Refrigeration cycle equipment

Abstract

The non-azeotropic refrigerant mixture containing liquid components, which flows out of the diverter, is directed to the evaporator. [Solution] The refrigeration cycle device 100 comprises a heat source heat exchanger 13 and a bridge circuit 40. The heat source heat exchanger 13 has a refrigerant inlet pipe 13a, a refrigerant outlet pipe 13b, a plurality of refrigerant paths 61, a diverter 50, and a merger 70. The bridge circuit 40 flows refrigerant R so that it always flows into the heat source heat exchanger 13 at the refrigerant inlet pipe 13a and out of the heat source heat exchanger 13 at the refrigerant outlet pipe 13b. The plurality of refrigerant paths 61 are connected to a plurality of diverter pipes 56 of the diverter 50 and a plurality of merger pipes 75 of the merger 70. The number of diverter pipes 56 is less than the number of merger pipes 75.

Description

Technical Field

[0001] The present disclosure relates to a refrigeration cycle apparatus having a heat exchanger that handles a zeotropic refrigerant mixture, in which a counterflow in which the flow direction of the zeotropic refrigerant mixture and air is opposite is realized in the heat exchanger.

Background Art

[0002] The refrigeration cycle apparatus disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-222362) has a bridge circuit. Such a bridge circuit may be mounted on a refrigeration cycle apparatus that handles a zeotropic refrigerant mixture. In this case, the bridge circuit functions so as to always keep the flow direction of the refrigerant flowing through the heat source heat exchanger the same regardless of whether the refrigeration cycle apparatus executes either cold heat utilization operation or warm heat utilization operation, thereby realizing counterflow in the heat source heat exchanger.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A diverter may be provided in the heat exchanger. In many cases, the diverter is installed at the refrigerant inlet of the heat exchanger used as an evaporator. The diverter distributes the low-pressure gas-liquid two-phase refrigerant flowing into the refrigerant inlet to a plurality of refrigerant paths of the heat exchanger, thereby making the evaporation of the low-pressure gas-liquid two-phase refrigerant in the heat exchanger uniform.

[0004] When the heat exchanger that always realizes counterflow functions as a condenser, the diverter diverts the high-pressure gas refrigerant flowing in from the refrigerant inlet to a plurality of refrigerant paths. Generally, the gas refrigerant undergoes a large pressure loss in the piping. Therefore, the plurality of diverter pipes that guide the high-pressure gas refrigerant after diversion need to be designed thick in order to reduce the pressure loss.

[0005] However, when a heat exchanger functions as an evaporator, low-pressure gas-liquid two-phase refrigerant containing heavy liquid components cannot achieve sufficient velocity when passing through multiple wide diversion pipes. As a result, the low-pressure gas-liquid two-phase refrigerant may not be able to reach the refrigerant path located at a higher position from the diversion device itself, which is located at a lower position. [Means for solving the problem]

[0006] The refrigeration cycle device in the first aspect comprises a four-way switching valve, a first heat exchanger, a second heat exchanger, and a refrigerant flow straightening unit. The four-way switching valve switches between first operation and second operation. The first heat exchanger has a refrigerant inlet pipe and a refrigerant outlet pipe. The first heat exchanger functions as a condenser in first operation and as an evaporator in second operation. The second heat exchanger functions as an evaporator in first operation and as a condenser in second operation. The refrigerant flow straightening unit causes the refrigerant to flow into the first heat exchanger at the refrigerant inlet pipe and out of the first heat exchanger at the refrigerant outlet pipe in both first and second operation. The first heat exchanger further comprises a heat exchanger body, a flow divider, and a merger. The heat exchanger body has a plurality of refrigerant paths through which the refrigerant passes. The flow divider divides the refrigerant into a plurality of refrigerant paths. The merger brings together the refrigerant from the plurality of refrigerant paths. A flow divider has a flow divider body and flow divider piping. The flow divider body has one inlet and multiple outlets. The one inlet is connected to the refrigerant inlet pipe. The multiple flow divider pipes each connect to multiple outlets and multiple refrigerant paths. A merger has multiple merger pipes and a merger body. The multiple merger pipes are connected to multiple refrigerant paths. The merger body is connected to all of the multiple merger pipes and the refrigerant outlet pipe. The number of multiple flow divider pipes is less than the number of multiple merger pipes.

[0007] In this configuration, the number of branch pipes is less than the number of merging pipes. Therefore, because there are fewer branch pipes, each branch pipe can be made wider within the limited space of the device. As a result, the resistance that the refrigerant experiences through the branch pipes can be reduced.

[0008] The refrigeration cycle apparatus of the second aspect is the refrigeration cycle apparatus of the first aspect, wherein a plurality of refrigerant paths include a lowest-level path and a highest-level path. The lowest-level path is located at the lowest height. The highest-level path is located at the highest height. The height of each of the multiple outlets is lower than the height of the lowest-level path.

[0009] In this configuration, the height of the outlet is lower than the height of the lowest path. Even if the diversion piping extending from the diversion unit body to the inlet of each refrigerant path is long, the refrigerant flowing through the diversion piping does not encounter significant resistance. Therefore, the refrigerant can rise through the diversion piping.

