Auxiliary evaporator

Abstract

The present invention provides an auxiliary evaporator that can suppress increases in volume, mass, and cost, and suppress the time required for the refrigerant temperature to rise. [Solution] The auxiliary evaporator is used in an air conditioning system that performs heating and defrosting operations, and comprises a first cylindrical portion having a first internal space through which refrigerant supplied from the discharge section of the compressor through an indoor heat exchanger flows, and a second cylindrical portion having a second internal space through which the first cylindrical portion passes, and a flow space formed between the outer circumferential surface of the first cylindrical portion and the inner circumferential surface of the second cylindrical portion, wherein the refrigerant that has flowed through the first internal space and the refrigerant supplied from the discharge section through an outdoor heat exchanger flow through a pressure reducer and the flow space and are drawn into the suction section of the compressor.

Description

Technical Field

[0001] The present invention relates to an auxiliary evaporator.

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 device 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 device (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the air conditioner described in Patent Document 1, the heat storage device is provided with a heat storage material disposed on the outer periphery of the compressor and a heat storage heat exchange pipe penetrating the heat storage material. The heat storage material is formed of a mass of aluminum, and a heater is embedded therein.

[0005] However, because the heat storage heat exchange pipes and heaters are embedded in a block of aluminum, the volume and mass of the heat storage device increase, and the cost rises. In addition, since the heat from the heater is supplied to the refrigerant in the heat storage heat exchange pipes through the heat storage material, the time required to fill the heat storage material, which has a large heat capacity, with heat and raise the temperature of the refrigerant becomes longer.

[0006] Therefore, the present invention aims to provide an auxiliary evaporator that can suppress increases in volume, mass, and cost, and suppress the length of time required for the refrigerant temperature to rise. [Means for solving the problem]

[0007] An auxiliary evaporator according to one aspect of the present invention is an auxiliary evaporator used in an air conditioning system that performs heating and defrosting operations, comprising: a first cylindrical portion having a first internal space through which a refrigerant supplied from the discharge portion of a compressor through an indoor heat exchanger flows; and a second cylindrical portion having a second internal space through which the first cylindrical portion passes, wherein a flow space is formed between the outer circumferential surface of the first cylindrical portion and the inner circumferential surface of the second cylindrical portion, and the refrigerant that has flowed through the first internal space and the refrigerant supplied from the discharge portion through an outdoor heat exchanger are drawn into the suction portion of the compressor after flowing through a pressure reducer and the flow space.

[0008] Thus, in the configuration in which the refrigerant supplied from the compressor discharge through the indoor heat exchanger is used as the heat source, heat can be steadily supplied from the circulating refrigerant without the need to provide a large heat storage material to increase the heat capacity, thus suppressing an increase in the size of the auxiliary evaporator. Furthermore, in the configuration in which the first cylindrical part penetrates the second internal space of the second cylindrical part, and the refrigerant is circulated through the first internal space and the circulation space, the ratio of space to the volume of the auxiliary evaporator can be increased, thus suppressing an increase in mass. In addition, the materials required to form the auxiliary evaporator can be reduced, and a simpler structure can be achieved, thus suppressing an increase in cost. Moreover, since the heat capacity of the first cylindrical part can be reduced, the temperature of the first cylindrical part can be rapidly increased by the refrigerant circulating in the first internal space of the first cylindrical part. This suppresses an increase in the time required for the temperature of the refrigerant circulating in the circulation space to rise. Therefore, it is possible to provide an auxiliary evaporator that can suppress increases in volume, mass, and cost, and suppress an increase in the time required for the temperature of the refrigerant to rise.

[0009] In the above embodiment, the temperature of the refrigerant circulating in the first internal space may be higher than the temperature of the refrigerant circulating in the circulation space.

[0010] According to this embodiment, for example, when heating the outside of the second cylindrical portion, heat can be efficiently supplied to the refrigerant circulating in the circulation space from both the inside and outside of the circulation space.

[0011] In the above embodiment, the first cylindrical portion has the same inner diameter as the inner diameter of the piping connected to the indoor heat exchanger, and during cooling or heating operation, the refrigerant flows through the first internal space, but does not have to flow through the flow space.

