Air conditioning system

Abstract

This aims to suppress the increased time required for defrosting and the resulting increase in size and mass. [Solution] The air conditioning system includes a compressor having a discharge section and a suction section; an indoor heat exchanger having a first refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a third refrigerant inlet and a fourth refrigerant inlet and a second

Description

Technical Field

[0001] The present invention relates to an air conditioner.

Background Art

[0002] When heating operation is performed by a heat pump type air conditioner, when frosting occurs on the outdoor heat exchanger, defrosting may be performed by switching from the heating cycle to the cooling cycle. However, in this defrosting method, even if the indoor fan is stopped, cold air is gradually released from the indoor unit, so there is a drawback that the heating feeling is lost. Therefore, there is a refrigeration cycle device in which a heat storage tank for storing the waste heat of the compressor is provided in the outdoor unit, and defrosting is performed using the heat stored in the heat storage tank (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the refrigeration cycle device described in Patent Document 1, during defrosting and heating operations, a part of the vapor-phase refrigerant output from the discharge port of the compressor is supplied to the liquid side of the outdoor heat exchanger, and the outdoor heat exchanger is heated.

[0005] However, in the outdoor heat exchanger, the diameter of the liquid-side pipe is often formed smaller than the diameter of the gas-side pipe. In such an outdoor heat exchanger, it becomes difficult for the large-volume vapor-phase refrigerant to flow, and the flow rate decreases. For this reason, the defrosting ability decreases, and the time required for defrosting becomes longer.

[0006] In addition, since the defrosting ability changes depending on the amount of heat stored in the heat storage tank, when the amount of heat stored in the heat storage tank is increased to stabilize the defrosting ability, the size and mass of the product increase.

[0007] Therefore, the present invention aims to provide an air conditioning system that can suppress the increase in the time required for defrosting, as well as the increase in size and mass. [Means for solving the problem]

[0008] An air conditioning system according to one aspect of the present invention includes a compressor having a discharge section and a suction section; an indoor heat exchanger having a first refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a third refrigerant inlet and a fourth refrigerant inlet and a second

[0009] In this configuration, the discharge section for discharging gaseous refrigerant is connected to the first or third refrigerant inlet / outlet, but not to the second and fourth refrigerant inlets / outlets. This prevents high-pressure gaseous refrigerant from being supplied to the second and fourth refrigerant inlets / outlets during heating / defrosting, heating, and cooling operations. As a result, the refrigerant is supplied to the indoor or outdoor heat exchanger, respectively, from the first or third refrigerant inlet / outlet, which are more suitable for the flow of large-volume gaseous refrigerant, thus suppressing a decrease in flow rate and thus reducing the time required for defrosting. Furthermore, in the configuration where an auxiliary heat exchanger is provided, for example, heat contained in the refrigerant flowing from the indoor heat exchanger to the first piping can be transferred to the refrigerant flowing from the fourth piping to the second piping. Since the indoor heat exchanger is a stable heat source, the supply of heat to the refrigerant flowing through the second piping can be stabilized and refrigerant evaporation can be promoted without providing a large-sized or large-mass heat storage tank. Therefore, it is possible to provide an air conditioning system that can suppress the time required for defrosting and the increase in size and mass.

[0010] In the above embodiment, the fourth pipe may connect the other end of the second pipe to the space between the expansion valve and the fourth refrigerant inlet / outlet in the third pipe.

[0011] In this configuration, where the fourth pipe is connected between the expansion valve and the fourth refrigerant inlet / outlet, the refrigerant flow rate on the indoor unit side can be easily controlled by the expansion valve, thereby suppressing a decrease in the discharge temperature.

[0012] In the above embodiment, when switching from heating operation to heating defrosting operation, the opening of the two-way valve may occur before or simultaneously with the switching operation of the first switching valve.

[0013] According to this embodiment, when switching from heating operation to heating defrosting operation, pressure fluctuations of the refrigerant in the refrigerant circuit can be suppressed.

[0014] In the above embodiment, when switching from heating defrosting operation to heating operation, the switching operation of the first switching valve may be performed before or simultaneously with the closing operation of the two-way valve.

[0015] According to this embodiment, when switching from heating and defrosting operation to heating operation, pressure fluctuations of the refrigerant in the refrigerant circuit can be suppressed.

[0016] In the above embodiment, the air conditioning system may further include a pressure reducer provided in the fourth piping.

[0017] According to this embodiment, the refrigerant pressure on the auxiliary heat exchanger side of the pressure reducer can be lowered, thereby lowering the refrigerant temperature and increasing the temperature difference between the refrigerant flowing through the first pipe and the refrigerant flowing through the second pipe. This increases the heat transfer from the refrigerant flowing through the first pipe to the refrigerant flowing through the second pipe, thus promoting the evaporation of the refrigerant flowing through the second pipe. Furthermore, the pressure drop of the refrigerant on the fourth refrigerant inlet / outlet side of the pressure reducer due to the compressor's suction can be suppressed, thus suppressing the temperature drop on the fourth refrigerant inlet / outlet side of the outdoor heat exchanger. This effectively prevents a decrease in the defrosting capacity of the outdoor heat exchanger and an increase in the time required for defrosting.

