Heat source unit

Abstract

To provide a split-type air conditioning system reduced in a risk that the composition ratio of non-azeotropic refrigerant mixture is changed when installed.SOLUTION: In an air conditioning system 1, an outdoor unit 20 and an indoor unit 30 are connected via a liquid refrigerant pipe 5 and a gas refrigerant pipe 6 in an installation site to form a refrigerant circuit 10. Refrigerant to be filled in the refrigerant circuit 10 is a non-azeotropic refrigerant mixture of which temperature glide becomes 1°C or higher during vaporization and condensation. The length of each of the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 is determined according to the installation positions from the outdoor unit 20 and the indoor unit 30. For the lengths of the liquid refrigerant pipe 5 and the gas refrigerant pipe 6, a first length L1 not required for additional filling of the refrigerant into the refrigerant circuit 10 is previously set. In the outdoor unit 20, the refrigerant is previously filled, of which amount accords to the required refrigerant amount in the refrigerant circuit 10 in the case that the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 each have the first length L1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a heat source unit that uses a non-azeotropic refrigerant mixture. [Background technology]

[0002] In a heat pump device using a non-azeotropic refrigerant mixture, there is a risk that the composition ratio will change when the refrigerant is filled on-site. To reduce such a risk, for example, in a heat pump hot water supply device disclosed in Patent Document 1 (International Publication WO2013 / 111180), a refrigerant is filled into a specific refrigeration cycle (second refrigeration cycle) before shipping from the factory. Summary of the Invention [Problem to be solved by the invention]

[0003] However, the above-mentioned refrigeration cycle is possible to fill with refrigerant before shipping because a closed refrigerant circuit is already formed at the factory, and it cannot be applied to split-type air conditioners in which the refrigerant circuit is formed by connecting the utilization unit and the heat source unit with piping at the installation site.

[0004] Therefore, there is an issue to provide a split-type air conditioner that reduces the risk of the composition ratio of the non-azeotropic refrigerant mixture changing during installation. [Means for solving the problem]

[0005] A heat source unit according to a first aspect is a heat source unit configured to form a refrigerant circuit by being connected to a utilization unit via piping at an installation location. The refrigerant filled into the heat source unit is a non-azeotropic refrigerant having a temperature glide of 1°C or more during evaporation and condensation. The heat source unit is pre-filled with an amount of refrigerant required for the refrigerant circuit when the length of the piping is a first length that makes it unnecessary to additionally fill the refrigerant into the refrigerant circuit.

[0006] It is not easy to charge a non-azeotropic refrigerant mixture on-site while maintaining the composition ratio. Therefore, by charging the refrigerant into the heat source unit in advance and eliminating the need for on-site charging, the composition ratio of the non-azeotropic refrigerant mixture can be maintained.

[0007] A heat source unit according to a second aspect is the heat source unit according to the first aspect, and is configured to form a refrigerant circuit by being connected to one utilization unit.

[0008] A heat source unit according to a third aspect is the heat source unit according to the first aspect, which is configured such that a refrigerant circuit is formed by connecting a plurality of utilization units in parallel.

[0009] A heat source unit according to a fourth aspect is the heat source unit according to any one of the first aspect to the third aspect, in which the temperature glide during evaporation and condensation of the refrigerant is 5° C. or more.

[0010] In the case of a non-azeotropic refrigerant with a temperature glide of 5° C. or more, it is difficult to charge the refrigerant on-site while maintaining the composition ratio. Therefore, in this heat source unit, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant is maintained by charging the refrigerant in advance into the heat source unit.

[0011] The heat source unit of the fifth aspect is a heat source unit of any one of the first aspect to the fourth aspect, and is configured to be connected to a pipe of 2.5 minutes or more (outer diameter 7.93 mm) through which liquid refrigerant or a gas-liquid mixed refrigerant flows.

[0012] When using a non-azeotropic refrigerant with a large pressure loss, the diameter of the pipe through which the liquid refrigerant or gas-liquid mixed refrigerant flows must be increased, and the amount of refrigerant charged increases. The greater the amount of charge, the greater the risk that the refrigerant composition ratio will change during on-site charging. Therefore, in this heat source unit, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant is maintained, by charging the heat source unit in advance with the refrigerant.

[0013] A heat source unit according to a sixth aspect is the heat source unit according to the fifth aspect, wherein the pipe through which the liquid refrigerant or the gas-liquid mixed refrigerant flows is a 2.5-section pipe (outer diameter 7.93 mm).

[0014] If the actual pipe length exceeds the first length, additional refrigerant charging is required, increasing the risk of a change in the refrigerant composition ratio. In order to reduce the risk of a change in the composition ratio in such a situation, a 2.5-minute pipe is appropriate for the pipe through which liquid refrigerant or gas-liquid mixed refrigerant flows, from the standpoints of both "suppressing pressure loss" and "suppressing the amount of additional refrigerant charged."

[0015] A heat source unit of a seventh aspect is a heat source unit of any one of the first aspect to the sixth aspect, wherein the amount of refrigerant pre-filled in the heat source unit is 2 to 3 times the amount of R32 refrigerant required in the entire refrigerant circuit when R32 refrigerant is filled into a refrigerant circuit whose piping is set to a first length.

[0016] Some non-azeotropic refrigerants require two to three times the amount of R32 refrigerant, which has zero temperature glide, and there is a high risk that the composition ratio of such refrigerants will change when they are filled on-site. Therefore, in this heat source unit, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant is maintained by filling the heat source unit with the refrigerant in advance.

[0017] A heat source unit according to an eighth aspect is the heat source unit according to any one of the first aspect to the seventh aspect, and has a first length of 30 m.

[0018] A heat source unit of a ninth aspect is the heat source unit of any one of the first aspect to the eighth aspect, and includes a first shut-off valve, a second shut-off valve, and a heat source circuit. The heat source circuit is a refrigerant flow path from the first shut-off valve to the second shut-off valve, and is configured to form a part of the refrigerant circuit. The heat source circuit includes a compressor, a heat exchanger, and a pressure reducer. The compressor, the heat exchanger, and the pressure reducer are connected in sequence. The heat source circuit further includes a high-pressure receiver connected between the heat exchanger and the pressure reducer.

[0019] In this heat source unit, the amount of refrigerant that can be pre-charged can include an amount of refrigerant equivalent to the internal volume of the high-pressure receiver.