[0010] A refrigeration cycle device according to the third perspective is a refrigeration cycle device according to the first or second perspective, wherein the number of branch pipes is less than or equal to half the number of merging pipes.

[0011] In this configuration, the number of branch pipes is less than half the number of merging pipes. Therefore, the diameter of the merging pipes can be set to be effectively large, and the refrigerant flowing through the branch pipes does not encounter significant resistance. Consequently, the refrigerant can rise through the branch pipes.

[0012] The refrigeration cycle device of the fourth aspect is a refrigeration cycle device of any one of the first, third, or fourth aspects, wherein multiple refrigerant paths each have heat transfer tubes. The inner diameter of each of the multiple branch pipes is 80% or more and 120% or less of the inner diameter of the heat transfer tubes.

[0013] In this configuration, the inner diameter of the diversion pipe is 80% or more and 120% or less of the inner diameter of the heat transfer tube. Therefore, because the inner diameter of the diversion pipe is large, the refrigerant flowing through the diversion pipe does not experience significant resistance.

[0014] The refrigeration cycle device of the fifth perspective is a refrigeration cycle device of any one of the first to fourth perspectives, wherein the heat exchanger body has a plurality of refrigerant path inlets and a plurality of branching sections. The plurality of refrigerant path inlets are points where the refrigerant flows into the plurality of refrigerant paths. The plurality of branching sections are provided at any of the plurality of refrigerant path inlets. Each of the plurality of branching sections connects one of the plurality of diversion pipes to at least two of the plurality of refrigerant path inlets.

[0015] In this configuration, the refrigerant coming from the branch piping is distributed to at least two refrigerant path inlets at the branching point. Therefore, it is possible to supply refrigerant to multiple refrigerant paths while keeping the resistance of the branch piping low. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing the configuration of the refrigeration cycle device 100 according to the first embodiment. [Figure 2] This is a schematic diagram showing the configuration of the heat source heat exchanger 13. [Figure 3] This is a schematic diagram showing the configuration of the heat exchanger body 60. [Figure 4] This is a schematic diagram showing the counterflow between the refrigerant R and the airflow AF in the heat source heat exchanger 13. [Figure 5] This graph shows the temperature changes of the refrigerant R and airflow AF during cooling operation. [Figure 6] This graph shows the temperature changes of the refrigerant R and airflow AF during thermal energy utilization operation. [Figure 7] This is a schematic diagram showing the detailed structure of the heat source heat exchanger 13. [Figure 8] This is a schematic diagram showing the configuration of the refrigeration cycle device 100A according to the second embodiment. [Figure 9] This is a schematic diagram showing the configuration of the refrigeration cycle device 100B according to the third embodiment. [Modes for carrying out the invention]

[0017] <First Embodiment> (1) Overall Configuration FIG. 1 shows the configuration of a refrigeration cycle apparatus 100 according to the first embodiment. The refrigeration cycle apparatus 100 provides cold heat or hot heat obtained from a heat source to a user by circulating a refrigerant R. The refrigeration cycle apparatus 100 provides cold heat to the user in a cold heat utilization operation. The refrigeration cycle apparatus 100 provides hot heat to the user in a hot heat utilization operation. The refrigeration cycle apparatus 100 can be configured in the form of an air conditioner, a refrigerator, a freezer, a water heater, a floor heating device, etc. When the refrigeration cycle apparatus 100 is an air conditioner, the cold heat utilization operation and the hot heat utilization operation correspond to a cooling operation and a heating operation, respectively. The refrigeration cycle apparatus 100 includes a heat source unit 10, a utilization unit 20, and a connection pipe group 30.

[0018] (2) Detailed Configuration (2-1) Refrigerant R The refrigerant R is a zeotropic mixture refrigerant. A zeotropic mixture refrigerant is a refrigerant made by mixing a plurality of refrigerant components having different boiling points. The refrigerant R is, for example, R454C. R454C is a mixture of R32 and R-1234yf.

[0019] Zeotropic mixture refrigerants exhibit a significant temperature glide. The temperature glide is the range of temperature change shown by the refrigerant R during the evaporation or condensation process. During the evaporation process of the zeotropic mixture refrigerant, the low-boiling component evaporates first, and then the high-boiling component evaporates later. During the condensation process of the zeotropic mixture refrigerant, the high-boiling component condenses first, and then the low-boiling component condenses later. The presence of such a plurality of boiling points causes a large temperature glide.

[0020] (2-2) Heat Source Unit 10 The heat source unit 10 obtains cold heat or hot heat from air as a heat source. The heat source unit 10 includes a compressor 11, a four-way switching valve 12, a heat source heat exchanger 13, a heat source fan 14, a bridge circuit 40, a heat source expansion valve 15, an accumulator 16, a liquid shut-off valve 17, and a gas shut-off valve 18.

[0021] (2-2-1) Compressor 11 The compressor 11 has an intake pipe 11a and a discharge pipe 11b. The compressor 11 draws in refrigerant R in a low-pressure gas state from the intake pipe 11a, compresses the refrigerant R, and discharges the refrigerant R in a high-pressure gas state from the discharge pipe 11b.