[0018] In the above embodiment, the first switching valve and the second switching valve connect the third refrigerant inlet / outlet and the first refrigerant inlet / outlet, respectively, to the discharge section during heating and defrosting operation, and the two-way valve may be opened during the heating and defrosting operation.

[0019] According to this embodiment, the refrigerant can be circulated so that the air conditioning system operates as a defrosting and heating system.

[0020] In the above embodiment, the temperature of the refrigerant in the first piping may be higher than the temperature of the refrigerant in the second piping.

[0021] According to this aspect, heat can be transferred from the refrigerant flowing through the first pipe to the refrigerant flowing through the second pipe, so that the evaporation of the refrigerant flowing through the second pipe can be promoted.

[0022] In the above aspect, during the heating operation, the first switching valve may connect the third refrigerant inlet / outlet to the suction part, and the second switching valve may connect the first refrigerant inlet / outlet to the discharge part during the heating operation. The two-way valve may be closed during the heating operation.

[0023] According to this aspect, the refrigerant can be circulated so that the air conditioner operates as a heating device.

[0024] In the above aspect, during the cooling operation, the first switching valve may connect the third refrigerant inlet / outlet to the discharge part, and the second switching valve may connect the first refrigerant inlet / outlet to the suction part during the cooling operation. The two-way valve may be closed during the cooling operation.

[0025] According to this aspect, the refrigerant can be circulated so that the air conditioner operates as a cooling device.

[0026] An air conditioner according to an aspect of the present invention includes a compressor, an indoor heat exchanger, an outdoor heat exchanger, a first switching valve for switching the connection state between the outdoor heat exchanger and the compressor, and a second switching valve for switching the connection state between the indoor heat exchanger and the compressor.

[0027] According to this aspect, the combination of the flow paths through which the refrigerant flows into the indoor heat exchanger and the outdoor heat exchanger can be increased, so that it is possible to easily realize a heating defrosting operation in which defrosting is performed while maintaining heating.

[0028] In the above aspect, during the heating defrosting operation in which defrosting is performed while maintaining heating, the connection state of the first switching valve may be the same as the connection state of the first switching valve during the cooling operation.

[0029] According to this embodiment, during heating and defrosting operation, a refrigerant circulation path is formed that allows high-temperature, high-pressure gaseous refrigerant to flow to the outdoor heat exchanger, thereby improving the efficiency of defrosting. Furthermore, since switching from heating operation to heating and defrosting operation can be achieved with a simple operation of switching the connection state of the first switching valve, switching between heating and defrosting operation and heating operation becomes easy, and instantaneous fluctuations in refrigerant pressure within the refrigerant circuit during switching can be suppressed.

[0030] In the above embodiment, the compressor has a discharge section and a suction section, the indoor heat exchanger has a first gas-side refrigerant inlet / outlet, the outdoor heat exchanger has a second gas-side refrigerant inlet / outlet, the first switching valve switches between a state in which the second gas-side refrigerant inlet / outlet and the discharge section are connected and a state in which the second gas-side refrigerant inlet / outlet and the suction section are connected, and the second switching valve may switch between a state in which the first gas-side refrigerant inlet / outlet and the discharge section are connected and a state in which the first gas-side refrigerant inlet / outlet and the suction section are connected.

[0031] According to this embodiment, in addition to heating operation in which the first switching valve connects the second gas-side refrigerant inlet / outlet to the suction part and the second switching valve connects the first gas-side refrigerant inlet / outlet to the discharge part, and cooling operation in which the first switching valve connects the second gas-side refrigerant inlet / outlet to the discharge part and the second switching valve connects the first gas-side refrigerant inlet / outlet to the suction part, it is possible to realize heating and cooling operation in which the first switching valve connects the second gas-side refrigerant inlet / outlet to the discharge part and the second switching valve connects the first gas-side refrigerant inlet / outlet to the discharge part. [Effects of the Invention]

[0032] According to the present invention, it is possible to provide an air conditioning system that can suppress the increase in the time required for defrosting and the increase in size and mass. [Brief explanation of the drawing]

[0033] [Figure 1] This diagram shows an overview of the heating and defrosting operation of the air conditioning system 101 according to this embodiment. [Figure 2] This figure shows an overview of the heating operation of the air conditioning system 101 according to this embodiment. [Figure 3] This diagram shows an overview of the cooling operation of the air conditioning system 101 according to this embodiment. [Modes for carrying out the invention]

[0034] The embodiments of the present invention will be described below in detail with reference to the drawings. The embodiments described below are merely examples of how to implement the present invention and are not intended to limit the scope of the invention. Furthermore, to facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations may be omitted.