[0012] According to this embodiment, the first cylindrical section of the auxiliary evaporator can be used as ordinary piping during cooling and heating operations. Furthermore, in an embodiment in which the inner diameter of the first cylindrical section and the inner diameter of the piping connected to the indoor heat exchanger are the same, the refrigerant can be smoothly circulated from the piping to the first internal space of the first cylindrical section.

[0013] In the above embodiment, the auxiliary evaporator may further include a heating element that contacts the outer circumferential surface of the second cylindrical portion.

[0014] Thus, by supplying heat to the refrigerant circulating in the circulation space from both the inside and outside of the refrigerant, the refrigerant in the circulation space can be heated efficiently.

[0015] In the above embodiment, the heating section may include an electric heater that spirally covers the outer circumferential surface of the second cylindrical section.

[0016] According to this embodiment, a heat source that contacts the entire outer surface of the second cylindrical portion can be easily mounted.

[0017] In the above embodiment, the first cylindrical portion and the second cylindrical portion extend along a first direction, and the auxiliary evaporator may further include a third cylindrical portion that extends along a second direction intersecting the first direction, penetrates the side surface of the second cylindrical portion and communicates with the flow space, and through which the refrigerant discharged from the flow space flows.

[0018] According to this embodiment, even if the cross-sectional size of the third cylindrical portion is large, the third cylindrical portion can be easily connected to the communication space. Furthermore, for example, by using a T-shaped pipe, the connection between the second cylindrical portion and the third cylindrical portion can be easily formed.

[0019] In the above aspect, the first cylindrical portion and the second cylindrical portion extend along a first direction, the auxiliary evaporator extends along a second direction intersecting the first direction, penetrates a side surface of the second cylindrical portion, and communicates with the flow space, and may further include a fourth cylindrical portion through which the refrigerant supplied to the flow space flows.

[0020] According to this aspect, even if the size of the cross-section of the fourth cylindrical portion is large, the fourth cylindrical portion can be easily communicated with the communication space. Further, for example, by using a T-shaped pipe, the connection portion between the second cylindrical portion and the fourth cylindrical portion can be easily formed.

[0021] In the above aspect, the flow direction of the refrigerant in the first internal space and the flow direction of the refrigerant in the flow space may be opposite to each other.

[0022] According to this aspect, since the inflow side of the first internal space becomes the outflow side of the flow space, the temperatures of the respective refrigerants on the inflow side of the first internal space and the outflow side of the flow space can be both increased. Since the outflow side of the first internal space becomes the inflow side of the flow space, the temperatures of the respective refrigerants on the outflow side of the first internal space and the inflow side of the flow space can be both decreased. Thereby, it is possible to suppress a large variation in the difference between the temperature of the refrigerant in the first internal space and the temperature of the refrigerant in the flow space depending on the location, so that the refrigerant in the flow space can be uniformly heated.

[0023] An auxiliary evaporator according to an aspect of the present invention is an auxiliary evaporator used in an air conditioner that performs a heating defrost operation, and includes a first cylindrical portion having a first internal space and a second cylindrical portion having a second internal space through which the first cylindrical portion penetrates. A flow space is formed between an outer peripheral surface of the first cylindrical portion and an inner peripheral surface of the second cylindrical portion, and a refrigerant supplied from a discharge portion of a compressor through an indoor heat exchanger flows through the flow space. The refrigerant flowing through the flow space and the refrigerant supplied from the discharge portion through an outdoor heat exchanger flow through a decompressor and the first internal space and are sucked into a suction portion of the compressor.

