucked into the suction port 23a. Further, the second heat storage material 54 re-heats the refrigerant from which the heat has been taken by the first heat storage material 53. That is, the fifth region 42a, the second heat storage material 54, and the eighth region 51d function as a heat circuit that recovers heat from the refrigerant flowing through the fifth region 42a to the refrigerant flowing through the eighth region 51d. Thus, the air conditioner 10 of the present embodiment can suppress a drop in the temperature of the refrigerant supplied to the outdoor heat exchanger 21 during the defrosting operation, and quickly remove the frost adhering to the outdoor heat exchanger 21.

[0106] The defrosting operation is performed for, for example, about 5 minutes. The first heat storage material 53 and the second heat storage material 54 have a heat storage capacity that can give heat to the refrigerant for a period of about 5 minutes. Note that the defrosting operation time and the heat storage capacity of the first heat storage material 53 and the second heat storage material 54 are not limited to this example.

[0107] The air conditioner 10 can also perform the defrosting operation of the reverse mode in which the cooling operation is temporarily performed when the frost adheres to the outdoor heat exchanger 21. However, in the defrosting operation of the reverse mode, since the indoor heat exchanger 31 functions as an evaporator, the indoor air temperature drops, and it takes time until the resumption to the heating operation. In contrast, the defrosting operation of the present embodiment in which the high-temperature refrigerant is supplied to the outdoor heat exchanger 21 through the bypass pipe 51 as described above suppresses the drop in the indoor temperature since the indoor heat exchanger 31 functions as a condenser as in the heating operation, and the time until the resumption to the heating operation is shortened.

[0108] Further, as described above, the elements of the inverter circuit 27 are thermally connected to the second heat storage material 54. During the operation of the air conditioner 10, the temperature of the elements of the inverter circuit 27 becomes higher than the temperature of the refrigerant flowing through the second pipe 42. Thus, the heat of the elements of the inverter circuit 27 is conducted to the second heat storage material 54. In other words, the elements of the inverter circuit 27 are cooled by the second heat storage material 54.

[0109] For the air conditioning apparatus 10 of the above-described embodiment, the bypass pipe 51 has a first end portion 51a connected to the first pipe 41 between the indoor heat exchanger 31 and the discharge port 23b, and a second end portion 51b connected to the second pipe 42 between the outdoor heat exchanger 21 and the pressure reducer 26. The defrosting valve 52 provided in the bypass pipe 51 is switchable between an open state in which the refrigerant is allowed to flow in the bypass pipe 51 between the first end portion 51a and the second end portion 51b, and a closed state in which the flow of the refrigerant between the first end portion 51a and the second end portion 51b in the bypass pipe 51 is blocked. The first heat storage material 53 is thermally connected to the first pipe 41 between the outdoor heat exchanger 21 and the suction port 23a, and is thermally connected to the bypass pipe 51 between the first end portion 51a and the defrosting valve 52. For example, during the heating operation, the high-temperature refrigerant discharged from the discharge port 23b of the compressor 23 flows to the indoor heat exchanger 31 through the first pipe 41, and flows to the portion of the bypass pipe 51 between at least the first end portion 51a and the defrosting valve 52. Thus, heat is transferred from the high-temperature refrigerant flowing into the bypass pipe 51 to the first heat storage material 53, and the first heat storage material 53 is heat-stored. For example, during the defrosting operation, the defrosting valve 52 is opened, and the high-temperature refrigerant discharged from the discharge port 23b of the compressor 23 flows to the outdoor heat exchanger 21 through the bypass pipe 51. As the high-temperature refrigerant passes through the outdoor heat exchanger 21, the frost adhering to the outdoor heat exchanger 21 is melted and removed. The refrigerant is cooled at the outdoor heat exchanger 21, but transfers heat from the heat-stored first heat storage material 53, and is warmed up between the outdoor heat exchanger 21 and the suction port 23a. Thus, the temperature of the refrigerant sucked into the suction port 23a is suppressed from being lowered, and further, the temperature of the refrigerant discharged from the discharge port 23b of the compressor 23 is suppressed from being lowered, and the efficiency of the compressor 23 is also suppressed from being lowered. Thus, the air conditioning apparatus 10 of the present embodiment can quickly remove the frost adhering to the outdoor heat exchanger 21 without temporarily performing the cooling operation as in the reverse-cycle defrosting operation, by keeping the temperature of the refrigerant flowing to the outdoor heat exchanger 21 through the bypass pipe 51 high, and can suppress the decrease in the heating capacity of the air conditioning apparatus 10. Further, the air conditioning apparatus 10 of the present embodiment can suppress the decrease in the temperature of the room, and can speed up the recovery from the defrosting operation to the heating operation, because the cooling operation during the defrosting operation is not required. Furthermore, the air conditioning apparatus 10 of the present embodiment can suppress the increase in cost, because no complicated piping, switching device, and control are required. In addition to the above, during the heating operation, the first heat storage material 53 also transfers heat between the portion of the first pipe 41 between the outdoor heat exchanger 21 and the suction port 23a and the bypass pipe 51. Thus, the refrigerant sucked into the suction port 23a of the compressor 23 is warmed up and pressurized, and the occurrence of the backflow at the compressor 23 is suppressed.