[0035] [During heating and defrosting operation, defrosting is performed while maintaining heating.] Figure 1 is a diagram illustrating the overview of the heating and defrosting operation of the air conditioning system 101 according to this embodiment. As shown in Figure 1, the air conditioning system 101 comprises an indoor unit 1 and an outdoor unit 2. The indoor unit 1 includes an indoor heat exchanger 13. The indoor heat exchanger 13 has a first refrigerant inlet / outlet 51 and a second refrigerant inlet / outlet 52.

[0036] The outdoor unit 2 includes a compressor 11, branch pipes 12 and 16, expansion valves 14 and 18 (examples of "two-way valves" and "pressure reducers"), an outdoor heat exchanger 15, an accumulator 17, four-way valves 31 (example of "first switching valve") and 32 (example of "second switching valve"), piping 63 (example of "third piping"), 64 (example of "fourth piping"), 65 and 66, and an auxiliary heat exchanger 301. The outdoor heat exchanger 15 has a third refrigerant inlet / outlet 53 and a fourth refrigerant inlet / outlet 54.

[0037] The following describes the refrigerant circuit 10, but the explanation of the piping connecting the components may be omitted.

[0038] During heating and defrosting operation, the refrigerant in the refrigerant circuit 10 circulates in the following order: compressor 11, branch pipe 12, four-way valve 32, indoor heat exchanger 13, auxiliary heat exchanger 301, expansion valve 14, expansion valve 18, auxiliary heat exchanger 301, accumulator 17 and compressor 11, as well as in the following order: compressor 11, branch pipe 12, four-way valve 31, outdoor heat exchanger 15, expansion valve 18, auxiliary heat exchanger 301, accumulator 17 and compressor 11.

[0039] The compressor 11 has a refrigerant discharge section 11a and a refrigerant intake section 11b. The compressor 11 draws in low-temperature, low-pressure gaseous refrigerant through the refrigerant intake section 11b, compresses the drawn-in refrigerant, generates high-temperature, high-pressure gaseous refrigerant, and discharges it from the refrigerant discharge section 11a.

[0040] The branch pipe 12 distributes the refrigerant discharged from the refrigerant discharge section 11a to the four-way valves 31 and 32. More specifically, the branch pipe 12 connects the refrigerant discharge section 11a with the four-way valves 31 and 32. More specifically, the branch pipe 12 has a first port connected to the refrigerant discharge section 11a, a second port connected to the four-way valve 31, and a third port connected to the four-way valve 32.

[0041] The four-way valve 31 switches the connection state between the outdoor heat exchanger 15 and the compressor 11. More specifically, the four-way valve 31 connects the third refrigerant inlet / outlet 53 to either the refrigerant discharge section 11a or the refrigerant suction section 11b. In other words, the four-way valve 31 switches between a state where the third refrigerant inlet / outlet 53 and the refrigerant discharge section 11a are connected, and a state where the third refrigerant inlet / outlet 53 and the refrigerant suction section 11b are connected. During heating and defrosting operation, the four-way valve 31 connects the third refrigerant inlet / outlet 53 to the refrigerant discharge section 11a.

[0042] In this embodiment, since only three of the four ports of the four-way valve 31 are used, it may be composed of a three-way valve. Specifically, the four-way valve 31 has a first port connected to the second port of the branch pipe 12, a second port connected to the third refrigerant inlet / outlet 53, a third port connected to the branch pipe 16, and a closed fourth port.

[0043] During heating and defrosting operation, the four-way valve 31 connects the first and second ports, and also connects the third and fourth ports.

[0044] The four-way valve 32 switches the connection state between the indoor heat exchanger 13 and the compressor 11. More specifically, the four-way valve 32 connects the first refrigerant inlet / outlet 51 to either the refrigerant discharge section 11a or the refrigerant suction section 11b. In other words, the four-way valve 32 switches between a state where the first refrigerant inlet / outlet 51 and the refrigerant discharge section 11a are connected, and a state where the first refrigerant inlet / outlet 51 and the refrigerant suction section 11b are connected. During heating and defrosting operation, the four-way valve 32 connects the first refrigerant inlet / outlet 51 to the refrigerant discharge section 11a.

[0045] In this embodiment, since only three of the four ports of the four-way valve 32 are used, it may be composed of a three-way valve. More specifically, the four-way valve 32 has a first port connected to the third port of the branch pipe 12, a second port connected to the first refrigerant inlet / outlet 51, a third port connected to the branch pipe 16, and a closed fourth port.

[0046] During heating and defrosting operation, the four-way valve 32 connects the first and second ports, and also connects the third and fourth ports.