[0020] A heat source unit according to a tenth aspect is the heat source unit according to the ninth aspect, wherein the volume ratio of the high-pressure receiver to the heat exchanger is within a range of 0.04 to 0.6. [Brief description of the drawings]

[0021] [Figure 1] 1 is a circuit diagram of a refrigerant circuit of an air-conditioning apparatus according to a first embodiment of the present disclosure. [Diagram 2] 4 is a table showing the composition ratio and temperature glide of the non-azeotropic refrigerant mixture used in the present embodiment. [Diagram 3] FIG. 6 is a circuit diagram of a refrigerant circuit of an air conditioner according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] First Embodiment (1) Configuration of Air Conditioner 1 1 is a circuit diagram of a refrigerant circuit 10 of an air conditioner 1 according to a first embodiment of the present disclosure. In the air conditioner 1, an indoor unit 30, which is one utilization unit, is connected to an outdoor unit 20, which is a heat source unit, via a liquid refrigerant pipe 5 and a gas refrigerant pipe 6.

[0023] The refrigerant filled into the refrigerant circuit 10 is a non-azeotropic refrigerant mixture that has a temperature glide of 1° C. or more during evaporation and condensation. Usually, the refrigerant is filled after the outdoor unit 20 and the indoor unit 30 are connected via the liquid refrigerant piping 5 and the gas refrigerant piping 6 at the installation location of the air conditioner 1.

[0024] However, in this embodiment, before the liquid refrigerant piping 5 and the gas refrigerant piping 6 are connected, the outdoor unit 20 is pre-filled with the amount of refrigerant required for the entire refrigerant circuit 10 when the liquid refrigerant piping 5 and the gas refrigerant piping 6 are set to the predetermined first length L1, regardless of the actual lengths of the liquid refrigerant piping 5 and the gas refrigerant piping 6.

[0025] (1-1) Outdoor unit 20 The outdoor unit 20 includes a compressor 11, a four-way switching valve 13, an outdoor heat exchanger 15, a bridge circuit section 17, a liquid-gas heat exchanger 19, a high-pressure receiver 21, an expansion valve 23, a liquid-side shut-off valve 25, a gas-side shut-off valve 26, and an accumulator 27.

[0026] The compressor 11, four-way switching valve 13, outdoor heat exchanger 15, bridge circuit section 17, liquid-gas heat exchanger 19, high-pressure receiver 21, expansion valve 23, and accumulator 27 are provided in the refrigerant flow path from the liquid side shut-off valve 25 to the gas side shut-off valve 26, and constitute a heat source circuit 20a, which is part of the refrigerant circuit 10.

[0027] Further, in order to promote heat exchange between the air and the outdoor heat exchanger 15, an outdoor fan 29 that generates an air flow is disposed in the outdoor unit 20.

[0028] (1-1-1) Compressor 11 The compressor 11 has a suction port 11a and a discharge port 11b. The refrigerant flows into the compressor 11 through the suction port 11a, is compressed to a high temperature and high pressure, and flows out from the discharge port 11b.

[0029] (1-1-2) Four-way switching valve 13 The four-way switching valve 13 has a first port P1, a second port P2, a third port P3, and a fourth port P4. The first port P1 is connected to the discharge port 11b of the compressor 11. The second port P2 is connected to the outdoor heat exchanger 15. The third port P3 is connected to the suction port 11a of the compressor 11 via the liquid-gas heat exchanger 19 and the accumulator 27. The fourth port P4 is connected to the gas-side shutoff valve 26.

[0030] (1-1-3) Outdoor heat exchanger 15 The outdoor heat exchanger 15 is an air heat exchanger. The outdoor heat exchanger 15 exchanges heat between the refrigerant flowing inside and the outside air sent from the outdoor fan 29. In this embodiment, a fin-and-tube heat exchanger is used as the outdoor heat exchanger 15.

[0031] (1-1-4) Bridge circuit section 17 The bridge circuit section 17 has four check valves 17a, 17b, 17c, and 17d connected in a bridge configuration. A first connection point S1 between the check valves 17a and 17b is connected to the outdoor heat exchanger 15. A second connection point S2 between the check valves 17a and 17c is connected to the expansion valve 23. A third connection point S3 between the check valves 17c and 17d is connected to the liquid-side stop valve 25. A fourth connection point S4 between the check valves 17b and 17d is connected to the liquid pipe 19a of the liquid-gas heat exchanger 19.

[0032] (1-1-5) Liquid-gas heat exchanger 19 The liquid-gas heat exchanger 19 exchanges heat between a high-pressure refrigerant flowing through a liquid pipe 19a and a low-pressure refrigerant flowing through a gas pipe 19b. The liquid-gas heat exchanger 19 is a double-pipe heat exchanger.

[0033] (1-1-6) High pressure receiver 21 The high-pressure receiver 21 temporarily stores the refrigerant supercooled in the liquid-gas heat exchanger 19.

[0034] (1-1-7) Expansion valve 23 The expansion valve 23 is disposed between the outlet of the high-pressure receiver 21 and the second connection point S2 of the bridge circuit unit 17. The expansion valve 23 reduces the pressure of the refrigerant flowing from the high-pressure receiver 21 to the second connection point S2 of the bridge circuit unit 17 to a predetermined low pressure.

[0035] (1-1-8) Liquid side shutoff valve 25 The liquid-side shut-off valve 25 is connected between the third connection point S3 of the bridge circuit portion 17 and the indoor heat exchanger 35. The liquid-side shut-off valve 25 and the indoor heat exchanger 35 are connected by a liquid refrigerant piping 5.

[0036] (1-1-9) Gas side shutoff valve 26 The gas-side shut-off valve 26 is connected in series with the four-way switching valve 13 between the four-way switching valve 13 and the indoor heat exchanger 35. The gas-side shut-off valve 26 and the indoor heat exchanger 35 are connected by the gas refrigerant piping 6.

[0037] (1-1-10) Accumulator 27 The accumulator 27 is connected between the four-way switching valve 13 and the suction port 11a of the compressor 11. The accumulator 24 collects the liquid refrigerant that was not gasified in the evaporator and prevents the liquid refrigerant from flowing into the suction port 11a of the compressor 11.

[0038] (1-1-11) Outdoor fan 29 The outdoor fan 29 generates an air flow to promote heat exchange between the air and the refrigerant flowing inside the outdoor heat exchanger 15. The outdoor fan 29 is a propeller fan.

[0039] (1-2) Indoor unit 30 An indoor heat exchanger 35 is disposed in the indoor unit 30. Also, in order to promote heat exchange between the air and the indoor heat exchanger 35, an indoor fan 37 that generates an air flow is disposed in the indoor unit 30.

[0040] (1-2-1) Indoor heat exchanger 35 The indoor heat exchanger 35 is an air heat exchanger. The indoor heat exchanger 35 exchanges heat between the refrigerant flowing inside and the indoor air sent from the indoor fan 37. In this embodiment, a fin-and-tube heat exchanger is used as the indoor heat exchanger 35.

[0041] One end of the indoor heat exchanger 35 is connected to the liquid side shutoff valve 25 via a liquid refrigerant pipe 5, and the other end is connected to the gas side shutoff valve 26 via a gas refrigerant pipe 6.