[0024] Thus, according to the mode in which the refrigerant supplied from the discharge part of the compressor through the indoor heat exchanger is used as a heat source, heat can be constantly supplied from the circulating refrigerant without providing a large-sized heat storage material to increase the heat capacity, so that an increase in the size of the auxiliary evaporator can be suppressed. And according to the mode in which the first cylindrical part penetrates through the second internal space of the second cylindrical part and the refrigerant is circulated in the first internal space and the circulation space, the ratio of the space to the volume of the auxiliary evaporator can be increased, so that an increase in mass can be suppressed. Further, the material required for forming the auxiliary evaporator can be reduced and a simple structure can be achieved, so that an increase in cost can be suppressed. In addition, since the heat capacity of the first cylindrical part can be reduced, the temperature of the first cylindrical part can be quickly increased by the refrigerant flowing through the circulation space. Thereby, it is possible to suppress an increase in the time required for the temperature of the refrigerant flowing through the first internal space to rise. Therefore, it is possible to provide an auxiliary evaporator capable of suppressing an increase in volume, mass, and cost and suppressing an increase in the time required for the temperature of the refrigerant to rise.

[0025] In the above mode, the temperature of the refrigerant flowing through the circulation space may be higher than the temperature of the refrigerant flowing through the first internal space.

[0026] Thus, according to the mode in which the refrigerant flowing through the first internal space is heated by a higher-temperature refrigerant flowing outside thereof, in the case of heating the outside of the second cylindrical part from the outside of the refrigerant at a low temperature, heat can be efficiently supplied to the refrigerant flowing through the first internal space.

Advantages of the Invention

[0027] According to the present invention, it is possible to provide an auxiliary evaporator capable of suppressing an increase in volume, mass, and cost and suppressing an increase in the time required for the temperature of the refrigerant to rise.

Brief Description of the Drawings

[0028] [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. [Figure 4] This is a side view of the auxiliary heat exchanger 301 according to this embodiment. [Figure 5] This is a cross-sectional view of the auxiliary heat exchanger 301 according to this embodiment. [Figure 6] This is a side view of auxiliary heat exchanger 302, which is a modified example of auxiliary heat exchanger 301. [Figure 7] This is a side view of the auxiliary heat exchanger 301 with a different connection configuration than the auxiliary heat exchanger 301 shown in Figure 4. [Figure 8] Figure 7 is a cross-sectional view of the auxiliary heat exchanger 301. [Modes for carrying out the invention]

[0029] 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.

[0030] [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.

[0031] 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.

[0032] The following describes the refrigerant circuit 10, but the explanation of the piping connecting the components may be omitted.

[0033] During heating operation and defrosting, 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] During heating and defrosting operation, the four-way valve 31 connects the first and second ports, and also connects the third and fourth ports.

[0039] 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.

[0040] 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.

[0041] During heating and defrosting operation, the four-way valve 32 connects the first and second ports, and also connects the third and fourth ports.

[0042] 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.

[0043] 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.

[0044] The indoor heat exchanger 13 includes a gas header 13a, a heat exchange section 13b, a distributor 13c, and a fan 13d.

[0045] The gas header 13a includes a first refrigerant inlet / outlet 51. The gas header 13a distributes 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The distributor 13c includes a second refrigerant inlet / outlet 52 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.

[0050] The outdoor heat exchanger 15 includes a gas header 15a, a heat exchange section 15b, a distributor 15c, and a fan 15d.

[0051] The gas header 15a includes a third refrigerant inlet / outlet 53. The gas header 15a distributes 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.

[0052] 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.

[0053] 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.

[0054] The distributor 15c includes a fourth refrigerant inlet / outlet 54 and a plurality of flow rate regulating 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] The expansion valve 18 is installed in the piping 64. The expansion valve 18 is opened slightly during heating and defrosting operation.

[0061] When the refrigerant passes through the expansion valve 18, the pressure of the refrigerant decreases. At this time, some of the refrigerant may gasify.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] [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.

[0067] During heating operation, the four-way valve 31 connects the third refrigerant inlet / outlet 53 to the refrigerant suction section 11b.

[0068] 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.

[0069] During heating operation, the second port of the branch pipe 12 is connected to the fourth port of the four-way valve 31, which is closed, so no refrigerant flows through the second port of the branch pipe 12.

[0070] During heating operation, the four-way valve 32 connects the first refrigerant inlet / outlet 51 to the refrigerant discharge section 11a.

[0071] In detail, the four-way valve 32 connects the first and second ports, and also connects the third and fourth ports, during heating operation.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] The gas header 15a brings together the gaseous refrigerant supplied from multiple heat transfer tubes in the heat exchange section 15b via branch pipes.