[0022] (2-2-2) Four-way switching valve 12 The four-way switching valve 12 switches between cooling operation and heating operation by switching the direction of travel of the refrigerant R. When performing cooling operation, the four-way switching valve 12 realizes the connection shown by the solid line in Figure 1 and causes the refrigerant R to travel in the direction indicated by arrow CO. When performing heating operation, the four-way switching valve 12 realizes the connection shown by the dashed line in Figure 1 and causes the refrigerant R to travel in the direction indicated by arrow HO.

[0023] (2-2-3) Heat source heat exchanger 13 and heat source fan 14 (2-2-3-1) Function The heat source heat exchanger 13 performs heat exchange between the air, which is the heat source, and the refrigerant R, thereby allowing the refrigerant R to acquire cooling or heating. When operating for cooling, the heat source heat exchanger 13 functions as a condenser or heat radiator for the refrigerant R, allowing the refrigerant R to acquire cooling. When operating for heating, the heat source heat exchanger 13 functions as an evaporator or heat absorber for the refrigerant R, allowing the refrigerant R to acquire heating.

[0024] The heat source heat exchanger 13 has a refrigerant inlet pipe 13a and a refrigerant outlet pipe 13b. The refrigerant R enters the heat source heat exchanger 13 through the refrigerant inlet pipe 13a and exits the heat source heat exchanger 13 through the refrigerant outlet pipe 13b. The heat source fan 14 promotes heat exchange between the air and the refrigerant R by generating an airflow that passes through the heat source heat exchanger 13.

[0025] In the following, the term "condenser" may include the use of a refrigerant R as a heat exchanger without a phase transition, and the term "evaporator" may include the use of a refrigerant R as a heat absorber without a phase transition.

[0026] (2-2-3-2) structure Figure 2 shows the structure of the heat source heat exchanger 13. In addition to the refrigerant inlet pipe 13a and the refrigerant outlet pipe 13b, the heat source heat exchanger 13 includes a flow divider 50, a heat exchanger body 60, and a flow merging device 70.

[0027] The flow divider 50 has a flow divider body 51 to which the refrigerant inlet pipe 13a is connected, and a plurality of flow divider pipes 56 extending from the flow divider body 51. The flow divider body 51 has one inlet 53 and a plurality of outlets 54. The refrigerant inlet pipe 13a is connected to the inlet 53. The plurality of flow divider pipes 56 are connected to their respective outlets 54. The refrigerant R flowing into the refrigerant inlet pipe 13a is divided into the plurality of flow divider pipes 56.

[0028] The heat exchanger body 60 is the part that performs heat exchange between the refrigerant R and air. The heat exchanger body 60 has multiple refrigerant paths 61 through which the refrigerant R flows. The multiple refrigerant paths 61 include a lowest-level path 61L located at the lowest height and a highest-level path 61H located at the highest height. Each refrigerant path 61 has a refrigerant path inlet 62 and a refrigerant path outlet 63. The refrigerant path inlet 62 is where the refrigerant R flows into the refrigerant path 61. The refrigerant path outlet 63 is where the refrigerant R flows out of the refrigerant path 61. The multiple refrigerant path inlets 62 are connected to the flow distribution pipe 56 via multiple branching sections 64. The multiple branching sections 64 will be described later.

[0029] The merging unit 70 has multiple merging pipes 75 and a merging unit body 76. Each merging pipe 75 connects one refrigerant path outlet 63 to the merging unit body 76. The merging unit body 76 has an outlet pipe connection section 77 to which the refrigerant outlet pipe 13b is connected. The merging unit 70 merges the refrigerant R received from the multiple refrigerant paths 61 and discharges it to the refrigerant outlet pipe 13b. The number of branch pipes 56 is less than the number of merging pipes 75. Preferably, the number of branch pipes 56 is half or less the number of merging pipes 75.

[0030] Figure 3 shows the configuration of the heat exchanger body 60. The heat exchanger body 60 has a plurality of heat transfer tubes 65 and a plurality of fins 67. Each heat transfer tube 65 is inserted into the through-holes of all the fins 67. The ends of two adjacent heat transfer tubes 65 are connected by a U-shaped tube 66. One refrigerant path 61 is composed of a plurality of heat transfer tubes 65 and a plurality of U-shaped tubes 66. The inner diameter of the plurality of diversion pipes 56 in the diversion 50 is all 80% or more and 120% or less of the inner diameter of the heat transfer tubes 65.

[0031] (2-2-3-3)Countercurrent Figure 4 schematically illustrates the counterflow realized in the heat source heat exchanger 13 and the heat source fan 14. Counterflow means that the direction of travel of the refrigerant R is opposite to the direction of travel of the airflow AF. Realizing counterflow in the heat source heat exchanger 13 is important for heat exchange with the refrigerant R, which has a large temperature glide.