[0110] The second heat storage material 54 is thermally connected to the second pipe 42 between the indoor heat exchanger 31 and the pressure reducer 26, and is thermally connected to the bypass pipe 51 between the second end portion 51b and the defrosting valve 52. For example, in the heating operation, heat is conducted from the refrigerant of medium temperature condensed by the indoor heat exchanger 31 to the second heat storage material 54, and the second heat storage material 54 stores the heat. For example, in the defrosting operation, the refrigerant passing through the bypass pipe 51 is cooled due to heat conduction to the first heat storage material 53, but is heated from the second heat storage material 54 between the defrosting valve 52 and the second end portion 51b. Thus, the air conditioner 10 of the present embodiment can suppress the temperature of the refrigerant flowing into the outdoor heat exchanger 21 from becoming low, and can quickly remove the frost adhering to the outdoor heat exchanger 21.

[0111] The control device 14 sets the defrosting valve 52 to the closed state in the heating operation, and sets the defrosting valve 52 to the open state in the defrosting operation. Thus, the air conditioner 10 of the present embodiment can suppress the refrigerant from passing through the bypass pipe 51 in the heating operation, and can cause all of the high-temperature refrigerant to be condensed in the indoor heat exchanger 31. Further, since the high-temperature refrigerant discharged from the discharge port 23b of the compressor 23 flows into the outdoor heat exchanger 21 through the bypass pipe 51 in the defrosting operation, the air conditioner 10 of the present embodiment can quickly remove the frost adhering to the outdoor heat exchanger 21 without temporarily performing the cooling operation as in the reverse-cycle defrosting operation.

[0112] The indoor supply fan 32 generates an airflow that exchanges heat with the indoor heat exchanger 31. The control device 14 causes the rotational speed of the indoor supply fan 32 to be lower than the maximum rotational speed of the indoor supply fan 32 in the heating operation in the defrosting operation. For example, the control device 14 stops the indoor supply fan 32 or causes the indoor supply fan 32 to rotate at a low speed in the defrosting operation. Thus, the refrigerant is suppressed from being cooled by the indoor heat exchanger 31 in the defrosting operation, and the refrigerant passing through the indoor heat exchanger 31 is suppressed from cooling the refrigerant passing through the bypass pipe 51. Thus, the air conditioner 10 of the present embodiment can quickly remove the frost adhering to the outdoor heat exchanger 21 by keeping the temperature of the refrigerant flowing into the outdoor heat exchanger 21 high in the defrosting operation.

[0113] The outdoor supply fan 22 generates an airflow that exchanges heat with the outdoor heat exchanger 21. The control device 14 stops the outdoor supply fan 22 in the defrosting operation. Thus, the air conditioner 10 of the present embodiment can suppress the airflow from cooling the outdoor heat exchanger 21 in the defrosting operation, and can further quickly remove the frost adhering to the outdoor heat exchanger 21.

[0114] In the above description, the temperature sensor 55 detects the evaporation temperature of the refrigerant flowing in the outdoor heat exchanger 21, and the operation switching section 82 makes the determination based on the evaporation temperature. However, the air conditioning machine 10 of the present embodiment is not limited to this example. For example, the temperature sensor 55 can detect the temperature of the outer surface of the outdoor heat exchanger 21 or the outside air temperature, and the operation switching section 82 can make the determination based on the temperature detected by the temperature sensor 55.

[0115] Figure 6 is a block diagram showing an example of the hardware structure of the control device 14 of the present embodiment. The control device 14 is implemented by, for example, a computer 100 having the hardware structure shown in Figure 6 .

[0116] The computer 100 has, for example, a CPU 101, a ROM 102, a RAM 103, a storage device 104, and an interface (I / F) 106. The CPU 101, the ROM 102, the RAM 103, the storage device 104, and the I / F 106 are connected by a bus.

[0117] The CPU 101 can expand the program stored in the storage device 104 to the RAM 103 and execute it, control each section to perform input and output, or perform processing of data. In the ROM 102, a boot program that reads a program for starting an operating system from the storage device 104 to the RAM 103 is stored.