[0083] 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.

[0084] 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.

[0085] [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.

[0086] 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.

[0087] In detail, the four-way valve 31 connects the first and second ports, and also connects the third and fourth ports, during cooling operation.

[0088] 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.

[0089] During cooling operation, the four-way valve 32 connects the first refrigerant inlet / outlet 51 to the refrigerant suction section 11b.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] The distributor 15c combines the refrigerant supplied from the heat exchange unit 15b through multiple throttling sections and supplies it to the piping 63a.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] The gas header 13a brings together the gaseous refrigerant supplied from multiple heat transfer tubes in the heat exchange section 13b via branch pipes.

[0102] 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.

[0103] [Structure of auxiliary heat exchanger 301] The structure of the auxiliary heat exchanger 301 will be described below. Each drawing may show the X, Y, and Z axes. The X, Y, and Z axes form a three-dimensional Cartesian coordinate system in a right-handed system. Hereinafter, the direction of the arrow on the X axis may be called the X-axis+ side, and the direction opposite to the arrow may be called the X-axis- side, and the same applies to the other axes. The Z-axis+ side and Z-axis- side may also be called the "upper side" and "lower side," respectively. Furthermore, the planes perpendicular to the X, Y, or Z axes may be called the YZ plane, ZX plane, or XY plane, respectively.

[0104] Figure 4 is a side view of the auxiliary heat exchanger 301 according to this embodiment. Figure 5 is a cross-sectional view of the auxiliary heat exchanger 301 according to this embodiment.

[0105] As shown in Figures 4 and 5, the piping 61 (an example of the "first cylindrical section") in the auxiliary heat exchanger 301 (an example of the "auxiliary evaporator") extends along the X-axis direction (an example of the "first direction"). The piping 61 has a cylindrical shape. In this embodiment, the piping 61 has a cylindrical shape. However, the piping 61 may also have a rectangular cylindrical shape.

[0106] The piping 61 has a cylindrical internal space 161 (an example of the "first internal space") that extends along the X-axis.

[0107] The internal space 161 is through which the refrigerant supplied from the refrigerant discharge section 11a through the indoor heat exchanger 13 and piping 66 flows. In this embodiment, the refrigerant flows in the internal space 161 in the direction of the X-axis+.

[0108] The pipe 61 is formed of, for example, metal. In this embodiment, the pipe 61 is formed of a metal containing copper, which has good thermal conductivity. However, the pipe 61 may be formed of other types of metal or resin.

[0109] Furthermore, pipe 61 has the same inner diameter as pipe 66, which is connected to the indoor heat exchanger 13. Also, pipe 61 has the same inner diameter as pipe 63b. In other words, the inner circumferential surfaces of each pipe, including pipe 66, pipe 61, and pipe 63b, are smooth.

[0110] Specifically, pipes 63b and 66 may have, for example, a cylindrical shape. Pipe 61 may have the outer diameter of pipe 63b and pipe 66. For example, it may be formed by a single pipe spanning pipe 66, pipe 61 and pipe 63b.

[0111] The pipe 62 (an example of the "second cylindrical section") extends along the X-axis direction. The pipe 62 has a cylindrical shape. In this embodiment, the pipe 62 has a cylindrical shape. However, the pipe 62 may also have a rectangular cylindrical shape.

[0112] The piping 62 is an internal space 162 (an example of a "second internal space") that extends along the X-axis direction and has a cylindrical internal space 162 through which the piping 61 passes.

[0113] The pipe 62 is formed of, for example, metal. In this embodiment, the pipe 62 is formed of a metal containing copper. However, the pipe 62 may be formed of other types of metal or of resin.

[0114] In the central part of pipe 62, the inner surface of pipe 62 and the outer surface of pipe 61 (an example of an "outer surface") do not come into contact. As a result, a space (hereinafter sometimes referred to as the flow space 162a) is formed between the inner surface of pipe 62 and the outer surface of pipe 61.

[0115] On the other hand, the diameter of both ends of pipe 62 is narrowed so that the inner surface of pipe 62 is in contact with the outer surface of pipe 61. In other words, the outer diameter and inner diameter at both ends of pipe 62 are smaller than the outer diameter and inner diameter at the center.

