Refrigeration cycle device

Abstract

A refrigeration cycle device (100) is provided with 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 flow divider (50), and a flow combiner (70). The bridge circuit (40) causes a refrigerant (R) to flow so as to always enter the heat source heat exchanger (13) through the refrigerant inlet pipe (13a) and to exit the heat source heat exchanger (13) through the refrigerant outlet pipe (13b). The plurality of refrigerant paths (61) are connected to a plurality of flow dividing pipes (56) of the flow divider (50) and to a plurality of flow combining pipes (75) of the flow combiner (70). The number of flow dividing pipes (56) is smaller than the number of flow combining pipes (75).

Description

Refrigeration cycle device

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

[0002] The refrigeration cycle device 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 device 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 device executes either cold heat utilization operation or warm heat utilization operation, thereby realizing counterflow in the heat source heat exchanger.

[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, gas refrigerant suffers a large pressure loss from the piping. Therefore, the plurality of diverter pipes for guiding the high-pressure gas refrigerant after diversion need to be designed thick in order to reduce the pressure loss.

[0005] However, when the heat exchanger functions as an evaporator, the low-pressure gas-liquid two-phase refrigerant containing a heavy liquid component cannot obtain sufficient speed when passing through the plurality of thick diverter pipes. For this reason, the low-pressure gas-liquid two-phase refrigerant may not be able to reach from the diverter body disposed at a low position to the refrigerant path at a high position.

[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, second, or 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 diversion 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 diversion piping low.

[0016] This is a schematic diagram showing the configuration of the refrigeration cycle device 100 according to the first embodiment. This is a schematic diagram showing the configuration of the heat source heat exchanger 13. This is a schematic diagram showing the configuration of the heat exchanger body 60. This is a schematic diagram showing the counterflow of refrigerant R and airflow AF in the heat source heat exchanger 13. This is a graph showing the temperature change of refrigerant R and airflow AF in cooling operation. This is a graph showing the temperature change of refrigerant R and airflow AF in heating operation. This is a schematic diagram showing the detailed structure of the heat source heat exchanger 13. This is a schematic diagram showing the configuration of the refrigeration cycle device 100A according to the second embodiment. This is a schematic diagram showing the configuration of the refrigeration cycle device 100B according to the third embodiment.

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

[0018] (2) Detailed composition (2-1) Refrigerant R Refrigerant R is a non-azeotropic mixed refrigerant. A non-azeotropic mixed refrigerant is a refrigerant made by mixing multiple refrigerant components with different boiling points. Refrigerant R is, for example, R454C. R454C is a mixture of R32 and R1234yf.

[0019] Non-azeotropic refrigerant mixtures exhibit significant temperature glide. Temperature glide refers to the range of temperature changes observed during the evaporation or condensation of a refrigerant R. During the evaporation of a non-azeotropic refrigerant mixture, the low-boiling point components evaporate first, followed by the high-boiling point components. During the condensation of a non-azeotropic refrigerant mixture, the high-boiling point components condense first, followed by the low-boiling point components. The presence of multiple boiling points in this way causes significant temperature glide.

[0020] (2-2) Heat source unit 10 The heat source unit 10 obtains cold or hot energy from the air, which is the 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 the 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 the 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) Structural diagram 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 has a flow divider 50, a heat exchanger body 60, and a flow merger 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 intake port 53 and a plurality of outlet ports 54. The refrigerant inlet pipe 13a is connected to the intake port 53. The plurality of flow divider pipes 56 are connected to their respective outlet ports 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 a plurality of refrigerant paths 61 through which the refrigerant R flows. The plurality of 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 plurality of refrigerant path inlets 62 are connected to the flow distribution pipe 56 via a plurality of branching sections 64. The plurality of branching sections 64 will be described later.

[0029] The merging unit 70 has a plurality of 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 plurality of 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 device 50 is 80% or more and 120% or less of the inner diameter of the heat transfer tubes 65.

[0031] (2-2-3-3) Counterflow diagram 4 schematically shows 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 arranged 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 arranged 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 through the heat transfer tubes 65 in the first row L1 first, 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 moves 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 for ensuring 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 a bridge circuit 40, the direction of the refrigerant R flowing through the heat exchanger is reversed each time the operation is switched between cooling operation and heating operation. 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 operation 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 channel AB extending from the first node A to the second node B, a second channel BC extending from the second node B to the third node C, a third channel DC extending from the fourth node D to the third node C, and a fourth channel 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 provided 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 provided 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 provided 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 provided 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 that can adjust the degree of opening. When the degree of opening of the heat source expansion valve 15 is set to a small size, 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 stores only the liquid component contained in the refrigerant R inside, allowing only the gaseous component to pass through. The accumulator 16 is connected to the suction pipe 11a of the compressor 11, and prevents 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 gas shut-off valve 18 are for manually shutting off the movement of the refrigerant R. The liquid shut-off valve 17 and gas shut-off valve 18 are opened and closed manually by the installer of the refrigeration cycle device 100.

