Air conditioner

Abstract

To provide an air conditioner capable of suppressing generation of dew condensation water in refrigerant piping on an indoor side.SOLUTION: An air conditioner includes an outdoor heat exchanger, an indoor heat exchanger, first piping, second piping, a compressor, a four-way valve, an expansion valve, and a heating mechanism. The outdoor heat exchanger is provided in an outdoor unit. The indoor heat exchanger is provided in an indoor unit. The first piping connects the indoor heat exchanger and the outdoor heat exchanger, and a refrigerant flows in it. The second piping connects the outdoor heat exchanger and the indoor heat exchanger, and a refrigerant flows in it. The compressor is provided in the first piping, and includes a suction port for sucking the refrigerant, and a discharge port for discharging the refrigerant. The four-way valve is provided in the first piping and can change the direction in which the refrigerant flows. The expansion valve is provided in the second piping. The heating mechanism is provided in the first piping between the indoor heat exchanger and the four-way valve on the indoor unit side, and heats the refrigerant flowing in the first piping.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to an air conditioner.

Background Art

[0002] An air conditioner such as an air conditioner adjusts the indoor temperature by condensing and evaporating the refrigerant in the refrigeration cycle. In the cooling operation, the refrigerant condenses in the outdoor heat exchanger (condenser) arranged on the outdoor side (outdoor unit side) and evaporates in the indoor heat exchanger (evaporator) arranged on the indoor side (indoor unit side), thereby supplying cold air into the room. Also, in the heating operation, the refrigerant evaporates in the outdoor heat exchanger (evaporator) and condenses in the indoor heat exchanger (condenser), thereby supplying warm air into the room. Such an air conditioner has indoor units connected by refrigerant pipes, and the refrigerant circulates inside them.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the indoor heat load and the refrigerant circulation amount do not match during the cooling operation of the air conditioner, or when the fins of the indoor heat exchanger are dirty, or when the condensed water bridges between the fins and the air flow deteriorates, resulting in a decrease in heat exchange efficiency (vaporization decreases), so-called "liquid back" may occur, where low-temperature liquid refrigerant flows out from the indoor heat exchanger and flows toward the compressor side. In this case, the low-temperature refrigerant flowing through the refrigerant pipes may exchange heat with the outside air, causing condensation on the surface of the refrigerant pipes or the heat insulating material wound around the refrigerant pipes. As a result, there is a problem that condensation water may cause water leakage on the indoor side.

[0005] An example of the problem to be solved by the present invention is to provide an air conditioner capable of suppressing the generation of condensed water on the refrigerant pipe on the indoor side.

Means for Solving the Problem

[0006] The air conditioner according to one embodiment of the present invention includes an outdoor heat exchanger, an indoor heat exchanger, a first pipe, a second pipe, a compressor, a four-way valve, an expansion valve, and a heating mechanism. The outdoor heat exchanger is provided in the outdoor unit. The indoor heat exchanger is provided in the indoor unit. The first pipe connects the indoor heat exchanger and the outdoor heat exchanger, and the refrigerant flows through it. The second pipe connects the outdoor heat exchanger and the indoor heat exchanger, and the refrigerant flows through it. The compressor is provided in the first pipe and has a suction port for sucking the refrigerant and a discharge port for discharging the refrigerant. The four-way valve is provided in the first pipe and can change the direction in which the refrigerant flows. The expansion valve is provided in the second pipe. The heating mechanism is provided in the first pipe between the indoor heat exchanger and the four-way valve on the indoor unit side and heats the refrigerant flowing through the first pipe.

[0007] Further, the heating mechanism of the air conditioner according to the present embodiment may include, for example, a first heat storage material thermally connected to the first pipe.

[0008] Further, the heating mechanism of the air conditioner according to the present embodiment may be provided, for example, in the first pipe inside the housing of the indoor unit.

[0009] Further, the air conditioner according to the present embodiment may include, for example, a cooling mechanism provided in the second pipe between the indoor heat exchanger and the expansion valve and cooling the refrigerant flowing through the second pipe.

[0010] Further, the cooling mechanism of the air conditioner according to the present embodiment may include, for example, a second heat storage material thermally connected to the second pipe.

[0011] Further, the heat source of the heating mechanism of the air conditioner according to the present embodiment may be, for example, the heat generation surface of a Peltier element, and the cooling source of the cooling mechanism may be the cooling surface of the Peltier element.

[0012] According to the air conditioner described above, for example, even when the refrigerant flowing out from the indoor heat exchange during the cooling operation is in a state of a low-temperature liquid, before reaching the compressor, that is, on the indoor side before reaching the outdoor unit, the refrigerant is heated at the stage of flowing through the first pipe, so that it is possible to suppress the occurrence of condensation in the refrigerant pipe. As a result, it is possible to suppress the occurrence of water leakage due to condensed water on the indoor side.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] Hereinafter, some embodiments will be described with reference to FIGS. 1 to 5. In this specification, the components according to the embodiments and the descriptions of the components may be described in a plurality of expressions. The components and their descriptions are examples and are not limited by the expressions in this specification. The components may be specified by different names from those in this specification. Also, the components may be described by expressions different from those in this specification.

[0015] FIG. 1 is an exemplary and schematic diagram showing a refrigerant circuit diagram of the air conditioner 10 according to the embodiment. The air conditioner 10 is, for example, a household air conditioner. Note that the air conditioner 10 is not limited to this example and may be other air conditioners such as commercial air conditioners. The air conditioner 10 according to the embodiment has a dehumidifying function of performing dehumidification by adjusting the superheat degree in the indoor heat exchanger 41 during the cooling operation to generate condensed water on the surface of the indoor heat exchanger 41 and collecting the condensed water.

[0016] As shown in FIG. 1, the air conditioner 10 includes an outdoor unit 11, an indoor unit 12, a refrigerant pipe 13, and a control device 14. The outdoor unit 11 is disposed outdoors, for example. The indoor unit 12 is disposed indoors, for example.