[0042] (1-2-2) Indoor fan 37 The indoor fan 37 generates an air flow to promote heat exchange between the indoor air and the refrigerant flowing inside the indoor heat exchanger 35. The indoor fan 37 is a sirocco fan.

[0043] (1-3) Liquid refrigerant pipe 5 and gas refrigerant pipe 6 The liquid refrigerant piping 5 and the gas refrigerant piping 6 connect the outdoor unit 20 and the indoor unit 30 to form a refrigerant circuit 10. The lengths of the liquid refrigerant piping 5 and the gas refrigerant piping 6 are determined according to the installation positions of the outdoor unit 20 and the indoor unit 30.

[0044] The liquid refrigerant pipe 5 connects between the liquid side shutoff valve 25 of the outdoor unit 20 and a refrigerant inlet of the indoor heat exchanger 35 of the indoor unit 30 during cooling operation (a refrigerant outlet during heating operation).

[0045] The gas refrigerant pipe 6 connects the gas side shutoff valve 26 of the outdoor unit 20 and a refrigerant outlet of the indoor heat exchanger 35 of the indoor unit 30 during cooling operation (a refrigerant inlet during heating operation).

[0046] When using a non-azeotropic refrigerant mixture with a large pressure loss, the diameter of the liquid refrigerant pipe 5 must be large, preferably 2.5 mm or more (outer diameter 7.93 mm). However, the amount of refrigerant charged increases, and the greater the charged amount, the greater the risk of the refrigerant composition ratio changing during on-site charging. Therefore, in this air conditioning device 1, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant mixture is maintained, by charging the outdoor unit 20 with the refrigerant in advance.

[0047] However, if the actual piping lengths of the liquid refrigerant piping 5 and the gas refrigerant piping 6 exceed the first length L1, additional charging of refrigerant becomes necessary, increasing the risk of a change in the refrigerant composition ratio. In order to reduce the risk of a change in the composition ratio in such a situation, a 2.5-section pipe is suitable for the liquid refrigerant piping 5 in this air conditioning device 1 from the standpoints of both "suppressing pressure loss" and "suppressing the amount of additional refrigerant charged."

[0048] (1-4) Control unit 40 The control unit 40 controls the operating frequency of the compressor 11, controls the switching of the four-way switching valve 13, and controls the opening degree of the expansion valve 23. The control unit 40 is composed of a microprocessor and a printed circuit board equipped with a memory.

[0049] (1-5) Refrigerant The refrigerant used in this embodiment is a non-azeotropic refrigerant mixture. A non-azeotropic refrigerant mixture is a mixture of two or more refrigerants with different boiling points. Since a refrigerant with a higher boiling point condenses before a refrigerant with a lower boiling point, the isotherm of the non-azeotropic refrigerant mixture slopes downward to the right from the saturated liquid line to the saturated vapor line. Therefore, a temperature glide occurs on the saturated liquid line and the saturated vapor line under the same pressure condition.

[0050] 2 is a table showing the composition ratios and temperature glides of the non-azeotropic refrigerant mixtures used in this embodiment. The physical property values ​​of R454B, R454C, and R474A are determined based on the composition ratios shown in FIG.

[0051] (2) Operation of the Air Conditioner 1 Here, the operation of the air conditioner 1 will be described using cooling operation and heating operation as examples.

[0052] (2-1) Cooling operation During cooling operation, the four-way switching valve 13 is held in the state shown by the solid line in Fig. 1. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 15 via the four-way switching valve 13, and is condensed by exchanging heat with the outdoor air.

[0053] The condensed refrigerant passes through the first connection point S1, the check valve 17b, and the fourth connection point S4 of the bridge circuit portion 17 and flows into the liquid pipe 19a of the liquid-gas heat exchanger 19. The refrigerant flowing through the liquid pipe 19a exchanges heat with the refrigerant flowing through the gas pipe 19b and is subcooled.

[0054] The refrigerant that has flowed through the liquid pipe 19a is temporarily stored in the high-pressure receiver 21. The refrigerant that has flowed out of the high-pressure receiver 21 is reduced in pressure to a predetermined low pressure in the expansion valve 23. The refrigerant reduced in pressure in the expansion valve 23 flows into the indoor heat exchanger 35 via the second connection point S2, the check valve 17c, and the third connection point S3 of the bridge circuit unit 17. The refrigerant exchanges heat with the indoor air in the indoor heat exchanger 35 and evaporates. The indoor air that has been cooled by the evaporation of the refrigerant is then blown into the room by the corresponding indoor fan 37, cooling the room.

[0055] The refrigerant evaporated in the indoor heat exchanger 35 flows into the gas pipe 19b of the liquid-gas heat exchanger 19 via the gas refrigerant pipe 6 and the four-way switching valve 13.

[0056] The refrigerant flowing through the gas pipe 19b exchanges heat with the refrigerant flowing through the liquid pipe 19a and becomes superheated vapor. The refrigerant flowing through the gas pipe 19b passes through the accumulator 27 and is sucked into the compressor 11.

[0057] (2-2) Heating operation During heating operation, the four-way switching valve 13 is held in the state shown by the dashed line in Fig. 1. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the indoor heat exchanger 35 via the four-way switching valve 13, and condenses by exchanging heat with the indoor air.

[0058] The indoor air heated by heat exchange with the refrigerant is blown out into the room by the indoor fan 37, heating the room.

[0059] The refrigerant condensed in the indoor heat exchanger 35 flows through the liquid refrigerant pipe 5 and reaches the bridge circuit unit 17. The refrigerant passes through the third connection point S3, the check valve 17d, and the fourth connection point S4 of the bridge circuit unit 17, and flows into the liquid pipe 19a of the liquid-gas heat exchanger 19. The refrigerant flowing through the liquid pipe 19a exchanges heat with the refrigerant flowing through the gas pipe 19b and is subcooled.

[0060] The refrigerant that has flowed through the liquid pipe 19a is temporarily stored in the high-pressure receiver 21. Then, the refrigerant that flows out of the high-pressure receiver 21 is reduced in pressure to a predetermined low pressure by the expansion valve 23. The reduced-pressure refrigerant passes through the second connection point S2 of the bridge circuit unit 17, the check valve 17a, and the first connection point S1, and flows into the outdoor heat exchanger 15. In the outdoor heat exchanger 15, the refrigerant exchanges heat with the outdoor air and evaporates.

[0061] The refrigerant evaporated in the outdoor heat exchanger 15 flows into the gas pipe 19b of the liquid-gas heat exchanger 19 through the four-way switching valve 13. The refrigerant flowing through the gas pipe 19b exchanges heat with the refrigerant flowing through the liquid pipe 19a and becomes superheated vapor. The refrigerant flowing through the gas pipe 19b passes through the accumulator 27 and is sucked into the compressor 11.