[0032] The refrigerant R flows into the heat source heat exchanger 13 from the refrigerant inlet pipe 13a, is divided by the flow divider 50, passes through multiple refrigerant paths 61, merges in the merger 70, and flows out of the heat source heat exchanger 13 from the refrigerant outlet pipe 13b. Each refrigerant path 61 has multiple heat transfer tubes 65, which include heat transfer tubes 65 located in the first row L1 on the side of the front end 671 of the fins of the heat source heat exchanger 13, and heat transfer tubes 65 located in the second row L2 on the side of the rear end 672 of the fins. After flowing in from the refrigerant inlet pipe 13a, the refrigerant R always passes first through the heat transfer tubes 65 in the first row L1, then through the heat transfer tubes 65 in the second row L2, and finally flows out from the refrigerant outlet pipe 13b. In other words, the refrigerant R travels in the -y direction from the side of the front end 671 of the fins to the side of the rear end 672 of the fins.

[0033] Meanwhile, the airflow AF generated by the heat source fan 14 travels in the +y direction from the rear end 672 of the fins to the front end 671 of the fins, passing between adjacent fins 67.

[0034] (2-2-4) Bridge circuit 40 Returning to Figure 1, the bridge circuit 40 is designed to ensure counterflow between the refrigerant R and the airflow AF in the heat source heat exchanger 13 at all times. Normally, in a refrigerant circuit without the bridge circuit 40, the direction of the refrigerant R flowing through the heat exchanger reverses each time the operation is switched between cooling and heating. In contrast, in the refrigeration cycle device 100 of this embodiment, the bridge circuit 40 ensures that the direction of travel of the refrigerant R in the heat source heat exchanger 13 is always the same, regardless of whether cooling or heating operation is performed. With the bridge circuit 40, regardless of whether the direction of travel of the refrigerant R is indicated by arrow CO or arrow HO, the refrigerant R always enters the heat source heat exchanger 13 at the refrigerant inlet pipe 13a and always exits the heat source heat exchanger 13 at the refrigerant outlet pipe 13b.

[0035] The bridge circuit 40 has a first node A, a second node B, a third node C, and a fourth node D. The first node A is connected to the refrigerant outlet pipe 13b. The second node B is connected to the compressor 11 via a four-way switching valve 12. The third node C is connected to the refrigerant inlet pipe 13a. The fourth node D is connected to the heat source expansion valve 15.

[0036] Furthermore, the bridge circuit 40 has a first flow path AB extending from the first node A to the second node B, a second flow path BC extending from the second node B to the third node C, a third flow path DC extending from the fourth node D to the third node C, and a fourth flow path AD extending from the first node A to the fourth node D.

[0037] The bridge circuit 40 includes a first check valve 41, a second check valve 42, a third check valve 43, and a fourth check valve 44. These check valves maintain the same direction of flow for the refrigerant R in the installed flow path and prevent backflow of the refrigerant R. The first check valve 41 is located in the first flow path AB and allows the refrigerant R to flow only in the direction from the first node A to the second node B. The second check valve 42 is located in the second flow path BC and allows the refrigerant R to flow only in the direction from the second node B to the third node C. The third check valve 43 is located in the third flow path DC and allows the refrigerant R to flow only in the direction from the fourth node D to the third node C. The fourth check valve 44 is located in the fourth flow path AD and allows the refrigerant R to flow only in the direction from the first node A to the fourth node D.

[0038] (2-2-5) Heat source expansion valve 15 The heat source expansion valve 15 reduces the pressure of the refrigerant R. The heat source expansion valve 15 is composed of an electrically operated valve whose opening degree can be adjusted. When the opening degree of the heat source expansion valve 15 is set to a small value, the amount of refrigerant R that can pass through the heat source expansion valve 15 decreases, and the pressure of the refrigerant R after passing through the heat source expansion valve 15 decreases.

[0039] (2-2-6) Accumulator 16 The accumulator 16 allows only the gaseous component of the refrigerant R to pass through by storing only the liquid component inside. The accumulator 16 is connected to the suction pipe 11a of the compressor 11 to prevent the liquid component of the refrigerant R from damaging the compressor 11.

[0040] (2-2-7) Liquid shut-off valve 17 and gas shut-off valve 18 The liquid shut-off valve 17 and the gas shut-off valve 18 are for manually blocking the movement of the refrigerant R. The liquid shut-off valve 17 and the gas shut-off valve 18 are opened and closed manually by the installer of the refrigeration cycle device 100.

[0041] (2-3) Unit 20 The utilization unit 20 provides the user with the cold or heat obtained from the heat source by the heat source unit 10. The utilization unit 20 has a utilization heat exchanger 23 and a utilization fan 24.

[0042] (2-3-1) Utilized heat exchanger 23 The utilization heat exchanger 23 provides cooling or heating to the user by exchanging heat with the refrigerant R, such as the air in the user's environment or the water used by the user. When operating for cooling, the utilization heat exchanger 23 functions as an evaporator for the refrigerant R, providing cooling to the user. When operating for heating, the utilization heat exchanger 23 functions as a condenser for the refrigerant R, providing heating to the user. As mentioned above, the term "condenser" here includes the use of the refrigerant R as a heat sink without a phase transition, and the term "evaporator" may include the use of the refrigerant R as a heat absorber without a phase transition.

[0043] (2-3-2) Fan 24 The utilization fan 24 is provided when the user utilizes cooling or heating through the air. The utilization fan 24 promotes heat exchange between the air and the refrigerant R by generating an airflow that passes through the utilization heat exchanger 23.