[0017] The air conditioner 10 includes a refrigeration cycle in which the outdoor unit 11 and the indoor unit 12 are connected by the refrigerant pipe 13. The refrigerant flows through the refrigerant pipe 13 between the outdoor unit 11 and the indoor unit 12. Also, the outdoor unit 11 and the indoor unit 12 are electrically connected to each other by, for example, electrical wiring.

[0018] The outdoor unit 11 includes an outdoor heat exchanger 21, an outdoor blower fan 22, a compressor 23, an accumulator 24, a four-way valve 25, an expansion valve 26, and the like. The indoor unit 12 includes an indoor heat exchanger 41, an indoor blower fan 42, a heating mechanism 31, a cooling mechanism 32, and the like.

[0019] The refrigerant pipe 13 is a pipe through which a refrigerant made of a metal such as copper or aluminum flows, for example. The refrigerant pipe 13 includes a first pipe 51 and a second pipe 52.

[0020] The first pipe 51 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41. The compressor 23, the accumulator 24, the four-way valve 25, and the heating mechanism 31 are provided in the first pipe 51. The first pipe 51 has a first region 51a, a second region 51b, a third region 51c, a fourth region 51d, and a fifth region 51e. The first region 51a is a pipe region connecting the indoor heat exchanger 41 and the heating mechanism 31. The second region 51b is a pipe region connecting the heating mechanism 31 and the four-way valve 25. The third region 51c is a pipe region connecting the four-way valve 25 and the accumulator 24. The fourth region 51d is a pipe region connecting the discharge port 23b of the compressor 23 and the four-way valve 25. The fifth region 51e is a pipe region connecting the four-way valve 25 and the outdoor heat exchanger 21. During the cooling operation, the high-pressure and high-temperature gaseous refrigerant discharged from the compressor 23 is supplied to the outdoor heat exchanger 21 side. Also, during the heating operation, the high-pressure and high-temperature gaseous refrigerant discharged from the compressor 23 is supplied to the indoor heat exchanger 41 side.

[0021] The second pipe 52 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21. The expansion valve 28 and the cooling mechanism 32 are provided in the second pipe 52. The second pipe 52 has a sixth region 52a, a seventh region 52b, and an eighth region 52c. The sixth region 52a is a pipe region connecting the indoor heat exchanger 41 and the cooling mechanism 32. The seventh region 52b is a pipe region connecting the cooling mechanism 32 and the expansion valve 28. The eighth region 52c is a pipe region connecting the expansion valve 26 and the outdoor heat exchanger 21. During the cooling operation, the refrigerant flowing out from the outdoor heat exchanger 21 is supplied to the indoor heat exchanger 41 side. Also, during the heating operation, the refrigerant flowing out from the indoor heat exchanger 41 is supplied to the outdoor heat exchanger 21 side.

[0022] The outdoor heat exchanger 21 of the outdoor unit 11 absorbs heat of the refrigerant as an evaporator or dissipates heat of the refrigerant as a condenser according to the flow direction of the refrigerant. The outdoor blower fan 22 blows air to the outdoor heat exchanger 21 to promote the heat exchange between the refrigerant and the air in the outdoor heat exchanger 21. In other words, the outdoor blower fan 22 generates an air flow that exchanges heat with the outdoor heat exchanger 21.

[0023] The compressor 23 has a suction port 23a and a discharge port 23b. The compressor 23 sucks the refrigerant from the suction port 23a and discharges the compressed refrigerant from the discharge port 23b. Thereby, the compressor 23 compresses the refrigerant in the refrigeration cycle and causes the circulation of the refrigerant.

[0024] The accumulator 24 is connected to the suction port 23a of the compressor 23. When the refrigerant contains a liquid refrigerant, the accumulator 24 separates the gaseous refrigerant from the liquid refrigerant. Thereby, the compressor 23 can suck the gaseous refrigerant that has passed through the accumulator 24 from the suction port 23a. The accumulator 24 can also serve as the suction port of the compressor 23 by being integrally formed with the compressor 23.

[0025] The four-way valve 25 is provided in the first pipe 51 and is connected to the heating mechanism 31, the accumulator 24, the outdoor heat exchanger 21, and the compressor 23. The four-way valve 25 switches the flow paths connected to the heating mechanism 31, the accumulator 24, the outdoor heat exchanger 21, and the compressor 23 during the cooling operation and the heating operation, and changes the direction in which the refrigerant flows.

[0026] The expansion valve 26 is, for example, an electromagnetic expansion valve. Note that the expansion valve 26 may be another type of expansion valve. By controlling the opening degree, the expansion valve 26 adjusts the amount of the refrigerant passing through to determine the expansion amount of the refrigerant and adjusts the refrigerant temperature.

[0027] FIG. 2 is an exemplary and schematic explanatory diagram showing the structure of the heating mechanism 31. Note that the configurations of the heating mechanism 31 and the cooling mechanism 32 are basically the same. Therefore, the configuration of the heating mechanism 31 will be described with reference to FIG. 2, and the configuration of the cooling mechanism 32 will be described as appropriate.