[0062] (3) Charging refrigerant into the outdoor unit 20 Usually, the refrigerant is filled at the installation location of the air conditioning apparatus 1 after the outdoor unit 20 and the indoor unit 30 are connected via the liquid refrigerant piping 5 and the gas refrigerant piping 6. The lengths of the liquid refrigerant piping 5 and the gas refrigerant piping 6 are determined according to the installation positions of the outdoor unit 20 and the indoor unit 30.

[0063] However, in the air conditioner 1 of the present embodiment, a non-azeotropic refrigerant mixture is used, and there is a high risk that the composition ratio will change when the refrigerant is charged after installation, so it is necessary to reduce this risk.

[0064] Therefore, the heat source circuit 20a of the outdoor unit 20 is pre-filled with an amount of refrigerant corresponding to the amount of refrigerant required in the refrigerant circuit 10 when the liquid refrigerant piping 5 and the gas refrigerant piping 6 have a predetermined first length L1. The first length L1 is a length that makes it unnecessary to additionally fill the refrigerant into the refrigerant circuit 10 formed by connecting the outdoor unit 20 and the indoor unit 30 via the liquid refrigerant piping 5 and the gas refrigerant piping 6. In this embodiment, the first length L1 is set to 30 m.

[0065] The refrigerant is filled into the outdoor heat exchanger 15, the liquid-gas heat exchanger 19, the high-pressure receiver 21, the accumulator 27, and the pipes connecting them, which are included in the heat source circuit 20a of the outdoor unit 20.

[0066] The amount of non-azeotropic refrigerant mixture pre-filled in the outdoor unit 20 is, for example, 2 to 3 times the amount of R32 refrigerant required for the entire refrigerant circuit 10 when R32 refrigerant is filled into the refrigerant circuit 10 in which the liquid refrigerant piping 5 and the gas refrigerant piping 6 are set to a first length.

[0067] In this embodiment, the diameter of the pipes in the outdoor unit 20 is made larger than the diameter of the pipes in the indoor unit 30 in order to increase the amount of refrigerant that can be pre-charged in the outdoor unit 20.

[0068] In order to ensure that the amount of refrigerant pre-filled in the outdoor unit 20 is sufficient for the amount of refrigerant required in the entire refrigerant circuit 10, the volume ratio of the outdoor heat exchanger 15 to the indoor heat exchanger 35 is set to 3 or more.

[0069] Furthermore, by setting the volume ratio of the high-pressure receiver 21 to the outdoor heat exchanger 15 within the range of 0.04 to 0.6, the amount of refrigerant pre-filled in the outdoor unit 20 can easily satisfy the amount of refrigerant required for the entire refrigerant circuit 10.

[0070] The installation work of the air conditioning apparatus 1 consists of a process of installing the outdoor unit 20 and the indoor unit 30 at the installation location, a process of connecting the outdoor unit 20 and the indoor unit 30 via liquid refrigerant piping 5 and gas refrigerant piping 6, and a process of sending the refrigerant filled in the outdoor unit 20 to the refrigerant circuit 10.

[0071] In the process in which the refrigerant filled in the outdoor unit 20 is sent to the refrigerant circuit 10, the liquid side shutoff valve 25 and the gas side shutoff valve 26 are opened, thereby filling the refrigerant circuit 10 with the refrigerant.

[0072] (4) Features (4-1) In the air conditioner 1, the outdoor unit 20 and the indoor unit 30 are connected via the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 at the installation location to form a refrigerant circuit 10. The refrigerant filled in the refrigerant circuit 10 is a non-azeotropic refrigerant mixture having a temperature glide of 1°C or more during evaporation and condensation. The lengths of the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 are determined according to the installation positions of the outdoor unit 20 and the indoor unit 30. The lengths of the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 are set in advance to a first length L1 (for example, L1 = 30m) at which additional filling of refrigerant into the refrigerant circuit 10 is unnecessary. The outdoor unit 20 is filled in advance with an amount of refrigerant corresponding to the amount of refrigerant required in the refrigerant circuit 10 when the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 have the first length L1.

[0073] It is not easy to charge a non-azeotropic refrigerant mixture on-site while maintaining the composition ratio. Therefore, in this air conditioner 1, the refrigerant is charged in advance into the outdoor unit 20, and the composition ratio of the non-azeotropic refrigerant mixture can be maintained by eliminating the need for on-site charging.

[0074] (4-2) In particular, when using R454C, which has a temperature glide of 5° C. or more when evaporating and condensing, it is difficult to charge the refrigerant on-site while maintaining the composition ratio. Therefore, in this air conditioner 1, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant mixture is maintained, by charging the outdoor unit 20 with the refrigerant in advance.

[0075] (4-3) The liquid refrigerant piping 5 is preferably a 2.5-section pipe (outer diameter 7.93 mm) or larger. When using a non-azeotropic refrigerant with a large pressure loss, the diameter of the liquid refrigerant piping 5 must be large, and the amount of refrigerant charged increases. The greater the charged amount, the greater the risk that the composition ratio of the refrigerant will change during on-site charging. Therefore, with this air conditioning device 1, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant is maintained, by charging the outdoor unit 20 with the refrigerant in advance.

[0076] However, if the actual piping length of the liquid refrigerant piping 5 and the gas refrigerant piping 6 exceeds the first length L1, additional charging of the refrigerant becomes necessary, further increasing the risk of the refrigerant composition ratio changing. In order to reduce the risk of the composition ratio changing in such a situation, a 2.5-section pipe is suitable for the liquid refrigerant piping 5 from the standpoints of both "suppressing pressure loss" and "suppressing the amount of additional refrigerant charged."

[0077] (4-4) The amount of the non-azeotropic mixed refrigerant pre-filled in the outdoor unit 20 is 2 to 3 times the amount of R32 refrigerant required in the entire refrigerant circuit 10 when a single R32 refrigerant is filled in the refrigerant circuit 10 in which the liquid refrigerant piping 5 and the gas refrigerant piping 6 are set to the first length L1. Some non-azeotropic refrigerants require a charging amount two to three times that of R32 refrigerant, which has a zero temperature glide, and there is a high risk that the composition ratio of such refrigerants will change when charging on-site. Therefore, in this air conditioner 1, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant is maintained by charging the outdoor unit 20 with the refrigerant in advance.

[0078] (4-5) Since the diameter of the pipes in the outdoor unit 20 is larger than the diameter of the pipes in the indoor unit 30, the amount of refrigerant that can be pre-charged in the outdoor unit 20 can be increased.