[0044] (2-4) Connecting piping group 30 The connecting piping group 30 constitutes a circulation path for the refrigerant R by connecting the heat source unit 10 and the utilization unit 20. The connecting piping group 30 includes a liquid connecting pipe 31 and a gas connecting pipe 32. The liquid connecting pipe 31 mainly allows the refrigerant R to pass through in a liquid state or a gas-liquid two-phase state. The liquid connecting pipe 31 connects the liquid shut-off valve 17 to the utilization heat exchanger 23. The gas connecting pipe 32 mainly allows the refrigerant R to pass through in a high-pressure gas state or a low-pressure gas state. The gas connecting pipe 32 connects the gas shut-off valve 18 to the utilization heat exchanger 23.

[0045] (3) Overall operation (3-1)Cold heat utilization operation When operating using refrigeration, the four-way switching valve 12 is connected as shown by the solid line in Figure 1, and the refrigerant R is directed in the direction indicated by the arrow CO.

[0046] The compressor 11 draws in refrigerant R in a low-pressure gas state from the suction pipe 11a and discharges refrigerant R in a high-pressure gas state from the discharge pipe 11b. The refrigerant R in the high-pressure gas state passes through the four-way switching valve 12 and reaches the second node B of the bridge circuit 40. After that, the refrigerant R passes through the second check valve 42 and reaches the third node C. After that, the refrigerant R enters the heat source heat exchanger 13 at the refrigerant inlet pipe 13a. The heat source heat exchanger 13 generates refrigerant R in a high-pressure liquid state by condensing the refrigerant R using the cold energy of the air. The refrigerant R in the high-pressure liquid state exits the heat source heat exchanger 13 from the refrigerant outlet pipe 13b and then reaches the first node A. After that, the refrigerant R passes through the fourth check valve 44 and reaches the fourth node D. After that, the refrigerant R in the high-pressure liquid state is depressurized at the heat source expansion valve 15 and becomes refrigerant R in a gas-liquid two-phase state. Subsequently, the refrigerant R passes through the liquid shut-off valve 17 and the liquid connecting pipe 31 and reaches the utilization heat exchanger 23. The utilization heat exchanger 23 provides the user with the cooling energy carried by the refrigerant R by evaporating the refrigerant R in a gas-liquid two-phase state, and also generates refrigerant R in a low-pressure gas state. After that, the refrigerant R passes sequentially through the gas connecting pipe 32, the gas shut-off valve 18, the four-way switching valve 12, and the accumulator 16, and is then drawn into the compressor 11 in the suction pipe 11a.

[0047] (3-2) Operation utilizing thermal energy When operating using thermal energy, the four-way switching valve 12 is connected as shown by the dashed line in Figure 1, and the refrigerant R is directed in the direction indicated by the arrow HO.

[0048] The compressor 11 draws in refrigerant R in a low-pressure gas state from the suction pipe 11a and discharges refrigerant R in a high-pressure gas state from the discharge pipe 11b. The refrigerant R in the high-pressure gas state passes sequentially through the four-way switching valve 12, the gas shut-off valve 18, and the gas connecting pipe 32 to reach the utilization heat exchanger 23. The utilization heat exchanger 23 condenses the refrigerant R in the high-pressure gas state, providing the user with the heat carried by the refrigerant R and generating refrigerant R in a high-pressure liquid state. Subsequently, the refrigerant R passes through the liquid connecting pipe 31 and the liquid shut-off valve 17 to reach the heat source expansion valve 15. Subsequently, the refrigerant R in the high-pressure liquid state is depressurized in the heat source expansion valve 15 to become a gas-liquid two-phase refrigerant R. Subsequently, the refrigerant R passes sequentially through the fourth node D, the third check valve 43, and the third node C. Subsequently, the refrigerant R enters the heat source heat exchanger 13 at the refrigerant inlet pipe 13a. The heat source heat exchanger 13 generates low-pressure gaseous refrigerant R by evaporating it using the heat of the air. The low-pressure gaseous refrigerant R exits the heat source heat exchanger 13 through the refrigerant outlet pipe 13b and then reaches the first node A. After that, the refrigerant R passes through the first check valve 41 and reaches the second node B. After that, the refrigerant R passes through the four-way switching valve 12 and the accumulator 16 in sequence and is then drawn into the compressor 11 in the suction pipe 11a.

[0049] (3-3) Effect of countercurrent in the heat source heat exchanger 13 Figures 5 and 6 show examples of temperature changes for the refrigerant R and airflow AF in the heat source heat exchanger 13. The horizontal axis represents the position y in the y direction. y1 is the position of the rear end 672 of the fin, and y2 is the position of the front end 671 of the fin. The vertical axis represents the temperature T of the refrigerant R and airflow AF. The numerical values ​​of temperature T shown are for illustrative purposes only.

[0050] Figure 5 shows the temperature change during cooling operation. This figure assumes that the heat source heat exchanger 13 is achieving counterflow of refrigerant R and airflow AF. The airflow AF moves from position y1 at the rear end 672 of the fin to position y2 at the front end 671 of the fin. On the other hand, the refrigerant R moves from position y2 at the front end 671 of the fin to position y1 at the rear end 672 of the fin.