[0028] In FIG. 2, a cross-sectional view and a plan view of the heating mechanism 31 (cooling mechanism 32) are shown side by side. As shown in FIG. 2, the heating mechanism 31 (cooling mechanism 32) is composed of a first heat storage material 31K (second heat storage material 32K) and a first thermoelectric element 31H (second thermoelectric element 32H) that functions as a temperature adjustment element H. The first heat storage material 31K is arranged so as to be thermally connected to the first pipe 51. For example, the first heat storage material 31K is arranged so as to surround the first pipe 51. In the case of FIG. 1 (FIG. 4 described later), for ease of understanding of the configuration, the indoor heat exchanger 41 and the heating mechanism 31 are shown in a separated state, but it is desirable that the heating mechanism 31 be arranged immediately after the indoor heat exchanger 41 inside the housing 12a of the indoor unit 12. That is, it is desirable that the heating mechanism 31 be arranged on the indoor unit 12 side so as to substantially surround (thermally connect) the first region 51a of the first pipe 51. Note that the position where the heating mechanism 31 is provided may be on the indoor unit 12 side. Here, the indoor unit 12 side refers to the region inside the housing 12a constituting the indoor unit 12 and the indoor region from the housing 12a of the indoor unit 12 to the communication hole provided in the wall portion of the house and extending to the housing 11a of the outdoor unit 11 through the first pipe 51. In some cases, the first pipe 51 is configured to be selectively led out from the left side surface, right side surface, etc. of the housing 12a of the indoor unit 12 to improve the installation freedom of the indoor unit 12 in the room. In this case, a guide space (for example, a recessed groove) for storing the first pipe 51 may be formed on the surface of the back side (installation wall surface side, etc.) of the housing 12a. In the present embodiment, such a guide space is also regarded as a part inside the housing 12a. In any case, the heating mechanism 31 is a mechanism capable of heating the refrigerant on the indoor unit 12 side (indoor side). Thus, by providing the heating mechanism 31 inside the housing 12a of the indoor unit 12 on the first pipe, it is possible to complete the avoidance of dew condensation (heating and vaporization of the refrigerant) inside the indoor unit 12, realize measures against dew condensation (water leakage), and contribute to the improvement of the designability of the indoor unit 12.

[0029] Regarding the cooling mechanism 32 as well, as shown in FIG. 1, it can be arranged (thermally connected) so as to surround the second pipe 52 on the indoor unit 12 side. Note that the cooling mechanism 32 may be arranged on the outdoor unit 11 side.

[0030] Note that the first pipe 51 may be configured such that the second pipe 52 and a drain pipe (to be described later) are bundled together and inserted through a communication hole. When the first pipe 51 and the second pipe 52 are bundled, the heating mechanism 31 and the cooling mechanism 32 can be installed more preferably. Specific installation modes will be described later.

[0031] Then, the first thermoelectric element 31H is wound around the outer periphery of the first heat storage material 31K so as to surround it, for example. Also, the second thermoelectric element 32H is wound around the outer periphery of the second heat storage material 32K so as to surround it, for example. An opening 31a to which a first region 51a of the first pipe 51, which is a flow path passing through the heating mechanism 31, is connected is formed at one end side of the first heat storage material 31K, and an opening 31b to which a second region 51b of the first pipe 51 is connected is formed at the other end side. Similarly, an opening 32a to which a seventh region 52b of the second pipe 52, which is a flow path passing through the cooling mechanism 32, is connected is formed at one end side of the second heat storage material 32K, and an opening 32b to which a sixth region 52a of the second pipe 52 is connected is formed at the other end side.

[0032] The first thermoelectric element 31H (the second thermoelectric element 32H) can utilize a Peltier element that functions as a temperature adjustment element H. The Peltier element is an energy conversion element that utilizes the interaction between heat and electricity. The Peltier element (the first thermoelectric element 31H, the second thermoelectric element 32H) is, for example, a sheet-like element formed by joining two different types of metals or semiconductors at two points. When an electric current flows through this element, heat is also transported when the current flows from one contact to the other contact, one contact is heated, and the other contact is cooled. As a result, in the first thermoelectric element 31H, when the surface in contact with the first heat storage material 31K is taken as the heating surface, the first heat storage material 31K is heated, the first heat storage material 31K is warmed, and further, together with the first pipe 51, the refrigerant flowing through the first pipe 51 is warmed to promote gasification. Also, in the second thermoelectric element 32H, when the surface in contact with the second heat storage material 32K is taken as the cooling surface, the second heat storage material 32K is cooled, the second heat storage material 32K is cooled, and further, together with the second pipe 52, the refrigerant flowing through the second pipe 52 is cooled to promote liquefaction.

[0033] The first heat storage material 31K (the second heat storage material 32K) can be formed, for example, by filling a block-shaped container with a latent heat storage material. The latent heat storage material is, for example, calcium chloride. The first heat storage material 31K (the second heat storage material 32K) may have other latent heat storage materials. The refrigerant flowing through the first pipe 51 that penetrates the first heat storage material 31K may be arranged so as to be able to exchange heat with the heat stored in the first heat storage material 31K. Similarly, the refrigerant flowing through the second pipe 52 that penetrates the second heat storage material 32K may be arranged so as to be able to exchange heat with the heat stored in the second heat storage material 32K. The first pipe 51 (the second pipe 52) may penetrate the first heat storage material 31K (the second heat storage material 32K) linearly, for example, but as shown in FIG. 2, by arranging it in a meandering shape or a spiral shape, it is desirable to increase the contact area with the first heat storage material 31K (the second heat storage material 32K) so as to improve the heat exchange efficiency. Note that the first heat storage material 31K (the second heat storage material 32K) may be formed so as to directly surround the refrigerant pipe 13 (the first pipe 51 or the second pipe 52) that penetrates the inside as described above. In another embodiment, a dedicated pipe that functions as the refrigerant pipe 13 may be provided in advance inside the first heat storage material 31K (the second heat storage material 32K), and the refrigerant pipe 13 (the first pipe 51 or the second pipe 52) may be connected. In this case, the heating mechanism 31 (the cooling mechanism 32) can be separately prepared and connected to the refrigerant pipe 13, which can contribute to improving the assembly efficiency. Note that as described above, the first heat storage material 31K (the second heat storage material 32K) only needs to be thermally connected to the first pipe 51 (the second pipe 52). The first heat storage material 31K (the second heat storage material 32K) can be installed so as to directly surround the first pipe 51 (the second pipe 52), thereby efficiently realizing heat exchange with the refrigerant. In another embodiment, the first heat storage material 31K (the second heat storage material 32K) and the first pipe 51 (the second pipe 52) may be indirectly thermally connected via an air layer, a liquid layer, or other layers. In this case, while enabling an improvement in design variations, the same effect as in the case of a direct contact mode can be obtained.