[0079] (4-6) The volume ratio of the outdoor heat exchanger 15 to the indoor heat exchanger 35 is equal to or greater than 3. This allows the amount of refrigerant pre-filled in the outdoor unit 20 to satisfy the amount of refrigerant required in the entire refrigerant circuit 10.

[0080] (4-7) The high-pressure receiver 21 is connected between the outdoor heat exchanger 15 and the expansion valve 23. The volume ratio of the high-pressure receiver 21 to the outdoor heat exchanger 15 is within a range of 0.04 to 0.6. The amount of refrigerant that can be pre-charged into the outdoor unit 20 can include an amount of refrigerant equivalent to the internal volume of the high-pressure receiver 21.

[0081] (4-8) The refrigerant circuit 10 is provided with a liquid-gas heat exchanger 19 that exchanges heat between a high-pressure liquid refrigerant and a low-pressure gas refrigerant. The liquid-gas heat exchanger 19 is a double-pipe heat exchanger. The amount of refrigerant that can be pre-filled into the outdoor unit 20 can include an amount of refrigerant equivalent to the internal volume of the liquid-gas heat exchanger 19.

[0082] (5)Other The worker performing the installation work of the air conditioner 1 judges whether the lengths of the liquid refrigerant piping 5 and the gas refrigerant piping 6 required for the installation work of the air conditioner 1 are equal to or shorter than the first length L1.

[0083] If the length of the liquid refrigerant piping 5 and the gas refrigerant piping 6 is less than or equal to the first length L1, the refrigerant additional charging process is not necessary because the refrigerant charged in the outdoor unit 20 is the same as or greater than the required refrigerant amount. Therefore, the installation work is completed after the outdoor unit 20 and the indoor unit 30 are connected via the liquid refrigerant piping 5 and the gas refrigerant piping 6 without the additional refrigerant charging process being performed.

[0084] In other words, the amount of refrigerant filled in the outdoor unit 20 is equal to or greater than the amount of refrigerant required in the refrigerant circuit 10 when the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 are equal to or shorter than the first length L1.

[0085] On the other hand, when the length of the liquid refrigerant pipe 5 and the gas refrigerant pipe 6 exceeds the first length L1, the refrigerant pre-filled in the outdoor unit 20 is insufficient for the required amount of refrigerant, so a process of additionally filling the refrigerant is required.

[0086] Therefore, a refrigerant additional charging process is performed, and an amount of refrigerant according to the lengths of the liquid refrigerant piping 5 and the gas refrigerant piping 6 is additionally charged into the refrigerant circuit 10. The refrigerant is additionally charged from the service port of the liquid side shut-off valve 25 or the gas side shut-off valve 26, for example.

[0087] <Second embodiment> (1) Configuration of the Air Conditioner 100 3 is a circuit diagram of a refrigerant circuit 110 of an air conditioner 100 according to a second embodiment of the present disclosure. The air conditioner 100 is a multi-room air conditioner in which multiple indoor units 30a, 30b, 30c, and 30d, which are utilization units, are connected in parallel to one outdoor unit 120, which is a heat source unit.

[0088] Here, the same names and symbols are given to configurations common to the first embodiment, and descriptions thereof are omitted, and only the portions different from the first embodiment will be described. (1-1) Outdoor unit 120 In the outdoor unit 120, the compressor 11, four-way switching valve 13, outdoor heat exchanger 15, bridge circuit section 17, liquid-gas heat exchanger 19, high-pressure receiver 21, expansion valve 23, and accumulator 27 are provided in the refrigerant flow path from liquid side shut-off valves 25a, 25b, 25c, and 25d to the gas side shut-off valve 26, and form a heat source circuit 120a, which is part of the refrigerant circuit 10.

[0089] The compressor 11, four-way switching valve 13, outdoor heat exchanger 15, bridge circuit section 17, liquid-gas heat exchanger 19, high-pressure receiver 21, expansion valve 23 and filling refrigerant are the same as those in the first embodiment, so description thereof will be omitted.

[0090] (1-1-1) Second expansion valves 24a, 24b, 24c, 24d The four second expansion valves 24a, 24b, 24c, and 24d are connected in parallel, and each of the second expansion valves 24a, 24b, 24c, and 24d is connected in series to a corresponding liquid-side shutoff valve 25a, 25b, 25c, and 25d.

[0091] (1-1-2) Liquid side shutoff valves 25a, 25b, 25c, 25d Each liquid side shut-off valve 25a, 25b, 25c, 25d is connected in series with the corresponding second expansion valve 24a, 24b, 24c, 24d between the corresponding second expansion valve 24a, 24b, 24c, 24d and the corresponding indoor heat exchanger 35a, 35b, 35c, 35d.

[0092] The liquid side shutoff valves 25a, 25b, 25c, and 25d are connected to the corresponding indoor heat exchangers 35a, 35b, 35c, and 35d by corresponding liquid refrigerant pipes 5a, 5b, 5c, and 5d, respectively.

[0093] (1-2) Indoor units 30a, 30b, 30c, 30d The indoor units 30a, 30b, 30c, and 30d are provided with indoor heat exchangers 35a, 35b, 35c, and 35d, respectively.

[0094] Further, indoor fans 37a, 37b, 37c, 37d that generate airflow are arranged in the indoor units 30a, 30b, 30c, 30d to promote heat exchange between the air and the indoor heat exchangers 35a, 35b, 35c, 35d.

[0095] (1-2-1) Indoor heat exchanger 35a, 35b, 35c, 35d The indoor heat exchangers 35a, 35b, 35c, and 35d are air heat exchangers. The indoor heat exchangers 35a, 35b, 35c, and 35d exchange heat between the refrigerant flowing therethrough and the indoor air sent from the corresponding indoor fans 37a, 37b, 37c, and 37d. In this embodiment, fin-and-tube heat exchangers are used as the indoor heat exchangers 35a, 35b, 35c, and 35d.

[0096] One end of the indoor heat exchanger 35a is connected to the liquid side shut-off valve 25a via the liquid refrigerant piping 5a, and the other end is connected to the gas side shut-off valve 26. Furthermore, one end of the indoor heat exchanger 35b is connected to the liquid side shut-off valve 25b via the liquid refrigerant piping 5b, and the other end is connected to the gas side shut-off valve 26 via the gas refrigerant piping 6. Furthermore, one end of the indoor heat exchanger 35c is connected to the liquid side shut-off valve 25c via the liquid refrigerant piping 5c, and the other end is connected to the gas side shut-off valve 26 via the gas refrigerant piping 6. Furthermore, one end of the indoor heat exchanger 35d is connected to the liquid side shut-off valve 25d via the liquid refrigerant piping 5d, and the other end is connected to the gas side shut-off valve 26 via the gas refrigerant piping 6.