[0116] At both ends of pipe 62, the inner surface of pipe 62 and the outer surface of pipe 61 are, for example, brazed together. As a result, both ends of pipe 62 are sealed, and the flow space 162a becomes a closed space.

[0117] The piping 64 (an example of the "fourth cylindrical section") extends along the Z-axis direction (an example of the "second direction"). The piping 64 has, for example, a cylindrical shape. The piping 64 penetrates the lower outer peripheral surface of the outer peripheral surface of the piping 62 and is brazed to the piping 62. This connects the internal space of the piping 64 with the flow space 162a, forming a refrigerant inlet.

[0118] The pipe 65 (an example of the "third cylindrical section") extends along the Z-axis direction. The pipe 65 has, for example, a cylindrical shape. The pipe 65 is provided on the X-axis side of the pipe 64. The pipe 65 penetrates the upper outer peripheral surface of the outer peripheral surface of the pipe 62 and is brazed to the pipe 62. This connects the internal space of the pipe 65 with the flow space 162a, forming a refrigerant outlet.

[0119] The pipes 62, 64, and 65 may be formed, for example, by joining two T-joints.

[0120] When the expansion valve 18 is open, that is, when heating and defrosting operation is being performed, refrigerant flowing upward through the piping 64 is supplied to the flow space 162a.

[0121] The refrigerant flowing from piping 64 into the flow space 162a flows in the direction of the X axis. That is, the direction of refrigerant flow in the internal space 161 and the direction of refrigerant flow in the flow space 162a are opposite to each other. However, these directions of flow may be the same.

[0122] Heat exchange occurs between the refrigerant circulating in the internal space 161 and the refrigerant circulating in the circulation space 162a through the metal constituting the piping 61. When heating and defrosting operation is performed, the refrigerant circulating in the circulation space 162a is heated by receiving heat from the high-temperature refrigerant circulating in the internal space 161.

[0123] The refrigerant heated in the flow space 162a is discharged upward from the flow space 162a through the piping 65.

[0124] [Variations in the structure] Figure 6 is a side view of an auxiliary heat exchanger 302, which is a modified example of the auxiliary heat exchanger 301. As shown in Figure 6, the auxiliary heat exchanger 302 further includes an electric heater 311 (an example of a "heating section") compared to the auxiliary heat exchanger 301.

[0125] The electric heater 311 is, for example, a linear sheath heater. The electric heater 311 is in contact with the outer surface of the pipe 62. More specifically, the electric heater 311 is wrapped around the outer surface of the pipe 62, spirally covering the outer surface of the pipe 62. The electric heater 311 may also be a heater of other shapes, such as a strip-shaped sheet heater.

[0126] The electric heater 311 is secured, for example, by a band. The electric heater 311 is covered with an insulating material (not shown), for example, glass cloth. This helps to suppress the amount of heat escaping from the auxiliary heat exchanger 301 to the outside.

[0127] In this configuration, by supplying heat to the refrigerant circulating in the circulation space 162a from both the refrigerant circulating inside the circulation space 162a and the electric heater 311 provided outside the circulation space 162a, the refrigerant in the circulation space 162a can be heated efficiently.

[0128] Although the description has shown the pipe 64 extending along the Z-axis, it is not limited to this configuration. The pipe 64 may extend along any direction, such as the Y-axis, as long as it intersects with the X-axis.

[0129] Furthermore, while we have described a configuration in which the piping 65 extends along the Z-axis direction, it is not limited to this configuration. The piping 65 may extend along any direction, such as the Y-axis direction, as long as it intersects with the X-axis direction.

[0130] [Variations of connection methods] Figure 7 is a side view of an auxiliary heat exchanger 301 with a different connection configuration than the auxiliary heat exchanger 301 shown in Figure 4. Figure 8 is a cross-sectional view of the auxiliary heat exchanger 301 shown in Figure 7.

[0131] As shown in Figures 7 and 8, in this modified example, pipes 63b and 66 penetrate the outer surface of pipe 62, instead of pipes 64 and 65, compared to the outer surface of pipe 62 shown in Figures 4 and 5.