[0047] The branch pipe 16 connects the refrigerant intake section 11b with the four-way valve 31 and the four-way valve 32. More specifically, the branch pipe 16 has a first port connected to the refrigerant intake section 11b through a part of the piping 65 and the accumulator 17, a second port connected to the third port of the four-way valve 31, and a third port connected to the third port of the four-way valve 32.

[0048] During heating and defrosting operation, the second and third ports of the branch pipe 16 are connected to the fourth port of the four-way valve 31 and the fourth port of the four-way valve 32, respectively, which are closed, so no refrigerant flows through the branch pipe 16.

[0049] The indoor heat exchanger 13 includes a gas header 13a, a heat exchange section 13b, a distributor 13c, and a fan 13d.

[0050] The gas header 13a includes a first refrigerant inlet / outlet 51 (an example of a "first gas-side refrigerant inlet / outlet"). The gas header 13a distributes the high-pressure gaseous refrigerant supplied from the compressor 11 through the branch pipe 12, the four-way valve 32, and the first refrigerant inlet / outlet 51 to a plurality of branch pipes.

[0051] The heat exchange section 13b includes, for example, a plurality of heat transfer tubes connected to a plurality of branch tubes in the gas header 13a. Fins, for example, are connected to the plurality of heat transfer tubes.

[0052] During heating and defrosting operation, the fan 13d rotates to draw indoor air into the indoor unit 1 and discharges the air that has passed through the heat exchange section 13b to the outside of the indoor unit 1, i.e., into the room.

[0053] In the heat exchange tubes of the heat exchange section 13b, heat exchange takes place between the refrigerant supplied from the gas header 13a and the indoor air. As a result, the air heated by the heat exchange section 13b is blown into the room from the indoor unit 1. Also, inside the heat exchange tubes of the heat exchange section 13b, the temperature of the refrigerant decreases due to heat exchange, and it undergoes a phase change from a gaseous state to a liquid state.

[0054] The distributor 13c includes a second refrigerant inlet / outlet 52 (an example of a "first liquid-side refrigerant inlet / outlet") and a plurality of flow rate adjustment throttles connected to a plurality of heat transfer tubes in the heat exchange section 13b. The distributor 13c, for example, combines the liquid refrigerant flowing in from the heat exchange section 13b through the plurality of throttles and supplies it to the auxiliary heat exchanger 301 through the second refrigerant inlet / outlet 52 and piping 66.

[0055] The outdoor heat exchanger 15 includes a gas header 15a, a heat exchange section 15b, a distributor 15c, and a fan 15d.

[0056] The gas header 15a includes a third refrigerant inlet / outlet 53 (an example of a "second gas-side refrigerant inlet / outlet"). The gas header 15a distributes the high-pressure gaseous refrigerant supplied from the compressor 11 through the branch pipe 12, the four-way valve 31, and the third refrigerant inlet / outlet 53 to a plurality of branch pipes.

[0057] The heat exchange section 15b includes, for example, a plurality of heat transfer tubes connected to a plurality of branch tubes in the gas header 15a. Fins, for example, are connected to the plurality of heat transfer tubes.

[0058] Fan 15d is stopped during heating and defrosting operation. In the heat exchange section 15b, heat exchange takes place between the refrigerant in the heat transfer tubes and the frost adhering to the heat transfer tubes and fins. As a result, the frost is heated and turns into liquid water, which is then removed from the heat exchange section 15b. Also, inside the heat transfer tubes in the heat exchange section 15b, the refrigerant's temperature decreases due to heat exchange, and it undergoes a phase change from a gaseous state to a liquid state.

[0059] The distributor 15c includes a fourth refrigerant inlet / outlet 54 (an example of a "second liquid-side refrigerant inlet / outlet") and a plurality of flow rate adjustment throttles connected to a plurality of heat transfer tubes in the heat exchange section 15b. The distributor 15c, for example, combines the liquid refrigerant flowing in from the heat exchange section 15b through the plurality of throttles and supplies it to the piping 63 through the fourth refrigerant inlet / outlet 54.

[0060] The auxiliary heat exchanger 301 includes piping 61 (an example of "first piping") and 62 (an example of "second piping"). Piping 61 has one end connected to the second refrigerant inlet / outlet 52 through piping 66 and the other end on the expansion valve 14 side. Piping 62 has one end connected to the refrigerant suction section 11b through piping 65 and the accumulator 17 and the other end on the expansion valve 18 side. The auxiliary heat exchanger 301 causes heat exchange between the refrigerants flowing through piping 61 and 62, respectively.

[0061] Piping 63 connects the other end of piping 61 to the fourth refrigerant inlet / outlet 54. The expansion valve 14 is provided in piping 63.

[0062] In detail, piping 63 includes piping 63a and 63b. Piping 63b has one end connected to the other end of piping 61 and the other end connected to one end of the expansion valve 14. Piping 63a has one end connected to the fourth refrigerant inlet / outlet 54 and the other end connected to the other end of the expansion valve 14.