[0051] The heat source heat exchanger 13 functions as a condenser. Within the heat source heat exchanger 13, the refrigerant R loses heat to the airflow AF. As a result, the temperature of the refrigerant R decreases as it moves from position y2 to position y1. Since the airflow AF receives heat from the refrigerant R, the temperature of the airflow AF increases as it moves from position y1 to position y2.

[0052] The temperature difference ΔT1 between the refrigerant R and the airflow AF at position y1, and the temperature difference ΔT2 between the refrigerant R and the airflow AF at position y2, are both sufficiently large. Therefore, heat transfer from the refrigerant R to the airflow AF is carried out without any problems throughout the entire area of ​​the heat source heat exchanger 13.

[0053] Figure 6 shows the temperature change during thermal energy utilization operation. The heat source heat exchanger 13 functions as an evaporator. As the refrigerant R in the heat source heat exchanger 13 receives heat from the airflow AF, the temperature of the airflow AF decreases as it moves from position y1 to position y2.

[0054] The refrigerant R receives heat from the airflow AF. Therefore, as the refrigerant R moves through the heat source heat exchanger 13, its temperature rises. In this figure, two types of temperature changes for the refrigerant R are shown.

[0055] The arrow Rn indicates the temperature change in the comparative example. In the comparative example, the bridge circuit 40 is not present in the refrigerant circuit, and it is assumed that the refrigerant R moves in the opposite direction to that of the cooling operation. In this case, the refrigerant R moves from position y1 at the rear end 672 of the fin to position y2 at the front end 671 of the fin, similar to the airflow AF.

[0056] The arrow Rc indicates the temperature change in the heat source heat exchanger 13 of this embodiment. The refrigerant circuit has a bridge circuit 40, and counterflow is achieved in the heat source heat exchanger 13, similar to the cooling operation. At this time, the refrigerant R moves in the opposite direction to the airflow AF, from position y2 of the front end 671 of the fin to position y1 of the rear end 672 of the fin.

[0057] In the comparative example indicated by arrow Rn, the temperature difference ΔT3 between the refrigerant R and the airflow AF at position y1 and the temperature difference ΔT4 between the refrigerant R and the airflow AF at position y2 are significantly different. The temperature difference ΔT4 is not large enough. This indicates that heat transfer from the airflow AF to the refrigerant R may be inhibited near the front end 671 of the fin.

[0058] On the other hand, in this embodiment indicated by arrow Rc, the temperature difference ΔT5 between the refrigerant R and the airflow AF at position y1 and the temperature difference ΔT6 between the refrigerant R and the airflow AF at position y2 are both sufficiently large. Therefore, it is understood that heat transfer from the airflow AF to the refrigerant R is carried out without hindrance throughout the entire area of ​​the heat source heat exchanger 13 according to this embodiment.

[0059] When using a refrigerant R that has a large temperature glide, such as a non-azeotropic mixed refrigerant, it tends to be difficult to ensure a sufficient temperature difference between the refrigerant R and the airflow AF at the outlet of the heat exchanger. If a small value such as a temperature difference ΔT4 occurs, the heat exchange performance of the heat source heat exchanger 13 deteriorates. This problem can be improved by installing a bridge circuit 40 to ensure counterflow between the refrigerant R and the airflow AF at all times in the heat source heat exchanger 13.

[0060] (3-4) Circulation volume of refrigerant R The circulation rate of refrigerant R in the refrigeration cycle device 100 varies depending on the operating conditions, fluctuating within a range from a minimum to a maximum value. In the refrigeration cycle device 100, the circulation rate of refrigerant R may be significantly lower than the minimum value. In both cooling and heating operation, the minimum circulation rate of refrigerant R in the refrigeration cycle device 100 is less than 35.00 kg / h.

[0061] (4) Detailed structure of the heat source heat exchanger 13 Figure 7 shows the detailed structure of the heat source heat exchanger 13. The refrigerant path inlet 62 of the lowest pass 61L is located at a height H1. The refrigerant path inlet 62 of the highest pass 61H is located at a height H2. The heights H0 of the multiple outlets 54 are all lower than the height H1 of the lowest pass 61L.

[0062] The heat exchanger body 60 has a plurality of branch sections 64. Each branch section 64 is composed of branched piping having, for example, one inlet and two outlets. Each branch section 64 is located at one of the plurality of refrigerant path inlets 62. Each branch section 64 connects one flow distribution pipe 56 to two refrigerant path inlets 62.

[0063] (5) Characteristics (5-1) The number of branch pipes 56 is less than the number of merging pipes 75. For example, the number of branch pipes 56 is less than half the number of merging pipes 75. Therefore, because the number of branch pipes 56 is small, each branch pipe 56 can be made wider within the limited space of the refrigeration cycle device 100. As a result, the resistance due to pressure loss experienced by the refrigerant R through the branch pipes 56 can be reduced.