[0034] In the heating mechanism 31, instead of the first thermoelectric element 31H (Peltier element) as the temperature adjustment element H, a heater element capable of temperature adjustment by electrical control may be used. When using a heater element, the heater element may be embedded inside the first heat storage material 31K. Further, if the heating mechanism 31 (cooling mechanism 32) can maintain the temperature of the first heat storage material 31K (second heat storage material 32K) within a predetermined temperature range according to the refrigerant temperature, it is not necessary to constantly drive the first thermoelectric element 31H (second thermoelectric element 32H), and ON / OFF control may be appropriately performed.

[0035] The control device 14 controls the outdoor blower fan 22, indoor blower fan 42, compressor 23, each valve, each thermoelectric element, etc. provided in the outdoor unit 11 and the indoor unit 12, and performs cooling operation, heating operation, dehumidifying operation, defrosting operation, and other operation controls. The control device 14 is composed of, for example, an outdoor control device 14a provided in the outdoor unit 11, an indoor control device 14b provided in the indoor unit 12, etc. The outdoor control device 14a and the indoor control device 14b are electrically connected to each other to transmit and receive control signals, and cooperate to control the outdoor unit 11 and the indoor unit 12. The indoor control device 14b provided in the indoor unit 12 may be controlled by inputting a signal from a remote controller operated by a user, or may be controlled by inputting a signal from an information terminal such as a smartphone through a communication device. Note that the outdoor control device 14a and the indoor control device 14b may be collectively regarded as one control device 14. In this case, the control device 14 may be provided in the outdoor unit 11 or the indoor unit 12, but can be provided in the indoor unit 12, for example.

[0036] The control device 14 is a computer having a control device such as a CPU (Central Processing Unit) or a microcontroller, a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage device such as a flash memory. Note that the control device 14 is not limited to this example.

[0037] FIG. 3 is an exemplary and schematic block diagram showing the control device 14 of the air conditioner 10 of the present embodiment and the components controlled by the control device 14. As shown in FIG. 3, the air conditioner 10 of the present embodiment includes an outdoor fan drive circuit 71, an indoor fan drive circuit 72, an inverter circuit 73, a four-way valve drive circuit 74, an expansion valve drive circuit 75, a first thermoelectric element drive circuit 76, a second thermoelectric element drive circuit 77, and the like.

[0038] The outdoor fan drive circuit 71 is a drive circuit for the outdoor blower fan 22. The indoor fan drive circuit 72 is a drive circuit for the indoor blower fan 42. The inverter circuit 73 performs inverter control on the compressor 23 and changes the frequency of the compressor 23. The inverter circuit 73 is, for example, an inverter circuit of the PAM (Pulse Amplitude Modulation) method. Note that the inverter circuit 73 is not limited to this example.

[0039] The four-way valve drive circuit 74 is a drive circuit for the four-way valve 25. The expansion valve drive circuit 75 is a drive circuit for the expansion valve 26. The first thermoelectric element drive circuit 76 is a drive circuit for the first thermoelectric element 31H. The second thermoelectric element drive circuit 77 is a drive circuit for the second thermoelectric element 32H.

[0040] The control device 14 is connected to temperature sensors T (T1 to T7, Su, etc.) provided in the indoor heat exchanger 41, the outdoor heat exchanger 21, the heating mechanism 31, the cooling mechanism 32, etc., in addition to the refrigerant pipe 13, the outdoor fan drive circuit 71, the indoor fan drive circuit 72, the inverter circuit 73, the four-way valve drive circuit 74, the expansion valve drive circuit 75, the first thermoelectric element drive circuit 76, and the second thermoelectric element drive circuit 77. The control device 14 includes a temperature acquisition unit 91, an operation switching unit 92, an outdoor fan control unit 93, an indoor fan control unit 94, a compressor control unit 95, a valve control unit 96, and a thermoelectric element control unit 97.

[0041] The temperature acquisition unit 91 measures the temperature of each part within the refrigeration cycle using each temperature sensor T, and reflects it in the control of each drive circuit. For example, the temperature sensor T1 is arranged on the indoor heat exchanger 41 to detect the temperature of the indoor heat exchanger 41. The temperature sensor T2 is arranged near the indoor heat exchanger 41 in the first region 51a of the first pipe 51 to detect the temperature of the refrigerant. The temperature sensor T3 is arranged on the heating mechanism 31 (the first heat storage material 31K) to detect the temperature of the first heat storage material 31K (the refrigerant flowing through the first pipe 51). The temperature sensor T4 is arranged on the outdoor heat exchanger 21 to detect the temperature of the outdoor heat exchanger 21. The temperature sensor T5 is arranged near the expansion valve 26 in the eighth region 52c of the second pipe 52 to detect the temperature of the refrigerant passing through the expansion valve 26. The temperature sensor T6 is arranged near the expansion valve 26 in the seventh region 52b of the second pipe 52 to detect the temperature of the refrigerant passing through the expansion valve 26. The temperature sensor T7 is arranged on the cooling mechanism 32 (the second heat storage material 32K) to detect the temperature of the second heat storage material 32K (the refrigerant flowing through the second pipe 52). The temperature sensor Su is arranged near the accumulator 24 in the third region 51c of the first pipe 51 to detect the temperature of the refrigerant. Although not shown in the figure, within the refrigeration cycle, in addition to the above-described temperature sensor T, a plurality of other temperature sensors may be arranged, and their detection results are reflected in each control.

[0042] The operation switching unit 92 performs switching between the cooling operation, heating operation, dehumidifying operation, defrosting operation, and other operations in the air conditioner 10.

[0043] The outdoor fan control unit 93 controls the outdoor blower fan 22. For example, the outdoor fan control unit 93 controls the outdoor fan drive circuit 71 to control the rotational speed of the motor of the outdoor blower fan 22.