[0118] The storage device 104 is, for example, a flash memory. The storage device 104 stores an operating system, application programs, and data. These programs are recorded in a file in an installable form or an executable form to a recording medium that can be read by a computer, and distributed. In addition, the programs can be distributed by being downloaded from a server.

[0119] The I / F 106 is, for example, an interface device for connecting with the four-way valve 25, the inverter circuit 27, the temperature sensor 55, the outdoor fan drive circuit 71, the indoor fan drive circuit 72, and the valve drive circuit 73. The I / F 106 is connected with the four-way valve 25, for example, via a drive circuit for driving the four-way valve 25.

[0120] The program executed by the computer 100 of the present embodiment can be provided in a file in an installable form or an executable form to a recording medium that can be read by a computer, such as a CD-ROM, a floppy disk (FD), a CD-R, a DVD, and the like.

[0121] Further, it is also possible to configure such that the program executed by the computer 100 of the present embodiment is saved to a computer connected to a network such as the Internet, and is provided by being downloaded via the network. Further, it is also possible to configure such that the program executed by the computer 100 of the present embodiment is provided or distributed via a network such as the Internet. Further, it is also possible to configure such that the program of the present embodiment is provided by being pre-installed in the ROM 102 or the like.

[0122] The program for causing such a computer 100 to function as the control device 14 is a module structure including a temperature acquisition module, an operation switching module, an outdoor fan control module, an indoor fan control module, a compressor control module, and a valve control module. The computer 100 reads out and executes the program from a storage medium (storage device 104 or the like) by the processor (CPU 101) as actual hardware, and reads each module onto the main storage device (RAM 103). Thereby, the processor (CPU 101) functions as the temperature acquisition unit 81, the operation switching unit 82, the outdoor fan control unit 83, the indoor fan control unit 84, the compressor control unit 85, and the valve control unit 86 of the control device 14. Further, the computer 100 can realize a part or all of the structures of the temperature acquisition unit 81, the operation switching unit 82, the outdoor fan control unit 83, the indoor fan control unit 84, the compressor control unit 85, and the valve control unit 86 by hardware. Figure 3

[0123] In the above embodiment, the air conditioning machine 10 can change the direction of the flow of the refrigerant by the four-way valve 25, and perform the cooling operation and the heating operation. However, the air conditioning machine 10 can not have the four-way valve 25, and perform only the heating operation and the defrosting operation.

[0124] Several embodiments of the present application have been described above, but these embodiments are presented as examples, and are not intended to limit the scope of the application. These new embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made within the scope of the gist of the application. These embodiments and modifications thereof are included in the scope or gist of the application, and are included in the scope of the application and its equivalents as recited in the claims.​

Claims

1. An air conditioner, comprising: Indoor heat exchanger; Outdoor heat exchanger; The first piping connects the outdoor heat exchanger to the indoor heat exchanger and allows refrigerant to flow through it. The second piping connects the indoor heat exchanger to the outdoor heat exchanger and allows the refrigerant to flow through it. The compressor, located in the first piping, has an inlet for drawing in the refrigerant and an outlet for spraying out the refrigerant; A pressure reducer is installed on the second piping; A bypass piping has a first end connected to the first piping between the indoor heat exchanger and the outlet, and a second end connected to the second piping between the outdoor heat exchanger and the pressure reducer, through which the refrigerant can flow; A valve, provided in the bypass pipe, is capable of switching between a first state in which the refrigerant can flow between the first end and the second end in the bypass pipe, and a second state in which the flow of the refrigerant between the first end and the second end in the bypass pipe is cut off. The first heat storage material is thermally connected to the first piping between the outdoor heat exchanger and the suction inlet, and thermally connected to the bypass piping between the first end and the valve; A control device controls the valve; as well as The second heat storage material is thermally connected to the second piping between the indoor heat exchanger and the pressure reducer, and thermally connected to the bypass piping between the second end and the valve.

2. The air conditioner as described in claim 1, characterized in that, The control device sets the valve to the second state during heating operation and sets the valve to the first state during defrosting operation.

3. The air conditioner as described in claim 2, wherein, It also has an indoor air supply fan that generates an airflow that exchanges heat with the indoor heat exchanger; The control device controls the indoor air supply fan, and during the defrosting operation, the speed of the indoor air supply fan is lower than the maximum speed of the indoor air supply fan during the heating operation.

4. The air conditioner as described in claim 2 or 3, wherein, It also has an outdoor air supply fan that generates airflow to exchange heat with the outdoor heat exchanger; The control device controls the outdoor air supply fan and stops the outdoor air supply fan when the defrosting operation is in progress.

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