[0064] (5-2) The height of the outlet 54 of the diversion device body 51 of the diversion device 50 is lower than the height H1 of the lowest pass 61L. Therefore, the diversion pipes 56 extending from the diversion device body 51 to each refrigerant pass inlet 62 are long. Even with such long diversion pipes 56, the refrigerant R flowing through the wide diversion pipes 56 does not encounter significant resistance. Therefore, the refrigerant R can rise through the diversion pipes 56.

[0065] (5-3) The inner diameter of the diversion pipe 56 is 80% or more and 120% or less of the inner diameter of the heat transfer tube 65. Therefore, because the inner diameter of the diversion pipe 56 is large, the refrigerant R flowing through the diversion pipe 56 does not experience significant resistance.

[0066] (5-4) The refrigerant R coming from the diversion pipe 56 is distributed to two refrigerant path inlets 62 at the branching section 64. Therefore, the refrigerant R can be supplied to multiple refrigerant paths 61 while keeping the resistance of the diversion pipe 56 low.

[0067] (6) Variant (6-1) In the embodiment described above, each branch 64 connects one diversion pipe 56 to two refrigerant path inlets 62. Alternatively, each branch 64 may connect one diversion pipe 56 to three or more refrigerant path inlets 62.

[0068] (6-2) The refrigeration cycle device 100 according to the above embodiment has one heat source unit 10 and one utilization unit 20. Alternatively, the refrigeration cycle device 100 may have one heat source unit 10 and multiple utilization units 20. Furthermore, the refrigeration cycle device 100 may have multiple heat source units 10.

[0069] <Second Embodiment> (1) Overall structure Figure 8 shows the configuration of the refrigeration cycle device 100A according to the second embodiment. The refrigeration cycle device 100A differs from the refrigeration cycle device 100 according to the first embodiment in that the heat source unit 10 does not have a bridge circuit 40, while the utilization unit 20 has a bridge circuit 80.

[0070] (2) Detailed configuration The refrigeration cycle device 100A has a heat exchanger 23 and a bridge circuit 80.

[0071] (2-1) Heat exchanger 23 and fan 24 Unlike the first embodiment, the utilization heat exchanger 23 and utilization fan 24 have the same configuration as the heat source heat exchanger 13 and heat source fan 14 in the first embodiment. The utilization heat exchanger 23 has a refrigerant inlet pipe 23a and a refrigerant outlet pipe 23b. The refrigerant R enters the utilization heat exchanger 23 through the refrigerant inlet pipe 23a and exits the utilization heat exchanger 23 through the refrigerant outlet pipe 23b. The utilization fan 24 promotes heat exchange between air and refrigerant R by generating an airflow AF that passes through the utilization heat exchanger 23.

[0072] (2-2) Bridge circuit 80 The bridge circuit 80 ensures that the direction of travel of the refrigerant R in the heat exchanger 23 is always the same. Due to the function of the bridge circuit 80, regardless of whether the direction of travel of the refrigerant R is indicated by arrow CO or arrow HO, the refrigerant R always enters the heat exchanger 23 at the refrigerant inlet pipe 23a and always exits the heat exchanger 23 at the refrigerant outlet pipe 23b.

[0073] The bridge circuit 80 has a first node A', a second node B', a third node C', and a fourth node D'. The first node A' is connected to the refrigerant outlet pipe 23b. The second node B' is connected to the compressor 11 via a four-way switching valve 12. The third node C' is connected to the refrigerant inlet pipe 23a. The fourth node D' is connected to the heat source expansion valve 15.

[0074] Furthermore, the bridge circuit 80 has a first channel A'B' extending from the first node A' to the second node B', a second channel B'C' extending from the second node B' to the third node C', a third channel D'C' extending from the fourth node D' to the third node C', and a fourth channel A'D' extending from the first node A' to the fourth node D'.

[0075] The bridge circuit 80 includes a first check valve 81, a second check valve 82, a third check valve 83, and a fourth check valve 84. These check valves maintain the same direction of flow of the refrigerant R in the installed flow path and prevent backflow of the refrigerant R. The first check valve 41 is located in the first flow path A'B' and allows the refrigerant R to flow only in the direction from the first node A' to the second node B'. The second check valve 42 is located in the second flow path B'C' and allows the refrigerant R to flow only in the direction from the second node B' to the third node C'. The third check valve 43 is located in the third flow path D'C' and allows the refrigerant R to flow only in the direction from the fourth node D' to the third node C'. The fourth check valve 44 is located in the fourth flow path A'D' and allows the refrigerant R to flow only in the direction from the first node A' to the fourth node D'.

[0076] (3) Detailed structure of the heat exchanger 23 The heat exchanger 23 used in this embodiment has the same configuration as the heat source heat exchanger 13 of the first embodiment shown in Figure 7.

[0077] The refrigerant path inlet 62 of the lowest path 61L is located at a height H1. The refrigerant path inlet 62 of the highest path 61H is located at a height H2. The height H0 of all of the outlets 54 is lower than the height H1 of the lowest path 61L.

[0078] The heat exchanger body 60 has a plurality of branch sections 64. Each branch section 64 is composed of branched piping having, for example, one inlet and two outlets. Each branch section 64 is located at one of the plurality of refrigerant path inlets 62. Each branch section 64 connects one flow distribution pipe 56 to two refrigerant path inlets 62.