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

[0042] (2-3-1) Utilization heat exchanger 23 The utilization heat exchanger 23 provides cold or warm heat to the user by performing heat exchange of the refrigerant R such as the air in the environment where the user is located or the water used by the user. When performing cold heat utilization operation, the utilization heat exchanger 23 functions as an evaporator of the refrigerant R and provides cold heat to the user. When performing warm heat utilization operation, the utilization heat exchanger 23 functions as a condenser of the refrigerant R and provides warm heat to the user. As described above, the term "condenser" here includes the use as a radiator without phase transition of the refrigerant R, and the term "evaporator" may include the use as a heat absorber without phase transition of the refrigerant R.

[0043] (2-3-2) Utilization fan 24 The utilization fan 24 is provided when the user utilizes cold or warm heat through air. The utilization fan 24 promotes heat exchange between the air and the refrigerant R by generating an air flow passing through the utilization heat exchanger 23.

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

[0045] (3) Overall operation (3-1) Cold heat utilization operation When performing cold heat utilization operation, the four-way switching valve 12 realizes the connection shown by the solid line in FIG. 1 and makes the refrigerant R proceed 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 through the gas connecting pipe 32, the gas shut-off valve 18, 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.

[0047] (3-2) Thermal Energy Utilization Operation When performing thermal energy utilization operation, the four-way switching valve 12 is connected as shown by the dashed line in Figure 1, and the refrigerant R is advanced in the direction indicated by the arrow HO.

[0048] The compressor 11 sucks in the refrigerant R in a low-pressure gas state from the suction pipe 11a and discharges the refrigerant R in a high-pressure gas state from the discharge pipe 11b. The refrigerant R in a high-pressure gas state passes through the four-way switching valve 12, the gas shut-off valve 18, and the gas connection pipe 32 in sequence and reaches the utilization heat exchanger 23. The utilization heat exchanger 23 condenses the refrigerant R in a high-pressure gas state, provides the user with the thermal energy carried by the refrigerant R, and generates the refrigerant R in a high-pressure liquid state. Thereafter, the refrigerant R passes through the liquid connection pipe 31 and the liquid shut-off valve 17 and reaches the heat source expansion valve 15. Thereafter, the refrigerant R in a high-pressure liquid state is depressurized at the heat source expansion valve 15 and becomes the refrigerant R in a gas-liquid two-phase state. Thereafter, the refrigerant R passes through the fourth node D, the third check valve 43, and the third node C in sequence. Thereafter, the refrigerant R enters the heat source heat exchanger 13 at the refrigerant inlet pipe 13a. The heat source heat exchanger 13 generates the refrigerant R in a low-pressure gas state by evaporating the refrigerant R using the thermal energy of the air. The refrigerant R in a low-pressure gas state exits the heat source heat exchanger 13 from the refrigerant outlet pipe 13b and then reaches the first node A. Thereafter, the refrigerant R passes through the first check valve 41 and reaches the second node B. Thereafter, after the refrigerant R passes through the four-way switching valve 12 and the accumulator 16 in sequence, it is sucked into the compressor 11 at the suction pipe 11a.

[0049] (3-3) Effect of countercurrent in the heat source heat exchanger 13 FIGS. 5 and 6 are examples of temperature changes of the refrigerant R and the air flow AF in the heat source heat exchanger 13. The horizontal axis indicates the position y in the y direction. y1 is the position of the fin rear end 672, and y2 is the position of the fin front end 671. The vertical axis indicates the temperature T of the refrigerant R and the air flow AF. The numerical values of the temperature T shown are merely examples.

[0050] FIG. 5 shows the temperature change in the cold heat utilization operation. This figure assumes that the heat source heat exchanger 13 realizes the countercurrent of the refrigerant R and the air flow AF. The air flow AF proceeds from the position y1 of the fin rear end 672 to the position y2 of the fin front end 671. On the other hand, the refrigerant R proceeds from the position y2 of the fin front end 671 to the position y1 of the fin rear end 672.

[0051] The heat source heat exchanger 13 functions as a condenser. Inside 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. In the heat source heat exchanger 13, the refrigerant R receives heat from the airflow AF, so as the airflow AF moves from position y1 to position y2, the temperature of the airflow AF decreases.

[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, there is no bridge circuit 40 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 rate of refrigerant R The circulation rate of refrigerant R in the refrigeration cycle device 100 varies depending on the operating conditions, increasing or decreasing within a range from the minimum value to the maximum value. In the refrigeration cycle device 100, the circulation rate of refrigerant R may be significantly low. In both cold energy utilization operation and heat energy utilization operation, the minimum value of the 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 height H0 of all of the multiple outlets 54 is 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 provided at one of the plurality of refrigerant path inlets 62. Each branch section 64 connects one diversion pipe 56 to two refrigerant path inlets 62.

[0063] (5) Features (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 from the branch pipes 56 can be reduced.