[0044] The indoor fan control unit 94 controls the indoor blower fan 42. For example, the indoor fan control unit 94 controls the indoor fan drive circuit 72 to control the rotational speed of the motor of the indoor blower fan 42, and adjusts the amount (air volume, wind strength) of cold air or warm air blown into the room.

[0045] The compressor control unit 95 controls the compressor 23. For example, the compressor control unit 95 controls the inverter circuit 73 to control the frequency (operating frequency) of the compressor 23 by inverter control, thereby adjusting the compression capacity of the compressor 23.

[0046] The valve control unit 96 controls the four-way valve 25 and the expansion valve 26. The valve control unit 96 drives the actuator of the four-way valve 25 by controlling the four-way valve drive circuit 74 to change the direction in which the refrigerant flows through the four-way valve 25. The valve control unit 96 changes the opening degree of the expansion valve 26 by controlling the expansion valve drive circuit 75 to adjust the refrigerant flow rate and the expansion amount, and also adjusts the refrigerant temperature. The thermoelectric element control unit 97 controls the first thermoelectric element drive circuit 76 and the second thermoelectric element drive circuit 77 to change the amount of current supplied, thereby adjusting the heat generation amount (cooling amount) in the first thermoelectric element 31H and the second thermoelectric element 32H.

[0047] An example of the operating state of the air conditioner 10 configured as described above will be described with reference to FIGS. 1 and 4.

[0048] First, with reference to FIG. 1, the cooling operation of the air conditioner 10 will be described together with the refrigerant flow pattern.

[0049] In the case of cooling operation, when the air conditioner 10 starts up and the cooling operation starts simultaneously, the outdoor air supply fan 22, the compressor 23, and the indoor air supply fan 42 are stopped. In this case, the outdoor fan control unit 93, the indoor fan control unit 94, and the compressor control unit 95 start the outdoor air supply fan 22, the indoor air supply fan 42, and the compressor 23 at the start of the cooling operation.

[0050] During the cooling operation, the outdoor fan control unit 93 adjusts the rotational speed of the outdoor blower fan 22. The indoor fan control unit 94 adjusts the rotational speed of the indoor blower fan 42. For example, the indoor fan control unit 94 controls the indoor blower fan 42 between weak wind (low speed) operation and strong wind (high speed) operation according to the temperature of the room where the indoor unit 12 is installed or a signal input from the remote controller, and the compressor control unit 95 adjusts the frequency of the compressor 23.

[0051] When the cooling operation is started, the valve control unit 96 controls the four-way valve drive circuit 74 to change the direction in which the refrigerant flows in the four-way valve 25 for the cooling operation. Further, the valve control unit 96 controls the expansion valve drive circuit 75 to change the opening and closing state of the valve so as to realize the expansion state of the refrigerant according to the cooling capacity required by the user in the expansion valve 26. Further, the thermoelectric element control unit 97 controls the first thermoelectric element drive circuit 76 and the second thermoelectric element drive circuit 77, and controls the control states of the first thermoelectric element 31H and the second thermoelectric element 32H according to the temperature of the refrigerant flowing through each refrigerant pipe 13.

[0052] Specifically, the four-way valve 25 connects the fourth region 51d and the fifth region 51e of the first pipe 51, and connects the discharge port 23b of the compressor 23 and the outdoor heat exchanger 21. As a result, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 23 is supplied to the outdoor heat exchanger 21 side. In the outdoor heat exchanger 21, by exchanging heat with the outside air, the high-pressure and high-temperature gaseous refrigerant is changed into a medium-temperature and high-pressure liquid refrigerant. Further, the valve control unit 96 controls the expansion valve drive circuit 75, controls the opening degree of the expansion valve 26, adjusts the expansion state of the liquid refrigerant supplied from the outdoor heat exchanger 21 to reduce the pressure, and adjusts (lowers) the refrigerant temperature.

[0053] The liquid refrigerant that has been expanded by the expansion valve 26 and cooled to a low temperature is supplied to the cooling mechanism 32. The second heat storage material 32K of the cooling mechanism 32 is cooled to a temperature lower than the temperature of the refrigerant flowing through the seventh region 52b of the second pipe 52 by controlling the temperature of the second thermoelectric element 32H. That is, the temperature of the liquid refrigerant passing through the second pipe 52 can be further cooled. Here, let the detected value of the temperature sensor T4 be the T4 value, and the detected value of the temperature sensor T5 be the T5 value. In this case, for example, the thermoelectric element control unit 97 controls the second thermoelectric element drive circuit 77 to control the second thermoelectric element 32H so that the degree of supercooling (subcool) SC = T4 value - T5 value ≒ 5°C, and cools the cooling mechanism 32 (the second heat storage material 32K). As a result, for example, even when the outside air temperature is high and sufficient liquefaction cannot be achieved in the outdoor heat exchanger 21 and the refrigerant passing through the expansion valve 26 contains gaseous refrigerant, the refrigerant can be supplemented and cooled by the cooling mechanism 32 to liquefy the refrigerant. That is, it becomes possible to supply the refrigerant sufficiently liquefied to the indoor heat exchanger 41, and the cooling efficiency in the indoor unit 12 can be improved. In other words, the cooling mechanism 32 can increase the enthalpy of the refrigerant and contribute to ensuring or improving the cooling capacity. In addition, the cooling effect by the cooling mechanism 32 can also contribute to reducing the condensation capacity in the outdoor heat exchanger 21. That is, in the air conditioner 10 equipped with the cooling mechanism 32, when trying to achieve the same cooling capacity as the conventional system, the outdoor heat exchanger 21 can be miniaturized. Or, when the same outdoor heat exchanger 21 is installed, it can contribute to improving the cooling capacity.