[0079] (4) Features In the utilization heat exchanger 23, as with the heat source heat exchanger 13 of the first embodiment, the number of branch pipes 56 is less than the number of merging pipes 75, so each branch pipe 56 can be made wider. As a result, the resistance due to pressure loss experienced by the refrigerant R through the branch pipes 56 can be reduced.

[0080] (5) Variant Modifications of the first embodiment may also be applied to this embodiment.

[0081] <Third Embodiment> (1) Overall structure Figure 9 shows the configuration of the refrigeration cycle device 100B according to the third embodiment. The refrigeration cycle device 100B differs from the refrigeration cycle device 100 according to the first embodiment and the refrigeration cycle device 100A according to the second embodiment in that the heat source unit 10 and the utilization unit 20 each have a bridge circuit 40 and a bridge circuit 80. The configuration of the bridge circuit 40 and the bridge circuit 80 is the same as in the first or second embodiment.

[0082] (2) Characteristics In both the heat source heat exchanger 13 and the utilization heat exchanger 23, the resistance caused by pressure loss experienced by the refrigerant R from the distribution pipe 56 can be reduced.

[0083] (3) Variation The variations of the first embodiment or the second embodiment may be applied to this embodiment.

[0084] <Conclusion> As described above, the embodiments of the present disclosure have been explained. It will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure described in the claims.

Description of Reference Numerals

[0085] 10: Heat source unit 12: Four-way switching valve 13: Heat source heat exchanger 13a: Refrigerant inlet pipe 13b: Refrigerant outlet pipe 14: Heat source fan 20: Utilization unit 23: Utilization heat exchanger 23a: Refrigerant inlet pipe 23b: Refrigerant outlet pipe 24: Utilization fan 30: Connection pipe group 40, 80: Bridge circuit (refrigerant rectifying section) 50: Shunt 51: Shunt body 53: Intake port 54: Discharge port 56: Shunt pipe 60: Heat exchanger body 61: Refrigerant path 61H: Highest path 61L: Lowest path 62: Refrigerant path inlet 63: Refrigerant path outlet 64: Branch portion 65: Heat transfer pipe 70: Confluence 75: Confluence pipe 76: Confluence body 100, 100A, 100B: Refrigeration cycle device H0: Height of the discharge port H1: Height of the lowest path H2: Height of the highest pass R: Refrigerant [Prior art documents] [Patent Documents]

[0086] [Patent Document 1] Japanese Patent Publication No. 2009-222362

Claims

1. A four-way switching valve (12) for switching between the first operation and the second operation, A first heat exchanger (13) having a refrigerant inlet pipe (13a) and a refrigerant outlet pipe (13b), which functions as a condenser in the first operation and as an evaporator in the second operation, A second heat exchanger (23) that functions as an evaporator in the first operation and as a condenser in the second operation, In either the first operation or the second operation, a refrigerant straightening section (40) flows the refrigerant so that it flows into the first heat exchanger at the refrigerant inlet pipe and out of the first heat exchanger at the refrigerant outlet pipe, A refrigeration cycle device (100) comprising, The first heat exchanger is, A heat exchanger body (60) having a plurality of refrigerant paths (61) through which the refrigerant passes, A flow divider (50) for distributing the refrigerant to the plurality of refrigerant paths, A merger (70) that brings together the refrigerant from the plurality of refrigerant paths, It further possesses, The aforementioned diversion device is A flow divider body (51) having one intake port (53) and multiple outlet ports (54) connected to the refrigerant inlet pipe, Multiple distribution pipes (56) connecting the multiple outlets and the multiple refrigerant paths, It has, The aforementioned merging device is, Multiple junction pipes (75) connected to the aforementioned multiple refrigerant paths, All of the aforementioned multiple merging pipes and the merging unit body (76) connected to the refrigerant outlet pipe, It has, The number of the aforementioned multiple branch pipes (56) is less than the number of the aforementioned multiple merging pipes (75). Refrigeration cycle device (100).

2. The aforementioned plurality of refrigerant paths are The lowest level path (61L) is located at the lowest height (H1), and The highest-level pass (61H) is located at the highest height (H2). Includes, The heights (H0) of the multiple outlets are all lower than the height (H1) of the lowest path. The refrigeration cycle apparatus according to claim 1.

3. The number of the aforementioned multiple branch pipes (56) is less than half the number of the aforementioned multiple merging pipes (75). The refrigeration cycle apparatus according to claim 2.

4. Each of the aforementioned plurality of refrigerant paths has a heat transfer tube (65), The inner diameter of each of the aforementioned multiple diversion pipes is 80% or more and 120% or less of the inner diameter of the heat transfer tube. A refrigeration cycle apparatus according to any one of claims 1 to 3.

5. The heat exchanger body is, A plurality of refrigerant path inlets (62) are points where the refrigerant flows into the plurality of refrigerant paths, Multiple branch sections (64) provided at any of the above-mentioned multiple refrigerant path inlets, It has, Each of the multiple branch sections (64) connects one of the multiple diversion pipes (56) to at least two of the multiple refrigerant path inlets (62). A refrigeration cycle apparatus according to any one of claims 1 to 3.

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