[0063] Pipe 64 connects the other end of pipe 62 to pipe 63. In this embodiment, pipe 64 connects the other end of pipe 62 to the space between the expansion valve 14 and the fourth refrigerant inlet / outlet 54 in pipe 63. That is, pipe 64 connects the other end of pipe 62 to pipe 63a.

[0064] The expansion valve 14 is slightly restricted during heating and defrosting operation. This limits the flow rate of refrigerant from piping 63b to piping 63a. As the refrigerant passes through the expansion valve 14, the refrigerant pressure decreases. In piping 63a, the refrigerant is in a liquid state.

[0065] The expansion valve 18 is installed in the piping 64. The expansion valve 18 is opened slightly during heating and defrosting operation.

[0066] When the refrigerant passes through the expansion valve 18, the pressure of the refrigerant decreases. At this time, some of the refrigerant may gasify.

[0067] In the auxiliary heat exchanger 301, the temperature of the refrigerant in piping 61 is higher than the temperature of the refrigerant in piping 62.

[0068] The refrigerant supplied from the expansion valve 18 to the piping 62 is heated by heat exchange with the refrigerant flowing through the piping 61. As a result, the refrigerant undergoes a phase change, mostly from a liquid state to a gaseous state.

[0069] In other words, during heating and defrosting operation, the auxiliary heat exchanger 301 functions as an evaporator. This makes it easier for high-temperature refrigerant to flow to the outdoor heat exchanger 15, thereby shortening the time required for defrosting the outdoor heat exchanger 15.

[0070] The refrigerant is drawn from the piping 62 to the refrigerant intake 11b of the compressor 11 through the accumulator 17 by the negative pressure of the compressor 11. At this time, even if a portion of the refrigerant is in a liquid state, this portion is accumulated in the accumulator 17, so that gaseous refrigerant is drawn into the refrigerant intake 11b of the compressor 11. This suppresses the return of liquid to the compressor 11, thereby reducing the load on the compressor 11 and preventing malfunction or damage.

[0071] [During heating operation] Figure 2 is a diagram showing an overview of the air conditioning system 101 according to this embodiment during heating operation. As shown in Figure 2, during heating operation, the refrigerant circulates in the refrigerant circuit 10 in the following order: compressor 11, branch pipe 12, four-way valve 32, indoor heat exchanger 13, auxiliary heat exchanger 301, expansion valve 14, outdoor heat exchanger 15, four-way valve 31, branch pipe 16, accumulator 17, and compressor 11.

[0072] During heating operation, the four-way valve 31 connects the third refrigerant inlet / outlet 53 to the refrigerant suction section 11b.

[0073] In detail, the four-way valve 31 connects the first port and the fourth port, and also connects the second port and the third port, during heating operation.

[0074] During heating operation, the second port of the branch pipe 12 is connected to the fourth port of the closed four-way valve 31, so no refrigerant flows through the second port of the branch pipe 12.

[0075] During heating operation, the four-way valve 32 connects the first refrigerant inlet / outlet 51 to the refrigerant discharge section 11a.

[0076] In detail, the four-way valve 32 connects the first and second ports, and also connects the third and fourth ports, during heating operation.

[0077] During heating operation, the third port of the branch pipe 16 is connected to the fourth port of the four-way valve 32, which is closed, so no refrigerant flows through the third port of the branch pipe 16.

[0078] The gas header 13a in the indoor heat exchanger 13 distributes the high-pressure gaseous refrigerant supplied from the compressor 11 through the branch pipe 12, the four-way valve 32, and the first refrigerant inlet / outlet 51 to multiple branch pipes.

[0079] During heating operation, the fan 13d rotates to draw indoor air into the indoor unit 1 and discharges the air that has passed through the heat exchange section 13b to the outside of the indoor unit 1, i.e., into the room.

[0080] In the heat exchange tubes of the heat exchange section 13b, heat exchange takes place between the refrigerant supplied from the gas header 13a and the indoor air. As a result, the air heated by the heat exchange section 13b is blown into the room from the indoor unit 1. Also, inside the heat exchange tubes of the heat exchange section 13b, the temperature of the refrigerant decreases due to heat exchange, and it undergoes a phase change from a gaseous state to a liquid state.

[0081] The distributor 13c combines the liquid refrigerant supplied from the heat exchange unit 13b through multiple throttling sections, for example, and supplies it to the auxiliary heat exchanger 301 through the second refrigerant inlet / outlet 52 and piping 66.

[0082] The expansion valve 14 is slightly restricted during heating operation. As a result, when the refrigerant supplied from the auxiliary heat exchanger 301 passes through the expansion valve 14, the refrigerant pressure decreases and the refrigerant temperature decreases. In piping 63a, the refrigerant is in a two-phase state, consisting of a gaseous state and a liquid state.