[0054] Then, the indoor unit 12 can discharge cold air into the room as a result of the heat exchange in the indoor heat exchanger 41. The refrigerant discharged from the indoor heat exchanger 41 is supplied to the heating mechanism 31.

[0055] As described above, during the cooling operation of the air conditioner 10, the indoor heat load and the refrigerant circulation amount may not match, or it may be caused by the fouling of the fins of the indoor heat exchanger 41, or the condensed water that may be generated during the cooling operation may bridge between the fins and deteriorate the air flow, resulting in a decrease in heat exchange efficiency (a decrease in vaporization). As a result, a so-called "liquid back" may occur in which the low-temperature liquid refrigerant flows out of the indoor heat exchanger 41 and flows toward the compressor side. In this case, the low-temperature refrigerant flowing through the first pipe 51 (the first region 51a to the third region 51c) may exchange heat with the outside air (indoor air), resulting in condensation around the first pipe 51. As a result, there is a possibility of water leakage occurring on the indoor side including the first region 51a and the second region 51b of the first pipe 51. As a measure against water leakage, it is conceivable to reduce the refrigerant circulation amount and increase the ratio of the refrigerant vaporized in the indoor heat exchanger 41 (take superheat). However, since the gaseous refrigerant has a low contribution rate to dehumidification, the humidity in the room may increase, causing discomfort to the user.

[0056] Therefore, the air conditioner 10 of the present embodiment maintains the dehumidifying capacity without taking superheat in the indoor heat exchanger 41. That is, the dehumidifying capacity is improved by increasing the liquid refrigerant ratio in the outdoor heat exchanger 21. In this case, however, the possibility of liquid refrigerant being discharged from the outdoor heat exchanger 21 increases. Therefore, the heating mechanism 31 disposed in the first pipe 51 on the indoor unit 12 side heats the liquid refrigerant to vaporize it. As a result, heat exchange with the indoor air is suppressed in the first pipe 51 on the indoor unit 12 side, and the occurrence of condensation (condensed water) is avoided. Here, the detected value of the temperature sensor Su is defined as the Su value, and the detected value of the temperature sensor T3 is defined as the T3 value. In this case, the compressor control unit 95 controls the frequency of the compressor 23, the valve control unit 96 controls the opening degree of the expansion valve 26, and the thermoelectric element control unit 97 controls the first thermoelectric element 31H by the first thermoelectric element drive circuit 76 to heat the heating mechanism 31 (the first heat storage material 31K) so that the superheat degree SH = Su value - T3 value = 2°C to 3°C. As a result, the low-temperature liquid refrigerant discharged from the indoor heat exchanger 41 can be heated to promote vaporization. Thereby, liquid back to the compressor 23 side can be suppressed, and the occurrence of condensation (condensed water) in the first pipe 51 on the indoor unit 12 side can be suppressed. Note that the first pipe 51 is often drawn out to the outdoor unit 11 side in a state where it is joined with a drain pipe connected to a drain pan that has collected the condensed water generated for dehumidification on the surface of the indoor heat exchanger 41. In this case, the heating mechanism 31 can also heat the drain pipe, and it is also possible to suppress the occurrence of condensed water that may occur around the drain pipe. The heating mechanism 31 may be disposed over the entire length of the first pipe 51 in the indoor unit 12, but is provided in a predetermined range near the outdoor heat exchanger 21. If vaporization of the refrigerant can be sufficiently performed there, liquid back and the occurrence of condensation on the indoor unit 12 side can be suppressed. That is, the installation range of the heating mechanism 31 may be minimized near the indoor heat exchanger 41, which may contribute to reducing the component cost. Then, the refrigerant vaporized by the heating mechanism 31 passes through the four-way valve 25 and returns to the compressor 23 via the accumulator 24. As a result, the refrigerant circulation cycle as described above continues.

[0057] Thus, during the cooling operation of the air conditioner 10, by providing the heating mechanism 31 in the first pipe 51 of the indoor unit 12 and heating (vaporizing) the refrigerant, it is possible to suppress a decrease in dehumidifying capacity and suppress liquid back to the compressor 23 side and water leakage due to condensed water in the indoor unit 12 with an easy configuration. Further, by providing the cooling mechanism 32 in the second pipe 52 of the indoor unit 12 and lowering the temperature of the refrigerant flowing toward the indoor heat exchanger 41, it is possible to improve the cooling capacity and dehumidifying capacity with an easy configuration.

[0058] Subsequently, with reference to FIG. 4, the heating operation of the air conditioner 10 will be described together with the refrigerant flow pattern.

[0059] In the case of the heating operation, when the air conditioner 10 is started simultaneously with the start of the heating operation, the outdoor air supply fan 22, the compressor 23, and the indoor air supply fan 42 are stopped. In this case, the outdoor fan control unit 93, the indoor fan control unit 94, and the compressor control unit 95 start the outdoor air supply fan 22, the indoor air supply fan 42, and the compressor 23 at the start of the heating operation.

[0060] During the heating operation, the outdoor fan control unit 93 adjusts the rotation speed of the outdoor air supply fan 22. The indoor fan control unit 94 adjusts the rotation speed of the indoor air supply fan 42. For example, the indoor fan control unit 94 controls the indoor air supply fan 42 between weak wind (low speed) operation and strong wind (high speed) operation according to the temperature of the room where the indoor unit 12 is installed or a signal input from the remote controller, and the compressor control unit 95 adjusts the frequency of the compressor 23.

[0061] When the heating operation is started, the valve control unit 96 controls the four-way valve drive circuit 74 to change the direction in which the refrigerant flows in the four-way valve 25 for the heating operation. Further, the valve control unit 96 controls the expansion valve drive circuit 75 to change the opening / closing state of the expansion valve 26 for the heating operation. Further, the thermoelectric element control unit 97 controls the first thermoelectric element drive circuit 76 and the second thermoelectric element drive circuit 77, and controls the control states of the first thermoelectric element 31H and the second thermoelectric element 32H according to the temperature of the refrigerant flowing through each refrigerant pipe 13.