[0097] (1-2-2) Indoor fans 37a, 37b, 37c, 37d The indoor fans 37a, 37b, 37c, and 37d generate airflows to promote heat exchange between the refrigerant and air flowing inside the corresponding indoor heat exchangers 35a, 35b, 35c, and 35d. The indoor fans 37a, 37b, 37c, and 37d are sirocco fans.

[0098] (1-3) Liquid refrigerant piping 5a, 5b, 5c, 5d The liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipes 6 connect the outdoor unit 120 and the indoor units 30a, 30b, 30c, and 30d to form a refrigerant circuit 110. The lengths of the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipes 6 are determined depending on the installation positions of the outdoor unit 120 and the indoor units 30a, 30b, 30c, and 30d.

[0099] The liquid refrigerant pipes 5a, 5b, 5c, and 5d connect the corresponding liquid side shut-off valves 25a, 25b, 25c, and 25d of the outdoor unit 120 to the refrigerant inlets of the corresponding indoor heat exchangers 35a, 35b, 35c, and 35d during cooling operation (refrigerant outlets during heating operation).

[0100] The gas refrigerant pipe 6 connects the gas side shutoff valve 26 of the outdoor unit 120 and the refrigerant outlets of the indoor heat exchangers 35a, 35b, 35d, and 35c during cooling operation (refrigerant inlets during heating operation).

[0101] When using a non-azeotropic refrigerant mixture with a large pressure loss, the pipe diameter of the liquid refrigerant pipes 5a, 5b, 5c, and 5d must be large, preferably 2.5 mm or more (outer diameter 7.93 mm). However, the amount of refrigerant charged increases, and the greater the charged amount, the greater the risk of the refrigerant composition ratio changing during on-site charging. Therefore, in this air conditioning device 100, there is a great advantage in pre-charging the outdoor unit 120 with the refrigerant, in that the composition ratio of the non-azeotropic refrigerant mixture is maintained.

[0102] However, if the actual piping lengths of the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipe 6 exceed the first length L1, additional charging of refrigerant becomes necessary, increasing the risk of a change in the composition ratio of the refrigerant. In order to reduce the risk of a change in the composition ratio in such a situation, in this air conditioning device 100, from the standpoints of both "suppressing pressure loss" and "suppressing the amount of additional refrigerant charged", the liquid refrigerant pipes 5a, 5b, 5c, and 5d are suitable as 2.5-branch pipes.

[0103] (1-4) Control unit 40 The control unit 40 controls the operating frequency of the compressor 11, the switching control of the four-way switching valve 13, the opening control of the expansion valve 23, and the opening control of the second expansion valves 24a, 24b, 24c, and 24d. The control unit 40 is composed of a printed circuit board equipped with a microprocessor and a memory.

[0104] (2) Operation of the Air Conditioner 100 Here, the operation of the air conditioner 100 will be described using cooling operation and heating operation as examples.

[0105] (2-1) Cooling operation During cooling operation, the four-way switching valve 13 is held in the state shown by the solid line in Fig. 3. The expansion valve 23 is controlled so that the valve opening is fully open. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 15 via the four-way switching valve 13, and condenses by exchanging heat with the outdoor air.

[0106] The condensed refrigerant passes through the first connection point S1, the check valve 17b, and the fourth connection point S4 of the bridge circuit portion 17 and flows into the liquid pipe 19a of the liquid-gas heat exchanger 19. The refrigerant flowing through the liquid pipe 19a exchanges heat with the refrigerant flowing through the gas pipe 19b and is subcooled.

[0107] The refrigerant that flows through the liquid pipe 19a is temporarily stored in the high-pressure receiver 21. The refrigerant that flows out of the high-pressure receiver 21 passes through the fully open expansion valve 23, and is diverted to each of the second expansion valves 24a, 24b, 24c, and 24d via the second connection point S2, the check valve 17c, and the third connection point S3 of the bridge circuit unit 17, and is reduced to a predetermined low pressure. The refrigerant that has been reduced in pressure by each of the second expansion valves 24a, 24b, 24c, and 24d exchanges heat with the indoor air in the corresponding indoor heat exchanger 35a, 35b, 35c, and 35d and evaporates. The indoor air that has been cooled by the evaporation of the refrigerant is blown into the room by the corresponding indoor fan 37a, 37b, 37c, and 37d to cool the room.

[0108] The refrigerants evaporated in the indoor heat exchangers 35 a , 35 b , 35 c , and 35 d join together in the gas refrigerant pipe 6 , pass through the four-way switching valve 13 , and flow into the gas pipe 19 b of the liquid-gas heat exchanger 19 .

[0109] The refrigerant flowing through the gas pipe 19b exchanges heat with the refrigerant flowing through the liquid pipe 19a and becomes superheated vapor. The refrigerant flowing through the gas pipe 19b passes through the accumulator 27 and is sucked into the compressor 11.

[0110] (2-2) Heating operation During heating operation, the four-way switching valve 13 is held in the state shown by the dashed line in Fig. 3. Also, each of the second expansion valves 24a, 24b, 24c, and 24d is controlled so that each valve opening is fully open. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into each of the indoor heat exchangers 35a, 35b, 35c, and 35d via the four-way switching valve 13, and condenses by exchanging heat with the indoor air.

[0111] The indoor air heated by heat exchange with the refrigerant is blown out into the room by the corresponding indoor fans 37a, 37b, 37c, and 37d, heating the room.

[0112] The refrigerant condensed in each indoor heat exchanger 35a, 35b, 35c, 35d flows into the corresponding liquid refrigerant pipe 5a, 5b, 5c, 5d and reaches the corresponding second expansion valve 24a, 24b, 24c, 24d. Because the second expansion valves 24a, 24b, 24c, 24d are fully open, the refrigerant passes through and joins the second expansion valves 24a, 24b, 24c, 24d without being reduced in pressure.

[0113] Thereafter, the refrigerant passes through the third connection point S3, the check valve 17d, and the fourth connection point S4 of the bridge circuit portion 17 and flows into the liquid pipe 19a of the liquid-gas heat exchanger 19. The refrigerant flowing through the liquid pipe 19a exchanges heat with the refrigerant flowing through the gas pipe 19b and is subcooled.

[0114] The refrigerant that has flowed through the liquid pipe 19a is temporarily stored in the high-pressure receiver 21. Then, the refrigerant that flows out of the high-pressure receiver 21 is reduced in pressure to a predetermined low pressure by the expansion valve 23. The reduced-pressure refrigerant passes through the second connection point S2 of the bridge circuit unit 17, the check valve 17a, and the first connection point S1, and flows into the outdoor heat exchanger 15. In the outdoor heat exchanger 15, the refrigerant exchanges heat with the outdoor air and evaporates.