[0083] The expansion valve 18 closes during heating operation. As a result, refrigerant does not flow through parts of the piping 64, 62, and 65, and therefore almost no heat exchange occurs in the auxiliary heat exchanger 301.

[0084] In the outdoor heat exchanger 15, the distributor 15c distributes the refrigerant supplied from the piping 63a through the fourth refrigerant inlet / outlet 54 to multiple throttle sections. In each of the multiple throttle sections, the liquid volume of the refrigerant is equalized, and the refrigerant is supplied to each heat transfer tube in the heat exchange section 15b.

[0085] During heating operation, the fan 15d rotates to draw in outside air into the outdoor unit 2 and discharges the air that has passed through the heat exchange section 15b to the outside of the outdoor unit 2.

[0086] In the heat exchange tubes of the heat exchange section 15b, heat exchange takes place between the refrigerant supplied from the distributor 15c and the outdoor air. Inside the heat exchange tubes of the heat exchange section 15b, the refrigerant undergoes a phase change from a two-phase state of gaseous and liquid states to a gaseous state due to heat exchange. The air cooled by the heat exchange section 15b is then blown outside from the outdoor unit 2.

[0087] The gas header 15a brings together the gaseous refrigerant supplied from multiple heat transfer tubes in the heat exchange section 15b via branch pipes.

[0088] The refrigerant is drawn in by the negative pressure of the compressor 11 from the third refrigerant inlet / outlet 53 through the four-way valve 31, the branch pipe 16, and the accumulator 17 to the refrigerant suction section 11b of the compressor 11.

[0089] When switching from heating operation to heating defrosting operation, the opening of the expansion valve 18 occurs before or simultaneously with the switching operation of the four-way valve 31. On the other hand, when switching from heating defrosting operation to heating operation, the switching operation of the four-way valve 31 occurs before or simultaneously with the closing operation of the expansion valve 18.

[0090] [During cooling operation] Figure 3 is a diagram showing an overview of the air conditioning system 101 according to this embodiment during cooling operation. As shown in Figure 3, during cooling operation, the refrigerant circulates in the refrigerant circuit 10 in the following order: compressor 11, branch pipe 12, four-way valve 31, outdoor heat exchanger 15, expansion valve 14, auxiliary heat exchanger 301, indoor heat exchanger 13, four-way valve 32, branch pipe 16, accumulator 17, and compressor 11.

[0091] During cooling operation, the connection state of the four-way valve 31 is the same as the connection state of the four-way valve 31 during heating and defrosting operation. During cooling operation, the four-way valve 31 connects the third refrigerant inlet / outlet 53 to the refrigerant discharge section 11a.

[0092] In detail, the four-way valve 31 connects the first and second ports, and also connects the third and fourth ports, during cooling operation.

[0093] During cooling operation, the second port of the branch pipe 16 is connected to the fourth port of the four-way valve 31, which is blocked, so no refrigerant flows through the second port of the branch pipe 16.

[0094] During cooling operation, the four-way valve 32 connects the first refrigerant inlet / outlet 51 to the refrigerant suction section 11b.

[0095] In detail, the four-way valve 32 connects the first port and the fourth port, and also connects the second port and the third port, during cooling operation.

[0096] During cooling operation, the third port of the branch pipe 12 is connected to the fourth port of the four-way valve 32, which is blocked, so no refrigerant flows through the third port of the branch pipe 12.

[0097] The gas header 15a in the outdoor heat exchanger 15 distributes the high-pressure gaseous refrigerant supplied from the compressor 11 through the branch pipe 12, the four-way valve 31, and the third refrigerant inlet / outlet 53 to multiple branch pipes.

[0098] During cooling operation, the fan 15d rotates to draw in outside air into the outdoor unit 2 and discharges the air that has passed through the heat exchange section 15b to the outside of the outdoor unit 2.

[0099] In the heat exchange tubes of the heat exchange section 15b, heat exchange takes place between the refrigerant supplied from the gas header 15a and the outdoor air. Inside the heat exchange tubes of the heat exchange section 15b, the temperature of the refrigerant decreases due to the heat exchange, and it undergoes a phase change from a gaseous state to a liquid state. The air heated by the heat exchange section 15b is then blown outside from the outdoor unit 2.

[0100] The distributor 15c combines the refrigerant supplied from the heat exchange unit 15b through multiple throttling sections and supplies it to the piping 63a.

[0101] The expansion valve 18 closes during cooling operation. As a result, refrigerant does not flow through parts of the piping 64, 62, and 65, and therefore almost no heat exchange occurs in the auxiliary heat exchanger 301.

[0102] The expansion valve 14 is slightly restricted during cooling operation. As a result, when the refrigerant supplied from piping 63a passes through the expansion valve 14, the refrigerant pressure decreases and the refrigerant temperature decreases. In piping 63b, 61, and 66, the refrigerant is in a two-phase state, consisting of a gaseous state and a liquid state.