[0132] Furthermore, in this modified example, pipes 65 and 64 are connected to both ends of pipe 61, instead of pipes 66 and 63b, as shown in Figures 4 and 5.

[0133] Refrigerant supplied from the refrigerant discharge section 11a of the compressor 11 through the indoor heat exchanger 13 flows through the circulation space 162a.

[0134] The refrigerant that has flowed through the flow space 162a and the refrigerant supplied from the refrigerant discharge section 11a through the outdoor heat exchanger 15 flow through the expansion valve 18 and the internal space 161 and are drawn into the refrigerant intake section 11b of the compressor 11.

[0135] The temperature of the refrigerant circulating in the circulation space 162a is higher than the temperature of the refrigerant circulating in the internal space 161.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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]

[0142] 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 161, 162… Interior space 162a…Distribution space 301, 302…Auxiliary heat exchanger 311… Electric heater

Claims

1. An auxiliary evaporator used in an air conditioning system that performs heating and defrosting operations, A first cylindrical section having a first internal space through which refrigerant supplied from the discharge section of the compressor through the indoor heat exchanger flows, The first cylindrical portion comprises a second cylindrical portion having a second internal space through which the first cylindrical portion passes, A flow space is formed between the outer circumferential surface of the first cylindrical portion and the inner circumferential surface of the second cylindrical portion. The refrigerant that has flowed through the first internal space and the refrigerant supplied from the discharge section through the outdoor heat exchanger are drawn into the suction section of the compressor via the pressure reducer and the flow space. Auxiliary evaporator.

2. The temperature of the refrigerant flowing through the first internal space is higher than the temperature of the refrigerant flowing through the flow space. The auxiliary evaporator according to claim 1.

3. The first cylindrical portion has the same inner diameter as the inner diameter of the piping connected to the indoor heat exchanger. During cooling or heating operation, the refrigerant flows through the first internal space, but does not flow through the flow space. The auxiliary evaporator according to claim 1.

4. The auxiliary evaporator is, The second cylindrical portion further comprises a heating portion that contacts the outer circumferential surface. The auxiliary evaporator according to claim 1.

5. The heating section includes an electric heater that spirally covers the outer surface of the second cylindrical section. The auxiliary evaporator according to claim 4.

6. The first cylindrical portion and the second cylindrical portion extend along the first direction, The aforementioned auxiliary evaporator is, The present invention further comprises a third cylindrical portion that extends along a second direction intersecting the first direction, penetrates the side surface of the second cylindrical portion and communicates with the flow space, and through which the refrigerant discharged from the flow space flows, The auxiliary evaporator according to claim 1.

7. The first cylindrical portion and the second cylindrical portion extend along the first direction, The auxiliary evaporator is, The present invention further comprises a fourth cylindrical portion that extends along a second direction intersecting the first direction, penetrates the side surface of the second cylindrical portion and communicates with the flow space, and through which the refrigerant supplied to the flow space flows, The auxiliary evaporator according to claim 1.

8. The direction of flow of the refrigerant in the first internal space and the direction of flow of the refrigerant in the flow space are opposite to each other. The auxiliary evaporator according to claim 1.

9. An auxiliary evaporator used in an air conditioning system that performs heating and defrosting operations, A first cylindrical portion having a first internal space, The first cylindrical portion comprises a second cylindrical portion having a second internal space through which the first cylindrical portion passes, A flow space is formed between the outer circumferential surface of the first cylindrical portion and the inner circumferential surface of the second cylindrical portion. In the aforementioned circulation space, refrigerant supplied from the compressor's discharge section through the indoor heat exchanger flows. The refrigerant that has flowed through the aforementioned flow space and the refrigerant supplied from the discharge section through the outdoor heat exchanger flow through the pressure reducer and the first internal space and are drawn into the suction section of the compressor. Auxiliary evaporator.

10. The temperature of the refrigerant flowing through the aforementioned flow space is higher than the temperature of the refrigerant flowing through the first internal space. The auxiliary evaporator according to claim 9.

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