[0115] The refrigerant evaporated in the outdoor heat exchanger 15 flows into the gas pipe 19b of the liquid-gas heat exchanger 19 through the four-way switching valve 13. The refrigerant flowing through the gas pipe 19b exchanges heat with the refrigerant flowing through the liquid pipe 19a and becomes superheated vapor. The refrigerant flowing through the gas pipe 19b passes through the accumulator 27 and is sucked into the compressor 11.

[0116] (3) Charging refrigerant into the outdoor unit 120 Typically, the refrigerant is filled after the outdoor unit 120 and the indoor units 30a, 30b, 30c, 30d are connected via liquid refrigerant pipes 5a, 5b, 5c, 5d and gas refrigerant pipes 6 at the installation location of the air conditioning apparatus 100. The lengths of the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipes 6 are determined depending on the installation positions of the outdoor unit 120 and the indoor units 30a, 30b, 30c, 30d.

[0117] However, in the air conditioner 100 of the present embodiment, a non-azeotropic refrigerant mixture is used, and there is a high risk that the composition ratio will change when the refrigerant is charged after installation, so that risk needs to be reduced.

[0118] Therefore, the heat source circuit 120a of the outdoor unit 120 is pre-filled with an amount of refrigerant corresponding to the amount of refrigerant required in the refrigerant circuit 110 when the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipe 6 have a predetermined first length L1. The first length L1 is a length that makes it unnecessary to additionally fill the refrigerant into the refrigerant circuit 110 formed by connecting the outdoor unit 120 and the indoor units 30a, 30b, 30c, 30d via the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipe 6. In this embodiment, the first length L1 is set to 30 m.

[0119] The refrigerant is filled into the outdoor heat exchanger 15, the liquid-gas heat exchanger 19, the high-pressure receiver 21, the accumulator 27, and the pipes connecting them, which are included in the heat source circuit 120a of the outdoor unit 120.

[0120] The amount of non-azeotropic refrigerant mixture pre-filled in the outdoor unit 120 is, for example, two to three times the amount of R32 refrigerant required for the entire refrigerant circuit 110 when R32 refrigerant is filled into the refrigerant circuit 110 in which the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipe 6 are set to a first length.

[0121] In this embodiment, in order to increase the amount of refrigerant that can be pre-charged in the outdoor unit 120, the pipe diameter in the outdoor unit 120 is made larger than the pipe diameter in the indoor units 30a, 30b, 30c, and 30d.

[0122] In addition, in order to ensure that the amount of refrigerant pre-filled in the outdoor unit 120 is sufficient for the amount of refrigerant required for the entire refrigerant circuit 110, the volume ratio of the outdoor heat exchanger 15 to the total volume of the indoor heat exchangers 35a, 35b, 35c, and 35d is set to 3 or more.

[0123] Furthermore, by setting the volume ratio of the high-pressure receiver 21 to the outdoor heat exchanger 15 within the range of 0.04 to 0.6, the amount of refrigerant pre-filled in the outdoor unit 120 can easily satisfy the amount of refrigerant required for the entire refrigerant circuit 110.

[0124] The installation work of the air conditioning apparatus 100 consists of a process of installing the outdoor unit 120 and the indoor units 30a, 30b, 30c, 30d at the installation locations, a process of connecting the outdoor unit 120 and the indoor units 30a, 30b, 30c, 30d via liquid refrigerant piping 5a, 5b, 5c, 5d and gas refrigerant piping 6, and a process of sending the refrigerant filled in the outdoor unit 120 to the refrigerant circuit 110.

[0125] In the process in which the refrigerant filling the outdoor unit 120 is sent to the refrigerant circuit 110, the liquid side shutoff valves 25a, 25b, 25c, and 25d and the gas side shutoff valve 26 are opened, thereby filling the refrigerant circuit 110.

[0126] (4) Features (4-1) In the air conditioner 100, the outdoor unit 120 and the indoor units 30a, 30b, 30c, and 30d are connected via liquid refrigerant pipes 5a, 5b, 5c, and 5d and gas refrigerant pipes 6 at the installation location to form a refrigerant circuit 110. The refrigerant filled in the refrigerant circuit 110 is a non-azeotropic refrigerant mixture having a temperature glide of 1°C or more during evaporation and condensation. The lengths of the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipes 6 are determined according to the installation positions of the outdoor unit 120 and the indoor units 30a, 30b, 30c, and 30d. The lengths of the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipes 6 are set in advance to a first length L1 (for example, L1 = 30 m) at which additional filling of the refrigerant into the refrigerant circuit 110 is not required. The outdoor unit 120 is pre-filled with an amount of refrigerant corresponding to the amount of refrigerant required for the refrigerant circuit 110 when the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipe 6 have the first length L1.

[0127] It is not easy to charge a non-azeotropic refrigerant mixture on-site while maintaining its composition ratio. Therefore, in this air conditioner 100, the refrigerant is charged into the outdoor unit 120 in advance, and the composition ratio of the non-azeotropic refrigerant mixture can be maintained by eliminating the need for on-site charging.

[0128] (4-2) In particular, when using R454C, which has a temperature glide of 5° C. or more during evaporation and condensation, it is difficult to charge the refrigerant on-site while maintaining the composition ratio. Therefore, in this air conditioner 100, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant mixture is maintained, by charging the outdoor unit 120 with the refrigerant in advance.

[0129] (4-3) The liquid refrigerant pipes 5a, 5b, 5c, and 5d are preferably 2.5-section pipes (outer diameter 7.93 mm) or more. When using a non-azeotropic refrigerant with a large pressure loss, the diameter of the liquid refrigerant pipes 5a, 5b, 5c, and 5d must be large, and the amount of refrigerant charged increases. The greater the amount of charge, the greater the risk that the composition ratio of the refrigerant will change during on-site charging. Therefore, in this air conditioning device 100, there is a great advantage in pre-charging the outdoor unit 120 with the refrigerant, in that the composition ratio of the non-azeotropic refrigerant is maintained.

[0130] However, if the actual piping lengths of the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipe 6 exceed the first length L1, additional charging of refrigerant becomes necessary, further increasing the risk of a change in the refrigerant composition ratio. In order to reduce the risk of a change in the composition ratio in such a situation, the liquid refrigerant pipes 5a, 5b, 5c, and 5d are suitable as 2.5-section pipes from the standpoints of both "suppressing pressure loss" and "suppressing the amount of additional refrigerant charged."

[0131] (4-4) The amount of the non-azeotropic mixed refrigerant pre-filled in the outdoor unit 120 is 2 to 3 times the amount of R32 refrigerant required in the entire refrigerant circuit 110 when a single R32 refrigerant is filled in the refrigerant circuit 110 in which the liquid refrigerant piping 5 and the gas refrigerant piping 6 are set to the first length L1. Some non-azeotropic refrigerants require two to three times the amount of R32 refrigerant, which has a zero temperature glide, and there is a high risk that the composition ratio of such refrigerants will change when they are filled on-site. Therefore, in this air conditioner 100, there is a great advantage in that the composition ratio of the non-azeotropic refrigerant is maintained by filling the outdoor unit 120 with the refrigerant in advance.