[0103] In the indoor heat exchanger 13, the distributor 13c distributes the refrigerant supplied from the piping 66 through the second refrigerant inlet / outlet 52 to multiple throttle sections. In each of the multiple throttle sections, the liquid volume of the refrigerant is equalized, and the refrigerant is supplied to each heat transfer tube in the heat exchange section 13b.

[0104] During cooling operation, the fan 13d rotates to draw indoor air into the indoor unit 1 and discharges the air that has passed through the heat exchange section 13b to the outside of the indoor unit 1, i.e., into the room.

[0105] In the heat exchange tubes of the heat exchange section 13b, heat exchange takes place between the refrigerant supplied from the distributor 13c and the indoor air. As a result, the air cooled by the heat exchange section 13b is blown into the room from the indoor unit 1. Inside the heat exchange tubes of the heat exchange section 13b, the refrigerant undergoes a phase change from a two-phase state of gaseous and liquid states to a gaseous state due to heat exchange.

[0106] The gas header 13a brings together the gaseous refrigerant supplied from multiple heat transfer tubes in the heat exchange section 13b via branch pipes.

[0107] The refrigerant is drawn in by the negative pressure of the compressor 11 from the first refrigerant inlet / outlet 51 through the four-way valve 32, the branch pipe 16, and the accumulator 17 to the refrigerant suction section 11b of the compressor 11.

[0108] In this embodiment, a configuration in which an expansion valve 18 is provided in the piping 64 has been described, but the invention is not limited to this configuration. The piping 64 may be configured to have a two-way valve instead of an expansion valve 18. Preferably, the piping 64 may be configured to have a pressure reducing device in addition to the two-way valve. The two-way valve and the pressure reducing device may be separate components, or the two functions may be combined into a single pressure reducing two-way valve.

[0109] Furthermore, although this embodiment describes a configuration in which a four-way valve 31 is provided, the system is not limited to this configuration. Instead of the four-way valve 31, a three-way valve may be provided that connects the third refrigerant inlet / outlet 53 to either the refrigerant discharge section 11a or the refrigerant suction section 11b.

[0110] Furthermore, although this embodiment describes a configuration in which a four-way valve 32 is provided, the system is not limited to this configuration. Instead of the four-way valve 32, a three-way valve may be provided that connects the first refrigerant inlet / outlet 51 to either the refrigerant discharge section 11a or the refrigerant suction section 11b.

[0111] Furthermore, although this embodiment describes a configuration in which pipe 64 connects the other end of pipe 62 to pipe 63a, it is not limited to this configuration. Pipe 64 may also be configured to connect the other end of pipe 62 to pipe 63b, i.e., between the auxiliary heat exchanger 301 and the expansion valve 14 in pipe 63.

[0112] In addition, in this embodiment, a throttle valve (not shown) may be provided between the connection point of pipe 64 and pipe 63 and the fourth refrigerant inlet / outlet 54 of the outdoor heat exchanger 15.

[0113] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The elements, arrangement, materials, conditions, shapes, and sizes of the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, it is possible to partially substitute or combine the configurations shown in different embodiments. [Explanation of symbols]

[0114] 1…Indoor unit 2…Outdoor unit 10…Refrigerant circuit 11… Compressor 11a...refrigerant discharge part 11b... Refrigerant intake 12... Branch pipe 13…Indoor heat exchanger 13a... Gas header 13b...Heat exchange section 13c…Distributor 13d...fan 14…Expansion valve 15...Outdoor heat exchanger 15a...Gas header 15b...Heat exchange section 15c…Distributor 15d...fan 16... Branch pipe 17... Accumulator 18…Expansion valve 31, 32... Four-way valve 51...First refrigerant inlet / outlet 52...Second refrigerant inlet / outlet 53...Third refrigerant inlet / outlet 54…Fourth refrigerant inlet / outlet 61, 62, 63, 63a, 63b, 64, 65, 66… Piping 101... Air conditioning system 301…Auxiliary heat exchanger

Claims

1. A compressor having a discharge section and a suction section, An indoor heat exchanger having a first refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a An outdoor heat exchanger having a third refrigerant inlet and a fourth refrigerant inlet and a A second switching valve that connects the first refrigerant inlet / outlet to either the discharge section or the suction section, A first switching valve that connects the third refrigerant inlet / outlet to either the discharge section or the suction section without going through the second switching valve, An auxiliary heat exchanger comprising a first pipe having one end and the other end connected to the second refrigerant inlet / outlet, and a second pipe having one end and the other end connected to the suction section, wherein heat exchange occurs between the refrigerant flowing through the first pipe and the second pipe, respectively. A third pipe connecting the other end of the first pipe to the fourth refrigerant inlet / outlet, A fourth pipe connecting the other end of the second pipe to the third pipe, An expansion valve provided in the third pipe, The fourth pipe is provided with a two-way valve, Air conditioning system.