[0062] Specifically, the four-way valve 25 connects the fourth region 51d and the second region 51b of the first pipe 51, and connects the discharge port 23b of the compressor 23 and the heating mechanism 31. The heating mechanism 31 heats the first heat storage material 31K by the first thermoelectric element 31H. At this time, when the blowing temperature during the heating operation of the indoor unit 12 is, for example, 45°C, the frequency of the compressor 23 is controlled so that it becomes, for example, 4°C lower than the required condensation temperature (45°C) of the refrigerant in the indoor heat exchanger 41 when realizing this. In the case of normal heating operation, at a blowing temperature of 45°C, a condensation temperature of 45°C, and a supercooling degree of 5°C, the high-pressure state of the refrigerant becomes, for example, 2.7 MPa. In the case of the air conditioner 10 of this embodiment, even at the same blowing temperature of 45°C, the high-pressure state of the refrigerant is set to, for example, 2.44 MPa, and the differential energy is used to heat the refrigerant by the heating mechanism 31 so as to control the indoor unit 12 to realize the same blowing temperature (45°C). That is, by controlling the temperature of the heating mechanism 31, it becomes possible to reduce the workload of the compressor 23, which can contribute to energy saving. In addition, the reduction of the workload of the compressor 23 can also contribute to the miniaturization of the compressor 23, in other words.

[0063] The high-temperature and high-pressure gaseous refrigerant heated by passing through the heating mechanism 31 is supplied to the indoor heat exchanger 41. As a result, during the heating operation, the indoor heat exchanger 41 functions as a condenser and releases warm air into the room as a result of heat exchange.

[0064] The medium-temperature and high-pressure liquid refrigerant discharged from the indoor heat exchanger 41 is supplied to the cooling mechanism 32 via the second pipe 52. By cooling the refrigerant in the cooling mechanism 32 to promote liquefaction, the temperature of the liquid refrigerant supplied to the expansion valve 26 is lowered. As a result, the temperature of the refrigerant that can be supplied to the outdoor heat exchanger 21 can be lowered. Therefore, during the heating operation, part of the heat exchange performed by the outdoor heat exchanger 21 can be performed by the cooling mechanism 32, which can contribute to the miniaturization of the outdoor heat exchanger 21. Note that the indoor heat exchanger may be provided with a subcooling circuit for liquefying the refrigerant. However, in the case of the air conditioner 10 of the present embodiment, liquefaction is possible by the cooling mechanism 32, so a subcooling circuit is not necessary. As a result, it is possible to contribute to the miniaturization of the indoor heat exchanger 41. Further, since the liquefaction of the refrigerant is reduced in the indoor heat exchanger 41, it is also possible to contribute to suppressing a decrease in the blowing temperature (improving the blowing temperature) in the indoor unit 12.

[0065] The refrigerant cooled by the cooling mechanism 32 is supplied to the expansion valve 26. The valve control unit 96 controls the expansion valve drive circuit 75 and adjusts the opening state of the expansion valve 26 to reduce the pressure of the refrigerant and cool it by expansion and supply it to the outdoor heat exchanger 21.

[0066] In the case of the heating operation, the liquid refrigerant cooled by passing through the expansion valve 26 is vaporized by exchanging heat with the outside air in the outdoor heat exchanger 21 that functions as an evaporator and flows out to the compressor 23 side. By lowering the temperature of the refrigerant supplied to the outdoor heat exchanger 21, the vaporization efficiency can be improved. As a result, it is possible to suppress liquid backflow to the compressor 23 side. Further, since the vaporization efficiency in the outdoor heat exchanger 21 can be improved, it is also possible to contribute to reducing the capacity, that is, miniaturizing the outdoor heat exchanger 21.

[0067] In this way, during the heating operation, the air conditioner 10 can additionally heat the high-pressure and high-temperature gaseous refrigerant supplied from the compressor 23 by the heating mechanism 31 provided on the indoor unit 12 side. Therefore, when discharging the same blowing temperature as before from the indoor unit 12, the workload of the compressor 23 can be reduced. Further, by cooling and liquefying the refrigerant in the cooling mechanism 32 provided on the indoor unit 12 side, it becomes possible to supplement a part of the capacity of the outdoor heat exchanger 21, contributing to the miniaturization of the outdoor heat exchanger 21. Also, since a configuration for actively liquefying the refrigerant on the indoor heat exchanger 41 side becomes unnecessary, it can also contribute to the miniaturization of the outdoor heat exchanger 21 (indoor unit 12).

[0068] By the way, in the case of the refrigerant system diagram of the air conditioner 10 shown in FIGS. 1 and 4, the heating mechanism 31 includes the first thermoelectric element 31H as the temperature adjustment element H, and the cooling mechanism 32 includes the second thermoelectric element 32H as the temperature adjustment element H. In another embodiment, a configuration in which the temperature adjustment element H is shared may be adopted.

[0069] FIG. 5 is an exemplary and schematic diagram showing that the heat source of the heating mechanism 31 and the cooling source of the cooling mechanism 32 of the air conditioner 10 are realized by a thermoelectric element (Peltier element) as a temperature adjustment element H. In the case of the air conditioner 10, in the indoor unit 12, the first pipe 51 and the second pipe 52 connected to the indoor heat exchanger 41 are connected at a proximate position and are arranged, for example, in a parallel manner. Therefore, as shown in FIG. 5, the heat generating surface HH of the Peltier element that functions as the first thermoelectric element 31H, which is the temperature adjustment element H, is brought into contact with the first heat storage material 31K side of the heating mechanism 31 to serve as the heat source. Further, the cooling surface HC of the same Peltier element that functions as the second thermoelectric element 32H, which is the temperature adjustment element H, is brought into contact with the second heat storage material 32K side of the cooling mechanism 32 to serve as the cooling source. As a result, the heating mechanism 31 and the cooling mechanism 32 can be simultaneously temperature-controlled by a single temperature adjustment element H (Peltier element). As a result, it is possible to contribute to the simplification of the configuration, cost reduction, and miniaturization of the indoor unit 12. Note that it is desirable to provide a heat insulation wall or the like so as to thermally separate the first heat storage material 31K and the second heat storage material 32K so that heat transfer does not occur between the heated first heat storage material 31K and the cooled second heat storage material 32K.