[0132] (4-5) Since the diameter of the pipes in the outdoor unit 120 is larger than the diameter of the pipes in the indoor units 30a, 30b, 30c, and 30d, the amount of refrigerant that can be pre-charged in the outdoor unit 120 can be increased.

[0133] (4-6) The ratio of the volume of the outdoor heat exchanger 15 to the total volume of the indoor heat exchangers 35a, 35b, 35c, and 35d is equal to or greater than 3. This allows the amount of refrigerant pre-filled in the outdoor unit 120 to be sufficient for the amount of refrigerant required in the entire refrigerant circuit 110.

[0134] (4-7) The high-pressure receiver 21 is connected between the outdoor heat exchanger 15 and the expansion valve 23. The volume ratio of the high-pressure receiver 21 to the outdoor heat exchanger 15 is within a range of 0.04 to 0.6. The amount of refrigerant that can be pre-charged in the outdoor unit 120 can include an amount of refrigerant equivalent to the internal volume of the high-pressure receiver 21.

[0135] (4-8) The refrigerant circuit 110 is provided with a liquid-gas heat exchanger 19 that exchanges heat between a high-pressure liquid refrigerant and a low-pressure gas refrigerant. The liquid-gas heat exchanger 19 is a double-pipe heat exchanger. The amount of refrigerant that can be pre-filled into the outdoor unit 120 can include an amount of refrigerant equivalent to the internal volume of the liquid-gas heat exchanger 19.

[0136] (5)Other The worker installing the air conditioner 100 determines whether the lengths of the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipe 6 required for installing the air conditioner 100 are equal to or shorter than the first length L1.

[0137] If the length of the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipes 6 is less than the first length L1, the amount of refrigerant filled in the outdoor unit 120 is the same as or greater than the required refrigerant amount, so the additional refrigerant filling step is not necessary. Therefore, the additional refrigerant filling step is not performed, and after the outdoor unit 120 and the indoor units 30a, 30b, 30d are connected via the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipes 6, the installation work is completed.

[0138] In other words, the amount of refrigerant filled in the outdoor unit 120 is equal to or greater than the amount of refrigerant required in the refrigerant circuit 110 when the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipe 6 are equal to or shorter than the first length L1.

[0139] On the other hand, if the length of the liquid refrigerant pipes 5a, 5b, 5c, 5d and the gas refrigerant pipe 6 exceeds the first length L1, the refrigerant pre-filled in the outdoor unit 120 is insufficient to meet the required amount of refrigerant, so a process of additionally filling the refrigerant is required.

[0140] Therefore, a refrigerant additional charging process is performed, and an amount of refrigerant according to the lengths of the liquid refrigerant pipes 5a, 5b, 5c, and 5d and the gas refrigerant pipe 6 is additionally charged into the refrigerant circuit 110. The refrigerant is additionally charged from the service port of the liquid side shut-off valves 25a, 25b, 25c, and 25d or the gas side shut-off valve 26, for example.

[0141] Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0142] 1, 100 Air conditioning equipment 5 Liquid refrigerant piping (piping) 5a, 5b, 5, 5c Liquid refrigerant piping (piping) 6 Gas refrigerant piping (piping) 10, 110 Refrigerant circuit 11 Compressor 15 Outdoor heat exchanger (heat exchanger) 20, 120 Outdoor unit (heat source unit) 20a, 120a Heat source circuit 21 High pressure receiver 23 Expansion valve (pressure reducer) 24a, 24b, 24c, 24d Second expansion valve (pressure reducer) 25 Liquid side shutoff valve (first shutoff valve) 25a, 25b, 25c, 25d Liquid side shutoff valve (first shutoff valve) 26 Gas side shutoff valve (second shutoff valve) 30 Indoor unit (utilization unit) 30a, 30b, 30c, 30d Indoor units (utilization units) L1 First length [Prior art documents] [Patent documents]

[0143] [Patent Document 1] International Publication WO2013 / 111180

Claims

1. A heat source unit configured to be connected to a utilization unit (30) via pipes (5, 6) at an installation location to form a refrigerant circuit (10), The refrigerant filled in the heat source unit is a non-azeotropic refrigerant having a temperature glide of 1° C. or more during evaporation and condensation, the heat source unit is pre-filled with an amount of the refrigerant required for the refrigerant circuit (10) when the length of the pipes (5, 6) is a first length (L1) at which additional charging of the refrigerant into the refrigerant circuit (10) is unnecessary; A heat source unit (20).

2. The refrigerant circuit (10) is formed by connecting one utilization unit (30). The heat source unit (20) according to claim 1.

3. The utilization units (30a, 30b, 30c, 30d) are connected in parallel to form the refrigerant circuit (10). The heat source unit (20) according to claim 1.

4. The temperature glide during evaporation and condensation of the refrigerant is 5° C. or more; A heat source unit (20) according to any one of claims 1 to 3.

5. The pipe (5) is configured to be connected to a 2.5-minute pipe (outer diameter 7.93 mm) or more through which a liquid refrigerant or a gas-liquid mixed refrigerant flows. A heat source unit (20) according to any one of claims 1 to 3.

6. The pipe (5) is a 2.5-branch pipe (outer diameter 7.93 mm), A heat source unit (20) according to claim 5.

7. the amount of the refrigerant pre-filled in the heat source unit (20) is 2 to 3 times the amount of R32 refrigerant required in the entire refrigerant circuit (10) when the refrigerant circuit (10) in which the pipes (5, 6) are set to the first length is filled with R32 refrigerant; A heat source unit (20) according to any one of claims 1 to 3.

8. The first length is 30 m. A heat source unit (20) according to any one of claims 1 to 3.

9. A first shutoff valve (25); A second shutoff valve (26); and a heat source circuit (20a) that is a flow path of the refrigerant from the first stop valve (25) to the second stop valve (26) and is configured to form a part of the refrigerant circuit (10); Equipped with The heat source circuit (20a) A compressor (11); A heat exchanger (15); A pressure reducer (23); Including, the compressor (11), the heat exchanger (15) and the pressure reducer (23) are connected in series; The heat source circuit (20a) further includes a high-pressure receiver (21) connected between the heat exchanger (15) and the pressure reducer (23). A heat source unit (20) according to any one of claims 1 to 3.

10. The volume ratio of the high pressure receiver (21) to the heat exchanger (15) is within the range of 0.04 to 0.

6. A heat source unit (20) according to claim 9.

Images