2. The fourth pipe connects the other end of the second pipe to the expansion valve and the fourth refrigerant inlet / outlet in the third pipe. The air conditioning device according to claim 1.

3. When switching from heating operation to heating defrost operation, The opening operation of the two-way valve is performed before or simultaneously with the switching operation of the first switching valve. The air conditioning device according to claim 1.

4. When switching from heating / defrosting operation to heating operation, The switching operation of the first switching valve is performed before or simultaneously with the closing operation of the two-way valve. The air conditioning device according to claim 1.

5. The aforementioned air conditioning system, The fourth pipe further includes a pressure reducer, The air conditioning device according to claim 1.

6. During heating and defrosting operation, the first and second switching valves connect the third refrigerant inlet / outlet and the first refrigerant inlet / outlet to the discharge section, respectively. The two-way valve opens during the heating and defrosting operation. The air conditioning device according to claim 1.

7. The temperature of the refrigerant in the first pipe is higher than the temperature of the refrigerant in the second pipe. The air conditioning device according to claim 6.

8. The first switching valve, during heating operation, connects the third refrigerant inlet / outlet to the suction section. The second switching valve, during the heating operation, connects the first refrigerant inlet / outlet to the discharge section. The two-way valve closes during the heating operation. The air conditioning device according to claim 1.

9. The first switching valve, during cooling operation, connects the third refrigerant inlet / outlet to the discharge section. The second switching valve, during the cooling operation, connects the first refrigerant inlet / outlet to the suction section. The two-way valve closes during the cooling operation. The air conditioning device according to claim 1.

10. A compressor having a discharge section and a suction section, An indoor heat exchanger having a first refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a An outdoor heat exchanger having a third refrigerant inlet and a fourth refrigerant inlet and a A first switching valve that connects the third refrigerant inlet / outlet to either the discharge section or the suction section, A second switching valve that connects the first refrigerant inlet / outlet to either the discharge section or the suction section, An auxiliary heat exchanger comprising a first pipe having one end and the other end connected to the second refrigerant inlet / outlet, and a second pipe having one end and the other end connected to the suction section, wherein heat exchange occurs between the refrigerant flowing through the first pipe and the second pipe, respectively. A third pipe connecting the other end of the first pipe to the fourth refrigerant inlet / outlet, A fourth pipe connecting the other end of the second pipe to the third pipe, An expansion valve provided in the third pipe, The fourth pipe is provided with a two-way valve, During heating and defrosting operation, which involves defrosting while maintaining heating, the connection state of the first switching valve is the same as the connection state of the first switching valve during cooling operation. Air conditioning system.

11. A compressor having a discharge section and a suction section, An indoor heat exchanger having a first refrigerant inlet and a second refrigerant inlet and a second refrigerant inlet and a An outdoor heat exchanger having a third refrigerant inlet and a fourth refrigerant inlet and a A first switching valve that connects the third refrigerant inlet / outlet to either the discharge section or the suction section, A second switching valve that connects the first refrigerant inlet / outlet to either the discharge section or the suction section, An auxiliary heat exchanger comprising a first pipe having one end and the other end connected to the second refrigerant inlet / outlet, and a second pipe having one end and the other end connected to the suction section, wherein heat exchange occurs between the refrigerant flowing through the first pipe and the second pipe, respectively. A third pipe connecting the other end of the first pipe to the fourth refrigerant inlet / outlet, A fourth pipe connecting the other end of the second pipe to the third pipe, An expansion valve provided in the third pipe, The fourth pipe is provided with a two-way valve, The fourth pipe connects the other end of the second pipe to the expansion valve and the fourth refrigerant inlet / outlet in the third pipe. Air conditioning system.

12. Compressor and, Indoor heat exchanger, Outdoor heat exchanger, A first switching valve for switching the connection state between the outdoor heat exchanger and the compressor, The system includes a second switching valve for switching the connection state between the indoor heat exchanger and the compressor, During heating and defrosting operation, which involves defrosting while maintaining heating, the connection state of the first switching valve is the same as the connection state of the first switching valve during cooling operation. Air conditioning system.

13. The compressor has a discharge section and a suction section, The indoor heat exchanger has a first gas-side refrigerant inlet and outlet, The outdoor heat exchanger has a second gas-side refrigerant inlet / outlet, The first switching valve switches between a state in which the second gas-side refrigerant inlet / outlet and the discharge section are connected, and a state in which the second gas-side refrigerant inlet / outlet and the suction section are connected. The second switching valve switches between a state in which the first gas-side refrigerant inlet / outlet and the discharge section are connected, and a state in which the first gas-side refrigerant inlet / outlet and the suction section are connected. The air conditioning device according to claim 12.

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