[0070] The air conditioner 10 according to the embodiment described above includes an outdoor heat exchanger 21, an indoor heat exchanger 41, a first pipe 51, a second pipe 52, a compressor 23, a four-way valve 25, an expansion valve 26, and a heating mechanism 31. The outdoor heat exchanger 21 is provided in the outdoor unit 11. The indoor heat exchanger 41 is provided in the indoor unit 12. The first pipe 51 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21, and refrigerant flows through it. The second pipe 52 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41, and refrigerant flows through it. The compressor 23 is provided in the first pipe 51 and has a suction port 23a for sucking refrigerant and a discharge port 23b for discharging refrigerant. The four-way valve 25 is provided in the first pipe 51 and can change the direction in which the refrigerant flows. The expansion valve 26 is provided in the second pipe 52. The heating mechanism 31 is provided in the first pipe 51 between the indoor heat exchanger 41 and the four-way valve 25 on the indoor unit 12 side, and heats the refrigerant flowing through the first pipe 51. According to this configuration, for example, even if the refrigerant flowing out of the indoor heat exchanger 41 during the cooling operation is in a state of a low-temperature liquid, it is heated at the stage of flowing through the indoor unit 12 side before reaching the compressor, that is, before reaching the outdoor unit 11. Therefore, it is possible to suppress the occurrence of condensation in the first pipe 51 (refrigerant pipe 13). As a result, it is possible to suppress the occurrence of water leakage due to condensed water on the indoor unit side.

[0071] Further, the heating mechanism 31 of the air conditioner 10 may include, for example, a first heat storage material 31K that is thermally connected to the first pipe 51. According to this configuration, for example, the refrigerant flowing through the first pipe 51 passing through the heating mechanism 31 can be efficiently heated.

[0072] Further, the heating mechanism 31 of the air conditioner 10 may be provided in the first pipe 51 inside the housing 12a of the indoor unit 12. According to this configuration, for example, it is possible to complete the avoidance of condensation inside the indoor unit 12 and contribute to the improvement of the designability of the indoor unit 12.

[0073] Further, the air conditioner 10 may be provided with a cooling mechanism 32 provided, for example, in a second pipe 52 between the indoor heat exchanger 41 and the expansion valve 26, and configured to cool the refrigerant flowing through the second pipe 52. According to this configuration, for example, during the cooling operation, the temperature of the refrigerant supplied to the indoor heat exchanger 41 can be lowered, contributing to an improvement in cooling efficiency. Also, during the heating operation, a part of the heat exchange performed by the outdoor heat exchanger 21 can be supplemented by the cooling mechanism 32, contributing to the miniaturization of the outdoor heat exchanger 21.

[0074] Further, the cooling mechanism 32 of the air conditioner 10 may include, for example, a second heat storage material 32K thermally connected to the second pipe 52. According to this configuration, for example, the refrigerant flowing through the second pipe 52 passing through the cooling mechanism 32 can be efficiently cooled.

[0075] Also, the heat source of the heating mechanism 31 of the air conditioner 10 may be, for example, the heat generation surface HH of a Peltier element (temperature adjustment element H), and the cooling source of the cooling mechanism 32 may be the cooling surface HC of the Peltier element (temperature adjustment element H). According to this configuration, it becomes possible to obtain a heating effect and a cooling effect with a single Peltier element (temperature adjustment element H), contributing to the simplification of the structure of the indoor unit 12 of the air conditioner 10, cost reduction, and miniaturization of the indoor unit 12.

[0076] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0077] 10...Air conditioner, 11...Outdoor unit, 12...Indoor unit, 13...Refrigerant piping, 14...Control device, 21...Outdoor heat exchanger, 23...Compressor, 24...Accumulator, 25...Four-way valve, 26...Expansion valve, 31...Heating mechanism, 31H...First thermoelectric element, 31K...First heat storage material, 32...Cooling mechanism, 32H...Second thermoelectric element, 32K...Second heat storage material, 41...Indoor heat exchanger, 51...First piping, 52...Second piping.

Claims

1. An outdoor heat exchanger provided in an outdoor unit, An indoor heat exchanger provided in an indoor unit, A first pipe connecting the indoor heat exchanger and the outdoor heat exchanger through which a refrigerant flows, A second pipe connecting the outdoor heat exchanger and the indoor heat exchanger through which the refrigerant flows, A compressor provided in the first pipe having a suction port for sucking the refrigerant and a discharge port for discharging the refrigerant, A four-way valve provided in the first pipe capable of changing the flow direction of the refrigerant, An expansion valve provided in the second pipe, A heating mechanism provided in the first pipe between the indoor heat exchanger and the four-way valve on the indoor unit side for heating the refrigerant flowing through the first pipe, An air conditioner comprising the above components.

2. The air conditioner according to claim 1, wherein the heating mechanism includes a first heat storage material thermally connected to the first pipe.

3. The air conditioner according to claim 1, wherein the heating mechanism is provided in the first pipe inside the housing of the indoor unit.

4. The air conditioner according to claim 1, further comprising a cooling mechanism provided in the second pipe between the indoor heat exchanger and the expansion valve for cooling the refrigerant flowing through the second pipe.

5. The air conditioner according to claim 4, wherein the cooling mechanism includes a second heat storage material thermally connected to the second pipe.

6. The air conditioner according to claim 4, wherein the heat source of the heating mechanism is the heat generation surface of a Peltier element, and the cooling source of the cooling mechanism is the cooling surface of the Peltier element.

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