[0064] (5-2) The height of the outlet 54 of the flow divider body 51 of the flow divider 50 is lower than the height H1 of the lowest pass 61L. Therefore, the flow divider piping 56 extending from the flow divider body 51 to each refrigerant pass inlet 62 is long. Even when the flow divider piping 56 is long in this way, the refrigerant R flowing through the wide flow divider piping 56 does not encounter much resistance. Therefore, the refrigerant R can rise through the flow divider piping 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 a large number of refrigerant paths 61 while keeping the resistance of the diversion pipe 56 low.

[0067] (6) Modified Examples (6-1) In the above-described embodiment, 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 Configuration Diagram 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) Utilizing heat exchanger 23 and utilizing fan 24 Unlike the first embodiment, the utilizing heat exchanger 23 and utilizing fan 24 have the same configuration as the heat source heat exchanger 13 and heat source fan 14 in the first embodiment. The utilizing heat exchanger 23 has a refrigerant inlet pipe 23a and a refrigerant outlet pipe 23b. The refrigerant R enters the utilizing heat exchanger 23 through the refrigerant inlet pipe 23a and exits the utilizing heat exchanger 23 through the refrigerant outlet pipe 23b. The utilizing fan 24 promotes heat exchange between air and refrigerant R by generating an airflow AF that passes through the utilizing 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 flow path A'B' extending from the first node A' to the second node B', a second flow path B'C' extending from the second node B' to the third node C', a third flow path D'C' extending from the fourth node D' to the third node C', and a fourth flow path 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 provided 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 provided 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 provided 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 provided 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 utilization heat exchanger 23 The utilization heat exchanger 23 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 multiple 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 provided at one of the plurality of refrigerant path inlets 62. Each branch section 64 connects one diversion pipe 56 to two refrigerant path inlets 62.

[0079] (4) Features In the 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 from the branch pipes 56 can be reduced.

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

[0081] <Third Embodiment> (1) Overall Configuration Diagram 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) Features: In both the heat source heat exchanger 13 and the utilization heat exchanger 23, the resistance due to pressure loss received by the refrigerant R from the distribution pipe 56 can be reduced.

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

[0084] <Conclusion> The embodiments of this disclosure have been described above, but it should be understood that various modifications to the form and details are possible without departing from the purpose and scope of this disclosure as described in the claims.

[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: Connecting piping group 40, 80: Bridge circuit (refrigerant rectification section) 50: Diverter 51: Diverter body 53: Inlet 54: Outlet 56: Diverter piping 60: Heat exchanger body 61: Refrigerant path 61H: Highest level path 61L: Lowest level path 62: Refrigerant path inlet 63: Refrigerant path outlet 64: Branch section 65: Heat transfer tube 70: Merger 75: Merger piping 76 : Combiner body 100, 100A, 100B: Refrigeration cycle device H0: Height of outlet H1: Height of lowest pass H2: Height of highest pass R: Refrigerant

[0086] Japanese Patent Publication No. 2009-222362

Claims

1. A refrigeration cycle device (100) comprising: a four-way switching valve (12) for switching between a first operation and a 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) which functions as an evaporator in the first operation and as a condenser in the second operation; and a refrigerant straightening section (40) that 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 either the first or second operation, wherein the first heat exchanger further comprises: a heat exchanger body (60) having a plurality of refrigerant paths (61) through which the refrigerant passes; a flow divider (50) for dividing the refrigerant into the plurality of refrigerant paths; and a merger (70) for converging the refrigerant from the plurality of refrigerant paths, the flow divider is A refrigeration cycle device (100) comprising: a splitter body (51) having one intake port (53) and a plurality of outlet ports (54) connected to the refrigerant inlet pipe; and a plurality of splitter pipes (56) connecting the plurality of outlet ports to the plurality of refrigerant paths, respectively; and a merging device comprising a plurality of merging pipes (75) connected to the plurality of refrigerant paths; and a merging device body (76) connected to all of the plurality of merging pipes and the refrigerant outlet pipe, wherein the number of the plurality of splitter pipes (56) is less than the number of the plurality of merging pipes (75).

2. The refrigeration cycle apparatus according to claim 1, wherein the plurality of refrigerant paths include a lowest-level path (61L) located at the lowest height (H1) and a highest-level path (61H) located at the highest height (H2), and the height of each of the plurality of outlets (H0) is lower than the height of the lowest-level path (H1).

3. The refrigeration cycle apparatus according to claim 1 or claim 2, wherein the number of the plurality of branch pipes (56) is less than or equal to half the number of the plurality of merging pipes (75).

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

5. The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the heat exchanger body has a plurality of refrigerant path inlets (62) which are points into which the refrigerant flows into the plurality of refrigerant paths, and a plurality of branching sections (64) provided at any one of the plurality of refrigerant path inlets, and each of the plurality of branching sections (64) connects one of the plurality of diversion pipes (56) to at least two of the plurality of refrigerant path inlets (62).

Images